US2816371A - Heat exchanger mixing mill - Google Patents

Description

Dec. 17, 1957 Filed March 29, 1955 J. J. FISCHER HEAT EXCHANGER MIXING MILL 2 Sheets-Sheet 1 Arrow/var:

Jo/nv J. F/scnar 'Dec. 17 1957 J. J. FISCHER HEAT EXCHANGER MIXING MILL 2 Sheets-Sheet 2 Filed March 29f 1956 vm aw INVENTOR. Jay/v J. FISCHAW 'BY A Arzanvtv:

United States Patent HEAT EXCHANGER MIXING MILL John J. Fischer, East Stroudsburg, Pa., assignor to The Patterson-Kelley Co., Iric., East Stroudsburg, Pa.

Application March 29, 1956, Serial No. 574,923

6 Claims. (Cl. 34-134) This invention relates to material processing devices for use in various industries wherein it is required to simultaneously agitate and dry or heat-treat or cool powdered or granular solid materials, so as to prevent incidental 'caking or agglomeration thereof.

In order to obtain thorough agitation of materials in devices of the character referred to it is essential to provide an action consisting of continuous relative displacemerits and infolding of the large load masses, and in addition thereto a vigorous localized agitation or inten- 'siii'ed blending action. Obviously, intimate in-mixing at the same time of hot air, steam, cool air, etc., as may be called for in any given instance, will provide optimum heat exchange treatment conditions.

It is an object of the present invention to provide an improved mixer and heat treating device employing in combination, the advantages of any rotating tumbler type mixing mill in combination with means designed specifically to provide improved localized agitation and heat treatment of the material particles as the latter are fed thereto by the larger mass mixing operations of the mill.

Another object of the invention is to provide an improved heat treating and blending device as aforesaid which obtains a vastly improved heat exchange and blending action in returnfor application of minimum power.

Another object of the invention is to provide an improved machine as aforesaid which is of structurally simple and rugged form, and which is so constructed as to be most readily and easily cleaned between operations on different materials.

Other objects of the invention will appear in the specification hereinafter.

In. the drawing:

Fig. l is a side elevation of a heat exchange mill embodying the invention, with portions broken away to show the interior thereof;

Fig. 2 is a fragmentary section, on an enlarged scale, showing details of the heat exchange and blending intensifier shaft mounting and driving mechanism; and

Fig. 3 is a fragmentary sectional view taken. along line Ill-HI of Fig. 2.

The invention is shown in the drawing Fig. l as being embodied in a tumbling mill of the type comprising generally a hollow container formed of opposite side leg portions -12 of frusto-cylindrical forrn disposed with their cylinder axes intersecting at approximately 90 and welded together as indicated at 14. The outer ends of the cylinder or leg portions 1'012 are closed by end plates and detachable covers are provided thereon "as indicated at 16-48. The container is fitted at it's opposite sides with integral aligned cylindrical housings 20-20 which have integral hollow stub shaft devices 2-2, 24 which in turn are carried within trunnion bearings 25, 26 respectively, supported upon pede'stalsZT-ZS at opposite, ends of the mill.

The. stub, shaft 22' carries a sprocket- 32 "connected 'by chain, 3.3 to; the min drive motor s t; d thus it 'willbe understood. that application of power from the motor- 34 will cause the mill to rotate upon its trunnion bearings 25--26, whereupon material placed within the mill will be subjected to a generalized admixing and vertical and horizontal infolding action. A discharge spout and control valve therefor as indicated at 35 is supplied for the purpose of emptying the mill subsequent to each blending operation therein. 7

In accord with the present invention it is arranged that the material to be treated within the rotating mill at the same time be subjected to an intensified agitation. For best results this added treatment is localized at a position in line with the path of delivery by the major tumbling operation of a continuous stream of the newly displaced and intermixed larger masses of feed material. Thus, for example, as illustrated in Fig. 1, the intensified action may be obtained by mounting an agitator shaft 36 to extend between the stub shafts 2224 of the tumbler mill; said shaft 36 being fitted with radially extending tubes as indicated at 37-38. The shaft 36 is arranged to be power driven by means of a pulley 29, belt 30, and motor 31 at relatively high speed compared to the speed of rotation of the mill proper. To this end the pulley 29 is keyed to a shaft 39 which is coupled to the shaft 36 as indicated at 40 (Fig. 2) and a pair of bearings as indicated at 41-41 are provided to rotatably mount the shaft 39 in the housing 20, 24. A seal as indicated at 4,2 protects the inner bearing 41.

