Monthly: October 2014

"The sixth decade" - Józef Raczko

2014-10-290

"Sixth decade"

Intensive activities were already underway to build a new plant. The role of the members of the New Plant Construction Committee was to ensure that the initiatives they put into the project itself and its implementation were not distorted. It is necessary to emphasize the role of engineer Łazarkiewicz in the Committee, who - as an outstanding design mind - gave his all to ensure that nothing was omitted or neglected in the design or execution. Eng. worked with engineer Łazarkiewicz during the construction of the new factory headquarters. Mieczysław Stępniewski, deputy and intended successor of engineer Łazarkiewicz. He contributed a lot of effort and creative thought during construction. He was particularly interested in the rehearsal station. He fought to ensure that this part of the plant was made with a wide range of practical utility in mind. These two should be joined by engineer Kabała, who played a special role as a member of the Committee. He was taken into account. He was everywhere, saw everything through the practical eyes of the commissioning manager, and later the head of the chief mechanic's department. Stanisław Grossinger played a very important role in the Construction Committee. He was helped by his position as POP secretary. I believe that it can be said that he fulfilled his role on the Committee well for the plant. In 1960, the investment was started in Żerań Wschodnie, at 1 Odlewnicza Street.

The construction of the new facility was taken over by the investment service, whose director was Comrade Leon Lenobel. The Management of the Plant under Construction was established. After its liquidation, director Lenobel was appointed director of economic affairs in Żerań.

Former front-line soldier Leon Lenobel was the director of the Plant under Construction, and after opening the factory in Żerań, he became the deputy director of WFP for economic affairs.

It is worth mentioning the great contributions made to the plant during its construction and in subsequent years
chief investment specialist, engineer Janusz Walczyński. He was the chief engineer at Grochowska Street for some time. From this position he was appointed by the director, Eng. Doliński to the organizing management of the Plant under Construction. Engineer Walczyński liked to build, and he also took an active part in the creation of the company's Prophylactic and Recreation Center in Złockie near Muszyna. He died after an illness of several weeks 14 July 1980 year.

According to the project, a foundry department was to be established in Żerań simultaneously with the factory. However, due to deglomeration reasons, the project in this part was not approved. The foundry was to be built in Siedlce.

Od 1957 do 1963 year, i.e. throughout the entire period of construction of the new plant, I was the chairman of the Workers' Council. Due to my position, I took part in preparatory work, meetings and conferences. It is worth adding that all these construction activities were warmly supported by the entire staff, seeing it as a need to develop production and improve working conditions.

Wacław Tarnowski (right) was a master of vocational training.

The actions of the Committee and people cooperating with it were crowned with complete success.
The construction of the new plant began in 1960. She progressed very quickly. In day May 1961, XNUMX year, when engineer Kabała was about to leave for Żerań, the management recommended me to perform the duties of the head of the mechanical and assembly department for an indefinite period of time - they were waiting for the engineer. George Paszewin, who was supposed to take this position. At that time, the director, Eng., resigned. Władysław Tarnowski, and the director Wiesław Zahaczewski came.

Mieczysław Stępniewski left his job at the Warsaw University of Technology for WFP in 1958

At spring 1962 In the same year, Eng. became the start-up manager of the new plant. Jerzy Kabała. It was a right and happy choice. At Grochowska, he was the chief mechanic, head of the mechanical and assembly department, and head of production. He was a great practitioner and an excellent expert in the subject of production. He was very knowledgeable about machine tools, even the newest ones. Besides, he soon showed that he was doing well. He was not afraid or ashamed of work, and he often helped others, together with his masterful team, which included Franciszek Sitek.

Jerzy Kobała turned out to be the best prepared specialist to manage the start-up of the new plant in Żerań Wschodnie.

Jerzy Kobała turned out to be the best prepared specialist to manage the start-up of the new plant in Żerań Wschodnie.

Construction went very quickly. I moved to Żerań as the first supervisor, as a senior master, w May 1962 year, and in June, engineer Kabała launched the first lathe machine - the KCF carousel. At that time, there were already small lathes and a large arm drill at the stations. In the same year, offices and administration were moved from Grochowska. The crew received new, spacious production halls and a modern, most exemplarily furnished testing station in the country. There was no comparison with Grochowska. For example, a manual crane there and a mechanical crane here. Locker rooms there and locker rooms here. There is mechanized internal transport and generally good lighting. There are asphalt roads, large changing rooms and showers. There is an aesthetic cafeteria, although too small.

Factory in Żerań.

There was hope that if the plant was fully equipped, it would be the most modern in the country and one of the most modern in Europe. And they work based on their own, excellent documentation. But let's remember that the new plant grew out of the tradition of a small mechanical plant. He has traveled almost sixty years of work marked by the work of ambitious and dedicated people, company patriots.

The new plant based its production on extensive design knowledge and practical thought. Is it possible to assess the pumping achievements without the old plant? There was so much of it. In the Warsaw filter station, in waterworks in Lviv, Katowice, Maczki, in the sewage system in Warsaw, melioration in Pomerania, power plants in Ostrołęka, Łódź, Turów, Adamów, Halemba, Łagisza, in chemicals in Płock, Puławy, Tarnów and many other places. Who would count them?

Engineer Łazarkiewicz he left all his achievements in pomp, in drawings, in books and in people who worked with him and listened to him. He was the tutor of many engineers, pump specialists. They included: Eng. Mieczysław Witkowski, M.Eng. Zygmunt Froehlke, M.Eng. Janusz Witkowski, M.Eng. Bogusław Lato, M.Eng. Sławomir Kazimierczuk, M.Eng. Eugeniusz Skowroński, M.Eng. Ryszard Grabowiec, M.A engineer Tadeusz Grochowski, M.Eng. Andrzej Janson, M.Eng. Stanisław Jaźwiński, engineer. Stanisław Płatek, mechanical technician of Marcela Kuzyna.

Marceli Kuzyna stood at the drawing board at WFP for 33 years.

I mentioned engineer Łazarkiewicz so that I could answer the question: how many people were there in the old plant, maybe not as great as engineer Łazarkiewicz, but dedicated, exemplary and honest? People who raised themselves and others. People who sacrificed a lot to make the plant have a lot. Love for a company is measured by the same measure both for the one who is at a high level and for the one who is at a low level.

Eugeniusz Siury – deputy director of WFP for technical issues in the years 1963 – 1967.

There were many distinguished people, but many have already passed away. Today they are young and it is already clear that they have developed a love for the plant, for the Warsaw Pump Factory.

July 22 1963 year, the day of the National Day was for the Warsaw Pump Factory a historic day. A new plant in Żerań was commissioned. A ceremonial academy with a rich artistic program took place in the finished products hall. A new, third stage in the history of the plant has begun.

Director Wiesław Zahaczewski managed the factory during the breakthrough period of moving production for the large factory to Żerań and implementing licensed feed pumps.

When the new plant was launched, the deputy minister of heavy industry was M.Eng. Zdzisław Nowakowski. The director of the Association of Heavy Machine Construction Industry "Chemak" was Eng. George Dickman. The general director of WFP was Comrade Wiesław Zahaczewski.

The technical director was Eng. Eugeniusz Siury. The director of economic affairs was Comrade Leon Lenobel. The chief accountant was Bolesław Uniowski. The start-up manager of the new plant was Eng. Jerzy Kabała. The secretary of the PZPR Works Committee was Eng. Ksawery Janiszewski. The chairman of the Works Council and the head of company training was Jerzy Karniewski.

