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[2022] ZACCP 2
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Hans Sasserath GMBH & Co KG and Another v Advanced Valves CC; In re: South African Patent No. 2005/09552 and infringement thereof (42291/2021; 2005/09552) [2022] ZACCP 2; 2022 BIP 302 (CP); [2022] HIPR 205 (CP) (5 September 2022)
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IN THE COURT OF THE COMMISSIONER OF PATENTS FOR THE REPUBLIC OF SOUTH AFRICA
GDP case no: 42291/2021
Case No/Patent No. 2005/09552
(1) REPORTABLE: YES
(2) OF INTEREST TO OTHER JUDGES: NO
(3) REVISED
In the matter between:
HANS SASSERATH GMBH & CO. KG First Plaintiff
HALOGRAPH (PTY) LTD Second Plaintiff
and
ADVANCED VALVES CC Defendant
In re: South African Patent No. 2005/09552 and infringement thereof
JUDGMENT
AC BASSON, J
Commissioner of Patents
Introduction
[1] The first plaintiff (Hans Sasserath Gmbh & Co. KG) is the proprietor of South African patent 2005/09552 (the patent) and the second plaintiff (Halograph (Pty) Ltd) is a registered licensee of the patent in South Africa (the plaintiffs). The plaintiffs claim that the patent is being infringed by the manufacture and sale by the defendant (Advanced Valves CC) of a vent valve (the AV vent valve – also known as a “vacuum breaker”) in South Africa.
[2] Although the defendant admits that it manufactures and sells the AV vent valve, it denies that the vent valve it manufactures and sells, falls within the scope of the claims of the patent-in-suit and therefore denies infringing the patent. There is no attack on the validity of the patent.
[3] The dispute before the court is whether the defendant’s AV vent valve falls within the scope of one or more of the claims of the patent. Although there are 6 claims, the invention is principally the subject of claim 1. Claim 1 can be divided in various “integers” or features. In respect of claim 1 there are three main disputes. At the heart of the dispute between the parties is whether the small plastic body situated in the vent valve which rises to the top to close the opening to the atmosphere, is a “float” within the meaning of the patent specification. For convenience sake I will refer to this plastic body of the vent valve as the “closing device”.
Legal principles relating to infringement
[4] Section 45 of the Patents Act[1] explains that the effect of a patent is to grant to the patentee in the Republic of South Africa, for the duration of the patent, the right to exclude other persons from making, using, exercising, disposing, or offering to dispose of, or importing the invention, so that he or she shall have and enjoy the whole profit and advantage accruing by reason of the invention.
[5] In order to determine whether this right granted to the patentee is being infringed, the court must first determine what it is that was invented and the scope of the patent. In the present matter, this determination hinges, to a large extent, on the interpretation of the word “float” and whether a “hot water system of a drinking water heater” equites to a “geyser” as commonly understood in the South African plumbing environment. Only once content or meaning has been given to the nature and scope of the patent, will the invention be compared with the alleged infringement in order to determine whether the two are in substance the same. The court in Gentiruco AG v Firestone SA (Pty) Ltd[2] explains:
“The main issues in this appeal are such that our very first task is to ascertain the nature of the invention as claimed and its precise scope (see, for example, Veasey's case, supra at p. 280; cf. Frank & Hirsch's case, supra at p. 756E). Accordingly the specification, and especially the claims, have to be construed; it is, after all, the instrument on which the letters patent were applied for and granted and it must therefore necessarily govern those issues.”
[6] Interpreting the nature and scope of the patent claims requires analyzing the following two components of the patent-in-suit: The first is the body of the specification which informs the reader, normally in general terms, how to put the invention into practice. It has been stated that the body of the specification instructs the public on how to carry out the invention once the patent monopoly has ended.[3] The second is a consideration of the claims. This is the more important component of the enquiry and fulfils a separate and distinct function from the body of specification. It is the claims alone that define the patent monopoly,[4] or put differently, the invention. A claim for an infringement and the scope of a claim is assessed with reference to the claim, not the body of the specification. However, having said this, a patent claim may, where there is, for example, uncertainty about what the ambit of a claim is, be interpreted in the context of what is stated in the body of the specification of the patent. The court in Roman Roller CC and another v Speedmark Holdings (Pty) Ltd[5] explains:
“In determining whether a patent claim stakes its monopoly with a sufficient degree of clarity, the Court must view the patent through the eyes of the skilled addressee in the relevant art; and the Court must take into account that such addressee is expected to use reasonable skill and intelligence in interpreting the language of the patent. He is not required to struggle unduly with it, but he must make the best of it and not adopt an attitude of studied obtuseness. If words or expressions in a claim are affected or defined by what is said in the body of the specification, the language of the claims must be construed accordingly. Moreover, uncertainty or ambiguity in a claim may be resolved by what appears in the body of the specification, which may be thus resorted to not only when the language in question has been expressly defined in the body of the specification, but also, in the absence of such definition, where there is material in the body from which the intention of the draftsman can be gathered. Where the words permit it, an interpretation should be adopted which is consistent with the description of the problem to be overcome and the method of doing so described in the body of the specification. Another source of elucidation of apparently unclear language may be the prior art itself. (See generally Helios Ltd v Letraset Ltd 1970 BP 495 (T) at 498G-499B, 500B-G, 503B-C; Letraset Ltd v Helios Ltd 1972 (3) SA 245 (A) at 249H-251B.)”
[7] The enquiry in determining whether an infringement has occurred is neatly summarized by the court in Aktiebolaget Hässle and another v Triomed (Pty) Ltd:[6]
“In Letraset Ltd v Helios Ltd 1972 (3) SA 245 (A) at 274G - H, Van Winsen JA, writing for the Court on that issue, described the nature of the enquiry into infringement as follows:
'The determination of the question as to whether or not plaintiff has proved an infringement of his patent turns upon a comparison between the article or process, or both, involved in the alleged infringement and the words of the claims in the patent. If the article or process falls within the ambit of the claims, properly construed; an infringement is proved. But the article or process will not be regarded as falling outside the scope of the claims if such differences as the comparison may disclose are not matters of any substance. In making the comparison the law looks at the essence of what is contained in the claim and will not allow what is described as the ''pith and marrow'' of the protected invention to be pirated. The evaluation of what is the substance or essence of an invention is a matter for the ''good sense'' of the judicial tribunal seized with the enquiry.'
