Name: ________________________ Class: ___________________ Date: __________ ID: A

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MECH 1300 Final Review

True/FalseIndicate whether the statement is true or false.

____ 1. A larger Cv represents a smaller pressure drop at a given flow rate.

____ 2. Controlling the flow rate coming out of the rod end of a cylinder is called meter-in.

____ 3. Flow control valves control the flow rate of fluid in a circuit.

____ 4. Flow control valves are the only way to control the flow rate in a hydraulic circuit.

____ 5. A disadvantage of a flow control valve is that they cause increased inefficiency.

____ 6. Nonpositive displacement pumps typically operate by spinning the fluid with an impeller.

____ 7. Positive displacement pumps operate by opening up a cavity very quickly to create a vacuum.

____ 8. The three main types of construction for a positive displacement pumps are gear, vane, and piston.

Multiple ChoiceIdentify the choice that best completes the statement or answers the question.

____ 9. A system in which the motion is the mode of transmittal is know as a a. Hydrostatic System c. Thermodynamic Systemb. Hydrodynamic System d. Principle System

____ 10. A cylinder with a diameter of 300mm is loaded with a force of 50kN. What is the pressure (in kPa) inside the cylinder?a. 707 Pa c. 707 kPab. 176 kPa d. .70735 kPa

____ 11. Hydraulic fluid is flowing at a constant rate of 10 gpm through a conduit that has a 1.5in ID. What is the flow velocity in ft/s?a. 1.767 ft/s c. 1307 ft/sb. 2.634 ft/s d. 1.815 ft/s

Name: ________________________ ID: A

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CompletionComplete each statement.

12. Complete this circuit for a cylinder with meter-out control on the retract stroke. This circuit also rerquires a hydraulic motor and a pressure relief valve to be complete.

Short Answer

13. What are two of the most important advantages of fluid power transmission?

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14. What are the two areas that fluid power is divided into?

15. Fluid power applications fall into what three industrial segments?

16. What are the five basic components of a hydraulic system?

17. A cylinder with a diameter of 2.5 in is loaded with a force of 15,000 lb. What is the pressure inside the cylinder?

18. A cylinder with a diameter of 100mm is loaded with a force of 35kN. What is the pressure (in kPa) inside the cylinder?

19. An object weighs 2000 lbs. What is its mass?

20. Oil flows at a velocity of 10 ft/s through a conduit with an ID of 0.5 in. Determine the flow rate.

21. A cylinder with a bore diameter of 4 inches and a rod diameter of 2.25 in is to be used in a system with a maximum pressure of 3500 psi. What are the maximum extension and retraction forces?

22. A cylinder with a bore diameter of 200mm and a rod diameter of 60mm is to be used in a system with a maximum pressure of 20,000kPa. What are the maximum extension and retraction forces?

23. A cylinder is required to extend against a load of 25,000 lb with a maximum pressure of 2500psi. What is the minimum cylinder diameter required?

24. A cyinder with a bore diameter of 1.5 in and a rod diamter of 0.625 in is to be used in a system with a 8gpm pump. What are the extension and retraction speeds?

25. A cylinder with a bore diameter of 3.5 in is required to extend at a velocity of 2ft/s. What flow rate (in gpm) is required to achieve this speed?

26. A cylinder with a bore diameter of 63 mm is required to extend at a velocity of 0.5 m/s. What flow rate (in lpm) is required to achieve this speed?

27. Assuming a constant flow rate, will a double-acting, single rod cylinder travel faster on the extend stroke or on the retract stroke?

28. A cylinder with a bore diamter of 4 in and a rod diamter of 1.75 in is required to extend against a loacd of 20,000lb and to retract against a load of 1000lb. What pressure is required for each stroke?

29. What type of cylinder has a rod that extends from both ends, so that work and can be done on both ends?

30. What are the three types of control valves used in hydraulic systems?

31. What is the purpose of a check valve?

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32. Describe the difference between inline and subplate mounting of hydralic valves.

33. A cylinder with a bore diameter of 2 in and a rod diameter of 1 in is to be used in a system with a 10 gpm pump. What are the extension speeds when regenerating and when not regenerating?

