US2306602A

US2306602A - Chilling apparatus

Info

Publication number: US2306602A
Application number: US404117A
Authority: US
Inventors: Bertie S Harrington
Original assignee: Individual
Current assignee: Individual
Priority date: 1941-07-26
Filing date: 1941-07-26
Publication date: 1942-12-29
Anticipated expiration: 1959-12-29

Description

Dec- 29, 1942. BQS. HARRINGTON CHILLING APPARATUS Filed July 2e, 1941 I5 Sheets-Sheet 1 B. S. HARRINGTON CHILLING APPARATUS Filed July 26, 1941 5 Sheets-Sheet 2 lib/W al infinitif:

m- Nl w h .I d im M H. W /f/ I 1mi i w n F l Wu liwuwhw! M we Zine/22107 EATIESHHRR//VGTON M29 Dec. 29, 1942. 5. s. HARRING'N GHILLING APPARATUS Filed July 2e, 1941 5 Sheets-Sheep 3` Patented Dec. 29, 1942 UNITED STATES iATENAT -OFFICE A CHILLING APPARATUS Bertie S. Harrington, Chicago, Ill.

Application July 26, 1941, SerialNo. 404,117.

15 Claims. v(ACI. 62-114) The present invention relates generally to chilling apparatus. More particularly the inven-v tion relates toy that type ofY apparatus which is especially designed to chill, liquid material, Such as lard, compound, or shortening and comprises a hollow cylindrical inner drum, a hollow ringshaped outer drum around the inner drum and with an annular chilling space between it and the inner drum, meansfor circulating a liquid cooling medium through the two drums, means for causing the liquid material to be chilled to flow under pressure through the annular chilling space between the two drums, and a tubular rotor in the 'annular chilling space and with inner and outer Scrapers for scraping the side wall of the inner drum and the inner side wall of the outer drum so as to prevent the material from congealing or freezing thereon during transit or flow through the annular chilling space between the two drums.

One object of the invention is to provide a chilling apparatus of this type which is an improvement upon, and has certain advantages over, previously designed chillingnapparatus of the same general character.

Another object Vof the invention is to provide a chilling apparatus of the type under consideration which is characterized bysimplicity of design and construction, durability or long life, and accessibility of the operating parts including the scraper equipped rotor.

Another vobject of the invention is to provide a chilling apparatus of the type and character under consideration in which the inner and outer Scrapers for scraping the opposed walls of the two drums are of new and improved construction and are mounted on the rotor so that they may be readily removed therefrom.

A further object of theinvention is to provide a chilling apparatus of the type and character provide a chilling apparatus whichiis compact tures which are hereinafter set forth and are more particularly defined by claims at the conclusion hereof.

In the drawing which accompanies and forms a part of this specication or disclosure and in which like numerals of reference denote correspending parts throughout the several views:

Figure l is a front view of a chilling apparatus the vmeans for circulating a cooling medium through. the two drums;

Figure 5 is an enlarged transverse section taken on the line 5-5 of Figure 4 and Showing in detail the: construction and design of the inner and outer Scrapers and the manner in which they are heldin. assembledrelation. with the rotor;

Figure. 6 is a fragmentary side View or elevation of th'e scraper equipped rotor;

Figure '7 is a perspective view of one of the inner Scrapers; and

- Figure 8 is a perspective view of one of the outer Scrapers.

The. apparatus which is shown. in the drawing constitutes .the preferred form -or embodiment of the invention. It is primarily designed l, or adapted to chill for conditioning purposes liquid material, such as lard, compound, or shortening, and Vcomprises an inner drum 9, an outer drumY I0, and a rotor II.

The inner` drum 9 is cylindrical andA is preferably disposed in an upstanding or vertical position. It is mounted on, and projects upwardly from, a disc-like supportingv plate I2 and con- Ssts of a cylindrical side wall I3, a lower head I4, an upper head I5 and a tube I6. The plate I2 extends-horizontally and is supported in an elevated position above a base structure I'I by way of a plurality of laterally spaced legs I8. The lower head |41 of the inner drum rests onl the central portion of the top face of the supporting plate I2 and is' bolted to such plate in order that the inner drum is in xed relation with the plate I2'. The side wall I3 of the inner drum is formed of thin metal for heat transfer purposes. The lowerv end of the side wall is welded. or otherwise securedto the outer man gin or peripheral portion of the lower head I4, as shown in Figure 4. The upper head I of the inner drum serves as a closure for the upper end of the side wall I3 and is welded to the upper end of the latter. The lower head I4 is provided with a central upstanding enlargement I9 and this serves as a supporting medium for the tube I6. The latter is positioned within the central portion of the side wall I3 and is spaced from the latter in order to form an annular space between it and said side wall I3. The lower end of the tube rests on, and is welded or otherwise fixedly secured to, the upper end of the.

