Hydraulic Final #2 Flashcards by Jared Byrne

Name a non-positive displacement pump?

Centrifugal

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Formation and collapse of air bubbles

Cavitation

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What are 2 common causes of cavitation?

1) Restriction on inlet side of pump
2) Oil is too viscous

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T or F
True pump cavitation stops at the pump?

True

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What is false cavitation?

Psuedo-cavitation

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What is caused by too much vacuum on the inlet side of the pump?

Cavitation

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What is caused by extra air being drawn into the inlet side of the pump?

Psuedo-cavitation

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What are 2 reasons for psuedo-cavitation?

1) Crack on the inlet piping
2) Fluid level too low

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Substance used for transmitting energy from pump to actuator in a working hydraulic system?

Hydraulic fluid

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What 4 uses does hydraulic oil serve in a hydraulic system?

1) Transmits power
2) Lubricates parts
3) Cools moving parts
4) Seals clearances

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T or F:
Hydraulic oil is fire proof?

False

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When is hydraulic oil most dangerous?

When it’s atomized

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What are the 4 hydraulic additives?

1) Anti-wear
2) Wear resistant
3) Extreme pressure
4) Rust and oxidation inhibitor

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Coverts working energy into rotary mechanical energy?

Hydraulic motor

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Name 3 types of hydraulic motors?

1) Vane
2) Gear
3) Piston

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What are the 5 ways to identify a DCV?

1) Positions
2) Ways
3) Operated
4) Return or held
5) Center conditions

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How many positions can a DCV have?

2 or 3

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What is the minimum number of ways a DCV can have?

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What are the 4 ways a DCV can be operated?

1) Manual
2) Electrical
3) Pilot
4) Mechanical

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What are the 4 DCV centering conditions?

1) Float
2) Blocked
3) Open
4) Tandem

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Name 4 valve sizes by ports from smallest to largest?

1) D03
2) D05
3) D08
4) D010

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Allows flow in one direction only?

Check valve

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Name 3 applications a check valve can be used for?

1) By-pass check
2) Isolation/ back flow check
3) Pilot operated check

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Name the 3 types of accumulators:

1) Weight loaded
2) Spring loaded
3) Hydro-pnuematic

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Which accumulator type is charged with nitrogen?

Hydro-pnuematic

Name 3 uses of an accumulator:

1) Develop flow 2) Maintain pressure 3) Absorb shock

Name the 3 types of reservoirs:

1) Conventional 2) Overhead 3) L-shaped

What creates a quiet zone inside the reservoir?

Baffle plate

Name 3 purposes a baffle plate serve inside a reservoir:

1) Allows fluid to cool 2) Settle dirt 3) Allows trapped air to escape

Name 2 types of fluid coolers:

1) Air cooled 2) Water cooled

What are the 2 types of flow controls:

1) Fixed 2) Adjustable

What are 4 locations of hydraulic filters:

1) Sump strainer 2) Suction filter 3) Pressure filter 4) Return filter

What are the 4 hydraulic cylinder types:

1) Single acting 2) Double acting 3) Single rod 4) Double rod

What slows the rod speed at the end of its stroke?

Cushion valve

What helps eliminate shock in a hydraulic cylinder?

Cushion valve

Name 4 pressure control valves:

1) Relief valve 2) Sequence valve 3) Pressure reducing valve 4) Counterbalance valve

What 3 pressure control valves are normally non-passing?

1) Relief valve 2) Sequence valve 3) Counterbalance valve

Which pressure control valve normally has a built in bypass check?

Counterbalance valve

Which pressure control valve is normally passing?

Pressure reducing valve

What must be added in parallel with a sequence valve to allow reversible motion?

By-pass check

Name the 2 styles of positive displacement pumps:

1) Reciprocating 2) Rotary

T or F: Pumps create pressure?

False

What is pressure?

Force per unit area

Which pressure control valve limits system pressure?

Relief valve

Which pressure control valve allows one operation to happen before another operation?

Sequence valve

Which pressure control valve reduces downstream pressure after a valve?

Pressure reducing valve

Which pressure control valve counteracts a heavy weight on an actuator?

Counterbalance valve

What creates pressure?

Resistance to flow

What 3 things dictate the capacity of a pump?

1) Size of pump 2) Viscosity 3) RPM

Bearing for a split case pump is referred to as what?

In-between bearing

Bearing in an end suction pump is called what?

Overhung bearing

Rather than using a DCV, what is used to hold heavy loads in the air?

Pilot operated check valve

T or F: A safety relief valve is the only thing that limits system pressure when using a fixed displacement pump?

True

What are the 2 types of packing in a pump:

1) Mechanical 2) Compression packing

Which type of displacement controls pressure at the pump?

Variable

Name the 3 types of impellers used in pumps:

1) Open 2) Semi-open 3) Closed

List the 7 steps to setting the compensator on a pump:

1) Block flow 2) Back relief valve all the way out 3) Run compensator all the way in 4) Set relief valve pressure 5) Set system pressure 6) Lock jam nuts 7) Open flow

What is the separation of oil from water?

Phase separation

What is excessive flow over the case drain an indication of?

A failing pump

How is pressure measured?

PSI

How is flow in a hydraulic system measured?

GPM

Name 2 different types of hydraulic fluid:

1) Water based 2) Synthetic

Which pressure control valve has an external bleed line back to tank?

Sequence valve

Which 2 pressure control valves have the pilot before the valve:

1) Relief valve 2) Sequence valve

Which pressure control valve has an external pilot pressure that monitors the flow rate leaving the cylinder body?

Counterbalance valve

Is a 2 position DCV spring centered or spring returned?

Spring returned

Is a 3 position DCV spring centered or spring returned?

Spring centered

Which displacement pump has a case drain to help monitor pump life?

Variable displacement

Name 2 types of centrifugal pumps:

1) Split case 2) End suction

Which hydraulic filter is located inside the reservoir and can be hard to get to?

Sump strainer

Which hydraulic filter is located just before the pump inlet?

Suction filter

Which hydraulic filter is located after the pump but before the return?

Pressure filter

Which hydraulic filter is located just before the reservoir in the return system?

Return filter

What is the most common flow control?

Needle valve

Which of the 4 ways to operate a DCV has the ability to move the biggest spool type?

Pilot operated

Hydraulic Final #2 Flashcards

(75 cards)