U.S. patent number 3,880,407 [Application Number 05/407,040] was granted by the patent office on 1975-04-29 for mixer and kneader with counteractive blades.
Invention is credited to Heinz List.
United States Patent |
3,880,407 |
List |
April 29, 1975 |
Mixer and kneader with counteractive blades
Abstract
In a mixer and kneader, an axially extending agitator rotates
within a stationary cylindrically-shaped housing. In a number of
axially spaced radially extending planes within the housing,
plate-like elements are fixed to the agitator and are closely
spaced inwardly from the inner surface of the housing. Each plane
has a number of circumferentially spaced plate-like elements and
each element has an axially extending stirrer blade attached to its
radially outer edge. Between each adjacent pair of planes of the
plate-like elements, a counter element is provided consisting of a
support mounting attached to the inner wall of the housing and an
axially extending counter blade secured to the radially inner
surface of the support mounting. The stirrer blades are arranged to
pass between the cylindrical housing and the counter blades
affording a kneading action. Further, the stirrer blades afford a
scraping action on the inner surface of the cylindrical housing
while the counter blades afford a similar scraping action on the
plate-like elements and the surface of the agitator. The counter
blades can be formed in a frame-like configuration to provide
additional kneading action.
Inventors: |
List; Heinz (Pratteln,
CH) |
Family
ID: |
33477344 |
Appl.
No.: |
05/407,040 |
Filed: |
October 17, 1973 |
Foreign Application Priority Data
|
|
|
|
|
Oct 18, 1972 [CH] |
|
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15339/72 |
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Current U.S.
Class: |
366/99;
366/325.5; 366/309; 422/225 |
Current CPC
Class: |
B01F
15/068 (20130101); B01F 7/048 (20130101); B01F
15/065 (20130101) |
Current International
Class: |
B01F
7/02 (20060101); B01F 7/04 (20060101); B01f
007/04 () |
Field of
Search: |
;259/9,10,5,DIG.18,6,7,25,26,21,22,45,46,109,110 ;165/94
;23/252R,285 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Jenkins; Robert W.
Attorney, Agent or Firm: Toren, McGeady and Stanger
Claims
What is claimed is:
1. A mixing and kneading device for the mechanical, chemical and
thermal treatment of liquid, pasty and pulverant products with or
without the input or output of gases and vapor, comprising a
cylindrical housing, an inlet in said housing for introducing
materials to be processed into said housing, an outlet in said
housing spaced from said inlet for withdrawing the materials from
said housing, an agitator positioned within and having its axis
extending in the axial direction of said housing, said agitator
mounted for rotation about its axis, a plurality of plate-like
elements secured to and extending radially outwardly from said
agitator for rotation therewith, said plate-like elements disposed
in a number of planes extending transversely of the axis of said
agitator, a stirrer blade extending in the axial direction of said
agitator and fixed to each said plate-like element on the radially
outer periphery thereof, the radially outer periphery of said
plate-like elements being spaced closely inwardly from the inner
surface of said cylindrical housing so that as said agitator
rotates at least said stirrer blade passes in closely spaced
relation to the inner surface of said cylinder housing and effects
a cleaning thereof, a plurality of stationary counter-elements
secured to the inner surface of said cylindrical housing and
extending radially inwardly towards said agitator, each said
counter-element comprising a mounting support secured to the inner
surface of said cylindrical housing and extending radially toward
said agitator for a dimension at least slightly greater than the
dimension between the inner surface of said cylindrical housing and
the radially-inwardly facing surface of said axially extending
stirrer blades, said mounting support being positioned in the axial
direction of said cylindrical housing so that it is positioned
between the adjacent ends of said stirrer blades located in
adjacent planes of said blades, a counter-blade secured to the
radially inner end of said support mounting and extending inwardly
therefrom toward said agitator so that the radially inner edge of
said counter-blades is spaced closely from and acts as a scraper
for said agitator, said counter-blades extending in the axial
direction of said cylindrical housing from said support mounting
into the axially extending portion of said cylindrical housing in
which said stirrer blades rotate so that said stirrer blades pass
between the inner surface of said cylindrical housing and the
radially outwardly facing edge of said counter-blades and spaced
axially from said support mountings for said counter-blades for
providing a kneading effect.
2. A mixing and kneading device, as set forth in claim 1, wherein
each said stirrer blade is fixed to one said plate-like element
with its radially outer edge being approximately coincident with
the radially outer edge of said plate-like element.
3. A mixing and kneading device, as set forth in claim 1, wherein
each said stirrer blade is fixed to and extends radially outwardly
from the radially outer edge of said plate-like element so that
there is a radially extending open space between the radially outer
side of said plate-like element and stirrer blade.
