A multi-shaft thin-layer reactor for treating fluid materials in which gaseous material is present during such treatment. The treatment involves the addition of gas to the fluid material or the removal of gas therefrom. The reactor includes a housing in which a plurality of axis-parallel conveying shafts are disposed. The housing is cylindrical and the shafts are disposed around the inner periphery thereof in such a manner that each shaft meshes with the two shafts adjacent thereto. The meshing shafts jointly define the outer periphery of a treatment chamber within the housing. At least one sun-and-planet roller extrusion assembly rotates the shafts and is adjacent at least one end of the shafts in a form-locking manner. The conveying shafts also scrape against the internal wall of the housing so that thin layers of the fluid materials fed into the reactor are formed and these thin layers become disposed on the conveyor shafts. Since the treatment chamber is connected to a vacuum source or to a source of gas, the material is readily gassed or degassed as desired. The material itself seals the treatment chamber.

The present invention relates to a multishaft thin-layer reactor. More 
particularly, the present invention relates to a multi-shaft thin-layer 
reactor for the continuous production of polymeric or other materials 
which are to be gassed or degassed. 
BACKGROUND OF THE INVENTION AND PRIOR ART DISCUSSION 
A reactor of this general type is disclosed in European Patent 
Specification No. 0 208 139A1. In such document, there is described a 
reactor comprising a housing within which is defined a chamber. The 
chamber is connected to a source of reduced or excess pressure depending 
upon whether the material is to be degassed or gassed. Within the chamber, 
a plurality of rotatably drivable, axis-parallel, intermeshing conveying 
shafts are mounted. The shafts are disposed around the interior periphery 
of the housing and each shaft meshes with the two shafts adjacent thereto. 
The shafts are all rotated in the same direction so that thin layers of 
the material to be treated are formed on the portions of the shafts which 
face into the chamber. Effectively, therefore the degassing or gassing 
chamber is formed radially inwardly of the conveying shafts. The shafts 
are not free to move axially but the longitudinal ends thereof are guided 
upwardly into a transmission unit so that they can be rotated. Such 
thin-layer reactor carries out an operation for degassing or gassing the 
material. Primarily, this prior specification is concerned with providing 
a system for sealing the conveying shafts. To effect gassing or degassing, 
the chamber, which is sealed at its upper and lower ends, is subjected 
either to an excess pressure or to reduced pressure, which latter may be a 
vacuum. 
The particular advantage of such an arrangement is that very thin layers of 
molten material are formed on the circumferential portions of the 
conveying shafts which face into the central degassing chamber. The 
chamber will, henceforth, be referred to as a degassing chamber although 
it will be readily apparent from the foregoing that it can equally act as 
a gassing chamber. The thickness of the layers of molten mass is dependent 
upon the spacing between the individual, intermeshing conveying shafts. 
The material to be treated which, in this instance, is in the form of a 
molten mass and is to be degassed, is fed into the reactor such that it 
passes onto the external surface of the intermeshing conveying shafts. Due 
to their rotation and to their surface geometry, the conveying shafts 
carry the molten mass into the central degassing chamber. In such chamber, 
the volatile components entrapped in the thin layers of molten mass are 
diffused onto the surface of the molten mass as a result of the reduced 
pressure being formed, and they are removed by suction. 
Due to the formation of these thin layers of molten mass, thin-layer 
reactors are particularly suitable for removing volatile components with 
the exception of a few parts per million thereof, from a molten mass or 
from a fluid. In particular, however, the parallel disposition of the 
intermeshing shafts ensures that all of the molten mass is spread to form 
thin layers and, in consequence, the volatile components can be removed 
therefrom in a highly satisfactory manner. 
However, in such thin-layer reactors, it has proved particularly difficult 
to seal the individual, intermeshing, conveyor shafts from the drive 
mechanism. This is essential if the pressure in the central degassing 
chamber is to remain as low as 10.sup.-4 bar. 
Complex sealing systems are required for this purpose and one such system 
is described in detail in the above-numbered European Patent 
Specification. Moreover, a complex transmission unit is required to rotate 
the intermeshing conveying shafts accurately and in the same direction. 