34. A cylinder with a bore diameter of 2 in and a rod diameter of 1 in is to be used in a system with a 10 gpm pump. The system has a maximum pressure of 2500 psi. What are the maximum extension forces when regenerating and when not regenerating?

35. Know your Schematic Symbols:

36. What is the purpose of a pressure relief valve?

37. Describe the difference in operation between a direct-acting pressure relief valve and a pilot-operated pressure relief valve.

38. Define the terms cracking pressure, full-flow pressure, and pressure override with repect to pressure relief valves.

39. How is an unloading valve different from a pressure relief valve?

40. What is the purpose of a pressure reducing valve?

41. What is the purpose of a sequence valve?

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42. What is the purpose of a counterbalance valve?

43. What is the purpose of a break valve?

44. Use the graph below to determine the cracking pressure of the relief valve if the full-flow pressure is set to 2000 psi.

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45. Identify each pressure control valve symbol shown:

46. What is shifting shock?

47. Describe the operation of a solenoid.

48. What is the purpose of a proportional valve? How are they different from solenoid valves?

49. A cylinder is initially filled with 4ft3of air at a pressure of 20 psig. The air is compressed to a volume of

1ft3. What is the pressure in psig after compression.

50. A cylinder is initially filled with 5ft3of air at a pressure of 30 psig. The air is compressed to a volume of

2ft3. What is the pressure in psig after compression.

51. A cylinder is initially filled with 3m3of air at a pressure of 150 kPa gauge. The air is expanded to a volume

of 5m3. What is the pressure in kPa gauge after expansion?

52. Convert 68ºF to ºR

53. Convert 28ºC to K

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54. Air in a fixed volume container is initially at atmospheric pressure (0 psig) and 75ºF. Its temperature is then raised to 160ºF. What is the gauge pressure at the final temperature?

55. Air in a fixed volume container is initially at atmospheric pressure (0 kPa gauge) and 25ºC. Its temperature is then raised to 85ºC. What is the gauge pressure at the final temperature?

56. Air initially at 60ºF and 100 psig occupies a volume of 6ft3. If the air is heated to 310ºF while its volume is

reduced to 3ft3, what is the resulting final pressure?

57. Air initially at 15ºC and 800 kPa occupies a volume of 3m3. If the air is heated to 160ºC while its volume is

reduced to 0.3m3, what is the resulting final pressure?

58. Air initially at 68ºF and atmospheric pressure is compressed from 70ft3to12ft3. Assuming the process is adiabatic, what is the final pressue (in psig) of the gas?

59. A suction cup with an inside diameter of 1 in is used in a vacuum system that pulls 19 in Hg. What is the maximum lifting force?

Problem

60. For the following system:Input diameter = 1 in, output diameter = 2.5 in, input force = 250 lb. Calculate the output force and calculate how far we need to move the input cylinder to move the output cylinder 1 in.

61. A 15ft diameter cylindrical tank is filled with oil (γ = 0.0324lb / in 3) to a height of 30 ft. What is the pressure at the bottom of the tank?

62. A hydraulic system operates at 15 gpm and 3000 psi. How much hydraulic horsepower is being generated?

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63. What is the purpose of a pump?

64. What are the three main types of construction for positive displacement pumps?

65. Describe how nonpositive displacement pumps work.

66. Describe how positive displacement pumps work.

67. A pump has a displacement of 30cm3

rev and is driven at 1200 rpm. What is its theoretical flow rate?

68. A flow rate of 40 lpm is required for a system. If a 1200 rpm electric motor is use to drive the pump, what should the displacement be to achieve this rate?

69. A hydraulic pump with a displacement of 2 in 3

rev is selected for a system that will operate at a maximum

pressure of 2000 psi. What is the required torque?

70. An electric motor drives a pump at 1200 rpm with a torque of 400 in· lbs. What is the power input to this pump?

71. An electric motor drives a pump at 1600 rpm with a torque of 25N. What is the power input to this pump?

72. What kind of pump is this?

73. What kind of pump is this?

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74. What type of pump is this?

