The basic structure of the self-priming pump is composed of six parts: the impeller, the pump body, the pump shaft, the bearing, the sealing ring and the stuffing box. They act as different roles.
1. The impeller is the center of the centrifugal pump. It has a relatively high rotational speed and a large output. The blade on the impeller plays the primary role. The impeller is subjected to static balance test before the device. The surface of the impeller is lubricated to reduce the conflict of water flow.
2. The pump body is also called the pump casing, which is the main body of the self-priming centrifugal pump. It supports the fixing effect and is connected to the bracket of the device bearing.
3. The effect of the pump shaft is that the coupling is connected to the motor and the torque of the motor is transmitted to the impeller, so it is the primary component for transmitting mechanical energy.
4. The bearing is a member that supports the pump shaft on the pump shaft, and has two kinds of rolling bearings and sliding bearings. Rolling bearings use butter as a lubricant to refuel properly. Usually 2/3~3/4 of the volume will heat too much, too little and there will be noise and heat! The sliding bearing uses the bright oil as the lubricant, refueling to the oil level line.
5. the seal ring is also known as the leak reduction ring. The empty space between the impeller inlet and the pump casing is too large to form the water in the high pressure zone of the pump flowing to the low pressure zone through the empty space, affecting the water output of the pump, and the power is reduced! If the empty space is too small, the impeller and the pump casing will collide and wear. In order to reduce the leakage resistance by adding the backflow resistance, the service life of the impeller and the pump casing is postponed. The sealing ring is installed at the inner edge of the pump casing and the external contact of the impeller, and the sealed open space is preferably between 0.25 and 1.10 mm.
6. The stuffing box is mainly composed of packing, water sealing ring, packing tube, packing gland and water sealing tube. The effect of the stuffing box is primarily to close the open space between the pump casing and the pump shaft, so that the water flow in the pump does not flow to the outside and the outside air does not enter the pump.
Self-priming pump selection principle:
1. Note that the type and performance of the selected pump meet the requirements of process parameters such as flow, head, pressure, temperature, cavitation flow, and suction.
2. must meet the requirements of the media characteristics.
For pumps that transport flammable, explosive, toxic or valuable media, shaft seals are required to be reliable or leak-free pumps, such as magnetic drive pumps, diaphragm pumps, and shield pumps; for pumps that transport corrosive media, corrosion resistance is required for convection components. Materials, such as AFB stainless steel corrosion-resistant pumps, CQF engineering plastic magnetic drive pumps; for the transport of pumps containing solid particulate media, the convection components are required to use wear-resistant materials, if necessary, the shaft seals are washed with a clean liquid.
3. High mechanical reliability, low noise and low vibration.
4. The overall cost of equipment, operating, maintenance and management fees should be considered economically.
5. The centrifugal pump has the characteristics of high speed, small volume, light weight, high efficiency, large flow, simple structure, no pulsation of infusion, stable performance, easy operation and convenient maintenance.