Monthly: February 2015

Water jet cleaning.

Introduction.

In the sugar, energy, metallurgy, chemical, shipbuilding and other industries there is a need to use devices enabling the removal of contaminants arising in technological processes or during their operation.

Removal of impurities can be done mechanically or hydraulically. The effectiveness of cleaning depends on the amount of pressure generated in a given place to burst the contaminated sediment, regardless of the method used. In mechanical cleaning, burst pressure is caused by the sharp ends of the cleaning brush or knife blade. In hydraulic cleaning, it is caused by the water jet generated by the high-pressure pump. Using the hydraulic method of removing impurities gives:

  • high cleaning efficiency,
  • ability to remove dirt in hard-to-reach places,
  • employing a small number of employees (practically two operators),
  • using water as a cleaning agent, which is available in virtually all conditions.

These features result in the increasingly wider use of this method in industry.

The article describes the high-pressure cleaning device type WUC-1 manufactured by POWEN SA and presents the manufacturer's technology and experience in removing contaminants using this device.


1

Figure 1. WUC-1 High Pressure Cleaning Device. 1 – T-65/45 plunger pump, 2 – ZR-100/45 discharge valve, 3 – ZP-100/50 overflow valve, 4 – cleaning nozzle, 5 – lance, 6 – high-pressure lines, 7 – electrical equipment, 8 – manual ball valve or foot valve, 10 – water filter.


Construction, principle of operation, technical data and accessories of the WUC-1 device.

The WUC-1 device is shown in the photo and in Figure 1. The pump (item 1) sucks water from the hydrant or pipeline through the filter (item 10) and pumps it through the discharge valve to the supply main (item 6). This pipeline is made of sections of high-pressure hoses with a nominal diameter of dn = 12 mm and a working pressure of pr = 45 MPa. At the end of the power supply bus there is built-in cleaning equipment:

  • manual shut-off ball valve (item 8), foot valve (item 8) or manual gun,
  • fixed or flexible lance (item 5),
  • fixed or rotating cleaning nozzle (item 4).

The water flow system (from the filter through the pump, discharge valve, hoses, lance and nozzle) is designed for the pressure generated by the pump, i.e. pr = 45 MPa. The discharge valve switches the pump to idle speed when the pump reaches a pressure of 45 MPa. During this time, the pump sucks water from the filter and pumps it back to the filter without pressure. If the discharge valve jams or hangs up, the pressure in the system increases to approximately 50 MPa and the overflow valve, located on the pump valve block, opens, through which the pump pumps water from the outside. In this way, the pump and the entire hydraulic system are protected against overload.

Technical data of the WUC-1 device

  • Pump capacity – 65 dm3 / min
  • Working pressure – 45 MPa
  • Engine power – 55 kW
  • Supply voltage – 380 or 500 V
  • Engine shaft rotation speed – 1475 min-1
  • Device weight -1225 kg

WUC-1 device accessories.

Depending on the application, the WUC-1 device can be equipped with various types of cleaning accessories. This equipment is always installed at the end of the bus. It includes: a hand or foot valve, a fixed or flexible lance, a fixed or rotating nozzle or a hand gun. The foot valve is opened and closed by the operator's foot. By pressing the pedal with your foot, it causes the liquid to flow through the valve, and when you remove it, it immediately closes the valve - cutting off the water flow from the valve to the lance. The foot valve is used when cleaning long pipes, e.g. in evaporators. Figures 2 and 3 show various versions of the lance. Figure 2 shows a fixed lance made of a pipe with an outer diameter of 20 mm (lances are also made from a 16 mm pipe), while Figure 3 shows a flexible lance that is used for cleaning bent pipes in heating devices.


Figure 2. Lance < p20

Figure 2. Lance < p20.

Figure 3. Flexible lance.

Figure 3. Flexible lance.


Four types of fixed nozzles are provided for cleaning the pipes from sediments and scale, shown in Figure 4 (items 2, 4, 5 and 4). Fixed nozzles (items 5, 2 and 2) produce a stream in the direction of lance travel, while the nozzle (item 4) produces a stream of liquid in the opposite direction. In the case of a nozzle (item 3), the recoil force pulls the lance with the nozzle into the pipe. The nozzle (item XNUMX) allows you to clean pipes completely clogged with sediment or scale. The nozzle (item XNUMX) has a single hole and is designed to work with a hand gun.

Figure 5 shows the rotating nozzle. It is used to clean pipes or channels with a circular (cylindrical) cross-section.

Depending on the pipe diameter, a nozzle with the appropriate outer diameter and the required amount of water supplied, under appropriate pressure, is used. The WUC-1 device uses rotary nozzles with a maximum pressure. 45 MPa, with a water flow of 65 dm3/min.

Water cleaning efficiency.

Figure 4. Set of fixed nozzles.

Figure 4. Set of fixed nozzles.

Figure 5. Rotary nozzle Figure 6. Nozzle characteristics

Figure 5. Rotary nozzle. Figure 6. Nozzle characteristic data.


The effectiveness of water cleaning depends on the correct design of the cleaning system. The entire system - pump, water transport - pipes, conversion of water pressure into speed - nozzles, should be designed to create as little resistance as possible, as well as harmful turbulence and speed changes. Incorrect design, e.g. of the nozzle, or poor workmanship often leads to significant losses in water flow and loss of full effectiveness of the device.

In practice, this means that much higher water pressures are needed to achieve better efficiency of the device when using a bad nozzle. Assuming the optimal selection of the nozzle for the pump capacity and its correct implementation, the water flow rate from the nozzle will depend solely on the pump's operating pressure. You should always remember that the water leaves the nozzle in the form of a concentrated beam - a stream that remains in this form at a distance equal to approximately 100 diameters of the nozzle holes.

This is where the distance of the water jet works most effectively. By moving the nozzle away from the cleaning surface, we move the water stream away, which becomes fragmented and weakened further away due to the strong inhibition of individual water droplets by the surrounding atmosphere. This creates fog further away from the nozzle, which has virtually no effectiveness - Fig. 6.

When water droplets come into contact with a contaminated surface, the water droplets suddenly slow down, which causes a local pressure on the cleaned surface similar to the pressure of the water in front of the nozzle. The high pressure of water droplets acting on hard deposits causes them to crack, then water penetrates into the resulting cracks - fissures and breaks up contaminants, and in the final phase removes them from the surface. This use of a high-pressure water stream is particularly useful where it is impossible to reach the surface being cleaned with a sharp tool. It is necessary to properly select the angle "a", the outer diameter of the nozzle "D" and the diameter of the outlet holes "d" - Fig. 6, for each pipe intended for cleaning with a water jet.

Water pressure selection.

Research carried out on the practical removal of contaminants with high-pressure water shows that the water pressure depends on the type of sediment, the level of content and the hardness of the contamination layer.

Water pressure in the range of 11-18 MPa is used to clean: pipes, channels, oil tanks, ship bunkers, construction equipment, filter beds, air heaters, cast iron castings. This pressure is also used in the food industry to remove soft malt and fruit deposits.

Water pressure in the range of 18-30 MPa is used to clean water structures, ship hulls from alkaline accretions, foundry molds, and brick surfaces of building facades.

In sugar factories, water pressure of 30-45 MPa is used to clean technological equipment. it is most difficult to remove scale in steel pipes with a nominal diameter of 0-33 mm installed in evaporators.

For cleaning pipes made of brass, the effective pressure is 30-35 MPa.
The WUC-1 device has the ability to regulate the pressure in the above range.

Selection of pump capacity.

Pump performance has a fundamental impact on cleaning efficiency. The greater the efficiency - the more water supplied at the required pressure, the more intensive the rinsing of contaminants. At the same time, as the efficiency and water pressure in the pump increase, the power of the engine driving the pump increases, and thus the weight and dimensions of the device. For specific operating conditions, it is possible to use a motor with a lower power.

Technology for cleaning evaporator pipes in sugar factories and pipes in energy equipment.

One of the most labor-intensive operations after a sugar campaign is cleaning evaporators. Each evaporator contains approximately 4000 pipes with a nominal diameter of 0-33 mm and a length of 3,2 m. The pipes are covered with limestone inside, which must be carefully removed to ensure their full patency and proper operation of the evaporator.

If there is a thick layer of stone and it is difficult to insert a 6-hole radial nozzle into the pipe to be cleaned, a 3-hole blade nozzle with a large angle of inclination of the holes through which water flows out is used. The sharp face of the nozzle allows it to enter the overgrown pipe, and the 3 oblique holes ensure initial bursting and removal of scale from the pipe. As practice shows, in order to thoroughly clean the pipe, it is necessary to clean it again with a 6-hole radial nozzle or a rotary nozzle. In the case of pipes with an internal diameter of less than 30 mm covered with stone, a 6-hole front nozzle or a rotary nozzle should be used.

