US1798552A - Leer - Google Patents

Description

V. -MULHOLLAND LEER Filed Dec. 27, 1927 m@ ITM 1%@ 1S. Nv. E

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March 31, 1931.

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Inde/'H074 Wwf/Ylo//a//d ky A. 731m Patented Mar. 31, 1931 'VERGIL MULHOLLAND, OF WEST HARTFORD, CONNECTICUT, .ASSIG'NORY TO HARTFORD- EMPIRE COMPANY, OF HARTFORD, CONN ECTICUT, A CORPORATION OF DELAWARE LEER Application filed December 277, 1927. Serial No. 242,877.

This invention relates to leers for glassware, and more, particularly to leers of the type used for baking or fusing a vitreous enamel or other decoration on the ware and nlbsequently annealing it, although the leer as shown and hereinafter described and also various individual features disclosed hereby and-,claimed herein may be useful in the usual annealing of glass where no decorating is to he done.

The process of fusing or baking an enamel decoration on glassware includes first the gradual heating of the ware to a point at which the enamel ork flux used therewith will fuse, then the maintenance of this temperature for the time necessary for the fusion or maturing of the color, and finally the annealing of the ware, that is, the cooling of 1t from this high fusion temperature slowly enough to prevent the introduction of permanent strains to the lower annealing temperature, which is that at which the glass is substantially set and below which no permanent strains will be introduced into the Ware. From this point the ware may be cooled quite rapidly to a temperature at which it may be safely handled for packing or other purposes.

The usual annealing leers as now constructed have. provision for only the annealing and cooling steps of the above process, and one of the objects of the present invention is, therefore, to provide a leer having pro vision for thegradual heating and the maintained heat steps of the process in addition to and yin line with the usual annealing and cooling steps, whereby the entire process may be carried on continuously in a substantially unitary device.

In carrying out the second or maintained temperature step of the process, a fairly high heatis used and at the same time it is necessary to have close control Lof the heat; and for this purpose I preferably employ a specialA type of tire box located in a novel manner with respect to a leer tunnel. of this special fire box yand its location with respect to the tunnel are further oqbjects of the invention.

In handling.. ,certain lof "decorated u ware, especially where the4 sole decoration` is;I

able the maintenance of a The provision adjacent to the top and the ware is lof relatively light weight, difficult-y is sometimes experienced in the ware deforming at the bottom during the time of maintained high temperature, as both temperature and time factors are necessary in the proper maturing of the decoration.

Another object of this invention is, there'- fore, to provide a leer in which the top may be heated to a greater degree than the bottom for the required time, whereby to mature the decoration at the top while the bottom is maintained cool enoughy to present itsv deformation, provision later being made for annealing the' entire article to remove any strains which may have been introduced by such differential heating. If the shape of the Ware makes it advisable, however, the bottoin ma be maintained hotter than the top.

nother object of the invention is to provide for a control of the temperature gradient in the leer by a variation in the amount or velocity of the heating media, While maintaining its initial 'or entering temperature substantially constant.

A further object of the invention is to ensubstantially constant rate of cooling of the ware by the ad@ mission of proper amounts of air into the heating lines, by so proportioning the size and spacing of the air inlets that substantially the same damper setting at cach inlet will give the desired result, thus permitting the proper operation of the leer by comparatively unskilled labor. A t

Other objects and advantages of my invention will appear from the following spec-itication and subjoined claims when taken in connection with the accompanying drawings` '9'0 l in Which: a

Figure l is a diagrammatic vertical longitudinal sectional view of the forward half of a leer embodyi-ng my invention.;

y Fig. 2 is,y a similar View of the'leer shown in Fig.'A 1

of the 'half `Figi-3 is a. section taken substantiallvon .the line 3-3 in Figalftf. f

y.Figi-#Lisv fa section taken?substantiallyon.; j fthefbrokenfline.; 4-g4inf Fig'. 1;? -f

Fig. 5 is a section taken substantially on the broken line 5-5 in Fig. 2;

Fig. 6 is a section taken substantially on the line 6-6 in Fig. 2.

