Introduction to commonly used valves

There are many types and complex varieties of valves, mainly including gate valves, globe valves, throttle valves, butterfly valves, plug valves, ball valves, electric valves, diaphragm valves, check valves, safety valves, pressure reducing valves, Yanqi drain valves, and emergency shut-off valves. Among them, commonly used are gate valves, globe valves, throttle valves, plug valves, butterfly valves, ball valves, check valves, and diaphragm valves.

one

Gate valve refers to a valve whose opening and closing body (valve plate) is driven by a lever and moves up and down along the sealing surface of the valve seat, which can connect or cut off the passage of fluid. Gate valves have better sealing performance than globe valves, lower fluid resistance, easier opening and closing, and have certain regulating performance, making them one of the most commonly used shut-off valves. The disadvantage is that the size is large and the structure is more complex than that of the shut-off valve. The sealing surface is easy to wear and repair, and is generally not suitable for throttling purposes. According to the thread position on the valve stem of the gate valve, it is divided into two types: open stem and non rising stem. According to the structural characteristics of the gate, it can be divided into two types: wedge type and parallel type.

2. Shut-off valve

A globe valve is a downward closed valve, and the opening and closing parts (valve discs) are driven by the valve stem to move up and down along the axis of the valve seat (sealing surface). Compared with gate valves, it has good regulating performance, poor sealing performance, simple structure, convenient manufacturing and maintenance, high fluid resistance, and reasonable price. It is a commonly used block valve, generally used for medium and small diameter pipelines.

3 balls

The opening and closing part of a ball valve is a ball with a circular through hole, which rotates with the valve stem to achieve opening and closing. The ball valve has a simple structure, fast opening and closing, convenient operation, small volume, light weight, fewer components, low fluid resistance, good sealing, and convenient maintenance

4. Throttle valve

The structure of a throttle valve is basically the same as that of a globe valve, except for the valve disc. The valve disc is a throttling component, and different shapes have different characteristics. The diameter of the valve seat should not be too large, as the opening height is small and the medium flow rate increases, thereby accelerating the erosion of the valve disc. The throttle valve has a small overall size, light weight, and good adjustment performance, but the adjustment accuracy is not high

5. Plug valve

A plug valve is a valve that uses a plug body with a through hole as the opening and closing component, and the plug body rotates with the valve stem to achieve opening and closing. The rotary cold valve has a simple structure, fast opening and closing, convenient operation, low fluid resistance, fewer components, and light weight. Plug valves are available in straight, three way, and four way versions. Straight-through plug valves are used to cut off media, while three-way and four-way plug valves are used to change the direction of media or divert media.

6. Butterfly valve

A butterfly valve is a butterfly plate that rotates 90 degrees around a fixed axis inside the valve body to complete its opening and closing function. Butterfly valves are small in size, light in weight, and have a simple structure. They are only composed of a few parts and only need to be rotated 90 ": they can be quickly opened and closed, and the operation is simple. When the butterfly valve is in the fully open position, the thickness of the butterfly plate is the only resistance when the medium flows through the valve body, so the pressure drop generated through the valve is very small, so it has good flow control characteristics. Butterfly valves are divided into two sealing types: elastic soft sealing and metal hard sealing. Elastic sealing valve, the sealing ring can be embedded on the valve body or attached to the periphery of the butterfly plate, with good sealing performance. It can be used for throttling, medium vacuum pipelines, and corrosive media. Valves with metal seals generally have a longer lifespan than valves with elastic seals, but it is difficult to achieve complete sealing. They are usually used in situations where flow and pressure drop changes are large and throttling performance is required.