Title of Invention	A NOVEL UNIQUE QUICK CONTINUOUS SELF-CLEANING STATIONARY YOKED PAIR FRUSTUM VACUUM SIEVES SOLID-LIQUIED SEPARATOR & LIQUID RECYCLER
Abstract	A continuous self-cleaning frustum vacuum sieves solid-liquid separator comprising: two identical conical frustum vacuum filtration vessels (1,2) with filtration bowl (12) adjoined to each other on frustum support legs (18) and yoked by overflow release pipe chute (8); filtrate collection tank (3) with de-liquider drain valve (43) and filtrate backwash pump (4) mounted on said filtrate collection tank (3); said tank is connected with both the frustum vacuum filtration vessel (1,2) and to solid-liquid de-liquider (42) through drain valve (43); receiver hopper (10) with inlet (9) nested in the said first frustum vacuum filtration vessel (1); an inlet releasing pipe chute (11) mounted in the middle of the first frustum vacuum filtration vessel (1); water pump (7) for feeding water to water ring vacuum pump (5) which is connected to the filtrate collection tank (3) for air suction; vacuum flow channels to drain the filtrate through a duct (19) into the outlet (20) regulated by three ports (22,23) actuated ball valve (21); cylindrical vacuum sieve (24) to be lowered in the filtration bath of the said first frustum vacuum filtration vessel (1) open to both sides for filtration and is attached by fasteners to the said hopper (10); and steel fabricated rack (37) with electric geared motor (31), rotating screw (32), moving nut (33), nut guide assembly (34) and proximity switch (36) mounted on it.

Title of Invention

A NOVEL UNIQUE QUICK CONTINUOUS SELF-CLEANING STATIONARY YOKED PAIR FRUSTUM VACUUM SIEVES SOLID-LIQUIED SEPARATOR & LIQUID RECYCLER

Abstract

A continuous self-cleaning frustum vacuum sieves solid-liquid separator comprising: two identical conical frustum vacuum filtration vessels (1,2) with filtration bowl (12) adjoined to each other on frustum support legs (18) and yoked by overflow release pipe chute (8); filtrate collection tank (3) with de-liquider drain valve (43) and filtrate backwash pump (4) mounted on said filtrate collection tank (3); said tank is connected with both the frustum vacuum filtration vessel (1,2) and to solid-liquid de-liquider (42) through drain valve (43); receiver hopper (10) with inlet (9) nested in the said first frustum vacuum filtration vessel (1); an inlet releasing pipe chute (11) mounted in the middle of the first frustum vacuum filtration vessel (1); water pump (7) for feeding water to water ring vacuum pump (5) which is connected to the filtrate collection tank (3) for air suction; vacuum flow channels to drain the filtrate through a duct (19) into the outlet (20) regulated by three ports (22,23) actuated ball valve (21); cylindrical vacuum sieve (24) to be lowered in the filtration bath of the said first frustum vacuum filtration vessel (1) open to both sides for filtration and is attached by fasteners to the said hopper (10); and steel fabricated rack (37) with electric geared motor (31), rotating screw (32), moving nut (33), nut guide assembly (34) and proximity switch (36) mounted on it.

