Typical structure analysis and engineering applica

2022-08-12
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Typical structure analysis and engineering application of submersible electric pump

Abstract: This paper briefly reviews the development of submersible electric pump at home and abroad, analyzes the typical structure of submersible electric pump at home and abroad, and introduces the structural types, types and engineering applications of submersible electric pump impellers abroad. Their varieties are numerous and their designs are novel, which can be used as a reference for domestic counterparts

key words: submersible electric pump; impeller; Structure; Analysis

introduction

submersible electric pump we believe is a special liquid conveying machine that combines pump and motor. As the name suggests, electromechanical integration works underwater. The utility model has the advantages of simple structure and convenient use. With the development of material science, sealing technology, control and protection technology and the improvement of cold and hot processing technology, submersible electric pumps have developed rapidly

in 1904, Byron Jackson company of the United States was the first company to successfully design and manufacture horizontal connected submersible pumps and submersible motors, which is the "ancestor" of modern submersible pumps. In 1928, the company invented the vertical submersible pump with direct connection, which is the original form of modern deep well submersible pump. It can be seen that the development of submersible electric pump has a history of more than 60 years

Sweden's sterery Flygt company successfully developed the world's first shallow water (or working face) submersible electric pump for water supply and drainage in 1948, fundamentally simplifying the pump type, reforming the drainage equipment of building foundation pits and mines, and soon achieved success in the world. In 1956, Flygt company produced submersible pumps for sewage discharge, which reduced the cost of sewage pump stations by about half. In addition, Flygt has also solved a series of difficult problems. Various special submersible pumps developed by Flygt can be used to pump abrasive, viscous and corrosive liquids containing solid particles. In recent years, Flygt has made great progress in the structure of pumps, and has developed four series: 2000 series for pumping abrasive liquids containing small particles, 3000 series for pumping civil and industrial wastewater, 5000 Series for pumping clean water, and 7000 series with large flow medium lift screw (axial flow)

by the 1960s, the United States, Britain, Germany, France, Finland, Japan and other countries also produced submersible electric pumps in large quantities. In particular, Japan (such as Hitachi, Hejian and other companies) has achieved the standardization and serialization of submersible electric pumps for construction equipment and engineering, and has made new achievements in structural design, material selection and automatic control

in 1958, China began to produce 7KW submersible electric pumps for working faces by Shanghai People's electric machinery factory, which opened the prelude to the production of submersible electric pumps in China. After more than 30 years of development, great achievements have been made at present. We have successively produced QY, QS, QX, QDX (single-phase) series of small submersible electric pumps. The annual output is about 1.5 million sets. Since the late 1980s, QW submersible sewage pump has been developed. QZ submersible axial flow pump and QH submersible mixed flow pump, etc. The annual output is about 80000 sets. The Institute of fluid machinery of Jiangsu University of technology has cooperated with Yangzhou Asia Pacific special water pump factory and other factories to systematically study the sewage submersible pump, and has undertaken three provincial and ministerial scientific research projects. The flow state in the pump, the structural type of the blade and the influence of geometric parameters on the pump characteristics were studied. Thus, he has mastered the design theories and methods of various non clogging sewage submersible pumps, accumulated rich experience in improving the performance of non clogging pumps, and has won the national, provincial and ministerial scientific and technological progress awards for four times. At the same time, he has also been listed as a national key promotion plan project of scientific and technological achievements by the national science and Technology Commission

1 typical structural analysis of submersible electric pumps at home and abroad

1.1 typical structural analysis of submersible electric pumps abroad

flygt company is the largest manufacturer of submersible electric pumps in the world, with the most complete series of submersible pumps. Its product design is novel, the component system is standardized, and the equipment is modern. Now choose one of the typical structures to analyze

Figure 1 shows the typical C pump structure of Flygt company, and the main features are as follows

(1) the cable of the motor must be able to withstand medium erosion, and the cable can be protected by flexible metal hose

(2) stator insulation grade F (155 ℃). According to the standard, an overload protector is installed in the motor stator

(3) when the power is above 9kw, there is a cooling system, and the back blade of the impeller makes the cooling water circulate around the stator chamber. An independent cooling system can also be used. The peripheral cooling jacket is not connected with the spiral case, and the cooling water is directly introduced from the outside. This cooling system is particularly effective when the temperature of the liquid pumped by the pump will rise or it is possible to run dry

(4) there is a double-layer mechanical seal between the motor and the hydraulic components. The filling speed of the current flexible packaging has not reached the speed of the common packaging box, so as to prevent the liquid from entering the motor cavity. Usually, the upper layer Jinan assaying first places the specimen horizontally on the support of the pendulum impact tester, which is graphite/tungsten carbide, and the lower layer tungsten carbide/tungsten carbide. In addition, besides tungsten carbide, aluminum oxide or silicon carbide can also be used as the sealing material

(5) different impeller structures are used according to different uses. The impeller shown in the figure has a large channel area, which can reduce the risk of blockage through large particles and entanglements

(6) a replaceable sealing ring is installed between the pump impeller and the pump body to keep the pump running at the best efficiency. Large pumps are equipped with two sets of sealing rings

Figure 1 submersible electric pump of Flygt company

Figure 2 QW sewage submersible system

1.2 typical structural analysis of domestic submersible pumps

Yangzhou Asia Pacific special water pump plant is the largest manufacturer of submersible electric pumps in China at present, and its products have been successfully applied to Shanghai Baosteel, Daqing oil field, Beijing new passenger station and other national large-scale key projects, replacing a large number of imported products. At the same time, its developed products have entered the international market

