Pipetter, pipette tube, sample analyzing apparatus including them and method of mixing and pipetting liquids

A particle analyzer for analyzing suspended particles in a liquid sample, comprising

• (a) at least one sample container for said sample,
• (b) at least one container for a second liquid to be mixed with said sample prior to analysis thereof,
• (c) a sensor for analyzing particles in said sample after mixing with said second liquid,
• (d) a pipetter adapted and arranged for sucking a predetermined quantity of said sample from said sample container, mixing said sample with said second liquid to form a mixture thereof and discharging at least part of said mixture to said sensor, said pipetter comprising
• (i) a pipetting tube having a first end for suction and discharge of liquid being pipetted and a second end,
• (ii) actuating means connected to said second end of said tube for sucking liquid into and discharging liquid from said tube via said first end,
• (iii) flow disturbance means in said tube spaced from said first end and adapted to cause longitudinal mixing of liquid in said tube when liquid is moved past it in at least one direction, and
• (e) control means for said actuating means adapted and arranged to effect the formation of said mixture by causing said actuating means to move a liquid body constituted by said sample and said second liquid repeatedly to and fro along said tube so that during each such movement at least a portion of said liquid body passes said flow disturbance means and said liquid body is not discharged from said first end of said tube.

Sample analyzing apparatus capable of simultaneous handling of a plurality of samples, comprising,

• (a) a plurality of sample containers for said samples,
• (b) at least one sensor for said samples,
• (c) a plurality of pipetters adapted and arranged for sucking said samples from said sample containers, forming mixtures of said samples with a second liquid and discharging said mixtures to said at least one sensor, each said pipetter comprising
• (i) a pipetting tube having a first end for suction and discharge of liquid being pipetted and a second end,
• (ii) flow disturbance means in said tube spaced from said first end and adapted to cause longitudinal mixing of liquid in said tube when liquid is moved past it in at least one direction, and
• (d) actuating means connectable to said second end of said pipetting tubes of said pipetters for sucking liquid into and discharging liquid from said tubes via said first ends thereof, and
• (e) control means for said actuating means adapted and arranged to achieve formation of each said mixture by causing said actuating means to move a liquid body constituted by the respective sample and said second liquid repeatedly to and fro along said tube of the pipetter so that during each such movement at least a portion of said liquid body passes said flow disturbance means while said liquid body is not discharged from said first end of the tube.