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	England and Wales High Court (Patents Court) Decisions
You are here: BAILII >> Databases >> England and Wales High Court (Patents Court) Decisions >> LB Europe Ltd. (t/a Dupont Liquid Packaging Systems) v Smurfit Bag In Box SA & Anor [2007] EWHC 510 (Pat) (15 March 2007) URL: http://www.bailii.org/ew/cases/EWHC/Patents/2007/510.html Cite as: [2007] EWHC 510 (Pat)

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IN THE HIGH COURT OF JUSTICE
CHANCERY DIVISION
PATENTS COURT

		Royal Courts of Justice Strand, London, WC2A 2LL
		15 March 2007

Mr Roger Wyand QC:

Introduction

1. This action was commenced by the Claimant against the First Defendant on the 5^th September 2006 seeking an injunction to restrain unjustifiable threats of patent infringement, a declaration of non-infringement and revocation of European Patent (UK) No 432,070. The Defendant responded by defending the action and counterclaiming by way of a Part 20 claim alleging infringement of the patent. On 16^th November 2006 Mr Justice Kitchin gave directions at a case management conference that the infringement and validity issues be heard separately from the threats issues. He directed that the trial of the infringement and validity issues should take place on the first available date not before 5 February 2007 with an estimate of 2 days with ½ day pre-reading. He also gave the Claimant permission to add the Second Defendant to the proceedings. The trial of the infringement and validity issues came on for hearing before me on 6 February 2007 and lasted 1 ½ days.
2. European Patent (UK) No 432,070 ("the Patent") relates to "the sphere of the distribution of liquids contained in small rigid, semi-rigid or flexible containers, in particular of alcohol-containing beverages subjected to taxing and concerns a tamperproof tap equipped with a taxing device".
3. The Claimant and the First Defendant make and sell flexible liquid packages containing tap units, comprising the tap and the plug into which it is fitted, to leading packers of bag in box wine. In addition, the Second Defendant sells the tap units separately.
4. The Claimant's tap units are sold under the Liqui-Sure trade mark. In October 2004 the Claimant says that it supplied an example of its Liqui-Sure product to the Defendants. In late 2005, the Claimant believed that the Defendants were putting off the Claimant's customers. In September 2006 the Claimant commenced the present proceedings.
5. The issues before me are infringement and validity of the Patent. The grounds of invalidity alleged are that the Patent is obvious having regard to two French Patent Applications, Nos 2 623 268 and 2 619 612, and common general knowledge.
6. The tap units in question are generally used for storing and selling liquids in a flexible bag housed in a cardboard box. These are known as Bag-in-Box. The major market for this is wine and this was first introduced by the Australian wine producers in the early 1970s. The bag is made from an aluminium molecular deposit foil. Since these are disposable products the tap was required to be low cost but had to be as leak tight as possible. The taxation authorities, in particular in France, required that the product should be capable of being sealed with a stamp or licence indicating that tax had been paid. To avoid fraud, this had to be "tamper evident". The Patent set out to solve the problem of a low cost tap that operated satisfactorily but was also capable of accepting a tax stamp and could not be removed from the bag/box.

The Patent

7. I set out below claim 1 divided conveniently into its integers as presented by the Defendants:

Unit comprising a tap, with a plug of a container, essentially consisting of

a) a body for installation in the plug of the container and for distribution of the liquid

b) a piston for release of the liquid

c) which is loaded by a spring

d) the piston acting on an elastic sealing membrane integral with the body

e) which on the one hand is provided with a tap proper

f) having a lower portion for the flow of the liquid

g) and an upper portion integral with the lower portion

h) and forming a guide for the piston and for the spring loading the piston

i) and, on the other hand, comprises an engagement means for fixation in the plug of the container characterised in that it is provided with

j) a tearable taxing device rendering the tap tamperproof

k) and comprising a ring forming a stop between the upper portion of the piston and the lower rim of the upper portion of the tap

l) and in that the engagement means for fixation in the plug of the container comprises a wide groove in the vicinity of the end

m) cooperating by catching with an annular projection of the plug, this projection having a clearance towards the exterior of said plug

n) and a shoulder at an acute angle towards the interior thereof

o) said shoulder being at a distance from the external edge of the plug

p) corresponding to the interval between the external edge of the groove and an edge for application of the body.



