Full opinion text
MEMORANDUM OPINION THYNGE, United States Magistrate Judge. Plaintiffs Genzyme Corporation, Gen-zyme Surgical Products Corporation, Donald P. Elliot, Lynn Halseth, Nicholas F. D’Antonio, and Nicholas J. D’Antonio (collectively, “Genzyme”) filed this patent infringement suit against defendant Atrium Medical Corporation on November 14, 2000. Genzyme alleges that Atrium’s “Oasis” and “Express” chest drainage devices infringe certain claims of five of its patents that relate to chest drainage devices. The five Genzyme patents-in-suit are U.S. Patent Nos. 4,889,531 (the ’531 patent); 4,544,370 (the ’370 patent); 4,715,856 (the ’856 patent); 4,747, 844 (the ’844 patent); and 4,822,346 (the ’346 patent). At times, in this opinion, the court will refer to the ’531 patent as “the D’Antonio patent” and to the latter four patents collectively as “the Elliot patents.” Presently before the court are the parties’ briefs in support of their positions as to the proper construction of the asserted claims of the patents-in-suit. This memorandum opinion is the court’s decision as to claim construction. The court will begin by briefly reviewing the technology and patents at issue. This background is drawn from the patents-in-suit and from the parties’ presentations during the May 16, 2002 claim construction hearing. 1. Background of the Technology The patents-in-suit relate generally to “chest drainage devices,” devices which are used to remove unwanted fluids, such as blood and air, from a patient’s chest cavity. Such fluids may enter the chest during surgery or as a result of trauma. A chest drainage device, in its simplest form, is a bottle attached to a tube inserted into a patient’s chest cavity for the collection of fluids that are drained from that cavity. A. Overview: The Elliot Patents According to Genzyme, Deknatel, Inc., its predecessor company, introduced the first commercially successful group of chest drainage devices in 1967. These early devices, called Pleur-Evacs, drained fluids and air from a patient’s chest cavity through the use of vacuum suction. In such devices, one tube is connected from the device to the patient, while another tube is connected from the device to a source of suction. Body fluids are then drained through the patient tube and into a collection chamber within the device. An important requirement of any chest drainage device is to prevent the reverse flow of air back into the patient while it is removing air from the chest cavity. It is critical to avoid air flow entering back into the patient, which can be caused when the patient takes a deep breath of air, because reverse air flow can jeopardize the patient’s breathing and create a risk of contamination. The Pleur-Evacs prior art chest drainage devices discussed above used water-based safety features to prevent the reverse flow of fluids through the drainage device. More specifically, for this purpose, the prior art devices employ a “water seal,” a column of water that allows the forward flow of air in one direction towards the source of suction, while preventing the reverse flow of air back into the patent’s chest cavity. There are, however, several drawbacks to these “water seal” based devices. First, in order for the water seal to work effectively, water must be introduced into the device and be maintained at specific levels. Without priming the water levels before and during use, evaporation lowers the water levels within the device and thus changes the pressures at which the “fail safe” features are designed to function. This requires significant set-up time and maintenance. A second limitation is that if the device is moved, jostled, or accidentally knocked over, the resulting water spillage will cause the device to stop working, putting the patient in jeopardy. To solve these problems caused by the use of water as a seal, the Elliot patents disclose a “waterless” (or “dry”) chest drainage device that eliminates the water seals used in traditional chest drainage devices and replaces them with a mechanical “one-way valve.” The one way valve, like the water seal that it replaces, permits vacuum pressure to evacuate air and fluid from the patient, while preventing reverse flow. This allows for accurate pressure regulation and reverse flow protection without the need for maintaining water levels. In addition to this innovation, the Elliot patents also claim additional design improvements, including a number of pressure relief and control valves and a diagnostic air leak indicator. The ’844 and ’346 patents, which are related continuations in part, share the same specification, but have claims of differing scope. According to the specification of the patents, the invention replaces prior art water seals with a fluidless valve mechanism that provides foolproof reverse flow protection. The disclosed apparatus has multiple valves that assist in regulating pressure in the system. The valves include a check valve, a positive pressure relief valve, a control valve, and a negative pressure relief valve. The check valve, when connected to receive air from the exhaust port of the bottle, effectively prevents back flow into the system. The type of check valve shown in the patent figures is a “flapper-type” check valve that opens in response to a relatively low pressure differential. The positive pressure valve is provided to vent any positive pressure above a predetermined value to the atmosphere, in the event that a positive pressure blows out the check valve. Similarly, a negative pressure valve, disclosed as a “popper-type” valve, is provided to respond to high negative pressures in the device by opening to admit air from the atmosphere. A control valve, disclosed as a “screw-type” valve, operates to control the pressure within the air chamber. The apparatus described in the specification also includes a diagnostic indicator, which is depicted in Fig. 1 of the ’844 patent as transparent U-tube 62. Air removed from the patient passes through the U-tube. The U-tube, when filled with fluid, serves as an air leak detector, as well as an indicator of the inhalations and exhalations of the patient. The court has reproduced the portion of Figure 1 thatshows U-tube 62 below. The ’370 and ’856 patents, which ^re also continuations in part that share the same specification, constitute improvements on the invention of the ’844 and ’346 patents. The specifications of these patents include all of the elements of that invention, but also include an intermediate diagnostic tool — U-tube 62a — that holds sterile water to detect leaks and patient breathing characteristics. The inventors, Dr. Elliot and Dr. Halseth, discovered that moving the U-tube to a downstream location provided an improved diagnostic tool that reduced the phenomenon of fluid collecting in the U-tube and backing up the patient tube. Thus, in the normal operation of claimed chest drainage device air and fluids are evacuated from the patient’s chest cavity through a drainage tube. The air passes through the U-tube air leak indicator, which is placed either near the inlet of the device or near the outlet of the device. The air then follows the flow path through the device into the open space above the collection chambers. The air flows through a mechanical one-way valve and exits the device through the air chamber. When the U-tube is filled with fluid, air leaks from the lungs can be observed as air bubbles flowing through the