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Posted: Mon Nov 26, 2007 1:18 pm
by smartmonkey
12 to 14 cfm (3HP or 2.2KW) compressors are about £350 new. I have a few air tools (twenty or so) but I only bother using the specialist ones on a regular basis. The problem is they are so wasteful - you are using a 3HP compressor to drive a .25HP tool.

On the assembly line they pressure fill cars within 30 seconds. They have thousands of litres of coolant mixed up and just pump it through the system. Sadly you cant reproduce this at home.

Posted: Mon Nov 26, 2007 2:30 pm
by mikeonb4c
smartmonkey wrote:The problem is they are so wasteful - you are using a 3HP compressor to drive a .25HP tool.
But are they though SM? I'd imagined the the 3HP was what was needed to push air into the reservoir in order to achieve a certain pressure. How efficiently and how energetically the stored energy is released/used is a function of tool design ( :shock: ) and I could see pneumatic being quite an efficient option of some applications, though not being an engineer I couldn't say with authority. :roll:

Posted: Tue Nov 27, 2007 10:04 am
by tonygadget
smartmonkey wrote:12 to 14 cfm (3HP or 2.2KW) They have thousands of litres of coolant mixed up and just pump it through the system.
SM, do you think that using pressure to pump coolant via the header tank, (like auto brake bleeders) collecting excess via the bleeder hose & perhaps repeating until satisfied would replicate the production line without recourse to vacuums?

Posted: Tue Nov 27, 2007 1:50 pm
by smartmonkey
I dont think you could guarantee a result so I would stick with the tried and tested methods.

Posted: Tue Nov 27, 2007 2:05 pm
by smartmonkey
mikeonb4c wrote:
smartmonkey wrote:The problem is they are so wasteful - you are using a 3HP compressor to drive a .25HP tool.
But are they though SM? I'd imagined the the 3HP was what was needed to push air into the reservoir in order to achieve a certain pressure. How efficiently and how energetically the stored energy is released/used is a function of tool design ( :shock: ) and I could see pneumatic being quite an efficient option of some applications, though not being an engineer I couldn't say with authority. :roll:
Yes they really are awfully inneficient devices. An electric motor is driving an air pump which is driving an air pump which is driving the tool. Air pumps themselves are desperately poor devices because of mechanical and heat energy losses. I was running one of my air drills the other day (it was the only drill that would fit) and the comp was running about 50% of the time. That is a 1.5 HP drill doing less well than a 0.5HP electric drill would. I only have so many air tools because I am mentally unwell and have an uncontrollable urge to purchase shiny things. A good air tool is also more expensive than a good electric equivalent.

Some air tools are essential though, for example:
Joddlers
Punches
Spray guns
Blow guns
Nibblers
Shears
Body saws
DA sanders
Long bed sanders
Impact wrenches
Needle scalers
Hammers

All of which have no suitable electric replacement.

Posted: Wed Nov 28, 2007 10:27 am
by tonygadget
Keep SM away from MachineMart / NorthernTools! :twisted:

ps. snap :D

Posted: Wed Nov 28, 2007 2:48 pm
by mikeonb4c
Got your message SM - I'll get back in me box :lol: :lol: