Closing bags of powder and bulk material: A review of basic system options
Until the mid-1940s textile bags filled with agricultural and industrial products were typically closed by tying, wiring, or hand sewing. A packaging revolution began when the bag-closing sewing machine was introduced. Sewing speeded the packaging process and allowed paper bags to be used. However, these early sewing systems required delicate adjustment.
Today's sewing systems sew different bag materials interchangeably without critical adjustment. In addition, you can select from many bag types, including textile, single and multiwall paper, multiwall paper/poly, woven poly, and film poly. You can also select closing options that don't require sewing, such as closers for pre-glued, pinch-bottom paper bags; folders/closers that use hot-melt glue; packers for valve bags; and heat sealers for polyethylene bags. Many of these systems incorporate photoelectric sensors, electronic heat control circuitry and other sophisticated features to improve the productivity and dependability of bagging operations. Each type of bag-closing system offers its own combination of advantages and limitations; selecting the optimum system depends on a number of factors. This article reviews the major options in bulk material packaging and briefly discusses the characteristics of various bag-closing systems.