Waterproof Insulation Corp. v. Insulating Con. Corp.

• Decision Date: 18 July 1957
• Docket Number: Civ. No. 9225.
• Citation: 153 F. Supp. 626,114 USPQ 265
• Parties: WATERPROOF INSULATION CORP. v. INSULATING CONCRETE CORP. and Zonolite Company.
• Court: U.S. District Court — District of Maryland

153 F. Supp. 626

114 USPQ 265

WATERPROOF INSULATION CORP. v. INSULATING CONCRETE CORP. and Zonolite Company.

Civ. No. 9225.

United States District Court D. Maryland.

July 18, 1957.

Harry Goldman, Jr., Baltimore, Md., for plaintiff.

Read A. McCaffrey and C. Gordon Haines, Baltimore, Md., Watson, Cole, Grindle & Watson, and Robert F. Conrad, Washington, D. C., for defendants.

R. DORSEY WATKINS, District Judge.

Plaintiff, a Maryland corporation, has sued for declaratory judgment that underground insulated pipe systems installed with its insulating concrete (such a concrete being hereinafter referred to as Wicor) do not infringe defendant Zonolite Company's United States Patent No. 2,355,966 to Goff. Defendant Zonolite Company, a Montana corporation, assignee of the Goff patent, and Insulating Concrete Corporation, a Virginia corporation, and exclusive licensee of Zonolite in the areas in question, counterclaimed for a judgment that such systems do infringe the patent. The validity of the patent is not in issue.¹

The issue of infringement was tried with respect to an underground insulated pipe system installed, with plaintiff's participation, at Richmond, Virginia. The defendants concede that the other Wicor systems within the territory allocated to Insulating Concrete Corporation are not infringements of the Goff patent if the Richmond system is not.

The Goff patent was issued in 1944 on application filed in the Patent Office in 1942. It relates to an underground insulated pipe system composed in part of concrete. Such system is used to convey heated fluid, such as steam or hot water, from a boiler plant to buildings which are to be heated thereby, and is often referred to as a District Heating System. Claim 1, which is the only claim as to which infringement is asserted by defendants, reads as follows:

"1. In an underground heat-insulated pipe-system including a base and heat-insulated, fluid-conductive, expandible and contractible pipe-means supported by said base and having expansion-and-contraction compensation-means at intervals along the length of the system, the novel combination of improvements of said base being of structural-concrete and said heat-insulation of said pipe-means being heat-insulating concrete completely and solidly enclosing and supporting said pipe-means solely on said concrete-base and constituting a monolithic embedment for said pipe-means from each said compensation-means to the next, said insulating-concrete weighing less than 50 pounds per cubic-foot, said pipe-system being capable of conveying fluid with a heat-differential of at least 150° degrees F. without injury to the system."

Although the question of patent validity is not in suit, for a proper understanding of the contentions of the respective parties it is necessary briefly to refer to the use of underground insulated pipe systems prior to the invention disclosed in the Goff patent. Prior patents and publications had taught the use of cellular concrete insulation in such systems. Cellular or cell-concrete is a light weight concrete which may be made by mixing soap suds with water and cement. The resulting dead air entrapped in cells provides a high insulating quality but the material is weak, easily crumbles, and is incapable of supporting by itself the weight and movements of large pipes. Because of the structural weakness of cell-concrete, underground pipe systems prior to the Goff invention utilized heavy rollers spaced along the pipe as a permanent support for the pipes insulated by the cell-concrete. Such prior systems also utilized a structurally strong encasement of reinforced concrete, brick, or tile to protect the cell-concrete from damage by external forces.

It is also clear that the heat insulating properties of vermiculite, the principal aggregate specified by the Goff patent, were well known prior to the Goff invention. It had been used as an ingredient of heat insulating concrete for floors, walls, acoustical plasters and the like. However, the prior art did not teach that such heat insulating concretes, either cell-concrete or vermiculite, could be used underground to sustain the entire support of heavy steam mains, or that such heat insulating concretes required no structural encasement when so used.

Accordingly, the prior art underground insulated pipe systems required four characteristic elements—namely, a supporting base; conventional supports for the pipe, usually pipe rollers or rockers; heat insulation for the pipe; and structural encasement to protect the insulation and thus the pipe. The Goff invention calls for only two basic elements in combination, namely, a structural concrete base and a heat insulating concrete solidly enclosing and supporting the pipes solely on the base and constituting a monolithic embedment for the pipes. 149 F.Supp. at pages 954-55.

