US2025266A - Boiler - Google Patents

Description

Dec. 24, 1935.

C. W. BROS BOILER Filed Jan. 22, 1934 INVENTOR 51- a w. BRos ATTORNEYS Patented Dec. 24, 1935 UNITED STATES PATENT OFFICE BOILER sota Application January 22, 1934, Serial No. 707,774

4 Claims.

This invention relates to new and useful improvements in steam boilers, generally, and more particularly to the construction of water circulating tubes to be used in the construction of furnace waterwalls.

In many boilers, particularly those designed for burning pulverized fuel, it is desirable that the walls of the boiler furnace be water cooled. This is usually accomplished by arranging banks of water circulating tubes adjacent to said walls, which tubes are suitably connected in the circulating system of the boiler. These tubes are situated. at the inner sides of the furnace walls, whereby they are directly exposed to the heat of the burning fuel, and, in addition to cooling the walls, they render the boiler more eflicient and economical in operation, because of the increased effective tube area which is obtained.

On Stoker-fired installations, when the furnace 20 walls are thus cooled, the lower portions of the water circulating tubes, or those portions thereof which are disposed in the region of the fuel bed, are usually protected from the intense heat of the burning fuel by suitable firebrick or other means, and also for the purpose of providing a wall having a smooth straight surface along which the fuel may be moved by the action of the usual stoker, or other automatic fuel feeding means which may be employed for supplying fuel to the furnace.

To increase the effective heat absorbing surface of the water walls and to present an all-tube surface to the furnace, it is desirable to eliminate the usual firebrick casing. Heretofore, when the 35 fire brick or refractory material has thus been eliminated from between the tubes to increase the heat absorbing surface of the boiler, tubes have been utilized in the construction of the furnace walls, having longitudinal fins or webs secured thereto. These fins or webs have usually been secured to the tubes at points diametrically opposite thereof, and the fins of adjacent tubes are commonly arranged in overlapping relation to thereby close the gaps or spaces between the tubes.

To use tubes having fins or webs secured to the walls thereof at points diametrically opposite of the tube, causes the inner surface of the furnace walls to be, in effect, vertically corrugated or ribbed. Such construction is quite all right for pulverized fuel or oil fired installations, but not for Stoker-fired installations in close proximity to the stoker. In other words, such construction does not provide each furnace wall with a smooth inner surface, lying in a single plane, along which the fuel may readily be fed or moved by the feeding action of the stoker or power-operated fuel feeding means. Further, such construction does not provide any protection for the front half of the tube which is admittedly 5 necessary on the stoker line. The fiame impingement and abrasion of the sliding fuel bed necessitates protection for the bare tube. It is therefore highly desirable that means he provided whereby the heat absorbing area of the furnace walls may be increased to maximum, and at the same time provide the furnace walls with smooth, plane surfaces, along which the fuel may readily be moved by the fuel feeding means.

The present invention, therefore, concerns itself primarily with the provision of water cooled furnace walls, and more particularly to a novel steam boiler tube unit adapted for use in the construction of furnace walls, and the like, whereby the effective heat absorbing area of the furnace walls is increased to maximum, and is maintained in such condition, and also whereby each furnace wall is provided with a single plane surface along which the fuel may readily be moved.

Objects of the invention are, to provide a boiler 25 tube unit comprising a tubular member or boiler tube having heat conducting members secured to the periphery thereof, which heat conducting members are angular in cross-section, and each being secured to the tubular member in heat conducting relation, at a plurality of points, whereby the heat is quickly transmitted from said members to the walls of said tubular member; to provide a boiler tube having V-shaped heat conducting members secured thereto, and the corresponding adjacent legs of said heat conducting members being disposed in a single plane lying to one side of the tube, whereby said adjacent legs cooperate to provide a single smooth surface; and to provide an improved waterwall for a furnace, comprising a plurality of relatively closely spaced water circulating tubes having heat conducting members secured to the peripheries thereof in heat conducting relation, and in such a manner that portions of said heat conducting members are alined, or, in other words, are disposed in a plane which is offset from said tubes, whereby the inner surface of each furnace wall will have a smooth unbroken heat conducting surface lying in a single plane, whereby the effective heat absorbing area of the furnace wall is increased, with a resultant increase in the efficiency of the boiler.

Other objects of the invention will appear from the following description and accompanying 55 angular cross-section.

drawing and will be pointed out in the annexed claims.

In the accompanying drawing, there has been disclosed a structure designed to carry out the various objects of the invention, but it is to be understood that the invention is not confined to the exact features shown as various changes may be made within the scope of the claims which follow.

In the drawing:

Figure 1 is a perspective view showing a steam boiler tube unit constructed in accordance with my invention;

Figure 2 is a sectional plan view showing the arrangement of the heat conducting members, when the tubes are positioned in a wall;

Figure 3 is a detail sectional view showing a portion of a furnace wall with the invention embodied in the construction thereof; and

Figure 4 is a detail sectional View showing a boiler tube unit having two sets of heat conducting members secured thereto.

The novel boiler tube unit herein disclosed is shown comprising a tubular member or tube 2, of ordinary construction, such as are commonly used in the construction of steam boilers.

