Created on:2021-06-02 10:23

Key points of screw pump

Key points of screw pump

① Application in the field of hydraulic engineering, screw pump is mainly used in the feed hydraulic system of precision machine tools to ensure the smooth movement of related components. Based on the same purpose, hydraulic elevators for carrying passengers mostly choose them as the hydraulic oil source. Because of the screw pump's characteristics of large flow and good self-priming performance, some large-scale hydraulic pump stations use this kind of pump as oil replenishing and preloading pump. Screw pump is often used to supply oil in deck machinery equipped with low pressure and large displacement hydraulic motor.

② Parameter calculation and selection as screw pump is gear pump in essence, the key points and precautions of parameter selection and selection are basically the same as gear pump.

③ Precautions

a. The selection of working medium although the requirements of screw pump for working medium are not as harsh as other hydraulic pumps, due to the different materials of main working parts of different types of screw pump, the working medium should be selected in strict accordance with the product samples or operation instructions of the pump, so as to extend the service life of the pump.

b. Installation

I. The installation position of the pump should be spacious to facilitate maintenance.

II. Place the unit on the foundation with anchor bolts, and tighten the anchor bolts after correction.

III. the diameter of oil suction and pressure pipes of the pump shall not be less than the diameter of the inlet and outlet of the pump, and the oil suction pipeline shall be as short as possible to reduce unnecessary resistance loss; the installation height of the pump shall ensure that the allowable suction vacuum degree is not exceeded during the operation of the pump.

IV. the pipeline shall be equipped with pipe support and pipe clamp, and the pump is not allowed to bear the load of pipeline.

V. before the installation of the pump, the pipeline shall be cleaned thoroughly according to relevant regulations (the welded pipeline must be washed after pickling), and the dirt, oxide scale and welding slag shall be removed to avoid being bitten after entering the pump.

ⅵ the oil suction pipeline shall be equipped with a filter with a filtration accuracy of 40-80 μ m, and the effective flow area shall be 20-30 times of the suction diameter of the pump.

ⅶ. Vacuum gauge and pressure gauge shall be connected at the inlet and outlet of the pump to observe the pressure and working state of the pump.

VIII. When two pumps are in parallel in the same pipeline, a check valve should be installed at the pump outlet to ensure the normal operation of the pump.

"During installation, the pipe joint or flange connecting screw of oil inlet and outlet shall be tightened, and the sealing shall be reliable, so as to avoid air suction or oil leakage, which will affect the performance of the pump.

After the pipeline connection is completed and the prime mover steering is determined, the coupling can be connected. The coaxiality error and end clearance error of the coupling should meet the requirements of the manual.

Xi. After 3-4h operation of the unit, check again. If there is no bad phenomenon, it is considered that the screw pump installation is qualified.

c. Operation, maintenance and storage

I. before start-up, check the tightness of flanges and joints of all pipelines, and make sure they are tight; rotate the coupling to check the flexibility of pump rotation, and make sure there is no stiffness or blockage; for screw pump with oil injection requirements, screw down the oil filling plug of safety valve or remove the cover plate for the first start-up, inject working medium into the pump, and rotate the coupling by hand to ensure the safety The friction pair has enough lubrication; before starting, open all the valves in the oil suction and pressure pipelines to start the pump without load; inching to check the correctness of the pump steering; now the pump can be officially started.

II. During the operation of maintenance, if the pump and prime mover have abnormal noise, stop the pump immediately, check the cause and remove the fault; the outlet pressure of the pump shall not exceed the pressure specified on the nameplate; if the pipeline system fails, stop the pump immediately to check and remove the fault; if the shaft seal of the pump has obvious leakage, stop the pump to remove the fault or replace the seal; the pump shall be cleaned according to the instructions Regular maintenance is carried out. Generally, the minor repair cycle is three months and the major repair cycle is 12 months.

III. If the pump is not used for a long time, it is better to separate it from the prime mover. The warehouse should be kept dry and well ventilated to avoid corrosion of the pump. When it is used again, if corrosion occurs due to improper storage, it should be disassembled and cleaned again, and oil should be applied during assembly to prevent corrosion.

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