US2151441A - Thermic siphon - Google Patents

Description

March 21, 1939'.

E. J. REARDON THERMIC S I PHON Filed June 2, 1958 Patented Mar. 21, 1939 UNITED STATES PATENT OFFICE THERBHC SIPHON poration of Delaware Application June 2, 1938, Serial No. 211,422

14 Claims.

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. The thermic siphon with which the present invention is more particularly concerned is anelement employed in a locomotive firebox for increasing the water steaming and circulating eificiency of the associated boiler. Such an element generally takes the form of an upright, flat hollow body, the open top of which is operatively engaged in the crown sheet, to form the outlet of the element. Said element often includes a downwardly and forwardly extending bottom that terminates in a tubular neck which opens through one of the other sheets of the firebox to form the inlet or intake for the element.

In order to obtain as much heating surface as possible, it has become the practice to increase the length of the element as much as the conditions in the firebox will permit. It is also the common and desired practice to employ a fire arch in connection with such elements, the arch being supported by engagement with the bottom portion of the element. Again in order to accommodate properly the products of combustion as they leave the fuel bed so that they may pass over the arch to the flues, it is necessary that the upper end of the arch be spaced a considerable distance downwardly from the crown sheet. Because of the space limitation within the firebox, a design having the above desired characteristics results in the bottom portion more nearly approaching the horizontal than is the. case where a relatively small element is used or where an arch is not desired. In other words, the bottom portion of the element has a relatively smaller inclination or pitch.

Thus in constructions wherein the bottom is of low pitch, it is obvious that the water cannot as readily rise along said bottom as it could in a construction having a greater inclination or pitch. In short, circulation of the water along the bottom wall is not as rapid and vigorous as is the case where the bottom is of steeper pitch.

With the less rapid circulation of Water along the bottom of the element, certain conditions arise in the element itself which the present invention seeks to overcome. For instance, when such elements are employed in connection with a fire arch, the area of the element on the underside of the arch directly exposed to the fire in the firebox is relatively small. Thus the fire is concentrated or confined to a small area of the element before it spreads out to pass to the other parts of the firebox on its way to the fiues. In

oil burning locomotives, this condition is more noticeable because of the concentration of the flame on one spot or surface of the element. Under such conditions, the water in the element on the water side of said spots or areas is often flashed into steam causing the formation of a steam pocket or vapor lock in the bottom of the element which the relatively slower moving water does not immediately dislodge. This prevents flooding said spots or areas with water. Such locks or pockets being devoid of the cooling effect of the circulating water, the metal of the element is in a dry condition. At times the metal of the siphon in the area of said pocket becomes overheated and may even be pressed outwardly as a bulge or blister. At times cracks or fissures appear and in some instances said elements burn out at these spots or areas.

One of the objects of the invention is to provide simple and efiicient means in a thermic siphon for automatically and continually coducting cooler boiler water from beyond the outlet end of the siphon and directing and discharging it against those portions of the element along which steam pockets and vapor locks have a tendency I to form.

A further object of the invention is to provide means for use in elements of this kind which has no moving parts and requires no attention so that the life of the associated element and the periods between required servicings are increased.

Another object of the invention is to provide means whereby the water moving upwardly in the siphon can be divided into streams which assist in preventing conflicting currents and hence facilitate the rapid discharge of the heated water and steam.

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

In the drawing:

Fig. 1 is a longitudinal vertical sectional view through the firebox end of a locomotive boiler embodying the preferred form of the invention.

Fig. 2 is a transverse vertical sectional view on an enlarged scale, as taken on the line 22 of Fig. 1.

Fig. 3 is a detail horizontal sectional View through a part of Fig. 2 as taken on the line 3-3 of Fig. 2.

