Methods and apparatus for controlling the supply of a feed gas to

Abstract

The supply of a gas to be dissolved in a liquid is controlled by initially sensing the concentration of dissolved gas in the liquid under treatment and subsequently producing appropriate control signals for adjusting the setting of a valve in the gas supply line. A dissolution device emplaceable in the liquid under treatment includes a liquid inlet and outlet and a static liquid-gas mixing means therebetween. The device is adapted to receive supplied gas whereby a gas space in the upper reaches of the device is established. The gas space is also maintained in communication with a dip tube disposed exteriorly of the device in the body of liquid with the lower extremity of the dip tube establishing the maximum height of the gas space within the dissolution device. The static mixing means comprises a gravitational fall device such that upon detecting an increase or decrease in the concentration of gas dissolved in the body of liquid, the supply of gas to the fall zone is reduced or increases, respectively, thereby decreasing or increasing the rate of gas dissolution. Upon reducing the supply of gas the electrical power necessary to pump liquid through the dissolution device is also conserved. In this manner, the supply of gas is correlated to the demand of the liquid therefor and wastage of electrical power necessary to effect the gas-liquid mixing within the dissolution device is substantially avoided.