Patent GB-878249-A (GB)
Title: Apparatus for making and delivering hardening mixtures of a binding agent, more particularly cement, and water
IPC: B28C5/12
Filed: 1959-03-12
Abstract: 878,249. Batch-mixing machines. KALICH, R. March 12, 1959 [March 19, 1958],. No. 8547/59. Class 86 [Also in Groups XVIII and XXX] Apparatus for making and delivering a mixture of cement and water (or like hardening mixture of a binding agent) comprises a screw conveyer, a weighing machine and a mixing container combined in a single unit in which the weighing machine may receive cement from the conveyer and deliver a measured quantity to the mixing container where it is mixed with water and discharged. The connection between the conveyer 13 and the weighing machine comprises an outlet member 32 projecting through a slot 31 (Fig. 2) in the roof 30 of the weighing receptacle 11, both the roof 30 and a cover 35 attached to the outlet 32 being in the form of surfaces of revolution about a common horizontal axis about which the conveyer is pivoted. As shown the roof and cover are spherically curved about a centre lying on the common axis of bearings 28, 29 (Fig. 4) which support a bracket 27 attached to the outlet end of the conveyer.  Automatic feed weighers. The weighing receptacle 11 from which the mixer 4 is fed is mounted on a weigher 12 which includes an indicator 66 which closes electric contacts at 20 when the receptacle is empty and at 21 when it contains a predetermined load. These contacts are respectively employed to start and stop a motor (not shown) which drives the conveyer screw. Discharge from the receptacle is through an outlet closeable by a gate 39 pivoted at 40 and operated by a pneumatic cylinder 19. This gate is automatically opened by means controlled by the mixer as described below and is automatically reclosed after discharge of a load by means responsive to the closure of contact 20. Mixers. The mixing container 4 has an aperture 41 in the top 42 normally sealed by a member 45 but openable by rotation of an arm 44 about its pivot 47 through the agency of a pneumatic cylinder 13. The inlet to the container 4 is in the form of a funnel 38 which surrounds the discharge end of the weighing receptacle. Within the container 4 is a stirring mechanism 9 continuously rotated by the motor 10 and communicating with the container are pipes 48, 49, 50 leading respectively to an automatic water meter 17, a valve 15 of the compressed air container 8, and a pressure gauge 16. The base of the container (which may be detachable) has a helical surface 60, Fig. 6 (not shown) which progresses downwards in the direction of rotation of the vanes 56 of the stirring mechanism and communicates with the outlet pipe 5 in which is a ball valve 6. The ball of this valve closes a constriction in the bore of the tube 5 under the action of its own weight. Operation. With the apparatus fully charged, in which state the weighing receptacle 11 contains a measured weight of cement and the mixing container 4 a mixture of cement and water, a demand for delivery of the mixture is made by the closing of a switch operable either manually or automatically by a concrete mixer to be fed by the apparatus. This switch operates a valve 15 to admit compressed air to the container 4. The resulting pressure forces the mixture into outlet pipe 5, the ball valve 6 being slid up a guide into a by-pass to allow discharge of the mixture, the size of the constriction in the bore and the weight of the ball being such that the ball will remain in the by-pass until the air pressure falls suddenly when the mixture has been fully discharged. The fall in pressure is sensed bv the gauge 16 which then actuates both the water meter 17 to introduce a measured quantity of water and also valve 14 to allow cylinders 18 and 19 to open the cover members 45 and 39 in turn to feed in the cement. When the weighing receptacle is empty the covers 45 and 39 reclose automaticaly by the electrically controlled reversal of valve 14 effected by switch contact 20 of the weigher, which contact also initiates the refilling of the weighing receptacle.