Chapter 4 Flashcards
Valves
A mechanical device consisting of a body and a moving part which connects and disconnects passages within the body
Control of pressure
Pressure must be co trolled at 2 points. At the compressor and after the receiver tank
Pressure switch
Pressure control device that can turn on and off anything electrical
Safety relief valve
Valve that opens Incase of system failure. Used for safety. Pressure acts on an area creating enough force on the area to overcome the spring to release excess pressure
Pressure regulator
Controls downstream pressure. Limits flow to limit pressure. Pressure acts on an area creating enough force on the area to overcome the spring to stop excess pressure from being released
Double acting cylinder
Causes power reversible motion. Has a port at each end of the cylinder where air under pressure can enter or exit.
Flow control valve
Any needle valve that affect the actuator speed by a restriction. Go at or as close to the cylinder as possible
Reasons we use valves
System pressure, direction of flow, and rate of flow
Detent
A holding device to help keep the moveable member in the desired shifted position
Directional control valve (dcv)
Used to change the direction of airflow to and from the cylinder.
2 way dcv
Main function is on and off. 2 ports connected to each other with passages that are connected and disconnected
3 way dcv
Main function is to pressurize and exhaust one actuator port. 3 ports connected through passages
4 way dcv
Main function is causes power reversible motion. Pressure ports 2 actuator ports and 1+ exhaust ports.
Categories of a dcv
Positions- (2 min) forward, reverse, and park
Ways- (2-4) in, out, and exhaust.
Operated- manually, mechanically, electrically, and pilot pressure
Returned- spring and blocked
Center conditions
Blocked (stoped), pressure (forward), and exhaust (reverse)
Air flow is rated in
Cubic feet per min
