Title of Invention

"A FIBRE REINFORCED MOULDED FAN BLADE"

Abstract

This invention relates to a fibre reinforced moulded fan blade characterized in that said fan blade is hollow in construction with a high cambered aerofoil profile with 10-25 mm camber and 115-290 mm of chord width having a thickness of 1 5-4 5 mm decreasing from root to tip of the fan blade wherein the reinforced plastic comprising of polyester resin together with glass reinforcements in a ratio of 2:1 to 1:1. (Fig-1)

Full Text

FIELD OF INVENTION This invention relates to a fibre reinforced moulded fan blade. In particular, this invention relates to fan blades of fibre reinforced plastic. PRIOR ART Fan blades presently known in the art are made of metal and formed by the step of casting. Such fan blades are of thin profile. However, it has now been found that such fan blades that such fan blades are not efficient. OBJECTS OF THE INVENTION An object of this invention is to propose a fibre reinforced moulded fan blade made of fibre reinforced plastic. Another object of this invention is to propose a fibre reinforced moulded fan blade which is efficient. Yet another object of this invention is to propose a fibre reinforced moulded fan blade made of fibre reinforced plastic which is no longer formed by the step of casting but by the method of moulc ing. Further objects and advantages of this invention will be more apparent from the ensuing description. STATEMENT OF INVENTION According to this invention there is provided a fibre reinforced moulded fan blade characterized in that said fan blade is hollow in construction with a high cambered aerofoil profile with 10-25 mm camber and 115-290 mm of chord width having a thickness of 15-45 mm decreasing from root to tip of the fan blade wherein the- reinforced plastic comprising of polyester resin together with gb.bs reinforcements in a ratio of 2:1 to 1:1. DESCRIPTION FIGURE This invention will now be illustrated with accompanying figures which illustrate embodiment of present invention and are not intended to be taken restrictively to imply any limitation on the scope of the present invention. In the accompanying figures: Fig. 1: shows the construction of the fan blade of the present invention. Figs. 2A-2D : show exemplary embodiment of mould used in the present invention. DESCRIPTION OF INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS Referring to fig. 1, the fan blade of the present invention is moulded from fibre reinforced plastic comprising of polyester resin together with glass reinforcements in a ratio of 2:1 to 1:1 wherein the glass reinforcements comprises 25-35% by weight of chopped strand mat, 40-50% by weight of Rovings and 20-30% by weight of woven glass cloth. By way of example, the resin is isophthalic or epoxy res in . The blades are hollow in construction with a high cambered aerofoil profile with 10-25 mm of camber and 115-290 mm of chord width having a thickness of 15-45 mm. As the fan blades are hollow in construction, the wall thickness varies from root to tip and such a thickness decreases. Further, the glass reinforcements are distributed from the root to tip of the fan blade. The mould used for making the blade is made of fibre reinforced plastic material with adequate reinforcements, wood and iron. The mould is made in two halves as shown in fig. 2. The position and number of inlets of the mould for resin injection depends upon size and shape of the blade to be produced. The inner and outer dimension of mould is same. The process involved for moulding includes hand lay-up as well as vacuum infusion. The moulding is performed at room temperature and thereafter, the blade is left in the mould for 3 hours followed by curing in an electric oven at 65-75° wherein rollers and brushes are used to squeeze out air to prevent any void . After curing, compression is carried out by clamping the two halves. As the mould is in two halves, therefore the blade can be taken out by opening of clamps. The advantages of the invention as compared to the prior art are listed h.srrinbelow:- i. Elimination of core material ii. Lighter weight of the blades due to absence of core. iii. Elimination of core and lighter weight of the blade facilitates Competitive Product. iv. Ease of handling and maintenance due to lighter weight. v. Reduction in the overall thrust on mechanical drive system due to light weight of blades, which enhances life of bearings and drive system, vi. Less starting torque due to lighter weight of blades, which enables selection of lower rating of prime-mover. It has been found that such moulded fan blades provide improved results in comparison to the previously known cast blades. It is to be noted that the present invention is susceptible to modifications, changes and adaptations by those skilled in the art. Such, variant embodiments incorporating the concepts and features of the present invention are intended to be within the scope of the present invention, which is further set forth under the following claims:- CLAIM: 1. A fibre reinforced moulded fan blade characterized in that said fan blade is hollow in construction with a high cambered aerofoil profile with 10-25 mm camber and 115-290 mm of chord width having a thickness of 15-45 mm decreasing from root to tip of the fan blade wherein the reinforced plastic comprising of polyester resin together with glass reinforcements in a ratio of 2:1 to 1:1. 2. A fibre reinforced moulded ian blade as claimed in claim 1 wherein the glass reinforcements comprises 25-35% by weight of chopped strand mat, 40-50%) by weight of Rovings and 20-30% by weight of woven glass cloth and resin is for example isophthalic or epoxy resin. 3. A fibre reinforced moulded fan blade as claimed in claim 1 or 2, wherein glass reinforcements are distributed from the root to the tip of fan blade. 4. A fibre reinforced rnoukird fan blade substantially as herein described and illustrated.

Documents:

670-del-2002-abstract.pdf

670-del-2002-claims.pdf

670-del-2002-correspondence-others.pdf

670-del-2002-correspondence-po.pdf

670-del-2002-description (complete).pdf

670-del-2002-drawings.pdf

670-del-2002-form-1.pdf

670-del-2002-form-18.pdf

670-del-2002-form-2.pdf

670-DEL-2002-Form-3.pdf

670-del-2002-form-4.pdf

670-del-2002-form-5.pdf

670-del-2002-gpa.pdf

670-del-2002-petition-137.pdf

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