US2129057A - Lehr construction - Google Patents

Description

Sept. 6, 1938. 1 F. GREENE LEHR CONSTRUCTION Filed Oct. 3l, 1935 3 She'etS-Sheet 1 ATTORNEY Sept. 6, 1938; J, F. GREENE 2,129,057

LEHR CONSTRUCTXON Filed oct. 31. 1935 5 sheets-sheet 2 NVENTOR J5 SEA/f f/MINE ATTORNEY Sept. 6, 1938. J. F. GREENE I 2,129,057

LEHR CONSTRUCTION Filed oct. 51, 1935 s sheets-sheet 3 ATTORNEY Patented Sept. S, 1938 UNITED STATES LEHR CONSTRUCTION Joseph F. Greene, Vineland, N. J., assignor to Kimble Glass Company, Vineland, N. J., a corporation of Illinois Application October 31, 1935, Serial No. 47,619

4Claims.

This invention relates generally to heating furnaces and has particular reference to a furnace or lehr adapted for the annealing or heat treatlng of glass and similar articles.

One of the primary objects of this invention is to provide an annealing furnace or lehr of the above mentioned character which will include means for efliciently eecting a precise control and distribution of heat within the annealing chamber.

More particularly the invention contemplates the provision of means for simplifying the control of the heat distribution within the annealing chamber to the end that the ware being treated may be brought up to the temperatures desired without the use of a complicated system of temperature control mechanisms.

Numerous other objects and advantages of the invention will become more apparent as the following description proceeds particularly when reference is had to the accompanying drawings wherein Fig. l is a semi-diagrammatic top plan view of a lehr constructed in accordance with the teachings of this invention;

Fig. 2 is a fragmentary longitudinal sectional view through the lehr shown in Fig. l;

Fig. 3 is a horizontal sectional view through the lehr;

Fig, 4 is a transverse sectional view through the lehr;

Fig. 5 is a fragmentary sectional view taken substantially on the line 5--5 of Fig. 3;

Fig. 6 is a fragmentary sectional view taken on the line 6-6 of Fig..3;

Fig. 7 is a perspective view of one of the tiles forming a part of the construction; and

Fig. 8 is a fragmentary perspective view of the floor of the lehr.

Before proceeding with a description of the lehr disclosed in the drawings, it might be noted that the invention is directed generally to the provision of a partition between the source of heat and the ware to be treated, which partition is so constructed that the heat which passes to the ware will be 'accurately controlled and distributed. lA partition constructed in accordance with the teachings of this invention may be incorporated in a lehr fired or heated in any desired manner and the details of construction of the lehr which is about to be described, are therefore not to be construed as definitive of the type of lehr with which the invention may be associated. In other words, while the invention has been shown as being incorporated in a lehr having certain characteristics, it will become apparent as this description proceeds that the invention may be incorporated in a lehr or annealing furnace ofpractically any character whatever.

Referring now particularly to the drawings wherein like reference characters designate corresponding parts throughout all views, there is disclosed a lehr having an annealing chamber ill through which the upper reach of an endless conveyor il extends. The conveyor may conveniently be of the open mesh type and its upper reach may be supported on rollers I2 carried by suitable angle beams I3 which extend longitudinally of the annealing chamber.

, The lower reach of the conveyor may be supported on rollers I4' carried by bearings secured to suitable depending supports l5, while at its ends the conveyor is mounted on suitable drums IB and il. driven in any desired manner, as for example by the belt I8 driven from a suitable source of power i9. It will be understood that the conveyor and its driving and supporting means may be as above described or may be of any other desired character insofar as the conveyor provides means for conveying ware to be treated through the annealing chamber.

'I'he annealing chamber is shown as surrounded by side Walls 20, a roof 2l and a iioor 22. 'I'hese walls, roof and floor of the furnace may be of standard construction, they being preferably formed of brick work and refractory, material, framed, braced and tied together in any desired manner. Likewise the roof of the lehr may be provided with pyrometer blocks 25 in accordance with the usual practice, While at its ends the lehr may be provided with vertical fiues 26 which communicate with the annealing chamber.

Spaced above the floor 22 of the annealing chamber is a horizontally disposed partition or hearth designated generally lby the reference character 30. This partition may be conveniently formed of tiles 3i havingoffset edge portions 32 so that the edges of adjacent tiles will overlap as illustrated in Figs. 4 and 5 of the drawings. At its edges the partition is supported at spaced points from the licor of the annealing chamber by suitable supports 33, while at spaced points centrally of the partition and preferably at the corner of four adjacent tiles, the partition is supported by suitable supports 34.

The spaced relation of the partition 30 vfrom the oor 22 of the annealing chamber provides a tunnel flue or fire box 40 which extends longitudinally of the lehr from the inlet to the outlet The drums il may be conveniently end thereof. The annealing chamber is defined at least in part by the partition 30 which constitutes a surface or wall disposed between the annealing chamber and the re box 40. Fuel is supplied to the fire box by suitable burners illustrated diagrammatically in Fig. 3 and designated by the reference character 4l, there being preferably three of these burners disposed on one side of the lehr and two on the other side thereof. It will be obvious however, that the number and arrangement of the burners may be varied as desired insofar as the desired amount of heat is supplied to the fire box or tunnel.

