US1654817A - Process of manufacturing glass - Google Patents

Description

Jan. 3, 1928. 1,654,817

A. KADOW PROCESS OF MANUFACTURING GLASS Filed Nov. 16. 1925 2 Sheets-Sheet l /H 00000109000000 \'-1 azzsz gm INVEN'T'UR AUGUST KAoow. (OW W. b

aHorneYS Patented Jan. 3, i928.

UNITED STATES PATENT. OFFICE.

AUGUST KADOW, OF TOLEDO, OHIO, ASSIGNOR TO THE IIBBEY GLASS MANUFACTUR- ING- COMPANY, A CORPORATION OF OHIO.

- PROCESS O1 MANUFACTURING GLASS.

Application filed November 16, 1923. Serial No. 875,052.

My invention relates to the manufacture of glassware, and has for its object the mprovement of the were and the simplificat1on and speeding up of the process of manufacture.

Features of my invention are capable of general use, but the invention is particularly applicable to the production of hollow ware that is blown with a moil which differs in thickness from the walls of the finished articles. I will describe my invention as applied to the manufacture of blown tumblers, and particularly as combined with the process described and claimed in the copendin joint application of applicant and Alvah Parker, Serial No. 704,57 1, filed April 7, 1924.

The process of manufacturing tumblers now in generalv use is to first anneal the tumblers with the moil thereon, an operation which consumes several hours. After annealing, the obviously defective articles are thrown out and the moil is cracked off of the apparently good articles.- This is usually done by making a scratch on the desired line of severance and then applying heat to that line, producing strains that result in cracking the glass, usually along the desired line, but sometimes along undesired lines.

The edge ct the tumbler is left rough by the cracking oft process, and is smoothed by grinding during which there is considerable loss from breakage. Grinding leaves the tumbler wet and dirty, and it is cleaned and dried before the next operation. The ground edge has sharp corners and is unglazed. To round the corners and glaze the edge, a glazing or fire finishing flame is played upon the edge of the tumbler. As the edge of the tumbler must be melted while the body of the tumbler is left comparatively cold, strains are set up which remain in the finished article permanently, or until breakage results. The only way to relieve such strains would be by re-annealing after fire finishing.

The attached moil is'usually of more irregular thickness than the body of the article. Because of this, cooling the article with the moil thereon sets up strains, unless this cooling 1s done very slowly and carefully. The annealing process is greatly lengthened because of the slow heating and cooling required to avoid breakage, the extra strains introduced by the presence of the departing widely from the intended line of severance.

My improved process is as follows, reference being had to the accompanying drawings, in which Fig. 1 1s a diagrammatic view illustrating the complete process and Figs. 2 audit are diagrammatic views of onestep in the'process.

A glass batch is gradually charged into a meltlng tank'A. As the batch is melted, the molten glass flows into a refining chamber B. and from the refinin chamber to a working chamber C. I pre er to has the glass in the refining chamber cooler t an proper working temperature, and heat the chamber C so that the temperature of the glass is gradually raised as it flows into the working chamber and passes to the working point.

It is easier to maintain the glass at the wort:-

ing point substantially uniform in temperature and consistency when the refined glass is heated to a bi her temperature while it passes to the wor ing point than it is when the refined glass ,cools as it approaches the working hoint.

Uniformity of temperature and consistcncy of the glass at the working point results in :fewer strains within the formed articles, facilitating subsequent operation and producing better ware.

The glass is worked out of the tank G, and blown, as at D, preferably by an automatic gathering and blowing device.

The articles are dropped from the blow ing machine onto a carrier E, from which (lit lift

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they are taken and placed in an apparatus F, where the moil is burned off. I prefer to pass the articles from the molds to the burning off apparatus with as little cooling as possible. The burning ofi' apparatus may be constructed in any suitable manner.

