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Pifco Limited v. Philips Domestic Appliances and Personal Care BV, Philips Electronics UK Limited [1998] EWHC Patents 276 (16th December, 1998)
CH 1997 P 5304
IN THE HIGH COURT OF JUSTICE
CHANCERY DIVISION
PATENTS COURT
Mr Justice Pumfrey
BETWEEN
PIFCO LIMITED
Plaintiff- and -
(1) PHILIPS DOMESTIC APPLIANCES AND PERSONAL CARE BV
(2) PHILIPS ELECTRONICS UK LIMITED
Defendants
David Kitchin QC and Richard Meade instructed by Bristows for the Plaintiff
Henry Carr QC and Hugo Cuddigan instructed by Bird & Bird for the Defendants
Hearing date(s): 2, 3, 4 June, 1, 2 October 1998
JUDGMENT
1. I direct pursuant to RSC Order 68 rule 1 that no official shorthand note shall be taken of this judgment and that copies of this version as handed down may be treated as authentic.
DATED 16 December 1998
Introduction
1. This is an action for the infringement of a patent relating to the manufacture of electric kettles. Infringement is denied. There is the usual counterclaim for revocation. The principal claim is a method claim.
2. In this action, the defendants ("Philips") took advantage of the procedure established by the amendment made to Order 104 rule 11 in 1995 to serve a description of the allegedly infringing method of manufacture of their kettle, which is called the Filterline Express. They did this to avoid giving discovery of all documents relating to their method of manufacture, which would have been a difficult and onerous exercise. The purpose of the amendment to rule 11 was to avoid, so far as possible, unnecessary discovery. The case was worked up by both Pifco and Philips on the basis of the description which had been provided by Philips. The skeleton argument presented by Pifco's counsel suggested that there was no factual dispute as to what was happening in the manufacture of the kettle. It quickly became clear during the first day of the trial that there were ambiguities and gaps in the description which were significant to the issue of infringement. By the third day, it was plain that the action would have to be adjourned for an inspection of the allegedly infringing process by the experts retained by both parties, and the preparation of a fresh process description. When the trial resumed, it was plain that its complexion had changed substantially.
3. It is both difficult and pointless to allocate blame for what happened in this case. It does however provide a useful lesson in the preparation of process descriptions. The rule requires a product or process description to include "full particulars of the product or process alleged to infringe, including if necessary drawings or other illustrations." The criterion by which the adequacy of such a description is to be judged is whether it provides enough information for the court to arrive at a yes/no answer to the disputed questions on the issue of infringement. Experience is beginning to suggest that the main problem with product and process descriptions is that they are prone to contain factual inferences without setting out the primary facts from which the inferences have been drawn. This may not matter in non-controversial parts of the description, but otherwise it can give rise to real difficulty. To take an example from this case, there was an issue as to whether the vacuum preload which was used compressed the seal to a significant extent, or whether it was the descending moulding tool and the softened plastic lying it its path which did the job. The description was quite inadequate to answer this question. It turned out that the defendants operated two machines. These functioned in different ways. Not until the experts agreed a description, after the inspection to which I have referred, was it possible to deal satisfactorily with the issue of infringement.
The patent in suit.
4. The title of the patent is "Improvements in heating apparatus". The opening words of the specification reveal that the heating apparatus in question is the sort which has an element, and the patent is concerned (though not exclusively) with water heating apparatus such as electric kettles. The remainder of the description is concerned exclusively with domestic apparatus such as kettles.
5. The particular problem with which the patent is concerned is the replacement in domestic kettles of the traditional sheathed coiled wire electric element with the more modern planar type, which is simply a generally flat sheet of material which is heated either from an element attached to the underside of the plate or by an element incorporated in the material of the plate itself. The evidence was that "planar element" is not a term of art. It encompasses any element generally flat which is intended to form a wall of the container in which liquid is to be heated.
6. If a kettle designer wants to use a planar element in a kettle with a plastic body, he is confronted with the fact that plastics, unlike metal, tend to degrade or soften when heated to temperatures not far in excess of the temperature of boiling water. Obviously the element has to be maintained at a temperature in excess of that of the boiling water. How to do this? The patent provides an answer in claim 1, the features of which are labelled for ease of reference. This division into features is the one used by Mr Dunning, Pifco's expert.
1. A method of attaching a planar electrical element (5) to a vessel (1)
2. whereby the element (5) is integrated in the body of the vessel (1) to form a heating apparatus,
3. the body of the vessel (1) defining an aperture (4) at a position where the element (5) is to be secured thereto
4. and the element (5) comprising a plate capable of covering the aperture,
and characterised in that it comprises the steps of
5. covering the aperture (4) defined by the body of the vessel (1) with the element (5),
6. a sealing means (7, 11, 12, 13) being located around the periphery of the aperture (4)
7. in contact with at least one side of the element (5) and the body of the vessel (1);
8. positioning a securing means (6) on the element (5) on the opposite side thereof to that facing the aperture (4);
9. retaining the element (5) and the securing means (6) in position with the element (5) in contact with the sealing means (7, 11, 12, 13) whilst compressing the sealing means by a predetermined amount;
10. and deforming a portion of the body of the vessel (1) in a region around said aperture (4) in a direction inwardly of the aperture (4) into contact with the securing means (6)
11. to retain the securing means (6) and thereby the element (5) and the sealing means (7, 11, 12, 13) in place with the sealing means under compression.
2. The idea is that a seal is placed around the edge of the aperture which is to receive the element. The element is placed against the seal. A piece of material (the "securing means") is placed on the other side of the element. The seal is then compressed via the element. Some part of the body of the vessel is then deformed to come into contact with the piece of material, so trapping the element and the compressed seal.
7. If the seal is made of heat resistant material (such as silicone rubber) the material of the kettle is protected from direct contact with the hot element.
