Previous in Forum: Crude Oil Fired Generators   Next in Forum: British Sniper Shoots Over a Mile
Close
Close
Close
13 comments
Guru
United Kingdom - Member - Old New Member

Join Date: Jul 2005
Location: South east U.K.
Posts: 3550
Good Answers: 93

Air Flow - Need 1/2 CFM at 5-8 PSI

05/07/2010 8:16 AM

I need to trial a piece of equipment at work but don't want to spend out much in case it is not useful. It requires an air supply of ½ CFM at 5-8 PSI but I don't have any feel for how much air that is, it doesn't seem like much air flow & I'm thinking I could use something like a hairdryer to provide it.

Originally I was going to use a bottle of nitrogen but they are in short supply here at the moment. We have no compressors available.

The kit is a hobby type powder coat gun & the air is to fluidise and deliver the powder.

__________________
I didn't have a really important life, but at least it's been funny (Lemmy Kilminster 1945-2015)
Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Guru

Join Date: May 2007
Location: Ohio. USA
Posts: 574
Good Answers: 30
#1

Re: Air flow

05/07/2010 8:33 AM

Sorry, something like a hair dryer will not develop even a few PSI.

On the positive side, that low of a compressed air requirement can be provided by even the smallest portable compressor. The portable single phase units that plug into house current will do it. I quickly checked and even some 12 Volt units that plug into your car can do it.

You may be able to charge up a portable tank and carry it to point of use depending on how long you need to operate.

__________________
Whatever you are, be a good one. Abraham Lincoln
Register to Reply
Guru
United Kingdom - Member - New Member Hobbies - Musician - New Member Engineering Fields - Mechanical Engineering - New Member Hobbies - Target Shooting - New Member Engineering Fields - Power Engineering - New Member Hobbies - Fishing - New Member

Join Date: Mar 2007
Location: South-east corner of Spain 50 48 49.24N 2 28 27.70W
Posts: 1508
Good Answers: 31
#2

Re: Air flow

05/07/2010 8:39 AM

How about using the spare tyre of the car! I know a bloke who used a spare tyre for air brush work! Put a cheap regulator on the valve and off you go! Or if that isn't enough quantity of air, use a vacuum cleaner in reverse, better than messing up the wife's hair drier!

__________________
“It's kind of fun to do the impossible.” Walt Disney
Register to Reply
Guru
United Kingdom - Member - Old New Member

Join Date: Jul 2005
Location: South east U.K.
Posts: 3550
Good Answers: 93
#3

Re: Air flow

05/07/2010 9:06 AM

Shame about the hair dryer, I thought that taking the large area air flow from the dryer into a small delivery pipe would give me some pressure.

Good thoughts about using a tyre inflater, I've got a jump starter with a compressor built in that I could have a play with over the weekend. Maybe with a reservoir that could do it.

The ½ CFM sounds like just a gentle breeze, is that right?

__________________
I didn't have a really important life, but at least it's been funny (Lemmy Kilminster 1945-2015)
Register to Reply
Guru

Join Date: May 2007
Location: Ohio. USA
Posts: 574
Good Answers: 30
#4
In reply to #3

Re: Air flow

05/07/2010 9:48 AM

Just a little more information about using a hair dryer.

It is common for commercial centrifugal air movers to operate in the 1 to 3 inches of water range. Three inches of water is .11 psi. I suspect this or less is where a hair dryer would be. Higher pressure commercial air movers would be in the 15 inches of water and up. That is equal to .4 psi. I have a regular centrifugal fan continuously operating at 20 inches of water (.72 psi). Of coarse there are centrifugal air movers designed to operate at much higher pressure (a turbocharger for example) but they are the exception.

__________________
Whatever you are, be a good one. Abraham Lincoln
Register to Reply
Guru
Hobbies - DIY Welding - Don't Know What Made The Old Title Attractive... Popular Science - Weaponology - New Member United States - US - Statue of Liberty - 60 Year Member

Join Date: Apr 2009
Location: Yellowstone Valley, in Big Sky Country
Posts: 6962
Good Answers: 283
#5

Re: Air Flow - Need 1/2 CFM at 5-8 PSI

05/07/2010 11:21 AM

How about an air pump for a hobby aquarium?

While the internet is full of places to order, tech data is pretty scarce. But offhand, I would guess outflow and pressure are somewhere around your requested numbers.

__________________
When you come to a fork in the road, take it. (Yogiism)
Register to Reply
Guru
Engineering Fields - Electrical Engineering - Analog and Digital Circuit Design Engineering Fields - Electromechanical Engineering - Transformers, Motors & Drives, EM Launchers Engineering Fields - Engineering Physics - Applied Electrical, Optical, and Mechanical

Join Date: Jan 2008
Location: NY
Posts: 1208
Good Answers: 119
#6

Re: Air Flow - Need 1/2 CFM at 5-8 PSI

05/07/2010 1:37 PM

Suggest something similar to one of these low end compressors.

http://www.safety-devices.com/12-volt-air-compressor.htm

Shop around and you might be able to find some at about 1/2 the cost of the ones listed above. Hobby air brush compressors are also an option.

