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	England and Wales Court of Appeal (Civil Division) Decisions
You are here: BAILII >> Databases >> England and Wales Court of Appeal (Civil Division) Decisions >> Sara Lee Household & Body Care Ltd v Johnson Wax Ltd [2001] EWCA Civ 1609 (20 November 2001) URL: http://www.bailii.org/ew/cases/EWCA/Civ/2001/1609.html Cite as: [2001] EWCA Civ 1609, (2002) 25(2) IPD 25008

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IN THE SUPREME COURT OF JUDICATURE
COURT OF APPEAL (CIVIL DIVISION)
ON APPEAL FROM CHANCERY DIVISION
MR DAVID YOUNG QC (SITTING AS A DEPUTY
HIGH COURT JUDGE)

		Royal Courts of Justice Strand, London, WC2A 2LL Tuesday 20th November 2001

LORD JUSTICE ALDOUS :

1. Sara Lee Household & Body Care UK Limited are the registered proprietors of EP 0538 957 which has the priority date of 22nd October 1991. They alleged that that patent had been infringed by two products produced by Johnson Wax Limited, referred to as the Mark I and Mark II respectively. Johnson Wax disputed that allegation and contended that the patent was invalid. Those disputes came before Mr David Young QC sitting as a deputy judge of the Patents Court. In his judgment dated 8th December 1999 he held that neither the Mark I nor the Mark II infringed. He also rejected the attack on the validity of the patent. With leave of the judge Sara Lee appeal and Johnson Wax cross-appeal.

The Patent

2. The patent is for an invention entitled "Cleansing and Freshening Unit for a Toilet Bowl". Such units have the two-fold purpose of spreading a fresh odour in a toilet room and introducing an active substance, such as disinfectant, into the flushing water.
3. As is usual, the specification opens with an acknowledgement of the prior art. It then refers in column 1 line 34 to the drawbacks of the known devices in these terms:

"A drawback of the known blocks of cleansing and freshening substances is that they have a short life-time, the dosing is uneven and such blocks contain fillers that may be detrimental to the environment. An important drawback is that the air freshening effect of such blocks is limited because with each flush of the toilet, the active substance that is dispensed disappears immediately along with the flushing water."

4. The invention is said to have the object of circumventing those drawbacks. To that end the unit according to the invention is characterised by the features of claim 1. The specification then describes the two-fold purpose in this way:

"When the toilet is not used, per unit time a substantially constant amount of liquid will evaporate via the porous mass and thus have an air freshening effect. With each flush, a likewise substantially constant amount of active substance will be carried along by the flushing water and thus have a cleansing effect. It is important that with the unit according to the invention, a double-action is obtained, consisting, on the one hand, of a continuous constant dispensation of freshening substance, and, on the other, of a constant measuring of cleansing action with each flush."

5. One practical example of the invention is described with the aid of three figures. Figure 1 (reproduced below) is the unit depicted directly before the toilet has been flushed.

Figure 1


6. As illustrated in Figure 1 of the patent, the unit is suspended by a hook (2). The liquid to be dispensed is contained within the inverted bottle (3). In the mouth of the bottle is a "spongy closure member" (4B). That closure member is in contact with a generally disc-shaped porous member (4A).
7. The operation of the unit is described at column 3 line 28 in this way:

"The unit is suspended from the inwards overhanging rim of a toilet bowl by the means of the hook (2), in such a manner that the container (1), with the bottle (3) facing the wall of the bowl, hangs partly under the rim. Thus, the unit has a constant effect in that liquid is absorbed from the bottle via the liquid-permeable member (4B) in the porous member (4A) and perfume evaporates therefrom so as to spread a fresh odour into the toilet room.

When the toilet is flushed, 'instant action' is initiated in that flushing water falls from under the rim of the toilet bowl onto the unit, flowing along the ribs (17) over the porous member (4A) and carrying along active substances for cleansing the bowl. After flushing, a fresh solution of the above-mentioned cleansing and odourising substances remain behind in the water seal of the toilet bowl, as mentioned above.