enlargement I9. The upper end of the tube I6 is open and terminates beneath the upper head I5 of the inner drum so that the interior of the. tube is in communication with the upper end of the annular space 20. A spiral baille 2| is disposed in the space 20 and suitably secured to the outer face of the tube I6 and the inner face of the side wall I3. A liquid cooling medium, such as brine or a refrigerant, is circulated through the inner drum by way of a vertically extending inlet pipe 22 and a vertically extending outlet pipe 23. The inlet pipe 22 is located between the plate I2 and the base structure-I1 and is centrally positioned with respect to the plate supporting legs I8. The lower end of the pipe 22 is connected to a source of the cooling medium and is adapted to receive the cooling medium under pressure. The upper end of the inlet pipe 22 extends through a hole in the central portion of the plate I2, is connected to the lower head I4 of the inner drum by way of a screw thread connection, and communicates with the lower interior portion of the tube I6 by Way of a Vertical duct 24 in the central enlargement I9 of the lower head I4. When the apparatus is in operation and the cooling medium is delivered to the pipe 22 under pressure such medium flows upwards through the duct 24 into the lower end of the tube I6. Thereafter it flows upwards through the tube and thence downwards through the annular space 29 between the tube and cylindrical side wall I3. Due to the spiral baffle 2| the cooling medium is caused to flow in a helical or spiral course as it travels or passes through the annular space 26. The outlet pipe 23 serves as a return for the cooling medium. It is positioned in side by side relation with the inlet pipe 22, as shown in Figure 4. The upper end of the outlet pipe extends through a hole in the central portion of the supporting plate I2, is connected to the lower head I4 by a screw thread connection, and communicates with the lower end of the annular space 20 by way of an L-shaped duct 25 in the enlargement I 9. The lower end of the outlet pipe is connected by any suitable piping to return the spent cooling medium to the source of the cooling medium. The cooling medium, as it flows spirally through the annular space 20 between the tube I6 and the cylindrical side wall I3, serves to refrigerate the side wall. i

The outer drum I0 is ring-shaped and extends vertically. It is positioned around and in concentric relation with the inner drum 9 and consists of a cylindrical inner side wall 26, a cylindrical outer side wall 21, a ring-shaped lower head 28, and a ring-shaped upper head 29. The inner side wall 26 is of greater diameter than the cylindrical side wall |`3 of the inner drum 9 and defines with the side wall an annular chilling space through which the material to be chilled is caused to flow as hereinafter described. The

