US 3860218 A
A pair of pressure cylinders are located in axial alignment, separated by a nozzle body through which at least one duct passes. Operating pistons move the composition of matter to be treated from one cylinder into the other, the composition being forced through the duct or ducts of the nozzle body. The ducts of the nozzle body have a cross section which is noncircular and may include a constriction so that flow through the duct or ducts will be at essentially uniform speed over its cross section to improve mixing and wall contact of individual elements of the substances passing through the duct or ducts. The nozzle body is clamped in position between the cylinders by a releasable compression element, for example, hydraulically operated; a release or lifting pressure jack is provided to separate the cylinders, when desired, so that the nozzle block can be easily removed.
Description (OCR text may contain errors)
United States Patent [191 Hiirlimann [451 Jan. 14,1975
 Inventor: Hans P. Hiirlimann, Hornlistrasse 60, Pfaffikon, Switzerland  Filed: Feb. 13, 1973  Appl. No.: 332,148
 Foreign Application Priority Data Feb. 18, 1972 Switzerland 2386/72  US. Cl. 259/98  Int. Cl B011 5/12  Field of Search 259/DIG. 30, 1 R, 98, 112, 259/185, 2, 4; 23/252 R Primary Examiner-Harvey C. l-lornsby Assistant ExaminerPhilip R. Coe Attorney, Agent, or FirmFlynn & Frishauf  ABSTRACT A pair of pressure cylinders are located in axial alignment, separated by a nozzle body through which at least one duct passes. Operating pistons move the composition of matter to be treated from one cylinder into the other, the composition being forced through the duct or ducts of the nozzle body. The ducts of the nozzle body have a cross section which is noncircular and may include a constriction so that flow through the duct or ducts will be at essentially uniform speed over its cross section to improve mixing and wall contact of individual elements of the substances passing through the duct or ducts. The nozzle body is clamped in position between the cylinders by a releasable compression element, for example, hydraulically operated; a release or lifting pressure jack is provided to separate the cylinders, when desired, so that the nozzle block can be easily removed.
19 Claims, 10 Drawing Figures PATENTEU JAN 1 41975 3.860.218 SHEET 30F 5 TREATMENT APPARATUS FOR COMPOSITIONS OF MATTER The present invention relates to an apparatus to treat compositions of matter, and more particularly to mix macro molecular substances.
Mixing apparatus and various types of treatment apparatus to treat macro molecular substances are known; one such apparatus utilizes a pair of essentially cylindrical compression cylinders which are separated by a nozzle block through which nozzle-shaped ducts pass. The treatment substance is included in the cylinders and pushed back and forth, through the apertures, to mix substances therein, or to treat substances by wall contact with the nozzle block.
In the specification and claims, the term treatment should be understood to mean a wide variety of operations and processes, and not only mixing. For example, other treatment processes may be plasticising, intermixing, adding and mixing, homogenizing, dispersing, separately or combined with further treatment operations such as addition of heat; removal of heat; extrusion through nozzles or constrictions; evaporation; vacuum treatment; or other treatment steps such as, for example, breakdown of macro molecular substances under increased pressure, for example gas pressure, linking, cross linking, or polymerization of substances, and other process and treatment steps.
Various types of apparatus have been proposed in order to treat compositions of matter in accordance with the one or the other desired treatment operation. Most such apparatus have specific advantages, but also specific disadvantages, so that various treatment steps can be carried out only partially, or by use of expensive or uneconomicalprocesses.
One type of well-known treatment apparatus is the so-called Banbury A pair of steel rollers, the temperature of which can be controlled, is located to form a slit or nip therebetween and substances to be mixed are pulled or drawn through the slit between the rollers. Depending on the width of the slit, and the difference in circumferential speed of the rollers, the substances being pulled through the slit are stretched, sheared, or mixed more or less. Proper use of the machine requires skilled and attentive operators. Additionally, the process is difficult to control and output which is not properly mixed is frequent; the output must, therefore, be constantly tested. In spite of these disadvantages, and in spite of the high labor cost for a unit of mixed output, the open mixing roller-type mill apparatus is widely used, primarily due to its versatility and adaptability to various substances.
