ADVANTAGE OF USING ACETYLENE INSTEAD OF OTHER FUEL IS THAT IT PRODUCES A COMPARATIVELY HIGHER TEMPERATURE AND ALSO AN INERT GAS ENVELOP, CONSISTING OF CO2 AND H2O WHICH PREVENTS MOLTEN METAL FROM OXIDATION. THE MAXIMUM FLAME TEMPERATURE IS 3200 DEGREE CELSIUS.
EQUIPMENT :-
- OXYGEN IS CONTAINED IN A BLACK COLOR CYLINDER OF 125 KG. IT HAS A BRASS/ COPPER CONNECTOR AND IS HAVING A RIGHT HAND THREAD.
- ACETYLENE IS CONTAINED IN A MAROON COLOR CYLINDER OF 21 KG. IT HAS A IRON CONNECTOR AND IS HAVING A LEFT HAND THREAD.
THIS IS THE DIFFERENCE WHICH ONE CAN SEE TO FIND OUT WHICH CYLINDER IN WHICH IF THEY ARE NOT MARKED.
- ACETYLENE CYLINDER CARRIES A POROUS MASS INSIDE, SOAKED IN ACETONE WHICH HAS A CAPACITY TO DISSOLVE 25 TIMES OF ITS OWN VOLUME OF ACETYLENE FOR EVERY ATMOSPHERE OF PRESSURE APPLIED. ACETYLENE IS COMPRESSED INTO THESE CYLINDER SO AS TO DISSOLVE IN ACETONE AND THAT IS WHY IT IS CALLED “DISSOLVED ACETYLENE”.
- NOZZLE TIP IS INTERCHANGEABLE. DIFFERENT SIZE OF TIPS ENABLE THE OPERATOR TO SELECT A SUITABLE ONE TO OBTAIN THE DESIRED SIZE OF FLAME THAT WILL SUIT THE PARTICULAR THICKNESS OF METAL TO BE WELDED.
- SIZE OF ORIFICE CONTROL THE FLOW OF GAS MIXTURE.
- SMALL ORIFICE- SMALLER FLAME, LARGE ORIFICE- LARGER FLAME.
- PRESSURE REGULATOR IS PROVIDED AT EVERY CYLINDER WHICH CARRIED A REDUCING VALVE.
- BORAX AND NaCO3 ARE THE FLUX USED.
SAFETY IN THE SYSTEM :-
- FLASH BACK ARRESTER BETWEEN REGULATOR AND HOSE.
- NON RETURN VALVE IN THE OXY-ACETYLENE TORCH.
- FUSIBLE PLUG
TYPE OF FLAMES :-
- OXIDISING FLAME– FOR BRASS.
- NEUTRAL FLAME – FOR CAST IRON, MILD STEEL, STAINLESS STEEL, COPPER, ALUMINIUM, NICKEL, MONEL METAL.
- CARBURIZING FLAME – LEAD
OXY- ACETYLENE CUTTING :-
- IT IS A CHEMICAL PROCESS IN A SENSE THAT METAL, AT THE PORTION WHERE IT IS TO BE CUT, IS ACTUALLY MADE TO OXIDISE UNDER THE ACTION OF FLAME.
- METAL TO BE CUT IS HEATED UP TO RED HEAT BY MEANS OF FLAME AND THEN A SHARP STREAM OF OXYGEN IS MADE TO IMPINGE ON TO THE HOT SURFACE TO FORM IRON OXIDE AND THUS REMOVE METAL FROM THERE.
- MELTED IRON OXIDE GET BLOWN OFF BY THE JET OF OXYGEN, THUS PROVIDING A NARROW SLIT ALONG THE CUTTING LINE.
- 6 MM DISTANCE TO BE MAINTAINED BETWEEN TIP AND METAL.
- SPARK SHOULD COME FROM OTHER SIDE OF THE PLATE.
- NORMALLY NEUTRAL FLAME IS USED BUT FOR CAST IRON, CARBURIZING FLAME IS USED AND THAT TOO AT A COMPARITIVELY LARGER DISTANCE.