To the periphery of this tube, there is secured a pair of heat conducting members 3 and 4, of Each heat conducting member comprises spaced legs 5 and 6, having their extremities or longitudinal edges secured to the peripheries of the tubes 2 in heat conducting relation, by such means as welding, indicated at 'l and 8 in the drawing. The edges of the legs 6 of the heat conducting members 5, are beveled as shown at ID, to obtain a better bond between the edges of said legs and the wall of the tube 2. By thus securing the longitudinal edges of the heat conducting members 3 and 4 to the peripheries of their. respective tubes, they become, in effect, integral parts thereof, and the connections between the heat conducting members 3 and 4 and the tube walls are such as to readily conduct the heat of the burning fuel to the walls of the tubular member 2.

The corresponding legs 5 of the heat conducting members 3 and 4 are disposed in offset relation to the tubular member 2, and, as shown, lie in a plane which is disposed to one side of the tubular member 2, whereby said legs 5 will be alined with one another, as clearly illustrated in the drawing. The other legs 6 of the heat conducting members 3 and 4 are angularly disposed with respect to their complemental legs 5, and are secured to the Walls of the tubular member 2 at points substantially diametrically opposite thereof. By

' thus securing the heat conducting members to the walls of the tube 2, the heat absorbed therein from the burning fuel will be quickly conducted to the walls of the tube 2, where it is'absorbed by the liquid or water circulating through the tubes.

Figure 3 shows a portion of a furnace wall 9 which is lined with a plurality of water circulating tubes 2, having the heat conducting members 3 and 4 thereof alined at the inner side of the furnace wall to provide a straight, smooth surface, along which the fuel fed into the furnace may readily be moved. The spacing of the tubes 2 is such that the heat conducting members 3 and 4 of adjacent tubes are disposed relatively close to one another, small gaps being provided therebetween, as indicated at l I, to allow for expansion of said members. By thus constructing the'furnace walls, the latter are provided with smooth unbroken wall surfaces which function as heat conducting surfaces and transmit the heat from the burning fuel directly to the walls of the Water circulating tubes 2, as will readily be understood by reference to Figures 2 and 3. It is further 5 noted that the tubes 2 are fully protected from impingement of injurious gases and oils such as sometimes occur in oil fired installations.

In actual practice, I have found that the heat conducting members 3 and 4 may readily be 10 formed from angle iron rails, bent into V-shaped forms, as shown, whereby the longitudinal edges of the spaced legs thereof may readily be secured to the walls of the tube 2 in heat conducting relation. Other forms of heat conducting members 15 may be utilized without departing from the scope of the invention, but it is to be understood, that it is of utmost importance that said heat conducting members be so constructed that each is secured to'the periphery of its complemental tube 20 2, at a plurality of different points, and in heat conducting relation, so as to facilitate the transmission of the heat from the furnace to the walls of the tube, and whereby the heat will be more evenly distributed in the tube walls. This will 25 readily be understood by reference to Figure 2, wherein it will be noted that the heat absorbed by the heat conducting members 3 and 4 is transmitted to the walls of the tube 2 at three different points, which increases the efficiency of the boiler and at the same time, prevents overheating or burning of the heat absorbing members 3 and 4.

While I have herein shown the invention applied to the upright walls of a furnace, it is to be understood that it may also be utilized in the 35 construction of a dump grate of a multiple retort stoker, where a'straight, plain grate surface is necessary in order that the burned fuel and ashes may be moved thereover by the feeding action of the stoker. It can also be used in econo- 4O mizers or air preheaters where extended surfaces are highly desirable. In such instances, a double set of angle rails or heat conducting members l2 may be used, as shown in Figure 4. These heat conducting members are shown suitably secured to the periphery of the tube 2, as indicated at [3 and I 4.

I claim as my invention:

1. A boiler wall unit comprising a tubular member, and a pair of heat conducting elements secured to said tubular member in heat conducting relation, said elements each'having two walls disposed at an acute angle to each other, and said elements being positioned on said tubular memher with a wall of each element lying in a common plane and having the marginal edges secured to each other and to the tubular member, and the marginal edges of the other walls of said elements being secured to said member at spaced points thereon.

2. A boiler wall unit comprising a tubular member, and a pair of heat conducting elements secured to said tubular member in heat conducting relation, said elements each having a main wall and an auxiliary wall disposed at an acute angle to each other, said main wall being of a width at least as great as the radius of said tubular member, said elements being positioned on said tubular member with said main walls disposed in a common plane and the marginal edges disposed in abutting relationand in contact with said tubular element and secured thereto, and the marginal edges of said auxiliary walls secured to said tubular member at spaced points.

3. A boiler wall unit comprising a tubular member, and a heat conducting member secured to said tubular member in heat conducting relation, said heat conducting member having a main wall disposed tangent to and secured to said tubular member at the line of contact, said heat conducting member having a width at least as great as the diameter of said tubular member, and auxiliary walls formed by return bends at the outer edges of said main wall, the marginal edges of said auxiliary walls being secured to said tubular member at substantially diametrically opposed lines of contact.

4. A boiler wall unit comprising a tubular member, and heat conducting members secured to said at the outer edges of said main wall, the marginal 10 edges of said auxiliary walls of each pair of members being secured to said tubular member at substantially diametrically opposed lines of contact.

CHESTER W. BROS.

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