Design of the check valve

Lift check valve - equipped with a disc sealing element that closes the flow by seating on a valve seat. The axis of movement of the disc and the axis of the passage coincide.

As soon as the force of the flow directed under the disc exceeds the force of the spring holding it in the closed position, the disc rises and opens the passage. When the working medium is supplied from above the disc, the vector of the flow force coincides with the vector of the spring force, and the disc remains in the closed position.

Lift check valves are spring-loaded and in some modifications, they can also be equipped with a lever mechanism.

The body of the lift valve is made of cast iron or steel. They are characterized by a large mass and significant dimensions, but at the same time, they are reliable, not demanding of the quality of the working environment, and hermetically close the reverse flow. Lift check valves are usually installed in heating systems, industrial facilities, and boiler rooms. Spring-loaded check valves are recommended for installation in places with high flow turbulence.

Swing check valve — the sealing element consists of a steel disc, and the flow closure is achieved by seating the disc on the valve seat. When the valve is opened, the disc moves radially relative to the axis of the flow.

Swing check valves are characterized by high reliability, tight closure, and high throughput, but they, like lift check valves, are bulky and have significant dimensions. Since the disc is closed by the force of gravity, the installation of a swing check valve is allowed only on a horizontal pipeline or on a vertical pipeline with a flow direction from bottom to top.

Some designs of swing check valves provide for the possibility of additional installation of a lever closing mechanism.

Swing check valves are installed in industrial facilities, heating networks, large heating points, and boiler rooms.

Ball check valve - its sealing element is a polymer, rubber or cast iron vulcanized layer that covers the passage by its own weight. When the flow is in the forward direction, the ball is displaced into a chamber located outside the passage, and in the absence of flow or in the reverse direction, it covers the passage.

The body of the ball check valve is made of cast iron, and the connection to the pipeline can be either by coupling or flange.

Ball check valves are used in water supply and drainage systems, as well as in pipelines that transport viscous or contaminated liquids. Ball check valves have low hydraulic resistance, but like the previous designs, they are heavy and bulky.

Installation of a ball check valve is only allowed on a horizontal pipeline or on a vertical one with the flow direction from bottom to top.

Disc check valve - the sealing element of such a valve is a steel disc, the axis of which coincides with the axis of the pipeline. The flow is cut off by seating the disc on the stationary seat. In some designs, a polymer sealing ring is installed in the disc or in the seat to improve sealing.

The valve disc is held by a spring, so it remains in the closed position until the force of the forward flow on the disc exceeds the force of the spring. In the open position, the disc is located in the passage, and the flow passes through the clearance between the disc and the valve body.

Compared to previous designs, disc check valves have less weight and smaller dimensions, but they introduce significant hydraulic resistance, and for repair, they need to be removed from the pipeline.

Installation of a disc check valve is allowed in any position. They are used in boiler houses, heating stations, heating and water supply networks.