Effective raw material storage is a foundational step in plastics processing. It preserves material properties, reduces contamination risk and supports defect-free production. The supply chain for polymers involves diverse packaging formats depending on origin and material type, from aluminium-lined or 20–25 kg polythene bags used for technopolymers, through big bags and octabins, to bulk deliveries by 25‑tonne road tankers and rail. Across these formats, storage should interface seamlessly with automatic conveying to limit manual machine feeding. Because production setups, quality requirements and sector constraints vary, storage solutions must adapt to different plant layouts and operating practices while maintaining process control and traceability.
In basic bag handling, material is transferred from bags into bins that allow side suction to the hopper of an injection moulding machine, ensuring continuous operation. To match throughput targets by hour, shift or day, bins are available in multiple sizes and can be equipped to enhance safety and reliability. For challenging materials such as poorly flowing regrind or flakes, dedicated containers and discharge aids improve handling consistency. The following overview summarises Moretto’s solutions as described by the company, including indoor and outdoor silos, big bag and octabin systems, error-prevention tools and automated bulk loading control.
Storage containers
Standard material bags can be emptied into storage containers that feed processing machines via side suction to the IMM hopper. The range includes 10 different sizes to align with required material throughput and reduce manual interventions.
Available options include:
- bag-breaker screen
- level sensors
- star magnetic separator
- multi-way suction valves
CS, storage containers
Indoor and outdoor storage
For indoor applications, Silbox compact modular storage silos are made of stainless steel for granular materials, with capacities from 400 to 50.000 dmc. The series comprises 24 Uni single-chamber and 24 Twin double-chamber models. A bag-breaker screen can be fitted to facilitate emptying of bags or big bags. Materials stored in Silbox can be connected downstream to automatic conveying for machine feeding.
SILBOX, modular silos
For in-outdoor use, cylindrical stainless steel silos are available with removable lid and one-way suction valves, covering 1.800 to 30.000 dmc.
Available options include:
- cone with 60° inclination for poorly flowing materials
- Europa version support frame with parapets and connecting walkways
- level sensors
- bridge-breaker system with pulsed suction valves
- thrust loading system
Big bag and octabin handling
Baggy is intended for non-hygroscopic granules such as polythene and polypropylene. A large support frame allows complete emptying without material loss. The modular frame can be disassembled and stacked after use to save space.
BAGGY, big bags unloader
For emptying 800–1.000 kg and 1.500 kg big bags, the SBB big bags unloader can be loaded by forklift or lifting crane. It features a large granule collection tank, a suction valve and a safety ring for controlled opening of the bag spout. A version for flakes and regrind includes integrated shakers and safety protections.
Available options include:
- pulsed suction probe
- forced fluidification
- lower bridge-breaker for flakes
- capacitive and, or vibrating level sensors
Fillbag supports filling of big bags with granules, regrind or flakes, including temporary storage for transfer to another site. An inflation system keeps the bag open to streamline filling. Options include bag weighing on pallet and a printer for reports or weight labels.
Oktobag is designed for complete big bag emptying. Using a floating arm motion referred to as the Wave system, granules are directed toward the centre of the bag, where a suction probe recovers material efficiently while preventing loss. The system can also empty octabins by acting on the inner polythene bag to facilitate discharge. Three versions are offered: Blue with manual movement and control, Sky with programmable arms and Lux for medical applications. An optional empty-bag detection valve signals when discharge is complete.
OKTOBAG, octabins & big bags unloader
Oktomatik, a patented unloader, enables emptying up to 15 octabins per hour (one every four minutes), suitable for high-throughput transfer of granules to a larger silo connected to automatic conveying. It can handle octabins with up to 1.500 kg of hygroscopic materials or technical polymers. The inner polythene bag protects contents from environmental contamination and avoids granule dispersion.
Tilter is a tilting platform for emptying gaylords and, or octabins from 500–600 kg up to 1.000 kg. Granules are extracted by suction while the probe remains submerged. As the level drops, the platform tilts the container, directing remaining material to a bottom corner for complete emptying without operator intervention.
TILTER during sloping phase
Preventing material mix-ups
To reduce the risk of feeding the wrong material, Daily Bins containers are offered with interlocking lids and RFID identification. The lid unlocks when a barcode or QR code reader recognises the same code stored on the container’s tag, allowing only the correct granule to be loaded. The containers are available in 10 sizes. After loading, a tag with the material name is attached. A network-connected RFID reader verifies that the identified material matches the programmed specification and authorises transfer to the IMM. This workflow minimises manual interventions and frees operators for quality-focused tasks.
Silcontrol for bulk deliveries
For plants supplied in 25‑tonne batches by road or rail, Silcontrol manages silo loading and material verification. Upon delivery, the operator scans the barcode on the delivery note. Silcontrol verifies that the identified material matches the order and checks the target silo capacity to confirm it can receive the full load. As an additional safety step, the system opens the selected silo’s loading hose inlet and waits for hose connection. A final electrical signal confirms connection, then the safety valve opens and a signal is sent to the tanker compressor to begin unloading. The company notes that the system is designed to prevent costly loading errors and is particularly relevant where consumption rates reach 2–10 tonnes per hour.
SVS 800 automatic bag unloader
The SVS 800 is an automatic machine for emptying plastic granule bags. It accepts a full 1.000 kg pallet, opens the bags and transfers granules to an indoor silo, then sends material to processing. The system is CE and Industry 4.0 compliant and can empty up to 800 bags per hour. It includes a bulk granule collection system designed for a push conveyor, an empty-bag compression option and a pallet stacking device. By containing pouring operations, the SVS 800 is designed to recover 100 percent of the raw material.
SVS, bag unloader
The applications above illustrate how controls for granules, powders and flakes can be shifted from manual steps to digital systems for day-to-day management. According to the company, these storage solutions are exclusive to Moretto and are aimed at creating added value by optimising processes with durable, high-performance systems.