As indicated above in figure 2, after a flush a layer of water is left behind the porous mass (4A), the height of this layer of water being determined by the passages (8) serving as overflows. The residual Water flows slowly through the disc-shaped member (4A) and the apertures (6) in the container bottom (5). In the process, this residual water removes active substances and any residues of the perfume evaporation from the member (4A). The member (4A) is thus purified and at the same time an important delayed action is obtained, namely, the delivery of active substances to the toilet bowl is continued for some time after each flush."

8. The relevant claims conveniently broken down by the parties into features are as follows:

"Claim 1

(i) A cleansing and freshening unit having the twofold purpose of

(ii) spreading a fresh odour in the toilet room and

(iii) introducing active substances into the flushing water with each flush, the unit comprising:

(iv) a reservoir (3) for an active substance, such as liquid containing cleansing and air freshening agent;

(v) suspension means for suspending the unit from the rim of a toilet bowl;

(vi) a porous mass (4A) which is

(vii) arranged in the path of the flushing water when the unit has been suspended in a toilet bowl;

characterised in that

(viii) the reservoir has a mouth (1) in which

(ix) a liquid-permeable closure (4B) is arranged such that

(x) the reservoir (3) has its contents in constant communication with the porous mass (4A) when the unit has been suspended in a toilet bowl.

…

Claim 2

(i) the suspension means comprises a hook (2)

(ii) which is connected to a container (1)

(iii) being open at the top

(iv) and having a bottom (5) provided with perforations (6)

(v) as well as a retaining means (9,10) for the mouth (11) of the liquid reservoir (3),

(vi) which retaining means are arranged at the bottom (5),

(vii) the porous mass (4A) extending on the container bottom (5) over the perforations provided therein."

Infringement

9. The infringements were marketed by Johnson Wax as the "Toilet Duck System". Each pack contained two separate components, namely a delivery platform and a bottle containing the liquid to be dispensed.

The Mark I

10. The Mark I with a bottle attached is shown below.
11. The bottle 5 has a shaped neck 6(a) which is closed by a disc 6(b). When the bottle is inverted and pressed into the housing 1 of the delivery platform, the oblique topmost part of the inlet chamber 8 fractures the disc so as to cause it to be pivoted to the position shown in the drawing. The inverted bottle then rests on the shelf 9 with the inlet chamber 8 fitting snugly up through the aperture of the bottle.
12. The housing 1 comprises the cylindrical inlet chamber 8 and an outlet chamber 10 through which liquid from the bottle is conveyed to a porous pad 7. The inlet chamber 8 is located on the shelf 9. It communicates with the outlet chamber 9 via a circular hole 9(a) which is about 3 mm in diameter. Vent holes 12, about 1 mm in diameter, are formed in the pad 7 so as to allow air from beneath the pad to pass into the bottle via the outlet chamber 10, the hole 9(a) and the inlet chamber 8.
13. Johnson Wax contended that there was no infringement as features (viii), (ix) and (x) were not present in the Mark I. Sara Lee submitted that the part consisting of the inlet chamber 8, the shelf with the hole 9(a) and the outlet chamber 10 was "a liquid-permeable" closure which was arranged in accordance with feature (viii) to have the effect of feature (x) of claim 1. Thus there was infringement. The main dispute between the parties turns upon the ambit of protection provided by the words "a liquid-permeable closure" in feature (ix).
14. The judge approached the task of interpretation correctly. He said:

"17. CONSTRUCTION

The extent of protection conferred by such claim is to be determined in accordance with section 125(1) and (3) of the Patent Act 1977, namely following the guidance provided by the Protocol on the Interpretation of Article 69 of the European Patent Convention. The claims are to be interpreted by the description and any drawings. They are not to be interpreted over literally nor as a guideline as to what the patentee has contemplated - rather they are to be interpreted as defining a position between these two extremes which combines a fair protection for the patentee with a reasonable degree of certainty for third parties.

In this regard the three Improver questions posed by Hoffmann J. have been cited by the Defendants. In addition the Defendants have referred to the observations of Hoffmann L.J. in Step v. Emson (1993) RPC 513 at 522.