[8] The enquiry into infringement requires a comparison between the allegedly infringing article or process against the language of the claim. This enquiry will require of a court to construe the language of the claim. Words must be interpreted purposively so as to extract from it the essence, or the essential elements of the invention or as the court so aptly put it in Aktiebolaget[7] the ''pith and marrow'' of the protected invention. In doing so, the court will use its “good sense”. The court continued to say:
“ . . . a patent specification is a unilateral statement by the patentee, in words of his own choosing, addressed to those likely to have a practical interest in the subject matter of his invention (ie ''skilled in the art''), by which he informs them what he claims to be the essential features of the new product or process for which the letters patent grant him a monopoly. It is those novel features only that he claims to be essential that constitute the so-called ''pith and marrow'' of the claim. A patent specification should be given a purposive construction rather than a purely literal one derived from applying to it the kind of meticulous verbal analysis in which lawyers are too often tempted by their training to indulge. The question in each case is: whether persons with practical knowledge and experience of the kind of work in which the invention was intended to be used, would understand that strict compliance with a particular descriptive word or phrase appearing in a claim was intended by the patentee to be an essential requirement of the invention so that any variant would fall outside the monopoly claimed.”[8]
[9] At the risk of repeating what is stated in various judgments, the following important principles emerge: Firstly, the court is required to compare the article and/or process which form the subject of the alleged infringement, with the words of the claim. If the articles or process falls within the ambit of the claims, an infringement will have been established. Axiomatically this will require the court to interpret the various integers of the claims. Secondly, the emphasis is on the substance or essence of what is contained in the claim or as the court described it in Aktiebolaget[9] the “pith and marrow”. Thirdly, common sense or good sense informs the court what the essence or substance of the claim is. Fourthly, the language of a claim must be construed purposively. In doing so, a court should guard against getting entangled in a process of “meticulous verbal analysis”. The aim is extracting the essence of the claim. Fifthly, the essential question is
“whether persons with practical knowledge and experience of the kind of work in which the invention was intended to be used, would understand that strict compliance with a particular descriptive word or phrase appearing in a claim was intended by the patentee to be an essential requirement of the invention so that any variant would fall outside the monopoly claimed”.
[10] Bearing in mind that the wording of a claim, properly construed, may well be decisive in interpreting the ambit of a claim, it is, in the present matter, important to undertake an interpretative exercise of the words used in claim 1 of the patent, taking into account that a common sense[10] approach should be preferred in determining what the essence of the patent is.
[11] It is accepted that a person skilled in the art may assist the court in interpreting a difficult or technical term. Where words have no special technical meaning, the court will normally ascribe a natural or ordinary grammatical meaning to the words, read in context.[11] In doing so, a court may have recourse to authoritative dictionaries to assist or give some guidance to a court in determining the meaning of a word or a term. Ultimately, however, it is for the court to determine the meaning of a term or word in the context of the document under consideration (including considering what is stated in the specification) as explained by the court in Monsanto Co v MDB Animal Health (Pty) Ltd:[12]
“The rules relating to the interpretation of patents have often been stated and do not need any reformulation. The problem lies in their sensible application in any given case. For present purposes the following rules as they appear in Gentiruco AG v Firestone SA (Pty) Ltd 1972 (1) SA 589 (A) at 614A - 616D may be emphasised: (a) a specification should be construed like any other document, subject to the interpreter being mindful of the objects of a specification and its several parts;
(b) the rule of interpretation is to ascertain, not what the inventor or patentee may have had in mind, but what the language used in the specification means, ie what the intention was as conveyed by the specification, properly construed; (c) to ascertain that meaning, the words used must be read grammatically and in their ordinary sense; (d) technical words of the art or science involved in the invention must also be given their ordinary meaning, ie as they are ordinarily understood in the particular art or science; (e) if it appears that a word or expression is used, not in its ordinary sense, but with some special connotation, it must be given that meaning since the specification may occasionally define a particular word or expression with the intention that it should bear that meaning in its body or claims, thereby providing its own dictionary for its interpretation; (f) if a word or expression is susceptible of some flexibility in its ordinary connotation, it should be interpreted so as to conform with and not to be inconsistent with or repugnant to the rest of the specification; and (g) if it appears from reading the specification as a whole that certain words or expressions in the claims are affected or defined by what is said in the body of the specification, the language of the claims must then be construed accordingly.”8
[12] Two qualifications were added by the court in Monsanto[13] of which only one is relevant in this matter. The court explains when a court may resort to authoritative dictionaries and whether that is permissible:
“Two qualifications - if they are indeed qualifications - may be added. The first relates to the reference to the 'ordinary meaning' of words. In Fundstrust (Pty) Ltd (in Liquidation) v Van Deventer 1997 (1) SA 710 (A) at 726H - 727B, Hefer JA said this:
'Recourse to authoritative dictionaries is, of course, a permissible and often helpful method available to the Courts to ascertain the ordinary meaning of words (Association of Amusement and Novelty Machine Operators and Another v Minister of Justice and Another 1980 (2) SA 636 (A) at 660F - G). But judicial interpretation cannot be undertaken, as Schreiner JA observed in Jaga v Dönges NO and Another; Bhana v Dönges NO and Another 1950 (4) SA 653 (A) at 664H, by ''excessive peering at the language to be interpreted without sufficient attention to the contextual scene''. The task of the interpreter is, after all, to ascertain the meaning of a word or expression in the particular context of the statute in which it appears (Loryan (Pty) Ltd v Solarsh Tea and Coffee (Pty) Ltd 1984 (3) SA 834 (W) at 846G ad fin). As a rule every word or expression must be given its ordinary meaning and in this regard lexical research is useful and at times indispensable. Occasionally, however, it is not.'”
[13] And, as was pointed out by the court in De Beers Industrial Diamond Division (Pty) Ltd v Ishizukaq[14] -
'A dictionary meaning of a word cannot govern the interpretation. It can only afford a guide. And, where a word has more than one meaning, the dictionary does not, indeed it cannot, prescribe priorities of meaning. The question is what is the meaning applicable in the context of the particular document under consideration.”
[14] The court in Multotec Manufacturing (Pty) Ltd v Screenex Wire Weaving Manufacturers (Pty) Ltd[15] likewise cautioned against a too "textual” approach which may result in a court overlooking the important question which is whether an infringement of the substance of the invention has taken place: Was the substance of the invention “pirated”?
“It is true that it is in the claims that a patentee stakes out and defines his monopoly; and that the claims must be looked at in order to determine whether an infringement has taken place. But by peering too closely at the language of a claim the Court may overlook an infringement which takes the substance of the invention…As was pointed out by WILLS J in The Incandescent Gas Light Co Ltd v The De Mare Incandescent Gas Light System Ltd and Others (1896) 13 RPC 301 at 330, in a passage which was quoted with approval in Birmingham Sound Reproducers Ltd v Collaro Ltd 1956 RPC 232 at 242 - 3, and by SCHREINER JA in Frank & Hirsch (Pty) Ltd v Rodi & Wienenberger Aktiengesellschaft 1960 (3) SA 747 (A) at 762:
‘... it is seldom that the infringer does the thing, the whole thing, and nothing but the thing claimed by the specification. He always varies, adds, omits, and the only protection the patentee has in such a case lies, as has often been pointed out by every court, from the House of Lords downwards, is the good sense of the tribunal which has to decide whether the substance of the invention has been pirated.’
In this context it is often said that an infringer who takes the "pith and marrow" of the invention commits an infringement even though he omits an unessential part or substitutes for that part a mechanical equivalent. As it was put by SCHREINER JA in the Frank and Hirsch case supra at 762F - G:
‘It may be that analysis may be overdone in this matter but, taking that risk in an effort to clarify my own thoughts on the subject, I assume that A, B and C are essential features of an invention as claimed and that D, though mentioned in the claim, is in fact not an essential feature. If the alleged infringer omits A or B or C in his apparatus (whether or not he substitutes something else for what is omitted) he does not infringe the patent. To infringe he must take the whole of the essentials of the invention. So far as D is concerned it does not matter what he does. If he has taken A and B and C he has infringed, whether he leaves D out entirely or keeps it in or substitutes a mechanical equivalent for it.’”[16]
[15] Where an infringer thus takes the "pith and marrow" of the invention, it will commit an infringement even in circumstances where it omits an unessential part or substitutes for that part a mechanical equivalent.
