In general, poppet valves, which are responsible for connecting and disconnecting and regulating the fluid flow rate, have wide and important applications in various industries, including the utility industry. Mechanical check valves used in engine houses are usually gate valves, metal floor and one-way valves, which are of brass (gear connection) or cast iron (with flange connection) in different sizes.
Other types of valve categories can be defined according to the working pressure, working temperature or even the desired operating fluid in the industry and facilities. , polymer check valves and steel check valves etc.
In addition, industrial check valves are divided into types of thread check valves, welded check valves, flange check valves, and plastic check check valves according to the size and type of connection. They are divided. In terms of function, valves can be divided into types of mechanical valves with manual adjustment or automatic adjustment, and in terms of operation system, they can be divided into types of electric and mechanical valves. p>
Plug or clock valves
Samavari valves are for low flows and are made in three ways, Piswar valves are a type of Samavari valves. This type of valves consists of a rod with a hole in the middle of the valve for The flow of water is created and placed in a chamber that is machined and polished on the inner surface of the valve.
This type of valve, like the gate valve, has very little resistance to the flow. They produce water. To open and close the samouri valve, it is enough to turn the valve handle 90 degrees. Usually, samouri valves are used as a two-mode control device (off/on). Because (1) they are relatively cheap, (2) they remain in the same position when adjusted, and (3) employees can clearly see the open or closed state of the valve.
Globe valves
The name of the spherical valve is derived from the external shape of its body, which is spherical, and the internal structure of the valve is such that the liquid changes direction by 180 degrees from the point of entering the valve to the point of exiting the valve. br>The construction of the valve and the seat of the spherical valve is such that as soon as the flow is established, their contact is cut off. Also, not fully opening the ball valve does not cause the ball valve to wear out. Therefore, the ball valve can be used to regulate and control the flow. Proportionality of the number of turns of the valve handle with the volume of the liquid outlet makes it easy to adjust the flow rate by hand. The direction of the fluid flow changes unlike the slide valve.
- The change in the direction of the fluid flow causes turbulence in the ball valve.
- The turbulence in the ball valve increases the pressure drop.
- In the ball valve The pressure drop is higher than the sliding valve.
Angle Valve
This type of ball valve is the same as the ball valve, with the difference that there is a 90 degree angle between the inlet and outlet of the ball valve. This type of valve creates less pressure drop than the spherical valve, and due to the special shape of the valve, it saves the consumption of piping connections and also the time required for installation.
Ball valve
These types of valves are also called impact valves. The flow of water in this type of valve passes through the hole of a spherical ball which is located in a completely polished spherical position. To open and close this type of valve, just like Samavari valve, only 90 degree rotation of the valve handle is enough. These valves also create little resistance to water flow. This type of valves can be used in hot and cold water piping as well as low pressure gas piping.
Gate Valve
Sliding valves are mostly used in places where they want to completely close or open the fluid flow. One of the properties of these valves is the low pressure drop along the length of the valve, for this reason, these valves are used in long pipes. When the drawer or gate is completely directed up and out of the way of the fluid flow, and as a result, there is no resistance to the passage of the flow, but if the drawer is directed to its lowest position, as a result, the fluid changes direction and collides with The drawer causes turbulence and pressure drop. In plumbing, most of the pipe and valve are connected together (by welding or by screw), but in general, the connection between the valve and the pipe is done by flange and bolt, and to prevent leakage between the flange and pipe, a gasket is placed.
Sliding valve is a blocking valve that is suitable for two open or closed states. This valve has a seat on which the tongue of the valve sits and blocks the passage of fluid.
Back Water Valve
This type of valve is only used in sewage piping and works exactly like a free one-way valve. In situations where, for various reasons, sewage returns to the building's sewage inlets, these valves prevent this action. This type of valve is usually installed in places such as the basement of the building, which has a low height compared to the sewage disposal site, to prevent the return of sewage.
Non-return or Check Valves
It is transferred from one-way valves to prevent the return of liquid or gas sent to the destination. The reasons for its use in industries and household appliances are as follows:
In homes: water is placed on the entrance to the building, in case of a water cut, the amount of water in the household appliances and inside the pipe stored water does not return to the main pipe.
They place on the inlet pipe of the water heaters so that the water stored in the water heater does not empty due to the water cut or the pipe breaking inside the building. because the furnace may continue to work and cause the water heater to burn.
In refineries, a one-way valve is placed on the output pipe of the pump. can't return because as a result of the return, in addition to wasting the energy used to send it, the receiving party may also face an immediate shortage of materials, more importantly, the pressure of the return liquid that went through the same path may be reversed, and as a result, the pump escapes rotate the center with increasing speed and the speed becomes so high that the heated pump fails and even explodes.