US1299344A - Boiler stay-sheet. - Google Patents

Description

A, R. HODGES.

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somznsmv SHEETQ APPLICATION FILED FB. '23. 19H.

Patented Apr. 1,1919.

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BOILER 'sTAY SHEET.

APPLICATION FILED FEB.23.19H.

Patented Apr. 1, 1919.

2 SHEETS-SHEET 2 UNIT PATEN orio ALLAN R. HODGES, E MEMrHIs; TENNESSEE, AssIeNoE or ONE-HALE T0 CYRUS A.

' MQALLISTER, or MEMPHIS, rEN-NEssEE.

To all whom it concern:

" Be it known that I, ALLAN R. l-lononsea citizen of the United States, residing at- Memphis', in the county of Shelby and State of Tennessee, have invented new, and useful Improvements in Boiler Stay- Sheets, of which the following is aspecification.

This invention relates to animproved boiler stay sheet, proposing a construction which is especially applicable, to locomotive boilers of the Jaco'bs-Shupert type.

i In such boilers thefire-box shell and the outer shell, are-composed of channeled sections Whose adjoining flanges are; secured together in steam-tight relation by rivets and the marginal portions of the stay sheets are interposed and secured betweensaid flanges; When the boileris fired, the fire' box shell becomes highly heated while the outer shell is still relatively cold with the result that the fire'box shell expands rapidly during an interval when the outer shell is the fire-box shell is coolingand,;hence, contracting, relatively slowly. The stay sheets which have heretofore been employed to brace .the shells relatively to one another are subject to severe counterstresses in connection with: the expansion and contraction of the shells, being under "severe compression when the fire-box shellis expanding relatively to the outer, shell and when the outer shell is contracting relatively to the fire-box shell andV-being-under severe tensionwhen the outer shell is subject to the expanding forcesdeveloped by combined heat and normal steam pressure; and said sheets by virtue of their integral or rigidconstruction and planar form are unable to resist the destructive effects of the stresses developed therein, particularly thecompressive stresses developedfin their transverse upper or arch portion and the shearing stresses developed intheirsides, theresult bei g tha im? a Specification of Letters Patent.

fire-box stay or BOILER STAY-SHEET.

Patented Apr. 1, 1919.

Application filed February 23, 1917. Serial No. 150,512.

comparatively short period of use they become distorted, buckled and ruptured, the breakage being particularly pronounced and of most, frequent occurrence along lines within the bridges or webs between the circulation openings and very close to theshells where the sheet by-virtue of the rivet securement of its marginal portions has greatest rigidity. WVhen thus ruptured the tensile strength of the sheet is impaired, as will be obvious, 'so that in time the sheet does not serve its intended purpose, 2'. e. does not adequately stay or brace the shells against steam pressure. There is no practical way to inspect the stay sheets for the purpose of ascertaining their. condition and it follows that sheets which are so badly ruptured as to be really unfit for servlce are retained through ignorance of their useless condition and in the unfounded assumption that they are substantially unimpaired.

The buckling and distortion of the sheets, apart from impairing their tensile strength, are a contributing factor in causing the loosening of the rivets by which the sections of the sheets are held together, with the resultof leakage at the seams.

The rigidity of the existing stay sheets also has a disadvantageous eifect on the shells since it impairs the capacity of the outer shell for utilizing its radial flexibility and, therefore, makes it more readily susceptible to the destructive effects of the stresses of expansion and contraction and further tends to,cause inwardbuekling and, not infrequently, rupturin of the relatively thin and more ductile the ox shell. I

The principal objects of the present inventionare to provide astay sheet which will not be subject to distortion, buckling or rupture, which will contribute to or augment the capacity of the outer shell for utilizing its radial flexibility, i. 6. its capacity for radial expansion or contraction, and which will not, cause buckling or rupturing of the shell, yet which will adequately brace the shells relatively to one another and which will conform to the standard requirements of locomotive boiler construction.

Further objects of the invention, especially'served bythe preferred embodiment disclosed are to provide a stay sheet which shall be of simple nd inexpensive construction and may be organized, as to its various parts and in relation to the shells which it braces, with comparative ease and facility.

As in prior constructions, the present stay sheet includes sling stays amongits component part; and such sling stays are included within the present invention and are specially constructed for cooperation with the stay sheets proper in serving. the principal objects of the invention.

WVith the stated objects in view, the invention consists of a stay sheet of flexible construction whereby the fire-box shell is permitted free radial expansion and the outer shell is permitted free radial contraction and whereby the said shells are adequately braced relatively to one another when the boiler is developing normal steam pressure; and the invention further consists in certain features of structure, combination and relation which will appear as the description proceeds.

