Ipsofactoj.com: International Cases [2002] Part 2 Case 1 [Ch.D]





Trianco Redfyre Ltd


31JULY 2000


Mr Justice Pumfrey


  1. This is an action for infringement of UK Patent 2269656. The inventor and proprietor of the patent is Mr Jon Sapey. The invention in respect of a boiler. The alleged infringement is a wall mounted boiler manufactured by the Defendant ("Trianco") called the "Eurostar", which is alleged to infringe Claims 1, 3 and 10 of the patent in suit. The Defendant alleges that the patent is not infringed, and that it is invalid. The grounds of invalidity are

    • first, anticipation by prior use of a boiler called the Beta boiler manufactured by a company called Heating World;

    • second, obviousness in the light of this prior use and in the light of prior use of a boiler called the WallJet made by the Defendant, of a boiler called the CentraJet equally made by the Defendant, and a range of boilers made by Perkins Boilers Limited between 1968 and 1974.

    Finally, the Defendant relies upon its own patent 1,501,117 published on 15th February 1978.

  2. A particular issue arose in relation to the construction of the Beta boiler. This boiler was manufactured over a comparatively short period of time, but Trianco contended that it was manufactured in two versions, one only of which affected claim 3 of the patent, and it was necessary to consider the evidence both of Mr Bosworth, the managing director of Heating World at the relevant date and Mr Smart and Mr Lansdale who assembled the boilers in question. The central question was whether they were two versions of the Beta Boiler or not. On this issue, Mr Bosworth, Mr Lansdale and Mr Smart gave evidence and were cross-examined.


  3. The invention of the patent is said to relate to domestic and industrial water heating boilers of the balanced flue type. A balanced flue boiler is mounted against an external wall, the flue and air inlet protruding through the wall of the building and for a short distance outside. Certain such boilers are so arranged as to be accessible in part from the outside of the building. The boilers with which the specification is concerned are defined as "a balanced flue boiler intended to be mounted on an external wall or to stand on the floor against an external wall to enable servicing, maintenance or most repairs without a requirement for access to the interior of the building". The specification defines such a boiler as a "boiler of the kind described" and the invention is described by reference to such boilers. The specification describes the internal construction of a boiler of the kind described in terms which were not criticised:

    Water heating boilers of the kind described are commonly formed as a double skinned box which can be open or closed at the top or bottom. The inner skin defines the combustion chamber and the water to be heated flows between the inner or outer skins. The combustion gases are usually directed around the combustion chamber by a plurality of baffles and, and a result, the baffles usually have to be removably mounted to enable adequate access to the interior of the boiler for servicing and the like.

  4. It is necessary to say a few words about baffling within boilers. The purpose of the baffles within the boiler to constrain the flow of the hot gases from the burner so as most efficiently to bring them into contact with the walls of the boiler. It is no good if the hot gas from the burner passes straight into the flue without being encouraged to flow over as much of the surface of the inside of the combustion chamber as possible. Accordingly, boilers were at the priority date conventionally provided with one or more baffles to encourage the combustion gases to follow a tortuous path. The baffles might themselves contain water passages, and such an arrangement in respect of the principal baffle is the subject of claim 2 of the patent in suit, which is not alleged to possess independent validity.

  5. The patent in suit is thus addressed to a designer of boilers. I heard evidence both from Mr Sapey (who gave his own expert evidence) and from Mr Sutherland, who gave evidence on behalf of Trianco, of the nature of such a person. Mr Bosworth's evidence concerning the design of the Beta boiler also gave some insight into the way in which boilers were designed at the priority date. A sustained attack was made on Mr Sutherland's independence, based on his close association with the Oil Firing Technical Association of the Petroleum Industry, of which Trianco is a member. This attack failed. Mr Sutherland was not partial in his evidence. I should add that Mr Sapey was objective in giving his evidence and did his best to assist me.

  6. It seems that a boiler designer will have experience of design of castings of this sort. With the advent of boiler standards, the trial and error type of design process which was, I think, still current at the priority date has certainly diminished or vanished altogether. At the priority date, the designer would experiment with different baffle arrangements so as to reduce the temperature of the outlet gases in the flue, and thus increase the efficiency of the boiler. It was established that the addressee of this specification would work in this general way, and that he would be particularly conscious of the need to avoid 'short-circuiting' the gas flow by providing a direct flow from the burner to the flue, and that there must be at least one baffle (referred to at trial as the primary baffle). It was established practice, and had been for many years, to provide access to the combustion chamber through the aperture provided by the removal of the burner, and it had been the practice of service engineers to use the aperture left by removal of the flue for certain cleaning operations, if possible. It was however the practice to provide access to the secondary chamber by means of a removable access panel.

