US2186413A - Thermic siphon and the like - Google Patents

Description

C. G. HAWLEY THERMIC SIPHON AND THE LIKE Jan. 9, 1940.

Filed April 12, 1937 2 sheet$ $heet 1 1 XX W K501 Jan. 9, 1940. c. G. HAWLE-Y 2,186,413

THERMIC SIPj-IONAND THE LIKE I Filed April 12, 1937 2 Sheets-Sheet 2 INVENTOR. B Gharlesfiffiawley WW Q ma ATTORNEYS Patented Jan. 9, 1940 um'rsosmrss rear ewes THERIVIIG SIP'HON AND THE LIKE Charles -Gilbert Hawley, Chicago, 111., assignor, 1 by. mesne assignments, to Downflow Syphon Company, v Ohio Cleveland, Ohio, a corporation of r I Application AprillZ, 1937, Serial No. 136,485

3 Claims. (01. 122-68) This application is a continuation in part of my allowed application Serial Number 82,953, filed June 1, 1936.

A thermic siphon is a hollow vertical wall or 5 water leg which is installed in thefirebox of a locomotive and exposed to the fire therein. It serves to increase the heating surface of the firebox, and also functions to accelerate the circulation of the boiler water, and, to flood. or

protect the firebox crown sheet when the water in the boiler falls below the level of that sheet. Specifically, such wate'rs'teaming and circulating wall is.closed at the bottom but at the top opens upward. through the crown sheet.

The spaced sides of such siphon must be fas tened together by cross stays in order that they may support or sustain the internal boiler prese sure. This invention is chiefly concerned with l v hose fastenings and the benefits which fiow from the improvement thereof.

Commonly. the staybolts are threaded in the 7, parallel or opposed sheets or sides of the siphon and their ends are headed against the outer faces thereof. That construction is open to the zs'objection that permissible internal pressure is limited'to and by the bending strength of the connected sheets;-for if a sheet is bent or bulged between adjacent stays, it follows that the bolt holes in the sheet will be stretched and the structurewill become leaky.

-I -Iigher boiler pressure would be permissible only if larger bolts were used or if the bolts were more closely spaced. Such changes increase costs and tend to promote the accu'mulationof boiler scale: The same limitation is encountered in the fire sheets of the firebox itself, as distinguished from the siphons which the firebox contains. For the reasons above explained, it is common practice to limit locomotive boiler pressures to 250 pounds, or 300, pounds at the out-- side. A

The. object of this invention is to improve the staybolting of firebox sheets, including the sheets composing the described siphons and to permit the carrying of higher boiler pressures. Further," thermic, siphons usually serve to support arch brickv within the firebox, and a further purpose of the invention is to improve the means, for

supporting such brick upon or from such SlPhOIlSz- 5 1 Hereunder, both foregoing objects are attained byvdispensing with threaded staybolts and sub stituting cross bolts that are actually unified with the fire sheets which they connect or support.

Unification is accomplished by welding the cross :,bolts to the sheet. Fusion welding is employed,

the strength of a threaded and headed joint is face of a sheet, but being poorly united with the for the purpose, both the electric arc and the gas methodsusing the added metal which is required hereunder.

Pursuing this method the firebox sheets while originally perforated are'left intact; that is, with- 5 i out holes or joints; and the full tensile strength of each sheet is here made available; likewise the full tensile strength of eachsta'ybolt. Limitation to the bending strength of the sheet and to thus obviated and, a permanently tight firebox 15 provided. In this way both fireboxes and siphons may now be constructed to sustain boiler pressures two or more times higher than hitherto" allowablepa matter of great importance. And

"as well known, the thermal efiiciencies of a steam locomotive increase rapidly as steam tempera;

- tures are thus raised.

'At this point mention is made of the fact the m locomotive firebDX practice requires that each staybolt shall contain a tell-tale hole; so that any fractured bolt may be quickly locatedand replaced. The present invention includes the making of staybolts with axial tell-tale holes and yet admits of the fusion welding of the bolt ends to the sheets without destroying suchholes. Next, the welding of the fire sheets and the stay or cross bolts, as here practiced,- makes it possible to'employ bolts of greater than ordinary length and which extend beyond the fire sheets, in position tosupport arch brick. This explains the fore going mention of arch brick supports. Heretofore such supports have been welded to the fire readily built up by applied welding'materials, and

this without disturbing the weld or union between the fire sheets and the middle part'of the long bolt. I

