Revocation Application/ Proceeding Summary: Improved Diffuser for an Air Conditioning System

Applicant in this case is M/s Air Master Equipments India (P) Ltd and Respondents are:

  1. Mr. Ramesh Nana Mhatre, who is the inventor and Applicant of the granted patent application being discussed, and
  2. Controller of Patents who granted the patent post examination and prosecution. Title of the application is ‘An improved Centre Core, Intermediate Core and an outer frame for a diffuser for use in central air conditioning system and an improved diffuser incorporating them and the method of manufacturing the same’ and case number is TRA/1/2008/PT/CH. The order number of case being discussed is NO 75/2011

 To brief a bit on the understanding the subject matter, in a central air conditioning system, air that is conditioned to a desired temperature at one source is distributed to various places through a network of ducts, and a diffuser is required at every outlet of the duct. Generally, these ducts are of square or rectangular cross section, most probably due to their easy self-resting and properly adjusting nature in corners of the ceiling in the buildings and vehicles, and therefore the diffuser used at the outlet of an air distribution duct is also of square or rectangular shape. The diffuser fitted at the end of the air distribution duct projects/exposes out from the ceiling of a room or any other space required to be air conditioned, and therefore plays a part in interior decoration or overall look of the room/space. Respondent, through his invention, therefore wishes to solve following drawbacks in existing diffusers:

  1. Sometimes, the side sections of each core and outer frame are welded together at corners to avoid gaps, or corner sections, after fixing into the grooved channel sections on the back of two adjacent side sections, are crimped for assembly. The cores are inter-connected through connecting strips that are welded to the collars of each core. The welding and crimping operations require extra equipment as well as these operations are very time consuming thereby increasing the cost of production.
  2. Due to the grooved channel sections at the back side of each side section and corner sections used for the assembly or cores, the weight of the diffuser is increased which also increases the cost of production.
  3. To avoid gaps at the corners of the core(s), the side sections of the cores are produced with high precision, which increases the cost.
  4. On assembly some times there remains a gap between two side sections, at the corners of the core(s), due to which diffusers are rejected, resulting into a big loss of production i.e. material and labour and which further increases the cost of production.
  5. When a diffuser is attached to a duct and conditioned air is blown through the duct, it is noticed that the air is not diffused equally to all sides at the corner sections as the grooved channel sections or ridges at the back surfaces of the cores come in the path of air and disturb the equal and proper diffusion of air in all directions. The enclosed collars of the centre core and intermediate core(s) rebounds the air, thereby reducing the flow or air through corners of the diffuser.
  6. As the diffuser is manufactured in several pieces, which are assembled, manufacturing process is cumbersome, time consuming and labour oriented and increases the cost of production.
  7. Due to the grooved channel sections and corner sections or ridges and welding spots on the back surface of the core(s), dust is accumulated therein, which is difficult to clean.
  8. Dust is also accumulated in gaps at corners on the front surfaces of the cores, which gives a dirty look to the diffuser and tarnish interior decoration look of the room/space.

 A main object of this invention is therefore to obviate the above mentioned drawbacks of the existing diffusers and to provide an improved diffuser for central air conditioning system, wherein each of the central core and/or the intermediate core(s) and/or the outer frame are manufactured in a single piece and both the outer as well as inner surfaces of the cores and/or the outer frame are smooth without any extra section, projection or groove which dispenses with the requirement of extra material, and the time taken for assembly is also very much reduced and at the same time there is no obstacle in the flow path of air, which is diffused equally in all the directions. As the cores are manufactured in a single piece, there is no question of any gap at the corners thus no chance of rejection of the product and no need of any welding and crimping operations and hence the cost of production of the diffuser will obviously be very less.

 Respondent No. 2 (Controller of Patents) was satisfied that the invention was patentable and accordingly the patent was granted vide No. 181821 on 18th Jan, 1995. On 25th August 2006 the Respondent No. 1 sent a legal notice to the Applicant, wherein according to this notice, the Applicant was inter alia informed of the patent in favour of the Respondent and that the Applicant was not entitled to manufacture or sell air diffusers identical to the patented product or substantially similar to it. The Applicant sent a lawyer’s reply dated 13-9-2006 alleging that  the patented product was known in the market, it was neither new nor novel, and that there is concealment of material facts and that the patent was obtained by fraud. It was also alleged that the Respondent was nothing but a job-worker.

