K
Dear All,
I would like to share my experience and troubles i am facing in my current project. (NGL Recovery Unit).
1- we are using control valve with FF type positioners (Masoneilan FVP-110). we have 2 kind of actuators Air to Open (ATO) & Air to Close (ATC). All valves with ATO actuators are working normally with FVP-110 but all valves with ATC actuators, there positioner is acting reverse:-
for example:
Case-1 (ATO)
1.1 For ATO (NC) at fully closed condition we are getting 0% and fully open condition we are getting 100%;
1.2 Scale movement is from fully closed to fully open (0, 25, 50, 75, 100) downward to upward.
1.3 Means when we connect air supply and start giving signals from 0% -> 100% valve stays close at 0% and starts moving according with the input signals from down to up (Close to Open)
Case-2 (ATC)
2.1 For ATC (NO) at fully open we are getting 100% and fully closed condition we are getting 0%;
2.2 Scale movement is also from fully closed to fully open (0, 25, 50, 75, 100) downward to upward.
2.3 Means when we connect air supply and start giving signals from 0% -> 100% valve immediately go to the fully closed at 0% and starts moving according with the input signals from down to up (Close to Open)
In that scenario the section 1.3 & 2.3 are acting in same way,
So, now my understanding is that in FF type positioners no matters whatever is actuator function ATO (NC) or ATC (NO), whenever we gives 0% signal valve stays or moves to fully closed condition.
The case-1 is considered as direct acting and case-2 is considered as reverse acting.
As per actual project requirement; we want ATC (NO) valves in the way as below:
when we connect air supply and inject 0% signals valve should stay open and starts moving from fully open position to fully close position according with the increase in signals; means from up-> down.
If any one can helps me regarding this ,I will be very thankful,
Regards,
Kazim
I would like to share my experience and troubles i am facing in my current project. (NGL Recovery Unit).
1- we are using control valve with FF type positioners (Masoneilan FVP-110). we have 2 kind of actuators Air to Open (ATO) & Air to Close (ATC). All valves with ATO actuators are working normally with FVP-110 but all valves with ATC actuators, there positioner is acting reverse:-
for example:
Case-1 (ATO)
1.1 For ATO (NC) at fully closed condition we are getting 0% and fully open condition we are getting 100%;
1.2 Scale movement is from fully closed to fully open (0, 25, 50, 75, 100) downward to upward.
1.3 Means when we connect air supply and start giving signals from 0% -> 100% valve stays close at 0% and starts moving according with the input signals from down to up (Close to Open)
Case-2 (ATC)
2.1 For ATC (NO) at fully open we are getting 100% and fully closed condition we are getting 0%;
2.2 Scale movement is also from fully closed to fully open (0, 25, 50, 75, 100) downward to upward.
2.3 Means when we connect air supply and start giving signals from 0% -> 100% valve immediately go to the fully closed at 0% and starts moving according with the input signals from down to up (Close to Open)
In that scenario the section 1.3 & 2.3 are acting in same way,
So, now my understanding is that in FF type positioners no matters whatever is actuator function ATO (NC) or ATC (NO), whenever we gives 0% signal valve stays or moves to fully closed condition.
The case-1 is considered as direct acting and case-2 is considered as reverse acting.
As per actual project requirement; we want ATC (NO) valves in the way as below:
when we connect air supply and inject 0% signals valve should stay open and starts moving from fully open position to fully close position according with the increase in signals; means from up-> down.
If any one can helps me regarding this ,I will be very thankful,
Regards,
Kazim