US3318376A

US3318376A - Heat transfer fluid conduit wrapping for vessels

Info

Publication number: US3318376A
Application number: US559699A
Authority: US
Inventors: Vihl Bernhard
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-04-13
Filing date: 1966-04-13
Publication date: 1967-05-09
Anticipated expiration: 1984-05-09
Also published as: JPS5027231B1

Description

May 9, 1967 B. VIHL 3,31

HEAT TRANSFER FLUID CONDUIT WRAPPING FOR VESSELS Filed April 13, 1966 9 Sheets-Sheet l FIGQI FIG.2

INVENTOR.

BERNHARD VIHL ATT RNEYS B. vn-u. 3,318,376

HEAT TRANSFER FLUID CONDUIT WRAPPING FOR VESSELS May 9, 1967 9 Sheets-Sheet 2 Filed April 13, 1966 F|G.3v

INVENTOR.

BERNHARD VIHL TTORNEY B. VIHL May 9, 1967 3,318,376

HEAT TRANSFER FLUID counum WRAPPING FOR VESSELS Filed April 13, 1966 9 Sheets-Sheet 3 INVENTOR. BERNHARD VIHL %?m %L AT ORNEYS May 9, 1967 B. V'IHL I HEAT TRANSFER FLUID CONDUIT WRAPPING FOR VESSELS Filed April 13, 1966 9 Sheets-Sheet 4 Fl .IO

I INVENTOR. BERNHARD VIHL TORNEY ViHL May 9, 1967 HEAT TRANSFER FLUID CONDUIT WRAPPING FOR VESSELS Filed April 13, 1966 9 Sheets-Sheet 5 INVENTOR.

R. A m W W R m E T 7A May 9, 1967 Filed April 13, 1966 FIG. l5

B. vu-n. 3,318,376

HEAT TRANSFER FLUID CONDUIT WRAPPING FOR VESSELS 9 Sheets Shee'c 6 A ORNEYS y 9, 1967 B. VIHL Q 3,318,376

HEAT TRANSFER FLUID CONDUIT WRAPPING FOR VESSELS Filed April 15, 1966 9 Sheets-Sheet 7 FIGJB 19% F l6. I6

IN VENTOR BERNHARD VIHL ATTORNEYS B. ViHL.

May 9, 1967 HEAT TRANSFER FLUID CONDUIT WRAPPING FOR VESSELS Filed April 15, 1966 9 Sheets-Sheet 8 ON QE INVENTOR. BERNHARD VIHL TTORNEYS y 9, 1967 B. VIHL. 3,318,376

HEAT TRANSFER FLUID CONDUIT WRAPPING FOR VESSELS Filed April 13, 1966 9 Sheets-Sheet 9 I N VEN TOR. Bag/#19190 V/HL BY ;?42 W ,qrrowers United States Patent 3,318,376 HEAT TRANSFER FLUED CONDUIT WRAPPING FOR VESSELS Bernhard Vihl, 2 Glenwood St, Clifton, NJ. 07013 Filed Apr. 13, 1966, Ser. No. 559,699 30 Claims. (Cl. 165-469) This application is a continuation-in-part of application Ser. No. 453,561 filed in the United States Patent Office on Apr. 29, 1965, now abandoned, which in turn is a continuation-in-part of application Ser. No. 362,725 filed in the United States Patent Office on Apr. 27, 1964, now abandoned.

The present invention relates to heat transfer fluid conduit wrapping for vessels. It further relates to such conduit wrapping which may contain fluids under high pressure and be attached or affixed to a vessel for heat transfer, and it further relates to such conduit wrapping which may be affixed to a vessel for purposes of rapidly alternated heating and cooling of one or more zones, depending on the heating or cooling needs.

It is an object of the present invention to provide a heat transfer fluid conduit wrapping in the general form of a trough having outwardly curved flaring edges along its open side, this trough being preferably of a generally rounded cross sectional configuration.

It is another object of the present invention to provide a heat transfer fluid conduit wrapping which, with its longitudinal edges securely fastened or attached in fluidtight relation to the surface of a vessel as by welding, is transversely configured to flex without undue stressing through fairly rapid and extensive changes of temperature or pressure.

It is another object of the present invention to provide a vessel having a heat transfer fluid conduit wrapping of the kind described with adjacent turns of the wrapping welded along their longitudinal edges both to the surface of the vessel and to each other, the wrapping being afiixed to either the exterior or the interior surface of the vessel.

It is another object of the present invention to provide a vessel having a heat transfer fluid conduit wrapping of the kind described with adjacent turns of the wrapping welded along their longitudinal edges both to the surface of the vessel and to each other, the vessel itself being of either cylindrical or another shape, including an angular shape.

It is another object of the present invention to provide a vessel having a heat transfer fluid conduit wrapping of the kind described which, as wrapped, may contain fluids under high pressure while being substantially lighter than a vessel of the same capacity provided with heat transfer fluid jacketing of the traditional kind.

It is another object of the present invention to provide a vessel having a plurality of heat transfer fluid conduit wrappings of the kind described affixed to it in spaced, non-interwrapped array to permit selective zone heat transfer to or from the vessel.

It is another object of the present invention to provide a vessel having a plurality of heat transfer fluid conduit wrappings of the kind described affixed to it in interwrapped array to permit rapid changes of heat transfer conditions, for example, rapidly alternated conditions of heating and cooling, to be effected with respect to a given selected zone of the vessel.

It is another object of the present invention to provide a vessel having a plurality of heat transfer fluid conduit wrappings of the kind described affixed to it in superimposed array to permit rapid changes of heat transfer conditions, for example, rapidly alternated conditions of heating and cooling, to be effected with respect to a given selected zone of the vessel.