cylindrical outer side wall 21 of the outer drum surrounds, and is spaced from, the cylindrical inner side wall 26 and denes with the latter an annular space 3|. The lower ring-shaped head 28 serves as a bottom end closure for the space 3|. It rests upon, and is bolted or otherwise xedly secured to, the marginal portion of the supporting plate I2 and is welded to the lower ends of the inner and outer side walls 26 and 21 of the outer drum. The upper ring-shaped head 29 serves as a closure for the upper end of the annular space 3| and is welded, or otherwise suitably connected, to the upper ends of the inner and outer side walls 26 and 21. A liquid cooling medium, such as brine or a refrigerant, is circulated through the annular space 3| by way of a horizontally extending inlet pipe 32 and a horizon-tally extending outlet pipe 33. The inlet pipe 32 is adapted to receive the cooling medium under pressure in the same manner as the inlet pipe 22 for supplying the cooling medium into the lower end of the tube I6. It is joined to the lower portion of the cylindrical outer side wall 21 of the ring-shaped outer drum I6 and communica-tes with the lower end of the annular space 3| by way of a hole or aperture in the lower end of the wall 21. The outlet pipe 33 serves as a return for the spent cooling medium and is connected to the upper end of the outer side wall 21. It is positioned in parallel relation with the inlet pipe 32 and communica-tes with the upper end of the annular space 3| by way of a hole or aperture in the side wall 21. A spiral or helical baiile 34 is disposed in the space 3| between the side walls 26 and 21 and serves to cause the cooling medium to flow in a spiral course through said space 3|. When the apparatus is in operation the cooling medium which is supplied to the ring-shaped outer drum I0 enters the lower end of the annular space 3| via the inlet pipe 32, then ows in a spiral course through the space 3| and is nally returned to the source of supply by way of the outlet pipe 33. The cooling medium during travel through the space 3| serves to refrigerate the cylindrical inner side wall 26 of the outer drum I0. If desired a jacket of asbestos or other insulating material may be applied to the outer side wall 21. of the outer drum ID in order to insulate such side wall from the surrounding atmosphere. The lower end of the annular chilling space 3|! is closed by the supporting plate I2, as best shown in Figure 4, and the upper end of such space is closed by a head 35. The latter rests upon, and is bolted to, the upper ring-shaped head 29 of the outer drum I3. The upper head I5 of the inner drum 9 is imperforate and positioned a short distance beneath -the central portion of the head 35. The material to be chilled is introduced into the lower end of the annular space 3B by way of an inlet pipe 36. The latter is connected by a screw thread connection to a boss on the supporting plate I2 and communicates with the lower end of the space 30 by way of an L-shaped duct 31 in the boss and plate. It is contemplated that the material to be chilled will be delivered to the pipe 36 while it is under pressure. After entering the space 30 the material to be chilled ows upwards and is chilled or cooled as a result of contact with the cylindrical side wall I3 of the inner drum 9 and the cylindrical inner side wall 26 of the outer drum I0. The material, after being chilled or cooled to the desired extent due to transit or passage through the space 30, is discharged by way of a horizontally extending outletpipe 38. This pipe asoaeoa is connected to a boss in the head 35,and communicates with the upper end of the annular chilling space by way of an L -shaped duct-39. The rotor II is adapted to be driven continuously at a comparatively low speed during operation of the apparatus. It comprises a thin tubular body 40, an end wall 4I and a drive shaft 42 and, as hereinafter described, has inner Scrapers 43 and outer scapers 44 for scraping the cylindrical side wall I3 of the inner drum and the cylindrical inner side wall 26 of the outer drum in order to prevent the material to be chilled from congealing or freezing on such walls during passage or ow through the annularV chilling space 30 between the two drums. The tubular body 4D of the rotor extends vertically and is concentrically arranged with respect to the inner and outer drums 9 and I0. It is disposed in the annular chilling space 30 and spaced equidistantly from the side walls I3 and 26. The lower end of the rotor body 4B is open, as shown in Figure 4, in order that a portion of the material to be chilled flows upwards between the inner face or periphery of the body 4i) and the outer face of the side wall I3 while the remainder flows upwards between the rotor body and the inner side wail 26 of the outer drum I0. The end wall 4I of the rotor overlies and is spaced above the upper head I5 of the inner drum 9. It extends across and is welded or otherwise xedly secured to the upper end of the rotor body and has anA annular series of holes 45 therein for permitting the material in the upper end of the rotor to flow into the duct 39 and thence to the outlet pipe 38. The upper face of the end wall 4I is positioned beneath the lower bottom face of the head so that the portion of the material which flows through the holes is permittedto flow into the duct 39. The shaft 42 extends vertically and is driven, as hereinafter described, so as to effect rotation of the rotor and the desired scraping of the opposed or opposite side walls of the two drums. The lower end of the shaft is xedly secured to the central portion of the end wall 4I and is journallcd in a bearing 46 on the central portion of the head 35. The upper end of the drive shaft is journalled in a bearing t1 which, as shown in Figure 1, is carried by a plate 48. The latter is held in an elevated position above the head 35 by way of a plurality of upstanding legs 49. If it is desired t-o remove the rotor from its operative position for repair or inspection, purposes it is Ionly necessary to rem-ove the bolts for the head 35. Proper loosening of such bolts results in loosening of the head so that it makes it' possible to remove the rotor from its operative position by raising the head with respect to the two drums. So far as `the chilling apparatus which is illustrated in the drawing is concerned the rotor is driven in a clockwise direction as shown in Figure 5.

