US2295361A - Single rotor mixer for plastic material - Google Patents

Description

Sept. 3, 1942- c. F. scHNucK 2,295,361 A SINGLE ROTOR MIXER FOR PLASTIC MATERIAL Filed Oct. 24, 1959 4 Sheets-Sheet 1 p 8, 1942- c. F. SCHNUCK 2,295,361

SINGLE 'ROTOR MIXER FOR PLASTIC MATERIAL Filed 001:. 24, 1939 4 Sheets-Sheet 2 gyzvzv o v Sept. 8, 1942. a. F. SCHNUCK SINGLE ROTOR MIXER FOR PLASTIC MATERIAL Filed on. 24, 19 59 4 Sheets-Sheet 5 Sept. 8, 1942. c. F. scHNucK 7 SINGLE ROTOR MIXER FOR PLASTIC MATERIAL 4 Sheets-Sheet 4 Filed Oct. 24, 1959 0 31M v. 1 f

Patented Sept. '8, 1942 UNITED STATES PATENT orrlca SINGLE ltofriilig g- FOR PLASTIC I '1 Carl F. Schnuck, New Haven, Conn, assignor to Application October 24, 1939, Serial N6. 301,004

6 Claims.

This invention relates to a machine for mixing and kneading plastic material, and more particularly to a machine for mixing rubber, for example, and compounding it with various inredients.

In processing rubber crude rubber is masticated or kneaded into a plastic mass and usually at the same time is mixed with various ingredients added to the mass of rubber, such as reinforcing pigments, softeners, fillers and vulcanizing agents. It is very essential that the mixing operation be complete so that a thorough dispersion of the various ingredients through the mass of rubber is'obtained and a homogeneous product is secured. This is very essential to the uniformity of the product obtained by the mixing operation.

The present invention relates to a device for performing the mixing and kneading operations in a chamber of cylindrical shape, the chamber having an internally projecting rib atthe intermediate portion thereof extending generally circumferentially of the chamber over a considerable portion of the circumference. There is provided within the chamber a single rotorhaving thereon a set of blades at each end, these blades being helically arranged so as to work the material toward the center of the chamber from each end thereof past the intermediate rib.

In the past, devices of this general character have been made for this purpose but in many of such devices it has been found that while the mixing action at the center of the chamber adjacent the rib over which the material is extruded or forced by the blades, is very thorough and efficient, the same is not true of the action adjacent the chamber ends, so that one part of the mass may be more thoroughly mixed than another and as a result it was difllcult to secure a uniform, homogeneous product through which the various ingredients were thoroughly dispersed. In the present device this disadvantage has been overcome and a machine has been produced which not only brings about a thorough and effective mixing action so as to deliver a completely,

uniform product, but performs the mixing action in a relatively short time compared to the time required in the present machines, and also due to the arrangement and proportions of the device the mixing and kneading action may be carried on at a lower temperature than was previously the case.

These results are obtained in part by arrangin a single cylindrical chamber, as already described, of such proportions that its diameter is at least for commercial use the as great or greater than its length. so that the greater part of the action takes place adjacent the center of the chamber near the zone or the internally projecting rib. The diameter of the chamber being relatively large compared to its length also enables more effective cooling to be accomplished, as cooling passages may be provided substantially about the entire circumference of thechamberwhere the mixing action takes place.

One object of the present invention is the provision of a single rotor mixer for plastic material of improved and simple construction, which will bring about an effective and thorough mixing and mastication of the plastic material introduoed into the chamber of the machine.

A further object of the-invention is the provision of an improved mixing machine for plastic material having a chamber of cylindrical formation and a bladed rotor operating within the chamber, such that the greater part of the mix ing and kneading'action takes place'adjacent the central part of the chamber as opposed to the end portions thereof.

provision of a device of the character described provided with a cylindrical chamber having an internally projecting extrusion rib on its inner surface at substantially the central portion of the chamber and a bladed rotor operating within the chamber, the blades being'mounted in staggered relation upon each end of the rotor and extending helically to a point beyond thecenter thereof whereby the mass to be mixed will be rapidly moved toward the center of the chamber from the ends thereof and forced over the extrusion rib into the other'side of the chamber to produce a thorough mixing and masticating of the charge of material.

Tothese and other ends the invention consists in the novel features and combination ofparts to be hereinafter described and claimed.

In the accompanying drawings:

Fig. 1 is a front eievational view of a single rotor mixer embodying my invention, with the chamber and rotor being shown in section;-

Fig. 2 is a transverse sectional view on line 2-2 of. Fig. 1; a

Fig. 3 is a development view of the rotor as it would appear if flattened out;

Fig. 4 is an end elevation of the rotor, and

Figs. 5, 6 and 7 are front elevational views of the rotor showing it in progressive positions during its rotation.

To illustrate a preferred embodiment of my A still further object of the inventionis the the surface of 2 ,aos,se1

invention I have shown a mixer comprising a and to 7. the blades of the rotor extend to some base It, having end standards II and I2 rising extent beyond the center line thereof or beyond therefrom, which standards are provided with the intermediate extrusion rib 22, but are of less bearings l3 and H to rotatablysupport a rotor height adjacent their inner ends as will be hereshaft it upon which is secured a driving gear ll, 5 inafter explained, so as to leave some clearance driven by a pinion II, which may in turn be opposite the rib through which the material may actuated from any suitable source of power (not pass over into the other end of the chamber to shown). be caught, and operated upon, by the blades in Supported from the standards ii and II are that end.

end members It and II of annular formation, so Supported by the end members It and I! are a that the rotor may pass through the central pair of annular plates 36 and 31 which form the opening therein. Supported between these two end members of the chamber. Just below these plates is the chamber body 2| of cylindrical formembers are mounted rings 88 and 39, held in mation, this body being cored out to provide pas- I place by the supports 40 and H, which ringsilt sages II for a cooling fluid so that the temperais closely the openings within the plates It and ture may be regulated during the operation of 31. Secured in the end faces of the rotor are the device. It will, of course, be obvious that if annular members or rings 42 and 43, which bear it is desired to carry out a mixing operation untightly a ainst the rings 38 and 38 so as to close der a high temperature a heating mediuminstead the chamber ends about the rotor eiiectively and of a cooling medium may be introduced into the '20 prevent anv of the ingredients from beingforcedpassages II. "out of the chamber at this point.

