Hartford-Empire Co. v. Swindell Bros.

• Decision Date: 21 April 1938
• Docket Number: No. 4273.,4273.
• Citation: 96 F.2d 227
• Parties: HARTFORD-EMPIRE CO. v. SWINDELL BROS., Inc. (AMSLER-MORTON CO., Intervener).
• Court: U.S. Court of Appeals — Fourth Circuit

96 F.2d 227 (1938)

HARTFORD-EMPIRE CO. v. SWINDELL BROS., Inc. (AMSLER-MORTON CO., Intervener).

No. 4273.

Circuit Court of Appeals, Fourth Circuit.

April 21, 1938.

Sidney F. Parham, of Hartford, Conn., and Edwin F. Samuels, of Baltimore, Md. (William J. Belknap, of Detroit, Mich., and Robson D. Brown and Lloyd G. Bates, both of Hartford, Conn., on the brief), for appellant.

William B. Jaspert, of Pittsburgh, Pa., and Lawrence C. Kingsland, of St. Louis, Mo. (Cook & Markell, of Baltimore, Md., on the brief), for appellees.

Before PARKER, NORTHCOTT, and SOPER, Circuit Judges.

PARKER, Circuit Judge.

This is an appeal in a patent infringement suit involving Mulholland reissue patent, No. 17,263, Ingle patent, No. 1,583,046, and Mulholland patent, No. 1,840,463, all relating to lehrs for the annealing of glassware. The judge below held that, as the patents related to improvements in a crowded art, they should be narrowly construed and that, when so construed, they were not infringed by the lehr of defendants. See Hartford-Empire Co. v. Swindell Bros., D. C., 18 F.Supp. 191.

Annealing is a process of controlled heating and cooling of newly made glassware to eliminate or minimize strains in the ware which would otherwise develop. Many glass articles such as jars and bottles are made by pouring molten glass into iron molds and allowing it to harden. When removed from the molds the articles have an average temperature of from 1,200 to 1,300 degrees Fahrenheit. If they are permitted to cool under ordinary atmospheric conditions, the outside of each article will cool more rapidly than the inside, thus causing a contraction of the outer portion and creating a force which will effect a dimensional change in the inner portion. As the inner portion cools, it in turn will contract and will thus create a stress upon the outer portion which has already cooled and it is not sufficiently plastic to permit a dimensional change. As a result, strains will be set up which will cause the article to break or will render it too weak to be of any value. The problem of annealing is to heat the glassware to such a temperature (approximately 1,000 degrees) as will render it plastic and permit the particles of which it is composed to readjust themselves, and then gradually and uniformly to cool it to ordinary atmospheric temperature.

Annealing under modern manufacturing conditions is accomplished by the use of heated tunnels, 70 feet or more in length, called lehrs, through which the newly formed glassware is passed on conveyors. These lehrs are heated at the entrance end to a temperature of between 1,000 and 1,100 degrees, and this temperature is maintained for about a third of the length of the tunnel. Through the next third, which is the critical stage of the annealing process, the temperature is gradually reduced to a little below 800 degrees. Through the remainder of the distance, the effort is to bring the ware gradually to normal atmospheric temperature. Prior to the development of the lehr of the reissue patent, the best lehrs that the art had been able to develop were large stationary brick structures, about 10 feet in width and 70 or more feet in length, to which it was necessary that the glassware be carried from the forming machines. These lehrs were heated at the receiving end by flues which completely encircled the tunnel, applying heat at the sides and top of the tunnel as well as at the bottom in such a way that it was practically impossible to secure a gradual reduction of the temperature between the hot entrance and the critical annealing stage. Longitudinal currents of air were necessarily set up by such a heating arrangement and these subjected the ware in the critical annealing stage to uneven temperatures which were frequently harmful. Narrow movable lehrs, called "unit" lehrs, formed of metal walls insulated with mineral wool, kieselguhr, or other nonheatconducting material, had been devised on the principle of the fireless cooker, for the purpose of annealing by means of the heat which the ware contained when it entered the lehr; but such lehrs proved of little practical value and did not enter into general use.