"the well known principle that patent claims are given a purposive construction does not mean that an integer can be struck out if it does not appear to make any difference to the inventive concept. It may have some other purpose buried in the prior art and even if this is not discernible, the patentee may have had some other reason of his own for introducing it".

and to Laddie J. in Brugger v. Medic-Aid (1996) RPC 635 at 649

"if a patentee has chosen to define the characterising part of his claim in narrow terms the Court should not rewrite it in broader language simply because it thought a wider form of wording would have been easy to formulate".

15. Both parties agreed that there were no technical words or phrases in the claims or in the specification. It was therefore surprising that the parties inflicted upon the judge evidence from professors who told him what they believed certain words in the claim meant. I deplore the introduction of such evidence as it prolonged the trial and increased the costs. Of course, scientific witnesses are needed to explain technical terms and the way that a particular apparatus or process works, but they are not experts in construction of patent specifications. In particular, their expertise, which requires precise use of words, is not useful when applying the Protocol. The task of construction is for the Court, having been instructed on technical words and phrases and the common general knowledge in the art. That task cannot be delegated to scientific witnesses.
16. Sara Lee contended that the words "liquid-permeable closure" have a functional meaning. They defined a closure that in operation prevented the flow of liquid out of the reservoir except as "demanded" by the porous mass and then in the controlled manner so that the porous mass holds only an amount of liquid suitable for dosing the water during flushing and/or freshening the toilet room by evaporation.
17. I am quite certain that that contention is erroneous. Mechanical devices could be made to carry out that function which could not in any sense be said to be "liquid-permeable" or operate as a closure of any kind. The claim itself sets out in features (i), (ii) and (iii) the functional requirements of the claimed apparatus. That is to say, the unit has a twofold purpose of spreading a fresh odour in the toilet room and introducing active substances into the flushing water. The claim then goes on to set out the features of such a device. Feature (ix) requires there to be a liquid-permeable closure arranged in a particular way (see feature (x)), so that the reservoir has its contents in constant communication with the porous mass.
18. The judge rightly described the phrase "a liquid-permeable closure" as an oxymoron. Having considered the dictionary definitions of the word 'permeable' he correctly in my view stated:

"21. The phrase "a liquid-permeable closure" is an oxymoron in the sense that the closure allows liquid to flow from the reservoir to the porous pad (4A). Permeable connotes that the holes or pores in the closure barrier are such that the rate of flow of liquid passing through is significantly reduced - if this were not the case then the liquid-permeable closure would merely operate as a conduit without regulating the flow."

