drawing process heater system level controls

Liquid Level Controls on Every Process Tank

Author: Skip Schaefer

Recently I talked to a customer about his process tank leaking. This is no small tank... no sir. It is 8000 gallons of sodium dichromate. Well this is a 26-foot-long tank x 5' wide x 8' deep. Probably 20+ years old.

At the time of construction, it was 304 or 316 stainless 2” x 6” or 2” x 8” stainless channel lips fully welded around the top intersection of the tank wall and channel. Then the gussets and girths, which were comprised of 6” steel “I” beams, were welded directly to the stainless tank sides. Quite a bit of water volume for an industrial process heater, tall electric heaters were necessary to get into this deep tank.

Leaking Tank Blues

Here we are 20 years later, and the tank is leaking, not at any of the corners but in the bottom center of the tank. I’m speculating that “electricity took the path of least resistance” and that was at the center “I” beam in the center of the floor of the tank.

Now a liquid level control, inconspicuously placed in the corner of the tank, wired to a motorized ball valve, (solenoid valves aren’t as hardy) connected to the main water feed, in the event of low liquid in the tank, would have exposed the probes and shutoff the main water.

Water Level Controls Can:

  • • Prevent tank overflows, (HI-HI, 2 prongs, 1 tube air bubbler) especially on hard chrome tanks among others that run 24/7
  • • Fill and maintain a certain level in the tank like electroless nickel, (3 tube air bubbler)
  • • Use as a low level shut-off (2 prong or 1 tube air bubbler)
  • • Maintain rinse tank levels (3 prong) within a ½ inch
  • • Shut off Hot Water or steam systems feeds, including immersion heaters circuits (before the thermal cutoff is exposed on the heater)

Now solution level probes, sensors, and controls only work depending on the application.

Cheap Insurance

You are thinking… “what is the cost of the level control system, motorized ball valves, electrical, installation costs.  The answer is cheaper than the cost of a cleanup like this.  Cheap insurance. 

Skip Schaefer has been manufacturing metal finishing equipment for 50 years. 
Contact him for further questions or assistance setting up your process heaters and tanks.

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