Radar Level Measurement Improves Inventory Control for Citrus Processor

  At Emerson Exchange, presentations involving everyday household products usually draw good attendance. Anything related to beer is a sure-thing, but so was a presentation about manufacturing orange juice. The session presenters told their story again in an article discussing a major operational problem and the solution the company found to overcome it.

 The company, Southern Gardens Citrus in Clewiston, Fla., was wasting labor time taking inventory readings manually. The full story is told in the June 2019, issue of Processing, Radar Level Measurement Improves Inventory Control for Citrus Processor, by Joe McDaniel and Don Parry. The authors lay out the challenge of determining how much freshly made orange juice concentrate has been transferred to a tank for freezing.

 Storing the concentrate takes place in a special building within the facility where 16 tanks stand close together connected by catwalks. Each tank is 32 feet in diameter by 32 feet tall with a capacity of 186,514 gallons. The building is a huge freezer. Florida is known for its heat and humidity, but the temperature inside this building is a frigid 16 °F (-9 °C), with a lot of internal air movement. Maintaining this environment allows the product to cool rapidly in the tanks, with no internal cooling coils or jackets required.

Production of concentrate at the plant is constant so inventory is moving all the time. Some tanks are being filled while others that have cooled completely are emptied. The problem was keeping track of what was in each tank.

                    Operators had to check the tank levels on a daily basis by hand, using manual measuring devices. While the idea of going inside a freezer on a hot day in south Florida might have some appeal, the novelty wears off quickly when it takes up to 30 minutes to check just one tank while working in the bone-chilling temperatures. Checking 16 tanks daily required eight hours, so the plant spent as much as 56 man-hours per week on nothing but checking inventory in these concentrate tanks.                       

 Southern Gardens’ engineers wanted to try another level measurement solution, but after the initial failure of ultrasonic level instruments, they were skeptical. Don Parry, Emerson’s local representative, suggested the Rosemount 5400 Level Transmitter – Non-Contacting Radar, since each instrument could be installed in the same mounting spuds and use the same wiring as the earlier ultrasonic units.

The temperature wasn’t a problem, but there was concern about foam forming when the still warm concentrate was first moved into the chilling tanks.                                    

                     There can be a layer of foam on top that forms during filling and tends to freeze. The foam surface is capable of reflecting the radar pulse, causing the instrument to deliver a false reading. However, if the pulse is strong enough, the actual liquid surface can send a second reflection, and the measuring software can capture it as the true reading. The suggested non-contact radar level measurement instrument uses an approach called dual-port technology, which creates a stronger radar pulse for just this type of multiple echo application.

 The test installation was a success and new Rosemount radar transmitters were installed on all 16 tanks. The most obvious benefit was doing away with manual measurements, but the company also realized many production and inventory management gains from having continuous level data on every tank, rather than just one reading per day.

You can find more information like this and meet with other people looking at the same kinds of situations in the Emerson Exchange365 community. It’s a place where you can communicate and exchange information with experts and peers in all sorts of industries around the world. Look for the Level Group and other specialty areas for suggestions and answers.