tube. B. Overview: The D’Antonio Patent Another important element of a chest drainage device is its ability to regulate the level of pressure within its system that is applied to the patient. The application of too much suction will harm the patient, while the application of too little suction will not provide the desired drainage of harmful fluids from the cavity. The prior art devices, which employed water-seals to perform the function of a one way valve, also relied upon water-based designs to regulate the level of suction applied to the patient. Specifically, these devices used “water manometer” styled suction controls — water-filled U-shaped tubes — that would allow atmospheric air into the chest drainage device to regulate pressures. By varying the water level, doctors and nurses could vary the level of suction pressure applied to the patient. However, any loss of water, either through evaporation or accidental jostling of the device, placed the patient at risk by the loss of suction control. The D’Antonio patent, which is entitled “Dry Bottle Drainage System,” discloses an improved chest drainage .device in which the water-based suction regulation system is replaced with a mechanical “dry” suction regulator. Instead of employing a water-based control mechanism, the chest drainage device disclosed in the D’Antonio patent utilizes the selective leakage of atmospheric air to regulate the pressure in the suction chamber by controlling a set of mechanical valves. The mechanical regulator can be set at a particular pressure level and will self-adjust to maintain that pressure level. Specifically, the D’Antonio patent specification discloses a wound drainage system that includes an inlet port, a collection chamber, a suction chamber, a suction port, and a suction regulator. The collection chamber collects fluids, both liquid and air, that are withdrawn from a patient. A tube connected to the inlet port connects the collection chamber to the patient. The suction chamber provides a regulated suction to the fluid collection chamber. Whenever the pressure in the collection chamber exceeds that of the suction chamber, air evacuated from the patient flows through the collection chamber and into the suction chamber. According to the patent specification, an object of the invention is to regulate the pressure of the suction chamber relative to the atmosphere by an economical and effective device. This is achieved by applying a vacuum to the suction chamber and selectively bleeding atmospheric air into the chamber. The pressure in the suction chamber is regulated by a suction regulator, which has adjoining compartments. A divider or partition divides the regulator into an upper chamber and a lower chamber, and includes an opening for selectively permitting flow between the chambers. The regulator also includes a closing member biased to a position for closing the opening with force according to the desired suction in the chamber. The patent illustrates the closing member in the form of a ball, but states that other gas port closing means such as hinged doors could be employed to regulate pressure in accordance with the disclosed invention. The regulator allows a medical attendant to select the regulated pressure to be applied to the suction chamber by turning control knobs that actuates a spring, which is attached to and opens the closing member. When the closing member moves away from the closed position, atmospheric air flows from the first chamber to the second, and into the suction chamber. This selective leakage of atmospheric air regulates the pressure in the suction chamber. The disclosed device also includes a damping device for damping the resulting force on the closing member, and thereby modulating its movement. The damping device that is disclosed in the patent figures is a dash pot, that includes a piston attached to the closing member ball and a cylinder that receives the piston in sliding engagement. The following diagram, Figure 1 of the D’Antonio patent illustrates the claimed invention. The claimed mechanical suction regulator, described in detail above, is on the far left of the device: C. The Accused Products While the court may not and will not construe the claim terms by reference to the accused products, a brief description of the Atrium products that Genzyme contends infringe the Elliot and D’Antonio patents is helpful to understand and to give some context to the parties’ claim construction disputes. The accused Oasis and Express devices both contain a collection chamber, a suction chamber, a suction regulator, and a single outlet for connection between the suction chamber and the suction source. The suction regulator that both devices employ is a “dry” mechanical suction regulator. It contains a flat movable valve plug that presses against or covers a valve seat, to prevent atmospheric air from entering the chamber of the regulator that is at suction pressure and flowing through an opening that communicates with the suction chamber. The accused devices also contain a single connection from the device to a source of suction. The newer Express device also employs a mechanical valve as a seal, (i.e., the Express device is a “dry-dry” device— using a dry (mechanical) seal and a dry (mechanical) suction regulator). II. The Law of Patent Claim Construction A. Guiding Principles of Claim Construction The interpretation of patent claim terms is an issue that lies exclusively within the province of the Court. Markman v. Westview Instruments, Inc., 52 F.3d 967, 979 (Fed.Cir.1995) (en banc), aff'd, 517 U.S. 370, 372, 116 S.Ct. 1384, 134 L.Ed.2d 577 (1996). “[I]n interpreting an asserted claim, the court should look first to the intrinsic evidence of record, i.e., the patent itself, including the claims, the specification and, if in evidence, the prosecution history.” Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed. Cir.1996). The supremacy of the claims, specification, and prosecution history in the interpretation of a patent arises from the public notice function of the patent, a record upon which the public is entitled to rely. See Markman, 52 F.3d at 978-79; Vitronics, 90 F.3d at 1583. Claim construction begins with the language of the claims themselves. See Johnson Worldwide Assoc., Inc. v. Zebco Corp., 175 F.3d 985, 989 (Fed.Cir.1999); see also Digital Biometrics, Inc. v. Identix, Inc., 149 F.3d 1335, 1344 (Fed.Cir. 1998) (stating that “[t]he actual words of the claim are the controlling focus”). The words of the claims are generally given their ordinary meaning, unless it is apparent from the patent specification or prosecution history that the inventor used the term with a different meaning. CCS Fitness, Inc. v. Brunswick Corp., 288 F.3d 1359, (Fed.Cir.2002) (noting that courts generally “indulge a ‘heavy presumption’ that a claim term carries its ordinary and customary meaning”); see also Vitronics, 90 F.3d at 1582; Johnson Worldwide, 175 F.3d at 989. After looking to the words of the claims, a court must next review the patent specification. Claims are not interpreted in a vacuum, but “must be read in light of the specification, of which they are part.” Markman, 52 F.3d at 979-80. Indeed, it has been said that the specification “is the single best guide to the meaning of a disputed term.” Vitronics, 90 F.3d at 1582. The specification may assist the court in the interpretation of a claim term “when it expressly defines terms used in the