Flow, Max Pressure & Peep Valves - BIO-MED DEVICES CROSSVENT-3+ Operation & Service Manual

IX. MAINTENANCE AND SERVICE- cont.
8. FLOW, MAX PRESSURE & PEEP VALVES 8. FLOW, MAX PRESSURE & PEEP VALVES
8. FLOW, MAX PRESSURE & PEEP VALVES 8. FLOW, MAX PRESSURE & PEEP VALVES
1. Remove the rear panel, battery, front bezel and PCB. In lieu of removing the PCB, the Pneumatic
Valve Bracket assembly can be removed to access the valves.
2. FLOW VALVE
WARNING: Any time the flow valve(s) are disturbed, the flow calibration in
the CAL menu must be performed.
section.
a. From the rear of the unit, cut the tubing from the flow valve barb to the Regulator/Pilot Valve.
Take care not to damage or nick the barb.
b. From the front, rotate the gear on the Flow Valve until the setscrews can be accessed. There
will be two setscrews per hole, one on top of the other, for a total of four. Remove the top
setscrews and then loosen the ones underneath. Remove the gear.
c. Remove the retaining nut and washer from the front of the valve.
d. Slide the valve towards the potentiometer to disengage the brass connecting tube to the DARV
Manifold and remove the valve.
e. To replace the valve, first turn the valve shaft CW until slight resistance is felt indicating it is
closed and place a very light film of oxygen-safe grease on the o-ring at the end of the
connecting tube. From the rear of the bracket, insert the valve shaft through the open slot in
the bracket and position the valve so the raised shoulder on the front of the valve is in the slot
and the brass connecting tube is aligned with the hole in the side of the DARV Manifold.
f. Slide the valve towards the DARV Manifold so the o-ring on the brass connecting tube engages
the hole in the DARV.
g. Place the washer over the threads on the front of the valve and then thread on the nut loosely
so the valve can still be moved within the slot.
h. The valve must now be positioned in the slot for proper engagement with the gear on the
potentiometer.
tighten one setscrew just enough to hold the gear in place.
i. To aid in establishing an acceptable engagement of these two gears, place a small strip of paper
(standard copier paper approx. 5-6 mil thick) between the gears and slide the valve towards the
potentiometer until the gears mesh snugly with the paper formed around the teeth between
them.
j. Hold the valve in this position within the slot, remove the gear and tighten the retaining nut.
Be careful the valve does not move within the slot.
k. Remove the gear from the potentiometer shaft.
setscrews per hole, one on top of the other, for a total of four. Remove the top setscrews and
then loosen the ones underneath. Remove the gear.
l. Rotate the Flow Valve shaft 180° CCW from the closed position.
m. Position the gear on the shaft so that the setscrews are at the top (approximately 11 & 1 o'clock
positions) and secure the gear to the shaft by tightening the setscrews and replacing the second
setscrews. Turn the valve CW back to the off position. The setscrews should now be at the
bottom.
n. From the Pilot Valve, remove the remaining clear tubing that was previously cut from the Flow
Valve. Be careful not to damage or nick the barb.
o. Replace this tubing between the Pilot Valve and Flow Valve with a new piece and tighten a
cable tie around each barb for added security.
p. To properly secure the potentiometer gear to the valve shaft, refer to the Pneumatic Calibration
section and perform Flow Valve/Potentiometer Zero, skipping the "To Test" and going right to
the "Calibrate as follows" section. Once this has been completed, reassemble the rest of the
unit and then proceed to the Flow Calibration in the Pneumatic Calibration section.
3. ENTRAINMENT FLOW VALVE
a. Only do this step if the valve is to be replaced. Carefully cut each of the 9 tubes from the valve
to the venturi block at the block end. Cut the supply tube at the elbow in the rear of the valve.
b. From the front, rotate the valve gear until the setscrews in the gear can be accessed. There will
be two setscrews per hole, one on top of the other, for a total of four.
setscrew and then loosen the one underneath. Remove the gear.
c. Remove the nut and washer and remove the valve from the bracket.
d. If the tubing to the venturi block was cut in step b, then carefully remove any remaining tubing
from the barbs on this block. Do not nick or damage the barbs in any way while doing this
(refer to Fig. 16 in Preventive Maintenance Kits later in this section).
e. Before installing the new valve, locate the line or mark on the side of the valve. This indicates
the #1 port, which is the barb adjacent to this mark. Install the valve into the bracket so this
mark is facing the battery compartment (facing up).
Place the Flow Valve gear on the shaft of the Flow Valve and temporarily
Refer to the Pneumatic Calibration
Within the gear teeth there will be two
Remove the top
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