US3367042A

US3367042A - Rotary heat exchanger with ribbed inner liner of higher thermal conductivity than outer shell

Info

Publication number: US3367042A
Application number: US569221A
Authority: US
Inventors: Jr Julian F Cox
Original assignee: Newport News Shipbuilding and Dry Dock Co
Current assignee: Newport News Shipbuilding and Dry Dock Co
Priority date: 1966-08-01
Filing date: 1966-08-01
Publication date: 1968-02-06
Anticipated expiration: 1985-02-06

Description

Feb. 6, 1968 J. F. cox, JR

ROTARY HEAT EXCHANGER WITH RIBBED INNER LINER OF HIGHER THERMAL CONDUCTIVITY THAN OUTER SHELL Filed Aug. 1, 1966 2 Sheets-Sheet l INVENTOR. mm A 602" JZ WMK m 147' f GENE V3 Ffib W8 J. F cox, JR 3 9 ROTARY HEAT EXCHANGER WITH RIBBED INNER LINER OF HIGHER THERMAL CONDUCTIVITY THAN OUTER SHELL Filed Aug. 1, 1966 2 Sheets-Sheet 2 m2 jiza I 92 p i, 7'00 92 g l \Q F \4 m/ v INVENTOR. Jzz/Zmz f 6'01 United States Patent 3,367,042 ROTARY HEAT EXCHANGER WITH RIBBED IN- NER LINER OF HIGHER THERMAL CONDUC- TlIVlTY THAN OUTER SHELL Julian F. Cox, In, Newport News, Va., assignor to Newport News Shipbuilding and Dry Dock Company, Newport News, Va., a corporation of Virginia Filed Aug. 1, 1966, Ser. No. 569,221 Claims. (Cl. 34124) ABSTRAQT OF THE DESCLOSURE A Yankee drier for drying a web of paper comprises a generally cylindrical shell closed at opposite ends thereof and journalled for rotation about its longitudinal axis. Means is provided for introducing steam into the drier and exhausting same therefrom. The shell includes an outer shell portion and a liner disposed inwardly thereof and in contact therewith, the liner being formed of a material having higher thermal conductivity than the outer shell portion. A plurality of spaced radially inwardly extending ribs extend continuously about the inner periphery of the liner in a circumferential direction.

The present invention relates to a new and novel rotary pressure Vessel, and more particularly to a Yankee drier or the like having a ribbed liner of high thermal conductance on the inner periphery thereof.

The present invention is particularly directed to Yankee driers employed for drying a web of paper which is run over the smooth outer surface of the Yankee drier shell to be smoothed, dried or glossed by the application of heat, and in some instances pressure.

Steam is admitted under pressure into the interior of the shell, and the shell is particularly designed to transfer the heat of condensation through the shell to the web being treated. Drying of paper and the like in web form requires high uniformity of heat transfer to the various portions of the shell to obtain the desired results.

It has been proposed in the prior art to provide integral ribs on the inner surface of the iron drier shell. The present invention represents an improvement over this type of arrangement.

In the present invention, a liner is provided on the inner surface of the outer cast iron drier shell, this liner having higher thermal conductivity than the cast iron portion of the shell. This liner is also provided with ribs of certain critical dimensions in order to provide optimum performance of the drier.

The provision of this liner serves to increase the rate of heat transfer through the shell, the liner preferably being made of a substance such as aluminum or copper and the like and being metallurgically bonded to the inside surface of the outer cast iron shell portion. With this arrangement, it has also been found that the rate of heat transfer is not affected by normal variations in condensate thickness or oscillation in condensate flow that occur above rimming speed of the drier.

The ribs formed on the liner limit the flow of condensate within the drier to a circumferential flow and ensure that no substantial longitudinal flow will occur.

Substantially uniform heat transfer to all portions of the outside surface of the shell is obtained, and at the same time the excellent strength and wear characteristics of the cast iron outer shell portion are maintained. The liner also serves to strengthen the shell somewhat, thereby adding to the structural rigidity of the construction.

The liner also serves to fill up small pores formed on the inner surface of the cast iron outer shell portion, thereby enhancing uniform heat transfer to a paper web pass- 3,367,042 Patented Feb. 6, 1968 ing over the shell, and further preventing leakage of steam through the outer shell portion. This eliminates the use of plugs in the cast iron drier shell.

The ribs are provided with a particular thickness and are spaced apart a particular distance in order to provide the desired results, the ribs having opposite side surfaces which extend substantially radially inwardly, the inner surfaces of the ribs being tapered to an apex or of crowned configuration. This apex or crown at the inner portion of each of the ribs aids in shedding condensate from the rib when the drier operates above rimming speed, thereby increasing the rate of heat transfer through the liner at such speeds.

The liner may be formed of various materials of high thermal conductivity such as aluminum or copper. These substances are desirable due to their availability and further their ability to adhere to a cast iron outer shell portion in a casting process.

An object of the present invention is to provide a new and novel Yankee drier or the like of such a construction as to provide an increased rate of heat transfer through the shell thereof.

