Multiwell filter and/or plate

Abstract

A filter plate for use in biological or chemical applications, and its method of manufacture, are disclosed. The filter plate comprises a plurality of structurally interconnected wells which comprise a matrix of wells having a uniform diameter, each well having a side wall which defines a vertically extending, generally cylindrical cavity; a bottom wall which closes the cavity, the bottom wall having a drainage opening formed therein; a filter sheet extending across and resting on top of the bottom wall; the filter sheet being irremovably fixed in position as a result of engagement with the side wall; a conical nozzle having an external surface and an internal passage communicating with the drainage opening in the bottom wall; and a membrane supporting surface across the internal passage extending from the walls of the internal passage to a plane normal to the bottom wall.

What is claimed is:  
     
         1 . A filtration apparatus comprising: 
 a well plate having a plurality of wells, each well extending through said plate, each well having open ends;    an insert having a plurality of counterbores, each counterbore defined by a side wall and a bottom wall, an opening through said bottom wall, each counterbore aligned with a corresponding and respective well from said well plate, said side wall of each counterbore surrounding and bonded to one end of a corresponding well;    a filter disc positioned on said bottom wall of each counterbore and below each said well such that said well compresses the periphery of said filter disc against said bottom wall of said counterbore thereby securing said filter disc in place;    a conical nozzle having an external surface and an internal passage communicating with said opening, said nozzle extending downwardly from said surface of said counterbore from a point radially inward from said well; and    a supporting surface extending across said internal passage.    
     
     
         2 . The filtration apparatus of  claim 1  wherein said internal passage is funnel shaped.  
     
     
         3 . The filtration apparatus of  claim 1  wherein said outer surface of said nozzle intersects said internal passage of said nozzle forming an edge.  
     
     
         4 . The filtration apparatus of  claim 1  further comprising an annular skirt extending from an under surface of said bottom wall of said counterbore and circumscribing said nozzle.  
     
     
         5 . The filtration apparatus of  claim 1  having  96  said interconnected wells.  
     
     
         6 . A filtration apparatus comprising a plurality of structurally interconnected wells which comprise a matrix of wells having a uniform diameter, each well comprising: 
 a) a side wall which defines a vertically extending, generally cylindrical cavity;    b) a bottom wall which closes said cavity, said bottom wall having a drainage opening formed therein;    c) a filter sheet extending across and resting on top of said bottom wall, said filter sheet being irremovably fixed in position as a result of engagement with said side wall;    d) a conical nozzle having an external surface and an internal passage communicating with said drainage opening in said bottom wall, said nozzle extending downwardly from said bottom wall from a point radially inward from said side wall; and    e) a supporting surface across said internal passage extending from the walls of said internal passage to a plane normal to said bottom wall.    
     
     
         7 . The filtration apparatus of  claim 6  wherein said internal passage is funnel shaped.  
     
     
         8 . The filtration apparatus of  claim 6  wherein said external surface intersects said internal passage forming an edge.  
     
     
         9 . The filtration apparatus of  claim 6  further comprising an annular skirt extending from an under surface of said bottom wall and circumscribing said nozzle.  
     
     
         10 . The filtration apparatus of  claim 6  having  96  said interconnected wells.  
     
     
         11 . The filtration apparatus of  claim 6  having  384  said interconnected wells.  
     
     
         12 . A method of making a filter plate comprising the steps of : 
 a) molding an insert having a matrix of counterbores, each counterbore having a bottom wall, an outer rim of predetermined diameter, and an opening therethrough;    b) punching individual filter discs from a filter sheet and pushing said filter discs into a corresponding counterbore such that said filter disc substantially covers the entire bottom wall of the counterbore;    c) molding a well plate against saia insert, said well plate having a top and bottom wall having a matrix of wells of predetermined diameter extending through said plate, each said well having open ends at each of said top corresponds with said matrix of wells such that each said well aligns with a corresponding counterbore, whereby said well fits inside the rim of said counterbore thereby forming a lap joint between each said counterbore and said well, and whereby said well compresses said filter against said bottom wall of said counterbore thereby securing said filter disc in place.    
     
     
         13 . A method of making a filter plate comprising the steps of: 
 a) providing an insert having a matrix of counterbores, each counterbore having a bottom wall and being open at the top,    b) positioning a filter disc in each of said counterbores such that said filter disc rests upon the top surface of said bottom wall, and    c) insert molding a well plate to said insert thereby forming a vertically extending well aligned with each of said counterbores, the side walls of each said well being formed so as to engage each said filter disc.    
     
