Abstract:
A homogenizing apparatus has a number of grinding units made up of rotatable grinding members mounted in sequence on a drive shaft and corresponding fixed grinding members connected in sequence and supported only by the support frame which rotatably supports the drive shaft. The grinding surface of each rotatable grinding member opposes the grinding surface of a corresponding fixed grinding member, thereby forming a number of grinding zones. The raw material to be ground passes through all of the grinding zones in sequence. Complex pairs of grinding members can be added or removed to achieve the desired degree of grinding.

Description:
FIELD OF THE INVENTION 
     This invention relates to an apparatus for continuously pulverizing solid powder of cosmetics, medicines, foods, chemical products, or the like for homogenization. 
     BACKGROUND OF THE INVENTION 
     It is generally known that an object material is passed through a grinding zone comprising a pair of grinding members arranged in opposition to each other to form a grinding unit, thereby pulverizing the material for homogenization. This grinding unit is arranged in a processing container such that one grinding member thereof is mounted fixedly on and rotated by a driving shaft rotatable in the container, and the other grinding member thereof is fixedly mounted also within the container, the grinding members having grinding surfaces which are in frictional engagement with any raw material therebetween. 
     In general, one grinding unit consisting of a pair of grinding members as mentioned above is provided in a processing container. 
     In the above-mentioned conventional type of homogenizer in which one grinding unit is provided in a container of predetermined dimensions, due to the limited dimensions of a processing container it is difficult to increase the number of grinding units for the purpose of improving the homogenization performance of the apparatus. In other words, it is difficult to adapt such a conventional homogenizer to a multi-stage homogenizing operation. 
     BRIEF SUMMARY OF THE INVENTION 
     An object of the present invention is to eliminate the disadvantages of a conventional homogenizer of this kind and, more specifically to provide a homogenizer in which the component members of a plurality of grinding units can be arranged to form a processing container, thereby eliminating the need for a separate container, whereby a multi-stage homogenizer can be constructed easily and advantageously therefrom. In accordance with the invention, the number of grinding units used to make up such a multi-stage homogenizer may be easily increased or decreased depending on the kind of material to be processed. Thus, the axial dimension of the container can be varied automatically in accordance with the number of grinding units used. The homogenizer of the present invention is characterized in that it comprises a suitable number of grinding units, each of which consists of a flange-like movable member having an annular grinding surface formed on one side thereof and a cylindrical fixed member having formed on one side thereof an annular grinding surface which is arranged to oppose the annular grinding surface of the movable member. The fixed and movable members are combined to form a grinding zone of the unit. On the other side of the fixed member, a cylindrical portion is provided which is larger in diameter than the annular grinding surface and which projects from the fixed member. The movable members are mounted on a portion of a drive shaft which projects beyond a fixed machine frame. The projecting portion is inserted sequentially through the movable members of the respective grinding units. The movable members are secured thereon such that respective spaces are formed between the grinding zones of the respective units. The fixed members of the respective units are connected to one another sequentially at their cylindrical portions. An end member having a raw material feed port is connected to one end grinding unit. An end member having a discharge port is connected to the other end grinding unit. The two end members and a suitable number of the cylindrical fixed members interposed therebetween combine to form a cylindrical container which houses therein the grinding zones of the respective units and the projecting portion of the drive shaft and which is fastened securely to the fixed machine frame. A raw material fed through the feed port by pressure passes through the grinding zones of the respective grinding units and exits after processing by way of the discharge port. 
     In a homogenizer according to the present invention, a suitable number of grinding units, each of which has a grinding zone formed by a movable member and a fixed member, are mounted on a driving shaft projecting from a fixed machine frame, by slidably fitting the movable members of the grinding units sequentially onto the driving shaft and securing them thereon. 
     The fixed members of the respective units and the end members connected to the first and the last grinding units in the apparatus combine to form a container, which container is fastened securely to the fixed machine frame, so that there is provided a multi-stage homogenizer having a desired number of grinding zones formed in the container and a raw material fed into the container from a feed port by pressure is moved to pass sequentially through the grinding zones of the respective grinding units now in a multi-stage arrangement, this raw material being homogenized more finely each time it passes through a grinding zone. 
     Therefore, according to the present invention, the fineness of the pulverization for the purpose of homogenization can be adjusted by increasing or decreasing the number of movable members mounted on the driving shaft projecting from the fixed machine frame, while the size of the container formed by the fixed members is automatically changed in accordance with the increased or decreased number of movable members. This arrangement prevents the container from becoming too large or small for the number of grinding units installed therein. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The preferred embodiment of the present invention will be described in detail with reference to the drawings, wherein: 
     FIG. 1 is a side elevation of the homogenizing apparatus according to the present invention; 
     FIG. 2 is an enlarged, sectioned side elevation of a principal portion of the homogenizing apparatus; 
     FIG. 3 is an enlarged, sectioned side elevation of a principal portion of the homogenizing apparatus with the number of grinding zones reduced; 
     FIG. 4 is a perspective view of a movable member; 
     FIG. 5 is a perspective view, which is taken from the opposite side with respect to FIG. 4, of the movable member; 
     FIG. 6 is a perspective view of a fixed member; and 
     FIG. 7 is a perspective view, which is taken from the opposite side with respect to FIG. 6, of the fixed member. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the drawings, reference numeral 1 denotes a fixed machine frame which supports a driving shaft 2. This driving shaft 2 is adapted to be rotated by a motor 3 via a transmission of, for example, a gear mechanism 4, and one end portion 2a of the driving shaft 2 projects a predetermined length beyond the machine frame 1. 
