Tractorsport Flowbench Forum Archive

Posted: **Thu May 14, 2009 3:51 pm**

To all,

I would like to use a single large industrial type blower in my bench. I have looked through the forum posts, but haven't found alot of discussion on this. would anyone be able to recomend a blower type, size, hp requirements to look for?

Thanks,
Kevin

Posted: **Thu May 14, 2009 4:56 pm**

For whatever reason, that doesn't seem to be a very popular configuration but there are a few people here that use a large single blower, one that comes to mind immediately is Tony. I seemed to recall that he's addressed some of the questions you've raised, try searching some of his old posts.

Posted: **Thu May 14, 2009 6:28 pm**

You are in the right place.
There is a fair bit of information in this section of the Forum, in some earlier threads. At the bottom of this page, click on "from the beginning" and a lot more earlier threads will appear.
This one has quite a bit on big blowers:

Posted: **Thu May 14, 2009 9:37 pm**

Thanks guys,

Will read the thread from the link Tony sent. I also did a quick search online and came up with this blower:

Would this be suitable?

I did a search on VFD's and so far the largest single phase input drive that I've found will run a 3 phase 3 hp motor.

Posted: **Thu May 14, 2009 9:59 pm**

Posted: **Fri May 15, 2009 3:20 pm**

Tony,

How much pressure do I need to look for total? I am building a bench from Bruce's plans and using a PTS DM.

Posted: **Fri May 15, 2009 6:52 pm**

If you plan to do your testing at 28 inches of depression, and use Bruce's recommended 16 inches drop across the measurement orifice, then the blower would need to develop an absolute minimum pressure of 28 + 16 = 44 inches at the required full required flow.

That is fairly high, but not unreasonably so.
Something specified around 50 inches at the required flow would be nice.
At around that pressure, you might need very roughly 1.5Hp for every 100 CFM to drive the blower.

Just to give you some idea what to be looking for to develop 50 inches of pressure, rotor tip speed is always the clue to pressure:

4,900 rpm with an 18 inch diameter rotor (2 pole motor, direct coupled with 120 Hz from a VFD)
3,400 rpm with a 26 inch rotor (2 pole motor, direct coupled 60Hz)
2,850 rpm with a 31 inch rotor (2, pole motor, direct coupled 50 Hz)

These dimensions are for the actual rotor, not the outer casing of the blower. You can usually get a measuring tape in through the blower inlet fairly easily, hook it over the outside of the wheel, and measure the radius. And you will be able to read the motor rpm off the rating plate on the motor.

Just realise that pressure developed is proportional to rotor tip speed SQUARED. So an inch more, or an inch less, in rotor diameter can make a fairly dramatic difference to the developed pressure.

The outer casing of the "pressure blower" you will be looking for will be huge in diameter but very skinny in width. It will have more the overall proportions of a biscuit, than a barrel.

Posted: **Mon May 18, 2009 12:44 am**

Thanks Tony,

I might be better off using vac motors for now. Will be interesting to see how Bruce's blower turns out though.

Kevin

Tractorsport Flowbench Forum Archive

Single large blower