It will be appreciated that the agitator shaft 36 may be arranged to be readily mountable and dismountable within the mill proper for cleaning or other servicing prior to replacement in the mill for operation upon batches of difierent materials. It is a particular feature of the present invention that whereas the mill proper rotates at a relatively low speed and thereby provides a continuous tumbling and infolding of the large masses of the material load, the agitator shaft 36 is simultaneously driven to rotate at relatively high speed so that the tubes 3738 thereof turn within the down-flowing stream of material load with an intensely rapid motion. The novel construction of the present invention results in ready dispostion of the agitator shaft within the upper level of the material load, and thus the agitator shaft is continuously fed with a downwardly flowing. stream of material and the tubes 3738 thereof impinge against the top layer of this material in such manner and with such rapidity as to pick up the material and throw it free from the main body of the material load. Thus, it will be appreciated that the operation of this shaft produces a very intensive mixing action which is effective against material tending to lump during handling and/or materials tending to smear, or which tend to cling together or which are otherwise difficult to blend.

It is another particular feature and advantage of the invention that the disposition of the agitator shaft at the top surface of the material load of the mill proper enables the shaft to be driven rapidly in return for only a very low power consumption. This is because the agitator is not buried within the load, and thus a greatly improved blending operation is obtained by the mill of the invention in return for only a relatively insignificant increase in power consumption. Whereas, in the drawing the agitator shaft is illustrated as being driven by a separate motor 31, it will of course be understood that the shaft may be driven by any other suitable source of power, such as through a gearing device connected to the drive shaft for the mill proper. The blending mill of the type illustrated herein provides a particularly effective interflow of the large masses of the feed. material in directions horizontally as well as vertically incidental to rotation of the mill, and thus this action when combined with the action of the agitator shaft procures a particularly effective and intimate blending operation 3 upon materials such as are normally diflicult or impossible to properly blend.

It is a particular feature of the present invention that the agitator shaft unit is also employed to function as a novel heat exchange and/or other additive inlet-outlet mechanism. For example, as illustrated in Figs. 2-3, the tubes 37 may be formed with inlet slots as indicated at 50 in communication with the interior of the hollow shaft 36. Thus, a feed tube as indicated at 52 may be coupled to the outer end of the hollow shaft 39, as by means of a conventional gland as indicated at 54, whereupon hot or cold air or gas, or steam, or any other treating or additive liquid or gas may be introduced through the tube 52 into the interior of the shaft 36, while the mill is operating. Thus, as the agitator shaft rotates, the

fluid being introduced through the tube 52 will find egress through the open ends of the tubes 37 extending radially of the agitator shaft; thereby introducing the additive.

material in intimately blending manner into the material load within the mill.

In order to enable the mechanism to accommodate feeding of substantial quantities of air or gas or other fluids through the tube 52 into the mill, the shaft 36 may be blocked intermediately of its length, as by means of a partition block as indicated at 56; and the tubes 38 at the opposite side of the blockade 56 may be arranged to take in air, gas, or the like from the interior of the mill casing for discharge through the opposite end of the hollow shaft 36. Thus, the other end of the shaft 36 is coupled to a second hollow shaft 57 corresponding to shaft 39, as in the manner of the coupling of shaft 36 with the hollow shaft 39; so that the discharging air, gas, or other liquid or light fluid will find egress as indicated at 58 from the open end of the hollow stub shaft 57 (Fig. l). Bearings 41-41 support the shaft 39, 57 in the hollow shafts 22, 24, respectively.

As shown in Figs. 2 and 3, the tubes 38 are slotted as indicated at 59 at positions interiorly of the hollow shaft 36 so that air or gas entering the outer ends of the tubes 38 may travel thereinto and escape through the slots 59 into the interior of the shaft 36, and thence through the discharge as indicated at 58. It should be noted that the slots 50 and 59 of the tubes 37, 38, re-

spectively, are preferably disposed in the side wall por- I tions of the tubes so as to be directed perpendicular to the planes of rotation of the tubes during operation of 'the mill. This minimizes the possibility of travel of solids from the mill into the discharge end portion of the shaft 36; thereby tending to keep the mill contents within the mill proper. However, it will of course be understood that in event the mill is operating on a relatively expensive dust-like material, for example, any dust escaping through the discharge at 58 may be readily recovered by addition of a suitable cyclone or other dust collector device, as is well known in the art.

