Big bag discharging systems include a wide range of components to accommodate a broad range of applications. Polimak’s big bag discharging systems are available in two main configurations: upper frame models and holding platform models..
Upper Frame Models of Big Bag Discharging System
Open Top Big Bag Discharge Station
As the simplest configuration, the unloading system can operate without an upper frame. This design is suitable when big bags are delivered by forklift or overhead crane.
In this configuration, the big bag is placed onto the discharge hopper using a forklift or crane. This configuration is ideal for handling easy-flowing dry bulk solids such as grains, fertilizers, and free-flowing granules. These materials are discharged smoothly through the big bag's bottom spout directly into the hopper, ensuring efficient and consistent flow.
An additional option available is the installation of pneumatic pistons on the side frames to assist in emptying the big bag. These pneumatically actuated massage cylinders apply side pressure to the big bag, helping to loosen compacted material. This massaging system is especially effective when the bulk solids have become compressed during storage, as it avoids the further compaction that vibration aids can cause and promotes a more uniform discharge.
Big Bag Discharger Upper Frame With Big Bag Hanging Unit
In this model, overhead cranes or forklifts transport the big bags to the discharge station; the bags are then suspended on the hanging unit for secure and controlled unloading.
A lifting cross is placed over the big bag, and the straps or handles of the big bag are fixed to the hooks of the lifting cross. The crane or forklift then lifts the big bag along with the lifting cross and places it onto the upper frame hanging unit.
According to the needs of the application, an optional spring and damper mechanism can be included to apply upward force to the lifting cross. As raw material begins discharging, this mechanism moves the big bag upward, assisting in the product discharge. Additionally, side massaging pistons and a big bag vibration motor can be used to speed up the unloading process.
Big Bag Discharging Station With Hoist
In some applicatios, an electric hoist is installed at the top of the upper frame to assist with lifting and positioning big bags. This monorail hoist travels horizontally along an I-beam-shaped trackway integrated into the upper frame, allowing for smooth and precise movement.
The operation of the hoist system begins when big bags placed in front of the discharge station are securely lifted and carefully positioned onto the big bag platform for unloading. During the discharge process, the hoist maintains tension on the bag, holding it in place and assisting with a steady, controlled flow of material.
Optional features such as side massaging pistons and a big bag vibration motor can be integrated into the system to improve unloading efficiency. These additional equipment are especially beneficial for loosening compacted or cohesive materials, ensuring a consistent and uninterrupted discharge—particularly in the case of fine powders or poorly flowing solids.
Big Bag Holding Platform Models
Big Bag Holding Platform with Hopper and Side Access Door
The holding platform consists of a rectangular table with a circular inlet, covered by a rubber seal, and a conical hopper at the bottom. The rubber seal prevents dust leakage from the bottom of the big bag during unloading and ensures proper airflow to the dust collection unit. The bottom hopper is equipped with a side access door, allowing the operator easy access to the big bag discharge spout. The operator can untie the spout or cut the bottom with a knife and then close the side access door of the hopper.
Another essential component of the system is the dust collector, which is designed to extract airborne particles during the discharge process and maintain a clean, safe working environment. A vibration motor installed on the hopper aids in the discharge of big bags. Optional cutting blades can be installed in the middle of the rubber seal. When the big bag is placed on the platform, these blades cut the bag instantly, promoting faster flow. This platform design is ideal for high-capacity big bag handling operations.
Big Bag Holding Platform With Dust Tight Docking Station
A dust-tight seal with the big bag discharge spout is provided by the docking station. It effectively eliminates dust emissions and contamination during the discharging process. To be able to clamp and seal the discharge spout, a manual or pneumatically controlled clamping mechanism is used. This mechanism moves vertically and is adjustable to accommodate different big bag sizes. Once the big bag's inner liner or bottom spout is clamped, the operator unties the bag, and product flow begins. The dust collection system ensures no dust is emitted in the working area.
To regulate material flow through the discharge spout, our custom-manufactured iris valves can be added as an optional component. The iris valve is positioned between the big bag holding platform and the docking station, with the discharge spout passing through it. The iris valve can be controlled by either a pneumatic piston or a manual handle, allowing for adjustable unloading speed.
These valves are typically actuated by pneumatic actuators and are used to automatically open and close the product flow to discharge material to downstream equipment.
