Air Flow Measurement

A small turbine flow meter.

There are a number of possible options, some cheap and some exspensive. What we or at least I could use is a little information such as what is the pressure at delivery, what size of pipe is being used, what is the Max instantaneous usage (ball park would fine) and finally what is the top dollar amout are you willing to spend. I want to give the best possible advice so the more information you can give the better I can do, same holds true for others that may respond.

One shooting from the hip suggestion: If you pressure is 120psi or less and your max instant usage is less the 20cfm and your piping diameter is or can be sized down to 1 inch or less, you could try using a simple roto-meter for air and take readings every ten minutes for a day or two then do a little averaging math work.

Well, first of all thanks to everyone for the responses. I actually need to test 3 different machines. We run them at 70 psi, max of 75, and they have 3/8" and 1/2" air lines. The max instantaneous usage is 80 scfm but we may need to be able to go up to 100 scfm. My budget is less than $1000.

I would like to get something that I can plug into our air line and get an average rate of usage. I'm sure there are cheaper ways of doing this but I would like to remove variables and measure it directly instead of estimating it.

One option Ryan Herco

or a digital option http://www.omega.com/ppt/pptsc.asp?ref=FLR-D&Nav=greb06.

There are various options. I am currently working on an overview which I can e-mail you. I will also post it on CR4 when it is ready.

You can send me a message if you are interesed.

See also:

http://cr4.globalspec.com/comment/41730

Most Machines list CFM usage on them if not available individual devices installed on the can be used and added together. A cylinder has a volume count the strokes in normal usage per minute to come up with CFM. Air motors will have a CFM listing on name plate if not check with motor manufacturer. When you are considering a compressor best to over size and spend the extra on variable speed drive. With variable speed drive you will only consume the electrical energy necessary to maintain sufficient air for the equipment you have running. If you over size then you will have sufficient capacity for future equipment additions to your plant.

Type plates are providing just a part of the picture.

The air consumption should be measured over a period of time. This can be done by connecting the flowmeter to a PC via RS232.

A peak of ... CFM does not mean your compressor needs to have this capacity. You should analyze the length of the peaks and the duty cycles. Depending on length and height of the peak and the duty cycle, you can consider to interconnect an air buffer to create enough capacity to overcome the peak with a smaller compressor.

To use a flow meter to find the peak CFM usage will need to be done over some time.

In manufacturing you can assume you will not be running every piece of equipment at once. Until you do or have to then your system fails to provide the necessary output. Lost production cost could out way the cost of the new compressor.

All the current suggestions are based on flow meter measurements integrated over time.

This assumes you have an air supply already - and if so - can you isolate all other machines so that the compressor only has to run your machine.

That being the case (if you can) take a kW-hr power reading your compressor. Or with a stop watch note how long the compressor runs on load and off load. That will tell you how much air has been supplied over the period. But note that your compressor must be capable of supplying the max air flow demanded by your machine.

If intermittent, then a local receiver might do, but in the long term you might be better off with a bigger compressor to match the peak flow and then arranging the load control to cope with variations.

There is yet another way - using a clamp on compressed air flow meter. These would only be feasible if you wish to hire due to the high capital costs associated with purchase.

Regards..

M

Festo Corp has a nice digital flow meter with outputs, their MSF6 family. You can find info online at www.festo.com

Regard