Fig. 7 is an elevation of one ofthe damper members for admitting atmospheric air to the lower tlues having relatively small openings for air admission;

Fig. 8 is an elevation of a damper member having larger openings; and

Fig. 9 is a section on the line 9 9 of Figs. 7k and 8 showing the configuration of the damper members.

Referring to the drawings, the leer tunnel 1 may be constructed ofa plurality of substantially interchangeable sections 2 arranged in end to end relation and suitably supported in any desired manner, as for' eX- ample, tliem'anner shown in my prior Patent 1,560,481, granted Nov. 3,`1925. The ware may be carried through the leer in any suitable maniier, as for example, upon a fiexible wire belt 3 which may be driven by suitable mechanism (not shown), this mechanism preferably being of the type shown in my prior patent above referred to.

c Heating flues 4 and 5 extend vlongitudinally beneath the forward and rear portions of the tunnel respectively and communicate through a passageway 6 with a common fire box 7 ldisposed beneath the leer at a point spaced from the entrance end of the tunnel. The damper 8 controls the passage of the heating `media through the flue 4 from the fire box 7, and the damper 9 the passage of the heating media through flue 5, thus providing for independent regulation of the drafts in these flues. y'Ihe fire box 7 may be provided with one or more suitable burners 10 for oil, gasor other fuel which may be directedthereinto through the opening 11, air to support combustion entering the fire box through the annular space between the buiner 10 and the sides of the opening 11. A desired amount of diluting air may be admitted to the fire box 7 through the passage 12, this amount being controlled by a suitable damper 13. By suitable regulation of the burner 10 and the dampersl 13, 8 and 9, the temperature and volume of the heating gases passing along the flues 4 and 5 respectively, may be controlled. Itis usually desirable to control the temperature of the gases passing from the lire box into lues through the assage 6 within narrow limits, and by suita le control ofthe amounts and velocity of gases passing along the flues 4 and 5, the temperature drop along these iues may be varied at will, as the heat loss through the insulation 14 from the flue 4, and the forward portion of the flue 5, will not vary materially with a change in the velocity of the gases passing therethrough. The flue 4 is provided with an outlet passage 15 adjacent to the receiving end of the tunnel,

Fig. 2, the distances being progressivelyless toward -tlie discharge end of the leer. Instead of this progressive change in the spacing of the passages, or in addition thereto,

the effective area of these' passages 21 may be progressively greater toward the discharge end of the leer, whereby -with a given damper setting, that is, with the dampers in all of the passages 21 opened at a certain given angle, increasing amounts ofcooling air will be admitted per unit length of the tunnel. In practice a convenient way 0faccomplishing this variation using similar parts for economy in manufacture is to provide damper members with' progressively greater openings, but all cooperable with ports of the same size. I prefer to construct the dampers from cylindrical bars and havnov ing eut out segments to permit the passage of air when the bars are rotated to the proper positions. Such bars are shown in Figs. 7, 8 and 9 at 21 and' 21b respectively and are provided with cut out segments 21 of varying length so that the bar 21 may, for eX- ample, be provided with four cut out portions or segments each of two inches length thus providing an aggregate length of eight inches, while the bar 21b may be provided with two cut out segments each of fifteen inches, or an aggregate length of thirty inches. I plan to use bars having progressively increasing total or aggregate cut out lengths or openings toward the exit end of the leer for accomplishing the aforesaid obects. The reason for this` is that it requires ess cooling air to cool the gases a given numv ber of `degrees at a point Where they are `hotter and their total volume is less'than where they are cooler, and the size and dxisposition of these inlets is such that wit the dampers set at a certain angle, the teinperature drop per unit length of tunnel will be constant, so that the rate of coolin of the ware in thetunnel will be substantially constant. This is an important feature, as leers of this character are usually operated by relatively unskilled labor, and in order to have proper operation with dampers and passages of uniform size andv spacing, different damper settings would be re u ired which would require the services of a. s lled operator.