8. As is often the case, it is important to appreciate what this claim covers. A number of propositions are uncontroversial. The claim is not limited to plastic bodies. It covers metal ones as well. So it covers kettles in which the material of the wall of the kettle does not need protecting from heat, but merely needs a seal against leakage. It also covers a kettle in which the element and body have the same coefficients of thermal expansion, so that there are no problems raised by differential expansion. Features 8, 10 and 11 are vague as to the shape of the securing element. They are also vague as to how much of the body of the container has to be deformed in order to retain the securing element. I turn to the principles of construction.
Construction
9. Both the issues of infringement and the issues of validity give rise to questions of construction. While it used to be the law that the specification is to be construed as if the defendant had never been born, it is not possible either to identify the points of difficulty nor apply the principles by which the scope of the claim is to be ascertained without looking at the thing (whether infringement or invalidating matter allegedly old or obvious) said to fall within that scope. A literal meaning of the claim has to be arrived at, and, if necessary, any variants from that strict, literal meaning present in the alleged infringement (or thing old or obvious) have to be identified. The modern law of construction is set out in the judgment of the House of Lords in Catnic v Hill & Smith [1982] RPC 183 at 242 line 44 ff. The question is whether on a proper construction of the claim in its context in the specification, the patentee intended that strict compliance with any particular descriptive word or phrase was an essential requirement of the invention, so that any variant would fall outside his monopoly, on the assumption that the variant would have no effect upon the way the invention worked and that a skilled man would have appreciated that to be the case. In Kastner v Rizla Ltd [1995] RPC 585, Aldous LJ (with whom the other members of the court agreed) said that the convenient way to approach this question was by way of Hoffmann J's questions in Improver Corp v Remington Consumer Products Ltd [1990] FSR 181 at 189. They are as follows:
1 Does the variant have a material effect upon the way the invention works? If yes, the variant is outside the claim. If no -
2 Would this (ie that the variant had no material effect) have been obvious at the date of publication of the patent to a reader skilled in the art. If no, the variant is outside the claim. If yes -
3 Would the reader skilled in the art nevertheless have understood from the language of the claim that the patentee intended that strict compliance with the primary meaning was an essential requirement of the invention. If yes, the variant is outside the claim.
3. On the other hand, a negative answer to the last question would lead to the conclusion that the patentee was intending the word or phrase to have not a literal but a figurative meaning (the figure being a form of synecdoche (A figure by which a more comprehensive term is used for a less comprehensive or vice versâ; as whole for part or part for whole, genus for species or species for genus, etc.) or metonymy (A figure of speech which consists in substituting for the name of a thing the name of an attribute of it or of something closely related.)) denoting a class of things which include the variant and the literal meaning, the latter being perhaps the most perfect, best-known or striking example of the class.
10. The addressee of the specification in this case seems to me to be a production engineer. He or she is the person who takes the design from the designers and turns it into something which can be made, and designs the equipment, if necessary with assistance from manufacturers of suitable machines.
11. At this point, it is necessary to say a word about the experts. The experts in the present case were Mr Dunning for Pifco and Mr Frazer for Philips. Mr Dunning had a wide knowledge of plastics materials and their applications, but his relevant design experience was somewhat limited and his approach seemed to me to be on the theoretical side.
12. Mr Frazer had designed many plastics products. His one recent foray into heating apparatus appeared to be an electrical facial sauna for Boots designed in about 1985. I thought from the cross-examination that it was going to be suggested that he had copied a Pifco design for a facial sauna, and that his copy was not very good and failed, but that allegation was not, in the end, persisted in. Pifco did attack Mr Frazer, however. They said three things about him. The first was that he was "on side", which means that he knew what the party line was, and was sticking to it. The second is that he avoided questions, and the last that he got things wrong. The only example which I was given of his reluctance to be objective, but stick to the party line, was his evidence under cross-examination to the effect that some systems were extremely well known, but could give no examples. The cross-examination at transcript 487-490 was referred to. I think he did in fact give his answer at page 497, when he said that he was aware that a company called Ford Engineering had used the technique he was describing. This passage in his cross examination was also relied on as an example of his reluctance to answer the question. I think he did answer the question. Finally, it was said that the force diagram in paragraph 23 of his third report was nonsense. It was. It assumes wrongly that the force exerted by the seal on the element can be considered to be inversely proportional to the seal thickness. It should be considered (very approximately) as inversely proportional to the change in seal thickness. He was here answering outside his expertise, and he should not have ventured into the mathematics of the subject. Nonetheless, I will not discount Mr Frazer's evidence on matters within his expertise. I believe that both experts were doing their best to help me come to a conclusion.
13. Finally, I should refer to the evidence of Mr Eagles. Mr Eagles was the development manager of Phasa Developments Limited, who had made the machines on which Philips moulded the base of their kettles. Phasa has consulted with both Pifco and Philips about using their machine to fit planar elements into kettle bases. He has worked in the plastics industry for 37 years. In my judgment, he was precisely the sort of man whom I envisage as part of the team to whom the specification is addressed. He had to explain how the machines which his company had supplied worked. He was criticised by Mr Kitchin QC for being unqualified. The main thrust of this criticism seems to have been that he had never been on a course to learn about the properties of polymers.
4. Q. May I ask you first of all some questions about your background and the background of the PHASA business. You joined PHASA in the mid-1980s?
5. A. PHASA was formed in the mid-1980s as a consequence of something I developed.
6. Q. The particular interest of PHASA is hot air staking? A. Principally, yes.
Q. It was in 1993 and 1994?
A. Yes.
7. Q. In fact, I think as you explain, you were the originators of the hot air staking process, at least in this country?
A. Yes.
8. Q. You make machines to enable that process to be performed?
A. Yes.
9. Q. And so would it be right to say that the particular interest of your company, when it comes to potential customers, is seeing whether or not you can implement the hot air staking process and, even better, sell them a machine to perform it?
A. Yes.
10. Q. I mean absolutely no disrespect to you by these questions. I have to set the scene as best I can. Would I be correct in understanding that you have no formal qualifications in material science?
