SpudFiles

For an off-the shelf valve, I gather the QEV (old threads imply harder to get) and the Pulse dust clearing valves (e.g. those from Asco) are good options.

But I have been unable to figure out how to model them in GGDT. Anyone have any sample parameters they can share? Are these both Chamber seal types? Or should I use "generic"? In the case of generic, I don't knwo what to use as response time.

Grateful for some assistance here... I assume Mr. Hall is no longer with us.

I typically use "generic" as a good approximation, for exhaust valves typically opening time is a matter of milliseconds so say 5 ms should give you typical results.

(old threads imply harder to get)

Not at all, they are all over Amazon or eBay and cheaply available, unless you need larger diameters in which case they start getting a little pricey.