The centrifugal multi-stage pump is a simple series connection of many single-stage pumps. When combined, its output water pressure can be very large. It is a kind of centrifugal pump, and it also depends on the rotation of the impeller to obtain centrifugal force and thus material. When the gas density reaches the working range of the mechanical vacuum pump, it is pumped out, thereby gradually obtaining a high vacuum. The centrifugal multi-stage water pump relies on the change of the pump cavity volume to achieve suction, compression and exhaust, so it is a centrifugal multi-stage water pump with variable volume.
The main structure of the centrifugal multi-stage pump is composed of water inlet section, water outlet section, middle section, tail cover, impeller, pump body, pump shaft, bearing, sealing ring, stuffing box and other components.
1. The impeller is the core part of the multi-stage pump. It has a high speed and a large output. The blades on the impeller play a major role. The impeller must pass a static balance experiment before assembly. The inner and outer surfaces of the impeller are required to be smooth to reduce the friction loss of the water flow.
2. The inlet section, outlet section and middle section are also called pump casings, which are the main body of the multi-stage pump. Play a supporting and fixing role, and connect with the bracket for mounting the bearing.
3. The function of the pump shaft is to connect the motor with the coupling, and transmit the torque of the motor to the impeller, so it is the main component that transmits mechanical energy.
4. The bearing is a component that is sleeved on the pump shaft to support the pump shaft. There are two types of rolling bearings and sliding bearings. Rolling bearings use tallow as a lubricant. Refueling should be appropriate. Generally 2/3~3/4 of the volume is too much to generate heat, too little and there is noise and heat! Sliding bearings use transparent oil as lubricant, add oil to the oil level line. Too much oil will seep out along the pump shaft and drift low, too few bearings will overheat and burn out and cause accidents! During the operation of the pump, the temperature of the bearings will be as high as 85 degrees and generally run around 60 degrees. If it is too high, find the cause. (Whether there are impurities, whether the oil is black, and whether water has entered) and deal with it in time!
5. The sealing ring is also called the leakage reducing ring. The gap between the impeller inlet and the pump casing is too large to cause the high-pressure water in the pump to flow to the low-pressure area through this gap, which affects the pump's water output and reduces efficiency! Too small a gap will cause friction and wear between the impeller and the pump casing. In order to increase the return resistance, reduce internal leakage, and delay the service life of the impeller and the pump casing, it is advisable to have a sealing ring at the junction of the inner edge of the pump casing and the external aid of the impeller to keep the gap between 0.25 and 1.10 mm.
6. The stuffing box is mainly composed of packing, water seal ring, packing tube, packing gland and water seal pipe. The function of the stuffing box is mainly to close the gap between the pump casing and the pump shaft, so that the water in the pump does not flow to the outside and the outside air does not enter the pump. Always maintain the vacuum in the pump! When the pump shaft and the packing friction generate heat, the water seal pipes the water into the water seal ring to cool the packing! Keep the pump running normally. Therefore, special attention should be paid to the inspection of the stuffing box during the running inspection of the pump! The stuffing should be replaced after 600 hours of operation.