Patented May 9, 1967 These and other objects and advantages of the present invention as well as its nature and substance will be more clearly perceived and fully understood by referring to the following description and claims taken in connection with the accompanying drawings in which:

FIG. 1 represents a view in side elevation of a hemisperically bottomed vessel provided with heat transfer fluid conduit wrapping according to the present invention on both its side and bottom exterior surfaces, that on the side exterior surface being in two segments for selective zone heat transfer, and that on the bottom exterior surface being separate from that on the side surface for further selectivity;

FIG. 2 represents a bottom plan view of the vessel of FIG. 1;

FIG. 3 represents an enlarged fragmentary view in sectional elevation of the vessel of FIGS. 1 and 2 taken along line 3-3 in FIG. 2 looking in the direction of the arrows;

FIG. 4 represents an enlarged plan view of the bottom volute transition piece of the heat transfer fluid conduit wrapping shown in FIGS. 1 and 2;

FIG. 5 represents a view in side elevation of the transition piece of FIG. 4 taken along line 5-5 in FIG. 4 looking in the direction of the arrows;

FIG. 6 represents a transverse sectional view of the transition piece of FIG. 4 taken along line 6-6 in FIG. 4 looking in the direction of the arrows;

FIG. 7 represents a transverse sectional view of a fragment of the transition piece of FIG. 4 taken along line 77 in FIG. 4 looking in the direction of the arrows;

FIG. -8 represents a fragmentary side view, partly in section, of the vessel of FIGS. 1 and 2 particularly showing an alternate :bottom outlet construction;

FIG. 9 represents a fragmentary perspective view of a segment of heat transfer fluid conduit wrapping according to a preferred embodiment of the present invention;

FIG. 10 represents a sectional view of a vessel wall fragment with heat transfer fluid conduit wrapping upon it according to the present invention before actual attachment of the wrapping to the wall by welding;

FIG. 11 represents an enlarged view of a portion of FIG. 10 after attachment of the wrapping to the wall particularly showing a deposit of weld material whereby adjacent turns of wrapping are fastened to the vessel wall and also to each other;

FIG. 12 represents a fragmentary view in side elevation of a drum-bottomed vessel provided with helically-andspirally-wound transfer fluid conduit wrappings on its exterior surface according to the present invention with two segments of wrapping being interwrapped on each of a plurality of zones of the vessel wall;

FIG. 13 represents a fragmentary View in sectional elevation through the vessel of FIG. 12 taken on a diametral plane with the direction of view in FIG. 13 being the same as that in FIG. 12;

FIG. 14 represents a fragmentary view in sectional elevation of a vessel provided with heat transfer fluid conduit wrapping on its exterior surface according to the present invention with a first segment of wrapping aflixed directly to the vessel Wall and a second segment superimposed on the first segment;

FIG. 15 represents a fragmentary view in sectional elevation of a vessel provided with heat transfer fluid conduit wrapping on its exterior surface according to the present invention with a first segment of wrapping aflixed directly to the vessel wall, a second segment superimposed on the first segment, and a third segment superimposed on the second segment;

FIG. 16 represents a fragmentary view in sectional elevation taken along line 1616 in FIG. 17, looking in the direction of the arrows, of a cylindrical, drum- 'of vessel 22 according to FIGS. 1-3.

4-7 the transition piece is represented as it might be made duit defined within this wrapping is provided for theat-- tachment of a pipe conductor;

FIG. 19 represents an end view of the closing means shown in FIG. 18 taken along line 19-19 therein looking in the direction of the arrows;

FIG. 20 represents a fragmentary view in sectional elevation taken along line 20--20 in FIG. 21, looking in the direction of the arrows, of a rectangular, flat-bottomed vessel having heat transfer fluid conduit wrappings affixed to its'side and bottom interior surfaces;

FIG. 21 represents a sectional plan view of the vessel of FIG. 20 taken along line 2121 therein looking in the direction of the arrows;

FIG. 22 represents a perspective view of a return bend heat transfer conduit wrapping according to thepresent invention before it is attached to a vessel; and

FIG. 23 represents a perspective view of a vessel to which return bend heat transfer conduit wrappings of the type illustrated in FIG. 22 and other heat transfer conduit wrappings according to the present invention are attached.

Referring now to the drawings in detail, especially FIGS. 1-7 thereof, 20 designates the overall assembly of a vessel such as a chemical blending retort provided with helically and spirally wound heat transfer fluid conduit wrappings according to the present invention. The vessel itself is designated 22, and is characterized by a drum-shaped head and a hemispherically-shaped bottom. Between its top and bottom ends it is of essentially straight cylindrical configuration. The top of the vessel is provided with various fittings to serve as connections for influent fluids, pressure gauges, thermometers, stirring devices, etc. These fittings, which are shown for purposes of example only, do not by themselves constitute any part of the present invention. At its lower end, vessel 22 is provided with a bottom outlet fitting 23 which is discussed in'sorne detail hereinafter in connection'with a form of the present invention slightly alternate from that shown in FIGS. l-7.

Aflixed fluid-tightly to the exterior surface of the central cylindrical wall portion of vessel 22 are two helically Wound heat transfer

fluid conduit wrappings

24 and 26. A third wrapping 28 of mixed helical and spiral configuration which terminates in a primary spirally wound volute transition piece 30 at its lower end. is atfixed to the exterior surface of the vessels hemispherical bottom. Assuming that these wrappings define conduits through which a condensableheating fluid, for example, steam, is to be carried, the inlet connection of each conduit so defined would be at the conduits upper end and the outlet connection at its lower end so that any liquid water formed through the condensation of steam would be easily drained away. Accordingly, wrapping segment 24 is pro- 'vided with inlet. fitting 32 and outlet fitting 34; Wrapping segment 26 is provided with inlet fitting 36 and outlet fitting 38, and wrappingsegment 28 is provided with inlet fitting and outlet fitting 42.

Volute transition piece 30 as shown in FIGS. '4-7 is not completely shaped to fit the hemispherical bottom Rather in FIGS.

as a standard trough-like piece having its open side spirallywound in a single plane and being amenable to further shaping to suit the requirements of 'a particular installation. As is shown in FIGS. 4 and 7, transition and the wrappings aflixed to it due to changes in tempiece 30 has an arcuate length of about 270 and a transverse cross sectional area which enlarges continuously from the end having outlet fitting 42 to the end which is joined to wrapping segment 28. The enlargement of the cross sectional configuration facilitates the draining to outlet fitting 42 of any liquid in Wrapping segment 28 or transition piece 30, for example, water formed by condensation of steam upon the walls of transistion piece 30 or any of the wrapping segments such as wrapping segment 28 located on the vessel above transition piece 30 and feeding into it. The larger of the two ends of transition piece 30' is connected to wrapping segment 28 in a fluid-tight manner, preferably by welding, and its outwardly curved flaring edge portions are connected to the surface of vessel 20, also preferably by welding. In affixing it to a vessel, transition piece 30 is shaped to correspond to the shape of the vessel surface to which it is attached, which in the embodiment shown in FIG. 3, is substantially hemispherical.

