Hydraulic Acc. B/Maint. Flashcards Preview

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Flashcards in Hydraulic Acc. B/Maint. Deck (9)
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1
Q

Static seals vs. Dynamic Seals

A
  • static seals do not move with respect to eachother

- dynamic seals must seal against a moving surface

2
Q

O-ring Gaskets

A
  • 10% protrusion

- can expand and compress to maintain a seal like in extrusion

3
Q

Rod Seals

A

-o-ring (static) seal on the outside, dynamic seal on the inside against the rod

4
Q

Accumulators

A
  • to add pressurized fluid to the system whenever needed.
  • absorbs shock load, even out pulsations, protects against over pressure due to thermal expansion.
  • to provide extra flow
5
Q

Positive seal vs. non-positive seals

A
  • positive seals do not allow any leakage

- non positive allow controlled leakage for lubrication, vanes

6
Q

Accumulator pre-charging

A
  • energy storage pre charge to 90% of minimum system pressure
  • for pulsation its 70% of normal system pressure
  • shock absorption its 75% of normal system pressure
  • pre charge is done when tank is empty and should never be less than 25% of max system pressure
7
Q

Test instruments needed

A
  • flow meter
  • pressure gauge
  • thermometer
  • tachometer
8
Q

What protects pressure gauges from force and oscillating

A

-scrubber

9
Q

Tubing efficiency

A

-when tubing diameter decreases fluid velocity increases. Tubing effects efficiency