The first DF corrosion-resistant multi-stage pump bracket and the motor flange connection, tighten the bolts, and then the mechanical seal stationary ring uniform fixed in the pump cover with a clean gauze wipe stationary ring on the end surface coated with a small amount of oil, set into impeller mounted the good stationary ring pump covers, and then snap ring assembly on the access shaft. Then packed impeller pump cover on the bracket, and then the impeller sleeve onto the motor shaft, tighten the bolts to prevent loosening. DF corrosion-resistant multi-stage pump body, pump cover mounted on the bracket, tighten the bolts evenly, and hand plate moving the impeller shaft, there should be no severity of friction for the best results. DM-type mine production process of multi-stage pump is given only normal flow should consider to leave a margin for ns <100 large flow unexpectedly lift pump flow margin to take 5% on ns <50 small flow a lift pump flow margin 10% 50 ≤ ns ≤ 100 pump flow margin to take 5% of poor quality and operating conditions of the pump flow margin shall be taken as 10% DG high-pressure boiler multi-stage pump pump overheated boiler feed water The stage pump pump overheat common reason is due to bearing damage caused by friction or due to lack of oil lubrication system, oil is not good cause. Multistage pump boiler feed water pump overheating should first check the lubrication system is short of oil or lubricating oil containing impurities, followed by the investigation and the bearing is damaged. Cover the gap is too small for just overhaul pump overheating should also check the Rolling or bracket. After the inspection of the pump is still fever should check the shaft is bent or two-axis misalignment, check the impeller balance, adjusting the pump or adjust the two-axis concentricity, clear the impeller balance hole, multi-stage pump shaft in order to ensure the boiler feed water with the rotation of the impeller balancing, troubleshooting. DY oil seal multistage centrifugal pump in accordance with the structure type can be divided into a set-piece, rotary vane, slide valve, four trochoidal. Seal multistage centrifugal pump to the vacuum pump of the most widely used in the art, it can be used alone as a low vacuum exhaust device with a pump, vacuum pump can also be used as a high-vacuum exhaust foreline demanding multistage centrifugal pump components. Therefore, it has been in many sectors of the national economy, such as vacuum, electronics, light chemicals, iron and steel, non-ferrous smelting and other industrial sectors play an increasingly important role. Oil seal multistage centrifugal pumps are equipped with gas ballast device, it is also pumping wet gas. But now is not suitable for pumping high oxygen, explosive, corrosive to ferrous metals, chemical pump seal oil, containing particles of dust gas.