[Home] [Databases] [World Law] [Multidatabase Search] [Help] [Feedback]
	England and Wales Court of Appeal (Civil Division) Decisions
You are here: BAILII >> Databases >> England and Wales Court of Appeal (Civil Division) Decisions >> Amersham Pharmacia Biotech AB v Amicon Ltd & Ors [2001] EWCA Civ 1042 (5 July 2001) URL: http://www.bailii.org/ew/cases/EWCA/Civ/2001/1042.html Cite as: [2001] EWCA Civ 1042, (2001) 24(12) IPD 24078

[New search] [Printable RTF version] [Help]

IN THE SUPREME COURT OF JUDICATURE
COURT OF APPEAL (CIVIL DIVISION)
ON APPEAL FROM CHANCERY DIVISION
MR JUSTICE LADDIE

		Royal Courts of Justice Strand, London, WC2A 2LL Thursday 5th July 2001

LORD JUSTICE ALDOUS:

1. The claimants, Amersham Pharmacia Biotech AB, appeal with leave of this Court against that part of the judgment of Laddie J of 26th October 2000 that held that patent no: GB 2258415, called the Chromaflow patent, had not been infringed. The respondents to this appeal, Amicon Limited, Millipore (UK) Limited and Millipore Corporation accepted that the alleged acts of infringement had taken place. At the trial they denied infringement and alleged that if infringement had been established, then the Chromaflow patent was invalid. In view of the conclusion reached by the judge, he made no finding on validity, but with leave of this Court the respondents filed a respondents' notice contending that, if infringement was proved, then the patent was invalid.

Infringement

2. The patent is entitled "Apparatus and method for charging and discharging of chromatography column beds". By way of introduction I adopt the judge's explanation of chromatography:

"4. … Chromatography is a process by which different molecules in a liquid carrier can be separated one from another. It is achieved by passing the liquid carrying the molecules through a column containing a matrix to the surface of which some of the molecules adhere, or which hinders the passage of molecules to different degrees. The result is that passing the liquid through the column splits up the different molecules into bands which then can come off the column at different times; thereby the contents of the liquid carrier are split into different fractions. This type of procedure is used in many industries, but it is used in particular in the pharmaceutical industry. Indeed, a well-known pharmaceutical company (Bayer) is one of the customers for the equipment which is in issue in these proceedings, and evidence was given in relation to sales to that company. A conventional structure for a chromatography separating column consists of a vertical cylinder containing the separating matrix. The mixture is added to the top of the matrix in the cylinder and it is eluted from the bottom, normally under pressure. These columns have grown in size over time. There are different types of matrix and there are different types of chromatography process. As far as the latter is concerned, some are conducted at very high pressures. As far as matrices are concerned, they can be made of differing types of material. For example, fine particles of certain resins are used in some chromatography columns.

5. The contents of the column must be very evenly and carefully loaded into the cylinder. This is a process referred to in the art as "packing". Over time, matrix media deteriorate and they need to be removed. Sometimes the media can be taken out and recycled and used again. In the art the process of removing media from the cylinder is called "unpacking". Until the end of the 1980s, there were two main ways of unpacking a chromatography column. The first was to lift the lid off the cylinder and to scoop out the contents either with a shovel or by washing it out with water jets. This was not hygienic and, for that reason, was not terribly desirable, particularly since, as I have said, one of the important uses for these columns is in the pharmaceutical industry. Secondly, with the growth in size of chromatography columns, the lid became progressively more heavy and it was burdensome having to lift it off for the purpose of removing the spent matrix. As a result, the second method was to push the contents out rather as a piston could push out the contents of a cylinder. All of this is common general knowledge and can be taken as background to the issues in this case."

3. The judge referred in paragraph 5 of his judgment to what was known "until the end of the 1980's". Nothing material occurred from then until the priority date of the patent . It follows that his findings as to the common general knowledge are relevant to construction of the specification which has a priority date of 8th August 1991.
4. I will come back to the parts of the specification relied on by the parties to support their cases on infringement, but will first explain the issue between them, using the description in the Chromaflow patent and a description of the alleged infringement. To do that I cannot do better than reproduce the appropriate passages from the judgment:

"12. …... The invention is described by reference to one preferred embodiment, which is illustrated in a number of drawings. Figures 1 and 3 are particularly significant for this part of the judgment.

Chromaflow Figure 1:



13. This shows a general arrangement drawing of a chromatography column. The so-called dispersion section, that is the section which can be used for adding the matrix to the cylinder and for dispersion of the liquid to be separated, is shown at the top half of the drawing in the area marked 10. The collection section is shown at the bottom and that is the area through which the eluted fluids come out and which can be used in the manner set out later described in the specification for removing spent matrix.

