Pneumatic Control: The Softer Option for Food and Beverage Packaging
For years, food and beverage packaging OEMs have trusted pneumatic power for its cost-effective simplicity in packaging applications, as it's affordable, dependable, and highly productive.
But one of its most notable features is its singular ability to move breakable, fragile, and variable items with a yielding, gentle touch.
This is something its two main competitors in the field, hydraulics and electromagnetics, cannot always do well for the price: The reason is that compressed air, by its nature, is a responsive, compressible force.
"I don't know of anything more cost-efficient than pneumatics, compared to hydraulics or electromechanical actuators," observes Dan Davis, product sales manager for Parker Hannifin’s Quick Couplings Division. "It's extremely cost-effective to provide the control."
The discussion below provides details on why pneumatics provides the perfect amount and type of force in food and beverage packaging applications.
A Compressible Mode of Force
Both pneumatic and hydraulic power are considered fluid power for motion control, however they differ in their responsiveness. Hydraulic fluid, which forms the basis of hydraulic power, is an incompressible, solid media that cannot be compressed further should it meet resistance. However, compressed air, which drives pneumatic power, can be compressed.
"There is a softness of grip and a softness of touch in the motion that can be controlled or defined very easily through pressure regulation," Davis explains.
This yielding mode of power is beneficial to packaging applications, where product integrity could be compromised by excessive force.
Take, for example, the process of filling and moving two-liter beverage bottles, where several are gathered before being pushed into a paperboard container.
If the movement is controlled with hydraulic cylinders, and the bottles become jammed in the process, the brute force of the hydraulics is likely to rupture them. This wastes hydraulic power and leads to product spillage, equipment downtime, and decreased productivity.
Electromagnetically powered cylinders may have similar results, such as forced movement, overheated equipment, wasted energy, and the risk of electrical shock should a liquid-filled container burst.
Pneumatically powered controls, on the other hand, are less likely to break products should they encounter a jam. If the process hangs or sticks, the amount of force applied will regulate and stop, often without causing undue strain and without continued consumption of compressed air.
Power That Can Be Regulated
Pneumatic power also is adjustable for individual tasks, another important benefit when gentle handling is desired. Even though compressed air pressure within a global airline system typically remains constant, the level of force can be regulated at individual operations. This means that the pneumatic force applied to pack six bottles into a carton can differ from the force applied downstream to move that case of six-packs onto a pallet. Simple pressure regulators on valves at these operations allow this to happen
Davis points out that this variable pressure control is especially beneficial when moving highly variable objects, like apples, which differ in size, texture, and weight. Not only do different sized products require different amounts of motive power, they also have differing abilities to withstand motive forces. Besides conserving compressed air use within the system, pressure regulation also helps ensure that fragile products like pieces of produce or bags of potato chips maintain their integrity.
The ability to regulate pressure is unique to pneumatics at this price point, Davis points out. Competitively priced hydraulic and electromagnetic systems generally are limited to one or two pressures for all operations.
An additional benefit is that processors can adjust operational forces based on seasonal or supplier-based size and shape differences in products. Considering that fruits and vegetables vary from season to season, from supplier to supplier, and even from day to day, there’s no question that having the ability to customize motive power when necessary leads to more consistent results.
In these ways, pneumatic power lends itself to operations where gentle handling of products is required. This responsive, compressible form of motive power preserves product integrity, conserves compressed air, and is easy to adjust as packaging needs demand.