Shut-off valves for pipelines: what they are (in simple words), types, application

Leaving home, people shut off the valves that supply water and gas to the apartment. In the fall, utility companies direct the liquid to the heating system of the neighborhood. Plants run raw materials through the pipeline. In all of this, shut-off valves are always used. It differs in purpose and comes in different designs and sizes. 

What are shut-off valves?

To control the flow of liquid in the pipeline, various valves and gate valves are used - these are shut-off valves. When a handle or valve is turned from the outside, the internal parts of the device move, opening or closing the lumen of the pipe. This gives or stops the flow of the medium.

There is constant pressure in the pipes and some fluids and substances have elevated temperatures and corrosive properties. Therefore, the parts that control the medium flow through the system are made of durable metal, they have a reliable fixation.

Types of shut-off valves

The design and purpose of the valves differ depending on what processes in the pipes need to be controlled with its help. It comes with combined properties: not only opens and closes the lumen of the pipe, but also changes the flow rate and other parameters. Some types of valves for pipes by function:

• Stop valves open and close the flow of liquid in the pipes with valves. These are gate valves and valves, as an example - wedge gate valve.
• Pipeline regulating valves change the head, flow rates, and pressure in the system. These include valves, valves, and level indicators.
• Control pipeline valves determine the parameters of medium flow through the pipes. These are test and release valves, sensors.
• Protective pipeline fittings prevent liquid from moving in reverse direction. It prevents sudden pressure jump and protects parts and equipment from breakage.
• Distributive-mixing valves for pipes mix contents coming from different sources. Check and shutoff valves and pneumatic gate valves are used.

In the interior of the shut-off valves, two sealing surfaces are installed on the body and the gate. They seal the joint.

Shut-off valves are used in all industries where pipes are involved. Some of its types by purpose:

• Industrial shutoff valves feature a range of large sizes.

• Sanitary isolation valves are most often ball valves. They are installed on sanitary equipment: toilets, sinks, bathtubs, cisterns, washing machines and dishwashers in front of flexible lines.
• Ship stop valves are installed on vessel equipment and communications.
• Vacuum - applied in systems with pressure lower than atmospheric pressure.

Shutoff valves differ in the pressure they can withstand: high - 100 bar, medium - from 25 to 100 bar and low - 25 bar. This factor must be taken into account in order to avoid emergency situations.

Application of shut-off valves

In the pipeline, shut-off valves regulate the movement of such substances:

• fresh or sea water, steam;
• crude oil, fuel oil, kerosene, gasoline
• machine oil;
• Alkalis, acids, ammonia and other aggressive substances;
• natural gas, etc.

Shut-off valves differ in material, design and sizes depending on what industry and working environments they are designed for. For example, in shipbuilding communications lightweight and compact parts are installed, and in chemical production the resistance to the action of aggressive substances is important.