Register to Reply
Guru

Join Date: Apr 2006
Location: Cincinnati, Ohio, USA
Posts: 662
Good Answers: 48
#7

Re: Air Flow - Need 1/2 CFM at 5-8 PSI

05/08/2010 1:04 AM

Just so you know "how much" 1/2 CFM is-

If you build a compressor with a 1.00 inch diameter cylinder that is 4.00 inches long and the piston has a 2.00 inch stroke running at 550 RPM, you will produce 0.500 CFM of air at 7.35 PSIG- a 5.00 inch long cylinder will yield 5.88 PSIG discharge.

Most of the devices discussed, including the fish tank pump, will likely not produce the 5-8 PSIG that you require. They are designed to operate under about 2 feet of water- or less than 1 PSIG static pressure. Even a 0.5 PSIG loss through an air stone will not be even close.

__________________
NO MATTER HOW WELL YOU HAVE DONE SO FAR, ALWAYS TRY TO BE BETTER TOMORROW.
Register to Reply
Guru

Join Date: Jun 2009
Location: Bangalore, India
Posts: 725
Good Answers: 23
#8

Re: Air Flow - Need 1/2 CFM at 5-8 PSI

05/08/2010 1:42 AM

A human being breathes out 1/4 cfm at rest.

An aquarium pump is a kind of diaphragm compressor. Versions to suit your capacity are available.

bioramani

__________________
bioramani
Register to Reply
Anonymous Poster
#9

Re: Air Flow - Need 1/2 CFM at 5-8 PSI

05/09/2010 11:28 PM

Search for Thomas Diaphragm Pumps.I had to have a small compressor for a bubble tube controller, at 20 feet of water pressure. Reasonably priced, quiet, durable,and easy to repair if needed.

Register to Reply
Guru
United Kingdom - Member - Old New Member

Join Date: Jul 2005
Location: South east U.K.
Posts: 3550
Good Answers: 93
#10

Re: Air Flow - Need 1/2 CFM at 5-8 PSI

05/12/2010 4:43 AM

I never did get to play with the tyre inflater, instead I spent the weekend finding & fixing a water leak in my kitchen.

I've managed to try out the equipment by borrowing a bottle of nitrogen gas which worked OK.

Thanks for all the suggestions.

__________________
I didn't have a really important life, but at least it's been funny (Lemmy Kilminster 1945-2015)
Register to Reply
Guru
United Kingdom - Member - New Member Hobbies - Musician - New Member Engineering Fields - Mechanical Engineering - New Member Hobbies - Target Shooting - New Member Engineering Fields - Power Engineering - New Member Hobbies - Fishing - New Member

Join Date: Mar 2007
Location: South-east corner of Spain 50 48 49.24N 2 28 27.70W
Posts: 1508
Good Answers: 31
#11
In reply to #10

Re: Air Flow - Need 1/2 CFM at 5-8 PSI

05/12/2010 8:35 AM

So the missisus hair drier got away unscathed!!

__________________
“It's kind of fun to do the impossible.” Walt Disney
Register to Reply
Guru
United Kingdom - Member - Old New Member

Join Date: Jul 2005
Location: South east U.K.
Posts: 3550
Good Answers: 93
#12

Re: Air Flow - Need 1/2 CFM at 5-8 PSI

05/24/2010 4:37 AM

I got lucky yesterday at the local boot sale & picked up a small electric compressor for £7. 116psi max with 7cfm & a 6 litre tank. It works fine although I had to drain a lot of crap from the tank.

__________________
I didn't have a really important life, but at least it's been funny (Lemmy Kilminster 1945-2015)
Register to Reply
Guru
United Kingdom - Member - New Member Hobbies - Musician - New Member Engineering Fields - Mechanical Engineering - New Member Hobbies - Target Shooting - New Member Engineering Fields - Power Engineering - New Member Hobbies - Fishing - New Member

Join Date: Mar 2007
Location: South-east corner of Spain 50 48 49.24N 2 28 27.70W
Posts: 1508
Good Answers: 31
#13

Re: Air Flow - Need 1/2 CFM at 5-8 PSI

05/24/2010 6:04 AM

Turned out fine again!!

__________________
“It's kind of fun to do the impossible.” Walt Disney
Register to Reply
Register to Reply 13 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Copy to Clipboard

Users who posted comments:

Anonymous Poster (1); bioramani (1); DaveB (2); Doorman (1); energygod (1); mjb1962853 (1); Mr. Truman Brain (3); Nigh (3)

Previous in Forum: Crude Oil Fired Generators   Next in Forum: British Sniper Shoots Over a Mile

Advertisement