Coolant Pumping Question..

[hotponyshoes]

Hi all,
Just setting up a workshop and we have 3 machines (may be adding more in the future) that need a cutting fluid / coolant supply.
We have a universal mill, a lathe and a power hacksaw.
Now, as the mill has a broken suds pump, the one from the lathe is missing and the hacksaw one only holds 2L I was thinking the best bet is make one tank holding about 30L, with one pump and just put a manifold on the pump to dish out the fluid.
My question is - whats the best way to control the pump?

I have thought of the following ways:
#1. I am using the loc-line stuff, so i could just wall mount a switch for the pump and fit taps to the loc-line on each machine so i just flick the pump on and open the taps on the machine i am using. I am just a bit worried that i will burn the pump out if it is switched on but i have all the taps closed (like i am setting up stock or somthing).

#2. I find some sort of pressure switch that i can fit to the manifold, so it will turn the pump on, build up pressure in the hoses, turn it off, then turn it on each time a tap is opened. problem i see with this is where do i find such a pressure switch and what if i am out of the workshop and a hose leaks? all my fluid will get pumped to the floor and the pump will run dry.

#3. I wire up the pump to a switch on each machine, a bit like the light switches you get on your stairs/landing. that way i could flick the switch on any of the machines and have the pump turn on or off. or i just wire all the switches in parallel so i can turn it on from any machine but for it to be turned off they all have to be switched off. only problem with this one is more work is involved if i add another machine and i have a load more high volt wires running around.

#4. The flash sulation would be to come up with some sort of realy arangement, wired into the power supply on each machine so when any machine is turned on the pump starts up. However the mill is 415v three phase and the other machines are 240v single phase so i would not have a clue about how to wire it and i would have the same problem with adding extra machines and also with the pump running under pressure if the machine was on but the coolant tap was turned off.

Any advice welcome!

[DSL PWR]

Use a centrifigal pump, as you can dead head the pump with no ill effects. I'd go with a relay for the pump, with separate switches. To minimize the wireing requirements get a relay with a low voltage ac coil, then use a door bell transformer, and door bell wiring. If you want to get fancy use a remote controlled relay, and leave a couple remotes around the shop.

http://www.nextag.com/remote-control-relay/search-html

[Pres]

What about the coolant return/scavenging system?

imho - just simply put a coolant system on each machine and save ALOT of headaches.

Pres

[RLC]

If time truely is money, then spend both and do 1 per machine, becuase it will never be on the machine you need to use....lol. I would also use the same parts on each system so I could swap parts should one fail...

[RICHARD ZASTROW]

I'd do 1 pump per machine. This allows different coolant/concentration for any machine if you so choose. If you're worried about voltage use 12v pumps from RV industry.

[hotponyshoes]

Time is not an issue but money is!
Pumps in the u.k run at about £80 (about $140) each.
All 3 machines are on the old side so replacement pumps are not available unless i can find them used. I could rig up any sort of pump i suppose but thats when i thought it would be easyer to have one central coolant system.
I was planning to feed the returns together. Each machine can have a 1" hose connected to the bed and i was thinking i would put some wire mesh on the beds to stop any swarf entering the hose then put one wire gauze in the tank to filter before going into the pump.
I dought we will ever use more than one type of fluid as this is just a hobby shop and thought that an increse in tank capicaty would help to keep the fluid nice and cool. I coukd either have 5l of fluid in each machine or 25-30l of fluid in one tank.

RLC - my idea was that one pump / tank could supply all 3 machines as it is unliklely that more than one will be in use at one time. Valid point about having spare parts though, with only one coolant system every machine will be out of action if the pump fails..

[Al_The_Man]

I would say it's going to be a pain, if you turn one one or adjust one it will affect the flow rate of the others.
If you only have one on at a time, you don't want the others running coolant so, you would need a in-line valve to shut the other two off.
or else I can see you for ever adjusting flow.
Al.

[hotponyshoes]

yea, i was just going to use a tap on each one of the loc-lines. this would come in handy anyway as the mill has two coolant pipes. one of those ring / 12 outlet ones for the vertical head and a wide flat pipe for the horizantal head. Allthough considering what you have to do to change it from vertical to horazintal i suppose un-clicking and re-clicking a few bits of pipe is nothing!

I think i will price it up and work out what the price diffrence is between 3 lots of pumps and one lot which then needs extra cable, realys and switches and see if the saving is worth having or i am better off with the ease of 3 seperate systems.

[hotponyshoes]

Just as a point of intrest, if the mill could hold 5L of fluid would you expect to be able to use it all day with out the fluid getting hot enough to burn skin?

[Al_The_Man]

would you expect to be able to use it all day with out the fluid getting hot enough to burn skin?

If it gets that hot your pump motor is even hotter!
The more flow the higher the motor current (heat).
5L is not that much. I thought you intended on a 30L tank?
Al.

[hotponyshoes]

Al- ok, maybe not that hot..
Listening to the above i am now weighing up between 1 pump for all machines fitted on a 30l tank with all machines returning to the same tank.
or, putting a pump on each machine, the tank in the base of the mill only seams to hold about 5l so if i was going to put a pump on each then i would use the tanks fitted to them (lathe holds 5l, saw 2l) i would imagine.
I was just weighing up wether going to a much larger tank could be a factor in my 1 pump / 3 pump debate..

[RLC]

Another thing is that on a central cooling system is the distance from the machine to the tank. Depending on the pump it may take longer than you would like for the coolant to reach the cutter (saw blade, end mill or lathe bit)
Then you also have to allow for the volumn that the feed and return lines can hold, it would suck to have several hours in a piece on the mill and turn on the bandsaw to cut some material and pump the system dry which would trash the project on the mill. As far as pumps I use a 12vdc bilge pump for the boating industry, they come is diffrent sizes. I use the 500gph (1900 liters per hour) one and a 30 gallon tank (plastic storage bin) less than $75.00 (u.s.) in the whole thing.