The inner and outer Scrapers are mounted on the tubular body 45 of the rotor II and are arranged so that they are in superposed annular series. Preferably there are two inner Scrapers and two outer scrapers in each annular series and the two inner Scrapers are arranged one diametricaliy opposite the other and the two outer Scrapers are arranged one diametrically opposite the other and at right angles to the inner Scrapers. As shown in Figure 6,v the Scrapers of each annular series are laterally offset with respect to the Scrapers of the adjoining series. The inner lScrapers are in the form of sheet metal stamping-S and consist of substantially flat leading margins 50, flat trailing margins 5I, and outwardly bulged or arched central portions 52. The body of the rotor is provided with a vertically extending front slot 53 and a vertically extending rear slot 54 for each of the inner scrapers 43. The front slots are disposed directly Yin front of the rear slots 54 and are separated from the latter by bar-like elements 55. As best shown in Figure 5, the outwardly bulged central portions 52 of the inner Scrapers extend around or are in straddled relation with the outer faces of the bar-like elements 55. The flat trailing margins 5I abut against the inner faces of the portions of the rotor body which dene the rear edges of the slots 54 and the substantially flat leading margins of the inner Scrapers extend inwardly and also forwards with respect to the direction of rotation of the rotor and abut against the inner corners of the portions of the rotor body that define the front edges of the front slots 53. The front or leading edges of the Scrapers 43 are straight and engage the outer periphery or surface of the cylindrical side wall I3 of the inner drum 9 with inward pressure. The inward presure to which the leading edges of the inner Scrapers 43 are subjected is attributable to the fact that the bulge of the central portions of the Scrapers is of less magnitude than the thickness of the bar-like elements 55 and as a result when the Scrapers are in place, i. e., in assembled relation with the body of the rotor, the elements 55 exert such outward pressure on the outwardly bulged central portions 53 of the Scrapers that the front or leading margins of the Scrapers are'caused to swing'inwards into spring contact with the side wail i3 of the inner drum. The inner corners of the portions of the rotor body that dene the front portions of the edgesof the slots 53 serve l as fulcrums for the leading margins 50 of the inner Scrapers and hence outward bowing of the central portions of the Scrapers due to the action of the bar-like elements 55 places the leading margins of the inner scrapers under the desired inward pressure. In addition the outward bowing of the central portions of the inner scrapers resulting from the action of the elements 55 resuits in the at trailing margins of the inner scrapers'engaging the adjacent face portions of the rotor body with outward pressure. The ends of the rear slots 54 terminate inwardly of the ends of' the front slots 53 and are defined by shoulder-like parts 56 which are integralwith the rotor body. These shoulder-like parts t within cutouts or notches 5l in the rear or trailing corners of the inner Scrapers and prevent rearward displacement of the inner Scrapers with respect to the rotor yduring drive of the rotor. In assembling the rotor the inner Scrapers 43 are first placed inside the rotor. Thereafter the trailing margins 5I of the Scrapers are inserted through the slots 53. The Scrapers are then manipulated so as to bring the trailing margins into place and the outwardly bulged central portions 52 into Straddled relation with the bar-like elements 55. Two vertically spaced comparatively wide slots 58 are formed in the rotor body 45 directly in front of each front slot 53. These slots 58 are positioned in opposed relation with the leading margins of the inner Scrapers and permit the portion of the material to be chilled that is on the inside of the rotor to flow to the outside of the rotor after scraping thereof by the Scrapers 43. rlhe leading margin 5I) of each of the inner Scrapers is provided with a vertical series of equi-distantly .spaced holes 59 and these holes permit a portion of the material on the inside of the rotor body to ow through the inner Scrapers. In addition these holes prevent the material to be chilled from accumulating between the inner portions of the leading margins of the inner Scrapers and the adjacent parts of the rotor body, i. e., the parts between the slots 59 and the front slots 53. The outwardly bulged central portions of the inner Scrapers 43 are provided with holes 60 so as to permit passage of the material to be chilled through the slots 54. The inner Scrapers of each series are of such length and are so arranged that their ends lap the ends of the inner Scrapers of the adjacent or adjoining Series. As a result of this arrangement the inner Scrapers serve during drive of the rotor II to scrape the entire outer periphery of the cylindrical side wall I3 of the inner drum 9.