The burning off process consists in the application of a sharp thin flame along the desired line of severance to melt a ring'of glass, and the pulling off of the moil by its own weight or otherwise. After severance is completed, I prefer to continue the melting flame for a time a short distance from the severed edge, to melt ofl anv stringing glass and smooth up the edge, but this finishing action may be produced by any other suitable application of heat.

Some of the glass which is melted to effect the severance remains on the severed edge, and surface tension gives this glass the form of a bead along the severed edge. The shape of the bead may be modified and con trolled as more fully described in the above identified copending application.

Figs. 2 and 3 illustrate diagrammatically the bead forming step. In Fig. 2 there is shown a tumbler 10, supported in a chuck 11 carried by a shaft 12 rotated by a friction wheel 13 contacting the face of a driving friction wheel 14. The wheel 13 may be slidably keyed onto the shaft 12, and moved by handle 15 radially of driving wheel 14 to regulate the speed of rotation of the chuck.

An annular burner 16 is'provided for melting off the moil17. Thechuck may be rotated with such speed that the molten glass on the severed edge is moved outward by centrifugal force to form an outwardly extending bead, as shown at 18 in Fig. 2. The chuck may be rotated comparatively slowly by moving wheel 13 nearer the center of wheel 14, as shown in Fig. 3, and the flame may be so regulated that the article 19, shown in that figure, will have an inwardly projecting bead 20. Preferably, an intermediate speed is chosen, and the bead is placed symmetrically on the severed edge.

There is a tendency for glass of substantially equal thickness throughout to heat and cool more rapidly at the exposed edges. A thickened bead along the edge tends to make the temperature changes of the edge more nearly equal to those of the adjacent sides, and this is an advantage in annealing, as it makes possible more rapid changes in the temperature of the articlewithout causing detrimental temperature-differences between the edge and the adjacent glass.

Where a hot glass article is placed in burning ofl' apparatus, the chuck or other member contacting the article must be of non-conducting material, or else heated, in order to avoid breakage or strain in the article. Preferably, the article is not only prevented from cooling durin the burning off process, but the chuck holding the article is heated, and that, with the rising heat from the burning off and fire finishing flame, heats the article nearly to annealing temperature, or about as hot as it can be handled without danger of deformation. Where necessary, additional heat may be applied to exposed portions of the article during the burnin off and finishing processes. In Figs. 2 and 3 a burner 21 is shown for heating the chuck and article therein. In this way there is the least possible strain introduced by differential temperature between the burned off edge and the body of the article.

The articles are taken from the burning off apparatus and placed in an annealing leer G. The leer may be of any suitable type, but I prefer to use a muffle tunnel leer. I prefer to use a temperature higher than that usually employed in the entrance end of the leer so that the articles are heated to a high annealing temperature within a short time.

Annealing is for the purpose of allowing re-arrangement of molecules to relieve strains caused by a varying consistency of glass and differential temperatures or rates of cooling. This re-arrangement takes place scarcely at all below what is termed the critical temperature, which approaches that at which the glass may be permanently deformed under pressure; and the rate of the re-arrangement increases rapidly as the temperature is raised above this point. I prefer to heat the glass as hot as possible without having it suffer change of shape, in order to shorten the annealing period. I can apply sufficientheat to quickly raise the temperature of the glass to a high annealing point because the articles enter the leer at nearly annealing temperatures, so that the application of heat will not crack them even where the walls are not of uniform thickness, as where the bottoms of tumblers are thicker than their sides, for example.

The-necessary duration of annealing is, of course, proportional to the strains which are introduced into the Ware, and so the uniform character of the glass at the gathering point tends to reduce the time necessary for annealing. Likewise, the absence of cooling between blowing and annealing avoids the introduction of cooling strains, and so eliminates the necessity for long annealing to remove such strains. The speed With which the temperature of the article may be safely changed, both in heating and cooling, is much greater with an article having walls of comparatively uniform thickness than it would be with an article having a moil of uneventhickness attached thereto. After the glass is cooled down below the critical point, further cooling may be very rapid,

be set up by ture at which the articles are introduced into the leer and the comparatively uniform thickness of walls resulting from the removal of the moil, the high temperature at which the annealing is done, and the speed with which the articles are cooled after passing below annealing temperature. As a result of these combined features, I have passed tumblers through the leer in less than eight minutes with very satisfactory results.