Such a transmission unit is disclosed in German Patent Specification No. 
30 30 541. 
Furthermore, in a thin-layer reactor of the above-described type, it is 
necessary to rotate the housing surrounding the conveying shafts in an 
oscillatory manner. This is to prevent layers of the material being 
processed from fritting or caking together on the internal wall of the 
housing. A system designed to achieve such oscillation is disclosed in 
German Patent Specification No. 35 13 536. 
OBJECTS OF THE INVENTION 
The present invention seeks to provide a thin-layer reactor of the 
above-described general type but in which complex sealing systems for the 
individual conveying shafts are no longer required and the means for 
driving the individual conveying shafts are substantially simplified. The 
present invention also seeks to provide a reactor in which it is 
unnecessary to rotate the housing in order to prevent material from caking 
on the internal wall of the housing. 
SUMMARY OF THE PRESENT INVENTION 
In accordance with the present invention, there is provided a multi-shaft 
thin-layer reactor for the treatment of fluid materials wherein gaseous 
components are present during said treatment, said reactor comprising 
housing means; said housing including a longitudinal axis; a wall surface 
spaced from said longitudinal axis to form an internal wall of said 
housing thereby defining a hollow interior within said housing and first 
and second opposed axial end regions; feed means for introducing said 
fluid material into said hollow interior of said housing; a plurality of 
conveying shaft means disposed adjacent one another within said hollow 
interior adjacent said internal wall; each said conveying shaft means 
including a longitudinal axis, said axes of said shafts all extending 
parallel with one another and each said shaft meshing with both said 
conveying shaft means adjacent thereto, all said conveying shaft means 
jointly defining the outer periphery of a chamber within said hollow 
interior of said housing; drive means operatively connected to each said 
conveying shaft means for rotation of each said shaft about its said axis; 
actuating means for actuating said drive means; and gas duct means in 
communication with said chamber for permitting selective inflow of gas 
into said chamber and outflow of gas from said chamber; wherein said drive 
means comprises at least one sun and planet roller extrusion assembly 
mounted in said housing in at least one of said opposed end regions and 
said operative connection between said drive means and each said conveying 
shaft comprises a form lock between each said shaft and respective ones of 
said planet rollers of said roller assembly whereby actuation of said 
drive means by said actuating means causes each said conveying shaft to 
rotate about its said axis with all said shafts being caused to rotate in 
the same direction as one another, said actuation further causing each 
said conveying shaft to scrape against said internal wall of said housing 
thereby causing thin layers of said fluid material to be formed on said 
outer periphery of said chamber. 
By providing at least one sun and planet roller extrusion assembly, any 
desired number of conveying shafts may be provided within the housing. Sun 
and planet roller systems are, of course, known per se and one such system 
is disclosed in German Offenlegungschrift No. 29 05 717. The conveying 
shafts are set in rotational motion about their own axes at a uniform 
circumferential speed whilst at the same time circulating around the 
longitudinal axis of the housing. During such circulation, the shafts 
scrape or brush against the internal wall of the housing. 
A highly complex system is generally required to seal the conveying shafts 
from a vacuum in known arrangements, even though the shafts in such 
arrangements merely rotate about their own axes. A considerable amount of 
both structural and material outlay is required to provide such systems as 
is clearly evidenced by the sealing system disclosed in European Patent 
Specification No. 0 208 139A1. 
The provision of at least one sun and planet roller extrusion assembly as 
is the case in the present invention solves all of the above-mentioned 
disadvantages in a very simple and economic manner. This is because only 
one shaft projects from the chamber defined within the housing, this being 
the shaft forming part of the actuating means which sets the sun and 
planet roller assembly rotating. Accordingly, the point of exit of this 
shaft from the housing is the sole point which requires the provision of a 
seal. 
Moreover, in a reactor according to the present invention, the need for a 
complex transmission unit to produce the rotation of the conveyor shafts 
is eliminated, without the operation of the thin-layer reactor being 
adversely affected in any way. In a very simple manner, the present 
invention ensures that all of the conveying shafts of the reactor are 
rotated about their own axes in absolute synchronism and uniformly. This 
is a consequence of the force-locking connection between the conveyor 
shafts and the set of planet rollers in at least one sun and planet roller 
extrusion assembly. 
