Oxyacetylene Set-up

ArtMetal
Bramblebush

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Posted by Valerie on September 17, 1997 at 13:18:58:

Here is a step-by-step explanation of how to properly open up the cylinders, adjust the flame and turn off the cylinders at end of day.

First check over the condition of the equipment. Are the cylinders chained to the cart (or to a wall)? Are the torch valves closed? Are the hoses in good condition?

Check that the adjusting screws on each regulator are loose. Loose means turned out counterclockwise. This releases the pressure on the diaphragm.

Open up the acetylene cylinder valve slowly so that it is one-half to one full turn open (one full twist of the wrist). The needle on the high pressure gauge should now indicate the amount of acetylene pressure in the cylinder. If no pressure is indicated - stop at this point.

Screw in the adjusting screw on the acetylene regulator (clockwise) until the needle on the low pressure gauge indicates the desired working pressure. The working pressure depends on the torch tip size.

Now bleed out the acetylene hose and check the actual working pressure at the same time. To do this, open up the acetylene valve on the torch. Let the gas flow out of the torch for a few seconds. While the torch valve is still open, look at the low pressure gauge and readjust to the desired working pressure. Close the torch valve.

Open up the oxygen cylinder valve stem just a crack. Once the needle on the high pressure gauge has stopped, open up the valve all the way. This back-seats the valve. Oxygen cylinders must have the valve opened up all the way because of the high pressure in the cylinder. There is a back-seating valve on the oxygen cylinder. This prevents the high pressure gas from leaking out through the threaded stem.

Screw in the adjusting screw on the oxygen regulator (clockwise) until the needle on the low pressure gauge indicates the desired working pressure. Note that this gauge is usually calibrated in 5-pound increments, differing from the acetylene regulator low pressure gauge.

Now check the actual working pressure of the oxygen in the same way as was done for the acetylene. If you screw it in too far and obtain too much pressure, be sure to open the torch valve before readjusting the pressure.

Lighting the torch

Open the acetylene torch valve about one-quarter turn. Light the acetylene with a spark from a "striker". Do not use matches or a butane lighter.

Adjust the flame, using the acetylene torch valve until the flame has just lost its "smoky" quality. If the flame "blows out" or blows away from the tip of the torch, the valve is too far open. If the flame jumps away from the torch tip, you have it too far open. Close the valve a bit and then slowly reopen.

With the proper shade gas welding lens over your eyes (#4-7), slowly open up the oxygen torch valve. A small, pointy flame very close to the torch tip will appear. This is called the ï¿½inner cone'. At the same time, a distinct, blue flame will begin to appear at the end of the flame. Continue to slowly open up the oxygen torch valve until the distinct blue flame has just shrunk to the same size as the inner cone. This is the proper welding flame called a neutral flame.

Proper shut-down of the cylinders

Extinguish the flame by turning off the acetylene torch valve first. Then turn off the oxygen torch valve. Close them gently because they are needle-valve and their seats can be easily damaged. It is important to do the acetylene first and then the oxygen. If the reverse order is used, carbon deposits are left in the torch every time the torch is turned off. For very large torch tips, some people turn the torch off in the incorrect manner because of the loud pop the torch sometimes makes.

Close the acetylene cylinder valve with a firm hand. Close it to the right (clockwise).

Open the acetylene torch valve again. Watch the needles on both of the acetylene cylinder gauges. When they are both at zero, gently close the torch valve again. The acetylene has now been properly bled from the system.

Close the oxygen cylinder valve. Since this valve was previously opened up all the way, it takes some time to get the valve fully closed. Close with a firm hand.

Open the oxygen torch valve. Watch the needles on the oxygen regulator valves. When both of the valves are at zero, close the torch valve again. The oxygen has now been properly bled from the system.

Wrap the hoses around the handle part of the cart. If the torch tip is still hot, be careful that it does not touch any part of the hoses. Don't wrap the hoses around the cylinders. If the hoses are around the cylinders, it is not easy to tell if the cylinders are properly chained.

Note: The cylinders should be completely shut down in this manner when you are done using the equipment for the day. If you are the last person in the area that work day, be sure to check that other cylinders are shut down properly. If you come upon cylinders that are not shut down properly, first screw in the adjusting screw until the low pressure side of that regulator indicates pressure. The open up the corresponding torch valve and wait until the needles drop to zero. Then loosen the adjusting screw again. Sometimes this happens if the cylinder valve stem was not closed tightly enough - check that too.

For additional information, obtain a pamphlet on the operation of the oxyfuel equipment from local welding gases supplier. Also avaliable is a pamphlet from CGA (Compressed Gas Association).

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