Full Text	FORM - 2 THE PATENTS ACT, 1970 (39 of 1970) COMPLETE SPECIFICATION (See section 10; rule 13) 1. " A Continuous Self-Cleaning Frustum Vacuum Sieves Solid Liquid Separator" 2. (1) (a) Desai Mahesh Balwantrai (b) A-304, Surel Apartments, Near Devashish School, Jadges Bunglow Area, Bodakdev, AHMEDABAD-380054. GUJARAT, INDIA. (c) An Indian. The following specification particularly describes the nature of the invention and the manner in which it is to be performed. GRANTED ORIGINAL 866/MUM/2004 4 FEB 2005 The present invention relates to A Continuous Self-Cleaning Frustum Vacuum Sieves Solid -Liquid Separator It is a common phenomenon in the industrial world to make good use of either only liquid or the solid from, a mixture of free floating solid in a liquid. Accordingly, the sedimentation type solid-liquid separator has been conventionally in wide use in process requiring solid-liquid separation as a part of the manufacturing process in various fields of industries. The manufacturing involves various operations and equipments are applied in preliminary, intermediate or final stages of a process operation. The 'Mass separation' process and equipment form an integral part of the entire gamut. The separation techniques and equipment rely on chemical and physical properties of the substances processed. Absorption, adsorption, solvent extraction and membrane technology are unit operations aimed at 'MASS SEPARATION', relying on chemical properties and concentration driving forces. Physical separation technologies* and equipment are called "Mechanical Separation" equipment and capitalize on properties such as density, viscosity, surface tension, electrostatic forces, size and several other properties, whereby the differences between the components and in some cases the phases of components are significant. The "Mechanical Separation" equipment are used for either processing intermediate products, product separation or recovery, for improving feed and product stream qualities and purities and for pollution control purposes. These equipments category may be used to separate solids or particulate matter from liquids, slurries and gases to concentrate solids by removing moisture through means other than by the direct application of thermal energy to segregate solid particle matter by size or density differences to separate liquids by means other than solvent extraction or distillation. The mechanical separators are therefore categorized as filtration, floatation and clarification, centrifugation, particle segregation and classification and setting or sedimentation equipment. Such conventional sedimentation type solid-liquid separators, there is such a problem that the separation time of the clear liquid from slurry/mixture becomes considerably long. Also down- sizing of the separator or higher production efficiency cannot be expected resulting in the increase of the facility investment and the operation cost. The equipment used in liquid filtration applications fall into three general operational modes based on the differences in orientation between gravity force and filtrate motion. These orientations are forces acting in the opposite direction (countercurrent), forces acting in the same direction (concurrent) and forces acting normal to each other (cross - flow). Solid - liquid separation is a fundamental unit operation that exists in almost every flow scheme related to the chemical process industries, ore beneficiation, pharmaceutics, food or drinking water and wastewater treatment. The separation techniques are very diverse. As a unit operation, there are many types of equipment that are used not just filtration systems. In addition to filtration by such equipment as vacuum and pressure filters, there are centrifugation by filtering and sedimenting centrifuges, sedimentation by conventional, storage and high rate thickeners, clarification by conventional, solid - contact and sludge -blanket clarifiers, polishing by pre-coat filters, pressure and deep - bed filters and upward separation by dissolved - air flotation. Once the solid is separated it requires washing and drying and converted into free flowing powder. Thus, broadly classifying, various operations basically fall into two categories i.e. initial mechanized liquid filtration and subsequent treatment of separated solid. These filters use a filtering medium or a septum that retains the solid and passes the liquid through due to positive atmospheric pressure towards the other side where negative pressure is generated due to vacuum suction. In the typical operation the retained solid in the form of cake gradually builds on the surface of filtering medium or septum and the resistance to liquid flow to pass through progressively increases. Thus, if the filtration pressure is constant, the rate of flow of liquid progressively diminishes whereas, if the liquid flow rate is to be maintained constant, the pressure must be gradually increased. For any filtration pressure, the rate of filtrate flow is greatest at the beginning of the process since the resistance is then at the minimum due to clean filter medium and little formation of solid cake. The initial higher rates of filtration result into quickly plugging of the pores of the filter medium and cause increasing resistance and build up of pressure. The higher pressures starts exerting on the body of the filter medium and further narrow the passages in the weave of the cloth reducing filtrate flow. This process of reducing filtrate flow and increasing pressure even after mechanized scrapping and removal of the cake can not be avoided and the filter medium thorough washing or replacement is required suspending production activity. To over come immediate washing or replacement, vacuum filters normally have very large filter medium surface area, which is again a major handicap and the orientation of the solid particles in the initial can appreciably influence the structure of the cake and the resistance it