Chromatographic device and method of forming a chromatographic device

Abstract

A chromatographic device comprises a tube, a chromatographic medium, a piston assembly, and a locking mechanism. The tube comprises first and second opposite ends and an inner surface. The inner surface of the tube at least in part defines an intermediate region. The intermediate region is generally between the first and second ends. The chromatographic medium is within the intermediate region. The piston assembly is within the tube and is positioned generally between the first end of the tube and the chromatographic medium. The piston assembly defines a passage for flow of process fluid. The piston assembly comprises a piston body portion. The locking mechanism is adjacent the piston assembly and is in engagement with the inner surface of the tube in a manner to prevent movement of the piston assembly relative to the tube axially toward the first end of the tube without preventing movement of the piston assembly relative to the tube axially toward the second end of the tube.

1 . A chromatographic device comprising: 
 a tube extending longitudinally along a tube axis, the tube comprising first and second opposite ends, and an inner surface, the inner surface of the tube at least in part defining an intermediate region, the intermediate region being generally between the first and second ends;    a chromatographic medium within the intermediate region;    a piston assembly within the tube and positioned generally between the first end of the tube and the chromatographic medium, the piston assembly defining a passage for flow of process fluid, the piston assembly comprising a piston body portion;    a frit generally between the piston body portion and the chromatographic medium;    a flexible sleeve engaging both the piston body portion and the frit; and    a locking body portion adjacent the piston body portion, and wherein:    the locking body portion has an outer surface and a shoulder surface, the outer surface defining a peripheral boundary lying in a plane perpendicular to the tube axis, the shoulder surface being radially inward of the peripheral boundary; and    the tube is crimped such that the inner surface of the tube includes a locking body engaging surface portion operatively engaging the shoulder surface of the locking body portion in a manner to prevent the piston assembly from moving axially toward the first end of the tube, the locking body engaging surface portion being radially inward of the peripheral boundary.    
   
   
       2 . A chromatographic device as set forth in  claim 1  wherein the flexible sleeve comprises a polymeric material and circumscribes the frit and an end margin of the piston body portion.  
   
   
       3 . A chromatographic device as set forth in  claim 2  wherein the flexible sleeve is of a heat-shrinkable material.  
   
   
       4 . A chromatographic device as set forth in  claim 3  wherein the flexible sleeve is heat shrunk on the frit and end margin of the piston body portion to form a snug fit of the sleeve around the frit and end margin of the piston body portion.  
   
   
       5 . A chromatographic device as set forth in  claim 1  wherein the polymeric material comprises polytetrafluoroethylene.  
   
   
       6 . A chromatographic device comprising: 
 a tube extending longitudinally along a tube axis, the tube comprising first and second opposite ends, and an inner surface, the inner surface of the tube at least in part defining an intermediate region, the intermediate region being generally between the first and second ends;    a chromatographic medium within the intermediate region;    a piston assembly within the tube and positioned generally between the first end of the tube and the chromatographic medium, the piston assembly defining a passage for flow of process fluid, the piston assembly comprising a piston body portion;    a locking body portion having an outer surface and a shoulder surface, the outer surface defining a peripheral boundary lying in a plane perpendicular to the tube axis, the shoulder surface being radially inward of the peripheral boundary;    the tube being crimped such that the inner surface includes a locking body engaging surface portion operatively engaging the shoulder surface of the locking body portion in a manner to prevent the piston assembly from moving axially toward the first end of the tube, the locking body engaging surface portion being radially inward of the peripheral boundary.    
   
   
       7 . A chromatographic device as set forth in  claim 6  wherein the piston assembly comprises a first piston assembly and the locking body portion comprises a first locking body portion and wherein the chromatographic device further comprises a second piston assembly and a second locking body portion within the tube and positioned generally between the second end of the tube and the chromatographic medium, the second piston assembly defining a second passage for flow of process fluid, the second piston assembly comprising a second piston body portion, the second locking body portion having a second outer surface and a second shoulder surface, the second outer surface defining a second peripheral boundary lying in a plane perpendicular to the tube axis, the second shoulder surface being radially inward of the second peripheral boundary, the tube being crimped such that the inner surface includes a second locking body engaging surface portion operatively engaging the second shoulder surface of the second locking body portion in a manner to prevent the second piston assembly from moving axially toward the second end of the tube, the second piston engaging surface portion being radially inward of the peripheral boundary.  
   