An embodiment of the invention which, as now considered, is preferred, isillustrated in the accompanying drawings, wherein Figure 1 is a cross-sectional view ofv a locomotive boiler on the line 11 of Fig. 2 wherein one of the stay sheets appears in elevation;

Fig. 2 is a longitudinal sectional view of the rear portion of a. locomotiveboiler equipped with staysheets in which thefeatures of the invention are incorporated;

Fig. 3 is a side elevation showing a flexible joint employed to connect parts of the stay sheet;

Fig. 4: is an elevation of the joint shown in Fig. 3;

Fig. 5 is a side elevation showing the manner of engaging or articulating the'elements of the joint; and j 1 Figs. 6, 7 and 8 are detail plan, side and end elevations of one of the elements of the joint.

Similar characters of reference designate corresponding parts throughout the several views. r

In Fig. 2 a boiler is disclosed of the construction. which forms the subject of my copending application Serial No. 150,510, but it will be understood that the invention is applicable to boilers of various constructions and is'especially applicable to constructions of the Jacobs-Shupert type wherein the fire box shell 1 is made up of channeled sections 2, the outer shell 3 is made up of channeled sections 1 and the stay sheets 5 have their marginal portions fitted between the adjoining flanges of the channel sections 2 and 4E and secured by the rivets 6 which pass through said flanges and connect each section to its neighbors. a 1

In the embodiment disclosed and preferred, each stay sheet'5 comprises an inner arch member 7 which is connected to the fire-box shell 1, an outer arch member 8 which is connected to the outer shell 2, and flexible joints 9 between said arch members. To facilitatefthe organization of the parts of the stay sheet relatively to one another and to the shells 1 and 2 the outer arch member Sis made in sections 10, each of which is separately organized relatively to the arch member 7. The said arch members have straight sides; and the two outer sections 10 may constitute the'straight sides of the arch member 8 and are accordingly. each provided with several elements ofthe flexible joints ,9, for which companions .are formed on the arch member 7. Each of the intermediate curved sections 8 is provided with a single element of a flexible joint 9 for cooperation with a single companionelement suitably located on the arch member 7. V 1 j v The improved stay sheet is provided with the ,usual circulation openings 11 and manhole 12 located at the center of the steam space13 between the shells 1 and 3. In the construction disclosed, the elements of the flexible joints 9 are formed in or as parts of the-radial webs or bridges 1 1 between the openings 11,, including the two webs or bridges at the sides of the man-hole 12.. The arch, member 7 is provided with flat coplanar outwardly projecting radialfingers 1 5 and the arch member 8. is provided with similar and correspondingly located inwardly projecting fingers 16. ,The fingers 15 and 16 of each radially alining pair are companions and together constitute one of the webs or bridges l tj above mentioned.

The flexible joints 9 are preferably of the construction which, 7907 .96, forms the subject of my Letters Patent No. 1,249,959, granted December 11, 1917. Eachflexible joint 9 is composed of companion co-acting hooks 17 whichare formed as terminal parts of the respective fingers 15 and 16. Each hook 17 has parallel inner and outer legs 18 and 19, a how 20 connecting said legsand a terminal lug21 projecting in coplanar relation from theouter leg 19, the bow 20 having an opening 22 through which the lug 21- is inserted. .The arch members 7 and 8 are'in coplanar relation and this necessitatesthe offsetting. of the hooks 17 at relatively-opposite sides. of the companion fingers 15 and 16, as clearly shown in Fig. 5.

Inconsequence of the offset relation of the hooks..17 and of the relative thinness and ductility of the stay sheet, it is advantageous 9 rior to their articulation, The legs 18 and 19 are disposed in planes parallel'to the planes of the arch members and their spacing is such that the outer leg 19 of each hook fits slidably between the legs of the companion hook. vTo articulate thejoint the hooks are moved transversely relatively to one another, until the lug 21 of each hook alines with the opening 22 of the companion hook after which the hooks are moved longitudinally to cause the lugs 21 to pass through the openings 22, such longitudinal movement of the hooks involving relative outward radial movements of the respective parts by which said hooks are carried. The engagement of the lugs21 inthe openings 22 prevents di sengagement of the hooks by relative lateral displacement as is obvious; but said openings are of somewhat greater width than said lugs in order topermitsaid hooks a certain required measure of lateral play.

