FORM-2
THE PATENTS ACT,1970
(39 of 1970)
COMPLETE
SPECIFICATION SECTION 10
TITLE
" A SOLAR CONCENTRATOR "
APPLICANT
ECOSOLAR SYSTEMS (INDIA) LTD., an Indian Company, of 117/A/2 Pune-Sinhgad Road, Parvati, Pune 411 030, Maharashtra, India
The following specification particularly describes the nature of the invention and the manner in which it is to be performed:

The present invention relates to a solar concentrator. The invention particularly relates to a light weight paraboloid solar concentrator of a specific design.
Fuels are required in our daily life for varius purposes including cooking and heating. In most of the developing and underdeveloped countries, domestic fuel includes primarily wood, kerosene, coal, gas etc. All these fuels come from the natural resources. Since the supply of the resources is limited and is fast depleting with the increased use by the exploding population, the requirement of alternative source of fuel, becomes imperative. However, these fuels produce gases and ashes which pollute the environment. Further, cutting of woods and forests has been a matter of concern for environmentalists fromthe world over.
Solar energy is on the other hand free and is available in abundance. If we can detect a smart and efficient way to utilize this energy for cooking and heating, it would save a lot of natural resources, namely both the fuel and money at the same time.
Box type solar cookers and concentrators are widely known and are used for the purpose of cooking and heating. These technologies were known since several years. The box type cookers generally give temperature only upto 90-95°C. The concentrators, on the other hand can reach higher temperature depending upon the effective aperture area.

It is known to have paraboloid concentators. These concentrators were made of reflectors which may be of metal, glass, polymer or composite materials. A separate structure was provided to form and retain the paraboloid shape. The focal point of the paraboloid may lie within or away from the paraboloid. In order to maintain position of the paraboloid while tracking the sun, different methods such a friction locking, inserting pins, tying with rope or chain, etc. were employed. The structure itself had to be moved in many cases while sun tracking in such a scenario. The designers had provided castors or wheels to the structure in the past to meet the problem.
The known solar concentrator suffers from various drawbacks namely the design of such solar concentrator does not ensure self balance of the paraboloid at any particlar position. Hence, use of counter weight becomes necessary. However, the centre of gravity and the focal-point of the known concentrators do not coincide, therefore the mode of rotation does not pass through the same point.
In known solar concentrators and the clumsy structure therefore make them costly and thus occupy more space for their installation. Furthermore, installation and packing becomes cumbersome and time consuming for the known solar concentrator.

To avoid the disadvantages of the known solar concentrators, it has been the endeavour of the applicant to fabricate an improved solar concentrator of specific design which can be easily installed and/or dismantled. It was also the endeavour of the applicant to produce a cost effective and more efficient solar concentrator.
Thus the object of the present invention is to fabricate
and design a solar concentrator which ensures full balance of
the paraboloid structure at any positioin and thereby dispensing
with the use of counter-weight.
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A further object of the present invention is to fabricate
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a solar concentrator so that the centre of gravity and the focus point of the paraboloid with structure coincide.
Another object of the present invention is to have a solar concentrator having the centre of gravity, and the focus point and also the mode of rotation pass through the same point thereby ensuring minimum distortion of the focus.
A still further object of the present invention is to have a modular design corresponding to the solar concentrator which ensures ease of manufacturing it and hence cost effective.

Yet another object of the present invention is to have a paraboloid construction of a solar concentrator having modular concentration which ensures easy assembly and packing for transportation.
A further object of the present invention is to have a solar concentrator which requires low maintenance compared to the known solar concentrators.
Thus according to the present invention there is provided a specifically designed paraboloid concentrator of the type described hereinafter.
Thus the present invention provides an improved solar concentrator comprising a paraboloid shaped structure having excellent inner reflectivity, said paraboloid structure being so fitted to a A- shaped frame that the centre of gravity of said paraboloid structure and the axis of rotation of said frame being identical, a pivot being provided to allow a rotation of 360° of the paraboloid structure, said paraboloid structure being further attached to a hinge with the help of a support ring, said solar concentrator being further provided with a tracking pin to ensure proper alignment of the axis of said paraboloid structure so as to have said axis being parallel to sunrays.

In the aforeaaid improved solar concentrator of said paraboloid structure is made of sheet metal or polymer or like material having excellent reflectivity,' said paraboloid structure is made by arranging petals by sticking, stapling or fixing with the help of nut-bolts, tags etc. in a known manner.
In the improved. solar concentrator of the present invention, said paraboloid is maintained in a predetermined location with respect to the hinge to have a perfect balance. The frame of the paraboloid structure is rested on a three-legged stand for a stable support to ensure proper alignment of the axis of the paraboloid structure.
The applicant had developed a specially designed parabolic concentrator. This is an efficiently designed solar concentrator where high temperature can be achieved. The high temperature contributes to speedy heating and cooking. There is no need to wait for hours after keeping the utensil in the sun. Such concentration can be used with a pressure cooker blackened from outside, or any other blackened utensil.

The solar concentrator of the present invention are easy to instal, operate and to maintain. They are available in the form of a completely knocked down kits, which can be assembled in short time. This model is suitable for urban, rural, tribal areas for the use in household, community kitchens, hotels, hostels, remote campuses and for various other applications. The construction and the working of the solar concentrator of the present invention will be described in detail with reference to the accompanying drawings.
Figure 1 represents a paraboloid.structure of the known solar concentrator.
Figure 2 illustrates the paraboloid structure of the
improved solar concentrator of'the present invention, and
Figure 3 illustrates the construction of the solar concentator of the present invention.
With reference to Figure 1 of the accompanying drawings, all the rays coming from the sun are concentrated at the point of focus (F) as long as the axis of the paraboloid is parallel to the rays of the sun. The centre of gravity (C.G) of the paraboloid usually lies within the curved area. The axis of rotation (R) should be ideally passing through the point of focus (F). A counter weight (C.W.) has to be provided to reduce the efforts required for tracking.

