Mixing system for dispersing a compressible fluid such as gas into

Abstract

The gas outlet of a pipe or other sparging device is encompassed by a cover or cap which is located between the gas outlet and the mixing impeller at the bottom of a vessel. The cap is closed at the top and has a side wall so that the gas bubbles disperse around the lower rim of the wall. The wall may be non-symmetric, such as square in cross section, so as to be at different radial positions with respect to the gas outlet. The gas bubbles, even if released in pulses are distributed spatially and in time. The lower rim is preferable serrated (as a saw tooth edge) with the teeth being of different height, thereby further spreading the distribution of the bubbles as they are dispersed. The overlap or distance between the rim and the gas outlet is such that a sufficient quantity of gas is confined around the outlet to damp pressure pulsations when the pressure of the gas at the outlet does not significantly exceed the hydrostatic pressure at the outlet into the liquid. It is believed that the cap defines an acoustic filter which damps and effectively reduces pressure pulses. A turning cone below the top of the cover and facing the outlet may be used to facilitate more uniform distribution of the gas bubbles.