Patent ID: 6681616
Filing Date: 2004-01-27
Classification: B01L,G01N,G05D,Y10T

Abstract:
A method for determining a difference in viscosity between a sample fluid and a reference fluid, the method comprising the following steps in the order named:flowing a reference fluid with a known viscosity through a first channel segment by applying a first driving force; flowing a detectable fluid through a second channel segment by applying a second driving force; combining the flow of the reference fluid from the first channel segment with the flow of detectable fluid from the second channel segment at a first intersection to produce a first combined flow, the first combined flow entering a third channel segment; measuring a first amount of detectable fluid flowing in the first combined flow; replacing the flow of reference fluid in the first channel segment with a flow of sample fluid through the first channel segment without changing the magnitudes of the first and second driving forces; combining the flow of the sample fluid from the first channel segment with the flow of detectable fluid from the second channel segment at a first intersection to produce a second combined flow, the second combined flow entering a third channel segment; measuring a second amount of detectable fluid flowing in the second combined flow; and determining a difference in viscosity between the reference fluid and the sample fluid from the difference between the first amount of detectable fluid and the second amount of detectable fluid.