Piezo-controlled and-or pressure ripple compensating fluid separation pump

Abstract

An embodiment discloses a fluid pump for use in a fluid separation system for separating compounds of a fluidic sample in a mobile phase, the fluid pump comprising a reciprocatable piston configured for moving the mobile phase, a pump drive configured for driving the reciprocatable piston, and a control unit configured for controlling the pump drive so that pressure ripples in a pressure profile of the fluid pump are at least partially compensated to thereby bring the pressure profile in accordance with a predefined target characteristic. Another embodiment discloses a fluid pump for use in a fluid separation system for separating compounds of a fluidic sample in a mobile phase, the fluid pump comprising a reciprocatable piston configured for moving the mobile phase, and a pump drive configured for driving the reciprocatable piston using a piezomechanism.

1 . A fluid pump for use in a fluid separation system for separating compounds of a fluidic sample in a mobile phase, the fluid pump comprising:
 a reciprocatable piston configured for moving the mobile phase;   a pump drive configured for driving the reciprocatable piston;   wherein the pump drive comprises a base drive unit and a piezo drive unit, the base drive unit being configured for providing a base drive component for driving the piston, and the piezo drive unit being configured for providing an additional drive component for driving the piston.   
     
     
         2 . The fluid pump of  claim 1 , comprising a control unit configured for controlling the pump drive so that pressure ripples in a pressure profile of the fluid pump are at least partially compensated to thereby bring the pressure profile in accordance with a predefined target characteristic. 
     
     
         3 . The fluid pump of  claim 1 , wherein the pump drive comprises a single piezo drive. 
     
     
         4 . The fluid pump of  claim 1 , wherein the pump drive comprises a plurality of piezo drives cooperating for mutually driving the reciprocatable piston. 
     
     
         5 . The fluid pump of  claim 1 , wherein the base drive component has a larger amplitude than the additional drive component. 
     
     
         6 . The fluid pump of  claim 1 , further comprising a control unit configured for controlling the base drive unit and the piezo drive unit for simultaneous operation, thereby simultaneously providing the base drive component and the additional drive component. 
     
     
         7 . The fluid pump of  claim 2 , wherein the control unit is configured for activating the additional drive component upon determining a discrepancy between an actual pressure profile of the fluid pump and a predefined target characteristic of the pressure profile. 
     
     
         8 . The fluid pump of  claim 2 ,
 the base drive unit providing a piston drive contribution continuously; and   the control unit being configured for activating the additional drive component only upon determining a discrepancy between an actual pressure profile of the fluid pump and a predefined target characteristic of the pressure profile.   
     
     
         9 . The fluid pump of  claim 1 , wherein the additional drive component is configured to provide at least one of the group consisting of a fine adjustment of driving the reciprocatable piston, and a correction of driving the reciprocatable piston. 
     
     
         10 . The fluid pump of  claim 1 , wherein the additional drive component is arranged spatially between the reciprocatable piston and the base drive unit. 
     
     
         11 . The fluid pump of  claim 1 , comprising a force transmission body, particularly a force transmission ball, arranged between the reciprocatable piston and the piezo drive unit. 
     
     
         12 . The fluid pump of  claim 1 , wherein the piezo drive unit is arranged to directly act on the reciprocatable piston. 
     
     
         13 . The fluid pump  claim 2 , comprising:
 a sensor configured for sensing an actual pressure profile of the fluid pump;   wherein the control unit is configured for controlling the pump drive so that the actual pressure profile is brought in accordance with the predefined target characteristic.   
     
     
         14 . The fluid pump of  claim 2 , comprising a storage unit accessible by the control unit and storing data being indicative of a compensation scheme for controlling the pump drive so that a characteristic pressure profile of the fluid pump is brought in accordance with the predefined target characteristic. 
     
     
         15 . The fluid pump of  claim 2 , wherein the pressure ripples are ripples of a periodic pattern in the pressure profile of the fluid pump. 
     
     
         16 . The fluid pump of  claim 2 , comprising a fluid inlet valve arranged upstream with respect to a housing of the piston and/or comprising a fluid outlet valve arranged downstream with respect to the housing of the piston, the fluid inlet valve and/or the fluid outlet valve being switchable synchronized with a reciprocation of the piston and causing the pressure ripples. 
     
     
         17 . The fluid pump of  claim 16 , wherein the sensor is arranged upstream or downstream, particularly directly upstream or downstream, the fluid outlet valve. 
     
     
         18 . A fluid separation system for separating compounds of a fluidic sample in a mobile phase, the fluid separation system comprising:
 a fluid pump according to  claim 1  configured to drive the mobile phase through the fluid separation system;   a separation unit, particularly a chromatographic column, adapted for separating compounds of the fluidic sample in the mobile phase.   
     
     
         19 . A method of operating a fluid pump for use in a fluid separation system for separating compounds of a fluidic sample in a mobile phase, the fluid pump having a reciprocatable piston and a pump drive for driving the reciprocatable piston, the pump drive comprising a base drive unit and a piezo drive unit, the method comprising:
 driving the reciprocatable piston using the base drive unit and the piezo drive unit for moving the mobile phase.   
     
     
         20 . A fluid pump for use in a fluid separation system for separating compounds of a fluidic sample in a mobile phase, the fluid pump comprising:
 a reciprocatable piston configured for moving the mobile phase;   a pump drive configured for driving the reciprocatable piston;   wherein the pump drive comprises a base drive unit and a piezo drive unit, the base drive unit being configured for providing a base drive component for driving the piston, and the piezo drive unit being configured for providing an additional drive component for driving the piston;   the fluid pump further comprising a control unit configured for controlling the pump drive so that pressure ripples in a pressure profile of the fluid pump are at least partially compensated to thereby bring the pressure profile in accordance with a predefined target characteristic;   the base drive unit providing a piston drive contribution continuously; and   the control unit being configured for activating the additional drive component only upon determining a discrepancy between an actual pressure profile of the fluid pump and a predefined target characteristic of the pressure profile;   wherein the base drive component has a larger amplitude than the additional drive component.   
     
     
         21 . A fluid pump for use in a fluid separation system for separating compounds of a fluidic sample in a mobile phase, the fluid pump comprising:
 at least one piezo mechanism configured for moving the mobile phase;   a controller configured for driving the at least one piezo mechanism;   wherein the controller is further configured to drive the piezo mechanism to move the mobile phase through a fluidic path in the fluid pump and to suppress pressure ripples in the fluidic path.   
     
     
         22 . The fluid pump of  claim 21  wherein the at least one piezo mechanism comprises a parallel cascade of piezo elements.