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November 20, 1997

UNDERSEA BREATHING SYSTEMS, INC., Plaintiff, Counter-Defendant,
NITROX TECHNOLOGIES, INC., Defendant, Counter-Plaintiff.

The opinion of the court was delivered by: DENLOW

 This patent case arises out of the issuance of a patent for an oxygen enriched air generation system designed principally for use by dive shops for filling scuba tanks. The Court conducted a bench trial from October 6-10, 1997, involving six in-court witnesses, two who testified by deposition, and numerous exhibits. The case involves two primary issues: 1) Was Plaintiff's patent infringed by Defendant? The answer is no. 2) Is Plaintiff's patent valid? The answer is yes. The following constitute the Court's findings of facts and conclusions of law pursuant to Rule 52(a) of the Federal Rules of Civil Procedure. To the extent certain findings may be deemed conclusions of law, they shall also be considered conclusions. Similarly, to the extent matters contained in the conclusions of law may be deemed findings of fact, they shall also be considered findings. See Miller v. Fenton, 474 U.S. 104, 113-14, 106 S. Ct. 445, 451-52, 88 L. Ed. 2d 405 (1985).


 1. Plaintiff, Undersea Breathing Systems, Inc. ("Plaintiff") manufactures and markets oxygen-enriched air ("nitrox") generation systems for the production of divers' breathing gas. Its corporate officers are William H. Delp, II ("Delp"), Richard Rutkowski ("Rutkowski") and Dr. J. Morgan Wells ("Wells").

 2. Defendant, Nitrox Technologies, Inc. ("Defendant" or "NTI") also manufactures and markets nitrox generation systems for producing divers' breathing gas. Its corporate officers are Cynthia Olson and Robert Olson ("Olson").


 3. This Court has jurisdiction over the parties and over the subject matter of this action pursuant to 28 U.S.C. §§ 1331 and 1338(a).

 4. Venue is proper in this district pursuant to 28 U.S.C. §§ 1391(c) and 1400(b).


 5. United States Patent Number 5,611,845 ("the '845 patent") was issued on March 18, 1997, to Delp, as the inventor. (Px 1). Delp subsequently assigned the patent to Plaintiff. Delp filed the patent application for the system which led to the '845 patent on August 22, 1995. (Px 2).

 6. The patent describes a particular type of nitrox generation system using a permeable membrane gas separation system for separating compressed air into a nitrogen gas component and a nitrox component. (Px 1).

 7. The patent contains 33 claims. Claims 1 and 23 are independent claims with the remainder being dependent.

 8. Plaintiff alleges that Defendant infringed independent claim 23 and dependent claims 24 and 29 of the '845 patent. Defendant denies the allegation and asserts that the '845 patent is invalid.

 9. Claim 23 claims:

A system for generating [nitrox] comprising:
an air supply for supplying compressed air;
a permeable membrane gas separation system for separating a nitrogen gas component and [a nitrox] component from said compressed air;
means for detecting an oxygen concentration in said [nitrox] component;
means for selectively heating and cooling said compressed air as it passes between said air supply and said permeable membrane gas separation system; and (emphasis added)
means for selectively distributing said [nitrox] component for further use.

 ('845 patent, col. 9-10).

 10. The principal issue with respect to Plaintiff's complaint for infringement is whether Defendant's system contains a means for selectively heating and cooling compressed air. The Court finds that Defendant's system does not contain a means for selectively heating and cooling the compressed air. In particular, the Court finds that Defendant's system lacks an equivalent structure for selectively cooling the compressed air. The Court's analysis of this issue is contained in the Conclusions of Law at Section VII.

 11. Dependent claim 24 describes:

A system as defined in claim 23, and further comprising a compressed [nitrox] storage assembly,
a compressor,
a compressor feed line supplying said [nitrox] component to a compressor inlet and
an outlet line interconnecting a compressor outlet to said compressed [nitrox] storage assembly.

 ('845 patent, col. 10, lines 6-11).

 12. Dependent claim 29 states:

A system as defined in claim 24, wherein said means for detecting the oxygen concentration is interconnected with an outlet of said permeable membrane gas separation system to permit monitoring of the oxygen concentration of said oxygen enriched air component passing through said outlet.

 ('845 patent, col. 10, lines 35-41).


 A. The Parties' Involvement in Diving and Patent Development.

 13. Delp attended college and took general engineering courses but did not receive a degree. He has had a continuing interest in diving since 1962, when he was certified as a diver. Delp has been involved in commercial diving and producing life support breathing gas mixtures for the diving industry since 1985. He is certified as a hyperbaric technician. Delp recognized that a system for generating nitrox using permeable membrane technology, which eliminates the need for a separate pure oxygen source, offered substantial advantages, such as increased safety and decreased cost and effort in producing nitrox.

