US2893431A - Reinforced expansible tube - Google Patents

Description

July 7, 1959 v BO DW H 2,893,431

REINFORCED EXPANSIBLEI TUBE Filed Nov. 24, 1954 4 She'ets-Sheet l H 20 22 I8 W M/ 23 i;l I4 30 32 3| M Wm" 26 FIG.]SZ

um um K11 HIHII' IIL HIM 25 Ill- INVENTOR. HOEL L.. BOWDITCH AGENT July 7, 1959 H. L. BOWDITCH 2,393,431

REINFORCED EXPANSIBLE TUBE Filed Nov. 24, 1954 4 Sheets-Sheet 2 INVENTOR. l5 I6 HOEL L. BOWDITCH BY F AWE H @Etk AGENT July 7, 1959 H. BOWDITCH REINFORCED EXPANSIBLE TUBE 4 Sheets-Sheet 5 Filed Nov. 24. 1954 INVENTOR. HOEL L. BOWDITCH OUT y man/CA AGENT y 7, 1959 H. BOWDITCH 2,893,431

REINFORCED EXPANSIBLE TUBE Filed NOV; 24, 1954 4 Sheets-Sheet 4' ll mum m:

( By HOEL L. BOWDITCH IMJMAACL Y AG QNT United States Patent Ofice I 2,893,431 Patented July 7, 1959 2 ,893, 81 REINFORCED EXPANSIB LE TUBE' Bowditch, Foxhoro, Mass assignor to The Fox- I new Company, Foxb'oro'," Massa corporation of Massachusetts 1 Application Nb tmber 24, 19s4;.sens1No. 470,936

2 Claims." (0. 131-493 This invention relates to reinforced convoluted tubular .devices which areexpansiblelengthwise, such as bellowslike-structures with reinforcing means therefor.

Suchdevices areuseful, for example, as-fluid pressure sealing. units for movable: shafts, as flexible conduits, pressure sensing-elements, \valve motors, and the like. It is' important forsuch 'devices tosbe very flexible so that they can be-readily moved or adjusted according to the operational movement or adjustment required of them, and for this reason itisusually desirable 'toform the devicefrom relatively thin,v flexible metal. It is also important for such-devices tube-strong enough vto withstand the operational pressures and 'movements to be appliedthereto. According Ito the concept of the present invention, it is; further, important for such devices. to have relatively uniform,- linearityapproachingmovement and strength characteristics with respect to operational pressures as applied-thereto in various stages of movement or adjustmentthereof. Thus the output movement of such a device, according to this invention; closely approaches linearity with respect to operational pressures applied thereto; for the purposes of indication, recording, .or control; Further, the strength and flexibility characteristics of the unreinforced portions of the device accordingv to thisin-vention areandremain essentially uniform under variations of applied pressure and adjustment.

Thepresent invention provides, therefore, a reinfo'rced-expansible tube unit which-has highstrength under fluid 'pressure and with respectto the tube material, condition, and thickness dimension, and which is provided with "such form-andarrangement as to result inessentially linear movement response to applied pressure, and in such uniform-elongation or bending upon readjustment as-to avoid concentrated or spot areas of stress.

Thepre'sent-invention accordingly provides a reinforced 'expansible tube unit" which is particularly useful in applications involving high fluidpressures, for example,

pressures of the'order of up to 40,000 p.s.i., although there is no specific limit to the possible pressure range, since it depends in part on material, material condition,

. and dimensions.

It is therefore-an object of this invention to provide anew and improved reinforced expansible tube.

:It is a further object to provide a newand improved high: pressure bellowsstructure.

