I finally got my 2.2 kw water cooled spindle running. Every time the spindle stops and the coolant pump stops a bunch of air bubbles up from the spindle into the discharge hose. The water flow is good while the coolant pump and spindle are running.
I have the coolant pump connected to the IoT to start when the spindle gets to 5,000 rpm. I do not have the Kool quick disconnect fittings. I bought 6 mm diameter barb fittings on Amazon. I am using fuel line clamps on the superthane tubing to seal the joints. (I could not get the superthane through the nuts on the stock fittings.)
Should I be concerned about the air trapping in the spindle? What is the best way to purge the air from the spindle?
Depending on how many air bubbles you’re talking about, it’s nothing to be worried about as far as the spindle is concerned. A bubble or 2 maybe 3 when first turning on is what im referring to.
If it’s quite a bit, an air leak will develop to a water leak eventually, and that is the greater concern.
When i had an leak, the first step was to identify the source. It should be fairly easy to do by manipulating the hoses and connectors to see where air is introduced.
There is about 12" of air in the return hose from the spindle every time the pump is turned off.
There are no bubbles in the hose into the spindle so the air is being introduced in the spindle.
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Yeah, that’s quite a bit. The advantage of the kool connectors is that it’ll stop the coolant in place, being how you don’t have them, I would verify your hunch its coming from the return line.
If it is, there’s no problem, and not to worry.
The the air is introduced some other way, that is a problem that will only get worse. Not the air getting in, but the route its getting in would let coolant out.
I found a tiny leak between the hose and the barb fitting with the fuel line clamp that was pulling air in. I used the trick of cutting the hose end at a 30 degree diagonal to allow the the hose to be pulled through the factory nuts that Clinton suggested and reinstalled the factory fittings. Problem solved.
Please put the “cut the hose at a 30 degree diagonal” trick in the documentation.
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Had the same problem, I sunk the return line into the water, and have not had the problem since. No place for air to enter unless you have a major air leak someplace else, if that were the case when the pump was running you would see the water squirting out.
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Maybe but not necessarily. The leak would have to still be big enough to facilitate that. A small enough pinhole wouldn’t create that effect.
I had a leak a long time ago (before the vfd had an enclosure) at the kool connector, and it was barely dripping, the indicator was (aside from the puddle over time) was the steady stream of air bubbles.