Plaintiff's Richmond system comprises a structural concrete base, with Wicor heat insulating concrete poured monolithically around the metal pipe. It employs conventional metal pieces to which the pipe is welded midway between expansion joints; it has occasional metal guides, but primarily the pipe is initially held off the ground and prevented from sagging by the use of insulating bricks or blocks of Wicor around which the concrete is subsequently poured and forms a firm union.

Both Wicor and concrete using the vermiculite aggregate have satisfactory insulation factors and compressive strength.

The aggregate in Wicor is shredded rubber. The insulating concrete used in the Wicor installations weighs 61 pounds per cubic foot.

Plaintiff contends that there is no infringement by it in that (a) Wicor weighs 61 pounds per cubic foot and the critical language of claim 1 of the Goff patent calls for "insulating concrete weighing less than 50 pounds per cubic foot"; and, (b) in the Wicor installations the pipe is not supported solely by the insulating concrete but is supported in part by the welded anchors and occasional metal guides, but primarily by insulating blocks of Wicor.

I. The 50 pound per cubic foot limitation in the Goff patent.

It is entirely clear that Wicor is not a literal infringement of the Goff patent since the Wicor insulation weighs 61 pounds per cubic foot and the patent Claim 1 calls for insulating concrete weighing less than 50 pounds per cubic foot. In substance, defendants say that the 50 pound per cubic foot limitation is only a convenient way of expressing an insulating value, and that at the time of the patent application, this was the common method of expressing such value. There is no contradiction of defendants' testimony that the 50 pound weight limitation in Claim 1 relates to insulating value of the insulating concrete, and that density was at the time of the patent application the universal and simplest way of referring to insulation value. The evidence further establishes that at the time of filing the patent application, aggregates used in foam or cell-concrete were silicates, and that such concretes with a weight of 50 pounds per cubic foot had a K-factor² of approximately 1.4, which was good heat insulating concrete.

This is emphasized by the fact that the 50 pound limitation in the Goff patent was admittedly not inserted by amendment in order to avoid the prior art. Accordingly, there is no problem of file wrapper estoppel. Hunt Tool Co. v. Lawrence, 5 Cir., 1957, 242 F.2d 347; New York Scaffolding Co. v. Whitney, 8 Cir., 1915, 224 F. 452, 462, certiorari denied, 1915, 239 U.S. 640, 36 S.Ct. 161, 60 L.Ed. 482. The Board of Appeals of the Patent Office construed this limitation as a designation of satisfactory heat-insulating concrete, distinguishing it in this respect from the prior art which did not disclose "good heat insulating concrete", and from "conventional concrete, which is not fairly heat insulating."

Since patentee's invention was for an underground system,³ and was not directed to insulating concrete per se,⁴ there was no need to restrict the patent to, or specify, a particular weight, except to designate a satisfactory level of insulating value, in terms and manner then customarily used and well understood.

It is true that Goff could have used a K-factor expression in Claim 1, rather than weight, to designate insulation values. However, Goff was stating a minimum satisfactory insulating value, since his preferred embodiment⁵ of the invention as described in the specifications is an insulating concrete of 23-pounds per cubic foot, which has a K-factor of about 0.6; and it is conceded that in general, heat insulating value increases with a decrease in density.

Moreover, weight alone, as distinguished from weight as a measure or symbol for insulating value, has never been urged by plaintiff as a consideration of significance prior to this litigation. In the Wicor literature, and negotiations for the Richmond job, plaintiff stressed compressive strength and the insulation value, without mention of weight.

Since plaintiff's Richmond system has a stipulated K-factor of 1.23 at 61 pounds per cubic foot, which is lower than the K-factor of 1.4 for defendants' insulating concrete at 50 pounds per cubic foot, and since plaintiff's product embodies the inventive features of the Goff patent of a structural concrete base, and a cement that insulates, supports and protects the pipe, the court holds that plaintiff's installation appropriates the substance of the Goff invention. Hartford Empire Co. v. Swindell Bros., 4 Cir., 1938, 96 F.2d 227, 231; Frick Co. v. Lindsay, 4 Cir., 1928, 27 F.2d 59, 63; Wine Ry. Appliance Co. v. Baltimore & Ohio R. R., 4 Cir., 1935, 78 F.2d 312, 316. This would be true even if plaintiff's device followed the patent imperfectly, or if it did not function as well as the patented structure, so long as the substance of the invention is appropriated. Matthews v. Allen, 4 Cir., 1950,182 F.2d 824, 827-828.

Defendants claim that as plaintiff's Richmond installation...