4. A mixing and kneading device, as set forth in claim 1, wherein
said stirrer blades extend in parallel relation with the axial
direction of said cylindrical housing.
5. A mixing and kneading device, as set forth in claim 1, wherein
said stirrer blades are arranged angularly to the axial direction
of said cylindrical housing.
6. A mixing and kneading device, as set forth in claim 1, wherein a
number of radially extending planes of said plate-like elements are
arranged along said agitator with a plurality of said plate-like
elements in each of the radially extending planes and one said
counter element located between each pair of adjacent said radially
extending planes.
7. A mixing and kneading device, as set forth in claim 6, wherein
at least two circumferentially spaced counter-elements are located
between each pair of adjacent said radially extending planes of
said plate-like elements.
8. A mixing and kneading device, as set forth in claim 7, wherein
each said counter-element has its said counter blade extending in
the axial direction from only one side of said mounting support and
on adjacent said counter-elements between the same pair of radially
extending planes of said plate-like elements said counter-blades
extend in opposite directions.
9. A mixing and kneading device, as set forth in claim 6, wherein
said counter-blade extends laterally from said support mounting in
the axial direction of said cylindrical housing for a dimension so
that it is closely spaced from at least one said plate-like element
in the adjacent planes of said plate-like elements for affording a
scraping or cleaning action on the surface of said plate-like
element.
10. A mixing and kneading device, as set forth in claim 9, wherein
said counter-blades extend in parallel relation with the axial
direction of said cylindrical housing.
11. A mixing and kneading device, as set forth in claim 9, wherein
said counter-blades have a curved configuration viewed in the plane
of said plate-like elements.
12. A mixing and kneading device, as set forth in claim 9, wherein
said counter-blades have a frame-like shape forming a kneading
opening therethrough.
13. A mixing and kneading device, as set forth in claim 12, wherein
the frame-like shape of said counter-blades is formed by an axially
extending kneader arm secured to and extending in the axial
direction from both sides of said mounting support, a pair of
axially spaced arms each extending radially outwardly from an
opposite end of said kneader arm toward said agitator and a scraper
extending between the radially inner ends of said arms and having
its radially inner surface spaced closely from the surface of said
agitator, the radially outer side of said scraper being spaced
radially from the radially inner side of said kneader so that said
kneader arm, said arms and said scraper define the kneading opening
through said counter-blades.
14. A mixing and kneading device, as set forth in claim 1, wherein
said counter-blades extend at an angle to the axial direction of
said cylindrical housing.
15. A mixing and kneading device, as set forth in claim 1, wherein
said cylindrical housing having displaceable panels and said
counter-elements attached to said displaceable panels so that said
panels can be removed for cleaning the interior of the device.
16. A mixing and kneading device, as set forth in claim 1, wherein
one of said agitator and said housing is subjected to a vibratory
action having an amplitude of one-half to three-quarters of the
clearance between the moving parts of said rotatable agitator and
the stationary parts of said housing.
17. A mixing and kneading device, as set forth in claim 1, wherein
said plate-like elements are arranged in a number of axially spaced
radially extending planes having said plate-like elements spaced
apart in the circumferential direction of said agitator within each
of said radially extending planes so that open spaces are provided
between adjacent edges of said plate-like elements.
18. A mixing and kneading device, as set forth in claim 1, wherein
said cylindrical housing having a closed end wall at each end
thereof and at least one said plate-like element located in a plane
closely adjacent to each said end wall and having one said stirrer
blade fixed to said plate-like element in the plane adjacent the
end wall and extending axially therefrom only from the side of said
plate-like element facing away from the adjacent said end wall.
Description
SUMMARY OF THE INVENTION
The present invention is directed to a mixer and kneader and, more
particularly, it is directed to the arrangement of counteracting
blades so that materials can be thoroughly mixed and kneaded.
The mixer and kneader of the present invention uses counteracting
blades for the mechanical, chemical and thermal treatment of
liquid, pasty and pulverulent products, with or without the input
or output of gases and vapors, so that a satisfactory exchange of
material is achieved in all phases. The mixer and kneader is formed
of a rotatable agitator mounted within a stationary,
cylindrically-shaped housing. In a number of axially spaced
radially extending planes within the housing, a plurality of
plate-like elements are secured to the agitator and extend
outwardly to a point closely spaced from the inner surface of the
housing. A stirrer blade is fixed to the radially outer edge of
each of the plate-like elements and the blade extends in the axial
direction. Positioned between each pair of adjacent planes of
plate-like elements is a stationary counter element secured to the
housing by means of a support mounting with a counter blade
attached to the mounting at the point spaced inwardly from the
inner surface of the housing. The counter blade extends in the
axial direction in generally the same manner as the stirrer blades.
