The Big Chill
Leading stretchwrapping equipment manufacturer adapts its renowned rugged end-of-line machinery for low-temperature operations
March 24, 2020
The chilly Canadian winters are not to everyone’s taste, but for the Wulftec International Inc. management team, the recent onset of the cold season provided an opportune moment of inspiration to make its high-performance stretchwrapping machinery go well beyond the standard seasonal limitations.
When building material suppliers see their packaging equipment freeze up after being moved to outdoor locations, the bundling of bricks, blocks, and masonry products with standard stretchwrapping machines typically becomes impossible when exposed to arctic conditions.
Similarly, many manufacturers of ice cream and frozen foods often find themselves short-changed when trying to perform routine end-of-line packaging operations in below-zero warehouse environments to achieve better quality and productivity.
With such applications requiring stretchwrapping equipment that could stand up to frigid temperatures, Wulftec believed there was an emerging market niche for a system that could operate efficiently in -30°C to 70°C temperatures.
But developing this equipment would require surmounting considerable technical challenges.
As a long-time leading provider of robust end-of-line packaging solutions, Ayer’s Cliff, Que.-based Wulftec patiently built up its brand by offering equipment with heavy-duty construction to withstand the rigors of rugged industrial and outdoor environments.
Designed and fabricated for customers across a wide range of food, beverage, printing, building products, and metal coil applications, Wulftec machines are renowned for their use of non-proprietary components that simplify the end-users’ maintenance requirements.
With its corporate motto proclaiming “We Fear No Packaging Challenge,” Wulftec fully embraced the idea of opening up this potential new market niche, but as the technical challenges of cold-weather operation were carefully evaluated, some critical design issues, mostly involving the machinery’s pneumatic components, started mounting up.
- Low-temperature pneumatic components: Conventional pneumatic components were not designed to withstand -30°C temperatures. Special seals, O-rings, and solenoids would be required for freezing environments.
- Air supply quality: Humidity in the compressed air supply rapidly turns to ice when subjected to arctic conditions, which can harm pneumatic valves and cylinders and potentially stop machine operation. Knowledge of the customer’s compressed air quality would prove critical to solving the low-temperature air-drying problem.
- Bearing and gear box lubrication: When starting the machine after downtime, frozen components may not perform properly due to lubrication issues.
Bearings and gear boxes would require reengineering, modification, or heating elements to work efficiently in low temperatures.
Overcoming these technical challenges would be vital to creating a dependable packaging system that could withstand below-zero temperatures.
Wulftec leveraged the expertise of its supply base to help resolve the issues surrounding cold-weather operation.
Emerson’s ASCO Numatics pneumatic products had been incorporated in Wulftec’s equipment for almost 30 years, and the companies had forged a close relationship.
Emerson technical specialists helped Wulftec’s design team identify the pneumatic products that would need upgrading to meet the application’s extreme conditions.
These included directional control valves and manifolds, aluminum-body cylinders, bellows, slides, and air-preparation equipment with dump valves.
Wulftec’s equipment design called for pneumatic components based on NFPA standards.
The ASCO Numatics NFPA product line simplified component selection and made installation and assembly easier.
While the ASCO Numatics brand comprised the industry’s broadest range of -35°C-rated components, additional engineering work was necessary to certify the pneumatic system for sub-zero operation.
The Wulftec-Emerson team identified low-temperature switches for position sensing and spool detection.
An ASCO Numatics pilot valve that was ATEX-rated to -40°C was added and the assembly was tested successfully at -30°C.
The stretchwrapping machine’s first design called for a filter, regulator, and lubricator (FRL) with two low-temperature dump valves with quick-exhaust, soft-start capabilities.
But this solution did not have the needed airflow and was too expensive.
Emerson recommended a higher-flow FlexiBlok FRL with a single, dual-redundancy dump valve to lower the cost.
However, the standard FlexiBlok components did not have -30°C certification.
The solution: install a FlexiBlok slow-start assembly with a -40°C-rated regulator, plus another component rated at -32° C.
The components were joined with a ring seal and tested to prove they could withstand low-temperature operation.
Engineering work also was needed on the FRL’s dump valve.
While the product’s body was rated at -40°C, the solenoid was not.
Emerson identified an ASCO Numatics solenoid in Europe that fulfilled the specifications.
The solenoid was mated to the valve body with cold-weather O-rings and testing confirmed the modified device could function reliably in sub-zero environments.
One additional step: the ASCO Numatics cylinders were modified with low-temperature seals to add durability in cold-weather conditions.
To determine the compressed air-quality standards needed for the new machine, Wulftec turned to its user base.
Customers agreed that humid air entering the pneumatic system would be a problem in freezing temperatures.
Emerson’s technical experts recommended more robust air-drying equipment that could eliminate the operating problems associated with harsh environments.
Once the appropriate components were selected, Wulftec and Emerson tested the entire pneumatic system at -40°C to ensure reliable low-temperature operation.
The other components most vulnerable to below-zero conditions were the machine’s bearings and gearboxes.
Working with its suppliers, Wulftec discovered that most of these products were available with low-temperature ratings.
However, some devices required heating elements to warm the lubrication for normal start-up and operation.
By conquering these issues, Wulftec introduced the industry’s first line of low-temperature stretchwrapping systems and has sustained its leadership in this growing niche market.
Greater customer satisfaction and product innovation are key parts of Wulftec’s continuous improvement journey.
The low-temperature stretchwrapping equipment has evolved with the market as stretch film becomes thinner and higher performing.
At -30°C, the film becomes brittle and more difficult to process.
Wulftec has modified the low-temperature line to effectively manage these new materials.
Wulftec also has called on Emerson’s expertise for pneumatic system enhancements.
With modular construction, higher flow, and a low-temperature dump valve, applying the ASCO Numatics Series 652 FRL to the stretchwrapping machine helped lower operating and maintenance costs while enhancing system flexibility.