Bag slitter

A labour-saving device that is sometimes used with the bag slitter, and other small operations equipment, is the vacuum bag lifter (see Figure 7.6). A suction nozzle of a similar diameter to the width of the bag is connected to a vacuum pump, and when the pump is activated the force on the bag is sufficient to lift the bag from pallet to feed conveyor, but not sufficient to break the bag. This greatly assists with manual lifting of awkward loads, but the necessity of an air supply may be restrictive in some applications. 

An additional option for some types of bag splitter is clean in place (CIP) operation. This is particularly useful for hazardous powders, and/or processes that use the same bag slitter for a number of different powders. CIP operation means that it is possible to completely clean the piece of process equipment without dismantling. 

Figure 7.7 Self-contained bag slitter (WJ Morray Engineering Ltd).

Before using a particular material in either a bag slitter or a bag dumper it is recommended to check with the manufacturer as some hoppers may not be suitable. However, some examples of materials used in these devices are alumina, aluminium sulphate, carbon black, cement, cocoa beans, cocoa powder, coffee beans, flour, hydrated lime, lime, milk powder, potassium hydroxide, silica sand, sugars, talc, titanium dioxide and whole nuts (Aptech (Powder Systems) Ltd 2006 Hexicon Corporation 2006 Palamatic Materials Handling 2006 Spiroflow Ltd 2006 Vibrair 2006). 

WJ Morray Engineering Ltd (2006) Bag Slitters, http //www.morray.com/. Accessed 21 November 2006. Woodcock, C.R. Mason, J.S. (1987) Bulk Solids Handling An Introduction to the Practice and Technology. Chapman and Hall, New York. 

Film thickness is usually monitored during the process. A beta gauge detects the passage of beta rays through the film bubble, while capacitance gauges measure the increase in thickness as increased capacitance. Blown film lines may also include corona or flame treatment to improve adhesion, sealing operations for bags, and slitters. 

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