 After this exchange of correspondence, the Applicant filed O.P. 704 of 2006 before the Hon’ble Madras High Court for revocation of the patent. This was transferred to IPAB. Counter statement was filed and both sides also filed the evidence to support their case.  Applicant submitted that there was no novelty in the invention and it was obvious and also submitted that the main feature of the invention even according to the Respondent was that it was a single piece centre core to facilitate clean flow of air. He submitted that diffusers have been known for long and there was evidence to show that there was prior art where the single piece units were known. He referred to Series 5700 louvre face ceiling diffusers. From the paper book, he pointed out that there is specific reference to one piece stamped steel construction and that this prior art was also meant to provide an economic solution to air distribution problems requiring equal throw in all directions. According to him, this anticipated the patented product. Further, he submitted that if the only difference is the manner in which the inner assembly can be removed, that hardly qualifies for the grant of a patent.  He then referred to another prior art.  Series 5800 and 5800A louver face Directional Diffusers. He submitted that this too indicated provision of equal throw, quick release of inner assembly for immediate access and ease of installation. According to him, the fact that the prior art was used for ceiling air–conditioners while the patent product was for central air-conditioner will not make it non-obvious.  He also referred to Titus and Trox catalogues, without bearing any dates. On being asked to provide the dates of these documents, he was unable to give any acceptable evidence. Therefore, only two prior arts were provided by the applicant.

 Respondent (Patentee) on the other hand submitted that till 1995 there was no prior art that anticipated the claimed subject matter. All the single piece units were extruded aluminium, which meant that metal sheets were cut and joined. The patented product was, on the other hand, made as a single unit from a special die in a metal press.

 Respondent also produced, before the IPAB board, samples of the prior art and the patented product and submitted that it was wrong to call the Respondent a job worker and that he had won many awards and recognition of his expertise. He submitted that the patented product was supplied by the Respondent to persons in the same business not only in India but abroad too. He submitted that while the prior art shows joints, corners and gaps, the patented product is one smooth surface with no gaps or joints. Also, in the prior art, the assembly is detached by turning clockwise, whereas in the patent product, it is held by spring and is removed by applying pressure. He also submitted that in the prior art, there is a buttoned hole in the centre cone, while the patented product has an outwardly and downwardly directed slanting surface with neither a button nor hole. He submitted that the prior art has uneven surface and crimping and that the air is distributed by rebound, whereas in the patented product, there are no hindrances to the flow of air. The patented product has clear slots while the prior art does not. He further submitted that the prior art is limited to 2 or 3 cone inner assembly, whereas the patented product can have multiple cores depending on the requirement. The Respondent further pointed out to the tabular column in the Respondent’s counter statement where each and every distinguishing feature of the patented product is explained and submitted that the prior art does not teach the invention and that the patented produce is new and non-obvious.  He also submitted that, in addition to the counter statement, the Respondent has marked in evidence the affidavit of one Mr. Pankaj Dharker of impeccable credentials who has affirmed that the product is an invention. He submitted that there is no proof of wrongful use or suppression of information and therefore the Applicant can not raise these grounds without proof. As regards prior publication, the Respondent submitted that there should be material to show that it was published. Respondent further submitted that as regards the ETL report, no reliance can be placed on it without an affidavit to file it as evidence, and in any event, it only refers to diffusers constructed of extruded aluminium, which can not be prior art as far as this product is concerned.

 Submissions were heard and the matter was examined by Hon’ble Justice Prabha Sridevan, wherein it was concluded that the Respondent was most certainly not a job worker and that the evidence filed by the Respondent shows the number of awards and recognition of his merit that he has received from various people including the Government. It was further held that the Applicant also did not seriously urge that stand and that the applicant had not filed any evidence apart from the two prior arts to support its case. It was further stated that the Respondent, on the other hand, had filed a very important piece of evidence that was the affidavit of the expert in the field and spoke of the disadvantages that existed in the diffusers prior to 1995. Evidence of Pankaj Dharker showed that in the existing art, because of the corner sections and the grooved channels, flow of the air was obstructed and that there was a reduction of airflow because in the prior art air rebounded. It was also appreciated that the assembly of various parts was a costly process and that the prior art required joining of the various parts and if this was not done with a high degree of accuracy, there was likely to be higher rate of rejection. Furthermore, it was noted that the prior art designs were aesthetically inferior and that the accumulation of dust was high. His affidavit showed the prior art and the patented product in comparison, both with photographs and with explanatory notes. From the affidavit of the respondent and the supporting evidence, it was concluded that the prior art series 5700 and 5800 did not teach the patented product, and that the claimed subject matter was a new invention that served the object of the invention and also avoided the existing drawbacks of the prior art. 5700 and 5800 are the same except for the fact that 5700 has a 2 cone assembly, while 5800 has a 3 cone assembly. The TROX and the Titus catalogues were not considered since there was no date and It was not know if they are prior to the patented product, but the expert dealt with even those products and has given the opinion that they do not teach this invention. A test for obviousness was applied and it was concluded that the invention was non-obvious. In view of the reasons stated above, it was confirmed that the invention was novel and non-obvious and the revocation application was dismissed.

About the Author: Mr Ankur Sehgal, Patent Associate at Khurana and Khurana, Advocates and IP Attorneys and can be reached at: ankur@khuranaandkhurana.com

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