GB530953A - Improvements in or relating to heat treating furnaces - Google Patents

Abstract

530,953. Electric furnaces, STEVENS, A. H. (Wellman Co., S. K.). July 7, 1939, No. 19832. [Class 39 (iii)] [Also in Group XII] A furnace for the heat treatment of metal articles particularly for welding composite articles by the process described in Specification 530,904, [Group XXII], is provided with a base structure which supports a stack of plate-like articles to be treated, housing means adapted to retain a selected atmosphere in contact with the articles and comprising a container having an upper end wall disposed above the top of the stack and a side wall connected to and extending downward from the end wall to surround the stack, sealing means co-operating with the container side wall for preventing escape of gas from the container, means for applying pressure to the stack through the top wall of the container and means for heating the container. As shown in Fig. 1, the articles g are enclosed in a sealed chamber d<SP>2</SP> supported on the central part a<SP>5</SP> of pan a<SP>2</SP> containing sealing material a <SP>15</SP> into which dips the lower end b‹ of a bell-like housing b<SP>2</SP> the top of which rests on and transmits pressure to the articles through a sealing bell e a block d' and the flexible cover d' of the container d<SP>2</SP>. The housing b<SP>2</SP> is secured to channel members c‹ having guides c<SP>10</SP> which engage with tie rods a<SP>13</SP> secured to fixed channel members a<SP>1</SP> and movable channel members c<SP>8</SP>. An air chamber c<SP>1</SP> is arranged between the channels c<SP>8</SP> and the channels c‹ such chamber comprising upper and lower steel plates c<SP>2</SP> and a flexible rubber wall c<SP>3</SP> lined with canvas. By screwing down nut a" on the tie rods a<SP>13</SP> pressure is transmitted through the air chamber to the housing b<SP>2</SP> and to the top of the articles in the chamber d<SP>2</SP>. The housing b<SP>2</SP> is raised by a hoist attached to the channel members c<SP>8</SP>. The housing b<SP>2</SP> has an electric heating coil b<SP>10</SP> arranged in its inner wall b<SP>9</SP>. During the heat treatment hydrogen is circulated through the container d<SP>2</SP> through pipes d<SP>6</SP>, d' and natural gas is supplied to the space outside the container through the pipe a<SP>10</SP>. In a modification the container d<SP>2</SP> is dispensed with and charcoal is placed upon the charge support to generate carbon monoxide. Fig. 10 shows a further modification in which the electric heating element k" is removably arranged inside the housing.