Chapter 1.2: Properties and Types of Hydraulic Fluids

Question 1

purpose of hydraulic fluid

Answer 1

1) transmit power
2) lubricate moving parts
3) cool & dissipate heat

Question 2

properties of hydraulic fluid

Answer 2

1) viscosity (high VI)
2) chemical stability
3) flash point
4) fire point

Question 3

types of hydraulic fluids

Answer 3

1) Mineral based fluid
2) Polyalphaolefin based fluid
3) Phosphate ester based fluid

Question 4

mineral based fluid points

Answer 4

1) processed from petroleum
2) used in systems where fire hazard is low

Question 5

polyalphaolefin based fluid points

Answer 5

1) better fire resistance than mineral based
2) when in low temp, the viscosity of fluid increases

Question 6

phosphate ester based fluid points

Answer 6

1) most commonly used in commercial a/c
2) extremely fire-resistant

Question 7

define viscosity index (VI)

Answer 7

relationship between viscosity and temperature of oil

high VI - less change in viscosity with change in temp.

Question 8

flash point vs fire point

Answer 8

flash point: temperature that would ignite momentarily when exposed to flame

fire point: temperature that would ignite continuously when exposed to spark or flame

Question 9

safety precautions working with hydraulic fluids

Answer 9

wear gloves, eye protection, respirator