- THE MAGAZINE
Moving raw and processed materials through the production process is a vital aspect of ceramic manufacturing, and problems in materials handling can be crippling. Conveying powders and granules in a dedicated pipe system through the use of a vacuum is a well-proven, safe and simple method, and a new line of vacuum conveyors* offers high-performance, energy-efficient and automated material handling in a variety of manufacturing environments. The newest generation of vacuum conveyors are designed for the transportation of virtually all types of materials, including flakes, pellets and powders.
*IC Series, developed by PIAB and available domestically from PIAB USA, Inc., Hingham, Mass.
Conveying PrincipleThe new system operates on a simple seven-step process. Vacuum is generated by a compressed air-driven vacuum pump, which can be controlled automatically. Since it has few moving parts, the pump is virtually maintenance-free. The bottom valve is closed, and a vacuum is raised in the container and the conveying pipeline. From the feed station, the material is drawn into the conveying pipeline and then on to the container. The filter prevents dust and fine particles from being drawn into the pump and escaping into the surroundings.
During the suction period, the air shock tanks are filled with compressed air. When the material container is full, the vacuum pump is stopped. The bottom valve opens and the material in the container is discharged. At the same time, the compressed air in the filter tank is released and cleans the filter. When the pump is restarted, the process is repeated and a new cycle begins. The suction and discharge times are normally controlled by pneumatic or electrical control systems.
Featuring patented multi-stage ejector technology**, the new system consumes less energy than other compressed-air driven technologies. The greater the distance between the vacuum source and the point of use, the more energy is consumed, therefore increasing the cost of production. The multi-stage ejector technology allows for small compressed-air-driven vacuum pumps to be placed directly at the point of use, associating a single pump with each terminal device or small group of terminal devices. By eliminating all tubing between the vacuum generator and the point of use, the ejector cartridges significantly improve performance and save energy.
The new vacuum conveyors feature a compact design that conserves floor space that would have otherwise been occupied by larger machinery. Additionally, material conveyed with the system can be transported by pipes or hoses to provide users with extra flexibility. The vacuum conveyors can transport up to 2 tons of material per hour, depending on the conveying distance and the size and type of material being handled.
**COAX®, patented by PIAB.
Application ExampleEuroelettra, a producer of automatic systems for weighing and dosing applications, recently delivered a cost-effective and reliable dosing system that safely transports the thin colored metal oxide powders commonly used in ceramic tile production.
In order to meet the growing demand in the ceramic tile industry for automated, reliable material handling solutions, Euroelettra decided to include the new industrial vacuum conveyors in the design of its dosing system. "Because production in the tile industry never stops, it is critical to have a conveying system that can operate reliably and without interruption," says Marco Cottava of Euroelettra's R&D department. "This also translates to increased cost efficiency as downtime is reduced."
After the tile's base material is produced inside a spray dryer, it's light brown, and the metal oxide powders are added according to the proper recipe to reach the desired color. The vacuum conveyor system transports the powders from a bag and feeds the dosers that are used to create the recipe. After mixing, the colored powder is conveyed to the presses that produce the raw tile.
The new conveyors' simple design enables them to run successfully with minimal stoppages. "The filters are easy to replace and no time is spent on cleaning out spare parts," says Cottava. "This has dramatically decreased downtime and increased productivity for our customers, all of whom have been completely satisfied with the new solution." Euroelettra's customers also appreciate the fact that the conveyors interface easily with existing control systems.
Another factor in selecting the new solution was its ability to handle ceramic powders that are traditionally difficult to transport. The vacuum conveyors enable Euroelettra's customers to efficiently convey up to 2000 kg of ceramic powder per hour.
Safety was also of primary concern. Metal oxides can be considered toxic, and, in many cases, the metal used to produce the oxide is quite heavy. Since all of the material that is transported with the vacuum conveying system is sealed inside pipes, no powder is released to the surroundings. In addition, with the previous system, the operator had to take the powder from a bag with a bucket and manually fill the doser hoppers. Since the dosers are located over the mixer, the operator was working 10 m from the ground, right over the press and quite near (less than 10 m from) a dryer that operates at around 450°C.
In addition to continuous reliability and safety factors, Euroelettra's customers have also benefited from an increase in product quality. "The new conveyors supply an even amount of powder to the dosing machines so the color of the completed tile products is now more consistent, which has increased product quality for our customers," says Cottava.
For more information about conveying ceramic materials, contact PIAB USA, Inc. at 65 Sharp St., Hingham, MA 02043; (800) 321-7422; or visit www.piab.com. Euroelettra's website is located at www.euroelettra.it.