Energy devices often have bent heating pipes. Cleaning such pipes is possible with a 6-hole suction nozzle, which has outlet holes directed in the opposite direction to the direction of pipe cleaning. It should then be attached to the flexible lance (Fig. 3). The flow of water through the nozzle holes creates a force that pulls the nozzle together with the lance into the pipe being cleaned. In this way, it is possible to clean pipes bent with gentle arcs, the bending radius of which is not smaller than the permissible bending radius of the flexible lance, which is R = 150 mm.


Figure 7. Cleaning the evaporator pipe dn = 33 overgrown with limestone.

Figure 7. Cleaning the evaporator pipe dn = 33 overgrown with limestone.


Summary.

The WUC-1 device was subjected to operational tests during a renovation campaign at the Racibórz sugar factory. It was used to clean 7 evaporators with a total amount of approx. 28 thousand. pipes. The overall performance of the device was assessed positively. Further positive experiences with the WUC-1 device were obtained when cleaning tanks in sewage treatment plants.

Roman Pawlik.

The article was published in issue 2 of the "Pompy-Pompownie" magazine in 2000.

 


Author's comment after 15 years:

“In my opinion, the article has not lost its relevance after 15 years and its content is still valid. The WUC-1 device, after appropriate verification of the documentation in terms of compliance with current regulations, may be offered by GPW SA on the market.


 

 

 

 

 

"From Łazarkiewicz's school" - Zygmunt Froehlke


Last Name engineer Szczepan Łazarkiewicz was known at the Gdańsk University of Technology from the very beginning 50swhen I was a student at this university. After graduating, I came to Warsaw especially to work under his leadership.

I was a young, ambitious graduate packed with various information. Confrontation of my knowledge base with knowledge and experience engineer Szczepan Łazarkiewicz it turned out very pale. He showed me how much I still need to learn to gain complete knowledge about pumps.

Engineer Łazarkiewicz was the doyen of Polish pumping. He contributed significantly to the development of the design of modern pumps in Poland. Even when he had an established position as a pumper, he willingly took the risk of introducing new solutions. Thanks to this, a number of pump structures for the energy industry were introduced into production, for example large diagonal pumps for Ostrołęka, Goczalkowice, Turów.

He was a very upright, consistent, fair man, demanding of himself and others. His diligence, punctuality and factual assessment of each of our work earned him high recognition. He rarely gave praise, but to be praised by him was a great honor. He tried to supervise all work in the design office.

It is often said today: "he is from the Łazarkiewicz school." This means a person committed to work, performing his tasks at a high level. He has always been the driving force behind our actions. He raised a lot of engineers who try to continue his work.

At the Warsaw Pump Factory, we had the opportunity to work with the most outstanding practitioner of technical knowledge in the field of centrifugal pumps in Poland. Acquired skills developed in “School of engineers. "Szczepan Łazarkiewicz" are especially visible today, after a dozen or so years.


From the article by Zygmunt Froehlke, Nestor of Polish pumping, "Wafapomp", 1976, no. 13 (129).

Zygmunt Froehlke, employee of the Warsaw Pump Factory in 1955-1974, successor
Mieczysław Stępniewski as the chief designer.

Cooperation between the user and the pump supplier from initial arrangements to renovations.

Pumping and operating a pumping station is generally not the core business of the company. It is usually an auxiliary or side process, treated as a "necessary evil" that is a source of costs and problems. These costs are often significant. Some estimates indicate that about one-fifth of all electricity production is used to drive pumps. Other components of pumping station operating costs, such as maintenance and renovation costs, are also significant. Maintaining the continuity of pumping station operation is in many cases a problem that absorbs the attention of the company's management. Minimizing pumping costs and ensuring continuity of traffic requires specialist knowledge, not always available in companies whose core business is something else. In modern economics there is a clear tendency to the so-called "outsourcing", i.e. companies focusing on basic tasks and outsourcing all side tasks to specialized companies.

Pumping and operating a pumping station is a typical task that can be advantageously outsourced to specialists. There are two basic stages in this task. One is the selection and purchase of devices, and the other is operation.

Design offices traditionally provide assistance to users at the device selection stage. This is usually a good solution because the designer, thanks to his knowledge of the designed process and the wide market offer, is able to suggest the user the optimal solution. However, there are cases where this is not the case, which may be due to several reasons:

  • Some designers are not independent at all, but are affiliated with device manufacturers. These may be capital connections, common in the case of large international concerns taking shares in Polish design offices. However, some smaller design offices collect commissions from manufacturers for recommending their devices. The selection of pumps in such a case is not objective at all. On the contrary, devices from preferred manufacturers are biasedly promoted in a way that does not take the user's interests into account.
  • Sometimes the reason is simply routine and the desire to limit the scope of work. Instead of conducting an extensive comparative analysis aimed at optimal selection, the designer recommends a device whose catalog he has on the shelf.
  • Some offices specializing in the design of specialized processes do not have employees with sufficient knowledge of pumps and pumping systems.

Moreover, even in cases where the designer reliably fulfills the task of selecting the optimal pumps, his role usually ends there and the user is left alone with the problem of operation and maintenance. For the above reasons, in order to efficiently deal with pump problems, the user should remain in contact with the pump manufacturer. Cooperation between the user and the producer is difficult because in a market economy their interests are seemingly opposite, because increasing profits for one of them takes place at the expense of reducing them for the partner. The user therefore treats the manufacturer's offers not as proposals for the objectively best solutions, but as the most profitable proposals for the manufacturer. Despite this, it is possible to build long-term relationships based on trust, because for a serious manufacturer, customer satisfaction is more important than a one-off, high profit, which allows for obtaining subsequent orders.

In addition to the problem of lack of mutual trust, there are other factors that make dialogue between the user and the manufacturer difficult.

  • Pumps are often purchased through intermediaries. Not every manufacturer maintains its own sales network and the strategy of many companies assumes sales through intermediaries. There is nothing wrong with this, as long as the intermediary company has the expertise needed to select the pump correctly. However, it also happens that the intermediary is unable to collect the necessary information, and what's worse, for fear of his commission, he tries to prevent direct contact between the user and the manufacturer. As a result, manufacturers receive inquiries about "an unsubmersible pump for medium-low density sludge, Q = 10m3/h, H = 10-15 m", or a pump with the following parameters: "minimum pressure of 2 atmospheres at 10 taps % inch each, water circulation 15-25 m, lifting height approx. 2-2.5 m. Water at the last settling tank cleaned approximately 20%” (quotes from authentic requests for offers from intermediaries).
  • Pumps often constitute only a small part of the value of a turnkey installation. In such a case, the contractor often does not attach much importance to their selection, focusing only on the price and delivery date, because the issues of operation after the warranty period are not important to him. In such cases, in order to simplify purchases, complete deliveries from one manufacturer are preferred, without paying attention to the correct selection of individual pumps and without consulting the user who will operate the installation after its start-up.
  • In tenders for facilities financed from external sources (e.g. European funds), formal requirements are often too extensive and dominate over technical issues. In the latter case, in some cases, specifications are imposed without justification, preferring imported devices, which are often in contradiction with Polish regulations and engineering practice.

In general, it should be stated that the tender procedure is not always the optimal purchasing method. Theoretically, the tender is supposed to ensure equal opportunities for all competitors and lead to the selection of the most advantageous offer. In practice, if there is bad will on the part of the contracting authority, while maintaining the appearance of a fair tender procedure, it may make a biased choice. For this purpose, it is enough to include in the technical specification the features relating to a specific product or to informally provide additional information to the preferred supplier. Therefore, the tender does not constitute a reliable protection against abuse, but it has the following unfavorable features:

  • The tender procedure is expensive for both the buyer and the supplier. Preparing an offer that meets usually extensive formal requirements is time-consuming. Since, by definition, only one out of several tender offers wins, the supplier must include the cost of preparing offers in the product prices. The buyer must bear the cost of preparing the tender documentation, as formal deficiencies may constitute the basis for appeals and questioning the results of the procedure.
  • The tender procedure is time-consuming due to the time needed to prepare documentation, the time needed to prepare offers and their analysis. Moreover, there is a risk of being involved in an appeal or even court process.
  • The tender procedure makes communication between the user and the supplier difficult. For formal reasons, the requirements and parameters should be specified in advance, otherwise an accusation of tender manipulation may arise. Meanwhile, not everything can be predicted, as suppliers may propose better solutions that differ from the tender assumptions. The flexibility required to take advantage of such proposals is difficult to reconcile with the formal correctness of the tender.
  • A clear selection of an offer is only possible in simple situations, for example when the only criterion is price. In practice, the choice is usually multi-criteria, because in addition to the purchase price, operating costs are equally important, as are technical advantages that are difficult to convert into money (e.g. ecological safety, noise level, etc.). In addition to difficulties in correctly selecting the weights of individual criteria, there may be difficulties in verifying the reliability of offers. . Some bidders may make unrealistic promises regarding, for example, the intervals between renovations, which can only be verified after the purchase.

