The opinion of the court was delivered by: CAMPBELL
CAMPBELL, District Judge.
This action is brought to obtain relief by injunction and damages for the alleged infringement of reissue patent No. 16,611, issued to Leo L. Lewis, assignor to Carrier Engineering Corporation, for method of and apparatus for cooling and vehtilating, granted May 3, 1927, on application for reissue filed February 12, 1927, original No. 1,583,060, May 4, 1926, original application filed December 22, 1924, and of patent No. 1,670,656, issued to Walter L. Fleisher, assignor by mesne assignments to Auditorium Ventilating Corporation, for ventilating system, granted May 22, 1928, on an application filed May 20, 1927.
Both of these patents relate to methods and apparatus for conditioning the air in auditoriums, theaters, and similar places in which a considerable number of people assemble.
The plaintiff, Auditorium Conditioning Corporation, a New Jersey corporation, which changed its name from Auditorium Ventilating Corporation, has title to both patents.
The defendant St. George Holding Company, a New York corporation, is the owner, and the defendant St. George Amusement Company, a New York corporation, is the operator, of a theater in the Eastern district of New York, called the St. George Playhouse, which contains an air-conditioning system put into operation subsequent to the issuance of said patents in suit, after notice and prior to the filing of the bill herein, and continuously operated from that time on.
The problem that confronted Lewis and Fleisher, of air conditioning for human comfort, was very different from the so-called air conditioning for industrial purposes, in which the factors of moisture and heat are always known, and the system can easily be operated either to add moisture, add heat, or to remove heat or moisture, according to a predetermined plan. The materials processed constitute the real load; the people in such a plant usually being a negligible factor.
The prior art in the main deals only with industrial systems.
In air conditioning for human comfort within a public inclosure such as a theater or the like, the factors of moisture and heat are not always known, as the people to a preponderant degree constitute the heavy load, and this is an uncertain load which cannot be estimated, due to the constant shifting of audiences.
The people may arrive in large numbers and pack the theater to capacity at some time during the day, while at another time the theater may be almost empty.
This, however, while the dominant, is not the only, difficulty, as changes in weather have some effect on the load, and each person gives off heat and moisture, and also gives off odors which in the aggregate become seriously objectionable. The quantities of heat and moisture given off differ with different people, and the variations in temperature and humidity do not follow the same curves.
The heat and moisture given off by individuals tend to raise the temperature and absolute amount of moisture in an atmosphere, but the relative humidity will actually fall, since the heat given off is proportionately greater than the moisture exuded.
The human organism is extremely sensitive to atmospheric conditions, and, to be considered comfortable, the humidity in the air must not be oppressive, the air motion must create a pleassant effect without excessive evaporation from the skin, and there must also be an absence of streaks and drafts.
In addition, the temperature and moisture must be corelated with the air motion, or the air at comfortable temperature with too much moisture would feel hot and muggy, or the same air with too little moisture would increase evaporation and feel cold, as it would tend to dry the membranes of the nostrils and throat, which would be physically injurious.
Attempts were made to solve the problem prior to the dates of invention of the patents in suit, but in all of them all of the air was treated, and, if any reheating of cold air was accomplished, it was by means of heating devices, susally requiring the use of a steam boiler under summer conditions, which was objectionable.
The patentees of the patents in suit taught the art that all the air need not be treated, and that mechanical reheaters could entirely be eliminated and comfortable conditions produced at a reasonable cost despite the quantities of air handles.
Both of the patents in suit have a primary fourfold object in view:
First, to provide for producing and controlling atmospheric conditions in an inclosure by means of a system wherein only part of the air is conditioned, instead of all of it.
Second, to provide a system where the need for mechanically reheating the dehumidified air is entirely eliminated. Thus, although air is chilled to a low temperature in order to produce desired dehumidification, that air is introduced into the inclosure at a higher and comfortable temperature, yet no mechanical reheaters are employed.
Third, to provide a system wherein the same volume of air may at all times be introduced, even though the constituent proportions of dehumidified air and other air are varied, so that equable conditions may be maintained throughout the theater and fluctuations in temperature be limited to a degree or two.
Fourth, to enable such systems to be installed and operated at a reasonable cost.
Large quantities of air are used by both of the patentees of the patents in suit in achieving these objects.
This is also true of the St. George Playhouse of the defendants, in which about 33,000 cubic feet of air per minute is used, and was true of the adjudicated Rochester system, in which about 108,000 cubic feet per minute were used.
An appreciable part of the air so used in both inclosures was recirculated air, or air which is reused without conditioning.
Recirculated air is in practice often called "bypassed" air, due to the fact that it bypasses the conditioner instead of passing through it, and mixes at the outlet end of the conditioner with conditioned air discharged from the conditioner.
