Is it necessary to install a check valve at the outlet of the submersible pump?

From a regulatory perspective, it still needs to be installed.

This post was last edited by Gorō’s Eight Trigrams Staff on 2015-8-3 at 13:04. The so-called check valve is a one-way valve; when the submersible pump stops operating, the vacuum in the vacuum pipeline is higher than that inside the pump chamber, and air enters the pump chamber through the exhaust port, pushing water into the vacuum pipeline. The function of the check valve is to prevent water from entering the pipeline. The manufacturers of submersible pumps explain that installing a check valve on such pumps serves primarily as a protective measure. 　　1. Protection system: When a submersible pump fails, at the moment the pump stops operating, a vacuum condition exists at the pump’s inlet and at the point where it connects to the system. The pump’s outlet is usually in contact with the atmosphere, and the pressure there will force water into the system, breaking the vacuum. To protect the system, check valves are typically installed at the pump’s inlet and at the connection point to the system. 　　2. Protecting the submersible pump itself Gas backflow can impact the impeller, causing the submersible pump to rotate in the opposite direction. To protect the pump body and other equipment, a check valve is generally installed at the outlet of the submersible pump. Nowadays, more and more units have this check valve installed at the outlet, which helps to protect the pump and the entire system. 　　If the system has strict requirements, two check valves can also be installed; these check valves serve to prevent backflow. Since the container being pumped is in a vacuum state after the submersible pump is turned off, while the pump chamber of the device has the same pressure as the surrounding environment, due to this pressure difference, air from the device is forced back into the container being pumped when the submersible pump is turned off. 　By closing this check valve before turning off the submersible pump, air in the pump chamber will not flow back into the container being pumped. Submersible pumps equipped with a check valve not only improve operational efficiency but also significantly reduce the occurrence of failures.

I think it’s necessary to install it; otherwise, the submersible pump will flow in reverse, and the main shaft might rotate in the opposite direction.

It’s a temporary submersible pump that has been used many times; all you need to do is issue a bill, connect it to electricity, drop it into the water, and turn on the power for it to start pumping water – it doesn’t have any valves.