8. The claims are in the standard "characterising" form, setting out the features that are acknowledged to be part of the prior art in the pre-characterising clause and the features that are relied on to give inventiveness in the post-characterising clause. In claim 1 there are two post-characterising features, namely, (1) the tearable taxing device (j) and (k) and (2) the engagement means for fixation in the plug (l) to (p). These two features are important in that, together, they make the whole tap and plug unit tamperproof. The tearable taxing device makes it impossible to dispense the liquid without removing the taxing device and thus making it obvious that this has happened. On the other hand, it is no use having the tearable taxing device if it is possible simply to remove the tap unit and replace it with a fresh one with the tearable taxing device intact.
9. However, it is apparent that the two features do not combine in an unexpected manner. Thus, if each of the two features were to be found obvious then there would be nothing inventive in combining the two in one device. See Sabaf v MFI [2005] RPC 10. Accordingly, the Claimant's attack is correctly addressed to the two features separately and not to the combination.

The Prior Art

10. The prior art relied on consists of the two French patent applications and a prior art product, the Waddington and Duval tap, which is accepted to be part of the common general knowledge. M. Alain Dufrene is named as an inventor on both of the French patent applications.
11. M. Dufrene is the author of an expert's report prepared on behalf of the Defendants and he appeared before me to give evidence relating to the validity of the Patent and to the issue of infringement. The Claimant put in an expert's report from a Mr Brian Gough and a witness statement from Mr Stewart Graves who is the managing director of the Claimant company. Mr Graves gave evidence as to the common general knowledge at the priority date of the Patent, 4^th December 1989, and as to some specific dealings the Claimant had with Waddington and Duval and their tap.
12. There is no dispute between the parties as to the nature of the skilled addressee of the Patent. He or she will be a mechanical engineer with experience of design in plastics and with some knowledge of the practical requirements for bottle in the bag products, particularly wine or other alcoholic drinks. Of course this may be more than one person working together as a team.
13. French patent application No 2 623 268 discloses a tap unit with a horizontal cylinder portion with an outlet hole in the bottom of the cylinder which projects outside the body of the container. To escape, the liquid must enter the cylinder and then exit through this outlet hole. In the closed position the cylinder is filled by a finger shaped piece of elastic material. This blocks both the entry to the cylinder and the outlet hole. There is a piston which is narrower than the internal bore of the cylinder which projects out of the external end of the cylinder. When this piston is pushed further in to the cylinder it stretches the elastic material and as it stretches the elastic material narrows so that it no longer blocks the entrance to the cylinder and it lifts off the outlet hole. This allows the liquid to flow out of the container. If the piston is released the elastic material pushes the piston back to its starting position and returns to its original shape, once again blocking the entrance to the cylinder and the outlet hole. A detachable skirting prevents the piston being pushed in until the skirting has been removed.



14. French patent application No 2 619 612 similarly discloses a tap unit with a horizontal cylinder portion with an outlet hole in the bottom of the cylinder which projects outside the body of the container. A piston is slidably inserted into the cylinder. At the end of the piston closest to the container a conical valve is attached. In the closed position this valve blocks the entrance to the cylinder. Behind the valve there are radial holes in the piston. There is a hole in the bottom side of the piston which is not aligned with the outlet hole in the cylinder when it is in the closed position. When the piston is pushed in, the valve opens and allows the liquid to flow into the cylinder. Pushing the piston in also aligns the hole in the bottom of the piston with the outlet hole in the cylinder and the liquid can then flow from the container into the piston and out of the outlet hole. The piston is loaded in the closed position by an elastomeric ring which bears on the outer end of the cylinder and the inner end of a cap on the end of the piston which extends out beyond the end of the cylinder. This deforms resiliently to allow the piston to be pushed in and when the piston is released it causes the piston to spring back into the closed position. There is a detachable ring over the elastomeric ring which blocks movement of the piston and must be removed before the piston can be pushed in.



