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23 Cards in this Set
- Front
- Back
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Oxygen (O2) is a colorless, odourless and tasteless gas that supports combustion.
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When the oxygen cylinder is filled, the gas is compressed to aproximately 15,000 kPa (2175psi) at 21 degree Celsius (70 degree F).
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When a cylinder requires refilling, it should be marked MT with chalk or soapstone.
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The oxygen valve must always be fully open when using oxyacetylene equipment.
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Acetylene (C2H2) is a flammable gas made from calcium carbide and water.
What is the maximum safe working and critcial point pressure? |
105 kPa or 15 psi
The critical point for acetylene is 28 PSI and 21°C. |
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Acetylene cylinders must always be used in an upright position.
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Fusible plugs are installed in the cylinder to allow a controlled release of acetylene in the event of a fire.
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The acetylene valve must NOT be fully open when acetylene is being used.
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Pressure regulators are used on both the oxygen and acetylene cylinders. They are required to reduce cylinder pressure to a usable working pressure.
What are types of regulators? |
- Single stage
- Two stage |
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Oxygen hose:
- right handed thread - green Acetylene: - left handed thread - annular groove cut in the hexagonal of fitting - red Minimum burst pressure? |
400 psi (2760 kPa)
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One-way check valves prevent mixing of the acetylene and oxygen in the hoses or regulators by allowing a flow of gas in one direction only.
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What are the types of flame?
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1. Acetylene flame (800°C or 1472°F)
2. Carbonizing flame (3150°C or 5700°F) 3. Neutral flame (3230°C or 5850°F) 4. Oxidizing flame (3480°C or 6300°F) |
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A backfire is a loud snap or pop and the flame goes out.
What cause backfires? |
- too little gas pressure
- obstruction of gas flow by holding the torch tip too close to the work - loose or faulty seat connections between the tip and mixer - a dirty tip - a hot tip |
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Flashback occurs when the flame goes inside the torch and continues to burn.
What causes flashback? |
- Grossly unequal pressures
- Mildly unequal pressure plus an obstruction - Faulty manipulation of valves - Failure to purge each line individually before lighting the torch |
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Shade #4 or #5 is recommended for cutting and #5 or #6 is recommended for general welding.
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The steady rest on a stationary or pedestal grinder shall not be more than 3mm (1/8") clearance from the grinding wheel.
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The rpm rating of a grinding wheel or stone should match or exceed the rpm rating of the grinder.
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a WHMIS label indicates the contents of the cylinders.
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The valve on an oxygen cylinder has a right-hand (RH) thread.
Acetylene? |
Acetylene cylinder valves has a left-hand (LH) thread.
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Oxygen cylinder valve is a double seated valve.
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What does the occupational health and safety code states?
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An employer must ensure that on each hose of an oxygen-fuel system, a back-flow prevention device is installed at the torch end.
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The torch, torch handle, provides fine adjustment of gases by using torch valves.
what is torch valves? |
The valves on the torch handle are needle valves that allow fine, individual adjustments of oxygen and acetylene flow.
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Ultraviolet rays cause burning and blistering of the eyeball.
What can infrared rays cause? |
Infrared rays can cause retina damage and are a known cause of cataracts.
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