US3248803A - Rotary drum heat exchanger - Google Patents

Description

May 3, 1966 G. KRIKORIAN ROTARY DRUM HEAT EXCHANGER 3 Sheets-Sheet 1 Filed April 5, 1963 May 3, 1966 Filed April 5, 1963 e. KRIKORIAN 3,248,803

ROTARY DRUM HEAT EXCHANGER 3 Sheets-Sheet 5 United States Patent M 3,248,803 ROTARY DRUM HEAT EXCHANGER Garo Krikorian, Worcester, Mass., assignor to Rice Barton Corporation, Worcester, Mass., a corporation of Massachusetts Filed Apr. 5, 1963, Ser. No. 270,919 4 Claims. (Cl. 34-110) The present invention relates to improvements in rotary drum heat exchangers.

The invention is shown in two alternative forms, in one form as embodied in a drum-type dryer having a heated outer shell, and in an alternative form as embodied in a cooling roll having a cool outer shell.

In a preferred form of the invention, a rotary drum dryer is disclosed having a drum of large diameter which comprises a shell, 21 supporting rotary hub rotating on a fixed axis, and supporting disc or spoke elements which project outwardly from the hub and provide support for the drum. The drum is fitted with a heating system which may comprise a network of pipes through which a heating medium, preferably steam, is circulated about an area adjacent the shell surface to maintain a desired temperature of the external surface of the shell. Dryers of the type referred to are built to operate at high speeds and with a drying surface heated to increasingly high temperatures with the result that difiiculty has been experienced in providing a strong drum structure which will provide adequately for the expansion and contraction of the heated shell portion of the drum and will, at the same time, insure that the rapidly rotating shell is at all times adequately supported and held in a coaxially aligned position with relation to the hub axis.

In an alternative embodiment of the invention, a cool ing roll is disclosed which comprises two solidly formed end discs, an outer shell which is secured at each end to said discs to rotate on a fixed axis, and an inner shell which cooperates with the outer shell for the circulation of the cooling medium such as water between said shells. In a structure of this type also, the difierence in the amount of expansion and contraction experienced in the end discs and in the relatively colder outer shell has presented problems.

It is an object of the invention to provide a novel and improved drum structure including a series of expansion joints in said structure so constructed and arranged that they will permit the shell, heated or cooled as the case may be, to expand and to contract freely with relation to the relatively constant temperature hub and radial supporting parts of the drum and which will, at the same time, maintain the shell securely in an exactly centered and longitudinally determined position with relation to the hub axis.

A preferred embodiment of the invention comprises a rotary drum heat exchanger having a shell with an external heat exchanging surface, a rotary hub, and a plurality of disc headers mounted on the hub for supporting the shell, said heat exchanger being provided with a series of expansion joints connected between each said disc header and said shell around the periphery of said disc header, each said expansion joint comprising .a pin and sleeve connection interconnected between said disc header and shell permitting relative movement of the interconnected portions of said disc header and shell only along a line radially of said drum axis. The arrangement is such that the portion of the shell at the location of each said expansion joint is freely adjustable only in a radial direction with relation to said hub, while at the same time that portion of the shell is fixedly secured tangentially with relation to said disc header. The tangential support provided at each of a plurality of such locations combines Patented May 3, 1966 to maintain said shell in a fixed position coaxially with said hub.

In order to provide for expansion and contraction of the shell relatively to the rotary hub longitudinally, only one of the disc headers is rigidly secured to the rotary hub. Any other said disc header is connected to the rotary hub by means of a series of axial expansion joints connected between the said disc header and said rotary hub, each said axial expansion joint comprising a sleeve and pin connection interconnected between said disc header and said rotary hub permitting relative movement of the disc header and said rotary hub only along a line parallel to said hub axis.

In the alternative embodiment of the invention shown, the outer shell of the cooling drum is supported coaxially with relation to the end supporting discs by means of radial pins which are secured at their outer ends directly into the outer shell and are fitted into sleeve sockets formed in the peripheral surface of the end discs.

With the above and other objects in view as may hereinafter appear, the several features of the invention consist in the devices, combinations and arrangement of parts hereinafter described and claimed which together with the advantages to be obtained thereby will be readily understood by one skilled in the art from the following description taken in connection with the accompanying drawings in which:

FIG. 1 is .a view in end elevation of a rotary drum dryer, but with the adjacent disc header removed, illustrating the several features of the invention;

FIG. 2 is a view in side elevation of the rotary drum dryer shown in FIG. 1;

FIG. 3 is a detail view on a large scale and in section of the lower portion of the drum shown in FIG. 2;

FIG. 4 is a fragmentary view of the drum in end elevation illustrating one of the fastening devices for securing the drum to the disc header;

FIG. 5 is a detail sectional view taken on a line 55 of FIG. 3 illustrating one of the expansion joints; and

FIG. 6 is a view partly in section of a modified form of the invention as shown in a cooling roll.

