- Thread starter NTwoO
- Start date
Yep, they're very quiet, but they usually don't produce much air flow. And you'll need to convert power from 240V to 12V.
You can also get rack-mounted fans in different configurations, from trays (up to down or vice versa) or panel (horizontal flow). Like these:
http://www.rackmountsolutions.net/Rackmount_Fans_Filters.asp
but then you're spending money.
(Disclaimer: I'm not recommending that website, it was just an example that was top of my Google search).
Good luck!
You can also get rack-mounted fans in different configurations, from trays (up to down or vice versa) or panel (horizontal flow). Like these:
http://www.rackmountsolutions.net/Rackmount_Fans_Filters.asp
but then you're spending money.
(Disclaimer: I'm not recommending that website, it was just an example that was top of my Google search).
Good luck!
NTwoO
More skill with grinder than welder
- Messages
- 489
These 110V versions are also an option. Sites like farnell, RS and conrad also offer 230V versions at a slightly higher price. The 12V versions can run off an old laptop or other switch mode supply. A regulator with temp control can be added on a later stage (or find an existing regulator for a few euro's) The fan I posted does 97m3/h that is quite some flow if one does 3 of them. Calculated back to cf/min one looks at about 150 per fan, not bad. Thanks for wishing me luck . Of course I am also pushing for a sensible design
. Of course I am also pushing for a sensible designI once built a computer cabinet. That is I bought a normal cabinet, which I insulated and then I got some fans for it and so forth. I completely hid my computer into it, it was quiet and it kept the computer fairly cool.
In hindsight it was a much more complex problem than I thought. I didn't move enough air at all. Hence the "good luck".
If you want to have the compressor "on" all day. I.e compressed air on tap at any time, controlling the fans by thermostat is much more important. If you are only using the compressed air supply "at some particular time", then you can have the fans running when the electricity is connected to the fan.
IMvHO obviously. 
In hindsight it was a much more complex problem than I thought. I didn't move enough air at all. Hence the "good luck".
If you want to have the compressor "on" all day. I.e compressed air on tap at any time, controlling the fans by thermostat is much more important. If you are only using the compressed air supply "at some particular time", then you can have the fans running when the electricity is connected to the fan.
IMvHO obviously.
NTwoO
More skill with grinder than welder
- Messages
- 489
Oh, All in absolute good humour! Thanks for the tips. Such experience shows in your comments and assessment of my design. It wasn't interpreted in a negative way at all. Your tip of the speed control is on the button with my thoughts. Not all to complex is perfect for this design. I'll go for switch mode supply, though. There are enough of them lying around. Another option is using the fans with 3 different speed settings and just doing some emperical checks with the NTC. Ducting the fans might also help to prevent circulation around the fans and force them to suck from the intake.I'll maybe put a plug in the box. Those are lying around spare. Furthermore I might make some baffles with PU foam in a plastic bag around the shroud. Oh, and my calculations for cft conversion was the dogs bottom. Ignore my useless attempts at doing Imperial units.
Last edited:
Don't worry, I'm not "imperial", nor did I take the "Thanks for wishing me good luck" in any bad way. I did however think it was apropriate to shed a bit of light on my struggles.
There's tons of places where I could imagine using fans and a temperature controller, that's just the way my brain works.
Many of those desk fans can be purchased for under £20, and they usually have three speeds and time delay (i.e turn off in 30, 60 or 120 minutes). Bang for the buck ratio I think that'll be hard to beat.
Oh, and another thing I have often considered doing is a passive heat sink. I.e Big aluminium fins, inside and out. In a box like this, you could buy two big heat-sinks (fins), and then a thick billet-alu piece the thickness of the plywood you've used. Cut a hole, mount the alu flush to the plywood. Then screw in the heat-sinks on both sides. A passive heat sink like that. Say some 100mm by 300mm would get rid of a lot of heat.
Anyway. I might be giving you solutions to problems that don't exist, or solutions that have already been discarded for some reason.
I'm very intrigued into what direction your decisions take you!
There's tons of places where I could imagine using fans and a temperature controller, that's just the way my brain works.
Many of those desk fans can be purchased for under £20, and they usually have three speeds and time delay (i.e turn off in 30, 60 or 120 minutes). Bang for the buck ratio I think that'll be hard to beat.
Oh, and another thing I have often considered doing is a passive heat sink. I.e Big aluminium fins, inside and out. In a box like this, you could buy two big heat-sinks (fins), and then a thick billet-alu piece the thickness of the plywood you've used. Cut a hole, mount the alu flush to the plywood. Then screw in the heat-sinks on both sides. A passive heat sink like that. Say some 100mm by 300mm would get rid of a lot of heat.
Anyway. I might be giving you solutions to problems that don't exist, or solutions that have already been discarded for some reason.
I'm very intrigued into what direction your decisions take you!
