Gas cylinder pressure reducing valve, also called gas cylinder pressure reducing valve, is a pressure reducing valve that reduces the high-pressure gas in the gas cylinder to the low-pressure gas pressure required for experiments and working conditions.
Working Principle
Using a piston type decompression structure, it is used in petrochemical industry, chemical fiber, lighting appliances, heat treatment, metallurgy, glass, food, medicine, electronics, national defense aerospace, aviation, etc. Leading the field of outlet decompression of nitrogen cylinders, oxygen cylinders, helium cylinders, hydrogen cylinders, argon cylinders, and acetylene cylinders. These gases are generally stored in special high-pressure gas cylinders. When in use, the gas pressure is reduced to the range required by the experiment through the imported cylinder pressure reducing valve, also called the imported gas cylinder pressure reducing valve, and then finely adjusted through other control valves to allow the gas to be input into the system.
Because they are used in high-pressure systems, precision instrument systems, or medical laboratory systems, the occasions are very important. How to regulate and test pressure is very critical. We use the American VTON cylinder pressure reducing valve as the For example, the usage method is introduced in detail
1. Pressure regulating method of imported gas cylinder pressure reducing valve
The high-pressure chamber of the gas cylinder pressure-reducing valve is connected to the cylinder, and the low-pressure chamber is the gas outlet. , and leads to using the system. The indication value of the high pressure gauge is the pressure of the gas stored in the cylinder. The outlet pressure of the low pressure gauge can be controlled by the adjusting screw.
When using, first turn on the main switch of the cylinder, and then turn the low-pressure gauge pressure adjustment screw clockwise to compress the main spring and drive the diaphragm, spring pad and ejector rod to open the valve. In this way, the imported high-pressure gas enters the low-pressure chamber through throttling and decompression from the high-pressure chamber, and leads to the working system through the outlet. Turn the adjusting screw to change the height of the valve opening, thereby adjusting the flow of high-pressure gas and reaching the required pressure value.
Pressure reducing valves are equipped with safety valves. It is a device that protects the pressure reducing valve and makes it safe to use. It is also a signaling device that signals failure of the pressure reducing valve. If the outlet pressure rises on its own and exceeds a certain allowable value due to damage to the valve pad, valve or other reasons, the safety valve will automatically open for exhaust.
2. Instructions for use of imported gas cylinder pressure reducing valves
According to different usage requirements, gas cylinder oxygen pressure reducing valves have many specifications. The high inlet pressure is mostly 15MPa, and the low inlet pressure is not less than 25 times the outlet pressure. There are many outlet pressure specifications, generally 0.25 MPa, and the maximum outlet pressure is 3.5-4 MPa
When installing a gas cylinder pressure reducing valve, you should determine whether its connection specifications are consistent with the joints of the cylinder and the system being used. The pressure reducing valve and the cylinder are connected by a hemispherical surface, and the nuts are tightened to make them fit perfectly. Therefore, the two hemispherical surfaces should be kept smooth during use to ensure a good air-tight effect. High-pressure gas can be used to blow away dust before installation. When necessary, materials such as polytetrafluoroethylene can also be used as gaskets.
Oxygen cylinder pressure reducing valves should be strictly prohibited from contact with grease to avoid fire accidents.
When stopping work, the remaining air in the pressure reducing valve should be released, and then the adjusting screw should be loosened to prevent the elastic element from being compressed and deformed for a long time.
The gas cylinder pressure reducing valve should avoid impact and vibration, and should not be in contact with corrosive substances.
But there are also some gases, such as ammonia and other corrosive gases, which require special pressure reducing valves. Common ones on the market include special pressure reducing valves for nitrogen, air, hydrogen, ammonia, acetylene, propane, water vapor, etc.
1. Open the pressure reducing valve of the imported gas cylinder
After correctly installing the pressure reducer on the gas cylinder valve and opening the gas cylinder valve, turn the adjusting screw 14 clockwise. Compress the adjusting spring 13, the transmission spring pad 1, the transmission diaphragm 2 and the push rod 12, thereby causing the valve 10 to leave the valve seat. The imported high-pressure gas enters the low-pressure chamber 11 from the high-pressure chamber 9 through the throttling gap between the valve and the valve seat, and is diffused and decompressed. The pressure of the high-pressure chamber is indicated by high-pressure gauge 5 and low-pressure gauge 6 respectively.
