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Central coolant system.

Friar

Plastic
Joined
Dec 11, 2021
We're on the verge of moving our shop and running coolant to each machine was high on the list of things to do. We checked with qualichem and our coolant shouldn't attack the pex plumbing but someone had suggested the coolant in the lines might go bad in between top off's. Seems plausible since it's just sitting there not getting circulated. Plan B is to run straight water to each machine, which would be a big improvement over where we're at now. Plus side to this is we could run water all around the shop from one line and not need a second line for just coolant. But I figured someone has been through this so thought I would ask. Also looking for a coolant mixer if you have any recommendations.
 

GENERALDISARRAY

Hot Rolled
Joined
Jan 3, 2019
if its fresh coolant I dont think it will sour in the lines.
Are you going to mix into a vessel in batches and then feed that into the system? If you want to go from concentrate to the system it takes a special mixer.
 

MaxPrairie

Hot Rolled
Joined
Jul 9, 2015
Nyccnc had a shop tour of a slick central coolant system. I will link it once I remember which one. We also use quali 251c in 55 gallon drums with a self mixer in the bung. Works pretty well, just dial what percent you want the coolant to come out and fill. It may be made by zebra. Red block with a 0-10 dial.
 

Friar

Plastic
Joined
Dec 11, 2021
Was hoping to mix it as it goes into the line. Having to batch it first feels like a wasted step.
 

guythatbrews

Cast Iron
Joined
Dec 14, 2017
Location
MO, USA
If you go to the trouble of running lines fill them with coolant not straight water. If you let operators mix at machine no telling what you'll get except more is better!

Good coolant proportioner of course, not a suction deal. Master chemical makes a good one as of about 10 years ago.

Ask your coolant guy if souring will be a problem, unless he is a blowhard. If you are worried run rigid PVC and pitch back to tank to drain lines. Would be cool to run low voltage line along with coolant line back to pump to turn on from machine, and very little more work. Cheap power supply and wire use outdoor lighting stuff to dc relay.

Machine side do not use a valve that can be left on unattended. Eventually operator will walk off and leave on and you'll have a mess. Saw a guy prop open a spring return valve on a full drum of vactra 2. Forgot and ran it empty over lunch. It was messy and expensive.
 

Scruffy887

Titanium
Joined
Dec 17, 2012
Location
Se Ma USA
The Mazak plant in Kentucky has a central coolant area where all coolant is supplied to the machines, and also returned to central. Constantly circulating and getting tested and filtered. We saw it as part of the tour and I remember we were on a catwalk far above the machine floor and the coolant was raining down into a collection pool below. This area was sealed with a glass wall. For sure the other side of the glass was a bit grimy, prob needed frequent cleaning.
If you are going to put supply lines in you may as well as put return lines in at the same time. Now or in the future you add a return pump with a float valve at each machine, over fill alarm too. Constant coolant circulation allows you to have a much better and efficient filter operation, and takes the operator out of the equation. Running both lines is the start and you add the return pump/float units as time and $ allow.
 

MaxPrairie

Hot Rolled
Joined
Jul 9, 2015
Some tool grinders have a central coolant system mostly to control the temperature of the coolant. I do not think this is what his goal is. Just wants to get away from buckets.
 

Friar

Plastic
Joined
Dec 11, 2021
Some tool grinders have a central coolant system mostly to control the temperature of the coolant. I do not think this is what his goal is. Just wants to get away from buckets.

The primary goal is just to get away from the coolant bucket brigade we currently do. But this does bring up an interesting question, at what point does coolant temperature become an issue? We typically hold tolerances to +/-.001 so nothing super tight. The thought of running a return system to central filtration hadn't really crossed my mind but that could be a good second phase to this project. All the lines are getting mounted to unistrut that's in the open so adding that down the road won't be difficult.

And yeah, definitely going to do some kind of dead man valve so people, my self included can't flood the shop.
 

MaxPrairie

Hot Rolled
Joined
Jul 9, 2015
I would not worry about a central temp controlled coolant system at 1 thou tolerances. It wouldn't have enough heat exchange to pull excess heat for the casting and ways. If you were concerned about thermal growth you would be looking at machines with excellent thermal compensation. The grinders I know using these coolant chiller systems are grinding micro endmills and drills to tolerances 10 times what us mere mortal machinists worry about.
 

guythatbrews

Cast Iron
Joined
Dec 14, 2017
Location
MO, USA
Gosh maybe 30 years ago I went to the master chemical coolant school. For full on main sump systems they talked about dead spots in the piping where there was little to no circulation due to faulty design and magical fluid dynamics laminar flow issues. These dead spots are harbors for very nasty jelly like fungus growths.

I very much get the desire to avoid the bucket brigade and piping fresh coolant to the machines. That is easy. The full on thing is hard and not really much gain for the avg shop I would think. Diminishing returns comes mind.

Maybe think about a timer instead of deadman switch. My finger gets tired thinking about a deadman.
 

CITIZEN F16

Titanium
Joined
May 2, 2021
Machine side do not use a valve that can be left on unattended. Eventually operator will walk off and leave on and you'll have a mess. Saw a guy prop open a spring return valve on a full drum of vactra 2. Forgot and ran it empty over lunch. It was messy and expensive.

It is amazing how far a small amount of liquid will spread across a level floor.
 

Orange Vise

Stainless
Joined
Feb 10, 2012
Location
California
Every machine consumes coolant at a different rate.

For that reason, we run straight water to each machine and mix at the machine. We buy multiple drums of coolant at a time - the price adds up, but it's not like we're consuming more coolant. We're just buying more upfront.

There's no substitute for human intervention. Machines simply cannot maintain their own coolant.
 

DavidScott

Titanium
Joined
Jul 11, 2012
Location
Washington
The primary goal is just to get away from the coolant bucket brigade we currently do. But this does bring up an interesting question, at what point does coolant temperature become an issue? We typically hold tolerances to +/-.001 so nothing super tight. The thought of running a return system to central filtration hadn't really crossed my mind but that could be a good second phase to this project. All the lines are getting mounted to unistrut that's in the open so adding that down the road won't be difficult.

And yeah, definitely going to do some kind of dead man valve so people, my self included can't flood the shop.


How much the temperature of your coolant matters depends on the size and thermal growth of your parts. If at all possible I would try to do centralized coolant so you are only maintaining one coolant tank vs many. You could take better care of it and if done right you would need much less mixed up at any one time, but it is no small feat.
 

Friar

Plastic
Joined
Dec 11, 2021
Every machine consumes coolant at a different rate.

For that reason, we run straight water to each machine and mix at the machine. We buy multiple drums of coolant at a time - the price adds up, but it's not like we're consuming more coolant. We're just buying more upfront.

There's no substitute for human intervention. Machines simply cannot maintain their own coolant.

We were thinking we would run the central system light (~4%, we typically run 7-10% depending on material) and adjust at the machine as needed. We're based in the Oregon desert so we definitely get a decent amount of evaporation. Plus side, we don't have to worry about our steel parts rusting in the shop like I imagine you guys do in SoCal.

And yeah, I don't have any hopes that this is going to be an automated system that can set and forget. That sounds like a pipe dream that leads to a shop floor covered in coolant when some component fails. I just don't want to have people carrying buckets of water through the shop.
 








 
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