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27 Cards in this Set
- Front
- Back
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force |
Push or a pull upon an object F= P * A |
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Pressure |
force applied to surfacearea of an object per unit area P= F/A |
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kpa & psi at atmospheric pressure |
101.3 kpa 14.7 psi: 1 kgf/cm2 (unit) |
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1psi = kpa? |
1psi = 6.895 kpa |
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1 lbf = N? |
1 lbf = 4.45N |
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1 in^2 = m^2? |
1 in^2 = .0006452 m^2 |
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1 in =cm? |
1 in = 2.54 cm |
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hydraulic jack |
p1=p2 F1/d1 sq = F2/d2 sq |
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reciprocating pump |
F1 = F2 P1*D1sq = P2 * D2sq |
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1m = ft? |
1m=3.28ft |
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unit of mass = slug (imperial) gravity=? |
gravity in slug = 32.2 ft/s sq |
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1psi= ?inch of water |
1psi= 27.65 inch of water= 2.3 ft of water |
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1kpa = mm of water? |
1kpa= 1/9.81= .102m= 10.2cm= 102 mm of water |
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1m = kpa? |
1m= 9.81 kpa |
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1 psi = inch of hg? 1kpa= mm of hg? (mercury) |
1psi= 2.034 " of hg 1kpa= 7.5 mm of hg |
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different pressure measuring instruments? |
-manometer- accurate, used for low pressure -Pressure guages- reasonable accuracy, measures wide range of pressure -deadweight tester- very accurate, used when pressure too high for manometer - transmitters- accurate, use diff elements to generate instrument signal |
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Manometer |
a- U-tube b- Inclined tube: low presure , HIGH accuracy,(used for windbox, furnace , flue gas press) c- Well type: max 20 psi, 41" high |
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Bourdon tube presure guage |
'C' hollow tube 105 kpa to 7000 000 kpa |
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What are the adjustments need to be made to calibrate a bourdon guage |
-Zero: opening guage's pressure connection to atmospheric pressure (gear or zero adjustment screw) -Span: 100% pressure is applied, set by loosening the span adjustment screw and sliding link . -Linearity: when gauge is correct at 0 & 100% but not at 50%, can be adjusted loosening the screws on the plate holding quadrant. |
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three major factors that result in damage |
-Vibration: to limit it, shock reducing mount can be used -Pulsation: pressure can vary sharply, can be reduced by using needle valve or snubber. -Dirt: an isolating diaphragm can be used to prevent dirt from getting in. or separating device that'll filter dirt. |
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helical element |
4 or five turns, more turns causes tip to move further for a pressure change. can be transfer to a pointer or transmitter 1kpato 70 000 kpa |
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Spiral element |
spiral shape, used for pneumatic recorders 70 to 30 000 kpa |
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spring and bellow element |
chamber that can expand and contract under pressure changes. causes movement of linkage which is connected to transmitter or pointer or recorder 1 kpa-300 kpa |
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diaphragm element |
measurement of low pressure (furnace draft) stretch motion is transferred to a pointer through links
0-100 kpa |
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inverted bell elemet |
sensitive low pressure element measure boiler drum level, furnace presssure. 1kpa to 3500 kpa |
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steam pressure recorder |
sensing element, connected to bellows change in pressure on bellows is proportional to movement of pen on recording chart |
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Dead weight tester |
used to calibrate pressure gauges and transmitters when pressure ranges is high |
