GB2045101A - Supplying materials to a mixing chamber of a mechanical mixer - Google Patents

Abstract

A mechanical mixer has a mixing chamber (11) mounted for rocking or rotational movement about a horizontal axis (X), at least two openings (24) in the chamber wall on the same side of the horizontal and means (26) for releasably attaching a drum (10) containing one constituent of the mixture to the chamber at each of said openings so that the interior of each drum communicates with the interior of the mixing chamber via one of said openings. In the embodiment shown, the chamber (11) is also rotatable about a vertical axis (Y); in other embodiments this is not so, but in one of them a rotary stirrer is provided instead. <IMAGE>

Description

SPECIFICATION Mechanical mixers This invention relates to mechanical mixers in which the constituents which form the mixture are tumbled in a mixing chamber.

As will be known mechanical mixers of this kind comprise a rotatable, or otherwise movably mounted, mixing chamber with one or more openings through which the constituents are introduced, the openings being sealed before mixing commences. The introduction of the constituents through the openings necessarily involves decanting supply containers, usually drums, in which the constituents are supplied or stored in buik and there is a risk of losing material by spillage, evaporation or aspiration into the atmosphere. This loss is undesirable in any event but if the materials are noxious, a health hazard may result.

According to the invention in one aspect a mechanical mixer comprises a mixing chamber mounted for rocking or rotational movement about a horizontal axis, at least two openings in the chamber wall on the same side of the horizontal and means for releasably attaching a constituent supply container at each of said openings so that the interior of each container communicates with the interior of the mixing chamber via one of said openings.

It will be appreciated that with the provision of a mechanical mixer as aforesaid containers of the respective constituents can be brought to the mixer in a closed condition and opened prior to their being clamped to openings in the mixing chamber in a leak tight manner. Mixing is then commenced by rocking or rotating the mixing chamber with the containers attached. When mixing has been completed the mixer is brought to rest in an attitude such that the containers are upright. The containers are supported from below, unclamped from the mixing chamber and each containing a portion of the mixture are fitted with temporary closures. Mixing may be assisted by rotary paddles within the chamber. In the case of powdered constituents which are reluctant to flow, scraper blades operated from outside the mixing chamber may sweep over the openings in the chamber wall.

When it is required to mix the contents of four supply containers the latter may be clamped to the underside of a common mixing chamber mounted for rotation about a vertical axis passing through the centre of gravity of the mixing chamber and the releasably attached containers.

According to a second aspect of the invention a mechanical mixer for mixing together the contents of supply containers comprises a common mixing chamber, mounting means for mounting the chamber for rotation on a vertical axis and for simultaneously allowing the chamber to perform a rocking motion about a horizontal axis, said axes intersecting art a point adjacent a lower wall of the chamber with respect to said vertical axis, at least two openings in said lower wall, on the same side of the horizontal axis and means for releasably clamping a respective supply container over each of said openings so that the interior of each container communicates with the interior of the chamber via one of the openings.

In the aforementioned aspects the invention is suitable for the mixing of freely flowing materials such as fine powders or liquids. In cases where one or more of the constituents are not freely flowable, it is desirable to supplement the mixing action by means of a stirrer blade operating within the mixing chamber but driven from outside it.

In this aspect the invention resides in a mechanical mixer comprising a mixing chamber, a rotary mounting allowing the chamber to perform a rocking motion about a horizontal axis at least two openings in the chamber wall on the same side of the horizontal axis, means for releasable securing the open mouths of mixture constituent supply containers to the openings, a stirrer device rotatable on a vertical axis within the mixing chamber adjacent said openings and means for rotating the stirrer device across the openings whilst the mixer is simultaneously rocked about said horizontal axis.

The geometric shape of the mixer is preferably similar to that defined in relation to the second aspect of the invention with four openings in the base of a cylindrical mixing chamber, and a stirrer peddle mounted for rotation by means of a drive shaft, passing through the upper wall of the mixing chamber.

In order that the invention may be better understood three rotary mixers embodying the several aspects of the invention will now be described in outline with reference to the accompanying drawings which are diagrammatic. In the drawings: Figure 1 shows a two constituent rotary mixture as it appears in elevation, Figures 2 and 3 show in elevation and plan outline respectively a four constituent mixer and Figures 4 and 5 show similar elevation and plan outline views of a four constituent mixer designed for materials which are less free flowing than those employed in the mixers of Figure 2 and 3.

In Figure 1 a mechanical mixer comprises a mixing chamber 1 mounted on trunnions 2 for rotation about a horizontal axis X-X. The chamber 1 is shaped as a truncated cone and its wider end merges with a yoke portion 3 having a pair of similar openings 4a, 4b in the chamber wall on the same side of the Axis X-X. Associated with the openings 4a, 4b are means 6 for releasably clamping cylindrical supply containers, or drums 5a, 5b which, when opened at one end, present orifices which match openings 4a, 4b. Thus when the containers are clamped to the openings 4a, 4b, the interior of each container communicates with the interior of the mixing chamber 1.By bringing the containers in an upright altitude to the mixer with its openings 4a, 4b directed vertically downwards, the containers can be clamped to the mixing chamber and the chamber put in communication with the container contents without first tipping the constituents out of their containers. The mixing chamber 1 is then rotated on its trunnions about the axis X-X and the contents of the containers 5a, Sb are initially tumbled into the mixing chamber 1 and then tumbled back and forth between the chamber 1 and the containers 5a, 5b. When mixing has been completed, the rotation is stopped and the mixing chamber brought to its starting position so that the containers are again upright. The containers, each of which now contain a portion of the mixture, are then detached from the mixing chamber 1 and fitted with temporary lids.