For some entities, making purchases in the form of a tender is a formal and legal requirement, and in other cases it is advisable when there is a fear that the people representing the buyer do not sufficiently care about the interests of their company, which may result from negligence or putting personal interests ahead of them. However, if the company's interest is secured in another way, for example through effective corporate supervision, it may be more effective to make purchases in a different manner.

A beneficial form may be permanent cooperation with a supplier selected on the basis of experience in operating existing devices, the advantages of which over competitive products have been confirmed in practice. This does not mean a restriction of competition, because in the current market conditions, the inflow of other offers is continuous, which allows for ongoing verification of the competitiveness of the equipment of a regular supplier.

Constant cooperation ensures proper communication between the user and the manufacturer. It can cover a wide range of elements.

Signaling future needs.

For each manufacturer, it is very important to understand the future demand for pumps in terms of new design solutions and parameters in advance so that it is possible to complete the construction work before making the purchase. Traditional market research methods, for example in the form of surveys, are not always effective. Direct indication of future needs by the user benefits both parties. The manufacturer limits the risk associated with investing in a new product, while the user receives a product that strictly meets his needs.

Providing information needed for correct selection under conditions of proper communication.

During regular contacts, you can practice effective procedures for selecting new pumps. The user knows which parameters are necessary to make the optimal selection and can determine them, while the manufacturer, knowing the user's conditions, does not have to request a full, standard set of information every time. As a result, an optimal selection can be made with a limited risk of error and a moderate amount of work. The existence of free two-way communication is also important. In the conditions of permanent cooperation, the manufacturer not only responds to specific requests for offers containing specific parameters, but also has the opportunity to discuss the adopted solutions, propose alternative solutions and verify the parameters.

Conclusion of a long-term contract for the supply of pumps.

Under conditions of permanent cooperation, it is possible to agree on deliveries for a longer period, for example a year. This allows the manufacturer to reduce prices by reducing marketing costs and better production planning. In addition to price discounts, the user benefits in the form of a guarantee of on-time deliveries and more favorable payment terms, which do not have to be strictly related to delivery dates. There is also a reduction in costs in the procurement department.

The manufacturer's involvement in repairs and maintenance.

The direct benefit of the user from constant cooperation with the manufacturer is that the maintenance services are familiar with the devices used, which reduces training costs and limits the risk of incorrect operation. However, if the user considers it beneficial to limit his own maintenance services, the manufacturer may take over some of the tasks in this area. It is able to offer regular customers of its pumps the following forms of service:

  1. Reactive – a traditional form of service in which the manufacturer responds to the customer's request (usually when problems occur).
  2. Control – in addition to responding to the customer's request, the manufacturer carries out periodic inspections, adjustments, advice and training (e.g. checking alignment, checking bearings, adjusting stuffing boxes, verifying working conditions).
  3. Full – the manufacturer undertakes full maintenance (i.e. planning and organizing renovations under the customer's control).
  4. Operation of the pumping station at a price determined per m3 – the manufacturer undertakes a comprehensive service consisting in pumping, including renovation. Determining the price per pumped cubic meter allows you to clearly decide which type of pump is the most economical. Attempts to determine this at the stage of individual tenders do not always give correct results. When a pump manufacturer undertakes to pump at a price per cubic meter, it assumes actual responsibility for representations regarding the actual operating costs of the pumps.

If users are interested, the manufacturer is able to enter into negotiations about providing a selected form of service, more complex than the traditional, reactive one that is used as standard.

Renovation management is closely related to the issue of spare parts delivery dates. It would be advisable to implement a system dividing spare parts into categories depending on the frequency of their replacement and the scale of production of a given type of pump. There may be five categories, marked, for example, with letters A to E, as in the table.

For individual categories, the manufacturer could specify guaranteed delivery times, for example:


 

 

tab1

Table 1. Spare parts categories.

A – on the shelf
B – 7 days
C – 14 days
D – 30 days
E – 60 days


The affiliation of individual parts to different categories should be determined by the manufacturer and communicated to the user. You should be aware that maintaining a stock of spare parts involves costs. It should be possible to negotiate the composition of individual categories with regular customers. It should be added that commissioning the pump manufacturer to carry out repairs completely frees the user from the problem of the delivery time of spare parts. To sum up, it should be said that establishing permanent cooperation between the user and the pump manufacturer brings tangible benefits to both parties. Such cooperation may be formalized in the form of a contract or remain informal, based on long-term contacts and trust. Further forms of permanent cooperation include:

  • full user standardization
  • the so-called "global partnership", where the user - a large international company - uses pumps from one manufacturer in all its plants around the world.

Before concluding cooperation agreements, it is necessary to consider whether the benefits resulting from reducing purchase and renovation costs outweigh the losses associated with limiting the freedom of choice of pumps.

Dr. Eng. Grzegorz Pakula


The paper was presented at the 6th Forum of Pump Users and Manufacturers.

It was also published in the "Pompy-Pompownie" magazine.


Author's comment after 15 years:

"Even though the text was written 15 years ago, it remains largely up-to-date. A disturbing phenomenon is the intensification of the tendency to exceed formal and legal requirements in tender specifications for pumps, which was already signaled 15 years ago. Comparison of the volume occupied in specifications, for example by the description of requirements regarding bank guarantees, the format in which documents are required, etc., with the volume occupied by the description of technical requirements, indicates a clear advantage of the former. Very often, standard documents containing general and irrelevant requirements are published as technical specifications, while failing to specify parameters that are crucial for the selection of the pump. It is becoming common practice to include general contract templates in tender specifications that are not suitable for a given case, such as, for example, transferring all clauses of the contract for the construction of a power unit concluded between the general contractor and the energy company to the pump sub-supplier. You may get the impression that many tender specifications are written by lawyers and economists rather than technicians. Of course, creating the correct formal and legal structure for the contract is important, but this cannot exclude the agreement on essential technical issues. Design offices, with some notable exceptions, often "don't feel the need" and are unable to properly formulate requirements or selection criteria. At the same time, however, a positive tendency can be noticed, which is that, despite formal and legal difficulties, the cooperation between pump manufacturers and users postulated in the article works in many cases. Over the 15 years since the text was written, there have been numerous examples of establishing partnership cooperation in the form proposed, thanks to which pump systems have been designed and implemented at a high technical level and their operation is carried out correctly. Nevertheless, the call for partnership cooperation in the technical field remains valid."

 

 

"Lathe and rifle" - Stanisław Monarski


Parents of Stanisław Monarski (Mondszajna): Henryk and Michalina née Czernuszewicz, Kiev 1916.


Our family name is Mondszajn. In German it is written Mondschein. Mond is the moon and Schein is the light. Both words put together mean "moonlight." Everyone knows the "Mondschein Sonate", i.e. the "Moonlight Sonata" by Ludwig van Beethoven. From the notes of my father Henryk, I determined that my great-grandfather, Karol Mondszajn, married my great-grandmother, Franciszka Fejga. They both lived in the Czech town of Bystřice pod Hostýnem in the Austro-Hungarian partition. Karol was a carpenter by profession.

From this union, W. was born in Bystřice 1868 year my grandfather, who in adulthood took over the carpenter profession from his father. At baptism he was named Franciszek.

Franciszek Mondszajn's future wife - Władysława Helena Szyling - was born 15 March 1868 year. She was the daughter of Andrzej Szyling, an Evangelical denomination, a blacksmith by profession, and Leonora Szyling née Zienkiewicz, a resident of the village of Łukowo near Maków Mazowiecki. The Zienkiewicz family, appointed by King Jan III Sobieski, was included in the so-called gołota nobility. My grandmother's parents lived in Warsaw. Andrzej Szyling was the owner of a horse-drawn carriage, which he operated himself. He was buried at the Bródno Cemetery.

Franciszek Mondszajn and Władysława Helena Szyling, Leonora's daughter, got married June 10 1888 year in Warsaw, in the Praga district. The copy of the marriage certificate is the first document I have found in which the surname Mondschein is given correctly.

