A small issue with the pump

Too high an inlet medium temperature or a long idle time can cause the liquid to vaporize; furthermore, improper design of the inlet and outlet pipe diameters can also lead to gas entrapment. An inlet elbow that is too close to the pump body can also cause this issue

Before starting a centrifugal pump, it is essential to fill the pump casing with water before initiating operation; otherwise, the pump will be unable to draw in liquid, which will cause the pump to overheat and vibrate, fail to produce water flow, and experience \"air locking\" – a condition that can damage the pump and lead to equipment failures. 　　When there is air inside the centrifugal pump casing, the lower density of air compared to that of the liquid results in a smaller centrifugal force. As a result, the pressure difference between the surface of the liquid in the tank and the pump’s suction inlet is not sufficient to force the liquid in the tank into the pump; in other words, the centrifugal pump does not have self-priming capability, which prevents it from pumping liquid. This phenomenon is known as the \"suction lock\" phenomenon. To fill the pump with liquid, a bottom valve equipped with a filter is usually installed at the bottom of the suction pipe. This bottom valve serves as a check valve, and the filter prevents solid substances from entering the pump and damaging the impeller or interfering with its proper operation.

I’ve learned a lot, haha. Centrifugal pumps: www.hnppump.com

Here, the pump inlet is under negative pressure, and this phenomenon occurs when the shaft packing seal is not functioning properly

When a centrifugal pump is started, if there is air inside the pump, the low density of air results in a weak centrifugal force generated upon rotation; as a result, the low pressure created in the center area of the impeller is not sufficient to draw in liquid. Consequently, even though the centrifugal pump starts up, it is unable to perform its pumping function. This phenomenon is known as air locking. This means that the centrifugal pump does not have self-priming capability; therefore, the pump must be filled with the liquid to be transported before it is started. Of course, if the suction inlet of a centrifugal pump is placed below the liquid level of the fluid to be transported, the liquid will flow into the pump automatically; this is a special case. The suction line of the centrifugal pump is equipped with a foot valve to prevent the liquid filled in before startup from flowing out of the pump. A filter screen prevents solids in the liquid from being drawn in and causing blockages. The control valve installed in the discharge line of the pump is used for starting and stopping the pump as well as regulating flow rate. Air entrapment occurs when there is air inside the pump, usually during startup. It is caused by insufficient removal of air from the pump, which results in the pump being filled with air; this problem can be resolved by filling a buffer tank at the inlet

1. Water is present in the medium, or the vaporization temperature of the medium decreases at low pressures, resulting in the generation of gas and causing gas entrapment. 2. There are too many light components in the seal oil. 3. The seal oil contains water. 4. There are too many light components in the medium.