[16] In summary therefore, when a court interprets words used in claim 1 of the patent-in-suit (in this case the words “float”; “warm water system” and “drinking water”), whether by attaching an ordinary grammatical meaning to the word or a technical meaning (depending on the context),it must attach an understanding or interpretation of the word with reference to the manner in which it (the patent) is intended to operate and what it is intended to achieve in a particular context.
[17] It is important in the present matter, as already pointed out, to interpret the words used in claim 1 in view of the dispute between the parties as to what meaning should be ascribed to the word “float” and the words “warm water system” of a “drinking water heater”. In brief, the plaintiffs claim that the defendant’s AV vent valve is a “float” and therefore the court should find in favour of the alleged infringement as contemplated in claim 1 of the patent. The defendant disputes this and claims that its vent valve is not a “float”. The plaintiffs submitted that the court should interpret the word “float” in its ordinary grammatical meaning (with reference to some dictionary definitions), whereas the defendant submitted that a more technical meaning should be ascribed to the word “float”. The plaintiffs further claim that a “warm water system” refers to a geyser whereas this is disputed by the defendants based on the assumption that people are not supposed to drink water from a geyser. I will return to these debates in more detail.
Expert evidence
[18] Expert evidence by a person skilled in the art, is undoubtedly helpful to a court, but not decisive. As such an expert may explain technical terms to the court and in general provide guidance to the court particularly in respect of technical concepts. The role of the expert is therefore not to interpret the patent as this ultimately is a question reserved for the court as explained by the court in Gentiruco:[17]
“The area of the territory in which in cases of this kind an expert witness may legitimately move is not doubtful. He is entitled to give evidence as to the state of the art at any given time. He is entitled to explain the meaning of any technical terms used in the art. He is entitled to say whether in his opinion that which is described in the specification on a given hypothesis as to its meaning is capable of being carried into effect by a skilled worker. He is entitled to say what at a given time to him as skilled in the art a given piece of apparatus or a given sentence on any given hypothesis as to its meaning would have taught or suggested to him. He is entitled to say whether in his opinion a particular operation in connection with the art could be carried out and generally to give any explanation required as to facts of a scientific kind. He is not entitled to say nor is counsel entitled to ask him what the specification means, nor does the question become any more admissible if it takes the form of asking him what it means to him as an engineer or a chemist. Nor is he entitled to say whether any given step or alteration is obvious, that being a question for the Court.”
[19] The plaintiffs led the evidence of Mr. Strauss as its expert witness and the defendant led the evidence of Mr. Fourie as its expert. Both witnesses have filed expert witness statements. Although the defendant accepted that Mr. Strauss is a qualified and skilled addressee, the plaintiffs claimed that Mr. Fourie is not a person skilled in the art and is therefore not competent to give evidence regarding the patent-in-suit, more in particular because Mr. Fourie only has experience in hydraulic systems which is a different field to the invention-in-suit.
[20] Mr. Straus is a mechanical engineer with extensive technical and practical experience relating to the use and operation of vent valves used in warm water systems (which he says equates to a geyser) particularly in a plumbing environment. He has, inter alia, worked for the South African Bureau of Standards (SABS) for nearly 24 years between 1994 and 2018. He is a project manager for the Institute of Plumbing in South Africa (IOPSA) and in this roll he manages various technical and administrative projects for them. Some of the projects relate to South African National Standards (SANS), legal requirements and the implementation thereof within the plumbing industry. He is an audit manager for the Plumbing Industry Regulation Board which is responsible for auditing plumbing installations for which certificates of compliance have been issued. He also serves on various technical committees of the SABS. He was extensively involved in creating “Watermark” which is a register for plumbing apparatus that complies with certain prescribed standards. He has also formed his own consulting companies and other businesses focused on providing professional advice and testing services in the plumbing environment. He is also part of the Plumbing Regulatory Board of South Africa. From his curriculum vitae it appears that Mr. Strauss has extensive knowledge of the SANS that govern the installation of plumbing apparatus in South Africa as well as the testing compliance of these apparatus with the relevant standards. He states that he is a skilled addressee relating to the operation and use of vent valves used for airing domestic geyser systems for use with potable water.
[21] Mr. Fourie holds a master’s degree in mechanical engineering. He has knowledge of general engineering principles, including machine, structural and hydraulic design. In respect of hydraulic design. Mr. Fourie has knowledge of flow design, pressure regulating and release devices and fluid flow in general. He does not have experience relating to valves in plumbing. In this regard he conceded that the first time that he was exposed to a vent valve was in the four-month period leading up to the trial. There is also no indication in his curriculum vitae that he has any skills with fluid dynamics which is important in the context of the patents in dispute. It was not disputed that Mr. Fourie’s experience was typically in relation to valves at higher pressure and involving different parts and levels of complexity. The court was also referred to some errors in Mr. Fourie’s first expert summary. The most glaring error is the claim that the closing device in the AV valve “do not include hollows nor are they shaping any particular way, which could cause the bodies to flotd irrespective of the specific gravity values”. This is a glaring mistake as the closing device clearly includes hollows which trap air in use (as was confirmed in evidence). In any event, this feature of the valve became common cause between the parties. In fact, Mr. Fourie also conceded that it was a mistake. In response to the criticism expressed against his expertise, Mr. Fourie stated that the principles regarding the mechanics of the valves used by the defendant in geysers, remain the same.
[22] Whereas Mr. Fourie is, in my view, not nearly as well versed with the operation of valves particularly in the plumbing environment as Mr. Straus, I am not of the view that he should be disqualified out of hand as a person not being skilled in the art. But, having said this, I have approached his evidence with caution particularly in light of some glaring mistakes in his expert report and after having observed his experiments. I will return to the experiments. The fact that Mr. Fourie was only recently (in the four months leading up to the trial), exposed to the defendant’s vent valve, also does not necessarily disqualify him as a person skilled in the art. Ultimately, it is for the court to decide which expert evidence should be preferred over the other. This trite principle is explained as follows in Medi-Clinic Ltd v Vermeulen[18]
“In …. the court held that what is required in the evaluation of the experts' evidence is to determine whether and to what extent their opinions are founded on logical reasoning. It is only on that basis that a court is able to determine whether one of two conflicting opinions should be preferred. An opinion expressed without logical foundation can be rejected. But it must be borne in mind that in the medical field it may not be possible to be definitive. Experts may legitimately hold diametrically opposed views and be able to support them by logical reasoning. In that event it is not open to a court simply to express a preference for the one rather than the other and on that basis to hold the medical practitioner to have been negligent. Provided a medical practitioner acts in accordance with a reasonable and respectable body of medical opinion his conduct cannot be condemned as negligent merely because another equally reasonable and respectable body of medical opinion would have acted differently.”