It is to be noted that wrapping segments 24, 25- and 28 are arranged serially along the surface of vessel 22 from top to bottom. Thus, if steam be supplied to the conduit defined by wrapping segment 24 alone, only a particularly selected zone of the vessel will be heated. By supplying steam to only one or some of the conduits defined by the several wrappings, therefore, selective zone control of heat applied to the vessel may be achieved. Whether one, some, or all of the conduits defined by the Wrappings of this invention are supplied with steam or some other heating fluid will, of course, depend upon the amount of heating or nature of the reaction desired to be carried out within the vessel 22.

Although for purposes of example and description it has been assumed that steam is to be used in the conduits defined by wrapping

segments

24, 26 and 28, it will be apparent. to those skilled in the art that these conduits may just as well be used to carry heating fluids other than steam, for example, hot Water. Similarly, if the effect desired within the vessel 22 be one of cooling rather than heating, the conduits defined by the wrappings afl'ixed to the vessels exterior wall surfaces may carry cold water or some other refrigerant with a selectively of zone heat transfer or temperature control which is as flexible as that aforedescribed in the case of heating steam. Further, where either a non-condensing or a non-vaporizing fluid is to be circulated through the conduits, whether this fluid be one for heating or for cooling of the vessels contents, it may be circulated upwardly through the wrapping-defined conduits rather than downwardly through them, if desired. In this circumstance,

fittings

34, 38, and 42 would become inlet fittings, and

fittings

32, 36, and 40 would become outlet fittings. An insulated material appropriate for heat or cold as required will be applied to the overall assembly 20 of the vessel and its wrappings.

The preferred mode of attachment or aifixation of wrappings .24, 26, and 28 to the exterior wall surfaces of vessel 22 is by welding, and it is a feature of the present invention that adjacent wrapping turns are wound onto the vessel surfaces sufficiently close to each other that a single deposit of weld material will be effective to fasten adjacent turns both to the vessel wall and to each other. This provides an economy of welding with respect to both material deposited and time required for the overall operation of attaching the wrapping segments.

This mode of attachment of wrapping segments to vessel wall surfaces will be particularly appreciated upon consideration of FIG. 3. In this figure, it may be seen that the successive turns of heat transfer fluid conduit wrapping in any particular segment of this wrapping are arrayed in a more or less bellows-like formation. Thus, when there are dimensional changes in vessel 22 perature, even fairly wide and rapid temperature changes,

these wrappings can flex transversely as Well as tQI- 'sionally in a spring-like or bellows-like manner Without the setting up in them of any particularly high stresses which might serve to fracture the wrappings or break them loose from their joints to each other or to the vessel wall.

It will be seen further upon consideration of FIG. 3 that there are no continuous areas of either vessel wall surface or heat transfer fluid conduit wrapping surface having relatively large dimensions of both length and breadth which can be exposed to high pressures of heat transfer fluid, for example, high pressures of heating steam. This is in contrast to the construction of heated vessels known to the prior art where jackets rather than conduit wrappings are applied to vessel walls, and large panel areas of both jacket and vessel material are exposed to fluid pressures. In this prior art construction, therefore, wall thicknesses of both the vessels and their jackets must be rather large where steam pressures or other fluid pressures of any significant magnitude are to be sustained. Since it does not have large panel areas exposed to fluid pressure as in the case of prior art constructions of the jacketed type, employment of the heat transfer fluid conduit wrapping of the present invention allows for a reduction in thickness of metal parts exposed to heat transfer fluid at any particular pressure relative to such jacketed type constructions, for example, and so results in a substantial economy of construction with respect to the weight of metal required.

Another advantage of the present invention which derives directly from the one just described is that with vessel walls of reduced thickness, and correspondingly reduced heat capacity and resistance to heat flow, the time needed to effect a significant temperature change in the contents of a vessel when switching from a heating to a cooling fluid in thesurrounding conduit is substantially reduced. Thus, better control of reactions going on within the vessel is achieved.

Referring next to FIG. 8, it will be seen that a special annular collar or shell 44 has been applied around the neck of bottom outlet fitting 23 of vessel 22. This collar is welded or otherwise fluid-tightly attached around the fitting neck on its, the collars, inner periphery, and it makes a similar fluid-tight joint with heat transfer fluid conduit wrapping 28 or volute transition piece 30 thereof, around its outer periphery. The conduit defined by wrapping 28 including volute transition piece 30 instead of discharging through fitting 4-2, as shown in FIG. 1, has been provided with a series of drain ports 46 opening into the space bounded by the lowermost turn of the wrapping, the neck of outlet fitting 23, and the inner surface of collar 44. Thus, steam or condensate descending within wrapping segment 28 must come into contact with the neck of the bottom outlet fitting of vessel 22 before it is finally discharged through an outlet fitting 48 set in collar 44. By this arrangement the heating effect, or a cooling effect if such be desired, available from fluid circulated through the conduits defined by wrapping segment 28 and volute transition piece 30 is carried all the way down to and around the bottom outlet fitting of vessel 22 to give thermal control of the vessels contents right down to their very point of discharge from the vessel.

Referring next to FIG. 9, a perspective end view is given of a segment of heat transfer fluid conduit wrapping 50 according to a preferred embodiment of this invention which may be considered as representative of the transverse elemental configurations of wrapping

segments

24, 26, and 28 hereinbefore illustrated and described, wrapping 50 being shown in FIG. 9 separated from a vessel wall. Segment 50 has a generally rounded transverse central portion 52 which terminates in outwardly curved

flaring edge portions

54 and 56. The outward flare of these edge portions is significant for purposes of the present invention. The edge portions should not, however, be turned out absolutely flat or straight upon at least one third of the radius of curvature R 6 their attachment to a vessel Wall, but should have tangent lines or planes at an angle a of between 10 and 25, with respect to a base plane extending between them as illustrated in FIG. 9. It has been found that it is desirable that there be an angle of between 10 and 25 between a base plane extending between the edges of the wrapping and a tangential plane along the line of contact between each edge portion of the wrapping and the surface of the vessel to which the wrapping is attached to get appropriate springing action of adjacent turns of wrapping and to ensure that

edge portions

54 and 56 make only lines of contact with the vessel wall, rather than planar contact. It is believed that the angulation of the edge portions and the fact that only lines of contact are made with the vessel wall mitigate against the concentration of stresses in the weld and permits the wrapping to carry more of the stresses, the wrapping expanding and contracting in a bellow-like fashion with changes of temperature and pressure. It has been found that the angle a is preferably about 10 to 15.

