US2239908A - Stay bolt for boilers - Google Patents

Description

April 29, 1941. c. v. BAUER Erm. 2,239,908 STAY BOLT FOR BOILERS Filed May 6, 1939# l 2 SheetSShe6t l 0. Y o. m s. w m* u www 9 fm Y fO 3 Q VU.0YW 2:.. NHUJN A .2 w /wznw 2 :Hmm #l Upa/Af :i NQ .l I I l l l l IIAI'., f -Il if L mw vr n w. m... W l E m m e. mw u F w. i@ Q r m m v o@ k 3 B h April 29, 1941.

Patented Apr. 29, 1941 Cletus V. Bauer, Yonkers, and Frank P.

Port Richmond, N.

deceased, late of Yo Cina,

Y., and Charles J. Zusy, nkers, N. Y., by Kathryn Zusy, administratrix, Nassau, N. Y.

Application May c, 1939, seria1N0.272,oss

(ci. :ss-1.5)

1 Claim.

This invention has to do with stay boltsfor boilers, and it is concerned particularly with stay bolts for use in boilers for locomotives. The usual boiler construction has an inner and an outer wall with the inner wall defining, or at least partially deiining, the fire box or combustion chamber, and the space between the walls is for water or steam, or both.

These two walls are commonly referred to as inner and outer walls, although the inner wall is also referred to as the fire box sheet, and the outer wall as the wrapper sheet. These two walls must be united with each other, and this is done by what are termed stay bolts which connect to the walls and extend across the space therebetween.

It has been found that relative movement takes place between these walls due to expansion and contraction, it being appreciated that the inner or lire box sheet is exposed directly to the re or llame, while the outer or wrapper sheet is more or less insulated from the combustion chamber by the body of water between the sheets. Then, too, relative movement or relative vibration may result due to movements incident to the travelling of the locomotive along the track-way wherein there are considerable twisting and rocking and weaving actions.

Stay bolts have been proposed wherein one end of the bolt has a connection with one sheet or plate which permits relative movement, but the opposite end had a fixed or rigid connection with the other sheet.` Usually the fixed connection was with the inner or lire box sheet, and when relative movement between sheets took place, the bolt, although capable of movement with one sheet, sets up strains or twists in the other sheet due to the rigid connection, and this results ultimately in failure of the sheet with the rigid connection, the stay bolt, or the connection between the two, or failure residing in the combination of these three.

The present invention is directed toward the provision of an improved Astay `bolt structure wherein the bolt is capable of movement relative to both the iire box sheet and the wrapper sheet. In this connection, the bolt effectively holds the sheets against separation incident to pressure between them, or the like, and at the same time seals the space between the sheets so that the space therebetween effectively retains water or water and steam and under the attendant steam pressure. To these ends the structure embodies a movable connection between the stay bolt ends andthe sheets, both of which may be in the CII nature of ball and socket joints or seats. The connection with the wrapping sheet may be sealed in the usual manner, but the vconnection with the fire box sheet `cannot be sealed with anything which. projects materially into the fire box, else such projection would be burned olf. Accordingly, a seal structure is embodied within the water area between the sheets, and this seal structure advantageously includes a exible metal element in the nature of a bellows.

Structures for carrying out the invention are shown in the accompanying drawings wherein: Fig. l is a general cross sectional view taken through an exemplary boiler structure illustrating the inner and outer sheets, and generally Aillustrating the stay bolts.

Fig. 2 is an enlarged cross sectional view showing a stay bolt and its connection with the two sheets.

Fig. 3 is a View similar to Fig. 2 showing a modified arrangement.

Fig. 4 is a view similar to Figs. 2 and 3 showing a further modied arrangement.

The boiler. structure shown in Fig. 1 has an outer sheet or wrapper sheet l, and an inner or lire box sheet 2. The fire box sheet denes the combustion chamber as illustrated, while the space 3 between the sheets is for water. This space is usually enlarged in the upper portion of the boiler, as illustrated, this being a space for water and steam. As shown in Fig. 1 a multiplicity of stay bolts connect the inner and outer sheets, the bolts proper being illustrated at 5 and there being stay bolts at each of the locations indicated by the circle as at 6. In some cases the inner and outer sheets may be substantially parallel with each other as shown in Figs. 2, 3, and 4, while in others they may be angularly disposed relative to each other, and the distance between the sheets may vary. However, in Figs. 2, 3 and 4 the sheets are shown as being substantially parallel with each other,.as this illustration will suilice for showing the bolt structure.

The attachment of the bolt 5 to the outer sheet may follow a conventional structure which resides in the provision of screw-threads 1 on the outer end of the stay bolt, with a partially spherical nut 8 screw-threaded thereon and seated in a recess 9 in the wrapper sheet. The nut 8 may have opposite slots or recesses I0 for the reception of a wrench. A cap Il may be placed over the nut 8 and welded to the wrapper sheet completely around the meeting edges, as

shown at I2, to thus seal the connection between the bolt and the wrapper sheet.

The connection with the iire box sheet advantageously takes the form of a sleeve i5 welded in an aperture in the sheet 2. The weld connection is illustrated at around the circumference of 1e sleeve. The sleeve I5 preferablyhas an enlarged tapered portion or frusto-conically shaped portion as at lI which ts on a tapered seat E8 defining the aperture in the nre box sheet. The boit 5 is provided with a partially spherical head 25 which is arranged to seat in a partially spherical or tapered seat 2i in the sleeve I5.` Q

It will be noted that theV joint between the sleeve and the fire box sheet is completely sealed by the weld connection at IS. However, it is also necessary to seal the joint between the sleeve and the head of the bolt against escape of water. This is preferably done by the use of a flexible metal bellows 22 having a tight or sealedconnection with` the bolt and with the sleeve I5. To this end the sleeve. may be fashioned with an off-set, and the bellows has a projecting end 24 seating on theinner wall 25 of the projection formed by the off-set. A shrink ring 25 is placed over the end 24 of the bellows. This assembly is made with the shrinkring in heated condition so that upon cooling the ring contracts and clamps the projecting end 24.0f the bellows against the Y shoulder 25 to form a substantially water-tight joint; In making the assembly the shrink ring is passed'over the bellows and end 24 and then the shrink ring is cooled. The opposite end of the bellows has a projecting end 21, and a shrink ring 28 encircles the same. This assembly is made with the shrink ring heated so that upon cooling it contracts and clamps the end 21 of the bellows against the stay bolt to form a substantially water-tight joint.

