A fresh approach to ingredient blending

A producer of bath and body products, fine fragrances and personal care products has been able to bring the blending of ingredients for its Spring Fresh body powder in house, with the addition of a 3m Flexicon screw conveyor and mixer. The equipment has been added to an established Flexicon bulk handling system at the New York manufacturing facility of Delagar Division, Belcam. This has meant savings on the purchase of blends from a contract manufacturer and the cost of shipping them to the plant for packaging. Also, Delagar now has greater control and flexibility to modify formulations to satisfy individual customer requirements.

The Spring Fresh product is a blend of talc powder, glitter and fragrant oil. Prior to the plant upgrade, raw talc was shipped from the mine to a contract manufacturer where it was blended with glitter and fragrance, loaded into bulk bags and shipped. Once at Delagar, the material was discharged by a bulk bag unloader into a 4.5m long flexible screw conveyor that fed a packaging line.

Bringing blending in-house

Now, raw talc now arrives at the plant in 900kg bulk bags, the straps of which are attached to a bag lifting frame that is fork lifted into cradle cups atop the 4.6m high telescoping posts of the original Flexicon Model BFF Bulk Bag Unloader.

The operator pulls the bag spout through an iris flow control valve positioned at the top of a hopper intake chute, and then closes the valve. This allows the spout drawstring to be untied and the valve opened slowly, avoiding uncontrolled bursts of material into the hopper and dust into the plant environment. Spring-loaded Pop-Top bag extension devices on each of the frame posts stretch the bag upward into a cone shape as it loses weight to promote discharge of material through the spout. Additionally, Flow-Flexer bag activators raise and lower opposite bottom edges of the bag into a steep ‘V’ shape to loosen compacted talc and promote total discharge through the spout.

Delivering preset amounts

The new Flexicon 3m long x 11cm diameter flexible screw conveyor moves talc from the unloader to the new 1.12m3 horizontal paddle blender. As the conveyor discharges talc into the blender, a liquid metering pump, for the liquid fragrance oil, and a bulk solids feeder, for the powdered glitter, deliver small preset amounts of the two materials continuously into the blender while it is running.

During the 8 to 12-hour continuous run cycle, the blender automatically discharges the blended batch into a 0.028m3 surge hopper that charges the original 4.6m long flexible screw conveyor, which discharges into the surge hopper of the packaging machine.

Level sensors

Both hoppers have high/low level sensors to signal a controller that activates the flexible screw conveyors to maintain fill levels. The level sensor on the hopper below the unloader also alerts the operator to replace empty bags. The same volumetric system controls the motors that meter glitter and fragrant oil into the blender.

Raw talc powder is soft and dusty “much like flour,” said Delagar’s production manager, and must be handled by the machinery quickly and lightly so as not to become too aerated. She adds that the addition of glitter and fragrance oil has little effect on the powder’s flow characteristics.

Minimising talc compression

The flexible screw conveyors are equipped with spirals which are designed to handle the aeratable powder, while minimising compression of the talc which could pack and cake under excessive pressure and frictional heat.

“Between production runs, an operator vacuums what little powder remains in the blender,” said the production manager. The bottom end cap of the conveyors can be removed and the screws rotated in reverse to evacuate the tubes. She concluded: “The flexible screw conveyors do not leave enough residue to concern us.”