what do you Guys think of the Blower/Motors on this site
as useful to build a FlowBench ?
FlowBench Blower/Motor
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by maxracesoftware » Wed Dec 06, 2006 5:25 pm
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by Tony » Thu Dec 07, 2006 6:33 pm
Just discovered this thread.
A brand spanking new commercial high pressure air blower would certainly be rather nice. At least you can select something suitable from the listed engineering specifications. But the cost of something new may be rather intimidating, at least for many of us.
But I still feel this is a vastly better approach than a whole bunch of noisy power hungry vacuum cleaner motors that all have horrible flow/pressure characteristics.
Another way is to study these pictures, the dimensions, and the specifications, and get a fairly good idea of what these blowers can do. Then go on a machinery junk yard scrounging expedition.
Very occasionally something like this turns up on e-bay, and there probably is not a great demand for them, except from crazy people like us.
Once you realise how crude and simple these blowers really are, you may even be tempted to build one completely from scratch. That is quite feasible, and if anyone shows interest in attempting this, I can go into some more details about how to go about it.
A brand spanking new commercial high pressure air blower would certainly be rather nice. At least you can select something suitable from the listed engineering specifications. But the cost of something new may be rather intimidating, at least for many of us.
But I still feel this is a vastly better approach than a whole bunch of noisy power hungry vacuum cleaner motors that all have horrible flow/pressure characteristics.
Another way is to study these pictures, the dimensions, and the specifications, and get a fairly good idea of what these blowers can do. Then go on a machinery junk yard scrounging expedition.
Very occasionally something like this turns up on e-bay, and there probably is not a great demand for them, except from crazy people like us.
Once you realise how crude and simple these blowers really are, you may even be tempted to build one completely from scratch. That is quite feasible, and if anyone shows interest in attempting this, I can go into some more details about how to go about it.
Also known as the infamous "Warpspeed" on some other Forums.
- Tony
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- Location: Melbourne, Australia
by Tony » Thu Dec 07, 2006 6:58 pm
Yes, varying the speed gives a wonderful control of both flow and pressure. Once it is running at a fixed speed, the pressure will remain almost constant over a very wide flow range. This is quite unlike what you get from a vacuum cleaner motor.
For any centrifugal blower:
Flow rises directly proportional to speed.
Pressure rises square law, twice the Rpm,four times the developed pressure.
Horsepower rises cubed law, twice the speed requires eight times the drive horsepower.
But you will never quite reach that extra flow, because up rating a blower will create vastly greater internal velocities and internal pressure drops. For small increases in Rpm you will come very close. But say doubling the Rpm, you might expect something like 1.8 to 1.9 times the maximum open flow.
That is what I have done. I took an original blower rated at 350 CFM and seventeen inches of water which had a 1.5Hp motor fitted to it.
I then fitted a 15Hp motor and a variable frequency drive that could run the motor from zero speed up to 120Hz. It doubled the flow, and it easily reached sixty inches of pressure. And it was silent except for air roar.
For any centrifugal blower:
Flow rises directly proportional to speed.
Pressure rises square law, twice the Rpm,four times the developed pressure.
Horsepower rises cubed law, twice the speed requires eight times the drive horsepower.
But you will never quite reach that extra flow, because up rating a blower will create vastly greater internal velocities and internal pressure drops. For small increases in Rpm you will come very close. But say doubling the Rpm, you might expect something like 1.8 to 1.9 times the maximum open flow.
That is what I have done. I took an original blower rated at 350 CFM and seventeen inches of water which had a 1.5Hp motor fitted to it.
I then fitted a 15Hp motor and a variable frequency drive that could run the motor from zero speed up to 120Hz. It doubled the flow, and it easily reached sixty inches of pressure. And it was silent except for air roar.
Also known as the infamous "Warpspeed" on some other Forums.
- Tony
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- Joined: Sat Dec 03, 2005 12:34 pm
- Location: Melbourne, Australia
by Tony » Thu Dec 07, 2006 11:41 pm
The speed, pressure and power all sound about right.
But I assume the 100mm is the intake eye diameter of the rotor, not the width of the actual rotor ?
Anyhow, it sounds like the basis of an excellent flow bench blower. It just requires a few more Rpm and Hp to really wake it up.
But I assume the 100mm is the intake eye diameter of the rotor, not the width of the actual rotor ?
Anyhow, it sounds like the basis of an excellent flow bench blower. It just requires a few more Rpm and Hp to really wake it up.
Also known as the infamous "Warpspeed" on some other Forums.
- Tony
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- Joined: Sat Dec 03, 2005 12:34 pm
- Location: Melbourne, Australia
by Tony » Sat Dec 23, 2006 4:10 pm
Anatolij,
From the picture, that looks like an Eaton M45 roots supercharger as used on the four cylinder Mercedes Benz.
The Mercedes application of the Eaton M45 supercharger are unique, in that the intake and discharge ports are both located on the same side. The 45 refers to the 45 cubic inches ( 747cc ) of air it displaces every revolution.
If you Google "Eaton M45", there should be plenty of information available on this particular supercharger. It is a very good supercharger, but rather small for an airflow bench.
I bought a secondhand centrifugal blower here in Australia that looks almost exactly like the one you are using. It is made by Mez Mohelnice of Czechoslovakia.
From the picture, that looks like an Eaton M45 roots supercharger as used on the four cylinder Mercedes Benz.
The Mercedes application of the Eaton M45 supercharger are unique, in that the intake and discharge ports are both located on the same side. The 45 refers to the 45 cubic inches ( 747cc ) of air it displaces every revolution.
If you Google "Eaton M45", there should be plenty of information available on this particular supercharger. It is a very good supercharger, but rather small for an airflow bench.
I bought a secondhand centrifugal blower here in Australia that looks almost exactly like the one you are using. It is made by Mez Mohelnice of Czechoslovakia.
Also known as the infamous "Warpspeed" on some other Forums.
- Tony
- Posts: 824
- Joined: Sat Dec 03, 2005 12:34 pm
- Location: Melbourne, Australia
by Thomas Vaught » Sun Dec 24, 2006 1:02 am
I posted this link sometime back.
The Vortron People are a US company located in California.
Tom V.
The Vortron People are a US company located in California.
Tom V.
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- Location: Michigan
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