EP0142003B2 - Batch mixer - Google Patents

Abstract

Apparatus for mixing charges of flowable solid materials has a hollow cylindrical housing with two upright end walls and a hollow shell between the end walls. The lower part of the shell has a large material evacuating opening sealable by two mirror symmetrical doors which are pivotable about horizontal axes. The opening extends all the way between the end walls and is large enough to allow for gravitational outflow of the entire contents of the housing irrespective of the angle of repose of the charge. The doors are bounded by edge faces which make oblique angles with their external surfaces and abut against complementary edge faces of the end walls and shell. Sealing strips on the shell and end walls are engaged by deforming members at the external surfaces of the doors when the opening is closed. The abutting edge faces of the doors also make oblique angles with the respective external surfaces.

Description

The invention relates to a batch mixer with an approximately drum-shaped housing and preferably with a horizontal mixing shaft, the lower wall area of which is designed as at least one opening flap which can be pivoted about a pivot axis for emptying.

Such a batch mixer is known from CH-A-349 477. The lower part of this batch mixer is designed as a folding door. However, the sealing of this folding door must be regarded as difficult and expensive due to its considerable size, but is not explained in this document. Furthermore, it is not specified that the opening angle of the opening closed by this folding door is greater than the angle of repose of the mixed material. Due to the size relationships that result from the drawing of this document, it is at most disclosed that the opening angle is smaller than the slope angle of dry mix, so that when emptying mix remains in the mixer housing and can only be removed by additional measures.

EP-A-0 105 107 (filing date: July 20, 1983; priority October 5, 1982; publication date: April 11, 1984) describes a mixing device to which a batch mixer of the type mentioned at the beginning belongs, in which the opening angle is greater than the slope angle of the mix and the opening flap extends from the front to the front of the housing. This is an older, but later published publication. The batch mixer provided here has the considerable advantage, particularly with regard to its emptying, that cleaning after emptying the material to be mixed is not necessary. This is achieved by the angle of repose of dry bulk material which exceeds the large opening angle, because no mixture can remain within the open housing of this mixer. A different mixture can be processed than the closing of the opening in the mixer without this previous mixture being impaired or influenced.

FR-A-1 329 058 also discloses a drum-shaped mixer with a polygonal cross section of the mixer housing and two jaw-shaped slide valves which can be opened in the form of a jaw, the entire mixer housing being rotated during the mixing process. It is a concrete mixing machine with which a mix is to be mixed with water, so that a material-specific slope angle is irrelevant. Furthermore, the problem that mixtures of different compositions should be able to be produced in succession plays no role. without a previous mixture falsifying the next one in its composition.

Batch mixers for dry goods have a relatively high internal pressure, especially if the mixer is of a suitable size for good performance. Numerous batch mixers are therefore also known from practice which have only relatively small openings so that they are not subjected to correspondingly high forces. Even then, residue-free emptying is not possible without additional cleaning measures.

There is therefore the task of creating a batch mixer of the type mentioned, in which, despite high forces, such a large opening is possible in its interior that residue-free emptying is possible without additional cleaning measures, the large opening being securely sealed and should be able to be closed and the longest possible service life should be achieved.

To solve this problem, the batch mixer of the type mentioned with a lower openable wall area is characterized in that the opening angle is greater than the angle of repose of the material to be mixed and the opening flap extends from face to face of the housing, that at least that located in the region of the pivot axis of the opening flap , horizontally extending narrow side of the flap is oblique in cross-section and encloses an acute angle between itself and the outside of the opening flap, that the housing opening has a matching counter slope as an attachment for the sloping narrow side of the flap when the opening flap is closed and that in the area of this narrow side on the housing at one of the A seal that is operatively connected to the closed opening flap is arranged inside the housing.

The oblique design of the upper horizontal narrow side of the opening flap ensures that when opening the flap this narrow side does not get into a horizontal, but rather a corresponding oblique position, so that no material can remain on it, which prevents the tight fitting when the flap is closed could. In addition, such an inclined joint has a better sealing effect overall, which is further improved and supported by the sealing strip.

It is possible that the sealing strip is embedded in the counter-bevel of the mixer housing, so that the oblique narrow side of the opening flap directly contacts this seal in the closed position.

A particularly favorable embodiment of the invention, in which a seal can also be achieved if the inclined surface on the narrow side of the flap should be worn out by draining material, can consist of being adjacent on the outside of the housing to the counter slope, the sealing strip is arranged or embedded, and a pressure and counter strip that engages over this seal in the closed position is attached to the outside of the flap.