Referring now in detail to that embodiment of the invention illustrated in the accompanying drawing and more especially to Fig. 1 thereof, the firebox therein shown comprises a flue sheet 5,

rear sheet 6, crown sheet 1 and side sheets 8, the bottom portion of the flue sheet forming the inner throat sheet 9, all arranged in themanner found in fireboxes of this kind. ill indicates the barrel of the boiler, H the top sheet thereof and I2 and I3 indicate the outer throat sheet and the back sheet thereof respectively. The sheets lll2 l3 coact with theconventional outer side sheets (not shown herein) in providing the usual side Water legs and the front throat l4 and back water leg l5 respectively, all bottomed by a mud ring and which mud ring appears in Fig. 1. In the boiler shell are the fines l6 which extend forwardly from the flue sheet toward the usual smoke,

box and l 1 indicates the fuel door opening formed by coacting parts of the sheets 6 and I3 respectively. The construction above described, which of course is staybolted in the conventional manner, may well be taken as typical of that found in locomotive boilers now in general use.

To increase the water steaming and circulating efiiciency of such boilers, additional heating elements are employed in the firebox and such elements usually draw boiler water from a water leg or other point and discharge the same through the crown sheet. By way of illustration and not by way of limitation, I have illustrated a construction in which the intake is at the front water leg.

l 8 indicates such a siphon or element as a whole and the number and size of such elements or siphon employed in a firebox is dependent upon the width and length of the firebox. Said siphon, as here shown, comprises a flat hollow body E9 of substantially triangular shape and a tubular inlet neck 20. The siphon body includes spaced side wall 2l2|, front and rear walls 22 and 23 respectively and a downwardly bulged bottom portion 24 that merges at one end into the neck and is connected by a rounded corner or pocket 25 with said rear wall. The corner 25 is spaced downwardly a considerable distance from the crown sheet. Such a construction is often desired because it permits the use. of a longer brick arch 26 without bringing the rear top end of the arch too close to the crown sheet. In other words, a considerable throat is provided between the arch and the crown sheet. A part of the brick forming this arch rests upon the top portion of the bulged bottom of the siphon. Thus, it is apparent that only a relatively small portion .of the siphon, as formed by said bottom is exposed to the flames in the firebox beneath the arch. It is also clear that the bottom of the siphon is of less pitch or inclination than if the bottom extended to a point closer to the crown sheet but still in the plane of the wall 23.

The side walls 2 l--2l of the body of the siphon are connected together by staybolts 21. The top end of the side and end walls of the siphonare flanged outwardly as at 28 to engage and be secured in a suitable opening provided therefor in the crownsheet. As shown herein, the bottom end of the neck 28 is engaged in and welded to a flexible diaphragm 29 formed in the inner throat sheet.

In operation the siphon is subjected to the heat of the burning fuel in the firebox andthis, of course, raises the temperature of the water whereby a portion is converted into steam. Such steam and water in the siphon are displaced by the heavier and cooler water from the neck 20 and lower part of the boiler, to pass upwardly through the siphon body into the boiler water space above the crown sheet. This action results in the 'entrance of water from the front throat l4 and through the neck 20 at a high velocity. As the water enters the body from its neck, it expands so that its velocity is reduced with a corresponding reduction in water movement along the bulged bottom as the water and steam bubbles move upwardly in the body. By reason of the arch, it is apparent that with only relatively small areas of the siphon being exposed below the arch, the flames have a concentrated or confined action on said exposed areas. This action almost instantly flashes the water along said areas into steam, thus at times producing high pressure steam pockets, which overcome the relatively slow velocity of the Water as it moves along the bottom. Vapor locks at these areas occasionally results. The steam in the vapor locked pockets cannot readily release itself and move'or climb upwardly toward the top of the siphon because of the cooler and heavier water above holds it stationary. Thus the interior surfaces of these areas may remain substantially dry and if this condition exists for a considerable period in any one spot, the pressure in the siphon forces the metal in said areas outwardly to produce a bulge or pocket that is visible from the fireside or outer surface of the bulged bottom. The action above mentioned is more pronounced and visible in oil burning locomotives wherein the flames from the burner is concentrated along one or more spots or areas of the bulged bottom. Such action also seems to be more prevalent where the bottom inclination is not so steep, i. e., where the pitch'is not so great.

