US1691368A - Car-bottom furnace-hearth seal - Google Patents

Description

Patented Nov. 13, 1928.

UNITED STATES PATENT OFFICE.

JOHN F. BAKEB, OF MANSFIELD, OHIO, A SSIGNOB TO WESTINGH OUSE LECTBIC &i MANUFACTUBING COMPANY, A COBPOBATION OF PENNSYLVANIA.

CAB-BOTTOM FURNACE-HEARTH SEAL.

Application filed June 25,

My invention relates to furnaces and more particularly to 'urnaces of the car-bottom E/P In the usual design of furnaces of the s above-mentioned type, wherein the hearth is removable horizontally from the furnaoe chamber, ditticulty has been experienced in providin r a proper seal between the back wall of t e furnace and the rear edge of the o removable hearth to prevent the loss of heat therebetween.

It has been the practice to so construet the furnace that there is a relatively close fit between the'rear edge of the hearth and the back wall of the chamber when the hearth is in operative position, thereby minin'zing the loss of heat, but, quite obviously, such construction ati'ords only an approximation of the desire'd result.

It is an object of my i'nvention, therefore, to provide a send-seal between the -rear edge of acar-bottom furnace hearth and the back wall of the furna'ce chamber.

A further object of m invention is to provide a seal for the rear ateral ed e of a lon` gitudinally removable learth which shall be automatically operable in response to movements of said hearth.

In racticing ny invention, I provide, in a car-bottom furnace of the usual t pe, having a hearth longitudnally remova le therefrom, a pair of cooperating channels supported u on the rear lateral edge of the hearth and t e furnace wall, respectvely, and adapted to cooperate automatically, as the hearth is moved into operative position, to rovide a seal between the heart edge and urnace chamber wall.

In the drawing:

Figure 1 is a vew, in longitudinal Vertical section, of a furnace embodying my inventiong Fig. 2 is a view, in section. on the line II-II of F ig. 1, and

Fig. 3 is an end elevation of the sand seal shown in Fig. 2.

Referring more particularly to the drawings, a furnace embodying my invention comprises a framework 2, of structural iron, supporting roof and side walls 4 and 6, of sutable refractory material. defining an openbottom furnace chamber 8 having an opening in the front wall thereof to permit the insertion and removal of a movable hearth, as hereinafter described. The opening' inthe 1927. Serial No. 201.420.

front wall isuclosed by a'door 10, inthe usual manner.

A removuble hearth 12, adapted to substantially fill the open bottom of the furnace chamber when in operative position. lsof the usual car type and conprises a refraetory hearth portion 14 nonntml upon a pair of Channels 16 which, in turn, are supported upon fianged wheels 18. Peripherally. of the hearth and extending above the upper face of the hearth portion lut, are refractory walls li'. defining a shallow chamber for the reception 'of electrical-resistance heating elements 18.

The heating elements 18 comprise -sinuously wound electrieal. resistors sup orted upon t e uppcr fai-e of the'hearth'porton 16 within the shallow chamber deined by walls lT.

A Tim-supporting plate. 20, of suitable heat-rcsistant and thermally-conducting inaterial, is peripherall' supported upon the walls '17 ar'l s reinforced intermediate 'its ends by refractory blocks 22 resting upon the upper face of`thc hearth portion 14.

Sand sals of the usual type are provided along the longitudinal edges of the car-bottom hearth (not shown) to prevent the less of heat from the furnace chamber between the hearth and the side walls. An additional send-containing trough 24 is formed on the front edge of the'hearth andis adapted to receive a depending flange 96 on the lower face of the door 10` when the hea'th and the door are -in operative position, to seal the furnace-ehambe' entrance.

Additional means for heating the fnrnace chamber are provided, comprsing sinuous electrical-resistance elements 99 supported upon the side walls thereof. The electrical conneetions for energizing the resistors 28,

as well as resistors 18 on the novable hearth, may be made in any well-known nanner and are thereforc` not shown.

The structure thus far described is common in furnaces of this type. and. since it j forms no part of the present invention. further description thereof is not deemed necessarv.

The means for scaling the rear lateral edge of the hearth conprises` a channel 30. coext'ensive in length with the width of the hearth supported upon the rear lateral edge of the movable hearth, and forming a trough for containing a quantity of granular refractory material. The arrangement is such that, with the hearth in operative position within the furnace chamber, the sand trough s adjacent the back wall thereof and extends substantially the entire width of the chamber.

An inverted channel 34 is pivotally secured to the back wall of the furnace cham ber by means of brackets 36 Secured, at one end thereof, to the face of the channel and journalled, at the other end, on a rod 38 supported by the back wall of the furnace.

