Corma Inc & Ors v Hegler Plastik GmbH & Anor

This is a summary judgment application brought by the defendants in the course of a patent dispute. The patent is EP (UK) 1 363 766 entitled “Method and device for producing a double-walled thermoplastic pipe with integral pipe bell”. The patent concerns a method of making plastic corrugated pipes. The defendants request that the claim for infringement be summarily determined. There were other ancillary applications before me but this judgment relates to the application for summary judgment. The claimants can be referred to collectively as Corma and the defendants as Hegler.

The infringement claim concerns a corrugator used for making corrugated pipes known as the “Hegler Device” and in particular the process that is used to make three sizes of pipes: the 375mm, 450mm and 600mm pipe sizes. Claim 1 of the patent is the only claim in issue and it covers a method for making such pipes. There is also a counterclaim by Hegler for revocation.

The action was commenced in August 2011 and the trial was due to take place in May 2013. Expert and factual evidence had been served and trial skeleton arguments exchanged. Just days before trial Hegler sought to introduce a new experiment which had been undertaken by their expert on the 375mm process. Helger said that this experiment proved non-infringement.

On the day before the trial was due to begin, Warren J allowed the evidence to be admitted and ordered that the trial be vacated to give Corma the opportunity to undertake infringement measurements and experiments in reply. The Judge ordered Hegler to permit further inspections and measurements to be undertaken on the three processes in issue. The trial has been relisted for January 2014 and Warren J left it to the parties to agree a timetable for the inspections and other matters to be undertaken.

Late in May 2013 the EPO Board of Appeal considered the validity of the patent over the same prior art as is in issue in these proceedings. The EPO decided that the claim as granted was invalid but that an amended claim was valid. The patent was therefore allowed by the EPO in an amended form. Helger’s position is that there is no real prospect of a finding of infringement on the amended claim and Hegler has now brought this application for summary judgment.

Mr Andrew Lykiardopolous appears for the claimants instructed by Powell Gilbert LLP and Mr Michael Silverleaf QC appears for the defendants instructed by Bristows LLP.

Having heard the argument I informed the parties that I would refuse the application for summary judgment. These are my reasons for that decision. There is no need for the parties to attend the handing down of this judgment.

There is no dispute about the principles applicable on an application for summary judgment of this kind. Mr Lykiardopolous referred to the summary by Kitchin J in Allen v Bloomsbury Publishing PLC[2010] EWHC 2560 (Ch) in paragraphs [11] to [13]. Among the judgments referred to in that passage are Three Rivers D.C. v Bank of England (No. 3)[2001] 2 All ER 513, Swain v Hillman[2001] All ER 91, ED & F Man Liquid Products v Patel [2003] EWHC (Civ) 472, Doncaster Pharmaceutical v The Bolton Pharmaceutical 100 Limited [2006] EWHC (Civ) 661, and Celador Productions v Melville[2004] EWHC 2362 (Ch). I will not set out Kitchin J’s summary of the law which was not challenged by Mr Silverleaf.

Mr Lykiardopolous also referred to Monsanto v Merck[2000] RPC 77 in which the Court of Appeal warned against construing a patent at a summary stage since that task can only be accomplished after a court has heard the evidence necessary to adopt the mantle of the person skilled in the art, and endorsed the approach of the Court of Appeal in Strix v Otter Controls[1991] FSR 354 in which Dillon LJ held that it had been wholly inappropriate for an infringement case to be struck out.

Mr Silverleaf reminded me of the judgment of the Court of Appeal in National Westminster Bank v Daniel[1993] 1 WLR 1453. In that case Glidewell LJ considered the proper test which the court should adopt on an application for summary judgment. Although it was a case under the former Rules of the Supreme Court Order 14, Mr Lykiardopolous did not suggest that the principles enunciated there were not applicable before me under the CPR. Glidewell LJ said the following at page 1457 at E:

Mr Lykiardopoulos did not suggest that this did not apply to the case before me and I accept Mr Silverleaf’s submission that it does.

Claim 1 of the patent is as follows:

a first tube is extruded into a mould tunnel comprising at least one row of moulds guided on a path,

the first tube is given a corrugated shape in at least one first section and expanded into a connecting sleeve in at least one second section,

a second tube is extruded into the first tube and pressed against the corrugation troughs of the first tube,

while the first tube is being given the corrugated shape and the second tube extruded into the first, a space (A) between the two tubes is subjected to a pressure p1 that is above atmospheric pressure,

the space (A) between the two tubes is subjected, at a specified time before or after expansion of the first tube into a connecting sleeve, to an essentially constant pressure p2≤p1, or to a variable, but not continuously declining pressure p2, p2 lying above atmospheric pressure,

during extrusion of the second tube into the first tube, which has already been expanded into a connecting sleeve, the second tube is internally subjected to a pressure p3 above atmospheric pressure and pressed against the first tube, and

pressure p1 is subsequently again applied to space (A) between the two tubes.”