Single-chamber enclosed mixers, of the Banbury or Werner & Pfleiderer type use a closed chamber, in which the substance to be mixed is included. A pair of shafts with eccentrically located projections or lands pass through the chamber, so that the goods to be mixed are placed under shear stress. This apparatus permits high shearing speed to occur only at localized regions and no assurance is given that all particles are subjected to passage through a zone of high shearing speeds during a plurality of times, as is required for homogenizing. Additionally, the substances to be mixed experience a temperature rise so that high shearing stresses cannot be obtained, necessary for dispersions, due to the decrease of viscosity. Cooling the chamber itself usually is not sufficient to remove generated heat,
since particularly macro molecular substances have a low heat conductivity. It is thus necessary to continuously peel off substance to be treated from the wall of the chamber. This peeling off of substance is carried out frequently only insufficiently. The chamber itself is subject to wear and tear and can be repaired, or serviced only in substantial intervals. In the meanwhile, the distance between a peeling apparatus and the wall of the chamber itself may become excessive. Increasing the temperature during treatment frequently is undesirable if components of the substance are heat sensitive; chemical reactions may result which may require that substance, which is not yet completely treated, must be removed from the enclosed mixer and immediately cooled, for example by intermediate cooling on a cooling mill or roller. The mixing chamber should be completely full. Treatment in which various elements or components should be treated in sequential steps is difficult to be carried out since the quantities to be mixed have to be matched to the required mixing quantities, at any time during the steps, which interferes with economical operation of the system and the treatment method. A fixed sequence of treatment steps has to be prepared although the mixing systems or types or steps should desirably be different. Thus, one type of mixing may be desirable for one type of substance since there may be deviations from ideal or design requirements. The mixer cannot accommodate such variations, and will not respond to control itself, or to be subject to external control, in case the specifically required mixing procedures should differ from batch to batch. Thus, the actual treatment of the material, and the resulting out put, may vary from batch to batch.
Rotary interior mixers have been proposed (see Swiss Pat. No. 505,678), in which a closed cylindrical chamber is provided within which a rotating and axially movable disk is placed. The disk separates the chamber into two sub-divisions. The apertured disk is rotated, and the substance to be treated is pressed from one portion of the chamber, towards the rotating disk, to pass axially through the apertures into the other chamber portion. Due to rotor rotation, the substance is subjected to shear stresses and plasticized thereby. Cooling of the rotor disk causes an increase in viscosityof the substance to be treated at the surface of the rotor, so that there will be steep temperature drops within the mass subjected to shearing stress, and the shearing process itself is changed from affecting warmer, and thus more viscous material. The material, interiorly, therefore is no longer heated at the surface of the disk only, which is the place at which high temperature gradients can be effectively compensated.
The rotor disk chamber mixer, such as the aforementioned chamber mixer can operate only in accordance with a fixed predetermined treatment sequence or system. Thus, the treatment itself may affect various batches differently, so that the actual composition of the substance to be treated may vary widely from batch to batch. It is, however, desired that the final output should be as uniform as possible, that the viscosity of the output should be uniform, and that the output substances be as consistent as possible so that they can be introduced into subsequent fully automatic treatment or working processes.
When the rotor disks of rotating disk-chamber mixers are to be replaced, supply and measuring lines for interior cooling or heating of the rotor have to be interrupted or broken, or sectionalized; comparison with apparatus which does not provide for heating or cooling of the rotor is hardly appropriate, since uncontrolled interior heating of the goods to be treated occurs, as in the shaft-type chamber mixers. The rotor disk thus must be cleaned from time to time, and certainly between batches, which leads to interruption in use and time-utilization, that is, efficiency of operation of the machine.
It is an object of the present invention to provide an apparatus to treat compositions of matter, in which disadvantages of the prior art are reduced to a negligible value or eliminated, and in which a wide variety of treatment steps can be carried out. The apparatus should, further, be capable of permitting automatic control of supervision and, when used for example for mixing, permit completely automatic control of the mixing processes or steps being carried out by the apparatus on the substances.
