Patent ID: 8437976

Claim:
A gas density transducer comprising: a pressure sensor providing an output indicative of a pressure applied by a sample gas; a temperature sensor providing an output indicative of a temperature of the sample gas; and a microprocessor having an output, a first input coupled to the output of the pressure sensor, and a second input coupled to the output of the temperature sensor, the microprocessor providing an output indicative of the density of the sample gas, the microprocessor configured to determine a value for z in the equation (p+a*z 2 )(1−b*z)=zRT, wherein z=n/v and 1) provide new variables z 1 and z 2 , and define z 1 =0 and z 2 =1/b; 2) assign new variable z n , wherein z n =(z 1 +z 2 )/2; 3) substitute z n for z in (p+a*z 2 )(1-b*z)=zRT, and calculate value of F in F=(p+a*z n 2 )(1−b*z n )−z n RT; 4) assign new values for z 1 or z 2 , wherein a new value for z 1 is z n defined in step 2 if the value of F calculated in step 3 is greater than zero, and a new value for z 2 is z n defined in step 2 if the value of F calculated in step 3 is less than zero; 5) repeat steps 2-4 if the absolute value of the difference between z 1 and z 2 is greater than 1/b*½ x , wherein x is a predetermined number of bits of resolution; and 6) output z n calculated in step 3 as the approximate value of n/V if the absolute value of the difference between z 1 and z 2 is less than 1/b*½ x .