Other objects and advantages of this invention will be- 2. device (Figure I) as an illustration of the cross-section form of the device;

Figure V1 is an enlarged showing of a cross-section slice fragment of the device according to Figure V, and is an illustration of a tube formed in triple lamination as produced by initially providing acylindrical tube formed of three closely fitting telescoping sleeves;

Figure VII is a flexible coupling application showing of the structure of Figure I;

Figure VIII. is a valve stem seal application showing of the structure of Figure I;

Figure IX is an illustration of a device according to this invention withan internalshaft in longitudinal sliding fit within the convolutionsthereof;

Figure. X is a fragmentary illustration of a further alternate structure. in longitudinally central cross-section, wherein. the reinforcing ring, units are provided with dished guide and springlOadihgdiscs;

Figure X1 is a plan view ofone of the dished disc rejinforcingring. units asused. in the structure of Figure X;

Figure XII- is an. edge View of the ring unit of Figure XI; s

Figure. XIII is awalve motor. applicationshowing of thestructure of Figure I; and

Figure XIV is a pressure sensing showing, of. the structure of Figure I.

As amatter of convenience in the following description devices embodying this invention will be referred to hereinafter in the-specification as bellows units, in view of the bellowselike sidewall convolutions common to the various. embodimentsof this invention as disclosed herein. I

Figure I presents a bellows unit 10 as an illustrative embodiment of this invention wherein ametal tube 11 is provided with annular. transverse convolutions 12. Between and defined by the. convolutions 12, annular valleys 13 are provided, with'reinforcing ring units or bodies 14 mounted in the. valleys 13. Mounting, flanges- 15 and 16 are integrally secured to the tube, one at each end thereof. The flanges 15"and 16 are used to mount the bellows unit 10 on the particular assembly to which the bellows unit is to be. applied. Such arrangements are shown in Figures VII, VIII, XIII and XIV. Figure II. is a planview of'fiange 15. These flanges areshown as heavy discs such as may be used in high pressure applications. Bolt holes 17 are provided in the flanges 15,.16, for use in mounting the bellows unit, and the flanges are provided With central, cylindrical openings 15, 16' through which the cylindrical ends of the tube element application .11 are extended, in tight fitting integral mounting relation therewith. The flanges 1'5, 16 are further provided with annular outer end bosses 18 and. 19 in. laterally flaring continuationof the flange central openings 15 and 16'. The tube 11 is similarly flared within the flange bosses 18 and 19 and the outer ends of the tube and the flange bosses are welded together. in annular joining seals as at 20 and 21.'

The outer end faces of the flanges 15 and 16 are provided with annular step abutments 22, 23 and 24, 25' as means for aiding the fitting and sealing of the flanges to suitably cooperating portions of the members to which the bellows unit 10 is securedin its various applications. The inner end faces of the flanges'I5-and16are provided with annular abutments 26 and 27 which are curved? in cross-section to engage and match aiportionof the:curva ture of the first of the tube convolutions 12 at each end of the tube 11. Further, the inner end-.faces of'the flanges 15 and16provided with annularchannels-28nd 29 =whieh are curved and relievedin-cross-section to provide expansion room for the tube convolutions 12,. lengthwise of the tube 11. As may be noted hereinafter, this flange inner face arrangement is simply a continuation of the greatest dimension, the

arrangements provided by each of the convolutions 12 by the reinforcing ring units 14 which are adjacent thereto. Thus the flanges 15 and 16 abut on portions of the first of the convolutions 12 -at,their respective ends of thetube11. In

As shown in Figures I, III, IV, the annular reinforcing ring units 14 are formed with inner annular rings 30 and outer annular rings 31, and these rings are joined by an annular, narrow neck portion 32. With reference to dimension in the lengthwise direction of the tube 11 and the bellows unit 10, this dimension being the thickness dimension of the ring units 14; the outer ring has the inner ring has a lesser dimension, and the narrow neck has the least dimension. The ring ,units 14 are mounted on the tube 11 with the inner rings 30 bottomed in the convolution valleys 13. The convolutions 12 are reentrant between the inner and outer rein- 11, as permitted by the narrowness of the reinforcing 'ring neck 32. Consequently the convolutions 12 radially overlie portions of the reinforcing unit inner rings 30 and thus block off the reinforcing ring units 14 with respect to .movement radially out of the convolution valleys 13.

The configurations and dimensions of the tube convolushown generally in Figure I, are more clearly and acand VI.