Furthermore, it is of course also possible for a corresponding sealing strip, in particular, to be embedded in a groove both on the oblique narrow side and on the outside of the housing. In any case, the sealing strip is located opposite the mix on a "shadow side" of the housing, so that it is not acted upon by the mix when it is discharged. Compared to labyrinth seals in the joint area, there is the advantage of a much simpler production with a good sealing effect, which is not reduced by a certain amount of wear.

The counter bar can be exchangeably and adjustably attached, in particular releasably, to the outside of the flap. This counter bar does not hinder the opening process if the pivot axis for the flap is arranged outside the housing and above the sealing joint. During the pivoting movement, the surfaces lying against one another then detach from one another before they are also pivoted away from one another. Conversely, when they close, they rest against each other practically without mutual friction.

Since a very large opening of the mixer housing must be kept closed in a dust-tight manner, it is particularly advantageous if two approximately symmetrically arranged flaps are provided which have sloping narrow sides in their contact area which abut one another in the closed position. Again, on the flap, the inclined surface of which forms an obtuse angle with the outside, a sealing strip in an area facing away from the material closure, which cooperates with the other flap and its sealing surface.

It is also particularly expedient in such an embodiment with two wing-like flaps if the sealing strip is incorporated next to the inclined surface of the flap and the flap with the acute-angled bevel on the outside preferably carries a mating strip for engaging the sealing strip. Especially this counter bar is exposed to a certain material closure when the flap is opened, so that it is advantageous if it can be replaced.

On the flap end faces, the narrow sides of the flap can in turn be formed obliquely in such a way that the outside of the flap forms an acute angle with the narrow side, and on the container housing, the end wall can have a matching oblique counter surface all around on the circumference, which is pointed between the outside and the oblique surface Angle. When the flaps are closed, they are miter-jointed on these end walls.

In addition to the oblique contact surfaces for the flaps on the end face, an outer housing wall section can also be provided, which projects downward beyond the flap end face. This stabilizes the entire housing in this area.

Furthermore, a sealing strip arranged in the circumferential direction can be fastened between the inclined surface and the outer housing wall, and the flaps can preferably have interchangeable counter strips on their outer sides, which in the closed position bear against these sealing strips running in the circumferential direction.

It results from a combination of the features and measures described above that sealing strips are arranged around the housing opening in places that are not touched by the outflowing material, preferably embedded, which are overlapped by counter strips on the flap (s) in the closed position and below in their receiving groove or the like seat directed sealing pressure are set. In addition to the counter strips on the flaps, the seals can also be interchangeably clamped in grooves.

Above all, the combination of the inclined contact surfaces in all sealing areas, in which the helix angles are set so that the flap increases in size from the inside to the outside, with the seals and sealing strips results in a very simple construction, which also opens and closes the flap is allowed in a conventional manner without additional movement components, but the seals are nevertheless protected against the strongly eroding material, so that the seal is retained for a long time.

As a further embodiment, it is expedient if the flap shape can be adjusted, in particular in the area of the sealing strips, in the sense of a largely uniform sealing effect. This can compensate for the loads on the flap, which could lead to loosening of the seal seat in certain areas.

It is particularly expedient if stiffening arms are arranged next to one another along the length of the flap along the length of the flap and have fastening points between them and the outside of the flap for spacer plates that can be used there. Depending on the load and deformation of the flaps, more or less spacer plates can be placed on the individual arms in order to have a secure system everywhere, even with heavy loads or deformation. It is particularly advantageous if the support arms for the flap have an angular or T-shaped cross-sectional profile, with an angle leg or the T-crosspiece engaging the flap and allowing the spacer plates to be inserted between them and the flap.

Despite a very large emptying opening, there is a simple construction, which can also be used with a dry mix with dust Proportions a secure seal is allowed even after a long period of operation. Nevertheless, the construction is simple and can be done with conventional actuating means such. B. working cylinders that operate the opening flaps work.

