making sense of blower specs

[streetpirate]

http://www.ametekfsm.com/Product_View.aspx?MT=1&Model_No=116378&Record_ID=6808

how do I calculate how many to use on a bench using these specs?

[streetpirate]

how does the number of blowers effect the cfm and depression I can pull through a fixed orifice size?

[86rocco1]

Okay, let's says you're building an orifice bench like Bruce's, it has up to a 16" pressure difference across the orifice and let's also say you'd like to be able to test at a 28" depression, that would mean that your vacuum motors would need to be able to produce 16+28= 44" of vacuum. Now, look at the specs from that link you gave, go down the Vacuum column until you reach a number that's bigger than 44 and you see that the chart has an entry that reads 49.3", now reading that row horizontally, we see that at 49.3" the blower can move 22 cfm of air. If you want to test parts that flowed 100 cfm @ 28", your bench would need 4 to 5 of these motors, running in parallel.


BTW, that particular motor is rather inefficient. Here's the spec chart for the blowers that Superflow uses in there high dollar benches the
, I recall reading somewhere around here that the Superflow 600 cfm bench uses 8 of these motors.

[streetpirate]

Thanks, thats exactly what I was looking for. I figured those motors were not the greatest but they were $40 shipped. It sucks that Surplus Center ran out of blowers a couple weeks before I was ready to start my build.

[86rocco1]

The 115923 is available from for $116.90. There are about a dozen places in my local area that sell vacuum cleaner parts, a couple years ago, I called several of them and found one that could get me '923 motors for about $90 Cdn each, that included a modest price break because I ordered 4 at the same time and paid up front. BTW, there seems to be a wide price range for these things, I got quoted prices as high as $189.00 per motor.

[jfholm]

I bought Domel motors from Lighthouse. The motor I bought is the 49637202 and was $99.95 and that includes the shipping.

At 47.6" H2O they flow 110.5 cfm and the warranty is double what they give on the Ametek. That is what sold me on the Domels.

John

[streetpirate]

The Ametek 122093-00 from central vacuum looks to be the best bang for the buck, 91cfm at 51", $540 for 6, the Domels listed above 110cfm @ 47" $630 for 6. (only found them for $105 each and I dont think it included shipping.)

[86rocco1]

Don't order on-line, find a phone number, call and talk to a real live person preferably someone in a position of authority, since you're planning to buy 6, things like shipping or even price may be somewhat negotiable.