Linde Aktiengesellschaft

Dieter Rebhan

Ernst Miklos

Reinhard Strigl

Hartmut Krumpholz

During the production of solid CO.sub.2 pellets by compressing CO.sub.2 snow, in order to reduce the sublimation of the CO.sub.2 snow in the compressing step, the CO.sub.2 snow is subcooled with a cryomedium, e.g., argon or nitrogen. The compression mold may be separately cooled and the CO.sub.2 snow may be subcooled with liquid cryomedium while in a storage vessel and/or sprayed with liquid cryomedium while on a conveyor leading to the press.

Production of CO.sub.2 pellets

A process and apparatus is provided for explosively forming plastic objects from shredded plastic such as recycled plastic having different compositions. The shredded plastic and an explosive gas mixture is introduced into a mold cavity having the shape of the object to be formed, and the gas mixture is ignited, generating sufficient heat and pressure to force the plastic to conform to the shape of the mold cavity. The temperature and pressure in the mold cavity is controlled during the explosion by releasing combustion gases from the mold cavity.

Process and apparatus for the production of plastic objects

A process and apparatus are provided for cleaning contaminated earth. The contaminated soil is first frozen using freezer boxes which are placed on the surface of the ground to be frozen. A refrigerant, preferably liquid nitrogen, is then introduced into the box until the soil is frozen to a desired depth and temperature. The frozen soil containing pollutants is then removed and placed in sealed containers for optional further treatment.

Process and apparatus for cleaning contaminated soil

For the fluorination of synthetic resin articles, e.g., containers, the article to be fluorinated is positioned in a gastight chamber, and a fluorinating treatment gas is produced from a fluorine precursor in situ, e.g., with the aid of a plasma torch from a basic gas mixture comprising a fluorine-containing compound, e.g., CF.sub.4 or SiF.sub.6.

Process for the fluorination of synthetic resin articles

An apparatus for the deburring or coating removal of workpieces which are subjected to direct heat exchange with a low temperature coolant, e.g. liquid nitrogen, has a transport path extending around a sling wheel to which a granular path medium is supplied via a hollow shaft which is cantilever journaled externally of the treatment chamber. The blast medium is fed to the sling wheel via a nonrotatable tube extending through the hollow shaft so that centrifugal force does not cause free flow media to adhere to the inner walls of the shaft and impede delivery to the sling wheel.

Article-treating apparatus

Tunnels are constructed by freezing soil and removing frozen soil between starting and end shafts of the tunnels. Tunnels are driven in an uncomplicated manner in rapidly changing soils without auxiliary construction means. A hole is bored in or near the planned axis of the intended tunnel between starting and end shafts. A soil freezing work pipe is inserted into the hole. The pipe is cooled by a cooling agent. The soil freezing work pipe continues to be cooled until an ice and frozen soil mass has formed around the work pipe, which frozen mass has a diameter which is larger than that of the planned tunnel. Frozen soil is subsequently excavated, leaving a frozen soil lining, which is immediately supported by a primary support lining or a permanent lining.

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Geretsried-Gelting, Germany

Dieter Rebhan