The defendant’s AV vent valve
[23] To give some context to the patent-in-suit, a few photographs are referred to. Although the photographs only depict the defendant’s red AV vent valve, the AV vent valve also comes in a green colour. Apart from colour of the lid, they differ in that the material used to make the “closing device” is different. This difference in the material is, however, not material to the outcome of this trial.
Photograph 1
[24] Photograph 1 is of the defendant’s pamphlet containing the installation instructions of the AV valve. It depicts a geyser on a tray with the defendant’s AV valve (also commonly known as a “vacuum breaker”) mounted on the end of warm water line downstream of the geyser (at the top on the right-hand side of the photo). As will be explained in more detail, the vent valve has as its purpose to prevent a vacuum being created in a geyser which may result in a leakage as a result of the creation of such a vacuum. According to SANS regulations, the vent valve or vacuum breaker must be installed 300mm above the geyser in a vertical position.
Photograph 2
[25] The second photograph depicts the actual vent valve and more specifically the (contested) closing device. The small red plastic device (which I will refer to as the “closing device” and which the plaintiffs claim is a “float” within the ambit of claim 1) is situated within (“sits” in) the vent valve where it will remain until some damage is caused to the backflow preventer which will cause the red plastic device to rise to the top opening. (I will return to a more detailed description of the purpose of the backflow preventer and what causes the vent valve to rise as this is in dispute between the parties.)
Photograph 3
[26] In photograph 3 the actual closing device is removed from the vent valve. This photograph shows the top part of the floating device. As can be seen, the closing device is a small plastic device. It has four ridges or edges which function, as the evidence showed, to keep the device upright whilst simultaneously allowing for air movement around the device once it starts moving upwardly to close the opening.
Photograph 4
[27] Photograph 4 shows the bottom part of the red plastic closing device. It shows that it has a tubular portion (or cavity) at the bottom that extends vertically outside of the closing device. It also shows that the device has four” protruding legs” (for want of a better description). The evidence was that it is the function of the tubular cavity to allow for air to be trapped inside of the cavity which in turn will increase the buoyancy of the closing device. (I will return to the dispute as to what causes this red device to rise towards the opening with the purpose of closing the opening and thereby preventing water spillage.)
The fifth photograph
[28] Photograph 5 shows the location of the closing device after it has risen to the top. This projection allows for a plumber to immediately see that the closing device is operating which in turn will indicate that the backflow preventer is faulty and should be exchanged or serviced. This functions as a warning signal that there is a problem with the backflow preventer.
The patent
Broad description of the patent: The specifications[19]
[29] As already pointed out, the vent valve is normally arranged at the highest point of a building. In some systems the vent valve also serves for protecting the boiler or water heater against imploding in the case of a pressure drop.
[30] According to the patent specification, the patent-in-suit relates to a “vent valve” for venting a warm water system of a drinking water heater comprising a pipe connection piece with an opening arranged to connect the warm water system with the atmosphere and with a backflow preventer arranged in the pipe connection piece.
[31] Under normal operation, the pressure in a geyser system is 3 to 4 times higher than atmospheric pressure. If there is a drop in pressure in the system which is caused by cooling water under conditions where the system is sealed, for example when the water inflow valve is closed and the system is switched off, that can result in the pressure inside the geyser dropping below atmospheric pressure thereby creating a pressure loss (a vacuum). The vent valve thus aims to alleviate such a drop in pressure by allowing air to enter the system. Where there is such a drop in pressure in the geyser it may result in damaging a geyser even to the extent that it may implode. This may cause extensive water damage, not only to the geyser itself, but to the building or house. The pressure differential in the geyser may also result in water flowing backwards into the geyser from dirty water sources connected downstream of the geyser which may then contaminate the water heating system.
The backflow preventer vs the vent valve (patent-in-suit)
[32] Normally, a backflow preventer or primary valve is installed in geysers that will open to the atmosphere if the pressure of a warm water system (a geyser) drops to below atmospheric pressure thereby creating a vacuum. Air is then allowed to enter the system thereby preventing the generation of such a vacuum. The backflow preventer thus serves to raise the pressure in the geyser to atmospheric pressure. The primary valve is situated below the vacuum breaker and is, in normal circumstances, pressed against a spring so as to close off the geyser. Because the spring is spring-loaded, the valve will normally be closed. In the event of a pressure loss in the geyser, a vacuum will form under the primary valve. Because of the sucking force created by such vacuum, the spring will be forced downwards causing the primary valve to open to allow air to enter which in turn will prevent catastrophic results in the form of severe water leaks. The back flow preventer (or primary valve) is not at issue in the present dispute: It is not a new invention and has been well-known for many years.
[33] But, should the backflow preventer malfunction, water will slowly leak out of the top of the valve and start overflowing onto the ceiling of a house or building. This is then where the vacuum breaker (the invention of the patent-in- suit) provides for a simple solution. By placing a closing device (or vacuum breaker) which is made of a light material above the primary valve, the leaking water will push the closing device up towards the top of the vent valve towards the opening into the atmosphere. This valve in simple terms creates a further seal or added safety measure to prevent the possible outpouring of water on the ceiling:
“It is an object of the invention to provide an inexpensive vent valve of the above mentioned type, where leakage of water is prevented even if the backflow preventer fails.”[20]
[34] It is harmful (“disadvantageous”[21]) with known vent valves that water can leak out of the system in the event that the backflow preventer fails. Without the installation of a further safety measure (such as the vent valve contemplated by the patent-in-suit), this will lead to water damage.
[35] In the South African context, a vent valve is commonly understood to also refer to a “vacuum breaker” or “vacuum relief valve” because its function is to prevent the creation of a vacuum in a geyser in the event the backflow preventer fails which will result in a leakage (through back-siphonage of water) because of the creation of a vacuum.
[36] The patent explains, that in order for the float (the closing device) to achieve this objective, the “weight and consistency of the float is selected such that it floats on a water surface”:
“If the water leaks through the backflow preventer it pushes the float upwards in the direction of the opening. The opening is then closed by the float. The water cannot leak any longer. The float only contacts the water in the case of the failure of the backflow preventer. Otherwise the float is arranged in a dry position. The closing device may, therefore, be of very simple design. During the normal operation the water only reaches the backflow preventer.[22]
[37] The plaintiffs submitted that what therefore makes this invention unique, is the fact that the actual problem - which is the leaking water - is used to create the solution: The closing valve (which it says is a “float”), which is a simple inexpensive piece of light plastic therefore making it an attractive option, is placed in the path of the water leaking into the upper compartment of the valve. The valve, which is capable of being lifted by water, is pushed up by the leaking water into position where it closes the opening and consequently prevents leakage of water. The closing device only contacts with water in the case of a failure of the backflow preventer. Until such time it is arranged in a dry position. The manufacturer therefore created an additional safety feature without the need to include a secondary (and expensive) spring-loaded valve (as in the case of the primary valve). During the normal operation of the geyser, the water only reaches the backflow preventer.
[38] A further feature of this valve (as will be shown when discussing claims 2 and 3) is that, when the device is lifted upwards, the projection (on the upper surface of device) extends out of the cap therefore allowing for a plumber to immediately see that there is a problem with a backflow preventer.[23] In this position -
“Due to its red colour it can immediately [sic] recognised that the float is operating and the backflow preventer must be exchanged or serviced.”