For example, if the mill is set up to operate upon damp or wet substances, and hot air or the like is introduced through the tubing 52 for the purpose of drying the mill contents, the mill of the present invention will provide at the same time uniform mixing of the mill contents and optimum heat transfer conditions between the inlet hot air and the mill feed contents. Subsequent to drying out of the mill contents, some dust will begin to appear at the discharge point 58 which will signal the end of the drying operation. The mill may then be shut down and discharged as explained hereinabove.

It will also be appreciated that whereas the mill has been illustrated and described as being of the batch type it may also be arranged for continuous operation. in such case the mill feed material may be delivered 1nto the mill as through the tube 52 in the form of a continuous stream, and the finished product will then appear at the discharge outlet 5h as the mill feed material dries up and blows out of the mill.

As shown in the drawing at Figs. 1 and 2, it is preferred to provide the air inlet tubes 37 to be of relatively smaller diameters while the air outlet tubes 38 are of larger diameters. This arrangement causes the additive substances to project into the mill feed material with jet-like actions; thereby contributing to the desired agitation of the mill feed material. On the other hand, egress of discharge air or gas into the outlet tubes 38 s preferably at a lower velocity; and therefore larger diameter tubes are preferred at this position. As shown in Figs. 2 and 3, the inlet and outlet tubes 37-38 are preferably provided with cylindrical caps as indicated at 60, to take the majority of the wear upon the tubes when the mill is operating upon relatively abrasive material. Such caps may be arranged to be slip-fitted or screwthreaded upon the tube ends, and as stated before are optional in use.

It is to be noted that the centrifugal forces developed at the outer ends of the tubes 38 tend automatically to refuse the entrance of solid materials therein. Thus, the tubes 38 function as adequate air or gas escape channels; but reduce the tendencies of any dust or solid materials from entering the tubes to escape from the mill to the discharge 58. Also, it will be appreciated that because the tubes 38 are always in open communication with the interior of the mill and with the atmosphere exteriorly thereof, they function to relieve any accumulations of pressure within the mill such as might result in response to rising temperature conditions or the like and such as might otherwise result in the generation of dangerous pressure conditions.

Although only one form of the invention has been illustrated and described in detail herein, it will be apparent to those skilled in the art that the invention is not so limited but that various changes may be made therein without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. In a material agitating and heat exchange mill, a container for the material to be processed, inlet means for charging said container with material to be processed, outlet means for discharging processed material from said container, means mounting said container for rotation whereby to tumble the material therewithin, a hollow shaft disposed transversely within said container and supported for independent rotation therewithin, said hollow shaft having a plurality of tubular members ex tending diametrically therethrough and radially there from at intervals longitudinally of said shaft whereby said tubular members extend into the material being processed for agitating the latter as the container and the hollow shaft rotate, said tubular members being opened at their opposite ends and being apertured at positions interiorly of said hollow shaft, means for introducing fluid material into one end of said hollow shaft from exteriorly of said mill, means for permitting escape of fluid materials from the other end of said shaft to a position exteriorly of said mill, and partition means disposed intermediately of the opposite ends of said hollow shaft thereby sub-dividing the latter into inlet and outlet end portions, whereby fluid material entering the inlet end portion of said hollow shaft finds escape through some of said tubular members into the material being processed within said container while said material is being agitated by said tubular members, and whereby fluid material within said container finds escape by passing into the outer ends of other of said tubular members to gain access to the interior of the discharge end of said hollow shaft while said tubular members are agitating the material within said container.