Chromaflow Figure 3:



14. This is a drawing of the collection section. It functions as follows. There is a metal plate (26) which is called the plunger head at the bottom of the cylinder. Above it is what is called a collection plate (78). Above that and distanced from the collection plate is a support grid (80), on top of which is a filter (82). In normal operation the eluted fluids pass through the filter supported on the support grid into the space above the collection plate. They then pass down a channel (94) to an outlet conduit which is shown on the left-hand side marked (86). In the centre of the collection plate there is a hole which is where the passage (94) for the outflow of the eluted fluids is located. This centrally located hole contains with it the end of a device which is central to the invention. This device passes through the hole in the collection plate and plunger head and through similar holes in the filter and support grid. It has a conduit (90) within it. Within that conduit there is a rod (108) which passes up through the conduit to a top part (112). This is described, as we will see in a moment, as a "probe". The bottom end of this rod is held in a rod support body (102) by a plug member (106) to which is attached a handle (110). By operation of the handle and the plug member -- the latter has a screw thread on it -- the rod can be made to move up and down. As illustrated in Figure 3 in solid line it is in its down position, in which location the probe head is pulled back firmly into the end of the cylindrical device which constitutes the conduit and is sealed in position by a gasket (122). However, operation of the handle (110) and thereby the plug member (106) results in the rod being advanced in an upward direction and it can take up the position shown in broken lines in Figure 3. When that happens, fluid and, as we shall see, spent matrix, can pass round the probe down beside the rod, through the central conduit (90) and down through a media outlet port (100) on the right. I should also mention, because it becomes important later, that the rod itself contains a conduit within it which is connected by way of a valve (116) and which leads from the valve up through the rod into the base of the probe. Fluid can be made to flow up that conduit and out through apertures (114) in the probe. As I will explain in a moment, the figure shows these apertures in what is clearly the wrong location. Nevertheless, for present purposes it is enough to say that fluid can be made to flow up the conduit within the rod out through the probe and into the area in which the matrix is located. One other point should be mentioned. The rod itself sometimes has holes along its length which are used to create a venturi effect, thereby assisting in the passage of spent media down the conduit and around the rod when the rod is in its elevated position. This can be used to flush spent media out of the column.

15. As I have said, the apertures (114) are incorrectly located on Figure 3. They are spray apertures and are shown on the top of the probe. If those spray apertures were where they are shown, they would be in constant communication with the flow passage (107) within the conduit and because, in many cases, there are venturi holes in that flow passage, there would be constant leakage from the base of the matrix, bypassing the filter and out into the media outlet. This is not consistent with the description which can be found at page 11 of the specification:

"During the separation run as aforesaid, the product and the before liquid are separately removed through the outlet tube 86. During this period the probe is sealed by a gasket 122 within the securing nut 120 which there acts as a probe sealing member so that all of the product and buffer flows through the filter 82, and through the holes 94 in the plate 78 and out the conduit 86."

16. Furthermore, the bottom section is described on page 9 of the specification as follows:

"The collection section 16 is similar to the dispersion section 14 (i.e. the top section) except that the order of parts is reversed."

17. Therefore it is equivalent to the type of arrangement shown in Figure 2 of the Chromaflow patent which is the illustration of the nozzle arrangement at the top of the cylinder.

Chromaflow Figure 2:



18. This is described on page 8 of the specification as follows:

"Disposed within the bore 66 of the tube 64 is an elongated hollow spray nozzle body 68 having a nozzle head 70 at the lower end 71 and comprising a plurality of oval shaped apertures 72 disposed about the periphery and having the lower end closed, the upper end 74 of the nozzle body being connected to a slurry media supply line (not illustrated)."

And at page 9 as follows:

"Prior to the separation and purification run the clamp 76 is loosened and the nozzle body 68 is drawn upwardly until the surface of the lower end 71 of the nozzle body is at substantially the same level as the opening in the nut 56. At this location the bore 57 is sealed and the nozzle body is again clamped. The separation and purification run may then be commenced by feeding product and buffer liquid through the inlet conduit 62."

19. Therefore this shows an arrangement in which the apertures on the top device are sealed completely when the nozzle tube is retracted from the position at which it protrudes into the media. To this extent the bottom arrangement and the top arrangement are consistent in that, in their respective withdrawn conditions, the apertures through which fluid can pass in the nozzle, or probe, as the case may be, are sealed off. This was the subject of cross-examination and the witnesses also agree that in both cases the apertures must seal and must be sealed closed in the retracted condition."

5. The respondents' device, called the Isopak was marketed in two forms. The Mark I is no longer on the market, but there is no material difference between it and the Mark II. They were described by the judge as follows:

"22. …. I can now turn to consider the defendants' devices. There is, for this purpose, no difference between them and I can refer to the illustrations provided by the parties.

Defendants' Product Figure 2:



23. This shows the collection plate (5), the filter support grid (6). It also shows an upstanding rod or nozzle system (items 9 to 12). This is locked in position. That is to say it is stationary with regard to the collection plate (5). That locking can be seen towards the bottom of the figure where there are two retaining bolts shown just on either side of the conduit leading up through the middle of the fixed nozzle. Thus the nozzle is fixed. It has a cap on the top (9) and it has laterally facing outlet ports (A) which are in communication with the central conduit (12). Around it there is a movable sleeve (8) which is shown in orange on the drawing as supplied by the parties. That slides up and down as can be seen by comparing this figure with the second view of the defendants' product set out below:

Defendants' Product Figure 4:



24. As I say, the actual nozzle or rod arrangement is stationary. It cannot be advanced into the medium and it cannot be withdrawn from it, except of course when the whole of the apparatus is disassembled. It is not designed or intended to be moved."

