Big bag filling options: inlet types for every filling line
The top of a FIBC can be fully open, closed with a flap or skirt, or fitted with a spout for automatic filling. Here is how the inlet types compare.
Open top, flap, skirt, inlet spout, spout with flap and conical top: the big bag inlet decides how fast you fill and how well the product is protected.
A big bag (FIBC) can be filled through an open top, a flap, a skirt, an inlet spout or a combination of spout and flap. The right inlet depends on two things: how you fill the bag (by hand, with a loader or on an automatic filling machine) and how much protection the product needs against dust, rain and contamination. Inlet spouts and skirts are the standard choices; open tops are the cheapest.
DIV Trades produces every inlet type listed below in-house. Spouts and skirts are made from light coated or uncoated fabric, flaps from heavy fabric, see the fabric specification. Combine the inlet with any discharging option and any loop type.
FIBC inlet types compared
Open top
The simplest and cheapest FIBC. The top cannot be closed, so the product is not protected. Open-top bags are used for stone, sand, building materials and other goods that withstand rain, humidity and sunshine. They can be filled manually or automatically; the fabric edge is folded over to avoid sharp edges.
- Easy filling by hand, loader or machine
- The cheapest inlet
- Goods are not protected from weather or dirt
Flap (flat inlet)
A lid made from heavy fabric, sewn to one side of the top and closed with ties on the other side. It protects the product from sunlight but does not seal the bag.
- Protection against the sun
- Simple to open and close
- Poor closure, dirt can fall in
Inlet skirt
A standard FIBC inlet. The skirt is a fabric collar sewn to the full top of the bag and closed with ties. It protects the product from external influences and contamination and is the usual choice when there is no automatic filling machine. The skirt height is proportional to the bag dimensions and it is made from light coated or uncoated fabric.
- Excellent product protection
- Does not require an automatic filling machine
- Full-width opening for fast filling
- More expensive than an inlet spout
Inlet spout
A standard FIBC inlet. A top cover with a central opening carries a spout with closing ties. Designed for companies with filling machines: the spout is pulled over the filling head so no dust escapes. Diameters of 30 to 50 cm and a length of 50 cm are most common; other sizes are made to order. The spout is made from light coated or uncoated fabric.
- The best protection for the product
- Cheaper than a skirt inlet
- Dust-free filling in your plant
- Requires a filling machine
Inlet spout with flap
An inlet spout plus a heavy-fabric flap that covers the tied spout. The spout protects the product and the flap protects the spout. Both have their own ties.
- Double protection for the product and the spout
- One extra opening and closing operation at filling and discharging
Inlet spout with conical top
Like an inlet spout, but the top cover is cut conical so the product fills the top corners of the bag completely. Chosen when maximum use of the bag volume matters.
- Better use of the volume in the top corners of the bag
- More cutting and sewing than a flat top cover
Optional umbrella cover against rain
Big bags with a skirt or inlet spout can be fitted with an umbrella. It covers the top seams so no water can enter the bag at these points, which is useful when filled bags are stored outdoors.
Inlets for special bag types
UN big bags
On UN big bags the top must be closed with a spout or a skirt so that the hazardous material stays inside the bag if it tips over.
Big bags with inliner
The inliner of a big bag with inliner can be sewn to the inlet spout or skirt, or inserted loosely into the bag. Sewn-in liners stay in place during automatic filling.
Ventilated big bags
Ventilated big bags can have a skirt made from ventilated fabric so that air flows through the top of the bag as well as the body.
One- and two-loop bags
One- and two-loop bags have slightly different inlet options. Open inlet, skirt and inlet spout are all possible, but open inlet and inlet spout are used in most cases.
Match the spout to your filling head
Send us the diameter of your filling head and the free height under it. We size the inlet spout diameter and length so the spout fits over the head without tension and ties off cleanly.
Which big bag inlet is best for automatic filling?
An inlet spout. It is pulled over the filling head, keeps dust inside and gives the best product protection at a lower price than a skirt.
Which inlet should I choose without a filling machine?
An inlet skirt. It opens the full top of the bag for filling by loader or hand and still closes tightly with ties.
What size is a standard inlet spout?
The most common inlet spouts are 30 to 50 cm in diameter and 50 cm long. Any other diameter and length can be made to order.
Can an open-top bag be protected from rain?
Not an open top itself. Choose a flap for sun protection, or a skirt or spout with an optional umbrella cover for rain protection.
Is the inlet spout coated?
Spouts and skirts are made from light coated or uncoated fabric according to your requirement; coated fabric is the usual choice for powders and moisture-sensitive goods.
Not sure which inlet fits your line?
Our sales team will recommend the inlet type, spout size and fabric for your product and filling equipment.
Request a quote