Processing Magazine

Aero mechanical conveyor assures consistent flow of acrylic powder at Soliant

September 18, 2007

An Aero Mechanical Conveyor (AMC) from Spiroflow Systems Inc. has been instrumental in assuring a consistent flow of soft acrylic powder into a large cylindrical mixing vessel without lumps or sticking in the production of Fluorex™ thermoplastic paint at Soliant LLC in Lancaster, SC. Spiroflow is located in Monroe, NC, 35 miles from Soliant’s Lancaster plant.

Fluorex™ is an alternative to traditional paint and plating systems and is more durable, cost effective and environmentally friendly. With a current production palette of over 140 different colors, Soliant thermoplastic decorative film and coating is used by a variety of industries from automotive to marine, architectural, signage, appliance, electronics, telecom and others. In the automotive industry, Soliant film is used on 20 different car and truck models. Before purchasing the Spiroflow Aero Mechanical Conveyor in the early 2000’s, Soliant employees manually pushed 275-pound drums filled with acrylic resin powder to a scale for weighing and adding to the mix. Once weighed out, two employees manually scooped 1.5 pounds of powder at a time from the drums to the mixing vessel, the beginning stage of the Fluorex™ process. The scale was used to ensure that only the amount of powder specified in the mixing process for that particular paint be added to the mixing vessel. In the vessel, the powder was stirred into a mixture about the thickness of mayonnaise.

Before scooping into the mixing vessel, employees first had to hand-inspect the contents of each drum and physically break up any lumps or sticky powder. Speed and consistency varied from application to application. Each application required an average of 25 minutes per employee or almost a man-hour hour for each operation.

“The manual system was time consuming and didn’t provide the quality control we needed,” noted Mark Beard, Staff Product Development Engineer for Soliant. “We needed a dependable, hands-off system that assured batch to batch consistency and automatically provided a consistent speed and material flow.”

Beard researched and ultimately recommended the portable Spiroflow Aero Mechanical Conveyor based on an advertisement he saw in a trade journal.

“We had no knowledge of Spiroflow’s capabilities, even though they were in our backyard,” noted Beard. “After visiting their facility, we were convinced that Spiroflow had the know-how and expertise we were looking for. A demonstration using our powder convinced us that their equipment was right for the job.”

Designed and custom built for Soliant by Spiroflow Systems, the all stainless steel Conveyor and Distribution system consists of an inclined 90-in. long straight-line Aero Mechanical Conveyor with a sack tip hopper at the inlet.

The Spiroflow system is mounted on a mobile frame complete with two fixed and two swivel casters. The casters assure easy positioning and have locking brakes for maximum safety. When required to add material to the mixer, the mobile conveyor is positioned on to a 4 x 4 foot weight platform that is sunk into the floor so that its top is flush with the factory floor.

Once located on the weigh platform, the weight of the conveyor is tared so that the precise amount of acrylic powder can be loaded into the conveyor feed hopper. The powder is tipped into the hopper through a plastic strip curtain located at the front of the dust hood above it. The dust hood is connected to a dust extraction system that assures an environmentally safe dust free operation. A grid across the top of the hopper is used to break up any agglomerates of material, a main concern with the previous procedure.

A rotary valve controls the rate of flow from the hopper to the conveyor. Six air operated vibratory pads strategically placed around the hopper ensure a consistent flow of powder into the rotary valve at the hopper outlet without bridging. The conveyor has 3 in. conveying tubes and operates at a 45-degree angle. An air motor powers both the conveyor and rotary valve. This is common in hazardous environments. An inner-locked access panel facilitates cleaning of the internal conveyor components and a vision panel in one of the conveying tubes enables operators to determine when cleaning is required. The conveyor systems consist of several evenly spaced polyurethane disks attached to a wire rope. The rope and disks travel in a continous loop fashion at a consistent high speed within parallel steel tubes. At each end, the rope assembly runs from one tube to the other around specially designed sprockets. One of the sprockets drives the rope and disks while the other provides tension to the rope. By maintaining the rope and disk assembly at a constant high speed, the conveyor produces an air stream that fluidizes and conveys product to the mixing vessel where the powder is centrifugally ejected. This method of conveying action allows varied production capacities from high to low with low energy requirements and minimal production degradation and separation.

According to Beard, the problem of lumpy, sticky powder has been eliminated, making it a virtual a worry-free operation.

“It’s a quality worry free piece of equipment we are glad to have,” noted Beard. “Pouring into the vessel is consistent and we find the system extremely dependable. Instead of over an hour in labor required under the old method, the same process takes under 20 minutes, is totally automatic and requires little or no supervision.

Beard added that the system is virtually maintenance free. In the over five years since installation, the only routine maintenance required relates to cleaning and rope tensioning, he said, and Spiroflow’s after sales team has been excellent in providing us with required support.