The Stott Filling and Weighing System is a unique filling system utilizing a combination of inflatable packing head and a pinch valve feeding system that enables the accurate filling of powders into various kinds of bags or containers in an easy to operate, dust free environment.
There are various types of packing heads optimized for use on wide mouth bags (plastic bags, paper bags, aluminum lined bags), fiber drums or flexible containers. The Stott Filling and Weighing System is used for filling of various powders in the chemicals, pharmaceutical and food industries where powders are used. It is especially suited to improve work conditions in filling operations where dust generation is high, product losses due to removal of dust is high, filling accuracy is bad. For materials that require it, filling in nitrogen or dry air is also possible.
Fig.1 Schematic structure
A dust removal feature is integrated into the expandable packing head. After setting the bag, the expandable packing head is inflated with compressed air sealing the bag prior to filling. The inner diameter of the packing head is constructed to create an optimum flow of air for dust removal. This design also minimizes the flow of material out of the bag and to the dust collector. The effect of the dedusting air on material weighing is minimal. The amount of inflation of the packing head is adjustable with a pressure regulator allowing the use of bags such as paper bags that are easy to tear.
At the end of the weighing sequence, a pinch valve is used for fine adjustment of the weighed material. Just prior to reaching the set weight (for example at 90% of the set weight), the pinch valve closes stopping feeding into the bag. The feeder continues to feed material on top of the closed valve as the material for fine adjustment then stops. The pinch valve slightly opens and a vibrator activates starting the final fine feeding. When the weigh reaches the set weight, the pinch valve closes, completing the weighing sequence. This control function contributes to a very accurate filling. The opening of the pinch valve is adjustable with proximity switches on the pneumatic cylinder.
After filling is completed, the packing head is deflated. At the same time an integrated valve opens increasing the de-dusting airflow. This removes any free-floating particles and deflates the bag increasing handle-ability.
Fig.2 Flow
Used for filling of various powders in the chemicals, pharmaceutical and food industries.
Below is a description of the filling process.
Fig.3 Filling-Weighing process
Filling and weighing system with integrated pinch valve feeding system.
Fig.4 Big bag system BBS
Filling and weighing system for flexible containers. Optional pinch valve feeding system can be installed.
Filling and weighing system for wide mouth bags, fiber drums
For use where weighing is not required. Since the system is operated with just pneumatic equipment without the use of electrical components, can be used where explosion proof equipment is required.
Fig.5 Packing head system PHS
Fig.6 Packing head unit PHU
Fig.7 STS Easy disassembly type
The powder contact parts are easily disassembled for cleaning. Used in pharmaceutical and food applications.
Fig.8 Packing head options
Fig.9 Packing head and support ring
For plastic liner bags for flexible containers with a opening of 600mm diameter or bigger, a packing head support ring is used. The plastic bag is held in place between the packing head and the support ring. The bag may be wrinkled where it is held in place by the packing head, but no powder leaks.
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