75. Define:AcuatorLinear ActuatorRotary ActuatorDouble Acting Cylinders

76. Name the types of single acting cylinders.

77. Define and know what they are used for:Tandem CylinderTelescopic CylinderHydraulic Ram PressDouble Rod Cylinder

78. Know these:

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79. Identify the number of ways, number of positions and the actuation method for each of the directional control valves shown:

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80. Match the neutral type to its description for each symbol:

81. know/define:Pilot to openPilot to closeBall ValveDetentShuttle valveDiverterTandem centerPressure relief valve

82. A valve with a CV of 2 gpm

psi has a pressure drop of 25 psi. What must the flow rate be throught the

valve? The system uses standard hydraulic oil. (S g = 0.9).

83. A valve with a CV of 2.3 lpm

kPa has a pressure drop of 150kPa. What must the flow rate be throught the

valve? The system uses standard hydraulic oil. (S g = 0.9).

Name: ________________________ ID: A

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84. A valve with a CV of 1.5 gpm

psi has a pressure drop of 20 psi. What must the flow rate be throught the

valve? The system uses standard hydraulic oil. (S g = 0.9).

85. A valve with a CV of 2 gpm

psi is being considered for use in a system that has a flow rate of 20gpm.

What will the pressure drop be across the valve? The system uses standard hydraulic oil. (S g = 0.9).

86. A valve with a CV of 2.5 lpm

kPa is being considered for use in a system that has a flow rate of 50lpm.

What will the pressure drop be across the valve? The system uses standard hydraulic oil. (S g = 0.9).

87. A valve with a CV of 1.5 gpm

psi is being considered for use in a system that has a flow rate of 30gpm.

What will the pressure drop be across the valve? The system uses standard hydraulic oil. (S g = 0.9).

88. Know/Define:Design SpeedFree SpeedSlideRunning TorqueStarting TorqueStall TorqueGrippersEscapements

89. Know these:

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90. Know These:

91. Know these DCV’s

92. An air-powered machine consumes 35 scfm at 90 psig. If the directional control valve that will control this machine can have a pressure drop of no more than 8 psi, what is the minimum CV ? Assume the temperature

of the air is 68ºF.

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93. Know/Define:Closed Loop SystemOpen Loop SystemSolenoid ValveProportional ValveElectroHydraulic Pump Control

94. Define:Boyles LawGay-Lussac’s LawCharles’s LawGeneral Gas LawVacuumIsothermal SystemAdiabatic System

Essay

95. Chapter 2 Review knowledge:

Define:Pascal’s LawBernoulli’s EquationFlow VelocityFlow RateBulk ModulusViscosityStatic Head PressureLaminar FlowTurbulent FlowLinear ActuatorRotary Actuator

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MECH 1300 Final ReviewAnswer Section

TRUE/FALSE

1. ANS: T PTS: 1 2. ANS: F PTS: 1 3. ANS: T PTS: 1 4. ANS: F

variable displacement can be used

PTS: 1 5. ANS: T PTS: 1 6. ANS: T PTS: 1 7. ANS: T PTS: 1 8. ANS: T PTS: 1

MULTIPLE CHOICE

9. ANS: B PTS: 1 10. ANS: C PTS: 1 11. ANS: D PTS: 1

COMPLETION

12. ANS:

PTS: 1

ID: A

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SHORT ANSWER

13. ANS: Multiply force and change direction quickly without damage to the system.

PTS: 1 14. ANS:

Hydraulics and Pneumatics

PTS: 1 15. ANS:

mobile hydraulic, industrial hydraulic and industrial pneumatic

PTS: 1 16. ANS:

Power Input Device, Control Devices, Power Output Device, Conductors, Liquid

PTS: 1 17. ANS:

3056 psi

PTS: 1 18. ANS:

4456 kPa

PTS: 1 19. ANS:

2000/32.2 = 62.11

PTS: 1 20. ANS:

6.11 gpm

Q = v * A

A = .1963

v = 10ft/s * 12in/1ft *60s/min =7200 in/min

Q = 7200 * .1963 = 1413.36

to gpm 1413.36 * 1/231 = 6.11 gpm

PTS: 1 21. ANS:

FE = 43980lb,FR = 30060lb

PTS: 1

ID: A

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22. ANS: FE = 628kN,FR = 571kN

PTS: 1 23. ANS:

3.57 in

PTS: 1 24. ANS:

1046 in/min (1.45 ft/s), 1265 in/min (1.76 ft/s)

PTS: 1 25. ANS:

60.0 gpm

PTS: 1 26. ANS:

93.5 lpm

PTS: 1 27. ANS:

The retract stroke

PTS: 1 28. ANS:

1592 psi, 98 psi

PTS: 1 29. ANS:

Double Rod Cylinder

PTS: 1 30. ANS:

Directional control valves. pressure control valves and flow control valves.

