Cooling fluid in a K40

[NickWL]

I have just rebuilt the cooling system for my K40 using a 35 litre water tank and an aquarium chiller; this is a more-or-less-sealed system - but not sealed tight enough to fill and forget.
What can I add to the water that will prevent fungus, algal and other nasty growth?
I used a supermarket disinfectant before but it was a bit inclined to froth ('contains <5% non-ionic surfactants').

Thoughts please...

[Tech_Marco]

Use automobile coolant. You may want to dilute it by distilled water in 50% or 75%. No fungus or algae should be able to built up
For fresh water (distilled water), it will get germs in about 2 weeks and feel slippy.

Give it a try

Marco

[NickWL]

Thanks Marco - I'll try to get some tomorrow - shame it's almost mid-summer here!

[NickWL]

Marco please: what is the ideal temperature setting for the cooling water in a K40 with DSP controls?
AND
Can I use bleach instead of antifreeze?

[Tech_Marco]

Temperature should be kept 28'C or blow. For most laser tube, 22~25'C is perfect working temperature. If you don't have a water chiller, then get a 5 gallon water tank and a decent fan to blow the water on a damper clothes. You may reached unexpected result

I don't recommend using bleach as it will damage the pump shortly. Chlorine is very corrosive


Marco

[Poltergeistas]

what spec water pump should be used to cool down 50-60w tube? ??L/min?
I have original k40 water pump but now I'm upgrading tube to 50w tube with water flow sensor.

[Tech_Marco]

Get the 10L better for the tube
Make sure it has better "Head rate", the lifting distance.
For a 10L with low head rate 3ft or so, it won't give you a decent flow rate if you have to bring water from the ground level to the the laser tube over 3ft range. You may end up "zero" water flow!


10L:
http://www.lightobject.com/10Lmin-158GP ... -P511.aspx

12L:
http://www.lightobject.com/High-perform ... -P839.aspx


Marco

[brian257]

Marco, is 28 degrees C correct? That works to 82 degrees F. In my shop in the summer in Florida the air temp can easily be 95 degrees F. How much will that decrease the life of the tube?

[Tech_Marco]

Yes 28'C or less.

F = C*9/5 + 32
F= 28*9/5 + 32 = 82'4 F

If you're using air-cooled radiator and if the room temperature is 95'F (35'C), the life span of the tube will be affected but I don't know by how much

I'll use water evaporator instead. It is simple solution. Just get a bucket of water and a fan blowing on the water that is circulating the tube. That should do the trick for 60W or smaller laser. I was thinking to launch my simple "DIY" water cooled system (no compressor but water pump, fan, and a bucket only) but was too busy to finish it.

FYI, using this method the climate over that location should be dry type. Florida is kind of humid right? If so, the efficiency of using this way to cool off will be lower.


Marco


Marco

[NickWL]

Marco - I run my coolant at 18.5-19.5 degrees C. Is that TOO cold?
I always reckoned that electronics liked to be kept pretty cool...

[Tech_Marco]

As long as not getting closed to the 'dew point' (forming moisture), it would be fine.
Second condition: do not operate the tube without warming it up first if water temperature is more than 10'C in differential between water and the room temperature. If it is over 10'C, chance of having thermal shock could highly possible when operating high power laser tube. Extra caution required when operating a 150W or higher wattage laser tube. No sorrow if it cracked due to careless consideration


Marco

[NickWL]

No sorrow for Marco - but BIG sorrow for he who cracks his 150 watt tube through stupidity!!

Yes, Marco, I always allow the system to stabilise its temperature before starting - it usually takes 10-15 minutes of running the water system before firing the tube.
Good advice.

[Tech_Marco]

It did happen before. A customer bought a Reci 150W~180W tube and cracked after 10min. The tube was shipped to Europe and it was winter time there (8~10'C) if I'm not forgotten. The crack should be the cause of "thermal shocked". Customer insisted that water chiller was using and water temperature was within limit (less than 10'C differential). Anyway, no argument here but need to be positive when dealing a problem rather than accuse.

Lucky, since we're well known by the Reci agent and they trusted. After I requested a video, pictures, and a brief explanation what had happened from the customer, I got a replacement for him and the customer was willing to pay for the shipping cost. So, there was no 'flight' but win win situation. When things happened, I admired my customer have faith on me and be reasonable. I do what I can do to get the problem solved.


Marco