15. Neither of the French patent applications describes or illustrates how the tap unit is to be fixed in the plug of the container. They both show a cross-section view of the part that is to be inserted into the plug but do not show the cross-section of the plug or how it co-operates with the tap unit.
16. The Waddington and Duval tap has a vertical cylindrical tap body with a vertical piston. At the bottom end of the piston there is a conical valve that closes the bottom end of the cylinder. When the piston is pushed down the conical valve moves down and opens the hole at the bottom of the cylinder. The top end of the piston is attached to an elastomeric dome shaped piece. This dome shaped piece or button is attached to the inside of the tap body near its top. The dome shaped piece loads the piston with an upward force keeping the valve closed. Pressure on the top of the piston or button deforms the dome shaped material resiliently allowing the piston to move down to open the valve. When the piston is released it will spring back into the closed position due to the force exerted by the dome shaped material. There is no ring blocking the movement of the piston. It could be fitted with a removable cap which prevented the button being depressed.



17. The Waddington and Duval tap has a horizontal cylindrical portion which is inserted into the plug in the container. This portion has a profile which appears to be the same as is shown in the French patent applications. It is formed with four sealing ridges, the innermost of which is tapered down to the end of the cylinder making it easier to locate it into the plug. The plug is made from a softer plastic than the tap. It has a smooth shaped interior surface. Its softness allows it to deform slightly to provide a good seal around the sealing ridges on the tap unit when it is pushed in. There is a dispute as to the precise detail of the shape of the inner end of the plug.
18. At the priority date of the Patent the Waddington and Duval tap had about 95% of the market in Europe.

The Evidence

19. I heard evidence from Mr Gough, the Claimant's expert, Mr Graves, the Claimant's managing director and M. Dufrene, the Defendants' expert. I found all of the witnesses straightforward and helpful. However, to a large extent this case turns on construction of the claim of the Patent and the terms to be construed are ordinary words in common usage and no special meanings to be assigned to them by the skilled addressee were identified. For that reason the evidence was helpful in establishing the background and the common general knowledge but was of little assistance in relation to points of construction.
20. The Claimant based the attack on the tearable taxing means feature on the two French patent applications which both had a device of that type, albeit incorporated into a tap which does not have the pre-characterising features required by the claim. The Claimant based the attack on the engagement means feature on the Waddington and Duval tap. As I have indicated above, it is legitimate to attack the validity of the Patent in this way separating the two features.

Tearable Taxing Means

21. In his Expert Report Mr Gough identifies "the particular configuration of the internal mechanism of the tap" as being a feature of the tap described in Claim 1 of the Patent which is not described in either piece of prior art" and states:

Looking at the tap designs I have seen and applying my general engineering knowledge, the Skilled Addressee would have been aware that there were a number of different configurations of plunger, seal, spring and body, all intended to achieve the same effect namely a reliable, low cost, spring operated valve, manipulated by hand, which by default, is in the closed position. The one adopted in the Patent is just one of the range obviously available. In my opinion, the Skilled Addressee I have described in paragraph 11 above would in 1989, knowing of the prior art and any other designs commonly available to him as part of his general knowledge, would not have regarded the particular configuration described in this part of Claim 1 of the Patent as inventive or non obvious. As I have explained above, the Patent itself does not suggest that there is any thing inventive in this part of the tap.

