US796660A - Fire-door draft-check. - Google Patents

Description

No. 796,660- PATENTED AUG. 8, 1905.

E. B. KIRBY. FIRE DOOR DRAFT CHECK.

APPLICATION FILED JUNE 11, 1903.

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Specification of Letters Patent.

Eatented Aug. 8, 1905.

Appli tion fi1 d June 11, 1903. Serial No. 160,979.

To all whrm it may concern:

Be it known that I, EDMUND B. KIRBY, a citizen of the United States, residing at Rossland, in the Province of British Columbia and Dominion of Canada, have invented a certain new and useful Improvement in Fire-Door Draft- Checks, of which the following is a full, clear, and exact description, reference being bad to the accompanying drawings.

Not a few steam-furnaces are provided with mechanism by means of which the draft appliances are caused to move toward the open or shut position in accordance with the variation between predetermined limits of the steam-pressure in the boiler. The object of such mechanism is to automatically maintain the steam-pressure between such limits by controlling the fire through the draft appliances. It is practically impossible, however, to produce this ultimate result when one employs only the mechanism commonly employed for this purpose, because whenever the fire-doors The present invention relates to mechanismfor accomplishing this purpose which is mainlyuseful in connection with steam-boilers having the automatic regulating device referred to.

The invention may be here summarized as consisting in the construction and combination of parts hereinafter described, and pointed out definitely in the claims.

In the drawings, Figure l is a front elevation of a furnace equipped with my invention in an approved form.- Fig. 2 is a plan View of the same, some of the parts shown in this figure being in section.

Referring to the parts by letters, A represents asteam-furnace of any suitable construction, and B the escape-flue thereof.

C represents the draft appliance, which in the form shown is a damper of the ordinary butterfly variety. It will be understood, of

course, that any other form of damper may be used in place of that shown.

'D D represent the hinged furnace-doors,

extended finger (Z, which enters a slot 6 in a lever-arm e, which turns abouta vertical pivot in substantial alinement with the axis of the door-hinges. This lever is made fast to the lower end of a rock-shaft E, which is rotatably mounted in a box F, secured to the furnace front, and to the upper end of this shaft a cam is secured. The described mechanism is associated with each door.

Gr represents a horizontal bar supported above the fire-doors in boxes J, which permit its endwise movement. In the preferred construction this rod passes through two sleeves H, which are respectively mounted slidably in said boxes, and the sleeves when properly adjusted are rigidly fastened to said bar. The compression-spring M surrounds one of these sleeves and thrusts endwise against the adjacent box and a nut 71 upon said sleeve, and thus acts to move the bar in one direction as far as it is permitted to move. It is stopped from further movement by a shoulder /b on this sleeve and a loose roller K, lying between said shoulder and the box J. This loose roller K is for the purpose of reducing the friction caused by the action of the cam 0 about to be described. Each of these rollers is in engagement with the operating-face of one of the cams e wherefore when either door is opened the associated cam acts against the roller, which transmits its pressure to the shoulder h on said sleeve, and thus causes the sleeve H and bar G to move in opposition to the spring M. Between this bar and the draft appliance there is suitable mechanism which is set in motion by the said movement of said bar, whereby embodiment of the invention shown this mechanism is merely a train of bent levers N and connecting-links N, substantially as shown, the last link in the train being connected to an arm C on the projecting spindle C of the damper. It will be understood, however, that any other mechanism adapted to operate the damper and to be operated or set in operation by the movement of said bar may be substituted for the specific mechanism shown.

The parts are so connected that when the fire-door is opened the damper will be closed, and when the fire-door is closed the damper will be opened by the action of the spring to the fullest extent, provided said damper is only connected with the mechanism described. In certain constructions, however, the same and to each of them is attached an upwardly-.

the draft appliance will be closed. In the damper may be also operatively connected with an automatic regulating device, such as is referred to. In that event the opening of the damper may be independent of the reverse movement of bar G.

Having described my invention, 1 claim- 1. The combination of a furnace, its draft appliance and fire door, a longitudinallymovable bar having a shoulder, a rock-shaft suitably mounted and having a cam thereon for engaging said shoulder, an operating-arm rigid upon said rock-shaft, and provided with a slot, a finger secured to the fire-door and arranged to take in said slot, and mechanism intermediate of said bar and draft appliance, substantially as described.

2. The combination of a furnace, its draft appliance and hinged fire-door, a longitudinally-movable horizontal bar, mechanism intermediate of said bar and the draft appliance, an independent rock-shaft mounted in approximate alinement with the pivotal point of the fire-door, an arm rigidly secured to said rock-shaft and provided with a slot in its free end, a finger carried by the door and arranged to enter said slot, a shoulder fixed against endwise movement upon said bar, and a cam 'carried by said rock-shaft and adapted to engage said shoulder and shift said bar upon the opening of the fire-door.

3. The combination of a furnace, its draft appliance and hinged fire-door, a longitudinally-movable horizontal bar, mechanism intermediate of said bar and the draft appliance, an independent rock-shaft mounted in approximate alinement with the pivotal point of the fire-door, an arm rigidly secured to said rock-shaft and provided with a slot in its free end, a finger carried by the door and arranged to enter said slot, a shoulder fixed against endwise movement upon said bar, a cam carried by said rock-shaft and adapted to engage said shoulder and shift said bar upon the opening of the fire-door, and springs for retaining said bar in normal position.

4. The combination of a furnace, its'draft appliance, and hinged fire-door, with a longitudinally-movable horizontal bar, mechanism intermediate of said bar and draft appliance, a rock-shaft mounted in approximate alinement with the door-hinges, a slotted arm secured to said rock-shaft, and a finger secured to the door and entering said slot, a roller upon said bar abutting a shoulder thereon, a cam engaging with this roller to move the bar in one direction, and a spring operating to move the bar in the opposite direction, substantially as described.

5. In a furnace, the combination with the draft appliance and fire-doors, of a longitudinally-movable bar, mechanism intermediate of said bar and draft appliance, a rock-shaft mounted on the front of the furnace, an arm secured to said shaft and having aslot in the free end thereof, a pin carried by the door to engage in said slot, a roller loose upon said bar but held against longitudinal movement in one direction, and a cam on said rock-shaft and arranged to take against one of the faces of said roller whereby when the furnace-door is opened, said bar Will be shifted and the draft appliance operated, substantially asdescribed.

In testimony whereof I hereunto affix my signature in the presence of two Witnesses.

EDMUND B. KIRBY.

Witnesses:

C. V. JENKINS, C. F. LARSEN.

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