As illustrated in Figure 2, the improtant point regarding the concentrator is that the focal point and centre of gravity are on the focal axis and the two points are made to coincide.
The focal point for paraboloid is a geometrical character. It depends upon the rim angle, height and aperture of the paraboloid. These points are explained in Figure 2 of the drawings, wherein
r = Rim angle
f = Focal point where the. sun rays are focussed
h = Height of the .paraboloid
A = Aperature area through which solar rays enter
The focal axis is the line joining the focal point and
the sun.
The centre of gravity of the system can be changed as per requirement, eg. if one puts some weight at the rim, then the centre of gravity can be lifted, if weights are added at the lower part of the paraboloid, then the centre of gravity can be lowered.
The basic principle of this invention lies in the concept that the centre of gravity is changed and brought at the focal point as per the design by suitably adding weights at required point.
<■However, the rim angle must be eater than 90.
With respect to figure 3, the construction of the solar concentrator of the present invention consists of a paraboloid (1). It is the surface generated by rotating a parabola around its axis. Such surface has the characteristic that all the rays parallel to its axis falling on it are reflected to one common point, which is the focal point of the paraboloid. The paraboloid (1) of the present invention is made up of sheets of metal or polymer or the like, having excellent reflecting surface on the inside. The shape itself is made of several petals (2), facilitating modular construction. The number of petals could be any say eight to even fifty or more, "depending on the size of the paraboloid and the design. Before assembly the petals could be flat or may have the curvature of the paraboloid. The shape of the paraboloid is created by sticking or stapling or fixing the petals together by any other means like nut-bolts, tags etc. An "A" shaped frame (3) that may have or any other suitable shape as well is used to hang the paraboloid about hinges (4). The centre of gravity of the paraboloid lies within its own volume. In the said invention, the paraboloid and the other construction is made in a way such that the axis on which it is hung and about which it is rotated passes through the centre

of gravity. The design is also made such that the focal point of the paraboloid and the centre of gravity coincide. The design allows the paraboloid to rotate about the axis of rotation, line between the hinges (4), and also allows it to stay in any angular position in perfect balance. A multi-legged (minimum 3) stand (5) is provided for stable support on the ground. A pivot (6) is provided to allow 360° horizontal rotation (about the vertical axis) of the paraboloid. The rotations around the axis passing through the hinge points and around the vertical axis are used to track the sun, such that the axis of the paraboloid is parallel to the sunrays. The wing nuts (7) are given on both the rotation axes so that the position' of the paraboloid could be fixed or locked. The paraboloid is attached to the said hinges (4) with the help of the support ring (8). The tracking pin (9) is provided to ensure proper alingment of the axis of the paraboloid with the sunrays. Saddle (10) is provided near the focal point of the paraboloid so that the material to be heated or cooking vessel or a heat exchanger or target (11) could be placed and supported. The heat from the sun is thus concentrated on the target. The target may be painted black to allow for maximum absorption of solar radiation.
The following advantages are ensured in the improved solar concentrator of the present invention.

It will be clear from the above description that the improved design of the concentrator ensures subsances of the paraboloid in any position; hence the use of counter weight is not required.
The centre of gravity, the focal point coincides and the axis of rotation passes through the same point, thereby ensuring minimum distortion of the focus.
The modular construction ensures ease of manufacturing, hence cost reductino is possible.
The modular construction ensures ease of packing and
transportation.
The concentrator is made into a "Do it yourself" kit, due to the ease of assembly.
It will be appreciated that' obvous alteration and modification of the paraboloid solar concentrator of the present invention will be possible and is within the knowledge of a person in the art.
The present invention therefore includes within its scope not only what is described and illustrated herein, but also those modications and alterations which are within the knowledge of the art of construction of solar concentrators.

WE CLAIM:
1. An improved solar concentrator comprising a paraboloid
shaped structure (1) having excellent inner reflectivity, said
paraboloid structure being so fitted to a A-shaped frame that
the centre of gravity of said paraboloid structure and the axis
of rotation of said frame being identical, a pivot being provided
to allow a rotation of 360° of the paraboloid structure, said
paraboloid structure being further attached to a hinge (4) with
the help of a support ring (8), said solar concentrator being
further provided with a tracking pin (9) to ensure proper
alignment of the axis of said paraboloid structure so as to have
said axis being parallel to sunrays.
2. An improved solar concentrator as claimed in Claim 1 wherein said paraboloid structure is made of sheet metal or polymer or like material having excellent reflectivity.
3. An improved solar concentrator as claimed in Claim 1 or 2 wherein said paraboloid structure is made by suitably arranging petals by sticking, stapling or fixing in a known manner.
4. An improved solar concentrator as claimed in any one of the preceding claims wherein said paraboloid structure is maintained in a predetermined location with respect to the hinge (4) to have a perfect balance.

5. An improved solar concentrator as claimed in Claim 4 wherein said frame is rested on a three legged-stand (5) for a stable support.
6. An improved solar concentrator as claimed in any one of the preceding claims wherein said paraboloid structure is attached to said hinge (4) with the help of a support ring (8) and a tracking pin (9) to ensure proper alingment of the axis of the paraboloid structure.
7. An improved solar concentrator as claimed in any one of the preceding claims which further comprises a saddle (10) located at the focal point of the paraboloid for placing the cooking
'vessel (11).

8. An improved solar concentrator as substantially herein
described and as illustrated in , the drawings accompanying the
Provisional Specification.
Dated this 6th day of May 2002.
M K CHAKRABARTI OF L S DAVAR & CO Agent for the applicant