We have a slowly rotating (10 rpm) cylindrical vessel (18" dia X 40" h) in which we wish to measure and control the level of a hot steaming (200 degF) liquid. Because of mechanical constraints, we cannot access the top of the vessel. The lower sides of the vessel also have very limited space available (aprox 1.75" x 2.0"). The bottom is also not accessible.

Most of the wireless offerings today are too bulky to fit into the limited space available on the lower sides....and.... As the machine is only used once or twice a week, battery life could only be extended if there was an easy way to turn the device off. Most do not have this feature.

I am wondering if anyone has seen any compact pressure sensors that are combined with appropriate RFID technology which could be used as a possible solution. Any other suggestions?

Yikes...Almost forgot...it's all in a washdown environment.

Thanks in advance for your feedback

Cheers
Gerald Beaudoin

 

Since your process is hot could you disable the transmitter when it's cold e.g. < 100 degrees?

 

Hi there,

I suggest you investigate if control of the flow inlet/outlet might not be a better alternative to level control in this case.

Another possibility might be to control the weight of the complete tank or installation with a load cell or three. You can Tare the tank weight out from the Gross weight and get a Net weight of the liquid inside. Convert that to volume then to level and you can still get a pretty accurate level indication by making use of a loadcell. (1 Liter of clean water = 1 Kg, volume of inside of tank = so many liters, volume has a direct relation to level in a symmetrical vessel and so on, quite easy to do these conversions in the PLC/DCS/SCADA)

Weight control could be a good alternative to level control in applications where the level cannot accurately be measured and controlled.

 

Thanks guys for the suggestions....may well take a closer look at load cells and go for the weight/volume/level approach.

Cheers

Gerald

 

Hi Mr. Beaudoin,

Here is a very small rf module which may meet your application. Its size is about 28mm×15mm×10mm. A transmitter and a receiver can do wireless communication. Please check

http://www.rf-data.com/ProductShow.asp?ID=106

Or any questions, contact me at sales02 at rf-data.com

Cheers,
Sunny