1.3 Pressure Control Flashcards
Cracking Pressure
The pressure at which the valve begins to divert flow
Full Flow Pressure
The pressure at which the valve starts dumping the full output of hte pump back to the tank
Pressure Override
The difference between flull flow pressure and cracking pressure
What type of PCV?
Relief Valve
Placed at the pump outlet to protect the pump from excess pressure.
What type of PCV?
Unloading Valve
Two pumps may be used in parallel to quickly charge the circuit. Once the pressure reaches threshold, the unloading valve will relieve the fluid from one of the pumps so that only one pump is charging the circuit but the other is still running and able to take over as soon as the pressure drops. The direction of the arrow here is wrong.
What type of PCV?
Pressure Reducing Valve
Normally Open, hence the pressure is measured after the valve. Ensures the pressure remains below 100psi. Placed before the load.
What kind of valves? What does this circuit do?
Left: Unloading Valve
Right: Relief Valve
Excess pressure is diverted to the sump.
What kind of valve? What does this circuit do?
Pressure Reducing Valve
Reduces the pressure to 100psi before the load.
What type of PCV?
Sequence Valve
These are normally closed and so they must measure before the valve.
What type of PCV? What does this circuit do?
Sequence Valve
This sequences the pistons one after the other.
What type of PCV?
Counterbalance Valve
Normally closed, prevents a weighted linear actuation. Lets out only enough fluid to maintain pressure at the valve setting.
What type of PCV?
Counterbalance Valve
This circuit counters a pison lowering on retraction.
What type of PCV does this use? What does this circuit do?
Counterbalance Valve
Resists the piston lowering.
What type of PCV?
Brake Valve.
Motor exhaust is restricted
What type of valve does this use? What does this circuit do?
Brake Valve
Motor Braking