The outer Scrapers 44 serve to scrape the entire inner face or periphery of the inner side wall of the ring-shaped outer drum I0. 'Ihey are in the form of one-piece sheet metal stampings and consist of flat leading margins 6I, inwardly offset flat trailing margins 62 and flat central portions 63. The central portions 63 serve to cross connect and extend at substantially7 right angles to the leading and trailing margins 6I and 62. As a mounting means for each of the outer Scrapers 44 the body 46 of the rotor is provided with a vertically extending slot 64. The outer Scrapers are arranged so that the leading margins thereof extend outwardly and forwardly in that portion of the annular chilling space 38 which is between the rotor body and the inner side wall of the outer drum I0. The flat central portions 63 are positioned in abutment with the rear portions of the slots 64 and the flat trailing margins 52 are in lapped relation with the inner faces of the portions of the rotor body that define the rear portions of the slots 64, as shown in Figure 5. The front edges of the leading margins of the outer Scrapers are straight and engage the inner periphery or surface of the inner side wall of the drum I8. The leading margins 6I abut against and are urged outwards by the portions of the rotor body that define the front portions of the slots 64 with the result that the leading edges of the outer Scrapers engage the inner side wall of the outer drum with outward pressure. In order to prevent Sidewise displacement of the outer Scrapers with respect to the slots 64, block-like lugs 65 are provided. These blocks are disposed in front of, and are welded or otherwise xedly Secured to, the central portions 63 of the Scrapers 44. They t snugly within the central portions of the slots 64, as shown in Figure 5. Two vertically spaced elongated slots 66 are formed in the rotor body 40 directly in front of each of the slots 64. These slots 66 permit the material which is scraped by the outer Scrapers to flow to the inside of the rotor body for contact with the cylindrical side wall I3 of the inner drum 9. Holes 61 are formed in the leading margins 6I of the outer Scrapers so as to permit a portion of the material to flow past the Scrapers and to prevent the accumulation of material between the inner portions of the leading margins of the Scrapers and the adjacent portions of the rotor body. The outer Scrapers of each annular series are of such length and are so positioned that the ends thereof are in lapped relation with the ends of the outer Scrapers in the adjoining series. Because of this the entire inner periphery of the inner side wall of the ring'- shaped outer drum is scraped during rotation of the rotor 9. When the apparatus iS in use the inner Scrapers in connection with drive of the rotor 9 operate to scrape the material from the Side wall I3 and such material, due to the deflecting action of the leading margins of the inner Scrapers, is caused for the most part to flow to the outside of the rotor body via the slots 58. The outer Scrapers 44 operate, as hereinbefore described, to scrape the inner surface of the inner side wall of the outer drum I0 and cause the scraped material to flow to the inside of the rotor body via the slots 66. During drive of the rotor the material, due to the action of the scrapers, is caused as it travels upwards through the annular chilling space 20, to ow back and forth between the inside and outside of the rotor body. Due to the fact that the material is caused to travel back and forth via the

slots

58 and 66 effective agitation of the material is effected.

'I'he rotor II of the apparatus is driven by means of an electric motor 68, a speed reducing unit E9, a vertically extending shaft I0 and a chain and Sprocket connection 1I. The electric motor 68 is mounted on the base structure I1 and is positioned to one side of the outer drum I0. 'Ihe speed reducing unit 69 is also mounted on the base structure I1. It is connected for drive by the armature shaft of the electric motor 68 and serves to drive the vertically extending shaft 10. The latter is disposed in parallel relation with the outer drum I0 and has its upper end journalled in a bearing 12 which is carried by the plate 48 on the legs 48. The connection 1I comprises a sprocket 'I3 on the upper end of the shaft II), a sprocket wheel I4 on the upper end of the rotor driven shaft 42 and an endless chain 15 around the sprocket and Sprocket wheel.

When the apparatus is in operation the cylindrical Side wall I3 of the inner drum 9 is refrigerated due to the downward passage of the cooling medium through the annular space 20 and the inner side wall of the outer ring-shaped drum I0 and is refrigerated due to the upward flow of the cooling medium through the annular space 3|. As the material to be chilled flows upwards through the annular chilling Space 38 it contacts with, and is chilled by, such walls. The material during upflow thereof through said annular Space 30 is subjected to the action of the inner and outer Scrapers and is caused to flow back and forth between the inside and outside of the rotor body 40. When the material reaches the upper end of the chilling space 30 it is forced through the L-shaped duct 38 and thence into the outlet pipe 38. Due to the fact that the liquid cooling medium flows downwards through the annular space 2!) in the inner drum and upwards through the annular space 3| in the outer drum I0 the material is subjected to a Substantially uniform chilling temperature as it flows upwards from one end of the annular chilling Space 30 to the other.

