US2043426A - Thermic siphon - Google Patents

Description

JUN@ y W3- G. J. CHRISTENSON 'yf-)43,46

THERMIC S PHON 3 Sheets-Sheet l led July 8, 1935 5 I I I .Q A v \\w .N .k

Jun@ M3@ G. J. cHRlsTNsoN THERMIC S IPHON Filed July 8, 1935 3 Sheets-Sheet 2 June 9, 1936. G. J. cHRlsTEN'soN THERMIC SIPHON Filed July 8, 1.955 5 Sheets-sheet 5 Patented June 9, 1936 UNITED 515.6311515 IPn'rENT oFFleE THERMIC SIPHON -Gust J. Christensen, Chicago, Ill.,'assignor to Locomotive Firebox Company, Chicago, Ill., a corporation of Delaware y I Application July 8, 1935, Serial No. 30,288

'5' claims. (o1. 12a- 68) This invention relates to improvements in thermic siphons and it consists of the matters hereinafter described and more particularly pointed out in the appended claims.

One oi' the objects of the present invention is to provide a thermic Siphon for use in connection with a flrebox of the combustion chamber type and which siphon is so formed as to have such flexibility as will'prevent fractures developing from expansion and contraction caused.l by wide temperature changes.

, A further object of the inventionris to provide a multi-compartment siphon for use inra rebox of the combustion chamber type and wherein a part of one compartment is disposed inthe combustion chamber and has an inlet neck that opens through one o-f the sheets thereof and the other compartment has an inlet neck that opens prei- Aerably through the front throat sheet, the last mentioned neck though relatively straight,Y being of such length as to provide adequate ilexibility. Another object of the invention is to provide a multi-compartment therrnic Siphon including an inlet neck for each compartment, the longer neck being made integral with the body and communicating with the rear endV thereof and at the same time being transversely staybolted so as to resist the high internal pressure generated therein.

The above mentioned objects of the invention as well as others, together with the manyY advantages thereof, will more fully appear as I proceed with my specification.

In the drawings: Y

Fig. l is a longitudinal Vvertical sectional view through a relatively short' combustion chamber type of locomotive firebox embodying the -preferred formof the invention.

Fig. 2v is'V a transverse vertical sectional'view through a part'of the rebox as taken on the line 2--2 of Fig. 1l y Fig. 3 is a longitudinal vertical sectional view through a relatively long combustion chamber type of locomotive firebox embodying a vmodified. form of the invention.

Fig.` 4 is a detail vertical sectional viewv on an enlarged scale, through one of the inlet necks for the siphon shown in Fig. 3,the plane of the section being indicated by the line 4-4 of Fig. 3.

Referring now in detail to that embodiment of the invention illustrated in Figs. land 2 of the accompanying drawings,` the rebox therein shown, which is of the comparatively shallow, combustion chamber type, includes the crown sheet 5 which merges into the inner side sheets 6, the inner back lsheet 'I and inner throat sheet 8. The crown sheet extends vforwardly of the inner throat sheet 8 to form the top of the combustion chamber 9. VThis chamber is closed at the front end by a flue sheet II) and the bottom II of said' chamber joins the front end of the inner throat' sheet 8.

The outer back sheet is indicated at I2; the outer side sheets are indicated at I3 and the outer throat sheet is indicated at I4. Said sheets cooperate with the top sheet and outer side sheets I3 in forming the back Water leg I5, the side Water legs I6 and the iront throat I'I respectively, all in communication with the water'space Ill-of the boiler.

The back and side water legs and the Afront throat are bottomed by a mud 'ring I9 andportions, of the inner and outer back sheets are formed to Vcoact in providing a fuel door opening 20.

-Each siphon as herein shown comprises a flat hollow 4body formed to provide front and rear,

relatively deep compartments or chambers 22-23 respectively, separated by an intermediate compartment'24 of less depth; The body includes laterally spaced side walls 25-25 and transversely rounded front and rearV end walls 25 and 21 respectively. Said side Vand end walls are flared outwardly around the entire top end of the body,

into a laterally extending flange 28a. This iiange is fitted and welded as at 29 in a suitable longitudinal opening in thev crown sheet. Thus the Y open top end of the Siphon body provides a common discharge for all three compartments of theV siphon body, into the water space of the boiler abo-ve the crown sheet.

