FORM-2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL
Specification
(See section 10 and rule 13)
HEATING SYSTEM TYPICALLY BOILERS, HOT WATER GENERATORS, THERMIC FLUID HEATERS
AND THE LIKE
THERMAX LIMITED
an Indian Company
Chinchwad, Pune 411 019, Maharashtra, India
THE FOLLOWING SPECIFICATION DESCRIBES THE INVENTION.
1

FIELD OF INVENTION:
This invention relates to boiler / hot water generator / thermic fluid heaters and the like.
PRIOR ART:
It is already known in the prior art of generating steam / hot water / hot thermic fluid by exchanging heat in a heat exchanger located in the flue gas path where the hot gas exchanges the heat by convection.
DRAWBACKS OF THE PRIOR ART:
The drawbacks are:
1. Low heat transfer coefficient
2. Tubes in the gas path are prone to chemical attack by corrosive hot gases
3. Slagging and fouling the surfaces in furnace as well as in the heat exchanger
In particular this invention relates to equipment for gas to solid heat transfer and development of heat exchanger to transfer heat from solids to tubes containing water / thermic fluid having a higher heat transfer coefficient than heat transfer coefficient encountered in conventional gas to tube heat exchanger.
OBJECTS OF THE INVENTION:
An object of this invention is to propose a new concept of heating system without a convection bank in the gas path.

Another object of the invention is to propose a new type of heat exchanger for the heat transfer from hot gas to solids.
Another object of the invention is to provide a new type of heat exchanger for the heat transfer from hot solids to tubes
containing water /
steam / thermic fluid.
SUMMARY OF THE INVENTION:
There is provided a boiler / hot water generator / thermic fluid heater, having better heat transfer coefficients in heat exchange between solids and tubes compared to conventional heat transfer between gas and tube and without having any risk of fouling / corrosion due to no direct contact of flue gas with heat transfer surface.
It is envisaged that the heat exchanger requires no cleaning of heat
transfer surfaces and there is also reduction in heat transfer area than required for heat transfer by convection in the prior art.
In accordance to this invention there is envisaged a firing system capable of burning single or multi-fuel. There is also a fluidized bed solid fuel fired unit with or without inbed heat extraction depending on the fuel.
BRIEF DESCRIPTION OF THE DRAWINGS:
The invention will be described in detail with reference to a preferred
embodiment. Reference to this embodiment does not limit the scope of
the invention.
In the accompanying drawings:
FIG. 1 and 2 illustrate the schematics of the proposed system. (1) is the
normal known conventional combustor either Fluidized bed or Traveling

grate or any other firing system like static grate / pulsating grate, etc. with or without "inbed heat exchanger" (IBH) (2), extracting heat from the
bed, capable of combusting any conventional / agro-based solid fuels. Solid fuel is fed into the combustor by any known means and the air is supplied with the assistance of blower/blowers (forced draft) FD fan (3). The products of combustion (flue gas) then exchanges heat with solids flowing downward in a void (4), which forms a part of the furnace. The heated solid particles are then collected over the heat exchanger (5) superheater followed by another heat exchanger (6) evaporator, by
gravity. The hot particles thus exchanges the heat in respective heat exchangers (5) and (6) and gets cooled down to a sufficient level. The cooled particles are discharged through a known device (7) like rotary feeder / screw conveyor into a sieving mechanism (8) where the course ash is taken out. The sieved sand is then lifted to the top of the furnace using a known device (9) like bucket elevator / dense phase conveyor,
etc. The sand is then fed into the furnace through a dispensing device
(10). The cooled flue gases are then discharged to the down stream
system either to air preheater (11)/ dust collector (12) and finally to ID fan (13) into the atmosphere.
ADVANTAGES OF THE NEW INVENTION:
The following are the advantages of the invention:
1. Better heat transfer coefficients in the heat exchangers
2. Eliminate the risk of fouling / corrosion due to no direct contact of flue gas with heat transfer surface
3. Provides a new concept of self-cleaning mechanism for heat transfer surfaces
4. Reduction in heat transfer area than required for heat transfer by convection.

5. Multiple fuel capability irrespective of fuel characteristics
While considerable emphasis has been placed herein on the specific structure of the preferred embodiment, it will be appreciated that many alterations can be made and that many modifications can be made in the preferred embodiment without departing from the principles of the invention. These and other changes in the preferred embodiment as well as other embodiments of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

Dated this 7th day of April 2006

Mohan Dewan
of R. K. Dewan & Co
Applicant's Patent Attorney