 14. Robert Olson has a bachelor's degree in oceanography. He has been a recreational diver since 1974. Olson has previously developed and patented systems using the nitrogen stream produced by permeable membranes for applications in the transportation industry, such as inerting containers used to ship grain and produce. (Dx 10 and 11). Olson assigned his patents to his then-employer, Prolong Systems, Inc., which produced and sold nitrogen generation systems for inerting purposes. In 1994, Olson began to work on a device to create nitrox for dive shops. He installed his first nitrox generating unit in July 1996. The NTI system takes filtered, compressed air through a bundle of hollow fibers that separates the oxygen from the nitrogen using selective permeation. (Dx 25).

 B. Diving.

 15. When a diver's body is submerged under water, the liquid exerts pressure against the body in every direction. At sea level, the diver is subjected to normal atmospheric pressure, which can be quantified as 1 Atmosphere. The amount of pressure increases linearly as the diver submerges deeper below the water surface. For example, diving to a depth of 33 feet below sea level increases the pressure by 1 Atmosphere. Any diver, at any depth, must be in pressure balance with the forces at that depth. The body can only function normally when the pressure differences between the inside of the diver's body and forces acting outside is very small. (Px 29).

 16. As pressure increases with depth, the diver's circulatory system is also compressed. If a diver surfaces too quickly, the rapid decompression can cause arterial gas embolisms, bubbles in the blood stream, to form. (Px. 47, p. 49-50, PP 9-14, U00437-38.) The bubbles of air in the blood vessels block some of the small terminal vessels, cutting off the blood supply to nerve endings. Known as decompression sickness or more popularly as the bends (and euphemistically by divers as "bubble trouble"), the consequent blockage throughout the circulatory system, can cause severe pain, temporary paralysis, permanent damage, or death.

 C. Gases in Diving.

 17. Divers's breathing gas is composed of eight gases, which are normally found in varying quantities in the atmosphere. These gases are oxygen, nitrogen, helium, hydrogen, neon, carbon dioxide, carbon monoxide and water vapor. Oxygen is the most important. Normal ambient air contains approximately 21 percent oxygen, 78 percent nitrogen, and 1 percent trace gases. It is the oxygen that is actually used by the body. The other 79 percent of air serves to dilute and carry the oxygen. Pure (i.e., 100 percent) oxygen is often used for breathing in hospitals and in aircraft. However, a diver who breathes pure oxygen under pressure may experience oxygen poisoning. (Px 29). Because it imposes a significant decompression obligation, ambient air is not the "ideal" breathing mixture for diving. Decompression obligation refers to the necessity when surfacing from a dive to stop periodically and allow the diver's body to adjust to the new pressure exerted on the body to avoid the bends. Decompression obligation is dependent on the quantity of nitrogen absorbed by the body during the course of a dive. Both the rate of nitrogen absorption and the total amount of nitrogen which can be taken in by the body are determined by the nitrogen partial pressure in the breathing gas. (Px. 2, Tab 47, p. 21). Although nitrox is any combination of nitrogen-oxygen, nitrox mixtures with greater than 21 percent oxygen can offer significant advantages to many types of diving. (Px 2, Tab 47, p. 21). For the purposes of this opinion, any reference to nitrox will indicate a nitrogen-oxygen mixture which contains more than 21 percent oxygen.

 18. If both the toxic and decompression obligation reducing properties of oxygen are considered, an "ideal" diving gas mixture for any depth / time combination can be produced. Such a mixture would offer the maximum decompression advantage without the risk of oxygen toxicity. The advantages of such a mixture as compared to air are that it will either increase the allowable time on a successive dive or reduce the surface interval, the time a diver must spend at surface level between dives, or both. (Dx. 36, p.31-32.)

 D. Pressure and Compression.

 19. A gas mixture that is safe to breathe at the surface may not be acceptable at depths experienced by divers. The breathing gas will not flow out of its storage tank unless it is at a higher pressure than its surroundings. Because pressure increases as the diver's depth increases, the breathing gas in the diver's tank must be stored at a pressure higher than the maximum that the diver will encounter. Other components of air, such as carbon dioxide or hydrocarbon contaminants, may be tolerable at ambient pressure but dangerous at the higher pressures encountered at depth.