Franciszek and Władysława Helena, i.e. my grandfather and my grandmother, lived in Praga at 18 Grochowska Street (before the numbering change), on Lake Kamionkowski. My father, who was their oldest child, was born 30 May 1890 year. He had two sisters - Leokadia and Stefania - and a brother, Jan. My grandfather was a carpenter and an avid fisherman. In autumn 1904 year, while fishing, he fell into Lake Kamionkowskie. He caught a cold, contracted pneumonia and died. He was 36 years old. After Franciszek's death, Władysława Helena took over the full care of the children. Later, Henryk helped her support her family, who, while attending a craft school, became an installer of water supply turbine pumps and steam turbines intended for hydrodynamic plants supplying water and electricity to residents of large cities.

When he was fifteen, his father joined a locksmith's apprenticeship Adam Waszniecki at the street Trębacka 13. He finished it after three years - 1 Września 1908 year. He received a journeyman's book. He was unemployed for over a year. Only January 22 1910 year he got a job in Locksmith Factory of Leon Ogórkiewicz and Jan Zagórny.

2 February 1911 year he was employed as a fitter at Zakłady Mechaniczne Brandel, Witoszyński i S-ka. My father started earning well. He could support his mother and siblings. In his youth, he practiced mountain climbing and wrestling with his friends in the "Sokół" sports club.

W 1914 year, the Kiev authorities presented the factory Brandel offer for the purchase and commissioning of water pumps. After talking to his father, the factory owners sent him to Kiev to fulfill the order. After arriving at the place, my father learned that the contract had been extended to include the installation of a steam turbine with a generator in the leather tannery in Berdyczów.


Parents of Stanisław Monarski (Mondszajna): Henryk and Michalina née Czernuszewicz, Kiev 1916.

Parents of Stanisław Monarski (Mondszajna): Henryk and Michalina née Czernuszewicz, Kiev 1916.


After assembling and commissioning the power-hydraulic units, Henryk did not have time to return to Poland. The revolution caught up with him. At that time, his mother, sisters and brother were also in Kiev with him, whom he invited to visit.

My father lost his job at a water pump station in Kiev. He took a job as an orderly at a local hospital. After completing the course, he became a steam engine driver. He drove freight and passenger trains on the Kiev-Berdyczów route.

W 1919 year, while working as a train driver in Soviet Ukraine, he met my mother, Michalina Czernuszewicz, née Stebanowska. Her family lived in Berdyczów. My mother, my grandmother, came from a Polish family, and my father, my grandfather, came from a Ukrainian family.


Henryk Monarski (in the middle) at the lathe.

Henryk Monarski (in the middle) at the lathe.


W 1922 year everyone returned to the country. My parents lived in a single room in a single-story wooden house on the street Prince Janusz (now Olbrachta) in Wola. The parents had three sons and a daughter, Janina. I was born June 23 1924 year.

Shortly after settling down modestly, my father started working at... engineer Stefan Twardowski in a factory built on Grochowska. It was already a plant with an extended production profile. On November 11, 1918, Stefan Twardowski started producing steam turbines. Weakened by the difficult living conditions in Ukraine, my father fell ill with typhus. He was in the Infectious Diseases Hospital on Wolska Street. His condition was so serious that a priest was called to administer last rites to him.

During my father's stay in the hospital, my mother was looking for a job. She was helped by the descendants of Gustaw Gebethner, the founder and co-owner of a well-known publishing and bookselling company in Warsaw. The square and the house where the parents lived were adjacent to the Gebethner estate. They became friends. Despite the difference in professions, their surnames brought them together: Gebethner-Mondszajn. With the help of the Gebethners, my mother was accepted to work at the Szlenkier Factory. The parents got married January 25 1923 year in the Church of St. Stanisława on Wolska Street.

While working at the engineering plant Stefan Twardowski, In addition to his profession as a specialist in centrifugal pumps, his father also became a steam turbine fitter. He was a respected and talented professional. It was a long way from home to work. Trams did not reach Ksiącia Janusza Street. He had to get to Młynarska, and then he had to change trains to Grochowska. Only in 1929 a tram line was connected to Ksiącia Janusza Street.

My father led the team that assembled the products manufactured at the plant of Eng. Twardowski pump in the Fast Filter Plant. The facility was officially launched on March 23, 1933 - on the 50th anniversary of the existence of waterworks and sewage systems - by President Ignacy Mościcki.

Stefan Twardowskiand he was not only a high-class specialist, but also a very humane boss in relation to his employees. He provided them with, among other things, material assistance in building their own houses near Warsaw. My father also benefited from this help, deciding to build a two-story family house at Bocheńskiego Street (formerly Sosnkowski) in Nowy Rembertów. Next door, on the same street, two-story houses were built by my father's siblings: Leokadia, Jan and Stefania. Leokadia graduated from the Faculty of Philology of the University of Warsaw and got a job at this university. Jan - a turner, worked at Polskie Zakłady Lotnicze. Stefania taught Polish, history and geography at school.

In order to ensure the pace and quality of the house construction, we moved from Ksiącia Janusza Street to Nowy Rembertów. The carpenter Antoni Frankiewicz and his family offered us a place to stay. Nowy Rembertów was experiencing a construction boom at that time. It was quickly built next to the "old" Rembertów, located on the left side of the railway line.


From the left: Stanisław Monarski and Edward Czerwiński junior.

From the left: Stanisław Monarski and Edward Czerwiński junior.


We moved to an unfinished building - we took a premises on the ground floor. The remaining members of my father's family came from Warsaw and, like us, they lived in single rooms of unfinished houses. At that time, I was attending the first grade of a private school in Stare Rembertów at ulica Gwiazdacka, because the primary school was still under construction. Mom was pregnant - 17 Września 1931 my brother Zdzisław Wojciech was born in the same year.

The father often went away to assemble pumps and steam turbines, so the mother, in addition to taking care of her sons, had to deal with construction. The construction of family houses was completed in 1933 year.

During the summer holidays, before entering the first grade of junior high school, August 1937my father took me to Rumia. He was to assemble and run centrifugal pumps in a pumping station supplying drinking water to Gdynia. My joy was great. For me it was a great trip.

We left in the evening by passenger train. In the morning the train stopped in Gdańsk. A Prussian gendarme in a navy blue uniform entered our compartment. On his head he had a very shiny metal helmet with a German eagle on it. He checked his ID documents and left the compartment. After a while, Polish soldiers entered and did the same thing. When the train started moving, I asked my father to explain the incident. He said that we had crossed the Polish-German border. We arrived in Rumia at noon. My father had already ordered a room - accommodation with meals - from the farmer Kashubia. It was harvest time. My father went to work at the pump station, and the farmer took me with him to the field, to which we were transported by a team consisting of a wagon and two chestnut horses. He let me ride his horse bareback until I fell off.

I visited my father at the pumping station several times and admired his mastery as a pump fitter.

W 1939 I turned fifteen last year. I attended primary school in Nowy Rembertów and two classes of junior high school run by the Order of Salesian Priests in Sokołów Podlaski.

After the Germans entered Poland, the production of industrial plants was stopped. The father was unemployed. Our mother saved us from great poverty. She opened a store - a grocery store selling pre-occupation products. After restarting by engineer Stefan Twardowski the factory's father started working there again. The demand for steam pumps and turbines also increased due to war damage.


Son of Edward Czerwiński (from the left) and Stanisław Monarski.

Son of Edward Czerwiński (from the left) and Stanisław Monarski.


Young people were not only deprived of the opportunity to study, but were also exposed to many dangers from the Nazis. Therefore, three employees - Szczepan Łazarkiewicz, Edward Czerwiński and my father - turned to the owner of the plant with a request to employ their family members. Engineer Stefan Twardowski he accepted their requests. He took Edward Czerwiński's sons: Edward and Stefan to learn the locksmith profession. To learn the profession of a turner - Leszek Łazarkiewicz, nephew of the pump designer, Eng. Szczepan Łazarkiewicz and me. Leszek Łazarkiewicz's friend, Ryszard Laskowski, worked at the plant. Leszek Łazarkiewicz and Ryszard Laskowski, like me, lived in Rembertów and were active in underground organizations throughout the occupation, in Independent Poland, Sword and Plow, and from 1942 brand year in the Home Army. Leszek took the conspiratorial pseudonym "Atos" (like one of the musketeers), Ryszard - "Qvintus" (fifth), and I - Parvus (small). Every morning we met at 6:30 at the Rembertów station and went to work together. In the morning, the wagons on the electric trains on the Mińsk Mazowiecki-Warszawa Wschodnia route were so overcrowded that we could only get on after "fighting a fight". Packed like sardines in a can, we reached Wschodnie, and from there we reached the factory on foot or by tram.

