A concentration measurement system for binary gas mixtures using two flowmeters

Abstract

A system has been constructed for measurement of the gas concentration in a binary gas mixture and of the total flow rate of the gas mixture, using a venturi flowmeter and a laminar flowmeter. The flow rate and air concentration in tested gas mixtures, consisting of air and carbon dioxide or helium, are measured. The results are compared with reference values and the obtained results are found to be similar to those obtained using existing flowmeters and concentration meters. The response of the system to the flow rate and the mixing ratio change is tested. The flow rate change response is approximately equivalent to existing flowmeters, and the concentration change response is better than for existing meters.

A Fast and Easily-Realized Concentration Sensor for Binary Gas Mixtures and Its Design Analysis

“…Zhao et al introduced an extinguishing agent detector for CO 2 ranging from 0 to 100% with an error range within 2% FS, which was achieved by sensing pressure drop caused by viscosity variation, but it experiences trouble when the viscosity is not monotone with concentrations such as CBrF 3 discussed in Section 4 , and when the response time is not researched [ 13 ]. Yamazaki et al described a detection system by sensing pressure drop caused by the change of density and viscosity under the same flowrate, which the response time could reach to 0.2 s, but the accuracy for detection of CO 2 was not good, and the error was within 8.8% FS (range from 0 to 100%) [ 14 ]. Youn et al improved Yamazaki’s device by matching different flowmeters with the errors within ±4% FS, and unlike Yamazaki’s their device was achieved by sensing pressure drop caused by density change or viscosity change, but when the density is similar and viscosity is not monotone, there will be problems [ 15 ].…”

A study on gaseous extinguishing agent sensing with a simple measurement method

“…Zhao et al introduced a low-cost detector for CO 2 that ranged from 0 to 100% (errors within 2% FS) by measuring the change in viscosity, but the response time was not mentioned, and it could only be used for gas mixtures in which the viscosity changed monotonously with concentration [19]. Yamazaki proposed a concentration system that was achieved by sensing the change in density and viscosity under the same flow rate, and its response was very fast, within 0.3 s, while the errors of concentration measurement were within −8.8% to 6.7% FS [20]. Youn et al described a concentration measurement method by sensing the change of viscosity under the same flow rate, which avoided the ill conditions caused by density and viscosity, but the errors were within ±4% FS, and it was not suitable for viscosity, which does not have a monotonic function with gas concentration [21].…”

Improvable method for Halon 1301 concentration measurement based on infrared absorption

“…However, the temporal resolution of this system is not mentioned. Shunpei Yamazaki et al developed a concentration measurement system for binary gas mixtures using a venture flow meter and a laminar flow meter [12]. By measuring the output differential pressure, the concentration of gas can be measured.…”