US1982797A

US1982797A - Stoker furnace construction

Info

Publication number: US1982797A
Application number: US555673A
Authority: US
Inventors: Robert C Denny
Original assignee: MH Detrick Co
Current assignee: MH Detrick Co
Priority date: 1931-08-07
Filing date: 1931-08-07
Publication date: 1934-12-04
Anticipated expiration: 1951-12-04

Description

Dec. 4, 1934. R. c. DENNY STOKER FURNACE CONSTRUCTION Filed Aug. 7, 1931 Patented Dec. 4, 1934 UNITED STATES PATENT. OFFICE Detrlck Company, of Illinois IIL, a corporation Application August '1, 1931, Serial No. 555,673

15 Claims. (CI. 11H.)

This invention relates to the construction of large furnaces, such as boiler furnaces, more particularly to furnaces which are fired by chain grate stokers.

In furnaces which are equipped with chain grate stokers, the sides of the stokers ordinarily are associated quite closely with furnace wall portions, and in most cases it is desirable to have the furnace wall portions overlap the marginal parts of the chain grate. It is desirable to minimize as much as possible the clearance or space between the chain grate and such overlapping wall portions in order to prevent the small fuel from working in between them. At the same time it is necessary that some clearance be maintained, in order that the overlapping wall portions may not drag on the moving grate. Heretofore it has been customary to provide metallic ledge plates along the sides of the stokers, which ledge plates project a suitable distance across the margins of the grate and form supports for superimposed portions of the wall, said ledge plates sometimes being supported on the side frame of the stoker, and sometimes imbedded in and supported on the lower portion of the masonry wall alongside the stoker. The interior wall portions immediately beside the stoker are subjected to erosive and temperature conditions which are likely to wear them out rather rapidly and necessitate their replacement. The ledge plates are also subject to destructive conditions of abrasion and high temperatures and have to be replaced from time to time.

One of the general objects of the present invention is the provision of a furnace structure wherein ledge plates are securely maintained in the desired relationship to the grate and the wall, and at the same time may be quickly and easily removed and replaced without involving the dismantling of any of the associated wall or stoker portions.

Another object is the provision of a construction facilitating the installation, maintenance and repair of the furnace wall portions in association with the ledge plate and stoker and particularly adapted to contribute to the durability of the wall portions and maintain the desired relationship between the wall portions, the ledg plate and the stoker.

Another object is the provision of a construction which will render the stoker and the ledge plates easily accessible from the outside of the furnace and also render the wall and the stoker quite independent of each other in the matter of support.

Another object is the provision of a construction which will permit the weight of the stoker side frame to be reduced.

Another object is the provision of a construction which is particularly adapted to accommodate the wind boxes or plenum boxes of forced draft stokers and minimize the floor area requisite for their installation in conjunction with the furnace.

Other and further objects will be pointed out 85 or indicated hereinafter or will be apparent to one skilled in the art upon an understanding of the invention or its employment in use.

For aid in explanation of the invention I show in the accompanying drawing forming a part of this specification certain forms of construction embodying the invention, but it is to be understood that these are presented entirely for the purpose of illustration and neither they nor the following descriptions of them are to be construed in any fashion calculated to limit the appended claims short of the true and most comprehensive scope of the invention in the art.

In said drawing, I

Fig. 1 represents a part sectional elevation of a0 a boiler furnace having a chain grate stoker, the section being taken transversely of a portion of the furnace chamber and stoker;

Fig. 2 is a detail, on a scale somewhat larger than that of Fig. 1, showing features of the assog5 ciated stoker, wall and ledge plate structure; and

Fig. 3 is a detail in the nature of a horizontal section taken on approximately line 3-3 of Fig. 2.

The nature of the invention will be most readily understood from a description of the illustrative embodiments here shown. The reference numeral 10 designates generally a portion of the furnace chamber, at the lower portion of which is disposed the chain grate stoker, which may be of any of various forms. 11 designates the upper flight, and the reference numeral 11' the lower flight, of the chain grate, which is actuated in any suitable fashion to convey the fuel which is supported as a bed on the upper flight. The reference numeral 12 designates one of the side frames of the stoker, which is supported on a suitable foundation 14 and provided with a ledge 15 which supports a wear strip 16 upon which travels the marginal portion of the chain grate in the upper flight.

