US1477454A

US1477454A - Electric heating furnace

Info

Publication number: US1477454A
Application number: US657775A
Authority: US
Inventors: Seibert Heinrich
Original assignee: Individual
Current assignee: Individual
Priority date: 1923-08-16
Filing date: 1923-08-16
Publication date: 1923-12-11
Anticipated expiration: 1940-12-11

Description

Dec. 11, 1923. 1,411,454

` H. SEIBERT ELECTRIC HEATING FURNCE Filed Aug. 16 1925 Patented Dee. 11. 1923.

"UNITED STATES -Mammun..-

HEI'RCH SEIBERT, GF BERLIN, GERMNY.

ELECTRIC HBA TNG FURNAUE.

Application led August 16, 1925i. Serial No. 657,775.

.To all @claw/tit lmay concern.:

Be it known that I, HEINRICH Salaam', a lcitizen of the German. Republic, residing at Berlin, Germany, have invented certain new and useful Improvements in Electric Heating Furnaces, for which I have filed applications for' patent in Germany, Feb. 16, 1922, and March 8, 1923, and of which the following is a specification.

This invention relates .to electric heating furnaces with granular resistance material. In these electric furnaces, especially in muffle furnaces, amuiile exists around which the resistance material is accommd dated in hollow4 spaces. The use of such inutiles especially in larger sized .furnaces requires corresponding thickness of the wall `even if the muilies are composed ot' several parts. The material from which the muiiies are made, namely, lire brick, is apoor conductor of heat, and consequently is a serious obstacle in the transmission of heat produced in the resistance material to the heat chamber. Especiallyat high temperatures 0ver.l00O C. it therefore happens sometimes that the temperature in the heating spaces is higher by several hundred degrees than the' temperature in the real heating chamber, whereby excessive heat results in the heating spaces and conse uently damaging of the material of the mu e and loss of current. The poor results of such furnaces/f' are mainlyy caused by these inconvenience's. y

According/t0 the invention these inconveniences are avoided by forming the walls of the heating chamber entirely`or partly oit/projecting heating pipes containing ranular resistance material, in order to o tain vthe largest-possible heating surface and to protect at the same time the 'refractory parts. These heating pipes are preferably built in so that they are easily exchangeable and eventually non-supported. The heating pipes may be of convenient cross-section. lf they are of rectangular cross section and if adjacent faces 'oftwo heating pipes are inclined the one to the other the heat is especially well transmitted to the inner chamber'. l. i

In order to prevent a mutual over-heat` ing of the heating pipes they are arranged at a determined distance apart. The air gaps between the heating pipes may extend into the brick work of the furnace. They prevent also the production of short-circuits between the pipes.

The heating started and the material of which/.the furi nace is built is preserved and higher temperatures can be produced with material of equal refractoriness. l

The invention will be best understood from. a consideration ofv the following detailed description taken in connection with the accompanying drawings forming a 'part of this specification, with the understanding" that `while on the drawing several embodi* ments of the invention are disclosed, the in'- vention is not confined to any strict4 con-' formity with the showing of the drawings, but may be embodied in any manner which does not make a material. departure from the salienti features of the invention.

In the drawing Fig. 1 is a vertical cross sectional view of the furnace on line AWB of Fig. 3.

F ig. 2 is a vertical longitudinal sectional. view of the furnace on. line C-Dof Fi 3.

iFig. 3 is a horizontal cross section on ine E-1` of Fig. 1. f

. Fig. 4 Shows in plan View the secondform of construction, the top plate being removed.'

F 5 shows in elevation a single heating pipe.

The'walls of the furnace a consist of refractory material. On the inner Surfaces of the walls heating pipes b', b2 are arranged. The heating pipes o are of trapezoidal cross section. so that the adjacent faces of two heating pipes are inclined with regard to one another, ,the heat being consequent] well transmitted in inward direction. Be-l tween two adjacent heating pipes b air gaps are formed which extend .into the wall a of the furnace and prevent 'a direct contact and a direct transmission of heat from one pipes extend ypreferably through openings in the ceiling of the furlos 'f granular resistance material.

al is inserted through the bottom of the pipe.`

heating pi to the other and consequently also mutua excessive heating of the heating pipes. These air gaps prevent farther the production of short-circuit between the heatl 1n pipes l he heating `ies b are of rectangular cross Sectionan t e heating pipes b2 are of circular cross'section. Inone furnace only heating ipes of the same cross section are preferab y used; but heating pipes of different cross sections might be used, as shown, in the same furnace to ensure radiations of different strengths in the different parts of the furnace.'

In order t improve the Aradiation of the heat' from the walls, this heat having been radiated from the heating-pipes b2 on the walls, the walls have ribeshaped `projections'c. v Y Each hea-ting pipe consists ofl an outer pipe of refractory material being filled with rlhe upper end of the heating pipe is closed by a cap. f through which an electrode d is inserted. This cap may be omitted.

. The neck of thepipe is mounted inthe bottomv of the furnace a the upper-end of the pipe extending through the topr plate g of the furnace. If one of the pipes should be dam-aged it may be removed from the furnace in upward'direetion after the electric connection has been loosened, a new pipe being inserted instead. I i

The bottom is heated by means of resistance material mounted in a cavity-of the bottom, Current is supplied to this resistance material by electrodes d. The resistance material in the bottom is covered by a refractory plate z' whichiprevents the access of air to the resistance material. The opening 7c for the door is closed by a plate Z. In

An electrode "furnace of circular cross section is otherwise -similar to that of the form ,of construction shown in Figs. 1-3.

1 In an electric furnace,v resistance ele- `ments comprising casings of refactory material and granular resistance material. therein, said casings having their llateral faces inwardly inclined whereby wedged shaped air gaps are formed between said resistance elements. n

In an electric furnace, resistance velements comprising casings of refractory material and granular resistance material therev in, said casiugsbeing disposed along the furnace vwalls, and 4air gaps between said casings and extending into the furnace walls.

3. In an electric furnace, resistance ele monts comprising casings of refractory material and granular resistance material therein, said casings being disposed along the furnace walls and having inwardly inclined faces whereby wedged shaped air gaps are `formed between said resistance elements1 said air gaps being extended into 'the furnace walls. p y

In testimony whereof I affix my signature in presence of two witnesses.

HEINRICH SEIBERT. Witnesses:

E. E. KURSCHFURT, E. H. GERMAN.