22. The trouble with this approach is that Mr Gough does not identify the "any other designs commonly available to (the skilled addressee)" that the skilled addressee would adopt while incorporating the other features disclosed in the prior art documents relied on.
23. In cross-examination Mr Gough indicated that the skilled addressee would want a tap that failed in the closed position. This would mean that the piston would have to be lifted to the open position, lifting the elastic membrane up into the tap body and thus opening the outlet. With this arrangement, if the spring fails the pressure from the fluid will automatically close the valve when there is no external force applied to lift the piston.
24. Mr Gough then said that if he was starting from the pleaded prior art and the Waddington and Duval prior art he would probably be starting with a "brain storming session" with a number of designers to come up with a new tap design. I understood this to mean that it would be necessary to disregard the construction of the tap as such in the French patent application and start afresh keeping only the idea of the detachable ring blocking movement of the piston. Mr Silverleaf QC for the Defendants then pointed out to Mr Gough that the acknowledged prior art in the Patent, US Patent No 3442486 was of the type that would fail in the closed position. In fact it is the only design of that type in the case, other than the design of tap disclosed in the Patent. Mr Gough accepted that there is nothing in the French patent application No 2 619 612 which would assist if you were going to use a tap mechanism of the kind shown in the US patent.



25. Mr Silverleaf then asked Mr Gough how he would incorporate features (j) and (k) of claim 1 into the design of the tap in the US Patent. Mr Gough was unable to see a way of getting feature (k) with such a tap. I should explain that the US Patent has a piston that is pulled up to open the outlet. The piston is acted on by a lever device connected to its top end with a cam portion so that as the lever is operated it rolls on the cam which has the effect of lifting the piston. This does not lend itself to the tearable taxing device of the Patent which is required by feature (k) of the claim to form "a stop between the upper portion of the piston and the lower rim of the upper portion of the tap" and this is what was accepted by Mr Gough.
26. He also accepted that neither the other French patent application nor the Waddington and Duval product would assist in getting feature (k). The overall effect of Mr Gough's evidence was that he believed that the tearable taxing device applied to a tap construction as identified in the pre-characterising portion of the claim was obvious but he was unable to identify a logical route based on the prior art and common general knowledge by which the non-inventive skilled person would arrive at such a construction.
27. In my view, this aspect of the Patent is one of those deceptively simple devices which, with the assistance of hindsight appear obvious but in fact are inventive. The means of incorporating the tearable taxing device within the tap construction is elegantly simple and not obvious.
28. Having found that the tearable taxing device feature is not obvious when applied to a tap of the type defined by the pre-characterising clause of claim 1 it is not necessary for me to consider whether or not the engagement means is obvious since claim 1 will be valid in any event. However, I shall have to consider the engagement means in the context of the infringement claim and the Claimant relies, in part, on a squeeze argument. I shall therefore consider the attack on the engagement means aspect of the invention.