claims or when it defines terms by implication.” Id. In addition, the specification may limit the scope that a patent claim is accorded in circumstances where no broader scope of the claim is described or enabled by the embodiments disclosed therein. See, e.g., Kraft Foods, Inc. v. Int’l Trading Co., 203 F.3d 1362, 1367-69 (Fed.Cir.2000) (limiting “back panel” to the “rigid” back panel described in every embodiment in the specification and excluding the “flexible back panel of the accused device”); Wang Labs., Inc. v. America Online, Inc., 197 F.3d 1377, 1382-82 (Fed.Cir.1999) (limiting “frame” to “character-based” data frames and excluding the “bitmapped” data frames of the accused device, where specification described only “character-based” frames and the prosecution history distinguished the claims from prior art “bit-mapped” frames); cf. SciMed Life Sys., Inc. v. Advanced Cardiovascular Sys., Inc., 242 F.3d 1337, 1344 (Fed.Cir. 2001) (holding that “[w]here the specification makes clear that the invention does not include a particular .feature, that feature is deemed to be outside the reach of the claims of the patent, even though the language of the claims, read without reference to the specification, might be considered broad enough to encompass the feature in question.”). A court should not, however, import a limitation from the specification into the claims, thereby “adding an extraneous limitation appearing in the specification” to the patent claims. Internet America, Inc. v. Kee-Vet Labs., Inc., 887 F.2d 1050, 1053 (Fed.Cir.1989). The final category of intrinsic evidence that must be considered by the court is the prosecution history, which contains the record of proceedings between the inventor and the Patent and Trademark Office. See Vitronics, 90 F.3d at 1583. Where the inventor disclaims certain claim coverage to distinguish a prior art reference, “the prosecution history limits the interpretation of claim terms so as to exclude any interpretation that was disclaimed during prosecution.” Southwall Techs., Inc. v. Cardinal IG Co., 54 F.3d 1570, 1576 (Fed.Cir.1995); see also Ballard Medical Prods, v. Allegiance Healthcare Corp., 268 F.3d 1352, 1359 (Fed.Cir.2001) (“[a]n inventor may use the specification and prosecution history to define what his invention is and what it is not — particularly when distinguishing the invention, over prior art.”). If the intrinsic evidence of record is insufficient to resolve ambiguity in a disputed claim term, the court may then resort to extrinsic evidence, such as expert testimony, inventor testimony, or prior art. Vitronics, 90 F.3d at 1583. The court may also consider “trustworthy” extrinsic evidence such as dictionaries or technical treatises, even when the patent itself is clear, to ensure that its claim construction is not inconsistent with “clearly expressed, plainly apposite, and widely held understandings in the pertinent technical field.” Pitney Bowes, Inc. v. Hewlett-Packard Co., 182 F.3d 1298, 1309 (Fed.Cir.1999). Courts, however, may not rely on extrinsic evidence to contradict or vary the meaning of claim terms made clear by the intrinsic evidence of record. Vitronics, 90 F.3d at 1583-84. B. Construction of Means-Plus-Function Claim Limitations A number of the asserted claims of the patents-in-suit include limitations drafted in “means-plus-funetion” form, where the limitation does not describe a specific structure, but instead describes a function and claims a “means” for accomplishing that function. Pursuant to 35 U.S.C. § 112, ¶ 6, limitations drafted in means-plus-function form are construed to “cover the [functionally] corresponding structure, material, or act described in the specification and equivalents thereof.” Odetics, Inc. v. Storage Tech. Corp., 185 F.3d 1259, 1266-67 (Fed.Cir.1999). Section 112, ¶ 6 provides a compromise to patentees: patentees may express a limitation in their patent claims “as a means or a step for performing a specified function without the recital or structure ... in support thereof;” such a claim, however, will not be interpreted to cover all structures ... which would perform that function, but only “the corresponding structure ... described in the specification and equivalents thereof.” 35 U.S.C. § 112, ¶ 6; see also J & M Corp. v. Harley-Davidson, Inc., 269 F.3d 1360, 1367 (Fed.Cir.2001) (“the scope of such [means plus function] claim language is sharply limited to the structure disclosed in the specification and its equivalents”). The duty to link or associate structure to a claimed function is the quid pro quo for the convenience of employing the means-plus-function claiming technique of § 112, ¶ 6. B. Braun Medical Inc. v. Abbott Labs., 124 F.3d 1419, 1424 (Fed.Cir. 1997). Determining whether a given claim limitation is subject to § 112, ¶ 6 is a question of law. See Kemco Sales, Inc. v. Control Papers Co., 208 F.3d 1352, 1361 (Fed.Cir.2000). Through a series of cases, the Federal Circuit has established a framework for determining when § 112, ¶ 6 applies to a claim limitation. Micro Chem. Inc. v. Great Plains Chem. Co., 194 F.3d 1250 (Fed.Cir.1999). First, if the word “means” appears in a claim limitation in combination with a function, § 112, ¶ 6 is presumed to apply. See Micro Chem., Inc. v. Great Plains Chem. Co., 194 F.3d 1250, 1257 (Fed.Cir.1999); York Prods., Inc. v. Cent. Tractor Farm & Family Ctr., 99 F.3d 1568, 1574 (Fed.Cir.1996). This presumption arises because “the use of the term ‘means’ has come to be so closely associated with ‘means-plus-function’ claiming that it is fair to say that the use of the term ‘means’ ... generally invokes section 112(6).” Greenberg v. Ethicon Endo-Surgery, Inc., 91 F.3d 1580, 1583 (Fed.Cir. 1996). Additionally, if a claim recites “means” language, but does not include sufficient structure to perform the function, it is interpreted as a means-plus-function claim under § 112, ¶ 6. See, e.g., Wegner Mfg. Inc. v. Coating Mach. Sys., Inc., 239 F.3d 1225, 1232 (Fed.Cir.2001) (holding that “air circulation means” was subject to § 112, ¶ 6, because it recited the function of “circulating through said reel,” without reciting any structure for performing that function). Second, the presumption that § 112, ¶ 6 applies to claim terms using the term “means” may be overcome — and the claim term should not be construed as a means-plus-function limitation — if the claim contains a sufficiently detailed recitations of structure, material, or acts to perform the claimed function. See Personalized Media Comms. v. Int’l Trade Comm., 161 F.3d 696, 704 (Fed.Cir.1998); see also Sage Prods, v. Devon Indus., Inc., 126 F.3d 1420, 1427-28 (Fed.Cir.1997) (“[W]here a claim recites a function, but then goes on to elaborate sufficient structure, material, or acts within the claim itself to perform entirely the recited function, the claim is not in the means-plus-function format” even if the claim uses the terms “means”); but see Laitram Corp. v. Rexnord, Inc., 939 F.2d 1533, 1535 (Fed. Cir.1991) (holding that structural description that served merely to further specify the function of the recited means did not take the claims outside the scope of § 112, ¶ 6). Third, the presumption that § 112, ¶ 6 applies to a claim limitation using the term “means” may also be overcome if the limitation does not link the “means” to a function. See York, 99 F.3d at 1574 (holding that claim with a “detailed recitation of structure” but no connection to any function