REGULATORS

The oxygen regulator has a right-hand thread and   the acetylene a left-hand thread. This prevents installing the regulators on the wrong cylinders. The regulators reduce cylinder pressures to a controlled and useable amount. Figs. 13-25 and  13-26 illustrate typical regulators. Note the cylinder and hose fittings. The left-hand gauges read cylinder

pressure. The right-hand gauges indicate tip operating pressure. Tip pressure is varied by adjusting the handles.

 Before attaching regulators to cylinders, crack  (open slightly) the valve on each cylinder a small amount for a second to blow out dust or other foreign material. Do not crack the acetylene near any open flames or near a welding operation. Attach the   regulators to their respective cylinders. Tighten   gently. CAUTION! Never use oil on regulators. Do not handle gas welding equipment with oily or greasy hands. Do not wear oil soaked clothing. Oil, in the

presence of pure oxygen, becomes highly flammable. Back out the pressure control handle on each regulator (counter clockwise) until free.

Attach hose

Attach hoses to the regulators. The acetylene hose is normally red and the oxygen black. Acetylene fittings are left-hand threads while oxygen fittings are right-hand. When using the equipment, keep hoses away from hot sparks, flame, oil, and grease. Avoid kinking, and coil the hoses when finished working

Attach torch mixing handle

The torch mixing handle should be attached to the hose end. Do not over tighten either mixing handle or regulator end hose connections. Where rubber 0-ring seals are used, hand tightening is sufficient Note the oxygen and acetylene mixing valves in fig. 13-27.

Adjusting gas pressure

After installing the desired tip, MAKE SUR\ THE REGULATOR PRESSURE CONTROL

HANDLES ARE BACKED (COUNTERBLOW WISE) COMPLETELY OFF. THE CYLINDER VALVES MAY THEN BE OPENED – VERY SLOWLY. Open the ACETYLENE VALVE about ¼ to 1/2 TURN. Open the OXYGEN valve ALL

THE WAY to prevent leakage around the valve

Stem .Leave the ACETYLENE WRENCH in place   On the valve to facilitate an emergency shutoff— if  required at any time.  SHUT the ACETYLENE mixing valve. OPEN the   oxygen mixing valve. Turn the OXYGEN regulator handle in (clockwise) until the desired working

pressure is obtained (read low pressure gauge)  PURGE (clear the hose of air or other gases) the  Oxygen  hose line by allowing oxygen to flow from the  Hose momentarily. SHUT off the oxygen mixing OPEN the acetylene mixing valve (oxygen valve Off ) and adjust acetylene regulator to desired pressure .Following purging, close acetylene mixer NOTE| Purging lines is very important. Failure to do so can allow acetylene to enter the oxygen hose and  vice versa. This, of course, creates a combustible mixture inside the hose and can cause a flashback fire burning inside hose).

Lighting torch

OPEN the acetylene mixer valve a small amount   while operating a spark lighter in front of the tip. KEEP THE TIP FACING IN A SAFE DIRECT- TON. HAVE YOUR WELDING GOGGLES IN POSITION. See Fig. 13-28.

When the acetylene ignites, adjust the flame until It is hovering about 3.0 mm from the tip, A, Fig. 1329. Immediately open the oxygen valve and adjust the flame. By starting with a carburising flame, B, and slowly closing the acetylene valve, C, a neutral flame may be acquired, D. Watch the yellowish acetylene feather to tell when the neutral flame is

reached, Fig. 13-29.

Shutting oft torch

Close the acetylene mixer valve. The oxygen will  blow out the flame at once. Then, shut off the oxygen mixer valve. When using this technique of shutting off the flame, make certain the acetylene valve is not leaking. If you will be welding again within a few minutes,  hang the torch up out of the way. If it will be some time before the torch is needed, drain the lines.

To drain the lines, shut off both the acetylene and oxygen cylinder valves. Open one mixer valve at a time until the low pressure gauge indicates there is no pressure left in that line. Back off the regulator adjuster handle. Close the mixer valve. Repeat on the other line.

Lighting cutting torch

Set regulators to give required pressure. Close the   cutting attachment oxygen valve. Open the mixer oxygen valve all the way. Open the acetylene mixer valve and light the torch. Open attachment oxygen valve and adjust preheat flames to neutral. Depress oxygen jet lever and if preheat flames are altered, readjust. These directions are for a  cutting   attach- mint - shown in Fig. 13-12. If another cutting torch   is used, follow the manufacturer’s instructions.

BASIC SAFETY RULES FOR OXYACETYLENE

EQUIPMENT

1.

Wear protective goggles.

2.

Wear protective gloves and clothing.

3.

Keep all oil and grease away from equipment.

4.

Never use equipment with greasy hands or when

wearing greasy garments.

5.

Have ample ventilation.

6.

Do not cut, weld, or braze fuel tanks.

7.

Do not work in an explosive atmosphere

8.

Always have a fire extinguisher on the job.

9.

Open cylinder valves slowly

10.

Maintain good hoses and fittings.

11.

Purge lines before lighting.

12.

Never use defective regulators.

13.

Inspect hose for damage following a flashback.

14.

Never try to repair hose with tape. If a hose leaks, discard it.

15.

Stand to one side of regulators when opening

cylinder valves.

16.

Open acetylene cylinder valve no more than one turn.

17.

Never use acetylene at pressures exceeding 100 kPa.

18.

When adjusting either oxygen or acetylene pressures, make certain the other mixer valve is closed. This will prevent flashbacks.

19.

Hold torch in a safe direction when lighting.

20.

Know what you are cutting or welding. Some coatings produce deadly gases when heated. CAUTION! There are many more specific safety rules. Study a booklet on safe practices from one of the companies handling gas welding equipment. Have an experienced operator assist you until you have mastered setting up, lighting, and using equipment safely.

ARC WELDING

Arc welding utilises the intense heat  (3,000-5,000°C) generated by an electric arc between  the end of the welding rod and the work. Both the base metal and filer rod quickly reach the fusion state. As the work puddles, the rod end melts and flows into the molten base. metal. The arc force actually causes the molten globules of rod metal to travel through the arc to the puddle.’ This allows the arc welder to be used for overhead welding. See Fig. 13-30.

 Polarity

 Two common terms used in DC arc welding arc  STRAIGHT POLARITY and REVERSE POLARITY. Reverse polarity means the current is travelling from the work, up through the arc to the rod and rod holder. Straight polarity means the current travels from the rod holder (often called a stringer) through the rod, across the arc, and to the work. For a straight polarity hook-up, merely plus (unless a polarity switch is used) the rod holder cable into the hole marked with the straight (negative) symbol (-). For a reversed polarity hook-up, plug the rod holder cable into the crossed (positive) symbol (+).

Type of machine

Basically, an arc welding machine may be an AC  (alternating current) or DC (direct current) machine. Combination AC-DC machines are also available. The AC or AC-DC machine is generally a power transformer that alters the incoming 240-415 volts (utility line voltage) to a low voltage, high amperage current for welding. A typical AC-DC machine is

pictured in Fig. 13-31. The DC machine is usually motor (electric or piston engine) driven. Both types have certain advantages and disadvantages. Machines are rated by maximum output in amperes. The higher the output, the heavier welding the machine will perform.

Caution & Disclaimer

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All items and articles contained in this website have been
published in good faith and neither the website owner or
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accuracy of any information or statements contained herein.
I (r g & m a hopley) the author and editor of this website hereby disclaim 
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otherwise arise.

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