Duffle top bulk bags

How duffle top bulk bags are built

Start at the top panel. On a duffle bag the whole top is left open and a tube of fabric, the skirt, is sewn around that opening. Before filling, the skirt hangs over the sides or is folded down inside. During filling it stands up around the chute. Afterward it is bunched, twisted and tied with a cord that is stitched to the skirt so it cannot go missing on the floor.

Below the top, the body is ordinary FIBC construction. A four-panel bag is sewn from four side pieces and a base. A U-panel bag uses one long piece folded under the base with two side panels added. A circular woven body comes off the loom as a tube, so it has no vertical seams. Any of the three can carry a duffle.

• Skirt: the fill opening and closure in one piece of fabric
• Tie cord: sewn to the skirt, used to gather and knot it shut
• Loops: four, stitched at the corners or along the side seams
• Document pouch: holds the packing slip or product sheet
• Bottom: flat panel, or a spout for controlled emptying

Under the chute, then over the hopper

Hang the bag in a fill frame by its four loops so the body opens square. Pull the skirt up around the chute, or open it wide for a bucket, and start the product. Rock or vibrate lumpy loads partway through so they settle and the bag stands upright; a lopsided bag tips when forks pick it up. Stop at the weight on the label, not at the top of the skirt.

To close, gather the skirt above the product, twist it into a neck and tie it off. For dusty material, fold the twisted neck back on itself and tie again, the gooseneck method, which keeps fines from working out on the road. Tuck the tied skirt down so a forklift operator cannot snag it.

Emptying depends on the bottom. A flat bottom is lifted over the receiving bin and cut open, which ends that bag's life. A spout bottom is untied over the hopper and the flow is controlled with the spout tie. Keep people clear of the area under a suspended bag every time.

Bales, pallets and the truck

Empty duffle tops travel folded flat with the skirt laid inside the body. A stack of them is compressed and strapped into a bale, and bales are stacked on a pallet and stretch-wrapped. How many bags a bale holds depends on fabric weight, height and whether there is a spout, so we work from the maker's packing list instead of guessing. Receivers without a forklift or pallet jack can ask for a liftgate truck, though that narrows which carriers will take the shipment.

A pallet or two of bales rides LTL. A larger order may fill a trailer, which usually lowers the freight per bag but needs a dry place to keep the extra pallets. Store bales indoors and out of sunlight; UV softens polypropylene and powders the surface of the fabric, and a sun-faded bag should not be lifted.

Duffle, spout or open: picking the top

The top is chosen by how product arrives at the bag. Wide, irregular streams want a big opening. Fine, dusty, metered streams want a sealed connection.

Where these bags turn up, and what goes wrong

Sawmills bag shavings and sawdust in them. Landscape suppliers and nurseries sell bagged stone, bark and soil by the yard. Roofers drop shingle tear-off into them from the eaves, demolition crews fill them with broken brick and drywall, foundries return spent sand, and composting sites load screened product off a belt. In each case the stream is irregular, and a narrow inlet would choke.

Most trouble starts at the top. Watch for these habits on a busy floor:

• Heaping product into the skirt until it can no longer be gathered or knotted
• Closing with wire or baling twine, which can saw through woven polypropylene
• Leaving the skirt flapping on a flatbed, where highway wind shreds it
• Dragging a loaded bag by one loop instead of lifting by all four
• Stacking bags whose domed, tied tops leave the upper tier wobbling

What a duffle top quote needs from you

Send the SWL, the footprint and height, the bottom you empty through and the static type. Add how many bags, how often, and the ZIP of the fill line. If you are matching a bag you already use, a photo of its label answers most of this in one shot. From there we work out bales per pallet and whether the order rides LTL or on its own truck.

Mention anything unusual about the jobsite as well. Bags that will sit outdoors through weeks of weather, bags lifted by an excavator bucket hook or a crane, and loops that must slip over long forklift tines all change what we look for in fabric weight, UV treatment and loop length.