Usage tips for oxygen cylinder riveting machines
The oxygen cylinder neck riveting machine is a specialized key equipment used for permanently and airtight riveting and connecting the shoulder of seamless steel gas cylinders with the metal seat (valve seat) of the cylinder valve. Its operation is highly specialized and directly related to the safety of gas cylinders. The following content is based on professional practice and is for reference by trained and certified personnel only. Unqualified personnel are strictly prohibited from operating.
Core principles and safety warnings
Qualification requirements: Operators must undergo specialized training and pass the assessment for the manufacturing and inspection of special equipment, and be familiar with the structure of gas cylinders and safety regulations.
Absolute oil prohibition: All components that come into contact with oxygen (bottle mouths, valve seats, molds) must undergo strict degreasing and cleaning before assembly to ensure there is no grease or organic contamination.
Pressure vessel awareness: The object of operation is a high-pressure vessel component, which requires rigorous treatment.
The status of the gas cylinder riveting machine: Ensure that the machine is in good maintenance condition, and that the pressure, stroke, and mold alignment all meet the requirements.
I. Preparations before Operating the gas cylinder riveting machine
Component inspection and cleaning
Bottle body: Confirm that the bottle body has completed the hydrostatic test and internal treatment. The bottle mouth thread is intact and undamaged, and has been thoroughly degreased and dried.
Valve seat (metal seat) : Check its dimensions, threads and sealing surface to ensure it is absolutely clean and oil-free.
Sealing gasket: Use materials compatible with oxygen (such as polytetrafluoroethylene, annealed red copper gasket), and check its integrity.
Equipment inspection and calibration
Mold matching: Select the correct upper and lower riveting molds based on the specifications of the gas cylinder (nominal working pressure, cylinder mouth type). Check if the mold has any cracks, wear or oil stains.
Centering adjustment: This is one of the key techniques. The equipment must be adjusted to ensure that the axis of the gas cylinder mouth is strictly aligned with the axis of the pressure head of the riveting die. Slight deviations can lead to uneven riveting, poor sealing or damage to the threads.
Pressure and stroke setting: Set the riveting pressure and working stroke of the hydraulic or pneumatic system according to the process regulations. Insufficient pressure can lead to an insecure connection, while excessive pressure may cause deformation of the bottle mouth or failure of the sealing gasket.
No-load test run: Start the equipment and perform a no-load cycle to observe whether all actions are smooth and accurate without any abnormal sounds.
Ii. Operating Procedures and Core Skills of Gas Cylinder Riveting Machine
Assembly and Positioning
Place the clean sealing gasket into the sealing groove at the bottle mouth.
Screw the clean valve seat into the bottle mouth thread. Tip: First, screw it in by hand to ensure the thread is smooth and avoid misalignment. Then, use a special wrench to pre-tighten according to the torque specified by the process to ensure that the valve seat and the gasket are initially in contact. The preload torque is a key parameter and must comply with the provisions of the process card.
Lift or place the assembled gas cylinders steadily onto the worktable of the necking machine, ensuring that the cylinder bodies are vertical and the cylinder mouths are precisely fitted into the positioning sleeves of the lower mold.
Riveting process
Start the equipment and let the upper press head (punch) descend.
Observe the initial contact: When the upper mold touches the upper end of the valve seat, observe whether the contact is uniform. If there is any deviation, stop immediately and re-align.
Perform riveting: Continue to apply pressure. The specific profile of the upper mold evenly rolls, rolls, and plastically deforms the metal cylinder wall (or the metal of the bottle shoulder) extending above the valve seat outward and downward, causing it to tightly wrap and lock onto the specific groove or chamfer at the bottle mouth, forming a permanent mechanical seal band.
Holding pressure: After reaching the set pressure or stroke, maintain the pressure for several seconds to fully stabilize the metal deformation.
Key points of process monitoring (Core skills) :
Listen to the sound: The normal riveting process makes a smooth and dull sound. The appearance of sharp friction or impact sounds may indicate poor alignment or the presence of foreign objects.
Observe the deformation: Check whether the metal rolled edge forms a continuous, uniform and smooth circle. There should be no cracks, folds or asymmetry.
Control parameters: Closely monitor the pressure gauge readings to ensure they are within the range specified by the process. The end of the journey should be in line with expectations.
Iii. Inspection and Verification after the operation of the oxygen cylinder riveting machine
Visual inspection
The riveted rolled edge should be full and continuous in shape, with no visible defects.
Use an optical magnifying glass to check if there are any micro-cracks at the edge of the rolled edge.
Check whether the bottle mouth thread has been damaged in any way during the riveting process.
Dimension inspection
Use a dedicated gauge or caliper to measure the key dimensions of the rolled edge (such as height, outer diameter, and thickness) to ensure they meet the requirements of the drawing.
Air tightness test (crucial final verification) :
Gas cylinders that have been riveted must undergo a gas tightness test.
Immerse the gas cylinder in a water tank or apply leak detection fluid. Then, introduce clean compressed air or nitrogen at the specified pressure and hold the pressure to check if there are any bubbles at the riveting points.
Any leakage indicates a failed riveting, and the gas cylinder must be scrapped or evaluated by a senior technician as to whether it can be repaired (usually scrapped directly).
Iv. Maintenance and Care Tips for Gas Cylinder Riveting Machines
Mold maintenance: Clean the mold after each use and regularly check for wear and tear. Apply anti-rust oil when storing (but it must be thoroughly degreased before use!) .
Equipment cleaning: Keep the workbench, positioning sleeve and other areas clean and free of metal shavings.
Parameter recording: For each batch of gas cylinders, key riveting parameters (pressure, stroke, operator, etc.) are recorded to achieve traceability.
Summary
The essence of using an oxygen cylinder riveting machine lies in "precision" and "cleanliness".
Precision: Accurate centering, precise parameter control, and meticulous process observation.
Clean: The absolute oil-free and pollution-free requirements that run through the entire process.
The operator must possess the spirit of craftsmanship and regard each riveting as the production of a safety-critical component. Ultimately, a 100% qualified rate of air tightness is the only hard and fast criterion for testing whether the operation skills are in place. All operations must strictly follow the process regulation documents of this unit, which are the legal basis above all oral experience. Shot blasting operations are carried out on gas cylinders.