1. An impeller suitable for use in a centrifugal pump, for handling liquid mixtures containing particulate solids the impeller including a shroud having opposed faces, an outer peripheral edge portion and a rotation axis, a plurality of pumping vanes on one of the faces of the shroud and extending away from the rotation axis each pumping vane having an outer peripheral edge portion, and a plurality of auxiliary vanes on the other face of the shroud, the auxiliary vanes of each having an outer edge portion wherein the dimension Da from the rotation axis to the outer peripheral edge portion of the shroud is greater than the dimension from the rotation axis to outer edge portion of the auxiliary vanes Db and is greater than the dimension Dc from the rotation axis to the outer peripheral edge portion of the pumping vanes.
2. (canceled)
3. An impeller according to claim 1 wherein said shroud is a back shroud.
4. An impeller according to claim 3 wherein the impeller further includes a front shroud, the pumping vanes being between the front and back shrouds and the auxiliary vanes being on the other face of one of the shrouds.
5. An impeller according to claim 3 wherein the impeller further includes a front shroud, the pumping vanes being between the front and back shrouds and the auxiliary vanes being on the other face of each of the shrouds.
6. An impeller according to claim 4 wherein the dimension Da of the front shroud is greater than the dimensions Db and Dc.
7. An impeller according to claim 4 wherein the dimension Da of the back shroud is greater than the dimensions Db and Dc.
8. An impeller according to claim 4 wherein the dimension Da of the front and back shrouds is greater than the dimensions Db and Dc.
9. An impeller according to claim 5 wherein the dimension Da of the front shroud is greater than the dimensions Db and Dc.
10. An impeller according to claim 5 wherein the dimension Da of the back shroud is greater than the dimensions Db and Dc.
11. An impeller according to claim 5 wherein the dimension Da of the front and back shrouds is greater than the dimensions Db and Dc.
12. An impeller according to claim 6 wherein Db and Dc are substantially the same.
13. An impeller according to claim 12 wherein Db and Dc are within 5% of each other.
14. An impeller according to claim 13 wherein Db is less than 0.95 Da.
15. An impeller according to claim 14 wherein DbDa is from 0.65 to 0.95.
16. An impeller according to claim 14 wherein DbDa is from 0.65 to 0.9.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An oxygen sensor comprising: a housing, a cathode, a bismuth anode, and an aqueous electrolyte comprising a polyol and a salt wherein the anode is substantially free of lead.
2. The oxygen sensor of claim 1 wherein the cathode comprises an electrically conductive material selected from the group consisting of platinum, gold, silver, palladium, rhodium, iridium and carbon plated with platinum, gold, silver, palladium, rhodium, or iridium.
3. The oxygen sensor of claim 1 wherein the cathode is carbon plated with platinum.
4. The oxygen sensor of claim 1 wherein the salt is an alkaline salt.
5. The oxygen sensor of claim 1 wherein the salt is selected from the group consisting of potassium hydroxide, sodium hydroxide, potassium acetate, and sodium acetate.
6. The oxygen sensor of claim 1 wherein the salt is potassium hydroxide.
7. The oxygen sensor of claim 1 wherein the salt is an ammonium quaternary hydroxide, R4N+OH\u2212.
8. The oxygen sensor of claim 7 wherein R is an alkyl group selected from the group consisting of methyl, ethyl, propyl, butyl, and mixtures thereof.
9. The oxygen sensor of claim 1 wherein the polyol is selected from the group consisting of glycerol, erythritol, sorbitol, ethylene glycol, and mixtures thereof.
10. The oxygen sensor of claim 1 wherein the polyol is glycerol.
11. The oxygen sensor of claim 1 wherein the polyol comprises about 20% to about 30% by volume.
12. An oxygen sensor comprising: a housing, a cathode, a bismuth anode, and an aqueous electrolyte that includes a salt and a polyol, wherein the anode is substantially free of lead.
13. The oxygen sensor of claim 12 wherein the cathode comprises an electrically conductive material selected from the group consisting of platinum, gold, silver, palladium, rhodium, iridium and carbon plated with platinum, gold, silver, palladium, rhodium, or iridium.
14. The oxygen sensor of claim 12 wherein the salt is selected from the group consisting of potassium hydroxide, sodium hydroxide, potassium acetate, and sodium acetate.
15. The oxygen sensor of claim 12 wherein the salt is potassium hydroxide.
16. The oxygen sensor of claim 12 wherein the salt is an ammonium quaternary hydroxide, R4N+OH\u2212.
17. The oxygen sensor of claim 16 wherein R is an alkyl group selected from the group consisting of methyl, ethyl, propyl, butyl, and mixtures thereof.
18. The oxygen sensor of claim 12 wherein the polyol is selected from the group consisting of glycerol, erythritol, sorbitol and ethylene glycol.
19. The oxygen sensor of claim 12 wherein the polyol is glycerol.
20. An electrochemical sensor comprising a bismuth anode and aqueous electrolyte comprising a polyol and a salt.