Pacepacker makes light work of heavy potato sacks

The potato-packing company grows arable crops, fruit and vegetables for retailers and food service providers. The company operates two potato-packing facilities and at both sites, potatoes are packed into 1-5kg retail-sized polybags and then outer sacks - the preferred method for containment and display at many local shops, green grocers and convenience stores.

Several years ago, the food retailer - a major customer - approached the potato-packing company requesting that potatoes destined for their distribution centres be supplied in smaller 12kg sacks instead of the larger 25kg sacks historically produced. Paul Wilkinson, Pacepacker's Business Development Manager explains: "The food retailer wanted to switch to 12kg sacks for their smaller stores, on the basis that they would be easier to handle, occupy less space in store and keep the product fresher."

The potato-packing company's existing collator wasn't versatile enough to cope with different sack sizes, so the smaller-sized packs at that point were being hand-packed. Paul reflects: "It is generally more efficient and safer to automate repetitive tasks that involve heavy manual handling. However, in the absence of a mechanical solution, the company coped by allocating two people to pack and stitch the smaller sacks by hand. Despite this resource, they struggled to complete the task fast enough, as the necks of the sacks have very small openings, which makes them awkward to open and fill by hand."

Aware that this situation was unsustainable, the company began to investigate a more flexible replacement for its collator. The search was not easy, primarily because few equipment engineering companies are willing to tackle such a specialist application involving a challenging product. Paul notes: "Potatoes are not easy to work with. The force with which they are discharged into sacks when the trap doors open can damage machinery, especially the stretch bars that hold sacks open. What's more potatoes can bruise easily causing product waste."

A flexible system

With a reputation for thoughtful engineering and robustly constructed packaging equipment, Essex-based Pacepacker Services rose to the challenge. The multi-award winning packaging equipment manufacturer designed a more flexible collation system that quickly collates and places pre-packed bags of potatoes ranging from 12-25kg in size into outer sacks.

In engineering this collator, Pacepacker was mindful of the mistakes made by other manufacturers of this type of kit. Paul explains: "Many systems on the market don't control the fall of the product very well, which often results in pre-packs breaking through the bottom of the outer sack due to their weight and density. We improved this phase of the process by incorporating motorised support arms to control the descent of the polybags into the outer sack, eliminating damage and waste to both product and pack."

Pacepacker also addressed the potential issue of bags breaking the sack stretch bars by programming the holding doors to open gently and release the bags more slowly.

Now at one of the potato-packaging company's sites, potatoes are packaged on a form fill seal machine, conveyed over a checkweigher, and presented to an inclined elevator, which transports the packs up to the holding doors of the collator system, at speeds of 48 packs per minute.

Pacepacker's collator then uses pre-programmed operating software to select the number of bags required - usually either eight or 16, pauses the conveyor, and opens the holding doors, allowing the bags to gently drop into an accumulation chamber and then into the outer sack waiting below. As the bags are released from the chamber to the sack, motorised arms control the descent accurately, smoothly and with minimal moving parts. The system can store multiple product recipes to accommodate numerous multi-pack product variations, either by weight or amount.

3000 polybags of potatoes

The machine is operational 6 days a week for two 8-hour shifts per day, packing on average 3000 polybags of potatoes each shift. An engineering manager from the potato-packing company explains: "Some days it is packing larger sacks, on other days smaller ones, depending on what our customers order. That is why the flexibility is so important to us."

Following this collator installation, the company reduced the number of operators on the line from three to one - an operative still stacks the sacks onto pallets. As testimony to the project's success, a year later they purchased another Pacepacker collator for its second site.

The engineering manager concludes: "Pacepacker supplied a machine that provides the level of versatility that would usually require two separate collators. Its ability to handle the smaller sacks has enabled us to meet the requirements of the Co-op's distribution centre and reduce staffing on the line. Essentially, the collator paid for itself through labour savings within 12 months of installation."

Go to www.pacepacker.com for further details about Pacepacker's products and services, including collator systems.