PTS Flowbench Forum

i am currently building an orifice style flow bench and all the pics of others ive looked at show a hole or some bottle neck after the orifice plate before the vacuum source like a 5 or 6 inch hole is this just to make sure to pull the air directly from under the orifice plate or is there something else to this? thanks

If your flow bench is required to flow in both directions (both blow and suck) through the test piece, then some type of air reversing system is required.

Many people here use a series of fairly large holes with a sliding plate that changes the flow direction through the bench, by blocking/uncovering a combination of holes.

I strongly suggest you purchase a set of flow bench plans from Bruce.
It will answer all your questions, is a very well proven design, and will save you a lot of time and money in the long run.

I didn't mean the flow direction chamber just that I usually see a hole like 5-6" under the plate in the bottom chamber with a ate over it much like the entry/settling chamber entrance.

Who's flowbench has something like that?

Have a picture of what you are referring to?

A 5 or 6" hole is not going to be much of a restriction on a 600cfm@28" bench if you do the math