 20. Generating and compressing nitrox for diving implicates several problems. The enhanced oxygen content increases the risk of explosion or fire, necessitating the use of special cleaning and safety procedures. Moreover, because diving time, decompression time, and surface intervals vary with the gas composition of the breathing gas used, the oxygen and other gas components must be precisely controlled.

 E. Prior Nitrox Generation Systems.

 21. Prior to the '845 patent, nitrox was produced in one of three ways. The first, partial pressure blending, requires the mixture of compressed pure oxygen and compressed air or pure nitrogen. The second, the continuous blending method used by the National Oceanic and Atmospheric Administration ("NOAA"), involves the mixing of compressed pure oxygen with air at ambient pressure and the compression of the resulting nitrox for use in diving tanks. Both the partial pressure and NOAA continuous blending methods require a separate pure oxygen source and use of the precautions attendant to the use of pure oxygen. The third, the pressure swing adsorption ("PSA") method, uses a molecular sieve that selectively adsorbs nitrogen molecules during pressurization and depressurization with air. (Dx 30, p.12). PSA technology requires cleaning and safety procedures identical to using pure oxygen. (Dx 30, p.12).

 22. During the early 1990s, researchers Rutkowski, a hyperbaric medicine specialist, and Wells, director of the NOAA Experimental Diving Unit, began experimenting with the possibility of using permeable membrane technology as a commercially viable means of producing a safe nitrox breathing gas for divers. The advantage of this technology is the elimination of a pure oxygen source requirement. Rutkowski and Wells tested membrane packages manufactured by Permea and Medal to determine whether the nitrox permeate could be safely breathed at depth and whether contaminants and trace gases might be concentrated in the permeate; they experimented with flow rates to determine the optimum pressure for the feed air.

 F. Permeable Gas Membranes.

 23. The system claimed by the "845 patent discloses a gas separator in the form of a hollow-fiber permeable membrane in combination with additional elements to produce nitrox. See e.g., United States Patent 4,230,463 for a multicomponent membrane for gas separations. (Dx 9).

 25. Each gas has a particular permeation rate; oxygen permeates faster than nitrogen. Thus, when a compressed air stream is fed to the inside of the hollow membrane fiber, the air separates into two streams: a permeate *fn1" stream, at atmospheric pressure, which is oxygen enriched and a nonpermeate stream, near the original, elevated pressure, which is nitrogen enriched (actually oxygen depleted). (Dx 25, 03812-13).

 26. Permeable membranes have been used for gas separation since the 1970s, and hollow-fiber permeable membranes have been used since the 1980s. Their predominant use, however, is the production of nitrogen. (See Px 24 describing AVIR Gas Separation Cartridge).

 27. The use of nitrogen is sometimes referred to as "inerting," that is, displacing the oxygen in an environment with nitrogen. The three points of the "fire triangle" -- fuel, heat and oxygen -- must all be present for combustion to occur. When enough oxygen is displaced by nitrogen, combustion can no longer occur. Also with no oxygen in the atmosphere, most living things can not survive.

 28. Nitrogen is used in the shipping and warehousing industries to prevent combustion, preserve freshness and increase shelf life of produce, or exterminate insects through oxygen deprivation. Other uses for nitrogen include: purging lines and vessels in industrial processes, producing pressurized gas for enhanced oil recovery, pressure testing pipe systems, preventing dust explosions in silos and bins, and supplying inert atmospheres for heat treating. (Dx. 18, pp. 4-5, N00734-35).

 29. In the overwhelming majority of membrane applications, the oxygen-rich permeate is considered a waste gas and discarded. In those few applications in which the permeate is used, such as the generation of nitrox for medical purposes, the permeate is used at ambient pressure. The potential use of permeable membranes to produce oxygen-enriched breathing gas for divers was first being discussed in the 1990's by those engaged in the design and manufacture of equipment for the diving industry. In 1993, Wells and Linda Moroz wrote an article regarding the application of gas separation technology in the preparation of divers' breathing gases. (Dx 6).

 G. The Invention Claimed by the '845 Patent.

 30. The '845 patent claims and discloses a system which is capable of generating an oxygen-enriched, safe breathing gas for use by underwater divers. Nitrox may contain from 22 to 40 percent oxygen. Divers generally use a nitrox mixture containing 32 or 36 percent oxygen (known as Nitrox I and Nitrox II, respectively).

 31. Nitrox has been used as a breathing gas by military, scientific and commercial divers for decades, and began to gain acceptance in recreational diving in the 1980s. Nitrox provides several advantages, such as reduced danger of decompression problems, increased bottom time, and decreased surface interval (the time that a diver must spend on the surface between dives).

