초록 ▼

The relative density of a sample of a supply gas under test is determined by measuring an atmospheric pressure and a pressure differential for the reference gas and the sample gas as each is passed through a small orifice (16) with smooth walls, such as a pore formed in a sapphire jewel. The pressur

The relative density of a sample of a supply gas under test is determined by measuring an atmospheric pressure and a pressure differential for the reference gas and the sample gas as each is passed through a small orifice (16) with smooth walls, such as a pore formed in a sapphire jewel. The pressure measurements are made on a time base determined during the reference gas cycle. A microcontroller (15) then computes a relative density for the sample gas based on a known relative density for the reference gas and a ratio of pressure factors for the sample gas and the reference gas in a system operating at in a range from about 1 to about 6 psig.

대표청구항 ▼

[ We claim:] [1.] A method for measuring the relative density of a gas, the method comprising:flowing a reference gas and a sample gas from a volume chamber through an orifice that is sized to be small relative to a connecting line and sized with respect to an initial pressure of the reference gas a

[ We claim:] [1.] A method for measuring the relative density of a gas, the method comprising:flowing a reference gas and a sample gas from a volume chamber through an orifice that is sized to be small relative to a connecting line and sized with respect to an initial pressure of the reference gas and the sample gas, respectively, such that the effects of a discharge coefficient of the orifice are not necessary to a computation of relative density;measuring an elapsed time of discharge when the reference gas reaches a target discharge pressure;measuring the pressure of the sample gas across the orifice at the elapsed time of discharge determined for the reference gas; andcomputing the relative density of a sample gas from a known relative density of a reference gas, from predetermined constants for the reference gas and the sample gas, respectively, and from a ratio of the pressure of the sample gas across the orifice to the pressure of the reference gas across the orifice.