US 5,179,523 AGranted

Method for determining the mole percent of a gas in binary gas mixture

OwnerWalter A. Johnsoninventor

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Abstract

A method for providing a real time measurement of the purity of one gas in a binary mixture of two known gases applies principles of the fan laws and ideal gas laws in a manner whereby the volume percent purity of the gas may be calculated directly from measured fan differential pressure. The calculated purity is preferably corrected for variations in temperature and pressure. The method requires the determination and use of an appropriate fan constant based on the gas whose purity is to be measured and specific to the fan being used to circulate the gas mixture and the speed at which it operates. An appropriate adjustment factor for differences between design and measured speed may also be applied in accordance with the fan laws. The method can provide real time measurement of hydrogen gas purity in the cooling gas circulated inside a large synchronous AC generator and utilizing a microprocessor to provide a real time output of hydrogen gas purity.

Claims11

Dependent claims

A method for determining the volume percent purity of a first gas in a binary mixture of the first gas and a second known gas, comprising the steps of:

(1) circulating said binary gas mixture in an enclosed system by a fan;
(2) determining a first fan differential pressure with the fan operating at a first speed and with said first gas at 100% purity in the system;
(3) measuring a second fan differential pressure with the fan operating at said first speed and with the gas binary mixture in the system;
(4) calculating a ratio of said first and second fan differential pressures;
(5) using the ratio of said first and second fan differential pressures to calculate the volume percent purity of said first gas in accordance with the equations:
dP.sub.M /DP.sub.1 =W.sub.M /W.sub.1 and, W.sub.M =W.sub.1 (X)+W.sub.2 (1-X),
where:
X=X.sub.c =volume percent purity of said first gas as a decimal fraction
dP.sub.M =measured fan differential pressure with the gas mixture
DP.sub.1 =fan differential pressure with the first gas
W.sub.M =molecular weight of the gas mixture
W.sub.1 =molecular weight of the first gas
W.sub.2 =molecular weight of the second gas;
(6) recalculating a first gas volume percent purity for variations in system pressure and temperature.

11 more elements

Dependencies are inferred from the claim text.