Air reservoir design

Submitted: Monday, May 19, 2003 at 00:02
ThreadID: 4984 Views:4342 Replies:8 FollowUps:10
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Does anybody know how to build an air reservoir to use in series with a compressor for blowing up tyres.

Things I would be interested in would be:

* What size should it be (in litres I would like it to hold enough air to blow up 2 tyres from 20 to 40 psia?)
* Where can I get a cylinder?
* How do I stop the air coming out? I presume I need a some sort of air gun trigger at the tyre inflation end? What can I use?

My ARB compressor has a 100 psi cut-off so the cylinder should at least be rated to this?

What I would do is pump up the air reservoir as I approach an area where I need to blow up my tyres so that I am ready to go. This should compliment my compressor and make inflation faster.

Any suggestions or designs gratefully received - note that due to public liability I will assume that you are not offering me advice but are informing me of your own experiences, from which I can draw my own conclusions!!! Bloody lawyers ruined our way of life.

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Reply By: Dozer - Monday, May 19, 2003 at 08:27

Monday, May 19, 2003 at 08:27
I am using a old dry powder fire extinguisher as a pressure vessel, it is rated to 150psi std
AnswerID: 20399

Reply By: Tuco69 - Monday, May 19, 2003 at 08:44

Monday, May 19, 2003 at 08:44
Go to truck/bus wreckers and get as big an air tank as you can fit in where you plan to mount it. Put a "T" connection on your compressor and run one side with 12mm air hose to the tank. The other side of the "T" is to your existing ARB tyre inflation line. Make sure that the lines and also the "T" are at least 12mm. Smaller lines will restrict the flow rate.
Truck/bus air tanks are also usually fitted with a drain valve so that you can dump water from the condensation that accumulates in the system. No matter what compressor you use, water from condensation will always be present in the system from the heat that is generated in compressing the air. You need to be able to remove this water or it ends up in your tyres and will damage any air tools that you use once you have an accumulator tank.

Tuco in Cairns
AnswerID: 20400

Reply By: Member - Martyn (WA) - Monday, May 19, 2003 at 09:01

Monday, May 19, 2003 at 09:01
I was looking to do this, I mounted an old breathing air cylinder on my GQ more or less under the rear passenger seat, put a relief valve on the T peice just because it was the right thing to do, also fitted a small valve to drain off the condensation. I bought the ARB compressor and advised them of my intentions, and they told me that doing this would do more harm than good to the compressor, there was also questions about the validity of the warranty using the compressor this way. The extra heat generated by the compressor to maintain the cylinder at lets say 100 psi would be considerable.
I think plumbing up a air con compressor may be a better option I'm not sure about this I haven't done it and I'm not sure how the air con compressor would go.
Keep the shiny side up
AnswerID: 20401

Follow Up By: Member - Rohan K - Monday, May 19, 2003 at 12:20

Monday, May 19, 2003 at 12:20
Martyn, I read a story a while ago about a fellow who built a tank - used 4" gal pipe (from memory) that run along the back of his truck inside the chasis cross member (again, from memory). He fitted some sort of one-way pressure valve on the inlet side so there was no back-pressure on the compressor or lines. I don't remember how he controlled the pressure in the tank or the on/off control of the compressor, but there must be a fairly simple solution to that, too.

Be good, or be quick.
Rohan (Sydney)
FollowupID: 13087

Follow Up By: Busta - Monday, May 19, 2003 at 13:43

Monday, May 19, 2003 at 13:43

I wouldn’t pay too much attention to whomever you spoke to at ARB. Given that the ARB compressor comes with a pressure vessel which does exactly what your system does, but on a smaller scale, I fail to see how this would cause any damage. 100psi is 100psi regardless of the volume of air. I'm about to do exactly the same thing with my ARB compressor and the only thing that worries my is leaving it pressurised all the time. I plan on switching it on shortly before I need to reinflate my tyres and draining the tank afterwards. Isn’t great to see salespeople who know their product and can give quality advice?
FollowupID: 13090

