Press for removing supernatant from a flexible vessel

Abstract

A press for removing supernatant from a flexible vessel includes cooperating press members having an open position to insert the vessel between them, and a closed position to compress the vessel between them. At least one of the press members has a compliant pad on its press surface. The compliant pad compensates for variable thickness of the vessel when it is compressed. The press is constructed to compress a first or lower portion of the vessel less than a second or upper portion of the vessel. Preferably, the press additionally includes a barrier structure that creates a barrier between the lower portion of the vessel and the upper portion of the vessel when the vessel is compressed. The press can also include a vessel holder having a structure for adjusting the position of the vessel within the press.

1 . A press for removing fluid from a flexible vessel, the press including cooperating press members having an open position to insert the vessel between them, and a closed position to compress the vessel between them, at least one of the press members having a compliant pad on its press surface, the compliant pad compensating for variable thickness of the vessel when it is compressed, and the press being constructed to compress a first portion of the vessel less than a second portion of the vessel.  
   
   
       2 . A press according to  claim 1  wherein the press in the closed position forms a space in a first portion of the press proximate to the first portion of the vessel so that the first portion of the vessel is compressed less than the second portion of the vessel.  
   
   
       3 . A press according to  claim 2  wherein the compliant pad is located on the second portion of the press surface and not on the first portion of the press surface, and defines the space in the first portion of the press.  
   
   
       4 . A press according to  claim 1  wherein the press additionally includes a barrier structure that creates a barrier between the first portion of the vessel and the second portion of the vessel as the vessel is compressed.  
   
   
       5 . A press according to  claim 1  wherein the press additionally includes a barrier structure that creates a barrier between the first portion of the vessel and the second portion of the vessel when the barrier is at least partially under compression.  
   
   
       6 . A press according to  claim 4  wherein the barrier structure seals the vessel between the second and first portions of the vessel.  
   
   
       7 . A press according to  claim 6  wherein the barrier structure comprises a compliant strip that is thicker than the compliant pad.  
   
   
       8 . A press according to  claim 6  wherein the barrier structure comprises a portion of the compliant pad that is stiffer than the remaining portion of the pad.  
   
   
       9 . A press according to  claim 1  wherein the compliant pad comprises a foam pad.  
   
   
       10 . A press according to  claim 7  wherein the compliant strip comprises a foam strip.  
   
   
       11 . A press according to  claim 1  wherein the press in the closed position substantially completely compresses the second portion of the vessel while leaving the first portion of the vessel substantially uncompressed.  
   
   
       12 . A press according to  claim 1  wherein the press members comprise a pair of press plates.  
   
   
       13 . A press according to  claim 12  wherein at least a portion of one or more of the press plates is transparent to allow viewing of the vessel during the pressing operation.  
   
   
       14 . A press according to  claim 12  wherein during the pressing operation the press plates come together first toward the edge of the vessel farthest from the second portion and come together last at an edge farthest from the first portion of the vessel.  
   
   
       15 . A press according to  claim 1  further comprising two barrier structures that each create a barrier line, and wherein the compliant pad defines a substantially uncompressed portion between the barrier lines, and at least one substantially compressed portion outside the portion between the barrier lines, when the press is in a closed position.  
   
   
       16 . A press according to  claim 12  wherein the press additionally includes a base, and wherein one of the press plates is mounted in stationary position on the base and the other of the press plates is pivotally mounted on the base.  
   
   
       17 . A press according to  claim 4  wherein the press additionally includes a mechanism for adjusting the location of at least one of the vessel, the barrier structure, and the compliant pad.  
   
   
       18 . A press for removing supernatant from a flexible vessel, the press including cooperating press members having an open position to insert the vessel between them, and a closed position to compress the vessel between them, at least one of the press members having a compliant pad on its press surface, the compliant pad compensating for variable thickness of the vessel when it is compressed, the press being constructed to compress a first portion of the vessel less than a second portion of the vessel, and the press including a barrier structure that creates a barrier between the first and second portions of the vessel when the vessel is compressed.  
   
   
       19 . A press for removing supernatant from a flexible vessel, the press including: 
 cooperating press members having an open position to insert the vessel between them, and a closed position to compress the vessel between them, at least one of the press members having a compliant pad on its press surface, the compliant pad compensating for variable thickness of the vessel when it is compressed, and the press being constructed to compress a first portion of the vessel less than a second portion of the vessel; and    a vessel holder having a structure for adjusting the height of the vessel within the press.    
   
   
       20 . A press according to  claim 19  wherein the vessel holder comprises a vertically adjustable hanger.  
   
   
       21 . A method of removing a portion of biological material from a flexible process vessel comprising the steps of: 
 (1) providing a flexible process vessel containing fluid biological material at least partially separated by density;    (2) placing the vessel into a press for removing the material of a selected density gradient from the vessel, the press including cooperating press members having an open position to insert the vessel between them, and a closed position to compress the vessel between them, the press being constructed to compress a first portion of the vessel less than a second portion of the vessel; and    (3) pressing the vessel to remove the material of a selected density gradient from the vessel while retaining the remaining biological material in the vessel.    
   
   
       22 . The method of  claim 21   wherein at least one of the cooperating press members further includes a compliant pad on its press surface constructed to compress the first portion of the vessel less than the second portion, and at least one of the cooperating press members further includes a barrier structure constructed to define a barrier between the first and second portions of the vessel; and    wherein the method further includes the steps of adjusting the position of at least one of the vessel, the compliant pad and the barrier structure prior to the step of pressing to define the first and second portions.    
   
   
       23 . The method of  claim 21  wherein at least one of the cooperating press members further includes at least one compliant pad on its press surface constructed to compress a first portion of the vessel less than second and third portions of the vessel, and wherein at least two barrier structures are disposed on the cooperating press members to define the first portion of the vessel between the second and third portions of the vessel; 
 wherein the method further includes the step of pressing the vessel to remove the material of a selected density gradient from the second and third portions of the vessel while retaining the remaining biological material in the first portion of the vessel.    
   
   
       24 . A press according to  claim 21  wherein at least a portion of one or more of the press plates is transparent, and the step of pressing includes the step of monitoring the vessel through a transparent portion of a press plate during the pressing operation.