The food industry races to get products from farm to processor to market as quickly as possible, but how fast it moves off the grocery shelf and into a shopping cart depends on the whim of the consumer. That’s why packagers increasingly embrace modified atmosphere packaging (MAP).

Every food product has its own ideal atmosphere, be it oxygen, nitrogen, carbon dioxide, or a carefully controlled mixture of gases. MAP lets processors and packers adjust the atmosphere within a package, preserving freshness, ensuring safety, and extending the shelf life of meats, vegetables, and other items that go bad over time.

New design

One of the latest offerings from UltraSource, Kansas City, Mo., is the Rhino 12 high-capacity modified-atmosphere tray-packing machine that’s specifically built for washdown environments. It’s designed for medium to large-sized commercial production and accommodates bowls, trays, and family packs. For example, the Rhino 12’s extra-wide seal area simultaneously handles up to four rows of popular #3-sized trays.

Machine throughput rates are up to:

  •  7 cycles/min for vacuum/gas mode.
  • 8.5 cycles/min for gas-flush mode.
  • 10 cycles/min for seal-only mode.

A stepper motor advances trays with ±0.5-mm repeatability into the sealing mold, where they’re sealed with plastic film and then automatically discharged. But because the unit must stand up to the heat, chemicals, and high pressures common to washdown environments, much of the motion control and actuation depends on pneumatics.

Pneumatic motion

“Contaminants and moisture can have a significant negative impact on the performance and energy efficiency of pneumatic-based motion actuation in washdown environments,” says Scott Lickteig, a machine design engineer at UltraSource. For that reason, the company worked closely with engineers at Festo, Hauppauge, N.Y., to specify pneumatic components that would set the Rhino 12 apart from its competitors in terms of uptime and performance for this class of high-capacity machine.

Among the pneumatic motion-control functions, the Rhino 12 uses Festo DNC-80-175 cylinders for die closing, AEVC-25-10 cylinders for film clamping, and ADN-80-30 cylinders for sealing and cutting.

The DNC cylinders in this application have an 80-mm diameter and 175-mm stroke. They are standard, double-acting cylinders made of aluminum alloy with a smooth-anodized finish, and high-alloy steel piston rods. They come with polyurethane or nitrile-rubber seals, although fluoropolymer seals are available. Ambient temperature rating for the standard version is –20° to 80°C, though optional versions handle temperatures from –40 to 120°C.

AEVC cylinders are compact, short-stroke, single-acting units that come in diameters from 4 to 100 mm with strokes from 2.5 to 25 mm. The version used here has a 25-mm diameter and 10-mm stroke. They’re designed to offer rapid response, large clamping force in relation to their size, and require minimal installation space. They have anodized aluminum bodies, alloy steel rods, and polyurethane rod seals.

The ADN products are compact, double-acting cylinders. The Rhino 12 uses versions with 80-mm diameter and 30-mm stroke, but these cylinders are noted for availability in a wide range of variants, configurations, and mounting accessories — thanks to its modular design — letting engineers tailor them to suit specific applications.

They feature anodized-aluminum construction, alloy-steel rods, and polyurethane or fluoroelastomer seals. Standard, built-in cushioning rings absorb impact energy and, thus, permit high speeds, fast machine cycles, and long service life.

Controls

Controlling all the machine’s pneumatic valves is Festo’s VTUB electronically controlled valve manifold. It can hold from two to 16 valves on a single manifold, making it suitable for a wide range of pneumatic applications. Valve options include 3/2-way normally open and normally closed; and 4/2-way valves with single or double solenoids. It also handles vacuum applications. Pressure capabilities range from –0.9 to 8 bar and flows to 1,000 lpm, and operating voltage ranges from 12 Vdc to 230 Vac. This compact manifold also saves on wiring — the VTUB requires only a single cable with a 26-pin connector to control and activate the manifold’s nested valves.

Festo also offers a valve-terminal configurator to help users more easily select the right version for an application. All terminals are supplied fully assembled and individually tested, reducing installation time for the machine builder.

A Festo D Series air-preparation unit filters, regulates, and lubricates the Rhino 12’s compressed air. Supplying clean and regulated compressed air to a pneumatic system helps ensure better overall performance and energy efficiency over time, compared with a system operating on dirty, unregulated air. Both the D Series FRL and VTUB manifold are mounted in a NEMA-4 rated enclosure. A Festo CRVZ-10 compressed air reserve tank rounds out the core pneumatic system.

“Over the course of its lifetime, Rhino 12s will perform millions of cycles and UltraSource wanted a trouble-free, reliable, and accurate motion system that customers can depend upon,” said Kevin Ost, Festo Food and Beverage Industry Segment sales engineer. “The care that went into the pneumatic system design was exemplary and the result well suited to the application.”

Other features of the Rhino 12 include a controlled film-advance system that reduces film breakage to near zero and tightly controls advance distance from the uncut side for optimum conservation of film. Its proprietary film-clamping system provides assured sealing. And a pivoting discharge conveyor provides for easier maintenance access to the inside of the sealing area than most if not all high-capacity tray packers. Product changeovers take less than 15 min, as users need to change only a single tool.

The Rhino 12 includes an 8.3-cfm, 10-hp compressor, and a 7.5-hp vacuum pump. Optional features include a motorized ejection conveyor, printed film registration, integrated film labeler, 10-hp vacuum pump, and additional lane configurations.

For more information on UltraSource food-processing and packaging equipment, visit www.ultrasourceusa.com. For more information on Festo pneumatic components and systems, visit www.festo.com/us.