19. The Protocol requires construction to be carried out in the context of the whole specification. A close reading of it illustrates why the words "liquid-permeable closure" were used. In the specific embodiment a spongy closure is used which the skilled addressee would appreciate was a permeable material. The specification goes on to describe how the refillable bottle 3 containing liquid can be inverted and placed so that the spongy liquid-permeable closure is in liquid-transmissive contact with the porous member 4A. That enables (see column 3 line 31) the liquid to be "absorbed from the bottle via the liquid-permeable member 4B into the porous member 4A". Thus the spongy member 4B closes the mouth of the bottle when inverted for insertion into the bottle. It is liquid-permeable in the sense that it allows the liquid from the bottle to be absorbed into the porous pad.
20. Mr Thorley QC, counsel for Sara Lee, submitted that the word "permeable" as used in the phrase "liquid-permeable closure" only meant that the liquid could pass through the closure. That does not in my view give the word the appropriate meaning in the context of this specification. The notion of permeability requires a restricted and diffused movement. It is not necessary to define it. The task of the court is to decide whether the Mark I has a liquid-permeable closure.
21. The mouth of the bottle in the Mark I is partially closed by the shelf 9 with its 3 mm hole 9(a). That hole is a conduit through which liquid can be poured. The shelf with the hole is not liquid-permeable. Also, because of the hole, it is not a closure.
22. Mr Kitchin QC who appeared for Johnson Wax also drew attention to the fact that the part which was alleged to close the mouth of the bottle was not in the mouth of the bottles as required by features (viii) and (ix). Mr Thorley countered that by submitting that the liquid-permeable closure consisted of the parts 8, 9 and 10. That being so, a substantial part of the closure member was in the mouth of the bottle and that was all that the claim required.
23. I prefer the submissions of Mr Kitchin. The part 8 punctures the seal of the bottle and helps to position the plate 9 in sealing engagement with the bottle. The only part which could restrict flow is the plate 9. That is just outside of the mouth of the bottle. Thus Mr Kitchin is correct that the part which could act as a closure does not literally satisfy the claim. However that is unimportant. As the Protocol makes clear, the ambit of the claim need not be confined to the literal meaning of the words. Nobody reading the specification could believe it would make any difference to the way the invention would work by placing what can be loosely termed the bung, at the mouth of the bottle rather than within it.
24. Mr Thorley rightly pointed out that the court should avoid confining the ambit to the literal meaning or expanding it by using the claims as a guideline. The task of the court is to give fair protection for the patentee with a reasonable degree of certainty for third parties. He accepted that the protocol questions referred to in Wheatley v Drillsafe Ltd [2001] RPC 133 could give guidance. The evidence, he submitted, established that the Mark I arrangement had no material effect upon the way the invention worked and that would have been obvious to the skilled addressee at the date of publication of the patent. Further there was nothing in the specification to lead the skilled addressee, who read the specification, to believe that strict compliance with the phrase "liquid-permeable closure" was necessary. That being so, the claim should be construed to cover the Mark I.
25. In general Mr Kitchin did not suggest a contrary approach, but he submitted that a proper understanding of the evidence and the specification led to the contrary conclusion.
26. The judge refused to give the claim the width sought by Mr Thorley. He said:

"51. (a) Liquid-permeable closure: the absence of a closure which is liquid-permeable will allow air to vent into the reservoir and avoid the problems which are inherent in a liquid-permeable closure such as the porous/spongy bung disclosed in the patent. That this is a real problem with a liquid-permeable closure can be seen from the Claimants' later filed patent application EP 0785315 where it is acknowledged in Col 1 lines 5 to 19 that a drawback of the device the subject of the patent in suit is that due to the porous bung air can only flow into the bottle/reservoir with difficulty so that there is a risk of reduced pressure being formed in the bottle which substantially limits the draining of the bottle.

52. Much evidence was directed to the extent air bubbles would penetrate a porous bung. Prof Nikolov in Appendix 2 to his First Report carries out a calculation much criticised by the Claimants. I have not found any of this evidence directed as it is to a specific case of any assistance.

53. However Prof. Luckham does accept that it would be harder for an air bubble to go up through a porous mass than it would be to go up through a fairly large hole (see Day 2/336). Furthermore the passage of air through a porous material (as opposed to a single hole) could well be affected by becoming clogged with particulate material (see Day 2/346).

54. I consider that the substitution of a 3mm hole for a liquid-permeable closure such as a porous bung will have a material effect on the way the device will operate in particular with regard to the regulation of liquid from the reservoir to the porous pad/tray."

27. I believe that the judge's conclusions in those passages are correct. The patent teaches that the liquid-permeable closure restricts flow until it is in fluid-trasmissive contact with the porous pad. The liquid is then absorbed from the bottle. The operation of the Mark I is different as all the witnesses made clear. The shelf with the 3 mm hole does not restrict or regulate the flow.
28. Mr Coe, a consultant working in the packaging trade, did not profess to have expertise on fluid flow, but said during cross-examination by Mr Kitchin:

"Q. Mr Coe, I am having some difficulty with this. Perhaps you can help me. If that hole in the shelf was made 4, 5 or 6 mm in diameter as opposed to 3 mm in diameter, are you in a position to assist the court as to whether or not in the one case rather than the other case it is going to affect the flow to a greater or lesser extent? Do you actually know or are you speculating?

