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Preventing regulator burnout when welding
22 November 2013
Oxygen regulator fires fortunately do not occur frequently in the welding industry, but when they happen, the damage to property and personnel can be devastating. Regulator burnout can happen to the most experienced welder if proper safety practices are not followed.
An operator in a hurry, a safety step overlooked, can lead to an accident. Because the causes of regulator burnout are not always clear, it may be impossible to completely eliminate this safety hazard, but the damage and potential injury can be contained by following welding safety procedures and using advanced regulator technology.
Regulator fires happen when high pressure oxygen passing through the intake valve comes in contact with contaminants on the valve. The high pressure passage of the oxygen through the narrow valve creates heat. Any flammable material on the valve, including dirt, oil, grease or other hydrocarbons, can ignite under this heat. The resulting fire often triggers an explosion, turning parts of the regulator into high-temperature projectiles.
Necessary safety procedures
To avoid this problem, the following welding safety procedures should always be followed:
1. Crack the oxygen cylinder valve before you attach the regulator. To do this, stand to one side or to the rear of the cylinder outlet. Open the cylinder valve slight for an instant and then close it. This should clean accumulated dust and dirt from the valve.
2. Use only oxygen regulators to control oxygen supply. Switching regulators from non-oxygen use to oxygen use can introduce contaminants into the system. Be sure the valve is clean and free of grease and oil. Never use an oxygen regulator for other gases.
3. Before opening the cylinder valve, be sure the oxygen regulator pressure-adjusting screw is released. To do this, rotate the screw counter clockwise until it turns freely.
4. Stand to one wide whole opening the oxygen cylinder valve. Open the valve as slowly as possible until the high pressure gauge reaches cylinder pressure. Never open the cylinder valve suddenly, as sudden surges of high pressure can cause a blow out.
Oxygen regulators provide protection
Oxygen regulators also provide further protection from regulator burnout.
When in search of an oxygen regulator that is both accurate and safe, consider these factors:
Look for a regulator body that is machined from solid brass bar stock, not made from forgings. The bar stock provides a thick wall that helps contain a burnout and keeps internal body cavities to a minimum. Small cavities limit the amount of gas that can accumulate in the body and contribute to the seriousness of an oxygen fire. A bar stock design also adds to the durability of the regulator.
A regulator with a small cavity design is preferred, as such a design sharply diminishes the intensity of any fire that might enter from the inlet connection, reducing the possibility that the regulator will explode.
Look for an oxygen regulator that uses substantial baffle plates which will protect the diaphragm and keep it away from the main gas stream. The diaphragm should not be directly exposed to hot gas or fire that could destroy it. Additionally, small bleeder holes in the baffle plate will allow the diaphragm to respond to demand for greater or lesser amounts of gas supply. This baffle system prevents the fire from reaching the chamber, where the potential for an explosion is the greatest.
Also, consider a regulator with a small quantity of seat material, which lowers burnout intensity should one occur. Limiting the amount of synthetic material in a regulator reduces possible fuel that could contribute to a fire.
When heavier diaphragms are used in regulators, the rubber can shrink in sub-zero temperatures, resulting in leakage between the body and cap. Regulators that incorporate a fabric-reinforced neoprene diaphragm are a better choice as they shrink less.
Regulator fires can occur when gauges are accidentally used for the wrong types of gas. Such misuse increases the potential for contamination of the regulator. Use of a contaminated regulator with high-pressure oxygen can result in a regulator burnout. To reduce or eliminate the likelihood of this occurring, look for regulators that are color coded and clearly labeled for their correct usage.
Oxygen regulators are sensitive instruments and should be treated accordingly. Regulators should be handled with care, as they are easily damaged.