PTS: 1 31. ANS:

To allow flow in one direction and to block flow in the other direction.

PTS: 1 32. ANS:

Inline mounted have ports threaded directly into the valve, while subplate mounted valves have unthreaded connections on the bottom of the valve. The valve is then attached to a sub-plate that has matching connections. The sub-plate has the threaded connections to which the fittings are attached.

PTS: 1

ID: A

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33. ANS: 2941 in/min

PTS: 1 34. ANS:

1964 lb, 7855 lb

PTS: 1 35. ANS:

see text/notes

PTS: 1 36. ANS:

A pressure relief valve limits the maximum pressure in a hydraulic circuit.

PTS: 1 37. ANS:

A direct-acting pressure relief valve has a single stage in which a poppet or ball is subjected to pressure on one side and pressure on the other. A pilot operated pressure relief valve has a two-stage arrangement in which a pilot poppet opens,which causes a pressure drop across a main piston, causing it to open and allow full flow back to the tank.

PTS: 1 38. ANS:

Cracking pressure - the pressure at which the pressure relief valve just begins to open. Full-flow pressure - the pressure at which the pressure relief valve is fully open and sending all the pump flow back to the tank. Pressure override - the difference between the full flow and cracking pressures.

PTS: 1 39. ANS:

An unloading valve reads the pressure in an external line, while a pressure relief valve reads the pressure in its own line.

PTS: 1 40. ANS:

To maintain a reduced pressure in a branch circuit.

PTS: 1 41. ANS:

To force to actuators to actuate in sequence.

PTS: 1 42. ANS:

To counterbalance a weight being held by a hydraulic cylinder

PTS: 1

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43. ANS: To prevent an overrruning load from driving the hydraulic motor.

PTS: 1 44. ANS:

Approximately 1650 psi

PTS: 1 45. ANS:

1) Pressure relief valve2) Pressure unloading valve3) Pressure reducing valve

PTS: 1 46. ANS:

Occurs when directional control valves are shifted into the closed position. Shifting the valve closed can cause a pressure spike on the outlet line.

PTS: 1 47. ANS:

A solenoid operates on the principle that when a current is applied to a coil of wires a magnetic field is generated within the coil. The magnetic field is used to move a plunger, which can be used to shift a valve spool.

PTS: 1 48. ANS:

Proportional valves allow the valve spool to be precisely positioned between the open and closed positions, which allows the valve to control flow rate and pressure in additioin to direction. Solenoid valves only control direction because they only have two states: open or closed.

PTS: 1 49. ANS:

124.1psig

p1 = 20psig + 14.7psia = 34.7psia

p2 =p 1V1

V2

= 34.7 * 41

= 138.8psia

p2 = 138.8psia − 14.7psia = 124.1psig

PTS: 1

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50. ANS: 97.05 psig

p1 = 30psig + 14.7psia = 44.7psia

p2 =p 1V1

V2

= 44.7 * 52

= 111.75psia

p2 = 111.75psia − 14.7psia = 97.05psig

PTS: 1 51. ANS:

49.6kPa gauge

p1 = 150kPagauge + 101kPa abs= 251kPa abs

p2 =p1V1

V2

= 251 * 35

= 150.6kPa abs

p2 = 150.6kPa abs− 101kpa abs= 49.6kPagauge

PTS: 1 52. ANS:

528

68+460=528

PTS: 1 53. ANS:

301K

28+273 = 301

PTS: 1 54. ANS:

