Yes it’s relatively easy to achieve. First thing is flow measurement sensor needed and then a flow control valve, butterfly valve does ok. Just watch that the air flow signal will be quite noisy as the vortex rises and falls so use a fair amount of filtering. You will need to seal around the air intake with a box of some sort unless there is an air intake already built into mechanism. For a 120 I think a minimum of 75mm air intake pipe should do it, any smaller and you'll restrict airflow, so keep pipe short too.

Good answer! Butterfly valve is the right choice and is normally part of the Wemco supply (as a manual valve). The air intake would need to be extended to allow actuation of the valve, but I cannot think why anyone would want to do this, as the air flow is regulated as a function of a cell behaviour, which needs to be seen to be understood. If you can see the cell behaviour, you are there to regulate the air flow - you only need to extend the air intake handle. Automation of flotation variables is only feasible with consistent mineralogy and feed rate (tonnes & solids concentration).

You can use Hontzsch and GEFA make thermal air flow sensor and pneumatically actuated butter fly valve and needs to be PID programmed on PLC. Converting a self-aerated cell to sub aeriated cell, need may arise to play in the cell RPM also.

Self-aeriated cell suck the air from the atmosphere through a hole provided on the top plate of drum- agitator assembly. It can regulate with V notch opening on circular rubber sheet cover cell by playing in the opening area. 

Thanks all for the feedback. We were indeed thinking a butterfly valve, but pondering the flow measurement due to concerns regarding flow restriction. This is somewhat of an experimental modification (on a single bank) that is complementary to other adjustments being made. I see no evidence that the agitators are flooded at current operating regime, so first purpose would be to measure the aeration rate - whether we actually reduce it, and whether this is done automatically would depend on the outcome of test work. We did mount cameras that provide continuous visual feed to the control room given that so much of flotation control depends on the appearance of the cell. We have adjusted RPM's in the past to try and compensate for the wide range of particle sizes reporting to flotation - we may revisit the RPM's depending on the follow-up test work.