SUBJECT MATTER OF THE PRESENT INVENTION Briefly, a nozzle block, formed with at least one and preferably a plurality of parallel ducts is clamped between a pair of pressure cylinders, between which substances are pushed from one side of the block, through the block to the other. The cross section of the connecting duct, or ducts is selected, in accordance with the present invention, to be non-circular.
The nozzle block can readily be removed from its clamped position between the pressure cylinders and easily replaced. The connecting nozzles or ducts, between the pressure cylinders, can thus be designed to fit the desired process, and can be easily formed with necessary connections for cooling, heating, for the addition of test or sensing elements, and can be placed to be externally freely accessible. Thus, the substance to be treated can be directly affected by treatment parameters. The substance is immediately affected by these treatment parameters, which can be changed, and the entire substance is necessarily subjected to the treatment conditions which occur in the duct, or ducts in which it is treated. Thus, one single batch, by being moved repetitively to and fro between the treatment cylinders, through the duct or ducts, can be treated in various ways, with treatment being repeated until, upon measuring or testing, that degree of change in substance, due to treatment, is sensed, which is desired. Temperature, as well as uniformity of substance, viscosity and the like can be selected as test parameters, for which the substance is then checked.
The invention will be described by way of example with reference to the accompanying drawings, wherein:
FIG. 1 is a longitudinal sectional view, with the section lines being at 90 with respect to each other along lines I-I of FIG. la, in highly schematic representation, of the apparatus of the present invention;
FIG. la is a highly schematic top view of the apparatus of FIG. 1, and illustrating the apparatus of FIG. 1 omitting parts not necessary for an understanding of g the sectional view;
FIG. 2 illustrates conditions without addition, or removal of heat;
FIG. 3 with heat removal,.and FIG. 4 with addition of heat;
FIG. 5 is an isometric view, highly schematic of flow paths in an elliptical connecting duct;
FIG. 6 is a transverse view showing, from the top, flow conditions in an elliptical duct;
FIG. 7 is a perspective, exploded illustration of a nozzle block with a radially adjustable projecting element;
FIG. 7a is a top view of the nozzle block and its aperture, in schematic representation; and illustrating two projecting elements; and
FIG. 8 is a perspective, exploded view of nozzle blocks, partly broken away, in which the ducts have constrictions formed therein, and the nozzle blocks are assembled in sections.
Referring first to FIGS. 1 and la: A pair of pressure chambers 2, 3 are separated from each other by a nozzle block 1 which is axially pierced by one or more connecting channels or ducts 4. The pressure chambers 2, 3 are defined by cylinders 5,5 in which pistons 8, 8', respectively, are movably located. Each piston is connected to a piston rod 9, 9', respectively, operated by a hydraulic, pneumatic or other power system 7, 7 for example cylinders l1, 11' within which pistons l0, 10' are reciprocated under hydraulic pressure from supplies, not shown. A pair of hydraulic clamping pressure-cylinder arrangements 13, 13' (FIG. 1a) are located diametrically with respect to the apparatus at the upper side thereof; only one is visible in FIG. 1. The piston-cylinder combination 13 includes a piston rod 14 which acts over an elastic intermediate layer 18 on a pressure plate 17, to which the upper cylinder 5 is secured. Intermediate elastic counter plates 19 support cylinder 14a against a top yoke 20. The upper pressure cylinder can be lifted or raised by means of a separately releasable pressure cylinder-piston arrangement 21, 21 to permit easy removal of the nozzle block 1 after pressure has been released in the cylinder-piston arrangement l3, 13'.
The lower pressure cylinder 5' bears by means of flanges 22 on a frame 23. Frame 23 extends over the entire length of the apparatus and accepts longitudinal forces. Frame 23 and flange 22 bear against a support base 24, for example a concrete slab.
All cylinder-piston drives are operated by hydraulic pressure fluid, supplied from a pressure pump, not shown, over lines likewise not shown and well known in the art.
