US1319584A

US1319584A - hopwood

Info

Publication number: US1319584A
Authority: US
Publication date: 1919-10-21
Anticipated expiration: 1936-10-21

Description

J. M. HOPWOOD. FUEL SUPPORT FOR FURNACES.

APPLICATION FILED AUG. I3, 1918- Patented Oct. 21, 1919.

3 SHEETS-SHEET I.

J. M. HOPWOOD. FUEL SUPPORT FOR FURNACES.

APPLICATION FILED AUG, I3. ISII].

Patented Oct. 2t, 1919.

3 SHEETS-SHEET 2- wrm ES'ISE'IS J. M. HOPWOOD. FUEL SUPPORT FOR FURNACES. APPLICATION FILED AUG.I3. I9I8.

1 ,3 1 9, 584;. Patented Oct. 21, 1919.

3 SHEETS-SHEET 3.

gyzawww WWW-mm UNITED STATEENT OFFICE.

JOHN M. HOPWOOD, 0F DORMONT, PENNSYLVANIA, ASSIGNOR TO DARWIN S. WOLCOTT, TRUSTEE, 0F SEWICKLEY, PENNSYLVANIA.

FUEL-SUPPORT FOR FURNACES.

instance,

Specification of Letters Patent.

Patented Uct, 21, 191%.

Application filed August 13, 1918. serial No. 249,729.

To all whom it may concern:

Be it known that 1, JOHN M. Horwoon,

residing at Dormont, in the county of All egheny and State of Pennsylvania, a citizen of the United States, have invented or discovered certain new and useful Improvements in F uel-Supports for Furnaces, of which improvements the following is a specification.

Dilliculty is experienced in the use of the type of fuel supporting surfaces consisting of bars extending in the direction of movement of the fuel in the furnace and spaced to permit of the flow of air between them into the fuel, due to the fact that the bars will grow or increase in dimensions when maintained for a considerable time at high temperatures. When placing these bars in position in the furnace, two conditions which to a considerable extent. are opposed, one to the other, must be reconciled as far as possible, 2'. 6., the bars must be spaced a sufficient distance apart to permit of the passage of air between them in sufficient quantities to support combustion, and on the other hand provision should be made to prevent the sifting of fine coal, ashes, etc., in material quantities between the bars. While these conditions can be fulfilled to a practically efficient degree when the bars are new, the transverse growth of the bars due to continued maintenance at a high temperature will so reduce the spaces between the bars that sufficient air cannot pass between the bars, even if the pressure of air be increased to an undesirable degree, and if the growth is great the bars will contact one with the other requiring greater power to effect their movements.

The invention described herein has for its object the maintenance of spaces of suflicient areas between adjacent members forming the fuel supporting surfaces to insure an efficient supply of the flow of air to support,

combustion at low pressures and at the same time to prevent the slftmg of fine coal and ashes down between the bars and the avoidance of any liability of adjacent bars coming into contact. It is a further object of the invention to provide a regulation of the supply of air for combustion in accordance with the condition of the fuel bed. The in vention is hereinafter more fully described and claimed.

lln the accompanying drawings forming a part of this specification, Figure 1 is a sectional view of the furnace for a boiler havlng my improvements embodied therein; Figs. 2, 3, at and 5 are transverse sections on an enlarged scale, of two main bars and an auxiliary bar and illustrating respectively different forms embodying improvements claimed herein; Fig. 6 is a view partly in side elevation and partly in section of one of the forms of the auxiliary bars; Fig. 7 1s a longitudinal section of the same; Fig. 8 is a View similar to Fig. 1 and having one of the series of bars movable for regulating the supply of air to the fuel bed; Fig. 9 is a detail View showing in sid elevation an auxiliary and a main bar, the former having progressively reduced air feeding grooves;

and Fig. 10 is a sectional view on an enlarged scale the plane of section being indicated by the line X-X, Fig. 8.

While the improvement is shown and described in connection with grate bars having non-connected longitudinal passages with inlets and outlets at the respective ends of such passages, through which the air for supporting combustion flows into the air chambers under the grate bars and up between adjacent grate bars, it will be understood that the improvemcnts claimed herein can be readily used in combination with other forms or types of bars.

in the construction shown, the grate bars 1 are constructed with two longitudinal assages a and 5, each extending approximately half the length of the bars and each provided with openings or ports adjacent. to their ends. These ports are connected with supply chambers and with boxes or chambers 2 below the bars into which the air is discharged after passing through the bars and from whichthe air will flow up through the spaces between the bars.