     Reference numeral 5 denotes a grinding unit consisting of a movable member 6 and a fixed member 7. As shown in FIGS. 4 and 5, the movable member 6 comprises a flange-like member having an annular, uneven rough grinding surface 6a on one side thereof. In the illustrated embodiment, a tubular portion 6b is formed integrally with the movable member 6 on the side thereof opposite to its grinding surface 6a. The tubular portion 6b receives the projecting portion 2a of the driving shaft 2 for fastening the movable member securely to said shaft. 
     As shown in FIGS. 6 and 7, the fixed member 7 comprises a flange-like member having on one side thereof an annular grinding surface 7a which is arranged to oppose the annular grinding surface 6a of the movable member 6 and combines therewith to form a grinding zone 5a. A cylindrical portion 7b, the diameter of which is larger than that of the annular grinding surface 7a, is formed on the other side of the flange-like member. In the illustrated embodiment, the fixed member 7 is provided with a flange 7c having connecting holes 7d for use in connecting a suitable number of fixed members 7 to one another in series as will be described later. 
     Reference numeral 8 denotes one end member, which is formed to be a cylindrical body having a flange 8a at one end thereof, a discharge port 11 being formed in the cylindrical portion of end member 8. 
     Reference numeral 9 denotes the other end member, which is formed like a disc in which an axial raw material feed port 10 is provided. An annular grinding surface 7a&#39; is formed on the inner side of the end member 9. 
     In the illustrated embodiment, there are three grinding units 5, each consisting of a movable member 6 and a fixed member 7, the movable members being mounted on the projecting portion 2a of the driving shaft 2 projecting beyond the fixed machine frame 1 as shown in FIG. 3. However, in accordance with the invention fewer than three units can be incorporated in the homogenizer. 
     More than three grinding units may be incorporated depending on the length of the projecting portion 2a of the driving shaft 2. The mounting of the grinding units 5 on the projecting portion 2a of the driving shaft 2 is carried out as follows. As shown in FIG. 2, first, the cylindrical end member 8 is fixed at its flange 8a to the outer end surface of the fixed machine frame 1 and a suitable number of connecting rods 12 are screwed at their base end portions to be fixed to the flange 8a of the end member 8 so as to project in the forward direction. Next, the tubular portion 6b of the movable member 6 of the first grinding unit 5 is then slidably fitted onto the projecting shaft 2a, and the connecting rods 12 are inserted into the connecting holes 7d provided in the flange 7c of the fixed member 7 of the same grinding unit 5. As a result the fixed member 7 is connected to the front portion of the end member 8 and the annular grinding surface 7a of the fixed member 7 of the first grinding unit is positioned to face the annular grinding surface 6a of the corresponding movable member 6, thereby forming a grinding zone 5a therebetween. 
     The movable members 6 and fixed members 7 of the second and third grinding units 5 are then mounted in series in the aforementioned manner on the projecting portion 2a of driving shaft 2 and on the connecting rods 12 respectively to form the second and third grinding zones 5a. Finally, the movable members 6 of the respective grinding units 5 are tightened together by a nut 13 threadingly engaged with the free end of the projecting portion 2a, so as to fasten the movable members 6 to the driving shaft 2, and the end member 9 is then mounted on the connecting rods 12 by having the rods inserted therethrough so as to securely abut the fixed member 7 of the final grinding unit. The nuts 12a are then tightened to secure the two end members 8,9 and the fixed members 7 interposed therebetween in series so that there is formed by this interconnection a cylindrical container enclosing the three grinding zones 5a and the projecting portion 2a of the shaft 2 therein. In this container, the grinding zones 5a of the grinding units are suitably spaced from one another by the tubular portions 6b of the movable members 6 and the cylindrical portions 7b of the fixed members 7 of the grinding units, while spaces are also formed on both sides of each grinding zone 5a. 
     In the illustrated embodiment, a fourth grinding zone 5a&#39; is provided additionally after the third grinding zone, forming a space therebetween by utilizing the end member 9. This fourth grinding zone 5a&#39; is formed by firmly fitting a movable member 6, the shape of which is identical with that of the movable members 6 mentioned above, around the projecting portion 2a of the driving shaft 2 which is immediately beyond the third grinding unit 5, in such a manner that an annular grinding surface 7a&#39; formed on the inner side of the end member 9 faces an annular grinding surface 6a which is formed on the fourth movable member 6. The fourth movable member is adapted to be turned such that its annular grinding surface and grinding surface 7a&#39; frictionally engage any raw material therebetween. 