The reinforcing unit inner ring 30 in transverse crosssection, i.e. centrally of the ring unit and lengthwise of the bellows unit as assembled thereon, is oval shaped,

.forcing unit rings 30 and 31 and lengthwise of the tube V curately shown in the enlarged showings of Figures V with the long dimension lengthwise of the bellows unit,

and has end faces 33 curved on a radius 34. The valley (13) formations of the tube 11 are in overall close engagement with the radially inner faces and for the most part the cross-section end faces 33 .of the reinforcing unit inner rings 30.

Thus the bottom portions of the tube valleys 13 are r I rigid and take no appreciable part in the flexing and elongation of the bellows unit. Further, very substantial reinforcement of the bellows unit at the valley areas is provided by the reinforcing ring units 14. This rein- 'forcement is not only transversely of the bellows units, vbut is also lengthwise thereof. Such lengthwise reinforcement is provided at the reinforcing unit inner rings 30, since portions of adjacent convolutions are rigidly separated at a fixed distance by the reinforcing unit inner ,ring 30 therebetween. Thus, the flexing and elongations of the bellows unit 10 is accomplished by flexing of the unrestricted portions of the convolutions 12. Further lengthwise reinforcement of the bellows unit 10 is promal, at rest condition is illustrated in Figure I, with the outer rings 31 somewhat separated from each other lengthwise of the bellows unit. However, endwise crush- ,ing or tilting forces on the bellows unit are limited in the effect they can have on the convolutions 12 by the fact that after a short movement of compression, the reinforcing unit rings 31 are seated on each other to form a rigid cylinder. The reinforcing unit rings 31 are formed a with flat upper and lower faces as a means of facilitating .units 14, while Figure VI shows a laminated tube 11" the same configuration may also be provided in a single 'thickness tube 11 (Figure V).

The reinforcing ring units 14 are formed with clearances 14 which provide room, both transversely and lengthwise of the bellows unit, for the convolutions 12 to be expanded without backing or external restraint as they areformed into a close approximation of ,a circuvided by the reinforcement unit outer rings 31. A norlar contour as indicated in Figure VI, radius 35. Fun ther, the clearances 14' provide room for the convolution to be flexed without hindrance throughout the operating range of the bellows unit, while essentially maintaining a circular contour, although the radius thereof may be slightly changed during such flexing. Such forming of the convolution provides a circular contour under tension and with an appreciable grain component, both in the direction of operational stress, generally lengthwise of the tube 11, as indicated in Figure VI by the arrows 36. Thus the convolutions 12 are provided with uniform dynamic strain, and have no undesirable concentrations of stresses. The dynamic relation of the circular form of the convolutions 12 as on the radius 35, to the circular forms of the curved ends 33 of the reinforcing unit inner rings 30 as on the radius 34, may be considered as one circle tangentially rolling on another circle. Further, as seen in cross section, Figure VI, the convolutions 12 are each made up of a circular portion 37 stemming from a curved wall relatively narrow neck portion 38,

jvolution. Such portions may vary somewhat in dimension as the bellows unit 10 is flexed, but the greater part of each flexure convolution is unhindered and unsupported by backing walls or the like, throughout the operating range of the device. Thus a bellows unit is provided which closely approaches linearity in its movement in response to fluid pressure as applied thereto.

The Figure VI laminated tube 11" structure provides the advantages of separate tube walls that may move with respect to each other during the forming and operation of a device according to this invention. Such an arrangement can be an aid in avoiding undesirable stress arrangements or concentrations in the tube. The Figure V and VI showings of this invention illustrate how the 13. This structural arrangement is indicative of the reentrant form of the convolutions 12, lengthwise of the bel- I lows, and with respect to the annular reinforcing units 14.