develops. Build up of solid in the cake form has large effect on the flow resistance and seriously affect the useful life of the filter medium. To overcome such limitations "A Continuous Self-Cleaning Frustum Vacuum Sieves Solid -Liquid Separator" is invented. It has a unique design such with lower capital investment and the production cost significantly, saves production time, enhances capacity, keeps the solid far from getting contaminated as the process becomes continuous and human intervention is not required. The present invention will be described with greater specific reference to the following drawing. Fig. 1 represents cross - sectional view of a A Continuous Self-Cleaning Frustum Vacuum Sieves Solid -Liquid Separator The system consists of yoked pair identical frustum vacuum filtration vessels 1 & 2, filtrate collection tank 3 on which filtrate backwash pump 4 is mounted and water-ring vacuum pump 5 which is mounted on water tank 6. The water pump 7 feeds water to the vacuum pump. The pair of the frustum vacuum filtration vessels is yoked by overflow release pipe chute 8. The overflow release pipe chute releases mixture from the first vessel to the second vessel. The mixture from which the liquid and the solid are required to be separated, is poured or fed through the inlet 9 into the receiver hopper 10 nested in the first frustum vacuum filtration vessel 1. The mixture received into the hopper is restricted but released in the bottom of the first frustum vacuum filtration vessel l's filtration bowl through an inlet releasing pipe chute 11. The filtration bowl in both the filtration vessels are formed by filtration bags 12 made of suitable filter cloth. The bags are open from the top to receive the mixture and also open from the bottom to discharge the separated solid. The top of the bag is held in position by the top lock 13 and the bottom is held in position by the bottom lock 14. These bags rest on rigid wire mesh support 15 to retain their shape. These filtration bags are also in circular cone, polygon and hexagonal shape depends on the frustum vessel's shape. The atmospheric pressure is withstood by the metal ribs 16 which support the rigid wire mesh and also form vacuum chamber and filtrate flow channels. These metal ribs are welded to the frustum vacuum filtration vessels' metal wall 17. Between the wire mesh and the conical metal wall of the frustum vessels, vacuum flow channels are formed due to the welded ribs. The structure's support legs 18 are fixed to the metal wall and make the frustums stand firmly on the ground. The vacuum flow channels drain the filtrate through a duct 19 into the outlet 20 regulated by three ports actuated (pneumatic, hydraulic or motorized) ball valve 21. The valve's port towards filtrate outlet always remains open. The remaining two ports open one after the other as required. One of the ports 22 opens towards filtrate drain and the other port 23 opens to receive backwash filtrate. The mixture released in the bottom portion of the filtration bowl of the first frustum vacuum filtration vessel forms a bath. As the filtrate drain valve port is open and vacuum suction is applied, the pressure in the filtrate flow channels decreases and the positive atmospheric pressure forces the liquid in the mixture to get filtered through the filter cloth bag, leaving behind the solid deposited on the cloth surface. The clear filtrate drains out through the valve. The free floating solid particles in the mixture bath are subjected to a dragging force because of the liquid being sucked through the filter cloth and quickly start settling to form a cake on the filter cloth. The cake formation starts from the bottom portion of the bowl and gradually rises to the top of the frustum vacuum filtration vessel with the rising bath level. There is also a cylindrical vacuum sieve 24 open to both sides for filtration, lowered in the filtration bath of the first frustum vacuum filtration vessel and attached by fasteners to the hopper. The filtrate flow channels are formed the same way using rigid wire mesh and metal ribs. The filtrate outlet is connected to the frustum vacuum filtration vessel's drain duct by flexible pipes 25. The liquid also gets filtered due to vacuum suction from this cylindrical sieve. However, the solid cake deposition on the cloth does not thicken attached to the cloth but falls down due to its dead weight, giving clean filter cloth for long time, augmenting desired filtration rate. The filtrate again drains out through the valve. The combined effect of the filtration in the first frustum vacuum filtration vessel 1 on the cake formation is such that the thickness of the cake in the bottom is more where the filtration surface area is smaller than the thickness at the top of the vessel where the filtration surface area is quite large. Thus the rate of filtration remains constant at low pressure for longer time duration. Gradually the level of the mixture bath in the filtration vessel 1 rises upto the top and the overflow of the mixture starts from the filtration vessel 1 to the filtration vessel 2 through the overflow release yoke where it is received into the overflow receiver and distributor trough 26. The mixture received here has very low content of solid as most of the solid can not rise the whole height of the first frustum vacuum filtration vessel and overflow crossing the resistance developed by the cylindrical vacuum sieve. The trough distributes the mixture in such a way that it runs down the filtering surface from the top circular periphery towards the bottom of the second frustum filtration vessel. The valve is open towards vacuum suction and liquid gets filtered due to positive atmospheric pressure. The solid is deposited on the cloth's surface; however, no noticeable cake forming takes place due to constant washing by the running mixture. A shallow bath forms in the filtration bowl and the filtration rate is maintained. The continuously pouring mixture