A checking valve is a type of fittings that protects various equipment, pipelines, pumps, and pressure vessels from changing the direction of the flow of the medium in the system. It also restricts the flow of the medium from the system in case of partial destruction of the system.
The checking valve allows fluid to flow through the pipeline in one direction and prevents it in the opposite direction. It is an essential component of any water supply, heating, sewerage, and industrial process plant. It is also used in leakage prevention systems in washing machines and dishwashers. These devices have a variety of designs, each of which has its advantages and areas of application. Their common feature is that the valve opens when a certain pressure is reached and closes when the pressure drops below the set value.
The disc check valve
It is distinguished by its low price, low metal consumption, and unpretentious installation. During the opening, the valve is displaced along the flow axis while remaining in the flow area, which results in a low flow rate. Check valves of this type are used for water, compressed air, and non-aggressive liquids. They are most widely used in heating and water supply systems due to their simplicity in installation and low prices. The check valve body is made of brass or stainless steel, the plug is made of brass or polymer, the seal is NBR or EPDM, the spring is made of stainless steel.
Lift check valve
They are characterized by high reliability and maintainability, they are undemanding to installation and the quality of the working environment. They provide a high closing tightness. Lift check valves are used at industrial facilities and boiler houses, on pipelines transporting compressed air and steam.
When the flow is directed under the valve, the valve is displaced, opening the flow area, and in the opposite direction of flow, the pressure difference across the valve becomes an additional force holding the valve in the closed position. The valve body and screw cap are made of cast iron, steel, or bronze, the valve is made of steel or brass, the spring is made of stainless steel.
Ball check valve
It has a high flow capacity, simple shape of the flow path, and high closing tightness. Checking valves of this type are not demanding on the quality of the working medium and can be used on pipelines transporting cold water, and liquids. The closing element is a rubberized cast iron ball held in a closed position by gravity. A ball check valve is installed on vertical pipelines with the flow direction from bottom to top or on a horizontal pipeline with a ball chamber upward.
The valve body and cover are made of cast iron, the valve is made of a rubberized cast iron ball.
There are numerous types of checking valves and finding them is not a hard thing to do. But, you are at risk of getting inferior products if you do not look for a reputable check valve manufacturer.