The invention will bemore readily understood upon reference to the drawings that form parts i of this specification. In said drawings Fig. 1 is a vertical cross-sectionof the lower part of a thermic siphon in which the opposed sides of the siphon are joined or unified by the novel method and means comprising this invention;

4 pressure,

Fig. 2 is a like sectional view, illustrating slightly modified staybolt ends and welds and also showing a. longer cross bolt, the projecting ends of which provide supports for arch brick; Fig. 3 illustrates a modified form of the arch brick supporting bolt and also a slightly difierent formation of the bottom portion of the siphon; Fig. 4 is a cross-sectional view illustrating yet another form in which the lower part of the siphon may be made and stayed; Fig. 5 is an enlarged sectional view of the novel weld of this invention; Fig. 6 is an outer end view thereof; Fig. '7 is like unto Fig. 5 but illustrates a slight modification in the weld; and Fig. 8 is an end View taken from Fig. '7.

Figs. l to 4. are fragmentary cross-sectional views of the lower parts of different thermic siphons; i. e., different water steaming-and-circulating walls, each open at the top. No complete firebox and no complete thermic siphon is shown. Nevertheless the invention is adequately illustrated.

As will become apparent, the present invention is applicable to the end, top and side water spaces of a locomotive firebox, but most conveniently it is here illustrated as employed in building internal siphons or water walls, which are symmetrical shapes.

In each form shown, a narrow stean1-andwater space 2 is defined by spaced apart side or fire sheets 3, 3, the lower parts of which are joined and formed into a closed siphon bottom 4 of U-shaped cross section, or of the bulged shape 4' shown in Fig. 4.

The water space 2 is always occupied by water and communicates with the larger water spaces of the boiler. This thin, hollow wall is there- 'fore subjected to internal pressure and its flat side sheets 3, 3, require support against that Such support is provided by spaced cross bolts or stays that fixedly connect the opposed sheets and are constantly wetted.

Ordinary stay bolts are threaded and are I screwed into threaded holes in the sheets; and

afterward headed or upset, as required to form steam-tight joints. The present invention obviates the use of threaded bolts by fusion welding.

the bolts and sheets and thus providing better and more permanent unions between the parts. Further, this invention utilizes bolts that present smooth surfaces, less likely to retain scale and more easily cleared of scale.

The staybolts of this invention are of two kinds; first, the short staybolts marked 5, which are many in number; and second, the long staybolts 5 and 1, respectively shown in Figs. 2 and 3, which are few in number, only a single row being required to support a brick arch or firebox baffle.

The length of a short bolt 5 equals the overall width of the water wall, while the longer bolts exceed that dimension and thus provide projecting ends ta, that are utilized to support refractory arch brick 8, as well shown in Fig. 2.

All these bolts extend through holes of corresponding size provided in the fire sheets and the bolts are fixedly welded therein by a fusion proc ess, a proceeding which at once closes each hole and causes each bolt to become an integral part, of the sheet which it is to support.

Clearly, all parts are thus conditioned to provide a structure of mam'mum strength, and which may be placed in use without fear of leaky joints or of distortion by internal pressure or by sudden changes of temperature in the firebox.

As about to be described the welding is done from the exterior and by this method a water wall may be completed much more rapidly and economically than has been possible hitherto and the completed wall is adapted to long sustain any desired boiler pressure.

Referring as- Figs. 1 to 4 it will be observed that the left hand side of each figure shows the parts, sectionally, as they appear when first assembled; while the right hand side of each figure sectio-nally depicts the completed welded structure, ready for use.

Bolts of given diameter having been chosen and the spacing of bolts having been determined, the fire sheets 3, are punched; punches of bolt size being employed, fitting the sheets to freely receive the bolts.

It is no longer necessary to drill or ream bolt holes, for incipient cracks, possibly started by the punching operation, are completely healed by the fusion welding operation which follows the insertion of the bolts. In special cases involving brittle metals it is admissible to drill or ream these simple cylindrical bolt holes but ordinary firebox sheets do not require such expensive treatment.

All bolts 5 are smooth rods of circular cross section and present reduced ends 5 within the confines of the holes It in the sheets. In each case an annular space S is thus provided between the wall of the cylindrical hole 3 and the reduced end 5 of the bolt. Those surfaces are fused and that space is filled with fused welding material, W. In other words the method of depositing the weldingmaterial, whether electrical or gaseous, involves the fusing of the welding material and the fusion union thereof with all the surfaces defining the annular space S; resulting in a permanent union between the end of the bolt and the sheet, making them operatively integral.