It will be noted that the longitudinal edges of the partition 30 are spaced from the inner faces of the side walls of the annealing chamber whereby some of the heat from the tunnel flue may pass upwardly around the side edges of the partition and into the annealing chamber I0. A large amount of the heat however passes through the partition and is radiated from the partition to the ware travelling through the annealing chamber on the conveyor I l. The present invention accordingly contemplates the forming of the partition 30 of sections varying in thermal conductivity with the result that heat will be radiated in varying amounts from this partition.

Referring now more particularly to Fig. 3 of the drawings, the first four tiles are designated by the reference character 3l* and under the teachings of this invention these tiles are preferably formed of some material having a relatively low co-eillcient of thermal conductivity such, for example, as alundum. The next ten tiles are designated by the reference character Sib and these tiles are formed of a material having a higher co-eflicient of thermal conductivity such, for example, as carborundum. It might be noted that the thermal conductivity of the tiles of carborundum is about 1.5 times that of the tiles formed of alundum.

'I'he next two tiles are designated by the reference character 3| and these tiles are formed of some high temperature metal whose thermal conductivity is about ten times as great as that of the alundum. The final tiles, designated by the reference character Sid may be formed of cast iron or similar metal.

While it will be understood that the number and arrangement of the tiles may be varied in any manner desired, and that while further thev material of which these tiles are formed may also be varied, in the embodiment of the invention illustrated, the tiles having a relatively low co-efiicient oi' thermal conductivity are disposed adjacent the entrance of the annealing chamber and thus immediately over that portion of the tunnel flue lll which is highly heated by the burners Il. Obviously the use of tiles formed of a material having a. low co-eillcient of thermal conductivity is possible in this section of the annealing chamber by virtue of the high temperature of the tunnel flue M at that point.

'I'he next tiles lib are formed of a material having a higher co-emcient of thermal conductivity so that in the construction illustrated, the ware travelling through the lehr will be sub- Jected to the greatest heat adjacent the last burner Il. Since the heat is somewhat dispelled at points more remote from the burners, the higher thermal conductivity of the tiles Sie and 3|*i permits suilicient heat to pass from the subjacent portion of the tunnel 4l to the ware.

Obviously, if it were desired to obtain a quick rise in temperature and then a sudden drop. the

plates of the greatest thermal conductivity might be placed immediately over the burners and plates of lower conductivity placed over the remaining portion of the tunnel flue. In all cases, however, the tiles may be so arranged as regards the co-eillcient of thermal conductivity of the material from which they are formed that any desired temperature gradient may be obtained within the annealing chamber and this may be accurately controlled without the use of complicated and expensive temperature control mechanisms.

As previously mentioned, it will be apparent that the tunnel flue or fire box may be heated in the manner described or in any other desired manner. Additionally, the lehr itself may be formed in any desired manner and the desired circulation of the heating gases effected in any of the usual ways. Under the teachings of this invention however, there is associated with the annealing chamber a radiating means or partition, sections of which vary as regards their thermal conductivity with the result that the heat to which the ware is subjected may be accurately controlled. Throughout the specification and claims the term lehr" should be construed as meaning the complete construction which includes the heating means, cooling means, if such are utilized, and the means for conveying the ware,.while the term annealing chamber should be construed as meaning the chamber formed within the lehr through which the ware to be annealed is conveyed.

While the invention has been described with some detail, it is to be understood that the description is for the purposes of illustration only and is not definitive of the limits of the inventive idea. The right is reserved to make such changes in the details of construction and arrangements of parts as will fall within the purview of the attached claims.

What I claim as my invention is:

l. In a lehr, an annealing chamber, a heat radiating partition extending longitudinally of said chamber and disposed horizontally thereof, a ware conveyor arranged to advance longitudinally of said chamber above said partition, and means including a fire box disposed below said partition for heating the underface thereof, said partition being formed of three sections, one adjacent the inlet end of the chamber, a second onedisposed intermediately of the chamber, and a third section disposed adjacent the outlet end of the chamber, and the first section being formed of a material of relatively low thermal conductivity, the second section being formed of a material having a thermal conductivity of approximately one and one-half times that of the first section, and the third section being formed of a material having a thermal conductivity of approximately ten times that of the rst section.

3. In a lehr, an annealing chamber, means for heating said chamber, and a partition comprising a plurality of tiles arranged in edge to edge relation and forming a wall of said chamber, said partition being disposed between the said heating means and the chamber, certain of said tiles being formed from a material having a thermal conductivity differing from that of the material from which others of said tiles are formed to radiate more heat into the chamber from certain portions of the partition than is radiated into the chamber from other portions of the partition.

4. In a lehr, an annealing chamber, a heat 15 radiating partition extending longitudinally of said chamber and disposed horizontally thereof, said partition forming the bottom Wall of said chamber, a Ware conveyor arranged to be advanced longitudinally over said partition, and means positioned below said partition for heating the under face thereof, said partition comprising a plurality of tiles arranged in edge to edge relation, certain of said tiles being formed from material having a thermal conductivity differing from that of the material from which others of said tiles are formed to radiate more heat into the chamber from certain portions of the partition than is radiated `into the chamber from other portions of the partition.

JOSEPH F. GREENE.

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