To overcome this objection without the use of moving parts but by parts that function automatically and continuously in accordance with the natural laws governing steam boiler operation, I provide the following: In the body of the siphon I locate one or more longitudinally spaced upright conduits which extend from a point adjacent the bulged bottom to a point above the open top of the siphon but not above the normal level of the boiler water in the boiler shell. It is desired that each conduit be surrounded by water and therefore tubes 30 are employed as such conduits, the tubes having an outside diameter less than the spacing between the sheets 2| of the body l9. Said tubes are disposed between the staybolts 21 in adjacent vertical rows and the bottom end is preferably bent to face in a direction of the flow of water along said bottom. This arrangement of said end best appears at 3| in Fig. 1. top end of said tube is expanded or belled out- The wardly to increase its diameter as appears at 32 in Figs. 1 and 2. e

To support the tubes in place, I employ clips 33 that are secured to opposite sides of top end portions of each tube and these clips have a hooked engagement with the topmost staybolts of the two vertical rows between which the tube is located. The vertical column outside of and adjacent any given tube is composed of steam and water. There may be steam bubbles of considerable size especially near the bottom. The column within the tube is composed more nearly of water alone. Hence the mean density of the, column of water within the tube is greater than the density of the adjacent steam water column so that an 'overbalancin-g takes place resulting in circulation of water downwardly within the tube.

This action is aided by having the bottom or discharge end of each tube faced away from the direction in which the water normally flows along the bottom. In this instance the tubes are bent toward the rear. There is a sort of aspiratingv action which includes downward flow in the tubes. The water discharging from the bottom of the tubes impinges upon the bottom and breaks up vapor lock so that dry areas cannot develop to bulge or blister outwardly. This action is continuous so long as steam is being made in the boiler and as there are no moving parts, there is nothing to wear out. Therefore, the tubes are good for the life of the siphon without requiring servicing.

By facing the bottom end 3| of the tubes in the direction of the flow of water along the bulged bottom of the siphon, there is also less possibility of steam entering the bottom ends of the tubes.

The tubes in addition to providing means for conveying water downwardly also serve to divide the siphon as a whole into a number of parts thus providing spaced channels which aid in directing the flow of water and steam upwardly. There is thus less conflict of water currents which can impede the free upward flow.

The structure before mentioned is advantageous in that it prevents steam pocket and vapor lock conditions along the bottom of the siphon. The said structure is indeed simple in character and may be provided in a siphon at but a very slight additional cost.

While in describing the invention I have referred in detail to the form, arrangement and construction of the 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 combination with a locomotive firebox including a crown sheet, side sheets, fiue sheets, throat sheet and back sheet, a water steaming and circulating element in the firebox and having an outlet end opening through the crown sheet and having an inlet end opening through one of the other sheets of the firebox and having a bottom portion, and means in said element and extending from a point adjacent said bottom portion to a point adjacent said outlet for conducting boiler water from a point adjacent said outlet end to a point adjacent said bottom.

2. In combination with a locomotive firebox including a crown sheet, side sheets, flue sheets, throat sheet and back sheet, a water steaming and circulating element in the firebox and having an outlet end opening through the crown sheet and having an inlet end opening through one of the other sheets of the firebox and having a bottom portion, and at least one substantially upright tubular member arranged in and approximately surrounded by the water in said element and extending from a point adjacent said bottom portion to a point adjacent said outlet end for conducting boiler water from a point adjacent said outlet end to said point adjacent said bottom portion.

3. In combination with a locomotive firebox including a crown sheet, side sheets, fiue sheet, throat sheet and back sheet, a water steaming and circulating element in said firebox and including a hollow body having an outlet end opening through the crown sheet and also including a downwardly and forwardly inclined bottom that terminates in an inlet neck opening through one of the other of said sheets of the firebox, and means in said body and extending from a point adjacent said inclined bottom to a point adjacent the outlet end of said body for conducting boiler water from a point above said outlet end to a point adjacent said inclined bottom.

4. In combination with a locomotive firebox including a crown sheet, side sheets, fiue sheet, throat sheet and back sheet, a water steaming and circulating element in said firebox and including a hollow body having an outlet end opening through the crown sheet and also including a downwardly and forwardly inclined bottom that terminates in an inlet neck opening through one of the other of said sheets of the firebox, and at least one tubular member arranged in said body and surrounded by the water therein and extending from a point adjacent said inclined bottom out through the outlet end of said body for conducting boiler water from a point above said outlet end to said point adjacent said inclined bottom.