This device is provided with circular cross-section shapes in the convolutions 12, as illustrated in Figures V and VI. The annular reinforcing unit clearances 14 are suflicient to permit this action without any backing or support for these circular forms, even with the reinforcing ring units 14 held in close engagement with each other by the crushing pressure as applied endwise of the bellows unit. Consequently the convolutions 12, are under tension, uniformly, and in the direction of the circular cross-section form of the convolutions, Figure VI, arrows 36. Further, the grain form is appreciably in the direction of these arrows 36. Therefore flexing action of the bellows unit upon application of fluid pressure thereto closely approaches linearity of response. With this arrangement it will be seen that each of the convolutions 12 has a flexible portion which is a large part of the whole convolution with this flexible portion remaining flexible, unhindered and externally unsupported, as a whole, throughout the operating range of the bellows device. Certain small dimensional changes may occur, that is, the circular cross-section radius may change slightly during the operation of the device; the circular cross-section of the convolution may roll somewhat on the reinforcing unit inner ring 30; or there may be slight slippage between the neck portion of the convolution and the inner ring 30. In any case the dimensional changes thus brought about in the flexible portion of the convolution are relatively quite small, with no ible portion of the convolution 'or onthe linearity ofthe device. r

, Figure VII shows the bellows unit of FigureI in an application as a flexible coupling on a high pressure fluid flow pipe line. The bellows unit 10 connects two pipes 56 and 57 to form a continuous conduit therewith. The bellows unit flanges 1 5 and 16 are secured to pipe flanges 58 and 59, and the bellows unit is pressure sealed to-the pipe flanges. With t is arrangement the pipes 56 and 57 may be substantially out of alignment and the bellows unit may be subject to bending, without estab lishing stress concentrations in the bellows unit 10. This desirable condition is made possible by the form and construction of the bellows unit as described hereinbefore and involving its linear response, its uniform tension dynamically and statically, its grain disposition, and the circular cross-section configuration of the bellows construction.

Figure VIII shows the bellows unit 10 of Figure I in an application as a high pressure seal. In order to control flow in a pipe line it is conventional to mount a valve stem for movement through a wall of a control chamber. Under high pressure conditions such arrangements present difiicult problems with respect to sealing off the valve stem without undesirably alfecting its movement. The bellows unit of this invention provides a ready and practical solution to this problem, as illustrated in Figure VIII. In this figure, at the bottom thereof, an input passage 60 leads to a control chamber 61 through a valving aperture 62 and an output passage 63 leads from the chamber 61. A valve stem 64 extends into the chamber 61 and is movable to open and close the valving aperture 62. One end of the bellows unit 10 is secured and sealed to the fixed valve chamber housing and the other end is secured and sealed to the valve stem 64. In this showing the valve stem 64 is movable by a conventional fluid pressure diaphragm motor 65. The valve stem 64 is shown in two parts, but it is integral and solid from the motor 65 through the bellows unit 10 to the valving aperture 62.

Figure IX is an illustration of how a valve stem, or a shaft for other purposes, may be arranged within a bellows unit according to this invention. Figure IX shows a shaft 66 in sliding fit bearing relation with the inner walls of the bellows unit 10. This is, for example, a pressure seal structure such as item 10, Figure VIII, wherein the Figure VIII shaft 64 is enlarged, as at 66, Figure IX, to engage the inner walls 13 of the bellows unit. The valleys 13 may have cylindrical inner walls of special bearing material if desired. This arrangement also thus provides means for preventing undesirable tilting of the bellows unit.

Figures X, XI, and XII are illustrative of a further alternate structure of this invention. A part of this structure duplicates, to the limit of its fragmentary showing, the structure of Figure V. Additionally, however, each of the reinforcing ring units 14" is provided with a pair of dished, annular resilient discs or rings 69 as radially outward extensions of the main bodies of the reinforcing ring units. On each reinforcing unit the dished discs are placed in convex face to convex face relation with respect to each other. Under normal conditions, with the main bodies of the reinforcing ring units 14" in spaced relation with each other, the lower disc of one ring unit is in peripheral engagement with the upper disc of the ring unit next therebeneath. This engagement is spring biased lengthwise of the bellows unit. Consequently this form of this invention is spring loaded in the direction of elongation of the bellows unit, and the discs 69 provide another form of protection against bellows buckling or tilting.