and separation of solid increases the build up of cake formation on the filter cloth and it becomes necessary to remove the separated solid and clean the filter cloth. The removed solid also requires to be discharged out of the system. The solid removal involves backwashing of the filter cloth. However, before the backwash is carried out, the system is prepared to manage the removal of the solid out of the filtration system. The frustum vacuum filtration vessels have at the bottom solid discharge chute pipe 27 inserted from the center of the filtrate drain duct and welded to the metal ribs. The solid discharge chute is held in position due the grip of the drain duct's welded outer metal body, which in turn is welded to the conical metal wall of the frustum vacuum filtration vessel. The top mouth and bottom discharge of the solid discharge pipe chute are controlled by top lid 28 and bottom lid 29 connected by a fixed ^distance piece 30. Both the lids have rubber rims to prevent liquid leakage. The bottom lid has inverted cone cap for easy sliding of discharged solid slurry. These lids are pulled up or pushed down by the forward/reverse electric geared motor 31. The electric motor is connected to a rotating screw 32 on which a moving nut 33 slides up or down as per the rotation of the screw. The moving nut is held in position by two guides 34 fixed on both the sides. The nut has limit arm 35 welded on it for the proximity switch 36 to sense the normal position of the nut on the screw. The geared electric motor, rotating screw, moving nut and the nut guides assembly is mounted on steel fabricated rack 37. The nut has lifting arms 38, and attached to it at the bottom is a distance piece 39 welded to the top lid. When the electric motor is switched on the screw rotates and the nut moves up or down depending upon the motor's forward or reverse motion. Along with the nut the lifting arms either lift up or push down the distance piece, the top lid and the bottom lid. The entire mechanical arrangement makes it possible to discard separated solid in thick slurry form through the bottom solid discharge chute pipe out of the frustum vacuum vessel by a self cleaning process so that the filtrate flow rate continues at the desired level uninterruptedly. The various operations are controlled by a PLC. The separated solid evacuation involves backwashing the filter cloth by injecting clear filtrate back into the filtrate drain flow channels by a backwash pump. However, before starting backwash, the evacuation system is readied to manage the separated solid. The solid evacuation system's electric motor is rotated so that the moving nut and the lifting arms pull up the top lid to open the bottom solid discharge chute pipe's mouth to receive separated solid cake. The lids' upward travel is stopped by the proximity switch sensor 40 counting the teeth of the rotating control sprocket 41 As soon as the sprocket's teeth count suggests linear distance upward travel; the power supply to the motor is cut off. Now, the filtrate drain port of the valve is closed and the backwash receiving port is opened. The filtrate backwash pump is switched on and the backwash is injected through the valve into the drain outlet. The backwash filtrate starts rising into the vacuum chamber from the bottom in the filtrate flow channels and increase pressure from the inside to the out side of the filter cloth where the solid is deposited in the form of cake. As the filtrate penetrates the pores of the filter cloth and comes out pushing the solid cake which slides down into the mouth of the solid discharge chute pipe. The filtrate backwash continues for predetermined time, after which the backwash pump is shut off. The backwash receiving port is closed and the filtrate drain port is opened. The filtrate drain now resumes. The electric motor is rotated in the reverse direction so that the moving nut and the lifting arms push down the top lid and close the mouth of the solid discharge chute pipe. The solid cake in the solid discharge chute pipe settles down. The process of backwash is repeated at certain interval necessitated by the quantum of solid particles being poured in the system with the mixture and cake formation on the filter cloth, which is indicated by the rising vacuum in the system. The backwash is thus actually carried out at the predetermined vacuum pressure beyond which it is not permitted to rise. After calculated number of backwashes, the solid discharge chute pipe fills up and requires to be emptied. The electric motor is switched on and rotated in such a direction that the moving nut and the lifting arms push down the top lid and the bottom lid. The bottom lid comes out of the chute pipe and opens the bottom discharge. The electric motor is stopped when the teeth count of the sprocket by the proximity sensor suggests the linear downward motion of the lids. The solid in the slurry form slide easily out on top of the inverted cone cap of the bottom lid into the bath of solid de-liquider 42. The electric motor is now rotated in the reverse direction so that both lids retract back to their original position and close the bottom discharge. The liquid drain valve 43 of the de-liquider is opened and vacuum suction is applied. The liquid that has escaped with the solid is reintroduced into the system. The valve is closed and the scrappers 44 are moved to dump the solid into the screw conveyor 45 to discard the solid. This single equipment can be used replacing all multiple processes where liquid-solid separation is required for either retrieving or recycling liquid or obtaining solid in cake form directly from slurry or mixture. This equipment has novel & unique design so; it performs efficient liquid filtration, solid separation and further process in one stage instead of batches. Also the solid delivery mechanical arrangement provides better flexibility for delivering dried powder at a desired place within the length of the screw conveyor.