The particular shapes provided by and comprising this invention are best shown in Figs. 5 to 8, which are enlarged to more clearly show the punched hole 3'in the sheet and the form of the. reduced end 5 of the bolt, which parts together define the shape and extent ofthe welding space S. The welding material W which integrally occupies that space is also here clearly shown. I

Fire sheets are commonly 7 thick and common staybolts' are of diameter. Such proportions are depicted in the drawings; from which it will be seen that the annular'space S is amply wide to admit the end of a welding rod. That much width is a requisite of the present invention, the width of the space S being varied or fixed to suit a chosen welding rod.

The reduced end 5' of the bolt is substantially cylindrical and the bottom shoulder 5 is preferably inclined or conical, as best suited to afiord a full strength union between bolt andsheet.

Next, it is to be noted that the shoulder 5 of the bolt may be positioned slightly within the hole 3 as shown in Fig. '7, by which means the bolt is nicely centered in the hole, in preparation for welding. Even when the bolt is thus centered in the plate the operation of welding may be depended upon to burn through the joint and particularly to avoid the corrosion which would occur in use.

As a preferred alternative the shoulder of the bolt may be positioned inward of the water side 3a of the sheet, as shown'in Fig. 5, and other means may be employed to hold the .bolt centrally in the hole while the welding operation is being performed. By preference this invention provides a three-pronged spacer 10, made of wire, and which is pushed down over the reduced end of the bolt, either before or after the bolt end. is positioned in the hole 3'. Thereafter the parts are welded together by deposited fused material and this light wire spacer loses its identity in the weldingmaterial, W.

The advantage of shifting the shoulder of the bolt inward as shown in Fig. 5 is that the opening in the sheet is more definitely closed by the Welding operation and the corrosion preventing weld part W becomes more pronounced.

The end of each bolt 5 may be flush with the fire side 31) of the sheet, leaving: no. metal to be burned away; The circumferential weld does not reach the outer end of the bolt, but by preference 7 presents its outer surface flush with or slightly below the fire side 3b of the sheet. Every bolt contains a central bore 5a called a tell tale hole, which is made originally; that is, before the bolt is assembled in the sheet.-

It is important tonote that the neck 5' of the bolt preserves its shape and entity, though firmly united with the weld material; this, notwithstanding the high temperature of the welding operation. In consequence; th'e tell-tale hole'is not closed or distorted and n0 final reaming operation is required.

The extended? brick-supporting staybolts of Figs. 2 and 3' should be compared as to their shapes, likewise the shapes of their welds. The middle or body part of the Fig. 2 bolt is heavily corrugated, see corrugations fib, in order that the bolt may present an extensive surface for the transmission of heat to the surrounding water.

The welds, W6 of Fig. 2 are quite the same as above described and serve the same purpose of 'unifying the bolt and the sheets.

Where a plain bolt 7 is used, as in Fig. 3, the weld shape is modified. The circumferential.

weld is marked W1 and is arrived at by flaring the holes 3' in the sheets and providing complementary grooves 10 in thebolt. In both cases ample space is allowed for the entrance of the welding rod.

The welding of 'staybolts as here described pre- I sents this further advantage: The side sheets may be separately formed and then staybolted; and thereafter, the bottom edges of the sheets may be joined by a longitudinal weld, WX. Ordinarily such welding could not be done after the sheets were staybolted, for in the case of threaded and headed staybolts the heat involved in the formation' of the weld, WX, would loosen such bolts, whereas the welded bolts of this invention are not affected by high temperatures. 1 a

A still further advantageof the present invention is that the fire sheets of a firebox wholly or partly conforming hereto may be hammered or bombarded to loosen scale and much more violently than usual, without danger of loosening the staybolts or starting cracks in the sheets.

While the present invention mayappear simple and almost obvious, it is in fact the result of much thought and research and is believed to be of far reaching practical importance.

I claim:

1. A hollow water wall. presenting spaced sides and cross stays which are metallically unified therewith, certain of said stays extending through one of said sides and providing durable archsupporting studs.

2. The improvement herein described comprising a sheet containinga cylindrical staybolt hole, in combination with a staybolt of like diameter presenting a reduced end within said hole and means adapted to center said reduced end in said hole in preparation for the deposition of welding material in the space defined by said hole and the reduced portion of the. bolt.

3. The improvement herein described comprising a sheetcontaining a cylindrical hole in combination with a staybolt of like diameter, shouldered and presenting acircumferentially reduced end within said cylindrical hole, and fusion welding material occupying the annular space defined CHARLES GILBERT HAWLEY,

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