The head of production was engineer. Sulimir Stanisław Żuk. The head of the mechanical department was Eng. Mieczysław Witkowski. The head of the assembly department was Eng. Jerzy Paszewin. The main technologist was Eng. Tadeusz Sieklicki with his colleagues: Eng. Tadeusz Szuwar and Robert Pałaszyński. The main designer was Eng. Szczepan Łazarkiewicz, and his collaborator — M.Eng. Mieczysław Stępniewski. The tool management was headed by Eng. Stefan Lipski. The chief mechanic was Eng. Jan Szczepański.

Engineer Mieczysław Witkowski received a patent for the design of the hydraulic system of the 40R95 pump intended for the transport of agricultural produce.

Old problems ended and new ones began. The primary problem was the issue of human resources. Already in the first year after nationalization, a significant increase in production was noticeable, but there was also the problem of staff and training.

The management and social factors approached this matter quite energetically and did everything to not only maintain the number of staff, but also to increase it, taking into account the needs of the new plant. The idea of ​​organizing in-house training or a vocational school was born. This issue was resolved only when the plant was moved to Żerań.

After leaving WFP, Mieczysław Stępniewski returned to the Warsaw University of Technology.

To ensure a constant supply of staff, it was launched in 1962 the company's Basic Vocational School. The first year of its activity took place in an empty building of the plant on Grochowska Street. Manual work took place in the assembly hall. Already in the second year, the school was moved to a barracks in Saska Kępa, on Zwycięzców Street. It was not possible to place machine tools there, so the machine classes had classes in the post-construction barracks on the WFP premises in Żerań. Jerzy Karniewski was then the head of vocational training at the plant. The first graduates from the turning and locksmith classes came to work at the plant in 965. The plant and the school management fought hard for the construction of a new school in Bródno. It was built in 1969 at Łabiszyńska Street. The school is beautiful and modern. The facility takes good care of her. There are only few students and even fewer graduates for the company.

I worked for two years as a vocational teacher at the WFP Basic Vocational School. Then I returned to the mechanical department of WM1 in Żerań. For me, brought up in a workshop, working at school did not suit me.

In year 1963 the staff meeting elected me by acclamation as the company's social labor inspector and thus I became a member of the Presidium of the Works Council. I held the position of inspector for nine years, i.e. three terms of office - from April 1963 to May 12, 1972. I was the second social labor inspector since nationalization. I did not break the record because my predecessor, colleague Józef Krasnodębski, stayed in this position for four terms, from 1951 to 1963.

During my time as a social labor inspector, I completed a number of courses and training: district training in Warsaw and trade union training in Karpacz and Węgierska Górka, where I and Eugeniusz Popławski attended. I attended the course in Karpacz twice. My last training was a PCK course for commanders of social sanitary teams in... May 1968 year.

While working at the company school, I completed an occupational health and safety course organized by the school authorities for vocational schools. The organizer was the Verification Committee at the District Board of the Capital City of Warsaw. Warsaw. After the exam, the Board of Trustees issued me an appropriate certificate signed by the district probation officer and the chairman of the Verification and Examination Committee.In 1964 I was awarded the silver badge of the Metal Workers' Trade Union, and in 1966 - the gold badge.

On April 1, 1963, the Central Pump Research and Design Center was established. Another encouraging sign at that time was a significant increase in members of the Association of Polish Mechanical Engineers and Technicians (SIMP). It already consisted of thirty engineers and fifteen technicians. The SIMP circle was established in 1961 - initially it had thirteen members.

Andrzej Durek – director of WFP in the years 1969 – 1971.

In the years 1963–1970, production increased rapidly at the Warsaw Pump Factory in Żerań. In July 1963, at the turn of the six months, the Conference of Workers' Self-Government for the first time increased the tasks of the production increase plan for 1964 from 25 to 55 percent, i.e. to the total amount of PLN 95 million.

As reported by M.Sc. Eng. Andrzej Durek, then CEO of WFP, in the period from 1963 to 1968 year global production increased by 511 percent and total employment by 263 percent. In the old plant, the global production value ranged from PLN 20-30 million per year. In Żerań, there was truly explosive growth.

000132

Production in the years 1963-1969.

At the same time as the quantitative increase, there was a sharp increase in the range of manufactured pumps. Within the approved specialization, the range of pumps has been significantly expanded based on the technical ideas of the company's design office. During the period 1963-1968 Fifteen to twenty-five new design solutions were implemented into production annually. The factory specialized in the production of pumps of large dimensions, weight and efficiency.

The factory supplied its products to almost all branches of industry and the national economy, constantly expanding its production, especially for the needs of chemicals and energy.

A very serious technical and production achievement was mastering the production of probably the most technologically difficult diesel pumps supplying power units of 125 and 200 megawatts. A foreign license was purchased for two types of main feed pumps and one initial pump. At the same time, work began on mastering the production of feed pumps of our own design.

Technological advancement made it possible to increase the share of production from group "A" - production
of an investment nature. In year 1965 the production of group "A" was 59,1 percent, in 1968 — 65 percent, and 1970 — 80 percent.

In addition to the traditional recipients of pumps, such as the sugar industry and municipal services, the Warszawska Fabryka Pomp began to supply other rapidly developing branches of the national economy, such as energy, chemicals, heavy industry and agriculture. The design and production of large cooling water pumps, necessary for large energy plants such as Turów, Konin, Łagisza, Halemba, Siersza, Pątnów and others, was developed.

These pumps are:

1. Vertical diagonal pump 120D40 for the cooling circuit of the power unit with a power of 200 megawatts, capacity of 13 cubic meters per hour, height lifting 22 meters of water column, rotational speed of 490 rpm and engine power powerplant - one thousand kilowatts.

Pump 120D40.

2. Vertical diagonal pump 140D40 for the cooling circuit of the 125 megawatt block.
Productivity - 17 cubic meters per hour. Lifting height - 500 meters of water column. Rotational speed - 490 revolutions per minute. Engine power - 1250 kilowatts.

3. Vertical propeller pump PR75R (180P20) with adjustable capacity by changing angle of the rotor blades. Productivity – 28 cubic meters per hour. Lifting height - 350 meters of water column. Rotation speed - 8,6 revolutions per minute. Engine power - one thousand kilowatts. Weight of the unit with engine - 365 kilograms.

At that time, vertical multistage condensate pumps were already being produced. In order to constantly improve the technical level of manufactured pumps, large-scale studies and research were carried out at the Warsaw Pump Factory.

Throughout the entire period of the plant's existence, the design office was the creator of almost all modern pump designs. Here, the structures of technically complex, high-performance diagonal and propeller pumps for cooling water of turbine condensers, primary condensate pumps, diesel feed pumps, hot water pumps (up to 250 degrees Celsius), high-performance double-stream pumps, etc. were created.

Thanks to, among other things, the creative activity of the design office, the range of pumps manufactured at WFP has been so enriched that our plant has become a leading manufacturer in Europe. In many cases, this allowed us to eliminate the import of technically complex pumps and export them.

For example, the current needs of the domestic energy sector are covered almost exclusively by pumps produced by WFP, which is a great progress compared to 50s, in which the main pumps for the energy sector were imported.

W 60s and 70s Due to the construction of a new plant in Żerań, there was a systematic and dynamic development of the design office, which constantly expanded the scope of its activities. In addition to developing pump designs, research work necessary for the development of the product range and design modernization was intensified.

The basic management staff of the design office in the new plant are the previously mentioned students and collaborators of Eng. Szczepan Łazarkiewicz. They worthily continued the work of the Great Constructor.

The main builders of the WFP, starting with nationalization in 1950

The main builders of the WFP, starting with nationalization in 1950

The year 1968. The sixth anniversary - this time the sixtieth anniversary of the plant - was celebrated was solemnly at the academy on the National Day of July 22, 1968. The Academy took place at the "Komedia" theater before a funny play purchased for the crew.