Full Text

FORM - 2
THE PATENTS ACT, 1970
(39 of 1970) COMPLETE SPECIFICATION
(See section 10; rule 13)
1. " A Continuous Self-Cleaning Frustum Vacuum Sieves Solid
Liquid Separator"
2. (1) (a) Desai Mahesh Balwantrai
(b) A-304, Surel Apartments,
Near Devashish School,
Jadges Bunglow Area,
Bodakdev,
AHMEDABAD-380054. GUJARAT, INDIA.
(c) An Indian.
The following specification particularly describes the nature of the invention and the manner in which it is to be performed.
GRANTED

ORIGINAL
866/MUM/2004

4 FEB 2005

The present invention relates to A Continuous Self-Cleaning Frustum Vacuum Sieves Solid -Liquid Separator
It is a common phenomenon in the industrial world to make good use of either only liquid or the solid from, a mixture of free floating solid in a liquid. Accordingly, the sedimentation type solid-liquid separator has been conventionally in wide use in process requiring solid-liquid separation as a part of the manufacturing process in various fields of industries. The manufacturing involves various operations and equipments are applied in preliminary, intermediate or final stages of a process operation. The 'Mass separation' process and equipment form an integral part of the entire gamut. The separation techniques and equipment rely on chemical and physical properties of the substances processed. Absorption, adsorption, solvent extraction and membrane technology are unit operations aimed at 'MASS SEPARATION', relying on chemical properties and concentration driving forces. Physical separation technologies* and equipment are called "Mechanical Separation" equipment and capitalize on properties such as density, viscosity, surface tension, electrostatic forces, size and several other properties, whereby the differences between the components and in some cases the phases of components are significant. The "Mechanical Separation" equipment are used for either processing intermediate products, product separation or recovery, for improving feed and product stream qualities and purities and for pollution control purposes. These equipments category may be used to separate solids or particulate matter from liquids, slurries and gases to concentrate solids by removing moisture through means other than by the direct application of thermal energy to segregate solid

particle matter by size or density differences to separate liquids by means other than solvent extraction or distillation. The mechanical separators are therefore categorized as filtration, floatation and clarification, centrifugation, particle segregation and classification and setting or sedimentation equipment. Such conventional sedimentation type solid-liquid separators, there is such a problem that the separation time of the clear liquid from slurry/mixture becomes considerably long. Also down- sizing of the separator or higher production efficiency cannot be expected resulting in the increase of the facility investment and the operation cost. The equipment used in liquid filtration applications fall into three general operational modes based on the differences in orientation between gravity force and filtrate motion. These orientations are forces acting in the opposite direction (countercurrent), forces acting in the same direction (concurrent) and forces acting normal to each other (cross - flow). Solid - liquid separation is a fundamental unit operation that exists in almost every flow scheme related to the chemical process industries, ore beneficiation, pharmaceutics, food or drinking water and wastewater treatment. The separation techniques are very diverse. As a unit operation, there are many types of equipment that are used not just filtration systems. In addition to filtration by such equipment as vacuum and pressure filters, there are centrifugation by filtering and sedimenting centrifuges, sedimentation by conventional, storage and high rate thickeners, clarification by conventional, solid - contact and sludge -blanket clarifiers, polishing by pre-coat filters, pressure and deep - bed filters and upward separation by dissolved - air flotation. Once the solid is separated it requires washing and drying and converted into free flowing powder. Thus, broadly classifying, various operations basically fall into two categories i.e. initial mechanized liquid filtration and subsequent treatment