Referring to the drawings, the invention is herein disclosed in a preferred form in a rotary drum dryer of the general type having a rotary drum 10 of substantial diameter consisting of a sleeve hub 12 supported in sleeve bearings, not shown, and a shell 18 which is supported with relation to the hub by means of two perforated disc headers 20, 22. The shell has formed therein adjacent the outside peripheral surface a series of parallel longitudinally extending conduits 24. At the ends of the shell there are provided manifolds 26, 28 in the form of steel pipes which are bent into a circular form having the same diameter as the shell, and abut the two ends of the shell. The manifolds extend entirely around the drum. Each conduit 24 is tapped at its two ends into the respective manifolds.

Steam is passed through the manifolds 26, 28 and conduits 24 by means of a steam supply system which comprises a steam inlet junction 30 and a large diameter pipe 32 fitted within the sleeve hub 12 through which steam is introduced into the drum and a condensate outlet junction 34 and a small diameter condensate outlet pipe 36 fitted within the inlet pipe 32 through which condensate is withdrawn from the drum. The steam inlet pipe 32 and condensate outlet pipe 36 are connected with the manifolds 26, 28 through connecting pipes which form no part of the present invention and are therefore not here further referred to.

In accordance with the invention, the supporting structure for the drum shell 18 including the disc headers 20, 22 is constructed and arranged to provide a drum structure of maximum strength and rigidity while at the same time permitting to the shell 18 complete freedom to expand and contract in accordance with the varying thermal conditions. The disc headers 20, 22 which, in the embodiment shown are constructed of heavy material, are divided into outwardly disposed rims or ring members 46, 48 which are rigidly secured by an axially extending bolt 50 to inwardly extending flanges 52, 54 formed at the respective ends of the shell 18, and inner core disc members 56, 58 which are mounted respectively on the hub discs 60, 62 which are fixedly mounted on the sleeve hub 12 of the drum assembly. In the embodiment shown, the core disc members 56, 58 are positioned in the same transverse planes respectively with the outwardly disposed rims 46, 48 and are spaced therefrom a sufiicient amount to allow for any relative expansion or contraction thereof. In order to provide a rigid axially centered support for the shell 18 on the core discs 56, 58, there are provided at evenly spaced intervals around the periphery of each disc header twelve identical expansion joints, generally designated at 66 comprising sleeve and pin connections interconnecting said rims 46, 48 and said core disc members 56, 58, each said sleeve and pin connection permitting relative movement of the interconnected portions of said rim and core disc members only along a line radially of said drum axis. Said expansion joints have the effect of securing the rim 46 or 48 to the associated inner core disc member 56 or 58 in such a manner that the engaged portion of the rim is permitted to move freely in a radial in and out direction, but is positively secured against transverse movement with relation to the core disc in any direction. Inasmuch as these expansion joints are identical in their construction and mode of operation, only one such joint will be specifically described in connection with FIGS. 35, inclusive. As shown in these figures, the expansion joint 66 comprises a metal block 68 formed with a pin receiving bore and bolted to the core disc member 56 adjacent the peripheral edge thereof. A similarly formed block 70 is bolted to the rim 46 radially outwardly from the block 68 and is similarly formed with a radial pin receiving bore providing a pin receiving sleeve element in alignment with the bore formed in the block 68. A guiding pin 72 extends through both of said bores and is press fitted and pinned into the bore of the block 68 being, however, slidably fitted within the sleeve element provided by the block 70 and bore therethrough. With this arrangement, it will readily be appreciated that the portion of the shell, controlled by each expansion joint including the guiding pin 72, is free to move radially inwardly and outwardly as the shell contracts or expands, being, however, rigidly secured against any lateral movement by engagement with the respective guiding pin 72.

In the illustrated construction, provision is made also for expansion and contraction of the shell in an axial direction. Further in accordance with the invention, expansion joints are provided between the sleeve hub 12 of the drum and one of the core header discs on which the shell 18 is carried. As best shown in FIGS. 1 and 2 of the drawings, the header core disc 56 is rigidly secured to the hub disc 68 by bolts 76. The header core disc 58, on the other hand, is supported with relation to the hub disc 62 by means of expansion pins 78 which are fitted into aligned axially extending bores in the disc member 58 slidable on the hub disc 62. The pins 78 will preferably have a press fit with the pin receiving bore in the hub disc 62 and a sliding fit with the bore in the header core disc 58 thus providing an axially expandable pin and sleeve bearing connection between said hub disc 62 and said slidable header core disc 58. A substantial number of these pins is provided at spaced intervals around the circumference of the hub disc in order to provide a strong support for the header core disc 58. The arrangement is such that the header core disc 58 is free to move axially as dictated by the expansion or contraction of the shell 18, but, on the other hand, is very rigidly supported against lateral or turning movement with relation to the sleeve hub 12.

