Shredding assembly for a grinder pump and centrifugal grinder pump

Patent metadata

Field	Value
Publication number	US-10947979-B2
Application number	US-201816184387-A
Country	US
Kind code	B2
Filing date	Nov 8, 2018
Priority date	Dec 4, 2017
Publication date	Mar 16, 2021
Grant date	Mar 16, 2021

Abstract

A shredding assembly for a grinder pump includes a stationary shredding ring mounted to an inlet of the pump, and a cutting device rotatable about an axial direction and fixed to a shaft of the pump. The shredding ring includes a top face, a bottom face, and a central opening extending from the top face to the bottom face and delimited in a radial direction by an inner periphery. Slots extending in the axial direction are formed in the inner periphery. The cutting device is positioned in the central opening of the shredding ring, and includes a front face and a back face. The front face includes a plurality of first cutting members extending in the axial direction and facing the slots. The back face includes a second cutting member projecting beyond the central opening with respect to the radial direction.

First claim

What is claimed:

1. A shredding assembly for a grinder pump, comprising:
a stationary shredding ring configured to be mounted to an inlet of the pump; and
a cutting device configured to rotate about an axial direction and configured to be fixed to a shaft of the pump,
the shredding ring comprising a top face, a bottom face, and a central opening extending from the top face to the bottom face and being delimited in a radial direction by an inner periphery, a plurality of slots extending in the axial direction formed in the inner periphery,
the cutting device being positioned in the central opening of the shredding ring, and comprising a front face and a back face, the front face comprising a plurality of first cutting members extending in the axial direction and facing the plurality of slots in the inner periphery, the back face of the cutting device comprising exactly two second cutting members projecting beyond the central opening with respect to the radial direction, the exactly two second cutting members being arranged diametrically opposite at an outer periphery of the cutting device.

2. The shredding assembly in accordance with claim 1 , wherein
the at least one second cutting member comprises a leading face inclined with respect to the axial direction at a rake angle of 40° to 60.

3. The shredding assembly in accordance with claim 1 , wherein
the at least one second cutting member comprises a leading edge inclined with respect to the radial direction at a cutting angle of 35° to 55°.

4. The shredding assembly in accordance with claim 1 ,
wherein
the slots are configured and arranged such that only one of the two second cutting members performs a cutting action at any moment in time during operation.

5. The shredding assembly in accordance with claim 1 , wherein
the plurality of first cutting members comprises at least one recess at the outer periphery of the cutting device, the recess forming a cutting edge.

6. The shredding assembly in accordance with claim 1 , wherein
the plurality of first cutting members comprises at least one protrusion extending from the front face of the cutting device in the axial direction.

7. The shredding assembly in accordance with claim 6 , wherein
the at least one protrusion comprises a leading face inclined with respect to the radial direction at a front angle of 20° to 26°.

8. The shredding assembly in accordance with claim 6 , wherein
the at least one protrusion comprises a leading face inclined with respect to the radial direction at a front angle of 23°.

9. The shredding assembly in accordance with claim 6 , wherein
the at least one protrusion comprises a leading face inclined with respect to the radial direction at a front angle of 18° to 28°, and the leading face of the protrusion is inclined such that a radially outer edge delimiting the leading face is ahead of a radially inner edge delimiting the leading face, when viewed in the direction of rotation.

10. A centrifugal grinder pump comprising:
a housing including the inlet for a fluid to be conveyed, and a pump outlet for discharging the fluid;
at least one impeller configured to rotate about the axial direction with the impeller being arranged in an impeller chamber;
the shaft configured to rotate the impeller; and
the shredding assembly according to claim 1 arranged at the inlet and configured to shred constituents of the fluid, the shredding ring mounted to the inlet of the pump, the cutting device connected to the shaft, and the bottom face of the shredding ring and the back face of the cutting device arranged to face the impeller chamber.

11. The centrifugal grinder pump in accordance with claim 10 , wherein
the centrifugal grinder pump is a multistage centrifugal pump, the at least one impeller comprising first and second stage impellers and the impeller chamber being a first impeller chamber and the centrifugal grinder pump including a second impeller chamber, the first stage impeller arranged in the first impeller chamber, and the second stage impeller arranged in the second impeller chamber, and centrifugal grinder pump further comprising a diffusor configured to guide the fluid from the first impeller chamber to the second stage impeller with the diffusor being arranged between the first stage impeller and the second stage impeller in the axial direction, the first stage impeller and the second stage impeller connected to the shaft in a torque-proof manner.

12. The centrifugal grinder pump in accordance with claim 11 , wherein
the diffusor is a disk-shaped diffusor delimiting both the first impeller chamber and the second impeller chamber with respect to the axial direction.

13. The centrifugal grinder pump in accordance with claim 11 , further comprising
a drive unit configured to rotate the shaft about the axial direction, the drive unit arranged within the housing, and the first stage impeller and the second stage impeller arranged between the drive unit and the shredding assembly with respect to the axial direction.

14. The centrifugal grinder pump in accordance with claim 13 , wherein
the centrifugal grinder pump is configured for a vertical operation with the shaft extending in a vertical direction, the drive unit arranged above the first stage impeller and the second stage impeller.

15. The centrifugal grinder pump in accordance with claim 10 , wherein,
the centrifugal grinder pump is a submersible pump.

16. The centrifugal grinder pump in accordance with claim 10 , wherein
the centrifugal grinder pump is a two stage pump.

17. The shredding assembly in accordance with claim 1 , wherein
the at least one second cutting member comprises a leading face inclined with respect to the axial direction at a rake angle of 45° to 55°.

18. The shredding assembly in accordance with claim 1 , wherein
the at least one second cutting member comprises a leading face inclined with respect to the axial direction at a rake angle of 50°.

Assignees

• Sulzer Management Ag

Inventors

• Burke Michael
• Mcdonald Barry
• Albadawi Abdulaleem

Classifications

• F04D13/08

  for submerged use · CPC title

• F05D2260/607

  Preventing clogging or obstruction of flow paths by dirt, dust, or foreign particles · CPC title

• F05D2250/294

  grooved · CPC title

• B02C18/0092

  for waste water or for garbage · CPC title

• F04D7/045 Primary

  with means for comminuting, mixing stirring or otherwise treating · CPC title