A. No, I do not know and I am giving you a view which is based on my experience and expectations. What I would expect is that if the thing was perfectly assembled, whether the diameter is 3 mm or 4 mm, in all probability, would be of little consequence. I can imagine that as one reduces the diameter at some point that could become the controlling factor in the rate at which material flows out and I am unable to postulate what that diameter is but certainly it could become infinitesimally small and at that point it would regulate the flow. At 3 mm or 4 mm I do not believe it would regulate the flow in the intended operating circumstances of the device. But all I am saying is that the intended operating circumstances will not always be satisfied."

29. Professor Luckham, the expert called by Sara Lee was asked what were the factors which controlled the flow in the Mark I when in the dry state and in the wet state. He accepted that they were the partial vacuum in the bottle, viscosity, hydrostatic pressure and capillary action. He was then asked (Ev. 2 at page 280) whether he could think of anything else which was controlling the flow in the Mark I in the dry condition. He answered no. He was then asked about the controlling factors in the wet conditions and agreed that they were the same as in the dry state with some effects from the effect of concentration. The cross-examination on this matter concluded in this way:

"Q. Can we agree this far. That in the wet and the dry condition, the factors therefore which are controlling the flow are hydrostatic pressure gravity?

A. Yes.

Q. Gravity?

A. Yes.

Q. Concentration gradient effects?

A. Yes.

Q. On which we have differed slightly?

A. Indeed, yes.

Q. Partial vacuum in the headspace?

A. Yes.

Q. And viscosity within the pad which may tend to reduce the speed.

A. Yes, that is right. I do not know if you said capillary.

Q. And capillait.

A. Yes.

Q. Those are the factors which control the flow?

A. Yes."

Thus Professor Luckham did not believe that the shelf with its hole was a factor controlling flow.

30. Dr Carter initially thought the hole in the shelf of the Mark I had an effect upon the flow rate, but said in his second report that he had changed his mind after seeing the report of Professor Nikolov, the expert called by Johnson Wax. He maintained that view in cross-examination.
31. Professor Nikolov said that the porous pad as shown in the patent would control the flow, but the hole in the Mark I would not. It was his view that even if the shelf of the Mark I was taken away completely, the only flow would be that caused by the capillary action of the porous pad. The amount sucked out was not controlled by the hole in the shelf.
32. Mr Thorley relied on the results of Experiment I. In that experiment the Mark I bottle was inserted into the housing with the porous pad removed. Nothing came out after the initial drop or two. Thus Sara Lee assert that the shelf with the 3 mm hole in it must regulate the flow. That conclusion cannot be drawn from that experiment. All that it demonstrated was that the hydrostatic pressure did not overcome the partial vacuum in the headspace. When the porous pad is inserted the capillary action will suck out a small amount of fluid. That is not regulated in amount nor rate by the size of the hole in the shelf. The hole acts as a conduit for the fluid.
33. There is another difference in operation between liquid-permeable closure of the patented invention and the Mark I. Because the closure is only liquid-permeable, it is harder for air to pass through it to relieve the partial vacuum in the bottle and thus allow liquid to be sucked out than through the hole in the shelf of the Mark I. That was appreciated by Sara Lee who filed another patent application for a device with venting holes to overcome the problem. That difference was accepted to be present by Professor Luckham as the judge held in paragraph 53 of his judgment set out above.
34. Protocol question 1 – Does the variant have a material effect upon the way the invention works? – requires the court to examine whether there is equivalence. In this case there may be equivalence of result, but not of construction. Claim 1 is for an apparatus. The Mark I does not operate in the same way as the claimed invention. A liquid-permeable closure provides a regulator of flow and a restriction to air bubbles. The shelf of the Mark I with its hole does not regulate flow nor provide a restriction to air bubbles.
35. Mr Thorley submitted that if the first Protocol question was answered in the affirmative, then the second should be answered in the negative. In essence he submitted that if the Mark I was in fact a functional equivalent then the second question should be answered taking into account knowledge that the Mark I works. He submitted: "The point of the question is to say 'when I see these two [the claimed device and the Mark I] do I realise that they are functioning in the same way or do I think they are functioning in a different way?"
36. I cannot accept that submission. The second Protocol question is designed to ensure a reasonable degree of certainty for third parties. They need to be able to ascertain the ambit of the monopoly at the date when the patent is published. They know that the ambit cannot be determined by the literal meaning of the words and that to be fair to the patentee a party cannot necessarily avoid infringement by taking the invention in a disguised but equivalent form. However to be fair to the public the equivalence must be clear or obvious to the skilled addressee who reads the specification. He should not have to build a device and test it. A device that he appreciates is an immaterial variant will probably fall within the ambit of the monopoly. However if the variant is not obviously immaterial, it would normally be wrong for the public to be prevented from making that variant. It is the patentee who chooses the words of the claim.
37. I do not believe that there is evidence which establishes that it would be obvious to the skilled addressee that the shelf and hole of the Mark I would have no material effect upon the way the invention worked. That perhaps is not surprising in view of the conclusion reached on the first question.
38. The answers to the Protocol questions indicates a finding of non-infringement but they can only be an aid to arriving at the result required by the Protocol. Fair protection to the patentee requires some latitude in construction of features (viii), (ix) and (x). However to construe the words "liquid-permeable closure" to cover the Mark I would move beyond what could be termed fair protection to the patentee. I conclude that the judge was right to hold that the Mark I did not infringe claim 1.

