Claims:WE CLAIM:
1. An apparatus for manufacturing dual sand includes a crushing machine (1); a vibrating screen (2); and sand washer (5); graded aggregates from the vibrating screen (2) mixed with water is conveyed to the sand washer (5) and the washed sand from the sand washer (5) is fed to a de-watering screen (5a) and then fed to sand conveyor; characterized in that a balancing chute (7) is positioned between the de-watering screen (5a) and sand conveyors (8, 9) that includes an inlet (7a), a first outlet (7b), a second outlet (7c), and a regulating arm (7d),
wherein the sand from the de-watering screen (5a) is delivered to the balancing chute (7),
wherein the regulating arm (7d) is disposed for controlling the quantity of the sand delivered through the first outlet (7b) and the second outlet (7c),
wherein the regulated quantity of the sand from the first outlet (7b) of the balancing chute (7) is diverted to the first sand conveyor (8), which is used as first type of sand, and
wherein the regulated quantity of the sand from the second outlet (7c) of the balancing chute (7) is diverted to the second sand conveyor (9) which also receives pre-determined quantity of first graded aggregates from the vibrating screen (2) through a conveyor (4) and the mixture is used as the second type of sand.

2. The apparatus as claimed in claim 1, wherein the regulating arm (7d) is manually actuated.

3. The apparatus as claimed in claim 1, wherein the regulating arm (7d) is electro mechanically operated using pneumatic cylinder and actuated through compressed air and solenoid valves.

4. The apparatus as claimed in claim 1, wherein the regulating arm (7d) is actuated by a screw rod, and the rotation of the screw rod is controlled by an electric motor.
, Description:FIELD OF INVENTION
The present invention relates to a sand making apparatus. More particularly, the present invention relates to an apparatus for manufacturing sand, which produces sands for two different applications simultaneously with single input.

DESCRIPTION OF PRIOR ART
Sand is an important ingredient in the construction industry and by and large river sands are used for this purpose. Sand plays a very important role in the quality of the construction. For construction the sand must be properly graded depending upon its end use in the construction, particularly for use in the preparation of concrete and plastering mortars. River sand in many parts of the country is not graded properly and has excessive silt and organic impurities and these can be detrimental to durability of steel in concrete. Presence of other impurities such as coal, bones, shells, mica and silt etc makes it inferior for the use in cement concrete. The decay of these materials, due to weathering effect, shortens the life of the concrete. Removing sand from river bed impact the environment, as water table goes deeper and ultimately dry.

Because of its limited availability, the cost of natural river sand has become too high and its consistent supply cannot be guaranteed. Under this circumstances use of manufactured sand becomes inevitable. The equipments and method of manufacturing of manufactured sand is known in the art.

Standards are available for the grading of the sands for different applications in construction . For example Indian standard IS:1542 covers the requirements of naturally occurring sands, crushed sands and crushed gravel sands used in mortars for internal wall ceiling plastering and external plastering using mixes of lime, cement composite lime-cement, activated lime mixture (ALMP) of gypsum with or without admixture of sand.

Indian standard IS:383 covers the requirements of aggregates , crushed or uncrushed , derived from natural sources such as river terraces and river beds, glacial deposits, rocks, boulders and gravels, for use in the production of concrete for normal structural purposes including mass concrete works and manufactured sand.

Manufacturing of sand process generally involves three stages namely crushing, screening and washing or classification. The crushing of stones in to aggregates is done by equipment such as Jaw crushers, cone crushers and Vertical Shaft Impact crusher (VSI) where the stones are crushed into sand of required grain sizes (as fines). In the vertical shaft impact crusher (VSI) rock is fed onto a rotor which accelerates and then discharges the rock at high speed against rock beds in the crushing chamber. The impact of the rock against the rock beds induces fracture and breaks the rock and improves the surface structure of the particles.

The output material from the stone crusher is then fed to vibrating screen for separation. The vibrating screens are normally multi deck construction, for example 2 deck. The individuals screen decks are fitted with screens of pre determined size according to the requirement are arranged one above the other. While the coarser screen is arranged in the top deck, the fine screen is finding its place in the bottom deck. Generally the larger particles will be segregated by the upper screens and conveyed back to the crushing machine for re crushing. The screened material from the bottom deck of required grade is used for the indented application. The graded material is conveyed to the sand washer to eliminate unwanted fine particles present within such that the end product satisfy all the requirements of standards laid down to meet the required applications.

In a typical setup for sand making, the sieves of the vibrating screen is arranged so as to segregate aggregates of size 0 to 2.5mm, 5mm and 8mm.While the aggregates of size 75 microns to 2.5mm are used for plastering the aggregates of size 75microns to 4.75mm are used for concrete preparation.

The sands segregated by the vibrating screen are delivered to sand washer. In the sand washer the material is fully washed and the material with water is fed to dewatering screen of the sand washer. In the dewatering screen the water is removed and the sand with absorbed moisture is delivered to the conveyor and transported to the storing location within the plant.

In the known arrangements it is possible only to make any one particular type of sand for example sand of size 75microns to 2.5mm used for plastering application or the sand of size 2.5mm to 4.75mm for concrete preparation. Hence, if it is required to manufacture sand of two different particle sizes for example for plastering application and sand for concrete mixing, two separate sand manufacturing plants are required, which increases cost and manufacturing time required.
Accordingly there exists a need to have a sand making plant which will be capable of manufacturing sand for two different applications for example, sand for plastering application and sand for concrete mixing, which will be cost effective.

