Refusal of a patent application based on prior art not cited in hearing notice set aside by the Delhi High Court

In a recent decision, the Delhi High Court set aside an order of the Controller of Patents, because the refusal was based on a ground not cited in the hearing notice. The patent application in the case related to “Particle Separator and Method for separating particles out of an Exhaust Stream of an Internal Combustion Engine” bearing application no. 1241/DEL/2009. The application was filed by Man Truck Bus Se, a commercial vehicle company that focuses on eco-friendly technologies.

The final amended independent claim that was refused reads as follows:

We Claim: 

  1. A particle separator for separating particles out of an exhaust stream of an internal combustion engine, it being possible for an exhaust stream (2, 7) to flow through the particle separator (1), wherein flow regions (5, 6) which differ with regard to the flow conditions are formed in the particle separator (1), and wherein the flow regions (5, 6) are configured such that particles (3, 4) of different defined size or different, defined mass are adapted to be separated out of the exhaust stream (2, 7) in the different flow regions (5, 6), characterised in that different flow regions (5, 6), which are spatially separated from one another, are formed for separate separation of defined ultrafine particles (3) primarily by diffusion and in contrast defined larger or heavier coarse particles (4) owing to their mass moment of inertia, wherein the different flow regions (5, 6) are formed by different sizes of free flow cross-sections.”

The Controller refused the patent application based on 5 prior art references – D1 to D5. While references D1 to D4 were cited in the examination report as well as the hearing notice, D5 was brought up by the Controller only during the hearing. Despite the aforesaid, the applicant responded to D5 along with D1 to D4 in its written submissions following the hearing.

After reviewing the facts, the Court set aside the refusal order based primarily on the following reasons:

  1. The refusal was based on a prior art reference not cited in the First Examination Report or the hearing notice, thereby depriving the applicant a reasonable opportunity of responding to the same;
  2. The portion of the order regarding D1 to D4 merely reproduced the prior art references, but did not analyse the same to arrive at a conclusion of inventive step;
  3. The refusal order merely reproduced paras from the examination report, and did not consider the responses filed by the patent applicant; and
  4. The details regarding grants in the US, Europe, and so on after reviewing similar prior art references were not considered.

Setting aside the order, the Court asked the Controller to fix a hearing within 4 weeks and pass an order within 3 months thereafter following fresh consideration.

Citation: Man Truck Bus Se vs Assistant Controller of Patents Designs, High Court of Delhi, 09th February, 2024, C.A.(COMM.IPD-PAT) 16/2022


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