Valves Flashcards
The function of valves is to alter, generate and cancel signals for?
Sensing
Processing
Controlling
Supplying working air
What are the 4 main types of valves ?
Non return valves
Directional control valves
Pressure control valves
Flow control valves
What is the purpose and 2 main configurations of the non return valve?
Allow flow in one direction
With a spring return
Without a spring return
What are the 4 types of non Return valves?
Shuttle valve or GATE
Two pressure valve AND GATE
Quick exhaust valve
Time delay valve
What is the purpose of a pilot operated NRV de lockable?
Operate in both directions as and when required
What is cracking pressure?
Is the point at when air pressure overcomes spring pressure of the spring
What is the purpose of a shuttle valve?
Used to select two inputs, if two inputs are applied at the same time the ball valve is moved by the higher pressure to close off the lower input pressure
OUTPUT PRESSURE WILL BE HIGHER OF THE TWO INPUTS
How does a two pressure valve operate?
The highest input pressure will hold the valve across allowing the lower pressure through to the output port
What is the purpose of a quick exhaust valve?
Designed to quickly exhaust pneumatic cylinders
What are the 3 components of a time delay valve ?
Receiver
One way flow control valve
3/2 DCV, pilot actuated
What does the number of squares Indicate on a DCV?
Switch positions
What do the lines indicate on a DCV?
Flow paths
What do the arrows indicate on a DCV?
Direction of flow
What are the 4 methods of valve actuation?
Mechanically
Manually
Pilot
Electronically
What number is the supply labelled?
1
What number is the outputs labelled?
2,4
What number is the exhausts labelled?
3,5
What number is the signals labelled?
12,14
What are the 2 types of pressure relief valves?
Pressure regulating
Pressure relief
What is the position when it’s a pressure relief valve?
Always closed
What is the position when it’s a pressure regulator?
Always open
What do pressure regulators ensure?
Operating pressures at various points remain at a constant pressure regardless of the consumption
How does a pressure regulator operate?
As outlet increases, this pressure acts on a spring with overcomes spring pressure at a set pressure.
This then closes the valve and allows pressure to drop , it then falls back when the pressure is back to sufficient levels
What is the purpose of a pressure relief valve?
Controls or limits the pressure in a system or vessel
How does a pressure relief valve work?
As air pressure rises it acts on a spring which overcomes the cracking pressure , this then allows the valve to open and pressure to leave
What must a pressure relief valve be capable of doing?
Safety valve - must be capable of discharging more air than the system can supply
What is the flow control valve?
Controls the amount of fluid that is allowed to pass through them?
What are the 2 types of flow rates?
Fixed (restrictor)
Adjustable (throttle)
What are the 2 basic method that are used to control valves?
Supply air throttling
Exhaust air throttling