On each of the opposite sides of the furnace is disposed a row of upright or column members 1'7, which are spaced apart from one another and connected by transverse frame members 18 which are spaced apart one above another. Hangers 19 110 The reference numeral 95 are supported in rows on the transverse frame members, each hanger having its upper end hooked onto one of said members and having its lower end bearing against the inner side of the transverse member therebelow. Each hanger has a shelf 19 near its bottom portion 'and a bar-like body portion extending upwardly therefrom and provided along its inner margin with laterally extending flanges. Refractories 20 having T- shaped slots at their outer ends are supported on the hangers and anchored thereon by engagement of said hanger flanges in the T-shaped slots. These features of the wall construction are in general such as illustrated and described in U. S. patent to Foltz No. 1,747,822. Refractories supported on the several rows of hangers form wall sections associated one above another and supported independently of one another, to constitute a continuous furnace wall spaced inwardly away from the

frame members

17 and 18 which constitute the wall supporting structure.

To form the wall zone immediately adjacent and above the stoker, a row of hangers 21 is arranged, each hanger having a hook portion 21 at its upper end which is hooked onto one of the transverse members 18, and an outwardly extending arm 21 at its lower end which abuts the inner edge of a transverse member 18', and engages, by a hook, over the inner upstanding flange of said transverse member. The upright portion of each hanger 21 includes a web 21 provided at its inner edge with laterally extending flanges 21 which are offset from one another seriatim. 'I'he hanger has at its lower end an inwardly extending shelf portion 21 which is maintained in a horizontal position when the hanger is supported on the transverse members as above described. The hangers 21 are disposed at intervals, as illustrated in Fig. 3, and each supports a. stack of refractories 22 which are formed at their Outer ends with T-shaped slots which receive the flange portions 21 and web portions 21, whereby the refractories are anchored against displacement inwardly from the hanger. The lowermost refractory rests on the shelf 21 and has a portion depending downwardly across the inner margin of that shelf. The dimensions of the hangers 21 and of the refractories supported thereon are such that the lowermost refractories extend for a distance over the margin of the chain grate 11, and the refractories on juxtaposed hangers are disposed with their lateral sides in abutment so as to form a wall section along and immediately adjacent the stoker grate, the inner face of said section being corbelled outwardly to its junction with the superjacent wall section. The'uppermost course of this corbelled or bottom wall section is made up of refractories 24 which may be of the form and provided with the retaining arrangements illustrated and described in U. S. patent to Sheahan No. 1,767,406. The adjoining portions of the several sections may be constructed in the fashion described in the last mentioned patent, to afford expansion joints which will accommodate the expansion of the several sections independently.

A plurality of ledgeplate sections 25 are provided, same being formed of cast iron or other suitable heat-resisting metal. The respective ledge plate sections preferably are of a length such as to span a plurality of the hangers 21. They preferably are transversely slotted, as at 25*, for a distance inwardly from their inner margins, to afford expansion spaces. These ledge plate sections are disposed end to end in a horizontal series, and are supported on the hangers 21 by means of bolts 26 in the lateral flanges of the hanger arms 21*. Their dimensions and arrangement are such that they extend across the stoker side frame 12 and project a desired distance over the margin of the chain grate 11; where they underlie the lowermost refractories 22 of the bottom wall section. By the employment of shims or washers between the ledge plate sections and the hanger arms 21 as at 27, the ledge plates may be accurately positioned so as to provide exactly the small clearance desired between them and the chain grate. The space between the upper surfaces of the ledge plate sections and the lowermost refractories 22 may be filled with a suitable refractory packing. If desired, the ledge plate sections may be provided with depending flanges 25 which may be abutted against an outwardly presented flange or surface of the stoker side frame in order to form a close joint to prevent gas or air leakage either outwardly or inwardly along the line of the grate.

In various types of forced draft chain grate stokers, wind boxes are provided alongside the stoker or the furnace wall for conveying air under pressure to the space under the upper flight of the grate, said air being introduced below the grate through openings 12 in the stoker side frames. With the present construction such wind boxes may be provided as indicated at 28 immediately alongside the stoker frames andbetween them and the upright frame members 17, and may be made of any light metal, as they carry no Weight.

The construction affords many distinct advantages. The ledge plate sections may be removed and replaced with facility, entirely from the outside of the furnace, and without involving the dismantling of any portion of the wall or stoker. Likewise, the wall portions adjacent the stoker may be removed and replaced without requiring the dismantling of superjacent wall parts and without involving any displacement of the ledge plates. As pointed out above, accurate positioning of the ledge plates with respect to the chain grate is very easily accomplished, and their vertical position may be changed whenever desired or necessary. The stoker side frame is entirely relieved of the weight of the wall or the ledge plate, and consequently may be made appreciably lighter than is necessary in constructions where it is required to carry some of the wall load. Areas adjacent the stoker which are generally occupied by a portion of the wall are rendered available for installation of auxiliary elements of the stoker. The ledge plate is maintained in definite position with respect to the grate, so that their relationship cannot be disturbed by expansion or contraction of the wall refractories or by their distortion or softening from heat. The ledge plates have quite extensive areas exposed to circulation of air outside the furnace, whereby they may be effectively cooled and their rapid destruction by heat avoided.