Claim 1 is shown above in the form as amended in the EPO. The words struck through in feature 1(e) were present in the claim as granted and have been deleted as a result of the decision of the EPO Board of Appeal. It will be noted that feature 1(e) is now limited to a requirement that the pressure p2 in the space (A) at the relevant time is an essentially constant pressure which is less than or equal to the previous pressure in this region (p1) and is a pressure above atmospheric pressure. Before amendment, although p2 still had to be above atmospheric pressure, the claim also covered the case in which p2 was a variable, but not continuously declining, pressure. That possibility has been removed from the claim by the amendment.

The defendants’ case is put on two bases. The first is that on the facts which are undisputed it is submitted that the process operated by the Hegler Device on all three of the pipes does not infringe the claim in its form now amended. I can dismiss this basis of the application for summary judgment without any detailed consideration of it because the claimants’ infringement case is supported by the evidence of Professor Tim Osswald. Professor Osswald is a Professor in the Department of Mechanical Engineering at the University of Wisconsin in the Polymer Engineering Center. He has provided five expert reports in these proceedings. His fifth expert report articulates his opinion that the process operated by the Hegler Device satisfies the requirements of claim 1 of the patent in its form as amended by the EPO and in particular of feature 1(e).

Professor Osswald’s opinion in his fifth expert report is that the Hegler Device in operation satisfies the pressure requirements of integer 1(e). In particular he states his view that in the relevant space at the relevant time there is an essentially constant pressure which is less than p1 and is above atmospheric pressure. I should say that the defendants do not accept this opinion is correct but it is perfectly apparent that on this application there is no basis for saying that the claimants do not have a realistic prospect of success based on Professor Osswald’s opinion. That is sufficient to dispose of the first basis on which Mr Silverleaf puts his case.

The second, and I should say the real basis on which the defendants apply for summary judgment is the following. They say as a result of the way in which the Professor’s opinion has been expressed in his various reports and, in particular, as a result of the existence of a fundamental change in his position (as the defendants see it), the court is in a position today to say that Professor Osswald’s evidence as a whole is not credible. Mr Silverleaf submits that the court can and should conclude that Professor Osswald’s evidence is not credible. He contends that since Professor Osswald’s evidence as a whole taken across his reports is the only evidence which the claimants have to support their case of infringement; once the court has decided that Professor Osswald’s evidence is not credible, summary judgment should be given in the defendants’ favour. There is no other evidence to support the claimants’ case.

Mr Silverleaf recognises that to ask a court to find that an expert witness’s evidence is not credible at a summary stage without having heard the witness is a significant thing but, he submits, when the matters are looked into, the Professor’s evidence is incapable of being believed. The court can and, therefore, should find in the defendants’ favour.

Mr Lykiardopolous on the other hand submits that the court cannot decide on this application that Professor Osswald’s evidence is not credible and accordingly this element of the defendants’ application should be dismissed and so the application for summary judgment itself should be dismissed.

In order to understand the defendants’ application it is necessary to go into the detail of how the invention works and how the Hegler Device works.

As I mentioned above the case concerns methods of making twin walled corrugated plastic pipes. In particular it relates to making twin wall in-line connecting sleeves for those pipes. The connecting sleeves enable adjacent pipes to be fitted together with only a single join. The corrugated sections of pipe are made by extruding semi-molten plastic from an extrusion head located within a tunnel of moving mould blocks. The outer tube of plastic is expanded against the corrugations of the mould block by pressurised air acting from inside and/or a partial vacuum exerted though channels in the mould blocks. The inner tube is typically forced against the corrugations of the outer layer to which it welds by pressurised air acting from the inner side.

In-line connecting sleeves are manufactured by moulding them continuously with the corrugated sections and then cutting one end away. The in-line process makes use of discrete mould blocks having smooth walls and an internal diameter larger than that of the corrugated mouldings.

The diagrams annexed to this judgment are taken from the defendants’ skeleton argument and show the process of moulding the two walls of the pipe at the stage of the connecting sleeve.

In the diagrams the two thick lines are the two walls of the pipe. In the colour version of the diagrams the outer wall is shown in red and the inner wall in blue. The corrugated outer wall can be seen above the flat inner wall. The moulds move from left to right in the picture while the lower central block from which the two streams of plastic are extruded remains stationary. In the first diagram, as the moulds move to the right, the top stream makes a corrugated shape. Then in the second diagram the top stream begins to make the uncorrugated connecting sleeve part. In the third diagram the top stream has now made most of the connecting sleeve part and the lower stream of plastic is at the start of the connecting sleeve area. In the fourth diagram the lower, inner layer of plastic has started to be extruded against the inside surface of the outer layer of plastic at the connecting sleeve region. Also, the outer plastic layer has now begun to reach the corrugated moulds again to start making a new piece of corrugated pipe. In the fifth diagram the outer sleeve part has now made a number of corrugations and the inner layer is moving along forming the connecting sleeve. In the final diagram the inner layer has now finished forming the connecting sleeve part and begun to reach the part where the outer layer is corrugated. When the part is completed the connecting sleeve will be cut at the left hand end of the connecting sleeve area.