Figure 2 shows the typical structure of QW sewage submersible electric pump designed by the Institute of fluid machinery of Jiangsu University of technology and produced by Yangzhou Asia Pacific special water pump factory. Its main characteristics are as follows

(1) submersible pump with power above 30kW. A water leakage detection probe is set in the wiring chamber. When the cable breaks or water leaks for other reasons, the probe sends a signal and the control system protects the pump

(2) the stator of the motor adopts class F insulation (155 ℃), and is designed into a thin and long cylinder with an overheat load protector inside

(3) when the power is above 15kw, each pump is equipped with its own cooling system. The back blade of the impeller makes the water in the vortex chamber flow into the periphery of the stator chamber for circulating cooling, which can ensure the normal operation of the water pump at the lowest water level of the pool or when it is pumped dry

(4) a water leakage detector float switch is installed at the lower end of the motor cavity. When water enters the motor cavity, a signal is sent, and the control system protects the pump

(5) a double-layer mechanical seal is installed between the motor and the hydraulic parts to prevent the medium from leaking into the oil chamber. The scientific matching of the upper and lower layers can ensure the safe and reliable operation of the water pump. The sealing materials include silicon carbide, tungsten carbide, cemented carbide or super wear-resistant sealing pairs

(6) the oil chamber is equipped with electrode protection. When water enters the oil chamber, the electrode sends a signal, which is displayed by the control system to inform the management personnel of timely maintenance. At the same time, the control system closely monitors the leakage

(7) the impeller with unique design has a large channel, which can pass through large materials and fibers to reduce the risk of blockage and entanglement

(8) a replaceable sealing ring is installed between the pump impeller and the volute to keep the pump running with the best efficiency

2 types and engineering applications of foreign submersible electric pumps

with the continuous development of science and technology, many new structures and types of submersible electric pumps have appeared abroad. This paper only takes the submersible electric pump produced by Flygt company as an example. It has a wide variety and novel design, which can be used as a reference for domestic counterparts

Table 1 Types and engineering applications of submersible electric pumps of Flygt company

name impeller structure type impeller structure characteristics

engineering applications

b pump open or semi open impeller, made of anti-wear materials, with adjustable guide vanes and filters, is widely used in water supply and drainage or water jet of construction sites, caves, harbors, factories, ships, etc., and can pump liquid media containing abrasives such as clay, sand, gravel, drilling cuttings, etc

mobile structure, which can be started after being put into water, can meet the special requirements of large flow, high lift, limited space or explosive environment

c pump has non clogging closed channel impeller, which has good reliability and high efficiency. It is mainly used for pumping sewage and mud from urban pump stations and sewage treatment plants, pumping cooling water, waste water, corrosive media, etc. in industrial processes, and continuous drainage from construction sites and large factories. It is very suitable for pumping media containing long fibers and large solid particles

it is installed in a small and simple pump station, which can be hidden underground. The pump can be quickly and simply installed on the guide rail or rope and down to the pump pit. D-pump swirl impeller is widely used in construction sites, mines and industries to pump wastewater containing long fibers, clay, drilling cuttings, rock debris, sludge and corrosive media, and can meet the requirements of drainage in explosive environments. F pump has open impeller and S-type cutter, which has the functions of pumping, cutting and mixing. Good reliability and high efficiency. It is mainly used for pumping liquid manure in agriculture. It can break dry solids, straw and other long fiber substances. The helical impeller inlet can send the inhaled thick manure into the pump. There are four specifications

compact structure, installed on the guide rail in the manure tank, can also be installed in the storage tank, and can be used together with the submersible mixer. The open or closed impeller of G pump has several blades, which are mainly used for ground drainage in basements or other fields, and can also be used for irrigation. It can meet the needs of small flow and moderate head. It is suitable for pumping clean water or slightly polluted water. There are three specifications

compact structure, simple installation, just put the pump at the bottom of the pump pit. The open or closed channel impeller of H pump is mainly used for the manufacture of anti-wear materials in mines, construction sites, caves, tunnels, dams and other places to pump liquids containing abrasive particles such as drilling cuttings, sand, gravel, etc. the suction end adopts an adjustable rubber coating, which is conducive to operation at high efficiency points. The closed channel impeller of L pump is matched with the guide vane and has good reliability. It is widely used in water supply and drainage of cities, agriculture, ships, industries, etc. it can meet the needs of low lift and large flow, and the flow can reach 2000m3/h. It is suitable for pumping clean water or slightly polluted water. There are six specifications in total

the installation and maintenance are simple, and the design without pipeline connection is adopted

m pump open impeller, with a chopping device at the inlet, which is composed of chromium alloy and stainless steel, is especially suitable for pressure sewage system, and can be transported through a pipe with a diameter of only 40mm. The axial flow impeller with adjustable blades of P pump has the characteristics of high efficiency and energy saving. It is mainly used in agriculture, urban water supply and drainage and industrial pumping of cooling water, and can be used to control inland waterway systems. It can meet the special needs of low lift and large flow, and is suitable for pumping clean water or slightly polluted water

the structure is compact and simple, and no special installation is required. It only needs to fall on the shoulder of the shell base. The multi blade closed impeller of R pump is cast with cast iron or stainless steel, and water enters from one or both sides (double suction). It is especially suitable for [China Plastics News] Huafeng spandex () people who say it is used in agricultural sprinkler irrigation and various industrial applications, such as supplying clean water, process water, spraying and cooling water. Satisfiable

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