12. Q. You have no qualifications in the behavior of plastics?
A. No.
13. Q. Do you have any experience of crystalline plastics?
14. A. Only in forming them and general practical work on them.
15. Q. Do you have any qualifications in rheology?
A. No.
16. Q. Have you ever been on a polymer course?
A. No.
17. I am unconcerned at his lack of formal qualifications. It was quite clear that Mr Eagles had a sound practical knowledge of his subject gained over many years. I believe that his expressions of opinion are entitled to respect.
The common general knowledge
14. I have already expressed the view that the addressee of the specification is a production engineer who takes a design from the designers and turns it into something which can be made, designing the equipment to be used, if necessary with assistance from manufacturers of suitable machines. Before I construe the specification through the eyes of such a person, I must examine in more detail the common general knowledge which he or she should possess. In Beloit v Valmet [1997] RPC 489 at 494, Aldous LJ (with whom Hirst LJ and Schiemann LJ agreed) said this:
"It has never been easy to differentiate between common general knowledge and that which is known by some. It has become particularly difficult with the modern ability to circulate and retrieve information. Employees of some companies, with the use of libraries and patent departments, will become aware of information soon after it is published in a whole variety of documents; whereas others, without such advantages, may never do so until that information is accepted generally and put into practice. The notional skilled addressee is the ordinary man who may not have the advantages that some employees of large companies may have. The information in a patent specification is addressed to such a man and must contain sufficient details for him to understand and to apply the invention. It will only lack an inventive step if it is obvious to such a man.
It follows that evidence that a fact is known or event well-known to a witness does not establish that that fact forms part of the common general knowledge. Neither does it follow that it will form part of the common general knowledge if it is recorded in a document. "
18. The Court of Appeal adopted the words of Luxmoore LJ in British Acoustic Films v Nettlefold 53 RPC 221 at 250:
"In my judgment it is not sufficient to prove common general knowledge that a particular disclosure is made in an article, or series of articles, in a scientific journal, no matter how wide the circulation of that journal may be, in the absence of any evidence that the disclosure is accepted generally by those who are engaged in the art to which the disclosure relates. A piece of particular knowledge as disclosed in a scientific paper does not become common general knowledge merely because it is widely read, and still less because it is widely circulated. Such a piece of knowledge only becomes general knowledge when it is generally known and accepted without question by the bulk of those who are engaged in the particular art; in other words, when it becomes part of their common stock of knowledge relating to the art."
19. Aldous LJ said that in order to establish whether something is common general knowledge, the first and most important step is to look at the sources from which the skilled addressee could acquire his information. I would add that although it has to be remembered that a specification may fail to provide sufficient details for the addressee to understand and apply the invention, and so be insufficient and invalid, it is often possible to deduce the attributes which the skilled man must possess from the assumptions which the specification clearly makes about his abilities.
15. In paragraph 39 of his report, Mr Dunning set out a number of facts which he said were bound to be known by the vast majority of persons to whom this patent is addressed. He had reminded himself that the patent is not addressed to kettle manufacturers in particular, but to manufacturers of "heating devices" which might be made of metal. It is of course unrealistic, and wrong, to reduce the common general knowledge of the addressee to matters which all potential addressees (that is production engineers producing metal devices and production engineers producing plastic devices or manufacturers of kettles and manufacturers of other heating devices) have in common. They may have very little in common. Every class of persons interested in the subject matter brings with him his own common general knowledge, which may be different for those interested in metal from what known to those interested in plastic. There were nine particular aspects of the common general knowledge identified by Mr Dunning:
1. That planar elements existed and that it would be beneficial to incorporate them into kettles (metal as well as plastic) for the reasons set out in the patent in suit;
2. That rolled-over collars were used in certain applications. These applications generally involved the joining of two pieces of metal where the parts joined would have similar coefficients of thermal expansion.
3. That important factors in the success of roll-over methods were the stiffness provided by the metal parts and the absence of spring-back and creep in the rolled-over material. Typical examples of such applications known at the time would have been in the manufacture of cans for canned food and drink.
4. That the constituent parts of a kettle could be assembled by the use of screws, snap-fit arrangements and glue.
5. That if the kettle parts were both metal, fixing methods could also include welding, soldering and brazing.
6. The use, in certain applications, of the heat-staking of plastic rivets protruding from one part through a second part to hold that second part in position.
7. The properties of plastics such as polypropylene, including their comparative heat resistances.
8. The various compositions and designs of seals and their properties. Mr Dunning said that it would be normal for a specialist in seals to be consulted by a designer who needed a suitable seal.
9. The use of precompression of rubber seals in certain high vacuum applications.
16. I gathered from Mr Dunning's evidence that it was normal to approach specialist suppliers of materials and machines for advice in respect of such matters as seals (the example referred to in evidence was Dowty Seals) and machinery for manufacture (such as Phasa Developments, Mr Eagles' company). Confronted with the problem of fixing a planar element in a plastic kettle, Mr Dunning accepted that Phasa might well have been approached. Heat-staking, which is one of the techniques in which Phasa was interested and which Mr Dunning considered to be part of the common general knowledge, is important in the present case, and I shall describe it here.
17. Heat-staking is a technique which is well described in a transcript of a talk given by Mr Eagles in 1988 which is Annex 6 to his report. The method uses what are essentially plastic rivets formed integral with one of the components to be joined. The other components are designed so that the rivet passes through them. After assembly, the end of the rivet is heated and turned over using a tool called a stake. Mr Eagles' evidence was that Phasa's contribution to this art had been the use of controlled hot air to heat the plastic followed by the use of a cool stake to achieve the necessary deformation. Mr Kitchin cross-examined Mr Eagles on the basis that in 1992 Phasa knew more about this technique than anyone else, and it seems clear on the evidence before me that this was the case.