The Warsaw Pump Factory is moving forward to the next anniversary and will continue to move forward,
but it cannot also forget that it grew out of tradition and the work of now disappearing generations of people.

On the left, Barbara Rosicka, senior economist, was the only woman at WFP who served as chairwoman of the Works Council. Inside, Kazimierz Orlik, who had worked at WFP for 28 years, became involved with the quality control department. On the right, Henryk Monarski (Mondszajn) retired at the age of 77.

 

Energy savings in pump systems due to changes in required parameters.

2014-10-280

1. INTRODUCTION.

Many water pumping stations, especially those supplying water to large cities, built in the 1980s and earlier, are designed for capacities that significantly exceed current demand. As a result, among other things, they work inefficiently in terms of energy.

Significant changes in the method of operation also apply to power units built at that time. Initially, these units operated mainly at full load, but now they often operate with limited power, which makes an energy-efficient way of regulating pump parameters, especially pumps feeding boilers, with the highest power consumption, becoming important.

Adjusting the parameters of the pumping station or individual pumps selected for parameters and operating conditions other than those currently required is a significant source of potential energy savings.

2. METHODOLOGY.

It can be said that in every pump system designed and implemented some time ago, energy savings can be achieved by taking specific actions, which, however, requires certain investment outlays. Obtaining any savings is a relatively simple task, but the challenge is to choose the optimal path to modernize the system that will allow you to obtain the most favorable technical and economic indicators, such as the payback time or the internal rate of return. This requires specialized knowledge of pumps and pumping systems and the adoption of a specific methodology. Although tips on how to properly prepare for the modernization of a pumping system can be found in the literature, among others: [1,2], in practice there are examples of ill-considered actions, as a result of which significant investments do not bring the effects that could be achieved if more appropriate solutions were used.

The Powen-Wafapomp SA Group is a manufacturer of many pumps operating in the above-mentioned pumping systems that currently require modernization. Using knowledge of pumping technology and detailed technical information about its products, the company has developed a methodology allowing for energy optimization of pumping systems. The first step is an initial audit aimed at a rough assessment of the system's condition in terms of energy and estimating the effects that can be achieved. To carry it out, measuring instruments existing at the facility and an interview with the staff are usually sufficient. As a result, it is possible to roughly estimate how the efficiency of the pump units compares to the expected level and to assess whether it is worth investing further funds in optimizing the system, i.e. whether there is a potential to obtain favorable payback periods for projects aimed at saving the amount of energy used to drive the pumps.

If the initial audit indicates the advisability of further actions, they usually involve carrying out more precise measurements and analyzing their results, which allows for identifying the reasons for reduced efficiency. The most common reasons are deteriorated technical condition due to wear of pump units, incorrect selection of pumps for the system or ineffective method of parameter regulation. Only the formulation of such a diagnosis allows us to propose appropriate directions for modernization. It is advisable to select several alternative ways of modernizing the system and perform calculations for them, including estimating the possible energy effects for each variant and energy indicators (IRR, NPV), which allows for the selection of the optimal solution.

It is worth emphasizing here that modernization consisting in replacing the pump unit with a newer one with higher efficiency without prior analysis usually brings some energy benefits, but is not always an optimal method. This is because replacing the entire pump unit requires significant investment outlays. It is often not taken into account that a similar effect can be achieved by properly renovating the existing pump unit, which allows for energy efficiency similar to the initial one. Unfortunately, pump renovations in practice are often carried out with the aim of obtaining the so-called motor efficiency without restoring energy efficiency. Moreover, if the parameters of the new pump unit are incorrectly defined (e.g. as an uncritical duplication of the parameters of the previously existing unit), the new pump, despite high efficiency at the optimal point, may achieve much lower efficiency at the operating point because it is far from the optimal one.

In many cases, good results can be achieved by adapting existing pumps to current needs, which significantly reduces the required financial outlays.

Several examples of modernization of pump systems planned based on the described methodology are discussed below.

3. EXAMPLES OF MODERNIZATION OF PUMPING SYSTEMS TO REDUCE ENERGY CONSUMPTION.

3.1. Treated water pump.

The operation of the pumping station located at the water treatment plant located at the shore intake was analyzed. The purpose of the pumping station is to transfer treated water to a reservoir located on a hill from which the city of several hundred thousand inhabitants is gravity-fed. This system was designed in the 72s with a capacity of several thousand cubic meters per hour. The geometric height difference between the pumping station and the reservoir is approximately 1400 m, and pumping is carried out through a pipeline with a diameter of 1000 mm. In the design assumptions, several pumps were planned to operate in parallel to obtain the required efficiency. The capacity was to be regulated by turning on and off the appropriate number of pumps. Currently, due to the decrease in water demand, there are periods when the operation of one pump with a capacity slightly exceeding XNUMX mXNUMX is sufficient.3/h. However, turning off all pumps except one was an insufficient way to reduce efficiency due to the fact that the pumps were selected for parallel operation and their lifting height was selected taking into account flow losses through the pipeline resulting from the operation of several pumps. As a result, the pumps were selected for a lifting height of 88 m. When operating one pump, losses in the pipeline are much lower, as a result of which a single pump operates with an efficiency much higher than the nominal one. This not only reduces efficiency, but also overloads the engine. As a result, throttling was necessary to limit flow and power consumption. Pump parameters were measured at the workplace, which showed that the pump, which has been in operation for approximately thirty years (operating from the beginning without renovation), currently has energy efficiency reduced by approximately 10% due to wear. Since a significant potential for savings was found, the pump was subjected to more precise measurements at the factory testing station of the POWEN-WAFAPOMP SA Group. Based on their results, the direction of modernization was proposed. In this case, it was considered to replace the pump with a new one, better suited to current requirements, and, as an alternative, to renovate the existing pump combined with reducing the impeller diameter. Based on the analysis, the second variant was chosen as it allows for energy effects similar to purchasing a new pump at much lower costs. After renovating the pump and installing an impeller with an appropriately selected diameter, the pump efficiency improved and the need for throttling was eliminated, which resulted in a reduction in power consumption from 340 to approximately 220 kW, and therefore savings of 120 kW. This is an example illustrating the possibility of achieving significant energy effects with low investment outlays.

3.2. Diagonal pump on the shore intake.

The shore intake is equipped with four diagonal pumps type 80D25-4 with 1000 kW engines. The nominal parameters of the pumps are Q = 5760 m3/h, H = 41 m, n = 740 rpm. The purpose of the pumps is to supply water to the raw water tank at the treatment plant located approximately 2 km from the intake.

The entire system was designed for a capacity of over 10 m0003/h, which was ensured by the simultaneous operation of two pumps. Currently, due to reduced demand, the intake capacity varies in the range of 600 - 2500 m3/h, most often around 1500 m3/h. With such a limited flow, losses in a pipeline designed for a much larger capacity are insignificant, as a result of which the system characteristics are flat and the head results mainly from the geometric difference in levels between the intake and the reservoir. Measurements were made and it was found that in the considered capacity range 600 - 2500 m3/h, the corresponding change in lifting height is in the range of 25 - 27 m.