'n The flue 5 communicates through an inclined passage 22 with a header 23, communieating in turn with passages 24, ,one on each I side of the tunnel 1, which lead to a top header or wind box 25 communicating with the fan 20. Thus it will be seen that flues 4 and 5 are at all times maintained at sub-atmospheric pressure, whereby any leaksL in these lilies, as for example, in the joints between contiguous sections 2, will not permit the L combustion products to impinge upon the Ware or cause hot spots in the tunnel, but will only serve to withdraw slight amounts of air :from the tunnel which has no harmful effect.l

The portion 26 formed as a prolongation of the flue 5 to the right of the inclined passage 22 is used to accelerate the cooling ofthe ware and is provided with a dampered air inlet passage 27 adjacent to the discharge end of the leer, cold air from the atmosphere Howing through the passage 27 and to the pas-- sage 22 counter-current to the direction of `motion of the ware.

F lues 28 and 29 extend longitudinally above the tunnel 1 and preferably have a common Wall wit-h the roof of said tunnel in the same manner that ilues 4'and 5 have a Vcommon wall with the Hoor of the tunnel. A

specially designed fire box 30 is interposed between the Hues 28 and 29 and has a common wall 31 with the top of the tunnel. Fire box 30 is provided with a plurality of burners 31 symmetrically disposed with respect thereto, preferably three on each side, these burners being directed into openings 32, similar to the opening 11 in fire box 7 andy having annular spaces as described above to provide for the entrance of primary air'to support combustion. Openings 33 controlled by dampers 34 are provided, preferably one for each of the burners 31 for the purpose of admitting controllable amounts of secondary, and diluting air, the control being similar to that described above in connection with the lower fire box 7.

The flue 28 is provided with one or more outlet openings 35, two being shown, which are controlled by suitablefdampers 36 and which communicate through header 17 and conduits 18 and 19 with the fan 20.

Flue 29 may be provided` with a plurality of dampered air inlet openings 37, two of which are shown, for the' same purpose described above in `connection. with air inlet openings 21. This flue is separated by a suitable dividing wall 38 from a cooling flue 39, to be described. The heating media are drawn off from the flue 29, byone or more suitable passages 40 controlled by dampers 41, the passages; 40 communicating through the conduit 19 with the suction fan 20. Thus it will be seen that the draftjthrough flues 28 4 and 29 is controlled respectively by dampers 36 and 41 in a manner similar to that in which the draft through flues 4 and 5 is controlled by dampers -8 and 9 respectively.

The flue 39 is formedas a prolongation of i the vflue 29 at the cooler end portion of the leer for accelerating the cooling of the ware,

and is open to the atmosphere at the exit end of the leer asl shown at 42. rllhe flue 39 communicates with the conduit 19 through a, plurality of spaced dampered air outlet passages 43 by which the amountofcooling air drawn in a direction counter-current to that of the movement of the ware through the Hue 29, and the distance which it passes may be controlled. c

When used as a decorating leer, the glassware entering the left hand end, as seen in Fig. 1, is at substantially room temperature and is heated at a safevrate by transmitted and radiated heat, and to a lesser extent by convection currents, from the flues 4 and 28 in which the gases flow in a direction countercurrent to the ware, so that by the time the ware reaches a point substantially above the` passageway 6, it has been brought almost to the fusing temperature of the decorating material or the flux used therewith. In the next zone to the front edge of the fire box 30,' the ware will be maintained at a substantially constant temperature, due to the fact that the gases in the iues 5 and 28 are traveling in opposite directions, and thus each tends to balance the temperature drop in the other. In the next zone, that is, immediately under the furnace 30, which is of substantial longitudinal extent and which is of substantially the same Width as the Itunnel, the ware will be maintained again at a substantially constant temperature which may bemaintained 'slightly higher than the temperature in the preceding zone. During the passage through these two zones, the fusion of the decorating material onto the ware takes place. It is necessary to provide a material time for this fusion to take place as well as a certain temperature, so that the odset position of ire boxes 7 and 30 and the longitudinal extent of fire box 30 are both of prime importance. The heating effect on the ware by fire box 30 is still further augmented by the fact that this fire box has a common wall with the roof of the tunnel for substantially its entire vlength and breadth, and the burners 31 therein are symmetrically disposed with respect to the fire box, so that a constant temperature may be maintained.

oration isvall adjacent to the top of the articles and in which the articles are relatively I,

4to an extent likely to cause deformation thereof. The particular type of fire box 30 and its individual control, apart from that of the fire box 7,' is especially adapted for this purpose. .i After the color has been matured on the, ware, either with 4or without di'erential,

