Compressor advice

[t_torrans]

Folks

Feel like a bit of a numbskull asking but here goes.......

I have a Sealey 3hp compressor with 50l tank (bought second hand). Seems, and might just be me, to run slow when using an air-drill but tank and output pressure gauges read solid - 90 psi + with both reading much the same.

Connected it via air filter/oiler with a separate gauge. The reading matches the compressor dials with no load but as soon as I use the drill the air filter gauge drops to about 2 bar (from 6). If I up the starting pressure to, say 7/8 bar, it still drops on the air filter gauge to same level. Gauges on compressor show a gradual drop until the motor kicks in again and tops up.

My silly question - does this sound right or not? If it isn't right, any suggestions?

Thanks

 

[gordon stephenson]

Hi,
Maybe that the filter/oiler can't handle the amount of flow you require? and as soon as you operate the drill etc the pressure in your line to the tool drops to the low level you mentioned,
Cheers Gordon.

 

[rtbcomp]

Welcome to the forum.

Yeah, get a regulator with a 1/2 BSP fittings and fit it straight to the tank.

Have you got a pic of your setup, we may be able to give more specific advice

 

[t_torrans]

Thanks guys & sorry no pictures - a lock up so will take one next time I'm over.

Relatively straightforward setup - compressor with airline connected via quick coupler to air filter/oiler fixed to the wall. Air line from filter to tools via coupler. Two gauges on the compressor (tank pressure & outlet pressure). further gauge on filter/oiler.

From the replies I'm guessing I shouldn't see the drop in pressure between the outlet & filter gauges when using the tools (outlet gauge on compressor at 0.6 bar, airfilter gauge dropping to 0.2)?

The outlet gauge doesn't show the drop but I deliberately put the filter with a gauge in because I thought the drill was running slow when connected direct to the compressor (apart from the benefit of oiling the tools etc) - seems to be a surge then settles.

So that bit could as easily be me not used to air-tools and assuming same speed as electric drill - never used airtools before. But compressor should have enough to run the tool (12 cfm against required of around 4 cfm I think).

 

[Luke]

Sounds like you've got a restriction on the output of the compressor.

My Clarke comppres came with an orifice fitted in the outlet of the compressor, to limit the flow out of the tank. It gave exactly the symptoms you describe.

I now run anything off that tank, straight off the 1/2 port, as already mentioned above.

 

[t_torrans]

Luke (& Gordon)

That makes sense had thought I was just being stoopid or going mad! Attached link shows the compressor I have:
http://www.sealey.co.uk/PLPageBuilder.asp?gotonode=ViewProduct&method=mViewProduct&productid=11149

If I understand correctly you've connected direct to the tankl before it goes into the little black box (which houses the cut-out, safety release and gauges) or do you mean direct from the output on the black box before it gets to the outlet gauge (second gauge on the far right in the picture)?
If connecting direct to the tank does that mean the pump runs continuously?

Continuing to feel guilty for sounding like the air-head!

 

[rtbcomp]

Connect your regulator into the port in the end of the tank. It won't affect the operation of the machine.

If the output on yours comes off the black box that's 1/4 BSP, no way big enough for airtools.

Make sure the tank is empty before removing the bung, and you may need to heat it to release any locking compound.

 

[t_torrans]

Gotcha!

Was worried when writing last post - had visions of tank exploding without the regulator. Knew I had misunderstood.
One final (set of) questions, if you'll be kind enough to humour me, but what size of air hose should I be using for the air tools bearing mind most of them have 1/4 BSP connectors, or put another way is it just the outlet on the tank that's important as opposed to the tool inlet?

By the way, really appreciate the help offered - best forum I've ever used for advice from experts to my total lack of knowledge.
Thanks to all

 

[Jaeger_S2k]

I'd say 1/2 to the tool then reduce for the tool. That way there's greater volume in the pipe/hose than the tool can demand, bit like having a long thin receiver attached to the big reservoir.

 

[rtbcomp]

I'd be inclined to use 10mm bore, losses in the connectors aren't as significant as losses in the hose.

One thing you could do is connect the hose directly to the tank and place the regulator nearer to where you are working, this will mean most of pipe is at high pressure, thus reducing losses at the tool.