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AssigneeWyatt Technology Corporation
InventorSteven Trainoff
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A thermally controlled stage is connected within one arm of a bridge of a capillary bridge viscometer so that the bridge can be balanced in situ to provide accurate measurement signals. The thermally controlled stage includes a tuning capillary tubing portion that is wrapped around a thermally conductive core. A resistance heater or a Peltier thermoelectric device is located in close proximity to the capillary tubing portion. The heater or Peltier device and the capillary tubing portion are located within a thermally insulated housing. The heater or Peltier device varies the temperature of the capillary tubing portion to cause a corresponding change in the flow impedance of the tuning capillary tubing portion of the arm of the bridge in which the thermally controlled stage is connected. The temperature of the tuning capillary tubing portion is monitored and adjusted until any pressure differential across the bridge is eliminated, whereby to trim in the balance of the bridge.
A capillary bridge viscometer having a bridge for receiving a solvent and containing a first pair of series connected fluid tubing arms and a second pair of series connected fluid tubing arms, said second pair of fluid tubing arms connected in parallel with said first pair of series connected fluid tubing arms between fluid supply and fluid discharge ports, and a thermally controlled stage connected into one of said fluid tubing arms by which to balance said bridge, said thermally controlled stage comprising a thermally conductive capillary tubing portion having a flow impedance and means to change the temperature of said capillary tubing portion to correspondingly change the flow impedance thereof until the differential pressure across said bridge is 0.
For a capillary bridge viscometer having a bridge for receiving a solvent and fluid samples to be analyzed and containing a first pair of series connected fluid tubing arms and a second pair of series connected fluid tubing arms, said second pair of fluid tubing arms connected in parallel with said first pair of series connected fluid tubing arms between fluid supply and fluid discharge ports, a method for balancing said bridge including the step of regulating the temperature of at least one fluid tubing arm of said first and second pairs of fluid tubing arms relative to the other fluid tubing arms until the differential pressure across said bridge is 0.
Dependencies are inferred from the claim text.