This bypassing seems to me to be the gist of both of the patents in suit.
Lewis states that his invention relates to air conditioning of rooms where people congregate, such as theaters; that it is desirable to maintain a relative humidity preferably not greater than 50 per cent.; that it is essential to keep the air circulating in order quickly to absorb heat and moisture from the bodies and the exhalations of the people; and that he avoids first cooling the air to dehumidify it and then heating it up again by mechanical means, which would require the operation of a boiler in summer, by a new arrangement which contemplates bypassing. He states his primary object is to provide a cooling system "in which the bulk of the air is recirculated without being conditioned."
Only a small part of the air is taken from outside and conditioned; this small part being mixed with the recirculated or bypassed air, "thus saving in refrigeration and eliminating the necessity of means for reheating the air during the summer months."
The working of the Lewis system is shown in Exhibit 8, in which outside air under control of damper A, comprising less than one-third of the air handled by the system, is cooled in the conditioner to a point where its excess undesirable moisture is squeezed out, and leaves the conditioner saturated at a low temperature, too cold for comfort. If it entered the theater in this condition without reheating, the occupants would be exposed to dangerously cold air. However, in emerging from the conditioner, the cold conditioned air meets a large volume of air returning from the theater.
This air, which in practice comprises about two-thirds or more of the air handled by the system, is the recirculated or bypassed air under the control of damper C, which is used for reheating the cold conditioned air. The cold conditioned air and the bypassed air then mix in the mixing chamber before being discharged by the fan into the theater. Some air from the theater is released to the outer atmosphere under control of damper B. The fan operates at constant speed, and not only draws outside air into the conditioner through damper A, and air from the theater through damper C, but discharges the mixed air from the mixing chamber into the theater.
Since it operates at constant speed, it always delivers the same amount of air into the theater, so that circulation requirements of thirty cubic feet par seat may always be maintained. The constituent parts of conditioned air and bypassed air may be varied, so that, when the theater temperature seeks to rise, more cold air from the conditioner and less bypassed air will be mixed for delivery to the theater, but, if the condition in the theater calls for greater reheating, less air will be taken through the conditioner and more will be bypassed from the thereater.
The bypassed air is higher in temperature than the cold conditioned air due to the people in the theater who are giving off heat, to infiltration of heat through walls, etc., and to heat given off by lights, motors, and other apparatus.
The bypassed air is lower in relative humidity than the cold, dehumidified air, which is saturated or at a 100 per cent. relative humidity, because relatively a human being gives off more heat than moisture, so that, although the amount of moisture in a theater, all things being equal, would continually tend to add up, yet, relatively, the percentage of humidity compared to saturation tends to diminish, due to the heat given off by the people, and that added because of hot outdoor climate, from the lights, etc.
Lewis perceived that, due to this phenomenon, air in a theater was a perfect reheating agency, which could be mixed with the conditioned air for raising its temperature and lowering its relative humidity, and therefore conditions but a small percentage of the total air, and recirculates or bypasses a large volume, which reheats the conditioned air and eliminates the necessity for steam rehaters under summer conditions.
Lewis has a dew point control which may be set at any desired point, and fixed the temperature of the spray of water in the conditioner. The outside air entering the conditioner will thus be reduced in temperature by the cold sprays to a point depending upon the setting of the control. A hygrostat D responds to relative humidity which is a function of temperature, and controls operation of dampers A, B, and C. This hygrostat is in the return duct leading from the theater to the mixing chamber, and, since the movement of air is very rapid, it responds almost immediately to changes in condition within the theater.
Thus, as theater conditions vary, the hygrostat will cause the dampers to operate so that more or less air is conditioned and bypassed.
If more conditioned air is required, the hygrostat will cause damper A to open more widely and bypass damper C to close somewhat; whereas, if the theater tends to become a bit too cool, the reverse action will take place. The bypass damper, in any event, will never close, so that the conditioned air will always be augmented in volume and reheated by a sufficient volume of bypassed air.
Lewis shows a positive relief duct, but in practice relief may take place either through an exhaust or through any desired opening in the theater.
While the system is designed for all year round, and winter conditioning equipment is provided, the winter heating arrangement forms no part of the bypassing system for summer operation primarily covered by the invention.
Fleisher went further than Lewis, in that he taught that, while some outdoor air should be taken in at all times, the total quantity of cooled and conditioned air desired for mixing with recirculated air could with advantage be composed of a portion of outside air and a portion of washed and cooled air from the room, thus saving the large difference in cost arising from the difference in condition between the inside and outside air.
He provided for intaking that minimum of outdoor air required for physiological reasons, and the prevention of odors, and supplied an additional quantity as was required ...