For purposes of illustrating desirable proportions and not of applying any limiting dimensions, segment 50 may be considered as having a thickness of A; inch, a base width W between longitudinal edges of between four and five inches and a height H from its base plane to the crown of its central rounded section 52 of about one and a half inches. In such an embodiment, the inside radius R of the central round section of segment 50 may be about one and a half inches and the inside radii R of its outwardly curved flaring edges about a half inch. As in this illustrative embodiment, it has been found desirable that the radius of curvature R of the flared edge portions of the wrapping be about one third of the radius of curvature R of the central portion and that the thickness of the material of the wrapping be This relative proportioning of radii R and R and of the thickness of the wrapping material has been found to be preferable from the viewpoint of obtaining appropriate springing action and strength of the wrapping with changes in temperature. It has been found that a wrapping having a base width W, height H, and radii of curvature R and R as recited above and a material thicknes of about 0.125 inch, will sustain an internal fluid pressure of 3,000 pounds per square inch (p.s.i.) when attached to a three-eighths inch thick vessel wall. If it be assumed that a safety factor of 5:1 is desired, the illustrated embodiment of this invention can be used with a working pressure of 600 p.s.i., which far exceeds the working pressure and safety factor possible with prior art wrappings having corresponding thicknesses of materials. It is believed that the fact that a high working pressure can be achieved with the wrapping of this invention is due at least in part to the configuration of the outwardly curved flaring edge portions of the wrapping, and that the configuration described herein mitigates stresses in the welds due to expansion and contraction of the wrapping with changes in temperature and pressure by the wrappings ability to expand and contract in a bellows-like fashion.

Other transverse configurations of wrapping segments, for example, triangular configurations, may be employed within the scope of this invention, but as hereinbefore stated the rounded configuration shown in FIG. 9 represents a preferred embodiment. Whatever embodiment is used, it is important in any case for purposes of this invention that the wrapping segments longitudinal edges be extended outwardly curved so that when adjacent turns of wrapping are together for attachment to the wall of the vessel as by welding, the region for deposit of the weld metal, that is, the small region left between edges of adjacent turns, will be far enough away from the central sections of the wrapping turns that there will be no tendency of the welding flame or are to be diverted toward the central sections. Thus, while being sufficiently close to each-other that a single deposit of weld material may be used to simultaneously bond adjacent turns both to each other and to the vessel wall, the turns are preferably also sufliciently spaced apart to prevent diversion of the weld flame or are toward the central portion of the wrapping and also to forstall splattering or other depositing of weld material onto the central portion. It has been found that wrapping turns that are not spaced apart cannot be readily or satisfactorily welded.

Referring next to FIG. 10, wrapping segment 50 is shown applied to a portion of a vessel wall 58 prior to actual attachment to this wall by welding. Wall portion 58 may be considered similar to the straight or vertical cylindrical section or portion of the wall of vessel, 22 in FIG. 1. In FIG. it will be seen that because of the outwardly curved flare of the edges cfadjaccnt wrapping turns there is ample room for weld' deposit to anchor the turns to the surface of wall portion 58 and to each other'only along their edges without any weld material being spattered or otherwise deposited onto the central rounded section 52 of the .wrapping turns.

Referring next to FIG. 11, the'mode of attachment adjacent turns of segment 50 to each other and to the surface ,ofwallportion 58 by means of a single deposit of weld material-60 is shown clearly. It Willbenoted particularly that; because of the aforedescribed preferable 10"15 angulation of the edge portions of the wrapping turns these portions do not come down flat against thesurface of base wall 58 ,when the edge portionsv are welded to the wall, but'insteadmake lines of contact with wall'58. They thus have at least some possibility lines of contact with'the wall instead of planar contact,

' it has been found that'thepossibility of the weld cracking with relatively high fluid pressures and the wrapping being separated from the wall is mitigated. It is believed that this maybe due to the fact that, with only a line.

of contact, there will not be any spacing between the 1 vessel wall and parallelly disposed edgeportions of thewrappingin which the pressure of the fluid could exert oppositely directed separating forces. ,It is believed that due to the aforedescribedangulation of the edge portions Referred next to FIGS. 12 and 13, 62 designates the overall assembly of another vessel such as a chemical blending retort provided with heat transfer fluid conduit wrapping according to the present invention. The vessel itself, shown fragmentari-ly, is designated 64, and is characterized by a drum-shaped bottom above which there is an essentially straight cylindrical section. Aflixed to the exterior surface of the cylindrical wall portion of vessel 64 are four heat transfer fluid conduit wrappings or

Wrapping segments

66, 68, 70 and 72. Two more wrappings or wrapping segments 74 and 76 are affixed to the exterior surface of the vessels druam shaped bottom. The conduits defined by

wrappings

66, 68, 70', 72, 74 and 76 have upper

fluid connection fittings

78, 80, 82, 84, 86 and 88 respectively and the lower

fluid connection fittings

90, 92, 94, 96, 98 and 100 respectively. There is a bottom outlet fitting 102 on the vessel itself.

It is to be noted particularly that the several heat transfer fluid conduit wrappings are interwrapped in pairs on successive zones of the vessel wall surface. Specifically, wrappings 66 and 68 are interwrapped on one zone;

wrappings

70 and 72 are interwrapped on another zone, and wrapping-s 74 and 76 are interwrapped on still another zone. Whether the upper fluid connection fittings on the conduits defined by these several wrappings are to be regarded as inlet fittings and the lower fittings thereon as outlet fittings or vice versa or some of each as one and some of each as theother will depend upon the thermal treatment tobe given to the contents of vessel 64 in the carrying out of any particular reaction or process.

For purposes of a simple example, it may be assumed that the contents of vessel 64- are to be highly heated and then rapidly chilled. The conduits defined by wrappings 66, 72 and. 74. are to carry steam and those defined by

wrappings

68, 70, and 76 are to carry a refrigerant. Upper

fluid connection fittings

78, 80, 82, 84, 86 and 88 are -to be used as inlet fittings, and lower

fluid connection fittings

90, 92, 94, 96, 98 and 100 are to be used as outlet fittings. Initially, steam is supplied to the conduits shownin FIG." 11, any such force that may occur is at least in part directed into the spring-like wrapping rather than concentrated at the weld; The single deposit of weld material 60 may, it is understood, be generated in the aggregate in either one pass or a plurality of passes of a welding rod. Among the factors determining the number'of passes actually required willbe the size of welding rod and .the thickness of material of wrapping segment;

In the actual practice of the present invention, it has been" found that the edge-to-edge spacing of adjacent turns or runs of wrapping segment 50 should be varied tion of such metals:

Vessel Wall Wrapping Material Thickness, in.

