Wanted: Liquid Level Sensor Designed for Chemicals

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Saskwa How about thinking outside the tank? Install a weigh pad in each leg of the tank and use the weight of the tank to determine fill level. Jerrell

Try calling Matt Sims at the Cutler-Hammer (Eaton) Sensors Factory in Woodinville, WA. Contact #425-513-5387, Cell 425-876-0826. If Matt can not supply you with your needs, I'm sure he will have a referral for you.

I have some water level sensors on fire trucks that have a sealed stainless steel tube with a series of reed switches inside. On the outside are closed cell foam round hollow floats with magnetics in them. There are snap rings on the outer tube to limit the travel on the tube. Each float can only move about 3/4". If this same float assembly was constructed with SS floats instead, it should work for you. If you want further info, you will have to wait till Monday, at work.

We use pressure sensors, separated from the chemicals via a stainless steel diaphragm. The pressure measures the head in the tank and this pressure is then converted to a level. We use this system for Hypochloric acid, Sodium Bisulphite and others. All our sensors are either Endress + Hauser or Rosemount.

In these installations, it's useful to have a valve separating the sensor from the tank so it can be isolated if repairs are needed.

Hope this helps

Have you thought about using and ultrasonic or laser based sensor?

Quite. PTFE-coated ultrasonic would be a good bet.

Good morning, Jim,

What kind of information are you needing from the sensor? Are you wanting to see what the level is at any point in time, or only when it reaches a specific point (Typically these would be Empty, Low, Medium, High, Overfill?)

What kind of container is being used? I would assume a resistant type of plastic material but they do make metal containers with a plastic liner. Whatever it is, you'll need a sensor that can work in that environment. For instance, there are ultrasonic sensors that can be mounted outside the tank and 'see' through the wall of a plastic tank but don't work so well through metal tanks.

Thanks,

Logan

Hi Logan, We would be reading the levels at specific points. The tank is a heated quartz bath, so reading through the wall is out. Also we are limited to the space

that is available. We are looking at some teflon floats at the moment but the smallest we can find are a 1" dia. float. Would prefer something even smaller.

Thanks for your input. Jim

MC Products manufactures custom tank level sensors for fire equipment. They have 4 and 5 light designs. They use a SS tube with SS rods inside of it. It conducts a small current through the SS rods to trip the lights. The OD of the tube is 7/8". You can reach them at 18008436465. They are located in Hauppague NY. Good luck.

I found their web site. It is http://www.mcproducts.com/

Jim:

Please see http://www.consiliumus.com/Chemical_Gauging.htm

Metritape sensors: The packaged system consists of the Metritape sensor, with either a Hastelloy C276 or an FEP Teflon jacket, compact filter assembly, a sensor housing and a two-wire 4-20mA current transmitter.

I know these sensors have been installed to measure Caustic Soda (Sodium Hydroxide 50%) level.You will have to ask Consilium if sensors are able to be used in Hydrofluoric acid and Hydrochloric acid.

Best regards

Jim,

If all you need is a go/no go indicator for the different levels, World Magnetics and other manufacturers carry small backpressure sensors that might do what you want when used with teflon tubing. Check with them and see what they can recommend.

Good luck,

Logan

Hi Logan, We are using a back pressure stlye sensor now and the N2 is causing a problem with the final product. The bubbles are agitating the chemical and this is

causing defects in the product.

We are using 1/4" teflon tubing at the moment for the sensing tube, but wondering if we dropped down to 1/8" teflon tube if this would dampen the agitation in the bath.

The only thing about this is would be the smaller ID of 1/8" tubing causing enough back pressure to give us false readings.

Now we are looking at an all teflon float, a little bigger than we wanted but may be able to make it work. Thanks for all you input, Jim