BASIC HYDRAULICS QUESTIONS AND ANSWERS
Pascal's Law - answer-Pressure on a confined fluid is transmitted undiminished in
every direction, acts with equal force on equal areas, and at right angles to the
container walls.
Series Circuits - answer-If cylinders are hooked in series, the pressure required to lift
the first cylinder is affected by the pressure required to life the next cylinder in
series circuit. The resultant pressure is called back pressure.
Bernoulli's Principle - answer-States that the sum of pressures and kinetic energy
(flow) energy at various points in a system must be equal.
Hydraulic Horsepower (hp) - answer-A first principle is that energy in the form of
work is transferred without loss. Power is the Rate of doing work.
Series Circuits - answer-If cylinders are hooked in series, the pressure required to lift
the first cylinder is affected by the pressure required to lift the next cylinder in
series circuit
Schematics - answer-Recognize the purpose and advantages of using schematic
objectives
ANSI - answer-American National Standards Institute
ISO - answer-International Standards Organization
Circles - answer-represents pumps and motors
Squares - answer-Represents valves that can have multiple positions
Diamonds - answer-Represents fluid conditioners such as filters and coolers
Rectangle - answer-Represents cylinders that are single acting or double acting
Open Rectangles - answer-Represents reservoirs
Inline Fixed Displacement Axial Piston Pump - answer-Move on same axis as
driveshaft
Axial Piston Components - answer-retainer ring, ball guide, piston, retainer and
pistons, cylinder block, springs
Servo Piston - answer-has an orifice in it so oil is constantly moving acrossed the
orifice when the pressure is directing the oil
Solids - answer-causes abnormal wear on closely mated parts. Internal leakage
increases efficiency of the pump is lowered
, Sludge - answer-Caused by a chemical reaction of fluid from excessive
temperatures and condensation
Water - answer-causes rust which pits the metals and continues to contaminate the
fluid
Viscosity - answer-The degree that fluid resists flow. A high number fluid is slow
moving and a low number is a fast moving fluid
Cavitation - answer-Fluid does not entirely fill the volume of the pump
Gear Pumps - answer-two gears mesh with each other in a housing driven by
driveshaft. Constant Output
Vane Pumps - answer-Fluid enters and fills area which rotates rotor.
Axial Piston Pumps - answer-increase flow by increasing swash plate angle
Fixed and Variable pumps - answer-fixed pump depends on rpm of motor. Variable
pumps change the output flow by changing the pumps rpm and or swash plate
angle
Pressure Control - answer-1st primary function
Directional Valves - answer-2nd primary function
Volume Control - answer-3rd primary function
Pressure control - answer-pressure limits or set max system pressure.
Poppet - answer-Working part of the valve
Unloading Valves - answer-Direct acting and Pilot operated
Pressure Override - answer-As spring collapses the amount of force required
increases
Direct Acting Relief Valve - answer-low volume, fast operation, less frequent
operation than pilot operated, shocknloads
Pilot Acting relief valve - answer-Often not represented correctly as shown in
schematic diagrams. The pilot valve triggers the main relief
Valve Stacks - answer-Several section of valves stacked together
Unibody Valves - answer-Several valves in one housing. Advantage less leakage
over time
Anti Cavitation - answer-Allows oil from the return passage to join oil in the work
port when required
Pascal's Law - answer-Pressure on a confined fluid is transmitted undiminished in
every direction, acts with equal force on equal areas, and at right angles to the
container walls.
Series Circuits - answer-If cylinders are hooked in series, the pressure required to lift
the first cylinder is affected by the pressure required to life the next cylinder in
series circuit. The resultant pressure is called back pressure.
Bernoulli's Principle - answer-States that the sum of pressures and kinetic energy
(flow) energy at various points in a system must be equal.
Hydraulic Horsepower (hp) - answer-A first principle is that energy in the form of
work is transferred without loss. Power is the Rate of doing work.
Series Circuits - answer-If cylinders are hooked in series, the pressure required to lift
the first cylinder is affected by the pressure required to lift the next cylinder in
series circuit
Schematics - answer-Recognize the purpose and advantages of using schematic
objectives
ANSI - answer-American National Standards Institute
ISO - answer-International Standards Organization
Circles - answer-represents pumps and motors
Squares - answer-Represents valves that can have multiple positions
Diamonds - answer-Represents fluid conditioners such as filters and coolers
Rectangle - answer-Represents cylinders that are single acting or double acting
Open Rectangles - answer-Represents reservoirs
Inline Fixed Displacement Axial Piston Pump - answer-Move on same axis as
driveshaft
Axial Piston Components - answer-retainer ring, ball guide, piston, retainer and
pistons, cylinder block, springs
Servo Piston - answer-has an orifice in it so oil is constantly moving acrossed the
orifice when the pressure is directing the oil
Solids - answer-causes abnormal wear on closely mated parts. Internal leakage
increases efficiency of the pump is lowered
, Sludge - answer-Caused by a chemical reaction of fluid from excessive
temperatures and condensation
Water - answer-causes rust which pits the metals and continues to contaminate the
fluid
Viscosity - answer-The degree that fluid resists flow. A high number fluid is slow
moving and a low number is a fast moving fluid
Cavitation - answer-Fluid does not entirely fill the volume of the pump
Gear Pumps - answer-two gears mesh with each other in a housing driven by
driveshaft. Constant Output
Vane Pumps - answer-Fluid enters and fills area which rotates rotor.
Axial Piston Pumps - answer-increase flow by increasing swash plate angle
Fixed and Variable pumps - answer-fixed pump depends on rpm of motor. Variable
pumps change the output flow by changing the pumps rpm and or swash plate
angle
Pressure Control - answer-1st primary function
Directional Valves - answer-2nd primary function
Volume Control - answer-3rd primary function
Pressure control - answer-pressure limits or set max system pressure.
Poppet - answer-Working part of the valve
Unloading Valves - answer-Direct acting and Pilot operated
Pressure Override - answer-As spring collapses the amount of force required
increases
Direct Acting Relief Valve - answer-low volume, fast operation, less frequent
operation than pilot operated, shocknloads
Pilot Acting relief valve - answer-Often not represented correctly as shown in
schematic diagrams. The pilot valve triggers the main relief
Valve Stacks - answer-Several section of valves stacked together
Unibody Valves - answer-Several valves in one housing. Advantage less leakage
over time
Anti Cavitation - answer-Allows oil from the return passage to join oil in the work
port when required