Another object of the invention is the provision of a Yankee drier or the like wherein the rate of heat transfer is not affected by normal variations in condensate thickness or oscillations in the condensate flow that occur above rimming speeds of the drier.

A further object of the invention is to provide a Yankee drier which affords substantially uniform heat transfer to all portions of the outside surface of the shell thereof.

Yet another object of the invention is the provision of a Yankee drier or the like including supplementary means for preventing leakage of steam through the cast iron outer shell portion thereof, and wherein the overall strength of the construction is increased.

Other objects and many attendant advantages of the invention will become more apparent when considered in connection with the specification and accompanying drawings, wherein:

FIG. 1 is a longitudinal section through a Yankee drier according to the present invention;

FIG. 2 is an enlarged view of a portion of the structure shown in FIG. 1 illustrating certain details thereof; and

FIG. 3 is a view similar to FIG. 2 illustrating a modified form of the invention.

Referring now to the drawings wherein like reference characters designate corresponding parts throughout the several views, FIG. 1 illustrate a typical Yankee drier construction according to the present invention. A generally cylindrical shell is indicated generally by reference numeral 10 and includes an outer shell portion 12 formed of cast iron or similar material and having a smooth outer peripheral surface. A liner 14 formed preferably of aluminum or copper and the like is metallurgically bonded to the inner periphery of shell portion 12, this liner having a plurality of ribs 15 formed on the inner portion thereof, these ribs defined in more detail hereinafter.

A first head 16 is provided at one end of the shell, and a second head 18 is provided at the opposite end of the shell, these heads being suitably secured as by bolts 20 to the shell and forming closures for the opposite ends thereof.

A plate 24 is bolted to head 16 and includes a journal 28 which is hollow and receives an inlet tube 30 through which steam is introduced into the drier. Journal 28 is adapted to be rotatably supported in a suitable conventional manner. Inlet tube 30 is adapted to feed steam into the interior of a hollow tubular portion 32 integral with plate 24.

A plate 40 is secured by bolts 42 to head 18, plate 40 including an integral journal 44 which is hollow and which receives an outlet tube 46 for removing steam from the drier as hereinafter explained. Journal 44 is adapted to be suitably rotatably supported in a conventional manner. The outlet tube 46 is in communication with the hollow interior of a tubular portion 48 formed integral with plate 40.

The inner ends of

tubular portions

32 and 48 are provided with flanges 50 and 52. which extend radially outwardly thereof and which are bolted to one another by bolts 54. A plate 55 is sandwiched between flanges 50 and 52, and is secured in the operative position illustrated. Steam nozzles 56 and 58 are mounted within the outer ends of openings '60 and 62 respectively formed in plate 55, whereby steam introduced through the inlet tube passes through the tubular portion 32 and thence outwardly through openings 60 and 62 in steam nozzles 56 and 58 into the interior of the drier shell.

Means for removing condensate from the interior of the shell includes a support member 70 extending radially outwardly from the flange portion 52 and supporting a longitudinally extending hollow pipe 72 supported at brackets 74 and 76 at the opposite ends thereof, these brackets being mounted upon heads 16 and 18 respectively. A plurality of straws or tubes 78 extend from pipe 72 into the bottom of the grooves provided between adjacent ribs 15 formed on the liner 14, these tubes serving to pick up condensate in the grooves which is then carried to the pipe 72 and thence through a radially extending conduit 80 to the interior of the tubular portion 48.

A second support member 84 extends radially outwardly from flange 52 and supports a hollow pipe 86 at a position substantially diametrically opposite to the previously described pipe 72. Pipe 86 is supported at the opposite ends thereof by brackets 88 and 90 mounted on the heads 16 and 18 respectively. A plurality of straws or tubes 92 extend radially outwardly from pipe 86 into the bottom of the grooves formed between adjacent ones of the ribs 15 on the liner. Condensate received by tubes 92, which, of course, are open at the outer ends thereof, is directed to pipe 86 and thence through a radially inwardly extending conduit member 94 to the interior of the hollow tubular portion 48 whereupon the condensate may pass outwardly through the outlet tube 46.

Referring now to FIG. 2 of the drawings, an enlarged view of the lower portion of the shell shown in FIG. 1 is illustrated wherein certain critical dimensions of the various components are illustrated. As shown in this figure, the dimension A represents the thickness of the cast iron iron outer shell portion 12. The dimension B represents the width of an individual rib 15 in a direction extending substantially parallel with the longitudinal axis of the shell. The dimension C represents the space between facing side surfaces 100 of adjacent ones of said ribs, it being noted that these side surfaces extend substantially radially inwardly. The dimension D represents the height of the ribs, and the dimension E represents the root thickness of the liner.

The dimension A for all practical sizes of Yankee driers will lie within a range of about 0.25 inch to about 2.0 inches. The width of the rib B should lie within a range of bout 0.25 inch to about 1.50 inches, and with the configuration shown in FIG. 2, wherein no ribs are formed on the outer shell portion 12, the optimum value of the distance B is about 1.25 inches.

The distance C should lie within the range of about 0.25 inch to about 1.5 inches, and a spacing of about 0.5 inch is considered to be an optimum spacing.