FIG. 6 of the drawings illustrates another embodiment of the invention in a cooling roll, which comprises a drum having a peripheral surface in the form of a shell 82 which is continuously cooled by the circulation of a cooling medium in contact with the inner periphery of said shell. The drum 80 comprises generally two headers 84, 86 on which the shell 82 is mounted. The header 84 is formed on the end of a pivot shaft 88 which carries one end of the cooling roll assembly, the header 86 being similarly formed on the end of a hollow shaft 90 which provides pivotal support for the other end of the cooling roll assembly. The cooling roll assembly is also provided with an inner drum 92 having the end portions thereof narrowly spaced from the headers 84, 86 and the outer periphery thereof narrowly spaced from the inner periphery of the shell 82 so that a space is provided between the inner drum 92 and shell 82 for the circulation of cooling water. The inner drum 92 is secured at its left-hand end to a bearing block 94 rigidly fastened into a bore in the header 84 by screws 96. At its right-hand end the inner drum 92 is formed with a tubular extension 98 having a sliding fit with a sleeve bearing 100 provided in the header 86.

Coolant is introduced into the cooling roll through an inlet pipe 102 which extends through the hollow shaft 90 along the rotational axis of the cooling roll being supported at its left-hand end as shown in FIG. 6 in the bearing block 94 for the end of the inner drum 92. The coolant enters the coolant space provided interiorly of the shell 82 at the left-hand end of the drum assembly, flows to the right-hand end of the drum assembly and is drawn off through a passageway formed between the outside diameter of the pipe 102 and inside diameter of the hollow shaft 90.

In accordance with the invention the shell 82 is fitted over the peripheral faces of the two headers 84, 86 loosely to permit expansion and contraction of the rim with respect to the two headers, being connected thereto only by means of radial pins 104 which are arranged in two rows in staggered relation at spaced intervals about the periphery of the shell adjacent each end thereof. Each pin 104 is press fitted through the shell and extends radially inwardly into and has a sliding fit with a socket 106 which is held by a press fit in a radial bore in the periphery of the respective header. In the construction shown, there are twelve pairs of pins 104 mounted at equally spaced intervals about the periphery of the shell 82. The pins are further arranged in opposed relation at opposite sides of the shell on diameters angularly arranged with relation to one another and passing through the axis of the headers. It will be evident that each opposed pair of pins will provide a fixed support for the shell, including the rotational axis thereof, against movement in a direction transversely of the said diameter on which said pins are located while permitting expansion and contraction of the shell longitudinally of said diameter, so that the rotational axis of the shell is rigidly held at the point of intersection of all of said diameters in a position concentric with the hub axis. The arrangement is such that the shell 82 is at all times supported securely in an exactly centered position with relation to the rotational axis of the pivot shaft 88 and shaft 90 while at the same time it is permitted to expand and to contract freely in a radial direction independently of the headers 84, 86. In order to prevent leakage of the cooling medium through the relatively loose connections provided between the shell 82 and the headers 84, 86, the header 86 is provided adjacent its outer edge with a ring 108 which overlies the end of the shell 82. The header 84 is similarly provided with a ring 110 which overlies the opposite end of the shell 82. O-rings 112, 114 mounted in the inner faces of the rings 108, 110, respectively, prevent the escape of coolant past the ends of the outer shell 82. The shell 82 and headers 84, 86 of the cooling roll illustrated in FIG. 6 may be assembled as follows:

The sockets 106 are press fitted into bores in the peripheries of the two headers 84, 86 and the shell 82, similarly drilled to receive the pins 104, is then slid into position axially over the headers 84, 86. Each pin receiving hole in the shell 82 is now lined up with the associated socket 106, and a pin 104 is driven into position through the shell 82. Finally the rings 110, 108 are assembled and screwed to the outer faces of the headers 84, 86 in the positions shown.

With the construction shown, the outer shell 82 is permitted to expand and to contract radially with relation to the relatively thick-walled headers 84, 86 by means of the pin and socket connections above described, while at the same time the shell is at all times held firmly in its centered position with relation to the rotational axis of the cooling roll. Expansion and contraction of the outer shell 82 axially with relation to the inner drum 92 is permitted by the sliding fit provided between the bearing 100 formed within the right-hand header 84 and the tubular extension 98 of the drum 92.