6. As appears from the descriptions of the device of the Chromaflow patent and the Isopak, the crucial difference between them is the way that unpacking occurs. In the Chromaflow patent a probe (112), moved by a handle, moves up and down. When down its head plugs the outlet bore. When up, it penetrates the medium and opens the outlet bore. There follows unpacking with the aid of buffer solution pumped through the radially directed spray openings in the head of the probe. In the Isopak, the rod (9-12) is stationary. The bore and spray openings are opened and closed by downward and upward movement respectively of the sleeve (8).
7. Claim 1 of the Chromaflow patent, split for convenience into integers, is as follows:

"(1) A chromatography column

(2) comprising a substantially cylindrical hollow housing for retaining a media bed through which a mixture to be separated into component substances and a buffer liquid may percolate,

(3) said housing having an axis of elongation disposed substantially vertically,

(4) a dispersion section at the top of said housing including dispersion means for receiving and dispersing said mixture and said buffer uniformly down into said media bed,

(5) and a collection section at the bottom of said housing,

(6) said collection section including a collector plate having passage means through which said component substances and buffer liquid may flow from said housing,

(7) an outlet manifold communicating with said passage means for receiving said component substances and said buffer liquid,

(8) said manifold having an outlet board for egress of said component substances and said buffer,

(9) a passage way extending through said plate and opening into said housing,

(10) a conduit communicating with said passageway for receiving spent media when said passage way is open,

(11) a media outlet port communicating with said conduit for egress of said media from said column,

(12) a rod having an internal flow passage extending through said conduit,

(13) a probe disposed on a distal end of said rod and having at least one aperture therein communicating with said internal flow passage of said rod,

(14) said probe being disposed within said passage way and configured to close said passageway,

(15) means for moving said rod relative to said conduit to dispose said probe in closing relationship with said bore [passageway] and to drive said probe into said housing selectively,

(16) and means for feeding liquid through said internal flow passage and out said aperture when said probe is disposed within said housing so that said liquid may loosen said spent media within said housing and carry said media through said passageway into said conduit and out said media outlet port."

8. It is clear and accepted by the appellants that claim 1 cannot be read onto the Isopak. The Isopak, even if it has a probe (integer (13)), which is "configured to close said passageway" (integer (14)), does not have the features of integer (15). There is no means for moving the probe in the manner required by this integer.
9. The submission of the appellants was that literal construction of patent claims is outlawed by the Protocol on the Interpretation of Article 69 of the EPC which is incorporated into our law by section 125 of the Patents Act 1977. They submitted that to provide fair protection for the patentee, the claims should be construed to cover the immaterial variant, used in the Isopak, of having a probe already situated in the housing with a moveable sleeve to open and shut the bore and apertures.
10. Section 125(1) of the Act states that the invention is that specified in the claims "as interpreted by the description and any drawings contained in that specification, and the extent of protection conferred by a patent or application for a patent shall be determined accordingly." Subsection (3) applies the Protocol. That states:

"Article 69 shall not be interpreted in the sense that the extent of the protection conferred by a European patent is to be understood as that defined by the strict and literal meaning of the wording used in the claims, the description and the drawings being employed only for the purpose of resolving an ambiguity found in the claims. Neither should it be interpreted in the sense that the claims serve only as a guideline and that the actual protection conferred may extend to what, from a consideration of the description and the drawings by a person skilled in the art, the patentee had contemplated. On the contrary it is to be interpreted as defining a position between these extremes which combines a fair protection for the patentee with a reasonable degree of certainty for third parties."

11. It is clear both from the terms of section 125(1) and the Protocol that the task of the court is interpretation. Further, the court has to take account not only of the words of the claim, but also the description in the specification. It is for that reason that the respondents and the judge relied on a number of passages in the description.
12. The judge set out the appellant's submissions in paragraph 26 of the judgment:

"26. .... I can pick it [the submission of the claimants]up in the skeleton produced by Mr. Carr QC who represents the claimants. At paragraph 31 he writes:

"Amersham submit that the relative movement is required to achieve two different states for the probe: closed and open. In the closed state, the passageway in the conduit is blocked off, as are the apertures in the probe. The open state enables feature 16 to be carried out, i.e. liquid passes out of the aperture in the probe to loosen the media, which is then carried out through the open passageway between the probe and the conduit. "32. Since there is relative movement, it does not matter whether the rod or the conduit move. Either will achieve the purpose. …There is no requirement in claim 1 that the probe should chip away or disrupt the bed."

And

"Puncturing and chopping is only described in the specific embodiment of the Patent, and is nowhere mentioned in the general description of the objects of the invention."

13. The judge rejected those submissions. He said:

"27. In my view these submissions are quite untenable. It is to be remembered that in the introduction to the patent, for better or for worse, the patentee having pointed out as the first problem that the spent media hardens, then says at page 3 that the hardened slurry dense mass must be broken up by chipping and the like and removed from the column. The first objective of the invention is said to be to provide a better means for removing the media after it is spent. In my view, the whole teaching of the specification is that the invention is designed to overcome the defect, or the problem, created by the existence of hard media when the chromatography column has been used. That is why the probe is there and why it is moved into and out of the cylinder. It will be recalled that Mr. Carr says in his skeleton that since there is relative movement it does not matter whether the rod or the conduit move. Either will achieve the purpose.

…."

