Introduction to fluid power
1. What is fluid power?
The use of fluids to transmit power
2. What is viscosity index?
A measure of a fluid's resistance to flow
3. Who is credited with discovering Pascal's law?
Blaise Pascal
4. What is the basic component of fluid power?
Actuators
5. What are the advantages of fluid power?
a) High power-to-weight ratio
b) Easy control of motion
6. What are some common applications of fluid power?
a) Hydraulic brakes in cars
b) Aircraft landing gear
7. What is a hydraulic cylinder?
A device that converts fluid power into linear motion
8. What is a pneumatic system?
A system that uses compressed air to transmit power
9. What is the function of a hydraulic pump?
To convert mechanical power into hydraulic power
10. What is the purpose of a hydraulic accumulator?
a) To store hydraulic fluid for future use
b) To absorb pressure fluctuations in a system
11. What is the classification of hydraulic pumps?
Both A and B (positive displacement and non-positive displacement, fixed displacement
and variable displacement)
12. What is the pumping theory?
The study of how fluids are moved by pumps
13. What is a gear pump?
A type of hydraulic pump that uses gears to pump fluid
14. What is a vane pump?
A type of hydraulic pump that uses vanes to pump fluid
15. What is a piston pump?
A type of hydraulic pump that uses pistons to pump fluid
16. What is volumetric displacement?
The amount of fluid pumped per unit of time
17. What are pump performances?
The characteristics of a pump, including its flow rate, pressure, and efficiency
18. What is pump noise?
The sound made by a pump while in operation
19. What is pump cavitation?
The formation of air bubbles in a pump due to low pressure
20. Explain the advantage of fluid power over other types of power transmission.
Fluid power offers several advantages over other types of power transmission, such as
electrical or mechanical. Some of these advantages include high power density, easy
control of force and speed, ability to transmit power over long distances, and resistance to
shock and vibration.
21. What are some common applications of fluid power?
Common applications of fluid power include heavy machinery, construction equipment,
aerospace systems, marine vessels, and industrial automation systems.
22. Define viscosity index and its importance in hydraulic systems.
Viscosity index is a measure of how a fluid's viscosity changes with temperature. In
hydraulic systems, it is important to select fluids with appropriate viscosity index to ensure
smooth operation and efficient performance.
23. Explain Pascal's law and its application in hydraulic systems.
Pascal's law states that when pressure is applied to a fluid in a closed system, the pressure
is transmitted equally in all directions. In hydraulic systems, this law is used to transmit
force from one point to another using a fluid medium.
24. List some basic components of a fluid power system and their functions.
Basic components of a fluid power system include a pump, reservoir, valves, actuators, and
a fluid medium. The pump generates fluid flow, the reservoir stores the fluid, valves control
the flow and pressure, actuators convert fluid pressure into mechanical force or motion,
and the fluid medium transmits power.
25. Describe the operation of a gear pump and a vane pump.
A gear pump works by using meshing gears to pump fluid, while a vane pump uses sliding
vanes to create flow. In a gear pump, the fluid enters the inlet port and is trapped between
the teeth of the rotating gears, which then carries the fluid around to the outlet port. In a
vane pump, fluid is drawn into the pump and is trapped between the vanes and the pump
housing, which then pushes the fluid around to the outlet port.
26. What is meant by pump cavitation and how can it be prevented?
Pump cavitation occurs when air bubbles form in the fluid due to low pressure, which can
cause damage to the pump and reduce its efficiency. It can be prevented by maintaining
proper fluid levels, avoiding high suction pressures, and ensuring that the pump is properly
sized for the system.
27. What factors should be considered when selecting a hydraulic pump?
Factors to consider when selecting a hydraulic pump include flow rate, pressure range, fluid
viscosity, temperature range, and pump efficiency. Other factors may include the size and
weight of the pump, compatibility with other system components, and cost.
28. Explain the significance of pump performances in hydraulic systems.
Pump performances such as flow rate, pressure, and efficiency are important in hydraulic
systems because they affect the overall system performance and energy efficiency.
Properly selecting and maintaining a pump can help ensure reliable and efficient operation.
