H. K. Porter Co. v. Baldwin Locomotive Works

• Decision Date: 09 November 1915
• Docket Number: 1967.
• Citation: 227 F. 216
• Parties: H. K. PORTER CO. v. BALDWIN LOCOMOTIVE WORKS et al.
• Court: U.S. Court of Appeals — Third Circuit

227 F. 216

H. K. PORTER CO. v. BALDWIN LOCOMOTIVE WORKS et al.

No. 1967.

United States Court of Appeals, Third Circuit.

November 9, 1915

Francis T. Chambers, of Philadelphia, Pa., and James I. Kay and Robert D. Totten, both of Pittsburg, Pa., for appellant.

Wm. A Redding and William B. Greeley, both of New York City, for appellees.

Before BUFFINGTON, McPHERSON, and WOOLLEY, Circuit Judges.

WOOLLEY Circuit Judge.

This is an appeal from a decree of the District Court of the United States for the Eastern District of Pennsylvania, dismissing a bill of complaint, which charges the defendants with infringement of Letters Patent No. 953,334, dated March 29 1910, granted the complainant, as assignee of Charles B Hodges, for Method of Operating Compound Compressed-Air Engines. The claims in suit are 1 and 4, which, if valid, are admitted to be infringed. The defense is invalidity. The grounds of defense are five. Lack of patentable invention and anticipation by prior patents are two. These will be considered together; the others will be disposed of in their order.

The patent is for a method, and claim 1 is as follows:

'1. The method of operating compressed-air engines, consisting in carrying the air at high pressure through and expanding it in one cylinder, and thereby reducing it below lowest atmospheric temperature, re-heating the exhaust air from said cylinder when confined by extended exposure to air heating at atmospheric temperature and thereby increasing the volume thereof and its capacity to generate power, and carrying the re-heated air through a low pressure cylinder.'

Claim 4 discloses the same method, but by words which we italicize, indicates another or an additional result. This claim is as follows:

'4. The method of operating compressed-air engines, consisting in carrying the air at high pressure through and expanding it in one cylinder and thereby reducing it below lowest atmospheric temperature and re-heating the exhaust air when confined by extended exposure thereof to air at atmospheric temperature and thereby increasing it to the necessary volume to generate substantially like power within another cylinder of greater cubical contents and carrying such re-heated air through such low pressure cylinder.'

While the drawings in the patent are of compound compressed-air locomotives, and while such engines are especially the object of the inventor, nevertheless the claims are sufficiently broad and the specification sufficiently explicit to embrace a method of operating compound compressed-air engines of any character.

The charge of infringement, however, relates to and is confined to the manufacture by the Baldwin Locomotive Works and use by Four States Coal & Coke Company, of compound compressed-air locomotives of the type which appears in the drawings. The testimony in support of the charge is restricted to the manufacture and use of such locomotives. The controversy is between locomotives. Therefore, we will restrict our consideration, and, should we find the patent valid, we will limit our decision, to the subject-matter of this litigation, which extends only to the validity of the claims of the patent in so far as they relate to the method disclosed for operating compound compressed-air locomotives. In so restricting our consideration and decision, we follow the course of this court in Hagan v. Swindell, 204 F. 442, 122 C.C.A. 628, where a like situation developed.

The patent deals with changes in temperature and the development of power from compressed air. Hodges' invention, if such it be, was a contribution to an art in which compressed air is used as a motive power under certain conditions. Compressed air has long been used as a motive power, but it has not been extensively used in competition with steam and electricity, because of its lower efficiency. Its use, however, is superior to that of electricity or steam in places and under conditions where there is risk of fire. Therefore, compressed-air engines are chiefly used in mines.

Engines in which air and steam are used as power do not greatly differ in type. Each contains a boiler-like receptacle in which is stored the power creating medium and means for its escape into a cylinder, where, by expansion, power is developed and transmitted by pressure to a movable piston. When steam or compressed air is used in an engine with a single cylinder, it but imperfectly performs its work because it is but partially expanded, and the exhaust of the unexpanded portion carries away unused power. To meet this waste, there developed the principle of multiple expansion, that is, expansion of the whole medium in two or more cylinders, which include at least an expansion in one cylinder under high pressure and the expansion of what is left in another and a larger cylinder under low pressure.