Referring to the embodiment of the invention shown in Figure 2 and 3 there is shown a four drum mixer in which the drums 10 containing the constituents to be mixed are temporarily connected to and communicate with a mixing chamber 11. The chamber 11 is mounted within a cage 12 which also supports the drums 10 and the cage is rotatable on a vertical axis Y-Y by means of a shaft 13 carried by an outer frame 14. The frame 14 is mounted in trunnions 15 on a horizontal axis X-X which intercepts the vertical axis Y-Y at a level just below the mixing chamber face adjacent the drums 10. Hence when the drums 10 are coupled to the mixing chamber these components may be rotated on the axis Y-Y and simultaneously rocked about the horizontal axis X-X.

In more detail an outer frame 14 has its trunnions 15 aligned on the axis X-X in trunnion bearings 16 mounted on staunchions 17. One or both staunchions also support a hydraulic rotary actuator and coupling 18 which is drivingly connected to the frame and, when energised, rocks the frame 14 about the horizontal axis X-X. Suspended from the upper part of the frame 14 on a thrust bearing 19 is a vertical shaft 13, the adjacent end of the shaft having a pulley 20 fixed to it. The pulley is driven by a belt drive 21 from an electric motor 22 mounted on the frame 14. The shaft 13 is thus rotatable on the axis Y-Y, normal to the axis X-X. Fixed to the shaft 13 is the inner cage 12 and within the inner cage is supported the mixing chamber 11 and drum support platforms 23.As shown, the shaft 13 extends through a tubular housing which penetrates the chamber 11 and terminates in a bearing housing member 14a on the outer frame 14.

The drum support platforms 23 are four in number and each is located beneath an aperture 24 in the lower wall of the mixing chamber 11 so that each drum with its lid removed, may engage a chamber aperture 24 and be temporarily coupled to the chamber whilst mixing takes place. Each platform 23 is supported by the cage but movable relative thereto vertically on a hydraulic jack 25 so that each drum; once on its platform, can be raised hydraulically to present its open top to the appropriate aperture in the mixing chamber 11. An annular seal 26 is then made to seal any gap between the aperture and the drum. Mixing is accomplished by the simultaneous rotation of the cage and the rocking motion imparted to the outer frame.

The mixer shown in Figures 4 and 5 is similar to that described and illustrated with reference to Figures 2 and 3 and the same reference numerals are used. However, the mixer of Figures 4 and 5 are not mounted for rotation about the vertical axis Y-Y although facility for rocking motion about axis X-X is preserved. In place of the rotation about Y-Y a rotary paddle 30 positioned within the mixing chamber and carried by a shaft 31 which extends vertically through the upper wall of the chamber where it is driven by a motor (not shown). In operation, four drums 10 are opened and clamped below the mixing chamber 11 as described with reference to Figures 2 and 3. The assembly is then rocked about the axis X-X with the object of spilling the drums' contents into the mixing chamber 11. To encourage the contents to flow and intermingle within the mixing chamber the stirrer device is operated causing the blade 30 to rotate in the mixing chamber. When mixing is completed the drums 10 are removed as before, each containing a proportion of the mixture.

Claims (6)

1. A mechanical mixer comprising a mixing chamber mounted for rocking or rotational movement about a horizontal axis, at least two openings in the chamber wall on the same side of the horizontal and means for releasably attaching a constituent supply container at each of said openings so that the interior of each container communicates with the interior of the mixing chamber via one of said openings.

2. A mechanical mixer as claimed in claim 1, comprising rotary paddles with the chamber for assisting mixing.

3. A mechanical mixer as claimed in claims 1 or 2, comprising scraper blades for sweeping over the opening in the chamber wall.

4. A mechanical mixer as claimed in any one of the preceding claims wherein the mixer is mounted for rotation about a vertical axis passing through the centre of gravity of the mixing chamber and releasably attached containers.

5. A mechanical mixer for mixing together the contents of supply containers comprising a common mixing chamber, mounting means for mounting the chamber for rotation on a vertical axis and for simultaneously allowing the chamber to perform a rocking motion about a horizontal axis, said axes intersecting art a point adjacent a lower wall of the chamber with respect to said vertical axis, at least two openings in said lower wall, on the same side of the horizontal axis and means for releasably clamping a respective supply container over each of said openings so that the interior of each container communicates with the interior of the chamber via one of the openings.

6. A mechanical mixer comprising a mixing chamber, a rotary mounting allowing the chamber to perform a rocking motion about a horizontal axis at least two openings in the chamber wall on the same side of the horizontal axis, means for releasable securing the open mouths of mixture constituent supply containers to the openings, a stirrer device rotatable on a vertical axis within the mixing chamber adjacent said openings and means for rotating the stirrer device across the openings whilst the mixer is simultaneously rocked about said horizontal axis.