In order to adapt the pumps to current requirements, a frequency converter was used to regulate the rotational speed. This method of regulation, however, was not fully effective because, as is known from theory, with flat characteristics of the system (when the lifting height must be maintained approximately constant), a significant reduction in efficiency causes the pump to leave the area of ​​favorable efficiency. In this case, obtaining a capacity of 1500 mXNUMX from the pumps with the nominal parameters given above3/h at 26 m of lifting required limiting the pump speed to approx. 540 rpm. A more detailed analysis showed that the pump operates with an efficiency of only about 42% and a power consumption of 290 kW. The low efficiency of the system in this case resulted primarily from the significant oversizing of the pump, which causes it to operate far from the optimal point despite being regulated by changing the speed. Also important was the significant underload of the electric motor and the poor technical condition of the pump and engine, which had been in operation for several decades. As a result of the analysis of possible solutions, it was found that in this case it is advisable to replace the pump unit with a new one, consisting of a pump selected for the current performance range and an engine with an appropriately lower power. The appropriate pump for this application is the 40D30 pump operating at a speed adjustable in the range of 1260 - 1860 rpm, achieving efficiency above 80% in most of the required capacity range. In order to reduce the required investment outlays to a minimum, the POWEN-WAFAPOMP SA Group offered the delivery of a pump in a special version 80/40D30, consisting of the hydraulic part of the 40D30 pump (impeller and guide) with the required parameters connected to the outlet part of the 80D pump (outlet elbow). This made it possible to install a new, smaller pump on the existing site without the need for any changes to the foundations or piping system. Power consumption of the new pump unit at 1500 m3/h is at the level of 140 kW, which means a saving of 150 kW compared to the existing state.

This is an example showing that the use of a frequency converter alone, without a comprehensive analysis of the pump system, does not provide full results. This example also shows the possibility of reducing modernization costs as a result of the manufacturer's flexible and individual approach, which adapted the pump unit to the existing station.

3.3. Boiler feeding pump in a heat and power plant.

The analysis covered pumps type 15Z28x7V2 manufactured by the POWEN-WAFAPOMP SA Group, with rated parameters Q = 275 m3/h, H = 1820 m, n = 4660 rpm feeding the steam boiler in the heat and power plant. These pumps are driven by 2 MW engines with a rotational speed of 2980 rpm. The drive is carried out by a gear transmission that increases the revolutions and a hydrokinetic clutch that regulates the rotational speed.

Based on measurements of parameters archived in the recording system, the efficiency of the pump unit was estimated, which ranged from 45% for 150 m3/h up to 58% at 250 m3/ h.

The analysis showed that the reasons for such low efficiency are as follows:

a) Deteriorated technical condition of pumps and other elements of the pumping unit that have been in operation since the 70s.

b) Pump oversizing. As shown by the analysis of historical data, the pumps never operate at the nominal parameters specified above, but most of the time they operate at a capacity below 200 mXNUMX.3/h. Since the characteristics of the system are flat (a specific, high feed water pressure is required), the pump is selected for a capacity of 275 m3/h in the range below 200 m3/h operates with reduced efficiency even when controlled by changing the rotational speed.

c) Incorrect way of adjusting the speed. The efficiency of the torque converter decreases as the speed on the regulated side decreases (i.e. as slip increases). Speed ​​regulation using a torque converter was appropriate when the block was intended to operate at full power or with its slight reduction, because then the depth of speed regulation is small and the resulting losses are insignificant. However, when the block operates most of the time with significantly reduced power, the losses on the torque converter are severe.

Several variants of modernization of the pump unit were taken into account, including:

– replacing the drive via a torque converter with a drive via a frequency converter without changing the pump

– replacement of the torque converter with a new one with an appropriately selected gear ratio in order to eliminate excess parameters and at the same time overhaul the pump

– use of a frequency converter for the drive with simultaneous renovation of the pump combined with its reconstruction from 7 to 10 degrees. This reconstruction is aimed at obtaining the required parameters at a lower rotational speed, which shifts the optimum efficiency towards lower capacities, at which the pump operates most often.

The latter method turned out to be optimal as a result of the analysis. It allows for energy savings for driving the pump by approximately 30% compared to the current state, assuming the annual load distribution of the unit resulting from historical data. This method showed the most favorable IRR and NPV indicators.

This example illustrates that in-depth analysis is required to obtain the best results. In this case, better results than the commonly used solution involving the use of a frequency converter can be achieved by combining this solution with a properly planned modification of the pump and its renovation.

4. SUMMARY.

In order to obtain optimal results in terms of energy savings for driving pumps, it is advisable to analyze the pump system according to an appropriate methodology by people or companies with knowledge and experience in the field of pumping technology.

Obvious and expensive solutions, such as replacing the pump unit with a new one or using a frequency converter, usually give results, but are not always optimal. We should not forget about the need to properly select the pump parameters for the system, which can be achieved by its modernization, or the fact that significant reserves in terms of energy consumption lie in proper renovation management, because often low efficiency of the system results from the wear of the pump and the lack of proper maintenance. renovations. Practical experience collected during measurements and analyzes of pumping systems indicate that the current efficiencies of pumping units are significantly reduced compared to the initial values. This results either from the complete omission of general overhauls or from performing them incorrectly, e.g. using spare parts other than original ones. This factor is sometimes overlooked when making decisions aimed at achieving energy savings. Decisions are often made about investments requiring significant outlays, forgetting that similar energy effects can be achieved with much lower costs for properly carried out renovation (e.g. commissioned by the manufacturer).

The selection of the optimal course of action, as mentioned, requires a comprehensive analysis of the problem and the consideration of multidirectional actions, not limited to those that seem obvious, but which, however, do not always turn out to be optimal as a result of a professional assessment. Professionally prepared modernization of the pumping system in many cases allows for energy savings of several dozen percent and favorable payback periods.

In terms of analyzes of pump systems and the implementation of activities planned on their basis, it is advisable to cooperate with a pump manufacturer who has the required technical information about them and the necessary knowledge and experience.

Dr. Eng. Grzegorz Pakula

LITERATURE:

[1] Jędral W., Energy efficiency of pumps and pumping installations, KAPE, Warsaw, 2007

[2] Plutecki J., Assessment of the condition, directions and effects of modernization of pumping systems, Pumps Pompownie, No. 1 (148), April 2013, pp. 23-26.

Modern drainage systems for open-pit mines.

2014-10-210

The drainage system of open-pit mines usually consists of two subsystems. Wells are drilled around the open-pit mine area and deep-well pumps are installed in them. This is the so-called a protective barrier whose task is to lower the level of groundwater in the entire area so that these waters do not appear in the mine excavation. This is the so-called deep drainage system, which will not be discussed in this paper. In addition, there is a surface drainage system in the mine excavation, the task of which is to drain rainwater and residual groundwater from the open pit excavation, which bypasses the barrier of deep-well pumps and leaks from the rock mass into the open pit. This water is collected from the open pit area through a system of drainage ditches and directed to the pumping station tanks. These pumping stations are usually located on permanent open pit shelves. Excess rainwater, e.g. during heavy rainfall, is collected in the lowest point of the open pit, from where, after the rainfall stops, it is gradually pumped to the main pumping station tanks.

These pumping stations can be equipped with traditional stationary pumps. However, this solution causes some operational difficulties in open pit conditions. Firstly, the situation in the open pit is variable, because due to progress in exploitation and the type of "moving" of the workings, the location of the pumping station must change. In the case of traditional pumping stations, this is associated with significant costs. The second problem is the instability of the open pit slopes, which tend to slide under the influence of heavy rainfall or increased groundwater outflow, threatening to bury the pumping station.

fig 1

Fig.1. Diagram of a drainage system with stationary and submersible pumps.

