The present invention relates to a mixer with a drum that comprises a mantle, a bottom and a top and which rotates around an axis of rotation. The present invention further relates to a method for heating the rotating drum of a mixer.
Such mixers are known from the state of the art and for example produced by the applicant of this patent application. These mixers are particularly utilized for dry mixing, for example of chemicals, food products or the like. In the past, these mixers have been indirectly heated, i.e. the heating medium does not get into contact with the product to be mixed, with water or oil as a heating medium. However, the maximum temperature up to which the mixer can be heated with these transfer media and/or the heat transfer is limited.
It was therefore the objective of the present invention to provide a mixer that can be heated to higher temperatures than mixers according to the state of the art and which is easy to build, to clean and/or to maintain.
This objective is attained with a mixer with a drum that comprises a mid-section, preferably a mantlee, which is closed by two end-sections, which are preferably located at both ends of the mixer, and which rotates around an axis of rotation, wherein the drum is indirectly heated with steam which condenses at least partially and wherein the condensate is collected in a collection pipe, wherein condensate is removed from the mid-section via the collection pipe, wherein the collection pipe (7) is connected to a condensate discharge, characterized in that the collection pipe is at least partially ring shaped, wherein the collection pipe is closed at one location, wherein at least one of the two end-sections comprises heating means. The present invention relates to a mixer, this mixer comprises a drum, which rotates around an axis of rotation, which is preferably arranged horizontally. The rotation of the drum can be continuous or discontinuous. The drum can rotate around the axis of rotation clockwise or counterclockwise. The drum of the mixer comprises a mantle, which is preferably shaped cylindrically and which is closed at both ends, for example with a column-plate. The drum is preferably made from steel, particularly from stainless-steel.
According to the present invention, the drum is heated indirectly with steam, i.e. the product to be mixed is, during the mixing process, never in contact with this heating-steam. During the heating of the drum, the steam condenses at least partially and this condensate is removed from the mixer without touching the product. The person skilled in the art understands, that steam can be added to the product inside the drum in case the recipe requires the addition of steam.
It is advantageously possible with the mixer according to the present invention to discharge the condensate from the mixer in a simple fashion without the need to employ moving parts such as a pump and/or a valve. Thus, a mixer with a simple construction and low weight is provided that has a long life time due to low maintenance requirements. By providing at least one of the two end-sections with heating means it is advantageously possible to further increase the contact surface of the drum with the product to be mixed and condensation and/or solidification of the product to be heated at the end sections can be avoided. The mid-section is hereinafter also called mantle of the drum.
Preferably, the drum comprises at least one, preferably a multitude of internal mixing means. Such an internal mixing means is for example a plate, which is preferably bent. Each internal mixing means is preferably fixed to the drum and more preferably co-rotates together with the drum. Even more preferred, the inventive mixer does not comprise any mixing means which move relative to the drum.
Preferably at least one such internal mixing means and/or the mantle of the drum are heated with steam. Preferably, each internal mixing means comprises one steam inlet and one condensate outlet. The mantle comprises preferably one two or more hollow segments which can be subjected to steam, preferably individually. In case water is used as a heat transfer medium, preferably two or more individual segments are provided. Preferably, the internal mixing means are at least partially hollow. In this hollow volume, the steam is injected and heats the sidewall of the internal mixing means. The mantle comprises preferably two sidewalls, preferably concentric sidewalls, which are spaced apart. In this hollow volume steam and/or water is injected, for example to heat and/or cool the inner sidewall of the mantle. In case of water as a heat transfer medium, the hollow volume between the sidewalls is preferably divided in two or more individual segments. Each segment extends preferably essentially over the entire length of the mantle and more preferably along only a part of the circumference of the inner sidewall. Each segment preferably comprises a steam-inlet and a condensate outlet. The segments are operated in parallel. These segments can be operated in series, for example, in case water is inserted into the hollow volume between the sidewalls.
