Analysis on the use characteristics of the hottest

With the improvement of scientific and technological level in recent years, submersible electric pumps and single foundation vertical axial flow pumps have been widely used in the design of pump stations. This paper makes a preliminary discussion on the use characteristics of submersible electric pumps and single foundation vertical axial flow pumps:

1 relative advantages

submersible electric pumps are mature substitutes for conventional pumps imported from abroad, The single foundation vertical axial flow pump, called DP pump and electromechanical one machine pump, has been widely used abroad and at home. It is the latest water pump developed by some water pump plants in China in recent years. The single foundation vertical axial flow pump makes up for the shortcomings of submersible pumps, Absorb the advantages of submersible pumps. At the same time, simplify the installation and maintenance of axial-flow pumps. Compared with conventional pumps, submersible electric pumps and single foundation vertical axial-flow pumps have the following advantages:

1.1 civil engineering investment savings

pump stations using submersible electric pumps and single foundation vertical axial-flow pumps can save 30% - 40% investment in civil engineering investment in southern China, and the benefit is very significant (most submersible pump stations in southern China do not have water parts); However, considering the problem of antifreeze in winter in Heilongjiang Province, it is also necessary to set up the above water part of the plant, resulting in no significant benefit. But compared with the conventional pump station, it can cancel the motor floor and reduce the height of the plant. It can also save some investment

1.2 it is extremely convenient to install

take the majaitun pump station in the main stream dike of the Songhua River in Zhaodong city as an example, four 700 mm diameter submersible electric pumps were installed in place in half an hour, The installation and commissioning of three 700 mm diameter conventional axial-flow pumps in Xinxing pump station of Songhua River embankment in Zhaodong city took half a month. The installation accuracy of the conventional water pump is required to be high, and the concentricity tolerance should be less than 0.03 ~ 0.04mm/m. In addition, the installation team in our province is mostly installed by the civil construction team, and the installation capacity is limited. The accuracy of the light-weight installation of the vehicle is insufficient, so that the pump shaft swings too much after the pump is started, which increases the output of the water pump or overloads the motor, and it cannot be started in serious cases. The pump shafts of several water pumps at Zhaoyuan County lidushan station are all eccentric, with a measurement of 50mm, and one water pump has been unable to start. Considering the problem of antifreeze in winter, some pump stations have water pump bell mouth and impeller frost heave damage. Therefore, the water pump needs to be lifted out in winter. At the same time, the influence of uneven settlement of the foundation caused by the operation of the pump motor on the concentricity should also be considered. Considering the annual minor repair and normal overhaul, the quantities of installation and maintenance in the second year are very large, and bring great hidden dangers to the safe operation of the pump station. Through the above comparison, the advantages of submersible pump are too prominent

1.3 convenient operation, reliable operation, less auxiliary equipment and low maintenance cost

conventional axial flow pumps need to inject lubricating water before starting, and cooling wood needs to be injected into the transmission device during operation. Therefore, water supply pipelines and valves need to be added, which makes the start and operation of the pump complex and difficult to realize automatic control, Submersible electric pumps and single foundation vertical axial flow pumps abandon the above disadvantages

2 relative characteristics

although submersible electric pumps and single foundation vertical axial flow pumps have many common advantages, they also reflect their different characteristics in the process of use

2.1 it is difficult to deal with the fault of submersible electric pump

submersible electric pump was introduced from British weir company in the early 1980s. As a national key scientific and technological project, it mainly solves the problems of motor sealing and leakage, and the submersible electric pump can be independently grouped and disassembled. The single foundation vertical axial flow pump is an integral part of the pump, which cannot be separated. Submersible electric pumps are equipped with various automatic protection functions such as overheating, motor cavity, oil cavity leakage protection, etc., but once a major accident occurs, the submersible electric pump can only be returned to the factory for maintenance, and the operation and management of the pump station is inconvenient. The failure and annual overhaul and minor repair of the single foundation vertical axial-flow pump are completely aimed at the relevant technical parameters. The maintenance capacity of the pump station can be used without returning to the manufacturer for maintenance, which saves a lot of freight. The repaired pump can be put into use at any time without waiting to be transported back from the manufacturer like a submersible pump

2.2 hydraulic performance

the latent capacity release is slow. The hydropower pump operates in water with good cooling effect, high transmission efficiency of pump and motor, slightly higher efficiency of pump station device than other types of pumps, which can save electric energy. Compared with the single foundation vertical axial flow pump, the transmission shaft is longer, and the power consumption is slightly larger than that of submersible electric pump

2.3 requirements for motor

the motor of submersible electric pump is required to have anti leakage and other protective measures to prevent water from entering the motor. The single foundation vertical axial flow pump adopts ordinary motor, which does not need special protection measures in motor protection

2.4 price

the price of submersible electric pumps with chemical pump power below 200 kW is about 15 ~ 1.8 times that of conventional pumps, and the price of more than 200 kW is similar to that of conventional pumps

the single foundation vertical axial flow pump can not completely replace the submersible electric pump, and the submersible electric pump must also be used in some special occasions. Moreover, the annual audit of the enterprises that have been announced and standardized should be strengthened. The basic vertical axial flow pump also has the disadvantages of too long pump shaft, so that the plant is too high