Due to the above-mentioned inconveniences related to stationary pumps, a surface drainage system for open pits was developed based on submersible pumps. In addition to lower sensitivity to the threat of flooding, submersible pumping stations have another valuable advantage in the form of a smaller footprint compared to stationary pumps. It is important to realize that every square meter of land in an open pit is valuable because it requires the removal of many tons of overburden. Generally, the cost of building submersible pumping stations is lower compared to pumping stations equipped with stationary pumps. In addition, submersible pumps do not require any maintenance, they do not require venting or priming before starting, which allows the construction of a remotely controlled drainage system.

Pump lifting heights required in surface drainage systems of open-pit mines usually do not exceed 200 m because the exploitation of deeper open-pit mines is unprofitable. Single-stage submersible pumps can be used up to a lifting height of 100 m. A series of OZ pumps with an unusual design has been developed especially for this purpose. A common design solution for single-stage submersible pumps involves the use of a collecting spiral and a discharge port directed to the side. A different system is used in OZ pumps. The drive motor is located below the pump, and the inlet to the impeller is from the drive side through a ribbed slot located around the pump circumference. A vane guide is used, and the pump discharge port is directed vertically upwards.

This structural arrangement has the following advantages:
a) The engine is effectively cooled because it cannot emerge.
b) The pump does not suck heavily contaminated water from the bottom of the tank, but partially clarified liquid from a higher layer
c) The shaft seal, consisting of two mechanical seals working in the oil chamber, is not exposed to discharge pressure but only to hydrostatic pressure, which reduces the risk of leakage
d) The centrifugal vane guide eliminates the occurrence of significant radial force when operating beyond the nominal point, which in pumps with a discharge spiral is a source of vibrations at the shaft end, which favors seal failure.

OZ pumps can be installed either by placing them on the bottom of the tank or by hanging them on the discharge stub, which is facilitated by the symmetrical, axial position of the stub. Due to the fact that surface water in an open-pit mine may contain significant amounts of solid pollutants (sand, etc.), OZ pumps are designed for rotational speeds of 1500 rpm, as higher speeds would favor rapid wear due to erosion.

fig 2

Fig. 2. Single-stage submersible pump, OZ type.

The range of parameters of OZ pumps includes a capacity of up to 1600 m3/h and a lifting height of up to 100 m, which fully covers the demand occurring in typical open-pit mines. For deeper open pits, where the required lifting height exceeds 100 m, multi-stage submersible pumps OWZ have been developed, operating in a similar construction system, i.e. the pump is installed vertically above the engine. These pumps, unlike typical deep-well pumps, are designed to operate in contaminated water and do not contain construction nodes sensitive to contamination, such as bearings lubricated with the pumped liquid. The capacity range of OWZ pumps reaches up to 600 m3/h and lifting heights up to 280 m.

fig 3

Fig. 3. Multistage submersible pumps type OWZ.

fig 4

 

As mentioned, at the lowest point of the open pit, water from heavy rainfall may accumulate, which cannot be absorbed by drainage ditches during heavy rainfall. The water collected in this place must be pumped to the pumping station tanks located slightly above, on the slopes. Locating any pumping station in a flood area is difficult, so the best solution is to use pumps floating on the surface on pontoons and pumping water through flexible conduits. This method of installing pumps does not require significant investment outlays and allows pumping in difficult conditions with variable water levels in the floodplain.

fig 5

Fig. 4. Pontoon with an ON pump.

In summary, it should be stated that the use of submersible pumps instead of traditional stationary pumps in a surface drainage system brings the following benefits:
a) Lower investment outlays for the construction of a pumping station, including lower costs of moving it within the open pit as a result of the progress of mining works.
b) Greater safety of system operation because submersible pumps are not sensitive to flooding.
c) No problems with suction, the pumping station can operate in a much larger range of changes in the liquid level.
d) No maintenance requirements, possibility of automation and remote control.

Dr. Eng. Grzegorz Pakula

 

Mine drainage costs.

2014-10-140

In order to keep deep mines in operation, they require drainage, i.e. pumping the water flowing into the underground workings to the surface. This water comes both from the natural penetration of water present in the rock mass and from technological processes carried out in the mine underground, such as spraying water near the operating combine harvester to reduce dust. If drainage were stopped, after some time the mine would be filled with water to the level corresponding to the groundwater table. In addition to active mines, there are also mines in which mining has ceased, often partially or completely flooded. In order to ensure the safety of neighboring active mines, drainage of closed mines must continue,

Incurring drainage costs is therefore inevitable to enable safe mine operation. The point is to ensure that the costs of deodorization do not exceed the technically justified level, which unfortunately is not always the case. The level of dewatering costs is important for the financial results of mining companies. In addition to the economic aspect, the general social dimension also has an ecological aspect. The total power used for mine drainage is so high that it can be concluded that at least one power unit in the power plant works exclusively for this purpose. As we know, the production of electricity inevitably involves environmental threats in the form of, among others, CO emissions2 and waste from fuel combustion that requires storage. The power used to drain mines is of such a magnitude that it constitutes a serious environmental threat and therefore constitutes a social problem that goes beyond mining.

Power required for mine drainage depends on two main parameters: the amount of water per unit of time that should be pumped out, which translates into the required pump efficiency, and the depth of the mine, which affects the so-called pump lifting height. The specific weight of the pumped water also has a significant impact on the power, depending on, among others, on the degree of its salinity and pollution. Typical parameters of a mining main drainage pump are a capacity of 500 mXNUMX3/h and a lifting height of 700 m. With such parameters, for a typical degree of water pollution, the minimum power required to drive the pump is approximately 1 MW. This is the theoretical power that an ideal pump operating without any losses would draw. It results from the laws of physics, because the energy needed to raise water of a given mass to a given height is fixed. It is impossible to go below this power consumption using any technical solutions. In practice, pumps consume power higher than theoretically required, because real machines always work not according to the ideal theoretical model, but with certain losses resulting, among others, from the occurrence of friction and other inevitable physical phenomena.

The parameter that characterizes the pump in this respect is its so-called energy efficiency, which indicates what percentage of the total power consumed by the pump is necessary from a theoretical point of view. The rest of the power is lost in the pump. For example, the energy efficiency of modern pumps with the parameters specified above is at the level of 80%. This means that if the theoretical power consumption level is 1 MW, the pump consumes 1.25 MW (1 MW is 80% of 1.25 MW). We are talking about the efficiency of the new machine, because the efficiency of the pump inevitably decreases during operation. This is due, among other things, to the mentioned contamination of mine waters with salts and solids causing intense corrosion and mechanical wear of the main pump components. The energy efficiency of a heavily exploited pump may drop to 50-60%, which for the parameters given in the above example would mean an increase in consumption to 1.66 - 2 MW. In practice, for a single pump, no increase in power consumption is observed during wear, which is due to the fact that the pump loses efficiency and pumps less water than a new pump, and therefore, despite deteriorating efficiency, it does not show a dramatic increase in power consumption. However, it should be remembered that the cost of pumping is not influenced by power consumption, but by its consumption resulting from multiplying power consumption by the pump operation time. A worn-out pump must work longer to pump out the same amount of water as a new pump, and therefore its energy consumption increases to an extent corresponding to the decrease in efficiency.

The above facts lead to the conclusion that the level of mine drainage costs is mainly determined by the renovation policy. The cost of drainage, roughly speaking, consists of two main elements: initial investment outlays and operating costs, which in turn include electricity costs, maintenance costs and renovation costs. It can be shown that the economic effect depends primarily on electricity consumption. The cost of purchasing a pump unit with parameters similar to those given above is in the order of several hundred thousand zlotys. The cost of operating the pump approximately corresponds to the cost of maintaining one full-time job, and therefore amounts to several dozen thousand per year. The main drainage pump usually runs about 10 hours a day, i.e. 3650 hours a year. If its power consumption is 1.25 MW and the cost of 1 kWh is assumed to be 30 groszy, the cost of energy consumed by the pump per year is PLN 1,37 million. This is a value for a modern pump in very good technical condition with an efficiency of 80%. However, if the pump efficiency is reduced to 60%, the annual cost of energy consumption increases to PLN 1.82 million, i.e. by PLN 450. zloty. The increase in the cost of energy consumed by the pump is therefore much greater than the cost of maintenance and is similar to the cost of purchasing a new pump unit.