In addition to their rotation about their own axes, the conveying shafts 
are also caused to travel around a circular path around the axis of the 
housing. In a preferred embodiment of the invention, each said sun and 
planet roller extrusion assembly comprises central spindle means said 
spindle means including an outer surface and teeth means formed on said 
outer surface, and a plurality of planet spindle means disposed around 
said central spindle at uniform inter-center spacings from one another, 
each said planet spindle including an outer surface and teeth means formed 
on said outer surface; and inwardly directed teeth means formed on said 
internal wall of said housing whereby said teeth means formed on said 
outer surface of said planet spindle means mesh with both said teeth means 
formed on said central spindle means and with said teeth means formed on 
said internal wall. 
The engagement of the teeth on the planet rollers with the teeth on the 
central spindle of the or each sun and planet roller assembly and also 
with the teeth provided on the internal wall of the housing ensures such 
travel. The internal wall of the housing is also cleaned because of the 
circular path of the planet rollers around the internal wall of the 
housing. In consequence, it is not necessary for the housing to be 
rotated, as is the case in the apparatus disclosed in German Patent 
Specification No. 35 13 536. Accordingly, a thin-layer reactor in 
accordance with the present invention can be manufactured in a 
substantially more economic manner than has hitherto been possible. 
Furthermore, the fluid material, while passing through the planet rollers 
of the sun and planet roller extrusion assemblies undergoes additional 
homogenization. This is due to a combination of the rolling action between 
the teeth on the planet rollers and the teeth on the internal wall of the 
housing, on the one hand, and between the teeth on the planet rollers and 
the teeth on the central spindle, on the other hand. The axial length of 
each of the planet roller extrusion portions to be used is selected in 
dependence upon the viscosity of the material being treated. If a chemical 
reaction takes place in the reactor, the axial length is selected in 
dependence upon the properties of the product being produced. 
If desired, the planet rollers may be provided only to effect a 
transmission function, without being required to produce any homogenizing 
effect. In such a case, the axial length of the planet rollers can be kept 
very short. 
In a preferred embodiment of the present invention, sun and planet roller 
extrusion assemblies are provided in both said opposed end regions of said 
housing and each assembly includes a central spindle, the reactor further 
comprising shaft means connecting said central spindles, said shaft 
extending longitudinally through said chamber and surrounding said central 
longitudinal axis of said housing, said central spindles and said 
longitudinally extending shaft jointly defining an internal bore 
surrounding said longitudinal axis of said housing, said reactor further 
including flange means communicating with said bore, and means for 
supplying gas to said bore and means for removing gas from said bore, 
selectively communicable with said flange means, said shaft additionally 
defining bore means extending transversely to said longitudinal axis, said 
transversely extending bore means communicating laterally with said 
chamber, and wherein said actuating means are disposed on one of said 
central spindles. 
In such an arrangement, it is desirable that said central spindles of both 
said sun and planet roller extrusion assemblies and said shaft connecting 
said central spindle are formed integrally with one another. 
The connection between the central spindles of the upper and lower sun and 
planet roller assemblies by means of a shaft having a reduced diameter 
compared with that of the central spindles is advantageous because the 
volume of the chamber formed between these two spindle portions and 
bounded by the conveying shafts is increased. The central spindle of the 
upper and lower planet roller extrusion portions and the shaft may be 
produced in one piece, so that both sets of planet rollers rotate 
absolutely synchronously with the conveyor shafts disposed therebetween. 
The drive means for effecting the rotational and circulatory movements of 
the conveyor shafts communicates with a shaft, which is connected to an 
upper centrally disposed spindle. 
With very large sized reactors, however, it may be advantageous, for 
example, to screw-connect both the upper and lower central spindle 
portions to a shaft. 
Further preferably, each said conveying shaft means has two axially opposed 
end regions at least one of which defines a longitudinally extending 
threaded internal bore, and said planet rollers in said assembly at said 
at least one end each carry bolt means extending axially therefrom, said 
bolts engaging each said threaded internal bore to produce said 
form-locking connection. 
