What Do You Know About Valves? Five Common Types of Valves
The valve, is an important adjustment device in the fluid transportation system, which can basically control the on-off, flow and flow direction of the fluid. There are many types and specifications of valves, and the valves used for different work requirements are also different. The working principles, advantages and disadvantages of five common types of valves are described is this article.
Published: Jun 16, 2022
The valve is a control component in the fluid conveying system, which has the functions of cut-off, regulation, diversion, prevention of backflow, voltage stabilization, diversion or overflow and pressure relief. Valves used in fluid control systems, from the simplest shut-off valve to various valves used in extremely complex automatic control systems, have a wide variety and specifications. Valves can be used to control the flow of various types of fluids such as air, water, steam, various corrosive media, mud, oil, liquid metal and radioactive media. Check out the working five common types of valves now.
Ball Valve
Ball valve is a common main valve type, which is improved from a plug valve and replaces the plunger with a sphere. The ball is provided with a through hole, and the rotation of the ball can control the cooperation between the through hole and the flow channel to adjust the opening and closing of the valve. The valve seat can be made of suitable material according to the working conditions. It is widely used because of its good sealing performance, simple structure and easy operation and maintenance.
Advantages:
• High tightness
• Low resistance of straight-through flow path
• Various caliber sizes and wide range of fit
• Can be used for porous applications such as 3-way ball valves
Disadvantages:
• Metal spheres are expensive to manufacture
• When the fluid contains impurities or large particles, the ball and seat are easily damaged
Globe Valve
It is called because its shape resembles a ball. It opens or closes the flow channel with the cooperation of the valve plate and the valve seat. It is often used for cutting off and throttling. The flow channel in the valve body is S-shaped, when the fluid passes through, the flow direction will be changed, which will increase the resistance and reduce the fluid pressure.
Advantages:
• Small working stroke and short opening and closing time
• Excellent fluid shut-off and flow control capabilities
• Low friction on the sealing surface and high durability
Disadvantages:
• Fluid pressure is reduced by resistance
• High force required for valve operation
• Not suitable for sediments and viscous fluids
Gate Valve
The valve rod is used to drive the gate to make a linear motion, and the gate is lifted to open or close the flow channel. When the gate is half-opened, the fluid impacting the gate will easily cause the valve seat to vibrate and be damaged, so it is not suitable for throttling use. It is only suitable for fully open or fully closed occasions.
Advantages:
• Short distance between the ends
• Low resistance of straight-through flow path
• The fluid is perpendicular to the gate, requiring less force to open and close
Disadvantages:
• Applicable only when fully open or fully closed
• The gate travel is high, and the space above is required for operation
• Takes longer to turn on and off
Check Valve
Also known as one-way valve, as the name implies, it only allows fluid to flow in one direction. Under the action of fluid pressure in one direction, the valve flap opens to make the flow passage unobstructed; on the contrary, when the fluid pressure in the other direction acts, the valve flap is closed. The effect of preventing backflow.
Advantages:
• Simple structure, easy to operate and maintain
• Prevent fluid backflow and maintain unidirectional flow
Disadvantages:
• Pay attention to fluid direction during installation
• If the pressure is too low, the cut-off capability may be affected
• Instantaneous opening and closing may damage the disc impact
Butterfly Valve
The opening and closing and flow can be adjusted by controlling the rotation angle of the valve plate. Butterfly valve can be divided into elastic seal and metal direct seal. The elastic seal uses the rubber ring to prevent leakage and has good low pressure sealing performance, but the rubber ring has limitations on temperature and pressure; the metal direct seal is the direct contact of the metal surface, and the working temperature range is relatively high and wide.
Advantages:
• Simple construction and easy installation
• Smaller in volume and weight than other valves of the same size
• Large flow diameter and low resistance
Disadvantages:
• Large flow diameter, not suitable for small flow control
• Gaskets are susceptible to operating temperature and pressure
Published by Jun 16, 2022
Source :Stone Enterprise