29. What are some common causes of pump noise and how can it be reduced?
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Common causes of pump noise include cavitation, high fluid velocity, loose mounting, and
worn bearings. It can be reduced by addressing the root cause of the noise, such as
reducing fluid velocity, tightening mounts, or replacing worn components.
Hydraulic cylinders
What is the force exerted by a hydraulic cylinder with a piston diameter of 4 inches and a
pressure of 2000 psi?
8000 lb (Force = Pressure x Area, Area = π x (diameter/2)^2 = 3.14 x (4/2)^2 = 12.56 sq in,
Force = 2000 psi x 12.56 sq in = 8000 lb)A hydraulic cylinder has a bore diameter of 3 inches
and a stroke length of 12 inches.
What is the volume of fluid required to extend the cylinder?
113.1 cubic inches (Volume = Area x Stroke length, Area = π x (diameter/2)^2 = 3.14 x
(3/2)^2 = 7.07 sq in, Volume = 7.07 sq in x 12 inches = 84.84 cubic inches)
A hydraulic cylinder has a maximum force of 10,000 lb and a velocity of 2 inches per
second. What is the power output of the cylinder?
10,000 watts (Power = Force x Velocity, Power = 10,000 lb x 2 inches/second = 20,000 inchlb/second or 10,000 watts)
A hydraulic cylinder with a 2-inch bore diameter and a 10-inch stroke length has a force of
3000 lb. What is the pressure in the cylinder?
300 psi (Force = Pressure x Area, Area = π x (diameter/2)^2 = 3.14 x (2/2)^2 = 3.14 sq in,
Pressure = 3000 lb / 3.14 sq in = 955.4 psi)
A hydraulic cylinder with a bore diameter of 6 inches and a pressure of 1500 psi has a force
of 28,274 lb. What is the velocity of the cylinder?
0.5 inches per second (Force = Pressure x Area, Area = π x (diameter/2)^2 = 3.14 x (6/2)^2 =
28.27 sq in, Velocity = Force / (Area x Pressure), Velocity = 28,274 lb / (28.27 sq in x 1500
psi) = 0.5 inches per second)
A hydraulic cylinder with a bore diameter of 5 inches is mounted on a flange. What is the
mounting surface area of the flange?
15.71 sq in (Area = π x (diameter/2)^2 = 3.14 x (5/2)^2 = 19.63 sq in, Subtracting the
cylinder rod area gives the mounting surface area, Mounting surface area = 19.63 sq in (3.14 x (1/2)^2) = 15.71 sq in
What is the function of a hydraulic cylinder?
To convert fluid power into linear motion
What are the two types of hydraulic cylinder operating features?
Double-acting and single-acting
What are the two types of cylinder mounting?
Flange and base
What is the equation for cylinder force?
Force = pressure x area
What is cylinder velocity?
The speed at which the cylinder extends and retracts
What is cylinder power?
The rate at which the cylinder can perform work
What are special cylinder designs?
Telescoping cylinders and tandem cylinders
How can cylinder loading be achieved through mechanical linkages?
Using a lever arm or a pulley system
What are hydraulic cylinder cushions?
Devices that reduce the impact of the cylinder at the end of the stroke
45. What is the purpose of hydraulic cylinder cushions?
To prevent damage to the cylinder and other components
Hydraulic motor
46. What is a hydraulic motor?
A hydraulic motor is a device that converts hydraulic energy into mechanical energy in the
form of rotational motion.
47. What is limited rotation in hydraulic motors?
Limited rotation is a type of hydraulic motor that has a limited range of rotation, typically less
than 360 degrees.
48. What are the three types of hydraulic motors?
The three types of hydraulic motors are geramotors, vane motors, and piston motors.
49. What is a geramotor?
A geramotor is a type of hydraulic motor that uses a rotor with teeth to transfer fluid
pressure into rotational motion.
50. What is a vane motor?
A vane motor is a type of hydraulic motor that uses vanes mounted on a rotor to transfer
fluid pressure into rotational motion.
51. What is a piston motor?
A piston motor is a type of hydraulic motor that uses pistons to transfer fluid pressure into
rotational motion.
52. What is theoretical torque?
Theoretical torque is the maximum amount of torque a hydraulic motor can produce based
on its design and operating parameters.
