Relating to centrifugal pump impellers

An impeller for use in a centrifugal pump, the pump including a pump casing having a chamber therein, an inlet for delivering material to be pumped to the chamber and an outlet for discharging material from the chamber, the impeller being mounted for rotation within the chamber when in use about a rotation axis, the impeller including a front shroud, a back shroud and a plurality of pumping vanes therebetween, each pumping vane having a leading edge in the region of an impeller inlet and a trailing edge, wherein the front shroud has an arcuate inner face in the region of the impeller inlet, the arcuate inner face having a radius of curvature (Rs) in the range from 0.05 to 0.16 of the outer diameter of the impeller (D2), said back shroud having an inner main face and a nose having a curved profile with a nose apex in the region of the central axis which extends towards the front shroud, there being a curved transition region between the inner main face and the nose, wherein Inr is the radius of curvature of the curved profile of the nose, the ratio Inr/D2 being from 0.17 to 0.22.

An impeller for use in a centrifugal pump, the pump including a pump casing having a chamber therein, an inlet for delivering material to be pumped to the chamber and an outlet for discharging material from the chamber, the impeller being mounted for rotation within the chamber when in use about a rotation axis, the impeller including a front shroud, a back shroud and a plurality of pumping vanes therebetween with passageways between adjacent pumping vanes, each pumping vane having a leading edge in the region of an impeller inlet and a trailing edge, wherein the front shroud has an arcuate inner face in the region of the impeller inlet, the inner face having a radius of curvature (Rs) in the range from 0.05 to 0.16 of the outer diameter of the impeller (D2) and wherein one or more of the passageways have one or more discharge guide vanes associated therewith, the or each discharge guide vane being located at a main face of at least one of the shrouds.

An impeller for use in a centrifugal pump, the pump including a pump casing having a chamber therein, an inlet for delivering material to be pumped to the chamber and an outlet for discharging material from the chamber, the impeller being mounted for rotation within the chamber when in use about a rotation axis, the impeller including a front shroud, a back shroud and a plurality of pumping vanes therebetween, each pumping vane having a leading edge in the region of an impeller inlet and a trailing edge with a main portion therebetween, wherein each pumping vane has a vane leading edge having a radius Rv in the range from 0.18 to 0.19 of the pumping vane thickness Tv of the main portion thereof.

An impeller which includes a front shroud and a back shroud, the back shroud including a back face and an inner main face with an outer peripheral edge and a central axis, a plurality of pumping vanes projecting from the inner main face of the back shroud to the front shroud, the pumping vanes being disposed in spaced apart relation on the inner main face providing a discharge passageway between adjacent pumping vanes, each pumping vane including a leading edge portion in the region of the central axis and a trailing edge portion in the region of the peripheral edge, the back shroud further including a nose having a curved profile with a nose apex in the region of the central axis which extends towards the front shroud, there being a curved transition region between the inner main face and the nose, wherein In is the radius of curvature of the curved profile of the nose and D2 is the diameter of the impeller, the ratio Inr/D2 being from 0.02 to 0.5, wherein one or more of the passageways have associated therewith one or more discharge guide vanes the or each discharge guide vanes being located at a main face of at least one of the shrouds.

An impeller which includes a front shroud and a back shroud, the back shroud including a back face and an inner main face with an outer peripheral edge and a central axis, a plurality of pumping vanes projecting from the inner main face of the back shroud to the front shroud, the pumping vanes being disposed in spaced apart relation on the inner main face providing a discharge passageway between adjacent pumping vanes, each pumping vane including a leading edge portion in the region of the central axis and a trailing edge portion in the region of the peripheral edge, the back shroud further including a nose having a curved profile with a nose apex in the region of the central axis which extends towards the front shroud, there being a curved transition region between the inner main face and the nose, wherein Inose is the distance from a plane containing the inner main face of the back shroud to the nose apex at right angles to the central axis, and B2 is the pumping vane width, and the ratio Inose/B2 being from 0.25 to 0.75, wherein one or more of the passageways have associated therewith one or more discharge guide vanes the or each discharge guide vanes being located at a main face of at least one of the shrouds.

An impeller which includes a front shroud and a back shroud, the back shroud including a back face and an inner main face with an outer peripheral edge and a central axis, a plurality of pumping vanes projecting from the inner main face of the back shroud to the front shroud, the pumping vanes being disposed in spaced apart relation on the inner main face providing a discharge passageway between adjacent pumping vanes, each pumping vane including a leading edge portion in the region of the central axis and a trailing edge portion in the region of the peripheral edge, the back shroud further including a nose having a curved profile with a nose apex in the region of the central axis which extends towards the front shroud, there being a curved transition region between the inner main face and the nose, wherein Fr is the radius of curvature of the transition region and D2 is the diameter of the impeller, and the ratio Fr/D2 being from 0.20 to 0.75, wherein one or more of the passageways have associated therewith one or more discharge guide vanes the or each discharge guide vanes being located at a main face of at least one of the shrouds.

An impeller according to any one of the preceding claims, wherein the pumping vane leading edge angle A1 to the impeller central axis is from 20° to 35°.

