Ekiryuchunobutsushitsuno choseinodooerusochino kairyo

摘要

1478164 Dissolving gas in liquid flow to controlled concentration GEORGE KENT Ltd 20 Nov 1975 [22 Nov 1974] 50789/74 Heading B1C In a method of and apparatus for dissolving a gas in a flow of liquid to provide a solution of predetermined concentration the flow is divided, in proportions which are independent of the quantity of the total flow, between first and second flow paths and the substance dissolved in the flow in one of those paths to provide a saturated solution which is then recombined with the other flow. In apparatus for providing a controlled concentration of oxygen in a flow of water the total flow passes through an annular space 99 between sleeves 5, 7 before being divided (by valve 117, Fig. 6 not shown) in proportions of about 600:1 the minor flow passing in laminar manner over an elongate coiled tube 137 of oxygen-permeable material and through capillary tube 65 before combining with the main branch flow. The latter passes through a variable orifice device provided by glass ball 93 in an upwardly widening passage 83, the purpose of which is to ensure a linear relation between the flow rate and pressure drop of the main branch flow (which is turbulent) and thus to ensure that the proportions in which the total flow is divided remain constant despite changing flow rate. The ends 139 of the tubing 137 are either open to atmosphere or connected at one end to an aspirator to ensure flow of air therethrough, the length of tubing 137 being adequate to ensure saturation of the minor branch flow with oxygen. The decrease in solubility of oxygen in water with temperature increase would tend to make the apparatus inaccurate with temperature variations but this is largely counterbalanced for the range of 10‹C-40‹C by the different effects on the turbulent and laminar branch flows of temperature-linked changes in viscosity of water. The apparatus may be used for calibrating meters for monitoring dissolved oxygen levels.