was not subject to § 112, ¶ 6); see also Rodime PLC v. Seagate Tech., Inc., 174 F.3d 1294, 1303 (Fed.Cir. 1999) (holding “positioning means” was not subject to § 112, ¶ 6 where the claim recited a detailed list of structural elements). If no function is linked to the “means” in a claim limitation, that claim limitation cannot be a means-plus-function limitation. York, 99 F.3d at 1574. Finally, if a claim element does not use the word “means,” it is presumed to fall outside § 112, ¶ 6. Micro Chem., Inc., 194 F.3d at 1257. Such claim limitations, however, may still be subject to § 112, ¶ 6, even if the limitation does not use the word “means,” where the limitation is written in functional terms and does not recite sufficient structure to describe the performance of that claimed function. See, e.g., Id.; Mas-Hamilton Group v. LaGard, Inc., 156 F.3d 1206, 1213-15 (Fed.Cir.1998) (holding that “lever moving element” and “movable link member” were means-plus-function limitations, even though the term “means” was not used in claims, because the limitations did not recite definite structure and did not gave generally understood structural meanings in the art). Once the court has determined that a claim element is subject to § 112, ¶ 6, the court must first identify the claimed function, and, second, determine the corresponding structure disclosed in the specification. See IMS Tech., Inc. v. Haas Automation, Inc., 206 F.3d 1422, 1430 (Fed.Cir.2000); Micro Chem., 194 F.3d at 1258. To determine the appropriate structure, the court should look not only to the specification, but to the prosecution history, as patentees will be es-topped from asserting an interpretation of a means-plus-function claim that would be broad enough to cover a prior art reference that the patentee disclaimed coverage of during prosecution. Alpex Computer Corp. v. Nintendo Co. Ltd., 102 F.3d 1214, 1221 (Fed.Cir.1996) (“positions taken before the PTO may bar an inconsistent position on claim construction under § 112, ¶ 6”); see also Ballard, 268 F.3d at 1361. III. Claim Construction of the Elliot Patents A. The Parties’ Positions Before launching into a legal discussion that necessarily includes a detailed review of the claims, specifications, and relevant portions of the prosecution histories of the patents-in-suit, the court will briefly attempt to summarize the parties’ positions regarding the proper claim construction of the disputed claim terms. This will give some context to the sections that follow. 1. Disputed Claim Terms The parties dispute the following claim terms in the Elliot patents. • “waterseal” and “underwater seals” — ■ as used in Elliot ’844, claims 5 and 6, Elliot ’346, claims 5 and 11, and Elliot ’370, claims 1 and 6. • “one-way waterless valve means” and “one way valve seal” — as used in Elliot ’844, claims 5, 6, 12, 13, 15, 16, and 21, Elliot ’346, claims 5 and 11, Elliot ’370 claims 1 and 6. • “means defining a flow path” — as used in Elliot ’844, claims 5, 6, and 21, Elliot ’346, claims 5 and 11. • (i) “U-shaped fluid path,” (ii) “air-leak indicator means,” (iii) “transparent U-tube,” and (iv) “combination negative pressure indicator and air leak detector assembly”' — as used, respectively in (i) Elliot ’844, claims 5 and 6; (ii) Elliot ’844, claim 21, and Elliot ’346 claims 5 and 11; (iii) Elliot ’370, claims 1 and 6; and (iv) Elliot ’856, claims 2, 3, and 4. 2. Genzyme’s Position on Disputed Terms of the Elliot Patents Genzyme submits that a “one way valve” refers to a type of valve, also known as a check valve, that allows the flow of fluid in one direction but prevents the flow in the reverse direction. It ascribes the same meaning to the term “one-way valve means.” Genzyme also asserts that a “waterless valve” is a valve in which water or fluid is not used to serve as a valve. Last, Genzyme contends that both the term “flow path” and the phrase “means defining a flow path” refer to a path along which air flows between specific points. 3. Atrium’s Position on Disputed Terms of the Elliot Patents According to Atrium, the inventors of Elliot patents did not invent the broad concept of using a one-way waterless valve. Based on the patents’ specifications and prosecution histories, it is Atrium’s position that the scope of the patent should be narrowly limited to the specific structures disclosed. Hence, Atrium urges the court to construe the terms “one-way waterless valve means” and “one-way valve seal” to mean the disclosed high precision flapper-type check valve, which performs the functions of permitting flow out of the air space and of preventing reverse flow back into the collection chamber. Atrium also argues that the term “means defining a flow path” means the disclosed relatively open and straight space above the fluid collection chambers which performs the function of defining a path for fluids to flow from the inlet to the one-way valve. As for the terms “waterseal” and “underwater seals,” while Genzyme did not take a position on the claim terms “water-seal” or “underwater seals” in its opening brief, Atrium asserts that these terms both mean a fluid-filled structure that allows air to escape from the patient and prevents back flow of air to the patient under certain circumstances, but which allows back flow to relieve high negative pressure. Additionally, Atrium contends that the terms “U-shaped fluid path,” “air leak indicator means,” “transparent U-tube,” and “combination negative pressure indicator and air leak detector assembly” all mean an air leak detector or U-tube that is not a water seal. B. The Court’s Claim Construction of the Elliot Patents’ Terms 1. “one-way valve” and “one-way ... valve means” The terms “one way valve” and “one way ... valve means” are used in a number of the asserted claims in the Elliot patents-in-suit. Claim 1 of the ’856 patent, for example, discloses a “one-way valve” seal downstream of the negative pressure indicator and air leak detector assembly acting as a seal to prevent air from entering back into the air leak detector, but permitting air from the air leak detector to flow out the valve seal. Similarly, claim 1 of the ’346 patent, discloses a “one-way waterless valve means associated with the fluid collection chamber and being operative, unaided by water seals, to permit air to flow out of the air space while preventing reverse flow back into the collection chamber.” Genzyme proposes the these terms be construed to mean “a type of valve, also known as a check valve, that allows the flow of fluid in one direction but prevents flow in the reverse direction.” Genzyme submits that this claim term, despite the use of the term “means” in some instances, should not be construed as a means-plus-function claim limitation because the term “one-way valve” is a commonly understood term in the chest drainage industry and, thus, itself conveys a sufficiently definite structure. See Personalized Media Comms., 161 F.3d at 704; Sage Prods., 126 F.3d at 1427-28. Genzyme urges the court to accord the term “one-way valve” its ordinary and accustomed meaning as a check valve. A check valve, is defined by Webster’s Third New International Dictionary (1981 ed.) as “a valve that permits flow in one direction but prevents a reverse flow.” Atrium, on the other hand, focusing specifically on the claim term “one way waterless valve means,” contends that these terms are subject to § 112, ¶ 6. It argues that the term “one way valve” does not have a well