The entrance to the plant was guarded by two guards: Jan Drzazga, a night watchman, and Wojciech Kowalski, a former driver of the plant's owner. In the morning, after ringing the bell, Wojciech Kowalski always opened the door. After greeting our colleagues, we went to the cloakroom to put on our work clothes.

After changing clothes, we took up our workstations. Leszek at the lathe shop - his vocational teacher was Karol Kuch. Ryszard - in the tool shop operated by locksmith Antoni Anterszlak. He was my first machining teacher Jan Mondszajn, my father's brother, who worked at the Polish Aviation Works in Warsaw before the war. In the production hall, in addition to the machining machines being driven by belt transmission, there were four lathes operating "Beryngers" with individual electric motor drive and Norton gearbox. "Beryngers" served by: Boniface Stolarkiewicz, Józef Raczko, Bronisław Perkowski and Wacław Szymański. IN 1940 year, during mass round-ups, the Germans took Bronisław Perkowski and tracer Marian Dudek to Auschwitz. The position of tracer was taken by Aleksander Karczewski. Bronisław Perkowski returned, and Marian Dudek died of exhaustion.

I started learning metal machining - under my uncle's supervision - by turning pins with a cylindrical and conical collar ending with an inch thread for a nut. They were intended to connect electric motors with turbine pumps and steam turbines with power generators. Ignacy Złotkowski taught me how to use a heavy hammer to season lathe knives and harden them in olive oil and water to a blue color. The first contact with him was disastrous. Instead of hitting the tip of the red-hot knife, I hit the anvil. The hammer jumped back, freed itself from my hands, and fell to the floor. Mr. Ignacy's reprimand was appropriately strong. Science has not gone to waste. Such an incident never happened again.


From the left: Leszek Łazarkiewicz (turner) and Ryszard Laskowski (locksmith).

From the left: Leszek Łazarkiewicz (turner) and Ryszard Laskowski (locksmith).


My lathe was against the wall. From the windows I could see the entrance to the office, and behind it our neighbor - Polskie Zakłady Optyczne. My uncle was working next to me on the left. They worked for me: Henryk Stanisławskand on the second lathe and boring machine, and the oldest turner among the employees, Teofil Fernik. Every day at eight o'clock the master of the tool shop Antoni Anterszlak he recommended to the student Ryszard Laskowski launching two belt transmissions in the production hall. At this signal, the seventy-person crew began work. He came to the office before nine o'clock - I saw him through the window - head of the technical department for turbine testing, engineer Wacław Twardowski. The following people also came to the office at this time: production manager Stanisław Kruś, gchief designer engineer Szczepan Łazarkiewicz and accountant Bohdan Kozerski, which paid "weekly wages" on Saturday. The interns hired with me earned about PLN 150 a week. I gave the first "emoluments" I received for work to my father and mother.

Unexpectedly - for both me and my father - Jan Mondszajn left the plant engineer Stefan Twardowski. He was admitted to the telephone plant (Dzwonkowa) at Grochowska Street. We were both very disappointed with his decision because I had not yet learned many of the steps required to operate a lathe. Especially the operation of cutting various types of inch and metric threads with even and odd pitches and setting gears in the "guitar".

My worry didn't last long. Master Wincenty Piotrowski, my father and Henryk Stanisławski they informed me that Mr. Stanisławski he will take care of me until I receive the title of journeyman. Stefan Twardowski During the occupation, he organized a kitchen and a canteen in two rooms adjacent to the raw materials warehouse, where tasty regenerative soups were served during breaks - between 12 p.m. and 12:30 p.m. He also ordered a grain mill to be made and placed in the room, where workers could process grain into flour or groats. This example encouraged illegal, side-production, the so-called a job to satisfy their own household needs, which the owner of the plant and the foreman looked at with a pinch of salt.

Carbide tubes were also made on the side, especially useful in towns near Warsaw, where there were frequent power outages. Equipment for producing moonshine from rye, molasses or sugar was also manufactured. Locksmith colleagues made locks and special bolts for turners to protect against burglary in basements and rooms.

In addition to learning the profession of a turner, I had the opportunity to try my hand at performing on stage. The head of Primary School No. 2, Zdzisław Sosnowski and Maria Pigułowska, decided to take care of former students by creating an amateur youth theater. The school's huge gym allowed the organization of such a theater. During the occupation, my friends: Janina Wróblewska, Zofia Wysocka and Barbara Korzeniowska performed on this "stage". And also colleagues: Marian Łączyński, Jan Świdziński, Tadeusz Janczar (then still bearing the surname Musiał), Józef Nalberczak, Tadeusz Bienias, Jan Pytka, Zbigniew Neffe and Ryszard Laskowski.

A team of young amateurs led by Zdzisław Sosnowski and Maria Pigułowska
he staged, among others: "Fat Fish" by Michał Bałucki, "Maiden Vows" by Aleksander Fredro and "The Cottage Behind the Village" based on the novel by Józef Ignacy Kraszewski.

The following actors played in "Chata za village": Zofia Zarzycka (Aza), Ryszard Wilczyński (Tumry), Leszek Łazarkiewicz (matchmaker). I was entrusted with the role of Aprash, which - like the others - I learned at home and at work on the lathe, during the initial operations of the so-called skinning.

Before the premiere, our director, Maria Pigułowska, asked me to get a permanent wave to look like a Gypsy. The parents agreed to this. My hair caused a sensation in the factory. I went to work and returned to Rembertów with my friend Leszek Łazarkiewicz. One day - after changing my hairstyle, but before the premiere of "The Cottage Behind the Village" - when, as usual, we were walking together after work to the Eastern Railway Station, on the corner of Targowa and Grochowska streets I noticed two Germans in field gendarme uniforms. One of them reacted strangely when he saw me. After walking a few steps, I heard a shout: "Halt!" Halt! I approached the gendarme. He demanded an Aussie or a Kennard card. When I started to take out my ID card from the inside pocket of my jacket, the gendarme suddenly took out a parabellum pistol from the holster and shouted: - Hände hoch! — at the same time he pressed the barrel of the gun into my stomach. The second gendarme took out his ID card and started repeating my name loudly. He asked if I was a gypsy. Knowing German was useful to me. I replied that I was Polish. I answered the next question about whether I was a Jew in the same way. I also explained that I worked as a turner in a pump factory. - Komm mal her! - ordered one of the gendarmes and took me to the gate. There he said that I was not a Jew. He gave me back my ID card and told me to go away. After returning to Rembertów, before I went home, I stopped at a hairdresser. I had myself reduced to a bald state. The next day, my head, from which the perm and black "Gypsy" hair had disappeared, made a great impression at the factory. During the meal break, I told my friends about everything.

W July 1942 year, after sixteen months of work on a lathe with a belt drive from the transmission, foreman Wincenty Piotrowski i Henryk Stanisławski they called me and told me that I was to take over the lathe shop "Beryngera", where Bronisław Perkowski worked. It was a joyful surprise for me. I was recognized as a good and efficient employee.

The lathe I was entrusted with had an individual drive connected to a gearbox, unlike a belt one. On such a lathe, the spindle rotates for skinning and finishing parts and connecting gears on the guitar in the box for threading
inch and metric sizes could be set with the appropriate lever position. Her service gave me satisfaction and job satisfaction.

I always remember my guardian and vocational teacher with great respect. It is to his credit that the foreman entrusted me with a modern lathe.

There was camaraderie and mutual kindness among the interns.

SEPTEMBER 16, 1942 year (my father was on a field trip) I left for work in the morning. On the way to the railway station, I met my friends Leszek Łazarkiewicz and Ryszard Laskowski. The wind was so strong that we had to force it and walk along the sidewalk, leaning low. When we entered the platform, people waiting for the electric train to arrive looked in silence towards the "old" Rembertów. Right next to the station, ten bodies were hanging on two gallows. They were hanged Poles - Pawiak prisoners, underground activists, mainly soldiers of the People's Guard and members of the Polish Workers' Party. The sight of dead figures swaying in the wind, the creaking of wooden gallows and the dead silence of people gathered on the platform increased the stress.


On October 16, 1942, ten Pawiak prisoners were hanged at the railway station in Rembertów.

On October 16, 1942, ten Pawiak prisoners were hanged at the railway station in Rembertów.


There was a constant shortage of wood used to light peat or coal in the kitchen and stove, so I went to the forest with my friends to get wood. One day, two Wehrmacht soldiers arrested us. They took us to the Rembertów artillery training ground and locked us in a cell. The Germans told us that we would be deported to the Reich for forced labor. This calmed us down a bit, that they wouldn't shoot us.

