Yancheng Qingquan Pump Industry Co., Ltd.
Contact: Jin Qiang
Address: No. 2, Building 10, Area B, No. 96 Huanghai East Road (Dayang Industrial Park), Tinghu District, Yancheng City
The operation of the axial flow pump includes filling, starting, running and stopping. Compared with the centrifugal pump, the axial flow pump is different in structure. The axial flow pump has its special place. Today I will introduce the running trajectory of the axial flow pump for everyone:
Medium and small axial flow pumps, especially horizontal axial flow pumps or small vertical flow axial pumps , are mostly installed above the water surface, so before starting, the pump casing and suction bell mouth must be filled with water. Similarly, in the presence of air, vacuum cannot be formed inside the pump and suction pipe. In this case, generally one or more electric vacuum pumps are set up, and the air in the pump casing and the horn is drawn out by using them to form a vacuum, so as to achieve the purpose of filling water. Large vertical axial flow pumps are generally installed below the water surface, so the pump casing, impeller, and suction bell mouth are immersed in liquid, and there is no need to fill it with water before starting. Therefore, no air extraction device It can start quickly, which is also one of the characteristics of the axial flow pump, which is a favorable condition for achieving automatic program startup.
The starting sequence and method of the axial flow pump are basically the same as those of the centrifugal pump. However, it should be pointed out that for the activation of various types of centrifugal pumps, its outlet valve is closed, and the outlet valve of the axial flow pump should be opened and started. This is because when the flow of the axial flow pump is equal to zero, , Its power is greater than two times or more than the rated power; at the same time, it will also exacerbate the generation of cavitation. This is because the deviation angle of the inlet angle of the liquid flow from the blade is increased. This phenomenon can only disappear when the maximum efficiency point is above 60%.
Axial flow pump cavitation occurs when the pressure at the impeller inlet or the local pressure in the pump body drops below the vaporization pressure of water. Therefore, in order to prevent cavitation when the pump is running, the installation height must meet the requirements in the sample, but cavitation cannot be completely avoided. Today, I will introduce the axial flow pump cavitation in detail for everyone. s reason:
For axial flow pumps, the value at which the pressure at the inlet of the impeller is lower than the atmospheric pressure on the water surface of the inlet pool is usually called the suction vacuum. When the axial flow pump is running, if the water level of the inlet pool drops too much, the degree of vacuum suction will increase. When the vacuum degree exceeds the allowable vacuum degree, cavitation will occur; If the suction flow channel is not ideal, the velocity and pressure distribution of the water flow entering the impeller will be uneven, thereby generating a local low pressure area.