known structure, but is defined simply by the function that it performs. Thus, while Genzyme argues that the phrase “one-way valve” is a description of a structural type of valve, Atrium argues that it is merely a functional description of a valve and contends that these claim terms are means-plus-function limitations. Atrium argues that the function associated with claim limitation at issue is “preventing reverse flow back into the collection chamber,” while the corresponding structure is the “high precision flapper-type check valve” that is disclosed in the invention. In response, Genzyme argues that if the court accepts Atrium’s arguments and finds that this term to be a means-plus-function limitation, the corresponding structure is not a “high precision flapper-type check valve,” but more broadly a “check valve” and its structural equivalents. The court will begin by determining whether the claim term at issue is drafted in means-plus-function form. If the court finds that it is, the court must next determine the associated function and corresponding structure. Otherwise, the court need only define the term itself. Atrium bases its contention that the court should construe the “one-way valve” and “one-way ... valve means” as means- - plus-function limitations on four arguments. First, Atrium argues that because the word “means” appears in the phrase “one-way waterless valve means” along with a recited function of “preventing reverse back flow into the collection chamber,” a presumption arises that § 112, ¶ 6 applies. Second, Atrium argues that the “one-way valve means” limitations do not include any structure to perform the recited function of “preventing back flow” which could take the limitation out of the scope of § 112, ¶ 6. See, e.g., Wenger Mfg., Inc. v. Coating Mach. Sys., 239 F.3d 1225 (Fed. Cir.2001) (holding that “air circulation means” was subject to § 112, ¶ 6, because it recited the function of “circulating air through said reel,” without reciting any structure for performing that function); Cortland Line Co. v. Orvis Co., 203 F.3d 1351, 1357 (Fed.Cir.2000) (holding that “means for connecting said second end plate to said first spool axle” was subject to § 112, ¶ 6, because it used the term “means” without specifying any structure for performing the stated function). Third, Atrium argues that the recitation of “valve” in the claim limitation is not a detailed recitation of structure sufficient to perform the recited function, and thereby avoid the application of § 112, ¶ 6, because there are many different types structures that can serve as one-way valves. See Laitram Corp. v. Rexnord, Inc., 939 F.2d 1533, 1535 (Fed.Cir.1991) (holding that structural description that served merely to further specify the function of the recited means did not take the claims outside the scope of § 112, ¶ 6); Unidynamics v. Automatic Prods. Int’l, Ltd., 157 F.3d 1311, 1319 (Fed.Cir.1998) (holding that “spring means tending to keep the door closed” did not connote sufficient structure to rebut the presumption that § 112, ¶ 6 applied). Last, Atrium notes that several courts that have had the opportunity to construe claim limitations involving the phrase “valve means” have interpreted the claims as a means-plus-function limitation. See, e.g., Ballard, 268 F.3d at 1359; Schawbel Corp. v. Conair Corp., 122 F.Supp.2d. 71, 79 (D.Mass.2000); Utah Medical Prods., Inc. v. Clinical Innovations Assoc., Inc., 79 F.Supp.2d. 1290, 1307-08 (D.Utah 1999). In response, Genzyme argues that while the claim terms include the word “means,” they include sufficient structure to perform the required function, because the phrase “one-way valve” has a specific structural meaning to those skilled in the art. According to Genzyme, this distinguishes the phrase at issue from the above cases cited by Atrium. Genzyme thus reasons that because the claim terms impart sufficient structural detail, they are not means-plus-function limitations. See TurboCare Div. of Demag Delaval Turbomachinery Corp. v. General Electric Co., 264 F.3d 1111 (Fed.Cir.2001) (holding that “compressed spring means” referred to a particular type of device and that therefore, the district court erred in construing the claim term as a means-plus-function element); Greenberg v. Ethicon Endo Surgery, Inc., 91 F.3d 1580, 1583 (Fed.Cir.1996) (construing the term “detent mechanism” as not invoking § 112, ¶ 6, because it is generally understood in the mechanical arts to describe structure); see also Personalized Media Comm., 161 F.3d at 704; Sage Prods., 126 F.3d 1420. The question of whether this element is a means-plus-function limitation turns on whether the phrase “one-way valve” connotes structure to those of ordinary skill in the art. CCS Fitness, 288 F.3d at 1369. Atrium, citing to the declaration of its expert, Dr. Roger D. Kamm, argues that it does not connote sufficient structure, but only describes a function. Dr. Kamm opines in his affidavit that: The term “valve” does not have a generally understood structural meaning in the art, but instead has a broad range of potential structures. The other words in the claim limitations associated with the “valve means” are functional and do not structurally define the valve means, e.g. “one-way,” ... “operative to prevent reverse flow,” etc. These additional functional terms do not impact structural definition to the valve means. Atrium argues that this conclusion is further supported by the above cited Federal Circuit cases, Laitram Corp. v. Rexnord, Inc., 939 F.2d at 1535 and Unidynamics, 157 F.3d at 1319. Genzyme, on the other hand, cites to numerous sources, including Atrium’s own documents, non-party publications and testimony, expert testimony, and the specifications and prosecution histories of the patents-in-suit to establish that one-way valve is a well known structural term of art in the chest drainage field. In order to establish that the term “one-way valve” is a well understood phrase that connotes structure, Genzyme first notes that Atrium, in its own regulatory and technical documents describes its valves as one-way valves. For example, in its FDA submission regarding its Express product, Atrium told the FDA that “[t]he water seal chamber incorporates a one way check ... valve instead of a water column” and interchangeably referred to one-way valves as “check valves.” Similarly, in Atrium’s press releases and product release brochures, Atrium describes the Express device as employing a “mechanical one-way valve.” Genzyme next points to Atrium’s training manual for the Express device, which describes the “state-of-the-art vacuum protection valve” used within the device as a “mechanical one-way valve.” Genzyme also cites to chest drainage industry articles that refer to “one-way valves.” Along the same lines, it notes that its experts, along with James Brost, the president of a leading valve manufacturing company for the chest drainage industry, also agree that a “one-way valve” is also “known as a check valve” and that “one-way valve is a commonly understood term and is defined as a valve that allows flow in one direction but prevents reverse flow in the opposite direction.” Mr. Brost’s affidavit further states: One-way valves are well-known products in my industry and are available from a number of manufacturers. To a person knowledgeable of valves ... a one-way valve is connotative of a certain structural design, which have a physical barrier that can selectively