Method for pumping fluid in a fluid separation device and related devices and systems

Abstract

In a fluid separation device, fluid supplied to a fluid inlet conduit at an inlet flow rate is split such that a first part of the fluid flows into a first outlet conduit and into a pump at a first flow rate, and a second part of the fluid flows from the fluid inlet conduit into a second outlet conduit at a second flow rate. The second flow rate is controlled by controlling the pump such that, regardless of inlet pressure in the fluid inlet conduit, the first part of the fluid is continuously conducted away from the fluid inlet conduit at a defined value of the first flow rate. The second flow rate is defined based on the defined value of the first flow rate.

What is claimed is: 
     
         1 . A method for pumping a fluid in a fluid separation device for separating the fluid, the method comprising:
 supplying the fluid to a fluid inlet conduit at an inlet flow rate;   splitting the fluid supplied to the fluid inlet conduit such that a first part of the fluid flows from the fluid inlet conduit into a first outlet conduit and into a pump inlet of a pump at a first flow rate, and a second part of the fluid flows from the fluid inlet conduit into a second outlet conduit at a second flow rate; and   controlling the second flow rate of the second part of the fluid, by controlling the pump such that, regardless of a value of an inlet pressure in the fluid inlet conduit, the first part of the fluid is continuously conducted away from the fluid inlet conduit at a defined value of the first flow rate, wherein the second flow rate is defined based on the defined value of the first flow rate.   
     
     
         2 . The method of  claim 1 , comprising at least one of:
 controlling the pump such that the second flow rate is maintained at a constant value, or according to a predefined profile, over a desired time interval;   controlling the pump such that the second flow rate is maintained at a constant value, or according to a predefined profile, over a desired time interval that is larger than one duty cycle of the pump.   
     
     
         3 . The method of  claim 1 , comprising at least one of:
 controlling the pump such that the second flow rate is reduced relative to the inlet flow rate by the defined value;   controlling the pump such that the second flow rate is in a range between 0.01 ml/min and 1 ml/min.   
     
     
         4 . The method of  claim 1 , wherein supplying the fluid to the fluid inlet conduit comprises outputting the fluid from a separation unit configured for separating the fluid. 
     
     
         5 . The method of  claim 4 , comprising detecting the separated fluid in the first outlet conduit upstream of the pump inlet. 
     
     
         6 . The method of  claim 1 , wherein controlling the pump comprises adjusting the pump based on the inlet pressure to maintain the first flow rate at the defined value. 
     
     
         7 . The method of  claim 1 , wherein the pump comprises a first chamber communicating with the pump inlet, a second chamber communicating with the pump inlet, a first piston, and a second piston, and controlling the pump comprises controlling reciprocation of the first piston in the first chamber and reciprocation of the second piston in the second chamber. 
     
     
         8 . The method of  claim 7 , wherein controlling the pump comprises at least one of:
 selectively connecting and disconnecting the first chamber and the second chamber from the pump inlet;   selectively connecting and disconnecting the first chamber and the second chamber from a pump outlet of the pump.   
     
     
         9 . The method of  claim 7 , wherein controlling the pump comprises switching a fluidic valve of the pump to perform at least one of:
 selectively connecting and disconnecting the first chamber and the second chamber from the pump inlet;   selectively connecting and disconnecting the first chamber and the second chamber from a pump outlet of the pump.   
     
     
         10 . The method of  claim 7 , wherein controlling the pump comprises controlling the reciprocation of the first piston and the second piston cooperatively to conduct the first part of the fluid away from the fluid inlet when the first piston is moving rearwardly in the first chamber and when the second piston is moving rearwardly in the second chamber. 
     
     
         11 . The method of  claim 10 , wherein controlling the pump comprises controlling a fluidic valve switchable to selectively connect the first chamber to the first inlet and selectively connect the second chamber to the first inlet. 
     
     
         12 . The method of  claim 11 , wherein controlling the pump comprises controlling the fluidic valve to connect the first chamber to the first inlet when the first piston reverses direction from moving forwardly to moving rearwardly, and to connect the second chamber to the first inlet when the second piston reverses direction from moving forwardly to moving rearwardly. 
     
     
         13 . The method of  claim 10 , wherein controlling the pump comprises controlling the reciprocation of the first piston and the second piston such that the first piston is disconnected from the fluid inlet while the first piston is moving forwardly in the first chamber, and the second piston is disconnected from the fluid inlet while the second piston is moving forwardly in the second chamber. 
     
     
         14 . The method of  claim 13 , wherein controlling the pump comprises controlling a fluidic valve switchable to selectively disconnect the first chamber to from the first inlet and selectively disconnect the second chamber from the first inlet. 
     
     
         15 . The method of  claim 14 , wherein controlling the pump comprises controlling the fluidic valve to disconnect the first chamber from the first inlet when the first piston reverses direction from moving rearwardly to moving forwardly, and to disconnect the second chamber from the first inlet when the second piston reverses direction from moving rearwardly to moving forwardly. 
     
     
         16 . The method of  claim 1 , wherein the pump comprises a plurality of pistons each being controllable for reciprocating forwardly and rearwardly within a respective chamber to thereby conduct fluid away from the fluid inlet with the definable flow rate (FT), wherein the plurality of pistons are controlled so that:
 a sum of displaced fluid volume per time by all presently rearwardly moving pistons being in fluid communication with the fluid inlet,   minus   a sum of displaced fluid volume per time by all presently forwardly moving pistons being in fluid communication with the fluid inlet,   is constant over time.   
     
     
         17 . The method of  claim 1 , comprising conducting the second part of the fluid at the second flow rate toward a fluidic member communicating with the second outlet conduit. 
     
     
         18 . The method of  claim 17 , wherein the fluidic member has a desired flow rate, and controlling the pump comprises controlling the defined value of the first flow rate such that the second flow rate equals the desired flow rate. 
     
     
         19 . The method of  claim 17 , comprising at least one of:
 the fluidic member comprises a mass spectroscopy device and the separation unit comprises a chromatography device;   the fluidic member is selected from the group consisting of: a detector device; a device for chemical, biological and/or pharmaceutical analysis; a capillary electrophoresis device; a liquid chromatography device; an HPLC device; a gas chromatography device; a gel electrophoresis device; a mass spectroscopy device; a another pump; a sensor; and a combination of two or more of the foregoing.   
     
     
         20 . The method of  claim 17 , comprising operating the fluidic member to analyze at least a portion of the second part of the fluid.