53. What is power in hydraulic motors?
Power in hydraulic motors is the rate at which work is performed, typically measured in
horsepower or watts.
54. What is flow rate in hydraulic motors?
Flow rate in hydraulic motors is the volume of fluid that is moved through the motor per unit
of time.
55. What is hydraulic motor performance?
Hydraulic motor performance refers to the efficiency, power output, and reliability of a
hydraulic motor.
56. What is a hydrostatic transmission?
A hydrostatic transmission is a type of transmission that uses hydraulic fluid to transmit
power from the engine to the wheels or other driven components.
57. A hydraulic motor has a displacement of 20 cubic inches and operates at a pressure of 2000
psi. What is the theoretical torque of the motor? Answer: Theoretical torque = (Pressure x
Displacement) / (2 x pi) = (2000 x 20) / (2 x 3.14) = 635.76 lb-in
58. A vane motor has a displacement of 10 cubic inches and operates at a flow rate of 5 gallons
per minute. What is the motor's rotational speed? Answer: Rotational speed = (Flow rate x
231) / Displacement = (5 x 231) / 10 = 115.5 rpm
59. A hydraulic motor has a power output of 15 horsepower and operates at a pressure of 3000
psi. What is the flow rate of the motor? Answer: Power = (Pressure x Flow rate) / 1714, so
Flow rate = (Power x 1714) / Pressure = (15 x 1714) / 3000 = 8.57 gallons per minute
60. A geramotor has a theoretical torque of 800 lb-in and operates at a rotational speed of 500
rpm. What is the power output of the motor? Answer: Power = (Theoretical torque x
Rotational speed) / 63,025 = (800 x 500) / 63,025 = 6.35 horsepower
61. A hydraulic motor has a flow rate of 20 gallons per minute and operates at a pressure of
2000 psi. What is the power output of the motor? Answer: Power = (Pressure x Flow rate) /
1714 = (2000 x 20) / 1714 = 23.28 horsepower
62. A piston motor has a displacement of 25 cubic inches and operates at a pressure of 2500 psi.
What is the theoretical torque of the motor? Answer: Theoretical torque = (Pressure x
Displacement) / (2 x pi) = (2500 x 25) / (2 x 3.14) = 997.46 lb-in
63. A vane motor has a power output of 10 horsepower and operates at a rotational speed of
1000 rpm. What is the theoretical torque of the motor? Answer: Theoretical torque = (Power
x 63,025) / Rotational speed = (10 x 63,025) / 1000 = 630.25 lb-in
64. A hydraulic motor has a flow rate of 15 gallons per minute and operates at a pressure of
3000 psi. What is the power output of the motor? Answer: Power = (Pressure x Flow rate) /
1714 = (3000 x 15) / 1714 = 26.20 horsepower
65. A geramotor has a power output of 8 horsepower and operates at a rotational speed of 750
rpm. What is the theoretical torque of the motor? Answer: Theoretical torque = (Power x
63,025) / Rotational speed = (8 x 63,025) / 750 = 670.17 lb-in
66. A hydraulic motor has a power output of 12 horsepower and operates at a pressure of 2000
psi. What is the flow rate of the motor? Answer: Power = (Pressure x Flow rate) / 1714, so
Flow rate = (Power x 1714) / Pressure = (12 x 1714) / 2000 = 10.28 gallons per minute
67. A hydraulic motor has a displacement of 20 cubic inches and operates at a pressure of 2000
psi. What is the theoretical torque of the motor? Answer: Theoretical torque = (Pressure x
Displacement) / (2 x pi) = (2000 x 20) / (2 x 3.14) = 635.76 lb-in
68. A vane motor has a displacement of 10 cubic inches and operates at a flow rate of 5 gallons
per minute. What is the motor's rotational speed? Answer: Rotational speed = (Flow rate x
231) / Displacement = (5 x 231) / 10 = 115.5 rpm
69. A hydraulic motor has a power output of 15 horsepower and operates at a pressure of 3000
psi. What is the flow rate of the motor? Answer: Power = (Pressure x Flow rate) / 1714, so
Flow rate = (Power x 1714) / Pressure = (15 x 1714) / 3000 = 8.57 gallons per minute
70. A geramotor has a theoretical torque of 800 lb-in and operates at a rotational speed of 500
rpm. What is the power output of the motor?
