Abstract: The water necessary for the production of concrete is replaced by a super-cooled, cooling transfer agent, comprising snow crystals. The cooling transfer agent is produced by mixing water with air and a cooling medium, such as liquid nitrogen, to give a cold gas mixture. The cold gas mixture is sprayed in the form of a cold gas stream. The snow crystals thus formed from the water are brought to a low temperature, of, for example, below minus 30° C. and added to the mixture of binding agents.

Abstract: The invention relates to a gas distribution system which can be connected to a gas supply, the purpose of said gas distribution system being to admit and distribute a non-oxidizing gas in a shroud (17, 20, 21, 23) covering at least one solder container (22). Printed circuit modules (12) are transported through said shroud and while they are being transported, are brought into contact with a wave of solder (24). The gas distribution system has at least one gas distributor situated above and at least one gas distributor (19, 31) situated below the printed circuit modules (12) in order to produce a protective gas atmosphere with low residual oxygen values. Both gas distributors are provided with flow elements (48, 49, 51 to 56, 59; 35, 37, 44, 45). Said flow elements produce a displacement gas blanket which is distributed homogeneously over the discharge surfaces (59, 44, 45) directed towards the solder container.

Abstract: A soldering apparatus has a solder container and a casing to accommodate a protective-gas atmosphere for soldering printed circuit boards. During transport of the circuit boards through a casing the circuit boards are brought into contact with a solder wave in the container. The casing has an inlet for printed circuit board on an inlet side and an outlet on its outlet side. In addition, the casing has a supply of non-oxidizing gas and an arrangement for admitting gas into the casing. The casing is designed as a modular construction kit having subassemblies and/or constructional elements which comprise an input tunnel, an entry tunnel, at least two covering elements, an outlet tunnel and a detachable connection on the solder container and/or the sub-assemblies and/or constructional elements to connect the sub-assemblies and/or constructional elements and the solder container.

Abstract: The invention relates to a method for mechanically removing solder beads (14) from the surface of printed circuit boards (10) directly after they pass through the solder flow during flow soldering of printed circuit boards in a soldering plant. In order to ensure that the solder beads are mechanically removed without damaging the printed circuit boards, the solder beads (14) are mechanically removed by means of at least one jet (50) of cold gas directed onto the surface.