The issues relative to feature 1(e) of the Claim relate to the pressure of the air in the region between the two walls. That is the region called space (A) in claim 1. In the Hegler Device that region is always vented to the atmosphere through a thin pipe. At the stage of the first diagram, the region is supplied with compressed air. It is also still supplied with compressed air in the second diagram. The stage of the third diagram is referred to as a transition point and at this stage the compressed air supply to the region between the two tubes is switched off. The process continues and then at the sixth diagram the compressed air supply to the region between the two tubes is switched on again. The issue for the purposes of Claim 1(e) is: what happens to the air pressure in the region between the two tubes at steps 3, 4 and 5 of the diagram? Although the space is vented to the air it is clear that the vent hole, like other vent holes in the process, is very small and so it does not follow that the pressure in this region necessarily instantly falls to atmospheric pressure when the compressed air supply is switched off. I should say that, as I understand it, at least for the purposes of this application there is no dispute that when the region is connected to the compressed air supply, it is at a pressure which is higher than atmospheric pressure.

In his third and fourth expert reports which were provided before the amendments to the claim in the EPO, Professor Osswald gave evidence to support the claimants’ claim that the process infringed and in particular satisfied feature 1(e). Much of the evidence is based on inferences about what the pressure in space (A) must be. The inferences are drawn from trying to monitor the flow of air from the relevant vent nozzle as the process continues. In his third report Professor Osswald identified three disturbances in the air flow out of the vent nozzle in or around the relevant time.

The first disturbance is a rapid reduction in air flow at the point that the compressed air is switched off. It is common ground that before me on this application I do not need to be concerned with that rapid reduction in air flow. The claimants’ case is that the fact the air flow has reduced when the compressed air was switched off does not mean that the pressure in the space necessarily has changed. That is not a matter I have to decide on this application.

The second disturbance in the air flow which Professor Osswald observed is a series of fluctuations in the flow of the air which he observed during the time when the connecting sleeve part was being made. Professor Osswald thought there were two fluctuations and Professor Gibson, the expert witness giving evidence for the defendants, thought there were five. The number of fluctuations does not matter. It is common ground, however, that these fluctuations were indeed observed. Their significance is critical to the question of infringement as it now stands.

The third disturbance in the air flow observed by Professor Osswald was a further reduction which lasted for two to three seconds following which the rate of air flow increased to its original level once the compressed air supply was switched back on. This third disturbance in the air flow does not give rise to a substantive point that I can decide on the application for summary judgment. Although it is hard to see that the fluctuation could be described as evidence of essentially constant pressure, the claimants say that this disturbance is irrelevant because it relates to the step of making a piece of the connecting sleeve which will be cut off in practice and so does not matter. I cannot resolve that on this application.

That leaves the question of the second disturbance observed by Professor Osswald, consisting of two (or five) fluctuations. In his fourth report at paragraph 54 the Professor stated the following:

Also, at paragraph 67 of his fourth report, Professor Osswald said as follows:

The defendants submit that what the Professor was saying in his third and fourth reports was that the Hegler Device satisfied feature 1(e) on the basis that the element which was satisfied was the presence of a variable but not continuously declining pressure. The significance of this, of course, is that the amendments to the claim in the EPO mean that this element is no longer part of Claim 1. After the amendment occurred, in Professor Osswald’s fifth report, the Professor expresses the view that the pressure satisfies the element of feature 1(e) which remains in Claim 1, that is to say there is an essentially constant pressure which is less than or equal to the previous pressure.

Part of Mr Silverleaf’s submission is that it is simply incredible for the Professor to have changed his opinion in this way. Mr Silverleaf submits that the “essentially constant pressure” or “variable pressure” were clear, distinct alternatives in the claim, and the Professor's clear opinion was that the process satisfied one alternative and now that option has gone, he has changed his mind and this change of mind is not credible. Moreover says Mr Silverleaf, while a change of mind could be credible, in order for it to have any credibility it would need to be explained by the person in question, recognising that their view at one stage was one way and explaining why their opinion had changed. However, Mr Silverleaf submits that is not what Professor Osswald has done. The fifth report does not, says Mr Silverleaf, face up to the reality of his opinion in his third and fourth reports and denies that he ever did express the opinion that the pressure was variable beforehand.