• Figur 1 eine Seitenansicht und
• Figur 2 eine Stirnansicht eines erfindungsgemäßen Mischers,
• Figur 3 in vergrößertem Maßstab die Ausbildung der Dichtungsfuge zwischen einer Öffnungsklappe und dem Mischergehäuse im Bereich einer Schwenkachse,
• Figur 4 einen Teil-Längsschnitt mit der Ausbildung der stirnseitigen Anlageflächen an den Öffnungsklappen und dem Gehäuse,
• Figur 5 die Abdichtung zweier flügelartig angeordneter und sich ergänzender Öffnungsklappen im Querschnitt in Schließstellung.
• Figur 6 in Seitenansicht die Befestigung eines an der Schwenkachse einer Öffnungsklappe befestigten Stützarmes mit dieser Klappe und dazwischen befindlichen Distanzblechen sowie
• Figur 7 eine Seitenansicht zweier Stützarme gemäß Fig. 6 mit Schwenkachse und Öffnungsklappe.

The invention is described in more detail below with its details that are essential to it, using the drawing. It shows in a partially schematic representation:

• Figure 1 is a side view
• FIG. 2 shows an end view of a mixer according to the invention,
• FIG. 3 shows, on an enlarged scale, the formation of the sealing joint between an opening flap and the mixer housing in the region of a pivot axis,
• FIG. 4 shows a partial longitudinal section with the formation of the end contact surfaces on the opening flaps and the housing,
• Figure 5 shows the seal of two wing-like and complementary opening flaps in cross section in the closed position.
• Figure 6 in side view of the attachment of a support arm attached to the pivot axis of an opening flap with this flap and spacer plates located in between and
• 7 shows a side view of two support arms according to FIG. 6 with pivot axis and opening flap.

A batch mixer designated as a whole has a horizontal mixing shaft 2, which is acted upon by a coaxial drive motor 3 and is accommodated in a drum-shaped housing 4 according to FIG. 2. In this case, the lower wall area of this housing 4 can be opened for drainage, two opening flaps 5 being pivotable to one another and away from one another like wings. These opening flaps 5 practically form the lower wall area of the housing 4. They are so large that the opening angle of the housing opening is larger than the slope angle of dry mix. 1, the opening flaps 5 run from the front to the front of the housing 4. In this way, complete emptying of a mixer is possible without additional cleaning measures, because when the opening flaps 5 are opened, the dry mix from the mixer, for example, initially falls into an intermediate funnel 6 can, without projections or the like. On which residues of mixed material could remain.

In order on the one hand to achieve a high level of tightness, on the other hand to achieve a simple and inexpensive construction and to prevent 5 mixed material from remaining on the narrow sides of the opened opening flaps. 3, the upper horizontal narrow valve sides 8 located in the joint area or in the region of the pivot axis 7 of the pivotable opening flap 5 are formed obliquely in cross-section, an acute angle being formed between the narrow side 8 and the outer side 9 of the opening flap 5, for example in can be of the order of 55 °. The housing opening has a matching counter bevel 10 as a contact surface for the sloping narrow flap side 8 when the opening flap 5 is closed, as shown in FIG. 3. In addition, in the region of this narrow side 8 on the housing 4 at a point remote from the interior of the housing, a seal 11 which is operatively connected to the closed opening flap 5 is arranged. The seal 11 designed as a sealing strip could be embedded in the counter-bevel 10 of the mixer housing 4, so that the oblique narrow side 8 would contact the seal 11 in the closed position. With such an arrangement, the seal 11 is already on a “shadow side” in relation to the mixture flowing out. In the exemplary embodiment, however, it is provided that the sealing strip 11 is arranged on the outside of the housing 4 adjacent to the counter bevel 10 and is inserted into a groove 12 a and on the outside 9 of the opening flap 5 a pressure and counter strip 12 which overlaps this seal 11 in the closed position is attached. This counter bar 12 is detachable and exchangeable and also adjustable by means of screws 13. With this arrangement, the sealing strip 11 can practically not come into contact with the mix and be adversely affected by it, although it is arranged at a point where it could be very easily attached and, if necessary, also replaced.

The counter bar 12 can not hinder the opening process of the opening flap 5, since the pivot axis 7 for this flap 5 is arranged outside the housing 4 and above the sealing joint formed by the inclined surfaces 8 and 10 on the one hand and the seal 11 and the counter bar 12. During the swiveling movement around the axis 7, the surfaces lying against one another first detach before they are swiveled away from one another. Conversely, when they close, they lay against each other practically without mutual friction.