18. Mr Eagles' paper points out that the Phasa system has many other capabilities: "Inserts can be fitted into heated holes and the top edge rolled over to improve appearance or retention." By May 1992, Mr Eagles was actively promoting his hot-air system for both rivet-type heat-staking and for the production of " annular roll overs" for retaining seals and glands within plastic housings. So much is clear from the paper prepared for a seminar in Birmingham on 20th May 1992. This provides an extensive survey of potential applications for the hot-air technique. As Mr Eagles acknowledged under cross-examination, there is no suggestion that the roll-over can be used to retain a resilient article, nor that it can form a waterproof joint, but it seems to me that this has nothing to do with the general technique. It also seems to me that these two capabilities are obvious.
19. The patent in suit says nothing about how an upstanding collar can be deformed. It assumes that the skilled man will be able to produce a workable kettle by following the direction at page 8 line 16: "Whilst under compression, heat is applied to the collar 9 so that it can be deformed and turned over by a mandrel or similar apparatus into contact with the annulus 6, as shown in Fig. 3." Rather surprisingly, Pifco contended that deformation by heat-staking was not common general knowledge prior to July 1994. This is contrary to Mr Dunning's evidence in chief so far as rivets are concerned, although there is some suggestion in his cross-examination that he was seeking to modify and restrict this admission: see transcript 163 lines 6 to 16. Certainly hot-air heat-staking was in use in the electronics and automotive industries and the communications industry, as he himself admitted, and he was aware of it as one of the vast range of assembly techniques for plastic devices. Mr Dunning's evidence in paragraph 118 of his statement was that "limited use of rolled over collar concept had been made but certainly not in circumstances where watertight seals, and a tolerance to a wide range of temperatures, were required".
20. Pifco say that Mr Eagles had certainly failed to acquaint the industry generally with the hot-air heat-staking technique. It is pointed out that on Mr Eagles' evidence 75% of Phasa's business was with rivet heads. Of course, on its own this consideration is neutral. An infrequently used technique can still be common general knowledge. It is said that rolling over onto compressible surfaces is only mentioned in Phasa's literature after mid-1994, but this is irrelevant if the technique is of general application.
21. Mr Eagles did, however, acquaint both Pifco and Philips with the technique before the priority date, and the invention of the patent in suit is in fact based upon a development which Pifco made with heat staking, which they never followed up. The production Pifco kettle was secured with screws, because Pifco were not confident in heat-staking as a technique for retaining planar elements in kettles. I am therefore confronted with a rather unusual situation. The patent is no doubt sufficient, because if the kettle is made of metal a standard technique for securing is to roll a upstanding collar over the thing to be secured: every tin uses it. But in relation to plastic, it is not suggested that there is any viable method other than hot-air heat staking to make the roll over secure the planar element, its seal and securing ring. Hot air staking is used because it heats the plastic sufficiently to ensure that memory effects are minimised. The patent, which describes only a plastic kettle, assumes that the addressee will be able to form the roll over. The patentee now says that the only technique known to be capable of forming the roll over is not common general knowledge. I believe that the patentee's assertion, articulated in the patent, that the skilled man will be able to form the roll over by following the directions which I have quoted is something which I should take into account when deciding whether hot-air heat staking is part of the common general knowledge.
22. I have come to the conclusion that I ought not to hold that hot-air heat staking techniques were part of the common general knowledge in the art. This finding entails the undesirable consequence that the description of the preferred embodiment of the patent in suit is or may be insufficient. I am very conscious that information said to be common general knowledge must satisfy the stringent requirements set out in Beloit, and in my judgment those requirements are not satisfied in respect of hot-air heat-staking. I must construe the specification through the eyes of an addressee who does not understand how to effect the roll-over in plastic material. The reader of the specification would know that it would be desirable to achieve roll-over of a plastic collar, if it can be managed.
- I should just add that there was some suggestion that when a skilled man was setting about retaining a resilient seal using the roll-over technique, it would not have been second nature to him to preload the seal to compress it prior to carrying out the roll-over. I think this is a very strange idea. If a positive force cannot be applied by use of the fastening means itself, as it can in the case of a screw or a bolt, it seems to me to be self-evident that the necessary compression to achieve a physical seal must be achieved in some other way before steps are taken to retain the seal in position.
The alleged infringements
24. In general terms, the Philips kettle consists of a cylindrical plastic body, in the base of which there is a circumferential flange and a cylindrical collar. This flange accommodates a silicone rubber seal which is generally C-shaped and fits round the edge of the element. On the outer side of the seal, a nylon ring is placed. The collar is deformed so as to bear upon the nylon ring, and so hold the seal and element against the flange. This is a photograph of a section through the base part of the kettle, which is the only part which matters for this purpose.
25. Philips make the allegedly infringing kettles on two machines. These are called the Phasa machines. They were supplied to Philips by Mr Eagles' company. The description of their operation is set out in the Experts' Agreed Description of the Philips' Kettle Deforming process. Each stage of the process described has two alternatives, described as being "With Preload On" and "With Preload Off". These alternatives refer to the way in which the two Phasa machines operate. The outline of operations is the same in the case of both. The operator places the nylon ring, which is the "securing means" of the claim, on the inner of two concentric pistons. The inner piston carries the securing ring, and the outer is shaped so as to turn the collar of the kettle over to trap the ring. The pistons move independently.
26. The body of the kettle is placed flange upwards over a vacuum arrangement and the element is placed against the flange. The vacuum is then applied to hold the element against the flange. The upside-down kettle body, with the element held in position by the vacuum, is then placed inside the Phasa machine. The collar is heated by a blast of hot air from a manifold which descends to surround it. The securing ring is placed against the ouside of the seal. The softened collar is turned over by the outer of the two pistons to trap the ring against the seal. The collar is then allowed to cool in contact with the outer piston. At the end of the cooling period, the piston arrangement is raised, the vacuum released and the assembly removed from the machine. The difference between the machines (both of which are alleged to infringe) lies in the manner in which the ring is placed against the seal.
27. With preload on
20. In the machine which operates with preload on, the inner piston is pushed away from the outer, so that the ring is proud of the forming piston. Immediately after the heat is applied and before the forming stage is complete, the relative positions of the components is shown in Figure 1.