[39] This, according to the plaintiffs, is the essence of the invention.
[40] The defendant valve is a SABS-approved. As such it must comply with the various standards set out in South African National Standard 198:2012 (SANS): “Functional control valves and safety valves for domestic hot and cold water supply systems”. At item A2c the standard states that “the vacuum relief valve ensures that the system is relieved of any vacuum buildup and resulting problems in a hot water system”.
The claims
[41] In order to succeed, the patentee must establish all the essential feature of one claim of the patent.
[42] The following six claims are made in the patent. They each perform a distinct and separate function:
“1. Vent valve for airing the warm order system of a drinking water heater comprising a pipe connection piece with an opening arranged to connect the warm water system with atmosphere and with a backflow preventer arranged in the pipe connection piece, the backflow preventer opening in the direction towards a warm water system, if a pressure loss in the warm water system occurs
characterised in that
on the side of the opening of the backflow preventer a closing device in the form of a float is provided for tightly closing the opening in the pipe connection piece.
2. Vent valve according to claim 1, characterised by a display or other indication device indicating if water is present in a space between the opening and the backflow preventer.
3. Vent valve according to claim 2, characterised in that the display is formed by a projection at the closing device projecting from the close opening.
4. Vent valve according to any of the proceeding claims, characterised in that the backflow preventer is formed by a valve with a valve seat and the valve plate biased by a spring.
5. Vent valve according to claim 3, characterised in that the backflow preventer is cartridge-like insertable into the pipe connection piece.
6. Vent valve for end the warm water system of drinking water heater substantially as herein described with reference to the illustrated embodiment.”
[43] The main dispute centers on claim 1 which is the broadest claim. If the plaintiffs (the patentee) do not establish an infringement in claim1, then none of the other claims will be infringed upon as they are dependent on claim 1.
Claim 1
[44] Claim 1 may be divided into the following “integers” or features:
44.1. A vent valve for airing the warm water system of a drinking water heater comprising
44.2. a pipe connection piece with an opening arranged to connect the warm water system with atmosphere and
44.3. with a backflow preventer arranged in the pipe connection piece,
44.4. the backflow preventer opening in the direction towards the warm water system, if a pressure loss in the warm water system occurs,
44.5. characterized in that on the side of the opening of the backflow preventer a closing device in the form of a float is provided for tightly closing the opening in the pipe connection piece.
Claim 2
[45] In the event of a water leak and once the closing device is in position, the display or indicator due to its red (or green colour) can be seen. This will then serve as an indication to, a plumber for example, that the vent valve needs to be serviced or exchanged due to, some internal damage to the geyser. Claim 2 is a dependent claim in that it adds a further feature to claim 1. Claim 2 is narrower in scope and can only be infringed once an infringement of claim 1 has already been established.
Claim 3
[46] Claim 3 adds a further feature to claim 2, being that the display is formed by a projection at the closing device projecting from the closed opening.
Claim 4 and 5
[47] Claims 4 and 5 are directed at features of the backflow preventer in a valve of claim 1. It is not in dispute that the additional feature of claim 4 are present in the AV valve. Claim 5 is directed at the feature that the backflow preventer is “cartridge-like insertable into the pipe connection piece”.
Claim 6
[48] Claim 6 is directed at the features of the invention as described in the illustrated embodiment. While the plaintiffs maintain that this claim is infringed, the plaintiffs will not seek relief based on it because it is unnecessary to do so.
Disputes between the parties
The disputes in respect of claim 1
[49] The three main disputes between the parties in respect of claim 1 are:
49.1 Firstly, whether a warm water system equates to a geyser.
49.2 Secondly, whether the defendant’s vacuum breaker only opens at a particular pressure loss.
49.3 Thirdly, whether the defendant’s closing device (that little red piece of plastic) is in the form of a “float”.
[50] It is common cause that the defendant’s vacuum breakers are used to vent warm water systems which it describes as a “geyser”. This much is apparent from the defendant’s installation pamphlet[24] which depicts the defendant’s vacuum breaker attached to top of the cold-water supply and hot water supply pipes attached to a “geyser”.
[51] What is disputed by the defendant is that its AV vent valve -
51.1. are intended for use in a “drinking water heater”. In amplification the defendant submitted that a “geyser” in South Africa (in which it uses its vacuum breakers) is not a “drinking water heater” in essence because no one should be drinking water from a geyser.
51.2. have a backflow preventer which opens in the direction of the warm water system “if a pressure loss” in the warm water system occurs. The defendant submitted that the backflow preventer in the AV valve will only open when there is sufficient pressure loss. In other words, if a particular pressure loss occurs; and
51.3. have a closing device in the form of a “float”. The defendant submitted that its closing device is not a float because it’s made from material that has a higher density than water and is lifted into position only as a result of the “drag force” of the water flowing past the backflow preventer (when the preventer is not working): When the closing device is placed in water it will sink.
[52] The defendant conceded that, should the court find that the defendant closing device is in the form of a “float”, then the defendant vacuum breaker would, of necessity, include the integers of claim 2 as both the “float integer” of claim 1 and the “indication integer” of claim two depend on the same question which is whether the defendant’s closing device is in the form of a “float”.
The first dispute: The meaning of a drinking water heater system
[53] In terms of the first claim, the patent-in-suit is for “airing the warm order system of drinking water heater”.
[54] Mr. Strauss had no hesitation in testifying that a “drinking water heater” refers to a “geyser”. He explained that the terminology “drinking water system” does not really exist. He supported this contention by referring to SANS 151 which requires that all water in the geyser must comply with the standard for drinking water. He further explained that every time a geyser gets tested, it is done to make sure that the geyser does not change the properties from potable water quality to non-potable water. He concluded by saying that it is therefore fair to accept it would be fine to drink water from a geyser. Clause 4.6.2 of SANS 151 requires the following:
“Quality of stored water
when tested in accordance with 4.3.2 in SANS 241-1:2011 for class this II uses, the quality and purity of the stored water shall comply with as required for domestic water supplies.”
[55] Mr. Strauss explained that this means in practical terms, that the quality of the water when it is stored in a geyser must comply with the requirement for SANS 241 Part 1 which is the standard for potable water.
[56] Mr. Fourie, on the other hand, testified, with reference to articles which he had downloaded from the Internet and attached his expert’s summary, that it is not advisable, with reference to geysers in America and Australia, to drink water from a geyser and therefore the defendant’s valve does not infringe the patent-in-suit.
[57] In cross examination of Mr. Strauss, it was put to him that the patent-in-suit was intended to be used in a warm water system in something called a “Hydroboil”.
[58] There are various difficulties with Mr. Fourie’s version. Firstly, a so-called “Hydroboil” is a brand name and not a reference to a specific type of product. In this regard Mr. Strauss explained that a Hydroboil refers to an implement which is installed in a domestic setup which would provide boiling water on a continuous basis, similar to what we understand to be an urn. Secondly, if regard is had to the technical field description of the patent-in-suit, it is stated that normally the vent valve is installed at the “highest point of a building. In my view it can hardly be accepted that a “Hydroboil” (which would typically be used for the continuous heating of drinking water in a domestic setup) would be installed at the “highest point of a building”. Also, having regard to the defendant’s installation pamphlet it is clear that the vent valve is installed some 300mm above the geyser. Thirdly and having regard to what is required in SANS 151, it would seem that it is, as a matter of law, required that water that comes out of a geyser must be potable. This makes sense, as it is according to Mr. Strauss common practice in South Africa to connect the water inflow to a geyser from a single source of water which, in itself, must be portable in the sense that it must be capable of being consumed.