While power from both steam and compressed air was obtained by expansion in similarly constructed machines, there was one phenomenon developed in the expansion of compressed air, which is not present in the expansion of steam. When compressed air at atmospheric temperature of 60 degrees F. leaves the tank and enters the first or the high pressure cylinder at a pressure of about 250 pounds, there occurs upon expansion a drop in temperature of about 280 degrees F., which produces the intense cold of minus 220 degrees F. At this temperature, the moisture in the air freezes, the lubricants stiffen, the machine stops, and the residuum of power remaining inert in the air is lost. It was known that by re-heating the compressed air, its power could be regenerated, and by re-expanding the regenerated compressed air in a low pressure cylinder there could be obtained from the second expansion a power about equal to that developed by the first, resulting in a transmission of equal power to the piston in each cylinder. The problem was how to re-heat the partially expanded compressed air and thereby restore activity to its latent power.

Without reviewing the efforts to solve this problem, it is sufficient to say that it appears that until the invention of Hodges, it had not been solved in so far as it related to movable compressed-air engines or locomotives. Hodges claims to have solved the problem by making the discovery that there existed in the open air at any temperature, sufficient heat to restore the temperature of partially expanded compressed air to nearly that of its original temperature, from which another and practically equal amount of power is developed upon a second expansion, without reducing it to the prohibitively low temperature limit. In other words, he employed the common element of air as the medium by which to re-heat the chilled expanded air, and to restore its thermal efficiency. It is admitted that this was the thing accomplished, but it is vigorously denied that in it lies invention. Whether the discovery that air contains sufficient heat to restore warmth to inert compressed air, thereby restoring or rehabilitating its power, constitutes invention, depends upon a study of thermo-dynamics, which though learnedly pursued in the testimony and briefs, cannot be indulged in an opinion.

There is much confusion concerning what was known in the arts in which heat is employed as an agency or force, of precisely what Hodges' invention or discovery consists, and to what art it belongs. Therefore, it is necessary to trace, in the briefest possible way, the forces of nature, the laws of physics and the teachings of science which have been employed in the development of this and allied arts.

When Hodges and others approached the problem of obtaining power from compressed air, there were certain principles of dynamics and physics open to them all. It was known that heat is a force of nature and a source of power; that compression of air produces molecular motion which in turn produces heat; that when compressed air is expanded, heat is released and converted into power, and that by the withdrawal of heat, the air becomes cold. Science imprisoned this known force in cylinders, provided for its liberation by expansion against movable pistons, and thereby gathered from heat the power it was known to contain.

It was known to all that air, when not under pressure, contains heat, and that it contains some heat however low the temperature, and that the cheapest of all gases as a heating medium is air, because it possesses heat without cost and is free to all. It was also common knowledge that a cold body extracts heat from its warmer surrounding medium whatever that may be, and conversely, in this devolution, the warm body is made cold. This is due to the transfer of thermal units from one to the other. It was known as a scientific fact, as before stated, that compressed air becomes cold when its heat units are withdrawn by expansion, and that it loses its thermal efficiency and is no longer a source of power until heat units are restored to it in some way or other, and that when heat is restored, compressed air regains a part of its efficiency, ready to be exerted upon further expansion. Knowing this, science provided compound cylinders, that is, two cylinders, in the first to expand compressed air under high pressure, and then when re-heated, to expand in the second the compressed air under lowered pressure, differentiating the sizes of the cylinders to the volume of expansion intended.

These were things well known in thermo-dynamics, in physics and in science, and constituted forces and laws free to be adopted and developed by every one. The problem in the use of these forces and in the application of these principles, consisted in finding a practicable and economical medium by which compressed air after expansion in the high pressure cylinder might be...