Centrifugal liquid pump with internal gas injection assembly

Claim 1

In a centrifugal pump for use to pump a liquid, said pump comprising: a) a casing defining an inner, substantially cylindrical chamber, said chamber having a pair of opposite end walls coaxial with each other; b) a liquid inlet in open communication with the chamber, said inlet being coaxial with said chamber and opening into one of the opposite end walls thereof; c) a liquid outlet in open communication with the chamber, said outlet extending tangentially out of said chamber; d) a rotary impeller rotatably mounted within the chamber, said impeller comprising a pair of spaced apart discs of a given radius coaxial with said chamber, said discs being rigidly interconnected at such a distance away from each other as to extend close to said opposite end walls, respectively, one of said discs located adjacent the one opposite end wall into which said liquid inlet opens having a central opening to allow the liquid injected through said inlet to enter the chamber; and e) a power shaft coaxial with and rigidly connected to the other one of said discs so as to rotate the impeller in a given direction within the chamber, said power shaft extending out of said casing in a direction opposite to said liquid inlet; the improvement consisting in a gas-injection assembly for use to inject and dissolve, at least in part, a gas into the liquid while said liquid is being pumped, said assembly comprising: f) a gas feed pipe coaxial with and rigidly connected to the impeller so as to rotate therewith, said gas feed pipe extending coaxially through both the liquid inlet and the opening of the one disc of the impeller in a direction opposite to the power shaft and having a gas inlet located outside said casing and connected through a rotary seal joint to a pressurized gas source, and a gas outlet located within the casing; and g) at least one gas injector pipe rigidly connected to the gas feed pipe so as to rotate in unison therewith and with the impeller to which said gas feed pipe is connected, said at least one injector pipe being perpendicular to said feed pipe and extending radially within said casing between the discs of the impeller, said at least one injector pipe having one end in open communication with the gas outlet of the feed pipe and another radially, opposite end defining a gas nozzle opening within the casing between the discs at a radial distance away from said feed pipe that is shorter than the radius of said discs.

Claim 15

A method for injecting and dissolving a gas into a liquid while said liquid is being pumped, comprising the steps of: a) feeding the liquid to be pumped into a centrifugal pump comprising an impeller consisting of two coaxial discs of given radius having facing surfaces which are spaced apart and from which ribs project at such a distance as to leave a gap therebetween and at the same time b) feeding under pressure the gas to be injected and dissolved through at least two symmetrically positioned gas injector pipes extending radially in the gap left between the discs at a radial distance that is shorter than the radius of said discs, said pipes being rigidly connected to the impeller so as to rotate in unison therewith.

Claim 16

A method for injecting and dissolving a gas into a liquid while said liquid is being pumped, comprising the steps of: a) feeding the liquid to be pumped into a centrifugal pump comprising an impeller consisting of two coaxial discs of given radius having facing surfaces which are spaced apart and from which ribs project at such a distance as to leave a gap therebetween and at the same time b) feeding under pressure the gas to be injected and dissolved through at least two symmetrically positioned gas injector pipes extending radially in the gap left between the discs at a radial distance that is shorter than the radius of said discs, said pipes being rigidly connected to the impeller so as to rotate in unison therewith.