US1533270A - Furnace terminal - Google Patents

Description

April 14, 1925.

T. A. REID FURNACE TE-RMINAL Filed Nov. '7, 1922 INVENTOR Thomas/i. Re/c/ ATfORNEY WITNESSES:

Patented Apr. 14, 1925.

THOMAS A. REID, OF WILKINSBURG, PENNSYLVANIA. ASSIGNOIL TO WESTINGHOUSE ELECTRIC 8:; MANUFACTURING COMPANY, ACOBPORATION OF PENNSYLVANIA.

FURNACE TERMINAL.

Application filed November 7, 1922. Serial No. 599,513.

To all 'ZLIlOHL it may concern:

lieit known that I. THOMAS A. Him), a citizen of the United States, and a resident of lVilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Furnace 'lerminals, of which the following is a specification.

My invention relates tofurnaee terminals and particularly to terminals for heating elements or resistors such as are employed in electric furnaces.

()ne object of my invention is to provide a furnace terminal wherein the heat losses due to conduction of the material thereof are reduced to a minimum.

Another object of my invent-ion is to provide a furnace terminal wherein the opening in the furnace wall through which the 20 resistor element extends is effectively sealed for preventing the passage of cool air into the furnace through the said opening; when the temperature of the furnace is redu ed.

Another object of my invention is to provide a furnace terminal having the above cluu'acteristics that may be adjusted longitudinally with respect to the furnace wall and may be free to expand and contract when the temperature of the bar is varied,

Another object of my invention to provide a furnace terminal of such material and design that it may be maintained at sub-- stantially the temperature of the resistor by current therein, regardless of the heat-insulating effect of the furnace wall through which the terminal extends.

Another object of my invention is to provide a furnace terminal wherein the packing for closing the opening through which the terminal extends may readily be replaced and tightened in the event that the packing becomes loose.

These and other objcctsthat will be made apparent throughout the further description of the invention are attained by means of the terminal device herein described and illustrated in the accompanying drawings, wherein- Figure 1 is a vertical sectional view of a portion of a furnace wall upon which a furnace terminal is mounted, and

Fig. 2 is an elevational view of the terminal shown in Fig. 1.

Referring to the drawing the apparatus includes a terminal bar 3 that is preferably made of nickel and to whichv the nichrome resistor or heating element 4 is attached by a welding process, such, for instance, as that described in my co-pending application Serial No. 599,514, filed Nov. 7, 1922. The terminal bar extends through an opening 5 in the furnace wall 6 which is composed of refractory material, such as clay or fire brick, and which is reinforced on the outside by a sheet-metal plate 7 that is provided with an opening 8 alined with the opening 5 in the furnace wall.

The escape of heated. gases from the interior of the furnace or the passage of cool air into the furnace through the opening 5 is prevented by means of a packinggasket. 9 that is of frusto-conical shape and preferably made of asbestos-fiber compound or other refractory material. The gasket is of a pliable nature that may be distorted by compression and forced into contact with the furnace-wall plate 7 and the tern'iirml bar 3 by means of a frusto-conical clamping plate 11 that is attached to the plate 7 by means of screws 12 that extend into threaded holes 13 provided in the reinforcing plate 7. hen the bolts are tightened. the clamping plate 11 compresses the packing gasket. 9 which so intimately engages the bar and plate that heated gases are prevented from escaping. The outer end of the terminal bar 3 is connected to the supply conductor 14 by means of a terminal strap 15 that is secured to the furnace wall by an insulator 16. One of the ends of the strap is provided with a clamping plate 17 of Ushape that surrounds the terminal bar and secure- 1y clamps it to the terminal plate 15 when the clamping screws 18 are tightened. It will be seen from this construction that the terminal bar 3 may be removed from the furnace wall without disturbing the terminal plate. The resistor elements may, therefore, be. removed from the furnace. for inspection or repair simply by releasing the terminal bar 3 from the terminal strap 15 and loosening clamp 11 to permit bar 3 to slide through the bushing 9. The other end of the termmal strap is provided with a terminal clip 19 to which the conductor 14. is connected.

by the heat-insulating furnace wall, the bar is preferably made of nickel which is noncorrosive and offers less resistance than the metal of the resistor element. The bar is so designed that its ctn'rent-carrying capacity bears such relation to the heat insulation of the wall through which it extends that it is maintained at substantially the same tem perature as the resistor.

By reason of this construction, all the heat of the resistor is conserved within the furnace for the reason that none conducted through the terminal bar which is operating at substantially uniform temperature, regardless of radiating conditions surrounding it. This results in a considerable economy of heat within the furnace. If the terminal bar were of such material and design as to'be unheated by the current therein, it would conduct heat from the conductor with a consequent loss of heat in the furnace.

It has been determined that an unheated terminal bar conducts as much heat from the interior of the furnace as several square feet of properly designed furnace wall. It is, therefore, apparent that a terminal bar operating at substantially the same temperature as the resistor results in conservation of heat within the furnace.

While I have described and illustrated but one embodiment of my invention, it will be apparent to those skilled in the art that changes, modifications, substitutions, additions and omissions may be made in the apparatus illustrated Without departing from the spirit and scope of the invention, as setforth in the appended claims.

I claim as my invention: v 1. A furnace terminal comprising a terminal bar adapted to extend through an 0 opening in a furnace wall, a refractory gasket surrounding the bar and a gasket clamp for pressing the gasket into contact with the wall surrounding the said opening and the terminal bar.

2. A furnace terminal comprising a terminal bar adapted to extend through an opening in a furnace wall, a refractory pliable gasket of frusto-conical shape surrounding the bar and a gasket clamp corresponding in shape to that of the gasket for pressing the gasket into contact with the wall surrounding the said opening and the terminal bar.

3. A furnace terminal comprising a terminal bar adapted to extend through an opening in a furnace wall, a packing gasket surrounding the bar and engaging the wall of the furnace for preventing the passage of gases through the said opening means for adjustabl-y clamping the to the furnace wall.

4. A furnace terminal comprising a longitudinally movable terminal bar adapted to extend wall, a gasket surrounding the bar and engaging the wall for preventing the passage of gas through the said opening and a conductor strap insulated from, and supported gasket by, the furnace wall and having a terminal- 1 bar clamp thereon for permitting longitudinal adjustment of the bar with respect to the clamp when the clamp is released.

In testimony whereof, I have hereunto? subscribed my name this 25th day of October, 1922.

THOMAS A. REID.

and a 7 through an opening in a furnace 7

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