Can I blow up the Compressor Resevoir?

[ImanCarrot]

I have a Compressor which delivers air to a Resevoir Tank (about 2 diameter by about 4 foot long)- in between them is a Delair System to "dry" the air.

This air then goes to my machine to support the X, Z slides and the spindle.

My problem is that since it's freezing outside, the air seems to be chilling the spindle and slides giving non- repeatable results as the spindle warms and cools along with the slideways.

What do you reckon to sticking some sort of heating around the Air Resevoir Tank? Or is there a risk it would cause something to go bang?

The whole system is operating around 120 PSI

Many thanks in advance.

[svenakela]

Is the machine driven by air?!

[ImanCarrot]

Thanks for replying

Yes, it's an air bearing spindle, the axes are "raised" by air and are moved by precision leadscrews with optical encoders to get the position feedback.

Additionaly, it's parked exactly by the back door where I go for my ciggy break... I really don't want bolts, nuts and bits of pipe whirring by my ear at 120 PSI if it does go pop!

[mxtras]

Heating it up would be ok as long as the tank is not completely sealed during the temperature rise and you don't go crazy with the temp. Just like when you first fire up a hot water heater - you have to leave a hot water spigot cracked slightly to bleed pressure increase - you might want to allow for a small air leak during the tank heat up process to eliminate the temperature induced pressure build in a sealed vessel.

What is the CFM of the operated devices on the machine? Is it the main volume consumer from the compressor? My thought would be to warm the air for the machine only and leave the rest of the supply alone, but I don't know your set-up. If your compressor mainly serves the machine alone, then what you are talking about makes sense, I suppose. I think you might have a better chance by heating the supply line or building a heating section in the supply line. Without getting rediculous with cost, I am not sure how you could get enough heat in the air in the tank - seems like it might be easier to heat a few lengths of copper pipe (depending on volume) with self-regulating heat tape - or something like that.

This is an interesting dilemna....

Scott

[AtomicBeaker]

Surplus Center has a few reasonably prices pressure relief valves;

http://www.surpluscenter.com/item.as...-1370&catname=

http://www.surpluscenter.com/item.as...-1536&catname=

[ImanCarrot]

Thannks Mx. I opened the compressor up and had a look for the CFM rating but couldn't find it. It's got to be reasonably high though:the actual pump itself stands about 2 1/2 feet tall and is around 3/4 foot diameter. It has an 8 litre capacity.

I'm thinking though that if I heat the pipes themselves when they come back into the building I will have the opposite problem- ie air too hot: the spindle does have liquid cooling but it's boke, so I might fix that and try your suggestion.

Thanks Beaker, my releif valve at the moment looks a bit grubby and rusty... I think that could do with replacing anyway

[ViperTX]

I have to assume that the air supply is rigid pipe, most likely steel pipe...if this is so then pick-up a few of those pipe warmer strips that you wrap around water-pipe and plug into an AC source to keep outside water pipes from freezing.

If the pipe if flexible...as in rubber / neoprene house then you could coil up some and immerse it into a container filled with water, the container and water being warmed by something like a hot-plate.

[mxtras]

The tape you are talking about - self regulating heat tape - I just don't think it has enough arse to make much of a difference in such a dynamic application - it's made to overcome environmental changes, not processing changes.....hence the reason for the questions concerning volume.

Good suggestion with the hot plate, Viper. That's a very good idea - a coil of copper tubing submersed in warm water in a bucket - easy to regulate and control, easy to build, safe.....good idea!

Scott

[lwill]

Be sure to keep your tank drained! The water could freeze and that could/will cause the tank to blow.

[jderou]

Wouldn't the air expansion [cooling effect] at the spindle pretty much negate the effect of heating the source? I would think you would have to heat the source pretty significantly to make any difference at the spindle.

[ImanCarrot]

Quite a few good ideas there, many thanks! The pipes are 1.5" dia plastic and go stright from the compressor up to the ceiling level. They then enter the building and go across the roof to my lab.

I'm gonna see if the boss will fork out for a new air "dryer" with temperature control although I can hear the answer already hehe

[2muchstuff]

Air bearings/spindles, slides in total will use a fair amount of air. Using that much air will cause the cooling effect that you have described. Due to the amount of air that you are using, heating the tank or lines will have little effect. You could even heat the tank with a torch and have only a marginal increase in temp. From your description it sounds like the compressor is outside and so is it's intake, sucking up all that cold air. The compressed/heated air is being fed into a cold tank and pipe.

If you can move the compressor inside or at least run a hose from the intake to the inside where the air is warmer or bring the high pressure line inside right after it exits the tank, don't let it run up the wall outside.

Last resort, get the liquid cooling working again and run warm water thru it but that would only take care of the spindle and not the slides.