190301b hydraulic pump fun Flashcards
Are vane pumps balanced or unbalanced?
Depending on Cam style they will be balanced or un balanaced
Hydraulic pumps convert what energies?
Mechanical energy to Hydraulic energy
Where does a pump gets its power from?
Prime mover (internal combustion engine or electric motor
What does a pump supply for our system?
Fluid flow
What determines direction of rotation?
The mechanical energy source, the pump will be connected to it via a shaft
On a gear pump how many drive gears are there?
one will be the drive from prime mover and the other will be driven
Is pump displacement directly related to the pump’s internal volume?
Yes
How do we express pump displacement?
cm³/rev or in³/rev
Are gear pumps fixed displacement only?
Yes
Describe fixed displacement?
pumping chamber will deliver the same amount of fluid with every revolution
Is the input of a gear pump the low pressure side?
Yes
Are all vane pumps fixed displacement?
No they can also be variable
What are the three types of piston pumps?
Axial, Bent Axial and radial
What must be included to make a vane pump variable displacement?
Displacement control and maximum volume adjustment, adjust circular cam position
In an axial piston pump, are the pistons parallel or 90° to the drive shaft?
Pistons are parallel
Are radial piston pump’s pistons parallel or 90° to the drive shaft?
90°
What does maximum swash plate angle create in a piston pump?
The result is maximum flow
Since a bent axis piston pump has no swash plate what needs to move to change displacement?
lens plate
rotating members
What style of vans are needed to create a gradual start up?
Spring pressure on bottom of vane
Generally what RPM does the vane pump need to rotate to use centrifugal force to push the vanes out?
600 RPM
How many pieces of make up a vane pump house?
2 or 3 piece
In a three piece vane pump house what is the middle piece?
The cam
What are the two styles of cam rings in a vane pump?
Circular or elliptical
What is used in a reversible gear pump to allow auto changes in flow direction?
Check balls
What determines the amount of fluid flowing internally through a pump?
The pressure difference between inlet and outlet ports
The amount of internal clearance with the pump
What limits the internal leakage in a external gear pump?
Pressure plates
Rounded vane tips must be installed in the correct direction?
The direction of the rotor rotation does not change the way rounded vanes are installed
What is generally the Volumetric efficiency of a external gear pump?
85-87% VE
If you have a faulty shaft seal on a external gear pump, what would be the result?
Aeration
What is the operator complaint if aeration is occurring?
Spongy operation
Why do we need internal leakage in our pumps?
Lubricate all parts
How do you determine the inlet port on an external gear pump?
Usually larger
Gears will be coming out of mesh
Bi Directional Gear pumps can be installed what way?
In an application that is either clockwise or counter clockwise shaft rotation. (without performing any internal modifications)
What is common on a bi direction gear pump?
Hint: Ports
Ports are generally the same size
What is the vane style that has a small cut away in it that allows pressure to act on the underside of the vane?
Intra Vane Design
What pressure is applied to the intra vane?
Outlet pressure
What are the holes in the cam on a vane pump called?
Transfer Slot Input
What is on the back side of a pressure plate to provide pressure?
Outlet oil pressure
Some have a spring to apply force during start up
To change direction on a uni directional pump what is required?
Disassemble the pump and re position internal components
true or false? The greater the pressure difference between the pump’s inlet and outlet port, the greater the amount of internal leakage?
True
Define Slip
Oil leaking from the outlet side of a hydraulic pump to the inlet side
What decreases when pump slip increases?
Efficiency decreases
What can decrease volumetric efficiency?
too much pump wear, internal leakage increases
How is overall efficiency determined?
Comparing input power to output power
What is the pump style that can handle the most contamination?
External gear pumps