When the boiler is cold the hooks are disposed with the ends of their legs 19 in contact with the confronting bows 20, asshown in Fig. 3. On firing, the fire-box shell expands rapidly relatively to the outer shell and the hooks of the arch member 7 freely slide relatively to the hooks of the archmem her 8, both longitudinally in outward radial directions, and also to some slight transverse extent, depending on the radial inclination of the particular webs 1 1 with which said hooks may be associated. As the steam pressure develops, the outer shell expands and effects radial outward movements of the hooks of the arch member 8 whereby the loose play provided for by the preceding radial movements of the hooks of the arch member 7 is taken up uniformly throughout the stay sheet, suitably before the steam pressure attains its normal degree. There upon, the companion hooks 17 pull against one another, the lines of pull being substantially in the planes of the stay sheets,

whereby said stay sheets exercise their primary function of bracing the two shells rela tively to one another and of adequately supporting the fire-box shell. When the stay sheets are thus exercising their primary; function, further expansion of the outer shell is due to the ductility of the stay sheets and is confined to a range well within the limits of serviceability. On cooling, the outer shell is free to contract, its contracting action de veloping, in the manner above described, a certain measure of loose play in the joints 9 which is taken up or compensated by the subsequent contraction of the fire-box shell.

The arch member 7 are first secured to the fire-box shell in the course of the construction of said shell, after which the arch members 8 are secured in like manner to the outer shell. But in securing the arch members 8, its sections 10 are individually joined to the arch member 7 in the manner described, and

in consequence of such jointure, each section 8 isproperlylocated with reference to its neighboring section and with reference to the outer shell. When the sections 8 have been assembled relatively to one another, or in the course of such assembly, they may be, and preferably are, secured together, along their adjoining edges, by welding.

The stay sheet is braced across the manhole 12 by sling stays 24 whose arrangement, with reference to the stay sheet, follows the usual practice. Two or more of these sling stays, as preferred, are provided at each side of the stay sheet, as clearly shown in Figs. 1 and 2. The sling stays are made in inner and outer sections which are connected by flexible joints 9*- similar in construction, organization and operative effects to the joints 9 previously described, except for the fact that the bracing webs or bridges 23 of the joints 9 are not required.

' I claim as my invention 1. A stay sheet for locomotive boilers com-- prising an inner arch member for attachment to the firebox shell, an outer arch member for attachment to the outer shell and a series of radially disposed flexible joints connecting said members at regular intervals and effective to permit outward movement of the inner member and inward movement of the outer member and to stay said members relatively to one another, the outer member against outward movement and the inner member against inward movement, each of said joints comprising a pair of engaging companion members and having its said members formed as parts of the respective arch members.

2. A stay sheet for locomotive boilers having circulation openings and having its webs between said openings made of a pair of companion elements and a flexible joint connecting each pair of companion elements and effective to stay the fire box and outer shell against movements away from one another while permitting movements thereof toward one another, said joint comprising a pair of engaging companions members formed as parts of the respective companion elements of said webs.

3. A stay sheet for locomotive boilers comprising an inner arch member for attachment to the fire-box shell, an outer arch member for attachment to the outer shell, the outer member being made in sections adapt- 12 ed for individual assembly, said members having correspondingly arranged radial fingers projecting toward one another and defining circulation openings between which said fingers provide webs, and a flexible joint between the fingers of each web effective to stay the firebox shell and outer shell against movements away from one another while permitting movements thereof toward one another.

4. A stay sheet for locomotive boilers comprising an inner arch member for attachment to the fire-box shell, an outer arch member for attachment to the outer shell, the outer member being made in sections adapted for individual assembly, said members having correspondingly arranged radial. fingers projecting toward one another and defining circulation openings between which said fingers provide webs and a flexible joint between the fingers of each web comprising interengaging hooks, one carried by each finger, said hooks being cngageable by relative outward movements in their planes of the inner member and each section of the outer member and being effective to stay the firebox shell and outer shell against movements away from one another while permitting movements thereof toward one another.

5. A stay sheet for locomotiveboilers comprising an inner arch member for attachment to the fire-box shell, an outer arch member for attachment to the outer shell, a series of radially disposed flexible joints connecting said members at regular intervals and effective to permit outward movement;

member against outward movement and the inner member against inward movement, each of said joints comprising a pair engaging companion members and having its said members formed as parts of the respec tive arch members, said arch members being constructed to provide the usual stay sheet man-hole, and sling stays bracing said sheet across said man-hole, said sling stays being each made in sections and having a flexible joint between the sections of similar character to the flexible joints betwen the stay sheet members.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

ALLAN R. H ODGESi lVitnesses JOHN S. Powisns, JOHN L. FLETCHER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C.

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