It’s All about Control

Ask any engineer what the most significant advance in food production systems has been in the last 20 years, and the likely answer will be electronic controls.

Machine tooling that resulted in much tighter tolerances of components was one consequence of NASA space exploration, but barring a new spending spree or major investments in similarly ambitious projects, machine components are about as good as they’re going to get for the foreseeable future.

Control technology, on the other hand, continues to make large leaps forward—specifically the software that drive those controls. I was reminded of this at “How to be a Better Bakery,” a workshop on precision coating and cleaning presented by Spraying Systems Co. Founded 77 years ago in a Chicago garage by two Danish immigrants, the Wheaton, Ill.-based firm makes nozzles, manifolds and other components for spray applications. A sanitary nozzle for food applications is in the inventory, but the hardware can be used to spray paint and herbicide as easily as food coatings and antimicrobials.

Hydraulic nozzles are the preferred solution in food applications, explains Josh DeVoll, director-market solutions, because flow can be more tightly targeted and regulated than with aerosol delivery. Air nozzles also pose housekeeping issues and can create respiratory and slip-and-fall danger for workers. The limiting factor with hydraulics is flow rate: if minute quantities are to be delivered, air nozzles may be the only option.

Development of precision control systems is expanding the applications for hydraulic, however. The firm’s base controller operates at 5,000 cycles per minute, fast enough to deliver 2 grams of a release agent in a bakery application to within 0.1 g of the target, according to DeVoll. If 5 percent giveaway is too much, greater precision is possible with more advanced controls. A top of the line system cycles 15,000 times a minute.

That’s overkill for most sprays, and that level of precision comes at a premium price. But if line speed is high and the liquid being sprayed is costly enough, simple arithmetic will determine the ROI from the higher cost.

In one field application, the spray controller was synced with a high-speed Weber slicing machine’s controls to deliver an antimicrobial to each slice of deli meat as it came off the slicer.

Rapid cycling is only part of the advancement, of course. The ability to adjust the duty cycle for variances in hydraulic pressure, line speed and other variables also is important. System components aren’t changing, but refinements in the control of their performance are and will continue to advance.