[59] In conclusion in respect of this dispute, I am satisfied that the reference to a “warm water system of drinking water heater” can only refer to a geyser. Apart from the fact that I am not persuaded by Mr. Fourie’s evidence, common sense informs that this system refers to a geyser and not to something else.
[60] Having accepted then that “the warm order system” refers to a geyser in the South African setup, I am satisfied that the plaintiff’s vent valve is intended to be used in airing the warm water system of a geyser. Having regard to the defendant’s AV valve, it is similarly an intended feature of its valve to be used in airing the warm water system of a geyser.
Claim 1: Second dispute: The pressure threshold point at which the vent valve opens
[61] Mr. Fourie, although accepting that the backflow preventer opens due to a pressure loss, insisted that the pressure loss had to be between 3kPa or greater.
[62] Mr. Strauss’s disagreed and explained with reference to the standard SANS 198:2012 (which is the standard for vacuum breakers) that a vacuum breaker must operate at a pressure before it reaches 3 kPa, in other words any pressure point ranging from zero to 3 kPa:
“5.3 Vacuum control valves
The design of a vacuum control valve shall be such that, when the valve is tested in accordance with 6.4 the valves shall start to open and a vacuum less[25] than 3kPa +/- 0,1 kPa and at a flow rate of 100 L/min, the vacuum shall be less than 9.0kPa.”
[63] When it was put to Mr. Fourie in cross-examination that the defendant’s valve would have to open at -2.9kPa, he accepted that a valve that does not do so would not comply with SANS 1928.
[64] Despite lengthy evidence on this point, the plaintiffs submitted that it does not matter at what pressure point the defendant’s valve opens, the fact is that it will open if there is a pressure loss. Once is accepted by the defendant that the backflow preventer opens due to a pressure loss, the plaintiff has succeeded with its claim particularly in view of the fact that the patent-in-suit does not stipulate the threshold of the pressure loss that must occur before the vent valve opens.
[65] I agree. The dispute about the specific kPa at which the vent valve will open, is academic simply because claim 1, which provides for a “pressure loss in the warm water system”, does no more than to refer to a pressure loss which will achieve the function of opening the event valve. Also, in view of the fact that SANS 198 requires that the vent valve must start opening in a vacuum between 0 and -1 kPa and the fact that the defendant’s vent valves are SANS compliant, it must be accepted that the AV vent valve falls within what is stated in claim 1 of the patent.
[66] In conclusion, having regard to claim 1, it is not an essential feature of the invention that it must open at a certain pressure point. The fact is, the vent valve rises to close the opening when the backflow preventer fails. This is the essence of the defendant’s vent valve and of the patent-in-suit and it is this essence that the defendant “pirated”.
Claim 1: Third dispute: Is the closure device a float?
[67] Before taking a closer look at the submissions, it is helpful to have regard to how a “float” is defined in ordinary English. In doing so, I am mindful that ultimately it is for the court to decide what the meaning of the term in the context of the patent is irrespective of how a dictionary defines the word. A “float” is defined in the Oxford paper dictionary as:
“1. Rest of the surface of the liquid without sinking 2. Move or be held up in a liquid or the air.”
In the Collins Concise English Dictionary[26] a float is defined as -
“1. To rest or cause to rest on the surface of a fluid or in a fluid or space without sinking: oil floats on water 2. To move or cause to move buoyantly, lightly or freely across the surface or through air, water etc.”
[68] Mr. Fourie testified that a technical meaning should be ascribed to the word “float” and explained that, in light of “fundamental engineering principles” the defendant AV vent valve cannot be regarded as a “float”, hence there can be no infringement of the patent-in-suit. He also explained that since the materials used to make the defendant’s closing device are made from material which has a specific gravity greater than that of water (1.0), the device cannot be regarded to be a “float” because its relative density is greater than that of water. He further testified that where an object (such as the defendant’s AV vent valve) is forced upwardly by water travelling at high velocity, in other words a “ drag force”, cannot be said to be a “float”.
[69] Mr. Strauss disagreed with Mr. Fourie’s theory and explained that the floating device has been designed in such a way that the “effective” density of the device is lower than water. He further explained what “effective” density means with reference to a ship: A ship is made of steel which is much denser than water yet it stays afloat because of its shape and orientation. He testified that similar principles apply to the closing device (the vent valve) at issue in this matter. With reference to the vent valve, he explained that it must be taken into account that the (leaking) water rises from the bottom of the device and that air will be trapped below the device (in the hollow space or cavity[27]) which will in turn changes the effective density of the device so that it is lighter than water and then allows it to float. When water leaks from the backflow preventer, air will thus be trapped inside the cavity (an air bubble) aided by the four protruding legs. The trapped air will make the device lighter and in turn would increase the buoyancy of the closure device in water. The effective density, said Mr. Strauss, is not only the density of the material but the combination of the density of the material and the density of the air trapped in the device.
[70] In respect of the four protruding legs at the bottom of the vent valve outside of the tubular portion, Mr. Fourie initially testified that the protruding legs are just used to make the manufacturing of the plastic body easier. He eventually had to concede in cross-examination that the circular extension with the protruding legs had no manufacturing benefit. Unfortunately, the following exchange in cross-examination did little to install confidence in Mr. Fourie’s expert evidence:
“Mr Marriot: the reason that thing, that that (sic) circular bit extends outwardly from the rest of the body, it is not there by accident. It is there because the designers of this device wanted to ensure that there was a proper bubble created underneath it so that you did not have to rely on drag force to pull it up. You care to comment?
Mr. Fourie: I did not …. I was not advised that was the case. I was advised the hole is there for injection moulding purposes. So if it is there for a bubble, you might be right. But I cannot confirm or not. I have not spoken to the guys. Is there any other reason for that sticking out the bottom?
Mr Marriot: Ja, but you are here as an expert and you have already conceded that you can chop that circular extension off and it will make no difference from the injection moulding perspective. Correct?
Mr Fourie: Ja - no, that I agree.”
[71] Regarding Mr. Fourie’s claim that a drag force will force the closing device upwards. Mr. Straus explained in detail what causes a drag force and why he disagrees with Mr. Fourie that only a drag force will force the closing device upwards. He explained that, in normal circumstances, the water leaking into the cavity will be slow whereas a drag force is associated with speed. This is so because without speed a velocity drag force will not exist. A drag force theory is thus not a feasible explanation as to why the floating device would rise. Firstly, as already pointed out, the leaking water from the backflow preventer will normally be slow and not fast and secondly, if there is a gush of water (which will cause a drag force) everything will be swept away. The patent-in-suit is designed to provide a solution where there is a small leak as is normally the case.