In a preferred embodiment of the present invention, condensate is removed from each internal mixing means and/or the mantle via a collecting volume, preferably a collection pipe, which is connected to the condensate discharge of one, preferably each, internal mixing means and/or the condensate discharge from the mantle. The collecting volume co-rotates with the drum. Preferably, the collecting volume, preferably the collection pipe, has the same shape as the circumference of the mantle of the drum. More preferably, the collecting volume, preferably the collection pipe, is at least partially ring-shaped. In an even more preferred embodiment of the present invention, the cross section of the collecting volume, preferably the collection pipe, is closed at one position, at least partially. Preferably, one of the ends, more preferably both ends of the collecting volume, preferably the colleting pipe, are closed. Preferably, the collecting volume, preferably the collection pipe, extends at least partially, more preferably entirely beyond the circumference of the drum, i.e the distance of the colleting volume from the centerline is at least locally, preferably entirely, larger than the distance of the mantle of the drum from this centerline.
Preferably, the heating means is a hollow volume, wherein the hollow volume is provided for passing steam through. The injected steam heats a jacketed wall that forms the hollow volume of the at least one of the two end-sections of the drum, preferably the hollow volumes of both end-sections. The end-sections may be end-caps of the drum, preferably made from steel, in particular stainless steel. The hollow volume of the end-sections is preferably formed by two spaced apart walls, preferably parallel arranged walls that have a convex shape. In particular, the hollow volumes of one or both of the end-sections and the mantel are operated independently or in parallel, wherein each of said hollow volumes is heated to the same or a different temperature. In this way, the heating process can be tailored to the product to be heated. Preferably, the hollow volume of the at least one end-sections extends at least partially over the extent of the end-section in a direction perpendicular to an axis of rotational symmetry of the at least one end-section. It is thereby advantageously possible to heat the product to be mixed to a higher temperature as compared to a drum which comprises a hollow volume only in the mid-section or mantle. Preferably, the hollow volume of the end-section is arranged symmetrically around the axis of rotational symmetry of the end-section.
Preferably, the hollow volumes of the at least one end-section is connected with a hollow volume of the mid-section. Preferably, the condensate is removed from the hollow volume of the at least one end-section via the collection pipe, and preferably via the hollow volume of the mid-section. Preferably, both end-sections and the mid-section are all connected such that one hollow volume is formed for the circulation of steam and discharge of the condensate. It is thereby advantageously possible to discharge the condensate from the at least one end-section and the mid-section via the same discharge pipe and direct the condensate to the collection pipe which is connected with the discharge pipe. It is thereby advantageously possible to provide a mixer without moving parts, i.e. without a valve and/or a pump for the discharge of the condensate. Moreover, the mixer can be heated to a high temperature, because the condensate is removed continuously. Preferably, the mid-section has a cylindrical shape, wherein the axis of rotation preferably coincides with an axis of rotational symmetry of the mid-section. Preferably, the condensate is removed from the mid-section and one or both of the two end-sections at least once per revolution of the drum, i.e. once per rotation of 360 degrees around the axis of rotation. Preferably, the at least one end-section has a convex shape, wherein the axis of rotation preferably coincides with an axis of rotational symmetry of the at least one end-section. Preferably,a steam inlet pipe for feeding the drum with stem, a steam outlet pipe and a further condensate discharge pipe connected to the collection pipe are arranged along the axis of rotation of the drum.
Preferably, internal mixing means comprise a condensate collection area in which the condensate is collected before it is discharged. More preferred, the condensate collection area is tilted towards the condensate discharge.
The person skilled in the art understands that, the mixer can also be heated or cooled with water and/or any other fluid medium, wherein the water or other fluid medium is discharged from the mixer in the same way as the condensate is discharged. In this case, i.e. when the mixer is heated or cooled with water and/or oil, in the entire disclosure the subject matter “steam” and “condensate” has to be substituted by the subject matter “water and/or oil and/or any other fluid medium”. Particularly, the steam inlet is the water/oil-inlet, whereas the condensate outlet, the condensate collection and/or condensate discharge is the water/oil outlet, water/oil collection and/or the water/oil discharge.
