Term
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Definition
| Has wedge-shaped disc that is raised to open and lowered to close the valve. Used to fully open or totally close. |
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Term
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Definition
| A round disc or tapered plug-type disc that seats against a port to close the valve. Used where throttling and/or when frequent operation is required. |
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Term
| What is the purpose of the main steam stop valve? |
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Definition
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Term
| What is the purpose of the Non-Return Valve? |
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Definition
| Only allow flow in one direction. |
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Term
| Explain how you would "cut in" a boiler equipped with a non-return valve |
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Definition
| Place a fire in the boiler, Open the bypass valve, warm the steam line from the header, open the outside steam stop valve and close bypass, at 80% pressure open the stem on the non-return valve. When boiler exceeds header pressure the NRV will open and the boiler will come on line. Close the free blow drain. |
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Term
| When is more than one blow-down valve required? |
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Definition
| When it has more than 100psi |
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Term
| What is a slow opening valve? What is a quick opening valve? |
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Definition
| A slow opening valve requires more than five full turns to be fully open. A quick opening valve requires less than five full turns to be fully open. |
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Term
| Explain how you would blow down a boiler |
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Definition
| Find the true water level, have a 1/2 gauge glass or better, open cooling water to the blow down tank, open quick opening valve, open slow opening valve fully wide and close it, close quick opening valve, check level and secure cooling water to blow down tank |
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Term
| Explain the principle of operation of a bourdon tube pressure gauge |
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Definition
| A hollow bent tube, made of brass, as pressure is added it wants to straighten |
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Term
| What is a siphon? What is a snubber? |
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Definition
| Siphon: Keeps live steam out of the Bourdon tube. Snubber: separation of live steam and keeps a constant pressure |
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Term
| What is the purpose of a water column? |
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Definition
| Reduce the turbulence of water level |
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Term
| How do you blow down a water column? |
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Definition
| Open the drain valve fully wide then closing it. Remember to disable the low water cut-out if you do not want the boiler to trip. |
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Term
| How do you blow down a gauge glass? |
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Definition
| 2 valves independently, to ensure that neither connection is plugged |
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Term
| Explain how you would test a low water cutout |
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Definition
| Cut off feed supply and drain the water column |
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Term
| What is a closed feed water heater? |
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Definition
| When steam and water do not come into direct contact. |
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Term
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Definition
| Allows flow in only one direction |
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Term
| Where in the plant are you likely to find a check valve? |
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Definition
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Term
| What is a cyclone separator? |
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Definition
| Spins the steam to separate water from steam |
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Term
| Where would a cyclone separator be located? |
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Definition
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Term
| What is the purpose of a flash tank? |
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Definition
| A blow down tank that recovers heat from the blow down |
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