Appeal from the District Court of the United States for the Northern District of Illinois, Eastern Division; James H. Wilkerson, Judge.
Before SPARKS, Circuit Judge, and LINDLEY and BALTZELL, District Judges.
By this action appellant sought injunctive relief and an accounting for damages arising from an alleged infringement of United States patent to Foltz, No. 1,747,822. The patent was issued February 18, 1930, on an application filed January 7, 1924, and was subsequently assigned to appellant. The defenses were invalidity and non-infringement. The court found each of the claims sued upon invalid, and dismissed the bill for lack of invention. From that decree this appeal is prosecuted.
The disclosures relate to furnace construction, and more particularly to that class which has a considerable vertical extent, such as are adapted for the burning of pneumatically fed pulverized fuel for the heating of steam boilers. The state and development of the art here involved, prior to and at the time of the Foltz application, will be quite helpful in appraising his disclosures. They are fairly set forth in Lanyon v. M.H. Detrick Co., 9 Cir., 85 F.2d 875.
The general purpose of the invention is to provide an improved construction of furnace walls which wil possess durability and stability, facilitate installation and repaid, and contribute materially to the efficient operation of the furnace. The particular objects of the invention are to provide a furnace wall of desirable flexibility wherein the refractories (1) are maintained against shifting out of the vertical plane; (2) are not required to carry any great portion of the dead load of the structure, or excessive pressures resulting from thermal expansion; (3) may be installed, removed, or replaced in any limited area without requiring extensive dismantling or removal of those above or without such area; (4) are so arranged as to safeguard them from excessive overheating. Further specific objects are to provide a furnace construction wherein the entire furnace wall may be carried on structural members in such manner that the individual refractories may have a certain amount of independent movement so as to accommodate themselves to contraction and expansion in their own structure and in the furnace structure as a whole, without producing distoring or displacement of the wall, and wherein the supporting structural members are afforded requisite protection from the heat of the furnace; to accommodate admission of air through any selected portion of the walls, and adapted for alteration in that respect with facility; in which a minimum of different forms of refractories and supporting elements are required; in which the strength of the wall supporting members is utilized to the best advantage, so that they may be of minimum weight, the supporting refractories being carried thereon in such manner as to minimize the effect of eccentric loading of the supporting structural elements; which admits of versatility and variety in the design of the furnaces, and will have a great range to use without requiring variation in any of the characteristic details of the construction.
Generally the invention contemplates an external supporting frame made up of structural elements, including posts or columns which are carried on a suitable foundation, and having refractories which form the gas confining walls of the furnace chamber, supported on this frame and maintained thereby in such relationship that they are held against shifting, bulging, and toppling, while they are permitted certain freedom of individual movement so that they may accommodate themselves to changes in temperature without adversely affecting the form of the furnace wall, or its association with other elements of the installation.
The construction comprises column members, which, according to convenience or necessity, may or may not be the boiler columns employed for supporting parts of the boiler installation. These coulmans may be formed of rolled steel members, and may be supplemented at various intervals about the area of the furnace chamber, with other members in the nature of stud columns. These may be carried on the supporting columns by means of stringer beams which are bracketed to the supporting columns adjacent their lower ends. To the vertical frame members or columns are secured the transverse or horizontally extending hanger supports. These may be formed of angle bars bolted to brackets carried by the vertical frame members. Preferably they are uniformly spaced, one above another, and extend in parallel relationship from side to side of the frame structure, presenting, toward the furnace chamber, upwardly wardly directed flanges. These hanger supports constitute retaining supports for the tile retaining members or wall hangers which may be formed of cast iron in the nature of brackets. They have a tension arm terminating in a hook, and a compression arm terminating in a foot. These arms are connected by a bar having lateral marginal flanges. At its lower end this bar and its flanges terinate at a shelf which projects at right angles to the longitudinal dimension of the flanges, and in a direction opposite the compression arm. The speacing of the hanger supports is established with reference to the distance between the hook and foot members, so that when the hook is engaged with the hanger support, the foot will be in cooperative relationship with the inner face of the subjacent hanger support. Each of the wall hangers is adapted to carry a number of slotted refractory tiles, the lowermost of which rests upon the shelf at the lower end of the flanged bar, which lowermost tile is provided with depressions to accommodate the shelf. All of these tiles on any one hanger, except the top one referred to as the key brick, have T-shaped slots, which accommodate the bar of the hanger and its flanges, and when so engaged with and supported on the hanger the tiles and held in alignment vertically, but have a limited amount of individual play on the hanger.
The walls of the furnace chamber are built up of groups of refractories thus supported on the hangers, and these groups are placed in such relationship collaterally that the sides thereof will make contact. Thus there are provided a number of horizontally arranged series of hangers each supporting a limited number of refractories with their sides in alignment. The hangers in vertically adjacent series are arranged in staggered relationship, so that the tile in each series break joints with the tile on those in superjacent or subjacent series. Thus on each of the hanger supports there will be a distribution of the weight of the refractories carried on two of the series of hangers.
The suspension of the refractories on the hangers as thus descreibed permits each hanger and its group of refractories to have a shifting movement relative to those about it, but only in the plane of the wall. Between the uppermost refractories engaged with the flanges of the hangers in one series, and those engaging the shelf of the hanger in the superadjacent series, is inserted one or more unslotted refractories, known as the key brick, and, if desired, a thin layer of compressible refractory material to form an expansion joint. In order to remove and replace any refractory or any one of the hangers, it is only necessary to remove the key brick of such tier, and then remove the slotted refractories by sliding them upwardly beyond the top of the flange.
As a means for controlling external air circulation over the wall refractories and their hangers, the furnace may be surrounded with an outer or sheeting wall of brick which are likewise supported on the hanger supports, whereby the sections of the outer wall thus supported may be removed without requiring dismantling of other sections similarly supported. This gives an air space entirely about the refractory wall, and the admission and circulation of air through it may be controlled by suitable dampers at desired locations. Air may also be admitted into the furnace chamber, by means of air ports, accomplished by the use of narrow refractories spaced apart, at desired points.
Claims 1, 2, 3, 14, 26, 27, 35, 36, 37, 38, 39, 48, 49, 50, 51, and 55 are here involved. Appellee treats claims 14 and 48 respectively as typical of appellant's single and double wall construction. The other claims are set forth in the margin,*fn1 and claims 14 and 48 are as follows:
"14. Furnace construction, comprising in combination, column members, transverse frame members joining said column members to form a self-sustaining frame structure, wall hangers supported on the frame members laterally of said frame structure, refractories carried by the hangers to form independently supported wall sections, said wall sections being associated to form a furnace chamber wall, and certain of said refractories being anchored to their supporting hangers to retain the refractories against displacement inwardly therefrom."
"48. In a furnace structure, in combination, a wall supporting frame disposed laterally of the furnace chamber, a furnace chamber wall comprising sections arranged one above another and each supported independently on said frame, means anchoring said sections against horizontal displacement and a sheathing wall comprising sections ...