Food laboratory technicians charged with cleaning sieves used to inspect raw materials for correct grain size may welcome a specially designed ultrasonic cleaner developed by acoustic R&D engineers at Elma Ultrasonic in collaboration with food lab personnel at two locations.
The result of this collaboration is the Elma S50R ultrasonic cleaner available from Tovatech. It is optimized for sieve cleaning, but also for degassing HPLC solvents and for sample preparation involving difficult-to-dissolve substances. A unique feature of the S50R is its built-in programming: food scientists can select three programs by pressing the corresponding key on the cleaner’s control panel: sieve cleaning, degassing and sample prep. There is also an on-off key for standard cleaning and a timer showing set and remaining time.
Sieve Cleaning Challenges Solved
While ultrasonic cleaning is safer and gentler than using brushes to dislodge particles trapped in lab sieves thoroughness has been a problem due to “dead zones.” These are areas of low or no ultrasonic cavitation. Typically the zones are found above cleaning tank drains or when regions of low cavitation called standing waves in the bath coincide with the sieve level.
Elma researchers solved the first issue by designing a round cleaning tank without a drain. This provides equal ultrasound distribution against the sieve mesh. The standing wave issue was solved by incorporating a sweep mode to provide homogenous distribution of ultrasonic cavitation throughout the cleaning solution. Both approaches eliminate zones of low cleaning performance.
Particle removal, whether insoluble or soluble, is achieved by automatically alternating between a high-intensity pulse mode for insoluble particles and the uniform sweep mode for soluble and water swollen particles.
The S50R design has proven highly effective in cleaning 100- and 200-mm lab sieves and 200-mm sieves with transponders.
Degassing whether for HPLC solvents or for preparing fresh ultrasonic cleaning solutions is accomplished by operating the cleaner in an on-off mode that causes air bubbles to form, rise and burst. If the off phase is too short the bubbles may not rise and burst but instead remain suspended. This issue was solved by incorporating a special frequency modulation program activated by selecting the “degas” key to actively lift out gas bubbles.
The S50R food lab ultrasonic cleaner is fitted to accept an optional laboratory stand and clamp to hold flasks and solvent bottles at the correct position in a water bath with a surfactant.
Dissolving difficult samples and performing chemical extraction in a fast and safe manner is accomplished by using the unit’s “sample prep” key. Processing can take place in glass beakers fitted into a special cover or by suspending them at least one cm in a water bath. The sample prep key can also be used for routine instrument cleaning in an ultrasonic cleaning solution using the unit’s optional stainless steel mesh basket.
The Elmasonic S50R food lab ultrasonic cleaner has inside dimensions of 9.4″ (diam.) x 5.1″ (height) with a maximum capacity of approximately 1.5 gallons. Other optional accessories include holders for 200 mm (8 inch) and 100 mm (4 inch) diameter sieves.
Contact the scientists at Tovatech for more information on the Elma S50R ultrasonic cleaner or for answers and recommendations regarding other ultrasonic cleaning operations.