Propane used in gas cutting is an ideal alternative fuel for acetylene. At present, the usage of propane is the largest among all acetylene alternative fuels. Propane (C3H8) is a gas with high quality and low price, which has been used in flame cutting in developed countries. Oxygen propane cutting requires oxygen purity higher than 99.5% and propane gas purity higher than 99.5%. G0 1-30 cutting torch with GKJ4 quick cutting nozzle is generally adopted.
1, preparation before cutting operation
(1) Personnel who have not obtained the qualification certificate for special operations shall not carry out gas welding and gas cutting related operations.
(2) Before cutting, it must be checked that all kinds of equipment and safety devices have been installed correctly and all kinds of equipment are working normally.
(3) Ensure that the gas pressure in the pipeline is within the normal range and has been correctly connected with the separatist regime.
(4) Check whether the cutting nozzle is defective or damaged, such as crevasse, crack and wear. If necessary, it should be replaced by qualified personnel, and all airway interfaces should be checked for signs of air leakage. Ensure that the trachea is not seriously twisted or squeezed by other heavy equipment to avoid airflow obstruction or trachea damage.
5] Before ignition, the air in the pipeline must be exhausted.
[6] In the process of cutting, the trachea must be far away from the cutting workpiece or the flame of the cutting nozzle.
2. Preparation during operation
(1) Wear personal protective equipment and observe the safety operation procedures.
(2) Handle the ignited separatist objects carefully, and don't hang them on gas cylinders, or even leave them unattended for a short time.
(3) Remove combustible materials unrelated to work from the job site to avoid fire.
(4) It is forbidden to use naked flame in the production area, and it is forbidden for personnel irrelevant to the unit to enter the production area.
3, cutting safety operation matters needing attention
3. 1 Safety analysis of gas cutting
During gas cutting, oxygen, sparks, droplets and slag are sprayed everywhere, which is easy to cause burns; Larger Mars, liquid droplets and slag can fly to a place 5 meters away from the operation point. If inflammable and explosive materials are ignited, it can cause fire and explosion. When working at high altitude, there are still flammable objects falling from a height, and the falling Mars ignites the ground. During the operation, flammable items must be far away from the operation site to prevent danger.
3.2 Safety regulations for gas cutting operations
(1) Before installing the pressure reducer at the oxygen bottle mouth, it should be blown clean for a short time to prevent the bottle mouth from being blocked.
(2) Propane cylinders and oxygen cylinders should be placed in a well-ventilated place, not exposed to the hot sun, not close to fire sources and other heat sources, and not placed under high-voltage lines and crane slide lines.
(3) When using gas cylinders, the distance from the open flame should be greater than10m. When the air volume is insufficient, it is forbidden to use open flame for heating, and only hot water or steam can be used for thawing. In addition, radioactive sources should be avoided.
(4) Before using the cutter, it is necessary to check whether the injection is correct. Open the valve of the cutter first, and then open the air valve to check the injection situation. If blockage is found, it should be eliminated. When opening the cylinder valve, you must use special handles or special tools. It is forbidden to open the valve of gas cylinder with other tools.
5] The steel cylinders used on site should stand upright on the ground or put on a special bottle rack, or put in a safer place, and be firmly fixed to prevent dumping.
[6] During gas welding and gas cutting operations, oxygen cylinders, propane cylinders and other cylinders should be kept at a certain distance (more than 5 meters) in accordance with the requirements of relevant safety management regulations. It is forbidden to use oxygen cylinders and gas cylinders together.
The primary ignition should start with propane gas, and the gas flow rate should be small. After ignition, oxygen should be turned on to adjust oxygen and propane gas, and the flame should be selected according to the work needs. When extinguishing the fire, propane gas should be turned off first, and then oxygen should be turned off.
When working in a poorly ventilated place or in a container, the cutting tool should be ignited outside first.
Levies When replacing the gas cylinder, a certain residual pressure must be maintained in the gas cylinder, the gas in the oxygen cylinder should be kept at 0. 1-0.2MPa, and the gas in the propane cylinder should be kept at 0.05 MPa.
⑽ When fire is used in inflammable and explosive production areas, the examination and approval procedures for hot work shall be handled in accordance with regulations.
⑾ After work, turn off propane gas and oxygen.
3.3 Key points of confined space operation
When flame cutting is carried out in a closed space, special preventive measures should be taken to ensure the safety and health of workers. In these places, the possibility of accumulating leakage gas is greatly increased, and the harm of smoke produced by cutting is more obvious.
