Oxygen valves in physical and chemical experiments, often to use oxygen, nitrogen, hydrogen, oxygen valves in physical chemistry experiments, 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 valve works Oxygen 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. Turn on the main switch when using, and turn the low pressure gauge pressure adjusting screw clockwise to compress the main spring and drive the diaphragm, spring pad and ejector lever 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. Oxygen 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 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) Oxygen valve should avoid shock and vibration, not with corrosive substances. Other oxygen valves, gas 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. Analysis of the causes of oxygen valve combustion and explosion 1. Pipe rust, dust, welding slag and pipe wall or valve friction to produce high temperature combustion This situation is related to the type of impurities, particle size and airflow speed, easy to burn iron with oxygen, And the finer the particle size, the lower the ignition point; the faster the gas velocity, the more prone to combustion. 2. Pipe or valve presence of oil, rubber and other low ignition point of material, ignited in the local high temperature. 3. adiabatic compression of high temperature combustible material combustion. The valve is 15MPa, the temperature is 20 ℃, the valve is atmospheric pressure 0.1MPa, if the valve block speed open, the oxygen temperature after the valve calculated by adiabatic compression up to 553 ℃, which has reached or exceeded the ignition point of some substances. 4. High-pressure oxygen in the combustible ignition point is reduced oxygen pipeline valve combustion incentives. Oxygen pipes and valves are dangerously dangerous in high-pressure pure oxygen, and tests have shown that the detonation of the fire can be inversely proportional to the square of the pressure, posing a significant threat to oxygen pipes and valves.