Spacing between Ad- Thickness jaceut Edges of Wrapping Turns, in.

$6 13 ga. (.092 in.) is an.-- 12 ga (.108 in.) its 1 "do M 11 ga. (.125 in.) 54

defined by

wrappings

66, 72 and 74, and those defined by

wrappings

68, 70 and 76 are left idle. After the required processing time at high temperature has elapsed, the steam is shut off and essentially simultaneously a flow of refrigerant is started through the conduits defined by

wrappings

68, 70 and 76. Thus the chilling treatment is'capable of being started even before the residual steam and condensate in the conduits defined by wrappings 66,

v

72 and 74 has been drained away.

It will be apparent to those skilled in the art that much more complicated thermal treatments of the; contents of vessel64 could be devised on a selective zone basis which would be capable of being carried out rapidly and with precision of timing of various particular thermal effects because of the high degree of flexibility of fluid flow arrangements provided by the distribution of

wrappings

66, 68, 70, 72, 74 and 76 according to the present invention.

Referring next to FIG. 14, 104designates the overall assembly of another vessel such as a chemical blending retort provided with heat transfer fluid conduit wrapping accordingly to the present invention. The vessel itself, shown fragmentarily, is designated 106. Aifixed by welding to the exterior surface of a cylindrical wall portion of the vessel is a first heat transfer fluid conduit wrapping segment 108. Superimposed upon and aflixed by welding to wrapping segment 108 is a second heat transfer fluid conduit wrapping segment 110. The deposit of weld material whereby wrapping segment 110 is aflixed to wrapping segment108 runs substantially along the crown of the latter segment.

A first or inner heat transfer fluid conduit 112 is defined between wrapping segment 108 and the exterior surface of vessel 106. A second or outer heat transfer fluid conduit 114 is defined between wrapping

segments

110 and 108. Appropriate inlet and outlet fittings, not shown, are provided on and in wrapping

segments

108 and 110 so that heat transfer fluids may be admitted into and discharged from the two conduitsl Inner conduit 112 may, for example, be used for circulation of a heating fluid while outer conduit 114 is reversed for circulation of a cooling fluid.

Assuming that the contents of vessel 106 are to be initially heated and subsequently cooled, a liquid heating fluid such as oil or a salt solution is first circulated through inner conduit 112. During the heating cycle or period there is no circulation of any fluid through outer conduit 114. At the end of the heating period, circulation of the heating medium is terminated but conduit 112 is not drained; that is, it is left full of stagnant fluid. Circulation of cooling fluid through outer conduit 114 is then started. During the cooling cycle or period the stagnant fluid within inner conduit 112 as well as the material of wrapping segment 108 and that of vessel 106 acts as a heat transfer medium. The advantage of the arrangement shown in FIG. 14 is that the entire outer surface of the vessel 106 in way of wrapping segment 108 is available as a heat transfer surface during both the heating period and the cooling period without any loss of time between the end of circulation of one heat transfer fluid and the beginning of circulation of another.

Referring next to FIG. 15, 116 designates the overall assembly of another vessel such as a chemical blending retort provided with heat transfer fluid conduit wrapping according to the present invention. The vessel itself, shown fragmentarily, is designated 118. Afiixed by welding to the exterior surface of a cylindrical wall portion of the vessel is a first heat transfer fluid conduit wrapping segment 120. Superimposed upon and aflixed by welding to wrapping segment 120 is a second heat transfer fluid conduit wrapping segment 122. Superimposed upon and aifixed by welding to wrapping segment 122 is a third heat transfer fluid conduit wrapping segment 124. The deposits of weld material whereby wrapping segment 122 is aflixed to wrapping segment 120 and wrapping segment 124 is aflixed to wrapping segment 122 run substantially along the crowns of wrapping

segments

120 and 122 respectively.

A first or inside heat transfer fluid conduit 126 is defined between wrapping segment 120 and the exterior surface of vessel 118. A second or intermediate heat transfer fluid conduit 128 is defined between wrapping

segments

122 and 120. A third or outside heat transfer fluid conduit 130 is defined between wrapping

segments

124 and 122. Appropriate inlet and outlet fittings, not shown, are provided on and in wrapping

segments

120, 122 and 124 so that heat transfer fluids may be admitted into and discharged from the three conduits. Outside conduit 130 may, for example, be used for circulation of a warming fluid, while intermediate conduit 128 is used for circulation of a medium heating fluid, and inside conduit 126 is used for circulation of a high heating fluid. During circulation of fluid through conduit 130,

conduits

128 and 126 would both be filled with fluids, preferably liquid fluids, to act as heat transfer media, while during circulation of fluid through conduit 128 there would be a heat transfer fluid filling conduit 126.

The heat transfer fluid conduit wrapping arrangement of FIG. is an extension of that of FIG. 14, and can, of course, itself be extended to provide four or any greater number of superimposed heat transfer fluid conduits on a single vessel as may be desired. It will be apparent to those skilled in the art that with a plurality of such conduits available, a wide and highly flexible variety of thermal treatments may be imposed upon the contents of the wrapped vessel.

Referring next to FIGS. 16, 17, 18 and 19, 132 designates the overall assembly of another vessel such as a chemical blending retort provided with heat transfer fluid conduit wrapping according to the present invention. The vessel itself, shown fragmentarily, is designated 134, and is characterized by an essentially drum shaped bottom 10 above which there is an essentially straight cylindrical section. Aflixed to the interior surface of the cylindrical section of vessel 134 is a heat transfer fluid conduit. wrapping or wrapping segment 136. Another wrapping segment 138 is aflixed to the interior surface of the vessels drum shaped bottom.