Follow Up By: Member - Martyn (WA) - Monday, May 19, 2003 at 15:51

Monday, May 19, 2003 at 15:51
One of the guys in the club I belong to has plumbed up his tubing in the bullbar as an air reciever, seemed like a pretty novel idea to me and it works which is the important bit, in the evnt of an accident could prove interesting, adds a new meaning to the air bag concept.
In reply to the comment from Busta, the sales guy at ARB in the past has given good advice and when he was talking about how much extra work the compressor had to do to pump the cylinder back up to 100 psi after being let down to what ever the tyre pressure was initially being maybe 20 psi seemed to make some sense, he had nothing to gain by telling me any different, you will have to let me know how you go with your set up. As you correctly say 100 psi is 100 psi the stored energy you have to replace is the tricky bit. Keep the shiny side up
FollowupID: 13094

Follow Up By: Member - AndrewPatrol - Monday, May 19, 2003 at 18:43

Monday, May 19, 2003 at 18:43
I'd suggest that they are concerned about the run time as well as the back pressure, as the compressor is only rated to run for a certain time and pumping a vessel to a 100 psi over and over will take forever. Imagine pumping your tyre to 100, it takes long enough getting it to 40.
FollowupID: 13099

Follow Up By: Dozer - Monday, May 19, 2003 at 22:15

Monday, May 19, 2003 at 22:15
Hi Guys
I ran an Arb with a fire extinguisher approx 30cm long by15cm diameter for years and as far as i know it is still going, took 80 or so seconds to fill up if i opened a valve to allow air into it. It was just joined to the arb tank with copper pipe and shutoff valve. Used it with an air horn mucjh like a trains:-)
FollowupID: 13131

Follow Up By: Member - Rohan K - Tuesday, May 20, 2003 at 11:31

Tuesday, May 20, 2003 at 11:31
Martyn, I just read (in 4x4 Australia) about a similar set-up - plumbed into the bull-bar. I wouldn't think 100 psi would be much of an issue in an accident.

There seems to be a myriad of solutions to the "problem".Be good, or be quick.
Rohan (Sydney)
FollowupID: 13169

Follow Up By: Member - Rohan K - Tuesday, May 20, 2003 at 11:34

Tuesday, May 20, 2003 at 11:34
Andrew, you're probably right, but unlike a tyre, its not essential to fill the tank in one go, at one time. If controllable from the cabin, you could even switch in on and off while driving to fill the tank without over-running the compressor.Be good, or be quick.
Rohan (Sydney)
FollowupID: 13170

Reply By: Kev - (Cairns,QLD) - Monday, May 19, 2003 at 09:31

Monday, May 19, 2003 at 09:31
Forget that public liability rubbish, Why are people so worried about having the fredom of speach ?

It seems you are more worried about a air tank than a defaming remark about lawyers.

If you can't ask questions about such things as you have asked then we all may as well log off now !!!!!!

Relax and enjoy this site.

AnswerID: 20402

Reply By: jaycee - Monday, May 19, 2003 at 19:12

Monday, May 19, 2003 at 19:12
I suggest you look at the ARB specs at how long it takes to pump a tyre up by 20 psi then times it by 5. remember that the ARB isnt rated for continuous use like some of the other bigger capacity pumps. If you want bags of air the only way to go is using an air conditioner pump belt driven of the pulley. Not too difficult to set up. Here's the basic specs.
On the inlet side to the air con pump fit a small K&N air filter and between this and the pump install an oiler (most air con pumps will need a small amount of oil for lubrication). On the outlet side run copper tube to a low gennie valve - preferably with a ball valve switch for continuous operation. Allow as much copper tube as you can to allow for heat dissapation. After the gennie valve install an oil filter catch pot with a drain back to the oiler. Next in line after the catch pot fit a pressure gauge rated to 150psi max, after this fit a 240volt (because getting a 12 or 24 volt one is nigh impossible) pressure switch to disengage the clutch on the A/C pump. The switch will need to be rated to 90 psi on and 125psi off. From here on you can run 3/8 inch 200psi high heat hose to a pressure vessel (try an old air brake tank off a truck) fit with a condensate drain (if one isnt already fitted) install a 150 psi relief valve and on the tank outlet fit some more hose an end with the usual air outlet connector. If you are a do-it-yourselfer it should cost around the same as a new ARB pump. The only problem with the newer trucks now-a-days is that there's stuff all romm to fit the additional a/c pump in the engine bay.
Good luck
AnswerID: 20449

Follow Up By: Kev - (Cairns,QLD) - Monday, May 19, 2003 at 19:55

Monday, May 19, 2003 at 19:55
Sounds exactly what i did except i don't have an oiler (drip oil in from time to time).
I was told that the oilers need air pressure to work but in our set up they are on the suction side.