of separated solid. These filters use a filtering medium or a septum that retains the solid and passes the liquid through due to positive atmospheric pressure towards the other side where negative pressure is generated due to vacuum suction. In the typical operation the retained solid in the form of cake gradually builds on the surface of filtering medium or septum and the resistance to liquid flow to pass through progressively increases. Thus, if the filtration pressure is constant, the rate of flow of liquid progressively diminishes whereas, if the liquid flow rate is to be maintained constant, the pressure must be gradually increased. For any filtration pressure, the rate of filtrate flow is greatest at the beginning of the process since the resistance is then at the minimum due to clean filter medium and little formation of solid cake. The initial higher rates of filtration result into quickly plugging of the pores of the filter medium and cause increasing resistance and build up of pressure. The higher pressures starts exerting on the body of the filter medium and further narrow the passages in the weave of the cloth reducing filtrate flow. This process of reducing filtrate flow and increasing pressure even after mechanized scrapping and removal of the cake can not be avoided and the filter medium thorough washing or replacement is required suspending production activity. To over come immediate washing or replacement, vacuum filters normally have very large filter medium surface area, which is again a major handicap and the orientation of the solid particles in the initial can appreciably influence the structure of the cake and the resistance it develops. Build up of solid in the cake form has large effect on the flow resistance and seriously affect the useful life of the filter medium. To overcome such limitations "A Continuous Self-Cleaning Frustum Vacuum Sieves Solid -Liquid Separator" is invented. It has a unique

design such with lower capital investment and the production cost significantly, saves production time, enhances capacity, keeps the solid far from getting contaminated as the process becomes continuous and human intervention is not required.
The present invention will be described with greater specific reference to the following drawing.
Fig. 1 represents cross - sectional view of a A Continuous Self-Cleaning
Frustum Vacuum Sieves Solid -Liquid Separator
The system consists of yoked pair identical frustum vacuum filtration vessels 1 & 2, filtrate collection tank 3 on which filtrate backwash pump 4 is mounted and water-ring vacuum pump 5 which is mounted on water tank 6. The water pump 7 feeds water to the vacuum pump. The pair of the frustum vacuum filtration vessels is yoked by overflow release pipe chute 8. The overflow release pipe chute releases mixture from the first vessel to the second vessel.
The mixture from which the liquid and the solid are required to be separated, is poured or fed through the inlet 9 into the receiver hopper 10 nested in the first frustum vacuum filtration vessel 1. The mixture received into the hopper is restricted but released in the bottom of the first frustum vacuum filtration vessel l's filtration bowl through an inlet releasing pipe chute 11.

The filtration bowl in both the filtration vessels are formed by filtration bags 12 made of suitable filter cloth. The bags are open from the top to receive the mixture and also open from the bottom to discharge the separated solid. The top of the bag is held in position by the top lock 13 and the bottom is held in position by the bottom lock 14. These bags rest on rigid wire mesh support 15 to retain their shape. These filtration bags are also in circular cone, polygon and hexagonal shape depends on the frustum vessel's shape. The atmospheric pressure is withstood by the metal ribs 16 which support the rigid wire mesh and also form vacuum chamber and filtrate flow channels. These metal ribs are welded to the frustum vacuum filtration vessels' metal wall 17. Between the wire mesh and the conical metal wall of the frustum vessels, vacuum flow channels are formed due to the welded ribs. The structure's support legs 18 are fixed to the metal wall and make the frustums stand firmly on the ground. The vacuum flow channels drain the filtrate through a duct 19 into the outlet 20 regulated by three ports actuated (pneumatic, hydraulic or motorized) ball valve 21.
The valve's port towards filtrate outlet always remains open. The remaining two ports open one after the other as required. One of the ports 22 opens towards filtrate drain and the other port 23 opens to receive backwash filtrate.
The mixture released in the bottom portion of the filtration bowl of the first frustum vacuum filtration vessel forms a bath. As the filtrate drain valve port is open and vacuum suction is applied, the pressure in the filtrate flow channels decreases and the positive atmospheric pressure