The invention having been described what is claimed is:

1. A rotary drum for use in a rotary drum heat exchanger which comprises a shell having an external heat exchanging surface, a rotary hub, a plurality of disc headers mounted on the hub and spaced from one another along the length of the shell for supporting said shell, a series of expansion joints on which the shell is supported from said disc headers comprising opposed pairs of pin and sleeve bearing connections at opposite sides of each disc header along diameters intersecting the hub axis at a substantial angle to one another, the pins extending radially of the drum axis for movement relatively to said sleeve bearings only along said diameter, each opposed pair of pin and sleeve bearing connections on a said diameter providing a fixed support for said shell including the rotational axis thereof against movement in a direction transversely of said diameter, while permitting expansion and contraction of the shell longitudinally of said diameter, whereby the rotational axis of the shell is rigidly held at the intersection of said diameters concentric with the hub axis.

2. A rotary drum according to claim 1 in which each said expansion joint comprises a guide block having a bore extending radially of the shell axis secured to said shell, a guide block having a bore extending along the same radial line secured to said disc header, a guide pin extending through both of said bores, and means securing said guide pin within one of said bores in position for sliding engagement with the other said bore.

3. A rotary drum according to claim 1 in which a plurality of pin and sleeve bearing expansion joints are provided between each said disc header and said shell evenly spaced from one another about the periphery of said rotary drum and are paired in opposed relation at opposite ends of a plurality of pairs of perpendicularly crossing diameters.

4. A rotary drum according to claim 1 including a said disc header shiftable axially on said hub in accordance with the axial contraction and expansion of said shell, said axially shiftable header comprising a shell supporting disc member having radial pin and sleeve bearing expansion joints with said shell, a hub disc member fixed to said hub in radially overlapping relation to said shell supporting disc member, and a plurality of axially extending pin and sleeve bearing connections between the overlapping portions of said hub disc member and said shell supporting disc member spaced about the axis of said hub on which the said shell supporting disc member is keyed to turn with and is freely shiftable axially with relation to said hub disc member and hub.

References Cited by the Examiner UNITED STATES PATENTS 1,692,537 11/1928 Baumann.

1,692,538 11/1928 Baumann 253--69 1,873,743 8/ 1932 Doran.

2,563,692 8/1951 Ostertag 34-124 X 2,622,843 12/ 1952 Williams.

2,628,433 2/ 1953 Ostertag 34-124 2,817,908 12/ 1957 Hornbostel 341 10 3,060,592 10/1962 Ostertag 34124 3,169,050 2/1965 Kroon 34124 FOREIGN PATENTS 531,605 8/1931 Germany.

WILLIAM F. ODEA, Primary Examiner.

NORMAN YUDKOFF, Examiner.

J. SOFER, Assistant Examiner.

Claims (1)

1. A ROTARY DRUM FOR USE IN A ROTARY DRUM HEAT EXCHANGER WHICH COMPRISES A SHELL HAVING AN EXTERNAL HEAT EXCHANGING SURFACE, A ROTARY HUB, A PLURALITY OF DISC HEADERS MOUNTED ON THE HUB AND SPACED FROM ONE ANOTHER ALONG THE LENGTH OF THE SHELL FOR SUPPORTING SAID SHELL, A SERIES OF EXPANSION JOINTS ON WHICH THE SHELL IS SUPPORTED FROM SAID DISC HEADERS COMPRISING OPPOSED PAIRS OF PIN AND SLEEVE BEARING CONNECTIONS AT OPPOSITE SIDES OF EACH DISC HEADER ALONG DIAMETERS INTERSECTING THE HUB AXIS AT A SUBSTANTIAL ANGLE TO ONE ANOTHER, THE PINS EXTENDING RADIALLY OF THE DRUM AXIS FOR MOVEMENT RELATIVELY TO SAID SLEEVE BEARINGS ONLY ALONG SAID DIAMETER, EACH OPPOSED PAIR OF PIN AND SLEEVE BEARING CONNECTIONS ON A SAID DIAMETER PROVIDING A FIXED SUPPORT FOR SAID SHELL INCLUDING THE ROTATIONAL AXIS THEREOF AGAINST MOVEMENT IN A DIRECTION TRANSVERSELY OF SAID DIAMETER, WHILE PERMITTING EXPANSION AND CONTRACTION OF THE SHELL LONGITUDINALLY OF SAID DIAMETER, WHEREBY THE ROTATIONAL AXIS OF THE SHELL IS RIGIDLY HELD AT THE INTERSECTION OF SAID DIAMETERS CONCENTRIC WITH THE HUB AXIS.

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