Power = (Theoretical torque x Rotational speed) / 63,025 = (800 x 500) / 63,025 = 6.35
horsepower
71. A hydraulic motor has a flow rate of 20 gallons per minute and operates at a pressure of
2000 psi. What is the power output of the motor?
Power = (Pressure x Flow rate) / 1714 = (2000 x 20) / 1714 = 23.28 horsepower
72. A piston motor has a displacement of 25 cubic inches and operates at a pressure of 2500
psi. What is the theoretical torque of the motor?
Theoretical torque = (Pressure x Displacement) / (2 x pi) = (2500 x 25) / (2 x 3.14) = 997.46
lb-in
73. A vane motor has a power output of 10 horsepower and operates at a rotational speed of
1000 rpm. What is the theoretical torque of the motor?
Theoretical torque = (Power x 63,025) / Rotational speed = (10 x 63,025) / 1000 = 630.25 lbin
74. A hydraulic motor has a flow rate of 15 gallons per minute and operates at a pressure of
3000 psi. What is the power output of the motor?
Power = (Pressure x Flow rate) / 1714 = (3000 x 15) / 1714 = 26.20 horsepower
75. A geramotor has a power output of 8 horsepower and operates at a rotational speed of 750
rpm. What is the theoretical torque of the motor?
Theoretical torque = (Power x 63,025) / Rotational speed = (8 x 63,025) / 750 = 670.17 lb-in
76. A hydraulic motor has a power output of 12 horsepower and operates at a pressure of 2000
psi. What is the flow rate of the motor?
Power = (Pressure x Flow rate) / 1714, so Flow rate = (Power x 1714) / Pressure = (12 x
1714) / 2000 = 10.28 gallons per minute
Hydraulic valves
77. Which type of valve is used to control the direction of hydraulic fluid flow?
Directional control valve
78. What type of valve is used to prevent backflow in a hydraulic system?
Check valve
79. Which type of check valve requires a pilot pressure to open?
Pilot operated check valve
80. What type of valve is used to divert hydraulic fluid flow between two different circuits?
Three way valve
81. What type of valve is used to control the flow of hydraulic fluid between two actuator
ports and a common return port?
Four way valve
82. What type of valve is operated manually by a lever or knob?
Manually actuated valve
83. What type of valve is operated by a pilot pressure signal from another valve?
Pilot actuated valve
84. What type of valve is operated by an electrical signal from a solenoid?
Solenoid actuated valve
85. What type of valve is used to control the pressure in a hydraulic system?
Pressure control valve
86. What type of valve is used to protect a hydraulic system from overpressure?
Pressure relief valve
87. What type of pressure relief valve can handle both high and low pressures?
Compound pressure relief valve
88. What type of valve is used to maintain a constant pressure downstream of the valve?
Pressure reducing valve
89. What type of valve is used to unload a pump when the system pressure reaches a certain
level?
Unloading valve
90. What type of valve is used to ensure that one actuator operates before another in a
hydraulic system?
Sequence valve
91. What type of valve is used to control the flow rate of hydraulic fluid in a system?
Flow control valve
92. What type of valve is used to regulate the flow of hydraulic fluid regardless of the
pressure?
On-pressure compensated valve
93. What type of valve is used to maintain a constant flow rate regardless of the pressure?
Pressure compensated valve
94. What type of valve is used to accurately control the position of a hydraulic actuator?
Servo valve
95. What type of valve is used to control the speed of a hydraulic actuator?
Flow control valve
96. What type of valve is used to accurately control the flow rate of hydraulic fluid through a
small orifice?
Needle valve
97. What type of valve is used to accurately control the position of a hydraulic actuator using
electrical signals?
Electrohydraulic servovalves
98. What type of valve is used to control the flow rate of hydraulic fluid in proportion to an
electrical input signal?
Proportional control valves
99. What type of valve is designed to be installed in a manifold block or valve body? Cartridge
valve
100. What type of valve is used to protect a hydraulic system from catastrophic failure due
to overpressure?
