Air conveying

How does it work?

All air conveyors share several basic operating principles that are as follows:

Use of air as the transport medium.
Containers are moved using a high volume of lowpressure air to transport the product along the conveyor path.

The major differences among the leading air conveyor manufacturers are the following:

Where the air is directed against the product, container, or bottle
How the airflow is created (design of motors and fans for maximum efficiency)
Where the airflow is created: one large blower vs multiple small blowers
Construction details and ‘‘user-friendly’’ features of the air conveyor

See Figures 1–3 for air conveying operations.

Airflow inside plenum. Figure 1.

Plenum, cutaway view. Figure 2.

Single-lane air conveyor, adjustable bottle guide. Figure 3.

How does the air conveyor solve the problems found with the chain conveyor, and why is it the better method of conveying?

It eliminates crushing. The air conveyor moves the packages by a directed flow of air against the containers. The flow of air can be controlled throughout the air conveying system. In this way, crushing of packages is eliminated as follows:

By reducing the backpressure force against the first product in a long line of products in a backfeed condition.
By controlling the velocity of the product through the use of manual or automatic baffles, one can reduce the impact force of a product arriving from upstream and reduce damage.
By introducing lift holes in combination with louvers, the product can hover while using the conveyor for accumulation on the flat-top air conveyor—no marking of crushing is evident from the friction caused by the belt or chain.

In beverage applications, the bottles cannot fall, which is detailed as follows:

The bottles cannot fall when the bottle is transported hanging by the neck support ring.
Eliminating bottles falling down on the conveyor and getting caught in the starwheels or timing screws.

As a result, users of air conveyors derive the following benefits:

Gapless filling. At the higher production speeds, even small inefficiencies are costly and unacceptable. Air conveyors will virtually eliminate the possibility of a missed cap or container by assuring that a sufficient supply is provided to the infeed of the filler, rinser, capper, or packaging equipment. In the event of a ‘‘hiccup’’ of the upstream equipment, bottles, caps, or other products from upstream will be conveyed quickly, which allows the line to recover.
Shorter surge areas. Faster conveying speeds allows for quicker recovery from the upstream supply of a product to the rinsers, fillers, cappers, or packaging equipment. As a result, users of air conveyors will be able to greatly reduce the lengths of a conveyor to accommodate surges.
Reduction in buffer areas (BIDI tables). For the same reasons as described above, bidirectional accumulating tables can be eliminated. There still may be the need for accumulation as, for example, where the labelers need to be changed over. For beverage applications we recommend side lengths of air conveyor where the bottles can be diverted for additional accumulations as the most effective means of accumulating and preventing bottles from falling over.

The net result of these advantages is less overall length of conveyor in the plant. This length reduction also results in both lower cost for the conveyor installation and freeing up of valuable plant space at floor level.

Characteristics of a properly designed air conveyor

Construction Materials

We recommend and use stainless steel construction for the conveyor; this material will result in lowered maintenance costs and in easier washdown. Most importantly, the use of stainless steel guiderails on neckring a air conveyor avoids the need to replace guiderail wear strips.

Airflow

In cap conveying applications on flat-top air conveyors, center louvers are the most efficient. On heavier parts, the addition of lift holes combined with louvers aids the product flow, especially where accumulation is required. The three methods used most commonly are neck blow, shoulder blow, and sidewall blow in neckring air conveyor applications. In these applications, we feel that neck blow is the preferred method, because most bottles have the same neck dimensions as compared with body diameter dimensions. Using the neck dimension as the criterion, adjustment for different sized containers is reduced.

