Hydraulic Valves Flashcards
What Valve is this?
Pilot Operated Relief Valve
What is this Valve?
What is it used for?
Unloader Valve
Relieving the pump when circuit pressure is reached.
What Valve is this?
What purpose does it serve?
Brake Valve
This valve prevents the load from overrunning the actuator, a motor in this case.
What valve is this?
Direct Acting Relief Valve
What Valve is this?
How does it function?
What kind of Pump is used on this system?
3 Position, 4 Way
Closed Centre, Open Port
Directional Control Valve, with a Fixed Displacement Pump & Unloader or Pressure Compensated Variable Displacement Pump.
Also called a Motor or Float Spool Valve, allows use of brake valves in the circuit the same as the Open Centre Open Port Valve but this differs by blocking flow from Pump and Tank.
What Valve is this?
What purpose does it serve?
Line Lock Valve
(Double Pilot Line Lock)
These valves prevent a load from moving an actuator unless pressure has been provided. Incoming pressure on either Port A or B will open a checkball shfiting a spool to open the check on the opposite side allowing return oil through the valve.
What Valve is this?
How is it used?
Throttle Valve
This is installed in series of a line to restrict flow and adjust pressure according to the amount of restriction to flow.
What Valve is this?
Where is it used?
How does it function?
Three Position, Three Way
Directional Control Valve
Used with single acting cylinders, functions to provide a raise hold and lower function, while still using a fixed displacement pump. All Open Centre valves will be using a fixed displacement pump.
What Valve is this?
How does it function?
Two Position
3 Way
Directional Control Valve
Sometimes called a Diverter Valve,
direct flow to one circuit or the other.
What Valve is this?
What purpose does it have?
Counterbalance Valve
Prevents a load from overrunning an actuator during operation.
What Valve is this?
What purpose does it serve?
Pressure Compensated
Restrictor Type Flow Control Valve
Maintains a pressure difference across itself by reducing flow in relation to pressure changes on inlet and outlet.
What Valve is this?
What purpose does it serve?
Pressure Compensated Bypass Flow Control Valve
Maintains a constant pressure difference across itself and dumps excess to tank. Pressure is balanced by
What Valve is this?
How does it function?
What type of Pump would be used on this system?
3 Position, 4 Way
Open Centre, Closed Port
Directional Control Valve, Fixed Displacement Pump
This prevents the A and B ports from draining, providing a hold condition for the actuator.
What valve is this?
What purpose does it serve?
Pressure Reducing Valve
This valve reduces line pressure by modulating itself on/off to drop pressure. These are used in circuits to allow a lower pressure than system pressure for certain actuators.
What Valve is this?
How does it function?
What sort of Pump would be used in this system?
3 Position, 4 Way
Closed Centre, Closed Port
Directional Control Valve, used with a Fixed Displacement Pump and Unloader Valve or Pressure Compensated Variable Displacement Pump.
These Valves provide a hold condition for the actautor and block flow from Pump to Tank on the Valve.
What Valve is this?
How does it Function?
What kind of Pump would be used on this system?
3 Position, 4 Way
Open Centre, Open Port
Directional Control Valve, with a Fixed Displacement Pump
These valves can be called a Motor Spool or Float Centre. These valves allow the use of brake valves down the circuit to hold a load where if it were closed port the load pressure would blow the control valve apart.
What Valve is this?
What purpose does it serve?
Sequence Valve
It causes actuator functions to follow a certain order.