Engagement Means

29. As I have said above, the two French patent applications do not show how the tap unit is engaged by the plug since they do not show the plug in the drawings and there is no description of it in the specification. However, the part of the tap unit that is inserted into the plug is shown in cross-section and appears identical to the Waddington and Duval equivalent part of which I was supplied a sample.
30. Mr Graves, the Managing Director of the Claimant company, gave evidence relating to the Waddington and Duval tap and produced a sample and a drawing of the plug on Waddington and Duval paper. The drawing is dated 1983 with amendments up to issue 8 dated 13.1.88. It shows the plug with a cylindrical body and a flange at one end. The internal bore of the cylinder (into which the tap's engagement means fits) is smooth and of a constant diameter. At the flange end of the cylinder the corner between the internal bore of the cylinder and the end face which forms the flange has a radius of 0.7. The engagement means of the tap was inserted into the end of the cylinder distant from the flange and pushed all the way in. At this stage the end of the engagement means would have emerged from the flange end of the cylinder. If the tap is pulled back the ridge at the end of the engagement means catches on the radiussed end of the cylinder.
31. Mr Graves' evidence was that at the time he joined the Claimant company (or more accurately a predecessor in title of the Claimant company) in 1986 they had two tools and were making the Waddington and Duval plug themselves for use with their own tap. He accepted in cross-examination that the tool could not have been made from this drawing since it included a 1988 amendment. He could not say whether the Claimant had been supplied with an earlier copy of the drawing. Mr Graves stated in his witness statement that the plug and engagement means of the Waddington and Duval tap were copied by the Claimant firstly into their Liqui-Flow tap in the mid 1990s and then into the Liqui-Sure tap in issue in these proceedings. He stated that it uses "exactly this means".
32. M Dufrene in his Expert Report commented on the Waddington and Duval tap (which he called the "Press-Tap"), particularly with respect to its engagement with the Plug and differentiated it from the engagement means of the Patent in the following terms: The purpose of this element of the claim is to fix the tap in such a way that it cannot be removed. This is achieved by moulding into the plug a high-angled profile which will catch an edge on the engagement means of the tap and prevent withdrawal. As indicated above, one of the problems with the Press-Tap was that it was capable of being pulled apart and this was partly because the internal rim of the plug was rounded.
33. This is certainly consistent with the Waddington and Duval 1983-88 drawing I have referred to above and also a drawing reproduced by M. Dufrene which he said had been supplied to him by Waddington and Duval in 1986. However, the Claimant disclosed another drawing dated 31^st July 2001 apparently made by Master Tools Ltd which is said to be a drawing of the Claimant's plug, although there is no evidence as to when they adopted this design. The plug in this drawing looks essentially the same except in two respects, namely: (1) the internal diameter of the cylinder is slightly tapered, reducing in diameter towards the flanged end; (2) at the flanged end there is a slight step where the diameter increases before the radiussed portion.
34. It was Mr Graves' evidence in the witness box that this drawing was made from a sample of the Waddington and Duval plug manufactured by the Claimant at that time. This sample was said to have been given to Master Tools to make the drawing. There are, in fact, serious errors on this drawing. In particular one of the dimensions given is clearly wrong and one of the section drawings shows a solid piece of plastic across the outside opening of the cylinder. Whatever the purpose of this drawing I cannot be certain that it accurately reflects the shape of the plug before 2001. It is, however, the shape that is used by the Claimant with its Liqui-Sure product.
35. That is not the end of the matter however since the Claimant's expert, Mr Gough, has given reasons in a supplemental report, as to why a toolmaker would introduce the two differences I have identified above for ease of manufacture of the part shown in the earlier Waddington and Duval drawing.
36. He says that the tool would have to be in four parts and the toolmaker would put the split line at one end or the other of the part so that any flashing at the join would not interfere with the function of the part and could be pushed out of the way. The toolmaker would also introduce a slight taper towards the end where the split line was located to enable easy removal of the core. The logical direction to have the taper would be towards the inside end as shown in the Master Tools drawing.
37. In cross-examination Mr Silverleaf put to Mr Gough that the Waddington and Duval drawing has a number of details on it which relate to the toolmaker and not to the final part. Mr Gough accepted that to be the case and also accepted that it was probable that most alterations to the part made by the toolmaker would be added to the drawing.
38. It is clear to me that these alterations to the shape of the plug were made at some time for toolmaking reasons but there is insufficient evidence for me to say that these alterations were made before the priority date of the Patent. For this reason, even if the engagement means shown on the plug of the Master Tools drawing have features (l) to (p) of claim 1, I find that the Claimant has not established on the balance of probabilities that those features were made available to the public before the priority date of the Patent. If the part was made in accordance with the Waddington and Duval drawing at least up to 1989, and it is M. Dufrene's evidence that it was, then this suggests that there was no reason to make those alterations at that time. I find that the Claimant has failed to establish that it was obvious to make those alterations to the original Waddington and Duval unit.
39. I turn now to infringement.

Infringement

40. Reproduced below are photographs from the Product Description showing the assembled product and the component parts.





41. The only claim asserted to be infringed is claim 1. The Claimant says that its product does not infringe for a number of reasons. These can be divided into three headings: (1) the tap is not constructed in accordance with the pre-characterising part of the claim; (2) the product does not have a tearable taxing means, and; (3) the engagement means for attaching the tap to the plug does not have the features required by the claim.