, 11'5l In fusing the decoration on certain types` -of ware. namely` that type in which the decheating as described above, it must be an-` nealed to take out any strains which may have been introduced and to prevent the introduction of new strains, and for this purpose a material length or zone in the tunnel is provided, namely that shown in Fig. 1 to the right of the fire box 30, in which zone there are no passages to the flues 5 and 29 for the entrance of cooling air, but the temperature is regulated by the velocity control described above and by the decreasing thickness of the insulation 14. The succeeding zone of the tunnel which may be said to be that portion shown at the left in Fig. 2 to a point near the partition 38 between the flues 29 and 39, constitutes a retarded cooling one in which the ware is slowly cooled to approximately the lower annealing temperature described in the introduction. During its passage from a position under the fire box 30 to approximately the end of this last mentioned zone, the normal rate of cooling of the ware is retarded to permit the permanent strainsv to work themselves out of the Ware and to permit it to be cooled to a point below which they will not be reintroduced. The cooling belowthis temperature may be carried on at a relatively rapid rate. The annealing andcooling portions of the leer to the right, as seen in Figs. 1 and 2 of the fire box 30, are preferably regulated so that all portions of the leer in any transverse section will be maintained at a substantially constant temperature, thus tending to remove any strains which have been previously introduced by differential heating or in any other manner. This accelerated cooling takes place in the succeeding zones, too rapid cooling being prevented in the first part of these zones by carrying the lower flue 5 to a point nearer the discharge end of the leer than the upper heating Hue 29 and depending upon hot convection currents rising from the hot lower. ue and cool currents'falling from the cooler upper yiue 39to govern the rate of cooling of the ware. The final cooling immediately adjacent to the discharge end of the tunnel may be further accelerated by providing the counter-current cold air Hue 26 in addition to `the cooling effect of the top iues 39.

The leer tunnel vused for decorating purposes may well be longer than in the ordinary annealing leer, such as is shown in my prior patent above referredC to, so as to provide the necessary space and time for heating the ware from room` temperature to the fusion temperature of the decorating material and for maintaining it at the high fusion temperature before the annealing is started.

y It should be noted that the top flues 28.29

and B9-are all connected `with the single suction device 2O and are maintained at subatmospheric pressure for the reasons described above inl connectionwith the lower ues 4 and 5.

While I have shown and described but one embodiment of my invention, it is to be understood that many changes might be' to at points spaced from the ware-receiving end of the leer, whereby to provide an initial progressively hotter zone, a zone of maintained heat, and a retarded cooling zone, and

a plurality of cooling lues to provide a final accelerated cooling Zone alongthe path of the ware through said tunnel.

2. A' decorating and annealing leer comprising an elongate leer tunnel, means for conveying articles of glassware therethrough, a plurality of heating iues associated with' said tunnel, means to supply regulable amounts of heating media thereto at points spaced from the ware-receiving end of the leer, whereby to provide an initial progressively hotter zone to bring the ware up to the desired temperature while passing the media in a direction counter-current to the movement of the ware, a zone of maintained substantially constant'temperature controllable by the velocity of the media, and a Zone of progressively decreasing temperature during which the normal rate of cooling of the Ware is retarded while the media pass through said luesn the direction of movement of the ware, and a plurality of longitudinally extending cooling ues'in prolongation of said heating ues and adapted to conduct regulable quantities of atmospheric air in a direction counter-current to the movement of the ware to provide a zonein which the normal rate of cooling of the ware is accelerated,

the leer being materially longer than the usual annealing leers to provide an initial heatingl ing media to said flue intermediate its ends, I

and means for conducting the media from said Hue adjacent to both ends.

means for moving articles of glassware therethrough, a longitudinal heating flue above 4said tunnel, means for supplying heating nov 4. A leer comprising an elongate tunnel, i

hotter zoneand a progressively coolenzone, a cooling Hue formed as a prolongation of said heating Hue at the exit end portion of said tunnel and adapted to conduct cooling media in a direction counter-current to the ware, and means communicating with the ends of said Hues for conducting the various media therefrom.

