Non-return valve

Non-return valve

A non-return valve ensures that the water that runs through it cannot flow back.

It is ideal, for example, in the following situations:

• On the suction connection of a self-primping pump such as a garden pump or booster pump when you connect the pump to an already drilled well. In this case, the non-return valve operates like a finger on a straw: i.e. the sucked-in water stays in the straw when you cover the hole with your finger.

• On the delivery connection / in the drainpipe of a submersible pump. When the pump is finished pumping, the drained water can no longer run back into the space.

Operation of a non-return valve

Non-return valves come in different models, including ones that are spring-loaded, and are often used in the suction pipes of self-priming water pumps. When water is drawn in, the suction force opens the spring-loaded valve, and closes it automatically as soon as the pump stops pumping.

Non-return valves often are used to drain water: for example, with a submersible pump. The device is fitted with a ball that closes the entire valve by making use of gravity. When water is pushed through a non-return valve, the ball is pushed to the side (the Y shape), allowing the water to pass through freely. As soon as no more water is pushed through, the ball automatically drops down, closing off the device and stopping the water from flowing back.