2.3psig

T1 = 75+ 460= 535

T2 = 160+ 460= 620

p1 = 0psig + 14.7psia = 14.7psia

p2 = 14.7 *620535

= 17.03psia

17.03− 14.7= 2.3psig

PTS: 1

ID: A

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55. ANS: 20.33 kPa gauge

T1 = 25+ 273= 298K

T2 = 85+ 273= 358K

p1 = 0kPagauge + 101kPa abs= 101kPa abs

p2 = 101 *358298

= 121.33kPa abs

121.33− 101= 20.33kPagauge

PTS: 1 56. ANS:

324.98 psigGeneral gas lawT1 = 520

T2 = 770

pabs = 100+ 14.7= 114.7psia

p2 = 770 * 114.7 * 6520 * 3

= 339.68psia

p2 = 339.68− 14.7= 324.98psig

PTS: 1 57. ANS:

13445 kPa gaugeGeneral gas lawT1 = 288

T2 = 433

pabs = 800+ 101= 901kPa abs

p2 = 433 * 901 * 3288 * 0.3

= 13546kPa abs

p2 = 13546kPa abs− 101= 13445kPagauge

PTS: 1 58. ANS:

158.92 psig

PTS: 1

ID: A

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59. ANS: 7.32 lbs

Convert to psig

19inHg *−0.491psig

1inHG= −9.32psig

A = 3.142 * 12

4= 0.785

F = p * A = −9.32 * 0.785= −7.32

Negative signifies that the object is being drawn toward the suction cup

PTS: 1

PROBLEM

60. ANS: 1563 lbs, 6.25 in

PTS: 1 61. ANS:

11.7 psi

Static Head PressurepH = γ ⋅ h

h = 30 * 12 = 360 in

=0.0324 * 360 = 11.7 psi

PTS: 1 62. ANS:

26.3 hp

(3000 * 15) / 1714 = 26.3

PTS: 1 63. ANS:

To create flow

PTS: 1 64. ANS:

gear, vane and piston

PTS: 1

ID: A

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65. ANS: Nonpositive displacement pumps typically operate by spinning the fluid with an impeller.

PTS: 1 66. ANS:

Positive displacement pumps operate by opening up a cavity very quickly to create a vacuum.

PTS: 1 67. ANS:

36 l/min

PTS: 1 68. ANS:

33.3 in3

rev

PTS: 1 69. ANS:

637 in lbs

PTS: 1 70. ANS:

8 hp

PTS: 1 71. ANS:

4.18kW

PTS: 1 72. ANS:

Gear pump

PTS: 1 73. ANS:

Vane pump

PTS: 1 74. ANS:

Piston pump

PTS: 1 75. ANS:

see notes/text

PTS: 1

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76. ANS: Push, pull, single return

PTS: 1 77. ANS:

see notes/text

PTS: 1 78. ANS:

See notes/text

PTS: 1 79. ANS:

Four-way, three position, solenoid actuatedtwo-way, two-position, manual lever actuatedthree-way, two position, pilot actuated

PTS: 1 80. ANS:

B, D, A, C

PTS: 1 81. ANS:

see notes/text

PTS: 1 82. ANS:

Q = CV *P

S g

=10.54gpm

PTS: 1 83. ANS:

Q = CV *P

S g

=29.69lpm

PTS: 1 84. ANS:

Q = CV *P

S g

=7.07gpm

PTS: 1

ID: A

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85. ANS:

p =Q2

CVÊËÁÁ ˆ

¯˜̃

2 * S g = 90psi

PTS: 1 86. ANS:

p =Q2

CVÊËÁÁ ˆ

¯˜̃

2 * S g = 360kPa

PTS: 1 87. ANS:

p =Q2

CVÊËÁÁ ˆ

¯˜̃

2 * S g = 360psi

PTS: 1 88. ANS:

see text chapter 12 and notes

PTS: 1 89. ANS:

See Chapter 12 and notes

PTS: 1

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90. ANS:

PTS: 1 91. ANS:

See page 439 in text

PTS: 1 92. ANS:

1.236AbsolutesPOUT = 90+ 14.7= 104.7psia

T = 68+ 460= 528oR

CV =Q

22.48T

∆p * p OUT

= 3522.48

5288 * 104.7

=1.236

PTS: 1

ID: A

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93. ANS: See Chapter 13 in text/notes

PTS: 1 94. ANS:

See Text

PTS: 1

ESSAY

95. ANS: Read Chapter 2

PTS: 1