Figure 1
21. In this diagram, I have indicated the preload by the heavy arrow.
28. With preload off
22. When no preload is applied, the inner piston carrying the nylon securing ring is not forced down in the direction I have shown with the heavy arrow. It is held against its upper stop by a spring, which is not shown in the diagram. This means that at the same time in the cycle as Figure 1, the position is shown in Figure 2:
Figure 2
23. The force on the inner piston is again shown by the heavy arrow.
29. When the forming mandrel and the inner piston descend towards the heated collar, the sequence of events depends on whether the preload is on or off. When the preload is on, the nylon securing ring comes into contact with the C-shaped seal rather before the forming mandrel meets the undeformed collar. When the preload is off, both operations happen simultaneously, so that the plastic has been deformed into the space formed between the ring and the mandrel before the ring comes into contact with the seal. These are best seen side by side.
Figure 3
24. The evidence is that in the case where preload is off, the volume of the space into which the material of the collar is displaced is rather less than the volume of the material itself, and so it forces its way through the available spaces to form "flash". This flash is observed to flow down the outer wall of the collar and up the gap between the red forming mandrel and the green inner piston.
Infringement - general
30. In the context of infringement, a number of issues of construction arise. There is no doubt that the pre-characterising features of the claim (1, 2, 3 and 4) are present in the method of construction of the kettle which I have described above. When this method is carried out, the step of putting the C-section seal on the edge of the element, and putting the element in the base of the kettle to rest against the flange satisfies features 5, 6 and 7.
31. The first question which arises is what the claim means when it talks in feature 8 about the securing means being positioned on the element. The claim is unspecific as to the nature of the securing means: it is inferentially defined by its function. As to its position, it would be surprising if the principal claim of the patent failed to cover one of the alternative embodiments. The specification says (page 7 lines 22 to 27) that in the context of Figures 2 and 3 the seal can be a C-section gasket, and in that case the part which wraps round the element is "covered by the annulus 6", which is the securing means. I cannot give a sensible meaning to this unless the annulus sits on the part of the seal closest to it. It seems to me that the words "on the element" in their context mean that the securing means is positioned on the element whether or not there is some intervening component, provided that the securing means perform its function, viz to retain the element in position as feature 11 of the claim requires.
32. The second question which arises is as to the sequence of operations for which the claim calls in features 9, 10 and 11. Feature 9 calls for "retaining the element and the securing means in position with the element in contact with the sealing means whilst compressing the sealing means by a predetermined amount." On the face of it, the words "in position" refer to the position in which the element and securing means were placed in feature 8. Thus, the seal, element and securing means are held in their correct relative positions as the seal is compressed.
33. The meaning of the phrase "predetermined amount" is also a matter of controversy. Before considering it, I think it is necessary to consider the purpose of the compression, which is plainly to create a seal. Any resilient sealing material which is not adhesive needs to be compressed, since it relies upon the force of compression to resist the pressure of the liquid seeking to penetrate the seal. If it is adhesive, additional compressive force may not be necessary, since the pressure of the liquid seeking to penetrate the seal must overcome the adhesive forces between the material and the substrate. Thus, the sealing material of the claim is impliedly resilient, and is compressed as a distinct step before the deforming step of feature 10. The amount by which it is compressed is (at least) the amount by which it is desired to compress the seal in the finished article.
34. Philips submit that the compression of feature 9 of the claim is required by the claim to be the only compression which the seal undergoes. Thus, they say, if the deforming step itself further compresses the seal, the degree of compression applied during the compression step is not the degree of compression required in the completed article, and is not the predetermined amount required in the completed article. I have no hesitation in rejecting this construction. Of course the compression applied is that required to produce the seal. But I believe that it is clear from the specification that the whole of the requisite compression is not required to be applied at a single stage. In describing the preferred embodiment, the specification says this at page 8:
25. Once the assembly as shown in Fig. 2 has been made, the seal 7, the element 5 and the annulus 6 are held in position whilst the seal is compressed by a predetermined amount, which is preferably between 30% and 40% of its original diameter. The compression is preferably carried out by applying a reduced pressure to the interior of the vessel 1 ... Alternatively, the compression can be effected by the application of external pressure to the annulus 6.
26. Whilst under compression, heat is applied to the collar 9 so that it can be deformed and turned over by a mandrel or similar apparatus into contact with the annulus 6 ... The turned over portion 15 of the collar 9 retains the element 5 in position and the seal 7 under compression via the annulus 6 to ensure a water- and air-tight joint.
27. It seems to me that in the process as described the turned-over portion of the collar is bound to exert pressure on the annulus 6 unless exceptional steps are taken to prevent it doing so. Indeed the result of the turning over is intended to be a component which retains the element and seal under compression, and it seems extraordinary to exclude additional compression in the turnover stage if the whole purpose of the turnover is to retain those components under compression. I believe that the reading which Philips seek to give the claim is altogether too literal. However, it is suggested that Mr Dunning disagrees with the view I take. At page 217 of his cross-examination, he gave the following evidence.
28. Q. Can we go back to your witness statement and look at paragraph 27. This is your first expert report. In paragraph 26, if I can ask you to look at that first, you explain that on a further reading of the patent there are certain additional benefits. You refer to advantages which required three essential elements to be present. The first element which you referred to was that, once the seal and element are correctly positioned, the seal is compressed by a predetermined amount. Can I now ask you, with that background, to look at paragraph 27, where you explain why that first element is important. What you say is that it is important more directly because by compressing the seal before the kettle body is deformed it is not necessary to try to compress the seal utilising the same forces as those carrying out the deformation of the kettle body. It would be very difficult to make a process which deformed the kettle body and compressed the seal simultaneously work satisfactorily or repeatedly. That was the view that you formed on your further reading of the patent concerning the process.
29. A. Yes, I thought that, if the force was applied through the material which was being deformed, then this would be a very difficult process to control.
30. Q. And certainly not something that would be obvious to do having read the patent.
31. A. I am sorry, what would not be obvious?
32. Q. To try to compress the seal utilising the same forces as those carrying [out] the deformation of the kettle body is not something hat would occur to you as an obvious step having read the patent.