The original of the reissue patent in suit was applied for March 31, 1925. It covered both a lehr and a process of annealing glassware; but, as the process claims amount to no more than the process of properly operating the lehr of the patent, we may confine our consideration to it. The lehr embodies devices old in the art, but brought together for the first time in such a way as to produce a resultant which is more than the aggregate of their separate functions, i. e., a lehr in which the longitudinal air currents of the prior art are almost entirely eliminated and are replaced by vertical convection currents within the different annealing zones, resulting in greater uniformity of temperature at any given stage of the annealing process. This result has been accomplished by applying heat to the bottom of the heatless "unit" lehrs of the prior art by means of heating flues which serve as the bottom of the tunnel, with means for gradually decreasing the heat towards the discharge end of the tunnel by admitting air through dampers provided in the sides of the flues. Cooling flues are provided for the top of the tunnel, with the result that, since the bottom is hotter than the top, the currents of air created are vertical rather than horizontal. The gist of the invention is thus described in the specification of the patent:

"In carrying out the foregoing objects, I provide a lehr having a plurality of lower flues extending longitudinally beneath the tunnel and a plurality of upper flues extending longitudinally above the tunnel, all of said flues being provided with damper-controlled openings arranged at spaced intervals throughout their length and communicating with the outside atmosphere.

"Heated gases are passed through the lower flues from the receiving end of the lehr toward the delivery end thereof, and the temperature of the gases, and therefore the temperature of the floor of the tunnel throughout its length, is controlled at will by adjusting the dampers in these flues to dilute the gases with air at selected intervals.

"Cooling air is passed through the upper flues in a direction opposite to that of the flow of the heated gases, and the cooling effect of the air is also regulated to control the temperature of the top of the tunnel throughout its length by adjusting the dampers in these flues to permit more or less of the air to escape to the outside atmosphere at selected intervals.

"By properly adjusting the dampers in both the upper and lower flues, the temperatures at the bottom and at the top of the tunnel may be independently regulated so as to control the circulation of local heat-convection currents in the tunnel thereby rendering it possible to distribute the heat uniformly both vertically and transversely of the tunnel."

The claims of the patent relied on are 1, 2, 7, 8, 44, 45, 46, 48, 49, 50, 51, 52, and 53. Of those relating to the construction of the lehr, as distinguished from process claims, 22 and 52 are typical. They are as follows:

"A lehr for annealing glassware comprising a tunnel, a flue associated with said tunnel, means for causing a heating medium to flow through said flue, the said flue being divided into a plurality of independently controllable heating zones, and means, including spaced dampers, for increasing or decreasing, at will, the temperature in any of the said zones.

"A lehr for annealing glassware comprising a tunnel, a conveyor of low heat mass movable through said tunnel for transporting the ware therethrough, while permitting sensitive control of the transference of heat to and from the ware, a flue associated with said tunnel and adapted to conduct a heated medium therethrough, said flue having a plurality of contiguous controllable temperature controlling zones, means for causing a heated medium to flow through said flue, and means including spaced dampers for independently controlling at will the temperature drop in any of said zones, whereby the temperature of the ware may be accurately controlled by temperature of the medium in the flue, and whereby the ware is made quickly responsive to such control."

It will be noted that the last claim covers a certain type of conveyor, in addition to the heating means used for heating the tunnel, but, as this conveyor is covered by the Ingle patent, No. 1,583,046, we shall defer discussion of that feature of the structure until we take up the Ingle patent.

The result of the invention embodied in plaintiff's structure has been to revolutionize the art of annealing the type of glassware produced by the automatic forming machines. Loss from breakage has been reduced from 5 or 10 per cent. to less than 2 per cent. Annealing time has been reduced from approximately 10 hours to an hour and a half. Fuel costs have been greatly reduced, one witness stating that the improved lehr takes care of three and one-half times as much ware as the old type at probably one-fifth of the fuel consumption. And a considerable saving of labor in transferring the ware from the forming machine to the lehr and in tending the lehr has been effected. In short, so manifest are the advantages of the new lehr of the reissue patent that use of the old brick lehr of the prior art has been almost completely abandoned. It is clear, we think, not only that the reissue patent is valid as to the claims in suit, but also that, whether regarded as a pioneer patent or not, it has effected such an advance in the art that it is entitled to liberal treatment and protection by a liberal application of the doctrine of equivalents. Eibel Process Co. v. Minnesota & Ontario Paper Co., 261 U.S. 45, 63, 43 S.Ct. 322, 67 L.Ed. 523; Oates v. Camp, 4 Cir., 83 F.2d 111, 115; Denominational Envelope Co. v. Duplex Envelope Co., 4 Cir., 80 F.2d 186; Wine Ry....