It is possible, and under some circumstances even preferable, to heat the articles sufliciently during the burning off process so that no further removal of strains is necessary, and the articles may be transferred at once to heated or noneconducting receptaelse, or other means may be used to prevent too rapid cooling until they are below the critical temperature.

The articles are taken from the leer and inspected on a carrier H and packed, as at I, one of the important features of my invention being that the articles leave the leer in finished form and no subsequent strain in troducing processes are necessary. As will be seen, I substitute a burning off step for cracking ofi, grinding, washing and fire finishing, and greatly shorten the time of annealing, lessening the original cost of. the plant and eliminating most of the workmen required. At the same time the article, which may be packed within twelve minutes of its removal from the blow mold, does not have internal strains introduced by processes subsequent to annealing, and has a beaded edge, if desired.

While I have described niy process as applied to blown tumblers, it is obvious that other articles could be made by a similar process; and while all of the described steps co-operate in producing the desired resultin the manufacture ofblown tumblers and similar ware, it is obvious that less than the complete process could be applied with beneficial results. For example, the described method of obtaining uniform glass at the working point is useful in makin quick annealing possible with ware where there is no removal of moil or severance of the article between shapingand annealing. Furthermore, dividing by burning off before annealing is especially useful where a moi is removed from a blown article and where the burning off step is utilized to heat the article to proper'temperature to enter the annealing zone; but it is useful in producing a properly finished annealed edge on the completed article, however the glass is initially shaped and however the annealing after dividing is done.

Other variations, within the scope of the appended claims may be made in the described fprocess without departing from the spirit 0 the invention.

It will be understood that, in the appended claims, where the terms final form and finished shape are used, it is intended to distinguish from such an article as an electric light bulb as it leaves the glass factor before the filament and base have been inserted and the final form has been given. My process, and particularly the annealing step, is pertinent where the ware is thick enough so that the severed edge may be permanently exposed during the useful life of the article.

lVhat I claim is:

1. In the manufacture of glassware, the process which consists in forming a set shape of molten glass, seve ing the set glass by melting it along the line of severance so quickly that severance results and leaves the glass constituting the severed edge of the finished article in substantially its original position with regard to the portion of said. article to which it is attached, and thereafter raising the temperature of the glass for annealing purposes, and finally allowing it to cool.

2. In the manufacture of glassware, the

process Which consists in blowing a glass article, removing the moil by melting the glass along the line of severance so quickly that severance results and leaves the glass constituting the severed edge of the finished article in substantially its original position with regard to the portion of the article to which it is attached, and thereafter anneal ing the article.

3. In the manufacture of a glass article having an edge which is exposed during the normal use of the article. the process which consists in forming a set shape for molten glass, severing the set glass by melting it along a desired line to form said exposed edge of the finished article, and thereafter annealing the article.

4. In the manufacture of a blown glass article having an edge which is exposed during the normal use of the article, the process which consists in blowing the article with a moil attached. severing the moil from the ar-- ticle by melting the lass along the desired line of severance to orm the exposed edge of he finished article, and thereafter annealing the article.

5. In the manufacture of a blown glass article having an edge which is exposed during the'normal use of the article, the process which consists in blowing an article with a moil attached, removing the moil by melting the glass along the line where said edge is to be formed, the melting being performed 1 position with re ard to the so quickly that severance results and leaves the lass constituting the severed edge of the finis ed article in substantially its ori 'nal ortion o the said article to which it is attac ed, and thereafter annealing the article.