The conduit defined by wrapping segment 136 is partly closed at its upper end by a specially shaped plate 140 which is welded all around at its edges to the interior wall surface of vessel 134 and the transverse periphery of the wrapping segment. This conduit is fully closed at its lower end by a suitable welded plate, not shown, or by being flattened down and welded to the vessels interior wall surface. At its upper end, wrapping segment 136 is cut on a bias as shown particularly in FIG. 18, with the attendant effect of enlarging the surface area of plate 140 at least somewhat over what it would be if the wrapping segment were cut off square. This allows the plate to be characterized by a fairly large hole or access opening 142 to which a pipe conductor 144, which does not penetrate the vessel wall, may be connectedfor the supplying of fluid to or the carrying of fluid away from the conduit defined by wrapping segment 136. This conduit has a lower fluid connection fitting 146 which penetrates the wall of the cylindrical section of vessel 134.

The spirally shaped conduit defined by heat transfer fluid conduit wrapping segment 138 has upper and lower or outer and inner

fluid connection fittings

148 and 150 which penetrate the drum shaped bottom of vessel 134. The ends of the conduit defined by this wrapping segment are fully closed by suitable means such as welded plate 152. There is a bottom outlet fitting 154 on the vessel itself. It is to be noted in the embodiment of the pres ent invention shown in FIGS. 16 and 17 that with the heat transfer fluid

conduit wrapping segments

136 and 138 applied to the interior surface of vessel 134 with consequent transfer of heat to or from the vessels contents through the wrapping segments in the first instance, a heat transfer surface areafor these contents is provided which is at least somewhat greater than the interior wall surface area of the vessel itself because of the undulating contour of wrapping

segments

136 and 138 as installed.

Referring to FIGS. 20 and 21, 156 designates the overall assembly of another vessel such as a chemical blending retort provided with heat transfer fluid conduit wrapping according to the present invention. The vessel itself, shown fragmentarily, is designated 15%, and is characterized by an essentially flat bottom above which there is an essentially rectangular section. Affixed to the interior surface of the upper, rectangular section of vessel 158 is a heat transfer fluid conduit wrapping or wrapping segment 160. Another wrapping segment 162 is affixed to the interior surface of the vessels flat bottom. Each of these overall segments comprises a plurality of individual segments mitred to each other at their ends as well as being welded to each other and to the interior surfaces of vessel 158 along their longitudinal edges.

The conduits defined by wrapping segments 160 and 162 are each closed at both ends by appropriate welded plates. The conduit defined by wrapping segment 160 has upper and lower fluid connection fittings 164 and 166 which penetrate the wall of the upper, rectangular section of vessel 158. The conduit defined by wrapping segment 162 has outer and inner fluid connection fittings 168 and 170 which penertate the flat bottom of vessel 158. No bottom outlet fitting is provided on vessel v158 as shown, the contents of the vessel being removed, when desired, by suitable suction or pumping lines. Similar to the case of the embodiment of the present invention shown in FIGS 16 and 17, the heat transfer surface area for the contents of assembled vessel 156 is somewhat greater than the interior wall surface area of the basic vessel 158 itself on account of the undulating contour of its internal heat transfer fluid conduit wrapping.

Referring finally to FIGS. 22 and 23, these figures illustrate another embodiment of this invention in which a return bend heat transfer fluid conduit wrapping 200 having a substantially U-shaped longitudinal axis is employed. The return bend wrapping 200-is characterized by a cross-section perpendicular to its longitudinal axis which is in the form of a trough with outwardly curved flaring edge portions 202 and a rounded central portion 204. As is shown in FIG. 22, the adjacent edge portions of the return bend wrapping are spaced apart and adapted to be bonded to each other and to a surface of a vessel,

such as vessel 206 of FIG. 23, by a single deposit of weld material in the space between the edge portions. The radius of curvature R of the outwardly curved flaring edge portions is preferably one third of the radius of curvature R of the rounded central portion of the wrapping, and the thickness 'of the material of the wrapping is preferably at least one third of the radius of curvature R There is an'angle a of between .and 25, but preferably about 10 to between a base plane 208 extending between the edges of wrapping 200 and a tangential'plane along the line of contact of the edge portion 202 and the base plane 208, and as was described above with reference to FIGS. 9 and 11 and another embodiment of thisinvention, when they are welded to the wall of a vessel edge portions 202 preferably make only lines of contact with the vessel wall, rather than planar contact. The angulation and proportioning of edge portions 202, and the fact that only lines-of contact are made with the vessel wall, permit the wrapping 200 to expand and contract freely and also mitigate against the concentration of stresses at the weld. Further, since adjacent wrapping turns are close together with only a weld between them,.the fluid in the heat transfer fluid conduit makes maximum contact with the surface of the vessel to which it is attached. This facilitates the inducing of rapid changes of temperature in the vessels contents as almost, the entire wrapped portion of the vessel wall is heated or cooled;

The return bend wrapping 200,has an inlet opening 210 atone of its ends and an outlet opening 212 at its other end, andvwhen the wrapping is attached to vessel 206, it is connected in a fluid-tight relationship as by 'welding to adjacent ends of adjacent parallel conduit portions 214, thereby providing a continuous fluid passage way through the adjacent parallel conduit portions 214 and thereturn bend wr-appings 200.

Referring nowmore specifically to FIG. 23, vessel 206, constituting part of an overall vessel assembly 207,'has a substantially rectangular upper section 216, and a lower section 218 with a curved surface. On the surface of the upper section" of vessel 206 are a series of parallel wrapinclined rather than horizontal.

Wrappings corresponding to the wrapping just .described with reference to the upper section of the, vessel 206 also appear on other surfaces of the'vessel. It is to be noted that the wrappings maybe interconnected so asto form a single continuous passageway for fluid by connecting suitable auxiliary conduits to the inlet and.

outlet fittings, or they may be interconnected to form an upper zone of heating or cooling, and a lower zone which might be at a diflerent temperature. It is also to be noted that adjacent edge portions of the various wrapping segments are spaced apart sufficiently to forestall diversion of the welding flame or are toward the central portion of the: wrappings and also to avoid splattering or other depositing of weld material onto the central section, but, at

' the'same time, adjacent edge portions of the, wrapping segments are sufficiently close together that a single deposit of weld material may be used to simultaneously fasten adjacent turns or runs both to each other and also to the vessel wall.

It is thus seen that by practicing this invention in the manners described it is possible to obtain a vessel having a heat transfer fluid conduit wrapping attached to a surface thereof, the Wrapping turns having adjacent continuous edge portions which are spaced apart from one another and each having a transverse cross-section which is in the form of a trough with outwardly curved flaring edge portions making lines of contact with the surface of the vessel, and in which the wrapping is further characterized in that adjacent edge portions of the wrapping turns may be simultaneously bonded to each other and to the surface of the vessel at said lines of contact by a single deposit of weld material in the space between the edge portions.

