Abstract: The invention relates to a heat generator for well stimulation, comprising a tubular fuel vessel (22) with two or more mutually separated, closed segments (23) arranged in longitudinal succession and each at least partly filled with fuel (30), and at least one igniter (40) for ignition of the fuel in at least one of the segments (23), wherein the ends of the segments are connected such that the fuel in a subsequent segment is ignitable owing to the evolution of heat in the course of burnoff of the fuel in a preceding segment. The invention further relates to a process for well stimulation using an inventive heat generator.

Abstract: The invention relates to a process for the aluminothermic welding of rails, the aluminothermically produced steel being poured into a refractory mold surrounding the rail ends which are to be joined, and alloying additives being contacted with that part of the steel which runs out of the reaction crucible and forms the weld in the rail head region, wherein the alloying with the alloying additives is carried out after the completion of the aluminothermic reaction and separation of the steel from the slag via the diverting plug in the mold, and the overflow in the is closed.

Abstract: The invention relates to a process for the aluminothermic welding of rails, the aluminothermically produced steel being poured into a refractory mold surrounding the rail ends which are to be joined, and alloying additives being contacted with that part of the steel which runs out of the reaction crucible and forms the weld in the rail head region, wherein the alloying with the alloying additives is carried out after the completion of the aluminothermic reaction and separation of the steel from the slag during tapping and before the steel runs into the casting cavity formed by the mold, and the overflow in the casting mold is closed.

Abstract: The invention relates to an automatically opening tapping thimble made from a refractory material for casting crucibles which are used in aluminothermic reactions. This thimble consists entirely or partially of air-permeable graphite or metal whose melting point lies between 2100 and 3727.degree. C.

Abstract: The invention relates to an aluminothermic mixture consisting of a finely particulate base portion of iron oxides and aluminum as well as metallic additives, wherein a master alloy, namely a ferrochromium alloy consisting of (in % by weight)C: 0.1 to 20Si: 2 to 40Cr: 5 to 80and iron with impurities resulting from manufacture and, if appropriate, other alloying elements, is added in a quantity of from 5 to 50% by weight, relative to the base portion, as metallic additive.

Abstract: In order to reduce the residual stresses which occur in the region of a fusion weld of two rail ends (1,2), in order to reduce, in particular to make uniform, the cooling-down rate and--associated with this--the crystallization process within the solidifying weld material, a casting mold is proposed which is equipped with a system of risers (9) and air vents (10) which are designed symmetrically with respect to a longitudinal center plane (5) and a transverse center plane (3) of the welded joint, the risers (9) and the air vents (10) being physically distributed as a function of geometric parameters of the rail foot (8) and of the weld bead (4), and the cross sections of the air vents (10) being dimensioned as a function of the cross sections of the risers (9).

Abstract: Disclosed is a method for the aluminothermal production of molten steel for the aluminothermal welding of workpieces, wherein the aluminothermal reaction is carried out in a crucible made of porous or hollow spherical .alpha.-Al.sub.2 O.sub.3 with a density of 0.8-3.0 g/cm.sup.3 and a bulk density of 0.3-1.8 g/cm.sup.3.

Abstract: The invention relates to a plain bearing alloy on a tin basis with antimony and copper, the alloy consisting of 6 to 15% by weight of antimony, 3 to 10% by weight of copper, 0.05 to 1% by weight of silver and 0.1 to 2% by weight of zinc, the remainder being tin.

Abstract: Method for intermediate cast type welding of finely pearlitized rails by pouring steels produced by the Thermit fusion process into a casting mold, which surrounds the two rail ends 13 separated from each other by an intrinsic gap L1, wherein the actual rail gap L1 is increased across the entire rail head width 14 starting on both sides of the rolling surfaces 8 of each rail end 13 in longitudinal -h and vertical -v direction by a dimension of 1/10 to 10/10 of the dimension of the intrinsic rail gap L1 to a dimension of L2.

Abstract: Method for raising rail joint welds lying below the traveling surface on railroad tracks by heating the weld by means of an aluminothermic mixture which solidifies after reacting, wherein a) the aluminothermic mixture (21) is used in an amount measured in kilograms equalling from one fifth to one tenth of the weight per meter of the rail (15) measured in kilograms, wherein a1) 30 to 60% of this amount is used to heat the base (10) of the rail in a length of 150 to 300 mm (as measured symmetrically with reference to the weld in the longitudinal direction) and a2) the rest of the aluminothermic mixture (21) is used in equal proportions to heat both sides of the rail web (18), b) the aluminothermic mixture (21) is ignited, c) remains on the rail (15) after igniting for a period measured in minutes which corresponds to 0.7 to 1.5 times the number of kilograms of the aluminothermic mixture (21), whereupon d) the reacted and compacted mixture is removed from the base (10) and from the web (18) of the rail.