In the evening, the cell door opened and the German translator informed me and two friends: Knap and Kes that we were released from custody. It was a great surprise and relief for us. It turned out that we owed our release to names. Our families explained that they were of Austrian origin. Four bottles of moonshine also helped. A stopped and hidden radio receiver with an antenna was the source of information transmitted from England by Polish reporters. We were happy to hear about the frontline successes of English, American, French, Polish and Soviet troops.

The news broadcast on the radio about the great defeat of the Germans near Moscow was confirmed by numerous railway transports with wounded German, Spanish and Italian soldiers passing through the station in Rembertów from east to west.

W May 1943 year - after completing a course in the use of small arms of various calibers and designs, German-made stud grenades, and field communications equipment - the Home Army in Rembertów ordered tactical exercises.

The lecturers of this specialty were Eugeniusz Bocheński, pseudonym "Dubaniec", and Stefan Łyszkiewicz, pseudonym "Pechowiec". On Sunday at six o'clock in the morning, about two hundred unarmed Home Army soldiers took a position in the line in front of the Buchaka forest, along Działyńscy Street. We made a mock attack on the triangulation point in the town of Groszówka, located east of Rembertów. The exercise was discussed at the triangulation tower. The order to disperse was given around nine thirty.

My friends came back with me: Zdzisław Awiło, Jan Pytka, Tadeusz Bienias. The sun behind us was shining brightly. Walking through the thickets and bushes, we saw single flashes of light, and in a moment a mounted unit of German soldiers moving on a dirt road towards the triangulation point. We were lucky that the exercise ended early. Besides, the flashes from our polished helmets saved us.

April 10 1944 In the same year, the Home Army liquidated Gestapo informer Artur Fischer at 16 Olbrachta Street (currently Republikańska Street) in Rembertów. The sentence was carried out by "Julian" - Władysław Granowski. My friend, Home Army member "Atos" - Leszek Łazarkiewicz - took part in the action.

My father, anticipating the imminent end of the war and the possibility of an offensive of Soviet troops on Warsaw, which could end in the destruction of the plant, asked engineer Stefan Twardowski for issuing me a certificate confirming employment at the Mechanical Plant.

At the end of August, the roar of artillery guns coming from the east and the flights of combat planes with a red star on their wings gave hope that the liberation of Rembertów by Soviet troops was approaching. The fact that the Germans had lost the war was evidenced by the numerous medical trains with freight wagons full of wounded Wehrmacht soldiers passing through Rembertów to the west.

At the beginning August 1944 year, Wehrmacht soldiers began taking men from their homes to an organized forced labor camp on the premises of "Pocisk" in Rembertów, where fuses and artillery shell heads were produced before the war. My father told me to hide in our hiding place, saying that they wouldn't take him because he was quite old - he was 54 at the time. It happened differently than he expected. They took him away. On the third day, my distraught mother asked me to report to the camp myself and take care of my father. The same day, my mother and I went to "Pocisk". We saw a camp fenced with barbed wire. There were quite tall guard towers in its corners. My friends and their fathers were behind the barbed wire. The German camp commandant eagerly agreed to my request to volunteer to work in the camp. I entered the gate. My father was dissatisfied, but then it turned out that my mother's decision was right because she saved us from losing our lives.

In "Pocisk" we had to dismantle production equipment and load it onto freight wagons. After completing this work, we were ordered to cut down pine trees in the local forest and build the so-called Spanish goats. We delivered them to the second line of German defense. After setting them up, we returned to the camp under the convoy. We drank a canteen of water and went to bed in our clothes. At night, floodlights from the towers illuminated the entire camp.

In the camp, the translator was a Ukrainian in a Vlasovsky uniform - Jan Kazimierchuk. He warned my father about his intention to move the camp and advised him to escape with me. We escaped during another chojak logging. Hiding in the dense forest and bushes, we reached the house. After dinner, we hid in camouflaged hiding places in the attic to rest for the night.

The Ukrainian saved our lives. Ryszard Knap, my friend, was transported with other "campers" to East Prussia, to the region of Masuria. He dug trenches and built dams with Spanish goats. Then, together with others, he was deported to Mauthausen. He died there
from exhaustion.

9 Września 1944 year we woke up to planes flying at low altitude and the sounds of exploding bombs. One of them made the whole house shake. An hour later we heard the tramp of people running and serial gunshots. When the shots stopped, we came out of hiding. We saw Soviet soldiers. Their parents welcomed them and thanked them for their deliverance.

11 September the recruitment of young people into the Polish Army began. Zygmunt Duszyński - commander of the Volunteer Fire Department in Rembertów, commander of the People's Guard of the Right Bank of Warsaw, and later deputy minister of national defense - proposed that the Home Army members jointly join the Polish Army. I expressed my desire to join. My colleagues from the Home Army did the same: Tadeusz Bienias, Zdzisław Awiło, Jan Pytka and Jan Świdziński.

I became a soldier of the 2nd heavy machine gun company "Maksim" of the 6th Infantry Regiment of the 2nd Infantry Division of the First Polish Army. We took up firing positions on the embankment of the right bank of the Vistula, on the right side of the destroyed railway bridge, opposite the Warsaw Citadel.

I commanded the CKM "Maksim" team and was the liaison between the commander of the 2nd CKM company and the commander of the 2nd battalion of our regiment. While performing a liaison task, I met Leszek Łazarkiewicz and Ryszard Laskowski. They both served in the same regiment as me. Ryszard in the 1st battalion was, like me, the commander of the CKM team. Leszek served as a guard at the regiment's headquarters. We were lucky. We survived the Nazi occupation and service on the front line. After the war, during social gatherings, we often recalled this period. Ryszard Laskowski w 2007 he turned 80 years old this year. After the war, he was a radio officer in a high-seas fishing fleet. He lives in Świnoujście. I am still in constant contact with him by phone.

Our friend Leszek, unfortunately, died in... 2005 year.

When I commanded the CKM team as a corporal and then, after leaving the front, I was a student of the Infantry Officers' School No. 2 in Lublin, my father assembled pumps and turbines on Grochowska Street for the power plant in Powiśle, destroyed during the Warsaw Uprising. Soviet specialists helped in its reconstruction - the USSR provided the necessary building materials. Zakłady Mechaniczne Eng. Stefan Twardowski made turbine and pump units for the power plant. They were assembled by factory workers under the supervision of Henryk Mondszajn (Monarski). The first turbine set of the Warsaw Power Plant was launched April 25 1945 year. The ceremonial opening of the power plant took place in the presence of President Bolesław Bierut, Prime Minister Edward Osóbka-Morawski and Minister of National Defense General Michał Rola-Żymierski.

My father took a well-deserved retirement in January 1967 year. He worked as a locksmith and fitter for a total of 61 years. He died May 4, 1972, aged 82.

In birth, baptism, marriage and other documents, our family name was often written with serious errors that my ancestors did not pay attention to.

Because of the Mondszajn surname, my parents and I sometimes encountered humorous and, during the occupation, unpleasant life-threatening situations. Therefore, in order to avoid harassment, in consultation with my parents and with our successors in mind, January 30 1962 year we changed our name to Monarski.


Henryk Monarski (Mondszajn), an excellent field fitter, was called the ambassador of the Warsaw factory. The pumps installed by Henryk Monarski supplied, among others: water to the inhabitants of Gdynia.


Col. M.Eng. retired Stanisław Monarski, son of Henryk Monarski,
employee of the Mechanical Plant, Eng. Stefan Twardowski in the years 1941-1944.

Pumps for liquids containing solids.

Introduction.

The process of pumping mixtures of solids and liquids is common in industry, especially in industries such as:

  • hard coal mining,
  • metal ore mining,
  • power engineering,
  • metallurgy,
  • cement and lime industry,
  • construction aggregates industry,
  • sugar industry.

Pumping mixtures of solids and liquids has its own specificity and differs in many respects from the process of pumping homogeneous liquids, e.g. clean water. A significant problem is the diversity of mixtures in terms of their characteristics, including the way they affect the pumping installation. Depending on the type of solid, its granulation (granulometric composition), concentration, shape and grain size, the pumped mixture may have different erosion properties, density and viscosity.

The set of these features is important for the selection of pump installation elements and construction materials. The pump, as the most important device in the process of pumping mixtures of solids and liquids, is subject to particularly high operational requirements. The basic criterion for pumps is their highest possible durability and the longest possible period of failure-free operation (so-called operational reliability). The second most important criterion when selecting a pump is energy efficiency. The purchase of relatively quickly wearing out elements of the flow system and relatively frequent repairs and renovations are the basic costs when operating this type of pumps. For this reason, the criterion of durability and failure-free operation has the greatest impact on the design, pump parameters and materials used.