As can be seen from the proportion of the pump purchase cost and the cost of energy consumption, the impact of investment outlays is not decisive. When purchasing a new pump, you should, of course, make sure that its energy efficiency is at a sufficiently high level, which is usually the case with serious manufacturers of main drainage pumps. In addition to initial efficiency, the rate at which efficiency decreases during operation should be taken into account. This rate depends on the design of the pump, the quality of its workmanship and the materials used and may vary significantly for different manufacturers.

The importance of proper maintenance management for mine drainage costs is increased by the fact that Polish mines have been equipped with pumping stations for a long time, and new investments are relatively rare. In practice, most pumps are used that have been operating for many years, often completely depreciated. In this situation, the costs of drainage are practically determined by two main factors: the cost of renovation and the cost of energy consumed. The cost of renovating the main drainage pump is, depending on the scope, a certain percentage of the value of the new pump and ranges from several dozen to several hundred thousand zlotys. In each case, however, it is many times lower than the cost of energy consumption. The cost of renovation affects the energy efficiency of the pump obtained after renovation. When deciding to order renovation, you should not only consider the price of this service, but first of all take into account the effect in the form of energy efficiency obtained. It may happen that saving several dozen thousand zlotys on renovation costs results in several hundred thousand losses in electricity costs. Therefore, the criterion for selecting a renovation contractor cannot be only the price, but also the energy parameters obtained after the renovation. When ordering a renovation, the requirement to check the energy efficiency at an appropriate measuring station should be mandatory.

Understanding the above facts and implementing them in practice is not only in the interest of mines but has also been shown to protect the environment.

Dr. Eng. Grzegorz Pakuła

 

"The fifth decade" - Józef Raczko

2014-10-090

"The Fifth Decade"

year 1950 brought us the nationalization of the plant. This fact changed the entire system of both organizational and interpersonal relations.

Zakłady Mechaniczne Eng. Stefan Twardowski received the Temporary State Compulsory Management Board under the supervision of the Capital Local Industry Board. Shortly thereafter, they changed their name to Warsaw Pump Factory - State Enterprise.
The Ambrożewicz Foundry came under state management 1949 year, and Dyjasiński's foundry - w 1951. IN 1955 In the same year, both foundries were taken over by the Warszawska Fabryka Pomp and became part of it.

The main problem after nationalization was wage issues. From the beginning of the plant
we worked on a day-work basis, and now we were to switch to piecework. Longer discussions on this subject with the then first state director of the plant, Eng. Mazurkiewicz (appointed director, came from the sugar industry) allowed us to establish that the first piece rate would be based on 80 percent of the work time that we had previously given on the daily wage cards. It was different. The technology unit was headed by a former theater employee who moved or raised curtains on stage. We had thousands of misunderstandings with him. It also happened that an employee rushed him and he escaped from the office window. And it was called a calculator!

During this period, interpersonal relations were very bad. The number of machines began to increase. A large planing machine, long "Poręba" lathes, a new boring machine, a new saw, and a new drill allowed for a significant increase in production and pump dimensions. The issue of enlarging, or rather extending, the production building became a problem for the new administration. So that a new assembly hall would be built behind the testing station, and the existing hall would be a processing hall.

Extending the hall would facilitate the installation of deep-well pumps consisting of twelve, fifteen or more shafts. This assembly required a 30-40 meter long stand. It also happened that the pump occupied the length of the yard and almost the entire building. The conditions for extending the hall were in place and it was done.

For the first time after the nationalization of our plant May 1 was celebrated in 1951 year. There was no academy, but there was a mass gathering and a march to Śródmieście for a procession. On that day, I received a Diploma of Appreciation for thirty-one years of work at the plant with a seal with the inscription: "Zakłady Mechaniczne Eng. Stefan Twardowski. State Board.” It was signed by the chairman of the Works Council, Stanisław Chłopecki, and the party secretary, Władysław Małecki.
Next to the stamp: "For the director" there was an illegible signature.

The diploma was handmade, ornately drawn, beautifully calligraphed, with an elaborate dust jacket around it. Two symbols of our production are drawn in the upper corners: two different small centrifugal pumps. The diploma was the work of Mr. Stefan Gryczmański - an employee of the design office. It was the first diploma issued after nationalization. Before nationalization, diplomas were not issued. It is one of my most pleasant souvenirs.

It is appropriate to recall the birth of the initiative to reward employees for good work, for leadership, for exemplary work, for invention, etc.

After the plant was nationalized on 18.VIII. 1950 I received a certificate from the former owner of the plant - engineer Twardowski. Here is its full text:

Ob. Raczko Józef started working in our plants as a lathe apprentice on January 9.01.1920, XNUMX.
After completing 3 years of practice, he works as a turner on precision works to this day; he is a contractor of first-class value both in terms of workmanship and the shortest processing time of the machine part given to him. We would like Mr. Raczko to continue working in our plants, setting an example of how to do his job.

At the time of nationalization, the foreman of the entire workshop was a man working from... 1911 year locksmith Wincenty Piotrowski. Unfortunately, he had been suffering from diabetes for many years, which rapidly deteriorated his health so much that he passed away shortly after nationalization.

It was then that he was appointed head of the department engineer Jerzy Kabała. He was the chief mechanic at Grochowska Street and the head of the entire machining and assembly department. He liked a pompous profile and chose solid people. He was putting out a lot of good pumps. He carried out his plans, even though the conditions were difficult, even very difficult. He deserved the plant. He was the initiator of appointing two employees subordinate to him as foremen. One was a locksmith Arsenius Shoemakers, who returned from the war, and the second one was me. It's been a year 1955. IN 1957 I became a senior master. After these changes, the department entered the right organizational path.

On the left, engineer Jerzy Kobała, who controlled the chaos that broke out in the factory after nationalization. On the right, Arseniusz Szewcow became the champion at Grochowska in 1953.

The plant, although in very modest conditions, produced increasingly new and larger pumps. After humble pre-war beginnings in 1954 year was undertaken on a larger scale production of diagonal pumps. The first of them, types D12G and D17G with a capacity of 210 and 300 cubic meters per hour, were made for the Provincial Water and Sewerage Company in Katowice and intended for extracting water from deep drilled wells. This happened during a period of acute water shortage in Upper Silesia.

As engineer Łazarkiewicz said, in the same year an order was placed for the first high-performance diagonal pumps for power plants, intended for cooling condensates. These were D40/80 pumps with a capacity of four thousand cubic meters per hour for the power plant in Ostrołęka. They were one of the first pumps for the power industry, the production of which was significantly developed in subsequent years in terms of quantity and product range.

It was designed and manufactured to transport a mixture of potatoes and water new type of pump N22/20 TR. Since then, i.e. a year ago 1955, the potato industry stood next to the sugar industry, it is the main recipient of small and medium-sized pumps.

Arseniusz Shevtsov traveled the battle route from Lenino to Berlin. It led through Warsaw.

In year 1956 production of single- and multi-stage circulation pumps for water with temperatures up to 150 degrees Celsius for central heating networks began.

