China 
Africa 
Explore chapters and articles related to this topic
Laboratory Gas Pipeline Design
Published in James Moody, Design and Construction of Laboratory Gas Pipelines, 2019
Gas sensor types that should be considered include: Oxygen sensor – to measure the oxygen level in the laboratory to ensure that the minimum oxygen level does not fall below 19% or increase above 23% (these values may be subject to international or national Regulations and must be confirmed).Carbon dioxide sensor – to measure the CO2 level to ensure it does not increase above 500 ppm.
*
Published in Neil McManus, Safety and Health in Confined Spaces, 2018
Neil McManus, Robert E. Henderson
Most calibration gas mixtures used to verify the accuracy of the oxygen sensor in a confined space instrument use a concentration that is less than 20.9%. The purpose for this is to activate the appropriate alarms when the sensor is exposed to the gas mixture. This means that if the sensor is working properly, readings should drop to the concentration indicated on the label of the calibration gas cylinder and the low 02 alarm should activate. When calibration gas is not available in the field, ensure that the oxygen sensor reads 20.9% in fresh air, then exhale onto the sensor. Readings should decrease (in many cases to a low enough level to activate the low oxygen alarm), then recover. Readings which fail to decrease, or which require an abnormally long time to recover fully, may indicate a problem with the sensor. Table 10.2 summarizes failure mechanisms in oxygen sensors.
Fiber Optic- and MEM-Based Measurements
Published in Rajpal S. Sirohi, Introduction to OPTICAL METROLOGY, 2017
The oxygen sensor contains an emitter, a light-emitting diode, which emits radiation at two different wavelengths (630 and 960 nm) depending on the polarity of the applied voltage, and a detector, which measures the irradiance (intensity) incident on it. In practice, the emitter and the detector are placed on either side of the bodily appendage, say a finger or an earlobe, and the absorption of the light emitted at each wavelength by the intervening tissue is measured. The oxygen saturation of blood is computed using the relation Oxygen saturation=A−B{D0(λ1)D0(λ2)}
Minreview: Recent advances in the development of gaseous and dissolved oxygen sensors
Published in Instrumentation Science & Technology, 2019
Q. Wang, Jia-Ming Zhang, Shuai Li
The existing dissolved oxygen sensors were varied. They use various devices or instruments to measure the electrical or optical signals generated by oxygen molecules in the chemical, electrochemical, and photochemical reactions and convert the signals uniformly into electrical signals. Following the amplification, processing, and analog-digital conversion, the results are sent to the instrument display interface in order to report the dissolved oxygen concentration. Dissolved oxygen sensor can be divided into three types: chemical, electrochemical, and optical. These devices have their own characteristics that depend on the testing environment. The conditions for each must be optimized.