The herein described chilling apparatus is both rugged and durable and effectively and eiciently fulfills its intended purpose. It is in the form of a compact unit and is characterized by the fact that the various operating parts, such, for example, as the scraper equipped rotor and the head 35, are readily removable for repair 0r inspection purposes. Because of the interlocking connections between the Scrapers and the rotor body the Scrapers may be readily removed when the rotor is withdrawn from the chilling space 30.

Whereas the apparatus has been described as being particularly designed for use in connection with chilling lard, compound, or shortening it is -to be understood that it may be, used toV chill Iother kinds of liquid materials. It is also to be understood that the ,invention is not to be restricted to the detailsA set forth since these may be modified within the scope of the appended `claims without departing from the spiritl and scope of the invention.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

1. A chilling apparatus comprising a cylindrical refrigerated wall adapted to have the material to be chilled flow past one face thereof, and a rotor embodying a tubular body positioned in spaced and concentric relation with said one face of the wall and having slots therein, and removable scrapers for. scraping the wall in connection with drive of the rotor embodying free leading portions with scraping edges in contact with said one face of the wall and trailing portions in interlocked relation with the slots.

2. A chilling apparatus comprising a cylindrical refrigerated wall adapted to have the material to be chilled flow past one face thereof, and a rotor embodying a tubular body positioned in `spaced and concentric relation with said one face of the wall and having openings therein and longitudinal slots behind the openings, and removable scrapers for scrapingthe wall in connection longitudinal slots therein, and removable scrap- L ers for scraping the wall in'connection with drive of the rotor embodying'free leading portions extending outwards from the body and provided with straight scraping edges in contact with said inner face of the wall, and in addition embodying trailing portions in interlocked relation with the slots.

4'. A chilling apparatus comprising in combination, a cylindrical refrigerated wall adapted to have the material to be chilled flow past the outl,

er face thereof, and a rotor embodying a tubular body of greater diameter than the wall around and positioned in spaced and concentric relation with the wall and having longitudinal slots therein, and removable Scrapers for scraping the wall in -connection with drive of the rotor embodying free leading portions extending inwards "from the body and provided with straight scraping edges in contact with said outer face of the wall, and also embodying trailing portions in inf' terlocked relation with the slots.

5. A chilling apparatus comprising in combination, a, pair of cylindrical concentric refrigerated walls with an annular chilling space therebetween through which the material to be chilled is adapted to flow, and a rotor embodying a tubular body positioned in said space in spaced and concentric relation with the walls and having openings therein and longitudinal slots behind the openings, inner Scrapers for scraping the inner wall embodying free leading portions positioned inwardly of the body and adjacent certain of the openings and trailing portions in interlocked relation with the slotsbehind said certain openings, and outer scrapers for scraping the. outer` wall embodying free leading portions positioned outwardly of the body and adjacent the other openings and trailing portions in interlocked relation with the slots behind said other openings.

6. A chilling apparatus comprising a cylindrical refrigerated wall adapted to have the material to be chilled now past one face thereof, and a rotor embodying a tubular body positioned in spaced and concentric relation with-said one face of the wall and having a pair of side-by-side longitudinal slots therein, and a removable scraper for scraping the wall in connectionwith drive of the rotor embodying a free leading portion extending away from the rotor body in the direction rof the wall andwith a'straight wall-engaging scraping edge and also embodying a bowedl trailing portion threaded through the two slots and in straddled relation with theportion of the body that is disposed between said slots.

'7. A chilling apparatus comprising a cylindrical refrigerated wall adapted'to have the material to be chilled flow past one face thereof, and

`a rotor embodying a tubular body positioned in spaced and concentric relation with said one face of the wall and having a pair of side by side longitudinal slots therein, and a removable scraper for scraping the wall in connection with drive of the rotor embodying a substantially flat leading margin extending away from one face of the rotor body in the direction of the wall, a bowed intermediate portion extending through the two slots and in straddled relation withthe portion'of the body between the slotsyand a lsubstantially flat trailing margin in lapped relation with the portion of the body that-is'rearwards of the rearmost slot.

8. LA chilling apparatus comprising in combination 'a cylindrical refrigerated wall adapted to have the materialr to be chilled flow pastone face thereof, andl a rotorembodying a tubular body positioned in concentric and spaced relation with said one face of the wall and having a pair of longitudinally extending side by side slots therein, and a removable scraper for scraping the wall during rotation of the rotor having a free leading portion extending away from the rotor body in the direction of the wall and with a straight wallengaging scraping edge and also having a, bowed trailing'portion threaded through the two slots and in straddled relation with the portion of the body that is between said slots and arranged so that it serves to urge the leading portions into spring contact with said wall.