For the inlet air instead of fitting a extra filter i drilled and tapped a connection to my engine air filter box.

Whats a "low gennie valve" ?
My guess is a one way valve that is nessesary to stop the air pressure draining back past the compressor.

I agree the 240v differential pressure switch is the way to go.

You could also fit a air filter/water trap too if need be.

FollowupID: 13108

Reply By: Member - Cocka - Monday, May 19, 2003 at 20:19

Monday, May 19, 2003 at 20:19
None of these ideas sound dodgy but some are better than others. I guess it depends on your skills 'n needs.
Remember that you already have a tank & that is your spare tyre(s) that you can load up from any servo station. Check the max advisable pressure on the tyre, or with your friendly rubber man. To use this you simply need a clip on each end of a length hose to transfer the air, best to fit a small ball valve [in line] near one end. Also get a pressure nozzle with trigger for blowing out bugs 'n bits.
If fitting metal pressure tanks you can carry a lot more air pressure + volume, depend on size of tank. Again fit an inlet valve to pump the tank up from servo's compressor. I also believe that you would not have the moisture problems as compressors at servo's have taken the moisture out already. Set a pressure relief valve to blow off 25% under the max tank pressure. With a bit of luck you may not even have to use the little ARB. I call this the KISS method
AnswerID: 20457

Follow Up By: Kev - (Cairns,QLD) - Monday, May 19, 2003 at 22:04

Monday, May 19, 2003 at 22:04
You still get condesation on this system as i have a drain valve on the main tank and let the water out from time to time.

FollowupID: 13127

Follow Up By: Member - Cocka - Tuesday, May 20, 2003 at 08:38

Tuesday, May 20, 2003 at 08:38
Thanks Kev, I knew someone would tell me if it was wrong. But it was a reasonable assumption - but then again one should never assume anything.Carpe Diem
FollowupID: 13154

Reply By: kezza - Monday, May 19, 2003 at 23:16

Monday, May 19, 2003 at 23:16
Just a quick reply gotta be somewhere -I have an ARB compressor and a truck air tank (used for air brakes on trucks -most truck wreckers will happily be rid of them) mounted but seperate from compressor - its pointless blowing up tyres AND air tank at the same time. If need be I have an standard air line and an adaptor line I use to fill tank from compressor or garage or any other source. I use the air tank to get tyres back to a driveable pressure for bitumen after dropping pressure. Depending on pressure I get tank filled to - Tank will fill 2 tyres 32x11.50r15s from about 18 to 36 psi or put just enough in 4 to take out most of the bulge and top up with the ARB. The tank is invaluable when repairing tyres and needing lots of air fast but will only inflate 1 tyre from 0 to approx 23psi from flat.
I also use the compressed air for cleaning dusting inside of car, and any mechanical items. (all petrol engine owners should ALWAYS blow the dust and dirt from around spark plugs before changing them) and just about anything else I can think of. When I was younger I used to run a big air horn off an air tank I kept for similar purposes in my car (was a truckie at the time - not a hoon)

Most tanks like this are rated to 135- 150 psi most garages can supply similar pressure for a quick refill. I have a compact hose and air inflation,blowing and fitting kit approx $180 to set up properly if you can get all the fittings at the right price.

I just use standard air fittings on all my tanks and hoses. I am currently thinking about making an air line with a tyre valve (truck) in it so I dont have to take garages air line out of their system and plug mine in but havn't got around to solving a couple of simple problems.

Hope this helps,
just be careful when playing with compressed air, I saw an apprentice nearly lose his finger when cleaning a bearing mounted on his index finger with an air gun - the bearing blew apart at very high speed - (trap for young players)

AnswerID: 20491

Reply By: jaycee - Tuesday, May 20, 2003 at 18:50

Tuesday, May 20, 2003 at 18:50
The oiler and catchpot are necessary to keep the A/C pump lubricated as the japanese A/C pumps are not the wet sump types, ie dont have their own inbuilt lubrication system. If you access some of the Yankie 4x4 sites they talk about York compressors. These are the wet sump types and you can get them from your local wrecker, they are out of a "Volvo", its just finding a good one and paying the cost. You could alter the existing one in your truck but you will need the experts to add on a change over valve and some other bits. I didnt take that too far after most said they wernt interested and the odd one i did find wasnt prepared to guarantee the work.
AnswerID: 20591

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