NTwoO
More skill with grinder than welder
- Messages
- 489
I went for the pc fans with 140m3/h flow. Three are sitting at the bottom of the box. They have rheostats for controlling the fan speed, but are on full blast at this stage. There is a plug added to the box with a 5m 2.5mm2 core wire. I ran a quick test of the current setup.
before startup: 21.8 degC
1min after startup. 23.3
1min 20 sec the compressor stopped 23.8
2 min 23.1
3 min.23.3
The gaskets on the edge of the box are not in place yet and the clips for the bottom hinged part is not present. I squeezed the bottom part as tight as possible with my calf, but it still leaked quite a bit. That would surely improve the performance.
When I let my calf go, the temp went up to 24.3 degrees, so the leakage is noticeable. Foto's to follow.
before startup: 21.8 degC
1min after startup. 23.3
1min 20 sec the compressor stopped 23.8
2 min 23.1
3 min.23.3
The gaskets on the edge of the box are not in place yet and the clips for the bottom hinged part is not present. I squeezed the bottom part as tight as possible with my calf, but it still leaked quite a bit. That would surely improve the performance.
When I let my calf go, the temp went up to 24.3 degrees, so the leakage is noticeable. Foto's to follow.
NTwoO
More skill with grinder than welder
- Messages
- 489
OK, a pic of the fan setup:
Thin wire runs to the NTC at the intake. Intake airflow is not ideal, but good enough.
Current figures with gasket in place for the door.
Start 21.001
1min 22.626
2min 24.048
stop at 2m45 25.396
3m 23.145
4m 22.456
on at 4m30s 22.288
5m 25.801
6m 26.642
off at 6m30 27.077
7m 23.145
Thin wire runs to the NTC at the intake. Intake airflow is not ideal, but good enough.
Current figures with gasket in place for the door.
Start 21.001
1min 22.626
2min 24.048
stop at 2m45 25.396
3m 23.145
4m 22.456
on at 4m30s 22.288
5m 25.801
6m 26.642
off at 6m30 27.077
7m 23.145
i make and sell similar item.
Hi
Just my input!
I manufacture items for noise control and acoustics, i make quite often a 'shoebox' which is a compressor in an acoustic lined box, air inlet and forced air outlet is essential! in other words you do not blow cold air over the compressor to cool it, you have an extract aperature with a fan to 'drag' the air out, usually at a hot area around where the motor is situated. The type of fans in your pics are simialr to what i use, a 240v version with low noise bearings.
A hot compressor wont live long.
i would post a picture but dont know how to!!!
Dave
Hi
Just my input!
I manufacture items for noise control and acoustics, i make quite often a 'shoebox' which is a compressor in an acoustic lined box, air inlet and forced air outlet is essential! in other words you do not blow cold air over the compressor to cool it, you have an extract aperature with a fan to 'drag' the air out, usually at a hot area around where the motor is situated. The type of fans in your pics are simialr to what i use, a 240v version with low noise bearings.
A hot compressor wont live long.
i would post a picture but dont know how to!!!
Dave
NTwoO
More skill with grinder than welder
- Messages
- 489
Ooooh, This sound interesting!! Could you post a photo? There are two options, use the photo album option of this site or use a site like fritter or photobucket.
When the compressor stops, the air flow is still quite strong on the exhaust. Fans pump best with cold air. That was my reason for placing it on the intake.
When the compressor stops, the air flow is still quite strong on the exhaust. Fans pump best with cold air. That was my reason for placing it on the intake.
Dave I would like to see your shoe box as well, have a look at Malcolm`s tutorial on uploading photos.
http://www.mig-welding.co.uk/forum/showthread.php?t=5016
NT why don't you measure the air entering and air leaving temps with the fans blowing and then sucking and see which one gives you the biggest temperature differential.
http://www.mig-welding.co.uk/forum/showthread.php?t=5016
NT why don't you measure the air entering and air leaving temps with the fans blowing and then sucking and see which one gives you the biggest temperature differential.
rtbcomp
Moderator
- Messages
- 18,574
- Location
- Sheffield UK
I'd add my vote to sucking air out rather than blowing it in.
If you blow air into a box you increase its pressure and therefore temperature and the heat generated by the fans adds to the heat input. Sucking air out drops the pressure and temperature and the heat from the fans goes directly to atmosphere.
Personally I wouldn't bother with temperature switched fans, just more to go wrong for little or no benefit.
Put the fans near the top where the hot air is and the inlet to the box near the bottom.
Extend the inlet to the pump to the bottom of the box or even outside the box so it doesn't suck hot air in.
If you blow air into a box you increase its pressure and therefore temperature and the heat generated by the fans adds to the heat input. Sucking air out drops the pressure and temperature and the heat from the fans goes directly to atmosphere.
Personally I wouldn't bother with temperature switched fans, just more to go wrong for little or no benefit.
Put the fans near the top where the hot air is and the inlet to the box near the bottom.
Extend the inlet to the pump to the bottom of the box or even outside the box so it doesn't suck hot air in.