 32. In 1993 and 1994, Delp obtained permeable membranes from A/G Technology Corp. and Medal to evaluate the oxygen-rich permeate produced by separation and to determine whether the permeate would be safe and breathable for a diver at a depth where it would be supplied at elevated pressure. Delp focused on the concentrations of oxygen, nitrogen, argon, carbon monoxide, carbon dioxide, hydrocarbons and water vapors; these substances, while safe to breathe at the surface, can be toxic at elevated pressure.

 34. Delp testified that the invention claimed in the '845 patent was conceived and reduced to practice in early 1994 but offered no corroborating evidence.

 35. Delp filed an application for a patent on his invention on August 22, 1995.

 36. Plaintiff displayed its system at the Dive Equipment Marketing Association ("DEMA") trade shows in January 1996 and January 1997.

 37. Delp was advised by the patent office in January 1997 that his claims had been allowed.

 38. The '845 patent issued on March 18, 1997.

 H. The NTI System.

 39. Defendant manufactures a nitrox generation system which competes with the Plaintiff's system. (Px 6 and 7). The NTI system has been in existence since at least June of 1996. The NTI system takes filtered compressed air through hollow fiber membranes to produce a nitrox permeate stream. An oxygen analyzer confirms the percentage of oxygen in the stream as it is fed into the intake of a standard high pressure compressor. A flow control allows an operator to adjust the nitrox mixture up to 40 percent oxygen. (Px 6).

 40. The NTI system is manufactured in the United States.


 41. The market for nitrox generation systems such as those sold by Plaintiff and Defendant consists primarily of dive shops located in the United States. Of these, only approximately 1,500 dive shops have the financial resources to purchase a system.

 42. Plaintiff has the manufacturing and marketing capability to exploit the market.

 43. The lifespan of an enriched air generation system is indefinite and depends on the life of the membrane. Therefore there is no replacement market for these systems.

 44. The systems manufactured and sold by Plaintiff range in price from $ 6,900 for the smallest unit to $ 50,000 for the largest.

 45. The systems manufactured and sold by Defendant range in price from $ 9,000 for the smallest system to $ 24,000 for the largest system.

 46. Since the '845 patent issued, Defendant has sold at least three systems that were manufactured in the United States.


 47. Olson and Christian St. Claire, NTI's vice president of sales, displayed a bare membrane at St. Claire's booth at the DEMA show in January 1996 to ascertain whether there would be a market for a commercial product using membrane technology. Olson and St. Clair saw Plaintiff's system at that time. Delp advised Olson that he had applied for a patent on his system, and that he intended to enforce the patent upon its issuance. He threatened to sue Olson if Olson attempted to sell his device. For the remainder of the DEMA show, Olson and St. Claire displayed Plaintiff's logo and referred all inquiries regarding the membrane to the Plaintiff's booth.

 48. In early September 1996, Delp learned of the installation of the NTI system at a dive shop and advised Olson that NTIs system would infringe the '845 patent when it issued.

 49. In January 1997, Delp informed Olson and St. Claire that the claims of the '845 patent application had been allowed. Olson obtained a copy of the '845 patent on the day it issued and immediately faxed it to membrane manufacturers. Olson continued manufacturing and marketing the NTI system.

 50. On March 24, 1997, Plaintiff filed suit against NTI alleging direct and contributory infringement of the '845 patent. NTI filed counterclaims for a declaratory judgment of non-infringement, a declaratory judgment of invalidity and unenforceability under 35 U.S.C. §§ 102 and 103, and a declaratory judgment of patent misuse, as well as a counterclaim seeking a statutory penalty provided for by 35 U.S.C. § 292.

 51. After suit was filed, Defendant obtained a written opinion from counsel that its system did not infringe Plaintiff's patent. (Dx 47).



 52. Plaintiff claims direct or, alternatively, contributory infringement. Persons who make, use or sell the patented invention are direct infringers. Herbert F. Schwartz, Patent Law & Practice (2nd ed. 1996) (hereafter "Schwartz"), p. 77. Contributory infringers are persons who aid and abet direct infringers without themselves making, using, offering to sell, or selling the patented invention. Id. The patentee carries the burden of proving infringement by a preponderance of the evidence. Rohm and Haas Co. v. Brotech Corp., 127 F.3d 1089, 1997 WL 643917, at *3 (Fed. Cir. 1997).

