Hydraulic Acc. B/Maint.

Question 1

Static seals vs. Dynamic Seals

Answer 1

• static seals do not move with respect to eachother

- dynamic seals must seal against a moving surface

Question 2

O-ring Gaskets

Answer 2

• 10% protrusion

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

Question 3

Rod Seals

Answer 3

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

Question 4

Accumulators

Answer 4

• 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

Question 5

Positive seal vs. non-positive seals

Answer 5

• positive seals do not allow any leakage

- non positive allow controlled leakage for lubrication, vanes

Question 6

Accumulator pre-charging

Answer 6

• 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

Question 7

Test instruments needed

Answer 7

• flow meter
• pressure gauge
• thermometer
• tachometer

Question 8

What protects pressure gauges from force and oscillating

Answer 8

-scrubber

Question 9

Tubing efficiency

Answer 9

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