A bore is provided centrally in an upper central spindle portion, which 
bore communicates with the bore formed in the shaft connecting the two 
central spindle portions of the sun and planet roller assemblies and 
selectively with either a vacuum source if the material is to be degassed 
or with a gas source if gas is to be introduced into the material. 
In a simpler embodiment, which can be manufactured more economically, the 
conveying shafts of the reactor are merely guided and are driven 
unilaterally by the planet rollers of a sun and planet roller extrusion 
assembly. In this embodiment, the free ends of the conveyor shafts are 
located in and guided by an annular recess formed in a connecting flange. 
In this embodiment, the conveyor shafts are mounted to rotate around a 
central, conically formed displacement member.

DESCRIPTION OF PREFERRED EMBODIMENTS 
In FIG. 1, there is shown a thin-layer reactor which comprises a reactor 
housing 5. Centrally disposed within the housing 5 is a longitudinally 
extending drive shaft 1. In the upper and lower end regions of the 
housing, upper and lower sun-and-planet roller extrusion assemblies 2 and 
3 respectively are disposed on the drive shaft The upper roller assembly 2 
comprises a central spindle 13 which is provided, on its external 
periphery, with teeth which are inclined with respect to the longitudinal 
axis of the spindle and with respect to a plurality of toothed planet 
rollers disposed on spindles 16. The lower roller assembly 3 is similar to 
the upper roller assembly 2 and comprises a central spindle 15 and planet 
rollers disposed on spindles 17. The two central spindles 13 and 15 are 
interconnected by means of a central shaft 14. An adjustment spring (not 
shown) is provided for adjusting the location of the roller assembly 2. 
The planet rollers mounted on the spindles 16 and 17 respectively mesh with 
one another and are disposed adjacent the internal periphery of the 
housing 5. A plurality of conveying shafts 4, also disposed within the 
reactor housing 5, are each screw-connected to a separate bolt (not 
shown), the bolts being shaped to fit onto each of the planet spindles 16 
and 17. The bolts are screw threaded. The conveying shafts 4 extend 
substantially parallel to the axis of the housing 5. The upper and lower 
sun and planet roller extrusion assemblies 2 and 3 and the conveying 
shafts 4 are therefore all disposed in the housing 5. Heating elements 6 
are provided around the external periphery of the housing 5, in order to 
permit the temperature of the molten material being treated within the 
housing to be modified. The conveying shafts 4 are provided with discs or 
flights which are so arranged that, when the shafts 4 rotate, the discs or 
flights provided on adjacent shafts 4 brush past one another. Effectively, 
therefore, a degassing chamber 19 is defined within the housing 5 radially 
inwardly of the shafts 4. 
A discharge screw portion 7, which is itself provided with conveyor 
flights, is mounted on the lower central spindle 15. This causes a 
build-up of a tool pressure which ensures that the degassing chamber 19 is 
sealed in a downward direction, in a vacuum-tight manner. 
The drive shaft 1 is mounted in an axial bearing 9 and sealed upwardly by 
means of a shaft seal 8. 
The molten material to be treated is fed into the reactor, under pressure, 
through a feed aperture 10 formed in a shoulder portion of the housing 5. 
An annular conduit 23 is disposed beneath the feed aperture 10 and is 
disposed substantially centrally above the line of separation between the 
upper planet rollers mounted on the spindles 16 and the internal wall 24 
of the housing in the region of the upper sun and of the planet roller 
extrusion assembly 2. This is advantageous because it provides 
substantially uniform distribution of the molten mass which has been 
introduced around the internal wall 24. Furthermore, the distribution of 
the molten mass can be further improved by providing a plurality of feed 
apertures 10, which would all be disposed above the annular conduit 23. By 
feeding the material under pressure into the reactor, the degassing 
chamber 19 is, effectively, sealed at its upper end. 
The shaft 1 is provided with a central axial bore 27. The bore 27 
communicates with means (not shown) for producing a vacuum. Such 
communication is achieved by the use of a connecting flange 12. 
