Does a valve like this exist?

I'm here on behalf of medical device startup. Our device involves a large, rapidly inflating/deflating bladder of air. We need a motorized valve with a high throughput at low pressure: hundreds of liters per minute at 5 PSI. Something in the range of 40Cv, or the equivalent of a 1.5" unobstructed pipe, should do the trick. Speed is key: the valve must be able to fully actuate in under 50ms. Weight and volume are also considerations, especially weight. One thing that can be sacrificed is manufacturing tolerance: this valve will not be relied on to stay closed for extended periods, nor will it be working with gases other than air, so some leakage is acceptable.

I have looked at a couple dozen online catalogues, and didn't find anything that meets this description. It's a big world, and I have trouble believing that nobody has had such a need before. Are we looking in the wrong places, or searching with the wrong terminology? Is there some simple oversight in our design?

Thanks for any direction,
Aidan Paradis