MR. JUSTICE BRANDEIS delivered the opinion of the Court.
The Permutit Company is the owner of Gans Patent No. 1,195,923, for an apparatus for softening water, applied for August 5, 1911 and granted August 22, 1916. It brought, on February 23, 1928, this suit in the federal court for northern Illinois, against Graver Corporation, to enjoin infringement of Claims 1 and 5. The defendant denied both the validity of the patent and the infringement. The District Court held both claims invalid, 37 F.2d 385. The Circuit Court of Appeals for the Seventh Circuit affirmed that decision; and also held that the
Water is hard because it contains the salts of calcium and magnesium. It may be softened by distillation or by adding to the water certain other chemicals through which the hardening constituents in solution are changed to an insoluble form and precipitated. Such softening may also be effected by the use of zeolite, a hydrated alumino-silicate found in nature. When hard water is passed through zeolites they give up their sodium to the water and take from it the calcium and magnesium as a new base. Zeolites have the peculiar quality that, after becoming exhausted in such use, they may be regenerated by passing a solution of common salt through them, whereupon they give up their new base of calcium and magnesium and take back their sodium base. They retain indefinitely these valuable properties.
The chemical attributes of zeolites, and their effect upon hard water, had been known long before the application for the patent in suit. But zeolites were not employed commercially as a water-softener because, as then found in nature, they were ill adapted for use in filters and the expense of mining them was large. Gans invented a process for producing artificial zeolites and a process of softening water by means of them. The United States patents issued for those inventions had expired before
As described in the specification, the apparatus consists of a cylindrical container within which are "a number of horizontally disposed perforated plates." Near the bottom is one upon which rests a layer of sand (or quartz). This supports a bed of zeolites. At some distance above the zeolites is another perforated bed of sand "through which the water to be softened may be first filtered." There are piping connections so that the hard water may be run into the casing through the zeolite bed and out to the soft-water service line. The chamber is also provided with means for cutting off the hard water and introducing a flow of salt water to regenerate the zeolites; and with means for washing out of the container the contaminated brine and any accumulated dirt. As so constructed, the filter may operate by letting the hard water flow either downward through the upper sand bed to the zeolites or upward to them through the lower sand bed. On March 2, 1920, The Permutit Company disclaimed from the scope of Claim 1 any apparatus "in which the water to be softened is so introduced into the casing that it passes upwardly through said layer of zeolites." It is conceded that Graver Corporation's 1927 type of water softener does not infringe Claim 1 as in it the water passes upward.
First. The apparatus described in the specification closely resembles sand filters long used. The elements enumerated above, alone and in combination, are confessedly old. The only invention seriously urged under Claim 1 is the substitution of a "free" for a "locked" zeolite bed — a matter which is not referred to either in the specification or in the claim. In earlier filters the zeolites had been held in place by locking the bed; that is, by placing a metal screen either immediately over the layer of zeolites or over a layer of burlap or excelsior resting upon them. The occasion for a screen is that zeolite grains are lighter than the sand and gravel on which they rest. In flowing the water or the regenerating solution upward through the zeolite bed in an upflow softener, or in backwashing the zeolites in a downflow softener, for the purpose of cleansing them of accumulated slime and dirt, the lighter grains may be washed out through the flow pipe unless impeded in some way. Gans is alleged to have discovered that a locked zeolite bed is erratic in action and will soon cease to give soft water; that through such a bed the hard water will flow unevenly; that preferred channels of flow will form; that the zeolites contiguous to them will be speedily exhausted and the hard water will pass through unaffected, although the great mass of zeolite material remains unexhausted; and that it is necessary to have an open space above the top of the zeolites in order to furnish opportunity for the zeolites to rise or boil, and to spread out and reform in the bed. The invention relied upon consists in removing the close fitting cover from the zeolite bed and in providing adequate
We have no occasion to consider whether this alleged Gans invention of a "free" zeolite bed rises to the dignity of invention or whether, as Graver Corporation contends,
The question of compliance with the requirement of disclosure laid down by § 4888 was not adverted to in either opinion of the Second Circuit Court of Appeals sustaining the validity of the patent, 279 Fed. 713; 22 F.2d 916
We think that these views rest upon misconception. The absence in the claims of a sand bed placed above the zeolites does not imply that the zeolite bed is to be unconfined. The only normal inference from such silence is either that it was deemed immaterial whether the zeolite bed be locked or free, or that if a free bed is preferable, it was not claimed because it lacked novelty. The drawing annexed to the specification, it is true, shows a layer of sand or quartz at a point above the zeolites and an unoccupied space between it and the top of the zeolite bed. But there is no suggestion on the drawing or elsewhere that the upper plate bearing the layer of sand or quartz has any purpose except to serve as a mechanical filter through which" the water to be softened may be first filtered," or that the unoccupied space has any other purpose than that of similar spaces in sand filters long
Second. The further contention is that Claim 5 can be sustained on the ground that, in providing for "means connected to the lowest point of the casing for removing the salt solution," it introduced a novel element constituting invention. The only novelty suggested is that of placing the means at the lowest point of the casing. It does not require the exercise of the inventive faculty to place at the bottom of a receptacle the outlet through which it is to be drained, Smith v. Springdale Amusement Park, 283 U.S. 121, 123; Carbice Corp. v. American Patents