The Mark II

39. The Mark II is constructed in the same way as the Mark I save that, instead of a porous pad 10, a tray is used as shown below:

Figure 7


40. It was accepted by the parties that the Mark II did not infringe if the Mark I did not. Thus for the reasons I have given I conclude that the Mark II does not infringe. I can therefore deal shortly with the submission of Mr Kitchin that, whatever the conclusion reached on the Mark I, the Mark II did not infringe claim 1 as the porous pad of feature (x) was not present.
41. Mr Thorley accepted that the substitution of a tray for a porous pad meant that there could not be literal infringement. He went on to submit that the tray was an obvious immaterial variant and that the claim should be construed so that the Mark I fell within its ambit.
42. The judge held that the tray was an obviously immaterial variant, but that the patent should be read as requiring strict compliance with this feature. He said:

"55. (b) porous mass: whilst the substitution of a porous pad by a plastic tray will have a material effect on the way the delayed action works (claim 2 feature) it is less clear to me what effect a plastic tray has over the general operation of the device compared with the same device with a porous pad. Both devices will allow liquid to be spread over the surface of the pad/tray and on flushing both devices will allow the active substances to be flushed away with each flush. It is true that the capillary effect of an open channel of the Mark 2 plastic tray is less than that of a porous pad and there may be a Maragoni effect due to differences in surface tension not present in a porous pad. However I consider these differences are matters of degree and do not affect broadly how the invention claimed in claim 1 works.

56. (c) Perforations in the bottom of the container : the absence of such perforations will have a material effect on the way the device operates in that their purpose is to hold up or delay the introduction of cleansing liquid into the toilet bowl.

57. (2) Even if the variation would have no material effect on the working of the invention would this fact have been obvious at the date of publication of the patent to a reader skilled in the art. This question only applies to the substitution of the porous mass by the plastic tray of the Mark 2 device. The evidence is that a skilled rheologist would have appreciated that a plastic tray with open channels would operate by a capillary action and/or diffusion action (in the wet) in a manner similar to that of a porous pad - see Luckham para 42 First Report and Mr. Coe para 48 First Report not cross examined.

58. (3) Are the words of the claim essential requirements of the invention such that strict compliance with their primary meaning was intended by the patentee. The requirement of a liquid-permeable closure is not simply to control or regulate the flow of liquid from the reservoir to the porous mass. It also has the advantages of allowing the reservoir to be assembled to the container by holding it upside down in the manner described. Furthermore as a spongy bung it allows the reservoir to be refilled.

59. Together with the porous mass it allows liquid to be regulated in the manner claimed. Both items are in my view essential requirements of the invention. Indeed the Claimants in par 57 of their closing submissions rely on both the porous mass and the liquid-permeable closure as being part of their inventive concept. Furthermore the porous mass is essential to the delayed action feature which is stated to overcome an important drawback of the prior art solid rim block devices (see Patent Col 1 lines 37 to 45 Col 2 lines 5 to 23 and Col 3 lines 44 to 55).

