I have an open tank that will freeze over in winter. I was thinking of going with a bubbler system but was wondering if anyone has come across this problem before and used another transmitter like a capacitance or microwave and what the results were.

 

Have you ruled out a DP cell either 3" flange style on the side or you could just drop one of the submersible probes in from the top.
A bubble tube will work.

Radar might work but what if the ice layer doesn't follow the water?

Roy

 

If the top surface of the water freezes completely, it can create an issue for small tanks and give a false reading for a number of instruments. If it is a large tank, the weight of the ice should break itself as the water drops.

A straight forward pressure gauge, referenced off of atmospheric and not absolute vacuum should work fine if you have a low enough connection on the tank. The span of the pressure gauge should match the maximum height of the water plus a little. This will give you an accurate basis for the mass of the water. There will be a small error for volume of the water that will vary with the temperature.

Regards,
James Fountas

 

I am assuming that the water in the tank does not freeze solid, but only has a cap of ice on it. If so, you can use a submersible pressure transducer that sits on the bottom of the tank. They are reasonably inexpensive, too. In a clean water tank, they require minimal maintenance too.

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Yeah the tank is full and cement. DP will not work. However it is used for the fire system and there is a port on the intake of the fire pump where a pressure transmitter could be placed. What do you think of that?

 

Only if the gauge is heat traced & insulated to prevent its freezing. Bourdon tubes will fill with water over time, the air being absorbed into the water. When water in the bourdon tube freezes the expanding ice will either crack the tube or distort the tube, ruining the gauge's accuracy.

I vote for submersible.

David

 

Yes, you can use the pump suction connection but expect a bit of an error while the pump is running. I suggest you use one of the male treaded transmitters so you can close couple it to the pipe and so avoid freezing issue which you would get with tubing.

As I Walt & I suggested a submersible probe would be another easy solution, just drop it in the tank.

Roy

 

You can use the pulsar hydrostatic pressure transducers the gives you 4020mA out put. I have used for the ice thermal storage tanks that has glycol tubing centre of the the tank and hot water return from the district cooling.

find pulsar link here: web:www.pulsar-pm.com

 

In my opinion try to using DP (flange type) because Redar instrument very expensive.

 

Couple of questions.

One- Does the fill for the tank come in from the top or the bottom?

Two- Is this a short term freeze (overnight) or does it go on for weeks at a time?