14. The judge went on to set out a passage from the evidence of Mr Lu, an expert witness called by the appellants. He continued:

"28. That passage I find surprising because what it amounts to is a suggestion by Mr. Lu that what the inventor describes as the purpose of the probe is in fact not just unnecessary but should not be performed. Even if it is true that nobody in the art would want to chip and break away spent media, it is of no value having an expert saying that the patentee got it wrong. What the patentee says he was doing is clear. Mr. Lu does not think it was necessary. It may well mean that having a movable probe was not necessary either. But it is not possible to reinterpret the patent on the basis that one expert says that he does not think that the problem addressed by the invention is not a problem at all or that the method of addressing it is unhelpful. In any event, this evidence, which was based upon the thesis that spent media never needs to be chipped or broken up because it is always so soft that it can be simply washed out, seemed to me to be abandoned by Mr. Lu under cross-examination when prior art was put to him which referred to spent media sometimes being as hard as stone.

29. It follows that I do not accept Mr. Lu's evidence in so far as it suggested that spent media is never hard and never needs to be broken up; and in any event, for the reasons I have given, I do not think it is an answer to say that having a movable probe is unnecessary. On the contrary, if, as Mr. Lu says, it is odd to have a probe which tries to break up the spent media, it makes it all the more noticeable that that is precisely what the patentee here has chosen to describe and to direct his invention towards. In my view, there is nothing surprising or inconsistent or confusing about the disclosure of this specification. It explains the problem it is seeking to overcome, that is the existence of hard medium, and it explains clearly how it is going to do it, namely by using the probe to break up the hard media by advancing it into the media at the beginning of the unpacking stage."

15. Mr Carr QC, counsel for the appellants, criticised that part of the judge's judgment. He submitted that the judge had misread the specification. He submitted that the judge had taken the passage on page 3 of the specification which referred to breaking up the dense mass by chipping as referring to the invention and from that had concluded that the purpose of moving the probe was chipping. That conclusion, he submitted, was wrong. The passage on page 3 was referring to the prior art. The aim or purpose of the invention was to remove the spent media easily and without disassembly. The probe as claimed was not capable of chipping the spent media and the judge had failed to realise that claim 1 was not limited to use of the probe to puncture and chip spent media. That was the subject of claim 3. Further integer (16) of claim 1 emphasised that it was the means which fed the liquid which caused the unpacking. The purpose of the invention, claimed in claim 1, was to achieve the objects stated on pages 3 and 4 of the specification. The means of integer (15) was required to achieve two different states for the probe, closed and open. In the closed state, the passageway in the conduit was blocked off. The open state enabled integer (16) to be effective.
16. Mr Floyd QC who appeared for the respondents submitted that the judge's understanding of the specification was correct. Integer (15) of claim 1 could not be classified as an inessential element of the claim. To the contrary, it was the integer which identified the part of the apparatus which could deal with the problem that the invention was designed to be able to cure.
17. With those submissions in mind I turn back to the specification. It opens by explaining how in chromatography components of a mixture of chemical substances are separated by percolation of fluid through a bed of material. The solution of substances to be separated becomes the moving phase which passes through the continuous phase which is in the form of a gel or slurry. The specification states (page 1 line 30):

"As aforesaid the media of the continuous phase is a very fine particular slurry or gel initially, but after it has been used for some time it hardens and loses its effectiveness and becomes a dense mass. This spent media must then be removed from the column and replaced in the column with a fresh supply, i.e., the column must be repacked."

18. The specification then explains how the known prior art columns are packed and unpacked. It concludes (page 3 line 5):

"In that method, as with most of the other prior art proposals discussed in the aforesaid patent, the top of the column must be disconnected in order to charge or pack the bed and must then thereafter be reassembled.

As aforesaid, after the column has been in use for a time, the fine particle slurry gradually hardens into a dense mass. When this occurs the bed loses its effectiveness and thereafter must be removed from the column. The removal of spent slurry in the prior art requires that the bottom of the column be opened and that the plunger-like assemblies be disconnected from the cylindrical housing. Thereafter the hardened slurry dense mass must be broken up by chopping [chipping] and the like and removed from the column. The time required to move this spent slurry, the re-assembly of the bottom plunger-like assembly to the housing, the recharging of the housing and the re-assembly of the top plunger-like assembly is relatively substantial. In fact, the life of the bed during separation and purification of production runs may be no greater than the maintenance time required for the removal of the spent bed and the recharging of the column. Clearly, if less time is required to remove the spent slurry and recharge the column, production costs for the process may be substantially reduced."

19. The specification goes on at page 3 line 31 to set out these three objects.

"Accordingly, it is a primary object of the present invention to provide a method and apparatus for substantially reducing the amount of time for charging the bed media of a chromatography column and for removing the media after it is spent.

It is another object of the present invention to provide a method and apparatus which permits removal of spent slurry or bed media from a chromatography column and recharging of the column with fresh slurry without disassembling the column.

It is a further object of the present invention to provide a chromatography column having a packing valve assembly for charging the column with bed media and a dump valve assembly for removing spent bed media, without requiring the column to be disassembled."