  7. The invention consists of an expedient for reducing the requirement for removable baffles and for facilitating service, maintenance and repairs. The claim is as follows:


    A boiler of the kind described comprising



    a double skinned casing


    of which the inner skin defines a combustion chamber


    and water to be heated flows between the skins,


    a fixed baffle which divides the combustion chamber into a primary chamber and a communicating secondary chamber,


    a burner which extends through an opening in the casing into the primary chamber for the introduction of burning fuel therein to, and


    a flue pipe which extends through an opening into the casing into the secondary chamber for the exit of spent combustion gases,


    whereby, by removal of said burner and said flue pipe, both the primary and secondary chambers accessible through said openings for servicing, maintenance and repair purposes

  8. The idea of the patent in suit is that both chambers of the boiler should be accessible, the secondary chamber merely by removal of the flue pipe and the primary chamber by removal of the burner. The internal parts of a boiler need to be accessible for the purposes of maintenance, and particularly for cleaning. If separate access panels formed in the wall of the boiler can be avoided, there is an advantage in that the water jacket has a greater area exposed to the hot gases within the boiler, and that servicing may conveniently be carried out from the exterior of the building.

  9. Claim 3 is also of importance in the present case. This claim is to a boiler according to Claim 1 or Claim 2, wherein the flue pipe extends sufficiently far across the secondary chamber as to constitute a secondary baffle.

  10. The principal question of construction which arises on Claim 1 is the meaning of the words "flue pipe which extends through the casing". The reason that this question arises is best appreciated by considering the alleged infringement, which it is convenient to do at this point.


  11. In the Eurostar boiler, the secondary chamber is located above the primary chamber and is separated therefrom by a water-cooled baffle. It also contains a removable secondary baffle which is not fixed, resting on four pegs above the generally horizontal primary water-filled baffle. The greater part of the secondary chamber above the primary baffle and the second baffle is occupied by what is called an "acoustic cassette". This acoustic cassette is fixed to the outer wall of the boiler by four thumb screws running upon four studs which extend through a flange formed at one end of the acoustic baffle. The baffle itself consists of a box filled with fire-resistant fibrous material in which there is a channel which is formed to which combustion gases gain access through a slot formed in the upper surface of the cassette. The channel communicates with the flue pipe which is bolted to the flange to which I have already referred, and which is plainly intended to be removed with the cassette. In use, the cassette is inserted into the secondary chamber through its wall and fixed in position by the thumbscrews. Combustion gases flow up over its walls and into the channel formed in its upper surface, thus passing to the gas flue.

  12. What the Trianco says is that the only part of the arrangement which is identifiable as a flue pipe is connected by its bolts to the outside of the cassette and there is thus no "flue pipe extending through" an opening of the casing into the secondary chamber. It is accepted that the round pipe portion is not normally intended to be detached from the cassette for purposes of servicing and maintenance, and it accepts that the cassette when removed from the boiler carries with it the pipe.

  13. It seems to me to be perfectly plain that the word 'pipe' has a wide and general meaning. At the same time, I think that it is artificial to view the channel in the top surface of the cassette as being a pipe in the ordinary meaning of that word. There is a difference between a pipe and a channel, and this is a channel. Accordingly, I think it is better to view the construction of the defendants' cassette and pipe as a variant upon the features called for by the claim on a literal construction. The answer to the questions which Hoffmann J. suggests in Improver v. Remington [1990] FSR 181 as a means of applying the principles articulated by Lord Diplock in Catnic v Hill & Smith [1982] RPC 183 seems to me to be straightforward. First, it is quite plain that attaching the pipe to a flange itself attached to the surface of the boiler so as to provide an exit for the flue gases makes no difference to the way the invention of claim 1 works. Second, it seems to me that that would have been perfectly apparent to the skilled man at the date. There is certainly nothing in the specification which suggests that a pipe in the strict sense itself extending through the wall of the boiler is to be used to the exclusion of any variant. Accordingly, I conclude that Claim 1 of the Patent in Suit is infringed.

  14. The position in relation to Claim 3 is slightly more complicated. There is no doubt that it is one of the functions of the cassette to baffle the gases. However, the requirement of the claim is that the flue pipe should extend sufficiently far across the secondary chamber as to constitute a secondary baffle. Here, the flue pipe is attached to the front surface of the cassette which can be viewed itself as a detachable baffle. The gas flow is not through the end of a cassette but into the channel formed in it largely from above. The variant is thus the use of a wide baffle with which the flue pipe is associated. This is not giving the flue pipe the additional function of baffling. It seems to me that the purpose of Claim 3 is to define an invention in which the flue pipe itself does have such a dual function. There is no indication in the specification that (for example) it would be possible to use a wide baffle of a conventional sort with a flue pipe attached to it in such a way that the whole was removable in one piece. It must of course be recognised that the U-shaped section of the cassette has the function of leading the exhaust gases to the pipe proper. However, in no sense can it be described as a pipe or pipe-like arrangement. It is a channel and it is intended that gas should flow into it at all points along its length. The basic idea of the baffle provided by the flue pipe of the Patent in Suit is that the gases should be baffled so that they flow into the end of the pipe distant from the wall in which it is mounted. This is not what happens in the alleged infringement. On the whole, I have come to the conclusion that the first of the Improver questions must be answered adversely to the patentee. It follows therefore that Claim 1 of the patent in suit is infringed but Claim 3 is not.

