Help make a Screw Compressor?

[hammered]

Hey guys I need help making a screw compressor.

I bought a wrecked atlus copco trailer mounted screw compressor.
Motor is toasted and a fortune down here.
I found it in the local scrap yard with a blown motor and no head.

I pulled the screw head and cleaned it all up.
There was some of rust but cleaned it all out and oiled in for storage in my shop.
Some pitting but mostly surface rust from sitting here with the high humidity.
It seems in good shape and should do the trick. Not perfect as I said some pitting.


I really don't Know Jack s*** about this type of compressor head.
I have lots of 2 stage units and want to eliminate these.
I need the High CFM for sand blasting.
At the moment I have a duel head 2 stage with double 5 hp motors.
Makes about 50 cfm.This is the biggest thing I could make with the 1 Phase electric at the shop.

I need more air for sand blasting blasting.

I have thought about looking for another motor but the 3 cyl diesel is a small fortune here and NFG.

Wondering if any of you work in this racket and could help me out with tips and advice.

As is the motor that was in it was pushing out 35 hp.
Wondering if I could hook up a 4 cyl gas motor with the same HP and use this.
I would set up LPG to keep the fuel cost down.


This trailer model here is well over 5K used and I got it for the price of scrap with the hope I could make this head work.
I can't afford the 5 grand or would just buy one and not mess with a wreck.
Thus far I am into it for about $700 in tools I traded with the owner.

The model is a copco XAD 96 if that helps any of you in this biz.
I could post fotos but not really any point as it is Fugly.

So what I am asking is can I use a 4 cyl. gasoline motor in place of the 3 cyl diesel?

Could I hook an electric motor single phase up to the head and change out the 2 stage heads I have?

Do these need the HP and high rpm or to make the CFM?

I used my Milwakee hole hog to spin the screw head.
Thinking maybe I could hook up a 5hp motor and spin it?
No idea what kindda CFM it would put out or if it would even work.

Any help & tip always appreciated.

Steve is Hammered on in CR.

 

[PAToyota]

I've been around screw compressors, but not sure how much help I can be on your questions. They do need the high rpm, so I'd lean towards the gas engine over an electric. I've been around electric ones, but you're talking high horsepower three phase units. You're not going to get far downgrading from a 35hp to a 5hp electric.

Looks like AtlasCopco Mexico takes care of Costa Rica: inferior a 500 cfm - 100 a 204 psig de Atlas Copco

I'm not exactly clear on what you're suggesting for the head. You say it is missing, but what are you suggesting to replace it with?

 

[hammered]

sorry about the mix up on the head.
Deal is I have no motor or the block has no head.
Beyond repair now.

I could drop a small 4 banger gas motor in for about a $150.
Thing is I keep getting mixed messages on the engine.
One say diesel only others say gas makes no differance.
I f I go Gasoline motor I will be hooking up Propane 1st thing.
Less than half the cost of reg Gas here.

Re the electric motor.
Ya I wish I had 3 phase and I would hook up a big ass motor but not an option and the Hydro Co will never upgrade my meter to 3 phase.

So will take your advice and look at dropping in a 35-45 hp motor.

Can I use Gasoline????

 

[PAToyota]

I'm curious as to why they say you can't use gas? Granted, a diesel will handle the all day loads of a screw compressor better, but I doubt you're looking at using it 24/7/365.

Deal is I have no motor or the block has no head.
Beyond repair now.

Still confused... Sorry.

Is it that you have two options? One without a motor OR one without a head?

Or do you mean that one unit is missing the motor AND the head - just have the block?

The screw compressors I've been around have the rotor housing and then the intake and discharge ports. Since it is a "flow through" design, you don't have a "head" like a reciprocating compressor with valves to control intake and discharge. So I'm not clear on what is missing. Anything missing will likely need to be replaced with the originally intended parts - I'm not sure how you'd substitute something else.

