If you have just acquired the Fortemo big bag with loading valve and discharge valve, you hold in your hands one of the most demanding and versatile formats in the flexible packaging market. This guide explains, step by step, how to fill it from a hopper, hoist it with a crane or forklift, and dispense its contents onto production lines without losing efficiency or safety. The procedure applies to the complete bag in its single 1500 kg presentation with an inner liner.
This bag connects directly to industrial systems, meaning the success of the process depends as much on operator handling as on the integrity of both valves. Read it completely before the first use: five minutes of reading can prevent a 1500 kg bag from bursting over a plant hopper.
Product Specifications
The big bag with loading valve and discharge valve is offered in a single presentation, optimized for industrial processes with dosing. The following table contains the complete technical specifications of the only available variant:
| Specification | Value |
|---|---|
| SKU | 745235 |
| Material | Woven virgin polypropylene |
| Dimensions | 90 × 90 × 100 cm (3 × 3 × 3.3 ft) |
| Load capacity | 1500 kg (3300 lb) |
| Safety factor | 5:1 |
| Inner liner | Yes (included) |
| Loading spout | Top valve (filling spout) |
| Discharge system | Bottom valve (discharge spout) |
| Lifting loops | 4 reinforced corner loops |
| Base shape | Flat bottom |
| Treatment | UV resistance |
| Packaging | Pack of 30 big bags |
If your operation handles multiple big bag formats simultaneously, the related guides may be of interest: the open-top and flat-bottom big bag guide and the loading-valve and flat-bottom big bag guide cover the contiguous formats in the catalog.
Step-by-step instructions for use
The following procedure covers the complete usage cycle from initial inspection to discharge onto a production line. Follow it in order: each step depends on the previous one, and skipping a step compromises the next.
Visual inspection before each use
Before filling the bag, individually check the four loops, the seams connecting to the base, and especially both valves (loading and discharge). Confirm there are no loose threads, perforations, or open seams. Also check the inner liner: any tear compromises the moisture barrier and allows fines to migrate to the outer fabric.
Positioning on a 1.0 × 1.2 m pallet
Place the big bag on a pallet in perfect condition, with the base centered and all four loops extended upwards. Unfold the top loading valve and temporarily tie it open to receive the flow from the hopper. Ensure the bottom valve is securely tied and folded against the base, never hanging freely.
Controlled filling through the top valve
Connect the loading valve to the packaging tube or hopper mouth. Fill at a controlled flow until the bag reaches its full cubic shape. Do not force additional material once the bag has geometrized: the 5:1 safety factor is calculated for 1500 kg, not for 1500 kg compressed by overfilling.
Before discharging onto a plant hopper, always check that the bottom valve ring is free of hardened dry material. A clump of cement or fertilizer stuck can prevent the valve from closing completely, turning a reusable bag into a single-use one. A quick wipe with a dry cloth between cycles drastically extends the container's lifespan.
Closing the top valve and hoisting
Once filled, fold the loading valve inwards and tie it with a double knot (not a single knot, which can loosen). Pass the crane hooks or forklift tines through all four loops simultaneously, never just two or three. Lift slowly and verify that the bag rises level, without tilting to either side.
Dosed discharge through the bottom valve
Position the bag over the destination hopper, mixer, or silo. Untie the bottom valve loop with one hand while the other holds the spout to control the flow. To stop discharge, re-tie the valve. Once empty, inspect the bag before storing it for reuse in the next packaging cycle.
Never hoist the big bag with fewer than all four loops attached, even if it seems two are enough. The 1500 kg payload is calculated based on symmetrical tension at all four points. Hoisting with two loops concentrates force on specific seams and will tear the bag during the first long transport. This is the most expensive and most common mistake on construction sites and in plants.
Compatible with your hopper or packaging system?
If you have doubts about whether this double-valve big bag fits the mouth of your filling system or the funnel of your mixer, consult the virtual assistant. It will guide you on typical valve diameters, fastening systems, and plant configurations so you don't buy a bag that you then cannot connect.
Complementary Products
To get the most out of your double-valve big bag, consider the following complementary products. Each one covers a specific need in the logistical flow, from diversifying your bag inventory at the plant to protection during transport:
The big bag with a top filling spout is the version without a bottom discharge, useful when the material is emptied by cutting the bag at the end of the line. The open top big bag handles bulky loads that do not fit through a valve. The transparent manual stretch film protects the palletized bag during transit, especially useful when the operation crosses docks or is moved outdoors. The plastic corner protectors reinforce the four corners of the pallet when the bag is secured with strapping for export operations.
Maintenance and care
If you plan to reuse the bag for multiple cycles—which is where this double-valve format truly pays off—maintenance between uses is crucial. Store empty big bags folded indoors, on a clean and dry surface, away from direct sunlight. UV radiation degrades polypropylene over time, even in bags with factory UV treatment like this one.
After each cycle, dust out the inner liner by shaking it upside down and pay special attention to both valves: any residue of cement, fertilizer, or hardened resin in the sleeve will render them unusable for the next filling. Do not wash the bag with water unless expressly indicated by the manufacturer of the material being packaged, as woven polypropylene absorbs moisture in seams and weakens the weave if not completely dried.
Frequently Asked Questions (FAQ)
Can I reuse this big bag after a loading and unloading cycle?
Yes, the double-valve format is designed for multiple packaging cycles. The key is to inspect the seams, both valves, and the inner liner before each reuse. If any damage is detected in a valve, the bag becomes single-use: the valve is the critical area that defines the container's lifespan.
Is it suitable for fine and abrasive materials like cement, plaster, or pigments?
Yes, this is precisely one of its main applications. The inner liner isolates the material from the outer fabric and blocks the migration of fine particles. The top filling spout allows direct connection to the plant's packaging mouth, preventing dust dispersion during filling, and the discharge valve dispenses the clean material into the mixer or destination hopper.
Are the valves compatible with standard packaging systems?
The Fortemo big bag's filling and discharge valves follow common industrial dimensions, allowing them to connect with most packaging mouths and hopper funnels on the market. If your installation has a non-standard coupling or a patented system, it's advisable to confirm the sleeve diameter before the first cycle. The virtual assistant can help you with this verification if you share your equipment reference with us.