Bulk Bag Unloader/Screener Automates Pharmaceutical Powder HandlingTURNERSVILLE, NJ—A dextrate binder found in various tablets, Emdex® is shipped in powder form to a pharmaceutical company that uses it in a pain medication for cancer patients. Before adding the powder to the formulation, the company removes oversize particles using a fine mesh screen.
Previously, workers scooped powder onto the surface of a rectangular screener, a manual process that required lifting, generated dust and limited productivity.
The pharmaceutical company turned to Industrial Equipment and Design Company (IEDCO), Turnersville, NJ, which designs, manufactures, and installs custom powder-handling systems. For this application, IEDCO designed a bulk-bag unloading system to scalp oversize granules and then meter a predetermined amount of on-size material into a container.
The system consists of a pair of 23 ft (7 m) high column lifts (to eliminate any platform or mezzanine) and a bulk bag unloader/screener cart measuring 42 in. (1070 mm) square by 92 in. (2340 mm) high. To start the process, a bulk bag of powder weighing approximately 1 ton is attached to a lifting arm on one of the columns. This arm travels up the column, pivots, and deposits the bag on top of the cart, which is connected to a carriage lift attached to the other column. Plant personnel then release the bottom of the bag to access the bag spout, which is inserted into the cart's containment system, where an inflatable seal creates a dust-tight connection between the bag and cart.
The lifts then raise and position the bag and cart in tandem over a container, which can be a 320 gal (1200 liter) intermediate bulk container (IBC) or a 30 gal (115 liter) drum. The container rests on a scale that measures the net weight of powder. At the highest dispense position, the bottom of the sifter cart is 73 in. (1850 mm) above the plant floor, while IBCs used in the process are 69 in. (1750 mm) high. Between the cart and container is a flexible polyurethane connection and butterfly valve, which regulates the flow of powder. When the material in the container reaches the specified batch weight, the valve closes and the container is disconnected from the cart.
Below the cart's containment system is a 30 in. (762 mm) diameter FLO-THRU™ VIBROSCREEN® circular vibratory screener from Kason Corp., Millburn, NJ, which uses multi-plane inertial vibration to separate oversize particles from the rest of the material. The low-profile unit has two gyratory motors mounted externally on opposite sides of the screening chamber. Besides minimizing height requirements, the design positions the bottom outlet directly below the inlet, allowing material to fall vertically through the screener and into the container in a straight-through path at high rates. "The design would have been very cumbersome, as well as taller, had we used a standard circular vibratory screener with side-mounted discharge," notes Ed Heller, president of IEDCO.
The FLO-THRU screener's spring-mounted screening deck vibrates in vertical and horizontal planes, with vertical vibration causing on-size particles to pass through apertures in the screen, and horizontal vibrations causing oversize particles to move across the screen in controlled pathways before exiting through a side discharge spout. All material contact surfaces are of 316 stainless steel or other FDA-approved materials, says IEDCO project engineer Joe Wirzburger.
For consistency with screens used in other plant operations, the pharmaceutical company specified a 30-mesh screen for the FLO-THRU screener. To prevent screen blinding, IEDCO added a Kason ultrasonic anti-blinding device in the center of the screening deck, which transmits ultrasonic frequencies that dislodge near-size particles from screen apertures.
The bulk-bag unloading system contains dextrate powder as it moves from bags to the screener to bulk containers or drums, reducing material waste and eliminating contamination of the product and plant environment, helping the company meet FDA cleanliness requirements, notes David Ryan, IEDCO's marketing director.
The automated system also increases capacity while eliminating the possibility of injury related to manual drum handling. "Now they don't have to lift anything or do any type of manual work," says Jason Heller. "They just press a button and everything happens automatically."