20. There follows the consistory clauses in the form of the claims and then the description of the preferred embodiment. The only relevant part of that description is that which describes the movement of the probe. At page 11 line 7 it is said that during the separation period the probe is sealed by the gasket (122) so that all of the product in the buffer flows through the filter (82) and through the holes (94) in the plate and out of the conduit (86). It continues:

"After the media 55 has been used for a period of time and becomes spent, the plug 106 is rotated by means of the handle 110 to drive the rod 108 upwardly so as to drive the probe 112 into the housing 12. If the media has solidified the pointed probe will puncture and chip it as the probe forcibly enters the housing."

21. The only other relevant parts of the specification are claims 3 and 9 which are as follows:

"3. A chromatography column as claimed in claim 1 or 2, wherein said probe includes a pointed end remote from said rod for puncturing and chipping contacted media which may have hardened.

….

9. A method for replacing the media bed in a chromatography column through which a mixture to be separated into component substances and a buffer liquid may percolate from a dispensing section to a collection section without requiring disassembly of said column, said method comprising opening a port in the collection section to communicate the interior of said column with a media outlet conduit, driving a movable probe through said port and into the column to puncture and chip hardened media, pumping fluid through said probe into said column to loosen and liquefy said media so that said media may flow through said port to said outlet conduit, and filling said column with fresh media at the dispersion section."

22. Whether or not it be correct, the specification on page 1 makes it clear that, after use, the spent media hardens and becomes a dense mass. It goes on to describe the disadvantages of the prior art proposals and again draws attention to the patentee's belief that the media of the continuous phase hardens after use into a dense mass which has to be removed. In the prior art that is achieved by removing the bottom of the column and then removing the spent hardened media by breaking it up by chipping and the like. All that is said to be time consuming. The specification reasons that if less time is required for removal of spent media, production costs can be reduced. The objects of the invention are to reduce the time required to unpack the prior art devices and to enable removal of the spent media without disassembly and to do the same when repacking. The specification then states that the invention provides a chromatography column with the integers of claim 1.
23. I do not read the specification as suggesting that the objects of the invention cannot be achieved without chipping the dense media. However the specification makes it clear that the apparatus of the invention will need to deal with spent media which has hardened to a state where "chipping and the like" had in the past been required for removal. It follows that claim 1 has to be construed against that background.
24. Mr Carr submitted that integer (15) when properly construed could be written as follows:

"(15). means for moving said rod relative to said conduit [or said conduit relative to said rod] to dispose said probe [or conduit] in closing relationships with said bore and to drive said probe into said housing selectively [or to retract said conduit out of said housing]."

Integer (15), as set out above, is not intended to demonstrate the art of claim drafting as I suspect it would need to be written with an alternative which required a stationary probe to be within the housing with a moveable sleeve to open and close the bore. Its purpose is to illustrate the sort of change in language that would be needed to cover the Isopak apparatus. Despite that change, Mr Carr submitted that the Isopak arrangement of a stationary probe and moving sleeve was an obviously immaterial variant which the skilled reader would not have thought would be excluded by the words of integer (15). He submitted that to construe the claim in that way provided fair protection for the patentee and a reasonable degree of certainty for third parties as required by the Protocol.

25. In Wheatley v Drillsafe Ltd [2001] RPC 133, this Court explained the correct approach to construction. At page 141 I said:

"19. …. The Protocol outlaws what can be termed strict literal and also liberal interpretation using the claims as a guideline. The correct approach is to achieve a position between those extremes "which combines a fair protection for the patentee with a reasonable degree of certainty for third parties."

20. Strict literal interpretation using the drawings and specification gives to third parties the most certainty. That has always been seen as being unfair to inventors and of course is outlawed by the Protocol. However there must be a reasonable degree of certainty for third parties and therefore the language of the claim as interpreted in the light of the drawings and specification cannot be disregarded. As pointed out by Hoffmann LJ in Société Technique de Pulversatur STEP v Emson Europe Ltd [1993] RPC 513 at 522 an integer of a claim cannot be just struck out because it does not make any difference to the inventive concept. It may have been inserted by the patentee for some reason.

21. So far as the patentee is concerned it is important that the claim should be interpreted in accordance with his intention. A claim interpreted on the one hand too liberally can render the patent invalid and on the other too literally can allow third parties to avoid the monopoly.

22. The object of interpretation is to ascertain the intention of the author, in this case the patentee. This involves examining the words of the claim through the eyes of a person to whom the specification is directed, in the context of the specification as a whole. If the reader skilled in the art would have understood that the patentee intended that the claim should have a particular ambit, then to construe it as not confined to that ambit, by either strict or liberal construction, would be unfair to the patentee. It is the patentee that chooses the words and to widen the ambit contrary to his intention could invalidate the patent and to restrict the ambit could allow use of the invention without payment.

23. As the task of the court is to ascertain objectively what meaning the words were intended to convey, the Improver questions, better called the Protocol questions, were proposed as an aid. It is reasonable to infer, absent express words to the contrary, that the patentee intended to include within his monopoly what can be termed immaterial variants, in the sense that they were not material to the way the invention worked. Also it is reasonable to infer that a patentee did not intend to include within the ambit of his monopoly a variant which had a material effect upon the way the invention worked, otherwise his claims could, to the detriment of the patentee, include variants which had little if anything to do with what he had invented. However third parties have to be considered and therefore they should not be held to infringe if it was clear that such a variant was not intended to be within the ambit of the monopoly either because of the words chosen or because it would be seen to have materially affected the way the invention worked.