The stirrer blades, during rotation, pass between the counter
blades and the inner surface of the housing and afford a scraping
or cleaning effect on the housing wall and, in combination with the
counter blades, a kneading effect on the material within the
housing. Similarly, the counter blades provide a cleaning or
scraping effect on the surface of the agitator and also on the
axially facing surfaces of the plate-like elements.
Nowadays frequent use is made of paddle dryers for chemical
reactions and thermal processes. Such dryers consist of a
horizontally arranged cylindrical housing provided with a revolving
agitator on which agitator arms having blade-like extremities are
fixed. The use of such machines is limited basically because of the
inadequacy of the mixing and kneading action, that is, the
interchange of the material when it is in the pasty state.
Moreover, only about half of the heated surfaces in such dryers are
continuously cleaned and, as a result, the heat transfer within the
dryer is impaired.
As compared to the prior art, in the present invention, it is
possible to increase the heat transfer surface and to raise the
coefficient of heat transmission through such surfaces by affording
a continuous cleaning action of the surfaces. Furthermore, it is
also possible to provide a satisfactory kneading effect even when
the materials being processed are in the pasty state.
The various features of novelty which characterize the invention
are pointed out with particularity in the claims annexed to and
forming a part of this disclosure. For a better understanding of
the invention, its operating advantages and specific objects
attained by its use, reference should be had to the accompanying
drawings and descriptive matter in which there are illustrated and
described preferred embodiments of the invention .
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a longitudinal sectional view through a mixing and
kneading device, taken along the line I--II of FIG. 2;
FIG. 2 is a cross-sectional view of the mixing and kneading
device;
FIG. 3 is a half cross-sectional view of another embodiment of the
kneading device shown in FIGS. 1 and 2;
FIG. 4 is a half cross-sectional view of still another embodiment
of the mixing and kneading device;
FIG. 5 is a developed view of an agitator element used in the
present invention;
FIG. FIG. 6 is another developed view of a different agitator
element for the present invention; and
FIG. 7 is a developed view of a third agitator element for use in
the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The basic concept of the present invention is illustrated in FIGS.
1 and 2. The mixing and kneading device includes a generally
horizontally arranged housing 1 with an agitator shaft 20 rotatably
mounted within the housing. At its opposite ends, the housing is
closed by walls 10, 15. The agitator shaft 20 is spaced radially
inwardly from the inner surface of the housing 1 and a plurality of
plate-like agitator elements 25 are fixed to the agitator shaft and
extend outwardly toward the housing in planes extending
substantially normally of the axis of the agitator shaft. As can be
noted in FIG. 1, a number of the planes of plate-like elements 25
are spaced axially apart along the length of the agitator shaft.
Further, in FIG. 2 it can be observed that in each plane, the
plate-like elements 25 are spaced circumferentially apart.
The housing 1 is provided with a heating jacket or heating duct 2.
For introducing the material to be processed into the housing and
for venting vapors, one or a number of connecting pieces 3 are
provided on the top of the housing. When the mixing and kneading of
the material is completed, the product is withdrawn through lower
connecting piece 4. Members 5 support the housing in stationary
positions.
End wall 10 of the housing is provided with a stuffing box 13 and a
cage 11 extends outwardly from the end wall and supports a bearing
12 for the agitator shaft end 21. At the opposite end of the
housing, end wall 15 has a stuffing box 18 and a cage 16 extends
outwardly from the end wall and supports a bearing 17 for the
opposite agitator shaft end 22. The ends 21 and 22 of the shaft 20
provide support so that it can be rotated within the housing by a
driving motor, not shown, via a V-belt pulley 23 and a slip-on
transmission 24.
As shown in FIGS. 1 and 2, an agitator arm or stirrer blade 26 is
secured to the radially outer edge of each of the plate-like
elements 25. In FIG. 2 the radially outer surface of the stirrer
blade 26 is coincident with the radially outer edge of the
plate-like element and both are spaced very closely from the inner
surface of the housing 1. Further, the plate-like element 25 is
relatively narrow in the axial direction of the shaft 20 while the
stirrer blades 26 extend axially from both sides of the blade-like
elements.
The agitator shaft 20 and the elements 25 can, as a rule, be heated
or cooled with the input of the heating or cooling medium through
connecting piece 29 and with the return of the medium taking place
through the connecting piece 30.