34. This cross-examination is directed to the question whether a variant consisting of applying the whole of the compressive force by means of the turning over of the collar would have an effect on the working of the invention, and that this fact would be obvious to the skilled man. It does not deal with whether the skilled man would appreciate that an additional compressive force over and above that exercised by the vacuum would have no effect on the way the invention worked. In any event, I am quite sure that there is no difference in the way the invention works if there is additional compressive force applied at the turnover stage. There is certainly nothing in the specification to exclude such a possibility and the result, which is an element retained by the securing means with the seal under pressure, is precisely the same, as I believe any skilled man would appreciate.
35. Mr Carr argued on behalf of Philips that the compression achieved by carrying out the steps of feature 9 of the claim ("compressing the sealing means by a predetermined amount") had to be the same amount of compression as that retained by the completed structure in feature 11. Mr Kitchin agreed with him. I do not believe this is so, and I am particularly influenced by considering what would happen if, following the directions of the patent, a C-shaped seal positioned around the perimeter of the element was used rather than an O-ring as shown (page 7 lines 22-23) and a vacuum used for the purposes of compression (page 8 lines 5-8). Clearly, until the sealing annulus 6 was placed in position, the arm of the seal on the outside of the element would be uncompressed. If the annulus merely touched the seal, release of the vacuum would permit the compressed seal on the wet side of the element to expand until the compressive forces on both sides of the element balanced and the compressive forces would be reduced. If on the other hand a sufficient further compressive force were applied to the dry side of the seal by turning the collar over, both sides of the seal would be further compressed, but on cooling and release of the vacuum they would equilibrate to a point where the compression on the wet side of the seal would not be far removed from the compression originally produced by the vacuum alone.
36. A second possibility contemplated by the specification is the use of a C-shaped seal in contact with the annulus (page 7 line 25-27). In this embodiment, the compressive forces may be transmitted via the annulus (page 8 lines 8-10). The compressive forces would not be reduced at all after the collar had been turned over and the externally applied force released.
37. I believe that the specification clearly contemplates both the possibilities that I have described. Thus, in my judgment the compression of feature 11 does not have to be the same as the compression referred to in feature 9. Neither party before me was willing to take this view: Pifco because it broadened the claim undesirably having regard to the state of the art, and Philips because it would probably result in a finding of infringement. For the reasons which I have given I believe that both of them were construing these features in an unduly narrow sense.
Infringement - the effect of the vacuum
38. When the vacuum in the Phasa machine is applied to the element and its seal, it compresses the "wet side" of the seal against the flange in the body of the kettle. The dry arm of the seal, against which the securing ring will be placed, is not compressed. There was a dispute between the experts as to how the compression on the wet side was accommodated, since the seal material is substantially incompressible in the sense that it does not change volume under compression. As I understand the evidence, compression of the wet side of the seal displaces material, first into a bulge on the wet side and second round the corner of the element, resulting in a slight increase in length (though not of thickness) on the dry side. Immediately before the securing ring is placed against the dry side of the seal, one side of the seal is under compression, but the other is not under compression at all.
Infringement - preload on
39. When the preload is on, the securing ring moves into contact with the dry side of the seal before the forming mandrel descends to shape the softened collar. It seems to be accepted that some additional compression of the seal is achieved by the descent of the securing ring on its piston. The descent of the forming mandrel turns the collar over. There was a great deal of discussion and evidence as to whether the turning over of the collar to contact the ring substantially affected the compression of the seal. Until the securing ring moves into contact with it, the dry side of the seal is substantially uncompressed. Mr Eagles was satisfied that a substantial compressive force was applied as a result of the action of the forming mandrel. I would anyway be inclined to accept his opinion, and it was supported by the experiment conducted by Philips, which showed that the force applied by the forming mandrel to the ring was enough to form a satisfactory seal without the use of the vacuum at all. For the reasons which I have given in considering the construction of this part of the claim, I do not consider that this changes the position on infringement.
40. The imposition of the vacuum satisfies feature 9 of the claim. The fact that the ultimate compression may be or is different from that resulting from the imposition of the vacuum is irrelevant and the requirements of feature 11 are satisfied also. It follows that each of features 9, 10 and 11 of the claim are present when the Phasa machine is operated with the preload on. The operation of the Phasa machine with the preload on infringes the claim.
Infringement - preload off
41. The necessary compression to satisfy feature 9 of the claim is achieved by the imposition of the vacuum. Although the upper part of the seal is compressed only when the material of the collar is turned over to contact the ring, I believe that feature 11 of the claim is also present.
Infringement - conclusion
42. In the result, the Phasa machine infringes both when operated with preload on and when operated with preload off.
Validity
43. The validity of the patent is attacked on the grounds of lack of novelty and obviousness. The only matter alleged to anticipate the claim is the prior sale by Boots of a baby's bottle-warmer called the Avent. A sample of the warmer in question, which is sectioned and "potted" in acrylic to show the construction, is P4. Obviousness is also alleged over two documents, UK specification 602,563 (Williams) and European patent 0 574 310 (Sarrazin).
44. Claim 1 is a method claim. The law of anticipation is that a prior use will invalidate only if it is enabling, that is, if it gives the skilled man clear and unambigous directions to do something which, if done after the date of the patent, would infringe (see General Tire v Firestone [1972] RPC 457 at page 485 and, for the proposition that the prior use must be enabling, see Merrell Dow v H N Norton [1996] RPC 76 at page 89). The question is what the Avent bottle warmer communicates to the skilled man, and to answer it I must put myself in the same position as the skilled man, with his common general knowledge which I have discussed above.
The Avent bottle warmer
45. The Avent bottle warmer is shown in Figure 4. The element is cast alloy and occupies an aperture which covers a substantial part of the well above which the bottle stands. The element has a peripheral upstand, which carries a C-shaped seal. The seal is jammed in a generally elliptical recess, and it is retained in position by a nylon spacer, which is equipped with 3 so-called fir trees or Christmas trees which are themselves jam fits in holes designed to receive them. These fir trees are easy to push in, but difficult to pull out. Three integral rivets extend generally downwards from the base of the well, passing through the spacer and the outer base cover. These rivets are heat-staked to hold the sandwich of spacer and element so that the edges of the element are jammed into their recess.