The pre-characterising features

42. Three features of the pre-characterising part of the claim are identified as being absent: (1) the piston is not loaded by a spring so as to act on the elastic membrane (features (c) and (d); (2) the sealing membrane is not integral with the body feature (d), and; (3) the upper body does not form a guide for the spring loading the piston feature (h). Points (1) and (3) are inter-related and I shall deal with them together.

No spring

43. The Claimant's product has no spring as such. The membrane which fills the outlet hole in the bottom of the tap body is made of an elastic material. It is held around its periphery against the top of a circumferential ridge in the bottom portion of the tap body but above the passage that allows liquid to flow into the tap from the container. The cap to the tap has two downward projections that sit on top of the periphery of the membrane holding it on the ridge.
44. In the rest position the membrane pushes into and fills the outlet hole. The piston is attached to the bottom centre of the membrane. When the piston is lifted it pulls up the centre of the membrane. The membrane as a whole cannot rise up in the tap because it is held around the periphery. As a result, when the piston pulls up the centre of the membrane it plastically deforms the membrane and the membrane exerts a downward force on the piston. If the piston is released the membrane will return to its initial position pulling the piston down with it. The membrane behaves as a spring acting upon the piston. The upper portion of the tap body acts as a guide for the piston.
45. The Claimant grudgingly accepts that "one could argue that the piston is loaded by a sprung device – i.e. the membrane, although only when open rather than when closed. ... But one cannot possible say that the piston acts on the membrane. It is the other way around."
46. It is necessary to construe the claim in the context of the specification, including the drawings. The specification describes an alternative embodiment which is illustrated in Figure 5.



47. This embodiment is described in the passage on page 6 lines 11-19 of the specification:

Figure 5 shows a variation of the invention in which the elastic sealing membrane 4' is a self retracting membrane so-operating by its rear end with a retaining profile 20 in the form of an internal annular shoulder of the body of the tap 9, this membrane 4' co-operating by means of a recess 21 with the lower end 22 of the piston 2 by nesting thereof, said piston 2 being guided in the body of the tap 9 and being returned to the closure position of said tap by the membrane 4' without the use of a spring. (emphasis added).

48. This embodiment would appear to be the intended subject of claim 6:

Unit according to claim 1, characterised in that it is provided with an elastic sealing membrane in the form of a self-retracting membrane co-operating by its rear end with a retaining profile in the form of an internal annular shoulder of the body of the tap, this membrane co-operating by means of a recess with the lower end of the piston by nesting thereof, said piston being guided in the body of the tap and being returned to the closure position of said tap by the membrane exerting a spring function.

49. The Defendants argue that the claims should be construed in such a way as to encompass the specific embodiments described in the specification within the scope of the claims. The Claimant, on the other hand, relies on Telesonic's Patent [2004] RPC 38 at §39. In that case Laddie J was construing a patent claim in which the words "the resonator has rod-type resonators or at least one circular rod". One of the drawings in the specification illustrated an alternative design described as being "without resonators". Laddie J. recited these facts and then said: "How that falls within the claims of the patent is not clear. It may be an embodiment which has been stranded by amendments to the claim. Whatever its origin, it throws no light on the matter of how the word "circular" is used in the patent."
50. I do not think that authority helps in the present case. The learned Judge was attempting to construe the word "circular" and not the word "resonator". If he had been trying to decide whether the word resonator in the claim actually included something that was not a resonator but performed the function of a resonator then that would be closer to the problem before me. Rather than seeking to draw analogies from cases with different facts one has to go back to the basic principles of construction of patent claims.
51. The principles of construction of patent claims as gleaned from Lord Hoffmann's speech in the House of Lords in Kirin-Amgen [2004] UKHL 46 were set out in a conveniently concise list by Jacob LJ in Mayne v Pharmacia [2005] EWCA Civ 137 at §5:

"(a) The first, overarching principle, is that contained in Art 69 itself.