[72] I am not persuaded that, having regard to the context in which the term “float” is used in the patent and the purpose for which the vent valve was designed, that a technical approach to or interpretation of the term is warranted. The court in Multotec[28] cautioned courts against peering too closely at the language of a claim as this could result in a court overlooking an infringement which takes the substance of the invention. The term float means nothing more than to refer to a device (in this case normally situated in a dry position in the vent valve installed in a geyser) that is pushed upwards by water leaking through the backflow preventer to the point where it is pushed into the opening causing the opening to tightly close. That is what the patent says it does and this is what the defendant’s AV valve does. Mr. Fourie in fact accepted this proposition put to him in cross-examination:
“Mr Merrick: …. Would you agree with me that what this invention is really about is using a piece of material which is placed in the cartage above the vent, above the back flow preventer so as to seal the vent valve under the effect of the water causing the leak… Is that a fair characterisation of what this invention sought to achieve?
Mr. Fourie: Yes, because at once there is a leak you would like to stop it. So you use the leak to actually accomplish the final goal.
…
Mr Fourie: It is how you use it is what the difference is.
Mr Merrick: Well yes, well that is your, that is your case. But you agree with me as I understand that you use the problem which is the leaking water to provide the solution which is the closure and all you do is you add a little bit of plastic or whatever it is the flotation device or the closure and to achieve that. He used the problem to achieve the solution, which agreement that?
Mr. Fourie: yes.”
[73] Having conceded that this is a salient feature (or essence) of the invention, the whole debate as to why the closing device is pushed up towards the opening, whether as a result of surface tension or drag force, becomes, in my view, academic. Certainly Mr. Fourie’s explanation with reference to “fundamental engineering principles” is not helpful. There is nothing in the patent specification that supports his interpretation. What is contemplated by the patent is that the “float” must have a “weight or consistency” that enables it to float. And again, this is what the defendant’s closing device does: It is intended to rise with water that seeps through the faulty backflow preventer with the aim of pushing it up towards the atmosphere with the aim of closing the opening and thereby prevent water damage. This is the whole purpose or essence of this invention. The term “float” used in the patent simply refers to a device that rises with or as a result of water entering the upper chamber.
[74] Although I have previously stated that I am not inclined to discard Mr. Fourie out of hand as not being a person skilled in the art, his evidence in respect of why the closing device is not a “float” is flawed. Also, Mr. Fourie relied on the say-so of other people with regard to the shape of the closing device, whereas one would have expected that an expert would make his own observations and form an expert opinion independently. Secondly, having now conceded, although reluctantly, that there is no manufacturing necessity that would explain the protruding legs, the debate as to why the “float” rises become academic. In this regard, I am in agreement with the submission that it should not readily be accepted that designers and manufacturers will incorporate parts which serve no purpose. The tubular portion of the closing devise with its four protruding legs clearly was designed to trap air so that the closing device will rise when water seeps through from the backflow preventer.
[75] In conclusion on this point: The closing devices of the defendant were plainly designed to rise with water seeping through from the backflow preventer and as such they are “floats” within the meaning of the patent.
Experiments
[76] Just a few cursory remarks regarding the numerous experiments that were conducted by both parties in an attempt to prove their respective positions advanced in their expert summaries. I do not intend discussing the experiments in detail because ultimately one has to have regard to the essence of the closing devices and what common sense dictates. In glossing over the experiments, I will invariable repeat some of the findings already arrived at. Briefly, whereas Mr. Strauss persuaded me that the closing device is a float and that it does rise when water slowly leaks underneath it, Mr. Fourie was not able to persuade me through his experiments that the closing device is not a float particularly with reference to the experiment where the closure device was dropped into a glass with water and the other where the closing device was placed in an empty glass and water poured onto the device.
[77] Firstly, in the context of a geyser, the water that pushes the closing device upwards seeps through from beneath, in other words from the direction of the backflow preventer which has failed for some or other reason. The water does not come from above, as was the case in one of Mr. Fourie’s experiment. Mr Strauss who has vast experience in the plumbing industry whereas Mr. Fourie does not, explained that in most cases the water will leak slowly through the backflow preventer. There will, in most cases, not be the “turbulent water” flow that Mr. Fourie required for the device to rise. In most instances where the water flows in slowly, surface tension coupled with the effect of the air bubble will cause the closing device to rise which is consistent with the experiments of Mr. Strauss. Mr. Fourie claimed that it is only where there is turbulent water flow, the device will rise because of the forces created by the velocity of the water rather than surface tension. His theory was, unfortunately debunked by the experiments done by Mr. Strauss. But, as I have concluded, it does not really matter what causes the closing device to rise. The fact is, it does.
[78] Secondly, by adding water from the top of the closing device or by dropping the closing device into the water, Mr. Fourie’s experiment sought to negate the effects of surface tension and reduce the potential for any air bubble to be formed in the cavity. But, this is not what happens in a plumbing environment. The closing device rests in a dry position until such time water seeps through from the backflow preventer into the cavity and causes the device to rise.
[79] Thirdly, Mr. Fourie’s experiments aim to negate the very specific and carefully crafted design of the closing device. It is improbable that the designers would have crafted the tubular portion with the four protruding legs for no purpose at all. It could only have been to allow for an air bubble to be trapped in the tubular portion causing it to become buoyant. And, as already pointed out, Mr. Fourie initially did not even know why the closing device had the tubular portion.
[80] Fourthly, Mr. Fourie added food colouring to the water in some of his experiments to enhance the visibility of the effects of the experiment. The adding of colourants was severely criticized in that chemicals such as propylene glycol and propyl-hydroxy (which are chemicals present in the colouring used in the experiment) are well-known to significantly diminish the effects of surface tension. Whereas the plaintiffs accepted that the surface tension of water play an important role in causing any object to float, changing the chemical composition of the water will reduce surface tension and will result in diminishing the ability of the object to rise. Mr. Strauss countered these experiments with further experiments which showed that the device did indeed rise when water was fed slowly into device. What these experiments showed was that the effects of surface tension coupled with the trapped air bubble, made the closing device to rise.
The warm water factor
[81] Then in cross-examination, it was put to Mr. Strauss that an increase in the temperature of water reduces the effect of surface tension. Further experiments were then done with water at various temperatures. What these experiments set out to do was to demonstrate that the defendant’s closing device is not a “float” because it did not rise in warm water. The temperature of the water that was used in the one experiment was above 70°C (which is exceedingly hot even in the context of a geyser).
[82] In cross-examination, Mr. Fourie was requested to do the same experiment but using water at a lower temperature which is more consistent with the plumbing environment. The defendant’s red closing device rose when water at a temperature of 60oC was slowly fed into the apparatus used for the experiment. What this further experiment showed was that the closing device rose when water was slowly fed into the apparatus used. This again completely debunked Mr. Fourie’s theory that only a drag force can cause the closing device to lift. The same experiment was repeated using the defendant’s green floating device. The device raised when water at a temperature of 45°C was used but not when water was used at temperatures of 50°C and above.
[83] What is, however, an unknown factor as there was no evidence to this effect, is at what temperature the water will be in a geyser in the event of a failure of the backflow preventer. What is also unknown is to what extent water would have cooled down by the time it reaches the vent valve which is located outside of the geyser and at least 300 mm away which may cause the water to cool.