Further, although not specifically illustrated as an embodiment of the present invention, it will be clear to those skilled in the art on the basis of what has been shown and described that heat transfer fluid conduit wrapping of the kind within the contemplation of this invention could be applied to the exterior as well as to the interior surfaces of a rectangular, flat bottomed vessel such as vessel 158. It will also be clear to those skilled in the art that the cross-section of vessels about or upon which heat transfer fluid conduit wrapping of the kind within the contemplation of this invention may be applied, either exteriorly or interiorly, is not limited to one which is round or one which is rectangular. It may also be any reasonable one other than a round one or a rectangular one such as one which is, for example, elliptical, oval, octagonal, hexagonal, pentagonal, or triangular.

Protection by Letters Patent of the present invention in all its aspects as the same are set forth in the appended claims is sought to the broadest extent that the prior art allows.

What-is claimed is:

1. A heat transfer fluid conduit wrapping for vessels adapted for attachment to a surface of a vessel by welding, the transverse cross-section of the wrapping being in the form of a trough having arounded central portion and outwardly curved flaring edge portions, and the radius of curvature of each of said edge portions being about one third of the radius of curvature of said central portion.

2. A heat transfer fluid conduit wrapping for vessels according to claim 1, the thickness of the material of said wrapping being at least one third of the radius of curvature of each of its edge portions.

3. A heat transfer fluid conduit wrapping for vessels adapted for attachment to a surface of a vessel by welding, the transverse cross-section of the wrapping being in the for-m'of a trough with outwardly curved flaring edge portions, in which said wrapping is further characterized by there being an angle of between 10 and 25 between a base plane extending between the edges of the wrapping and a tangential plane along the line of contact between each said edge portion and the surface of the vessel.

4. A heat transfer fluid conduit wrapping for vessels adapted for attachment to a surface of a vessel by welding, the transverse cross-section of the wrapping being in the form of a trough with outwardly curved flaring edge portions, in which said wrapping is further characterized by there being an angle of about 10 between a base plane extending between the edges of the wrapping and tangential plane along the line of contact between each said edge portion and the surface of the vessel.

5. A heat transfer fluid conduit wrapping for vessels adapted for attachment to a surface, of a vessel by welding, this wrapping being in the form of a spirally-wound trough characterized 'by (1) a generally rounded transverse cross sectional configuration, 2) outwardly curved flaring edge portions along its open side, (3) one end and another end,-

1 3 and (4) a transverse cross sectional area which enlarges continuously from said one end to said other end, the open side of said trough facing in a direction generally normal to the plane of spiral configuration of said trough.

6. A heat transfer fluid conduit wrapping for vessels according to claim 5 which has an arcuate length of about 270.

7. A vessel having a heat transfer fluid conduit wrapping welded to a surface thereof, which wrapping has adjacent continuous conduit portions which are spaced apart from one another, each such conduit portion being characterized by a transverse cross-section which is in the form of a trough with outwardly curved flaring edge portions which make lines of contact with said surface of the vessel, said wrapping being further characterized in that adjacent edge portions of said conduit portions are bonded to each other and to said surface of the vessel at said lines of con-tact by a single deposit of weld material in the space between said edge portions.

8. A vessel according to claim 7 in which said surface of said vessel is an exterior surface.

9. A vessel according to claim 7 in which said surface of said vessel is an interior surface.

10. A vessel according to claim 7 in which there is an angle of between 10 and 25 between the inner surface of the heat transfer fluid conduit wrapping and the surface of the vessel to which said Wrapping is bonded at their lines of contact.

11. A vessel according to claim 7 in which there is an angle of about 10 between the inner surf-ace of the heat transfer fluid conduit wrapping and the surface of the vessel to which said wrapping is bonded at their lines of contact.

12. A vessel according to claim 7 in which said wrapping is helically bonded to said surface of the vessel by a single helical deposit of weld material in the space between adjacent flaring edge portions of the wrappings.

13. A vessel according to claim 7 in which each conduit portion further comprises a rounded central portion and the radius of curvature of each of said outwardly curved flaring edge portions is about one third of the radius of curvature of said central portion.

14. A vessel according to claim 7 in which the thickness of the material of the wrapping is at least one third of the radius of curvature of each of said outwardly curved flaring edge portions.

15. A vessel having a first heat transfer fluid conduit wrapping as recited in claim 7 and a second heat transfer fluid conduit wrapping in the form of a trough having outwardly curved flaring edge portions, said second wrapping being bonded to the crown of said first wrapping by a single deposit of weld material in the space between adjacent flaring edge portions of said second wrapping which bonds said adjacent edge portions to each other and to the portion of the crown of said first wrapping between them.

16. A vessel according to claim 7 in which the vessel has an end surface which is substantially hemispherical and a first access opening fitting which extends through said end surface, the heat transfer fluid conduit wrapping being welded to said end surface and enclosing said fitting in a non-contacting relation; a collar making fluid-tight joints with said fitting and said wrapping to define a chamber between itself, said fitting, said wrapping and a portion of the surface of said vessel adjacent said fitting; and a second access opening fitting extending from said chamber through said collar, said wrapping having at least one lateral opening in the wall thereof which forms a boundary of said chamber to allow fluid to flow from the conduit defined within said wrapping into said chamber.

17. A vessel having a plurality of heat transfer fluid conduit wrappings welded to a side surface thereof in heat transfer relation with successive zones of said side surface of the vessel, each of said wrappings having independent inlet and outlet means, and each of said wrappings having adjacent continuous conduit portions which are spaced apart from one another, each such conduit portion being characterized by a transverse cross-section Which is in the form of a trough with outwardly curved flaring edge portions which make lines of contact with said side surface of the vessel, each of such wrappings being further characterized in that adjacent edge portions of each of said conduit portions are bonded to each other and to said side surface of the vessel at said lines of contact by a single deposit of weld material in the space between said edge portions.

18. A vessel having at least twoheat transfer fluid conduits defined on a surface thereof by first and second wrappings attached to said surface by welding, said wrappings each being in the form of a continuous trough characterized by outwardly curved flaring edge portions which make lines of contact with said surface, said first and second wrappings being interwrapped so that edges of said first wrapping lie adjacent but spaced apart from those of said second wrapping, and successive turns of said wrappings about said vessel being so close that their adjacent edges are bonded to each other and to said surface of the vessel at said lines of contact by a single deposit of weld material in the space between said adjacent edges.

