US2793022A - Regenerative heat exchanger - Google Patents

Description

May 21, 1957 F. w. HARRIS 2,793,022

REGENERATIVE HEAT EXCHANGER Filed Jan. 4, 1954 //v l/E/V TOR. Fo/w W Ham/5 5) HTTORNEKS. HARRIS, K1501, P057226: Hake/s REGENERATIVE HEAT EXCHANGER Ford W. Harris, Los Angeles, Calif., assignor to Wullf Process Company, Huntington Park, Califl, a corporation of California Application January 4, 1954, Serial No. 401,946

Claims. (Cl. 263-51) The invention relates to the economical utilization of heat in any process by the use of regenerative masses. These masses recover and store up heat from waste gases and then give up this heat so that it can be used in the process. Such regenerative masses have a wide use in the steel industry, recovering heat from waste gases and being later used to deliver the stored heat to air to be used for combustion. Such masses are also used in various chemical processes, such, for example, as converting various hydrocarbons to other hydrocarbons by pyrolysis.

The word slab as used herein is limited to a brick or slab which is formed from a heat refractory material such as fire clay, or other ceramic material, or from some metals, graphite, or other carbonaceous materials. The Word refractory is used herein to denote a material which resists injury or decomposition when subjected to heat. The word regenerative as used herein denotes a member or mass which readily absorbs and gives up heat.

A regenerative mass denotes a mass of refractory material which has channels extending therethrough through which gases pass to give up and absorb heat. Such a mass as hereinafter described may be assumed to have the form of a cube.

The invention resides in a novel form of slab which is well adapted to form a new and very useful form of regenerative mass.

The drawings show a portion of or entire, slabs and how these slabs are laid one upon another, in layers, to form a regenerative mass.

Fig. I is a section on a plane shown in dotted lines V-V of Fig. II.

Fig. II is an isometric view of a preferred form of slab.

Fig. III is an isometric view of a partially completed regenerative mass disclosing how the slabs may be laid to break joints and to form slots through which gases may pass and cross channels for equalizing gas flow through the mass.

Fig. IV is a section through a regenerative mass made up of the slabs shown in Figs. I and II, showing how these slabs are laid up to produce two different widths of slot.

The general appearance of the slots as they are seen While being laid to produce the desired regenerative mass is shown in Fig. III, the slabs having a length L, a width W and a thickness T. These dimensions, of course, depend upon the use to which the regenerative mass is to he put and the economical limits imposed by the techniques of tile manufacture, the slabs being produced under such technique.

As shown in Fig. I, the slab 1 has a fairly uniform thickness and has a series of upper grooves 2 and a series of lower grooves 3, these grooves being staggered with relation to each other. The upper grooves 2 are separated by upper bearing surfaces 4 and the lower grooves 3 are separated by lower bearing surfaces 5. All grooves and bearing surfaces are parallel with each other and each ted States Patent 0 Z,793,ll2.2 Patented May 21, 1957 groove is immediately adjacent to a bearing surface which results in fairly uniform thickness in the slab throughout the most of its volume.

A preferred form of slab is shown in the drawings and the preferred proportions of such a slab are shown in Fig. I, the depth of the grooves 2 and 3 being assumed as X. The value of X may be varied but. the preferred proportions will be multiples of X. The depth of the groove being assumed as X, the grooves 2 and 3 may have a width 5X and the bearing surfaces 4 and 5 may have a width of 9X, the thickness of the slab being 3X outside the grooves. For example, the value of X may be about inch, the grooves 2 and 3 being then 1%" wide and the bearing surfaces being 2%" wide and the slab being A" thick. The above dimensions are given merely to illustrate the best mode now contemplated by me of applying the invention. The dimension X may vary widely for different uses but, if the proportions above stated in terms of X are followed, the proportion of voids to solid material in the mass will be between 20% and 25%.

Slabs may be laid as shown in Fig. IV, forming slots 7, each having a depth and a width 5X extending through the mass.

To produce the desired results, the bearing surfaces 4 and 5 must be wider than the grooves 2 and 3. This provides a solid column of material 2X wide along a columnar axis 1112, as shown in Fig. IV, this axis being provided by contact between the bearing surfaces 4 and S. This enables the regenerative masses to be self-supporting if the plane of the slabs is horizontal. It also permits large masses to be built up of slabs having the proportions defined in Fig. IV.

Several objects are accomplished by the novel form of regenerative mass formed by the slabs, among which are the following:

'(a) The slabs are of uniform thickness, which is important in ceramic materials.

(b) The grooves are of relative small depth as compared with their width, for a groove M4" deep in a slab /1" thick would be 1%" wide, which facilitates the'construction of the slab.

(c) The slabs when piled up to form the mass register quite accurately.

Preferably the slabs should be laid as shown in Fig. III in which all joints are broken by using half slabs 20 and full slabs 21, and providing narrow cross channels 22. These channels may be X wide and extend across the mass; that is, they may be about as wide as the grooves 2 and 3 deep. The regenerative masses may be five or ten feet long in the direction of the slots and the slabs may be 9" long (L). A cross channel will then be provided in each layer of slabs every 9". An object of these channels is to provide equalization of flow in all the channels. Each channel connects with all the grooves in each of the slabs bordering the channel and all of the grooves in the bottom of the slabs in the layer above the channel and all the grooves in the top of the slabs below the channel. The cross channels are themselves staggered vertically. In any channel, the better the channel walls, the more resistance to gas flow and each of the channels tends to slow down gas flow when hot and to speed it up when cold. When regenerative masses are used in some processes, the hotter masses, the higher efficiency of the process, and it is highly desirable to heat the mass as close to a destructive temperature as possible; that is, to a temperature at which the material of the slabs starts to spall or otherwise deteriorate. It even a small portion of the mass is overheated, the mass will rapidly deteriorate. The channels 22 prevent such deterioration by providing a uniform heating of the entire mass.

I claim as my invention:

1. A member which may be used to build up a regen erative mass, comprising: a rectangular slab of heat refractory material bounded by two parallel plane surfaces, each of said surfaces havingaseries of parallel fiat grooves each having a Width of at least five (5) times its depth, the grooves on one side occupying intermediate longitudinal positions with relation to the positions of the grooves on the other side, each of said grooves having parallel side walls, and each of said grooves having a length substantially greater than its Width.

' 2. A member as claimed in claim 1 wherein the grooves on each side of said slab are separated from each other by plane surfaces of the slab substantially wider than the width'of the grooves.

3.. A' member as claimed in claim 1 in which the slab has a thickness of about three times the depth of the grooves.

'4. A regeneraative mass consisting of superimposed flat rectangular slabs with horizontal slots in the upper and lower plane surfaces thereof extending from front to back of said mass, each of saidslots being formed by a groove, each of said slots having parallel sides and parallel edges, one side being formed by the bottom of said groove and the other side being formed bythe surface of an overlying or underlying slab, the horizontal width of vide parallel vertical columns of solid material between said slots from top to bottom of the mass.

5. A regenerative mass as specified in claim 4 having narrow cross channels formed between ends of adjacent slabs located in the same plane and extending horizontally across the mass, each cross channel registering with the ends of slots in adjacent slabs located in the same plane,

and also registering with intermediate portions of slots in overlying and underlying slabs.

References Cited in the file of this patent UNITED STATES PATENTS 1,167,081 Kennedy Jan. 4, 1916 1,364,155 Straight Jan. 4, 1921 1,978,191 Porter Oct. 23, 1934 2,473,427 Hasche June 14, 1949 2,622,864 Hasche Dec. 23, 1952 2,706,109 Odman Apr. 12, 1955

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