Mr Silverleaf refers to paragraphs 30 and 32 of the Professor’s fifth report. Paragraph 30 refers to what the Professor said in paragraph 54 of his fourth report which I have already quoted, and paragraph 32 refers to what the Professor said in paragraph 67 of his fourth report which I have quoted above.

I will deal first with paragraph 32 and the reference to paragraph 67 of the fourth report. The point relates to the three disturbances in the air flow from the vent referred to above. Professor Osswald does not deny that the first and third disturbance may be regarded as sufficiently large so as not to fall within the ambit of the need for an “essentially constant pressure”. However the claimants contend those two disturbances are irrelevant. In paragraph 32 of his fifth report Professor Osswald explains that his agreement with Professor Gibson that the Hegler Device does not maintain an essentially constant pressure in the space between the layers for the duration of the formation of the connecting sleeve included the third disturbance. In other words it included the period of operation of the process which is longer than the relevant period which falls to be considered. I accept the claimants’ submission on this point. Paragraph 32 can be read in a way which reconciles paragraph 67 of the fourth report with the claimants’ infringement case as it is now articulated and supported by the fifth report of Professor Osswald. For the purposes of this application I do not accept that paragraph 32 allows me to conclude, without cross-examination, that the Professor’s evidence is not credible (NatWest Bank v Daniel).

The other part of Professor Osswald’s evidence, however, is more difficult. Paragraph 30 of his fifth report seeks to explain paragraph 54 of his fourth report (partially quoted above). Paragraph 30 says:

Mr Silverleaf submitted that this evidence in paragraph 30 was simply incredible. He submits that first of all the Professor admitted that there was a variable flow of air in paragraph 54 and given that he was equating the flow of air with pressure he quite obviously was admitting that there was a variable pressure. Mr Silverleaf then submits that the last sentence of paragraph 54, which makes the point that the pressure does not continuously decline, only makes sense if the Professor had been considering the feature which has been deleted from 1(e) of claim 1. Feature (e) of claim 1 distinguishes between two different pressures. One is an essentially constant pressure and the other is a variable but not continuously declining pressure. If the pressure had been essentially constant then being “not continuously declining” would have been irrelevant. The question of whether the pressure is continually declining is only relevant if the pressure is variable.

Thus, submits Mr Silverleaf, in the third and fourth reports the Professor’s evidence and the claimants’ case was that the pressure was variable but not continuously declining. Now the claimants’ case is that the pressure is essentially constant. If the claimants’ case had been that it was essentially constant there would have been no need to consider whether it was continuously declining.

The point of this submission is that although it might be said that small variations in pressure could be capable of falling within the ambit of an essentially constant pressure, (since after all adding the word essentially to the word constant could be said to allow for small variations in pressure and therefore be read in such a way as to mean that the claim was not limited to absolutely constant pressure), that was never what the claimants’ case was because otherwise the claimants would not have been concerned with the continuously declining pressure.

Mr Lykiardopolous submitted that this was wrong and that the Professor's evidence was, as he says in his fifth report, never on the basis that the pressure was variable rather than essentially constant, he had simply expressed a view that the pressure was not continuously declining.

I must say, if I take the Professor’s reports at face value, I believe they can be read in the manner proposed by Mr Silverleaf. Indeed, I am not at all sure that Professor Oswald’s explanation in his fifth report really faces up to the true scope of his evidence in the third and fourth reports. However, what I am sure about is that I cannot say on this application, on the summary basis and without having heard the Professor in the witness box, that his evidence lacks all credibility. No matter how much I may doubt that the Professor has faced up to the problems with his evidence I am quite satisfied that it would not be right for me to rule on a summary application that his evidence is so doubtful as to lack all credibility. For that reason I will not accede to the defendants’ application.

I should mention another one of the problems with the claimants’ evidence. The position they now take throws up the question of how big may fluctuations be which are within the ambit of the phrase “essentially constant pressure”. Professor Osswald in his fifth report says that the fact the pipes which have been made by the Hegler process are acceptable in terms of their physical properties, they have no banding and no areas of local thinning, means that fluctuations are not significant and therefore must be within the term ‘essentially constant’. At first sight that sounds superficially attractive but as the defendants point out it is difficult to see how that can be the determinant of which ‘essentially constant’ means because the patent as granted contemplated that a variable pressure, provided it was not continually declining, would produce satisfactory products. Thus, say the defendants, the fact that the pipe that is made is satisfactory cannot prove that the variations in pressure are so small that they must be within the scope of the term ‘essentially constant’. I can see considerable force in the defendants’ argument on this point and it does appear that the claimants’ case does not face up to the effect of the amendment in the EPO. However, again, I cannot resolve this matter on an application for summary judgment.

The defendants’ application is refused. The matter will go to trial.