The front wall 26 oi the body is disposed at a relatively steep angle extending downwardly and rearwardly from the crown sheet and provides but a relatively small'amount of overhang for this end Vof the body. The rear wall 21 oi the body is also disposed at a relatively steep angle, substantially opposite that vof the frontwall and extends downwardly and forwardly to merge into a rounded corner or nose 21o. That part of the vby means of inside curved corners 28 to merge Y body defining the rear compartment 23 terminates in a stub-like tubular extension 3|.

Associated with said rear compartment of the siphon body is a downwardly and forwardly extending inlet neck 32 of substantial length. As shown herein, said neck is made from a piece of seamless tubing and the front end of said neck is anchored in a ilexible diaphragm 33 preferably flanged up from the top portion of the inner front throat sheet 8. The rear end of said neck is butt welded to the end of the body extension 3| above mentioned, as indicated at 34.

The bottom portion 35 of the front compartment 22 which is transversely rounded, is disposed above and arranged at a lesser inclination than that of the neck 32. This bottom portion along with the parts of the side and front end walls of the siphon body are formed to provide a stub-like tubular extension 36 for the front compartment of the body. Said extension or neck receives one end of an inlet tube 31 which extends downwardly and is curved slightly outward to be secured in a suitable diaphragm-like opening in the bottom of the combustion chamber so as to open into the water space of the boiler at this point. The inlet tube 31 is also preferably made of seamless tubing of a diameter substantially the same as that of the neck 32. When two siphons are used in a firebox, the inlet tubes for the front compartments of both siphons open through the bottom of the combustion chamber at points spaced, one on each side of the median line of said combustion chamber bottom.

The bottom of the intermediate compartment 24 is formed by the top portion or part of a substantially circular formation 38. Another portion of said formation merges into a rounded rear corner 39 for the front compartment and said corner blends into the rounded bottom 35 of said compartment. A third portion of said substantially circular formation forms the front end for the rear compartment and merges into the top of the stub-like tubular extension 3|..

Preferably the entire siphon body and the tubular extensions 3|-36 therefor, are made from an integral sheet, cut to such shape that when folded upon itself by means of asuitable form block, produces the body and extensions shown. Such an integral structure will have a line of weld extending the length of the front wall, along the bottom of the front compartment, around the substantially circular formation 38 and down along the top of extension 3|. Also, a line of welding will follow down along the rear wall 2l to merge into the corner 21a, said line of welding being necessitated because of the removal of certain excess metal from the sheet, that permits the making of the inclined rear wall of the body without a puckering or buckling at said corner. To brace the body of the siphon against internal pressures, the same is transversely staybolted as at 4D. Due to the outline shape of the body, less staybolts are required than in a conventional siphon body and this without sacrificing the safety factor.

Instead of making the entire body and the main inlet neck from a single sheet of metal, that part of the body comprising the front compartment may be made from a single sheet of metal and that part of the body comprising the rear compartment and the main inlet neck extension may be made from a single sheet of metal and the two parts joined by butt welding at about the middle of the intermediate compartment 24.

While a two part body requires more welding operations, it has certain advantages in the economy in plate material, due to the use of smaller sheets and to the manner in which the grain of the metal in the two sheets thus used, may be disposed. Whichever way the siphon is fabricated, that is, either from one or two sheets of metal, the operation of the siphon is the same and the advantages gained over the conventional siphons are likewise the same.

In either instance, the arrangement of the parts is such that the relatively long neck is under compression when in a cold condition as when there is no re in the rebox. Such compression, of course, is in relation to the body of the siphon and substantially equals the amount of the movement due to expansion, as when the firebox is being fired under service conditions. Under such conditions, when the siphon is under service heat and pressure, only slight stresses, incapable of starting fracture at the inside corners previously mentioned are present because the force of the expansion will return the neck and the upper part of the siphon to their normal positions and thus neutralize the movement thereof.

In Fig. 3 of the drawings, I have illustrated the invention as embodied in a rebox longer than that shown in Fig. 1 and having a combustion chamber 9a Aof greater length. To adapt the siphon to the increased length of iirebox and combustion chamber, the length of the siphon body 2|a is increased accordingly. Preferably, this increase in length of the siphon body is made up in the front end chamber 22a so that a goodly portion of said front end chamber is disposed entirely within said combustion chamber. With such a front end structure, the front wall 26a is arranged at a greater inclination than in the structure shown in Fig. 1.

