Constant-Heat Bars Now Available in Vacuum Chambers

David Vaczek

Multivac has customized its C 500 double-chamber vacuum chamber system (pictured above), and its C 400 model, with solid seal bars for medical product manufacturers seeking easier seal validation.

Meeting an industry demand for an alternative for heat-sealing vacuum-evacuated pouches, Multivac (Kansas City, MO) and Sencorp (Hyannis, MA) are offering vacuum-chamber machines with constant-heat sealing.

Device makers have looked for constant-heat sealing capability in vacuum machines for some time. Some users find constant-heat seal bars easy to validate.

Multivac designed its new medical chamber machines to the specifications of major medical device makers that require high-barrier sealing for medical packages. The company has integrated the solid-seal-bar technology into its C 500 double-chamber system. It also plans to integrate it into its C 400 single-chamber unit, says Bill Williams, product manager, compact packaging systems group, Multivac.

“It took several years to meld 40 years of tray-sealing and rollstock technology into the design of this machine. Multivac has made this investment because we believe there is a market for solid-seal-bar chamber machines,” Williams says.

Sencorp is featuring constant- heat sealing in the first vacuum- chamber-style machine it has offered to the market. For vacuum and gas flushing requirements, Sencorp has provided snorkel-style systems such as its P-Series.

The 12-DDS/2 Deep Draw Vacuum Chamber Constant Heat Bar Sealer features a top-loaded door with a window, gas flush capability, and PLC control with an LCD touch screen. The unit will be commercially available in June, says Kent Hevenor, sales manager, CeraTek, Sencorp.

Sencorp developed the machine for a customer making a drug-coated medical device that is sensitive to oxygen. “Our customer required 12 millibars of vacuum (achievable at sea level). We had to incorporate larger vacuum pumps than what is traditionally used in chamber-style sealers and engineer a more-rugged, thicker-walled chamber,” he says.

Constant-heat systems have previously not been attempted in vacuum-chamber units because of safety issues. Operators are exposed to the heated bar, and metal hoods can reach high temperatures in production cycles. Constant-heat sealing in a chamber machine presented “a huge safety hurdle,” Williams says.

Multivac’s solution includes metal-lid insulative elements. Sencorp’s unit features a mechanism that loads and aligns the pouch in order to keep the operator at a safe distance from guarded bars.

The Multivac chamber machine features medical-grade thermocouples and Beckoff IPC controllers that will also be standard on its rollstock machines and tray sealers this year. The touch screen display with pivoting arm is Web-terminal-capable for downloading production run data.

The chamber unit features “the same constant-heat technology we use in our rollstock and tray sealer machines. We have tested this on every conceivable material for commercial, industrial, and medical use. We create a peel strength that is better than the packaging’s factory-welded seals,” says Williams.

“For low residual oxygen, we can pull a vacuum down to 4 millibars. Then you can gas flush with medical-grade nitrogen” for packaging delicate instruments or where modified-atmospheric packaging is required, says Williams.

Hevenor notes that achieving consistent temperatures with impulse sealing has been a concern with some customers. “It is much harder to deliver a repeatable temperature cycle with an impulse sealer. Your seal quality can change dramatically (in later cycles),” he says.

“We have not had complaints from customers using our vacuum-chamber machines with impulse sealing,” says Michael Lynch, director of sales, Multivac.

“People in the medical device field can build a validation program around a Multivac machine using impulse sealing technology. But right now, there is no controversy around validating constant-heat sealers, and impulse sealing is controversial,” he says.