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Tropic-Aire Inc. v. Auto Radiator Mfg. Co.

April 1, 1938


Appeal from the District Court of the United States for the Northern District of Illinois, Eastern Division; Philip L. Sullivan, Judge.

Author: Sparks

Before SPARKS and MAJOR, Circuit Judges, and LINDLEY, District Judge.

SPARKS, Circuit Judge.

Appellant charged appellee with infringement of its United States patents to Waters, No. 1,684,900, and to Butterfield, No. 1,834,141. The former was issued September 18, 1928, on an application filed November 20, 1926; the latter was issued December 1, 1931, on an application filed February 20, 1929. The defense was invalidity and non-infringement. At the conclusion of the evidence the court dismissed the bill of complaint for want of equity. Claim 5 of the first patent and claims 1 and 5 of the latter patent were involved. The court concluded that each claim, if valid, was so limited in scope, in view of the prior art, as not to be infringed by appellee; and conversely, if the claims were construed broadly enough to be infringed by appellee, then each claim invalid in view of the prior art.

The Waters patent covers a hot water heating system for automobiles, in which a small percentage of the water from the engine cooling system is passed through the car heater in such a way as to efficiently heat the car, yet not interfere with the cooling system of the engine. Efficient heating is said to be provided by the interior design of the heater, by means of the volume and velocity of the water through the heater, and also by its exterior general design.The lack of interference with the cooling system is said to be obtained by restricting the percentage of the flow from the cooling system through the car heater, and not through the cooling radiator. That restriction is accomplished by designing the inlet and outlet connections of small size, and also by the method of connecting them to the cooling system. Waters stated that there must not be a diversion of water from the cooling system greater than 20 per cent; that that amount or less will effectively heat the car if the water be made to circulate rapidly and in the form of a thin sheet.For this purpose he designed his heater with large radiating surfaces in proportion to the volume of water space, which he says will function properly if its volumetric capacity is as low as one pint of water, and where the connections are of such size that the conduits for an automobile with two such heaters have an approximate capacity of one quart. He specifies the size and proportion of other elements of the system with great particularity, for instance, that the couplings by which the heater hose are connected to the cooling system should be of three-eighths inch pipe, or less. He suggests the use of a thermostatically operated valve for the purpose of confining the circulation of the cooling water to the engine jacket and the heater until the water has reached a predetermined temperature, whereupon the valve will open to permit the water to flow to the cooling system. However, it is then necessary that the diversion from the cooling system of the hot water for heating purposes shall not be so great as to impair its function of cooling the engine cylinders, and herein lies the point of controversy between the parties, appellant claiming that its patented system, when the valve is open in any degree, will at all times prevent more than 20 per cent of the water from being diverted from the cooling system through the heater.

Waters, in his drawings and specifications, discloses a number of slightly different arrangements of the elements of his claim, but for the purposes of this case he relies on Fig. 13.


The engine 1 is provided with the usual water jacket which communicates through the usual radiator hose 2 with the usual cooling radiator 3. The water passing through 3, goes by way of pipe 4 to a pump 5, where it is re-introduced into the engine jacket. In the radiator hose connection 2 there is provided a fitting 66, having an outlet 67 which is connected with hose 22, leading to the heat radiator 25. After passing through 25 the water is returned to the cooling system through hose 26, which is connected to pipe 4 on the suction side of the pump 5. A thermostatically operated valve 44" is located between the engine jacket and the diverter coupling 66. In its argument and brief appellant suggests that this valve may be located between 66 and the cooling radiator 3, as exhibited in Figs. 10 and 11. However, these figures disclose other forms of construction of appellant's system, and it is not stated in the specifications that the location of the thermostatic valve, as shown in Fig. 13, may be changed except in the constructions shown in Figs. 10 and 11.

In Fig. 13, the control valve 44" is constructed so that it can not completely shut off the flow through conduit 2. This is provided for in the usual type of thermostatic valve used in automobile circulating systems by drilling a three-sixteenths inch hole through the valve disc, or by the use of a valve that will not completely close by the area of a three-sixteenths inch hole. Claim 5, the only one in issue, is in the margin.*fn1

The condition of the art was disclosed by prior United States patents 1,124,403 to Faruolo, and 1,581,761 to Muir; and French patents 384,583 to Bayractarow, and 587,872 to Nanteuil. It is admitted that each of these patents discloses a hot water heating system connected to the cooling system of an automobile.

Faruolo discloses a water cooled engine which sends hot water through a conduit, consisting of a metal pipe section and a flexible or hose section to the top portion of the cooling radiator. The water returns to the engine by way of a pipe connecting near the base of the cooling radiator, a pump adjacent thereto, and a return pipe or manifold. The heater supply tube or pipe extends downward from the hose section bending laterally and extending underneath the floor of the car to the heater positioned in front of the rear seat and practically flush with the floor. A valve is placed in the vertical portion of the heater supply pipe, which is manually controlled, and it is worthy of note that the claim in suit is not restricted to a thermostatic control. A restriction is used in the hose section which deflects some of the water through the valve when open, to the heater. When the valve is wide open, substantial amounts of water may be forced to the heater by the restriction in the hose section; if, however, the valve is closed, then no water flows to the heater. The water deflected to the heater retunrs through a pipe extending from the heater to a pipe where it mingles with the water returning from the cooling radiator. The circuit through the heater is said to be "in parallel" with the cooling circuit passing through the cooling radiator.

The Muir patent discloses a hot water heating system connected to a cooling system. It is a series system in which all the water which goes through the heater returns to the automobile by way of the main cooling radiator. The heater has a plurality of water tubes, as does appellee's. Muir convects the air around the hot water tubes of the heater by means of a fan adjacent the cooling radiator, which blows the air through a pipe to the heater. Appellee likewise uses a fan, except that its fan is in the interior of the car, and instead of the water passing through the heater in a wide sheet or stream, it passes through it in a plurality of parallel channels which mutually interfere with one another, so far as free radiation of heat in all directions is concerned. In other words, in Muir, as in appellee's system, heat is delivered by convection of air currents around the tubes, rather than by free radiation in all directions.

Bayractarow discloses an engine with a water outlet through a pipe to the cooling radiator, and a return to the engine through a pipe. At a valve in the outlet pipe to the cooling radiator is a passage leading to the heater, and there is a return passage from the heater to the cooling radiator. The cock of the valve is provided with two buttons, or with a double manipulating lever whose two ends are connected by pull cords or rods to another double lever fixed to a handle disposed within reach of the driver. When the valve is set for cooling conditions, and the heater is not in use, the circulation is directly through the outlet pipe and valve from the engine to the cooling radiator. When heat is desired the valve is turned so as to direct the hot water through the passage leading to the heater, and in turn through the return passage to the cooling radiator. The valve can be set to any position between its extreme off and on positions by manipulation of the handle near the driver.

Nanteuil discloses an engine jacket with a water connection, or outlet, leading directly to the upper part of the cooling radiator, with a return pipe from the lower part of the cooling radiator to the engine. A valve is shown in the outlet pipe leading from the engine. Between this valve and the engine is connected a pipe which leads hot water from the engine outlet pipe to the heater. There is a return pipe which returns the water from the heater to the return pipe of the cooling radiator, thus completing the heating circuit. No pump is shown ...

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