OBJECTS OF INVENTION
One or more of the problems of the conventional prior art may be overcome by various embodiments of the present invention.

It is the primary object of the present invention to provide a cost effective apparatus for manufacturing sand, which produces sands suitable for two different applications from a single input simultaneously.

It is another object of the present invention to provide an apparatus which is capable of manufacturing sand for plastering application as well as for concrete mixing simultaneously from a single input.

SUMMARY OF INVENTION
Thus according to the basic aspect of the present invention there is provided a sand making apparatus for manufacturing dual sand includes a crushing machine; a vibrating screen; and sand washer; graded aggregates from the vibrating screen mixed with water is conveyed to the sand washer and the washed sand from the sand washer is fed to de-watering screen and then fed to sand conveyor; characterized in that a balancing chute is positioned between the de-watering screen and sand conveyors that includes an inlet, a first outlet, a second outlet, and a regulating arm,
wherein the sand from the de-watering screen is delivered to the balancing chute,
wherein the regulating arm is disposed for controlling the quantity of the sand delivered through the first outlet and the second outlet,
wherein the regulated quantity of the sand from the first outlet of the balancing chute is diverted to the first sand conveyor, which is used as first type of sand, and
wherein the regulated quantity of the sand from the second outlet of the balancing chute is diverted to the second sand conveyor which also receives pre-determined quantity of first graded aggregates from the vibrating screen through a conveyor and the mixture is used as the second type of sand.

It is another aspect of the present invention, wherein the regulating arm is manually actuated.

It is another aspect of the present invention, wherein the regulating arm is electro mechanically operated using pneumatic cylinder and actuated through compressed air and solenoid valves.

It is another aspect of the present invention, wherein wherein the regulating arm is actuated by a screw rod, and the rotation of the screw rod is controlled by an electric motor.

BRIEF DESCRIPTION OF DRAWINGS:
Figure 1: of the drawings schematically illustrates an apparatus for manufacturing sand, which produces sands suitable for two different applications from a single input according to the present invention.
Figure 2: of the drawings schematically illustrate the perspective view of the balancing chute according to the present invention.
Figure 3: of the drawings schematically illustrate the perspective view of the balancing chute fitted to the dewatering screen according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS
The present invention as discussed hereinbefore relates to an apparatus for manufacturing sand, which produces sands for different applications simultaneously with single input.

Referring to Figures 1 ,2 and 3 the apparatus for manufacturing dual types of sand comprises a crushing machine (1); a vibrating screen (2); a sand washer (5); graded aggregates from the vibrating screen (2) mixed with water is conveyed to the sand washer (5), and the washed sand from the sand washer (5) is fed to a de-watering screen (5a) and then fed to sand conveyor, characterized in that said apparatus comprising a balancing chute (7) positioned between the de-watering screen (5a) and sand conveyors (8, 9), the balancing chute (7) as shown in Figure 2 includes an inlet (7a), a first outlet (7b), a second outlet (7c) and a regulating arm (7d).

The crushing machine (1) which may be for example a Vertical Shaft Impact crusher (VSI) or cone crusher. In the crushing machine (1) the stones are crushed into finer aggregates. The aggregates emerging from the crushing machine (1) are fed to a classifier for grading of the aggregates. It is to be noted that the invention describes the vibrating screen (2) with two screen decks as an exemplary example and the usage of vibrating screen with any number of screen decks as well as other classifiers for grading of the aggregates are well within the scope of the present invention. The vibrating screen (2) of the present invention includes an upper screen deck having an upper screen and a lower screen deck having a lower screen (2b). The aggregates which are in excess of pre-defined size are retained in the upper screen and are fed back to the crushing machine (1) through a recycling conveyor (3) for re-crushing. For illustration, the screens are selected so as to allow the graded aggregates of size 4.75 mm and less through the upper screen and aggregates of size up to 2.5mm through the lower screen. The aggregates which are in size excess of 4.75mm that are retained in the upper screen are fed back to the crushing machine (1) through the recycling conveyor (3) for re-crushing.

While the first graded aggregates, for example of size 2.5mm to 4.75mm are retained by the upper screen are delivered on to a conveyor (4), the second graded aggregates of size for example up to 2.5mm that passes through the lower screen are mixed with water and conveyed to the sand washer (5) through suitable conveying means, for example a pipe (6).

In the sand washer (5) the sand is thoroughly washed by water and the washed sand is fed to the de-watering screen (5a) where the water is removed and the sand with absorbed moisture is delivered to the inlet (7a) of the balancing chute. The regulating arm (7d) is disposed for controlling the quantity of the sand delivered through the first outlet (7b) and the second outlet (7c). The regulated quantity of the sand from the first outlet (7b) of the balancing chute (7) is diverted to first sand conveyor (8), which is used as the first type of sand which is used for plastering application. The regulated quantity of the sand from the second outlet (7c) of the balancing chute (7) is diverted to second sand conveyor (9) .The second sand conveyor (9 also receives the pre determined quantity of graded aggregates from the vibrating screen (2) through the conveyor (4) and the mixture so obtained is used as the second type which is used for concrete mixing.

In one embodiment, the regulating arm (7d) is manually actuated and fastened in the required position. In another embodiment, the regulating arm (7d) is electro mechanically operated using pneumatic cylinder and actuated through compressed air and solenoid valves. In yet another embodiment, the regulating arm (7d) is actuated by a screw rod, the rotation of which is controlled by an electric motor.