Due to the constantly increasing demand for sewage pumps throughout the year 1957 production of vertical axis sewage pumps began on a larger scale. This arrangement, beneficial for many reasons, was widely accepted so that in the following years there was a need to develop a new series of these pumps with a capacity of up to 3600 cubic meters per hour. IN 1958 The first orders for pumps were received as part of complete deliveries for sugar factories for export. First for the Soviet Union and Iran, and in the following years for many other countries. The Ministry of Agricultural and Food Industry, under which our plant worked, decided that the demand for pumps for the food industry, especially the sugar industry, is so great that our plant should produce only for the needs of this industry, and if the heavy industry needs more pumps for other branches of the economy, let him build a new plant.

This concept was unacceptable to us.

In year 1957 the current POP secretary, Comrade Stanisław Grossinger, and the plant's management took a correct and decisive position, believing that: "The plant should continue to be maintained assortment of sugar pumps and others from the food industry profile and go further on the comprehensive production of new designs for various purposes and requirements, with larger dimensions and for a wider range of recipients, including export. There's a bet predestined to be the most modern pump production plant for country and for export, and one of the most modern in Europe, producing pumps based on its own documentation and highly specialized staff.

These words spoke and it was decided to establish a New Plant Construction Committee.

Comrade Helena was constantly invited to the Committee's meetings and was very helpful
Biernacka — a member of the POP executive in WFP, and at the same time a full-time employee of the Committee
Central Polish United Workers' Party.

The Committee began its work by preparing a memorandum to the government and party authorities containing a thorough justification for the need to build a new plant located in Warsaw, also due to the fact that the existing plant has construction and production staff with many years of experience in the field of pump construction. The committee worked in two directions: along the lines of the industrial administration to obtain the transfer of the plant from the Ministry of Agriculture and Food to the Ministry of Machinery, and along the party lines to obtain a new location for the factory in Warsaw.

Engineer Janusz Walczyński fought for a new factory headquarters, and in the 70s he struggled with problems during the construction of the Prophylactic and Recreation House in Złockie.

The Committee, especially in the initial period, had many problems with overcoming the position of the ministerial authorities, which was: a new factory, yes, but in Siedlce, Łapy or somewhere else, as long as not in Warsaw and not in Żerań. Despite opposition from the central authorities, the construction of the new plant was approved.

In year 1957 the company was taken over by the Ministry of Heavy Industry as part of the General Management of Machine Construction. Later - as part of the Union
Heavy Machinery Construction Industry, and finally - the Union of the Chemical Equipment Construction Industry "Chemak".

Organizational life at the plant expanded in line with the form adopted throughout the country.
There was a trade union and party organization. The Workers' Self-Government was established. I was a member
first Works Councils and took an active part in their work. I served for two terms
chairman of the local government body - the Workers' Council.
The year 1958. The plant called Warszawska Fabryka Pomp celebrated its fiftieth anniversary
existence. This is the factory's fifth anniversary in general, and the first one after nationalization.

For me, these were the last months before the 40th anniversary of my work
in this plant.

The anniversary celebration was organized no 15 August, as the date of creation says, but earlier - on an occasion National Day of July 22. An academy was organized in the common room of Polskie Zakłady Optyczne - a solemn and pleasant one. After the speech of the director, Eng. Józef Doliński, the first ceremony in the history of the plant of awarding state awards to distinguished, long-term employees took place.

For my professional and social achievements, I was awarded the Golden Cross of Merit by Deputy Minister Key from the State Council of the Polish People's Republic, as well as a statutory jubilee bonus (two months' salary) and an apartment from the resort's pool at Aleje Jerozolimskie 63/27. On that day, state decorations were also awarded to: engineer Szczepan Łazarkiewicz - Officer's Cross of the Order of Polonia Restituta for thirty-nine years of professional work and social activity, Comrade Edward Czerwiński - Officer's Cross of the Order of Polonia Restituta for thirty-nine years of professional work and social activity, Józef Krasnodębski - Badge of the Forerunner of Work for long-term and conscientious professional work, Leopold Andrusiewicz , former - Knight's Cross of the Order of Polonia Restituta for thirty-eight years professional and social work. On behalf of the recipients, I had the pleasure of expressing my thanks to the state and company authorities.

The design of a vertical pump for the Warsaw Zoo prepared in 1949 - still in the private Mechanical Works of Eng. Stefan Twardowski.

 

Adjusting pump parameters to the needs of the installation – part II.

2014-10-070

In the first part of the article it was stated that in many cases there is a need to correct pump parameters in order to better adapt them to the requirements of the pumping system.

In this regard, the following most frequently used possibilities exist (let us emphasize once again that we are talking about a one-time correction of pump parameters, and not about their continuous regulation, which was mentioned in the first part):

  1. Reduction of rotor diameter
  2. Changing the outlet angle of the blades
  3. Changing the number of steps
  4. Changing the rotational speed
  5. Replacing the pump with another one
  6. Modernization of the pump involving the use of a new flow system.

Re 1. This is a commonly used method of correcting (reducing) pump parameters, which can be used to a limited extent. The optimal operating point of the pump shifts in such a way that the efficiency decreases approximately in proportion to the impeller diameter and the head with its square. The reduction of the rotor diameter is accompanied by a certain decrease in efficiency, the greater the reduction. It can be assumed that the decrease in efficiency is not significant if the diameter reduction does not exceed 10% for pumps with vane guides and 20% for pumps with a spiral. With this method, without significant damage to efficiency, it is possible to correct parameters in the range of 90-100% of efficiency and 81-100% of lifting height for pumps with guides and 80-100% of efficiency and 64-100% of lifting height for pumps with a spiral. (These are approximate, average ranges for the entire pump population. Detailed data for individual pump types can be obtained from their manufacturers). Since the cost of reducing the diameter is not high, without complicated analyses, it can be assumed that this is the optimal method of correcting pump parameters in the limited range mentioned above.

Re2. The pump lifting height can be increased by several percent by "cutting" the blades from the passive side at the impeller outlet, which increases the outlet angle of the stream. This procedure does not have a significant impact on the pump's efficiency. The disadvantage of this method is that it must be performed using rather primitive metalworking methods, and in addition, thinning the blade at the outlet may shorten the life of the impeller in the long run when pumping media containing solids that "smooth" the outlet part of the blade.

Re 3. In multistage pumps, the head varies in proportion to the number of stages while maintaining the optimum performance. Therefore, if the correction of the parameters of a multistage pump is to involve a significant change in the lifting height at a fixed capacity, this is an appropriate method for this purpose. The pump can either be shortened completely by reducing the number of stages and using an appropriately shorter shaft and tie bolts, or its connection dimensions can be maintained by replacing the removed stages inside with sleeves guiding the liquid to the next stages. If the pump did not have the maximum allowable number of stages, it can be expanded to a larger number of stages, which of course requires the use of a new shaft and tie bolts.

Re 4. Changing the rotational speed is commonly used as a control method, but it can also be considered as a way to make a one-time correction of parameters. The parameters of the optimal operating point change so that the efficiency is proportional to the rotational speed, and the lifting height varies with the square of the rotational speed. What is important is that in a very wide range, changing the speed does not result in deterioration of efficiency, and as a result, the scope of applicability of this method is wider than in the case of reducing the rotor diameter. Technically, changing the rotational speed is easiest to achieve in the case of gear-driven pumps by changing its gear ratio. However, also in the case of pumps driven directly by the engine, this can be achieved by using a frequency converter, which in this case is not used for smooth speed regulation, but for a one-time change. The disadvantage of this solution is the cost of the transducer, although with the current tendency to drop the prices of these devices, this solution may prove advisable even for a one-time correction, especially for lower supply voltages. When analyzing such a solution, remember that additional energy losses occur in the inverter and in the motor operating at a lower frequency. The advantage is that further adjustments are possible if further changes to the required parameters are expected in the future. Changing the rotational speed upwards is only possible to the extent that it does not exceed the strength capabilities of the pump components due to the increase in pressure and power consumption. In each case, when changing the rotational speed, the pump manufacturer should be consulted, as such a change may cause movement problems (e.g. resonance when operating at a critical speed, problems with the load capacity of plain bearings, seal operation, etc.).

