Abstract: A process of regenerating polluted thermal swimming pool waters is disclosed. The process includes making a condensate of pure thermal water by concentration of the thermal plankton by means of known physical processes: filtering the polluted thermal water and then sterilizing it; regenerating the sterilized thermal water by adding condensate thereto in sufficient proportion to restore the natural population of thermal plankton.

Abstract: The invention relates to a drilling head connection specifically designed for reverse circulation operation and the connection can be screwed on a double pipe system in such a way that the drilling fluid injected into the annular space passes through the annular channel and thereafter through the channel of the drilling head so as to lubricate the leading surfaces of the bit and the plug moves up through the inner space with the excavation material passing through the lateral channels and also the connection can be used with any drilling head.

Abstract: The present invention relates to a system for automatically recovering the entirety of the excavated materials in the order in which they are raised to the surface.The excavated materials being delivered through the central passage of a double pipe system pass into a strainer pipe 6 discharging into a perforated recovery sheath 5 which is closed at its base. A decompression sleeve 3 encloses the strainer pipe. Air and water are evacuated through the strainer slots 6 and all the excavated materials are deposited at 5 in the order in which they are brought up.The invention is applicable to any reverse circulation drilling system.