US1754193A - Apparatus for annealing glassware - Google Patents

Description

April 8, 1930. T. WARDLEY ET AL APPARATUS FOR ANNEALING GLASSWARE Filed June 21, 1928 s Hm n m r h S I my h m @7 M L o no. H x ,m w m N m- H m Q S & Afi E J. v m M. x m MN E G m m /3 0d Patented Apr. 8, 1930 UNITED STATES PATENT OFFICE THOMAS WARDLEY, OF GREEN FORD, AND HAROLD V. E. M. RENN, OF WEST EALING,

ENGLAND, ASSIGNORS TO HARTFORD-EMPIRE COMPANY, OF HARTFORD, CONNECT- ICUT, A CORPORATION OF DELAWARE APPARATUS FOR ANNEALING GLASSWABE Application filed June 21, 1928, Serial No. 287,201, and in Great Britain .Tune. 29, 1927.

5 flue or flues or the like adjacent to or in close proximity'to a chamber, tunnel, or the like, through which are passed the articles or ware to be annealed. The invention has more particular, though not exclusive, reference to lehrs in which the articles are carried through the chamber, tunnel, or the like, on an endless conveyor constituted by a flexible band of heat resistant material, such as flexible openwork or mesh fabric, that travels in contact with or in close proximity to a smooth surface of a plate or the like that may form the upper part of the flue through which the hot gases or products of combustion pass, preferably at sub-atmospheric pressure. The articles in passing through the lehr are first subjected to a uniform or approximately uniform temperature for a predetermined period during which they are allowed to gain temperature uniformity prior to the commencement of the cooling procedure for which latter there is a gradual and slight decrease in the temperature until a certain stage is reached, thereupon the rate of temperature drop is greatly increased to effect rapid cooling of the articles .01 ware.

An object of the present invention is to enable an increase in the temperature of the lehr tunnel to be brought about when required without necessarily increasing the amount of heat initially applied to the lehr. It is well known that the greater the speed of hot gases flowing along the flue consequent, for example, upon a smaller cross section of the flue, the higher will be the temperature on the side heated by the as with a resulting increase in the amount of heat transmitted. We apply this principle to lehrs and our invention consists in so designing the flue or passage for the hot gases or other temperature controlling medium that a greaterrate of heat transference from the flue to the tunnel or chamber containing the articles or Ware can be effected at any desired section or sections of the lehr.

According to this invention, the flue or paseffected at the initial or gradual cooling stage,

so that temperature conditions can be varied according to requirements. For instance, when the weight of the ware being annealed per unit of time is comparatively small, it may be'desirable to raise the temperature at the lower end of the critical annealing stage to the temperature obtained in the corresponding zone when the weight of the ware being annealed per unit of time is substantially greater. This is accomplished by gradually reducing the cross sectional area of the flue at the required position without varying the surface area of the part through which heat is transferred to the interior of the tunnel, so that the velocity of the hot gases passing through the restricted portion of the flue is increased, with the result that there is an increased heat transference between the gases and the interior of the tunnel. Means may be provided whereby the said increase in the heat transference may be controlled, so that the temperature environment in the lehr tunnel can be regulated accordin to requirement. For example, the transmission of heat may be decreased at the section where provision is made for the increased heat transference by the admission of cold air, to bring about the required reduced temperature environment in the lehr, or this may be effected by adjustable means which permits of variations in the cross sectional area, for example, by the use of an adjustable elongated damper, vanes or the like in aflue which is normally of constant or uniform cross sectional area.

We have chosen to illustrate our invention in connection with a lehr of the general type shown by the patents to Mulholland Numbers 1,560,481, granted Nov. 3, 1925 and 1,571,137, granted Jan. 26, 1926, each of which shows a lehr having an elongate tunnel, means for conveying articles of glassware therethrough, a heating flue or flues beneath the tunnel and extending longitudinally thereof with suitable controls at spaced intervals therealong and a cooling flue or flues extending longitudinally above the tunnel from the cooler or exit end material portion of the length of the tunnel and having suitable controls at spaced intervals thereon for controlling the cooling action.

