PTS Flowbench Forum

Have any of you tried building a bench with a laminar flow element for flow measurement instead of an orifice plate?

There was some discussion on these on the old forum. They have their advantages but need to be in a very clean environment. My understanding is they lose their accuracy in a dirty environment. Also the ones I have seen are pretty expensive. My goal was to keep this as cheap as possible.

John

davidbraley wrote:Have any of you tried building a bench with a laminar flow element for flow measurement instead of an orifice plate?

Yes, it is a work in progress

Hi David. Are you talking about a hot wire sensor or grid from automotive induction systems? My flobench uses a hot wire for mass flow sensing. Tell me what you think. Jim

Eagle Eye,

I can tell you I tried the hot wire / film MAF sensor from a Ford I had calibration information for and found it was simply not accurate at low flow rates. When I say low flow rates anything under 100 CFM. I was using a 16 bit A to D and the output from the sensor was just not up to the task. An engineer friend pointed out that at these low flow rates the Ford my MAF was from was in closed loop idle. I can also tell you that the rather large Ford MAF was also a heck of a pressure drop as apposed to my Flow Performance flow element I am using now. If I was to start again I think I would use Bruce's design and electronics and be done with it. I will say I am happy with the Flow Performance hardware it works well.

Stay tuned,

PFM

Hi PFM. Sorry, just saw your post. Rick (60FL) thinks my hot sensor is not an automotive app. It works very well if the conditions are right. If you've read any of my other postings you'll know what I am talking about. Is the system you're using one of John's units? I think it is a sensor sticking into a piece of PVC pipe? Basically I think it works like Bruces unit. Good luck,Jim