     A raw material to be processed is sent under pressure through the feed port 10, passes in sequence through the above-described four grinding zones (5a&#39;, 5a) and exists through the discharge port. The raw material is pulverized by the frictional movements of the grinding surfaces of the movable members, which are rotated by the driving shaft 2, with respect to the grinding surfaces of the fixed members in the grinding zones. 
     In this embodiment, the direction in which the raw material flows may be reversed by making port 11 the feed port and making port 10 the discharge port. 
     The clearance between the annular grinding surfaces 6a, 7a which forms each grinding zone 5a can be adjusted by changing the thickness of a washer 14 inserted between the movable member 6 of the first grinding unit and a stepped portion 2b formed on the driving shaft 2. The movable members 6 of the grinding units are connected sequentially by knock pins 15. The fixed machine frame 1, end members 8,9 and fixed members 7 are connected in an airtight manner by inserting packings 16 between the joint portions thereof. 
     If it becomes necessary to decrease the fineness of the pulverization performed by a homogenizing apparatus (that is, increase the particle size) in which three grinding units 5 are incorporated as mentioned above, the third grinding unit 5 is removed, and the end member 9 is moved axially inwardly, thereby reducing the number of grinding zones from four to three as shown in FIG. 3. In the alternative, the second grinding unit 5 can also be removed, thereby reducing the number of grinding zones from three to two, whereby the degree of coarseness is further increased. In such a case, a sleeve 17 of a predetermined length is fitted around the portion of the projecting portion 2a of shaft 2 which is beyond the movable member 6 in the end position, and it is secured by a tightened nut 13. In a homogenizing apparatus having a reduced number of grinding zones 5a, the number of grinding units 5 can be increased as occasion demands. When the grinding zones are thus increased and decreased, the number of fixed members 7 in use increases and decreases accordingly, so that the axial dimension of the container formed by the end members and fixed members varies automatically in accordance with the number of grinding zones 5a. Further, the grinding zones 5a may have the annular grinding surfaces 6a, 7a whose surface serrations are closer and finer as they are located closer to the discharge port side so that the grinding fineness may be increased. It is also possible that there may be interposed space of predetermined thickness between the adjacent movable members 6, 6 so that a space between the annular grinding surfaces 6a, 7a may be freely adjusted. 
     This embodiment is so formed that in addition to the grinding operations, the annular grinding surfaces 6a, 7a of the movable and fixed members 6, 7 perform the raw material-shearing and agitating operations. A cylindrical portion is provided on the surface of both the movable member 6 and the fixed member 7 in each grinding unit on the side opposite to the side carrying the grinding surface, and a plurality of axially extending slits are provided in the circumferential wall of each of the cylindrical portions of members 6, 7 to thereby form a plurality of cylindrically arranged comb-like projections 6c, 7e. These cylindrical portions of the movable and fixed members 6, 7 have different diameters so that projections 6c, 7e can be readily overlapped one over another. Upon assembly, the projections 7e of the fixed member 7 in the first grinding unit are encircled by the projections 6c of the movable member 6 in the second grinding unit and the projections 7e of the fixed member 7 in the second grinding unit are encircled by the projections 6c  of the movable member 6 in the third grinding unit. The material-shearing and agitating operations are carried out by rotating the movable members 6, whereby the projections 6c rotate about the axis of the shaft 2. 
     The present invention enables a plurality of grinding zones to be easily formed in a multistepped manner by mounting a plurality of grinding units on a driving shaft in such a manner that the grinding units can be freely mounted or detached in the axial direction of the driving shaft. In each grinding unit the grinding surface of a movable member is rotated to frictionally engage any raw material sandwiched between the grinding surface of the movable member and an opposing grinding surface on a fixed member, these opposing grinding surfaces forming a grinding zone. Since a suitable number of fixed members, which are cylindrically formed, are arranged in contact with each other between two end members and are coupled in series, the multistep grinding zones as well as an enclosing container are formed at the same time. Moreover, the number of fixed numbers in use can be increased or decreased in accordance with an increase or decrease in the number of required grinding zones, so that the axial dimension of the container can be varied automatically. Accordingly, the required number of grinding zones can be selectively provided, and a raw material can be processed in a container having a reasonable axial dimension, the desired coarseness of the processed material being attained during the selected number of grinding steps. Therefore, the disadvantages of a conventional homogenizing apparatus of this kind, in which the formation of multistep grinding zones and the selection of the number of grinding units to be used are difficult since a grinding unit in such an apparatus is installed in a prefabricated container or vessel, can be eliminated. Thus, according to the present invention, a conveniently usable homogenizing apparatus can be obtained.