US2584525A - Mixing machine - Google Patents

Description

Feb. 5, 1952 1. M. E. AITKEN MIXING MACHINE Filed Sept. 4, 1947 f l l a I F/Gl.

Patented Feb. 5, 1952 UNITED PAT OFFICE IamMillen Ed lf iittit zljfieam, England-I Application September 4, mrnseriali No. 772,057

In Great'Britain September 9, 1946 The present invention relates to machines for intimately mixing or blending ingredients efmix-f tures: together, particularly when in powderor'T comminu-ted form, to obtain a. thoroughly homogeneous product;

Hitherto mixing machines of this-kind have been of two main types. In one type-themixing' takes place in a stationary vessel or hopper; in which is disposed a vane; paddle, or bladestructure which is rotated about a horizontal-101': vertical axis from: which the vanes; or the like, project or radiate.- In the second type, the mixin is eifectedin a vessel ordrum whioh is rotatable" about a horizontal axis; so that the ingredients are tumbled as the vessel" rotates; To enhance the tumbling action it is a common. practice to provide vanes 01" blades fixed. to the interiorv of the vessel or drum, and further to improve; the mixing action, looseobjects such aschains or balls are often placed'in the drum.

The first type of machine has the disadvantage; of requiring a very heavy starting; torquezwhen' the? vane; structure is not started, rotating before, the vesseli is fullycharged with: the; ingredients; in" consequence of which. it is often necessary? to set-the van e structure in motion-heforettheivessel is fully charged; Similarlyzif the-vanerstructure is accidentally" stopped" or h'as to: be: stopped. for some special reasen, .befo1:e: the; mixing; operation is completed, it may become necessary-taunload some of the contents" of the" vessei betorenthe vane'structure can-be started moving agaim to resume themi x-ing operation; *F urthermorewith this type ofmixer there are liliely tote-unmixed pockets of the ingredients-which escape the stirring action of the vanes orthe like, "due- 130 their lodgmenti-n recesses, suclr asdi'scharge: connec! tions; or' inother spaces which are not-swepby thevanes or blades;

r The main disadvantage of the second of mixer is that it is very slow" in action, in;- conse quence' of which a considerahie time" isxtaliem to secure thorough admixture of the in-gredients, atthough the m-ixing action i s very efficient.-

The objectof "thisinventiorr is t'o. provide an im Thdiuht or casing may have a smooth: interi'or; orit may have blades or vanes fixed. there.- to, and the driving mechanisms for the. drum and vane structure-may be such-as to enablethem: to be rotated in the samedirecti'on or in opposite directions In order that the invention may be clearly understood and readily carried into. practice it is illustrated, by way: of" example-only; by the. accoinpanyi-ng'v drawings, which:

Figure I is a sectional diagram offa mixer construeted' in accordance with the. invention; and

Figure-Zisan end elevationthereof.

Referring to the drawings, the: mixing machin comprises; a mixing: drum .A. open. at! one end'but adapted to liezci'osed bya removable cover B. At its closed end" thedrum: A. has an axial hollow spigotshaft: C running in ballibiea-rings; D; mounted'i n acylindrical casing W which'carries a frame structure comprising spaced platesG, supporting an electric motor F? for: driving the drum A. The drive: is efiect'ed from the motor" F, through reduction gearing-incorporated in; the. motor casing; and a drivingbeit passing over a pulley E mountedorr theholfow spigotishait C.

At right angles to: the; axis of the drum A the casing 'W carries trunnions R which are supported by bearings in the fixedframeoi themachine (not shown). By rotation about the trunnions- R the A can be: disposed with its axis horizontaL'a-s in Figure. 1', in the; running position, or it canbe disposed with: its axis verti cal, either in its filling position. FE with itszend open-ingdirected upwardly, when it. canv be charged-0n removal of coverB, or in its emptying' position EP with its end opening directed downwardly, when if its cover'B is removed; its con-tents canhe-dischargedi In addition to means for" rotating" the mixing A as: described above, the machine also incorporates means-ior' rotating a mixing rotor: I-I within the'drum- A, when desired, at a. variable and controlled speed in the reverse direction. to thatof'the Themixing rotorH comprises-a spindle I supporting a plurality of helical blades or vanes by means of'radial arms or spokes". The. spindl'eI is journal-led in suitable bearings at opposite endsiof the drum A and at the closed end of the; drum 'extendsthrough the bearings, and. through the hollow spigot shaft C and pulley E; At its end the spindlfle-Iis solidly: coupled/co a spur; wheel L which formsthe centralpinion of a sun.-andplanet type ofepicyclic gear. The planet pinions Ivf'of the 1 epioycli'e gear: are mounted. on stub fixed in relation to the frame GG by a tubular arm, constituting a bearing tube for a spindle V.