Hydraulic fuse
101. What is a hydraulic circuit?
A hydraulic circuit is a system that uses hydraulic fluid to transmit power from one
component to another, typically consisting of a pump, hydraulic fluid, valves, and
actuators.
102. What is a single acting hydraulic cylinder circuit?
A single acting hydraulic cylinder circuit is a hydraulic system that uses a single acting
hydraulic cylinder to perform work in one direction, relying on an external force to return
the cylinder to its original position.
103. What is a double acting hydraulic cylinder circuit?
A double acting hydraulic cylinder circuit is a hydraulic system that uses a double acting
hydraulic cylinder to perform work in both directions, with the hydraulic fluid being used
to extend and retract the cylinder.
104. What is a regenerative cylinder circuit?
A regenerative cylinder circuit is a hydraulic system that uses the hydraulic fluid from one
side of a double acting cylinder to extend the other side, providing a faster cycle time and
increased productivity.
105. What is a drilling machine application in hydraulic systems?
A drilling machine application in hydraulic systems is the use of hydraulic power to drive
the drilling mechanism, controlling the feed and speed of the drill bit.
106. What is a pump unloading circuit?
A pump unloading circuit is a hydraulic system that allows the pump to continue running
without producing pressure, diverting the hydraulic fluid back to the reservoir when the
pressure reaches a certain level.
107. What is a double pump hydraulic system?
A double pump hydraulic system is a hydraulic system that uses two pumps to provide
hydraulic power to the system, increasing the flow rate and capacity of the system.
108. What is a counter valve application in hydraulic systems?
A counter valve application in hydraulic systems is the use of a counter balance valve to
control the movement of a hydraulic cylinder, preventing it from moving under the weight
of a load.
109. What are hydraulic cylinder sequencing circuits?
Hydraulic cylinder sequencing circuits are hydraulic systems that use multiple hydraulic
cylinders to perform a task in a specific sequence, with each cylinder being activated in
turn to complete the task.
110. What is an automatic cylinder reciprocating system?
An automatic cylinder reciprocating system is a hydraulic system that uses a control
system to automatically cycle a hydraulic cylinder back and forth, with the cycle time and
stroke length being adjustable.
111. What is a locked cylinder using pilot check valves?
A locked cylinder using pilot check valves is a hydraulic system that locks a hydraulic
cylinder in place using a pilot operated check valve, preventing it from moving due to
external forces.
112. What are cylinder synchronizing circuits?
Cylinder synchronizing circuits are hydraulic systems that use multiple hydraulic cylinders
to perform a task in a synchronized manner, with the cylinders being linked together to
move in unison.
113. What is a fail safe circuit in hydraulic systems?
A fail safe circuit in hydraulic systems is a safety mechanism that ensures that the system
will fail in a safe manner if there is a malfunction or failure in the system.
114. What is speed control of a hydraulic cylinder?
Speed control of a hydraulic cylinder is the ability to adjust the speed at which a hydraulic
cylinder extends and retracts, typically using flow control valves or proportional control
valves.
115. What is speed control of a hydraulic motor?
Speed control of a hydraulic motor is the ability to adjust the speed at which a hydraulic
motor rotates, typically using a flow control valve or a proportional control valve.
116. What are accumulators in hydraulic systems?
Accumulators are hydraulic components that store pressurized hydraulic fluid, providing a
source of energy that can be used to power hydraulic actuators or absorb shocks and
vibrations in the system.
117.
A pump has a displacement volume of 98.4 cm3. It delivers 0.0152 m3/s of oil at
1000 RPM and 70 bar. If the prime move in put torque is 124.3 Nm. What is the
overall efficiency of pump? What is the theoretical torque required to operate the
pump?
