AwiDESULF combi-package for microbiological desulphurisation
in the room, a hazardous atmosphere may form outside the suction point.
We therefore recommend
installation in a sufficiently ventilated room.
If a hazardous atmosphere may arise in the suction chamber due to the pressure conditions, pipe
length, pipe diameter, and ventilation conditions, we recommend that the function of the non-return
valve and/or the solenoid valve be checked regularly.
Possible diagnostic options include:
– Shut down the compressor and check for gas leakage at the air intake opening.
– Removal of the non-return valve and visual inspection
– Evaluation of the opening and closing sound of the non-return valve and the solenoid valve.
– Assessment of noise and presence of intake vacuum
– Disassembly of the hose and checking the methane concentration on the air side of the non-
return valve.
– Checking the oxygen concentration in the fermenter: if the set point of the controller is
permanently exceeded (due to a valve malfunction) or not reached at all (due to failure of the
compressor).
An active application of negative pressure is not recommended, because this can temporarily suck
back the ball of the non-return valve in the event of another malfunction and a permanent functioning is
simulated.
Awite's suggested method for checking the non-return valve is:
1. Shut down compressor
2. Immediately afterwards check for gas flow or measure methane concentration
3. Continue checking/measuring for 100 seconds (1 switching cycle)
4. Restart compressor
At 2. to 3. no gas flow (detection limit 0.1 liter per second) and/or no methane may be detected
(detection limit 1000 ppm). The gas flow can also be checked qualitatively (moisten fingers or use
foam).
The non-return valve must be removed and cleaned/replaced if necessary.
A detailed risk assessment can be obtained from Awite upon request.
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