The nozzle block 1, located between the two pressure chambers 2, 3, has at least one connecting duct 4 therein, which has a cross section which is non-circular Mixing effects vary widely across the cross-sectional area of the ducts, particularly when the ducts are longer. Referring to FIGS. 24, which illustrate speed diagrams: Dilatant liquids, such as clay suspensions, slips, and the like have a shear speed which is roughly uniform throughout the entire cross-sectional area of the duct, as illustrated by the triangular speed profile shown under a in FIG. 2. If the liquid follows Newton law, such as water, or oil, then the shear speed drops about linearly from the wall of the duct towards the axis of the duct. At duct axis the shear speed is zero, as illustrated by the parabolic velocity distribution profile seen under b in FIG. 2. Liquids which are structurally viscous, or are non-Newton types, have a drop of shear velocity with respect to the axis of the duct, starting from the duct wall, which is even greater. Within a core zone, the shear or mixing effect is very low, as seen by the speed profile c in FIG. 2. The low mixing effect, particularly in liquids which are structurally viscous, can be improved by cooling the connecting ducts (see FIG. 3). The fact that the viscosity at the wall of the duct is much less, in high shear velocities, than in the center of the duct, with low shear velocity, can be compensated by dropping the temperature. By lowering the temperature, structurally viscous particles to be mixed have their viscosity increased, so that substantial cooling of the duct walls provides for a radial temperature gradient in the substance to be mixed, which counteracts the decrease in viscosity at the zone adjacent the wall. Cooling can be controlled in such a manner that practically the entire cross-sectional area of the duct will have even mixing effects see FIG. 3. Dilatant (graph a) and Newton-type (graph b) liquids will have increasing shear velocities, towards the direction of the axis of the duct, if the walls are cooled. In contrast, the non-Newton-type liquids (graph 0) have the desired triangular velocity profile.
Heating of the wall changes the velocity profiles, as seen in FIG. 4; the zone of decreased shear velocity is increased in all three liquids. The temperature dependence of viscosity is, however, not universally applicable with respect to many types of mixtures.
If the cross-sectional aspect of the duct is changed to deviate from a circular cross section, for example by forming the cross section as an oval, or a different form, then secondary currents will be obtained. For example, if the duct 30 (FIGS. 5, 6) has an oval cross section with a ratio of axes y x of 1 2, then structurally viscous liquids will have secondary currents A-A'; B-B'; C-C; and D-D' arise, so that the substance to be treated will flow along the longer axis towards the interior, and outwardly along the shorter axis, resulting in four spiral eddy currents, or spiral turbular flow paths. The substance to be treated will thus be, alternately, in a zone 31 of high shear velocity, that is, along the edge of the wall, and in a zone with low shear velocity in the region 32 of the flow along the core. The nozzle block 1 is constructed to have at least one duct of a cross section which is non-circular. For ease of manufacture and cleaning, the nozzle block may be made of a plurality of sections, as will be explained in detail in connection with FIG. 8.
The ratio of the short to long axes is not critical and may vary, for example between 1.5 l to 8 l. The length of the duct, with respect to the smallest diameter, may also vary in accordance with the articles to be treated. It has been found that a desirable range for some substances is a duct length of about times the dimension of the smallest diameter which may be selected to be between 0.5 and 3 mm, for example.
The flow paths illustrated in FIGS. 5 and 6 provide effective mixing of structurally viscous substances over the entire cross-sectional area of the duct, even without cooling of the duct walls.
The nozzle block of FIG. 7 is particularly designed to plasticize raw rubber. It utilizes pressure chambers 2, 3 and a nozzle of duct block 40 between the pressure chambers. The duct 41 in block 40 may be generally circular see FIG. 7a and the non-circular aspect of the duct is obtained by introducing obstacles within the clearance space of the duct, for example bolts 42.