The assembly comprising stay bolt 5, together l5 and extends entirelyv with the sleeve I5 and the bellows 22, with the shrink rings in position, is preferably supplied as a unit. In manufacturing the unit, the bellows and* sleeve I5 may be rst united by the application -of theshrink ring 26. Thenthe bolt may be telescopedinto the sleeve and bellows with movement, for example, from left toA right, as Fig. 2 is viewed, and then the shrink ring 28 is applied. This completes the sub-assembly of the stay bolt. The nut 8 andthe cap II are supplied disassembled, although the nut may be temporarily screwthreaded onto the bolt.

' In mountingthe stay bolt in the boiler the subass'embly comprising the bolt 5, sleeve I5, bellows 22fand the'shrink rings, are passed through the aperture in the fire box sheet 2, and then the nut 8 may be applied from the outside of the wrapper sheet. The weld connection I6 may then be made, and after proper adjustment of the nut S, the capv II may be welded to the wrapper sheet. Accordingly, it will be noted that the cap II effectively seals the movable connection of the stay bolt with the wrapper sheet while the bellows and the weld connection I6 effectively seal the connection of the bolt head with the sleeve I5, and the sleeve I5 with the inner or fire box sheet.

When relative movement between the sheets I and 2 occur, as for example by a relative up and down movement as` Fig. 2 is viewed, the nut 8 is free tof swivel or rock in its seat on the wrapper sheetv andthe partially spherical head 2B is free to moveor rock in its seat 2| on the sleeve. This action places no strains or stresses or twisting action on either of the sheets so that there is no tendency to weaken the same or work the connection loose. Moreover, this movement sets up no twisting strains or other stresses on the bolt itself. The flexible bellows 22 takes care of this movement, but the forces required to partially collapse or twist the bellows are very small. It will be understood that the connection effected bythe shrink ring 28 is a xed one relative to the bolt as distinguished from a sliding connection. In other words, the bellows is not arranged to expand or contract axially of the bolt, but is intended only to take care of that twist-like movement whenthe sheets shift relative to each other. The bellows may be made of any metal suitable forl the purpose, depending upon the requirements, as for example, copper, brass, ferrous metal preferably of the stainless or non-corrodible type, such as the so-called stainless steel, or a copper-nickel alloy, or the like.

In Fig. 3 the connection with the re box sheet 2 is substantially the same as that just described, and the same reference characters are applied. This structure, however, shows a different sort of connection with the wrapper sheet. In this form a sleeve Sil is welded to the wrapper sheet as at SI, and it is fashioned with a seat for the spherical nut 8. A cap 32 is-screw-threaded to the sleeve 3), and the seal is effected by a gasket 33. This arrangement may be preferred in some structures.

In Fig. 4 the structure for connection to the fire box sheet is substantially the same as that shown in Figs. 2 and 3, while a further modified arrangement for connection to the wrapper sheet is shown. With this arrangement the surface on the outside of the wrapper sheet is substantially flush in that it does not have the projecting cap II or the projection constituted by the sleve and cap 3i! and 32. In this form a sleeve 40 is inserted in'an aperture in the wrapper sheet I and is welded thereto as at 4I. This sleeve has a spherical socket 42 for receiving the nut 8". The seal is provided by a plug 43 screw-threaded into thesleeve-Ii preferably with the use of a gasket 44. ball and socket connection with the fire box sheet can be employed with various types of connections to the wrapper sheet.

In the forms-shown the bolts have axialfbores A5 giving the bolts a hollow formation. This structure is for testing purposes, but forms no part of the present invention, and the bolts may or may not employ such structure. The .head of the bolt and the nuts used therewith, together with the respective seats, are shown asbeing of the partial spherical type, thus vforming ,ball and socket type of joints. The invention is not, however, to be limited to this structure, since the seats may not be rounded to nt the nuts, butmay be of tapered form and the boltk head and nut may likewise embody such variation in shape as may yet permit adequate rocking or oscillation upon the seats.

What is claimed is:

A stay bolt assembly for ruse between the fire box sheet and the wrapper sheet of a boiler comprising, a bolt having a head at one end, a sleeve positioned over the bolt, said sleeve having a seat for the bolt head and the bolt head and* seat forming a ball and socket type connection, said sleeve being arranged to besecured in an aperture in the fire box sheet and to have its major portion lie between the said sheets of the boiler whereby the head ofthe bolt is countersunk and Adoes not project beyond' the lire box sheet, a

Thus it will be seen how the movable or metal bellows positioned over the bolt between the said head at one end and the opposite end of the bolt so as to lie between the said boiler sheets, said bellows having one end projecting to overlie a portion of the sleeve, and its other end projecting for substantial contact with the, body of the bolt, and shrink rings applied over the eX- tending ends of the bellows for clamping said ends respectively to the sleeve and bolt for sealing the connection between the bolt head and its seat.

CLETUS V. BAUER. FRANK P. CINA. KATHRYN ZUSY, Administrtrzx of the Estate of Charles J. Zusy,

Deceased.

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