Figure XIII shows the bellows unit 10 of Figure I in an application as a fluid pressure motor. That is, the bellows unit here is substituted for the Figure VIH diaphragm motor 65. In this Figure XIII structure, one end flange (15) of the bellows unit is secured and sealed to' a fixed mounting member 70, with a fluid pressure input passage 71 therein leading to the upper open end of the bellows unit. There'is no shaft within the bellows, and pressure applied therewithin produces responsive movement of the lower end bellows flange 16. This lower end of the bellows is sealed off against a solid mounting disc 72, and the upper end of a valve stem 73 is secured to the under side of the mounting disc 72. The valve stem 73 is extended to indicate its use in a valve block for opening and closing a fluid flow passage 74.

Figure XIV shows the bellows unit .10 of Figure I in an application as a fluid pressure sensing element. Such an element may have its lower end flange 16 fixedly mounted on a fluid flow pipe line 75, with an opening (not shown) providing access to the interior of the bellows from the pipe line 75. The upper end flange 15 of the bellows unit 10 is sealed olf against a solid disc 76 and is movable in response to fluid pressures applied within the bellows unit 10. As an indication of an application of such movement, a mechanical connection 77 is shown as operating an indicator 78, pivoted as at 79, with respect to a scale 80.

This invention, therefore, provides a new and improved reinforced convoluted tubular device, such as a bellowslike structure with reinforcing means therefor.

As many embodiments may be made of the above invention, and as changes may be made in the embodiments set forth above Without departing from the scope of the invention, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative only and not in limiting sense.

I claim:

1. A reinforced bellows unit comprising a transversely convoluted tube and annular transversely reinforcing ring bodies mounted on said tube between the convolutions thereof, said reinforcing ring bodies each having an inner annular ring, an outer annular ring, and a relatively narrow annular neck portion joining said rings, each of said convolutions extending between said annular rings of each adjacent ring body at the said annular neck portion thereof, and outer, lengthwise reinforcing and spring loading dished rings mounted on said outer anular rings, each of said outer rings being provided with a pair of said dished rings arranged convex face to convex face lengthwise of said tube, and the outer rim of each disc being in spring biased engagement with the outer rim of a disc on the next adjacent outer annular ring.

2. A flexible, reinforced bellows-like unit comprising an integral transversely multiconvoluted tube and individual reinforcing ring bodies mounted on said tube between the convolutions thereof, said reinforcing ring bodies each having an inner anular ring as a base form thereof with said base lying deep in the valley of one of said convolutions, an outer anular ring as a top thereof with said top lying above the peaks of the adjacent convolutions of said tube, and a relatively narrow neck portion joining said base and top to form a joining leg on a radius of said convoluted tube, each of said convolutions having a transverse cross section of essentially circular form in a plane extending lengthwise of said tube, which is substantially greater than a semi-circle and which bulges lengthwise of said tube to lie, on radii of said tube, between portions of the bases of the adjacent rings and portions of the tops of said adjacent rings, said rings providing, with each adjacent pair of rings, an annular housing chamber for one of said convolutions with an operating clearance for said one of said convolutions sufiicient to enable said convolution to maintain said circular cross section throughout the operating range of expansion of said tube, and said tops being formed and arranged for abutment with their adjacent tops as a limit stop system to limit the possible lengthwise compression of said convoluted tube.

(References on following page) Fulton Dec. 27, 1910 Sundh ..-Ju1y 22, 1919 Vuilleumier Nov. 30, 1920 Lawrence Oct. 6, 1931 Lord Dec. 8, 1931 May May 24, 1932 Zllea et a1 Nov. 29, 1949 10 8 Candee Aug. 7, 1951 Chyle Aug. 21, 1951 Zallea Mar. 17, 1953 Schindlex: et a1. July. 7, 1953 ZaHea; Jan. 18, 1955 Fentress et a1. Apr. 26, 1955 Schindler et a1. Jan. 17, 1956 FOREIGN PATENTS France Ju1y23, 1951

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