Flat-Top Air Conveyor Applications

The food industry found a solution in a flat-top air conveyor and, in turn, is a major user of it. Because of the flat-top air conveyor’s ability to convey with virtually no damage to the product, the manufacturers of candy, for instance, turned away from conventional tabletop conveyors and turned toward air conveyors. Because of the flat-top air conveyor’s ability to lift as well as convey, the air conveyor can be used to accumulate products, eliminating the damage caused by friction from a belt or chain. These features make the air conveyor the product transportation vehicle of choice.
The beverage industry has changed significantly with the growth of the 16- and 20-oz bottles. Use of 28- and 38- mm plastic beverage caps has grown as well. The beverage industry was now looking for a versatile method of conveying them while maintaining orientation to the capper. Their solution was to use an air conveyor coupled with a cap feeder/orientor. In general, the bottlers were now able to convey their caps quickly, efficiently, and 100% oriented to their cappers at speeds to 1800Hz from remote locations, such as warehouses and production facilities.

Beverage industry applications

Faster Filling Speeds

Filling line speeds have and will continue to increase. Our company is now involved with projects where the required line speeds are as follows:

2-L container: 800/min
20-oz bottle: 1100/min
16-oz bottle: 1200/min

Our company’s Airtrans Air Conveyor installations have been to provide better control of the containers out of the depalletizers that are running at higher speeds.

One-Piece and Single-Serving Bottles

Because of their higher center of gravity and thin-walled, lighter design, most one-piece bottles are inherently less stable than the base-cupped bottle. Also, in recent years, an increase has occurred in market share for the 16-oz and now the newly introduced 20-oz PET bottles. These containers are less stable on filling lines than the 2-L bottle, and they fall over more easily than the glass bottles they replaced. The higher filling line speeds of the smaller bottles (up to 800 bottles per minute) continually aggravate the problem of the bottles falling over and jamming on the conveyors. The neckring air conveyor virtually eliminates these problems by conveying quickly, cleanly, and with little to no jamming or tipping. Because the bottles are suspended by the neckring, the possibility of tipping is eliminated. Also, because the bottles are conveyed with air, there is much less back pressure exerted on the new, thin-walled bottles, significantly reducing damage. (see also Carbonated beverage packaging)

Marketability

A major trend has been the expansion of blow-molding plant outputs, in terms of both total output and numbers of packaging lines. This growth 6L in output has resulted in an increased need to eliminate cable or chain conveyors and in an increased implementation of air conveyors. Bottlers are splitting the output of their blow molding machined into several streams to downstream packaging equipment and combining the output of multiple blow molders into their packaging equipment. However, as shown in the applications of flat-top air conveyors, the applications of air conveying are not limited to blow molding applications by any means.

Problems of Conventional Tabletop Conveyors Needing Solution

The following problems of cable and chain conveyors are commonly known by the industry:

Greater nonproductive costs of mechanical conveyors because of higher maintenance of high-speed chain conveyors—mechanical conveyors have moving parts that are subject to wear and mechanical failure.
The following spare parts are required:
1. Chain
2. Wear strips
3. Gears
4. Sprockets
5. Bearings
Expense for disposable lubricants and wear parts
Unsanitary—grease and constant soap on bottles and product
Higher unplanned downtime of tabletop conveyors—these mechanical components will fail unexpectedly
Greater crushing of lightweight plastic bottles and delicate packages
Bottles fall over
Bottles jam on tabletop conveyors

Benefits of air conveyors and elimination of popular myths

Expense

An air conveyor system can actually be more cost-effective than chain, belt, or cable conveyor for the same application. Although initial costs of an air conveying system may be more, the reduced maintenance, amount of spare parts, and downtime make air conveying an overall less expensive method of transport. Basic capital expenditures of the conveyor are only part of the complete cost picture. The true and total cost of the conveying system also includes the following:

Spare parts. The air conveyor needs and uses less. Few moving parts exist on an air conveyor so the initial capital for spare parts and yearly additional parts’ costs are less than for mechanical conveyors.
Maintenance labor costs are less than for mechanical conveyors. Because few moving parts are present, it is less likely to break down and need repair breakdown and need of repair.
Air conveyors can be more readily located overhead. These savings in floorspace costs may be applied as cost saving.

