Valves Flashcards
Control valve that selects the ROUTE (Directional Control) of flow of fluid through the system
can be manually, electrically, and hydraulically operated.
Flow Control valve
Control valve that adjusts, Regulates or Limits the amount of PRESSURE in a system or sub-system
Pressure Control Valve
Valve that determines, DIRECTION OF FLUID FLOW and controlled by the PILOT or automatically by the system.
direct fluid flow from the pump to one side of the actuator and direct fluid on the other side of the actuator back to the reservoir (return)
Selector valves
When the hydraulic component is not being actuated and the SV is in the ‘OFF’ position, fluid flow is directed through the centre of the Selector Valve and back to the reservoir
Open Centre - Selector valve
AKA Neutral or Shut - off position, system pressure is controlled independently by valve positions.
fluid is directed through the SELECTOR VALVE to one side of the actuator while fluid on the other side of the actuator is routed thru the Selector Valve’s return port (flow to reservoir)
Closed Centre - Selector Valves
Two systems application are:
Open and Close Center
3 Types of valve:
POPPET
ROTARY
SPOOL
Type of valve that is controlled by a CAM or SERIES OF CAMS that are all positioned by a control handle and can be used in both open and close centre.
Hydraulic pressure or springs close the valves and control - handle rotation opens the valves.
POPPET Selector Valve
Type of valve that consist a rotating cylinder inside the valve, pressure and return ports are on opposite ends
can be used both close and open-centre systems.
rotating the handle 90 degrees directs the pressure to the opposite side of the actuator.
ROTARY Selector Valve
Flow selector valve that consists of a sliding spool (SLIDING PISTON)
can meter the fluid flow by controlling the amount the spool covers the pressure outlet
Spool Selector Valve
2 designs of check valves:
INLINE (self-contained)
INTEGRAL (part of another unit sharing the same casing)