9. A chilling apparatus comprising in combination a pair of -cylindrical concentric refrigerated walls with an annular chilling space therebetween through which the material to be chilled is adapted to iiow, and a ro-tor comprising a tubular body tting within said space and in spaced relation with the two walls and provided with an opening therein and a pair of side by side longitudinally extending lslots behind the opening, a removable scraper for scraping one of the walls during rotation of the rotor having a free leading portion adjacent the opening and extending away from the rotor body in the direction of the one wall, and also having a bowed trailing portion threaded through the two slots and in straddled relation with the portion of the body that is Vface of the wall and having a longitudinal slot therein, and a removable scraper for scrap-ing the wall in connection with rotation of the rotor embodying va free leading margin extending away from the body portion in the direction of the wall and provided with a straight scraping edge in Contact with said one face of the wall, a central portion extending at right angles to the leading margin and loosely through the slot, and a trailing margin in lapped relation with the portion of the rotor body that denes the rear portion of the slot, said scraper also having means associated with the central portion for preventing sidewise displacement of the scraper with respect to the rotor body.

11. A chilling apparatus comprising a cylindrical refrigerated wall adapted to have the material to be chilled flow past one face thereof, and a rotor embodying a tubular body positioned in spaced and concentric relation with said one face of the wall and having a longitudinal slot therein, and a removable scraper for scraping the wall in connection with rotatie-n of the rotor embodying a free leading margin extending away from the body portion in the direction of the wall and provided with a straight scraping edge in contact -with said one face of the wall, a central portion extending at right angles to the leading margin and loosely through the slot, and a trailing margin in lapped relation with the portion of the rotor body that deiines the rear portion of the slot, said scraper also having a lug associated with its central portion and fitting in the slot for holding the scraper against sidewise displace-v ment'with resp-ect to the rotor body.

12. A chilling apparatus comprising in combination a cylindrical refrigerated wall adapted to have the material to be chilled flow past one face thereof, and a rotor embodying a tubular body positioned in concentric and spaced yrelation with said one face of the wall and having a longitudinally extending slot therein, a removablescraper for scraping the wall during rotation of the rotor having a trailing margin in lapped relation with that portion of the rotor body that defines the rear part of the slot, a central portion extending at substantially right angles to the trailing margin and loosely through the slot and a comparatively wide substantially at free leading margin extending away from the rotor body in the direction of the wall and engaging the wall with spring pressure, said scraper also having means associated with the central portion and between said slots and arranged and positioned longitudinally extending slots behind the opening and also provided with a second opening and a single longitudinally extending slot behind the last mentioned opening, a removable scraper for scraping one of the walls during rotation o'f the rotor having a free leading portion adjacent the rst mentioned opening and ,extending away from the rotor body in the direction of said one v wall and also having a bowed trailing margin threaded through the two slots and in straddled relation with the portion of the body that is be' tween said slots, and a second scraper for scraping the other wall having a free leading portion adjacent the second openingl and extending away from the rotor body in the direction of said other wall and a trailing portion in interlocked relation with the single slot.

14. A chilling apparatus of the character described including an inner `drum embodying a cylindrical side wall, heads at the ends of said side wall and a tube' within the side wall spaced from the latter so as to form therebetween an annular space and having one end thereof fitting against, and secured to, the head and its other end open and terminating inwardlyof the other head, and means for circulating a liquid cooling medium througnthe inner drum in order to refrigerate the side wall including a pipe incommunication withthe interior of said one end of the tube, and a pipe communicating with the end of the annular space that is 'adjacent said one head, a hollow ring-shaped outer drum around the inner drum and with an annular space therebetween for the passage or the material to be chilled. I

15. A chilling apparatus of the character de- Y scribed including an inner drum embodying a cylindrical si-de wall, heads at the ends of said side wall, a tube within the side wall spaced from the latter so as to form therebetween an annular space and having one end thereof fitting against and secured to, the head andi-ts other end open and terminating inwardly of the other. head, and a spiral baille in said annular space; and means vfor circulating a liquid cooling medium through the drum including an inlet pipe communicating with the interior of said one end of the .tube and an outlet pipe in communication with the end of the annular space that is adjacent said one head.

BERTIE S. HARRINGTON.