Check valves
- Slovak term: Slovenský termín
- A check valve is a non return valve used to prevent the reverse flow of a fluid or gas from a downstream section of a pipe to the section of pipe upstream of the valve. It can be referred to as a check valve or a non return valve (American Society of Sanitary Engineering 2007).
- A valve that allows the flow of a liquid in only one direction but closes when the normal direction of flow is reversed (WHO 2006).
Explanation
A check valve is the simplest form of a back flow protection device. It is designed to stop the reverse flow of a fluid or gas in a pipe system. It can be constructed in the form of a single check or a double action check valve, called a double check valve (World Plumbing Council Working Group 2008).
Example
Check valves are used on pump discharge lines for pump protection and on building services to prevent draining of plumbing lines back into the distribution system. A single check valve is not a backflow prevention device (Symons et al. 2000).
A check valve is found in a common stop tap with a vertical inlet and horizontal outlet that incorporates a loose jumper valve. It can be also an inline check valve that incorporates a simple swing check valve or spring loaded check valve. Both are opened by the inlet positive pressure and closed when the pressure on the upstream side of the valve is less than the pressure on the down stream side (World Plumbing Council Working Group 2008).
References
- American Society of Sanitary Engineering (2007) Plumbing Dictionary. Sixth Edition
- WHO (2006) Health aspects of plumbing