Flexibility

Air conveyors offer significantly more flexibility than chain conveyors for the following:

Revisions to floorplan. Both flat-top and neckring air conveyor systems are furnished in sections that bolt to each other in a continuous path. The modules typically are combinations of straight sections, horizontal curves, vertical curves, and gates for merging and diverging. Any of these modules can be reconfigured in a different combination and can be added or deleted. Our company reconfigured a system that had been shipped four years previously, and by adding additional sections to the original system as well as by adding other new sections, we provided a totally different conveyor system layout. Few of the old sections were wasted; rather they were reused elsewhere in the new conveyor line. The entire system was reconfigured with less than one week of installation and dismantling.
Multiple sizes of containers. The flat-top air conveyor can generally carry 5 lb/ft2. Also, our flat-top air conveyor can be designed to accommodate many differently sized products. Whether it be through a dual-lane, multi-lane, or single-lane flat-top air conveyor, from unwrapped candy to boxes to caps, a virtually endless variety of products can be transported using this system.
Multiple sizes of beverage containers. Multiple sizes of containers are accommodated using several different techniques. Different heights of containers are accommodated by adjusting the height of the air conveyor through hand wheel adjustment or automatically. The air conveyor transports bottles hanging by the neck support ring. The Aidlin Airtrans has hinged end sections on the infeed and discharge ends of the air conveyor. Similarly, the height would be adjusted when discharging bottles to the infeed screw of the filler. Infeed and exit plenums are hinged to allow adjustment of bottle height in the air conveyor. Also, bottle heights from the same supplier can have height variations for which the conveyor may need to be adjusted. Fixed height neck rails obviously do not have the necessary adjustability for this condition. Different neck diameters are accommodated by Aidlin’s Dual-Lane Airtrans. The Dual-Lane Neck Ring Air Conveyors is a double-lane neck rail. One lane is set up for 16-oz bottles, whereas the other is set for 2-L containers; similarly, one lane could be set for 28-mm neck finishes and the other lane set up for 38-mm neck finishes (as on 3-L containers). A single air plenum is switched over to supply either set of neck rails as required.

Interfacing with Other Equipment

One significant advantage of both flat-top and neckring air conveyors is their ability to interface easily with other packaging equipment (see also, Blow holding; Labels and labeling machinery; Palletizing).

Mechanical interfacing

The flat-top air conveyor can transport from and to most equipment: from the orienting orientors to the cappers, liners, or decorators; or to a wrapper, cartoner, or case packer. When needed, the air conveyor can be fit to virtually any line. The transport process is described as follows:
Blow molders. Bottles are received either through a bottle collector conveyor (as on the Cincinnati, Magplas, and Nissei) or directly from the output neck rails (as on the Sidel and Krupp).
Palletizers. An escapement is mounted to the discharge of the air conveyor to stabilize the bottle and match the container’s speed to be the same as the infeed conveyor to the palletizer.
Depalletizers. Containers are received off the outfeed conveyor directly to the split neck rails of the air conveyor. The bottles are accelerated and conveyed away from the palletizer at a faster line rate than the depalletization. In this way, no possibility exists of bottles falling down.
Labelers. Containers can be placed directly into the infeed starwheel or timing screw of the labeler.
Fillers. Bottles are placed directly into the infeed timing screw of the filler. By assuring a proper backpressure and constant supply of bottles, maximum filling speed is achieved.

Maintenance

The total maintenance factor of the air conveyor is significantly less than that for mechanical conveyors. For example, the normal maintenance in the Airtrans system consists of replacing, in less than one minute, the 5-mm fan filters as needed. In our flat-top air conveyor, both the top guiderail and the Lexan covers are hinged for easy cleaning.

Less Contamination to Products

Based on R&D done at Aidlin Automation in Bradenton, FL, the air transporting the bottles or products is filtered, in our case, to 5 mm. The net result is that bottles or products, such as food or caps, remain cleaner than in the typical plant where the neck, cap, or product is open to unfiltered ambient air.

Conclusion

As one clearly can see, air conveying provides the alternative to chain, cable, or belt conveyors. Air conveying provides clean, consistent, and predictable performance. The new generation of conveying technology is here and in great demand. To be profitable in this quickly changing industry, one must keep up to date with new technology—and that is the air conveyor.