An impeller according to any one of the preceding claims, wherein the impeller inlet diameter D1 is in the range from 0.25 to 0.75 of the impeller outer diameter D2.

In combination, an impeller according to any one of the preceding claims and a front liner, the front liner having a raised lip which subtends an angle (A3) to the impeller central axis in the range from 10° to 80°.

In combination, an impeller according to any one of the preceding claims and a front liner, the front liner having an inner end and an outer end, the diameter D4 of the inner end being in the range 0.55 to 1.1 of the diameter D3 of the outer end.

In combination, an impeller according to any one of the preceding claims and a front liner, defining an angle A2 between the parallel faces of the impeller and front liner, and a plane normal to the rotation axis which is in the range from 0° to 20°.

A method of retrofitting an impeller to a centrifugal pump, the pump including a pump casing having a chamber therein, an inlet for delivering material to be pumped to the chamber and an outlet for discharging material from the chamber, the impeller being mounted for rotation within the chamber when in use about a rotation axis the impeller being in accordance with any one of the preceding claims, the method including operatively connecting the impeller to a drive shaft of a drive which extends into the chamber.

An impeller for use in a centrifugal pump, the pump including a pump casing having a chamber therein, an inlet for delivering material to be pumped to the chamber and an outlet for discharging material from the chamber, the impeller being mounted for rotation within the chamber when in use about a rotation axis, the impeller including a front shroud and a back shroud, each having a main inner face in a plane substantially at right angles to the rotation axis and a plurality of pumping vanes therebetween, each pumping vane having a leading edge in the region of an impeller inlet and a trailing edge, wherein the front shroud has an arcuate inner face in the region of the impeller inlet, the arcuate inner face has a profile defined by the following:

• yn=−2.3890009903xn5+19.4786939775xn4−63.2754154980xn3+102.6199259524xn2−83.4315403428x+27.7322233171
• where the yn axis is in the plane of the back shroud main inner face and the xn axis is coaxial with the rotation axis, and yn equals y/(0.5×D2) and xn equals x/B2, wherein x and y define the actual coordinates of an impeller front shroud arcuate inner face, and D2 (which is the impeller outside diameter) is 550 mm, and B2 (which is the impeller outlet width) is 72 mm.

An impeller for use in a centrifugal pump, the pump including a pump casing having a chamber therein, an inlet for delivering material to be pumped to the chamber and an outlet for discharging material from the chamber, the impeller being mounted for rotation within the chamber when in use about a rotation axis, the impeller including a front shroud and a back shroud, each having a main inner face in a plane substantially at right angles to the rotation axis and a plurality of pumping vanes therebetween, each pumping vane having a leading edge in the region of an impeller inlet and a trailing edge, wherein the back shroud further includes a nose having a curved profile with a nose apex in the region of the rotation axis which extends towards the front shroud wherein the curved profile is defined by the following:

• y=−87.6924201323xn5+119.7707929717xn4−62.3921978066xn3+16.0543468684xn2−2.7669594052x+0.5250083657
• where the yn axis is in the plane of the back shroud main inner face and the xn axis is coaxial with the rotation axis, and yn equals y/(0.5×D2) and xn equals x/B2, wherein x and y define the actual coordinates of an impeller back shroud further including a nose having a curved profile, and D2 (which is the impeller outside diameter) is 550 mm, and B2 (which is the impeller outlet width) is 72 mm.

An impeller for use in a centrifugal pump, the pump including a pump casing having a chamber therein, an inlet for delivering material to be pumped to the chamber and an outlet for discharging material from the chamber, the impeller being mounted for rotation within the chamber when in use about a rotation axis, the impeller including a front shroud and a back shroud, each having a main inner face in a plane substantially at right angles to the rotation axis and a plurality of pumping vanes therebetween, each pumping vane having a leading edge in the region of an impeller inlet and a trailing edge, wherein the front shroud has an arcuate inner face in the region of the impeller inlet, the arcuate inner face has a profile defined by the following:

• yn=−7.0660920862xn5+56.8379443295xn4−181.1145997000xn3+285.9370452104xn2−223.9802206897x+70.2463717260
• where the yn axis is in the plane of the back shroud main inner face and the xn axis is coaxial with the rotation axis, and yn equals y/(0.5×D2) and xn equals x/B2, wherein x and y define the actual coordinates of an impeller front shroud arcuate inner face, and D2 (which is the impeller outside diameter) is 1560 mm, and B2 (which is the impeller outlet width) is 190 mm.

