Chromatography pump

Abstract

The invention relates to a chromatography pump, comprising a cylinder ( 202, 402 ) in which a piston ( 204, 404 ) is arranged for a reciprocating movement; a front element ( 208 ) provided with a cylinder head area ( 210 ) which together with the cylinder ( 202, 402 ) and the piston ( 204, 404 ) defines a cylinder space ( 212 ); an inlet valve ( 214 ) and an outlet valve ( 216 ) arranged in the front element ( 208 ); an inlet channel ( 218 ) arranged in the front element ( 208 ) between the inlet valve ( 214 ) and the cylinder head area ( 210 ); an outlet channel ( 220 ) arranged in the front element ( 208 ) between the cylinder head area ( 210 ) and the outlet valve ( 216 ). The inlet channel ( 218 ) and outlet channel ( 220 ) extend in a substantially straight direction, so that air bubbles ( 234 ) are prevented from being trapped within the inlet and outlet channels ( 218, 220 ).

1 . A chromatography pump, comprising a cylinder ( 202 ,  402 ) in which a piston ( 204 ,  404 ) is arranged for a reciprocating movement along an axis ( 248 ); a front element ( 208 ) provided with a cylinder head area ( 210 ) which together with the cylinder ( 202 ,  402 ) and the piston ( 204 ,  404 ) defines a cylinder space ( 212 ); an inlet valve ( 214 ) and an outlet valve ( 216 ) arranged in the front element ( 208 ); an inlet channel ( 218 ) arranged in the front element ( 208 ) between the inlet valve ( 214 ) and the cylinder head area ( 210 ); an outlet channel ( 220 ) arranged in the front element ( 208 ) between the cylinder head area ( 210 ) and the outlet valve ( 216 ), wherein the inlet channel ( 218 ) and outlet channel ( 220 ) extend in a substantially straight direction, and in that the inlet channel ( 218 ) and outlet channel ( 220 ) each extend obliquely to the axis ( 248 ). 
     
     
         2 . The pump of  claim 1 , wherein a cavity ( 242 ) is arranged adjacent the cylinder space ( 212 )and in that an inlet ( 244 ) of the outlet channel ( 220 ) is arranged in the cavity ( 242 ). 
     
     
         3 . The pump of  claim 2 , wherein an outlet ( 240 ) of the inlet channel ( 218 ) is arranged in the cavity ( 242 ). 
     
     
         4 . The pump of  claim 2 , wherein the cavity ( 242 ) has a form substantially corresponding to an arch, so that air bubbles ( 234 ) are prevented from being trapped within the cavity ( 242 ). 
     
     
         5 . The pump of  claim 1 , wherein the front element ( 208 ) is made of PEEK material, titanium or hastelloy. 
     
     
         6 . The pump of  claim 1 , wherein the surface roughness (Ra) of the walls ( 236 ) of the inlet and outlet channels ( 218 ,  220 ) is between 0.2-2.0, preferably between 1.0-2.0. 
     
     
         7 . The pump of  claim 1 , wherein the surface roughness (Ra) of the wall ( 238 ) of the cylinder head area ( 210 ) is between 0.2-2.0, preferably between 1.0-2.0. 
     
     
         8 . The pump of  claim 1 , wherein the inlet and outlet valves ( 214 ,  216 ) are check valves provided with seated balls ( 226 ) in which a weight ( 303 ) arranged on the ball ( 226 ) urges the ball ( 226 ) against the seat ( 228 ). 
     
     
         9 . The pump of  claim 1 , wherein the cylinder head area ( 210 ) has a normal ( 246 ) which substantially coincides with the axis ( 248 ) of the piston ( 204 ). 
     
     
         10 . The pump of  claim 1 , wherein the chromatography pump ( 201 ,  301 ,  401 ) is designed for pumping liquid ( 222 ). 
     
     
         11 . The pump of  claim 1 , wherein a circumferential seal ( 405 ) is arranged on the piston ( 404 ), and a circumferential leaf spring ( 407 ) is arranged to apply an outwardly directed radial load on the seal ( 405 ). 
     
     
         12 . The pump of  claim 11 , wherein a tap ( 409 ) is arranged on an end part ( 411 ) of the piston ( 404 ), which tap ( 409 ) is attached to the piston ( 404 ) and fixates the seal ( 405 ) on the end part ( 411 ) of the piston ( 404 ). 
     
     
         13 . The pump of  claim 1 , wherein the outlet channel ( 220 ) and the inlet and outlet valves ( 214 ,  216 ) extend in a substantially coincident direction, so that the pump may be mounted with outlet channel ( 220 ) in a substantially vertical direction in relation to a horizontal plane ( 308 ).