What is the gas binding phenomenon? How to prevent it? What is the cause of it?

　　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 liquid from the storage tank into the pump, and thus the pump cannot transport liquid even when it is started. This phenomenon is known as gas entrapment, indicating that the centrifugal pump does not have self-priming capability; therefore, the tank must be filled with liquid before starting. Solution: Fill the forward shell with liquid before starting. Ensure proper sealing of the housing; the valves and faucets used for watering must not leak, and good sealing is essential.

　1. 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 liquid from the storage tank into the pump, and thus the pump cannot transport liquid even when it is started. This phenomenon is known as gas entrapment, indicating that the centrifugal pump does not have self-priming capability; therefore, the tank must be filled with liquid before starting. 2. How to prevent air locking in centrifugal pumps Fill the casing with liquid before starting. Ensure proper sealing of the housing; the valves and faucets used for watering must not leak, and good sealing is essential.

The phenomenon in which a centrifugal pump cannot bear a load after starting due to gas formation inside the pump, or where the pump shuts down during the process of bearing a load, is known as gas locking of the pump. To avoid this issue, ensure thorough exhausting of air before starting the pump; for pumps used with low-temperature liquids, the pump body must be properly pre-cooled before exhausting air and starting the pump.

I can see that everyone makes good use of Baidu Knows. To put it simply, air locking occurs when a centrifugal pump isn’t filled properly; air remains in the pump chamber and can’t be expelled, preventing liquid from entering the pump and resulting in no flow. The solution is to fill the pump properly and ensure that there is no more air leakage

This situation only occurs in centrifugal pumps. In simple terms, a pump is designed to transport liquids, but when it is started, there is some gas inside the pump. Due to the large difference in density between liquid and gas, it isn’t possible to create a sufficient negative pressure in the area around the impeller to draw in liquid; as a result, the impeller spins idly without performing any work, and the liquid isn’t transported. To avoid vapor lock, the pump must be filled with the liquid to be transported before it is started up; this process is commonly referred to as priming the pump. Under normal and positive pressure conditions, the inlet valve of the pump is opened first, followed by the outlet vent valve, and priming is complete once liquid begins to flow out. However, in cases of negative pressure, the outlet vent valve cannot be opened; otherwise, not only will the pump not be properly primed, but suction will also occur, affecting the operation of the entire tower. The vacuum line at the pump outlet should be opened; if there is no return line to the tank connected to the pump, the inlet valve should be opened and vacuuming should be carried out for a few minutes. If that still doesn’t work, manually start the pump at the midpoint (the same procedure applies when starting a canned motor pump as well).

Air locking phenomenon: When there is gas present in the pump chamber of a centrifugal pump, during startup the gas rotates at high speed inside the impeller, and this prevents the creation of a sufficient vacuum level. As a result, the liquid at the pump inlet cannot be drawn into the pump chamber, causing the pump to run idle. This phenomenon is known as air locking. The avoidance method is to prime the pump before starting it, until liquid is seen flowing out at the pump outlet.

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