Packaging and Stylish Bags

Prevent to 100% Product Yield Using Bulk Bag Liner

In a preferred form of the invention, a liner for a bulk bag of the type used in storing and transporting materials has a flexible plastic bottom and sides that define a storage space.  The liner may be reused by removing the stitching and removing the liner from the bulk bag for cleaning. The liner has a reinforced plastic collar that extends from the sides distally from the bottom and means for releasable fastening the reinforced collar to the sides of a bulk bag as with stitching.

Often bulk bags require inner liners, usually made of polyethylene, to protect the ingredient.  Care must be taken when discharging lined bulk bags to prevent entanglement with downstream equipment and to ensure 100% product yield.

During storage and transportation of a filled bulk bag and liner, any tearing T of the liner caused by its movement relative to the bulk bag, which often occurs due to the weight of the fungible materials therein, is likely to occur in the top collar where it is joined to the bulk bag by stitching. However, this tearing of the liner is limited due to the reinforcement of the collar material. Moreover, this tearing of the collar does not cause a breech of the liner portions containing the material, thus preventing contamination of the bulk bag.

bulk bag with liner

By “reinforced” is meant herein that the flexible material is more tear and rip resistant than the material of the principle sides of the liner. Examples of such are reinforced materials are woven materials and non woven fabrics, either solely or as an additional ply or laminate to the principal liner side material which is typically blown plastic film. It should be appreciated that once blown films are perforated, as with sketches, they are susceptible to being ripped or torn in the area of perforation.

Liner tensioners vary in their operation, but the most basic simply hold the liner in place preventing it from moving out of the bag.  More sophisticated tensioners wind up a portion or all of the liner as it is emptied.

Before the bulk bag is lifted into the discharger the inlet spout of the bag is untied to expose the tied liner inlet.  The liner neck is then wound onto the liner tensioner spool piece, which is then either fixed in place or rotated to take up the slack in the liner by activating its actuator (typically pneumatic).

Liner Tensioner Considerations

1. Liners ‘grow’. Loose liners and liners attached to the top of the outer bulk bag will extend out of the bulk bag outlet spout during ingredient discharge.
2. Too much liner winding. If a liner tensioner that winds continuously is used typically the liner outlet is clamped to prevent it from winding all the way up onto the spool piece. 
3. Liner length. When a liner tensioner is used the liner inlet must be long enough to reach the tensioner spool piece.
4. Ensuring yield.  A liner tensioner that winds up a loose liner – partially or completely – can assist with ensuring that all of the ingredient is discharged from the liner. 

An improved liner for bulk bags is now provided which protects bulk bags from contamination to allow for their reuse. While this invention has been described in detail with particular references to preferred embodiments thereof, it should be understood that many modifications, additions and deletions may be made thereto without departure from the spirit and scope.

Flexible bulk containers provide promising new markets

The commodity crunch

Nicknamed bulk bags, these large fabric containers usually have forklift straps at the top and discharge chutes at the bottom, with the vast majority identical cube-shaped containers made of welded polypropylene. The basic bags have plummeted to a quarter of their 1980s price, and margins are slim.

But many bulk bag makers have turned their attention toward new markets and are manufacturing specialty or custom bags at their customers’ behest. There may be less shipping overall, but these companies are trying to make sure that more shipping is done in fabric containers. Simons agrees. Silos defeat the purpose of FIBCs, she points out. When bulk bags are empty, they can be stacked flat, taking up almost no space in the warehouse.

Indeed, FIBC makers are doing all they can to supplant metal containers. AmeriGlobe has introduced freestanding drum bags that can be lifted by the straps like FIBCs, but can be filled using drum-filling equipment. It has introduced a pallet-free bag that can be forklifted from the bottom via a set of rigid polypropylene channels. The all-in-one design saves labor and space, since the bags can be stacked without loading them onto pallets.

fibc bag

Risk reduction

To make warehouses safer, FIBC makers have created special bags that are designed to dissipate static electricity. “A material such as titanium dioxide has got to have a bag that will discharge the static,” Griffith says. Many compounds are caustic, corrosive or reactive, and have to be kept in specially lined bags. Some bulk bags are lined for a different reason: to provide the cleanest environment possible for the goods inside. That’s the case with B.A.G.’s Pharma Bags, which are small (3-40 cubic feet), lined and baffled bags intended for pharmaceutical ingredients.

During one on-site visit, AmeriGlobe staffers found that seed companies filled some of their bags only part way. They wanted to buy and sell seeds by seed count, not volume, but because the seed sizes were inconsistent, the product didn’t always fit the bags. Unfortunately, incompletely filled bulk bags have a tendency to slump, causing dangerous stacking and transport problems.

We can handle the whole range of possible seed counts in two bag sizes instead of four, so our customers don’t have to invest as much in bag inventory.”

Better bags, bigger markets

The margins for commodity-type FIBCs are continuing to shrink. The key to creating growth under these circumstances, Simons has found, is to introduce the bulk bags into new markets that have not previously used them. Slowly, over the past five years, they are becoming accepted in the U.S. The advantage is that they can bring gravel or any type of building material to the site and stage it before it’s needed, as opposed to bringing it in with a dump truck, and a lot of times, they’ll reuse the bags.

By: Jamie Swedberg

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