An impeller for use in a centrifugal pump, the pump including a pump casing having a chamber therein, an inlet for delivering material to be pumped to the chamber and an outlet for discharging material from the chamber, the impeller being mounted for rotation within the chamber when in use about a rotation axis, the impeller including a front shroud and a back shroud, each having a main inner face in a plane substantially at right angles to the rotation axis and a plurality of pumping vanes therebetween, each pumping vane having a leading edge in the region of an impeller inlet and a trailing edge, wherein the back shroud further includes a nose having a curved profile with a nose apex in the region of the rotation which extends towards the front shroud wherein the curved profile is defined by the following:

• yn=−52.6890959578xn5+79.4531495101xn4−45.7492175031xn3+13.0713205894xn2−2.5389732284x+0.5439201928
• where the yn axis is in the plane of the back shroud main inner face and the xn axis is coaxial with the rotation axis, and yn equals y/(0.5×D2) and xn equals x/B2, wherein x and y define the actual coordinates of an impeller back shroud further including a nose having a curved profile, and D2 (which is the impeller outside diameter) is 1560 mm, and B2 (which is the impeller outlet width) is 190 mm.

An impeller for use in a centrifugal pump, the pump including a pump casing having a chamber therein, an inlet for delivering material to be pumped to the chamber and an outlet for discharging material from the chamber, the impeller being mounted for rotation within the chamber when in use about a rotation axis, the impeller including a front shroud and a back shroud, each having a main inner face in a plane substantially at right angles to the rotation axis and a plurality of pumping vanes therebetween, each pumping vane having a leading edge in the region of an impeller inlet and a trailing edge, wherein the front shroud has an arcuate inner face in the region of the impeller inlet, the arcuate inner face has a profile defined by the following:

• yn=−0.8710521204xn5+7.8018806610xn4−27.9106218350xn3+50.0122747105xn2−45.1312740213x+16.9014790579
• where the yn axis is in the plane of the back shroud main inner face and the xn axis is coaxial with the rotation axis, and yn equals y/(0.5×D2) and xn equals x/B2, wherein x and y define the actual coordinates of an impeller front shroud arcuate inner face, and D2(which is the impeller outside diameter) is 712 mm, and B2 (which is the impeller outlet width) is 82 mm.

An impeller for use in a centrifugal pump, the pump including a pump casing having a chamber therein, an inlet for delivering material to be pumped to the chamber and an outlet for discharging material from the chamber, the impeller being mounted for rotation within the chamber when in use about a rotation axis, the impeller including a front shroud and a back shroud, each having a main inner face in a plane substantially at right angles to the rotation axis and a plurality of pumping vanes therebetween, each pumping vane having a leading edge in the region of an impeller inlet and a trailing edge, wherein the back shroud further includes a nose having a curved profile with a nose apex in the region of the rotation which extends towards the front shroud wherein the curved profile is defined by the following:

• yn=−66.6742503139xn5+103.3169809752xn4−60.6233286019xn3+17.0989215719xn2−2.9560300900x+0.5424661895
• where the yn axis is in the plane of the back shroud main inner face and the xn axis is coaxial with the rotation axis, and yn equals y/(0.5×D2) and xn, equals x/B2, wherein x and y define the actual coordinates of an impeller back shroud further including a nose having a curved profile, and D2 (which is the impeller outside diameter) is 712 mm, and B2 (which is the impeller outlet width) is 82 mm.

An impeller for use in a centrifugal pump, the pump including a pump casing having a chamber therein, an inlet for delivering material to be pumped to the chamber and an outlet for discharging material from the chamber, the impeller being mounted for rotation within the chamber when in use about a rotation axis, the impeller including a front shroud and a back shroud, each having a main inner face in a plane substantially at right angles to the rotation axis and a plurality of pumping vanes therebetween, each pumping vane having a leading edge in the region of an impeller inlet and a trailing edge, wherein the front shroud has an arcuate inner face in the region of the impeller inlet, the arcuate inner face has a profile defined by the following:

• yn=−0.2556639974xn5+2.6009971578xn4−10.5476726720xn3+21.4251116716xn2−21.9586498788x+9.5486465528
• where the yn, axis is in the plane of the back shroud main inner face and the n, axis is coaxial with the rotation axis, and yn, equals y/(0.5×D2) and xn equals x/B2, wherein x and y define the actual coordinates of an impeller front shroud arcuate inner face, and D2 (which is the impeller outside diameter) is 776 mm, and B2 (which is the impeller outlet width) is 98 mm.

An impeller for use in a centrifugal pump, the pump including a pump casing having a chamber therein, an inlet for delivering material to be pumped to the chamber and an outlet for discharging material from the chamber, the impeller being mounted for rotation within the chamber when in use about a rotation axis, the impeller including a front shroud and a back shroud, each having a main inner face in a plane substantially at right angles to the rotation axis and a plurality of pumping vanes therebetween, each pumping vane having a leading edge in the region of an impeller inlet and a trailing edge, wherein the back shroud further includes a nose having a curved profile with a nose apex in the region of the rotation which extends towards the front shroud wherein the curved profile is defined by the following:

• yn=−74.2097253182xn5+115.5559502836xn4−67.8953477381xn3+19.1100516593xn2−3.2725057764x+0.5878323997
• where the yn axis is in the plane of the back shroud main inner face and the xn axis is coaxial with the rotation axis, and yn equals y/(0.5×D2) and xn, equals x/B2, wherein x and y define the actual coordinates of an impeller back shroud further including a nose having a curved profile, and D2 (which is the impeller outside diameter) is 776 mm, and B2 (which is the impeller outlet width) is 98 mm.