Keep on moving

27 October 2009



Lynda Searby looks at how developments in conveying systems for packaging applications are helping companies to transport products more efficiently


Conveyors are the taxis of production and packaging lines. It is their job to deliver product to its destination intact and on time, avoiding bumps, jolts, pile-ups and accidents along the way.

In the motoring world, a Ferrari might be the fastest way of travelling, but it may not be the best way unless you’re on an empty autobahn. On extreme terrain, a Land Rover would be a more appropriate choice of vehicle, whilst in a busy city, a nippy Smart car might be the best way of getting you where you want to go.

Likewise, in the world of conveying, the fastest isn’t always the best way of transporting product from A to B. When considering how efficiently a conveyor will carry out a task, factors other than speed come into play, such as whether the system is compact enough or heavy duty enough, how reliable it is and how long it will take to change between pack sizes.

In plants where floor space is restricted, spiral conveyors - the conveying equivalent of the Smart car - provide vertical transfer of product on a tiny footprint. According to Roger Pendleton, of Astec Conveyors, they offer a number of benefits over lifts, elevators and traditional incline conveyors: conveyors:

“As these conveyors can handle a variety of load types and sizes, there is minimal to no time required for stopping the line for change-over or adjustment, which contributes to maintaining a high throughput. Lifts and elevators simply do not offer such productivity enhancements, and are often more complex to operate, which translates into reduced reliability and higher maintenance and energy costs.”

Astec’s slat bed spiral conveyors can transport products ranging from small, lightweight cans and bottles, to cartons, trays, tote boxes, shrink wrapped products and sacks weighing up to 50kg, up or down, at speeds of up to 50m/min. The company says its low friction chain slat arrangement and high quality components assure low maintenance and long life.

Swedish company FlexLink is also an advocate of the spiral conveyor, following the launch of a new spiral elevator in June. “The spiral elevator is an efficient solution for elevating and lowering products in a continuous flow,” says corporate communications manager Klas Ålander. “You don’t get any stop losses on your line and product handling is very gentle.”

FlexLink’s spiral elevator allows transport of goods up or down in manufacturing and packaging lines or between the line and warehousing area. The chain is a patented design, which is said to offer smooth transport, low noise and a high mean time between failures (MTBF).

Bosch Rexroth’s answer to space problems, meanwhile, is the VarioFlow plastics chain conveyor. Unlike the FlexLink and Astec conveyors, it isn’t spiral in design – although its modular design and directional flexibility mean in theory it could be. “It can cut really complex shapes and change angles very easily – all with the same drive,” explains the company’s Mark Dash.

“Plus, because the chain is flexible and plastics, you can not only bend it horizontally, and go round 90 or 180 degree bends within a very small radius, but you can also bend it vertically, so you can go up hill and down dale. This has major benefits when moving products between machines in factories where there is limited space.”

Most recently, the company has expanded its VarioFlow range with the addition of a wedge conveyor. Between two parallel conveyors, flexible clea chains clamp the item being conveyed and secure it during vertical transport from one level to the next.

Space saving was of the essence when Cobalt Conveyors recently supplied two machines to Marlow Foods. The UK Quorn producer wanted two food grade, stainless steel, belt conveyors to link existing equipment, making its meat alternative packing line more efficient. One of the conveyors supplied was a standard belt conveyor, but Cobalt Conveyors had to design the other to be a quick releasing pivot conveyor, to make it flexible enough to fit within the confined space underneath a vertical form fill seal machine.

Positional accuracy

If accurate product positioning rather than space is the primary concern, as is often the case when product is being fed into a packaging machine, the most efficient conveying solution might well be a timing belt conveyor. Timing belt conveyor systems provide accurate positioning due to the toothed underside of the belt and, according to Habasit Rossi’s Richard Cole, this is an area that has come on in leaps and bounds in recent years.

“Designed for use in packaging conveying and linear movement applications where exact product placement and precise component positioning is required, timing belts can improve efficiency in a broad range of applications, such as packaging, filling lines, component assembly and pick and place systems,” he says.

The company’s HabaSYNC range of timing belts is said to feature precisely formed teeth which, together with the robust steel and aramide cords, ensure consistent and exact positioning.

As a general rule, the further down the line, the more robust conveyors need to be. It follows, therefore, that pallet conveyors need to be the most heavy duty of all. LAC Conveyor Systems claims to offer an extremely durable solution for this demanding sector with its Pallet Roller conveyors.

These feature a powder coated mild steel framework that is said to give the structure great strength whilst allowing for easy maintenance. Removable covers keep the heavy duty loop chain drive free from contamination. Two standard roller pitches are available – 182mm and 103mm – which, combined with the 80mm diameter rollers, provide more than adequate support for loads of up to 2,500kg per pallet, says LAC.

Vanriet is a specialist in secondary handling equipment, and says the secret to the robustness of its conveyors is the stainless steel and bearings it uses. “We manufacture from a 3 and 4mm stainless steel, whereas a lot of companies manufacture from a 1.5 or 2mm steel,” says managing director Paul Farmery. “We also use long-life precision bearings, whereas the industry uses a lot of ‘reclaimed bearings’ which result in reduced reliability and higher noise levels.”

Vanriet has recently supplied Dairy Crest in Nuneaton, UK, with a system for handling, depalletising and transporting 20kg blocks of cheese. The blocks of cheese are delivered on pallets via a pallet conveyor from the maturer to a Rohaco gantry robot for depalletising. The cheese is then transferred via a powered roller conveyor to the process machines, where it is cut, weighed and packaged into individual retail packs. The line has enabled Dairy Crest to achieve its goal of processing 500 tonnes of cheese a week.

Although its specialist area is end-of-line conveying, Vanriet has decided to branch out into primary handling applications, with the launch of a bottling conveyor. Available as either a stainless steel or plastics slat conveyor, the new system is designed for conveying plastics or glass bottles to a secondary packaging machine.

Efficiency factors

Besides choosing the right system for the task in hand, there are other factors that will determine a conveyor’s efficiency. If a system is required that can be used for lots of different pack shapes and sizes, for example, you need to take into account how long it will take to change or adjust the guides.

This is an area Bosch Rexroth has been focusing on, and Mark Dash says it has developed a modular programme which allows the guides to be changed very quickly from one setting to the next. “This gives companies the opportunity to change from one product to another without a couple of hours of downtime,” he says.

FlexLink has also been working on this challenge and says it meets the demands of shorter production batches with solutions for easy resetting of equipment. One such example is the Automated Guiding System (AGS) which allows users to reset the guide rail system for an entire line in a minute.

Customers are also increasingly asking for conveyors that are not just efficient, but also energy efficient, according to Simon Turner, of Cobalt Conveyors. “Although our industry is probably slower than most when it comes to grasping the importance of thinking green, we are being asked by our clients to develop conveying solutions that are environmentally friendly with the definite priority of being energy efficient.”

He says that in practice, this translates to using higher efficiency motor gear boxes, control systems which automatically turn off conveyors when they are not in use, and 24V DC motorised rollers with intelligent plug and play technology.

Processors and packers are looking for value for money from their conveying equipment, be it a pallet conveyor, a spiral elevator or a belt conveyor. And that generally means efficient, flexible lines that run smoothly without any costly breakdowns or glitches.


The conveyor installed by Cobalt Conveyors at Marlow Foods ‘pivots’ on its frame to enable the height of the conveyor outfeed to be adjusted Cobalt LAC Conveyor Systems has launched a new standard range of pallet handling conveyors LAC Astec’s spiral conveyors are said to support high throughput and continuous vertical product flow Astec

Astec Astec
LAC LAC
Cobalt Cobalt


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