US2194098A - Steam boiler - Google Patents

Description

March 19, 1940. G. A. REHM STEAM BOILER Filed'July 28, 1938 60:24 VA REHM O I. QM .o o o I 2 o M o u 2 T 0 V 2 Patented Mar. 19, 1940 UNITED STATES PATENT orrics STEAM BOILER Application July 28, 1938, Serial No. 221,664

5 Claims.

This invention relates to steam boilers, and more particularly to boilers of the water tube typ One common form of water tube boiler comprises a transverse lower water drum from which a bank of steam generating tubes extends upwardly across the path of flow of the furnace gases, and in many instances water wall tubes have been connected at their upper ends to this drum. These water, wall tubes discharge large quantities of steam into the drum, and in some cases the rapid circulation of water through the drum has carried much of this steam into the steam generating tubes to mingle with the steam which is produced therein, causing such a congestion in these tubes as to block the circulation through them. Consequently the tubes have become overheated and damaged so seriously as to require replacement. These facts have been recognized and it has been proposed heretofore to installconnecting tubes inside the drum between the upper ends of the water wall tubes and the lower ends of certain of the steam generating tubes which are swept by gases of comparatively low temperature. These connecting tubes are difiicult to install or remove, they form a serious restriction to the circulation of water through the drum, and they prevent access to the ends of the steam generating tubes and water wall tubes. I

It is accordingly one object of the'invention to provide an improved means for conducting steam from water wall tubes through the lower drum of a boiler without unduly restricting the circulation of water through the drum.

I It is a further object of the invention to provide an improved steam conducting means which can be readily installed in the lower drum of a boiler and easily removed therefrom, and which will not prevent access to the tubes connected to the drum.

With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts sets forth in the specification and covered by the claims ap-,

The embodiment illustrated comprises a transverse upper steam-and-water drum Ill and a transverse lower water drum H located beneath the drum I and connected thereto by a bank of upright, water tubes l2. A bank of water tubes M extends upwardly and forwardly from the front portion of the drum H to an upper water drum [5 which is connected to the steamand-water drum H) by a bank of upwardly and rearwardly sloping water tubes IE. A row of tubes IBeXtends forwardly from the drum ill to a steam drum l9 located above the water drum l5. These tubes l8 support the roof 2!) of the boiler. Beneath the tube bank Hi there is provided a combustion'chamber 22 having a front wall 23, a rear wall 2 and side walls 25. A wall 21 is provided in the rear of the tube bank l2,

' with a gas outlet 28 between the upper portion of this wall and the steam-and-water drum ll].- Suitable balfies 29 are installed to direct the hot gases from the combustion chamber 22 into con tact successively with the tube banks l4, l6 and i2, and thence to the outlet 28 in a well-known manner.

A row of upright water wall tubes is associated with the rear wall 24 to support this wall and protect it from the heat of the combustion nected to the lower front portion of the water drum H, beneath the tubes Hi, and in order to maintain adequate ligaments in the drum the ends of the tubes 3b may be staggered as shown in Figs. 3 and 4. The lower ends of the water wall tubes 30 are connected to a horizontal header3l to which water is supplied from the drum ll through a row of downcomer tubes 32 located in the rear of the tubes 38.

It will now be apparent that with the construction as so far described there will be a rapid circulation of water from the drum Ill downwardly through the tubes 1 2, thence forwardly through the drum I l and the tubes M to the drum l5, and thence rearwardly through the tubes IE to the drum ill. The steam which is generated in the tubes I4 and IE will be carried along with the water and released in the drum IE3, whence it will flow through the tubes It to the drum l9 and from this drum to a place of use. Large quantities of steam will be generated in the water wall tubes 38 and discharged upwardly into the drum H, and the rapid forward circulation of water through this drum may sweep this steam into the water tubes I4 to mingle with the steam which is being generated in these latter tubes. This may cause so much congestion in the tubes M as to chamber. The upper ends of these tubes are conprevent adequate circulation therethrough, and the tubes may be seriously overheated. This is particularly true of the tubes in the lowermost row, which are subjected to intense radiant heat.

In order to avoid this difiiculty I provide an improved baffling means 34 in the interior of the drum I l to direct the steam away from the lower rows of tubes 14 and into tubes which are remote from the water wall tubes in a direction circumferential of the drum. This steam is preferably directed into certain of the tubes l2, thus causing these tubes to serve as upcomers which conduct the steam upwardly to the upper drum H]. For this purpose I mount within the drum II a plate 35 which slopes upwardly and rearwardly above the upper ends of the water wall tubes 30. The front or lower edge of this plate is located between the tubes 3!! and the lowermost of the tubes [4. For convenience in installing and removing this plate, its front edge portion may be bolted to a strip 36 which is welded to the interior of the drum wall. The bottom surface of the plate 35 is provided with depending ribs 38 which converge in pairs in the rearward direction. Steam flows upwardly from the tubes 30 to the plate 35 and is thereby compelled to flow rearwardly, the ribs 38 serving to concentrate this steam into several separate streams. These streams are directed upwardly into certain of the tubes l2 which lead directly to the drum l0, and for this purpose I preferably utilize a series of conduits in the form of channel members 39 which are spaced apart from each other in a direction longitudinal of the drum. These channel members are open toward the rear, and they slope upwardly and rearwardly at a steep angle from the rear edge of the plate 35. Their lower ends may be bolted to the plate, and their upper ends may be bolted to a strip 40 which is welded to the interior of the drum wall between the tubes l2 and M. It will be noted from Fig. 4 that the upper end of each channel member 39 is located directly beneath one of the tubes I2, and that the lower end of each channel member is located between two of the converging ribs 38.