24. In Improver Corporation v Remington Consumer Products Limited [1990] FSR 181 Hoffmann J suggested at page 189 that the court when applying the Protocol should ask these questions:

"(1) Does the variant have a material effect upon the way the invention works? If yes, the variant is outside the claim. If no-

(2) Would this (i.e. that the variant had no material effect) have been obvious at the date of the publication of the patent to a reader skilled in the art. If no, the variant is outside the claim. If yes -

(3) Would the reader skilled in the art nevertheless have understood from the language of the claim that the patentee intended that strict compliance with the primary meaning was an essential requirement of the invention. If yes, the variant is outside the claim.

On the other hand, a negative answer to the last question would lead to the conclusion that the patentee was intending the word or phrase to have not a literal but a figurative meaning (the figure being a form of synecdoche or metonymy) denoting a class of things which included the variant and the literal meaning, the latter meaning, the latter being perhaps the most perfect, best-known or striking example of the class."

Hoffmann J went on to explain that the first two questions involved considerations of fact, but the last was a question of construction.

25. These questions do assist the court to construe a claim in accordance with the Protocol. Question 1 envisages that the claim has an ambit wider than the literal meaning of the words so as to give fair protection for the patentee; but that is subject to the safeguards contained in it when considered with question 2. Question 3 also provides a fair result for the patentee, namely avoidance of an unintended meaning. It also requires attention to the purpose of the words thereby giving fair protection for third parties.

26. As Hoffmann J pointed out at page 191, the answer to the first question depends upon the level of generality at which one describes the way the invention works. He said at page 192 "that the right approach is to describe the working of the invention at the level of generality with which it is described in the claim of the patent". I agree."

26. The judge concluded that the decision was so clear that it was not really necessary to consider the Protocol questions. However he did so briefly in paragraph 30 of his judgment:

"30. In my view, this is so clear that one really hardly needs to consider the so-called protocol questions. Nevertheless, it appears to me that even if the questions are asked, the answers are self-apparent. First of all: does the defendants' variant affect the way the invention works? Of course it does. In the defendants' device, there is no probe which advances into or out of the medium. It is, as I have said, stationary. Therefore, there is no possibility of it tackling the precise problem which the patent in suit was designed to overcome. Second: would this have been obvious to the skilled reader? Of course it is obvious. In my view, it is hardly arguable to the contrary. Third: would strict compliance be understood to be required? In my view, again it is really hardly arguable to the contrary. It is apparent that in the Chromaflow patent advancement of the probe is crucial, not an unnecessary and irrelevant addition to the device."

27. Mr Carr criticised the judge's approach to the questions and his conclusion. First, he submitted that the problem that the judge had in mind was not that stated in the specification. The stated objects of the invention did not refer to movement of the probe to break up hard spent media. The only reference to such use appeared on page 11 of the specification which was part of the description of the specific embodiment. Mr Carr also criticised the judge for not referring to the evidence which he submitted established that the difference between use of a moving probe and a stationary one, as in the Isopak, was minimal. He drew attention to claim 1 which does not require any particular size or shape of probe nor any amount of probe movement. It followed, he submitted, that the claim covered probes which could not tackle the problem, seen by the judge, by chipping the spent media. He also drew attention to claim 3 which required the probe to be pointed and suitable for puncturing and chipping. As claim 1 must be wider in scope than that claimed in claim 3, it by inference covered probes which were not designed to puncture and chip.
28. Mr Carr went on to draw attention to the need to describe the working of the invention at the level of generality with which it was described in claim 1. He submitted the way the invention worked could not, when described at the appropriate generality, be taken to require an apparatus which would carry out significant chipping of spent media. If so, the variant used in the Isopak had no material effect upon the way the invention worked and that would have been obvious to the skilled reader.
29. Mr Floyd submitted that the judge was right to conclude that there was a material difference between moving a probe in and out and having the probe stationary and moving a sleeve in and out. That was evident because the probe when advanced displaced spent media. That did not occur with the Isopak arrangement. Secondly, in the Isopak the presence of the probe in the column during separation caused difficulties by providing a region of inhomogeneity which could affect the performance of the column. It followed that there was a material effect in the way the Isopak worked when compared with the invention claimed in claim 1.
30. The evidence did not establish that there was a difference in practice, as opposed to a theoretical one, when using a moving probe as opposed to the stationary probe of the Isopak. Mr Johnson, an expert called by the respondents, did not believe that there was a technical reason for having a moving probe instead of a stationary one. He also believed that because the Isopak probe was small, compared with the size of the column, it would not affect performance. He accepted that upward movement of the probe would disrupt the spent media, but said the amount would be minimal. The purpose of moving the probe up was "to get the fluid impinging into the area of the column that you would want to access." At page 107 of Evidence 1 he was asked:

"Q. Now imagine the case where the sleeve is retracted, pulled down and

creates a void, again either the material will crumble into the void or the buffer will come up and fill the void and thereby assist in the slurry, will it not?

A. Since that void is part of the conduit, part of the fluid path way to exit the

column, yes. That is the idea.

Q. Can you see any material difference between the two cases?

A. I think I already stated, I think that they would function properly and they

would both be effective at trying to accomplish what they were trying to accomplish, yes."