46. The questions which arise in relation to the Avent warmer are:
(i) Is the element planar and is it integrated in the body of the vessel?
(ii) Does it disclose how it was made? and, if so
(iii) Was there a predetermined compression?
(iv) Is the nylon spacer a "securing means"?
(v) When the rivets were staked, was a portion of the body of the vessel in a region around the aperture deformed in a direction inwardly of the aperture.
Figure 4
47. Each of these questions involves a question of construction. Taking them in order, "planar" means generally flat. I think that the term imports no more than that the element is the sort which is capable of filling an aperture, that is, generally plate-like. Certainly it includes finned plates, as Mr Kitchin accepted. Mr Kitchin said that the Avent element is not planar, but bowl-shaped. Mr Dunning appears to have accepted that the Avent element was planar, saying that the element is a planar element with a flange around its periphery. This evidence is not admissible absent a suggestion that planar had some special meaning in the art, but I think that this is the right way of looking at it.
48. The word "integrated" cannot be used in the specification in a narrow sense, since the materials said to be integrated are dissimilar. That means that a looser, structural sense must be intended, and I believe that the term means no more than that the element forms one of the walls of the vessel. So the Avent device has this feature.
49. Mr Dunning sets out the most likely order of construction of the Avent based on the common general knowledge and on an inspection of the device in paragraph 14 of his second supplementary report. This seems to be common sense, and I have no doubt that this is what the Avent discloses. The essential order is thus that called for by the claim.
50. The meaning of the term "predetermined compression" is, as a matter of ordinary English, a compression decided upon before it is applied. For the reasons which I have already given, I do not accept that it is the degree of compression present in the product. Thus, if I have a criterion for compression (be it force to be applied, or thickness of the seal resulting from the compression) according to which I compress the seal, I am applying a predetermined compression. I am bound to say that this seems to me to be elementary. I think that it is defying common sense to suggest that in modern mass production it is possible that the degree to which the nylon spacer is pushed against the element and seals in the Avent warmer is a matter of chance. In any event, paragraphs 14.3, 14.4 and 14.5 of Mr Dunning's second supplementary report say that the article which is pushed is the spacer. This applies a predetermined compression to the seal.
51. Again the "securing means" of features 8, 10 and 11 of the claim have to be construed as a matter of ordinary English. The spacer obstructs the tendency of the element to detach itself from the body of the heater: it seems to me it is plainly a securing means, the more so because it carries the fir trees which help in this function.
52. The real question is in relation to the rivets. The relevant features of the claim are 10 and 11. Given that the common general knowledge of the skilled man does not extend to a method of turning a collar of plastic material over using hot-air heat staking but that heat staked rivets are part of the common general knowledge, what methods of deformation are contemplated by the claim? I must start with the purpose of these features of the claim. The purpose of the deformation is to permit the use of a planar element while mitigating the disadvantage of having the element in direct contact with the body of the kettle. This is what the invention is concerned with. Apart from the fact that the fixing of the element is to be accomplished by deformation of a part of the body itself, the patentee devotes no time to setting out any matter relating to this deformation or the portions of the body to be deformed. So far as the specification is concerned, it is enough if a satisfactory seal is obtained. Viewed as a whole, I believe that on a proper construction features 10 and 11 of the claim contemplates deformation only of some part of the heating apparatus which can be regarded as its body. Obviously a collar which is merely an extension of a generally cylindrical body suffices, as does a collar which surrounds an aperture substantially smaller in radius than the radius of the base of the heating apparatus (there is no limitation to an element of generally similar radius to that of the base). Given that the claim must contemplate turning over a collar surrounding a comparatively small aperture formed in some wall of the heating apparatus, I can see no reason for saying that the collar must be continuous, and the claim quite clearly contemplates discontinuity. I believe that it follows that a number of short sections of collar are within the contemplation of the claim.
53. I cannot find any basis in the words of the claim or in the specification for including short sections of collar integral with the body yet excluding rivet-like pieces of plastic integral with the body. Rivets will of course be heat-staked to spread in all directions, but all the claim requires is turnover inwardly of the aperture. It does not exclude turnover in other directions as well.
54. In my judgment, claims 2 and 3 tend to confirm my view that the scope of features 10 and 11 of the claim are comparatively wide. Claim 2 suggests that claim 1 contemplates deformation of a portion of the body of the vessel which is not around the periphery of the aperture, but may be elsewhere. Claim 3 expressly identifies a collar as the deformable portion. I am conscious that this approach to construction must be used with care, since it may justifiably be criticised as being the kind of meticulous verbal analysis in which lawyers are too often tempted by their training to indulge. But on a purposive construction, I believe that the very general words of features 10 and 11 cover deformation of cylindrical rivets so that their deformed heads come into contact with the securing means.
55. Finally, do the heat-staked rivets retain the securing means? On the evidence, it is quite clear that they do. The fir-tree portions do as well, but they can be pulled out. The turned over rivets are much more resistant to forces tending to separate the element from the body of the heating apparatus. It cannot matter that they also hold the outer cover of the warmer in position. It follows that in my judgment the sale of the Avent bottle warmer gave to the relevant skilled person clear and unambiguous description of a method of making such an article and claim 1 is anticipated. Claim 10, the corresponding apparatus claim, is equally anticipated.
Williams
56. Williams is not alleged to be an anticipation, but is said to render the invention obvious. Williams discloses a metal kettle with a metal base which does not include an element. There is on the evidence no resilient seal, the seal between the kettle and its base being accomplished by use of optional "jointing or filling cement". There being no evidence that these words bore any special technical meaning, these words do not disclose the use of a flexible or compressible seal.