6. The process of manufacturing blown open-mouthed glass article, which consists in blowing such an article with a moil attached, melting oil the moil to give the article final form, and thereafter passing the article through an annealing leer, bringing the entire article to a high annealing temperature within a period of not more than ten minutes after it enters the leer and cooling it so that it may be removed from the leer within a period not more than one-half hour after it enters the leer.

7. In the manufacture of glassware, the

rocess which consists in melting a batch to orm molten glass, refining the glass at a comparatively low temperature, reheating the refined glass, shaping the reheated glass to give it the desired form of the finished article, and annealing without allowing it to become cool after shaping, and completing the annealing within one-half hour after shaping.

8. In the manufacture of glassware, the process which consists in dividing a glass article by applying heat intense enough to.

melt the glass along a desired line of severance and leave a severed edge along said line, and heat treating the article so that all portions of it will be at approximately the critical temperature upon the completion of severance.

9. In the manufacture of glassware, the process which consists in dividing glass by applying heat intense enough to melt the glass along a desired line and leave a severed edge along said line, fire finishing the severed edge, and heat treating the article so that all portions of it will be at approximately the critical temperature upon the completion of fire finishing.

10. In the manufacture of glassware the process which consists in forming a set shape from molten glass, directly thereafter melting the shape along a desired line of severance by means of a flame so intense that it severs the glass and leaves a severed edge along the line of its application and thereby gives the final form to the article, forming a bead along the severed edge at the time of severance, and heat treating the article so that all portions of it will be at approximately the critical temperature when severance is completed.

11. In the manufacture of a glass article having an edge which is exposed during the normal use of the article, the process which consists in forming a set shape from molten glass, severing said shape by melting the glass along the desired line of severance so quickly that severance results and leaves the glass constituting the severed edge in its original position with regard to the portion of said article to which it is attached, except for a small amount of glass which is melted and forms a bead along said severed edge, said severed edge forming the exposed edge of the finished article, and thereafter raising the temperature of the glass and annealing the article.

12. In the manufacture of glassware, the process which consists in blowing an article, melting oil the moil along a line by means of a flame so intense that it severs the glass and leaves a severed edge along the line of its application and thereby gives the article its finished form, forming a bead along the severed edge during the severing process, and heat treating the article so that all portions of it will be at approximately the critical temperature when severance is completed.

13. In the manufacture of a blown glass article having an edge which is exposed during the normal use of the article, the process which consists in blowing an article with a moil thereon, severing the moil from the article by melting the glass along the desired line of severance so quickly that severance results and leaves the glass constituting the severed edge of the finished article in its original position with regard to the portion of the said article to which it is attached, except for a small amount of glass whch is melted and forms a bead along said severed edge, heat treating the article so that all portions of it will be at approximately the critical temperature when severance is completed, and thereafter retaining the heat for annealing purposes.

14. In the manufacture of glassware, the process which consists in blowing an article, removing the moil by melting the glass along a line 0 severance by means of a flame so intense that it severs the glass and leaves a severed edge along the line of its application and thereby gives the finished form to the article, fire finishing the severed edge, forming a bead along the edge during severance and fire finishing, and heat treatin the article so that all portions of it will be at approximately the critical temperature when fire finishing is completed.

15. In the manufacture of glassware, the process which consists in blowin an article, removing the moil by melting t e lass along a line of severance by means of a ame so intense that it severs the glass and leaves a severed edge alongthe line of its application and thereby gives the finished form to the article, finishing the severed edge, forming a bead along the edge during severance and fire finishing, and heat treating the articleso that all portions of it will be at approximately the critical temperature when fire finishing is completed, and thereafter retaining theheat for annealing purposes.

16. In the manufacture of a blown glass article havin an edge exposed during the normal use 0% the article, the process which consists in blowing an article with moil attached, removing the moil by melting the lass along the desired line of severance. re-finishing the severed edge and forming

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