5. -A leer comprising an elongate tunnel, means for moving articles of glassware therethrough, a longitudinal heating Hue beneath said tunnel, a second longitudinal heating Hue above said tunnel, means for supplying heating media to said Hues intermediate their ends, and means for withdrawing the media from said Hues adjacent to their ends to main-4 tain them at subatmospheric pressure.

6. A leer comprising an elongate tunnel, means for moving articles of glassware therethrough, 'a longitudinal heating Hue beneath said tunnel, a second longitudinal heating Hue above said tunnel, means for supplying heating media to said Hues intermediate their ends, whereby to provide an initially progressively hotter zone and a progressively cooler zone, cooling Hues formed as prolongations of said heating Hues at the exit end portion of the tunnel and adapted to conduct cooling media counter-current to the ware, and means adjacent to the ends of said Hues for withdrawing the various media therefrom to maintain them at subatmospheric pressure..

7. A leer comprising an elongate tunnel, means for moving articles of glassware therethrough, a longitudinal heating Hue above said tunnel, a fire box interposed in said Hue intermediate its ends, and means communicating with said Hue adjacent to its ends for withdrawing the heating media therefrom. a

8. A leer comprising an elongate tunnel, means for moving articles of glassware therethrough, a longitudinal heating Hue 'above said tunnel, a Hre box interposed in said Hue intermediate its ends, means disposed at intervals along said Hue for controllingl the temperatures therein7 and means communieating with said Hue adjacent to its ends for withdrawing the heating media therefrom.

9. A leer comprising an elongate tunnel, means for moving articles of glassware therethrough, a longitudinal heating Hue above said tunnel, a Hre box interposed in said Hue intermediate its ends, a cooling Hue in prolongation of said heating Hue, means disposed at intervals alongeaoh of said Hues for varying the. temperatures therein, and suction means connected to each o'f said Hues adjacent to its `end for withdrawing the variousmedia therefrom. f

10. A leer comprising an elongate tunnel," means for movingarticles of glassware therethrough, a Hue `extending longitudinally beneath said tunnel' through ywhich heating.

media is adapted lto be passed in a direction parallel to the movement ofthe ware, a fire vbox communicating therewith, a Hue extendthe entrance end of said tunnel from the last i mentioned lire` box will conduct the media in a direction counter-current to the direction of movement of the ware, and the remaining portion of said upperl Hue, in the direction of the movement of the ware, and means for withdrawinur the heating media from eac-h of said Hues ad from their respective fire boxes, each of said Hues having ajcom'mon wall with the bottom and; top of the tunnel respectively.

11. A leer comprisin an elongate tunnel, means for moving artic es of glassware therethrough, a Hue extending longitudinally beneath said tunnel, a Hre box communicating therewith intermediate its ends, a Hue ex'- tending longitudinally above said tunnel, a re box interposed therein intermediate its ends, whereby the portions of said Hues toward the entrance end of (said tunnel from said fire boxes will conduct the heating media in directions counter-current to the ware, and the remaining portions of said Hues, in the direction of movement of the ware, means disposed at intervals along portions of said Hues for controlling the temperatures therein, and means for withdrawing the media from said Hues adjacent to their ends distant from their respective Hre boxes.

l2. A leer comprising an elongate tunnel, means for moving articles of glassware therethrough, a Hue extending longitudinally beneath said tunnel, a Hre box communicating therewith intermediate its ends, a Hue extending longitudinally above said tunnel, a fire box interposed therein intermediatel its' ends, whereby the portions of said Hues toward the jacent to their ends distant lict 'entrance end of said tunnel from said ireboxes will conduct the heatingmedia in directions counter-ourrent to the ware, means disposed at intervals along portions of said Hues -for controlling the temperatures therein, cooling. Hues arranged in prolongation of said heating Huesto conduct air Vfrom the exit end of the leer toward the entrance end, and' means for withdrawing the various media from the'ends of said heating Hues adjacent to the entrance end of said tunnel and fromthe remaining Hues adjacent to-the meeting points of the cooling and heating Hues.

13. A leer comprising an elongate tunnel, means for moving articles of lassware therethrough, a longitudinal heating Hue beneath.'