Design features of slurry pumps.

To achieve high durability in extremely difficult operating conditions, it is not enough to use more resistant materials while maintaining the design of the pump intended for clean liquids.

Pumps for mixtures of solids and liquids, referred to as slurry pumps, are characterized by certain specific design features. Most often, these are stationary, centrifugal, single-stage pumps.

In the past, tests were carried out using multi-stage pumps to achieve higher lifting heads. However, when pumping sludge, multistage pumps have significant operational shortcomings. The durability of interstage seals and guide vanes, exposed to the impact of solids flowing from the rotor at high speed, turns out to be unsatisfactory. There are also problems with blocking the flow system due to the smaller cross-sections found in multistage pumps. Moreover, disassembly and renovation of multistage pumps are more complicated and expensive. For these reasons, if there is a need to obtain significant lifting heads, when pumping sludge, it is more advantageous in practice to connect single-stage pumps in series.

Most slurry pumps are designed to operate with high inflow and high internal pressure. Slurry pumps usually have low speed characteristics due to the low rotational speeds used. These pumps use rotors of a special design with large cross-sections of inter-blade channels, enabling pumping of mixtures containing larger grains.


 

1

Figure 2. PH pump.

Figure 1. PH pump.

Figure 1. HC type pump.


The discs and rotor blades have significant thicknesses that determine durability. In order to enable pumping of mixtures containing large grains, single-sided open impellers or free-flow impellers are also used.

Blade rotors usually have a small number of blades, most often from l-5. The rotors are sealed with a front gap, regulated by the movement of the entire bearing assembly together with the rotor. The remaining elements of the slurry pump flow system, i.e. the casing, stub pipe and protective walls, have increased thicknesses, taking into account wear allowances and the increased pressure in the pump casing due to the possibility of working with inflow. Specially designed submersible pumps are often used to pump sludge. This is justified in cases where, for location reasons, it is impossible to create conditions for the stationary pump to work with inflow, which is necessary when pumping mixtures with a density above 1100 kg/m3. The flow system of these pumps has a similar structure to that of stationary pumps and is made of similar materials.

Construction materials used in slurry pumps.

When pumping clean liquids, even chemically aggressive ones, a passivation layer is formed on the surfaces of the flow system, preventing further corrosion. When pumping sludge, the protective layer is constantly removed due to erosion and the construction materials are constantly exposed to the corrosive effects of the flowing medium. The combined impact of corrosion and erosion places high demands on the materials used to make flow systems of slurry pumps. Special materials are used, most often high-alloy cast steel or cast iron, subjected to appropriate heat treatment, which ensures hardness in the range of 50-65 HRC and the required material structure.

Some non-metallic materials, e.g. rubber or polyurethane, combine high abrasion resistance with good anti-corrosion properties. Their weakness, however, is low mechanical strength and susceptibility to damage by larger bodies and sharp shapes. This limits their scope of use to slurries with small granulation and pumps with a moderate lifting height. In most slurry pumps, special materials are used for the impellers and replaceable linings located in an additional, external casing. This simplifies repairs and also frees materials exposed to erosion from stresses caused by internal pressure that are transmitted through the hull.

Conditions related to the selection of slurry pumps.

When selecting slurry pumps, different principles should be applied than when selecting pumps for clean liquids.

The service life of slurry pumps decreases quickly with increasing rotational speed, so you should not strive to use a direct drive with the synchronous speed of an electric motor, which is a common practice when pumping clean liquids. For slurry pumps, precise selection of rotational speed is required.

When there is variability of parameters over time, it is preferable to use variable speed drives, while for constant operating parameters, optimal adjustment of the pump to the system can be achieved by using an appropriate belt transmission and making a rotor with the appropriate diameter.

The natural tendency of users is to use single pumps even for high lifting heights, which requires high rotational speeds. Meanwhile, when pumping sludge, it is often more economical to connect pumps in series because, despite increased investment costs, savings are achieved thanks to longer periods between renovations.

The characteristics of slurry pumps provided by manufacturers are usually prepared for clean water. The parameters of the sludge pump are usually reduced compared to operation on clean water. There are no universal methods for converting characteristics from clean water to sludge. Individual slurry pump manufacturers use their own methods for this purpose, which may provide uncertain results for unusual mixtures.

An additional problem is the difficulty in determining the required lifting height, because users and designers are not always able to predict what the flow resistance in the installation will be, which results from the fact that the rheological properties of some sludges are difficult to predict. Please remember that when the flow rate drops below a certain value, solid particles settle and block the pipeline.

Taking into account the limited accuracy of the analyzes performed, it is advisable to equip the user with some options for regulating the parameters of the installed pumps. Often, it is sufficient to install a belt transmission in the pump unit, which allows, by changing the gear ratio (e.g. replacing the pulley), to adjust the pump's rotational speed to obtain the required parameters. The above-mentioned complications when selecting a sludge pump require close cooperation between the designer, user and pump manufacturer in determining all data regarding the pumped mixture, pumping installation, pump and drive selection. Slurry pumps manufactured by POWEN SA

The leading manufacturer and supplier of slurry pumps on the domestic market is POWEN SA, formerly operating under the name Zabrzańska Fabryka Maszyn Górniczej POWEN. The company has several dozen years of experience in the construction of slurry pumps, in the selection of appropriate construction materials and in the selection of pumps for hydrotransport systems. Over the last decades, pumps of the following series: KA, PŁP, PŁK, PŁS, PC, OŁ, PG, PŻ and PH produced by POWEN have satisfied the vast majority of the needs of the Polish economy in the field of sludge pumping.

Many years of experience have allowed us to develop a simple and safe design of PH pumps, equipped with flow system elements made of special alloy cast steel, guaranteeing their long service life. Produced in basic sizes: PH-65, PH-80, PH-100, PH-150, PH-200, PH-250, PH-300, these pumps have numerous versions and design variants.

The manufacturer's efforts were aimed at expanding the operating range of the pump series. The result was the PH-100W pump (Qn=100 m3/h, Hn =95 m), especially popular in the metallurgical industry.

Another direction of work was to increase the cross-sections of the flow channels. The result was pumps with free-flow impellers, type PH-100S. PH-150S and a PH-250M pump with a special vane impeller.

The PHP-150 vertical shaft pump was created based on the flow system of the PH-150 pump. PH pumps were adapted to pumping liquids at elevated temperatures, resulting in the PH-G series of pumps. The great popularity of PH pumps among users and the ongoing interest in these pumps are the basis for the continuation of their production by POWEN SA

In recent years, work has been carried out on a new series of slurry pumps. As part of a targeted project financed by the KBN in cooperation with the Central Mining Institute in Katowice and the Silesian University of Technology in Gliwice, the design of a series of HC pumps was developed.

When developing the design of these pumps, the need to improve some nodes to meet the operational requirements of users was taken into account. A new bearing unit was constructed without water cooling, and an oil filter was introduced. A specially designed stress reduction unit is used between the shaft and the rotor, facilitating disassembly. A design of the flow system was introduced, enabling various positions of the discharge port. A new, more durable construction material was used for the elements of the flow system.

Thanks to this, HC pumps are currently an attractive market offer of POWEN SA, successfully competing with the offers of foreign companies.

Another achievement of POWEN SA in the field of slurry pumps is the development and introduction into production of a submersible slurry pump type P-370. Used to pump a mixture of water and slag in one of the heat and power plants, it successfully competed with other foreign pumps of this type in terms of the durability of the flow system elements.

Summary.

The article discusses the issues of selection and operation of slurry pumps. The basic problems faced by users, suppliers and designers cooperating with them have been highlighted. Using the example of the main manufacturer of slurry pumps in Poland, POWEN SA, the tasks that the manufacturer must meet in order to provide modern slurry pumps that meet user requirements are discussed. Attention was paid to the advisability of cooperation between the user and designer with the pump manufacturer. POWEN SA, as a manufacturer of slurry pumps with many years of tradition and extensive experience, invites all interested parties to such cooperation.

MSc. Mark Coghen

The article was published in issue 6 of the "Pompy-Pompownie" magazine in 2000.


Author's comment after 15 years:

“The basic issues regarding pumping mixtures of liquids and solid particles presented in the article still remain valid. The products described 15 years ago, then produced by POWEN SA, are currently produced by the company - Powen-Wafapomp SA Group. The offer of slurry pumps has been extended, among others: o a series of MF pumps with rubber linings, HRC pumps for installation on suction dredgers, a series of HZ submersible pumps. The Powen-Wafapomp SA Group continues to work on further pump solutions, adapted to the increasing requirements of users.”