The dimension D should lie within the range of about 0.25 inch to about 1.25 inches, and the dimension B should lie within the range of about 0.001 inch to about 0.125 inch.

It will be noted that the inner surface 102 of each of the ribs is tapered to an apex 104 these inner surfaces defining an angle x as seen in FIG. 2 with an adjacent side surface of the associated rib of approximately 15".

With the dimensions as set forth hereinabove, the arrangement has been found to provide optimum performance.

Referring now to FIG. 3, a modification is illustrated wherein the drier is in all respects similar to that previously described with the exception that the outer shell portion is provided with ribs. Similar parts will be given similar reference numerals primed, and it will be noted that the outer shell portion 12 is provided with spaced ribs which extend continuously around the outer periphery thereof and which extend radially inwardly from the shell. The liner is metallurgically bonded to the outer shell portion in this modification and is provided with a plurality of ribs 15 corresponding to the ribs 15 previously described.

The dimensions A, B, C, D and E correspond to the dimensions previously described. An additional dimension F indicates the height of the ribs 100 formed on the outer shell portion.

In this modification, the dimensions A and B should lie within the same ranges as discussed previously, but with this arrangement, the optimum value for dimension B is about 1.5 inches. The dimensions C, D. and E should also be within the same ranges as previously discussed with the optimum value of dimension C being the same. The dimension F should lie within the range of about 0.25 inch to about 1.25 inches, and the angle x may again be 15 in this modification.

It is apparent from the foregoing that there is provided according to the present invention a new and novel rotary pressure vessel such as a Yankee drier or the like having a construction which provides an increased rate of heat transfer through the shell thereof. The rate of heat transfer is not affected by normal variations in condensate thickness or oscillations in condensate flow that occur above rimming speeds of the drier. Substantially uniform heat transfer to all portions of the outside surface of the shell is afforded. The liner prevents leakage of steam through the cast iron outer shell portion, and further enhances the structural rigidity of the overall drier construction.

As this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, and since the scope of the invention is defined by the appended claims, all

changes that fall within the metes and bounds of the.

claims or that form their functional as well as conjointly cooperative equivalents are therefore intended to be embraced by those claims.

I claim:

1. A Yankee drier or the like comprising a generally cylindrical shell, a head at each end of said shell forming closures for opposite ends of the shell and including means for journalling the shell for rotation about its longitudinal axis, said shell including an outer shell portion, a liner disposed inwardly of said outer shell portion and in contact therewith, said liner being formed of a material having higher thermal conductivity than said outer shell portion, said liner including a plurality of spaced radially inwardly extending ribs, said ribs extending continuously about the inner periphery of said liner in a circumferential direction.

2. Apparatus as defined in claim 1, wherein said liner is metallurgically bonded to the inner periphery of said outer shell portion.

3. Apparatus as defined in claim 1, wherein the opposite side surfaces of each of said ribs on said liner extend substantially radially inwardly, and the inner surface of each of said ribs tapers inwardly to an apex.

4. Apparatus as defined in claim 1, wherein the space between the facing surfaces of adjacent ribs in a direction parallel with the longitudinal axis of said shell is within the range of about 0.25 inch to about 1.25 inches.

5. Apparatus as defined in claim 1, wherein the width of each of said ribs in a direction extending parallel with the longitudinal axis of said shell is within the range of about 0.25 inch to about 1.50 inches.

6. Apparatus as defined in claim 1, wherein the space between facing surface of adjacent ribs in a direction extending parallel with the longitudinal axis of said shell is within the range of about 0.25 inch to about 1.25 inches, and the width of said ribs in a direction extending parallel with the longitudinal axis of said shell is within the range of about 0.25 inch to about 1.50 inches.

7. Apparatus as defined in claim 1, wherein said outer shell portion defines a smooth outer peripheral surface, said outer shell portion being formed of cast iron, said liner being metallurgically bonded to the inner periphery of said outer shell portion, each of said ribs having opposite side surfaces extending radially inwardly and including an inner surface which is tapered to an apex, the space between the facing side surfaces of adjacent ribs in a direction extending substantially parallel with the longitudinal axis of said shell being within the range of about 0.25 inch to about 1.25 inches, and the width of each of said ribs in a direction extending substantially parallel with the longitudinal axis of said shell being within the range of about 0.25 inch to about 1.50 inches.

8. Apparatus as defined in claim 7, wherein said space is approximately 0.5 inch.

9. Apparatus as defined in claim 7, wherein said outer shell portion has radially inwardly directed ribs formed thereon, the radial dimension of said last-mentioned ribs being within the range of about 0.25 inch to about 1.25 inches.

10. Apparatus as defined in claim 9, wherein each of said ribs has a width of approximately 1.50 inches.

References Cited UNITED STATES PATENTS 1,763,629 6/1930 Hopkins 34110 X 2,141,377 12/1938 Chylinski 34119 X 2,259,024 10/1941 Cleveland 16589 3,241,251 3/1966 Justus et a1. 34-124 FOREIGN PATENTS 939,926 10/1963 Great Britain.

FREDERICK L. MATTESON, JR., Primary Examiner.

A. D. HERRMANN, Assistant Examiner.