Installed below silos or hoppers, these valves are used for maintenance operations of equipment such as rotary valves, screw feeders, etc., that are positioned below the butterfly valve.
These valves are typically actuated by pneumatic actuators and are used to automatically open and close the product flow to discharge material to downstream equipment.
In this design, the butterfly valve is sandwiched between two flanges. Rubber sealing at both faces of the valve provides a tight seal between the flanges and the wafer butterfly valve.
One side of the valve has a bolted flange connection, while the other side features a built-in short pipe designed for fixing a flexible sleeve.
These valves have bolted flange connections on both sides, making them suitable for installation on silos, hoppers, screw feeders, and similar applications.
Bulk tanker trucks or open trucks can be filled with powdered materials delivered within FIBC bags. These systems generally consist of bulk bag discharging station, mechanical or pneumatic conveyor and loading bellow. Big bag discharge station transfers the bulk solid from big bag to conveying system. Conveying system transfers it to truck loading area. And loading bellow is used to fill tanker truck without any dust emission. Since truck loading operations are done within limited time, high capacity big bag discharge systems and bulk material conveying systems are used. For short distances, screw conveyors are preferred to transfer material from big bag discharge station to truck loading chute. For long conveying distances, pneumatic conveying systems provide better service. There may exist a storage hopper or silo above bulk truck loading bellow to compensate material flow between inlet and outlet. Bulk bag discharge and truck filling systems have automatic control system that monitors product level in truck and operates all equipment accordingly. Optional weighing system can be added to measure the amount of material that is filled to truck.
Big bag discharge systems can deliver dry bulk solids in powder and granular form to weighing and batching systems. The loading hopper of the weighing system should remain full during dosing and batching. Big bag discharge systems can monitor the product level in the loading hopper and maintain a constant level automatically. Depending on the dosing speed and conveying distance, mechanical conveying systems or pneumatic loading systems may be used. Dust collectors can be employed to prevent dust emissions during hopper loading, especially for materials with high dust content.
Dry bulk packaging systems are used to fill powdered or granular materials into bags, drums, jars, sacks, etc. Bulk materials delivered in big bags must be transferred to packaging machines without interruption. The loading hopper of the packaging system should remain full during the filling and packaging process. Big bag discharge systems can monitor the product level in the loading hopper and maintain a constant level automatically. Depending on the packaging speed, mechanical conveying systems or pneumatic loading systems can be selected. Dust collectors can be used to prevent dust emissions during hopper loading, especially for materials with high dust content.
Mixer automation systems are used to mix dry bulk solids according to specific recipes. Raw materials delivered in FIBC bags can be transferred to mixing units through a combination of conveying equipment and bulk bag discharge systems. Depending on the type of application, pneumatic conveying or mechanical feeding systems can be used to fill mixers. Big bag discharge stations can be manufactured with built-in dosing systems. The amount of raw material to be loaded into the mixer is automatically controlled with the help of a weighing and dosing system. Dust collectors can be used to prevent dust emissions during the mixer filling process.
Bulk material stored in big bags can be automatically filled into small bags. Big bag discharge systems come with optional built-in bag filling units. For low filling capacities, these units are installed below the big bag discharge hopper, providing a practical and cost-effective solution. Both big bag discharging and bag filling operations can be handled by a single, compact system. For higher bag filling needs, bag filling machines are installed near the bulk bag discharge stations. Pneumatic conveying systems or mechanical conveyors can be used to transfer bulk material from the FIBC bag discharge station to the bag or sack filling system.
Mechanical conveyors can be used for silo loading from big bag discharge stations. Screw feeders, bucket elevators, rotary valves, or chain conveyors are connected to big bag discharge stations to fill silos. The selection of conveying equipment directly depends on the conveying distance, height, transferred material, and capacity. Bucket elevators are preferred for high silos, while screw feeders are preferred for shorter silos and short distances. The big bag discharge system can be installed on top of the silo for faster filling. In this case, rotary valves or butterfly valves are better choices as they provide simple flow control. Dust collection systems may be required depending on the dust content of the bulk solid. During silo loading, air content in the silo escapes to the atmosphere and carries some dust along with it. Vacuum fans and jet filters in dust collectors prevent dust emissions into the environment. The collected dust is sent back to the silo, thus preventing product loss.
