16
CORN I NG ASCENT FBR PD SYSTEM
NOTE:
The white tubing clip is always positioned next to the instrument, while the black tubing clip is on the outside.
Figure 5-25.
Pinch valve locations. Refer to Table 5-9 for descriptions.
Figure 5-26.
A pinch valve close-up. The cover label
shows where to align and load the tube lines based
on the tubing clip color.
5.4.1 Pinch Valve Positions
Valve positions are important for directing tubing flow when the system calls for it. Each pinch valve secures tubing in two valve positions:
top or bottom. Both top and bottom valve positions have plungers programmed to actuate – raised or retracted, depending on where
media is directed. The top valve position, denoted by a black bar on the pinch valve cover, is farthest from the instrument. The bottom valve
position, denoted by a white bar on the pinch valve cover, is closest to the instrument.
When the system powers on, the pinch valves are not energized. At the de-energized state, the bottom valve plunger is designed to extend
while the top valve plunger is retracted (Figure 5-27). Tubing load takes place when the pinch valves are de-energized. The user shall load
tubing in the bottom valve position first followed by the top valve position.
Once a phase is started on the HMI, the pinch valves are energized. The top and bottom valve plungers actuate accordingly depending on
media direction.
Figure 5-27.
A de-energized pinch valve at power-up. The top valve plunger is retracted to allow uninterrupted tubing flow.
The bottom valve plunger is raised to constrict the bottom tubing.
