Low oxygen pump start-up current setting triggers trip interlock
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For Air Liquide’s 64000 air separation unit, in the nitrogen pressurization cycle, if the current does not reach 217A 60 seconds after the liquid oxygen pump starts, the pump fails to start. What is the reasoning behind such a setting? Also, if the outlet pressure does not reach 3 Mpa within 60 seconds of startup, the pump will also shut down. What is taken into consideration here? Is it really necessary? The oxygen pump is a Coromant pump
Prevent cavitation in the liquid oxygen pump, which could otherwise cause damage to the pump~~ Large current fluctuations or a low level of current, severe pressure fluctuations, and significant vibration in the outlet pipe are all typical signs of cavitation~~
What was said upstairs is correct; it’s all to protect the pump. If phenomena such as cavitation or blockage of the pump’s inlet filter occur, the pump will not operate properly, with low outlet pressure and low current. Blockage of the inlet filter can still be managed to some extent, but cavitation can cause severe damage to the pump.
1. Cavitation often occurs during startup, and the main priority is to protect the equipment at the moment when cavitation appears in liquid pumps. 2. Use current to determine whether the liquid pump starts properly. 3. Determine the start time of the liquid pump by checking whether the outlet pressure reaches above 3 MPa; if not, treat it as cavitation. Stop the pump.
I’ve learned about this. It’s the first time I’ve heard of such a interlock mechanism; it’s probably designed by the manufacturing process to protect the liquid oxygen pump equipment. The Cryomac oxygen pumps I used before didn’t have such an interlock, but it would definitely be included if the equipment requirements demanded it.
The settings may not be very practical in real life, but protecting the equipment is definitely of top priority. This requires exploring the actual parameters for each set of equipment in order to configure it. If 30 seconds is not enough, it can be increased slightly based on the actual value.