t will now be apparent that in the operation of the boiler there will be a rapid circulation of water downwardly from the lower drum H through the downcomer tubes 32 to the header 3! and thence upwardly through the water wall tubes 39. These tubes fill will discharge large quantities of steam into the drum, and this steam will rise through the water until it encounters the plate 35 and thence will travel upwardly and rearwardly along the lower surface of the plate. During this rearward travel the steam will be directed by the inclined ribs 38 into several concentrated streams which are spaced apart in a direction longitudinal of the drum, and these streams will flow upwardly through the channels 38 into the tubes l2 thereabove which lead directly to the steam-and-water drum Hi. Because of the comparatively wide spacing between the channels 39 there is ample area for the normal circulation of water forwardly through the drum H to the lower ends of the water tubes M, and the bafile construction will prevent this water circulation from carrying any of the steam into these tubes. The baffles are simple and inexpensive to manufacture and they allow ready access to the tubes for cleaning purposes.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A steam boiler comprising a horizontal water drum, downcomer water tubes connected at their lower ends to the drum, upcomer water tubes connected at their lower ends to the drum, a row of water wall tubes connected at their upper ends to the drum and arranged to discharge steam into the drum, and bafile means spaced above the upper ends of the water wall tubes and arranged to concentrate the steam discharged by the water wall tubes into streams spaced apart longitudinally of the drum and to direct said streams into certain of the upcomer tubes, the downcomer tubes serving to deliver water to the drum which flows between the said concentrated streams of steam and thus to upcomer tubes on the other side of said streams.

2. A steam boiler comprising a horizontal water drum, downcomer water tubes connected at their lower ends to the drum, upcomer water tubes connected at their lower ends to the drum, 2. row of water well tubes connected at their upper ends to the drum and arranged to discharge steam into the drum, baffle means spaced above the upper ends of the water wall tubes and arranged to concent-rate the steam discharged by the water wall. tubes into streams spaced apart longitudinally of the drum, and spaced conduits to direct said streams upwardly into certain of the upcomer tubes, the downcomer tubes serving to deliver water to the drum which flows between the said conduits and thus to upcomer tubes on the other side of said conduits.

3. A steam boiler comprising a horizontal water drum, downcomer water tubes connected at their lower ends to the drum, upcomer water tubes connected at their lower ends to the drum, 2. row of water wall tubes connected at their upper ends to the drum and arranged to discharge steam into the drum, bafile means spaced above the upper ends of the water wall tubes to deflect the steam discharged by the water wall tubes and including depending ribs which converge in pairs in the direction of flow to concentrate the steam into streams which are spaced apart longitudinally of the drum, and spaced conduits to direct said streams upwardly into certain of the upcomer tubes, the downcomer tubesserving to deliver water to the drum which flows between the said conduits and thus to upcomer tubes on the other side of said conduits.

4. A steam boiler comprising a horizontal water drum, a plurality of rows of water tubes connected to the upper portion of the drum and extending upwardly therefrom, means to direct hot gases into contact with the water tubes, a row of water wall tubes connected to the front side of the drum below the water tubes and arranged to discharge steam into the drum, bafile means spaced above the upper ends of the water wall tubes to deflect the steam rearwardly and including depending ribs which converge in pairs in the rearward direction to concentrate the steam into streams which are spaced apart longitudinally of the drum, and upwardly extending conduits arranged to di ect said streams into certain of the water tubes which are remote from the water wall tubes in a direction circumferential of the drum.

5. A steam boiler comprising a horizontal water drum, a plurality of rows of water tubes connected to the upper portion of the drum and extending upwardly therefrom, means to direct hot gases into contact with the water tubes, a row of water wall tubes connected to the front side of the drum below the water tubes and arranged to discharge steam into the drum, an upwardly and rearwardly sloping plate spaced above the upper ends of the water wall tubes to deflect the steam rearwardly, ribs depending from the plate and converging in pairs in the rearward direction to concentrate-the steam into streams which are spaced apart longitudinally of the drum, and

channel shaped members open toward the rear and sloping upwardly and rearwardly to direct said streams 'into certain of the Water tubes'which are remote from the water Wall tubes in a direction circumferential of the drum.

GUSTAV A. REHIVI.

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