The shut-off valve is a valve, the purpose of which is to quickly shut off the pipeline as a whole or part thereof according to technological requirements or in the event of an emergency. Its main advantage is speed, since when the device is closed, the spring works instantly. Spring charging is carried out by means of an electric or pneumatic actuator.
Shut-off valve: varieties
This type of valve may have a piston or membrane pneumatic actuator. In addition, the shut-off valve can belong to one of the types: checkpoints, angles, one- or two-seat. By the closing method, this type of reinforcement happens: spring, pneumatic, electromagnetic or closing load.
Scope of application
A shut-off valve with a straight-through body is used to transport pulp-like abrasive or contaminated media. In such a device there are no stagnant zones. A double-acting steel angle shut-off valve with a piston hydraulic actuator is used when working in a high-pressure environment.
At the moment, this type of reinforcement has such design features that steam is most actively used as a control medium in it. Such a valve works in 1.5-10 seconds. Its cylinder and body are sealed with gaskets wound spirally from corrosion-resistant steel with an asbestos layer. When compared with the external environment, the tightness of this type of valve is quite high, which contributes to the lack of gaskets in them. All this allows you to significantly increase their reliability during operation and increase efficiency.
Shut-off valve for water: the difference between the new version and the old
The design of this type of reinforcement has been substantially changed, therefore, several significant differences can be traced. The most important features in the new modification are:
- increased resistance to polluted environments;
- increased level of tightness;
- reliability is maximized;
- response speed surpasses old modifications;
- the pipeline may overlap in two directions: forward and reverse.
This type of valve is most often used in the energy, pulp and paper and food industries, as well as in water treatment and its preparation.
Requirements for shut-off valves
The main requirement in this case is the response speed. Compliance with this is ensured by equipping the valve with a spring or several. Typically, plate or coil springs are used in such structures. When using an electric actuator, the valve design assumes the presence of latches that hold the spring in a cocked state, and they are controlled by electromagnets. The automatic shut-off valve responds instantly and, if necessary, switches to standby mode as quickly.
All varieties of this type of fittings can be made from different materials: steel, plastic, cast iron or stainless steel.