Patent ID: 6038919
Filing Date: 2000-03-21
Classification: G01F

Abstract:
In a process which includes delivering a processing substance from a storage vessel to a processing station, said storage vessel enclosing a processing substance storage space and being coupled to conduits which communicate with said storage space, the improvement comprising a method for determining the quantity of processing substance in said storage space, which method comprises:determining the volume occupied by a gas within a measurement volume which includes said storage space, including:performing first and second pressure measurement for measuring the gas pressure in said measurement volume when said measurement volume contains respectively first and second quantities of gas; anddetermining the difference between said first and second quantities of gas;wherein said gas volume determining is calculated as follows: ##EQU2## where V.sub.g is said gas volume;k is a constant;T.sub.k is the absolute temperature of said storage vessel in .degree.K.; andP.sub.2 and P.sub.1 are said first and second pressure measurements at ending time t.sub.2 and starting time t.sub.1, respectively.