These bars are supported at their ends and preferably intermediate of their ends by any suitable means and in such manner that the bars if desired may be reciprocated longitudinally to effect the progressive movement of the fuel.

In order to prevent any material amount spaces and overlap the adjacent bars as par-.

ticularly shown in Fig. 5. Although portions of the main and auxiliary bars overlap, provision is made whereby there may be a full free flow of air between the bars and into the fuel bed regardless of the growth of the bars. It will be preferable in most cases to. employ auxiliary bars having webs 4 adapted to extend down between adjacent main bars as shown in Figs. 2 and 3, in

which case the thickness of the. webs and the spaces between the main bars are so proportioned as to afford ample spaces for the upward flow of air. The flow of air between the overlapping portions of the main bars and the bridge or auxiliary bars,

' can be provided for either by so supporting the latter that there may be passages which will not be closed by growth between such overlapping surfaces, or grooves 5 may formed in one or both of such overlapping surfaces. In order that the growth"of the bars forming the fuel supports due to long continued excessive heating, may not detrimentally reduce the air spaces between the webs 4 and the sides of the main bars, grooves 6 are formed in at least one of the adjacent walls of the bars, and preferably in the side walls of the webs 4, the grooves 6 being in alinement with grooves 5 in the overlapping surfaces of the bars. This grooving of one orb'oth of the adjacent faces of the main and auxiliary bars will insure a flow of air into the fuel regardless of any growth. As shown in Figs. 1 and 2, the upper sides of the main bars may be made flat and the bridging or auxiliary bars which bear thereon, projecting above the upper surfaces of such main bars, or recesses 7 may be formed along the edges of the main bars 'for the reception of'the bridging or auxiliary bars, as shown in Figs. 3, 4 and 5. The latter construction will be generally advantageous as the bridging bars may not pro- Qject up into the fuel bed and hence will not be subjected to excessive heating.

It will be observed that fine coal, ashes, etc, mustbefore dropping down between the bars, pass between the bridging and main bars; such movement which will be at an angle to the general movement of fuel and ashes will be prevented by the flow of air outwardly between the overlapping portions of the bars. It will be also observed that air flowing u between the bars, will flow in opposite cirections in thin streams or jets into the fuel, thus assuring a more uniform distribution of the air through the bed of fuel. s

As is well known, the greatest amount of air is required where there is the greatest generation of gases, 2'. 6., adjacent to the point where the fuel is charged onto the grate surface, and that as the fuel is moved through the furnace to the point of discharging the ashes, smaller volumes of air are required. Such a distribution of air may be effected by making the grooves 5 adjacent to the front end of the furnace comparatively large and progressively smaller toward the rear ends of the fuel supporting surfaces as shown in Fig. 9.

In lieu of effecting a proportional distribution of air to the bed of fuel by different dimensions of air passages, such distribution can be effected, by shifting one series of bars forming the fuel supporting means relative to those of the other series, as shown in Figs. 8, 9, and 10. A convenient means for adjusting one series of bars to vary the air supply, consists in connecting the series of bars to be shifted at points adjacent to their front ends, to arms 8 on a shaft 9 arranged transversely of the fuel supporting surface, such connection being conveniently formed by links 10. The rotation of the shaft to raise the movable bars can be effected by any suitable means such as a Worm 11 engaging a worm wheel 12 secured on the end of the shaft projecting outside of the furnace as shown in Fig. 10. The movement of the bars is similar to that of a 1ever having its fulcrum at the rear ends of the movable bars and hence the spaces between the shifted and stationary bars will 7 be greatest at the front of the furnace. In addition to proportioning the supply of air,

the employment of shiftable bars as described will permit of regulating the supply of air to the entire bed of fuel, increasing or decreasing such supply as conditions may require.

In order to prevent fine coal and ashes from dropping between the stationary bars, when the movable bars are reciprocated, the webs 4 are extended sufficiently beyond the heads or bridging bars so as to project under the fore plate of the furnace as shown at 13- in Figs. 8 and 9.

Either one or both of the series of bars maybe reciprocated to advance the fuel along the supporting surface as shown in Figs. 1 and 8. A suitable reciprocating mechanism consists of levers 15 having one end connected to the plungers 16 of the stoking mechanism and their opposite ends isiaee i connected by pitmen 17 to one end of levers 18 which have their opposite ends engaging the main rate bars.

