Chapter 3 Hydraulic System Fundamentals

1. The temperature of a fluid will have no effect on its viscosity.

False

2. Maximum resistance occurs when there is no fluid flow in a hydraulic system.

True

3. Air is typically used in gas-charged accumulators.

False

4. Fluids follow the path of least resistance.

True

5. Friction generates energy that is converted into heat.

True

6. Using hydraulic system pressure valves, the inlet port is considered the secondary port and the outlet port is considered the primary port.

False

7. Most hydraulic fluid is oil-based.

True

8. The lower the precharge pressure, the less hydraulic fluid an accumulator can hold.

False

9. Custom-designed hydraulic power units can be sized for almost any power demand.

True

10. Hydraulic fluids with a high VI number change drastically as the temperature changes.

False

11. Hydraulic fluid is typically pure without any extra additives.

False

12. In a hydraulic system, the pressure in the system drops for a short period when several components activate at the same time.

True

13. A fluid with high viscosity is thin and flows easily.

False

14. To maintain a consistent flow rate, the velocity of a fluid can be increased or decreased as needed.

True

15. The viscosity of a specific fluid is always determined under conditions in the field.

False

16. Hydraulic power units are sometimes referred to as pumping units.

True

17. Liquids are easily compressed.

False

18. Fluids flow because they move from low-pressure areas to high-pressure areas.

False

19. In a hydraulic system, the bladder design is the most commonly used gas-charged accumulator.

True

20. There are 128 cu in. in one gallon.

False

21. Self-contained hydraulic power units are typically large and stationary.

False

22. Resistance to fluid flow in a hydraulic system is greatest at bends in the piping and when fluid flows through valves.

True

23. Cutaway diagrams are only drawn in single-line form.

False

24. Pictorial diagrams are not standardized.

True

25. The shorter the length of a hose, the more internal resistance it will have.

True

26. The color ___ in a color-coded cutaway diagram indicates intake flow from the reservoir through the filters to the pump.

A. green

B. orange

C. red

D. yellow

A. green

27. A ___ valve protects a fluid power system from overpressure by setting a maximum operating pressure.

A. directional control

B. flow control

C. pressure

D. relief

D. relief

28. The two types of mechanical accumulators include weight- and ___-loaded.

A. bladder

B. diaphragm

C. piston

D. spring

D. spring

29. In a hydraulic system, fluid flow is produced by a ___.

A. cylinder

B. motor

C. pressurized reservoir

D. pump

D. pump

30. ___ is the amount of fluid that passes a given point in one minute.

A. Flow rate

B. Fluid flow

C. Viscosity

D. Viscosity index

A. Flow rate

31. A(n) ___ is a vessel in which fluid is stored under pressure for future release of energy.

A. accumulator

B. cylinder

C. receiver

D. reservoir

A. accumulator

32. ___ is the ability to hold or contain something.

A. Area

B. Capacity

C. Cylinder size

D. Volume

B. Capacity

33. By controlling ___ and pressure, hydraulic systems can produce a large amount of work.

A. electrical energy

B. fluid flow

C. friction

D. mechanical energy

B. fluid flow

34. For industrial applications, hydraulic fluid viscosities are typically about ___ SUS at ___ °C.

A. 40; 100

B. 40; 150

C. 100; 40

D. 150; 40

D. 150; 40

35. Pressure ___ is the pressure difference between two points in a fluid power system.

A. accumulation

B. atmosphere

C. drop

D. relief

C. drop

36. ___ fluid flow is present in systems where pipes, tubes, and hoses may be too small for the system.

A. Laminar

B. Low-pressure

C. High-pressure

D. Turbulent

D. Turbulent

37. A ___ flow meter has high internal resistance to fluid flow.

A. digital

B. gas

C. liquid

D. weighted

D. weighted

38. ___ accumulators are typically small and lightweight, with capacities up to 1 gal.

A. Bladder gas-charged

B. Diaphragm gas-charged

C. Piston gas-charged

D. Spring-loaded

B. Diaphragm gas-charged

39. A(n) ___ diagram is a graphic representation of how devices interconnect within a fluid power system.

A. cutaway

B. engineering

C. pictorial

D. schematic

C. pictorial

40. On a schematic diagram, ___ lines are used represent pilot lines.

A. center

B. dashed

C. dotted

D. solid

B. dashed