prevent or allow the flow of a fluid. Such physical barriers used in one-way valves have included since the 1970s the shape of a circular flap or similar sized structure sized to obstruct the reverse flow of fluid through an opening or orifice under desired pressure conditions. Genzyme also notes that numerous patents in the mechanical arts used the phrase “one-way valve” as identifying a type of valve structure. See, e.g., U.S. Patent No. 4, 100, 735, col. 8, In. 8 (“check valve or a one-way valve”); U.S. Patent No. 4,031,-869, col. 3, lines 41-46 (“The one-way valve 12 ... is a well-known check valve which allows the fluid to flow therethrough in one-direction, but not in the reverse direction.”); U.S. Patent No. 4,242,058, col. 4, lines 4-5 (“one-way valve or check valve ...”). Genzyme also draws support for its proposed construction from the patent specifications and prosecution histories themselves. The Abstract sections of the ’844 and ’346 patents disclose “a check valve effective when connected to receive air from the exhaust port of the bottle to prevent the backflow thereof into the system.” The Preferred Embodiment identifies a “check valve 14” or a “high precision flapper-type check valve” located between the fluid collection chambers and the air chamber. Based on its review of the parties’ arguments and the applicable case law, the court finds that the term “one-way valve” connotes structure and therefore is not a mean-plus-function limitation. While it is true that — like the “detent means” and “detent mechanism” terms construed by the Federal Circuit in Greenberg, 91 F.3d at 1583-the term one-way valve “does not call to mind a single well-defined structure,” as the court indicated in Greenberg, “the same could be said of other commonplace structural terms such as ‘clamp’ or ‘container’. What is important is not simply that [it] is defined in terms of what it does, but that the term, as the name for structure, has a reasonably well understood meaning in the art.” Id. This conclusion also finds support in Federal Circuit’s decision in TurboCare. There, the Federal Circuit held that a claim element should not be construed as a means-plus-function element where both the specification and prosecution history disclose only a specific type of device, and do not use the term at issue to refer broadly to any structure that can perform its function. TurboCare, 264 F.3d at 1121 (construing “compressed spring means” as a “compressed spring” not subject to § 112, ¶ 6, because it is “a type of device with a generally understood meaning in the mechanical arts.”). The Elliot patents do not simply claim a “valve means” that could encompass any valve they are limited to a specific type of valve that has a generally understood meaning in the mechanical arts: a one-way mechanical “check” valve. In addition, the court notes that even if the court had accepted Atrium’s arguments and concluded that “one-way valve means” is a means-plus-function element, it nonetheless would not have accepted Atrium’s argument that the corresponding structure would have been the specific “high precision flapper-type check valve.” Instead, it would have reached essentially the same result by concluding that the corresponding structure is a “check valve” and its structural equivalents. Only a simple “check valve” is required to perform the function of the one-way valve means. See Micro Chem., 194 F.3d at 1258 (§ 112, ¶ 6 does not “permit incorporation of structure from the written description beyond that necessary to perform the claimed function”); see also Intel v. Broadcom, 172 F.Supp.2d. 515, 534-35 (D.Del.2001). Therefore, the court concludes that the terms “one-way valve means” and “one-way valve” mean “a type of valve, also known as a check valve, that allows the flow of fluid in one direction but prevents flow in the reverse direction.” 2. “waterless” The parties do not appear to dispute this term. Genzyme’s claim construction brief, “for completeness,” states that the meaning of a “waterless valve,” quite simply, is “a valve in which water or fluid is not used to serve as a valve.” This definition is consistent with the plain meaning of “waterless.” The statements of the inventor to the patent examiner during the prosecution of the parent application to the ’844 patent also support this definition. Dr. Elliot stated, in a response to the patent examiner, that “it is plain from the application and applicant’s previous remarks that the ‘waterless valve means’ is intended to define a valve in which water or fluid is not used to serve as a ... valve.” Atrium does not submit an independent definition of the term “waterless.” Therefore, the court will adopt Gen-zyme’s proposed definition. “Waterless” in the context of the phrase “waterless valve” means “a valve in which water or fluid is not used to serve as a valve.” 3. “means defining a flow path between the inlet tube and said one-way waterless valve” The term “flow path” is used in various claims of the Elliot patents. Some claims use the “means defining” language, while others do not. The parties again sharply dispute whether these claim terms — “means defining a flow path” and “flow path”-invoke § 112, ¶ 6. Atrium contends that “means defining a flow path” is a means-plus-function claim limitation whose function is “defining a flow path for fluids to flow from the inlet to the one-way valve” and whose corresponding structure is “the disclosed relatively open and straight space above the fluid collection chambers.” Atrium argues that this claim term is drafted in means-plus-function form because (i) the term “means” appears; (ii) the term “means” is associated with the claimed function of “defining a flow path;” (iii) the claim term does not include any structure to perform the recited function of “defining a flow path.” In addition, Atrium relies on the latter of the above arguments to support its contention that the term “flow path” is a means-plus-function limitation, even in those claims where the term “means” is not used. Genzyme submits that the term “flow path” means “a path along which air flows between specific points,” arguing that in the context of the claims and specifications of the asserted patents, this meaning is apparent. It argues that the term “means defining a flow path” should have the same meaning, because that phrase is not a means-plus-function limitation. In support of this proposition, Genzyme contends that (i) the term “flow path” is readily understood to mean the path along which air flows between distinct points; (ii) the term “defining” does not constitute a function, within the meaning of § 112, ¶ 6; and, (iii) regardless of whether “defining” constitutes a function, the boundaries of the flow path are clearly defined by the recited structure in the claims themselves of an inlet and a one-way valve. The court finds that the claim term “means for defining a flow path,” as used in the claim phrase “means defining a flow path between the inlet tube and said one way waterless valve,” is not a means-plus-function limitation. While the phrase employs the term “means for,” the court disagrees that “defining a flow path” is a function that corresponds to the means language. This is because the flow path itself is not functionally defined; rather, it is sufficiently defined in the claims by the recited structure of an inlet and a one-way valve. The ordinary meaning of flow path is “a path along which air