air compressor problem

We have a small air compressor similar to this

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On start up it will occassionally struggle to get up to speed. It just rumbles and rocks. Has to be turned off and on again.

Is this likely to be easily fixed

Reply to
fred
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A couple of things ... I'm guessing the motor has a start or run capacitor and if that has gone (or is going) that it will effect the overall performance of the motor?

When the compressor comes to pressure (assuming it ever does) and / or you turn it off using the knob on the top of the control box, you should hear a 'Tish' as it dumps the air out of the pipe between the output of the pump and the reservoir. This allows the pump / motor to start up against no pressure when it turns on the next time and if that wasn't working on yours (stuck open one way valve where the pump hose joins the cylinder, or it could be stuck closed, offering too much back pressure etc), that might have something to do with it?

You could try disconnecting the output hose from the pump (with everything de pressurised) and then turn it on and see if it all spins up quickly?

Not directly related but have you ever drained the water off? I was given a small / silent compressor that seem exceptionally heavy for it's size and it seemed to come to pressure very quickly, and then have no real capacity. The cylinder was actually *full* of water as it had never been drained over it's entire life! (it was used to power a liquid foam packing gun for a company). [1]

Cheers, T i m

[1] I found a 25L 'Wolf' cylinder (new) and took the silent Bambi pump off the 9L cylinder and made myself something better. ;-)

By better I really mean 'a very quiet compressor', something both my Tinnitus and neighbours appreciate. ;-)

Not cheap to buy new though ... (for the capacity etc):

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Reply to
T i m

fred has brought this to us :

Is that starting with or without any air pressure already in the cylinder?

Reply to
Harry Bloomfield

Thanks for that. I'll have a look at it tonight.

I have a Bambi also and being slightly hard of hearing I cannot hear it run With hearing aids in place it is just barely noticeable. Such a relief from the racket created but its predecessor

Reply to
fred

You are welcome. ;-)

They are amazing, considering.

Even more so eh. ;-)

Quite. I do also have a 50l twin cylinder jobby but resist using it because of the noise. It really is nice to have the function of a compressor that will pump up a car tyre from flat, all be it with a couple of goes (while the pump catches up).

For general air blowing / dusting, cycle / trailer tyres, popping pistons out of calipers and doing so whilst standing next to the compressor and still able to hear the radio ... it's ideal. ;-)

Cheers, T i m

p.s. One of the best improvements my mate made to his (commercial) garage is to put the big / 3 phase compressor in a side building. Before he did, if it ever fired up while you were talking, or he was on the phone ... you either had to stop and wait or turn it off!

Reply to
T i m

Try adding a storage tank in the air line, it improves tyre inflation for large tyres.

Reply to
Capitol

1) No, really ... adding more storage capacity will give more storage capacity? Left brainer, please try to remember you are talking to a right brainer and so the chances are all the possibilities have already have been considered. ;-)

In fact I even have a portable receiver that I could (effectively and easily) add in parallel to the output do just what you say but I prefer to use it portably and there is insufficient regular / reliable requirement for the extra capacity to justify the extra space, plumbing and maintenance required.

2) Adding such to the output will only ever realise it's full advantage if the compressors output pressure regulator it set on maximum. It would be far better to add it in parallel to the compressors receiver itself and in that way it can easier make use of any in-line filters etc.

Cheers, T i m

Reply to
T i m

istr carpenters on building sites in America using domestic gas cylenders t o power their tools where a compressor wasn't viable. Wouldn't require a lo t of plumbing to connect to the compressor. Once the top of the gas cylinde r had been modified to accept a standard snap lock connector it could be us ed to attach the tool and with a short length of hose used to refill the ga s cylinder. No idea what pressure these gas cylinders would hold.

Reply to
fred

Hmmm ...

Understood.

Rather than risk anything like gas bottles, I have one of these:

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Not particularly expensive and about the biggest size most would consider portable.

Cheers, T i m

Reply to
T i m

Hmmmm but the ghas bottles are free !

Reply to
paul.mccann

So is a trip to A&E. ;-)

Cheers, T i m

Reply to
T i m

You've seen "No country for old men"?

Reply to
newshound

I think they have it marked on them. From another site, I got the following for 47kg propane bottles - Working pressure 240 psi, test pressure 480 psi, design burst pressure 960 psi.

SteveW

Reply to
Steve Walker

And the gas bottles have a collar so if they fall over or roll around, the valve can't get smashed off the pressurised tank.

BTW I also read that the 47kg propane bottles have a BSP thread when you undo the valve, I don't know what the 32 pounders have.

SteveW

Reply to
Steve Walker

That is a good thing. I was thinking of building a wooden frame to sit mine in but it's not been an issue so far.

Do gas cylinders usually have a welded seam along their length as I believe compressor tanks usually do and are placed at the bottom so if / when they do fail, or if they are in a fire etc.

And how would you drain the water out of an ex gas cylinder (short of turning it up side down etc)?

Cheers, T i m

Reply to
T i m

I don't think I'd want to be close if it let go at any of those points, especially when it was full of gas. ;-)

Don't the fire brigade often report seeing (oxy and?) acetylene bottles flying out of industrial files like fireworks?

Cheers, T i m

Reply to
T i m

Piddling little pressures!

I used to design control and instrumentation systems for industrial compressors, typically with pressures of between 49 bar and 210 bar. The smallest had a 330kW motor, the largest electric one an 8MW motor and others with 24MW gas turbines for the high-flow pipelines crossing Germany into France.

When I left, they were just quoting for a unit with a discharge pressure of 125000 psi for a polyethelene plant.

They do tend to worry about them and concentrate on spraying them to keep them cool.

SteveW

Reply to
Steve Walker

;-(

Ok.

Feck!

The thing is though I'm assuming that all the safety features would be in place for each system or that they were intrinsically safe because of what was under pressure (gas / liquid / molten plastic etc)?

Like, I know they often test pressure vessels (steam boilers, gas bottles, compressor reservoirs?) using water because if they do fail there is little chance of anything nasty happening?

And I think they carry on spraying them for some time after the main fire is out.

Cheers, T i m

Reply to
T i m

I was surprised the toolsatan portable tank linked earlier *didn't* have any protection to the valve/gauge. Maybe it comes with an instruction leaflet saying it must be emptied before being carried anywhere :-P

Reply to
Andy Burns

Me too in a way.

It did come with some form of (scant) instruction and OOI I'll see if I can dig it and let you know. ;-)

Cheers, T i m

Reply to
T i m

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