Vacuum technology puts the gloss on synthetic stone production
08 September 2015
Diresco uses Busch vacuum technology to produce synthetic stone slabs that are completely free of gas inclusions and cavities. Vacuum is applied to the material presses of both production lines, to ensure a top quality appearance and optimum structural integrity.
Founded in 2003, Belgian company Diresco produces synthetic stone slabs from quartz granules and resin. These products are marketed under the brand name 'Diresco Stone' and are used primarily as work surfaces in kitchens, and as wall and floor tiles in bathrooms.
The quartz granules are used to create materials deceptively similar in appearance to stone surfaces. A variety of surface textures can be created by Diresco's processes, from gloss to matt and the company’s heavily textured 'Anticato’ ranges. In comparison to real stone, synthetic stone has the advantage of reproducible appearance – the surface texture is always the same. It is also resistant to water, food acids and food colourings; is scratchproof, non-fading, long-lasting and easy to clean.
After the quartz granules are mixed and blending with the synthetic resin, the resulting material is fed automatically into a mechanical press. To create the perfect surface that Diresco seeks for its products (even the smallest indentations and cavities can become visible after processing), vacuum is applied during the pressing process, the reduced pressure ensuring that surface imperfections cannot form.
Slabs are transferred from the press and hardened in an oven at a temperature of between 100 and 125°C. After cooling they are stored for at least 24 hours before they undergo further processing. Every slab is subjected to extensive quality control examinations before leaving the factory.
Even the smallest air or gas inclusions cannot be tolerated, so vacuum technology plays a major role in the achievement of high-quality products at Diresco’s Opglabbeek plant.
Originally, liquid ring vacuum pumps were installed on the vibrating presses, but these proved ineffective at preventing the formation of all air, steam and styrene vapour inclusions. In 2006, Diresco’s engineers turned to rotary vane technology for a solution to these problems.
Two Busch R 5 rotary vane vacuum pumps with a pumping speed of 1,600m³/h each were installed. These pumps achieve an ultimate pressure of 0.1mbar, which corresponds to a vacuum level of 99.99 percent, a factor that led to substantially increased product quality and a reduction in the duration of the pressing process.
In order to meet increasing product demand, the pressing process was further accelerated by the addition of a Panda vacuum booster, installed before the parallel arrangement of rotary vane vacuum pumps. Diresco was particularly pleased with the performance of this system, and when a new production line was introduced in 2009 an identical Busch vacuum pump configuration was duly installed.
In terms of after-sales service, all maintenance work is carried out by Busch under a service contract. There are only two services per year, although at times the vacuum pumps are in operation 24 hours a day. Servicing is confined to inspection, oil change and filter replacement. All the smaller R 5 rotary vane vacuum pumps used in numerous production handling units are inspected at the same time.
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