Bolts 42 are pressed into the substance to be passed through the ducts, for example by a pressure drive illustrated by the double arrow 42', in such a manner that bolt 42 will cause interruption in straight flow through duct 41 to effect shear, and back-up or damming of the substance being pressed through duct 41. The bolt 42 can be moved from totally recessed position within block 40 to a substantially projected position. Increasing the extent of projection increases the plasticizing effect. The constriction may have a ratio of l 5 with respect to the clear diameter of duct 41. The constricton is preferably located in an intermediate zone constriction the connecting channel 41 and extends for an axial extent of no more than about the diameter of the duct 41.
Block 50, illustrated in FIG. 8, is a composite block which consists of section elements 52 set in a ring 51. It is particularly useful for a dispersion process, in which high shear stresses are to be obtained without temperature rise. Each one of the ducts has one or more inserts located therein to form a diaphragm-like constriction. The inserts are subject to wear, and are preferably made of hard metal. Very high shear stresses, and consequent heating of the substance will be caused by the inserts. The adjacent outer zones of the ducts 54 are constructed to remove the heat generated by the diaphragm-like constrictions 53 as much as possible; ducts 55 and 56 are located in the block to guide cooling fluid into the block; the blocks are formed with transverse bores 57 through which cooling fluid may pass. The sections 52 forming the block are separated along separating surfaces; the longitudinal ducts 54 are preferably located along the separating lines between the blocks, as seen in FIG. 8, so that the ducts may be freely accessible as open grooves formed in the separating surfaces of the elements.
The apparatus can be arranged in any orientation desired, vertically or horizontally. A chemically reactive gas, such as compressed air or other desired gases can be introduced into the reaction chambers 2, 3 in order to modify or affect the process, for example if raw or natural rubber is to be treated.
The machine is cleaned by removing the treated substance, for example by carrying piston 8 (FIG. 1) downwardly until it meets the nozzle block 4, that is, until it is flush with the forward edges of the cylinder 5. A solvent or other cleaning fluid is then introduced into the lower piston 5, for example by injection, and the solvent is then pushed back and forth between the two pistons 8, 8' until all remaining solid particles are dissolved; thereafter, the solvent can be removed by suction, ejected, or otherwise taken out of the chambers, by means not shown and well known in the art.
A vacuum pump can be applied to the pressure chambers 2, 3, for example by connection to a bore 25 formed in block 4, so that volatile components from the substance to be mixed can be removed; water, solvents, or other fluid can likewise be removed in this manner.
The nozzle block 4 is readily interchangeable, so that the particular nozzle block, with the particular size openings, and of the particular length which is most suitable for the substance to be treated can be selected. The interchange of nozzle blocks 4 is simple. One charge, or batch, in one of the cylinders can be treated in different ways by introducing different nozzle blocks so that sequential treatment by sequentially different processes, with sequentially exchanged nozzle blocks is possible. The temperature of the substance to be treated, for example to be mixed, can always be held below a critical value. The pressure chambers 2, 3 are easily cleaned by completely moving the pistons 8, 8 to their final positions. The amount of charge, or the size of the batch being treated can vary widely, within the capacity limits of the cylinders 5. This enhances the versatility of the equipment and permits adaptation to various types of treatment methods and programs, as desired, in any one installation. The apparatus can be operated automatically, and up and down (FIG. 1) movement of the pistons 8, 8', their speed, and the force can be controlled automatically for example based on sensing of the composition, or characteristics of the substances to be treated.
Various changes and modifications may be made within the inventive concept, and embodiments described in connection with any one of the drawings, and shown therein, may be adapted to other embodiments as desired.
1. Apparatus for treatment of composition of matter, particularly for mixing of macro molecular substances comprising:
a pair of opposed pressure cylinders (5, 5'), operating pistons (8, 8) therein and means (10, 11; 10', 11') moving the pistons in their cylinders;
a nozzle block (1; 40; 51, 52) located between the cylinders and being formed with at least one duct (4; 41; 54) of non-circular cross section establishing communication between said cylinders and to permit the composition of matter to be moved from one cylinder into the other, through the duct, upon movement of the pistons, to effect treatment of the composition of matter;
and quick-release pressure means comprising fluid cylinder and piston means (13, 13, 21) engaging at least one of said pressure cylinders to press said cylinders towards each other and releasably clamp the nozzle block between the pressure cylinders.