Abstract: A metallothermal reaction mixture consisting of a metal oxide, a metal that is more electronegative than the metal of the metal oxide and, optionally, further additives, the individual components being present in the form of small particles, is prepared in which at least 20% by weight of the metal oxide is present in the form of spherical or at least approximately spherical particles ranging in size from >0 to 3.0 mm. A stabilization and evening out of the reaction is achieved by the invention composition of the reaction mixture.

Abstract: Aluminothermically produced steel is poured into a casting mold which surrounds the two rail ends. A cooling agent is applied to the surfaces of the rail heads of the rail portions adjacent the two casting mold halves. The cooling agent is applied after the molten steel has been poured into the casting mold until the steel has solidified. The cooling agent may be applied until the projecting material and the casting mold halves has been sheared off. A casting mold for carrying out the method includes two casting mold halves which each has a groove for receiving a sealing paste in the inner surfaces thereof facing the rail ends, wherein the groove extends along the outer contour of the casting mold halves.

Abstract: A method for grinding the running and/or guide surfaces of rails or the like, where the running surfaces are ground by an endless revolving abrasive belt which can be moved against the running surfaces, wherein the abrasive belt revolves transversely to the longitudinal axis of the rail and embraces, at least partially with prestress, the running and/or guide surfaces. An apparatus for performing the method includes a mobile grinding machine, which an endless abrasive belt, guided at least on one rail of the track, which abrasive belt revolves over a drive roller and a reversal arranged at a distance therefrom and which can be moved by these against the surfaces of the rail to be ground. The reversal is formed of two reversing rollers which have a comparatively small spacing from each other, that the axes of the reversing rollers and of the drive roller 19 being arranged to be parallel to the longitudinal axis of the rail.

Abstract: Aluminothermic heating blocks for use in heating metal objects, such as rails, and methods for their manufacture are disclosed. The blocks are made by setting a mass of particulate aluminum, iron oxide, heat absorbing material, alkali metal silicate binder and water.

Abstract: A grooved rail switch with a tongue rail device includes a tongue rail displaceably supported on a torsion-stiff support box for movement between a stock rail and a switch rail. The support box is made up of an upper slide plate, a lower bottom plate and flat bars extending between and welded to the slide plate and bottom plate. High strength bolts secure the stock rail to one side of the support box and the switch rail to the other side.

Abstract: This invention relates to an improvement in a frog for switches, in particular for rapid transit switches, with a junction rail mounted in a rotatable manner and adapted to close a gap between pairs of rails of straight or branch track, the improvement comprising that the two ends of the junction rail have the shape of an isosceles triangle and the corresponding ends of a transit rail taper on one side, whereby a continuous rail-head profile is formed when the junction rail abuts the transit rail.

Abstract: A self-opening closure for casting crucibles used in aluminothermic reactions and made of a high mechanical-strength, high boiling point inorganic material producing no gases when heated, the closure being composed of one or more sealing disk(s) made of a fibrous aluminum silicate, the ratio of the total thickness of the sealing disk(s) to its (their) diameter being 1:5 to 1:1, the melting point of the aluminum silicate being equal to or exceeding 1650.degree. C., and a metal plate between 0.1 and 3 mm thick mounted on the sealing disk(s).

Abstract: The invention concerns a corrugation-free rail for track-bound vehicles. In the invention, the rail comprises a metallic material in the area of the travel and/or guide surfaces of which the stress limit or yield point is above the wheel-induced compression. Preferably, the rail in the area of the travel and/or guide surfaces is composed of a non-work-hardenable material.The preferred material composition is (by weight):______________________________________ carbon 0.2 to 0.4% chromium 13 to 18% molybdenum 0.3 to 1.5% manganese 0.5 to 1.5% silicon 0.3 to 1% remainder is iron.

Abstract: This invention relates to a prefabricated casting mold for aluminothermically welding rail ends spaced apart by a gap while simultaneously welding shut a fishplate hole in the region of each rail end, comprising two mold halves which, when assembled, form a cavity adapted to enclose the rail ends and being so widened in the region of the rail web and in the longitudinal direction of the rails that the two fishplate holes are located within the cavity, a pair of riser channels in each mold half, at least one of the riser channels in each half issuing centrally into the rail base region of the casting mold cavity and having at least one means of communication with the casting mold cavity in the rail web region, and the other of the riser channels in each mold half communicating with the casting mold cavity in the vicinity of a fishplate hole.

Abstract: This invention relates to an improvement in a point switch in which the switch blades or tongues are composed of rail sections of the trunk or main track and are displaceably positioned on slide chairs in the transverse rail direction, the improvement comprising a shaft on which each slide chair is slidingly mounted between two bearing blocks, one of the bearing blocks being inside the track and the other of the bearing blocks being outside of the track, welds rigidly connecting the bearing blocks with a joint base plate, and two rods on each chair parallel to the shaft, a first one of the rods being adapted to contact a stop in a recess in the outside bearing block, and a second one of the rods being adapted to contact a lock in a recess in the outside bearing block, whereby in an unlocked condition the first one of the rods contacts the stop, and in a locked condition the second one of the rods contacts the lock.