     
         14 . A method of making a filter plate assembly comprising the steps of: 
 a) providing a molded insert plate of counterbores, said counterbores having a predetermined diameter;    b) placing on said insert plate, a die having a matrix of bores, said bores having a diameter substantially identical to said diameter of said counterbores and arranged such that each bore positionally aligns with a corresponding counterbore;    c) covering said die with a sheet of filter material;    d) positioning above said filter material, a matrix of punch units, each unit positionally aligned with a corresponding bore from said die, each unit comprising a plunger slidably mounted within a cylindrical punch, each punch having a radial cutting bottom edge extending beyond said plunger, each said unit having an outer diameter substantially identical to said diameter of said corresponding bore such that each unit is capable of fitting securely into said corresponding bore    e) depressing said matrix of punch units through said filter material thereby cutting a filter disc from said filter material at each said cutting edge and such that a bottom surface of said plunger contacts said filter disc, said matrix of punch units extending into each said bore such that each said punch unit is at least partially contained within a corresponding bore;    f) extending each said plunger and attached filter disc into contact with each bottom wall of said counterbore of said insert while each said punch remains contained within said bore;    g) depositing each said filter disc on a bottom wall of each respective counterbore;    h) removing each said punch unit from each said counterbore and bore; and    i) fitting a well plate having matrix of open ended wells corresponding in size and location to said counterbores, against said insert such that each well fits securely within each corresponding counterbore.    
     
     
         15 . A method of making a multiwell plate comprising the steps of: 
 a) providing a molded insert plate of rings, said rings each having a substantially flat portion and an annular rim;    b) placing on said insert plate, a die having a matrix of bores, said bores having a diameter substantially identical to said diameter of said rings and arranged such that each bore positionally aligns with a corresponding ring;    c) covering said die with a sheet of material;    d) positioning above said material, a matrix of punch units, each unit positionally aligned with a corresponding bore from said die, each unit comprising a plunger slidably mounted within a cylindrical punch, each punch having a radial cutting bottom edge extending beyond said plunger, each said unit having an outer diameter substantially identical to said diameter of said corresponding bore such that each unit is capable of fitting securely into said corresponding bore    e) depressing said matrix of punch units through said material thereby cutting a disc from said material at each said cutting edge and such that a bottom surface of said plunger contacts said disc, said matrix of punch units extending into each said bore such that each said punch unit is at least partially contained within a corresponding bore;    f) extending each said plunger and attached disc into contact with each flat portion of said ring of said insert while each said punch remains contained within said bore;    g) depositing each said disc on said flat portion of each respective ring;    h) removing each said punch unit from each said counterbore and bore; and    i) molding a well plate having matrix of open ended wells corresponding in size and location to said rings, against said insert such that each well fits securely within each corresponding ring.    
     
     
         16 . A method of making a multiwell plate comprising the steps of: 
 a) providing an insert having a matrix of rings, each ring having an annular support surface around an opening,    b) positioning a disc of material against each said ring such that said disc of material rests upon said support surface,    c) insert molding a well plate to said insert thereby forming a vertically extending well aligned with each of said rings, the side walls of each said well being formed so as to engage each said disc.    
     
     
         17 . A method of making a multiwell plate comprising the steps of: 
 a) molding an insert having a matrix of rings, each ring having a substantially flat support surface and an outer rim of predetermined diameter;    b) punching individual discs from a sheet and pushing said discs into contact with said support surface of a corresponding ring such that said disc substantially covers the entire opening of said ring; and    c) molding a well plate against said insert, said well plate having a top and bottom wall having a matrix of wells of predetermined diameter extending through said plate, each well having open ends at each of said top and bottom wall, said matrix of rings corresponding with said matrix of wells such that each said well aligns with a corresponding ring whereby said well fits inside the rim of said ring thereby forming a lap joint between each said ring and said well, and whereby said well compresses said disk against said support surface of said ring thereby securing said disc in place.    
     
     
         18 . A multiwell plate comprising: 
 a well plate having a plurality of wells, each well extending through said plate, each well having open ends;    an insert having a plurality of rings, each ring having a substantially flat support surface and an outer rim of predetermined diameter, each ring aligned with a corresponding and respective well from said well plate, said outer rim of each ring surrounding and bonded to one end of a corresponding well; and    a disc of material positioned on said support surface of each ring and below each said well such said well compresses the periphery of said disc against said support surface of said ring thereby securing said disc in place.