Midterm Flashcards
Description of DCV
Number of blocks are positions
Number of lines are ways
Formula of Pressure
Force over area
Unbalanced came pump
Circular chamber and adjustable
Balanced vane pump
Egg shaped and not adjustable
Displacement of pump
Affects the velocity of the piston in the cylinder
Vane pumps
Doesn’t tolerate containaments
Low to med displacement
Low pressure resistance
Piston pumps
Most efficient volumetric flow
Typical odd number of cylinders
Variable swash plate piston pump
Allows adjustment of displacement
Reservoirs
General designs have 1/3 to 1/2 of fluid in system
P and T
Pressurized fluid and tank fluid
DCV
Named after design and features
They direct and exclude flow
PRV setting
Set 10% higher than max operating pressure
Extension formula
Area piston x stroke
Hp formula
Prel x Del x .000583
Divide by V.E.
Inlet velocity
2 to 5 ft/sec
Working velocity
7 to 20 ft/sec
Working diameter
Square root of (del x .3208) / ( vel x .7854)
Inlet diameter
Square root of (del/v.e x .3208) / (vel x .7854)
Delivery formula
Supply rate x 1/231
Designing regenerative circuits
Should only base calc on annulus area
Telescoping cylinders
Speed up as it extends
Multiple piston cylinders
2 Pistons attached to one rod
Most common check valves
Ball and poppet
Fluid cushion
Used for big and high velocity app that slows it down for no metal to metal contact
Shunt
Exhaust for fluid that uses check valve
Open center valve
Used to conserve energy
Tandem center DCV
Allows pressure to be held in system while you conserve energy
