Open Bag & Valve Bag
- Broadly, there are two main bag types - the open bag and the valve bag. Although the multi-purpose open bag is widely used, the AMO bagging system is designed basically for the valve bag. The reason for this is valve bags have considerable advantages in terms of cleanliness, safety and efficiency. For open-bag filling, the entire top of the bag is the mouth and powder is dropped into the bag from above. In contrast, the valve bag is filled through a valve built into one corner at the top of the bag. A filler nozzle is inserted into the valve, maintaining a closed environment as the bag is filled.With a valve bag, the Packer unit will complete the basic processes of filling; there is no need for secondary processes, such as machine sewing of the bag. Another considerable merit is that the valve bag enables smaller bag dimensions, with a higher fill density.
Types of Valve Bags & Sealing Methods
Inner Sealed Valve Type
The valve is inside the valve bag, and the bag is sealed with an adhesive sealing label. As the valve is inside, the possibility of powder spillage after filling is reduced considerably. The sealing machine covers that sealing label with adhesive and seals the bag. This method eliminates powder spillage after sealing and prevents foreign materials from entering the bag. The AMO system uses the inner valve bag for automated sealing.
Inner Sleeve Valve Type
This is the general name for bags with internal valves. The Inner Sealed Valve Type, above, is one variation of the Inner Sleeve Valve Type. As the bag fills, the powder pushes the valve upward, effectively closing the valve and thereby preventing powder spillage. In other words, simply filling the inner sleeve valve bag prevents spillage of contents.
External Sleeve Valve Type
A bag with an external sleeve valve appears to have a tube extending from the bag. After filling, the bag is closed by folding the external sleeve valve. Adhesive or other sealants are not necessary, and the bag is effectively sealed simply by folding the valve. This valve bag and sealing method are thus often used for manual bagging operations. The valve can also be heat-sealed for complete closure.