While the length of the front compartment is thus increased, the length of the rear compartment 23a preferably remains the same as before and its position or spacing with respect to the inside back sheet 'la remains the same as before. Thus the distance between the tubular extension 3|a, and the inside throat sheet 8a becomes greater to'necessitate an inlet 32a of greater length.

By reason of the use of an inlet neck of greater length, greater flexibility in the neck is inherent. Therefore, in such a construction it may be preferable to staybolt the intake neck. Furthermore, if the neck is stay bolted it is not necessary that it be of seamless tubing. The conventional practice of making the neck integral with the body may be followed when the device is so formed. Under such conditions the body of the siphon may be made from one or more metal sheets of the proper outline shape folded to form the body and the neck 32a. 'I'he neck 32a will then be 0f a circular cross section having a line of butt welding 32h along its top as best shown in Fig. 4. Such a welded neck is preferably staybolted as at 32e` to reinforce the same against internal pressures. Under ordinary practice, a staybolted neck may have more rigidity, but due to the length of the neck herein described, the requisite flexibility desired is still present. In all other respects, the siphon includes the same structure as that described in connection with Figs. 1 and 2.

When the use of an arch is desired in the fire-l box, arch tubes 4| may be employed in connection with the necks 32 or 32a and which arch tubes are arranged parallel with and in the inclined planes of said necks. Such an arch may consist of bricks 42 all of the same pattern shape at their side edges. This avoids the expense of using bricks of different pattern shapes at said edges. The bricks thus used will have a better supporting engagement upon the necks and arch tubes than is afforded by the bulge on the conventional siphon.

By reason of the construction described, it is apparent that because of the siphon having a greater length, the same increases the superficial area and consequently the heating surface of the siphon. This induces a greater water evaporating and steaming action and fore and aft water circulating action in the boiler so that quiescent areas are substantially eliminated and sediment accumulation prevented. Again, such a structure avoids the necessity of using a separate Siphon in the combustion chamber and this of course, reduces manufacturing and installation costs.

While in describing the invention, I have referred in detail to the form, 'arrangement and construction of the various parts thereof, the same is to be considered only in the illustrative sense so that I do not wish to be limited thereto except as may be specifically set forth in the appended claims.

I claim as my invention:

1. In a locomotive boiler iirebox having a combustion chamber, a hollow water steaming and circulating wall including a body, a tubular inlet neck for said wall communicating at one end with the front bottom part of the body and opening at the other end through a part of the combustion chamber into the adjacent water space of the boiler, a second tubular inlet neck com-municating at one end with the rear bottom part of the body and opening at the other end into water space of the boiler rearwardly of the combustion chamber, said body having a single outlet opening through the crown sheet of the firebo-x for the discharge of water supplied to the body by said inlet necks.

2. In a locomotive boiler rebox having a combustion chamber, a hollow water steaming and circulating wall, the top oi which presents an elongated opening in the crown sheet of the firebox with the iront end of the said wall projecting into the combustion chamber, an inlet neck for the said front end of said wall and opening through a rebox sheet forming a part of the combustion chamber and a second inlet neck for the rear end of said water wall opening through a rebox sheet at a point rearwardly of the combustion chamber.

3. In a locomotive boiler firebox having a combustion chamber, a hollow water steaming and circulating wall, the top of which presents an elongated opening in the crown sheet of the rebox with the front end of the said wall proiecting into the combustion chamber, an inlet neck for the said front end of said wall and opening through a iirebox sheet forming a part of the combustion chamber, and a second inlet neck for the rear end of said water wall opening through a rebox sheet at a point to the rear of the combustion chamber, the second mentioned inlet being straight and having a length greater than the first mentioned one which is curved.

4. In a locomotive boiler rebox, ,a hollow water steaming and circulating wall including a body presenting an elongated opening in the crown sheet of the firebox and comprising spaced, 9

staybolted sides butt welded at their meeting edges, each side including an integral semi-circular neck extension, butt welded at their meeting edges to form an inlet neck for said body communicating at one end with the water space oi the boiler below the bottom of the iiues therein and communicating at the other end with the bottom of the body at a point rearward of its front end, said neck being transversely staybolted.

5. AV thermic Siphon including a flat hollow body, a relatively long straight, downwardly extending inlet neck for the Vrear end of said body and a relatively short curved, downwardly extending inlet neck for the front end of the body.

GUST J CHRISTENSON.

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