Valves - Part B Flashcards Preview

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Flashcards in Valves - Part B Deck (12)
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1
Q

Proportional valves

A
  • solenoid operated valve that proportionally controls movement of the spool with electrical inputs.
  • adjusting electrical energy to meter the flow
  • pay attention to the diagonal arrow and the flow symbol on the drawing
  • metering notches to smoothly and accurately control flow
2
Q

Amplifiers

A

-dead band, gain, dither signal, ramp functions

2
Q

Dead Band

A

-boosts the signal to make the spool jump quickly across the overlap distance

3
Q

Gain

A

-the number of times that the output voltage is greater than the input voltage

4
Q

Dither Signal

A

-small, high frequency alternating current that is applied to the solenoid

5
Q

Ramp functions

A

-control how fast the voltage to the solenoid is increased and decreased

6
Q

Three amplifier systems

A
  • open loop (sees if the actuator is responding)
  • closed inner loop (position of spool)
  • closed outer loop (knows where actuator is and can correct it - most efficient)
7
Q

Stacking valves

A

-have ports that have o-ring seats to seal the connections between one valve and the next

8
Q

Cartridge valves

A
  • screw in (low flow, disposable)

- slip in (larger flow and can be repaired)

9
Q

Transducers

A

-pickups or sensors for servo valves that measure position, pressure or velocity

10
Q

Hysteresis

A

In servo valves-(inconsistent spool movement) expresses how accurately the spool moves compared to the input current

11
Q

Six devices for signal input to amplifier cards

A
  • joystick
  • potentiometer
  • PLC
  • tach generator
  • pressure transducer
  • temperature sensor