flows between distinct points.” Where the end points are recited in the claims, the claim element is sufficiently structurally described. Further, while Atrium .asserts that the term “flow path” does not have a generally understood structural meaning in the art, the court sees no reason not to define this term in accordance its plain and ordinary meaning. In analyzing whether “defining” is a function that brings this claim limitation under § 112, ¶ 6 and whether there is a sufficiently disclosed structure in the claims, both parties cite Wenger Mfg., Inc. v. Coating Mach. Sys., 239 F.3d 1225 (Fed. Cir.2001). In Wenger, 239 F.3d at 1237, the Federal Circuit affirmed the district court’s holding that the claim term “means for defining a plurality of separate product coating zone” was not subject to the statutory means-plus-function provision. WTiile the holding that “means for defining” was not a means-plus-function limitation in the patent at issue in Wenger does not necessarily translate to a similar conclusion as to the “means for defining” limitation at issue in the Elliot patents, a review of Wenger is instructive. There, the court stated that although a presumption arises that § 112, ¶ 6 applies, because of the use of the term “means,” see Personalized Media, 161 F.3d at 703, it was “unclear whether there is any function recited that corresponds to the word ‘means.’ ” Wenger, 239 F.3d at 1237. The court went on to conclude that even if the function of “defining” were the function that corresponds to the word “means,” § 112, ¶ 6 would not apply because the claim recites structure that “defines” (i.e., establishes the boundaries of) the claimed separate product coating zones. Id. Specifically, the court found that the claimed “separate product coating zones” were defined by the structural recitation of spray nozzles directed toward the sidewall of the reel and spaced longitudinally along the reel. Id. In this case, the court finds that the term “defining” is not a functional term. The term “defining,” as used in the relevant claims, simply indicates that the path is described in terms of its end points. Moreover, as in Wenger, the boundaries— or end points' — of the flow path are defined by the recited structure of the inlet and one-way valve. See also Sage Prods., 126 F.3d at 1427-28 (“[W]here a claim recites a function, but then goes on to elaborate sufficient structure, material, or acts within the claims itself to perform entirely the recited function, the claim is not in the means-plus-function format” even if the claim uses the term “means”). Therefore, the court agrees with Genzyme that this claim term is not a means-plus-function limitation, and that “means for defining a flow path” has the same meaning as “flow path” — “a path along which air flows between the distinct points.” These distinct points, the inlet and the one-way valve, are recited in each of the claims that use the term “flow path.” The term “flow path” also is used without any “means” language in both claim 1 of the ’370 patent — in the phrase “said inlet tube, air space, and air defining an air flow path” — and in claim 17 of the ’844 patent — in the phrase “said one-way waterless valve means interposed along the flow path defined for the chamber toward the outlet.” Because no means language is used, no function is recited, and the claims set forth the structural boundaries that define the flow path, the court concludes that these claim terms are not governed by § 112, ¶ 6. Therefore, the court will simply accord the term “flow path” the same ordinary meaning it stated above “a path along which air flows between the distinct points.” 4. “water seal” The Elliot patents state that certain alleged shortcomings of the prior art chest drainage systems can be overcome by “eliminating all underwater seals.” Indeed, several claims of the Elliot patents require that the device be a “non-water seal” device, or to operate “unaided by water seals.” This requirement is further confirmed by the prosecution history, which states that the invention is a dry seal that “completely omits the water seal.” Atrium submits that the term “water seal” means “a fluid filled structure that allows air to escape from the patient and prevents back flow of air to the patient under certain circumstances, but which allows back flow to relieve high negative pressure.” It bases this proposed construction partially on the patent specification and partially on the declaration of its expert, Dr. Kamm. The ’844 specification states that “a so-called ‘water-seal’ ... is nothing more than a bottle to receive the drained fluids and air that is partially filled with ... water ... that has the chest drainage tube from the patient opening beneath the surface of this body of liquid so that the air cannot return by the same route.” In addition, Dr. Kamm adds that although a water seal prevents back flow of air to the patient under certain circumstances, under high negative pressure, a water seal allows reverse flow of air to relieve the high negative pressure so that a patient is less likely to be exposed to an unsafe level of vacuum. Atrium’s proposed definition is a synthesis of the two above statements. Genzyme did not submit a proposed definition for this term in its opening brief, but argues in its reply brief that Atrium’s definition is flawed. Genzyme notes that the term “water seal” is clearly defined by reference to the specification alone, and urges the court not to incorporate the second part of Atrium’s proposed definition, drawn from Dr. Kamm’s statement. Genzyme contends that Atrium seeks a construction of “water seal” that is not really a water seal, i.e., that a water seal would allow reverse flow to relieve high negative pressure, in certain circumstances. The court agrees with Genzyme. The court need not supplement the definition of a term with extrinsic evidence, where that term is expressly defined in the patents. In addition to the statement quoted above, the ’844 patent specification adds that “the sole function of the so-called water seals in the prior art chest drainage systems is that of preventing the backflow of air into the patient’s chest cavity.” Moreover, the ordinary meaning of water seal does not reference reverse flow in certain circumstances. Instead “water seal” is defined simply as “a seal formed by water to prevent the passage of gas.” Therefore, because the term “water seal” is expressly defined in the patents and because that definition simply states the ordinary meaning of the term, that definition should control. Vitronics, 90 F.3d at 1582. “Water seal” means “a fluid filled structure that allows air to escape from the patient but prevents the back flow of air to the patient.” The parties may argue as to whether and when such devices break down at certain high negative pressure levels, but that has no bearing on the court’s construction of the meaning of the term itself. 