31. Mr Lu, the appellant's expert, did not believe that the Isopak probe introduced inhomogeneity. He accepted that there were differences between the Chromaflow arrangement and that of the Isopak. He did not know whether movement of the sleeve in the Isopak would disturb the spent media, but conjectured that it would.
32. It does not need evidence to realise that there is a difference between moving a probe into spent media and the Isopak arrangement whereby the probe remains stationary with the sleeve moving down. However the evidence is consistent with there being no material difference between the two systems when they are carried out, in the sense that they produce the same result, but with a different mechanism. They show different ways that can produce an equivalent result.
33. I do not believe that the Protocol introduced into our law a doctrine of infringement by equivalent effect by use of a different mechanism. That may be for the future. But at the moment the task of the Court is to construe the claim as part of the whole specification. Further the requirements of the Protocol do not mean that an integer can be treated as struck out (Step v Emson Europe Ltd [1993] RPC 513 at 522). Claim 1 is for an apparatus and therefore the first two protocol questions must consider the way that the apparatus is constructed. Integer (15) requires there to be means for moving a rod to move a probe in and out. That is the way that the claimed apparatus works. The Isopak arrangement is materially different. There is no movement of the probe. The fact that it produces an equivalent result does not enable the first two protocol questions to be answered in the negative.
34. In any case I believe the judge was right to conclude that the skilled reader would have understood that the patentee intended that integer (15) should limit his monopoly to probes which moved in and out of the column. That much appears when the claim is read in the context of the specification. The problem which the invention was said to solve was the need to avoid removing the bottom of the cylindrical housing and then removing the hardened spent media by chipping and the like. That was overcome by an apparatus with the components of integers (8) to (16) of claim 1. The patentee contemplated that the means which moved the probe would drive the probe into the housing. The purpose was to make sure the probe moved into the hardened spent media which was the only way the patentee contemplated that the spent media could be flushed out.
35. To construe integer (15) as covering the Isopak, necessitates disregarding the words of that integer. That approach is outlawed by the Protocol which requires a reasonable degree of certainty for third parties. If the words of integer (15) are to be construed as covering what is said to be an equivalent mechanism, namely the Isopak, then I can see no reason why the integer should not cover other equivalent constructions not envisaged by the patentee. In fact the mechanism of the Isopak is essentially different to that claimed. The patentee chooses the words with which to define his invention. Third parties should be able to discern, from the terms of the patent, which equivalent mechanisms, if any, are included in the claim.

Validity

36. The judge did not give his views on the validity attack as they were only pressed, if he decided there was infringement. But as they were fully argued before us, I will deal with them shortly.
37. Added Matter - The respondents contended that if the patent as granted was construed as covering an invention which included the Isopak, then it was invalid because "the matter disclosed in the specification of the patent extends beyond that disclosed in the application for the patent, as filed ….". (See section 72(1)(d) of the Patents Act 1977).
38. The basis for that submission was the form of the application. It is for all material purposes identical both in description and claims to that of the patent, save that in the specification of the granted patent the paragraph which appears after the three objects, set out at page 3 line 31, is in the form of claim 1, whereas in the application it states:

"Accordingly, the present invention provides a chromatography column having a media and product inlet assembly positioned at the inlet of the plunger-like assembly at the top of the column, the media and product inlet assembly including a housing having a product/buffer inlet passage and a dump valve assembly at the plunger-like assembly at the bottom of the column, the dump valve assembly including a hollow rod extending concentrically through a discharge conduit through which spent media may flow, the rod being selectively movable through the collector section including the collector plate and into the column, and having a probe at the upper end for puncturing and chipping the spent hardened media. Liquid, such as the buffer liquid, may be pumped through the hollow of the rod and out apertures in the probe to loosen and liquefy the spent media which thereafter flows through the discharge conduit. Preferably the media discharge conduit is concentrically disposed within the product and buffer discharge passage at the outlet of the collector plate." (emphasis supplied)