 

The influence of the regulation method on the vibration level of pump units operating in power units.

 


Summary.

Power units currently operate in a wide range of load variability, which translates into a wide range of pump performance adjustments, especially feed and condensate pumps. For this reason, it is important to choose the right regulation method, which should, above all, ensure high energy efficiency. However, the adjustment method also affects the vibration level. The nominal rotational speed of the pumps is selected at the design stage so that it is far from the critical speeds. However, during regulation by changing the rotational speed, there is a risk of resonance. Moreover, if the pump operates with a system with flat characteristics, which is typical for feed and condensate pumps, reducing the efficiency while maintaining the discharge pressure causes the pump to leave the optimal operating range. This causes internal recirculation flows, which are an additional source of forcing vibrations at frequencies other than rotational and blade frequencies.
The paper discusses the above phenomena and methods of limiting the increase in the vibration level.


1. Introduction.

An increased level of vibration of the pump unit shortens its service life, and if the vibrations are transmitted through the pipelines to adjacent elements, it also increases the risk of their damage. Therefore, the dynamic condition of pump units should be monitored, and if an increased level of vibration is found, the causes of this phenomenon should be determined and removed.

Mechanical sources of vibration excitations of pump units are widely known, such as misalignment of the pump and motor or unbalance of rotating elements. They give symptoms in the form of vibrations at the rotational frequency or its multiples and are relatively easy to diagnose and eliminate.

There are also hydraulic forces originating from recirculation flows and turbulence that appear in the pump when operating with a capacity different from the nominal one. This phenomenon becomes particularly important when power units operate within a significant range of load changes, reaching 50-100% of maximum power. Lowering the block parameters translates into a change in pump efficiency, which leads to their operation outside the optimal range.

When choosing a method for regulating pump parameters, one should take into account not only the minimization of energy consumption but also the reduction of the vibration level. Both aspects are interconnected, because vibrations forced by internal turbulence in the pump constitute a mechanism for the dissipation of hydraulic energy.


2. Danger of resonance when regulating by changing the rotational speed.

A dangerous increase in vibration levels occurs if the pump operates at a rotational speed close to the critical speed. To avoid this, pumps are usually designed so that the nominal speed is far from the critical speed. Most often, the first critical speed is at least 20% higher than the nominal speed. In the case of pumps with high nominal speed (above 3000 rpm), sometimes the first critical speed is below the nominal speed. These are the so-called "supercritical pumps". In their case, during start-up, the pump goes through resonance, and then after reaching the nominal speed, the vibrations stabilize.

When operating at a constant nominal speed, there is no risk of resonance resulting from operation near the critical speed. However, this risk cannot be ruled out in the case of speed control. First of all, in the case of "supercritical pumps", resonance may occur as a result of hitting the first critical speed. However, this danger also occurs for pumps for which the first critical speed is above the nominal one. Resonance may occur not only when the pump is operated at a speed close to the critical one, but also at a speed close to half of it. If, as is most often the case, the first critical speed is in the range of 1.2 - 1.4 times the nominal speed, then reducing the speed to 0.6 - 0.7 times the nominal speed as a result of regulation will lead to resonance. In practice, such a phenomenon usually does not pose a threat to feed pumps or condensate pumps in power units, because they operate in systems with flat characteristics (i.e. the discharge pressure changes relatively little with changes in efficiency), and this causes the range of rotational speed changes to be narrow, reaching down no further than 80% of the nominal speed. The phenomenon of resonance caused by the operating speed overlapping half of the critical speed is highly probable or even inevitable for deeply controlled pumps, where the change in rotational speed reaches down to 50% of the nominal speed. It is particularly dangerous for long vertical pumps, which are naturally more susceptible to vibrations.


If the pump, due to the wide range of parameter adjustments, is to operate with a drive with a frequency varying in the range of several dozen percent, encountering one of the resonance frequencies is basically inevitable. When selecting the pump, however, it should be ensured that the drive frequency at which the pump will most often operate is not close to the resonance frequency. Unfortunately, in practice this requirement is often ignored. Taking advantage of the fact that the variable speed drive makes it possible to easily change the pump parameters, the required analyzes are omitted, hoping that the parameters will be "adjusted on the inverter". If the pump achieves the most common parameters at the resonant frequency of the drive, it can be detuned by changing the impeller diameter. After reducing the impeller, the pump requires a higher rotational speed to achieve specific parameters, which allows it to move away from the resonance frequency.


3. Vibrations caused by hydraulic forces.

In addition to mechanical forces related to rotation, pumps also have forces arising from liquid flow. Their source is turbulence that occurs when the pump capacity differs from the nominal one. The blade angles in the flow system are designed so that, at nominal capacity, the flow to the impeller or guide blades is shock-free. However, when the pump operates with a capacity different from the nominal one, the direction of liquid inflow does not match the blade angle and vortices appear in the flow. (fig.1) When there is a significant difference between the current and nominal efficiency, recirculation flows appear in the inlet and outlet areas of the pump in the form of larger-scale vortices, which are a source of low-frequency vibrations. Collectively, these turbulences cause vibrations of various frequencies (noise), generally below the blade frequency.

Another factor forcing flexural vibrations of the pump shaft is the so-called axial thrust resulting from uneven pressure distribution around the impeller in scroll pumps, which occurs at capacities significantly different from the nominal ones.

iii

Fig.1. Swirl at the blade inlet.

It is generally accepted that the permissible operating range of the pump (fig.2) is from 0.8 to 1.1 of the nominal capacity. In this range, the vibration level is the lowest, while at lower or higher capacities the vibrations increase as a result of the hydraulic excitations described above.

eeee

Fig. 2 Dependence of the vibration level on performance.

With extensive throttling or bleed control, the pump often operates outside the recommended characteristic range and with increased vibration levels.
Using regulation by changing the rotational speed does not always prevent this phenomenon. For each rotational speed, the pump has a characteristic curve with a similar permissible operating range. As a result, on the collective chart for various rotational speeds, the permissible operating range in which vibrations are at a low level looks as follows: fig. 3.

rrrr

Fig. 3. Permissible operating range for variable speed.

If the regulation takes place in a system with flat characteristics, the change in efficiency takes place with a small change in pressure (lifting height), as shown by the arrow in the figure. fig. 3. In this case, the pump goes out of the recommended operating range, which results in an increase in vibrations. This situation occurs for feed and condensate pumps that operate in systems with flat characteristics, and with the current method of operating power units, their efficiency is often limited to 50% of the nominal level. This phenomenon is unavoidable for 100% pumps, which enter an unfavorable operating range when capacity is reduced. This can be avoided by using a larger number of pumps operating in parallel (e.g. 2 x 50%, 3 x 33%). In a 2 x 50% system, if there is a significant drop in efficiency, one pump can be turned off and the remaining pump operates in a favorable range. Therefore, in blocks intended for operation in a wide range of power regulation, it is more advantageous than 100% feed and condensate pumps to use a larger number of pumps operating in parallel, both in terms of energy and vibration levels.

In the case of pumps operating in parallel, if speed control is used, it should be applied to all pumps. A system used for cost-saving reasons, in which only one of the pumps operating in parallel has an adjustable rotational speed, is unfavorable because the pump, when the rotational speed is significantly reduced, begins to operate at too low efficiency and in an unfavorable range, which leads to a significant increase in vibrations.


4. Pumps regulated by changing the angle of the impeller blades.

In pumps in which parameters are regulated by changing the angle of the rotor blades, there are technological problems with proper balancing of the rotor, which may lead to an increase in vibrations at the rotational frequency. Rotors made using casting technology have shape errors resulting from shrinkage during the solidification of the metal in the mold and the resulting unbalance. A commonly used dynamic balancing method involves subtracting part of the material (e.g. by milling) at a fixed location. However, this treatment is only effective with a specific position of the shoulder blades. If the angle of their position is then changed, the balancing in the previous position is no longer effective. To avoid this phenomenon, blades with very limited shape errors should be used, which is difficult to obtain for castings. The blades should therefore be mechanically processed.

Increased vibration levels are also caused by increased clearances in the blade adjustment mechanism, which may occur after a certain period of operation.


5. Summary.

  • The method of parameter regulation used affects not only the energy consumption but also the level of vibration of the pumps, and thus their service life.
  • With a wide speed control range, there is a risk of resonance. This threat should be analyzed at the pump selection stage.
  • Regulation by changing the rotational speed in systems with flat characteristics (as for feed pumps and condensate pumps) leads to the pump leaving the recommended operating range. For this reason, it is advantageous to divide the required capacity into several pumps operating in parallel.

Dr. Eng. Grzegorz Pakula