Valves are used in various industries. Drum liquid level three impulse control, boiler combustion control, etc. are controlled by the valve opening and closing degree. The purpose of our algorithm is also to control the valve opening and closing degree to achieve automatic control . The valve has a wide range of uses, so it plays a big role. For example: valves can control the operation of boilers and steam turbines in power plants; in petroleum and chemical production, valves also control the normal operation of all production equipment and process flows. Nevertheless, valves are often overlooked when compared to other products. For example: When installing machinery and equipment, people often focus on the main machinery and equipment, such as compressors, high-pressure vessels, boilers, etc. These practices will reduce the overall production efficiency or stop production, or cause various other accidents, so we It is necessary to know and understand the valve.
Classification of valves
There are many types of valve products, and the terms are completely unified. Some are divided by purpose (such as chemical industry, petroleum, power station, etc.), some are divided by medium (such as water vapor, air valve, etc.), and some are divided by material (such as cast iron valve , Cast steel valve, forged steel valve, etc.), some according to the connection type (such as internal thread, flange valve, etc.), some according to temperature (such as low temperature valve, high temperature valve, etc.). At present, most of our habits in China are distinguished by the type of pressure and structure. That is, according to the nominal pressure: ≤1.6MPa is a low pressure valve, pressure 2.5, 4.0, 6.4MPa is a medium pressure valve, ≥10MPa is a high pressure valve, and more than 100MPa is an ultra high pressure valve.
The main types by structure are:
Plug valve, gate valve, globe valve, ball valve-used to open or close the medium flow in the pipeline.
Check valve (including foot valve)-used to automatically prevent the medium in the pipeline from flowing backward.
Throttle valve—used to regulate the flow of pipeline medium. Butterfly valve—used to open or close the medium in the pipeline. It can also be used for adjustment.
Safety valve—Used on boilers, containers, equipment and pipelines. When the medium pressure exceeds the specified value, it can automatically remove the excess medium pressure to ensure production and operation safety.
Reducing valve—Used to automatically reduce the pressure of the medium in the pipeline and equipment. When the medium is passed through the gap of the valve disc, resistance is generated to cause pressure loss, and the purpose of decompression is achieved.
Drainer—Used to automatically drain condensate from steam pipes to prevent steam loss or leakage.
分类 Classified by use and function
Stop valve type-mainly used to shut off or connect the medium flow. Including gate valve, globe valve, diaphragm valve, ball valve, plug valve, disc valve, plunger valve, ball plug valve, needle instrument valve and so on.
Regulating valve type-mainly used to adjust the flow and pressure of the medium. Including regulating valve, throttle valve, pressure reducing valve and so on.
Check valve type-used to prevent the medium from flowing backward. Including various structures of check valves.
Diverter valve type-for separating, distributing or mixing media Including distribution valves and traps of various structures.
Safety Valves——Used for safety protection when the medium is overpressured. Includes various types of safety valves.
分类 Classified by pressure
Vacuum valve-a valve whose working pressure is lower than the standard atmospheric pressure.
Low pressure valve-a valve with a nominal pressure PN less than 1.6MPa.
Medium pressure valve-a valve with a nominal pressure of PN 2.5 ~ 6.4MPa.
High pressure valve-a valve with a nominal pressure of PN10.0 ~ 80.0MPa.
Ultra high pressure valve-a valve with a nominal pressure PN greater than 100MPa.
分类 Classified by medium temperature
High temperature valve-a valve with t greater than 450'C.
Medium temperature valve-120 'C less than t less than 450' C valve.
Normal temperature valve--40 'C less than t Valve less than 120' C.
Cryogenic valve--100 'C less than t less than -40' C valve.
Ultra-low temperature valve-valve with t less than -100 'C.
Classified by valve body material
Non-metallic valve—such as ceramic valve, glass steel valve, plastic valve.
Metal valve--such as copper alloy valve, aluminum alloy valve, lead alloy valve, titanium alloy valve, Monel valve,
Cast iron valve, carbon steel valve, cast steel valve, low alloy steel valve, high alloy steel valve.
Metal body lined valves-such as lead lined valves, plastic lined valves, enamel lined valves.
This classification method is divided according to principle, function and structure. It is currently the most commonly used classification method at home and abroad. General gate valve, globe valve, throttle valve, instrument valve, plunger valve, diaphragm valve, plug valve, ball valve, butterfly valve, check valve, pressure reducing valve
Safety valves, traps, regulating valves, foot valves, filters, blowdown valves, etc.