(1) Implement the work permit system and comply with the safety requirements for confined space operations;
(2) a system for providing fresh air ventilation and smoke exhaust;
(3) If feasible, don't put the gas cylinder in a confined space; If necessary, the number of gas cylinders put into the confined space should be reduced as much as possible, and whether there is leakage should be strictly detected, and it should be moved out when the work is stopped.
4, equipment inspection and maintenance
4. 1 Inspection of equipment before use
Before each cutting operation, it is necessary to check whether all equipment and safety devices are installed correctly and in good working condition. The pre-use inspection of the equipment includes:
(1) Ensure that each gas cylinder is equipped with the correct type of pressure regulator and connected with the cutting torch correctly;
⑵ Check whether the trachea is defective or damaged, such as crevasse, crack and wear. If necessary, it should be replaced or repaired by professionals;
(3) Use a leak detector or soapy water to check whether there are signs of air leakage at all airway joints;
(4) Ensure that the air pipe is placed in such a way that it will not be severely buckled or run over by other heavy equipment, so as to avoid air flow obstruction or air pipe damage.
4.2 General inspection and maintenance of equipment
In addition to pre-use inspection, the condition of all equipment should be checked regularly. The frequency of inspection depends on the use of the equipment and the working environment.
The erosivity of the environment, etc. The faulty or damaged equipment should be stopped immediately, and the technicians should repair and eliminate the fault. The regular inspection of equipment shall include the following contents:
(1) Whether there is air leakage inside the pressure regulator;
2. The pressure instrument is operating normally;
(3) Check whether there is internal air leakage and nozzle blockage in gas cylinders, pipelines and cutting torches. If the above phenomena are found, eliminate them in time.
(4) Check whether the valve switch of the equipment is flexible and blocked.
5. Emergency procedures
Emergency procedures should be established so that workers can follow them when faced with danger. The program should include: setting guide signs to explain to workers when and how to operate.
Stop working and move to a safe place, or even evacuate the workplace. The following are some emergency situations and emergency measures that may be encountered during gas welding and flame cutting:
If there is a small fire in the production area, you can try to control the fire with fire extinguishing equipment, but you can only try to put out the fire without causing physical damage;
When the fire is fierce, on the one hand, put out the fire, on the other hand, start the fire alarm and ask the fire department for help.
If the fire involves gas cylinders, it should be handled by firefighters. However, if circumstances permit, the following preliminary measures can be taken as appropriate:
(1) Spray the cylinder with water to cool it, but this step can only be carried out under safe conditions;
⑵ Close the cylinder valve to control the fire, but this step can only be carried out under safe conditions;
(3) Start the fire alarm or use other methods to evacuate people in the building.
(4) Don't try to move cylinders that are already on fire or are affected by the heat close to the fire. Even if the cylinder seems to have cooled down, moving it can be dangerous.
6. Safe storage and handling of gas cylinders
Gas and oxygen are generally stored in gas cylinders at high pressure, and propane, hydrogen, natural gas and other gases are combustible gases. Therefore, the safe methods for storing and handling gas cylinders should include the following points:
(1) When receiving the gas cylinder, make sure that the gas cylinder has the correct color and label, and there is no sign of air leakage.
⑵ Store the gas cylinders in a cool and ventilated place, away from heat sources and fire sources; The gas cylinders in use should also keep a certain distance from the welding and cutting positions.
(3) When storing or using, the gas cylinder should be placed and firmly fixed on a solid bracket.
(4) Minimize the storage quantity of gas cylinders within the practical scope and meet the requirements of relevant laws.
5] Handle the gas cylinder carefully, and don't throw or collide with the gas cylinder.
[6] If the gas cylinder is found damaged, notify the supplier immediately. When moving gas cylinders, specially designed wheeled trolleys should be used, and the gas cylinders should be firmly tied to the trolleys to prevent damage to the gas valves and reduce the risk of injury.
7, equipped with personal protective equipment
(1) eye protection
Eye mask, glasses, mask, etc.
(2) Protective clothing
The main function of protective clothing is to protect workers from being burned by flame, hot slag or workpiece. Appropriate protective clothing should be selected according to the workload, nature and location of welding and cutting work, including masks, aprons, gloves, safety shoes and shoe covers. Prepare corresponding protective clothing according to actual work needs.
8. Guidance and training
All personnel involved in gas flame cutting operations should receive comprehensive guidance and training on work safety and health, whether in normal operation or emergency response, which should appropriately include:
(1) Danger of gas flame cutting;
(2) How to select and operate related equipment;
(3) the function and limitation of safety devices;
(4) How to choose ventilation system and personal protective equipment related to operation and its limitations;
5] safety operation procedures;
(6) Emergency procedures.