Arranged circumferentially of the chamber It will be noted that the ends of the rotor fit body II at substantially the central portion closely against the plates 38 and 31 so as to obthereof is an inwardly projecting rib 22, shown viate as far as possible, the entrance of any of in transverse section in Fig. 1. The chamber is the material between the end of the rotor and provided with an upper charging opening 23 and these plates. Also, it will be noted from Figs. 8 a lower discharge opening 24, and from reference and 5 to 7,that the blades 84 are arranged at a to Fig. 2 it will be seen that the inwardly prorelatively large angle with respect to the rotor jecting rib 22 extends circumferentially about the axis so that as these blades attack the material inner surface of the chamber from one of these the tendency will be to drive it toward the central openings to the other. These openings, as shown portion of the chamber instead of around the pein Fig. 2, are located at one side of the vertical riphery'thereof, thus moving the material sharpcenter line of the chamber so that'the rib extends away from the ends of the chamber toward about a considerable'portion of the circumferthe intermediate rib and past this rib int the ence. It will also be noted that the rib is rela- 35. other end of the chamber.

. tively shallow as compared with the diameter of In Figs. 5, -8 and 7 of the drawings, the prothe chamber," and projects inwardly toward the gressive action .of the'rotor and blades thereon is axis of the chamber a-relatively shortdistance. shown. For example, in Fig. 5 one of the blades- The chamber may be charged through the hop- I4 lfas arrived at the point where its outer edge per 25 which leads into the charging opening 23 A is at the highest point of the circumference of and this opening may be closed by a plunger 2| the'chainber, audit will be noted that thetip oi during the operation oi: the machine. Likewise, the blade at this point works close to the inner the discharge opening 24 is' closed by a door memperiphery of the chamber wall. This is true of her flsecured to a sliding cylinder 28, which cyithe tip of the blade along itsentire length until inder is slidablymounted on supports 20 and 30 the intermediate extrusion rib is reached In carried by the base so that the door may be slid- Fig. 6 of the drawings, the rotor has progressed ably moved toward the left, as shown in Fig. 1; through a small angle of its rotation until the to permit the material to be discharged through central portion B of the blade 34 has reached the opening 24 after the mixing operation'iscomthe highest point of the chamber, and it will be Dleted. noted that the clearance of this-portion oi' the secured to the rotor shaft II is a winged or blade is substantially the same as shown between bladed rotor II, the body of which may be cored the point A thereof and the chamber wall in Fig.

- out to provide hollow interior passages 32 for the 5; As shown in Fig. 7 of the drawings, a further 'shown in Fig. 3, three of these blades 34 are ends of the rotor so that during the rotation of eption of a temperature-controlling fluid inrotation of the rotor has taken place until the troduced through the shaft Openings 33. in e e 1 of t g, u has amved at t Upon each end of the rotor are a number of blades which project from the body thereof toward the inner periphery of the chamber. As

substantially opposite the beeat 22, and that there l clearance between the wall as between the fgnd B. It will also be {the blade ll falls away point C, as shown at-D,

provided upon each end of the rotor,-making-six in all, although this number may be variedas desired. The blades at one end of the rotor are arranged in staggered relation with respect ta .those'of the other end, and-it will be notedthgt the blades are arranged helically on the surfaggg V of the rotor with the leading edge adjacent the V of the blad 39 th t-th the latter in the direction of the arrows in Figs. opening W l, 2 and 4, the charge of material within the into the "rich chamber will be moved from the end portions toshown in these) iii blade and the extrusion rib he chamber. It will be noted gxtends' beyond the rib clearance between thisn or extruded through the d end of .the chamber, as

ward the center thereof past-the rib 22 and forced The blades of the rotor areoi' substantially the over into the other end of the chamber between same formation and the action described .with' the wall thereof and the surface of the rotor in respect to one will be repeated each time the that end. charge is encountered and picked up by one of n will also be noted that as shown in Figs. 3 5; the blades. n will be apparent that,,due to the.

type comprising a casing of substantially cylindrical form providing a mixing chamber,-a gradually sloping rib projecting into said chamber at the middle portion thereof and constricting its diameter, and a rotor having a plurality of closely set, sharply pitched, but generally rounded blades in each end of the chamber to work the material over and pastsaid rib, said blades having their inner ends adjacent the rib but provided with substantial clearance with respect thereto, said rotor having in its face in the region adjacent the rib a tortuous rotorencircling valley or depression skirting the inner ends of said blades, and said blades making an angle of substantially 60 with the rotor axis to work the material in the tortuous path of said valley.

6. A rubber mixing machine of the enclosed type comprising a substantially cylindrical casing providing a mixing chamber, a gradually sloping rib extending into the chamber midway of its length, and a rotor for working the material in a tortuous path around the chamber and back and forth over the surface of said rib, said rotor having three blades in each end of the chamber in staggered relation to the bladesin the opposite end, said blades making an angle of substantially 60 with the rotor axis and each having rounded convex front and rear surfaces CARL F. 'scmwcx.

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