Pneumatic actuation is ubiquitous in food and beverage-processing equipment because it outperforms electric automation for many tasks. Pneumatics have a lower upfront cost and higher resistance to harsh cleaning — both dry and wet. With minimal electrical or electronic subcomponents at pneumatic axes’ end effectors and points of application interactions, these delicate elements aren’t potential points of failure as they are with designs based on electric motors.
In fact, another reason pneumatics are more economical for many food and beverage operations is that they avoid the costly housings, seals, and isolating shields that electrical or electronic subcomponents need — especially when subject to washdown. If a pneumatic design prematurely fails in a processing setting due to an exceptionally harsh environment, replacement isn’t expensive.
There are some caveats: Design engineers should eschew all-purpose pneumatic cylinders for those specifically designed for washdown settings. Such washdown-ready pneumatic cylinders have (among other things) large housing radii that don’t hinder high-velocity disinfectant sprays. Typically, these smooth cranny-free surfaces also feature high-gloss finishes that provide no harbor for microbial growth … satisfying Current Good Manufacturing Practices (CGMP) regulations. Here, IP69K machine-mountable valve manifolds can contribute to the smooth easy-clean build of machines subject to frequent cleaning.
Pneumatic air supply and exhaust considerations
Shortening manifold-to-cylinder tubing runs dramatically reduces assembly complexity and cost. Such arrangements also boost design efficiency as well as machine speeds and other dynamics. That’s especially important for helping meet the high-throughput requirements of beverage and food operations needing consistent products with minimal waste. Some manifold supply and exhaust port arrays can also allow for completely independent control of multiple valves — especially useful in food-processing equipment having various pressure zones.
No matter the manifold arrangement, it’s essential that valves never be exhausted into food. That’s because such air has come through a compressor, onwards to a valve and cylinder, and then back out … so likely has collected contaminants. Instead, valves (including check valves) should mount to the undercarriage of equipment or (if mounting from above is best for other reasons) ducting should lead the air down and out.
Further addressing this compressed-air issue in 2021, the Global Food Safety Institute-recognized industry-standards organization Safe Quality Food Institute included in its SQF Code 9 edition a section on air quality stating that compressed air used in the manufacturing process must be clean … and present no risk to food safety. The guideline was included because compressed air is often in direct or indirect contact with food products, and contaminants in compressed air can cause changes in color and taste, reduced shelf life, and product recalls. Fortunately, new compressed-air microbial detection devices let personnel take samples faster and easier without the need for extensive training.
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Filed Under: Pneumatic equipment + components, Food + beverage