Perhaps the cruelest dilemma in food processing during the pandemic has been the impossibility of social distancing.
Keeping at least six feet away from others has been a fundamental safety principle, but the setup of many food & beverage plants doesn’t permit it. As the world begins to emerge from the pandemic, processors must think about whether and how to make arrangements to allow social distancing, should it become necessary again – especially if they’re about to build new or renovate a facility.
Conveyors can play a role, at least in some cases. With current and emerging technologies, conveyor systems can be configured to increase distancing between workstations or otherwise protect workers.
“We’ve had many queries about how conveyors can help maintain distance for employees working in facilities,” says Stacey Johnson, director of marketing and strategic planning at Dorner Manufacturing. “Certainly, everyone has had to adjust the way they produce, manufacture and package food in order to conform to CDC guidelines. Employee safety is now more important than ever before.”
The biggest issue, of course, is space. In many plants, there simply isn’t room to space workers apart.
“In most applications, we are finding the biggest obstacle to overcome is not 'Can we modify our equipment to work,' ” says Chris Woodall, manager of integrator services at Hytrol Conveyor Co. “It’s 'Does the customer have the real estate required to social distance employees properly.' ”
Accessories available from Dorner include a mounting bar that allows for partitions to be installed between workstations.
Barriers to progress
One alternative is to protect them with barriers. Early in the pandemic, processors resorted to makeshift measures such as attaching sheets of Plexiglas perpendicular to conveyor lines to create individual workstations. Perdue Farms at one point had large wire hoops installed that way, which served as frames for clear plastic garbage bags, which were changed between shifts.
Some conveyor suppliers are including barrier installation as an option on equipment. Dorner has, as an accessory for its AquaPruf conveyors, a mounting bar that allows for partitions to be attached directly. Multi-Conveyor also has barrier stations available, especially for hand-packing operations.
“The length of the pack zones, number of conveyors or required side tables are determined by application, working with individual plant safety guidelines,” a Multi-Conveyor spokesperson says. “The barrier-spaced stations can also be implemented into existing work areas with ease.”
End users who want to attach barriers to conveyors must be sure that the conveyors are configured to accommodate them. This means working around motors and gearboxes – or avoiding them altogether.
VDG can accomplish this with drum motors that attach to the end of a conveyor segment, avoiding bulky conventional electric motors and their power transmission equipment that tends to stick out the conveyor’s side – exactly where you don’t want it.
“By saving ‘real estate’ around the conveyor frame, companies can maximize employee workstation areas without having to guard external motors and/or gearboxes,” says Rick Zander, business development manager of VDG. “This is saving processors space, which maximizes workstation utility, allowing for efficiency in employee safety.”
Timing is everything
Even where space exists to establish social distancing, there is still the challenge of timing. Conveyors have to establish a speed that will allow workers enough time to complete their tasks, while maintaining an acceptable throughput.
To some extent this can be done by conventional means. The simplest one is just making the line longer. Others include altering the timing of the line by building in accumulation points and other speedup and slowdown areas.
“With the large portfolio of conveying equipment at Hytrol, modifying it to allow social distancing can easily be done,” Woodall says. “Whether it’s simply lengthening conveyor, adding zoned accumulation between work stations or additional drives, we have a solution.”
But the basic dilemma is that almost all conveyors are designed to run at only one speed. Even when they have the physical capacity to vary speeds, through the use of variable-frequency drives with AC motors, that’s usually done only to accommodate overall shifts in production, not the needs of individual workers. Placing workers farther apart and speeding up the line to get product to them faster won’t really work if they still need to spend the same amount of time working on that product.
Technology is emerging that has the potential to solve that dilemma. It enables what amounts to a beltless conveyor – a system in which products are carried, not by a common belt or chain, but by individual devices that slide around and can be sped up, slowed or stopped at will.
Rockwell Automation has several such “intelligent conveyance” systems. The basic technological innovation behind them is the “linear motor” – a sort of inversion of the conventional motor setup of a rotor and stator. The “cart” – the component that carries the payload – becomes the stator, propelled by electromagnetic interaction as it moves over the track.
Rockwell uses this principle for products including the iTrack, which is made for high-speed, high-acceleration movement of loads up to 80kg; MagnetMotion, which comprises several different product lines for transportation between machines; and the QuickStick, for heavier payloads.
The XPlanar from Beckhoff Automation uses magnetic suspension to carry individual units in two dimensions.
Beckhoff Automation offers similar products in XTS and XPlanar. They use a different form of propulsion: magnetic suspension that “floats” the tiles across a surface, which is linear for XTS, more free-form with XPlanar. According to Beckhoff, XTS is being used in more than 1,600 food & beverage applications globally, while the newer XPlanar has several food apps, including a German schnitzel line.
The potential for beltless conveyors to contribute to distancing workers on lines, while maintaining production speeds, lies in their ability to speed up and slow down individual units as needed.
“It’s a way to take the entire manufacturing process, turn it on its ear and get rid of all the confines we had where conveyors go from point A to point B to point C, and you have a bunch of workers working in one section,” says Mike Wagner, OEM segment manager for Rockwell Automation. “Now you can create branches and you can separate workers out to any distance and change the task and the function if you want.”
Wagner says it would be possible to configure a beltless conveyor so that units move away from one worker and toward the next based on a go/no go signal that could originate with the worker, or with a vision system that can tell when a step in the process is complete.
Social distancing was hard if not impossible to accomplish in most food & beverage plants during the pandemic, simply because there had never before been a need for it, or even the idea that it would ever be necessary. Now that idea has firmly taken root, current and future conveyor technology will play a big role in making it happen.