2. In a material agitating and heat exchange mill, a container for the material to be processed, inlet means for charging said container with material to be processed, outlet means for discharging processed material from said container, means mounting said container for rotation whereby to tumble the material therewithin, a hollow shaft disposed transversely within said container and supported for independent rotation therewithin, said hollow shaft having a plurality of tubular members extending diametrically therethrough and radially therefrom at intervals longitudinally of said shaft whereby said tubular members extend into the material being processed for agitating the latter as the container and the hollow shaft rotate, said tubular members being opened at their opposite ends and having their side wall portions apertured at positions interiorly of said hollow shaft, means for introducing fluid material into one end of said hollow shaft from exteriorly of said mill, means for permiting escape of fluid materials from the other end of said shaft to a positon exteriorly of said mill, and partition means disposed intermediately of the opposite ends of said hollow shaft thereby sub-dividing the latter into inlet and outlet end portions, whereby fluid material entering the inlet end portion of said hollow shaft finds escape through some of said tubular members into the material being processed within said container while said material is being agitated by said tubular members, and whereby fluid material within said container finds escape by passing into the outer ends of other of said tubular members to gain access to the interior of the discharge end of said hollow shaft while said tubular members are agitating the material within said container.

3. In a material agitating and heat exchange mill, a container for the material to be processed, inlet means for charging said container with material to be processed, outlet means for discharging processed material from said container, means mounting said container for rotation whereby to tumble the material therewithin, a hollow shaft disposed transversely within said container and supported for independent rotation therewithin, said hollow shaft having a plurality of tubular members extending radially therefrom and in open communication With the interior thereof, whereby said tubular members extend into the material being processed for agitating the latter as the container and the hollow shaft rotate, said tubular members being opened at their opposite ends, means for introducing fluid material into one end of said hollow shaft from exteriorly of said mill, means for permitting escape of fluid materials from the other end of said shaft to a position exteriorly of said mill, and partition means disposed intermediately of the opposite ends of said hollow shaft thereby sub-dividing the latter into inlet and outlet end portions, some of said tubular members communicating with said inlet end portion and other of said tubular members communicating with said outlet end portion, whereby fluid material entering the inlet end portion of said hollow shaft finds escape through said some of said tubular members into the material being processed within said container while said material is being agitated by said tubular members, and whereby fluid material within said container finds escape by passing into the outer ends of said other of said tubular members to gain access to the interior of the discharge end of said hollow shaft while said tubular members are agitating the material within said container.

4. In a combination agitating and heat exchanging mill or the like, a container for the material to be processed, inlet means for charging said container with material to be processed, outlet means for discharging processed material from said container, means mounting said container for rotation whereby to tumble the material therewithin, a hollow shaft disposed transversely within said container and supported for independent rotation therewithin, means rotating said container and means rotating said shaft at a relatively higher speed, said hollow shaft having a tubular member extending transversely therethrough and radially therefrom at opposite sides of said shaft whereby said tubular member extends into the material being processed for agitating the latter as the container and the hollow shaft rotate, said tubular member being opened at its oposite ends and being apertured interiorly of said hollow shaft, means for introducing fluid material into one end of said hollow shaft from exteriorly of said mill whereby fluid material entering the inlet end portion of said hollow shaft finds escape through said tubular member into the material being processed within said container while said material is being agitated by said tubular member, and outlet means permitting escape of fluid material from said mill.

5. In a combination agitating and heat exchanging mill or the like, a container for the material to be processed, inlet means for charging said container with material to be processed, outlet means for discharging processed material from said container, means mounting said container for rotation whereby to tumble the material therewithin, a hollow shaft disposed transversely within said container and supported for independent rotation therewithin, said hollow shaft having a tubular member extending transversely therethrough and radially therefrom at opposite sides of said shaft whereby said tubular member extends into the material being processed for agitating the latter as the container and the hollow shaft rotate, said tubular member being opened at its opposite ends and being apertured interiorly of said hollow shaft, means for introducing fluid material into said mill, means for permitting escape of fluid materials from the interior of said shaft to a position exteriorly of said mill, whereby fluid material within said container finds escape by passing into the outer ends of said tubular member to gain access to the interior of said hollow shaft while said tubular member is agitating the material within said container.

6. A mill as set forth in claim 3, wherein said same tubular members are of smaller inside diameter than said other tubular members.

References Cited in the file of this patent UNITED STATES PATENTS 721,890 Henius Mar. 3, 1903 1,669,774 OMalley May 15, 1928 2,677,534 Fischer et a1. May 4, 1954

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