Because of their position relative to the inner surface of the
housing 1, the stirrer blades 26 can effect a scraping or cleaning
action along the inner surface. While the plate-like elements 25
located intermediate the ends of the housing have the stirrer
blades 26 extending from each of their axially facing sides, the
plate-like members located adjacent the end walls of the housing
have agitator arms or stirrer blades 27, 28 which project only
inwardly from the plate-like elements toward the opposite end of
the housing. The plate-like elements associated with the agitator
arms or stirrer blades 27, 28 provide a cleaning or scraping action
on the end wall of the housing while the stirrer blades 27, 28
clean the surface of the housing adjacent the end walls.
From FIG. 1 it can be noticed that the adjacent ends of stirrer
blades 26 extending from the plate-like elements 25 in planes on
the agitator are spaced apart to provide a slot 31. In the area or
axial extent of the slot 31 the stirrer arms 26 do not pass over
the inner surface of the housing. In the open space provided by the
slots 31 sturdy mounting supports 32 are secured to the inner
surface of the housing and extend radially inwardly for a distance
at least slightly greater than the dimension between the inner
surface of the housing and the radially inwardly facing surface of
the stirrer blades 26. The mounting supports 32 form part of
stationary counter elements and the radially inner part of the
counter elements consists of a counter blade, as shown in FIG. 2,
made up of an axially arranged kneader arm 35, a pair of arms 36
extending radially inwardly from the opposite ends of the kneader
arm, and an axially extending scraper 37 extending between the
radially inner ends of the arms 36. The edges of the arms 36 are
closely spaced from the adjacent surfaces of the plate-like
elements 25 and the scraper 37 is similarly closely spaced from the
surface of the agitator shaft 20 so that they provide a cleaning or
scraping action as the plate-like elements and stirrer blades
rotate past them. In a preferred embodiment, the counter-elements
as shown in FIGS. 1, 2, 3 and 4, are mounted on covers or panels 6
which can be removed from the housing to gain access to the
interior of the device so that it can be cleaned.
To provide a more complete picture of the counter blades, a portion
of FIG. 1 is shown cut away revealing the counter blades as having
a frame-like construction. In other words, the kneader arm 35 and
scraper 37 form axially extending members of the frame while the
arms 36 define its radial members with these parts defining the
openings through the counter blades.
When the agitator shaft 20 is rotated, the material within the
housing is rotated by frictional contact with the plate-like
elements 25 or by the blade effect of the agitator arms or the
stirrer blades 26. During this procedure, the agitating and mixing
of the material is substantially increased by the counter-elements.
This is especially true in the case of pasty materials, where the
mass of material is forced by the stirrer blades 26 through the
space between the inner wall of the housing 1 and the kneader arm
on the counter-element and is subjected to an intense shearing and
kneading effect. The arms 36 and the scrapers 37 which form the
blade or counter-blade portion of the counter-elements also serve,
as mentioned above, to provide a continuous cleaning action of the
heatable or coolable surfaces of the agitator shaft 20 and of the
axially facing surfaces of the plate-like elements mounted on the
shaft. Furthermore, the counter-elements are also designed to
contribute substantially to the kneading effect. In FIG. 3 the arms
36 have a curved or bent arrangement extending oppositely to the
direction in which the agitator shaft 20 rotates. This arrangement
of the counter-blades serves to direct the material from the
agitator shaft upwardly into the space between the housing and the
kneader arm 35.
In FIGS. 1 and 2 a single axially extending row of counter-elements
is shown, however, it is also possible to arrange two or more rows
of such counter-elements. In such a case, the counter-blades which,
viewed in the direction of rotation of the agitator, are mounted in
series on the housing, can be of different designs. For instance,
one of the counter-blades can, viewed from the holding support, be
arranged so that it only extends in the axial direction from one
side of the mounting support 32. Similarly, the next counterblade
can be arranged so that it extends from its mounting support in the
opposite direction. That is, as viewed in the drawings, one
counter-blade would extend to the left and the next counter-blade
would extend to the right. With regard to the shape of the
counter-blade there are many possible variations. As illustrated in
the drawings, the counter-blade can be provided with a frame-like
configuration or with a large areal surface. Frequently, as a
result of the appropriate shape of the kneader arm 35 in
combination with the shape of the stirrer blade 26, the kneading
effect can be improved, for instance, through the formation of a
conically-shaped space between the two kneading parts.