Our present invention contemplates a method of annealing glassware in which the ware in the tunnel is carried through zones of progressively changing temperature and in which the temperature gradient along substantially the entire length of the lehr may be controlled at will. The present invention includes, in addition to the control shown and described in connection with the Mulholland patents, the idea of varying the temperature gradient in the tunnel by varying the rate of heat transfer between the ware therein and the gases in a temperature controlling flue by varying the velocity of such gases in a predetermined zone or zones.

In order that the said invention may be clearly understood and readily carried into eifect, the same Will now be described more fully with reference to the accompanying drawings in which;

Figure 1 is a vertical section of a lehr embodying the present invention;

Figs. 2 and 3 are transverse sections on= the lines II, II and III, III in Fig. 1 respectively; and

Fig. 4 isa fragmentary longitudinal sectional detail view showing an alternative arrangement.

.Referring to Figs. 1, 2 and 3, the lehr is formed with a flue 2 having a permanent gradual decrease in cross sectional area formed by a bottom plate or wall 3 which is inclined upwardly in the direction of flow of the hot gases from a fire box 4. The surface area of the upper part 5 of the flue through which the heat is transmitted to the interior 6 of the lehr tunnel, in which are positioned the ware or articles to be annealed, is shown as uniform throughout the length of the flue and is not reduced in reducing the cross sectional area of the flue itself as indicated in the sectional views, Figs. 2 and 3.

In order that there may be a gradual return to the normal or'full cross sectional area of the flue from the position where the area is reduced, an additional plate or wall 7 is provided which is inclined in the opposite direction to that of the plate 3. The length of the additional plate 7 measured in a direction longitudinally of the flue is less than that of the plate 3, but the ratio of their respective lengths may be as desired, dependent upon the required temperature conditions wlthin the interior 6 of the lehr. Control or variation of the temperature conditions in the lehr during its operation is efl'ected by the provision of a plurality of dampers or controllable inlets 8, whereby cold air from the outer atmosphere may be admitted to the flue to dilute the hot gases passing therethrough when, for example, the increase in the heat transference is not required or when less heat is required, as'for instance when annealing a greater weight of ware per unit of time. The dampers or controllable inlets 8 may be similar to those used for the admission of coolin air in lehrs of the kindhereinbefore referre to and shown in the Mulholland patents and they are arranged at positions along or adjacent to the inclined plates 3 and 7 at the bottom of the flue.

Alternatively, the lehr may be constructed with a flue which is of constant or uniform cross sectional area and which is provided with an adjustable plate or elongated damper 9 which may normally lie parallel to or flush with the bottom of the flue (Fig. 4) The plate 9 is adapted to be adjusted by means of a hand wheel control 10 or similar device, whereby its inner end at a: may be moved towards the upper plate 5 of the flue so that it assumes an inclined position similar to that of the plate 3 in Fig. 1 and thus provides a gradually reduced or restricted passage for the hot gases when it is desired to increase the heat transference for raising the temperature in the interior 6 of the lehr. A further plate 11 is provided which is adapted to be moved together with the plate 9 so that the cross sectional area of the flue, beyond the restricted portion, may gradually assume its normal or full cross section.

While we have shown the invention applied only to the heating portion of the lower iue 2, it is obvious that the same or similar mechanism could equally well be used in connection with the right hand or cooling end 12 of the flue 2 (Fig. 1) which is used as a cooling flue and in which controllable amounts of air are inducted through the dampered passage 13 and drawn off through the inclined passage 14 to the header 15 and thence through passages on either side of the lehr tunnel to the upper wind box 16 from which they are drawn by any suitable means such as an exhaust fan. We have shown a. longitudinal upper cooling flue 17 extending from the exit end of the lehr and open at said end, as at 18, and provided with a plurality of dampered openings 19 communicating with a take-off conduit 20, which in turn communicates with the wind box 16. Thus it will be seen that suitable means are provided for cooling a material portion of the lehr tunnel, this means being controllable in its effeet by a suitable adjustment of the dampers in passages 19. The flue 17 may be constricted by means such as are shown in Figs. 1 and 4 and this construction is contemplated by us.