Ad. 5. Replacing the pump with a new one with different parameters that meet current requirements is an obvious, but usually expensive solution. For this reason, this solution is not usually used in cases that can be solved by other, cheaper methods. When making a decision, however, you should bear in mind the fact that purchasing a new pump is a long-term solution, as its operation with a properly conducted renovation policy will be possible for several dozen years. However, carrying out various types of treatments and modernizations on a pump that is largely worn out is a much shorter-term solution, as its technical condition (material fatigue, degeneration of fits after numerous regenerations, degree of corrosion and "washing out" of elements) may make it impossible to keep it in operation for a longer period of time. period. Therefore, due to, among others, on the reliability of operation and the cost of maintaining the pump in operation, the purchase of a new pump should be considered as a real alternative, especially when the required change in parameters is significant.

Re 6. Pump modernization consisting in maintaining the existing pump housing and designing a new flow system seems to be an interesting alternative to purchasing a new pump, as it allows obtaining hydraulic parameters corresponding to the changed needs using the elements of the existing pump and without the need to make changes to the structure at the workplace.

However, this method also has some weaknesses:

a)    If the pump bodies are to be retained, the scope of possible parameter corrections is limited. Flow rates (capacity related) at ports, inlets and outlets are subject to certain design limitations and cannot be varied too widely without compromising pump performance

b)    After a certain period of use, the body surfaces are corroded and washed out. This has little impact on the efficiency of a multi-stage pump with a high head, but has a significant negative impact on the efficiency of pumps with a high capacity in relation to the head, such as diagonal or double-jet pumps, since in this case flow losses (due to surface roughness) in the liquid discharge elements they constitute a significant percentage of the lifting height. Regeneration of these surfaces is difficult, and the use of coatings improving smoothness on highly degraded surfaces does not guarantee durability of their adhesion. As a result, the pump, even if it has a new, highly efficient flow system, loses its efficiency compared to the new pump.

c)    As mentioned when discussing point 5, the service life of such a modernized pump will be limited due to the wear of the components.

d)    Unlike a new but well-known pump on the market, whose parameters are known, the parameters obtained from a flow system designed from scratch for a specific case are subject to uncertainty. The methods of designing pump hydraulics are not fully precise and depend to some extent on the experience and intuition of the designer. Even the best designers of flow systems do not always "hit" the expected parameters on the first try.

e)    Modernization involving the design of a new flow system is not a cheap procedure. Apart from the costs of the project itself (which depend on how much an experienced designer values ​​his knowledge), it should be remembered that it requires modeling of the rotor and a set of vanes. The market cost of such modeling is several dozen thousand zlotys, which excludes the profitability of individually designing a flow system for a moderately priced pump. Taking into account the fact that, as mentioned above, designing a high-efficiency flow system with given parameters usually requires the preparation and testing of several versions, the modeling cost must be multiplied several times.

f)     Modeling a flow system takes up a significant volume, which means that the cost of its storage is significant. Therefore, there is a concern whether the modeling of a flow system designed for an individual case will be available years later when the need arises to replace the flow parts. This concern does not apply to mass-produced pumps.

g)    The formal and legal aspect should also be taken into account. Changing the flow system causes such significant changes in the pump parameters (pressure, axial forces, critical vibration speeds) that the pump cannot be operated after modernization on the basis of the documents on which it was put into operation. Modernization therefore requires the development of a new hazard analysis, declaration of compliance with standards, etc. in accordance with the requirements of the applicable machine safety assessment system. This increases the costs of modernization.

Having at our disposal the six basic methods of correcting pump parameters (and in some cases other, non-standard methods suitable for special circumstances), we are faced with the need to make a choice. This choice should result from a technical and economic analysis, which is an obvious statement, but difficult to implement in practice. A reliable analysis of this type is difficult in practice for both technical and economic reasons. From the technical side, it is impossible to fully predict the achieved effects, e.g. because it is not known in advance what efficiency the modernized pump will achieve (overly optimistic assumptions are often made in this respect), but also because the efficiencies of individual pumps of the same type according to with applicable standards may differ by several percent within permissible tolerances. From the economic point of view, there is no generally applicable methodology for assessing such cases.

Recently, the so-called LCC (life cycle cost) method, which is based on finding a solution that gives the lowest sum of investment costs and operating costs. This method is correct in principle, but its application also allows for some freedom (e.g. it is not specified in what period the operating costs should be taken into account - taking a shorter period prefers solutions with low investment outlays but giving lower effects in operation, and adopting a longer period vice versa; it is not clear what discount rate to use when taking into account costs in distant years, etc.). By appropriately manipulating the above-mentioned parameters, you can achieve different results. The author is aware of cases of extremely unreliable analyses, for example those in which the efficiency effects obtained as a result of modernization were related to the efficiency of an existing, worn-out pump reduced by several percent compared to a new pump, without taking into account that much better effects can be achieved could be obtained by replacing the worn-out pump with a new one, without any modernization. What's worse, verifying the obtained effects in practice is not easy, as it is common knowledge that measuring pump parameters in industrial conditions is often subject to serious errors (e.g. due to problems with precise performance measurement).

The above comments regarding the difficulties in practical selection of the optimal parameter correction method should not be understood in the sense that it is impossible. Certainly, as a result of a reliable analysis, e.g. conducted using the LCC method, it will be possible to eliminate correction methods that are completely unjustified in a given case. Difficulties may arise when assessing methods that are similar in terms of expected effects and differ by a few percent, as these differences may be within the margin of errors and approximations in the adopted assumptions.

In summary, in order to make progress in reducing the energy consumption of pumps, the following rules of conduct can be recommended:

1. You should start with a general audit of the pumping system, aimed at assessing whether there is any potential for savings, and if so, what.

2. Further attention should be focused on cases where the overall assessment shows that the pumps are not matched to the requirements, causing them to operate with reduced efficiency, and where there is a prospect of savings by adjusting the parameters

3. All possibilities should be considered (e.g. the six mentioned above) and none of them should be rejected a priori, but all of them should be assessed, e.g. using the LCC method

4. Good practice is that in order for the assessment to be objective, the company that evaluates and selects possible methods should not be interested in their implementation. If a company proposing a certain solution itself makes a technical and economic comparison with other variants, there is a fear that such an analysis is more of a marketing nature than a substantive one. Due to the fact that the assumptions made at the beginning of this type of analysis are always simplifying and, to some extent, intuitive, it is advisable to seek the opinion of another, independent institution that will verify the adopted assumptions.

5. When making a choice based on the results of the analysis, the investor should not use the conclusions uncritically, but should become familiar with the assumptions adopted as the basis for the analysis to make sure whether these assumptions are acceptable in a specific case. It is advisable to conduct a simulation calculation to check how changes in assumptions affect the results of the analysis.

6. As a result of the analyses, clearly inappropriate solutions should be rejected. If there is a group of solutions to choose from, which differ in effects only to a small extent (within the limits of the accuracy of the method), additional factors not usually taken into account in a typical technical and economic analysis can be taken into account, such as the reputation of the contractor or the risk of obtaining effects different from those expected.

Dr. Eng. Grzegorz Pakula