Gas Machinery Co. v. United Gas Improvement Co.

• Decision Date: 07 December 1915
• Docket Number: 2642.
• Citation: 228 F. 684
• Parties: GAS MACHINERY CO. v. UNITED GAS IMPROVEMENT CO.
• Court: U.S. Court of Appeals — Sixth Circuit

228 F. 684

GAS MACHINERY CO. v. UNITED GAS IMPROVEMENT CO.

No. 2642.

United States Court of Appeals, Sixth Circuit.

December 7, 1915

Appeal from the District Court of the United States for the Eastern Division of the Northern District of Ohio; William L. Day Judge.

Suit in equity by the United Gas Improvement Company against the Gas Machinery Company. Decree for complainant, and defendant appeals. Reversed.

For opinion below, see 211 F. 672, . . . C.C.A. . . . .

In an infringement suit brought by the United Gas Improvement Company against the Gas Machinery Company, based upon patent No. 857,760, issued June 25, 1907, to Rusby, and patent No 940,925 issued to Dickey, November 23, 1909, both for 'improvements in water gas apparatus,' the court below found for complainant upon the Rusby patent, entering the usual decree for injunction and accounting, but upon the Dickey patent found for the defendant and dismissed the bill. The defendant below appeals, and thus the only questions involved concern the Rusby patent. Its single claim is as follows: 'Means for definitely controlling the quantity and quality of the production of gas, which means comprise the gas generating apparatus and its regulatable air supply connections and an ajutage interposed in said connections and provided with a pressure gauge, whereby the attendant is enabled to introduce a definite volume of air during the interval of each blow, regardless of fire and other conditions in the apparatus, substantially as described.'

The process of making water gas employs, in series, a generator a carburetor, and a superheater, which constitute a 'water gas set.' The generator is an ordinary furnace which carries on a grate a body of burning coal. All the products of combustion pass from the generator into the carburetor. This is a chamber partly filled with checker brick designed to absorb and retain heat. The carburetor opens into another similar chamber, the superheater, also provided with checker brick; and from the superheater one outlet may be opened to the stack or another toward the reservoir for the finished gas. In operation, an air blast is driven by a blower through a flow pipe discharging into the generator under the grate. This air is driven through the bed of hot fuel, and emerges therefrom and passes into the carburetor largely in the form of a combustible gas, called producer gas. In the carburetor, this is ignited and burned, and, as it passes on through the checker brick in the carburetor and superheater, these are raised to high temperatures before what remains of the gases escapes to the opened stack. This process of storing up heat in the second two chambers is continued for an arbitrary time, say three minutes, and is called the 'blow.' The operator then shuts off the incoming air by closing a valve in the flow pipe, and he opens a valve in a steam pipe which also leads to the generator below the grate. The steam passes up through the bed of fuel and is decomposed, and the resulting water gas, which will burn with a blue flame and give heat, but not much light, passes into the carburetor. Here it meets a spray coming from an oil pipe, the valve in which has likewise been opened by the operator. The vaporized oil spray is diffused throughout the gas in the carburetor, and by absorption of the contained heat in the carburetor and superheater in its further progress the gas becomes hot enough, so that the oil content is fixed beyond the danger of precipitation. The gas then has illuminating power, and passes off toward the reservoir through a valve provided and opened for that purpose. This, the direct gas-making step of the process, is continued for a predetermined period, say five minutes, and is called the 'run.' Then the steam and oil are shut off and the air turned on, and so blow and run follow in continuous alternation. From time to time coal is added to the fuel bed to maintain its sufficiency.