When the series of main grate bars are reciprocated, the bridging or auxiliary bars are held from movemcnt'with the main bars in any suitable manner, such for example as that shown in Fig. l. The webs of the bridging bars which are extended under the dead plate 19 are provided with notches 20 adapted to engage the bar 21 arranged transversely of the furnace under the dead plate.

\Vhen the main bars are reciprocated and the bridging or auxiliary bars are held stationary, as described, the latter cannot be extended onto the curved rear portions of the main bars and hence provision is made for closing the spaces between the main bars beyond the points where the auxiliary bars terminate. A convenient means to that end consists of plates 22 fitting into recesses in the ends of the main bars and bridging the spaces between adjacent main bars. When the bridging or auxiliary bars are reciprocated as shown in Fig. 8, the spaces between the main bars at the rear ends of the latter are closed by filling pieces to prevent the passage of ashes.

I claim herein as my invention:

1. In a furnace the combination of spaced main grate bars extending in the direction of movement of fuel in the furnace and auxiliary bars carried by the main bars and so bridging the spaces between the main bars as to maintain regardless of growth predetermined spaces for the passage of air flowing up between the main bars into the fuel bed and preventing a sifting of fine material into the spaces between the main bars.

2. In a furnace the combination of spaced main grate bars extending in the direction of movementof fuel inthe furnace and auxiliary bars bridging the spaces between the main bars and having portions overlapping and supported by adjacent main bars, adjacent overlapping surfaces being provided with means to insure, regardless of growth, a free'discharge into the fuel of air flowing up between the main bars. m

3. In a furnace the combination of spaced main grate bars extending in the direction of movement of fuel through the furnace, and auxiliary bars bridging the spaces between the main bars and having portions overlapping and supported by. adjacent main bars, adjacent portions of overlapping surfaces being constructed to efi'ect a proportional distribution of air flowing up between the main bars into the fuel,

a. In a furnace, the combination of a fuel support consisting of a'series of grate bars extending in the direction of movement of fuel through the furnace and spaced to permit of the flow of air between them into the fuel, a second series of grate bars adapted to bridge the spaces between the bars of the first series and spaced from the latter to maintain a predetermined minimum flow of air into the fuel in combination with means to shift the bars of one series relative to those of the other series to permit of a flow of air greater than normal into the fuel.

5. In a furnace, the combination of a series of spaced main grate bars and a series of auxiliary bars bridging the spacesjbetween the main bars and so spaced therefrom as to permit of predetermined minimum flow of air into the fuel, means for reciprocating one of the series of bars and means fol-shifting the bars of one series relatively to those of the other series and thereby permit of a flow of air greater than normal into the fuel.

6. In a furnace the combination of spaced main grate bars and auxiliary bars, said bars extending in the direction of movement of fuel in the furnace, portions of the auxiliary bars overlapping adjacent main bars and supported thereby and having portions projecting between the main bars and said bars being so constructed that when arranged in operative relation in a furnace air will flow between the bars and into the fuel supported by the latter.

7. In a furnace the combination of a series of spaced main grate bars extending in the direction of movement of fuel through the furnace and a series of auxiliary bars T-shaped in' cross section alternating with the main bars and supported thereby, adjacent surfaces of one of the series of bars being grooved.

8. In a furnace the combination of a series of spaced main grate bars exmnding in the direction of movement of fuel through the furnace, a series of auxiliary bars bridging the spaces between and supported by the main bars and having portions projecting between the main bars and adjacent surfaces of one of the series of bars being grooved, and means for reciprocating one of the series of bars in the direction of its length.

9. In a furnace, the combination of spaced main grate bars extending in the direction of the movement of fuel through the furnace and auxiliary bars bridging the spaces between the main bars and having portions projecting between the main bars, the main and auxiliary bars having adjacent portions so constructed that spaces of a predetermined minimum capacity for the passage of air into the fuel will be maintained between such adjacent surfaces of the main and auxiliary bars.

10. In a furnace, a series of grate bars having therebetween spaces permitting a maximum growth of the bars while maintaining a predetermined minimum of air spaces and means for bridging the. bar

spaces to prevent material discharge of coal and bridging means being constructed to maintain therebetween, regardless of the growth of the bars, a predetermined minimum of space for the flow of air into the fuel.

In testimony whereof I have hereunto set my hand.

JOHN M. HOPWOOD.