The check valve is an element of pipe fittings used in various situations. In such a device, the movement of the locking element is parallel to the axis of the main fluid flow inside.
Shut-off and control valves with an electric actuator are focused on changing the flow rate of the working medium that moves through the pipeline.
The shut-off valve can be made of bronze, steel and cast iron, it is used to adjust the liquid or gas flow through the pipeline, and also as an element that blocks this flow. Based on the classification of the design features of the device, as well as its purpose, there is also an
electromagnetic shut
- off
valve, which allows you to control the environment in the system at a distance, as well as flange and coupling types of valves.
There are many varieties of this type of reinforcement. The choice of a specific one depends on the features of the process, as well as on the tasks that are assigned to the safety shut-off valve. An important factor is the types of systems where it is used.
Valves are widespread enough, acting as shutoff valves, which allows for high-quality sealing in the shutoff body, while the design of the device is quite simple. Valves are used for gaseous and liquid media having a wide range of operating properties: pressure and temperature. They are usually used on pipelines having a small diameter, since with large sizes one has to face a situation where the force required to control the valve increases significantly, and the design is complicated to ensure a correct fit of the shutter placed on the seat of the housing.
The shut-off valve has a number of advantages:
- the possibility of use in conditions of high pressure and temperature, vacuum, aggressive and corrosive environments;
- ease of repair and maintenance directly in operation.
According to the design features, the valves are largely similar to the valves, however, the principal difference is the way the shutter is moved, which gives the valves additional advantages:
- for full opening requires a small shutter speed, so the mass and height of the device is also quite small;
- the tightness of the shutter in the valves is much easier to provide than in the valves;
- when the valve is opened and closed, friction of the valve seal is almost eliminated, which significantly reduces the degree of wear;
- the use of a bellows is permitted as a seal for the fittings.
The safety shut-off valve also has certain disadvantages:
- high hydraulic resistance, which with a significant diameter of the passage and a high velocity of the medium creates significant energy losses, which makes it necessary to increase the initial pressure in the system;
- the diameter limits the application of the valve;
- in most designs there are stagnant zones where the accumulation of mechanical impurities from the working medium takes place, and this significantly increases corrosion in the valve body.
In any case, this type of reinforcement is widely used.