Abstract: A device is disclosed for measuring the concentration of a component of a complex medium, including a dialyzer for separating at least a portion of the component into the dialysate from the complex medium, means for measuring the concentration of the component in the dialyzate, and valve means having a measurement position and calibration position for alternatingly directing the complex medium and a calibration solution, respectively, to the dialyzer so that a calibration of the measuring means can be achieved at intervals between measurements, with the dialyzer being in fluid communication with the measuring means so that the dialyzate from the dialyzer is directed to the measuring means for measuring the concentration of the component in the dialyzate. The device also preferably includes an enzyme reactor.

Abstract: A method and apparatus is provided for measuring the content of a compound in a liquid medium, and which is particularly useful for measuring the concentration of a low molecular weight compound in a complex medium in which there is provided a dialyzer in contact with the complex fluid medium and through which dialysis fluid is conducted to receive by diffusion a portion of the low molecular weight compound to produce a dialysate. The dialysate with the low molecular weight commpound to be examined is first conducted through a venting device for removal of gaseous particles therefrom before conduction through a reaction chamber containing enzymes for promoting the conversion of the low molecular weight compound in the dialysate into a converted reaction product.

Abstract: A flow meter is provided for measuring the flow rate of fluid through a conduit having an inlet and an outlet, which includes a measuring chamber having a float disposed therein for movement in response to fluid flow, and a detector for detecting the movement of the float in the measuring chamber. Various devices are provided for controlling the path of fluid flow from the conduit outlet to the conduit inlet, which includes apparatus for allowing fluid to flow from the outlet through the measuring chamber in a first direction so as to move the float in the first direction past the detector, and for also allowing fluid to flow from the outlet through the measuring chamber in a second direction so as to move the float in the second direction past the detector. Apparatus is connected to the detector for measuring the rate of fluid flow in response to the movement of the float in the first and second directions.