39. Mr Floyd submitted that in the patent application it was made clear that the objects of the invention were achieved by the apparatus described in the passage quoted above. That required a probe suitable for puncturing and chipping spent hardened media. That being so, claim 1 in the patent application could not possibly be construed as covering the Isopak which did not have a movable probe. It followed that if claim 1 of the patent were to be construed as covering the Isopak that must be the result of the deletion of the above quoted paragraph in the application and the substitution of a paragraph in the terms of claim 1. That could only have been the result of matter being added by deletion of the above paragraph and substitution of a more general statement of what the invention was.
40. Mr Carr reminded us that it was permissible to widen the ambit of claims before grant. He submitted that there had not been any additional matter. All that had been done was to remove an inconsistency between the claim and the consistory clause.
41. In view of the conclusion reached on construction, it is clear that matter was not added. But I was not convinced that there was not substance in the submission of Mr Floyd.
42. Obviousness - The allegation of obviousness started from the supply of a column, called the Farmitalia, by Millepore (UK) Limited in October 1986. It had a mechanism which permitted the delicate task of packing to be carried out without removing the lid. This was achieved by admitting the media through a valve and packing it down with a plunger. Unpacking was achieved by undoing bolts to allow the bottom to drop down. The spent media was then removed by using the plunger to eject the spent media into a suitable container.
43. The case for the respondents went as follows. The Farmitalia showed how a valve could be used to avoid the disadvantage of having to remove the lid for packing. Once that had been shown to be practical, it was obvious to use a valve for the unpacking to avoid the need to remove the bottom plate. That being so, all the notional skilled person had to do was to make a patent search for a suitable valve. That would have produced US Patent No. 691975 (Schaaf) which disclosed a valve having all the relevant integers of claim 1 of the patent.
44. That case lacks any merit. Its existence depends upon knowledge of the invention. First there was no cogent evidence to support the contention that the packing arrangement of Farmitalia would have made it obvious to use a valve for unpacking. The problem existed when Farmitalia was produced and the makers of that column did not think of doing it, despite the time consuming work of unpacking that had been carried out for several years. That might have been due to inertia in the industry, but Dr Mann accepted in cross-examination that the introduction of Chromaflow with packing and unpacking in situ meant that the respondents had to address the problem that existed with prior art devices. Thus there appears to have been a need for in situ unpacking which was either not appreciated by Millipore or they had not thought of the solution.
45. Even if it was obvious to unpack using some sort of valve, I reject the submissions that it was obvious to adopt the information in Schaaf. Schaaf was filed in 1900 and was published in 1902. It relates to an invention for a paper pulp discharge valve. It was designed to deal with pulp sticking in conduits through which it passed during paper manufacture. The valve consists of a cone which seats to close the body. The cone can move into the pipe work to be cleaned thereby allowing liquid to be sprayed from perforations into the conduit. From that short description of the Schaaf disclosure, it is apparent that it is concerned with a different field to that of the patent. It is a very old patent and I can see no reason why anybody who had Farmitalia in mind would pause for a second if he read Schaaf, unless he had the invention in mind. That of course would not be a permissible approach. These comments from the judgment of Laddie J in Inhale Therapeutic Systems Inc v Quadraint Healthcare Plc (unreported, 20th June 2001) are pertinent:

"A fiction in patent law is that the notional uninventive skilled man in the art is deemed to have read and assimilated any piece of prior art pleaded by the party attacking the patent claim. If the invention is obvious to that person in the light of a particular piece of prior art, the claim is invalid. It is no answer to say that in real life the prior art would never have come to the attention of a worker in the field, for example because it was tucked away on the top shelf of a public library or because it was in a language which nobody in the art knew. The notional skilled person is assumed to have read and understood the contents of the prior art. However that does not mean that all prior art will be considered equally interesting. The notional skilled person is assumed to be interested in the field of technology covered by the patent in suit, but he is not assumed to know or suspect in advance of reading it that any particular piece of prior art has the answer to a problem he faces or is relevant to it. He comes to the prior art without any preconceptions and, in particular, without any expectation that it offers him a solution to any problem he has in mind. Some pieces of prior art will be much more interesting than others. A document directed at solving the particular problem at issue will be seized upon by the skilled addressee. Its very contents may suggest that it is a worthwhile starting point for further development. But the same may not be the case where a document comes, say, from a distant and unrelated field. For example, in theory a notional skilled person engaged in trying to improve the operation of an internal combustion engine is assumed to know, have read and assimilated the contents of all published material including those, say, in the baking field. It may be that a document in the latter field discloses something which, if applied to the internal combustion art, would produce a marked improvement in performance. However the person skilled in the art is not deemed to read the baking document in the knowledge, or even with a suspicion, that it is of significance to the problems he has to deal with. It may be that it is written in such a way that, although he understands it, the skilled person will dismiss it as irrelevant to his work. The more distant a prior art document is from the field of technology covered by the patent, the greater the chance that an intelligent but uninventive person skilled in the art will fail to make the jump to the solution found by the patentee."

The Schaaf patent is so old and so distant from the field of technology covered by the Chromaflow patent that I cannot see how the skilled person would add Schaaf to Farmitalia. The obviousness attack based on Schaaf was hopeless.

46. Mr Floyd also submitted that even if it was not obvious to use the information in Schaaf to alter the Farmitalia, there was no invention in modifying Farmitalia so as to carry out in situ unpacking with a valve as claimed in the claim. To support that case he relied on the evidence of Dr Mann. In July 1986 Dr Mann wrote a "Disclosure of Invention" to enable his employers to consider whether patent protection should be sought. In the end it was not, as it was considered that the prior art was too close to make that a useful exercise. The document contains a number of ideas; one has a central part at the bottom of the column to provide an exit for the spent media. It seems to contemplate in situ unpacking, but it was not worked up into a product before disclosure of the Chromaflow columns.
47. Dr Mann's "Disclosure of Invention" was not made public and therefore cannot be relied on as prior art. It is relied on as evidence that what was in the disclosure was obvious. As such it is not persuasive. Dr Mann must have believed it was an inventive idea for modification of Farmitalia as he submitted it as a "Disclosure of Invention". It is not possible to decide whether the decision not to patent was correct as the prior art taken into account was not placed before this Court. Further, Dr Mann's qualifications exceeded those of the notional skilled addressee.
48. I conclude that the attack of obviousness was not made out. In the result the appeal fails.

LADY JUSTICE HALE:

49. I agree.

LORD JUSTICE JONATHAN PARKER:

50. I agree.
ORDER: Appeal dismissed with costs; certificate of validity granted; permission to appeal to the House of Lords refused; appellants to pay seventy per cent of the respondent's costs, detailed assessment.
(Order does not form part of approved Judgment)