Cap for an NMR sample tube with inner sealing lip

Abstract

A cap ( 1; 51 ) for an NMR sample tube ( 52 ) having an inner bore ( 3 ) for receiving an open end ( 54 ) of an NMR sample tube ( 52 ), wherein the inner bore ( 3 ) has a narrowing for sealing a received NMR sample tube ( 52 ) against the cap ( 1; 51 ) along the outer periphery of the NMR sample tube ( 52 ), is characterized in that the narrowing is designed as an inner sealing lip ( 4 ). The cap provides good sealing between the cap and the NMR tube, and the cap can be produced from a plurality of materials, in particular, materials with good chemical resistance to NMR solvents.

We claim: 
     
         1 . A cap for an NMR sample tube, the cap comprising:
 means for defining an inner bore to receive an open end of the NMR sample tube; and   an inner sealing lip disposed within said bore to define a narrowing for sealing a received NMR sample tube with respect to the cap along an outer periphery of the NMR sample tube.   
     
     
         2 . The cap of  claim 1 , wherein, in a relaxed state, said sealing lip has a rounded cross-section on a radially inwardly facing side thereof. 
     
     
         3 . The cap of  claim 1 , wherein, in a relaxed state, said sealing lip has a tapering cross-section on a radially inwardly facing side thereof. 
     
     
         4 . The cap of  claim 1 , wherein, in a relaxed state, said cap has a uniform, constant wall thickness in an area of said sealing lip and in surroundings of said sealing lip. 
     
     
         5 . The cap of  claim 1 , wherein said inner bore has a contact ring for holding the NMR sample tube at an outer periphery thereof, wherein said contact ring differs from said sealing lip. 
     
     
         6 . The cap of  claim 5 , wherein said contact ring is disposed closer to an insertion opening for the NMR sample tube than said sealing lip. 
     
     
         7 . The cap of  claim 5 , wherein said contact ring is formed by several separate segments. 
     
     
         8 . The cap of  claim 5 , wherein said contact ring is formed as a further inner sealing lip. 
     
     
         9 . The cap of  claim 1 , wherein the cap has a groove on an outer periphery thereof for engagement of a sample gripper. 
     
     
         10 . The cap of  claim 9 , wherein said groove is designed such that at least three gripping fingers of the sample gripper can engage said groove, such that the gripping fingers can exert pressure on two outer edges of said groove. 
     
     
         11 . The cap of  claim 1 , wherein said inner bore is substantially circular cylindrical or the cap is substantially rotationally symmetrical. 
     
     
         12 . The cap of  claim 1 , wherein the cap has an access channel to said inner bore, which opens into said inner bore in an upper area beyond said sealing lip facing away from an insertion opening for the NMR sample tube. 
     
     
         13 . The cap of  claim 1 , wherein the cap completely closes said inner bore in an upper area beyond said sealing lip facing away from an insertion opening for the NMR sample tube. 
     
     
         14 . The cap of  claim 1 , wherein the cap is produced from plastic material. 
     
     
         15 . An NMR sample configuration comprising a cap and an NMR sample tube onto which the cap can be disposed, wherein the cap is designed in accordance with  claim 1 .