(b) Art 69 says that the extent of protection is determined by the terms of the claims. It goes on to say that the description and drawings shall be used to interpret the claims. In short the claims are to be construed in context.

(c) It follows that the claims are to be construed purposively – the inventor's purpose being ascertained from the description and drawings.

(d) It further follows that the claims must not be construed as if they stood alone – the drawings and description only being used to resolve any ambiguity. Purpose is vital to the construction of claims.

(f) Nonetheless purpose is not the be-all and end-all. One is still at the end of the day concerned with the meaning of the language used. Hence the other extreme of the Protocol – a mere guideline – is also ruled out by Art 69 itself. It is the terms of the claims which delineate the patentee's territory.

(g) It follows that if the patentee has included what is obviously a deliberate limitation in his claims, it must have a meaning. One cannot disregard obviously intentional elements.

(h) It also follows that where a patentee has used a word or phrase which, acontextually, might have a particular meaning (narrow or wide) it does not necessarily have that meaning in context.

(i) it further follows that there is no general "doctrine of equivalents".

(j) On the other hand purposive construction can lead to the conclusion that a technically trivial or minor difference between an element of a claim and the corresponding element of the alleged infringement nonetheless falls within the meaning of the element when read purposively. This is not because there is a doctrine of equivalents: it is because that is the fair way to read the claim in context.

(k) Finally purposive construction leads one to eschew what Lord Diplock in Catnic called (at p.243):

"the kind of meticulous verbal analysis which lawyers are too often tempted by their training to indulge.""

52. Applying these principles of construction I have no difficulty in reading integers (b), (c) and (d) of the claim as being fulfilled by the elastic sealing membrane acting on the piston in the manner of a spring in resisting movement of the piston. It is apparent when one tries to open the Claimant's tap that the elastic membrane does "load" the piston in that there is resistance from the membrane to any, even slight, movement of the piston. In the context, the reference to the piston acting on the elastic membrane is satisfied by the fact that the piston pulls the membrane out of the outlet hole when it is pulled up.
53. So far as integer (h) is concerned requiring the upper portion of the tap to form a guide for the piston and for the spring loading the piston this is satisfied by the upper portion guiding the piston which is attached to the membrane. By guiding the membrane the piston keeps the membrane central in the tap body and therefore guides it.
54. There is one other factor that arises. Claim 6 in the Application for the Patent is slightly different from claim 6 as granted in that it has the words "without the use of a spring" instead of "exerting a spring function". "Without the use of a spring" are the words used in the description of this embodiment in the specification. The Claimant says that it does not need to rely on this change of wording but that, if they do, it helps it and it is legitimate to take it into account. It says that it shows that there has to be a spring (because of the dependency on claim 1) and so the amendment had to be made.
55. The Defendants say that it is not legitimate to look at the application to construe the claim and that the words in question still appear in the second embodiment.
56. I do not know why the amendment was made but I do not find it helpful to my task of construing the claim.

Membrane not integral with the body

57. The Claimant argues that because the membrane in its tap will fall out if the top is forced off it is not integral with the body. It is clear from the specification and drawings as a whole that the purpose here is for the membrane to be attached to the body in some way so that it will not allow liquid to flow between it and the body. The top is part of the body and when the body is assembled the membrane is held firmly in place between the top and the bottom of the tap. It is integral with the body. When the top is forced off, the body is no longer a single unit and it is irrelevant that the membrane falls out. The claim is not referring to the status of the membrane when the tap is disassembled but rather when it is assembled. In the assembled state the membrane is integral with the tap body.

