Important properties when choosing a valve

The valve is the control component in the fluid transmission system, which has the functions of cut-off, regulation, diversion, prevention of backflow, pressure stabilization, diversion or overflow pressure relief. The valves used in the fluid control system range from the simplest stop valve to various valves used in the extremely complex automatic control system, with a wide variety of varieties and specifications. The valve 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. The valves are also divided into cast iron valves, cast steel valves, stainless steel valves, chromium molybdenum steel valves, chromium molybdenum vanadium steel valves, dual phase steel valves, plastic valves, non-standard valves and other valve materials according to the materials.

A valve is a device used to control the direction, pressure and flow of fluid in a fluid system.

The valve is a device that makes the medium (liquid, gas, powder) in the piping and equipment flow or stop and can control its flow.

Experts from pump valve network said that the valve is a control component in the pipeline fluid transmission system. It is used to change the passage section and the medium flow direction, and has the functions of diversion, cutoff, throttling, check, diversion or overflow pressure relief. The valves used for fluid control range from the simplest cut-off valve to various valves used in extremely complex automatic control systems, with a variety of varieties and specifications. The nominal diameter of the valves ranges from extremely small instrument valves to industrial pipeline valves with a diameter of 10m. The valve can be used to control the flow of various types of fluids such as water, steam, oil, gas, mud, various corrosive media, liquid metal and radioactive fluid. The working pressure of the valve can range from 0.0013mpa to 1000MPa, and the working temperature can range from - 269 ℃ to 1430 ℃. The valve can be controlled by various transmission modes, such as manual, electric, hydraulic, pneumatic, turbine, electromagnetic, electromagnetic, electro-hydraulic, electro-hydraulic, pneumatic, spur gear, bevel gear drive, etc; Under the action of pressure, temperature or other sensing signals, the valve can act according to the predetermined requirements, or simply open or close without relying on the sensing signals. The valve relies on the driving or automatic mechanism to make the hoist move up, down, slide, swing or rotate, so as to change the size of its flow passage area to achieve its control function.

The important properties of the valve are as follows: sealing performance

The sealing performance of the valve refers to the ability of each sealing part of the valve to prevent medium leakage, which is the most important technical performance index of the valve. There are three sealing parts of the valve: the contact between the opening and closing parts and the two sealing surfaces of the valve seat; Matching of packing with valve stem and stuffing box; Connection between valve body and bonnet. The leakage at the former part is called internal leakage, that is, if the valve is not closed tightly, it will affect the ability of the valve to cut off the medium. For block valves, internal leakage is not allowed. The leakage at the last two places is called external leakage, that is, the medium leaks from the inside of the valve to the outside of the valve. External leakage will cause material loss, pollute the environment, and even cause accidents in serious cases. For flammable, explosive, toxic or radioactive media, external