2. Adjustment and operation of the imported gas cylinder pressure reducing valve
The pressure after decompression is adjusted by turning the adjusting screw left and right, mainly by changing the pressure generated by the adjusting spring 13. This causes the gas pressure balanced with it below the membrane 2 to change to achieve the required working pressure. At this time, the valve on the equipment behind the pressure reducer can be opened for work.
3. Close the pressure reducing valve of the imported gas cylinder
When the work is completed, as long as the adjusting bolt is fully loosened, the valve 10 will close and seal under the action of the high-pressure gas force and the valve spring.
4. Safety valve
Safety valve 3 is a pressure relief device to maintain the safe use of the pressure reducer and a signaling device for pressure reducer failure.
When the output pressure rises to more than 115 to 15 times the maximum output pressure due to damage to the valve seal, valve seat or other reasons, the safety valve will automatically open for exhaust and will automatically close when the pressure drops to the allowable value.
Safety matters that should be paid attention to during use
1. Fix the gas cylinder on the wall, pillar or special cart. Be sure not to overturn the gas cylinder to the ground.
2 Before use, make sure the pressure reducer is in good condition and check for grease contamination. If there is grease, it should be cleaned by professionals. Impurities, dirt and dust on the pressure reducer should be removed.
3 Check whether the cylinder valve is contaminated by grease, whether the thread is damaged, and whether there are impurities and dirt. If grease is found or the threads are damaged, the cylinder should no longer be used and the gas supply unit should be notified of these conditions. Remove impurities, dirt and dust from the cylinder valve.
4 Install the pressure reducer on the gas cylinder and tighten all the connecting joints.
5 Before opening the pressure reducing valve of the imported gas cylinder, turn the pressure reducer adjusting screw counterclockwise until the adjusting spring is no longer compressed.
6 When opening the pressure reducing valve of the imported gas cylinder, do not stand on the front or back of the pressure reducer. The cylinder valve should be opened slowly to high pressure to indicate the cylinder pressure reading.
7 Rotate the pressure reducer adjustment screw clockwise to bring the low-pressure meter to the required working pressure. If it is too high, loosen the adjusting screw, release some air and then readjust.
8 To check whether there is air leakage, first close the cylinder valve, and then turn the adjusting screw one turn counterclockwise. If the reading of the high pressure gauge decreases, then there is a leak in the high pressure part of the pressure reducer or the cylinder valve. If the low pressure gauge reading decreases, then there is a leak in the low pressure part of the pressure reducer or in the pipelines and equipment behind the pressure reducer. If the reading of the high pressure gauge decreases and the reading of the low pressure gauge rises at the same time, it means there is air leakage at the valve seat of the pressure reducer. All of the above leaks can be detected using leak detection solutions with good leak detection results and safety.
10. Close the gas valve when the gas cylinder is not in use. When the work is completed, first close the pressure reducing valve of the inlet gas cylinder, and then open the valve on the welding, cutting tool or equipment to discharge all the gas from the pressure reducer. Then close the valve you just opened, and then adjust the screw counterclockwise until the adjusting spring is no longer compressed.
11 When using the pressure reducer, strictly implement the "Gas Cylinder Safety Supervision Regulations" issued by the State Administration of Labor.
12 If the imported gas cylinder pressure reducing valve and supporting pressure gauge are found to be damaged or abnormal, they should be repaired immediately.
13 The repair of the pressure reducing valve of the imported gas cylinder must be carried out by professionals. You can find a VTON repair center in the United States.
14 The parts to be replaced during repair should be parts of the same model from our factory, otherwise problems may occur or the product's performance requirements may not be met.
15 The pressure reducer has been under pressure for a long time and should be regularly sent to a specialized maintenance department for maintenance, usually once a year.
16. In order to prevent misuse, some special pressure reducing valves use special connections with cylinders. For example, the pressure reducing valve for hydrogen inlet cylinders and the pressure reducing valve for propane inlet cylinders both use left threads, also known as reverse threads, and special attention should be paid during installation.