There are many possible variations in the arrangement of the
plate-like elements on the agitator and the stirrer blades
positioned on the elements. In addition to the selected number of
plate-like elements used, and their dimension and shape, one
particular arrangement, as illustrated in FIG. 4, is important. As
compared to the plate-like element 25 in FIGS. 2 and 3, in FIG. 4
the radially outer edge of the plate-like elements 39 are not as
close to the inner surface of the housing so that the stirrer blade
36 projects outwardly from the radially outer edge of the element
39, that is, the radially outer edge of the element 39 is spaced
from the inner surface of the housing by the radial dimension of
the stirrer blade 26 and the clearance between the stirrer blade
and the housing. In this arrangement the radially extending arms 36
of the counter-blade provides the cleaning action for the entire
radial extent of the element 39 as differentiated from the
arrangement shown in FIGS. 2 and 3.
FIGS. 5, 6 and 7 illustrate some of the many possible arrangements
of the agitator elements and the counter-elements. In these figures
the cylindrical housing 1 is developed or rolled out into a flat
plane. Accordingly, the agitator or plate-like elements 25 have
their contour projected onto the plane of the housing. In FIG. 5
one-half of the device is illustrated with all of the disk elements
being arranged perpendicularly to the axis of the agitator shaft 20
and with the stirrer arms 26 arranged not axially but at an angle
to the axial direction of the shaft. If the elements 25 move in the
direction of the arrow, this angular position of the stirrer blades
represented by reference numeral 40 causes a movement of the
material being processed toward the center of the device. In this
arrangement the counter-blades 41 of the counter-elements are
arranged in the axial direction of the shaft. Further, the elements
25 and their stirrer blades 27, 28 located at the opposite ends of
the housing provide a scraping or cleaning action with their edges
42, 43 of the end walls 10, 15 and in addition, their half stirrer
blades are arranged to direct the material toward the center of the
device.
A more preferred embodiment of the arrangement of the plate-like
elements and the counter-elements is shown in FIG. 6 where the
stirrer blades are not arranged exactly along the axial direction
of the shaft but are arranged along a line corresponding to the
transportation angle 40 of the stirrer blades. In other words, as
compared to FIG. 5, the stirrer blades are in alignment rather than
being in a staggered arrangement. This arrangement provides the
advantage that the conveyance of the material being processed from
one stirrer blade is not obstructed by the projecting edge of the
next blade. In this arrangement the counter-blades 44 or at least
their kneader arms are also positioned at an angle to the axial
direction of the shaft and housing with the angle being arranged
counter to that of the angle 40 of the stirrer blades. This
scissor-like arrangement is capable of increasing the kneading
effect within the device.
There is the drawback in the arrangements of FIGS. 5 and 6 in that
the passage of the stirrer blades through the kneading slots
between the housing and the kneader blades of the counter-blades
always occurs at the same time. As a result there are intense
surges of power required by the device each time stirrer blades
pass through the kneading slot, that is, three times during each
complete cycle of rotation of the agitator shaft. To overcome this
disadvantage, FIG. 7 shows a staggered arrangement affording a
better power distribution. In FIG. 7, the stirrer blades 51 are
arranged on the plate-like elements 50 so that only one of the
blades 51 passes through the kneading slot at a given movement
during rotation of the agitator shaft. The same purpose is likewise
served by the displacement of the plate-like elements on the
righthand side of the center line with respect to the plate-like
elements on the left by a certain peripheral angle.
All of the figures and embodiments described illustrate a device
for operation in a batch-type process, in which, under normal
conditions, the material is conveyed from the end walls toward the
center as it is rotated and then moves back again toward the end
walls. The principle underlying this mode of operation can,
however, be implemented as a continuously operating machine if all
agitator arms or stirrer blades, or at least the major portion of
them, have their angles set in such a way that the material is
conveyed from its input at one end of the device to its output at
the other end.
The particular advantage of the machine, that is, that the major
portion of the surfaces contacted by the material is cleaned
continuously, is of significance regarding the heating and cooling
of the processed materials, since, on one hand, the heat transfer
coefficient is improved and, on the other, build up of material on
the heating or cooling surfaces is avoided. The heating and cooling
of the surfaces can be performed in a known manner.
Occasionally, buildup or incrustation may develop which is
extraordinarily stubborn and, even though there is a very narrow
clearance between the surfaces to be cleaned and the members doing
the cleaning, it is extremely difficult to remove. However, it has
been found that such incrustations can be removed if the agitator
or housing, that is one of the cooperating members, is allowed to
vibrate with an amplitude of about half the clearance between the
member being cleaned and the one doing the cleaning, in view of the
fact that the vibration impacts effectively remove the
incrustation.
While specific embodiments of the invention have been shown and
described in detail to illustrate the application of the inventive
principles, it will be understood that the invention may be
embodied otherwise without departing from such principles.
* * * * *