Vacuum Degasser - Medical Products Manufacturer

APPLICATION: The Vacuum Degasser is used to purge room air from vials, replace it with oxygen, and then cap the vials with a stopper. This is done as part of a packing process for a bacterial test.

DESIGN: The Vacuum Degasser is an in-line vacuum and pressurization machine comprised of two pairs of lines. Each pair of lines, located on opposite sides of the machine, has a vial conveyor, feed screw, and 24 valve manifold. The vial conveyor and feed screw increase and decrease speed simultaneously to provide smooth transfer through the machine. Each manifold has a separate vacuum supply line and compressed gas supply line in order to provide individual operation. While one side is operating the other side may be cleaned, simple maintenance may be performed, or it may be inspected for quality assurance. The production rate is approximately 300 vials per minute with an upper speed of 350 vials per minute.

SYSTEM DESCRIPTION: The system consists of an infeed conveyor which is designed so that it can accumulate a large number of vials (by circulating them around the table) in the event of some type of slowdown downstream. Vials are fed onto the infeed conveyor via a rotary disk infeed, and then are transferred onto the vial conveyors.

The vial conveyor runs at a slow speed to accumulate vials while the feed screw is not turning and the manifold is raised. When the vials are indexed, the vial conveyor and feed screw are synchronized to provide smooth conveying of the vials into and out of the manifold position. The conveyors and screws will accelerate and decelerate at the same rate. A clamp then extends toward the feed screw to secure the vials during processing. The design of the clamps is such that they will straighten and correctly position vials that are slightly tilted or misaligned.

The manifold lowers to seal the cups onto the vials (the cups are mounted on springs to allow the cups to adjust to the exact height of the vials). Each manifold contains 24 cups used to create a vacuum in the vials, fill them with purge gas, and finally seat the stoppers on them. A pressure transmitter monitors the pressure inside the vial/cup chamber. During normal operation the manifold has two positions: raised and lowered. A third position is available to raise the manifold higher than normal for easy access during cleaning or maintenance procedures.

The clamps, plunger, and manifold are then retracted to their home position. The vial conveyor and feed screw accelerate to quickly transport the processed vials to the outfeed conveyor, and bring unprocessed vials into the vacuum degasser. If a group of vials is out of the preset pressure tolerance, a diverter extends to redirect the vials to an inspection station. The outfeed conveyor, which is also designed to accumulate vials, moves the processed vials out of the machine and transfers them to the next step in the production process.

The control system for the vacuum degasser features an Allen-Bradley SLC 5/04 processor. The SLC communicates to two DC motor drives on the vial conveyor and two stepper controllers for the feed screw indexers. Potentiometers are used to adjust the high and low speed settings for the vial conveyor. An eight-inch color screen operator interface with a function key membrane pad is used to access operational parameters and diagnostic information.