   
       8 . A chromatographic device as set forth in  claim 6  wherein the piston assembly further comprises a frit and a flexible sleeve, the flexible sleeve engaging both the piston body portion and the frit, the frit being generally between the piston body portion and the chromatographic medium.  
   
   
       9 . A chromatographic device as set forth in  claim 8  wherein the flexible sleeve comprises a polymeric material.  
   
   
       10 . A chromatographic device as set forth in  claim 6  further comprising a line connector within the tube and between the piston body portion and the first end of the tube, the line connector being adhered to the inner surface of the tube, the line connector being adapted for connection thereto of a fluid supply line for passage of process fluid, the line connector and the piston body portion being separate members.  
   
   
       11 . A chromatographic device as set forth in  claim 10  wherein the line connector is of a material different than that of the piston body portion.  
   
   
       12 . A chromatographic device as set forth in  claim 7 , further comprising: 
 a first line connector within the tube and between the first piston body portion and the first end of the tube, the first line connector and the first piston body portion being separate members; and    a second line connector within the tube and between the second piston body portion and the second end of the tube, the second line connector and the second piston body portion being separate members;    the first line connector being adapted for connection thereto of a fluid feed line and the second line connector being adapted for connection thereto of a fluid discharge line.    
   
   
       13 . A chromatographic device as set forth in  claim 12  wherein the first and second line connectors are adhered to the inner surface of the tube.  
   
   
       14 . A chromatographic device as set forth in  claim 12  wherein the first line connector is of a material different than that of the first piston body portion and the second line connector is of a material different that that of the second piston body portion.  
   
   
       15 . A method of forming a chromatographic device comprising: 
 providing a tube having a primary end, a secondary end margin defining a secondary end opposite the primary end, and an inner surface, the tube extending longitudinally along a tube axis;    providing a piston assembly;    placing a chromatographic medium in the tube and inserting the piston assembly into the tube such that the piston assembly is between the chromatographic medium and the secondary end;    moving the piston assembly along the tube axis and toward the primary end such that the piston assembly is between the secondary end margin and the chromatographic medium; and    removing the secondary end margin of the tube from rest of the tube; the removing step occurring after the moving step.    
   
   
       16 . A method as set forth in  claim 15  wherein the moving step causes compression of the chromatographic medium.  
   
   
       17 . A method as set forth in  claim 15  further comprising: 
 operatively locking the piston assembly to the inner surface of the tube to impede movement of the piston assembly relative to the tube toward the secondary end margin of the tube;    the locking step occurring between the moving step and the removing step.    
   
   
       18 . A method as set forth in  claim 15  further comprising providing a locking body portion adjacent the piston assembly, the locking body portion having an outer surface and a shoulder surface, the outer surface defining a peripheral boundary lying in a plane perpendicular to the tube axis, the shoulder surface being radially inward of the peripheral boundary; and 
 the locking step comprises crimping the tube such that the inner surface of the tube forms a locking body engaging surface portion operatively engaging the shoulder surface of the locking body portion to prevent the piston assembly from moving axially toward the secondary end margin of the tube, the locking body engaging surface portion being radially inward of the peripheral boundary.    
   
   
       19 . A method as set forth in  claim 15  wherein: 
 the step of providing a piston assembly comprises providing a piston assembly having a piston body portion; and    the locking step comprises inserting a locking mechanism in the tube and adjacent the piston assembly, the locking mechanism engaging the inner surface of the tube in a manner to prevent movement of the piston assembly relative to the tube axially toward the secondary end margin of the tube without preventing movement of the piston assembly relative to the tube axially toward the primary end of the tube.    
   
   
       20 . A method as set forth in  claim 15  wherein the step of providing a piston assembly comprises providing a second piston assembly and wherein the method further comprises: 
 providing a first piston assembly;    inserting the first piston assembly into the tube such that the first piston assembly is between the chromatographic medium and the primary end; and    operatively locking the first piston assembly to the inner surface of the tube to impede movement of the piston assembly relative to the tube toward the primary end of the tube.