A new line of vacuum conveyors can decrease
energy consumption and downtime for a number of ceramic materials handling
applications.
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 Principle
The 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.

The vacuum conveyors can transport up to 2 tons of
material per hour.
Application Example
Euroelettra, 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. Links