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Plug valve - Concept, operating principle, structure and function.

Concept: Plug valve is a type of valve widely used in industry, a plug valve is a valve with a valve gate like a cork and punched in the middle so that the flow can pass. There are two common types: using a handwheel and using a lever handle

Plug valve | Maintech
Plug valve | Maintech

Working principle: The position of the valve gate is adjusted by handwheel or lever, When turning the handwheel at an angle of 90°, the valve will be in a closed or fully open state, which helps the button valve close faster than the gate valve.


Structure and operating status of the plug valve | Maintech
Structure and operating status of the plug valve | Maintech

When the handwheel is in a position parallel to the pipeline, the valve is fully open, then the flow passes through the valve gate through the gap on the valve body. When the valve is in the regulating position, the flow will create a vortex and there will be a pressure drop or loss of energy, which also makes the valve easy to wear unevenly due to the force of the flow. When the valve is in the closed position, the gate and the valve body create a high degree of tightness, in the process of changing the position of the valve gate, the valve gate and the valve body will be worn due to the high friction between the valve and the valve body. When worn to a certain extent the valve will not be able to keep the tightness requiring a new valve. To limit this, the stopper valve is designed with a lubricating oil hole, a special oil that helps lubricate the valve gate to reduce friction between the valve gate and the valve body, this oil film also plays a role in increasing the valve's tightness.

Valve type using lubricating oil | Maintech
Valve type using lubricating oil | Maintech

Another way that does not need oil for the valve is to design a valve that is able to move up and down the valve gate with the sealing level, thereby reducing friction when changing the valve position. When the valve gate is lowered, they will create a kin connection between the valve gate and the valve body.

Valve type that does not use lubrication | Maintech
Valve type that does not use lubrication | Maintech

Take a look at the video demonstration below to understand more:

Structure: Plug valve has a very simple structure: - The valve gate (valve button) is punched with a gap in the middle. - Flanges for connecting valve to duct - Valve base to support and act as a shaft for the valve gate - The valve lever is connected to the valve arm, there are 2 types of valve arms: steering wheel and lever


Function:

Stop valves are not used much to regulate fluid flows because when in the regulating position it wears unevenly. Button valves are often used to regulate gas such as gas

 

Compiled by: Maintech Reference source: Vinamain industrial valve textbook



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