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20 Cards in this Set
- Front
- Back
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What materials form the bases of the 3 types of hydraulic fluids?
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1. Vegetables
2. Minerals 3. Phosphate-esters |
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What colors denote mineral-based and phosphate-ester based hydraulic fluid?
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Mineral = RED
Phosphate ester = light PURPLE |
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What are the results of exposing lacquers, oil-based paint, plastic resins, and vinyl compounds to phosphate-ester based hydraulic fluid?
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The materials will be damaged and/or softened, or the paint will peel.
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Name several sources used to develop hydraulic pressure.
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1. hand pumps
2. engine-driven pumps 3. electrically driven pumps |
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What would cause the bypass valve in a hydraulic filter to open and allow unfiltered fluid to circulate in the system?
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A clogged filter element.
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Describe several methods of pressurizing a hydraulic reservior.
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1. Engine bleed air
2. system pressure acting on a small piston in the reservior. 3. using variable-displacement hydraulic pumps |
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what feature prevents engine damage if an engine-driven hydraulic pump seizes or is overloaded?
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A shear section in the driveshaft will break, disconnecting the pump from the engine.
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Describe the purpose of a pressure relief valve.
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Pressure relief valves limit the maximum pressure produced by the pump, thereby preventing failures of the system components.
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Engine-driven pumps deliver the output fluid flow in what 2 forms?
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1. Constant volume
2. Variable volume |
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Describe the operation of a gear type pump.
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2 meshed gears, driven by a power source, rotate in a housing. Inlet fluid is carried around the outside of the gears and delivered to the outlet side as the gears rotate.
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Describe the purpose of a pressure regulator.
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Pressure regulators manage the output of the pump to maintain system pressure.
They allow the pump to be unloaded so it turns without significant resistance |
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What is the device that is used in some systems to supplement the pump output during periods of high demand?
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An ACCUMULATOR
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What are the 3 different type of accumulators?
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1. piston
2. diaphragm 3. bladder |
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What safety precautions must be taken prior to disassembling an accumulator?
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release all of the air or PRELOAD
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When a hydraulic unit is replaced, what precautions should be taken to avoid contamination of the system?
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All lines should be capped or plugged immediately after they are disconnected.
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What types of components or systems are pneumatically operated in some aircraft?
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1. landing gear
2. brakes 3. flaps 4. other mechanical actuators |
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Name several sources of pneumatic power.
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1. storage bottles
2. engine bleed air 3. engine-driven compressor 4. vane type pump |
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what happens to excess pressure in a pneumatic system?
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a relief valve vents it overboard
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What is the function of a restrictor in a pneumatic system?
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To control the rate of flow of the airflow
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What are the reasons for periodically purging a pneumatic system?
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To remove moisture and contaminants
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