14, A leer comprising an elongate tunnel, i

means for moving articles of glassware therethrough, a longitudinal heating Hue beneath said tunnel, a Hre box communicating with said Hue intermediate its ends, means disposed `at intervals along said Hue for controlling the temperatures therein, and draft impelling means outside said leer communicating directly with said Hue adjacent to both ends thereof.

' extending between said cooling Hue and said conduit.

16. A leer comprising an elongate tunnel, means for moving articles of glassware therethrough, longitudinal heating Hues respectively above and below said tunnel, a fire box communicating with each of said Hues intermediate its ends, the positions of said tire boxes being offset longitudinally of the tunnel, whereby the temperature curve along the tunnel rises to a maximum, has a substan` tiallly Hat portion at said maximum, then tal s.

17. A leer comprising an elongate tunnel, means for moving articles of glassware therethrough, longitudinal heating Hues respeci tively above and below Said tunnel, and a fire box communicating with each of said Hues, the Hre box which communicates with the top Hue being nearer the discharge end of said tunnel than the other of said Hre boxes.

18. lA leer comprising an elongate tunnel, means for mov-ing articles of glassware therethrough, longitudinal heating Hues respectively above and below said tunnel, a fire box communicating with each of said Hues intermediate its ends, cooling Hues in prolongation of said heating Haes, the positions of said fire boxes being offset longitudinally of he tunnel,whereby the temperature Ycurve aloi g the tunnel rises toa maximum, has a substantially Hat portion at said maximum, then falls, and dampered suction means communicating with each of said Hues to withdraw the various media therefrom and regulate the temperatures therein.

19. A leer comprising anY elongate tunnel, means for moving articles of glassware therethrough, a muHie Hrebox substantially the same width as said tunnel and of substantial longitudinal extent associated with said conduction to a uniform high temperature and make a Hat place inthe temperature curve along said tunnel.

20. A leer comprising an elongate tunnel, means. for moving articles of glassware therethrough, and a muliieiirebox substantially the same Width as said tunnel and of substantial longitudinal extent, said lfire box having a common wall with the'top of said tunnel, and a plurality of burners symmetrically disposed in said fire box, whereby to heat a substantial portion of said tunnel byY conduction to a uniform high temperature.

21. A leer comprising an elongate inner tunnel, means for moving articles of glassware therethrough, a longitudinal heating Hue associated with said tunnel, a fire box of substantial longitudinal extent communi- 'eating with said Hue, said fire box having a common wall with said tunnel, and means for withdrawing the heating media from the end of said Hue distant from said Hre box.

22. A leer comprising an elongate inner tunnel, means for moving'articles of glassware therethrough, a longitudinal heating Hue associated with said tunnel, aiireV box of substantial longitudinal extent communieating with saidHue, said fire' box having a common wall with said tunnel, a plurality of dampered air inlet passages disposed at intervals along said Hue, and means for withdrawing the heating media from the end of said Hue nearer the discharge end of said tunnel.

23. A leer comprising an elongate inner tunnel, means for moving articles of glassware therethrough, a longitudinal heating Hue associated with said tunnel, a fire box of substantial longitudinal extent interposed in said Hue intermediate its ends, said Hre box having a common wall Awith said tunnel, and means for withdrawing the heating media from points adjacent to the ends of said Hue.

24. A leer comprising an elongate inner tunnel, means for moving articles of glassn ware therethrough, a longitudinal heating Hue associated with said tunnel, a Hre box of substantial longitudinal extent interposed in said Hue intermediate its ends, said lire boxV and Hue having a common wall with the roof of said tunnel, and means for withdrawing the heating media from points adjacent to the ends of said Hue.

25. A leer comprising an elongate inner tunnel, means for moving articles of glass- -ware therethrough, a longitudinal'heating Hue associated with one wall of said tunnel, a lire box communicating with said Hue, a

disposed at intervals along said Hue, and a Hre box of substantial longitudinal extent having a common Wall with the opposite wall of said tunnel, whereby to permit of differential heating of various portions of the ware during a portion of its travel through said tunnel.