To calculate the overall efficiency of the pump, we can use the following formula:
Overall efficiency = (output power / input power) x 100%
First, let's calculate the output power of the pump:
Output power = flow rate x pressure x specific gravity x pump efficiency
The specific gravity of oil is typically around 0.9, and assuming a pump efficiency of 80%, we
have:
Output power = 0.0152 m^3/s x 70 bar x 0.9 x 0.8 = 0.074 kW
Next, let's calculate the input power of the pump:
Input power = torque x angular velocity
The angular velocity at 1000 RPM is:
Angular velocity = 1000 RPM x 2π / 60 = 104.72 rad/s
Therefore, the input power is:
Input power = 124.3 Nm x 104.72 rad/s = 13.01 kW
Now we can calculate the overall efficiency:
Overall efficiency = (output power / input power) x 100% = (0.074 kW / 13.01 kW) x 100% =
0.57%
To calculate the theoretical torque required to operate the pump, we can use the following
formula:
Torque = pressure x displacement volume / (2π)
Substituting the given values, we have:
Torque = 70 bar x 98.4 cm^3 / (2π x 100 cm/m) = 111.9 Nm
Therefore, the theoretical torque required to operate the pump is 111.9 Nm.
118.
How much hydraulic power would a pump produce when operating at 140 bar
and delivering 0.001m3/s of oil? What power rated electric-motor would be selected
to drive this pump if its overall efficiency is 85%?
The hydraulic power produced by the pump can be calculated as follows:
Hydraulic power = pressure x flow rate
Substituting the given values, we have:
Hydraulic power = 140 bar x 0.001 m^3/s = 0.14 kW
Now, to calculate the power rating of the electric motor required to drive the pump, we can
use the following formula:
Input power = output power / efficiency
Substituting the given values, we have:
Input power = 0.14 kW / 0.85 = 0.165 kW
Therefore, the power rated electric motor required to drive the pump would be at least
0.165 kW or 165 watts.
119.
A pump having a volumetric efficiency of 96% delivers 29 LPM of oil at 1000
RPM. What is the volumetric displacement of the pump?
Given, Volumetric efficiency (ηv) = 96%
Flow rate (Q) = 29 LPM
Pump Speed (N) = 1000 RPM
Volumetric displacement of the pump can be calculated using the following formula:
Volumetric displacement = (Q × 100) / (N × ηv)
= (29 × 100) / (1000 × 0.96)
= 3.02 L/rev
Therefore, the volumetric displacement of the pump is 3.02 L/rev.
120.
A gear pump has an outside diameter of 82.6mm, inside diameter of 57.2 mm
and a width of 25.4mm. If the actual pump flowis 1800 RPM and the rated pressure is
0.00183 what is the volumetric efficiency? What is the theoretical flowrate from a
fixed-displacement axial piston pump with an inebore cylinder operating at 2000RPM?
Each bore has a diameter of 15 mm and stroke is 20mm.
Outside diameter of gear pump (D) = 82.6mm
Inside diameter of gear pump (d) = 57.2mm
Width of gear pump (W) = 25.4mm
Actual pump flow (Q) = 1800 RPM
Rated pressure (P) = 0.00183
Theoretical displacement of the pump can be calculated using the following formula:
Theoretical displacement = (π/4) × (D² - d²) × W
= (π/4) × (82.6² - 57.2²) × 25.4
= 305,798.14 mm³/rev
Actual displacement of the pump can be calculated using the following formula:
Actual displacement = Q × Theoretical displacement
= 1800 × 305,798.14
= 550,436,652 mm³/min
Actual flow rate of the pump can be calculated using the following formula:
Actual flow rate = Actual displacement / (1000 × 60)
= 9.174 LPM
Volumetric efficiency of the pump can be calculated using the following formula:
Volumetric efficiency = Actual flow rate / (Q × Theoretical displacement / (1000 × 60))
= 9.174 / (1800 × 305,798.14 / (1000 × 60))
= 0.94 or 94%
Therefore, the volumetric efficiency of the pump is 94%.
121.