2. Apparatus according to claim 1, wherein the cross section of the duct is approximately elliptical and in which the ratio of maximum to minimum axis is about 1.5 1 to 8 l.
3. Apparatus according to claim 1, wherein the cross section of the duct forms maximum and minimum cross-sectional dimensions, and wherein the ratio of maximum to minimum cross-sectional dimension is about 1.5 1 to 8:1.
4. Apparatus according to claim 3, wherein the minimum dimension is between about 0.5 3 mm.
5. Apparatus according to claim 3, wherein the block has a dimension between terminal ends of the duct therethrough which is more than about ten times the minimum cross-sectional dimension of the duct.
6. Apparatus according to claim 1, wherein the duct is formed with a constriction located intermediate its length.
7. Apparatus according to claim 6, wherein the length of the constriction is in the order of the maximum cross-sectional dimension of the duct.
8. Apparatus according to claim 6, wherein the ratio of the cross-sectional area of the duct at the constriction with respect to the cross sectional area of the nonconstricted duct is about 1 5 or more.
9. Apparatus according to claim 1, wherein the nozzle (4, 54) is formed with inserts (53) projecting into the duct (54).
10. Apparatus according to claim 9, wherein the inserts projecting into the duct are of hard metal.
11. Apparatus according to claim 1, wherein the nozzle block comprises a plurality of elements (52) separable in parallel planes parallel to the axes of the duct on ducts and extending between the cylinders so that the duct or ducts are accessible as open grooves formed in the elements.
12. Apparatus according to claim 11, further comprising a carrier ring member (51) securing the elements together.
13. Apparatus according to claim 11, wherein the duct, or ducts (54) pass through the separating planes of the elements. I
14. Apparatus according to claim 1, further comprising a projecting bolt extending into the duct, the length of extension into the duct being adjustable.
15. Apparatus according to claim 1, wherein the fluid cylinder and piston means comprises compressing cyl inder piston means (13, 13) acting to press the pressure cylinders towards each other, and release cylinderpiston means (21, 21) selectively controllable, acting in opposition to the compression cylinder-piston means (13, 13) and located to relatively move the pressure cylinders (5, 5) in opposite directions with respect to each other, to release the nozzle block (1, 40, 51, 52) from clamped position between said cylinders (5, 5).
16. Apparatus according to claim 1, further comprising fluid duct means (25) formed in the nozzle block and externally accessible to permit introduction of treatment substance to the nozzle block, or the cylinders, respectively.
17. Apparatus for treatment of compositions of matter, particularly for mixing of macro molecular substances comprising a pair of opposed pressure cylinders (5, 5), operating pistons (8, 8) therein and means (10, ll; 10, 11') moving the pistons in their cylinders;
a nozzle block (1) located between the cylinders and being formed with at least one duct (4) to establish communication between said cylinders and to permit the composition of matter to be moved from one cylinder into the other, through the duct (4.) upon movement of the pistons, to effect treatment of the composition;
and releasable fluid cylinder piston pressure means (13, 13, 21, 21') acting on said opposed pressure cylinders (5, 5') clamping the nozzle block (1) between said cylinders while permitting quick separation of the cylinders (5, 5') to provide access to, and replacement of said nozzle block.
18. Apparatus according to claim 17, wherein the pressure cylinders (5, 5') are located vertically stacked above each other with the nozzle block (1) located between the pressure cylinders,
the cylinder-piston means includes fluid cylinderpiston compression means (13, 13') acting on the upper cylinder (5) of said vertically stacked pressure cylinders to clamp the nozzle block between said pressure cylinders, said cylinder-piston means further including release pressure-cylinder means (21, 21') acting on said upper cylinder (5) of said vertically stacked pressure cylinders to lift said upper pressure cylinder and release the nozzle on the other of said cylinders (5) to clamp the nozzle block (1) between said pressure cylinders, and further includes release piston-cylinder means (21, 21) acting on said other cylinder (5) to separate said compression cylinders from each other and release the nozzle block (1) from clamp engagement between said pressure cylinders.