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32 Cards in this Set
- Front
- Back
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How is tubing designated?
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By actual outside diameter.
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What drives a gauge?
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A bourdon tube.
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What is adsorbent filtration used for?
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To remove additives from the system.
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What's the difference between simplex and duplex strainers?
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Simplex requires system isolation to clean. Duplex does not.
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How is a direct acting diaphragm control valve activated?
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Air acts on top of the diaphragm.
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How is piping designated?
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Nominal sizing.
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What material is used for salt water piping?
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Copper-nickel, monel, or corrosion-resistant steel.
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What is the purpose of absorbent filtration?
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Filter particulate from the system.
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What are rubber or neoprene gaskets used for?
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Medium temperature/pressure systems.
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What are metal gaskets used for?
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High pressure/temperature systems.
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What are cork and paper gaskets used for?
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Low pressure/temperature systems.
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How is a reverse acting diaphragm control valve operated?
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Air pressure acts on the bottom of the diaphragm.
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How are hoses designated?
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By actual inside diameter.
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What are the four purposes of valves?
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1. Limit flow to one direction.
2. Start or stop flow. 3. Throttle flow rate. 4. Re-direct flow. |
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What are the pros and cons of using a globe valve?
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Pro: can be throttled.
Con: change in flow direction causes turbulence and a pressure drop. |
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What are the pros and cons of the gate valve?
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Pro: no changes in flow direction, causing minimal pressure drop.
Con: cannot throttle. |
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What are some features of the butterfly valve?
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1. Used in low pressure/temperature systems.
2. Rubber seat. 3. Can be used to throttle. 4. Provides minimal flow resistance. 5. Compact and inexpensive. |
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What are some features of ball or plug valves?
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1. Used in high pressure, low temperature systems.
2. Minimal flow resistance. |
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What causes a relief valve to trip open?
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If the pressure over the plug's surface area is greater than the spring force.
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What are some features of the pinch or diaphragm valve?
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1. Used in low temperature/pressure systems.
2. Used for corrosives. 3. Uses a diaphragm to stop flow. |
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What do reducing valves do?
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Throttle system flow to maintain a specific system pressure.
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What is the main component of both reducing and relief valves?
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An adjusting spring.
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If spring tension is increased, what effect does it have on system pressure, and why?
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If spring tension is increased, it raises the amount of pressure required to open the valve, which raises the system's temperature.
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What keeps a flushometer closed?
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A bypass orifice allows the inlet water to fill the upper chamber, equalizing the force on the diaphragm.
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How is a flushometer activated?
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The handle trips the valve, which drains the upper chamber, allowing the inlet pressure to lift the diaphragm off the seat.
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If the adjusting spring breaks on a reducing valve, what happens and why?
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With no spring force, there is nothing to counter the high pressure flow, so the valve shuts, relieving pressure on the piston. This allows the piston to rise due to the force of the main valve spring, shutting the valve.
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If the controlling diaphragm in a reducing valve breaks, what happens and why?
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With nothing to counter spring force, the valve opens completely, allowing high pressure to depress the piston. The pressure on the piston overpowers the main valve spring and opens the valve.
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What is the weak spot of the BANJO fitting?
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The hollow bolts.
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What is the key component of a pressure fitting?
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The ferrule.
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Where are flared copper tubing connections used?
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Low pressure systems.
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In what systems is graphite packing used?
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High pressure/temperature steam.
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What kind of packing is used in low pressure/temperature systems?
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Teflon coated flax braid packing.
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