on which is mounted a bell crank lever Q. The

short arm of lever Q is anchored to the other end of the brake band P, so thatby' applying-pressure to the handle of the lever Q the brake band P can be tightened about the rim of the carrier disc 0.

The method of operation of the apparatus is as.

follows:

The mixing drum A is rotated about trunnions R .until its axis is vertical and the drum is in its upper position FP. On removal of the cover B the ingredients to be mixed are loadedinto the drum A and the cover replaced. The drum A is then again rotated about trunnions B into its horizontal running position and the motor F started, with the brake band P released.

The mixing drum A will then rotate. and in doing so it will carry with it the vaned rotor H, due to the friction resulting from the presence of the ingredients to be mixed, the carrier disc 0 being free to rotate. After a few revolutions of drum A the mass of materials will be broken up by the tumbling .action which takesplace.

The brake band P is then graduallytightened, by operating lever Q, about the flange of carrier disc 0, bringing the vaned rotorH gradually to rest, until finally it will commence to accelerate in the opposite direction to drum A, to its maxi mum speed, attained when the carrier disc 0 is held stationary by the brake band P. The actual relationship between the final speeds of the drum A and rotor H will depend upon the rela tive numbers of the teeth of the various wheels constituting the epicyclic gear.

On completion of the mixing'process the elec= tric motor F is stopped and the mixing drum A is rotated about trunnions B into its downwardly directed position EP with its axis vertical. cover B is then removed, and the contents of the drum discharged into a hopper or container. If necessary the motor may be restarted, after removal of cover B, to facilitate such, evacuation, either with, or without application of the brake band P to cause rotation of the vaned rotor H during the discharging process.

The initial mixing process in which the drum A and vane structure H rotate together, without relative motion, will not throw any excessive starting torque on the driving gear, since there will be little or no resistance to rotation of the whole mass in bulk. As soon as rotation starts, the gravitational action on the ingredientsand the' action of static friction will break up the mass of the ingredients by tumbling so that a relative motion can be initiated as between the vane structure and drum, which can be gradually increased by slowing down or speeding up one or other of them, without unduly increasing the 3 driving torque.

It will be appreciated that the tumbling action which occurs will effectively prevent the formation of unmixed pockets of ingredients, whilst the application of relative rotation to the drum and The vane structure will ensure efficient and rapid mixture of the ingredients.

An important use for the improved mixer according to the invention is for the admixture of dye powders, in the nominally dry state, since it is of the highest importance for dye powders to be thoroughly well mixed. This would normally call for the use or an ordinary drum mixer with its consequent long mixing period, whereas the improved mixer according to this invention has the advantage of the drum type of mixer cou- 4 pled with the speed of action of the rotary vane type of mixer.

It shall be clearly understood that the invention is in no way limited to the details of the construction of machine described and illus-- trated, and furthermore that various other constructions of machine embodying individually and/or relative rotatable mixing drum and vaned rotor may be devised, without departing from the scope of the invention. 4

1. A mixing machine including a support having a substantially horizontal bearing; a-horizontal drum with a closed end and an axial spindle disposed within the drum and projecting rotatably out through the closed end of said drum and rotatably through the bearing from one side of said bearing; a vaned rotor formed on the spindle Within said drum; a hollow shaft connected to the drum and rotatably mounted in said bearing and rotatably supporting said spindle externally of one end of said drum; drive means for driving the hollow shaft; transmission means connected to said spindle, drive means and hollow shafton the outer ends of the spindle and hollow shaft; and manually operated control means disposed exteriorly of the side of said bearing and exteriorly of said transmission means effective to selectively cause the drive means to rotate the drum and rotor positively in the same or opposite directions.

