SLOW-IN DEVICE FOR DRY CONCRETE MIXTURE AND SIMILAR BUILDING MATERIALS IN A PNEUMATIC SPRAYING PIPE LINE AND SPRAYING MACHINE WITH SUCH A LOW-IN DEVICE

摘要

The device for transferring granular dry material into a pneumatic feedpipe (32), for example a concrete spraying machine, consists of a material-feeding hopper (4) having a blocking slide valve (6) which can be actuated by a pneumatic working cylinder (8). Arranged one behind the other underneath the blocking valve (6) are two tube sections (16 and 22) which are each subjected to the action of a tube-squeezing device (34 and 38 respectively), between which the tube sections (16 and 22) form a sluice chamber (44) which is additionally provided with a blowing-air connection (62). The blocking valve (6) and the upper tube-squeezing device (34) form a prechamber (42). When the upper tube-squeezing device (34) is closed and the blocking valve (6) is open, the prechamber (42) is filled by free fall from the feeding hopper (4). The sluice chamber (44) can at the same time be discharged into the pneumatic pipe (32) by opening the tube-squeezing device (38). The top (6) and bottom (38) blocking elements then close again and the contents of the prechamber (42) are discharged into the sluice chamber (44) by opening the upper tube-squeezing device (34). The tube-squeezing devices (34 and 38) work against an empty tube. The only blocking elements in contact with the material is the blocking valve (6). Otherwise, the device has no sealing parts which are subject to wear. IMAGE