Spout bottom bulk bags

Anatomy of the outlet

A discharge spout is a fabric tube sewn into a hole in the base panel. It hangs below the bag when open and is folded up against the base when closed. The inner tie cord pinches the tube shut. On most builds a second layer covers it: four petal flaps, or a star of fabric points, that fold over the tied spout and lace together so the tie is not the only thing holding the load.

Spout size is the field that matters most. A wider tube empties faster and resists bridging; a longer one reaches down into a hopper throat or a sealed unloader collar. A full discharge bottom takes this to the limit, with a spout nearly as wide as the base for product that will not pass a narrow outlet. Optional extras include a reinforcing patch around the junction with the base, a longer tie finished with a toggle, and a protective cover flap stitched along one edge so the folded spout stays tidy during transit.

Discharging spout bottom bulk bags

Lift the bag by all four loops onto a discharge frame or hold it over the receiver with a forklift and a lifting bar. Open the petal flaps first, pull the spout down into the hopper inlet and only then release the tie. The product column drops and starts to run.

Flow can be slowed by taking a few turns of the tie around the spout, and on some jobs it is stopped altogether so the bag can be moved half empty. Massaging or vibrating the bag helps powders that arch over the outlet. Never reach under a hanging bag to clear a blockage; lower it first, or poke from the side with a nonmetal rod.

Filling is the reverse problem. Before the product goes in, make sure the spout is tied and the flaps are closed, or the first bucket ends up on the floor.

Plants with dust rules often go further than an open hopper. The spout can be clamped into a sealed collar, drawn under an extraction hood, or fed straight to a rotary valve or screw conveyor that pulls product at a steady rate. Each of those sets a definite spout length and diameter, so the receiving gear dictates the bag, never the reverse.

Folded for the trip

For shipping, the bottom spout is pushed up inside the bag, the body is folded flat and the bags are banded into bales. A spout bag takes a little more room in a bale than a flat-bottom bag of the same size because of the extra fabric, which can change how many bales sit on a pallet. That number comes off the packing specification for the exact bag.

The freight is planned from there: pallets per order, LTL for a few pallets, a full trailer when the volume and your storage space allow. Keep the bales wrapped until use so dust and moisture stay off the spouts.

Spout, flat or full-open bottom

A flat bottom is the plain choice when the bag will be slit over a pit or bin. It is cheaper to make, but cutting the base ends the bag, so it can never be a multi-trip bag. A spout lets you meter, stop and restart, and leaves the bag whole for inspection afterward. A full-open bottom suits coarse or cohesive material that stalls in a standard tube.

Troubles at the outlet and their usual causes

Most discharge complaints trace back to a mismatch between the powder and the tube. A few patterns repeat across plastics compounders, feed mills, glass plants and concrete batch yards.

• Rat-holing: a narrow channel empties down the centre while the rest stays put; a wider spout or gentle paddling helps
• Arching: fine material forms a bridge over the opening; vibration or a massager frame breaks it
• Leaking at the tie: the cord was knotted loosely or the flaps were skipped
• Spout too short: product sprays around the hopper rim and dusts the room
• Spout too long: fabric folds inside the inlet and kinks shut
• Spout dragged on the floor: abrasion weakens the stitching where it meets the base

Writing the request

Measure the inlet the spout must enter before you ask. A tape across the throat of the hopper, plus the drop from frame to inlet, tells us both numbers. Then send the spout size and closure, the top, the SWL, the static type and any liner. Include quantity and the ZIP of the dock that receives them. We will match the bag to that and plan the load.