2. A mixing machine including a support having a' substantially horizontal bearing; a horizontal drum with a closed end and an axial spindle disposed within the. drum and projecting rotatably out through the closed end of said drum and rotatably through the hearing from one side of said bearing; a vaned rotor formed on the spindle within said drum; a hollow shaft connected'to one end of said drum and rotatably mounted in said bearing and rotatably supporting said spindle externally of one end of said drum; drive means for driving the hollow shaft; transmission means connected to said spindle, drive means and hollow shaft on the outer ends of the spindle-and hollow shaft; manually operated control means disposed exteriorlyof the other side of said bearing and exteriorly of said transmissionmeans effective to selectively cause the drive means to rotate the drum and rotor positively in the same or opposite directions; 'and means for raising said drum, hollow shaft and spindle about a horizontal axis transversely disposed with respect to the axis of said spindle into a substantially upright position for said drum.

3. A mixing machine comprising a cylindrical drum mounted upon an axial spindle projecting from one end ofsaid drum; -a first cylindrical sleeve surrounding the projecting part of said spindle and fixed to the end of said drum, a second cylindrical sleeve surrounding and rotatably supportingthe first sleeve; aligned supporting trunnions projecting from said second sleeve at right angles to the spindle axis; a supporting structure also extending from said second sleeve at right angles to both the trunnion axis and the spindle axis; a driving motor carried by said supporting structure and operative to drive said first sleeve and drum continuously at invariable speed; and controllable transmission means for driving said spindle from said motor at a variable speed andin either direction in relation to the direction of rotation of said drum.

4. A mixing machine comprising a cylindrical drum mounted upon an axial spindle projecting from one end of said drum, a first cylindrical sleeve surrounding the projecting part of said spindle and fixed to the end of said drum; a second sleeve surrounding and rotatably supporting the first sleeve; alined supporting trunnions projecting from said second sleeve at right angles to the spindle axis; a supportingstructure also extending from said second sleeve at right angles to both the trunnion axis and the spindle axis; a driving motor carried by said supporting structure, and operative to drive said first sleeve and drum continuously at invariable speed, a driving pulley mounted on said first sleeve; a brake drum mounted on said spindle adjacent to said driving pulley, flanges on the opposed sides of said pulley and brake drum adapted to form therewith a cylindrical chamber; internal teeth disposed within said flanges, a sun pinion on said spindle; axis pins mounted in said chamber on the side of said brake drums; and planet pinions rotatable on the latter axis pins and meshing both with said sun pinion and also with the internal teeth of both of said flanges on the driving pulley and brake drum; and a manually operated brake device operative on said brake drum to control its speed of rotation between a predetermined maximum speed and a stationary condition.

5. A mixing machine comprising a cylindrical drum having an axial spindle extending there through and projecting from one end of said drum; an elongated sleeve surrounding the projecting portion of said spindle and fixed to said one end of saiddrum; bearing means surrounding and rotatably supporting the elongated sleeve; two aligned supporting trunnions projecting externally in opposite directions from said bearing means at right angles to the spindle axis; a supporting structure also projecting rigidly from said bearing means substantially at right angles to both the trunnion axis and said spindle axis; a driving motor mounted on said supporting structure and operative to drive said elongated sleeve and drum continuously at a predetermined speed of rotation; and controllable transmission means for driving said spindle at variable speed independently of the speed of rotation of said drum.

IAN MILLER EDINGTON AITKEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 102,591 Randall May 3, 1870 600,168 Penn et al. Mar. 8, 1898 749,286 Gerner Jan. 12, 1904 1,234,230 Sturtevant July 24, 1917 1,504,832 Pouget Aug. 12, 1924 1,750,558 Zettergren Mar. 11, 1930 1,859,690 Aeschbach May 24, 1932 1,880,731 Oileau Oct. 4, 1932 2,059,485 Payne et al Nov. 3, 1936 FOREIGN PATENTS Number Country Date 208,360 Germany Mar. 24, 1909 379,823 France Nov. 20, 1907 381,244 France Dec. 31, 1907

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