Abstract: The process for preparing a polyamide based on dicarboxylic acids and diamines has the following stages: 1) providing an aqueous monomer mixture of dicarboxylic acids and diamines, the molar ratio of dicarboxylic acids to diamines being adjusted such that a molar deficiency of dicarboxylic acids or diamines of from 1 to 10 mol % is present at the outlet of stage 3), based on the other component in each case, 2) transferring the aqueous mixture from stage 1) to a continuous evaporator reactor in which diamines and dicarboxylic acids are reacted at a temperature in the range from 100 to 370° C. and a pressure in the range from 1 to 50 bar, 3) transferring the mixture from stage 2) to a separator which is operated at a temperature in the range from 100 to 370° C.

Abstract: The process for preparing a polyamide based on dicarboxylic acids and diamines has the following stages: 1) providing an aqueous monomer mixture of dicarboxylic acids and diamines, the molar ratio of dicarboxylic acids to diamines being adjusted such that a molar deficiency of dicarboxylic acids or diamines of from 1 to 10 mol % is present at the outlet of stage 3), based on the other component in each case, 2) transferring the aqueous mixture from stage 1) to a continuous evaporator reactor in which diamines and dicarboxylic acids are reacted at a temperature in the range from 100 to 370° C. and a pressure in the range from 1 to 50 bar, 3) transferring the mixture from stage 2) to a separator which is operated at a temperature in the range from 100 to 370° C.

Abstract: A process is provided for the preparation of polyamides in an aqueous reaction mixture containing a nitrile selected from 6-aminocapronitrile and adipodinitrile, wherein a nitrile is used through which, in the liquid state, a gas inert to the nitrile has been passed.

Abstract: Disclosed is a spray concrete which, even at a water-cement ratio of 0.45 to 0.55, is still easy to work, can be sprayed well, and sets and hardens rapidly. It contains, in addition to the conventional additives, additions of naphthalinesulfonicacid-formaldehyde condensation products and highly concentrated alkaline aqueous solutions of potassium aluminate, potassium carbonate and caustic potash. The concrete according to the invention displays an especially rapid solidification when it contains up to 3% by weight alkali silicates or an adequate amount in highly dispersed silicic acid (SiO.sub.2). The additives are incorporated into the concrete preferably directly at the worksite prior to spraying.

Abstract: An apparatus for applying adhesive or adhesive pastes in strips on construction or building surfaces comprising a heated hopper container for adhesive mounted on a traveling positive displacement pump, a manifold at the pump outlet provided with a plurality of moveable outlet openings and connected to separate conveying tubes and application nozzles, the positive displacement pump having a widened intake cross-section or a feed screw with a widened in-take cross-section and the hopper having a cylindrical upper section and a lower section conical in only one plane with a heatable screen grid in the transition point between the upper and lower hopper sections, the feed screw and the pump being at least partially heated, the drive shaft of the pump being provided with a safety crank and thermostatically controlled heating element and the hopper being provided with a closable by-pass carrying 2 or more individually or jointly, adjustable horizontally and vertically and elastically rotable slot nozzles mounted sl

Abstract: The present invention relates to liquid mixtures of alkali metal silicates, water, and trialkoxysilanes of the general formula R--Si(OR').sub.3, which harden to form silica-containing gels within a predetermined length of time. The mixtures can contain additional means for influencing the gelling and the gel strength. The most important field of application of the gels in accordance with the invention is the stabilization of soils in architecture and civil engineering.

Abstract: The present invention relates to liquid accelerators for the setting of concrete mixtures. These accelerators have a long shelf life even in higher concentrations than the liquid accelerators known heretofore and, within the defined concentrations, produce no precipitation. The new accelerators are characterized by containing only potassium aluminate, potassium carbonate and potassium hydroxide in a defined range. They can be used in any known hydraulic binding agents, they shorten the set time of these binding agents, and they improve the compressive strength of the products made with them.

Abstract: A service elevator, designed to carry persons up or down along a building wall or other structure, comprises a ladder secured to that structure and a carriage on which an endless conveyor band is supported. The band has projecting dogs engaging the rungs of the ladder which are held between a first stringer of circular cross-section and a second stringer of rectangular cross-section. The band-supporting frame has sleeves slidably engaging the first stringer and roller pairs bracketing the second stringer. A second conveyor band, serving as a standby for the working band, corotates therewith and has dogs slightly offset from those of the latter for dropping onto the rungs when the working band fails.

Abstract: Dispensing cap for valves for aerosol containers, comprising a stationary body designed to be secured to the container and a dispensing push button which is designed to be connected to the actuating stem of the valve, wherein the body has a deformable portion which is hingedly or pivotally mounted on the remainder of the body at its two ends and which can be displaced inwards into the body for actuating the push button, and a frangible device which acts as a tamper-proofing device and which initially is connected first to the deformable portion of the body at at least two points lying on opposite sides of a hinge or pivotal connection of the deformable portion, and wherein the device, until the purchaser tears it off, prevents the deformable portion from being pressed inwards into the body.