JPS6130817B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for carrying out gravity mixing of bulk materials in one container by taking partial quantities from different bulk material levels and subsequently aggregating these partial quantities. The present invention relates to a gravity mixing device having a silo vessel with a conical bottom and built-in devices for the removal and subsequent aggregation of partial quantities of bulk material from different levels.

A gravity mixing device having these characteristics is known from German Patent Specification No. 1757540. The built-in device for withdrawing partial quantities of bulk material from different levels consists of a number of uprights provided with numerous transverse holes, the lower part of which traverses the conical bottom of the silo vessel and is connected to a common withdrawal pipe. Consists of a tube. This solution is structurally complex, contains significant static difficulties due to the unidirectional loads acting on the pipes and their connecting pipes, and, finally, is also unsatisfactory in terms of mixing results. This is due to the fact that the transverse holes allow the bulk material to enter the tube only from one side and are poorly controlled in quantity. Moreover, the bulk material entering through the upper holes and flowing downward in the respective tubes may block and even completely overwhelm the lateral bulk material flow through the respective lower holes. be. This results in the filling volume of a partial region not participating in the mixing process.

The problem underlying the invention is to create a gravity mixing device for carrying out a process of the aforementioned type in which the entire contents of the silo vessel take part in the mixing process, provided that this silo vessel is inter alia The parts are configured in such a way that the static and dynamic stresses occurring during operation remain monitorable and structurally controllable.

The task is to remove partial quantities from different bulk material levels and subsequently mix them by aggregating them from a plurality of annular parts symmetrical about the central axis of the container, and A conical base and portions from various levels for carrying out the method of assembling each partial quantity withdrawn with the partial quantity withdrawn from the next level at the height of this level. In an apparatus having a silo vessel with a built-in device for removing and subsequently collecting a quantity of bulk material, the build-in device consists of mutually similar hoppers arranged one above the other along the central axis of the silo vessel; The inlet cross-section lies approximately at the outlet cross-section of the hopper directly above, and the hopper opening angle is just less than that angle that ensures mass flow into the bulk material in question, and the hopper is aligned with the central axis of the silo vessel. The problem is solved by a device which is arranged in parallel tension supports and spacers are arranged between the hoppers.

Advantageous embodiments of developments of this gravitational mixing device are provided in claims 2 to 4.

The solution according to the invention is based on the fact that each partial quantity taken from a given level is mixed directly with the total quantity of the partial quantities of the level above it.

An important requirement for the device solution is to adjust the hopper opening angle so that in each hopper a so-called mass flow (as distinct from a so-called particle flow) and therefore an approximately uniform descent of the bulk material over the entire hopper cross-section is obtained. The idea is to allocate it in such a way as to guarantee it. In order to determine the maximum hopper opening angle, the strength parameters (internal friction angle, wall friction angle, cohesive force) of the bulk material or multiple bulk materials to be mixed are measured using a shear test device by Ienike (Schergerat nach).
Jenike). From the measured values, the maximum hopper opening angle which ensures further mass flow can be derived using the commonly known standard Jenike method.

The invention will be explained in detail below with reference to drawing examples.

According to FIG. 1, a silo container 1 has a large number of identical hoppers 2 arranged vertically on the central axis of the silo container.
are provided, each hopper consisting of a cylindrical tube section followed by a conical section. Each of these hoppers connects to the level of the upper edge of the hopper directly below it. Each hopper thus discharges its contents into the hopper immediately below it, with a simultaneous flow of other bulk material from the side. The key is to maintain mass flow conditions within each hopper.

In the embodiment according to FIG. 2, the lowermost hopper 5 is located outside the silo container, ie follows its conical bottom outlet.

FIG. 3 shows an advantageous method of fixing the hopper in a silo container. For this purpose, the hopper 2 is arranged on the support member 3, more specifically, by using a tubular member welded to the outer wall of the hopper 2 parallel to its central axis. Spacer sleeves 4 are used to maintain the required distance between each hopper. The fixing of the tension members in the silo container is carried out in any suitable manner known to the person skilled in the art, taking into account the static conditions.

In the case of the gravity mixing device described above, the bulk material removed from the outlet of the previously filled silo vessel 1 is in most cases sufficiently homogenized. Only if the silo container is filled with charges whose properties are highly variable and/or if particularly high requirements are met for the homogeneity, composition and properties of the removed coarse material, the mixing result after one pass may be Furthermore, it does not meet the required quality. In this case, a gravity mixing device according to FIG. 4 can advantageously be used. The device contains a suction pipe 6 extending from the outlet of the container over the top hopper 2, which suction pipe is fixed to a roof truss 6a and whose upper opening faces a conical drift section 12. The outlet of the silo container 1 is surrounded by a head 7 which has an air inlet 8 which is connected to a blower 9 via a conduit. Furthermore, this head 7
has a conical bottom with an outlet 10, which can be closed by a suitable device, for example a rotary vane feeder 11. In this embodiment, the gravity mixing device can also be operated as a rotary mixer if desired. For this reason, a partial volume flow that has already been mixed a number of times flows into the silo container 1.
From the outlet of the compressed air is returned upwards in a suction pipe 6 in a manner known per se, and the closure device 11 remains sealed. The conveying air can escape through an outlet 13 provided in the silo roof.

Furthermore, the hopper 2 is simultaneously secured to the suction pipe 6 via a corresponding truss 2a, so that separate tension supports are eliminated.

[Brief explanation of the drawing]

1 and 2 are longitudinal sectional views each schematically showing an embodiment of the device according to the invention, and FIG.
2 and 2, and FIG. 4 is a schematic longitudinal sectional view of a further embodiment of the device according to the invention. 1... Silo container, 2... Hotsupa, 3... Zhang support material,
4... Spacer, 5... Bottom hopper, 6... Suction pipe,
7...Head, 8...Compressed air inlet, 10...Bulk material outlet.

Claims (1)

Claims: 1. Partial quantities from different levels of bulk material are removed from a plurality of annular parts symmetrical about the central axis of the container for mixing by subsequent aggregation of these partial quantities. a conical bottom and various In an apparatus having a silo vessel with a built-in device for removing and subsequently aggregating partial quantities of bulk material from the level of become, each hoppa 2
, the inlet cross-section of the hopper lies approximately at the outlet cross-section of the hopper immediately above, and the hopper opening angle is just less than that angle that ensures mass flow in the bulk material concerned, and the hopper 2 is located at the center of the silo vessel. Apparatus for gravity mixing bulk materials in a container, characterized in that they are arranged on tension supports 3 parallel to the axis and spacers 4 are arranged between the hoppers 2. 2. Bulk material according to claim 1, characterized in that the conical bottom of the silo container terminates in the inlet cross-section of the lowermost hopper, the outlet cross-section of which forms the silo outlet. A device for gravity mixing in a container. 3 The hopper 2 surrounds at a distance a suction pipe 6 arranged concentrically thereto, and the outlet of the silo 1 has a head 7 with a compressed air inlet 8 and a closable bulk material outlet 10. Claim 1 or 2, characterized in that it ends in
Apparatus for gravity mixing the bulk materials according to any of the preceding paragraphs in a container. 4. Apparatus for gravity mixing bulk materials in a container according to claim 3, characterized in that the hopper 2 is fixed to the suction pipe 6.