60. Hence even if, contrary to my view, the Defendants' plastic insert has no material effect on the working of the invention claimed in claim 1, I consider a skilled reader would understand that a liquid-permeable closure combined with the porous mass to be essential requirements of the invention."

43. Professor Luckham accepted in cross-examination that there were differences in the way a tray and a porous pad worked. The open channels of the tray provide capillary action, which did not, in contrast to the pores of a pad, become blocked by air bubbles. Also, a tray dried quickly and there was little opportunity for any retained water to diffuse into the bottle in exchange for active liquid. In contrast the porous pad of the patented device retained liquid longer and permitted some diffusion. Also a tray was not as efficient in pulling liquid out of the bottle when dry as it was when wet.
44. I doubt whether the tray is an immaterial variant of a porous pad. But on the assumption that it is, I do not believe that that would have been obvious to the skilled addressee at the date of publication of the patent. Such a person is uninventive but is deemed to be possessed of common general knowledge: that is to say the knowledge which is common and general to designers of packaging articles such as the Toilet Duck. The skilled addressee would not have the knowledge of a skilled rheologist as suggested by the judge. That being so, there is no evidence to establish that the skilled addressee would see the tray as an immaterial variant.
45. It is unreal to consider infringement upon the assumption that the only difference between claim 1 and Mark II is the tray. The true position is that none of the features in the characterising part of the claim appear in the Mark II. To construe claim 1 to cover the Mark II would go far beyond fair protection to the patentee. The Mark II does not infringe.

Validity

46. The attack upon the validity of the patent was only to be advanced if the Court concluded there was infringement and the application to amend only arose if the patent was invalid. In the circumstances we did not ask Johnson Wax to develop the validity attack.

47. Conclusion

In my view the appeal should be dismissed and no order should be made on the respondents' notice.

LORD JUSTICE CHADWICK:

47. I agree that this appeal should be dismissed and that no order should be made on the respondent's cross appeal, for the reasons set out in the judgment of Lord Justice Aldous.
48. Put shortly – but not, I think, inaccurately or unfairly – the principal question raised by the appeal is whether, in the context of patent EP 0538 957, an impermeable shelf or plate in which there is a circular hole some 3 mm in diameter falls within the description "a liquid-permeable closure". In relation to that question there is no material difference between the Mark I and the Mark II version of the product said to infringe the patent.
49. In my view there is only one possible answer to that question. The shelf or plate is not, itself, liquid-permeable. The evidence before the judge established that the liquid can pass from the container through the hole and onto (or into) the porous pad without restriction or regulation. The reason why liquid does not do so unless in contact with the porous pad, as Lord Justice Aldous has pointed out, is that the hydrostatic pressure does not overcome the partial vacuum in the headspace of the container. A hole, through which liquid can pass without restriction or regulation, is not a closure; it is a conduit. Further, the passage of liquid through a such a conduit is not aptly described as a process of permeation. The liquid does not permeate through the hole; it flows through the hole. It is, in my view, an impermissible use of language to describe the combination of a non-permeable shelf or plate and a hole through which liquid can flow without restriction or regulation as "a liquid-permeable closure".
50. Nor am I persuaded either (i) that the variant which distinguishes the defendant's product (whether in the Mark I or the Mark II versions) from the apparatus which is the subject of the claim in the patent has no material effect upon the way in which the invention works; or (ii) that (if it does not) that would be obvious to the skilled addressee. I agree with Lord Justice Aldous that the appellant obtains no support from an approach based upon what has been described as the Protocol questions.
51. It follows that I, also, would hold that the claims for infringement have not been made out.

SIR MURRAY STUART-SMITH:

52. I agree.
Order: Appeal dismissed; appellants to pay the costs of the appeal, the cross-appeal and the application to adduce further evidence on the standard basis; permission to appeal to the House of Lords refused. (Order does not form part of the approved judgment)