[84] These experiments were however informative in that it gave the court an idea as to how the closing device operated in water. What is ultimately important is that it is the essential function of the defendant’s closing device to rise with water (whether it is as a result of a drag force or as a result of something else) and close the opening to the atmosphere. This is the essence of the patent.
[85] Having regard to the evidence, I am thus persuaded that the defendant’s AV vent valve, infringes claim 1 of the patent-in-suit.
The dispute re-claim 2
[86] Claim 2 introduces a further feature to the floating device in the form of a display or other indication device for indicating that water is present in the space between the opening and the backflow preventer.
[87] Because claim 2 is dependent on the court’s finding whether or not the device is a “float”, and in light of my finding that the closing device is a float, that is the end of the debate in respect of claim 2.
The dispute re-claim 3
[88] Claim 3 introduces a further integer to claim 2 in the form of a display that is formed by projection at the closing device.
[89] Although the defendant argues that the display device is not in the form of a projection which projects from the opening of the vent valve, it has since accepted that the integers added by claim for present in its vent valve and this claim is thus infringed if claim 1 is found to be infringed.
The dispute about claim 4
[90] Mr. Fourie claimed that the backflow preventer is not a “cartridge”. This is not what the claim requires. It only requires that it is “cartridge-like”.
[91] Mr. Strauss identified that backflow preventer as consisting of four separate pieces that are assembled to form the backflow preventer.
[92] The defendant submitted that nothing shows that that the backflow preventer can be assembled into a cartridge.
[93] This is really a red herring because this is not what the patent requires. It only requires that it must be “cartridge-like” which, in my view, has been established.
The dispute re-claim 5
[94] Claim 5 introduces the further integer to claim 4 namely that the backflow preventer is cartridge-like insertable into the pipe connection piece. The defendant argues that its backflow preventer is not a cartridge because it is made from loose parts. Again, this is a red-herring. The patent only requires that it be cartridge-like.
The relief
[94] The plaintiffs sought the relief as set out in the particulars of claim which is for an interdict restraining the defendant from infringing the claims (1-5) of the patent-in-suit and for an order for the delivering up for destruction of the AV vent valve. Paragraphs (c) and (d) provides for an inquiry into the damages suffered as a consequence of the infringement. The parties have not specifically addressed me on this part of the relief but I have included same in my order. Costs should follow the result.
In conclusion
[95] In conclusion, I am satisfied that the defendant’s AV Valve falls within the scope of claims 1 – 5 of the patent and that the defendant infringes that patent-in-suit.
[96] In the event the following order is made:
1. The defendant is interdicted from infringing claims 1 - 5 of South African Patent no 2005/0955 by importing and or manufacturing and/or using and/ or offering to dispose of and/or disposing of in the Republic of South Africa the AV vent valve which falls within the scope of the claims of South African Patent no 2005/09552.
2. The defendant is ordered to deliver up for destruction the AV Vent valves which infringes claims 1 – 5 of South African Patent no 2005/09552.
3. It is ordered that an enquiry into the damages suffered by the plaintiffs as a consequence of the defendant’s infringement of South African Patent no 2005/09552 and the payment by the defendant of the amount of damage found to have been so suffered alternatively, an inquiry into the extent of the infringement and the amount of reasonably royally to be paid in lieu of damages and payment by the defendant of the amount of royalties found to be so payable, be postponed sine die.
4. Should the parties be unable to agree as to the future pleadings to be filed or any other matter relating to the enquiry ordered in terms of paragraph 3 of the order, any party may, on notice to the other party, make application to this court for directions in regard thereto.
5. The defendant is ordered to pay the plaintiffs’ costs including the costs of counsel and the qualifying fees of the plaintiffs’ expert witness.
JUDGE A C BASSON
JUDGE OF THE HIGH COURT
GAUTENG DIVISION OF THE HIGH COURT, PRETORIA
Appearances
For the first and second plaintiffs: Adv Gavin Marriott
Instructed by: Adams & Adams
For the defendant: Adv KD Iles
Instructed by: McCallum Rademeyer & Friedmond
Date of judgment: 5 September 2022
[1] Act 57 of 1978.
[2] 1972 (1) SA 589 (A) at 613 F- H.
[3] Letraset Ltd v Helios Ltd 1972 (3) SA 245 (A) at 249F: “Hence the function of the claim is to inform prospective rivals of the limits of the field denied to them while the patent lasts; and the function of the body of the specification is to instruct the public how to carry out the invention when the field is eventually open.”
[4] Ensign-Bickford (South Africa) (Pty) Ltd and Others v AECI Explosives and Chemicals Ltd 1999 (1) SA 70 (SCA) at 77 H – 78 B.
[5] [1995] ZASCA 78; 1996 (1) SA 405 (SCA) at 35. In that matter there was an attack based on lack of clarity which is not the case in the present matter. The principles expressed in this matter is, however, relevant.
[6] 2003 (1) SA 155 (SCA) at para 7.
[7] Ibid.
[8] Ibid at 159H – J at para 8. A quote from Lord Diplock in Catnic Components Ltd and Another v Hill and Smith Ltd [1982] RPC 183 (HL) at 242.
[9] Ibid.
[10] The court in Multotec Manufacturing (Pty) Ltd v Screenex Wire Weaving Manufacturers (Pty) Ltd 1983 (1) SA 709 (A) at 709 D – E and 721B – H warned against peering too closely at the language of the claim but rather look at the substance of the invention: “It is true that it is in the claims that a patentee stakes out and defines his monopoly; and that the claims must be looked at in order to determine whether an infringement has taken place. But by peering too closely at the language of a claim the Court may overlook an infringement which takes the substance of the invention… As was pointed out by WILLS J in The Incandescent Gas Light Co Ltd v The De Mare Incandescent Gas Light System Ltd and Others (1896) 13 RPC 301 at 330, in a passage which was quoted with approval in Birmingham Sound Reproducers Ltd v Collaro Ltd 1956 RPC 232 at 242 - 3, and by SCHREINER JA in Frank & Hirsch (Pty) Ltd v Rodi & Wienenberger Aktiengesellschaft 1960 (3) SA 747 (A) at 762: "... it is seldom that the infringer does the thing, the whole thing, and nothing but the thing claimed by the specification. He always varies, adds, omits, and the only protection the patentee has in such a case lies, as has often been pointed out by every court, from the House of Lords downwards, is the good sense of the tribunal which has to decide whether the substance of the invention has been pirated."
[11] Letraset Ltd v Helios Ltd 1972 (3) SA 245 (A) para 8 at 250C – D.
[12] 2001 (2) SA 887 (SCA).
[13] Ibid at para 9.
[14] 1980 (2) SA 191 (T) at 192A.
[15] 1983 (1) SA 709 (A).
[16] Ibid at 709 D – E and 721B – F.
[17] Supra fn. 2 at 617 – 618.
[18] 2015 (1) SA 241 (SCA).
[19] Under the technical field of the patent.
[20] Introductory paragraph under the disclosure of the invention.
[21] Word used in the patent.
[22] Patent specification.
[23] Photograph 5 supra.
[24] Photograph 1 supra.
[25] My emphasis.
[26] 2006.
[27] Photo 4 supra.
[28] Supra.