The ajutage of the claim is a device interpreting the rate of motion of the entering air blast along the flow pipe. It consists of two very small tubes inserted in the blast pipe and terminating at different points therein, where the air pressure upon the small tubes will, for one reason or another, be different. The pressure conditions induced in the small tubes are then translated by a differential pressure gauge, which displays to the eye the difference of pressure at the two selected interior spots. From this known difference in pressure, in connection with other data, an expert can compute the rate of the flow of the air; and, of course, when the rate of the flow is considered in connection with the time period, the total quantity of flow during the period will be known. At the time of Rusby's invention, this ajutage, with its accompanying differential pressure gauge, was old and company known as a means for indicating the rate of flow and the quantity of flow of air or other liquid passing through a pipe. It had been so used upon water pipes, upon air pipes leading into an air exhauster, upon gas pipes from a gas main to a gas engine, and upon gas pipes leading from a gas holder to a gas-burning furnace, but had never been used upon an air pipe leading to a water gas set.

In order that the operator might be informed regarding the condition of the air supply during the blow, it has been customary to provide a water gauge, which indicated the air pressure below the generator grate. As the propelling force of the blast is supposed to be constant, it would seem to follow that an increase in the pressure below the grate would indicate the passage of an additional quantity of air; but this would be strictly true only so long as the obstructing or retarding conditions in the fuel bed remained the same. If the obstructions increased, as by a cinder bed or an ash bank, there would be a back pressure, and the pressure gauge at this point might show an increase, even though a decreased quantity of air was getting through the fire. It results that the indication furnished to the operator by this pressure gauge would be approximate, but not accurate. Ordinarily, when he saw the pressure falling, he would open the valve to admit more air, or, if the pressure gauge rose, he would know that a smaller opening of the valve was sufficient; but, as the fuel bed becomes obstructed, to maintain the same amount of air passing through the pressure under the grate must be increased enough to compensate for the obstruction, and after allowing for the back pressure increase. Operators had been instructed accordingly, and, for example, had been told to keep the pressure at 18 inches during the earlier part of the day, but in the later part of the day to run it up as high as 21 inches. The defendant was constructing and installing water gas sets operating in this way before the Rusby patent.

E. L. Thurston, of Cleveland, Ohio, for appellant.

A. B. Stoughton, of Philadelphia, Pa., for appellee.

Before WARRINGTON, KNAPPEN, and DENISON, Circuit Judges.

DENISON Circuit Judge (after stating the facts as above).

Whether it was invention to take the ajutage from a pipe leading to an exhauster, which is one kind of an air pump, and put it on a pipe leading from a blower, which is another kind of an air pump, or to take it from a pipe carrying gas from a gas holder and put it on a pipe carrying an element of the gas on its way into the gas holder, is, to say the least, a question of doubt; but this case may be more clearly, as we think, disposed of on another ground. We conclude that the relation of Rusby's ajutage and gauge to the 'set' is the relation between the items of an aggregate, and not the relation between the elements of a combination. This conclusion depends on the general proposition that a metering device, the only office of which is to measure the raw material entering a machine so that the operator may stop when he has put in enough, does not so coact with the machine itself as to be properly characterized as being in combination therewith.

The authoritative cases are few which have considered the distinction between aggregations and combinations, except as it is complicated and confused by the effort to find the line between invention and mechanical skill. See Walker on Patents (4th Ed.) Sec. 32, and cases cited. The rule of aggregation is stated-- probably as sell as possible-- in Macomber's Fixed Law of Patents (2d Ed.) p. 6 (with reference to sections 42-51, q. v.):

'The distinction between an aggregation and a true combination is not always clear. The main test lies in an examination of the result-- the function performed. If that result is the sum of the several actions of the elements, it is an aggregation; if it is the product of those actions-- if the action of one element so modifies the action of another that the resultant action differs from the sum of the separate actions-- it is a true combination.'

We must first disclaim doubting that there would be a combination if the changes in the ajutage or its pressure gauge directly actuated the regulating valve-- as, for example, on the principle of the household thermostat. There would then be a direct inter-relation, just as there is between the air regulating valve and the parts of the apparatus further along whose variable action depends on the amount of air passing through. Likewise, it must be remembered that the existing ajutage was not modified or adapted in any degree or applied in any physically new way, to make it fit this situation. There is no claim of novelty in this respect.

We disclaim, also, the idea that there can be no true combination in any case where the action of either the operator or material operated upon is necessary to cause one element to modify the action of...