 53. A person infringes a patent when she "without authority makes, uses, offers to sell, or sells any patented invention, within the United States or imports into the United States any patented invention during the term of the patent . . . ." 35 U.S.C. § 271(a). A court's first step in an infringement analysis is to properly construe the claims. Markman v. Westview Instruments, Inc., 52 F.3d 967, 976 (Fed. Cir. 1995), aff'd, 517 U.S. 370, 134 L. Ed. 2d 577, 116 S. Ct. 1384 (1996). This is a question of law. Markman v. Westview Instruments, Inc., 517 U.S. 370, 116 S. Ct. 1384, 1389-96, 134 L. Ed. 2d 577 (1996). After the claims have been properly construed, they are then compared to the accused system. Markman, 52 F.3d at 976. This is a question of fact. Kegel Co., Inc. v. AMF Bowling, Inc., 127 F.3d 1420, 1997 WL 574561, at *4 (Fed. Cir. 1997).

 54. Plaintiff alleges that Defendant's system infringes independent claim 23 and dependent claims 24 and 29 of the '845 patent. A dependent claim is infringed only if the independent claim on which it rests is infringed. Wolverine World Wide, Inc. v. Nike, Inc., 38 F.3d 1192, 1199 (Fed. Cir. 1994).

 A. Claim Construction.

 55. In determining the proper construction of a claim, the court has numerous sources that it may properly utilize for guidance. These include both intrinsic evidence (e.g., the patent claims, specification, and prosecution history) and extrinsic evidence (e.g., expert testimony). Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed. Cir. 1996). In most situations, an analysis of the intrinsic evidence alone will resolve any ambiguity in a disputed term. Id. at 1583. Unless the specification or the file history indicates that the inventor intended another meaning, a claim term will be accorded its "ordinary and accustomed meaning." Wolverine World Wide, Inc., 38 F.3d at 1196. "Ultimately, the court must construe the claim language according to the standard of what those words would have meant to one skilled in the art as of the application date." Wiener v. NEC Electronics, Inc., 102 F.3d 534, 539 (Fed. Cir. 1996).

 56. Under the doctrine of claim differentiation, claims should be presumed to cover different inventions; therefore, the court should avoid an interpretation of a claim that would make one claim read like another. Laitram Corp. v. Rexnord, Inc., 939 F.2d 1533, 1538 (Fed. Cir. 1991).

 B. Construction of Means Plus Function Language.

  57. Claim 23 contains means-plus-function language. If construed literally, a means plus function claim element would be construed to cover every conceivable structure that could perform the recited function. This broad construction of means plus function elements has been restricted by 35 U.S.C. § 112, P 6 which allows a patentee to claim an element of his invention in means-plus-function language but also "provide[s] a standard to make the board claim language more definite." Valmont Industries, Inc. v. Reinke Mfg. Co., Inc., 983 F.2d 1039, 1042 (Fed. Cir. 1993). Section 112, P 6 states:

An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.

  Paragraph six directs a court to construe means-plus-function language by turning to "the specification and interpreting that language in light of the corresponding structure, materials, or acts described therein, and equivalents thereof, to the extent that the specification provides such disclosure." In re Donaldson, 16 F.3d 1189, 1193 (Fed. Cir. 1994).

  58. A claim using means-plus-function language must still " 'particularly point out and distinctly claim' the invention." In re Donaldson, 16 F.3d at 1195 (quoting 35 U.S.C. § 112, P 2). Although the patentee need not recite "structure, material, or acts" in a claim's means-plus-function element, to satisfy the enablement requirement, "the patent specification must describe some structure which performs the specified function." Valmont Industries, Inc., 983 F.2d at 1042. However, "there is and can be no requirement that applicants describe or predict every possible means of accomplishing that function." In re Hayes Microcomputer Products, Inc. Patent Litigation, 982 F.2d 1527, 1535 (Fed. Cir. 1992) (internal quotations omitted).

  59. A limitation containing means-plus-function language is "not rendered openended by the presence of another claim specifically claiming the disclosed structure underlying the means-plus-function clause or an equivalent of that structure." Laitram Corp., 939 F.2d at 1538. The statute expressly provides that the patentee is entitled to a claim covering equivalents as well as the disclosed structure. D.M.I., Inc. v. John Deere & Co., 755 F.2d 1570, 1574 (Fed. Cir. 1985).

  C. Prosecution History of the '845 Patent.

  60. Delp's original patent application contained 24 proposed claims, three independent claims and 21 claims all dependent on what was to become independent claim 1 of the patent. (Px 2A, U00134). In a PTO Examiner's Action on May 28, 1996, the examiner allowed independent claim 1 and rejected for obviousness the two other independent claims, claims 23 and 24 of the original application. (Px 2A, U00196-97).

  61. The original, proposed independent claim 23 attempted to claim:

A process for generating breathable [nitrox] ...

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