5 shows the contact area of the two symmetrical opening flaps 5 and the seal provided there. The opening flaps also have sloping narrow sides 14 in their contact area and the opening flap 5, the sloping surface 14 of which forms an obtuse angle with the outside 9, has a sealing strip 11 in a region facing away from the mix, which cooperates with the other opening flap and its sealing surface. It is also provided in this case that the sealing strip 11 is incorporated next to the inclined surface 14 of the flap 5 and the flap 5 with the acute-angled inclined surface 14 on its outside carries a counter strip 12 for application to the sealing strip 11, which in turn can be replaced by means of screws 13 and is also adjustable. This counter bar 12 in the contact area of the two opening flaps 5 can be exposed to a certain flow of material when the flaps are opened, so that they may be wears out faster, so it is advantageous if it can be replaced quickly.

The seal in the area of the end faces of the mixer 1 is illustrated particularly in FIG. 4. On the end walls 15, in turn, inclined surfaces 16 can be seen which form an acute angle with respect to the outside 17. The opening flaps also have an inclined surface 18 in this area, which runs at an acute angle to the outside thereof, the two inclined surfaces 16 and 18 matching each other in such a way that the closed opening flap 5 is mitred with this end wall region, as is the right part of the figure Fig. 4 illustrates.

In addition to these inclined contact surfaces 16 for the opening flaps 5, an outer housing wall section 19 is also provided, which projects downward beyond the flap end faces. This can pass into the funnel 6.

A sealing strip 20, which is arranged in the circumferential direction in accordance with the curvature of the opening flaps 5, is fastened between the inclined surfaces 16 and the outer housing wall 19, wherein this sealing strip 20 can be embedded in a corresponding groove 21. Interchangeable counter strips, which bear against these sealing strips 20 in the closed position, can in turn be attached to the flap outer sides. In the right part of FIG. 4, these counter strips running parallel to the end faces are not visible, since they are covered by the longitudinal section through the counter strip 12 at the opening area of the two flaps. However, they can be connected directly to this sealing strip 12 on the end faces.

It follows that sealing strips 11 and 20 are arranged and embedded around the very large housing opening at all points that are not touched by the outflowing material, which overlap with counter strips 12 on the flaps 5 in the closed position and under in their receiving groove 12 or 21 directional seal pressure. These sealing strips can also be replaced if they have aged or their sealing effect is weakening for other reasons. Elaborate labyrinth seals u. The like are avoided. This results in a mixer housing 4, which is dust-tight and maintains its tightness even at high pressures during the mixing process, but nevertheless has a very large outlet opening.

Because of the high forces during the mixing process and the resulting, possibly uneven loads and the large area of the opening flaps 5 is also provided in the embodiment. that the flap shape is adjustable, in particular in the area of the sealing strips 12 and 21 in the sense of a largely uniform sealing effect. It can be seen in FIG. 1 that stiffening arms 22 are arranged next to one another at a distance from the joint axis 7 over the length of the opening flaps 5. These are connected to the opening flaps 5 in a manner yet to be described and transmit the forces from working cylinders 23 to the flaps. these cylinders 23 according to FIG. 2 each engage with a lever arm 24 on the hinge axis 7.

Between themselves and the flap outside 9, the stiffening arms 22 have fastening points for spacer plates 25 that can be used there. Depending on the load and deformation of the opening flaps 5, more or fewer spacer plates 25 can be placed on the individual arms 22 in order to prevent deformations occurring during manufacture or under load to compensate for the opening flaps and to create a secure system everywhere, especially in the sealing area.

According to FIGS. 6 and 7, the support arms 22 can have an angular or T-shaped cross-sectional profile, an angle leg or the T-crosspiece engaging the flap 5 and allowing the spacer plates 25 to be inserted between them and the flap. This is a very simple and functional design for bracing and adapting the flaps to high loads or to compensate for any deformations that may occur.

Overall, there is a batch mixer 1 which has such a large discharge opening that no mixture residues remain in its interior when the opening flaps 5 are opened with the aid of the working cylinders 23. Thus, after a portion of the mixture has been prepared, a new mixture can be mixed immediately afterwards without loss of time due to cleaning or the like or the new mixture being falsified by constituents from the previous mixture. When used in the production of dry mortar, this leads to the fact that a mixing plant for the production of such mortar or plaster without an intermediate container can get along with correspondingly expensive loading devices and emptying devices, since arriving vehicles in different orders can be individually filled with the desired mixture without that stocks of these various mixtures must be available.

