Mixer

A mixing head comprising:

• a stator body;
• a rotor mounted for rotation within the stator body;
• the stator body including a base section, a mid section and an end section and means for releasably securing the sections together, the mid section being configured to be receivable in mating relationship with the base section and the end section being configured to be received in mating relationship with both the base section and the mid section;
• and
• the rotor including a first head and a second head removably positionable adjacent the first head.

A mixing head comprising:

• a stator having first and second shearing surfaces;
• a shaft mounted for rotation within the stator;
• a first rotor head having a shearing surface on one face thereof;
• means for mounting the first rotor head on the shaft with the shearing surface thereof in operative association with the first shearing surface of the stator;
• a second rotor head positioned downstream from said first rotor head and having a shearing surface on one face thereof;
• means for mounting the second rotor head on the shaft with the shearing surface thereof in operative association with the second shearing surface of the stator;
• the stator and first and second rotor heads defining therebetween a conical fluid flow path including means through which fluid is capable of flowing from said first rotor head to the shearing surface of said second rotor head;
• and
• the stator including means for defining a fluid inlet to the fluid flow path and means for defining a outlet from the fluid flow path.

A process for introducing gas into a liquid comprising:

• (A) directing a flow of a mixture of liquid and gas from an outer annulus inwardly through a substantially planar shearing zone to a concentric inner annulus;
• (B) subjecting said mixture to shearing forces within said shearing zone to effect a foaming of the liquid;
• (C) directing the foam thus formed along a frustoconical flow path which communicates at its smaller end with said inner annulus, the axis of said conical flow path being perpendicular to the plane of said shearing zone;
• (D) subjecting said foam flowing from said frustoconical flow path to additional shearing forces to effect a further foaming of said liquid.

A process for introducing gas into a liquid comprising:

• (A) directing a flow of a mixture of liquid and gas from an outer annulus inwardly through a substantially planar shearing zone to a concentric inner annulus;
• (B) subjecting said mixture to shearing forces within said shearing zone to effect a foaming of the liquid;
• (C) directing the flow of the foam thus formed to a second outer annulus and from said second outer annulus inwardly through a second substantially planar shearing zone to a second concentric inner annulus;
• (D) and subjecting said foam to additional shearing forces within said second shearing zone to effect a further foaming of said liquid.

A process for introducing gas into a liquid comprising:

• (A) directing a flow of a mixture of liquid and gas from an outer annulus inwardly through a substantially planar shearing zone to a concentric inner annulus;
• (B) subjecting said mixture to shearing forces within said shearing zone to effect a foaming of the liquid;
• (C) directing the flow of the foam thus formed to another shearing zone while maintaining on the liquid/gas mixture a back pressure which is effective in maintaining said mixture in its foamed state;
• and thereafter
• (D) subjecting said foam to additional shearing forces within said other shearing zone to effect a further foaming of said liquid.

A device for introducing gas into a liquid comprising:

• (A) first shearing means for foaming said liquid and including a first rotor having periphery and an axis of rotation;
• (B) second shearing means for further foaming said liquid and positioned downstream of said first shearing means and including a second rotor having a periphery and an axis of rotation;
• and
• (C) means defining a flow path between the periphery of said first rotor and the axis of rotation of said second rotor and extending from the periphery of said first rotor to the axis of rotation of said first rotor, from the axis of rotation of said first rotor to the periphery of said second rotor, and from the periphery of said second rotor to the axis of rotation of said second rotor.

A device for introducing gas into a liquid comprising:

• (A) first shearing means for foaming said liquid;
• (B) second shearing means for further foaming said liquid and positioned downstream of said first shearing means;
• wherein each of said first and second shearing means has a common axis of rotation;
• and
• (C) means defining a flow path between said first and second shearing means for transfer of said foam from said first to said second shearing means and disposed at an acute angle with respect to said common axis of rotation.