Centrifugal pump having a radial impeller
A centrifugal pump includes a radial impeller surrounded by a housing. The housing has a channel associated with a front side space between a cover of the impeller and the casing. Flow is led through the channel from a pressure region of the pump to a radial gap at a suction region of the pump. The flow in the channel reduces angular momentum and results in an increase in pressure in the front side space which acts of in the cover side of the impeller to offset axial force from a rear side of the impeller.
1. A centrifugal pump, comprising:
a casing, the casing including an inlet-side wall extending radially between a pump inlet and a pump outlet; and
a radial impeller surrounded by the casing,
wherein
the casing includes a channel configured to guide a flow from a front impeller side space, the channel being formed between the inlet-side wall of the casing and a casing part, the casing part being located between a cover side of the radial impeller and the inlet-side wall of the casing,
the front impeller side space is located between the cover side of the impeller and the casing,
the casing part includes an axial section aligned parallel to an impeller rotation axis connected to a radially outer end of the casing part,
the axial section of the casing part is not in contact with the casing in a region of the casing facing radially inward toward the axial section, and
a surface of the region of the casing facing radially inward toward the axial section of the casing part has the same radius from the impeller rotation axis as a region of the casing facing radially inward toward the radially-outer end of the impeller.
2. The centrifugal pump as claimed in claim 1 , wherein
the flow enters the channel from the front impeller side space through a radial gap between the axial section of the casing part and the region of the casing facing radially inward toward the axial section.
3. The centrifugal pump as claimed in claim 2 , wherein
the channel has a radial section extending in a radial direction.
4. The centrifugal pump as claimed in claim 3 , wherein
the impeller has a cover shroud at the cover side.
5. The centrifugal pump as claimed in claim 4 , wherein
at least a portion of the radial section of the channel is arranged parallel to the cover shroud.
6. The centrifugal pump as claimed in claim 4 , wherein
the radial gap is a sealing gap.
7. The centrifugal pump as claimed in claim 6 , wherein
the centrifugal pump has a split ring seal arrangement which includes the sealing gap.
8. The centrifugal pump as claimed in claim 7 , wherein
the channel guides the flow on the impeller side to a region adjacent to the split ring seal arrangement.
9. The centrifugal pump as claimed in claim 8 , wherein
the channel is delimited by a casing part having a generally L-shaped cross-sectional profile.
10. The centrifugal pump as claimed in claim 9 , wherein
the casing part is pot-shaped or bell-shaped.
11. The centrifugal pump as claimed in claim 10 , wherein
a flow region in the front impeller side space has a radial speed profile with an S-shaped curve.
12. The centrifugal pump as claimed in claim 1 , wherein
a flow region in the front impeller side space has a radial speed profile with an S-shaped curve.
13. The centrifugal pump as claimed in claim 11 , wherein
a flow region in the front impeller side space has a tangential speed profile that is largely constant.
14. The centrifugal pump as claimed in claim 12 , wherein
a flow region in the front impeller side space has a tangential speed profile that is largely constant.
15. The centrifugal pump as claimed in claim 1 , wherein
a flow region in the front impeller side space has a tangential speed profile that is largely constant.
16. The centrifugal pump as claimed in claim 1 , wherein
at least a portion of the channel has a ring-shaped cross-section.
17. The centrifugal pump as claimed in claim 8 , wherein
at least a portion of the channel has a ring-shaped cross-section.