Causes of pump cavitation
Causes of pump cavitation
Causes of pump cavitation 1. Air leakage in the inlet pipe. 2. The liquid level is too low and air is inhaled. 3. The inlet pipeline design is unreasonable, and the highest point is higher than the impeller (only refers to the suction of water). 4. The installation method is unreasonable. In some places, the atmospheric pressure is low, and the cavitation margin of the selected pump itself is large, or the pipe diameter is too small, and the resistance is large. The suction can only be used when the water is reversed. 5. The pressure of liquid vaporization increases. 6. The selection is wrong, and the pump is seriously deviated from the best working point. 7. Eliminate the damage of the air valve, the air is not exhausted or other reasons cause the pipeline and pump body to not exhaust the air. The specific reason: the cavitation of the water pump is caused by the vaporization of water. The so-called vaporization is the process of water transforming from liquid to vapor. The vaporization of water has a certain relationship with temperature and pressure. Under a certain pressure, when the temperature rises to a certain value, the water starts to vaporize; if the pressure drops to a certain value at a certain temperature, the water will also vaporize. This pressure is called the vaporization pressure of water at that temperature. If during the flow process, the pressure in a certain area is equal to or lower than the vaporization pressure corresponding to the water temperature, the water vaporizes there. After vaporization occurs, many small bubbles of steam and gas are formed. When the vapor bubbles flow from the low pressure area to the high pressure area with the water flow, the vapor bubbles burst under the action of high pressure, and the high pressure water flows to the space occupied by these original vapor bubbles at a very high speed, forming an impact force. The metal surface is fatigued and severely damaged under the action of water hammer pressure. Therefore, we call the entire process of the formation, development and rupture of the bubble, which results in the destruction of the material, as cavitation. The cause of cavitation of the water pump is at the inlet of the water pump. Due to the vacuum formed by the high water absorption and the high-speed placement of the impeller, the pressure there is often very low, which provides conditions for the vaporization of water. When the pressure drops to the vaporization pressure of the water temperature, a large number of water vapor bubbles formed due to vaporization will flow into the high pressure area inside the impeller along with the unvaporized water. The vapor bubbles will burst under high pressure in a very short time and condense again. Water, the water around the bubble quickly concentrates to the center of the broken bubble and produces a great impact. This impact force acts on the wall of the water pump, forming cavitation on the water pump.