The'piv'oted channel 34 is so mounted that, when the hearth is in operative position, a flange 40 tlcrcon depends into the trough formed by channel 30, and the rear flange 42 of the pivoted channel is between the rear flange of channel 30 and the back wall of the furnace chamber.

With the channel in operative position, as described, the rear longitudinal face thereof is jammed against a metal plate 43 embedded in the furnace wall to minimize the clearance between the wall and the pivoted channel 34.

The pivot rod 38 is extended through and beyond the side wall of the furnace, and a weight arm 44 is suitably secured'thereto,

outside the furnace* chamber, to provide a' support for a counterweight 46 adjustably secured thereto. The counterwcight is Secured to the arm 44 at such point that the channel 34 is normally maintained in raised position, as indicated by broken lines in Fig. 3. The downward movement of the counterweight 46 and the consequent upward movement of the, channel 34 are limited by a stop 45 projecting from the side wall of the furnace which limits the movement of the arm 44 downwardly in a vertical direction.

In operation, the door 10 of the furnace chamber is raised or removed to` permit the hearth to be moved into the furnace chamber. As the hearth approaches the limit of its inward movement, the outer flange of the sand trough 30 engages the flange 42 of the channel 34, and, upon continued movement of the hearth, the flange 42 is forced against the furnace back wall, thereby moving the flange 40 down into the refractory material in the sand trough, against the' action of counterweight 46. The rear edge of the hearth is thereby eflectively sealed, and the door 10 may be closed and the heating elements ener ized. r

pou the removal of the hearth, the reverse action takes place. As the hearth moves outwardly, flan e 40 of channel 34 is automatically raised, in response to the action of the counterweight 46, and the sand seal is broken.

While I have shown a car-bottom furnace of a specific type, quite obviously, my invention is applicable to furnaces of any type employing movable hearths. Also, it is clear ly within the scope of myinvention to vary the actual Construction of the sand seal, as well as the sealing material used. For exampc, the channel 30 may be filled with a. plastic or a liquid material, dependng upon the temperature to be attained nthe furnacechamber.

Bymy inventon, I have provided an etficient and automatically operable seal for the:

rear edge of a movable hearth which is positive in operation and rugged in-construction and one that reduces to a minimum the loss of heat theretlrough. i

Va'ious modifications maybe made in my invention without departing from the s irt and scope thereof, and' -I desire, there ore,

that only such limitations shall be placed tlereon as are imposed by the rior art and are set forth in the appended c aims.

I claim as my invention:

1. In a furnace, the combinationwith a furnace chamber and a' car-typehearth removably positioned thei-ein, of a member .of trough shape extending across the rear edge of said hearth and substantiallycoextensive in length with the width thereof and adapt- 'ed to contain a granular refractorymaterial, and a flangecoextensive in len h with said trough and pivotally suppor by the rear wall of said chamber to coo rate with position to form a sand-seal.

2. In a car-bottom furnace, the combineton with a furnace chamber and ahorizon- 'said trough when said hearth is n operative tally removable hearth, of a seal between channel secured to said hearth ada ted to contain 'a quantity of granular re ractory material, and a flae pivotally Secured to said wall and adapt to cooperate with said channel, and means responsive to the movement of said hearth to move said flange into and out' of cooperation with 'said channel.

4. In a car-bottom furnace, the combinati on with a furnace chamber and a hearth removable through the front wall thereof, of

a sand-trough carried by the rear edge of said hearth and a flange carried b the back furnace wall positioned to depen into said trough when said hearth is in operative position, and means o erable upon the movement of said hearth or raisin said flange to permit removal of said hearth.

5. In a furnace, the combinati'on with a 'furnace chamber and a removable hearth therefor, `of co-operatin means on said hearth and a wall of said mace chamber to eonaaa form a seal therebetween, means responsive to the movement of said hearth into said furnace for moving the elements of said sealng means into operative, interlocking relation, and means responsive to the movement of said hearth out of said furnace for moving said elements out ofoperative relation.

6. A mechanical seal comp rsing a laterally movable trongh adapted to contain a refractory material and an nvertecl channel pivoted for lateral movement to cooperate therewith, counterweighted means for biasing said channel out of cooperation with said trough, and means responsive to the movement of said trough toward said channel for I forcing said channel into cooperation ,with said trough to form a seal.

7. In an automatically operable sand seal, a laterally movable sand trough, a pivotally mounted inverted channel having one longitudnal flange thereof adapted to depend into said sand trongh, means .for normally maintaining said flange n raised position out of said trough, and. means whereby, upon movement of sai& trough toward said channel, said flange is forced downwardly into said trough.-

In testmony whereof, I have hereunto subscribed my name this 16th day of June, 1927.

JOHN F. BAKER.

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