Patent ID: 9335242
Filing Date: 2016-05-10
CPC Classification: G01N

Claim Text:
1. A method for determining characteristics of a fluid, such as jet fuel, at sub-ambient temperatures, said characteristics including a lower pumpability limit of said fluid, the method including the following steps: connecting an oscillating piston type viscometer to a chiller so that said chiller can rapidly cool said viscometer; placing a sample of said fluid in said viscometer; rapidly cooling said viscometer and said sample with said chiller while measuring temperature and viscosity of said sample; storing said temperatures and viscosities of said sample as measured; analyzing said temperatures and viscosities as measured to first calculate an approximate temperature/viscosity curve of said sample; predicting a pumpability limit of said sample by extrapolation of said approximate temperature/viscosity curve; continue cooling said viscometer and said sample therein; first determining a measured pumpability limit of said sample by measuring the temperature of said sample whereby the maximum allowable viscosity is reached; said chiller further continues to cool said viscometer and said sample therein while further measuring said temperatures and viscosities and further storing said temperatures and viscosities as measured; second calculating the difference between (a) said approximate temperature/viscosity curve of said sample and (b) said measured viscosity; third calculating a second derivative from the difference between (a) said approximate temperature/viscosity curve of said sample and (b) said measured temperature; and second determining temperature T