Pressure reducing valve, safety valve,
pressure regulating valve, pressure relief valve are all pressure valves, mainly the difference in function.
The reducing valve is a valve that reduces the inlet pressure to a required outlet pressure by adjusting it, and relies on the energy of the medium itself to keep the outlet pressure stable automatically. The characteristic of the valve is to keep the outlet pressure and temperature within a certain range when the inlet pressure is constantly changing. Often used in domestic water supply, fire water supply and other industrial water supply system, through the
Regulating Valve decompression pilot valve, you can adjust the outlet pressure of the main valve.
Safety valve used to prevent boiler, pressure vessel and other equipment or pipeline damage due to overpressure valve. When the pressure is slightly higher than the normal working pressure, the safety valve automatically opens to reduce the pressure. When the pressure is slightly below the normal working pressure, the safety valve automatically closes, stopping the discharge of fluid and maintaining the seal. Commonly used in boilers, pressure vessels and pipelines, control the pressure does not exceed the specified value, for personal safety and equipment operation plays an important role in protection.
Pressure relief valve is a kind of hydraulic control valve. The main valve is divided into upper and lower parts by the diaphragm. The lower chamber of the diaphragm is the water channel, and the upper chamber is the control chamber, which controls the opening and closing of the main valve disc. Pilot valve itself is a pressure relief valve, it also has a control room and water channel, valve disc open and close by the control room. The needle valve is the throttle valve, which controls the flow of water in the connecting pipe. Commonly used in the case of too much pressure, when the pressure is greater than the set value, the valve inner piece is opened in time to release the pressure, the pressure is reduced to the original position, and the safety valve is not different, pressure relief valve refers to the liquid, the safety valve refers to the gas, steam.
Pressure Regulator Valve is a device that keeps the medium in an area within a certain pressure range. When the pipe is fed water from the inlet end, the water flows through the needle valve into the main valve control room, and the outlet pressure acts on the pilot valve through the conduit. When the outlet pressure is higher than the set value of the pilot valve, the pilot valve closes and the control room stops drainage. At this time, the pressure in the control room of the main valve rises and closes the main valve, and the outlet pressure no longer rises. When the outlet pressure drops to the pilot valve set pressure, the pilot valve opens, and the control room drains downstream. Because the displacement of the pilot valve is greater than the inlet water of the needle valve, the pressure in the control room of the main valve drops, and the inlet pressure makes the main valve open. In the stable state, the water intake and drainage of the control room are the same, the opening is unchanged, and the outlet pressure is unchanged.
The difference between pressure
regulating valve and pressure reducing valve:
Reducing valve: no matter how the inlet pressure changes, the outlet pressure is reduced to the rated value, play a decompression role.
Pressure regulator: Maintains a constant upstream pressure regardless of downstream pressure and demand changes.
Working principle of pressure reducing valve
1. Direct action film pressure reducing valve
The outlet side pressure increases, the film moves upward, the valve opening decreases, the flow rate increases, the pressure drop should be larger, the pressure after the valve decreases, the outlet side pressure decreases. When the film moves down, the valve opening increases, the flow rate decreases, the pressure drop decreases and the pressure after the valve increases. The outlet pressure behind the valve is always maintained at the constant pressure set by the setting adjusting screw. Suitable for piping of water and non corrosive liquid medium.
2. Direct action bellows type reducing valve
The outlet side pressure increases, the bellows move up, the valve opening decreases, the flow rate increases, the pressure drop is larger, the valve pressure decreases, the outlet side pressure drops. Bellows downward movement, valve opening increases, flow rate decreases, pressure drop decreases, valve pressure increases. The outlet pressure behind the valve is always maintained at the constant pressure set by the setting adjusting screw. Widely used in factories, hotels and other water, steam, air, oxygen, liquefied gas pipeline.
3. Pilot piston type reducing valve
Screw the adjusting screw, top open pilot valve flap, medium from the inlet side into the piston above, because the piston area is greater than the main valve flap area, push the piston to move down, make the main valve open, after the valve pressure balance adjust the pressure of the spring to change the pilot valve opening, so as to change the pressure above the piston, control the opening of the main valve flap, so that the pressure after the valve remains constant. Applicable to all kinds of pressure, all kinds of calibers, all kinds of temperature of steam, air and water medium.
4 pilot film type pressure reducing valve
Same principle as above. Suitable for steam main line or process engineering pressure reduction occasions, can meet the downstream pressure remains unchanged, and reducing valve inlet pressure fluctuation or steam flow dramatic change conditions. Suitable for low pressure, medium pressure, small diameter steam or water and other media.
5. Combined pressure reducing valve
Combined pressure reducing valves are designed to relieve water supply systems in complex operating conditions. They consist of outlet pressure locking system, feedback system, and main valve body. The valve is mainly composed of main valve, control pilot valve, filter, needle valve,
Ball Valve and bypass pipe throttling parts. It is suitable for water, non-corrosive liquid (gasoline, kerosene) and gas whose temperature is less than 80℃ and which need to be reduced to a certain range of equipment and piping system. By adjusting the inlet pressure, it can reduce to a certain outlet pressure value.
6. Lever type pressure reducing valve
Lever pressure reducing valve is used to control the opening of the valve body of the opening and closing parts to adjust the flow of the medium, the pressure of the medium to reduce, at the same time with the valve after the role of the pressure to adjust the opening and closing parts, so that the valve after the pressure to keep in a certain range, in the case of the inlet pressure is constantly changing, keep the outlet pressure in the set range, protect the living production equipment. Applicable to water, steam, air medium pipeline, by regulating the inlet pressure to reduce to a required outlet pressure, when the inlet pressure and flow changes, the energy of the medium itself automatically keep the outlet pressure in a certain range, but the difference between the inlet pressure and the outlet pressure must be ≥0.2MPA/CM.
7. Pilot bellows reducing valve
Structure principle with pilot piston type pressure reducing valve. Suitable for low pressure, medium and small caliber steam medium.
summarize
Safety valve and pressure reducing valve are two types of valves, are special valves. Among them, the safety valve belongs to the safety release device, is a special valve, only when the working pressure exceeds the allowed range of action, to protect the system. Pressure reducing valve belongs to the process valve, can make high pressure logistics decompression, in order to meet the pressure requirements of the system, its working process is continuous.
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