Structure characteristics and function of pressure reducing valve

Structural features and functions of pressure-reducing valve:

Pressure reducing valve is a valve in the body of the opening of the opening and closing of regulating the flow of medium, the medium pressure is reduced, at the same time with the aid of the role of the valve after pressure adjust the opening of open-close part, keep the valve after pressure within a certain range, and the valve body or valve after the injection of cooling water, reduce the temperature of medium, the valve is called desuperheating valve to relieve stress. The characteristics of the valve, is in the case of constant changes in the inlet pressure, keep the outlet pressure and temperature in a certain range.

　　The pressure-reducing valve can be divided into thin film type, spring film type, piston type, lever type and bellows type; According to the number of seats can be artificial single seat and double seat; According to the position of the disc can be divided into positive action and reaction.

　　(1) pressure regulation range: it refers to the adjustable range of the pressure reducing valve output pressure P2, which requires the specified accuracy. The pressure regulating range is mainly related to the stiffness of the pressure regulating spring.

　　(2) pressure characteristic: it refers to the characteristic of output pressure fluctuation caused by input pressure fluctuation when flow g is a constant value. The smaller the output pressure fluctuation, the better the characteristics of the reducing valve. The output pressure must be lower than the input pressure -- a constant value that essentially does not change with the input pressure.

　　(3) flow characteristics: it refers to the persistence of input pressure -- timing, and output pressure changing with the change of output flow g. When the flow g changes, the smaller the change in the output pressure, the better. Generally, the lower the output pressure is, the less it fluctuates with the output flow.

Selection of pressure reducing valve

According to the requirements of the use of the valve to select the type and pressure adjustment precision, and then according to the required Z large output flow choose its size. When determining the air source pressure of the valve, make it larger than Z high output pressure 0.1mpa. The pressure reducing valve is generally installed after the water filter, before the oil mist or fixed value device, and pay attention not to connect its inlet and outlet in reverse; Valve should be used to relax the knob, so as not to affect the performance of the diaphragm often compression deformation.

　　The 200X pressure-reducing valve is an intelligent valve that USES the energy of the medium itself to regulate and control the pipeline pressure. Used for domestic water supply, fire water supply and other industrial water supply systems. The outlet pressure of the main valve can be adjusted through the pressure relief pilot valve of the regulating valve. The outlet pressure will not change with the change of the inlet pressure and the inlet flow. The outlet pressure can be maintained on the set plant safely and reliably, and the set value can be adjusted according to the need to achieve the purpose of reducing pressure. The valve is accurate in decompression, stable in performance, safe and reliable, easy to install and adjust, and long in service life.

1. Reduce pressure and stabilize pressure. Generally, the air pressure output of the air compressor fluctuates from 0.2 to 0.3Ma, and the pressure during shutdown is from 0.7 to 0.8MPa, and the pressure during restart is from 0.4 to 0.5MPa. The function of the filter pressure relief valve is to stabilize the output pressure, the pressure after decompression should be in 0.4--0.5MPa. The knob on the pressure relief valve is used to adjust the output pressure.

Two, filtering, filtering valve can filter out most of the water and impurities in the compressed air. Routine maintenance of the ZYX74X valve requires regular inspection of the pressure gauge on the valve to see if the pressure fluctuates with the pressure of the air compressor. If the air pressure fluctuates with the air compressor, the reducing valve has failed. You can try adjusting the adjusting knob of the reducing valve. If this does not work, you should consider replacing the filtering reducing valve of the heart. Because the unstable air pressure can affect the service life of high-speed mobile phones. In addition, also regularly to filter the pressure relief valve discharge water. More advanced filter reducing valve can automatically drain, when the pressure is small to a certain value, the drainage valve will automatically open. Some of the older filter relief valves are regularly opened below the drain valve to prevent water. Water is usually drained every 15 to 30 days.　

Working principle of pressure reducing valve, use method of pressure reducing valve

Oxygen, nitrogen, hydrogen, argon and other gases are often used in physical and chemical experiments. These gases are normally stored in dedicated high pressure gas cylinders. When in use, the gas pressure is reduced to the range required by the experiment through the pressure reducing valve, and then the gas is input into the system through other control valves. The commonly used reducing valve is oxygen reducing valve, referred to as oxygen meter.

1. Operating principle of oxygen pressure reducing valve

The high pressure chamber of the oxygen relief valve is connected to the cylinder, and the low pressure chamber is the gas outlet and leads to the service system. The high pressure gauge indicates the pressure of the gas stored in the cylinder. The outlet pressure of the low pressure meter can be controlled by adjusting screw.

When in use, first open the cylinder master switch, and then clockwise turn the low-pressure gauge pressure adjusting screw, make it compress the main spring and drive the film, the spring pad and the jack to open the valve. In this way, the imported high-pressure gas enters the low-pressure chamber after being throttled and decompression from the high-pressure chamber, and passes through the outlet to the working system. Turn the adjusting screw to change the opening height of the valve, so as to adjust the flow of high-pressure gas and reach the required pressure value.　

Relief valves are fitted with safety valves. It is a device to protect the pressure reducing valve and make it safe to use. It is also a signal device for the failure of the pressure reducing valve. If the outlet pressure rises by itself and exceeds a certain allowable value due to damage to the valve pad, valve or other reasons, the relief valve will automatically open the exhaust.

2. Use method of oxygen pressure reducing valve

(1) according to the different requirements of use, oxygen reducing valve has many specifications. The high inlet pressure of Z is mostly, and the low inlet pressure of Z is not less than 2.5 times of the outlet pressure. Export pressure specifications are more, generally, Z high export pressure is.

(2) when installing the pressure-reducing valve, determine whether its connection specifications are consistent with those of the cylinder and the connector of the operating system. The pressure reducing valve and cylinder are connected by a hemispherical connection, and the two are completely matched by screw-nut. Therefore, the two hemispheres should be kept clean when using to ensure a good airtight effect. Dust can be blown off with high pressure gas before installation. If necessary, ptfe can also be used as washers.

(3) oxygen pressure reducing valve should be strictly prohibited to contact grease, so as to avoid fire accident.

(4) when stop working, the remaining air in the reducing valve should be removed, and then loosen the adjusting screw to avoid deformation of the elastic element under pressure for a long time.

(5) the pressure reducing valve should avoid collision and vibration, not contact with corrosive substances.

3. Other gas pressure reducing valve

Some gases, such as nitrogen, air, argon, etc., can use oxygen pressure reducing valves. But there are some gases, such as ammonia and other corrosive gases, you need a special reducing valve. Common on the market have nitrogen, air, hydrogen, ammonia, acetylene, propane, water vapor and other special reducing valve.

The use of these valves and precautions are basically the same as the oxygen valve. However, it should also be pointed out that the special pressure reducing valve is generally not used for other gases. In order to prevent misuse, some special relief valves and cylinders with a special connection. For example, both hydrogen and propane use left thread, also known as reverse thread, special attention should be paid to the installation.

The installation and maintenance of the pressure reducing valve should pay attention to the following matters:

For easy operation and maintenance, the valve is generally installed upright in a horizontal pipe. During installation, it should be noted that the flow direction of the pipeline medium should be the same as the arrow shown on the valve rest. To prevent pressure overpressure behind the valve, a relief valve shall be installed not less than 4M from the valve outlet.