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Testing Pressure/Airflow How?
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| I have been asked to design a electric blower unit for a childrens
bouncy castle manufactuerer. I have some of the competetions models
and litrature, which all quote performance in C.F.M (range 1 - 1500)
and Inch W.G. (range 0 - 15). I need to construct a DIY test rig to
measure my blower against their blowers. I was thinking on the lines
of a Manometer in the output tube of the blower, followed by some way
of a variable restricting valve to reduce the airflow, followed by a
wind vane anonometer in the resultant exhaust tube. Is this the way to
go? I would also like advice on suitable meters for the job. This will
most probably be a one off experiment, so cost is an issue.
Mark Scotford in Spain
mark@markXscotford.com (remove the X to reply)
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| Hi Mark
The only instrument that I know of to measure CFM
is made by Alnor Air Volume meter 5-2000 cfm apx. cost $2105.00
do not get confused between air volume and air velocity
W.G. water gauge 0-15" that you can make up you self
out of see trough tubing, make up U tube and fill with water
one side of tube goes on intake and the other on outlet.
Good luck from Dido
"Mark" <Mark@> wrote in message
news:fvi6e11s7sri6d5dcqr97igbp1npn9mfi7@4ax.com...
>I have been asked to design a electric blower unit for a childrens
> bouncy castle manufactuerer. I have some of the competetions models
> and litrature, which all quote performance in C.F.M (range 1 - 1500)
> and Inch W.G. (range 0 - 15). I need to construct a DIY test rig to
> measure my blower against their blowers. I was thinking on the lines
> of a Manometer in the output tube of the blower, followed by some way
> of a variable restricting valve to reduce the airflow, followed by a
> wind vane anonometer in the resultant exhaust tube. Is this the way to
> go? I would also like advice on suitable meters for the job. This will
> most probably be a one off experiment, so cost is an issue.
>
> Mark Scotford in Spain
> mark@markXscotford.com (remove the X to reply)
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| Hi Mark
The only instrument that I know of to measure CFM
is made by Alnor Air Volume meter 5-2000 cfm apx. cost $2105.00
do not get confused between air volume and air velocity
W.G. water gauge 0-15" that you can make up you self
out of see trough tubing, make up U tube and fill with water
one side of tube goes on intake and the other on outlet.
Good luck from Dido
"Mark" <Mark@> wrote in message
news:fvi6e11s7sri6d5dcqr97igbp1npn9mfi7@4ax.com...
>I have been asked to design a electric blower unit for a childrens
> bouncy castle manufactuerer. I have some of the competetions models
> and litrature, which all quote performance in C.F.M (range 1 - 1500)
> and Inch W.G. (range 0 - 15). I need to construct a DIY test rig to
> measure my blower against their blowers. I was thinking on the lines
> of a Manometer in the output tube of the blower, followed by some way
> of a variable restricting valve to reduce the airflow, followed by a
> wind vane anonometer in the resultant exhaust tube. Is this the way to
> go? I would also like advice on suitable meters for the job. This will
> most probably be a one off experiment, so cost is an issue.
>
> Mark Scotford in Spain
> mark@markscotford.com (remove the X to reply)
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| On Sun, 24 Jul 2005 13:30:22 GMT, "DiDo" <a.seput@verizon.net> wrote:
>Hi Mark
>The only instrument that I know of to measure CFM
>is made by Alnor Air Volume meter 5-2000 cfm apx. cost $2105.00
>do not get confused between air volume and air velocity
>W.G. water gauge 0-15" that you can make up you self
>out of see trough tubing, make up U tube and fill with water
>one side of tube goes on intake and the other on outlet.
>Good luck from Dido
Thanks for the info, is there no DIY way to get a rough reading of
C.F.M.?
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| On Sun, 24 Jul 2005 13:30:22 GMT, "DiDo" <a.seput@verizon.net> wrote:
>Hi Mark
>The only instrument that I know of to measure CFM
>is made by Alnor Air Volume meter 5-2000 cfm apx. cost $2105.00
>do not get confused between air volume and air velocity
>W.G. water gauge 0-15" that you can make up you self
>out of see trough tubing, make up U tube and fill with water
>one side of tube goes on intake and the other on outlet.
>Good luck from Dido
Would an air volume meter from a car do it?
http://cgi.ebay.co.uk/ws/eBayISAPI....ssPageName=WDVW
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| I will be honest and say I do not know
Dido
"Mark" <Mark@> wrote in message
news:mb67e1lv3peaed7ttp5af4o1jj8ls2cqpi@4ax.com...
> On Sun, 24 Jul 2005 13:30:22 GMT, "DiDo" <a.seput@verizon.net> wrote:
>
>
> Thanks for the info, is there no DIY way to get a rough reading of
> C.F.M.?
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| sixfoot7@sccoast.net 2005-07-24, 9:14 pm |
| David,
Good ideas except the damper shown is too light to handle more than 1/2
inch WG.
Mark,
Get a heavier damper such as a Blast Gate from Kirk & Blum.
Measure the velocity pressure in the center of the duct, then multiply
that times .9 because the average velocity pressure would be lower.
Then multiply the square root of the velocity pressure (In inches WG)
times 4005. That is the velocity in Feet per minute. Multiply that
times the area of the duct (In Square Feet) and you will have CFM.
The measuring point should be 10 duct diameters from any duct fitting
or open end or blower discharge for best accuracy. It is better to be
even further from the blower discharge if possible.
Hope this helps
Stretch
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| TAB Dude 2005-07-25, 10:21 am |
| For a DIY method attach a length of straight duct to your fan. Get a
digital manometer with a Pitot Tube and do a traverse of the duct 10 duct
diameters from the fan. Manometer with Pitol tube (or a hotwire anomometer)
from Alnor will run about $600.00. You cannot do this type of testing
without a meter.
TAB Dude
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| Vicki Szaszvari 2005-07-26, 12:21 am |
| You have never heard of a Flow Hood, made in Scottsdale, AZ? That's
what everyone around here uses.
DiDo wrote:
> Hi Mark
> The only instrument that I know of to measure CFM
> is made by Alnor Air Volume meter 5-2000 cfm apx. cost $2105.00
> do not get confused between air volume and air velocity
> W.G. water gauge 0-15" that you can make up you self
> out of see trough tubing, make up U tube and fill with water
> one side of tube goes on intake and the other on outlet.
> Good luck from Dido
>
> "Mark" <Mark@> wrote in message
> news:fvi6e11s7sri6d5dcqr97igbp1npn9mfi7@4ax.com...
>
>
>
>
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