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15 Cards in this Set
- Front
- Back
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The device used to maintain a constant pressure throughout apneumatic control system is called aa) reducing valveb) control regulatorc) pneumatic valved) balancing valvee) none of the above |
a) reducing valve |
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Pneumatic controllers are divided into two basic classesa) direct and indirectb) off/on and proportionalc) positive and negative actiond) bleed and non-bleede) reset and gain |
d) bleed and non-bleed |
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A pneumatic control systema) uses a sensing device to change pressures in the controllineb) requires an intermittent air supplyc) always uses pressure actuated final controlled devicesd) is not used to control air flow for ventilatione) is seldom used to control humidity |
a) uses a sensing device to change pressure |
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In a non-bleed type controller the device that senses achange in room temperature is called aa) sensing valveb) bellowsc) set point gaged) temperature switche) feedback switch |
b) Bellows |
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In a self-contained control system the energy for operationis provided bya) electricityb) air pressurec) the reaction of the sensing deviced) a bellowse) a bleed type nozzle |
c) the reaction of the sensing device |
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Parallel blade dampers are usually used fora) changing the direction of the air flowb) varying the amount of air flowc) turning the air flow on or offd) proportional operatione) mixed air control (outside and inside air) |
c) turning the air flow on or off |
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An example of final control device for a heating system is aa) slide-gateb) pumpc) fand) set of louverse) all of the above |
e) all of the above |
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The most common type of damper operator is aa) slideb) rampc) bellowsd) pistone) pilot positioner |
d) piston |
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An example of an auxiliary device for a pneumatic controlsystem would be aa) reducing valveb) three way air valvec) damperd) pumpe) bellows |
b) three way air valve |
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A pneumatic relay can also be called aa) selector switchb) air reservoirc) bleed type controllerd) cumulatore) pneumatic-electric switch |
d) cumulator |
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When the control pressure in a pneumatic controller is either at maximum or minimum without any intermediate steps, the control is: a) proportional b) on-off c) proportional plus reset d) proportional plus rate |
b) on-off |
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The piston is sealed to avoid air leakage in a piston type damper operator by using: a) highly machined surfaces b) composite "O" rings c) rolling diaphragm d) carbon rings |
c) rolling diaphragm |
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When a pneumatic controller increases the control pressure on an increase in the controlled condition, it is called: |
direct acting |
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When a pneumatic controller decreases pressure on an increase in the controlled condition, it is called: |
Reverse Acting |
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A pneumatic control system consists of four essential parts: |
- an air compressor with storage tank, filter and reducing valve - air piping and tubing forming the air distribution system - controllers, such as thermostats and humidistats - controlled devices, such as convector valve, zone valves and damper operators |