 

[hammered]

OK
No Motor just some rusted block of crap.
the rest is there up to the rad with cooling side.
No Engine.

My idea is use the existing flywheel that is big and heavy.
Will need to do some machining to get it to hook up to the crank.

My buddy has a Datsun 4 cyl 1800 cc motor for a 150 bucks.


Now what i need to know can I use it???
Not the same torque as the diesel.
Is the Rpm a big factor?
Seems to me these run about 3000 rpm.

Advice I got was that the diesel that it came with has large cooling cap. as it is a stationary. the Datsun isn't made to run 3000 Rpm sitting there.
I think he is right.
My thought is bigger fan and fact is the rad is 2xs the stock fan soooooooooo.....



Would hate to kiss it all up and find out it will not work.

I am going to run this 6 hour wide per day 2 xs a week max.


Yes a diesel will outlast gas but cost of maintenance is also much higher and I don't believe there is a savings here.

LPG Propane is the only option.

 

[Pin_Head]

I would be a little concerned about the condition of the compressor because I can't see anyone junking a high dollar compressor because of a bad motor, especially in a third world country. Motors are cheap in comparison. You might want to spin it and see if it develops enough pressure before you get too much money in it.

 

[hammered]

Ya 3rd world.
The government agencies have more $ than they know what to do with.
Was sold for $ as scrap.
It could have been fixed but someone told the boss it was scrap.
I see it all the time here.
See it in North America all the time also.

This junk yard is a treasure hunt.
I found a set of jaws of life in the mud a week ago. Figure that out?
Ya I bought it. Will be great for pulling dents.

They have miller xmt 350 they say is busted.
I am trying to buy it. if it cost me a grand to fix it will be a good deal.
They are 5 grand new here.


As for spinning the compressor.
I hooked up my hole hog and the head is pumping air.
No RPM.
I tore the screw head down to the bone and cleaned it all up.
I am sure it will work fine.

Sounds like the next move is hook up the 4 cyl. gasoline with LPG.
If for some reason it doesn't work my buddy will take it back.
Just time to mount it in the box.
The time is the important and most valuable thing and I am normally short of it.

thanks for the feedback

 

[Pin_Head]

Screw compressors depend on tight tolerances between the screws to develop pressure. When they wear out, they blow air, but not at a high enough pressure to be useful.

 

[madinal]

You may want to work in some kind of gearing since you only need 35 hp from an engine that probably has three times that. If you could gear it up, maybe a three speed manual transmission, you could run the engine at low or even idle rpm. Also you may want to look into an electric fan on a remote (outside) radiator.

 

[hammered]

Now you have me worried Pin:

I did spin it with the drill and it had pressure but I could stop it with my hand.
Very low RPM Hole hog drill????
At 3000 rpm I doubt I could block the flow.

Idea of the trani is cool.
Ya it would cut costs but would like to keep the package all mounted in the same trailer.
Just swap out the engine.



Any of you know if these are wet or dry compressor heads?
I was reading online and found there are 2 types.
I am thinking this is a wet.

 

[yotawheeler]

iv seen it happen with a big IR compressor unit that somebody got a little too ether happy on and blew up the engine....company just gave the compressor away for nothing because a new engine is worth too much to warrant fixing...so somebody in the shop got a steal of a deal and will probably just put a little 4 banger gass engine in it and be happy.

far as this goes i would say try the gas engine from your buddy and toss that in there, if not maybe a little 2cylander engine out of a wrecked street bike? this would probably put out enough HP and rpm's and could probably be found easily as well...

 

[hammered]

Interesting you mention the bike engine

This crossed my mind and thought it was stupid.
Your right though 35 hp is nothing for a bike.

I guess it can't get easier than a 4 banger and the price it right so will try this out.

Not time this week thought.
Finally starting a new contract.
Good quality container so not much blasting to do.

Thanks for the input guys and I will update this thread when I am running it.

Pura Bira