The elongated members or dampers 9 and 11 may also be made as a long flexible strip adjustable at intervals along its length by any suitable means, such as are shown at 10, for varying the cross section of the flue progressively from one point to another as may be desired.

While we have shown and described but two specific embodiments of our invention, many modifications may be made therein without departing from the spirit thereof, as set forth in the appended claims, which are to be construed as broadly as the state of the prior art permits.

We claim:

1. A lehr for annealing glassware comprising a tunnel, a flue associated with said tunnel,"and means for passing a temperature controlling medium through said flue, said flue being of varying cross sectional area and having the surface area through which heat is transferred between the glassware and said temperature controlling medium in said flue uniform throughout the lengthof said flue.

2. A lehr for annealing glassware comprising atunnel, a flue associated with said tunnel, means for passing a temperature controlling medium through said flue, and means for Varying the cross sectional area of said flue along a portion 'of its length including an inclined plate constituting a portion of one wall of said flue.

3. A lehr for annealing glassware compris ing a tunnel, a flue associated with said tunnel, means for passing a temperature controlling medium through said flue, and adjustable means for varying the cross sectional area of a portion of said flue.

4. A lehr for annealing glassware comprising a tunnel, a flue associated with said tunnelymeans for passing a temperature controlling medium through said flue, and means. for adjustably varying the cross sectional area of a portion of said flue mcluding an elongate inclined damper positioned within said flue. v

5. A lehr for annealing glassware comprising a tunnel, a flue associated with said tun.- nel, means for passing a temperature controlling medium through said flue, and means for adjustably varying the cross sectional area of a portion of said flue including an elongate damper disposed within said flue and parallel with the outer wall thereof when 1n position to give said flue 1ts greatest eifective cross/sectional area. I

6. A lehr for annealing glassware comprising a tunnel, a longitudinally extending flue having a common wall with said tunnel, means for passing atemfperature controlling medium th ough said ue, and means for ing a tunnel, a longitudinally extending flue having a common wall with said tunnel, means for passing a temperature controlling medium through said flue, and means for varying the cross sectional area in a predetermined'portion of said flue while maintaining constant the wall area thereof in heat transfer relation with the glassware in said tunnel.

- 8. A lehr for annealing glassware comprising a tunnel, a longitudinally extending flue having a common wall with said tunnel, means for passing a temperature controlling medium through said flue, and means for adjustably varying the cross sectional area of'a portion of said flue including an elongate inclined damper positioned within said flue and constituting a part of the wall thereof opposite said common wall.

9. A lehr for annealing glassware comprising a tunnel, a longitudinally extending flue having a common wall with said tunnel, means for passing a temperature controlling medium through said flue, and means for varying the temperature gradient Within said tunnel including a progressively constricted portion in said flue, the common wall of said flue being of uniform width throughout the length of said flue, whereby to vary the velocity of the medium within said flue and consequently the rate of heat transfer between said medium and the walls of said flue.

10. A lehr for annealing glassware comrising a tunnel, a longitudinally extending 'ue having a common wall with said tunnel, means for passing a temperature controlling medium through said flue, and means for varying the temperature gradient'within said tunnel including a progressively constricted portion in said flue, said constricted portion being interposed between unconstricted portions along said flue.

Signed at London, England, this 11th day i of June 1928.

THOMAS WARDLEY. HAROLD V. E. RENN.

varying the cross sectional area in a predetermined portion intermediate the ends of said flue.

85W 7. A lehr for annealing glassware compris-

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