Another subject matter of the present invention is a method for heating the rotating drum of a mixer, with steam, whereas condensate is removed from the mixer discontinuously.
The disclosure made regarding the inventive mixer also applies to the inventive method and vice versa.
According to inventive method of the present invention, the condensate is removed from the mixer discontinuously. Preferably, the discharge takes only place in certain rotational positions of the drum, preferably limited to a rotational segment of <180°, more preferably <150° and even more preferably <120° and even much more preferred <90°.
According to another or a preferred embodiment of the present invention, the condensate is discharged from the mixer, from the internal mixing means and/or from the mantle at least temporarily, preferably entirely, by gravity, i.e. no pump is needed to discharge the condensate.
The disclosure made regarding the inventive mixer and the inventive method also applies to this inventive method and vice versa.
According to a preferred or another embodiment of the present invention, the mixing means and/or at least a segment of the mantle of the drum is heated with steam and the condensate is removed from the mixer and/or from the internal mixing means and/or from the mantle and/or only once per rotation of the drum. The disclosure made regarding the inventive mixer and the inventive method also applies to this inventive method and vice versa.
The inventions are now explained according to
The operation of the inventive mixer is as follows:
The mixing material is added and discharged to the drum 10 continuously or batchwise. During the mixing the drum 10 rotates here counter-clockwise as depicted by arrow 11. In order to heat drum 10, steam is supplied via the steam inlet 12. From there the steam flows via pipe 12.4 to the here ring-shaped, steam distribution pipe 12.1. To this steam distribution pipe 12.1 a multitude of pipes 12.3, 12.2 are connected, which supply the steam to the internal mixing means 6 and/or the segments of the hollow mantle, respectively. This steam condenses in the internal mixing means 6 and/or in the mantle 2. This condensate is removed from the individual internal mixing means 6, when its condensate discharge pipe 8 is in a position approximately between 7 and 5 o'clock. The condensate from the mantle is discharged, when the condensate discharge pipe 9 of the mantle is in a rotational position between 7 and 5 o'clock. In these positions, the condensate flows from the internal mixing means 6 and from the hollow volume in the mantle into the condensate collection pipe 7. Since the cross section of this pipe 7 is closed at least partially at position 16, the collected fluid is pushed upwards during the rotation of the pipe and once the discharge pipe has reached approximately the 2 o'clock-position, the collected fluid is discharged via this pipe 7.2 to the ambient. The discharge takes place until the discharge pipe 7.2 has approximately reached the 12 o'clock-position. During the subsequent rotation of the drum, the discharge is repeated. A person skilled in the art understands that during one entire rotation of drum 10, each internal mixing means 6 and each segment in the mantle 2 is emptied from condensate only once. No pump is needed for the discharge of the condensate. Once the condensate in the collection pipe 7 has been lifted over a certain height in the collection pipe 7, due to the rotation of the collection pipe 7, the discharge takes place by gravity.
1 mixer
2 mantle, mid-section
3 first end, end-section
4second end, end-section
5 axis of rotation, axis of rotational symmetry
6 internal mixing means, scoop, shovel
6.1 condensate collection area
7 condensate collecting volume, condensate collection pipe
7.1 ends of the condensate collection pipe
7.2 discharge of the condensate collection pipe
7.3 steam discharge
8 condensate discharge of the mixing means 6
8.1 downward slope
9 condensate discharge of the mantle
10 drum
11 direction of rotation
12 steam inlet
12.1 steam distribution pipe
12.2 steam supply to internal mixing means 6
12.3 steam supply to the mantle 2 of the drum 10
12.4 supply from the steam inlet 12 to the distribution pipe 12.1
13 valve
14 support
15 inspection-, cleaning-opening
16 at least partial closing of the inner diameter of the pipe
17 hollow volume
18 jacketed wall
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/EP2013/056376 | 3/26/2013 | WO | 00 |