5. In combination with a locomotive firebox including a crown sheet, side sheets, flue sheets, throat sheet and back sheet, a water steaming and circulating element in the firebox and having an outlet end opening through the crown sheet .and having an inlet end opening through one of the other sheets of the firebox and having an upwardly and rearwardly inclined portion between said ends, and means in said element and extending from a point adjacent said inclined portion out through said outlet end for conducting boiler water from a point beyond said outlet end to said point in said inclined portion of said element, said end of said means adjacent said inclined portion being formed to face in direction other than toward the inlet end of said water steaming and circulating member.

6. In combination with a locomotive firebox including a crown sheet, side sheets, flue sheet, back sheet and throat sheet, a water steaming and circulating element in said firebox and including a fiat elongated hollow body having an outlet end and opening through the crown sheet and also including a downwardly and forwardly inclined bottom that terminates in an inlet neck that opens through one of the other of said sheets of the firebox, and a plurality of means arranged in and spaced longitudinally of the body and each extending from points adjacent said bottom out through the outlet end of said body for conducting boiler water from points above said outlet to said points adjacent said inclined bottom.

'7. In combination with a locomotive firebox including a crown sheet, side sheets, flue sheet, back sheet and throat sheet, a water steaming and circulating element in said firebox and including a flat elongated hollow body having an outlet end and opening through the crown sheet and also including a downwardly and forwardly inclined bottom that terminates in an inlet neck that opens through one of the other of said sheets of the firebox, and a plurality of tubular members arranged in longitudinally spacedrelation in said body and surrounded by the water therein and extending from points adjacent said bottom out through said outlet end of the body for conducting boiler water from points above said outlet to said points adjacent said bottom.

8. As an article of manufacture, a water steaming and circulating element for use in a locomotive firebox and including an inlet end and outlet end and an inclined bottom portion between said ends, and means providing a conduit in said element extending upwardly from a point adjacent said bottom portion to a point above said outlet end.

9. As an article of manufacture, a thermic siphon embodying therein a fiat hollow body portion with a downwardly and forwardly inclined bottom that terminates in a tubular inlet neck, the top end portion of the body forming the outlet for said body, and a plurality of substantially upright tubular members spaced longitudinally in the body and terminating at one end adjacent said bottom and terminating at the other end at points beyond the outlet for the body.

10. As an article of manufacture, a water steaming and circulating element for use in a locomotive fireboxand including an inlet end and outlet end and a bottom portion, means providing a conduit in said element extending upwardly from a point adjacent said bottom portion to a point adjacent said outlet end.

11. As an article of manufacture, a water steaming and circulating element for use in a locomotive firebox and including an inlet end and outlet end and a bottom portion, means providing a conduit in said element extending upwardly from a point adjacent said bottom portion to a point adjacent said outlet end, the bottom end of said conduit being faced away from the inlet end.

12. As an article of manufacture, a water steaming and circulating element for use in a 10- comotive firebox and including an inlet end and outlet end and a bottom portion, and a plurality of substantially upright tubular members, spaced longitudinally in the body and terminating at one end adjacent said bottom portion and at the other end adjacent the outlet.

13. As an article of manufacture, a water steaming and circulating element for use in a locomotive firebox and including an inlet end and outlet end and a bottom portion, and a plurality of substantially upright tubular members, spaced longitudinally in the body and terminating at one end adjacent said bottom portion and at the other end adjacent the outlet, the bottomends of said tubular members being faced away from the inlet. 7 r

14. As an article of manufacture, a water steaming and circulating element for use in a locomotive firebox and including an inlet end and outlet end and a bottom portion, and a plurality of substantially upright tubular members, spaced longitudinally in the body and terminating at one end adjacent said bottom portion and at the other end adjacent the outlet, the bottom ends of said tubular members being bent away from the inlet. V

EDWARD J. REARDON.

Images