GB390257A - Improvements in or relating to the conveyance and mixing of granular materials such as concrete or the like - Google Patents

Abstract

390,257. Mixing. BONGARDT, E., 40, Obere-Zahlbacherstrasse, Mainz, Germany. Dec. 10, 1931, No. 34270. [Class 86.] In a compressed-air conveyer system for conveying and mixing materials composed of constituents of different grain sizes and different specific weights, such as, for example, concrete, the air pressure does not exceed a maximum of 1 atmosphere, and the volume of air is at least a hundredfold that of the material conveyed. The constituents are supplied continuously and at a uniform speed to a preliminary mixer 5, Fig. 1, where they are mixed with a little water. The material falls from the mixer on to a feed screw 4 which compresses it into a plug within the conical part 9 of the casing. A scraper 10 at the end of the feed-screw shaft removes material from the face of the plug, and the scrapings falling in front of the nozzle 11 of the blower 1 are blown through the conduit 2 to a rotary final mixer. The water required for the final mixing is admitted through the pipe 7. In a modification, the conical end of the casing is replaced by a conical hopper 17, Fig. 2 made in two sections, the upper of which is movable and is urged downwards by a weight or springs acting through a lever 19 on a pin 20. Each part of the hopper may be movable. If the conduit 27 and connection 28 become blocked, a disc 23 on the shaft of the feed screw 16 is forced to the right, and through the pins 24 and linkage 25, 26 actuates stop mechanism for the screw and a signalling device. The lower part of the disc is pivoted to the upper in order that it may turn, as shown in dotted lines, if there is material behind it. The stop &c. mechanism also may be actuated through the lever 19 when the upper part of the hopper recahes its highest position. The air conduit 27 is connected by a branched pipe 31 to opposite sides of the connection 28. The flow of air is regulated by adjusting the valve 32 and register 30. In a further modification, a hopper 33, Fig. 5, contains a vertical shaft 34 provided with vanes 35 and a worm 36. A grooved or ribbed cone 39 is slidably but non- rotatably mounted on the lower end of the shaft, and normally is forced against the lower edge 41 of the hopper by an adjustable spring 40.