Azbil Corporation
Model
KFPA
,
KFTA
- Field Mount type Pressure Indicating Controllers
7
Reset unit (integrating unit)
Pneumatic pressure of the feedback chamber is fed to the reset chamber through
capacity and restriction of the reset unit. Thereby attaining a reset action. When the
rate unit is provided, a derivative action also can be attained. A bellows is provided in
the chamber of the rate unit and part of the controller output pressure is directly led to
this bellows to adjust the amplitude of the derivative action.
Other control operations
(a) On-Off action
The nozzle back pressure is directly applied to the pilot relay.
The control operation is done in an ON-OFF mode in response to the open or
closed state of the nozzle.
(b) Differential gap action
The feedback chamber of the controller unit is replaced with a spring-function
device and the output pressure is led to the reset chamber. The differential gap
width is adjustable as required.
Figure 4
Figure 5
Figure 6
Reset dial
Needle
Rate off switch
Feedback
chamber
Control
pneumatic
pressure
Control
pneumatic
pressure
Reset
chamber
Rate dial
Rate
bellows
Reset unit
Rate unit
SP (Index)
SP (Index)
ON
ON
OFF
OFF
Increase
Increase
Operational gap
Operational gap
INC. MEAS.
DEC. OUT
INC. MEAS.
INC. OUT
