If foundry processes with sand offer the possibility to save not only costs but simultaneously to do something for the environment, there is no reason why these advantages should not be taken. This at first sight rather simple realization represents the starting point of HENSEL GMBH, a company of the ROTAMILL GROUP, highly specialized in the fields of conveying and foundry techniques for many years. Or to be more specifically, the company located in the SIEGERLAND manufactures innovative mould plants and sand recovery installations employed and used in foundry works.
The benefit for the customer is obvious: After the casting process, the remaining sand can be re-used at almost 100 %. Only a small quantity of new sand has to be re-added. "This results in a considerable savings of material costs and also reduces the incurred disposal quantities"; Mr. Matthias Hensel, managing director, explains.
"Moreover, the principal of the firm continues, "thanks to the employment of the special custom-made sand recovery installation the sand quality is considerably improved which has an effect on the surface of the cast part and as to the reduction of the loss of ignition. Due to their compact dimensions the HENSEL plants can be integrated in almost all foundry processes.
In order to permit prospective customers to convince themselves of the advantages of the HENSEL installations a pilot plant has been built which is available at the Siegen workshop. According to Mr. Matthias Hensel, depending on the type of sand and the binder systems, a recovery process for one ton of sand takes between 2 and 20 minutes.
This is how it works: After the casting process the sand is first ground and thus brought to its original grain size. After that the sand is separated from impurities and remaining resin parts. By means of an integrated grater device the grains are cleaned from the remaining binder means. By help of two shafts working in opposite directions and equipped with rubbing rails, the sand is accelerated and the rubbing process is initiated. In order to be able to suck off the rubbed off binder remains, the chamber bottom of the plant is equipped with nozzles through which the air produced in a fan is blown in. The fan starts automatically. At the sand intake chamber there is a connecting piece which has to be connected to a filtration plant. The regulation of the required air quantity is finally done by help of a regulation valve, the pressure regulation by help of a vacuum valve. The sand in- and out-take is controlled by a
Electro-pneumatically regulated slide bar. After the rubbing and once the cleaning process will have been terminated, the sand only has to be possibly transported to refrigeration. "Finally a sand quality is obtained which was brought in principle to a new sand quality", Mr. Matthias Hensel comments enthusiastically. Who wants to test the pilot plant of HENSEL GmbH is of course invited to do so.