Pneumatic conveying systems installed after bulk bag discharge units transfer bulk material through conveying pipelines to fill silos. This configuration is useful in applications where high transfer rates and long conveying distances are needed. In production lines where raw materials are stored in warehouses far from storage silos, bulk bag discharge stations can be installed close to the warehouses, and pneumatic conveying systems are used to fill silos from long distances. This design reduces the need for forklifts and cranes for bulk material transfer on the production site and increases overall efficiency.
Pneumatic conveying systems used for silo loading utilize blower pumps or compressors. Motor power, pipeline diameter, and equipment selection depend on the type of bulk material, transfer distance, silo height, and transfer capacity. Level sensors, jet filters, and other equipment are installed on storage silos to ensure the proper operation of the silo filling system.
Pneumatic conveying systems installed after bag dump units transfer bulk material through pipelines to fill silos. This configuration is ideal for applications requiring high transfer rates and long conveying distances. In production lines where raw materials are stored in warehouses far from storage silos, bag dump stations can be installed close to warehouses, allowing pneumatic conveying systems to transport materials over long distances. This design reduces the excessive use of forklifts and cranes for bulk material transfer within the production site, improving overall efficiency.
Pneumatic transfer systems used for silo loading utilize blower pumps or compressors. Motor power, pipeline diameter, and equipment selection depend on factors such as the type of bulk material, transfer distance, silo height, and transfer capacity. Level sensors, jet filters, and other equipment are installed on storage silos to ensure the proper operation of the silo filling system.
Mechanical conveyors can be used for silo loading from bag dump stations. In this configuration, screw feeders, bucket elevators, rotary valves, or chain conveyors are connected to bag dump stations to fill silos. The selection of conveying equipment depends on factors such as conveying distance, height, material properties, and capacity. Bucket elevators are preferred for high silos, while screw feeders are ideal for shorter silos and short distances. Bag dump systems can be installed on top of the silo for faster filling. In such cases, rotary valves or butterfly valves are better choices as they provide simple flow control.
Dust collection systems may be required depending on the dust content of the bulk solid. During silo loading, air inside the silo escapes to the atmosphere, carrying dust particles with it. Dust collectors equipped with a vacuum fan and jet filter capture airborne dust. The collected dust is returned to the silo, preventing product loss and ensuring a cleaner environment.
The inlet skirt is an optional feature designed to extend the lifespan of the flexible connector sleeve. Its upper portion is attached to the outlet port of the upstream equipment and extends down into the bin activator’s inlet port. The primary function of the inlet skirt is to serve as a protective shield, safeguarding the flexible connector seal from wear and damage.
A vibratory motor is externally mounted to the bin activator. When powered, the motor generates vibrations that facilitate a steady flow of dry bulk materials within the system. Depending on the application requirements, one or two vibratory motors can be installed externally.
To accommodate a bin activator, the cone of a silo must be shorter than usual, resulting in a wider outlet. A flange supplied with the bin activator is separately welded to the silo’s outlet, slightly above the opening, at the production site. Once installed, the vibrating bin discharger is securely bolted to the flange, ensuring a stable and reliable connection.
Special spring suspension links and an engineered polymer seal work together to create a flexible connection between a vibrating bin discharger and the equipment positioned above it.
The proper design and installation of the polyurethane seal prevent it from slipping off and ensure a secure seal, eliminating the risk of dry bulk material leakage. Additionally, the seal offers high stress resistance and long-term durability, withstanding stresses caused by motor vibrations, pressure conditions, and other operational factors.
Externally installed spring suspensions provide full resilience to the vibrations of the cone head. They ensure that the generated vibrations affect only the cone itself rather than the upstream equipment structure.
An internally tapered, conical-shaped baffle plate is positioned at the center of the bin activator’s diameter. The baffle is rigidly attached to the equipment body using structural steel components. It facilitates bulk material flow from upstream equipment by directly inducing vibrations into the material.
A secondary deflector plate reduces the weight of the bulk material in the lower portion of the bin activator by acting as a wedge beneath the material, directing it around the areas adjacent to the cone’s surface.
Polimak baffle plates are available in various configurations, including convex and cone plates, and in different angles (15°, 30°, 45°, or even 60°) depending on the flow characteristics of the handled bulk material and the specific application requirements.
