Comparison and applications of submersible pumps and external tank pumps
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Hello everyone, we are a LPG filling station with 25 years of experience. Our factory has 4 underground storage tanks. Four submersible pumps are used to pump the liquid LPG from the tank to the loading platform. What I want to ask is, what if we don’t use a submersible pump to extract the liquid, but instead use an external pump? Could the decrease in pressure inside the tank cause the liquefied gas to vaporize when liquid is discharged, and if so, could the gaseous petroleum gas be drawn into the pump? Will it damage the structure of the pump?
Are you referring to the underground storage tanks at LPG (liquefied petroleum gas) filling stations? If so, there are generally two types: submersible pumps and external tank pumps. Submersible pumps use a positive-pressure inlet, while external tank pumps use a negative-pressure inlet. When external tank pumps are used, there is usually a return pipe that leads back to the storage tank; when the pump starts, gas is sent back to the tank through this return pipe. Once the liquid level rises, a flow control valve on the return tank is closed, thereby allowing the liquid to be delivered downstream. After the pump has been in use for some time, the liquid level drops; as long as liquid can still flow into the pump, cavitation will not occur. Cavitation occurs if the liquid level difference exceeds the pump’s suction vacuum level ； As for what the original poster asked about, I don’t understand what is meant by gases entering the pump body