forces the liquid in the mixture to get filtered through the filter cloth bag, leaving behind the solid deposited on the cloth surface. The clear filtrate drains out through the valve.
The free floating solid particles in the mixture bath are subjected to a dragging force because of the liquid being sucked through the filter cloth and quickly start settling to form a cake on the filter cloth. The cake formation starts from the bottom portion of the bowl and gradually rises to the top of the frustum vacuum filtration vessel with the rising bath level.
There is also a cylindrical vacuum sieve 24 open to both sides for filtration, lowered in the filtration bath of the first frustum vacuum filtration vessel and attached by fasteners to the hopper. The filtrate flow channels are formed the same way using rigid wire mesh and metal ribs. The filtrate outlet is connected to the frustum vacuum filtration vessel's drain duct by flexible pipes 25. The liquid also gets filtered due to vacuum suction from this cylindrical sieve. However, the solid cake deposition on the cloth does not thicken attached to the cloth but falls down due to its dead weight, giving clean filter cloth for long time, augmenting desired filtration rate. The filtrate again drains out through the valve.
The combined effect of the filtration in the first frustum vacuum filtration vessel 1 on the cake formation is such that the thickness of the cake in the bottom is more where the filtration surface area is smaller than the thickness at the top of the vessel where the filtration surface area is quite

large. Thus the rate of filtration remains constant at low pressure for longer time duration.
Gradually the level of the mixture bath in the filtration vessel 1 rises upto the top and the overflow of the mixture starts from the filtration vessel 1 to the filtration vessel 2 through the overflow release yoke where it is received into the overflow receiver and distributor trough 26. The mixture received here has very low content of solid as most of the solid can not rise the whole height of the first frustum vacuum filtration vessel and overflow crossing the resistance developed by the cylindrical vacuum sieve. The trough distributes the mixture in such a way that it runs down the filtering surface from the top circular periphery towards the bottom of the second frustum filtration vessel. The valve is open towards vacuum suction and liquid gets filtered due to positive atmospheric pressure. The solid is deposited on the cloth's surface; however, no noticeable cake forming takes place due to constant washing by the running mixture. A shallow bath forms in the filtration bowl and the filtration rate is maintained.
The continuously pouring mixture and separation of solid increases the build up of cake formation on the filter cloth and it becomes necessary to remove the separated solid and clean the filter cloth. The removed solid also requires to be discharged out of the system.
The solid removal involves backwashing of the filter cloth. However, before the backwash is carried out, the system is prepared to manage the removal of the solid out of the filtration system. The frustum vacuum

filtration vessels have at the bottom solid discharge chute pipe 27 inserted from the center of the filtrate drain duct and welded to the metal ribs. The solid discharge chute is held in position due the grip of the drain duct's welded outer metal body, which in turn is welded to the conical metal wall of the frustum vacuum filtration vessel. The top mouth and bottom discharge of the solid discharge pipe chute are controlled by top lid 28 and bottom lid 29 connected by a fixed ^distance piece 30. Both the lids have rubber rims to prevent liquid leakage. The bottom lid has inverted cone cap for easy sliding of discharged solid slurry. These lids are pulled up or pushed down by the forward/reverse electric geared motor 31. The electric motor is connected to a rotating screw 32 on which a moving nut 33 slides up or down as per the rotation of the screw. The moving nut is held in position by two guides 34 fixed on both the sides. The nut has limit arm 35 welded on it for the proximity switch 36 to sense the normal position of the nut on the screw. The geared electric motor, rotating screw, moving nut and the nut guides assembly is mounted on steel fabricated rack 37. The nut has lifting arms 38, and attached to it at the bottom is a distance piece 39 welded to the top lid. When the electric motor is switched on the screw rotates and the nut moves up or down depending upon the motor's forward or reverse motion. Along with the nut the lifting arms either lift up or push down the distance piece, the top lid and the bottom lid.
The entire mechanical arrangement makes it possible to discard separated solid in thick slurry form through the bottom solid discharge chute pipe out of the frustum vacuum vessel by a self cleaning process so that the