5. “air leak detector,” “air leak detector means,” “U-shaped path,” “U-tube,” and “combination negative pressure indicator and air leak detector” Several claims of the Elliot patents recite an “air leak detector” in various forms. For example, claim 21 of the ’844 patent and all asserted claims of the ’346 patent require “an air leak indicator means;” claims 5 and 6 of the ’844 patent require a “U-shaped fluid path” providing an indication of air passing through; all asserted claims of the ’370 patent require “a U-tube” providing an indication of air leaks; and all asserted claims of the ’856 patent require a “combination negative pressure indicator and air leak detector From Fío. 1 of the ’844 patent Atrium urges the court to adopt an identical definition for each of these claim terms, which is “an air leak detector or U-tube that is not a water seal.” Atrium contends that these claim elements cannot be water seals due to numerous and specific statements in the patent specifications and prosecution history, which so constrain the scope of this element. See e.g., SciMed, 242 F.3d at 1344.; Ballard, 268 F.3d at 1359. Genzyme, which did not address this element in its opening brief, does not dispute that these elements are limited in the patent specifications and prosecution history, but contends, in its reply brief, that Atrium’s analysis is imprecise. The proper construction, according to Genzyme, focuses not on the structures themselves, but on the fluid contained in the structures at issue. Thus, Genzyme submits, the court’s construction should preclude coverage of fluid contained in an “air leak indicator means,” “U-shaped path,” “U-tube,” or “combination negative pressure indicator and air leak detector” that is a water assembly.” As described above, the U-tube structures disclosed in the Elliot patents, when filled with fluid, allow air leaks from the lungs to be observed as bubbles flowing through the fluid. The Figures reproduced below depict the U-tubes (references numbers 62 and 62A) shown in the various Elliot patents. From Fig, 1 of the *370 patent seal effective to prevent the return of air to the patient. To resolve this minor dispute, the court turns to the specifications and prosecution histories of the Elliot patents. The ’844 patent and ’346 patent provides that “the fluid 70 within U-tube 62 is not a water seal effective to prevent the return of air to the patient.” See ’844 patent, col. 5, lines 40-45; ’346 patent, col. 5, lines 42-47. The ’844 specification further explains that no “fluid seal” is present in the claimed' device, “because the fluid in the U-tube is fully capable of passing air in either direction, i.e., back into the patient as’well as out.” ’844 patent, col. 6, lines 5-9. The specification of the ’856 patent, similarly states that “the fluid in the upstream U-tube remains ineffective to form a fluid seal.” ’856 patent, col. 4, lines 17-18. During the prosecution of the ’920 application, which is incorporated by reference into the ’370 and ’856 patents, the applicant distinguished the prior art from the claimed device by stating that “the U-tube 62 of the applicant’s invention is not a water seal.” Similarly, during prosecution of the ’992 application, the applicant again stated that the claimed device “explicitly requires that the one-way waterless valve means [is] operative to prevent reverse flow unaided by underwater seals and comprising the sole means thereof.” It is clear from the above excerpts that the scope of the claimed “air leak detectors” do not include structures which act as water seals, and that the claims should be interpreted so as to exclude from their permissible scope any interpretation that would cover a water seal. The parties do not dispute this. The court must determine, however, whether this limitation should be addressed to the fluid within the structure or to the structure itself. Based on the above statements from the specification and the prosecution history, it seems that the reason that a given air leak detector acts or does not act as a water seal, may be based on the fluid used. Accordingly, the court thinks it is sufficient to simply exclude air leak detectors that act as water seals. The court will adopt the following as its construction of claimed “air leak detectors” (including the claim terms “air leak indicator means,” “U-shaped path,” “U-tube,” or “combination negative pressure indicator and air leak detector”): “an air leak detector or U-tube that does not act as a water or fluid seal.” IY. Claim Construction of the D’Antonio ’531 Patent A. The Parties’ Positions 1. Disputed Claim Terms Before turning to the disputed claim terms of the D’Antonio patent, the court will briefly review the asserted claims of that patent in order to give the proper context to those terms. Independent claim 1 of the D’Antonio patent, which the court reproduces below, discloses: A system for draining fluids from a portion of the body, said system comprising: collection means for receiving fluids from the body, said collection means including an inlet port for admitting fluids from the body to said collection means; a suction chamber communicatable with said collection means, said suction chamber being connectable to a suction source of a suction pressure level; a suction regulator for establishing a desired pressure in said suction chamber, said suction regulator including a first compartment having a first chamber communicating with the atmosphere; a second compartment having a second chamber communicating with said suction chamber and having an outlet for connecting said second compartment and the suction source; first dividing means dividing said first chamber from said second chamber, said first dividing means including an opening for putting said second chamber in communication with said first chamber; first closing means movable between an opening position for opening said opening to admit air at atmospheric pressure into said second chamber, and a closing position for closing said opening to prevent the passage of air at atmospheric pressure into said second chamber; and biasing means for moving said closing means to the closed position when the pressure in said suction chamber exceeds said desired pressure to preferentially apply said suction pressure level to said suction chamber when the pressure in said suction chamber is greater than said desired pressure, and said closing means moving to said open position when the pressure in said suction chamber is less than said desired pressure. ’531 patent, col. 11,1. 49 — col. 12,1.17. Claim 16, also an independent claim, shares a number common elements with claim 1, including the “collection chamber,” “the suction chamber,” and “the suction regulator.” The suction regulator is claimed in claim 16 as having “an opening for admitting atmospheric air to increase the pressure in said suction regulator and closing means for closing said opening.” Claim 16 also discloses a “means for applying a force to said closing means to move said closing means to a predetermined position” and a “damping means for damping the force applied by said closing means.” Claims 17 and 18 are dependent claims that depend from claim 16. Claim 17 discloses “[t]he invention according to claim 16 wherein said damping means comprises a dash pot.” Claim 18 discloses “[t]he invention according to claim 16 wherein said predetermined position is a position closing said opening, and said force applying means comprises biasing means for biasing said closing means to said closing position.” The parties dispute the following claim terms in the D’Antonio patent. • “suction chamber” — as used in claims 1 and 16 of the D’Antonio patent. • “dividing means” — as used in claim 1 of the D’Antonio patent. • “closing means”' — as used in claims 1, 16, 17, and 18 of the D’Antonio patent. • “second chamber communicating with said suction chamber and having an outlet for connecting said second compartment and the suction