Precision Medical HeliO2 Blenders - Manual (Page 16)

Heliox / Oxygen Blender Service Manual
Page 14
D. Reverse Gas Flow Procedure
(Reference Operational Verification Procedure #’s 2 & 3 in Table, page 15 or 25 .)
1. Disconnect the Oxygen hose from the gas source. Remove all outlet connections from the Blender to
ensure that there is no outlet flow.
2. Place the free end of the Oxygen supply hose under water. Gradually increase the Heliox supply
pressure from 30 - 75 psi (2.07 - 5.17 bar), check for leakage past the Oxygen inlet check valve.
3. Replace the Duckbill Check Valve in the Oxygen inlet if bubbles indicate leakage.
4. Repeat steps 1-3 to check for leakage past the Heliox inlet check valve.
5. Reconnect the Heliox inlet hose and adjust both supply pressures back to standard inlet pressure.
E. Setup of PROPORTIONING VALVE ASSEMBLY CALIBRATION
1. Set Heliox and Oxygen inlet pressures to 50 psi.
2. Set flow to 9 lpm.
3. Turn Adjustment Shaft counterclockwise until the Oxygen Analyzer/Monitor displays a concentration
equal to that of the source Heliox (±0.3), reference Part A in Setup.
4. Attach knob guide assembly onto adjustment shaft of proportioning valve assembly so that the knob
stop rests on top of the screw. Ensure knob stop aligns with the slot in the resistance ring.
5. While applying downward pressure to the 2 screws on the knob guide assembly, attach nut to
adjustment shaft using nut driver.
6. Turn knob guide fully clockwise, Oxygen Analyzer/Monitor display should be equal to concentration of
the source Oxygen (±0.3).
7. Turn knob guide back to 21% position to ensure no drift from original reading (±0.3).
8. Re-attach knob guide, torque nut to adjustment shaft and tighten to 10 in-lbs using a torque driver.
9. Snap in knob back into knob guide, pay close attention to the key location of the knob.
10. Set knob to the 60 graduation.
11. Replace the top cover.
NOTE: DO NOT install the four (4) mounting screws until the end of the Final Test.
F. Final Test
Complete Operation Verification Procedure as per the test table, page 15 or 25 .
Record test results in the test table.
When Final Test is complete replace top cover and install the four (4) mounting screws into cover.
NOTE: Operation Verification Procedure should be performed at least once a year.