57. It is convenient to adopt the structured approach to obviousness described by Oliver LJ in Windsurfing International v Tabur Marine [1985] RPC 59 at 73:
"There are, we think, four steps which require to be taken in answering the jury question. The first is to identify the inventive concept embodied in the patent in suit. Thereafter, the court has to assume the mantle of the normally skilled but unimaginative addressee in the art at the priority date and to impute to him what was, at that date, common general knowledge in the art in question. The third step is to identify what, if any, differences exist between the matter cited as being "known or used" and the alleged invention. Finally, the court has to ask itself whether, viewed without any knowledge of the alleged invention, those differences constitute steps which would have been obvious to the skilled man or whether they require any degree of invention."
58. The inventive concept of the patent in suit is what is claimed in claim 1, correctly construed. I believe that an attempt to gloss the actual words of the claim can lead to error. Williams lacks an integral element, or a compressible seal. In so far as it describes a method of construction, it seems to me that the differences amount to the whole of the inventive concept, and that Williams adds nothing to a case of obviousness based on the common general knowledge alone which I shall consider below.
Sarrazin
59. Sarrazin is a patent which is concerned with a particular type of planar element. However, it exemplifies the use of the element in a plastic bodied kettle of generally conventional shape. The edge of the element is enclosed in a C-shape seal, and is seated against a flange in the body of the kettle. The assembly of seal and element is retained in position by a click-fit arrangement. When the base of the kettle is clicked into position, a cylindrical portion of the base presses against the seal, holding it in compression and so sealing the base of the kettle. (If there is no compression the latches will be loose.) It thus discloses in combination (a) a C-shaped seal (b) a planar element (c) compression of the seal. It lacks a distinct compression step in manufacture (this is irrelevant to claim 10) a separate securing means and a roll-over of a portion of the body onto the securing means.
60. In my judgment, the position in respect of Sarrazin is the same as that in respect of Williams. Essentially all the inventive concept is missing from the device, and the argument reduces to a suggestion that the invention is obvious in the light of the common general knowledge. It is simply not possible without a great deal of hindsight to hypothesize an obvious development leading to the alleged invention.
Common general knowledge
61. I have held that heat staking of collars was not common general knowledge at the date of the patent, but that heat staking of rivets was. The question is whether it was obvious to the skilled person to make something falling within the claim confronted merely with the requirement to incorporate a planar element in a plastic body.
62. I start with the proposition that it was obvious to surround the element with a seal and lodge it up against a flange in the body of the kettle. In the context of Sarrazin, this was described by Mr Dunning as the natural way to put planar elements in vessels. It was suggested that it required insight to appreciate that this method accommodates different coefficients of expansion in kettle body and element, but it seems to me that it is both obvious that such differences must be accommodated and that the use of a flexible seal is an obvious way of doing so. Then the question is how to hold the element and its seal in the recess without destroying the capacity to accommodate differential rates of thermal expansion. To help them reach a design, Philips went to an outside consultancy, IDC, who produced a large number of designs. This included one rather like Sarrazin (Design E) and I believe 24 others, none of which uses heat-staking of any description but which do use screws, hot plate welding, and other securing techniques. These designs confirm Mr Dunning's evidence that the natural way to insert the element is to put in a recess with a seal but they offer scant support for the suggestion that heat-staking was common general knowledge. When it was adopted, there was a considerable delay before it was decided to employ the nylon retaining ring.
63. Mr Frazer suggested a series of obvious alternative techniques for fastening the element in position. To some extent, these coincide with IDC's proposals. There are others as well, and he included heat-staked integral rivets (paragraphs 36 and 37). Mr Dunning said that he would take each of Mr Frazer's proposals and modify them. He did not suggest that they were anything other than the result of using ordinary design skills. For the reasons I have given in respect of Avent, I consider that manufacture of the paragraph 36 design would fall within the claim, which is accordingly invalid. Mr Dunning accepted that the heat-staked rivets were an obvious and common sense option. He drew the line at paragraph 38 of Mr Frazer's report, which mentions a design in which there is a "swage over" onto a securing member (the cover) which bears on the seal and serves to hold the seal against the flange. It turned out that he did not accept that this design was obvious in plastic, but he accepted it to be a commonsense option in metal. There was an attempt, which failed, to re-examine him out of this conclusion. Manufacture of this design would fall within the claim provided that the seal is pre-compressed by clamping the cover so that the edges of the cover come into contact with the body. This is the obvious way of making such a metal kettle. It was obvious in 1994, and the claim is invalid for this reason also.
64. As is often the case, there were a large number of alternatives all of which were alleged to be equally obvious. Pifco's case occasionally suggested that from a large field of obvious alternatives the patent selected an advantageous combination. But there is no real evidence that it was advantageous. It avoids the simplicity of screws, but that means that the element cannot be replaced when it fails and the kettle has to be thrown away. That may be a commercial advantage, but it is not a technical one. Confronted with the choice of using the patented method and screws, Pifco itself opted for screws. There was no evidence of any technical advantage, and no evidence of any particular advantage in production.
65. It has never been suggested that the factors affecting validity may be different in the case of a plastic kettle as opposed to one made of metal. I conclude that claim 1 is incurably invalid, and claim 10 goes with it.
Claim 4
66. Claim 4 is alleged to be independently valid. It claims the use of a vacuum to apply a compression to the seal but this is not the predetermined compression of feature 9, which is claimed by claim 5 which is not alleged to be independently valid. So claim 4 includes the use of a vacuum insufficient to produce the necessary compression of claim 1, but which nonetheless produces some compression. It was Mr Dunning's evidence that the use of vacuum to hold articles together in the course of manufacture was a common industrial practice. I cannot accept that claim 4 which plainly covers such a use for holding the element in the kettle (a very obvious product in which to use some vacuum) can be said not to cover such techniques, and it is accordingly invalid.
Conclusions
67. In the result, claims 1, 4 and 10 of the patent are invalid. I have come to no finding on claim 16 but it is manifestly not infringed. Claims 1, 4 and 10 would have been infringed had the patent been valid.
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