Enclosure Water Drains

[TimWilborne 108]

So I have been working on my Flash Welder and have got my enclosures mounted on it. I was working on how to route some water lines to it and realized I might have a problem down the road. They are mounted to the sides of water cooled transformers plus one of the enclosures contains a water cooled SCR. What's going to happen if one of these line bust? With the old enclosures it was not a problem because of poor sealing of the conduit and it was full of holes from the years of modifications I know I'm going to need some drains but I'm trying to figure out what to use and how large. The water pump is 40 gpm. There will be two 3/8 line going up to the panels so I guess the worse case scenario would be both lines being cut. The old lines never leaked a drop in the enclosure but you know how Murphy's Law is. Anyone got any suggestions?

[BobLfoot 301]

Few Quick Thoughts. 1. Be sure you have deflectors in place so a pin leak could not direct spray your electronics. Lexan works great. 2. You have 3/8 flow in and 3/8 flow out. A leak in the cabinet would mean a serious drop in exit pressure. They do make differential pressure switches which could then close a solenoid turning off water to the cabinet. 3. Could you create a sump well within the panel to catch leaking water and pump it out. This would maintain integrity of the panel.

[TimWilborne 108]

Actually there is two 3/8 flow in, 2 3/8 flow outs There is a manifold for the water with 6 3/8 ports, two of which go here. 1/3 of the 40 gpm flow? Here is a illustation

[BobLfoot 301]

You're assumption about 1/3 the flow is not totally accurate. Given equal piping resistance then each Pressure/Return Set will take 1/3 the flow. But when the line in the enclosure ruptures it provides a path of least resistance and will consume more of the flow in an attempt to equalize pressure. I still think the Diff Pres switch is a good way to go. You'll also need a check valve on the return line possibly. That and splash plates should cover every thing except transformer to enclosure rupture.

[TimWilborne 108]

Is the differential pressure switch just a mechanical switch that shuts off the flow if the pressure and return flows are not equal?

[TConnolly 13]

Tim, You remember those pictures I sent you of the SCR puck packs and that bar-b-qued transformer? We had a good hot dog roast that day. :D I don't know if you noticed or not, but the conductors of the transformer secondary are copper tubing through which water flows. The SCR pucks are water cooled and there are also three water cooled heat exchangers mounted in the cabinet to cool the air down. We do a few things: There is a cabinet drain. It is and optically blind hole, that is you can't see through it. There is a stack of baffle plates over the hole. The idea is to let water out of the cabinet while impeding the easy flow of air and the contaminents it carries with it. We have flow meters on the OUTLET of the cooling lines. We check the outlet, not the inlet, because if you have a hose cut loose inside the cabient you will still have water flowing in and none flowing out. There is one meter for each flow circuit in the machine just before they recombine into the outlet manifold. The water supply system is completely closed circuit. It uses a closed slighlty pressurized tank. If any makeup water flows into the system then we know immediately that there is a leak. The water flow is interlocked to the main power switch gear for the unit. No water flow, no power. Edited 7 Sep 2006 by Alaric

[TimWilborne 108]

Now why didn't I think of that. I have flowmeters on them currently but they are on the inlet. I will move them to the outlet. Would one of those wire mesh filters you see installed on some panels work for the "Optically Blind Hole"?

[TConnolly 13]

I suppose it would work - anything to keep contaminantes out. With any kind of a drain your cabinet will no longer be Nema12 or Nema 4, if its even that now.

[Snerkel 0]

Another addition may be to use a bagging over the water hoses, so you end up with a double skinned hose. End inside panel is sealed, end outside is open into a small tank or a bund. Level switch in the tank, any leaks no matter how small end up in the tank/bund, and even small leaks will eventually trigger level switch. System used a lot in chemical dosing.

[TimWilborne 108]

Good idea. I will look and see if it is possible Thanks TW