  15. Claim 10 is a method claim. If dependent on claim 1, it is infringed by virtue of subsection 60(2) of the Patents Act 1977 by supplier of the allegedly infringing boiler. As dependent on claim 3, it is not infringed.


  16. I first consider the evidence as to the Beta boiler. The evidence of Mr Lansdale established that the Beta boiler was made by sub-contractors called Reptal who welded an internal pipe through the double wall of the boiler. The flue was attached by a single bolt on the outside of the boiler. Neither Mr Lansdale nor Mr Smart who gave evidence on the part of the claimant had ever measured the protrusion of the pipe into the boiler. For the reasons I have given in considering construction of the claim above, the dispute as to the extent of protrusion is relevant only to question of claim 3. But it is clear from an examination of a Beta boiler in position that the effect of removal of the flue pipe is not to render "the secondary chamber accessible" through the opening provided. An installed example of the boiler was located by the defendants and plainly shows a separate access panel through which access is gained to the secondary chambers. While it is no doubt possible to gain some degree of access through the pipe exposed when the flue is removed, this is plainly not the kind of access with which the specification is concerned. The specification seems to me to exclude the possibility of substantial access being obtained otherwise than through the aperture left when the flue pipe is removed. Accordingly, the allegation of anticipation of claim 1 fails.

  17. I think that the evidence did establish that some examples of the Beta boiler with pipes extending 65mm or so into the combustion chamber were made and sold. Such an arrangement could not provide access to the combustion chamber unless the part of the flue protruding into the combustion chamber were also removed: but it was welded into position.


  18. Before turning to the substantial attack, I should consider the less close items of prior art. The Perkins boilers seem to me to have nothing to do with the case. Access to the boiler was by removing its top. One at least is a balanced combustion unit intended to be installed so as to be accessible from outside the building, but the evidence was that the burner was only accessible from the inside of the building. The Perkins boilers are irrelevant to the issues.

  19. The Walljet boiler is a boiler in which neither the burner nor the flue are accessible from the exterior of the building. The CentraJet is open to the same comment. There is no doubt that the Beta boiler presents the best starting point for an allegation of obviousness.

  20. Obviousness in this case can be approached by way of the four-step analysis described by Oliver LJ in the Windsurfing case [1985] RPC 59. In this case, the inventive concept lies in the combination called for by claim 1: it is the combination of a removable pipe and removable burner to provide access to the different parts of the boiler. There is a short point: is it obvious to alter the Beta boiler by extending the inspection panel clearly visible in the photographs and attaching the flue pipe to the removable panel? This step seems to me to be pre-eminently the kind of alteration to an existing design which a patent should not prevent. It is what is sometimes called a workshop variation. It is the sort of thing that any designer, however uninventive, would consider as a possibility to be accepted or rejected depending upon the other constraints place upon him. Claim 1 is obvious.

  21. Claim 3 requires the length of pipe extending into the combustion chamber sufficiently to provide a baffle. With this claim, a pipe in the strict sense has to extend through the wall of the boiler, and has to provide a baffle. This claim will only be bad if it was also obvious to alter the Beta boiler so as to render the whole of the flue pipe removable, and lengthen it. I was not impressed by the evidence that the 65mm extension had any substantial baffling effect at all. Mr Sutherland's evidence was that 'it was a fairly logical step to extend the flue pipe back into the heating chamber to form a baffle.' He relies upon the fact that the Beta boiler (65mm version) had this feature, but I am far from satisfied that it did. This case is very near the line indeed, but there is insufficient evidence for me finally to be satisfied that to use a removable flue pipe extending sufficiently far across the boiler was obvious. Claim 3 is valid.

  22. Claim 10 falls with claim 1, but is also obvious in the light of common general knowledge, unless limited to a flue pipe of the kind contemplated by claim 3.


  23. In the result, claim 1 of the patent in suit is infringed, but is invalid. Claim 3 is valid, but not infringed. Claim 10 is valid only if tied to claim 3, but must be revoked unless tied to this claim, when it will not be infringed.


Improver v. Remington [1990] FSR 181

Catnic v Hill & Smith [1982] RPC 183

Windsurfing [1985] RPC 59


Douglas Campbell instructed by Leathes Prior for the Claimant

John Lambert instructed by Keeble Hawson for the Defendant

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