Check valve

Check valve – this is one of the types of valves, the main purpose of which is to prevent movement of the working fluid in the opposite direction. Reverse movement – a dangerous process, and it is for the protection of equipment, pipelines, vessels and check valves are installed.

The principle of operation of such a check valve. If there is no pressure in the conduit or the fluid, the valve is initially in the closed position. When the working fluid begins to flow through the pipeline, its pressure on the diaphragm valve is increased, and the valve opens. It stays open until such time as the pipeline is supported by the operating pressure, that is the minimum pressure that is necessary to keep the valve open.If the operating pressure is absent, the valve is locked, if the conduit has a constant pressure, then for closing the valve needs only one side of the valve to reduce the pressure abruptly.

The check valve may be of different design. A little bit about the most common types of valves.

Often, the check valve has a check valve structure, and consists of two compartments, as a jumper between them closed by a spool. That is, under the influence of spring spool or cargo valve seat is pressed, and the motion of the medium in the right direction, it lifted without disturbing the move. When movement stops working environment or changes its direction, the spool by spring or weight falls in valve seat, thereby blocking the movement of the working environment.

Another structural view of the check valve is a swing-check valve. Its design resembles a butterfly valve, even though the drive is attached only to the top edge of valve seat. When the working fluid is moving in the right direction, the disc is pressed against the top of the valve body, and when the movement stops, it falls under its own weight in the valve seat.

Sometimes plumbing for small diameter pipes mounted ball check valves. Here, the locking element is made in the form of a ball that spring presses the seats. This type of shut-off valves can be easily used in vertical pipes.

Also noteworthy is flanged dvustvorochnye valves and valve springs reversed. The peculiarity of their design and method as valves have a small width of the developer, and is widely used in terms of narrow spaces. Check valves type merger are divided into: coupling, flange, flanged. Flanges and flanged check valves mainly used in industry, such as metallurgy, chemical, water, pumps, thermal and nuclear power.

By material valves, they are divided into: iron, brass, stainless steel valves. By design are divided into: lifting and turning.

In the lifting plate of the return valve , passing pressurized working fluid rises above the valve seat and the reverse movement of the medium is lowered and pressed against the valve seat. For a good seal between the valve cover and tail set spring plates which increases the adhesion to the saddle. Non-return valves of this design are used in vertical and oblique lines. With the use of a damping device is smooth passage plates with avoiding water hammer.

In fact, the check valves are of many varieties, and each are used exclusively in the industry, because choosing valves for their needs need to have some knowledge.