Spout top bulk bags
A spout top bulk bag has a fabric tube sewn into the center of its top panel, so product goes in through a narrow neck that fits over the filling head and is then tied shut. It is the usual pick for powders, pellets and granules filled from a spout or chute, and it pairs with either a flat bottom or a discharge spout.
| Top | Filling spout, often 14 in diameter x 18 in long, with a tie |
|---|---|
| Bottom | Flat, or a discharge spout for controlled emptying |
| Footprint | 35 x 35 in is common; 41 x 41 in for light product |
| Body build | Four-panel, U-panel or circular woven |
| Fabric | Woven polypropylene, coated or uncoated |
| Loops | Four corner or cross-corner loops |
| SWL | Commonly 2,000 to 2,200 lb |
| Safety factor | 5:1 single trip; 6:1 only on a bag built and labeled for multi trip |
| Static type | Type A unless the product or the area calls for B, C or D |
| Extras | Document pouch, spout tie, optional liner with its own neck |
Good for
- Fine powders that would cloud out of a wide opening
- Plastic pellets and regrind dropped from a hopper
- Sugar, salt and flour on food lines, in new bags only
- Fertilizer and seed filled under a spout
- Mineral powders such as talc, lime or silica flour
- Stations with an inflatable or clamp-collar filling head
Not for
- Chunky or irregular pieces that won't pass the neck
- Loading with a shovel, skid steer or loader bucket
- Firewood, produce or bulky scrap
- A fill station with no spout, chute or head to clamp to
Put this in the request
- What is the outside diameter of your filling head, and how much tube do operators need to clamp and tie?
- Flat bottom or discharge spout, and what outlet size does your unloader take?
- What is the product, and roughly what does a cubic foot of it weigh?
- What weight do you fill each bag to?
- Single trip, or a multi-trip bag on a closed loop you control?
- Does the product or the room need a Type B, C or D bag?
- Do you need a liner, and should it have its own fill neck?
- What ZIP is the fill line, and can you receive a full trailer or only LTL pallets?
Part by part: neck, panels and loops
The part that names this bag is the filling spout: a short tube of woven fabric stitched into a round hole in the top panel. It slides over the fill head, product drops through it, and then the tube is gathered, twisted and tied. Plenty of buyers ask for a 14 in by 18 in spout because many filling heads are built around that size, but the correct size is whatever fits your own head with a little slack for the clamp.
Under the top panel, the body can be four-panel, U-panel or circular woven; the spout doesn't care which. Loops are sewn at the four corners. A document pouch on one side holds the packing list or lot ticket, and the label stitched nearby carries the SWL, the safety factor, the static type and the maker's details.
At the bottom you choose between two things. A flat bottom is plain and costs less to make; the bag is emptied by cutting it. A discharge spout lets you open, throttle and close the flow over a hopper.
What happens at the filler and the unloader
At the filler, the operator pulls the spout over the head and clamps it, or an inflatable collar grips it, so dust stays inside. The loops hang on the frame's hooks. Many lines puff a little air in first to square the bag before product flows, and some vibrate it during the fill to settle the contents. At target weight the neck is gathered, tied and tucked down so it won't snag on the next bag or a forklift mast.
At the far end, a bag with a discharge spout is hoisted over the unloader, the spout is untied inside the hopper's access box, and product runs out without fogging the room. The same bag with a flat bottom has to be slit over a grate. That works for coarse pellets and is a mess with flour.
Fill to the weight printed on the label, not to the top of the neck. A full spout is not extra rated capacity.
When dust does escape, the cause is nearly always the seal at the head: a neck that's too wide pleats under the clamp, a torn hem, or someone started the feed before the collar inflated. Check the stitching for fraying before clamping, swap a damaged bag rather than taping it, and keep spare ties at the station so nobody improvises with wire.
How a load of them leaves the maker
Empty spout top bags fold flat with the neck tucked inside, then get pressed into bales and strapped. Bales stack on pallets, the pallets are stretch-wrapped, and the pallet is the unit we plan around. How many bags fit in one bale depends on size and fabric weight, so we confirm the count with each order instead of quoting a standard number.
One or two pallets ride LTL. If your line burns through bags steadily, a full trailer usually costs less per bag and arrives in one drop, provided you have covered, dry floor to keep the bales out of the sun. Sunlight softens polypropylene, so bales stored outdoors start losing strength before a single bag is filled.
Against duffle tops and open tops
A duffle top is the nearest relative: the whole top is a skirt that gathers and ties. It takes lumpy product and wide chutes, but it leaves more loose fabric to wrangle and lets more dust out during the fill. If your station has a real fill head, the spout top is the tidier choice.
| Top | Where it fits |
|---|---|
| Spout top | Fill head or chute; dusty or free-flowing product; closed top wanted |
| Duffle top | Wide chute, hand loading or lumpy product; closes with a tie |
| Open top | Bucket or conveyor loading; no closure unless you add a cover |
The details a spout top quote needs
Measure the head before you write. Give us its diameter, the length of tube your crew needs, the product, the fill weight, and whether you want a discharge spout underneath and what size. Then the ZIP of the fill line and how many bags a month you run. From that we lay out the load: bales, pallets, LTL or truckload, and a delivery day we confirm with the carrier before we tell you.
Questions
Can a spout top bag be emptied through the top?
No. The top spout is only for filling. A flat-bottom bag is emptied by cutting it open over a hopper or grate; a bag with a discharge spout empties through that.
Does the spout size matter if my filler has an inflatable collar?
Yes. The collar can only seal inside a tube that fits it. Too narrow and it won't go over the head; too wide and dust leaks past the seal.
Can I get used spout top bags?
Sometimes, for sand, gravel or aggregate, after inspection. We don't promise any used bag is fit to fill again, a 5:1 bag is rated for one trip, and food or static-sensitive products always go in new bags.
Can the liner have its own fill neck?
Yes. A lined spout top bag usually has a liner neck running up through the fabric spout, so the head clamps onto the film and product never touches the woven tube. Give us the head size so both necks fit.
Request spout top bulk bags
The spec from the label, the count and the ship-to ZIP. We confirm the spec, build the load and come back with the freight and the delivery window.