In physical chemistry experiments, often use oxygen, nitrogen, hydrogen, argon and other gases. These gases are generally stored in a dedicated high-pressure gas cylinder. When using the pressure reducing valve to gas pressure drop to the required range of experiments, and then through the other control valve fine-tuning, the gas input system. The most commonly used pressure reducing valve for oxygen regulator, referred to as oxygen meter. Oxygen pressure reducing valve works Oxygen pressure reducing valve high pressure chamber and cylinder connection, low pressure chamber for the gas outlet, and leading to the use of the system. Indication of high pressure gauge is the pressure of gas stored in the cylinder. Low pressure gauge outlet pressure can be controlled by adjusting screw. Open the cylinder main switch when using, then turn the low pressure gauge pressure adjusting screw clockwise to compress the main spring and drive the diaphragm, spring pad and ejector to open the valve. Such imports of high-pressure gas from the high-pressure chamber after throttling decompression into the low-pressure chamber, and through the exit leading to the working system. Turn the adjustment screw to change the height of the valve opening to regulate the passage of high-pressure gas and achieve the desired pressure value. Relief valves are equipped with safety valve. It is to protect the pressure relief valve and make it safe to use the device, but also the valve failure signal device. If due to the valve pad, valve damage or for other reasons, resulting in the pressure on the outlet and rise above a certain allowable value, the safety valve will automatically open the exhaust. Oxygen valve use (1) according to the different requirements, oxygen valve has many specifications. Most of the highest import pressure, the minimum import pressure of not less than 2.5 times the outlet pressure. Export pressure specifications more generally, the maximum outlet pressure. (2) When installing the pressure reducing valve, make sure its connection specifications are consistent with the cylinder and the system using the connector. Pressure reducing valve and cylinder with hemispherical connection, by tightening the nut so that the two completely match. Therefore, the use of the two hemispherical surfaces should be kept clean to ensure a good airtight effect. Use high-pressure gas to blow off the dust before installation. If necessary, PTFE and other materials can also be used for gaskets. (3) Oxygen valve should be strictly prohibited contact with grease, so as to avoid fire accidents. (4) stop working, the relief valve should be more than air net, and then loosen the adjustment screw to prevent long-term compression of the elastic deformation. (5) relief valve should be avoided vibration, not with corrosive substances in contact. Other gas pressure relief valve Some gases, such as nitrogen, air, argon and other permanent gases, you can use oxygen valve. But there are some gases, such as ammonia and other corrosive gases, you need a special pressure relief valve. Common on the market are nitrogen, air, hydrogen, ammonia, acetylene, propane, steam and other special pressure relief valve. The use of these valves and precautions and oxygen valve is basically the same. However, it should also be noted that special pressure relief valves are generally not used for other gases. In order to prevent misuse, some special pressure reducing valve with a special connection between the cylinder. For example, hydrogen and propane are used left-tooth thread, also known as reverse thread, installation should pay special attention.