Part 4 - EX-TRAFLAME®  

Our last article in this mini-series focuses on maintenance of the oxy-fuel system. As expressed in previous articles of this mini-series, downtime, expensive repair, scrappage and even personal injury can be a direct result of failure to correctly service and maintain the equipment. Setup a regular maintenance schedule to cater for the critical components and introduce a daily check-up regime for the system prior to use, this will help to protect your investment and improve safety.

EX-TRAFLAME® TORCH FOR OXY-FUEL CUTTING

Keep the torch and relating equipment clean, in good condition and in safe working order. This is the only way how to get the best cutting results. Check and test it regularly. Especially the torch, shut-off valves, flash back arrestors, hoses, gas connection etc.

IN ANY CASE do NOT use GREASE of any form and consistence.

Prove the rubber hose for leaks by immersing in water under working pressure. Possible leaks you can repair by cutting out the faulty portion and inserting a hose joiner. Worn ends cut back and the ends refix with proper hose connectors and clips. If this is not enough, replace the hose. It is recommended by norm to do pressure and leak test of the gas hoses every 3 months, provided by a specific training.

Regulators
If the regulator creeps, i.e., gas passes during release of pressure regulator screw, or builds up pressure on the low-pressure side when the torch valves are shut, exchange it at once. If gauges do not return to zero when the pressure is released, the mechanism is faulty. Fit new gauges without delay.

Cylinders are outfitted with gas-specific regulators since gases have different volumes and pressure requirements. Inspect regulator valves, seats, and threads to properly ensure they are free from oil and debris. Any contaminated parts must be cleaned and inspected by qualified service personnel. This is particularly important for oxygen valves. Oil or grease combined with oxygen is flammable – or even explosive.

Torch
Once your attachments and tips have been connected, check your entire system for leaks.

Leak test
Completely back out the regulator adjuster and slowly open the torch gas valve on the cylinder until the high-pressure gauge stabilizes. Shut the torch valve off. Watch the gauge for any drop in pressure. If no leak is evident, open the cylinder valve again and adjust the regulator to deliver 20 PSI / 1.38 bars.

Repeat the process with the fuel gas, but make sure the fuel gas regulator only delivers 10 PSI. Afterward, close the valves on both cylinders. Turn the adjusting screw a ½ turn counterclockwise. Watch both gauges for a couple of minutes, and if the readings do not change, your system is not leaking.

Open the torch valves again. If the gauge needles move, that means there is a possible leak. Stop right away and do not use any leaking equipment. Check your connections, and if a leak cannot be found you should have the equipment inspected by a qualified technician.

You can detect the leaks by using a special leak detection spray. Apply it directly onto all joints and watch for bubbles. Cure the leaking valves by tightening the gland nut.Leaks at the head nut or cutting nozzles you can remedy by cleaning the seating with a soft cotton- cloth and retighten.

Changing cylinders
A cylinder is depleted and is considered empty when it is unable to deliver fuel gas or oxygen to torch tip at the set pressure.

Also, the cylinders need to be inspected for possible leakage around the valve spindle. If leaks you can smell of gas or hear the hissing sound. Tighten the gland nut and test with some leak detection spray. If the cylinder continues to leak, contact your gas supplier.

Protecting cylinders from flashbacks:
Fit flashback arresters to both the oxygen and fuel gas hoses near to the regulators.

For long lengths of hose, fit arresters on both the torch and the regulator. The fitting of a flashback arrester is not a substitute for safe working practice. If a flashback has occurred, carefully check for damage to the torch, hoses, regulators, flashback arresters and other components. Replace parts if needed.

Flashback arrestors
The arresting element will always function. However, non-return valves and flow rates can be checked on an annual basis.

Flashbacks and backfires
Flashbacks are commonly caused by a reverse flow of oxygen into the fuel gas hose (or fuel into the oxygen hose), producing an explosive mixture within the hose. The flame can then burn back through the torch, into the hose and may even reach the regulator and the cylinder. Flashbacks can result in damage or destruction of equipment and could even cause the cylinder to explode. 

The following precautions will help to prevent flashbacks:


Check shut-off valves and regulators
The lifetime of shut-off valves depends on the correct connecting procedure during cylinder exchange. They should be checked regularly and if any damage appears, they should be exchanged immediately.

Nozzle
Do not maltreat nozzles. The correct pre-heat flame and cutting oxygen stream can only be maintained when the edge of the gas orifices is sharp.

The orifices should be regularly cleaned with special nozzle cleaners. These are readily available and are recommended as standard equipment. The cleaner should be carefully worked up and down. Do not twist. Do not force oversize cleaners through the orifices but start with a smaller size and work up to the correct one.

Equipment checks
Use a proprietary leak detecting spray or solution suitable for use with oxy/fuel systems. Do not use solutions containing grease or oils on oxygen systems. Leaking components repair or replace immediately. Remove damaged or leaking sections of hose, do not attempt to repair. Refit hose tails using crimp clips designed for that task.

Inspect all sub-contractor or third-party welding and cutting equipment before use, to ensure:


*As for all maintenance work, please use the PPE required by local law.

(Personal Protective Equipment)

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