student looking for recommendations to measure air flow

Hello,

I'm building a system for my professor and for controls I will be using a PLC from automationdirect as a way of getting into the field and learning (everything I'm doing can be done with a raspberry pi or an arduino... but we have funding and this can be used for a lot more later in the project).

Anyway, I have a few circular ducts - 3, 4, and 6 inches in diameter where I need to control airflow. The damper system I already have worked out (well - a good enough solution for now), but I'm trying to find sensors to measure air flow in the circular ducts. I'd prefer something that comes assembled in a small section of duct that I can just put in place between the existing duct which is put together using quick disconnect and toggle clamps. Air flow is 1200-2000 fpm around 80 degrees. Accuracy within 3% is acceptable.

I've found plenty on just the probes, but I'm really hoping to have something already assembled that I can just clamp on. If a prebuilt option isn't available, any recommendations on how to setup 2 probes in a circular duct?

Thanks!

not sure what your budget is, but Dwyer makes some nice duct kits...


http://www.dwyer-inst.com/Product/AirQuality/FlowSensors/

How about the automotive junk yard and look for MAF sensors of different sizes. You can then look them up online and get you wiring and scaling to connect to an analog input.

Dwyer Digihelic with analog output

https://www.instrumart.com/products/40998/dwyer-dh3-digihelic-differential-pressure-controller

These sensors use pneumatic tubing to connect to the ducts. The can measure pressure against atmospheric, or pressure differential between two points and give you an analog input scaled in pressure, or volume, or differential pressure, or velocity.

scott.lawrence said:

not sure what your budget is, but Dwyer makes some nice duct kits...


http://www.dwyer-inst.com/Product/AirQuality/FlowSensors/

Click to expand...

Thanks, I came across dwyer in my search, but wasn't sure if they made anything in the sizes I needed. The MAFS line has 4" and 6" but it looks like it's for square/rectangular ducts only, I need circular.

... actually, just realized the AFG line is trimmable, maybe I'll have to use that. Wouldn't have caught this if you didn't mention it again!

As for budget, so far I'm way under our budget for our grant, so pretty much anything [reasonable] goes.

Plastic said:

https://www.instrumart.com/products/40998/dwyer-dh3-digihelic-differential-pressure-controller

These sensors use pneumatic tubing to connect to the ducts. The can measure pressure against atmospheric, or pressure differential between two points and give you an analog input scaled in pressure, or volume, or differential pressure, or velocity.

Click to expand...

Thanks, for the actual communication between the duct and PLC I was just going to use the prosense differential sensors from automationdirect, maybe I'll use this since it has the readouts on the display as well.