What I claim is:

1. In a furnace having a chain grate stoker, the combination of a frame spaced laterally from the stoker, a ledge plate supported on the frame and extending over a marginal portion of the stoker, a refractory wall portion supported on the frame independently of the ledge plate and overlying the same to form a protection therefor, and means retaining the ledge plate-and refractory wall portion in association yet permitting their removal independently of each other.

2. In a furnace structure having a chain grate stoker, the combination of a frame spaced laterally from the stoker, a ledge plate supported on the frame and extending over a marginal portion of the stoker grate, refractories supported on the frame above the ledge plate and independently thereof to form a wall portion extending longitudinally of and projecting over a marginal portion of the grate and forming a protective covering for the ledge plate, and means anchoring the refractories and ledge plate in association yet permitting their removal independently of each other.

3. A furnace structure as specified in claim 2 and including attaching members connecting the ledge plate to the frame and disposed in a posisition accessible at the outer side of the wall portion to permit demounting and replacing of the ledge plate from the outside of the furnace.

4. A furnace structure as specified in claim 2 and wherein the ledge plate is associated with the stoker side frame to afford an intermediate channel for travel of the stoker grate and said wall portion overlies said channel.

5. A furnace structure as specified in claim 2 and wherein the ledge plate is formed of sections and the sections are demountable severally from the frame.

6. A furnace structure as specified in claim 2 and including hangers mounted onthe frame to one side of the stoker and forming intermediate connections between the ledge plate, refractory wall portion and frame.

7. A furnace structure as specified in claim 2 and including hangers connected to the frame at one side of the stoker, the refractories and ledge plate being anchored to said hangers, and the hangers holding the refractories and ledge plate spaced away from the frame.

8. In a furnace, the combination with a chain grate stoker and a refractory wall portion overhanging a marginal portion of the stoker grate, of a ledge plate projecting over said marginal portion of the grate and underlying said wall portion, means supporting the ledge plate demountably, and means supporting said wall portion independently of the ledge plate to permit removal of the latter outwardly of the furnace from between said grate and wall portions.

9. In a furnace, the combination with a stoker and refractory wall in overlapping relationship, of a ledge plate interposed between overlapping portions of the two and overlapping a portion of the stoker grate, said ledge plate being secured in position independently of the wall and stoker having extensive surface portions exposed to air circulation outside the furnace chamber.

10. In a furnace having achain grate stoker, the combination of a refractory wall portion overlapping a lateral portion of the stoker and having its inner side in proximity to the chain grate, a ledge plate underlying said overlapping wall portion, and means supporting and anchoring said wall portion and ledge plate independently and permitting removal of either without removal of the other.

11. A furnace structure as specified in claim 10 and including refractory packing material interposed between the ledge plate and overlying refractory wall portion.

12. In a chain grate stoker furnace having a side wall disposed outwardly from a margin of the grate, a series of hangers supported inde pendently of the stoker along the-side thereof, a ledge plate removably supported on the hangers and projecting inwardly across a marginal portion of the grate, and courses of refractories supported by said hangers independently of the ledge plate to form a wall portion having its upper terminus adjoining the lower terminus of said side wall and its lower portion overlying and forming a protective covering for the ledge plate over the grate, the refractories having anchorage on the hangers whereby they are retained in position, and the ledge plate being, removable outwardly from the furnace while the refractories are in place.

13. In a chain grate stoker furnace, in combination, a frame disposed alongside the stoker, a horizontally running series of hangers supported on the frame adjacent the side of the stoker, refractories supported on the hangers and having anchorage thereon whereby they are retained in position to form a lateral retainer for a fuel bed on the grate, and a ledge plate supported on the hangers and extending inwardly over a marginal portion of the grate in juxtaposition to the refractories, said ledge plate being demountable from the hangers and removable outwardly from the furnace while said refractories and grate remain in place.

14. In a furnace having a chain grate stoker,-

the combination of a frame spaced laterally from the stoker, a series of hangers supported on the ROBERT C. DENNY.