In most systems, the movement of the liquid through tubing or pipes occurs through the change in pressure in the system. Water and other liquids flow from high pressure to low pressure following natural laws.
However, in some types of applications, pressure changes can occur in the system, which would cause the water in the tube or the pipe to flow backward. This change in pressure and flow direction could pull contaminated water through the system, creating serious health issues and potential costly cleaning, repair, and replacements of components.
To prevent these issues, a water check valve is placed in the pipe or tube. This is a simple valve that is pushed open on the inlet side with the pressure from the system. Should the pressure on the inlet side of the valve drop below a set level, the valve closes on the inlet side, preventing the water from flowing back up the system.
Design Options
There are many different designs in a water check valve. A ball valve is a simple, effective and low-cost option, with the ball moving in the interior of the valve to seal if any change in pressure below the system parameters is detected.
In addition to the ball style of water check valve, they can also prevent backflow through the use of membrane or diaphragm. Swing or disc valves are also available, but these can close extremely quickly, resulting in a rapid change in pressure. This rapid change can cause a water hammer or a vibration through the pipe or tube caused by the pressure surge.
For effective use of the check valve, it is important to match the size and pressure range of the valve to the requirements of the system. These valves can be very precise and respond to even slight pressure differences to immediately seal the inlet port and prevent any backflow through the valve into the system.
