Technical Term for a Valve?

How about a solenoid valve. Electrical operation for either fully open or fully closed.

http://en.wikipedia.org/wiki/Solenoid_valve

That's what we use for controlled bursts of compressed air.

Its called a blow off gun.

You may also want to consider using what is called a "dump-valve". Usually a diaphram valve that can dump an extremely large charge of compressed air very quickly.

This is correct! A dump valve or "blow-off" valve are made to reach maximum Cv in minimum time.

Try using a quarter turn butterfly or Plug valve. Depending on the media you may use TFE or rubber seated valve of either variety

MANECK

Hello Mr. Tridens!

I wonder where you will use such kind of valve. In the Coffee Industry, specifically in the extraction stage, we have such kind of valve which we call a "Blowdown Valve".
It is a plug type full-bore valve that is pneumatically activated. The size of the valve will determine if you can do a manual opening or closing. If you have a one inch pipe or smaller, perhaps you can do it manually, but for bigger sized pipes, at that high pressure of 400psi, it might be quite an effort to do a manual opening and closing.

"I'm looking for a manual valve that can handle about 400 PSI on the supply side."

Ball Valve?