Abstract: A process and an apparatus for melting solidified gel masses, in particular of photographic emulsions, which are introduced as solid pieces of any size or shape into a melting container having a perforated bottom and equipped with a tempering device, the gel mass when melted flowing through the openings in the bottom into a receiver underneath it, and being arranged and designed to prevent excessive exposure of the gel mass to heat. This is achieved by melting the layer of gel mass immediately above the bottom of the melting container with microwaves while the layers of gel mass situated above the aforesaid layer remain substantially uninfluenced by the radiation of microwaves.

Abstract: A flotation process for the continuous recovery of silver or silver compounds from solutions or dispersions is described, wherein finely divided, inert gas bubbles are injected into the dispersions of silver and silver compounds in the presence of protein and the pH of the medium is maintained at the isoelectric point of the protein. Addition of a surface active agent accelerates the process. The desilverized effluent has a silver content of less than 1 mg of Ag/l. The quantity of flotate (12) is less than 2% of the quantity of effluent (5) put into the process.

Abstract: A process for the multiple coating of webs which are continuously moving past a coating point, using coating apparatus according to the bead coating process is carried out such that any number of comparatively high viscosity layers is arranged above an accelerating layer which lies below the layers and has a viscosity range of from 1 to 20 mPas and a layer thickness of from 2 to 30 .mu.m. A very small gap width of from 100 to 400 .mu.m is selected between the sliding surface coating head and the web to be coated and only a low reduced pressure is applied under the coating head. By this process, coating rates of 400 m/min and more may be achieved with a good coating quality.

Abstract: A process for the multiple coating of objects or webs which are continuously moving past a coating point, using coating apparatus according to the curtain coating process. This process is carried out such that any number of comparatively high viscosity layers is embedded between an accelerating layer which is positioned below the layers and has a viscosity range of from 1 to 20 mPas and a layer thickness of from 2 to 30 .mu.m, and a spreading layer which is positioned above the comparatively high viscosity layers and has a viscosity range of from 1 to 10 mPas and a layer thickness of from 5 to 20 .mu.m. By the curtain coating process, coating rates of 400 m/min and more may be achieved with a good coating quality.

Abstract: In a process for the pretreatment of photographic substrates in order to improve adhesion during subsequent coating with photographic emulsions, the corona discharge is carried out under a reduced pressure in order to treat the substrate, resulting in an improvement in the adhesion and wettability which lasts over a long period as well as a reduction in the residual charges generated or left on the substrate by the corona discharge.

Abstract: The invention relates to a web guide roller for a web which is required to be moved at a high speed, having cavities arranged on its surface for receiving the air carried with the moving web, whereby a finely branched network of compression chambers is arranged on the surface between plateau-like smoothly ground and polished areas on which the web lies in contact. Further the invention relates to a process for the production of this web guide rollers for use at high speed.

Abstract: The invention relates to an apparatus and process for simultaneously coating several layers to moving objects, particularly webs, whereby at least two liquid coating materials issue over the width of V-shaped sliding surfaces or above following sliding surfaces are delivered to the two sliding surfaces which are arranged in the form of a V and which form a discharge edge above the objects or web to be coated, flow down the underside of the V-shaped sliding surfaces, combine at the end of the sliding surfaces to form a multiple layer film of liquid which is deposited in the form of a free falling curtain onto the objects or the web of layer support material.

Abstract: Process for the production of photographic emulsions consisting of water-immiscible or water-insoluble organic substances and an aqueous solution of an organic binder, characterized in that the hydrophilic and hydrophobic phases are heated separately, each to its particular temperature above its liquefaction point, and then continuously dosed into a dispersing chamber.

Abstract: The invention relates to a process for the production of photographic emulsates consisting of dispersions of water-immiscible or water-insoluble particles in aqueous binder solution, characterized in that the entire non-aqueous phase is initially introduced at a temperature above the liquefaction temperatures of the aqueous and non-aqueous phases, after which a relatively small volume of aqueous phase is emulsified continuously or in portions into the non-aqueous phase by known methods and then more aqueous phase is introduced while emulsification is continued in such a quantity that the viscosity of the emulsion passes through a maximum (indicating phase reversal into an emulsion of non-aqueous particles in aqueous dispersion medium (FIG. 1)).

Abstract: The invention relates to a process and an apparatus for continuously filtering liquids whereby two candle filters are arranged closely adjacent to one another and are connected by a first three-way cock at the liquid inlet ends, a second three-way cock at the liquid outlet ends of the candle filters and a bypass cock for a partial stream and enabling the candle filters to be emptied in such a manner that the candle filters are filled and vented before they are put into operation and one of the two candle filters always is ready for operation with degassed and filtered liquid if one of the candle filters is to be cleaned.

Abstract: The electrical conductivity of the surface of eloxated aluminium rollers in the pores of the eloxation layer a metal is deposited which has little or no tendency to corrosion.

Abstract: An arrangement for the production of webs coated with several emulsions, comprising coating and drying means arranged in succession, in the latter being connected to air supply and discharge shafts. A plurality of coating means are arranged at a selectable spacing from one another along the web which is guided in loop formation, the physical parameters for coating and drying are adjustable for each layer.