Post-characterising integers – taxing means

58. The Claimant says that to be a taxing device it is not enough for there to be merely a "tearable ring forming a stop": rather, to be a taxing device "it must be suitable for receiving the taxing licence. The patent itself makes it plain that the problem is to have something with a sufficient surface area ... That is why the patent provides for a 'medallion' attached to a tear ring in the embodiment..." (Skeleton §75) In its written closing submissions the Claimant argues "the tear off strip of the DuPont product has neither the physical characteristics nor the purpose of the taxing device. And today's wine boxes no longer need to be taxed..."
59. The Claimant's product has a tearable ring forming a stop with a relatively narrow tab projecting down the front of the tap unit. This tab facilitates the tearing of the ring.
60. The relevant passage in the Patent relating to the taxing device states:

In fact, the known taps with spring-loaded pressure-operated keys or valves do not generally have a surface area allowing the attachment of a taxing means such as a stamp or a licence which is to be removed before the first use. To overcome this drawback, it has been proposed that the entire tap be covered with an auxiliary element forming a cover consisting of a heat-shrinkable cap fixed on the container and carrying the taxing licence which has to be destroyed to free the tap for its first use. (page 1 lines14-23)

61. This does not require a large area to attach the taxing means and indeed the Claimant did not adduce evidence as to how large the "stamp or licence" would have to be. What it does require is an area over which the taxing means can be applied in such a manner that the tap cannot be operated without destroying the taxing means. This Patent allows this to be done by attaching the taxing means over the area of the tearable ring that must be torn in order to use the tap. In the Claimant's product there is an appropriate such area. Although the specific embodiment provides a medallion for this purpose the claim is not so limited and that is the subject of claim 4 which is dependent on claim 1. I do not read claim 1 in the context of the specification as a whole as requiring the tearable taxing device to be used for the purpose of accepting a stamp or licence but merely to be suitable for such purpose.
62. I find this feature of claim 1 to be present in the Claimant's product.

Post-characterising integers – engagement means.

63. The Claimant's argument centres on the meaning of the "wide groove" in the engagement means in integer (l) and the "annular projection" of the plug in integer (m). The Claimant's engagement means has three ridges (sealing ridges) spaced apart along the outside of the cylinder with a fourth ridge near the end which slopes down toward the end. The Defendants say that the area between the third and fourth ridges is a wide groove. The Claimant says that a groove must be below the surface rather than an area between two ridges. I believe that this is a matter of perspective and is akin to the argument as to whether a glass is half full or half empty.
64. It is not possible to construe the groove separately from the projection. The two are intended to co-operate together to provide essentially a permanent fixation. The claim is very specific about the projection. Its features are defined in detail. It must be sloping towards the exterior of the plug, i.e. away from the end with the flange, it must have a shoulder at an acute angle towards the interior of the plug and the shoulder must be spaced from the external edge by a distance corresponding to the spacing of the groove.
65. The Defendants say that these features are present in the Claimant's plug by reason of the fact that the internal diameter of the plug is tapered toward the interior end of the plug and so is sloping towards the exterior and the configuration at the interior end of the plug provides the shoulder.



66. Reading the claim in the context of the specification as a whole I am unable to construe the projection which is to be caught by the wide groove to cover what is actually, as can be seen from the drawing reproduced above, an indentation which catches a ridge on the engagement means. No-one examining the Claimant's plug would believe that there was a projection on the inside surface. Whilst M. Dufrene adopted the Defendants' arguments as set out in their Statement of Case I did not understand him to be suggesting that there was a noticeable projection on the plug. M. Dufrene accepted that the Waddington and Duval plug had no such projection and there is no readily discernible difference between it and the Claimant's plug.
67. The specific and detailed description of the engagement means in the claim would, I believe, lead any reader of the specification to understand that this was an intentional limitation on the part of the patentee. The difference between the Claimant's plug and the Waddington and Duval plug, on the assumption that there is a difference, is very slight. M. Dufrene's evidence was that prior to 1988 it was possible to remove the Waddington and Duval plug, particularly in a hot summer when the plug was softer. It is entirely reasonable that the Defendants should want to have engagement means that would be much more difficult to remove from the plug and would seek to avoid including the Waddington and Duval plug and engagement means from their claims.
68. In the circumstances I find that the Claimant's engagement means and plug do not have the features required by claim 1 and so there is no infringement.
69. For the reasons given above I find the Patent valid but not infringed.