Level Control Sensor

In putting together my RIMS system I have acquired a level sensor: http://ecatalog.gemssensors.com/ecatalog/warrick-controls/en/16HMJ1A0

I'd like to use it to shut off power to the heating element if it doesn't see continuity between two points in the RIMS tube. I've got it figured out from an electrical standpoint but I am not sure how to approach this from a physical standpoint.

I was thinking about drilling two holes in the rims tube and filling them in with JB WaterWeld with the two sensors centered in each hole so as to not make contact with the stainless steel tube. I'm a little bit leary about chemical leaching from the waterweld (I know its not much and shouldn't be a big deal) and I don't like the permanence of this idea in case one of the sensors becomes fouled.

I have also thought about drilling holes and threading them (it's sch40 pipe) to put some plastic plugs with the sensors imbedded. But I am not sure if I will run into problems with different materials and thermal expansion, etc.

Does anybody have a more practical suggestion? Maybe a combination of the two would be a best bet (tapped hole in pipe with Waterweld as a backup seal).

That's an EXPENSIVE sensor. Why not try something like this instead: http://ecatalog.gemssensors.com/ecatalog/singlepoint-level/en/131100

It's a lot cheaper and can do the same thing.

I've already got the controller, the price was right (free). I'm just having trouble thinking up sensors.

I am thinking about getting a few PTFE screws and pressing some stainless pins in sort of like this:


I was just hoping for something a little bit simpler.

I think he is trying to use what he has, however a similar Grainger 5DYC2 is $11.57 it is rated for 105C(221F). For boil, a higher temp (150C)rated one is 4YM36 $25.15

or you can get a stainless one on eBay for $21.89 item # 230678576542

Hot tubs use an adjustable pressure switch in their heater tube... as long as you restrict the output a little, there will be pressure... but your idea should work..

the best way to do this would be to weld on two metal bungs onto the tube, and get ceramic or teflon insulators that thread into that, and then install the probes into the insulators. a slightly less complicated way would be like that diagram you posted a few above. that is as "less complicated" as i would go with it though, i would personally never use epoxy in this way.

remember orientation of the tube will matter; you will always want the heater at the bottom so the sensor definately gets triggered before the element becomes unsubmerged. you also want to verify that the controller actually does register the signal change (in resistance- im guessing?) when it goes from being submerged to not being submerged. sometimes in a hot and humid environment, continuity sensors can detect a partial circuit even without being fully submerged, but the exact threshold can be incorrect and it may not register the fault.

you could also use compression fittings (1/8" NPT x 1/4" tube) put 1/4" od plastic tube in and then 1/8" metal probes in, the compression fittign will squeeze the tube and hold and seal the probe.