Abstract: Devices relating to a psychrometer employing an infrared thermocouple aimed at a wet surface, and another infrared thermocouple aimed at a dry surface, are described. The wet surface is continuously supplied with liquid, for example, H.sub.2 O. The infrared thermocouple which is aimed at the wet surface detects evaporative heat loss instantaneously at the wet surface as it occurs, without coming into contact with the wet surface.

Abstract: The mixing valve includes structure having two gas inlets and two gas outlets. The proportions of the two gases, at each of the outlets, is varied inversely in accordance with the position of a rotatable portion of the mixing valve. If the back pressure at the two outlets is equal, and if the supply pressure of the two gases is equal, the proportioning of the two gases will be accurately determined by the adjustment of the valve. Thus, in an automatically controlled system requiring the presence of gases in time-variable proportions, proper proportioning can be achieved by the use of the mixing valve without the necessity of a gas testing analyzer and a feedback system for controlling a conventional mixture proportioning valve.

Abstract: Method of measuring the oxygen association state of blood samples, which includes the steps of disposing a blood sample within a blood-receiving receptacle, providing a controlled atmosphere chamber, incubating the sample by placing it in the chamber and controlling said atmosphere therein so as to maintain the humidity, temperature, and carbon dioxide content of the atmosphere at substantially constant levels, and thereafter analyzing the sample by changing the concentration of oxygen in said chamber from time to time while observing the changes of oxygen association of the sample with respect to the concentration of oxygen within the chamber.An apparatus which includes two sample holders receiving slides adapted to position the samples in the chamber in incubating and analyzing position, respectively.

Abstract: Two gases are fed to a mixing valve having two outlets, and the proportions of the two gases, at each of the said outlets, is varied inversely in accordance with the position of a moveable portion of the mixing valve. If the back pressure at the two outlets is equal, and if the supply pressure of the two gases is equal, the proportioning of the two gases will be accurately determined by the adjustment of the valve. Thus, in an automatically controlled system requiring the presence of gases in time-variable proportions, proper proportioning can be achieved by the use of a mechanical valve, without the necessity of a gas testing analyzer and a feedback system for controlling an ordinary mixture proportioning valve.

Abstract: A method and apparatus for deriving an oxygen association .[.rate.]. curve for a blood sample wherein the sample is introduced into a transparent-walled cell and is deoxygenated by contact with a deoxygenated fluorocarbon material. The cell is located in the optical path of two time-shared respective monochromatic beams, one having a wavelength at which there is substantially no change in absorbance as between oxygenated and deoxygenated blood and the other having a wavelength at which there is a relatively large change in absorbance as between oxygenated and deoxygenated blood. The difference in absorbance through the cell of the two wavelengths is measured and recorded while oxygenated fluorocarbon titrant material is pumped through the cell, the cell having a restricted flow passage for the titrant material which acts to separate the blood therefrom and retain it in the cell while the titration is taking place.