Transversely extending bores 18 are also provided in the shaft 1, which 
bores 18 communicate with the axial longitudinal bore 27. This permits the 
production of a vacuum in the degassing chamber 19. 
The embodiment shown in FIG. 2 differs from that shown in FIG. 1 in that 
conveying shafts 4 are connected only at their upper ends to the planet 
roller spindles 16. At their lower ends, they extend freely into an 
annular recess 20, which is formed in a connecting flange 22 connected to 
the lower end of the housing 5. A substantially conical displacement 
member 21 is screwed into the lower end of the shaft 14. 
The mode of operation of such a thin-layer reactor will now be described. 
A molten mass of, for example, polyethylene to be degassed is fed through 
the feed aperture or apertures 10 into the annular conduit 23. It then 
passes through the gaps 25 formed between the internal wall 24 of the 
housing and the planet rollers mounted on the spindles and through the 
gaps 26 formed between the planet roller and the central spindle 13. 
Degassing chamber 19 is, as aforementioned, sealed at its upper end by the 
molten mass being introduced under pressure. 
The inclined toothed planet rollers mounted on the spindles 16 are caused 
to travel along the internal wall 24, which is also toothed, of the 
housing by setting the inclined toothed central spindle 13 in rotational 
motion. As can be seen in FIG. 4, planet spindles 16 simultaneously rotate 
about their own axes, as shown by the arrows 29 and simultaneously execute 
a circulatory movement, as shown by the arrows 30, around the central 
spindle 13. 
The molten material passes through the annular conduit 23 into the cavities 
25 shown in FIG. 3 and is thus conveyed downwardly onto the external 
surface of the conveying shafts 4 into the cavities 26, shown in FIG. 4 
formed between the discs or flights on the shafts 4 and the internal wall 
of the housing 5. 
A certain amount of molten material is entrained by the rotating conveying 
shafts 4 into the degassing chamber 19 and thin layers of molten mass are 
formed on the shafts 4. The thickness of the layers of molten mass 
deposited on the peripheral portions of the conveyor shafts 4, which 
effectively form the radially outer periphery of the degassing chamber 19, 
is determined by the spacing between the kneading discs or other elements 
or the flights of the conveying shafts 4. In consequence, it is always 
possible to adapt the thin-layer reactor of the invention to differing 
material viscosities simply by interchanging the conveying shafts 4 in use 
by shafts having a different geometry of flights, or kneading discs which 
may have larger or smaller spacings from one another. 
As is well-known, it is very difficult to remove volatile ingredients from 
a high-molecular weight, highly viscous molten mass. A rapid and economic 
degassing is only possible if extremely thin layers of material can be 
provided over a large surface area. In the present application, the large 
surface area is achieved because of the surface area of the discs or 
flights forming the periphery of the degassing chamber 19 is very large. 
The conveying effect is adjustable by suitably selecting the geometry of 
the conveying shafts 4. The molten material is conveyed downwardly by the 
shafts 4 and enters the lower sun and planet roller assembly 3. 
A high vacuum is produced in the degassing chamber 19 by means of a vacuum 
pump (not shown), which is connected to the degassing flange 12. The bore 
27 and the apertures 18 in the shaft 14 cause the vacuum thus produced to 
prevail in the chamber 19. 
The sealing effect at the lower end of the chamber 19 is achieved by means 
of the presence of the molten material in the discharge screw 7. The 
molten mass is discharged through the discharge opening 11 under pressure 
for any desired further treatment. It may, for example, be supplied to a 
water-ring granulator. 
The thin-layer reactor is preferably utilized for polymerization, addition 
polymerization and the condensation polymerization of plastics materials. 
In such reactions, any volatile components in the molten material 
generally must be removed. However, the thin-layer reactor of the present 
invention can obviously also be operated in a manner opposite to that 
described hereinbefore. Hence it is often expedient to blend a gas with 
fluid or liquid substances in order to carry out some chemical reactions. 
To achieve this, the gaseous substance is then passed into the degassing 
chamber 19 through the flange 12 instead of a vacuum being produced. 
Rotation of the conveying shafts 4 produces thin layers of the liquid or 
fluid which readily entrains the gaseous substance.