filtrate flow rate continues at the desired level uninterruptedly. The various operations are controlled by a PLC.
The separated solid evacuation involves backwashing the filter cloth by injecting clear filtrate back into the filtrate drain flow channels by a backwash pump. However, before starting backwash, the evacuation system is readied to manage the separated solid.
The solid evacuation system's electric motor is rotated so that the moving nut and the lifting arms pull up the top lid to open the bottom solid discharge chute pipe's mouth to receive separated solid cake. The lids' upward travel is stopped by the proximity switch sensor 40 counting the teeth of the rotating control sprocket 41 As soon as the sprocket's teeth count suggests linear distance upward travel; the power supply to the motor is cut off.
Now, the filtrate drain port of the valve is closed and the backwash receiving port is opened. The filtrate backwash pump is switched on and the backwash is injected through the valve into the drain outlet. The backwash filtrate starts rising into the vacuum chamber from the bottom in the filtrate flow channels and increase pressure from the inside to the out side of the filter cloth where the solid is deposited in the form of cake. As the filtrate penetrates the pores of the filter cloth and comes out pushing the solid cake which slides down into the mouth of the solid discharge chute pipe. The filtrate backwash continues for predetermined time, after which the backwash pump is shut off. The backwash receiving

port is closed and the filtrate drain port is opened. The filtrate drain now resumes.
The electric motor is rotated in the reverse direction so that the moving nut and the lifting arms push down the top lid and close the mouth of the solid discharge chute pipe. The solid cake in the solid discharge chute pipe settles down.
The process of backwash is repeated at certain interval necessitated by the quantum of solid particles being poured in the system with the mixture and cake formation on the filter cloth, which is indicated by the rising vacuum in the system. The backwash is thus actually carried out at the predetermined vacuum pressure beyond which it is not permitted to rise.
After calculated number of backwashes, the solid discharge chute pipe fills up and requires to be emptied. The electric motor is switched on and rotated in such a direction that the moving nut and the lifting arms push down the top lid and the bottom lid. The bottom lid comes out of the chute pipe and opens the bottom discharge. The electric motor is stopped when the teeth count of the sprocket by the proximity sensor suggests the linear downward motion of the lids. The solid in the slurry form slide easily out on top of the inverted cone cap of the bottom lid into the bath of solid de-liquider 42.
The electric motor is now rotated in the reverse direction so that both lids retract back to their original position and close the bottom discharge.

The liquid drain valve 43 of the de-liquider is opened and vacuum suction is applied. The liquid that has escaped with the solid is reintroduced into the system. The valve is closed and the scrappers 44 are moved to dump the solid into the screw conveyor 45 to discard the solid.
This single equipment can be used replacing all multiple processes where liquid-solid separation is required for either retrieving or recycling liquid or obtaining solid in cake form directly from slurry or mixture. This equipment has novel & unique design so; it performs efficient liquid filtration, solid separation and further process in one stage instead of batches. Also the solid delivery mechanical arrangement provides better flexibility for delivering dried powder at a desired place within the length of the screw conveyor.

Documents:

866-mum-2004-cancelled pages(14-2-2005).pdf

866-mum-2004-claims(granted)-(14-2-2005).doc

866-mum-2004-claims(granted)-(14-2-2005).pdf

866-mum-2004-correspondence(26-9-2006).pdf

866-mum-2004-correspondence(ipo)-(31-12-2004).pdf

866-mum-2004-drawing(14-2-2005).pdf

866-mum-2004-form 1(11-8-2004).pdf

866-mum-2004-form 1(7-8-2004).pdf

866-mum-2004-form 19(18-8-2004).pdf

866-mum-2004-form 2(granted)-(14-2-2005).doc

866-mum-2004-form 2(granted)-(14-2-2005).pdf

866-mum-2004-form 26(7-8-2004).pdf

866-mum-2004-form 3(8-2-2005).pdf

866-mum-2004-form 5(7-8-2004).pdf

866-mum-2004-form 8(25-7-2007).pdf

866-mum-2004-form 8(25-9-2006).pdf

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Patent Number

208362

Indian Patent Application Number

866/MUM/2004

PG Journal Number

42/2008

Publication Date

17-Oct-2008

Grant Date

25-Jul-2007

Date of Filing

11-Aug-2004

Name of Patentee

DESAI MAHESH BALWANTRAI

Applicant Address

A-304, SUREL APARTMENTS, NEAR DEVASHISH SCHOOL, JADGES BUNGLOW AREA, BODAKDEV, AHMEDABAD 380054. GUJARAT, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	DESAI MAHESH BALWANTRAI	A-304, SUREL APARTMENTS, NEAR DEVASHISH SCHOOL, JADGES BUNGLOW AREA, BODAKDEV, AHMEDABAD - 380054. GUJARAT, INDIA.

PCT International Classification Number

B01D 29/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA