The Safe Use of Oxygen Pipes
Attention should be paid to the following aspects to use the oxygen pipeline safely:
(1) The oxygen pipeline should be checked and maintained frequently. Carbon steel pipes should be derusted and painted once every 3 to 5 years to prevent corrosion. The carbon steel main pipe should be purged once every 5 years to prevent the accumulation of rust from causing a fire. The thickness of the pipe wall should be measured once every 5 years, mainly to measure the pipes behind the elbow and regulating valve and ensure the safe thickness of these easily scoured and worn parts. Check the safety grounding device once a year.
(2) The safety devices such as safety valves and pressure gauges on the oxygen pipeline should be inspected once a year, and they should be sensitive and accurate to prevent overpressure and leakages of oxygen.
(3) Oxygen pipelines should not be connected and used indiscriminately, and it is strictly prohibited to use oxygen to blow air or make a fire. Do not make a fire for striking the arc on the operating oxygen pipeline to avoid a fire.
(4) Before the fire operation of the oxygen pipeline, a fire plan should be formulated, which includes the person in charge, operation flow chart, operation plan, safety measures, division of labor, guardian and laboratory tester. The plan needs to be approved by the manager of the safety department and go through the procedures for permitting the fire operation. Oxygen should be clean (dissipated or replaced with nitrogen or oil-free air), and when the oxygen content is less than 23, the fire operation can be conducted. Explosions and casualties caused by insufficient attention to the fire operation, imperfect plans, improper measures (especially isolation from the oxygen source blocking blind plate), untimely or inadequate laboratory supervision occur often, and special attention should be paid.
(5) When major operations on the oxygen pipeline are performed, detailed operation plans including procedures, methods, steps, time, locations, division of labor, scopes, responsibilities, monitoring and confirmation must be formulated in advance, and only after approval and implementation by the relevant managers can they be implemented.
(1) The oxygen pipeline should be checked and maintained frequently. Carbon steel pipes should be derusted and painted once every 3 to 5 years to prevent corrosion. The carbon steel main pipe should be purged once every 5 years to prevent the accumulation of rust from causing a fire. The thickness of the pipe wall should be measured once every 5 years, mainly to measure the pipes behind the elbow and regulating valve and ensure the safe thickness of these easily scoured and worn parts. Check the safety grounding device once a year.
(2) The safety devices such as safety valves and pressure gauges on the oxygen pipeline should be inspected once a year, and they should be sensitive and accurate to prevent overpressure and leakages of oxygen.
(3) Oxygen pipelines should not be connected and used indiscriminately, and it is strictly prohibited to use oxygen to blow air or make a fire. Do not make a fire for striking the arc on the operating oxygen pipeline to avoid a fire.
(4) Before the fire operation of the oxygen pipeline, a fire plan should be formulated, which includes the person in charge, operation flow chart, operation plan, safety measures, division of labor, guardian and laboratory tester. The plan needs to be approved by the manager of the safety department and go through the procedures for permitting the fire operation. Oxygen should be clean (dissipated or replaced with nitrogen or oil-free air), and when the oxygen content is less than 23, the fire operation can be conducted. Explosions and casualties caused by insufficient attention to the fire operation, imperfect plans, improper measures (especially isolation from the oxygen source blocking blind plate), untimely or inadequate laboratory supervision occur often, and special attention should be paid.
(5) When major operations on the oxygen pipeline are performed, detailed operation plans including procedures, methods, steps, time, locations, division of labor, scopes, responsibilities, monitoring and confirmation must be formulated in advance, and only after approval and implementation by the relevant managers can they be implemented.
(6)The opening of the manual oxygen valve should be done slowly, and the operator should stand on the side of the valve to prevent accidents and injury. When the oxygen valve with a small bypass valve is opened, the small bypass valve should be opened first, so that the low-pressure section after the valve is slowly increased. When the pressure difference between the high and low pressure sections on the upstream and downstream sides of the main valve is less than and equal to 0.3MPa, open the main valve. If the oxygen valve opens suddenly and quickly between the high and low pressure sections, the low-pressure section will be rapidly filled with oxygen and compressed. The heat can not be dissipated in time due to the fast speed, forming an adiabatic compression and a sharp rise in partial temperatures, which becomes an ignition source. Assume that the oxygen pressure before and after the oxygen valve suddenly opens (the oxygen pressure before and after adiabatic compression) are P1 (0.1MPa) and P2 (1.3MPa), and the oxygen temperature before and after the oxygen valve is suddenly opened (the oxygen temperature before and after adiabatic compression) are T1 ( 30℃) and T2. The oxygen's adiabatic index K is 1.39. According to the adiabatic compression formula, the temperature T2 of the low-pressure section after adiabatic compression can be obtained as:
T 2 = T 1 (P2/P 1)(k -1)/k =622.3K (349.3 °C)
This temperature is sufficient to ignite the iron powder, rust, or organic packing of valves in the pipeline. It is dangerous to open the oxygen valve quickly. The greater the pressure difference before and after the valve is, the more dangerous it becomes.
(7) The oxygen valve that regulates the pressure or flow rate is a frequent source of accidents due to great changes in load and fast oxygen flow rate. High requirements for this kind of valve are put forward, and copper alloy or stainless steel valves are generally used with the operation of pneumatic remote control to avoid accidents and injury. Therefore, the use of non-regulating valves for regulation should be prohibited.
(8) As the oxygen pipeline or valve catches fire and spreads to the upstream side. In the event of an accident, the upstream gas source should be cut off immediately to prevent the accident from further expanding.
(9) It is strictly forbidden to use ordinary grease for the lubrication of the oxygen valve and valve stem screw, and use qualified silicone oil, silicone grease or molybdenum disulfide that does not catch fire.
(10) When the oxygen pipeline is equipped with liquid oxygen vaporization supplementary facilities, do not allow low-temperature liquid oxygen to enter the normal temperature oxygen pipeline to prevent freezing and cracking of ordinary carbon steel pipelines, violent vaporization and violent expansion of liquid oxygen (800 times of the normal pressure), a vicious explosion of overpressure caused by an increase in pressure.
(11) The oxygen in the pipeline should be dry, and the leakage of the oxygen compressor cooler should be dealt with in time to prevent the inner wall of the oxygen pipeline from rusting and causing an explosion.
This temperature is sufficient to ignite the iron powder, rust, or organic packing of valves in the pipeline. It is dangerous to open the oxygen valve quickly. The greater the pressure difference before and after the valve is, the more dangerous it becomes.
(7) The oxygen valve that regulates the pressure or flow rate is a frequent source of accidents due to great changes in load and fast oxygen flow rate. High requirements for this kind of valve are put forward, and copper alloy or stainless steel valves are generally used with the operation of pneumatic remote control to avoid accidents and injury. Therefore, the use of non-regulating valves for regulation should be prohibited.
(8) As the oxygen pipeline or valve catches fire and spreads to the upstream side. In the event of an accident, the upstream gas source should be cut off immediately to prevent the accident from further expanding.
(9) It is strictly forbidden to use ordinary grease for the lubrication of the oxygen valve and valve stem screw, and use qualified silicone oil, silicone grease or molybdenum disulfide that does not catch fire.
(10) When the oxygen pipeline is equipped with liquid oxygen vaporization supplementary facilities, do not allow low-temperature liquid oxygen to enter the normal temperature oxygen pipeline to prevent freezing and cracking of ordinary carbon steel pipelines, violent vaporization and violent expansion of liquid oxygen (800 times of the normal pressure), a vicious explosion of overpressure caused by an increase in pressure.
(11) The oxygen in the pipeline should be dry, and the leakage of the oxygen compressor cooler should be dealt with in time to prevent the inner wall of the oxygen pipeline from rusting and causing an explosion.
(12) The oxygen filter in the oxygen piping system should be cleaned regularly to remove rust and foreign matter to prevent burning and explosions. After the oxygen pipeline system is constructed and overhauled, the oxygen filter must be checked and cleaned before delivering oxygen. After confirming that there is no debris inside, the oxygen can be delivered to prevent the accumulation of rust, welding slags and other foreign matter, which may become a hidden accident hazard, ensuring the safety of delivering oxygen.
(13) The user of the oxygen pipeline shall be responsible for the safety management of the oxygen pipeline. Implement relevant safety laws, regulations, technical regulations and standards for oxygen pipelines. Establish and improve the safety management rules and regulations of oxygen pipelines of the company. Designate full-time or part-time professional and technical personnel to be responsible for the safety management of oxygen pipelines. Establish technical archives of oxygen pipelines; formulate regular inspection plans for oxygen pipelines; arrange regular inspections and repairs for auxiliary instruments and safety protection devices; conduct inspections and adjustment of hidden dangers of oxygen pipeline systems, and implement professional management of oxygen pipelines. Operators and inspectors of oxygen pipelines shall be trained in safety technology, and shall be certified for working after passing the examination.