26. Aleer comprising an elongate inner lill' plurality of'temperature controlling means tunnel, means for moving articles of glassware therethrough, a longitudinal heating flue associated with the bottom of said tunnel, a fire box communicating with said flue, a longitudinal heating flue associated with the top of said tunnel, a fire box of substantial longitudinal extent interposed in the n last named flue, the last mentioned fire box having a common wall with the roof of said tunnel, and means connected with said flues adjacent to their ends for withdrawing the various media therefrom.

27. A leer comprising an elongate inner tunnel, means for moving articles of glassware therethrough, a longitudinal heating flue associated with the bottom of said tunnel, a lire box communicating with said flue intermediate its ends, a longitudinal heating Hue associated with the top of said tunnel, a lire box of substantial longitudinal extent interposed in the last named flue, all said lues and the last mentioned fire box having common walls with said tunnel, and suction means connected with said flues adjacent to their ends for withdrawing the various media therefrom. j

28. A leer comprising an elongate inner tunnel, means for moving articles of glass therethrough, a longitudinal heating flue associated with the bottom of said tunnel, a fire box communicating with said flue intermediate its ends, a longitudinal heating flue associated with the top of said tunnel, a fire box of substantial longitudinalextent inter'- posed in the last named flue, means disposed at intervals along said flues for varying the temperatures therein, the positions of said fire boxes being offset to provide a flat portion in the temperature curve of the leer, and suction means connected with said lues adjacent to their ends for withdrawing the various media therefrom.

2S). A leer comprising an elongate tunnel, means for moving articles of glassware therethrough, flues associated respectively with the bottom and toptof said tunnel, a fire box communicating with the bottom flueintermediate its ends, and a second fire box interposed in the topflue, said second fire box being disposed further fromI the ware-receiving end of said tunnel than the first mentioned fire box, and said bottom iue extending toa point nearer the ware-discharging end of said tunnel. than said top flue.

30. A leer comprising an elongate tunnel, means for moving articles ofglassware therethrough, flues associated respectively with the bottom-and top of said tun/nel, a fire box communicating with the bottom flue intermediate its ends, a second` fire box interposed in the top flue, means disposed at intervals along each flue for varying the temper- V aturetherein, said iuesand said sebond fire box having common walls with said tunnel, said second lire box being disposed further from the ware-receiving ends of said tunnel than the first mentioned fire box, and said bottom' flue extending to a point nearer the ware-discharging end of said tunnel than said top flue, and means for withdrawing the various media from points adjacent to the cooler ends of said fiues.

3l. A leer for fusing a decoration adjacent to the tops of glass articles comprising an elongatetunncl, means for moving articles of glassware therethrough, means for progressively and uniformly heating the articles to a point u nder the fusion point of the decorating material adjacent to the entrance end of the tunnel, means in the next succeeding portion of the tunnel for maintaining the tops of the articles at a uniform high temperature for a material time to fuse `and bake 011 the decoration, means opposite said last named means for maintaining the bottoms of the articles at a temperature low enough to prevent deformation, means in the 'next succeeding portion of the tunnel for again bringing theA articles to a uniform temperature throughout to anneal them, and means for cooling the articles at a predetermined rate. 32. A decorating leer comprising an elongate tunnel, means for moving articles of glassware.therethrough, a muflie lirebox substantially the same width as said tunnel and of substantial longitudinal extent associated with said tunnel, and a plurality of burners so disposed Within said firebox as to provide a substantially even horizontal flame distribution therein, whereby to heat a substantial portion of said tunnel by conduction to a uniform hight temperature and make a flat place in the temperature curve of said tunnel.

33. A decorating leer comprising an elongate tunnel, means for moving articles of glassware therethrough, a muifle firebox substantially the same width as said tunnel and of substantial longitudinal extentassociated with said tunnel, and a source of hot Gases so arranged as to distribute the gasessubv place in the temperature curve of said tunnel.

34. A decorating leer comprising an elongate tunnel, means for moving articles of glassware therethrough, a'muffle firebox substantially the same width as said tunnel and of substantial longitudinal extent, said firebox having a common wall with the top of said tunnel, and a plurality of burners so disposed with respect to said firebox as to provide a substantially even flame distribution therein, whereby to heat a substantial portion of said tunnel by conduction to a uniform high temperature 'to mature the decoration on the ware therebeneath.

Signed this 20th day of December, 1927. j VERGIL MULHOLLAND.

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