19. A vessel having a rounded end surface and further having a heat transfer fluid conduit defined on this surface by a wrapping attached thereto by welding, said wrapping being in the form of a continuously curving, spirally-wound trough characterized by outwardly curved flaring edge portions along its open side whereagainst it is attached to said surface, said edge portions making lines of contact with said surface, and successive turns of said wrapping being in such spaced relation that their adjacent edges are attached to said end surface and to each other by a single deposit of weld material in the space between said edge portions.

20. A vessel according to claim 19 in which said end surface is substantially hemispherical.

21. A vessel having a flat end surface and further having a heat transfer fluid conduit defined on this surface by a wrapping attached thereto by welding, said wrapping being in the form of a continuous, spirally-wound trough characterized by (1) outwardly curved flaring edge portions along its open side whereagainst it is attached to said surface, said edge portions making lines of contact with said surface, and (2) rectangular configuration having mitred corners on successive turns, successive turns of said wrapping being in such spaced relation that their adjacent edges are attached to said end surface and to each other by a single deposit of weld material in the space between said edge portions.

22. The combination comprising (1) a vessel having a rounded end surface, (2) a first access opening fitting extending from the vessel through this surface, (3) a spirally-Wound wrapping attached to this surface by welding to define a heat transfer fluid conduit thereon and enclosing said fitting in non-contacting relation, (4) a collar making fluid-tight joints with said first access opening fitting and said wrapping to define a chamber between itself, said fitting, said Wrapping, and a portion of the rounded end surface of said vessel adjacent said fitting, and (5) a second access opening fitting extending from said chamber through said collar, said wrapping being characterized by at least one lateral opening in its wall forming a boundary of said chamber to allow fluid to flow from said conduit into said chamber.

23. The combination according to claim 22 in which said rounded end surface is a bottom surface and said first access opening fitting is an outlet fitting.

24. A vessel having a heat transfer fluid conduit wrapping welded to a surface thereof, which wrapping has (1) a plurality of substantially parallel conduit portions which are spaced apart from one another, each such parallel conduit portion being characterized by a transverse cross-section which is in the form of a trough with outwardly curved flaring edge portions which make lines of contact with said surface of the vessel, said parallel conduit portions being further characterized in that adjacent edge portions of said Wrapping are bonded to each other and to said surface of the vessel at said lines of contact by a single depositof weld material in the space between said edge portions; and (2) a return bend portion connected to adjacent ends of adjacent parallel conduit portions in a fluid-tight relationship therewith for providing a continuous conduit path through said wrapping.

25. A vessel according to .claim 24 wherein the longitudinal axis of saidreturn bend portion is substantially U-shaped and wherein said return bend portion is further characterized by (1). one end having an inlet opening thereat; (2) another end having .an outlet opening thereat, said one end being connected to an end of one of said parallel conduit portions in a fluid-tight relationship therewith and said other end being connected to an adjacent end of an adjacent parallel conduit portion in a fluid-tight relationship therewith; (3) a cross-section perpendicular to said longitudinal axis which is in the form of a trough with outwardly curved flaring edge portions which make lines of contact with said surface of the vessel; and (4) adjacent, spaced apart edge portions, the same being part of said outwardly curved flaring edge portions, which are bonded'to each other and to said surface of the vessel at said lines of contact by a single deposit of weld material in the space between said spaced apart edge portions.

26. A return bend heat'transfer fluid conduit wrapping for vessels adapted for attachment to a surface of a vessel by welding,- wherein the longitudinal axis of said return bend wrapping is substantially U-shaped and whereinsaid return'bend wrapping is further characterized by a cross-section perpendicular to said longitudinal axis which is in the form of a troughwith outwardly curved flaring edge portions, and wherein adjacent edge portions of said return bend wrapping are spaced apart and adapted to, be bonded to each other and to a surface of a vessel by a single deposit of weld material in the space between said adjacent edge portions.

27. A return bend heat transfer fluid conduit wrapping according to claim 26 wherein said cross-section is further characterized by a rounded central portion and wherein in said cross-section the radius of curvature of each of said outwardly curved flaring edge portions is about one third of the radius of curvature of said central portion.

28.A return bend heat transfer fluid conduit wrapping according to claim 27 wherein there is an angle of between 10 and 25 between a base plane extending between the edges of said return bend wrapping and a tangential plane along the line of contact between each said edge portion and the surface of the vessel.

29. A return bend heat transfer fluid conduit wrapping according to claim 26 wherein there is an angle of about 10 between a base plane extending between the edges of said return bend wrapping and a tangential plane along the line of contact between each said edge portion and the surface of the vessel.

30. A return bend heat transfer fluid conduit wrapping according to claim 26 wherein the thickness of the material of the wrapping is at least one third of the radius of curvature of each of said outwardly curved flaring edge portions.

References Cited by the Examiner UNITED STATES PATENTS 969,018 8/1910 Willmann 165-109 1,657,202 1/1928 Ellyson 165147 2,671,658 3/1954 Moore 165-147 X 2,772,860 12/1956 Nelson 165169 X 2,932,091 4/1960 Day 16516 9 X 3,228,466 1/1966 Carleton 165-169 FOREIGN PATENTS 1,060,659 11/ 1953 France.

43 2,970 8/ 1926 Germany.

646,866 6 1937 Germany.

804,008 4/ 1951 Germany.

ROBERT A. OLEARY, Primary Examiner.

MEYER PERLIN, Examiner.

A. W. DAVIS, Assistant Examiner.

Claims

1. A HEAT TRANSFER FLUID CONDUIT WRAPPING FOR VESSELS ADAPTED FOR ATTACHMENT TO A SURFACE OF A VESSEL BY WELDING, THE TRANSVERSE CROSS-SECTION OF THE WRAPPING BEING IN THE FORM OF A TROUGH HAVING A ROUNDED CENTRAL PORTION AND OUTWARDLY CURVED FLARING EDGE PORTIONS, AND THE RADIUS OF CURVATURE OF EACH OF SAID EDGE PORTIONS BEING ABOUT ONE THIRD OF THE RADIUS OF CURVATURE OF SAID CENRAL PORTION.