Claims (16)

1. A batch mixer (1) having an approximately drum-shaped housing (4) and further having a preferably horizontal mnixing shaft (2), the lower wall area of said housing being devised for discharge in the form of at least one opening flap (5) adapted to be swivelled about a swivel axis (7), characterized in that the opening angle is larger than the angle of slope of the material to be mixed and the opening flap (5) extends from end face to end face of the housing (4), that at least the horizontally extending narrow side (8) located in the region of the swivel axis (7) of the opening flap (5) is of slanting configuration in cross section and forms between itself and the outside (9) of the opening flap (5) an acute angle, that the opening of the housing has a matching counter slant (10) as abutment for the slanting narrow side (8) when the opening flap (5) is closed and that in the region of said narrow side (8) there is disposed on the housing (4) at a point turned away from the housing interior a packing (11,20) co-operating with the closed opening flap (5).
2. The mixer as claimed in claim 1, characterized in that the packing strip (11) is inserted in the counter slant (10) of the mixer housing (4).
3. The mixer as claimed in claim 1 or claim 2, characterized in that a packing strip (11) is disposed or inserted on the outside of the housing (4) adjacent to the counter slant (10) and a contacting and mating strip (12) is attached to the outside (9) of the flap (5) and engages over said packing (11) in the closed position.
4. The mixer as claimed in claim 3, characterized in that the mating strip (12) is attached to the outside (9) of the opening flap (5) in a replaceable and adjustable manner, in particular in a detachable manner.
5. The mixer as claimed in any one of claims 1 to 4, characterized in that the swivel axis (7) for the opening flap (5) is located outside the housing (4) and above the joint.
6. The mixer as claimed in any one of the preceding claims, characterized in that provision is made for two approximately symmetrically disposed opening flaps (6) having in their contacting area slanting narrow sides (14) which are in abutment in the closed position.
7. The mixer as claimed in claim 6, characterized in that the opening flap (5) whose slant (14) forms an obtuse angle with the outside (9) has a packing strip (11) in a region turned away from the material to be mixed, said packing strip (11) co-operating with the other opening flap (5) and the sealing surface thereof.
8. The mixer as claimed in claim 6 or claim 7, characterized in that the packing strip (11) is incorporated next to the slant (14) of the opening flap (5) and the opening flap (5) having the acute-angled slant (14) bears on its outside (9) a mating strip (12) for abutment against the packing strip, said mating strip preferably being replaceable.
9. The mixer as claimed in any one of claims 1 to 8, characterized in that on the end faces of the flaps the narrow sides (18) are of slanting configuration so as to form an acute angle with the outside (9) of the flap (5) and that on the container body the end wall (15) has a matching counter face (16) having an acute angle between the outside and the slant.
10. The mixer as claimed in claim 9, characterized in that an outer wall portion (19) of the housing is provided next to the end slanting abutment (16) for the opening flap (5), said wall portion projecting downwardly beyond the end face of the flap and preferably turning into a funnel (6).
11. The mixer as claimed in claim 9 or claim 10, characterized in that a packing strip (20) disposed in the circumferential direction is interposed between the slant (16) and the outer wall portion (19) of the housing, and the opening flaps (5) have on their outside mating strips which are preferably replaceable and in the closed position abut against said packing strips (20).
12. The mixer as claimed in any one of the preceding claims, characterized in that packing strips (11, 20) are disposed, preferably inserted, all around the housing opening at points not contacted by discharged material, said packing strips being overlapped in the closed position by mating strips on the opening flap(s) (5) and being under sealing pressure directed into their receiving groove (12a, 21) or similar seat.
13. The mixer as claimed in any one of claims 3 to 12, characterized in that both the mating strips (12) and the packings (11, 20) are inserted or clamped in grooves (12a, 21) in a replaceable manner.
14. The mixer having a discharge opening which extends over a large peripheral area and from end face to end face and is closed by at least one flap, as claimed in any one of the preceding claims, characterized in that the shape of the opening flap(s) is adjustable in particular in the region of packing or the like to obtain a largely uniform sealing effect everywhere.
15. The mixer as claimed in any one of claims 1 to 14, characterized in that stiffening arms (22) are juxtaposed in spaced relationship from the swivel axis (7) over the length of the opening flap (5), said stiffening arms having between them and the outside (9) of the opening flap (5) mounting points or the like for spacing means insertable there, in particular spacer plates (25).
16. The mixer as claimed in claim 15, characterized in that the stiffening arms (22) for the opening flaps (5) have an angular or T-shaped cross section, one angle side or the T-cross bar engaging the opening flap (5) and permitting spacing means, preferably spacer plates (25), to be interposed between them and the opening flap (5).

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