A gear pump has an outside diameter of 80mm, inside diameter of 55 mm and
a width of 25mm. If the actual pump flow is 1600 RPM and the rated pressure is 95
LPM what is the volumetric displacement and theoretical discharge
Outside diameter of gear pump (D) = 80mm
Inside diameter of gear pump (d) = 55mm
Width of gear pump (W) = 25mm
Actual pump flow (Q) = 1600 RPM
Rated pressure (P) = 95 LPM
Theoretical displacement of the pump can be calculated using the same formula as in
Exe.5:
Theoretical displacement = (π/4) × (D² - d²) × W
= (π/4) × (80² - 55²) × 25
= 262,958.17 mm³/rev
Volumetric displacement of the pump can be calculated using the following formula:
Volumetric displacement = (Q × 1000) / (60 × RPM)
= (95 × 1000) / (60 × 1440)
= 0.110 L/rev
Theoretical discharge can be calculated using the following formula:
Theoretical discharge = Theoretical displacement × RPM / 1000
= 262,958.17 × 1600 / 1000
= 420,732.67 mm³/min
= 0.421 L/min
Therefore, the volumetric displacement of the pump is 0.110 L/rev and the theoretical
discharge is 0.421 L/min.
122.
A gear pump outside diameter of 100 mm & having modules of 4mm & 20
degree angle & 20mm width. It delivers 80Lpm oil while operating at 1800 rpm. At
pressure 10Mpa. The actual torque of the prime mover is 100Nm. Determine:1)
OverallEffi .2)TheoroticalTorque
Given:
Outside diameter, D = 100 mm
Module, m = 4 mm
Pressure, P = 10 MPa
Width, b = 20 mm
Actual flow rate, Q = 80 LPM
Speed, N = 1800 RPM
Actual torque, T = 100 Nm
Theoretical discharge can be calculated as:
Qth = (π/4) * (D^2) * N * ηv
where ηv is the volumetric efficiency.
Volumetric displacement can be calculated as:
Vd = (π/4) * (D^2) * m * b
Actual discharge can be calculated as:
Q = Qth * ηo
where ηo is the overall efficiency.
We can rearrange the above equations to get the required values.
Calculating volumetric displacement:
Vd = (π/4) * (100^2) * 4 * 20 = 125663.71 mm^3
Calculating theoretical discharge:
Qth = (Q/ηv) = (80/0.96) = 83.33 LPM
Calculating overall efficiency:
ηo = (T * N) / (2 * π * Q * P) = (100 * 1800) / (2 * π * 80 * 10^6) = 0.078 or 7.8%
Calculating theoretical torque:
Tth = (2 * π * Qth * P) / N = (2 * π * 83.33 * 10^-3 * 10^7) / 1800 = 231.84 Nm
Answer:
Overall Efficiency = 7.8%
Theoretical Torque = 231.84 Nm
123.
An Axial Piston pump having nine cylinder have 15 mm dia. Arrange 150 mm
p.c.d. They are operate data speed of 3200 rpm & deliver 190 Lpm atrated pressure.
Calculate the volumetric efficiency of pump
Number of cylinders, n = 9
Diameter of cylinder, d = 15 mm
Pitch circle diameter, PCD = 150 mm
Speed, N = 3200 RPM
Rated flow rate, Q = 190 LPM
Volumetric efficiency can be calculated as:
ηv = (Q / [(n/2) * (π/4) * (d^2) * N]) * 100%
Answer:
Volumetric Efficiency = (190 / [(9/2) * (π/4) * (15^2) * 3200]) * 100% = 95.5%
124.
The displacement of pumpo perating at 1000 rpm at a pressure of 70 bar is
100cm3. The input torque from prime mover is 120Nm. If it deliver 0.00015 m3/s ec of
oil. Determine 1)overall eff. 2)Therotical Torque 3)Vol. Effi.
Given:
Displacement, Vd = 100 cm^3
Speed, N = 1000 RPM
Pressure, P = 70 bar
Actual flow rate, Q = 0.00015 m^3/s
Actual torque, T = 120 Nm
Theoretical torque can be calculated as:
Tth = (2 * π * Q * P * Vd) / (60 * 10^3) = (2 * π * 0.00015 * 70 * 100) / (60 * 10^3) =
0.219 Nm
Overall efficiency can be calculated as:
ηo = (T * N) / (2 * π * Q * P) = (120 * 1000) / (2 * π * 0.00015 * 70 * 10^5) = 64.9%
Volumetric efficiency can be calculated as:
ηv = (Q / [(π/4) * (d^2) * N * 1000]) * 100%
where d is the diameter of the cylinder.
Answer:
Overall Efficiency = 64.9%
Theoretical