Bulk Bag Filler and Bulk Bag Unloader: Automated, Single-system Process Operation
This bulk bag filler system; receiving input material from an integrated bulk bag unloader, an integrated bag dump station, and a vibratory conveyor system, enabled the material processing operation to effectively transition to an automated, 20,000 lb./hour, bulk bag filling process from a relatively low-capacity, operator-intensive, 50 lb. bag filling system.
Multiple materials, all with differing characteristics, including: fast-flowing, dusty, sticky, and static-charged, enter the process operation based on the specific recipe selected at the system HMI by the operator. The NBE bulk bag unloader, receiving bulk bags of severely agglomerated material, starts an integrated, automated material conditioning sequence, including: massage paddles with 2,200 lbs. of paddle pressure, and an agitator hopper to prepare the material for supply, via screw conveyor, to the bulk bag filler. For secondary ingredients, a bag dump station, integrated to the bulk bag unloader, enables manual introduction of material to the agitator hopper for conditioning, blending, and supply to the bulk bag filler. The primary ingredient, supplied from downstream pneumatic conveying, is introduced to the bulk bag filling process through a 24” wide, 304-2b stainless steel, vibratory conveyor with a total material supply capacity of 20,000 lbs./hour.
This automated, bulk bag filler and bulk bag unloader system was built to be compliance-ready at start-up and to conform to the specific, regulated processes and practices of the Class II, Div. 2, Group G process area, as well as explosion protection and control features for venting, directlng, and releasing overpressure. NBE was the single-source provider of the system’s controls and automation, and was singularly responsible for integration of the system controls to the facility’s supervisory control and data acquisition system (SCADA). This NBE bulk bag filler and bulk bag unloader system significantly increased line capacity, improved resource management, reduced operating burden, increased labor efficiency and safety, and extended equipment contribution and performance lifecycles.
Bulk Bag Unloader with Explosion Protection Design Controls Combustible Dusts; Polycarbonate Enclosure Protects Process Area
Perhaps one the most significant factors contributing to the danger of combustible dust in the workplace is what goes unknown to production and maintenance staff. Consider this, the U.S. Chemical Safety Hazard Board (CSB), in reviewing the MSDSs of 140 substances known to produce combustible dusts, found that 59% of the MSDSs did not state hazard information specific to the combustible dust, or did not place the hazard information on the MSDS in a manner clearly recognizable by the worker. The CSB also found that the remaining 41% of the MSDSs presented poor or inadequate information regarding the potential hazards of the dusts. So, how can processing and packaging operations that handle dry bulk materials protect themselves from hazards they may not even know exist? The answer may lie in machine design that proactively incorporates protection from, and prevention of dusting of combustible materials.
This bulk bag unloader system, manufactured by National Bulk Equipment (NBE),
Bulk Bag Unloader with Explosion Protection Design Also Reduces Combustible Dust Escape
uses protective and preventive machine design elements to significantly reduce the level of airborne contaminants migrating into process areas. A proactive protection element in this design is a 9.525mm, polycarbonate encasement surrounding the bulk bag unloader. This protective element works to control dusts that piggyback on the exterior of bulk bags from becoming airborne and entering the work zone during bag conditioning and bag collapse. A proactive prevention element of this design is the E3(tm) closed-cycle dust recovery system. The E3(tm) secures and encloses the bulk bag spout within a sealed containment cylinder. The combustible material is introduced, dust-free, through the E3(tm), directly to an integrated surge hopper. The NBE surge hopper is constructed with explosion protection and control features, including: an explosion venting system, calculated on a Kst value of 170 and a Pmax of 9.5, to direct and release overpressure to prepared areas. The hopper construction includes reinforced walls and a reinforced cover, and is rated for 4.5 PSI internal pressure.
Bulk Bag Fillers Process Combustible Dry Powder Material
Here is a unique bulk bag filler application in a process where high volumes of combustible powders are present. Three bulk bag fillers, each being fed by a 1,060 cubic foot capacity storage vessel, process up to 17,000 pounds per hour of the combustible powder. The process area is defined to include Class I, Division 1, Groups C and D; and Class II, Division 1, Groups F and G. The bulk bag fillers are being filled with materials of various characteristics, including flakes and rods. Integrated bulk bag densification ensures a full and stable finished bulk bag, regardless of material type. An integrated, NTEP-certified weigh system bulk bag filler for combustible dust-generating application ensures the bags are filled to a weight of +/- .01% of the total bag weight, up to 4,500 pounds. The bulk bag filler process system manufacturer, National Bulk Equipment, Inc., designed and built the system-wide automation and equipment controls to centralize to a single, menu-driven HMI. The entire process operation communicates directly to the facility's SCADA center.
National Bulk Equipment implemented rigorous risk assessment procedures to ensure the bulk bag fillers would work to prevent operator hazards and improve the physical ergonomics for the operator.