Eccentric Screw Pump Stator and Rotor Replacement

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Solution Overview

Problem

Eccentric screw pumps require frequent maintenance, particularly the replacement of elastomeric stators and rotors, which is costly and time-consuming due to the need to dismantle multiple components, complicating the process and increasing operational expenses.

Innovation Solution

The design allows for the separate replacement of the elastomeric stator and the rotor within the eccentric screw pump without dismantling the suction housing or connecting piece, utilizing a longitudinally divided stator and a detachable coupling joint with form-fitting elements for non-rotatable connections, enabling axial separation and replacement without disassembling the coupling joint.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If the stator and rotor are replaced by dismantling the suction housing and connecting piece, then the replacement can be done, but the process becomes expensive and time-consuming due to the need to dismantle multiple components

Engineering Contradiction:
Improvestator replacementVSAvoiddismantling time
Core Design Contradiction:
Ease of repairVSLoss of time

Solution Approach 1:

The stator is divided into two separate half-shells that can be removed independently from each other and from the rotor, allowing the stator to be replaced without dismantling the suction housing or connecting piece. The coupling joint is also segmented into a first joint part and a second joint part that can be separated from the rotor.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The stator half-shells are extracted from the pump assembly by removing them from the rotor in sequence, with the first half-shell being removed first and the second half-shell being removed second, allowing complete stator replacement without dismantling the suction housing or connecting piece.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of repair

If the stator is designed as a longitudinally divided stator with two half shells, then the stator can be replaced without dismantling the pump, but additional complex components are required

Engineering Contradiction:
Improvestator replacementVSAvoidstator structure
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The stator is segmented into two half-shells that can be separately removed and replaced, simplifying maintenance while adding minimal structural complexity compared to a conventional integrated stator design.

Inventive Principle:
Principle #1Segmentation

3Ease of repair

If the rotor is detachably connected to the second joint part of the coupling joint, then the rotor can be replaced without dismantling the coupling joint, but the coupling joint structure becomes more complex

Engineering Contradiction:
Improverotor replacementVSAvoidcoupling joint structure
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The coupling joint is segmented into a first joint part and a second joint part, with the rotor detachably connected to the second joint part. This allows the rotor to be replaced by separating it from the second joint part without dismantling the entire coupling joint or suction housing, adding minimal complexity to achieve significant maintenance simplification.

Inventive Principle:
Principle #1Segmentation

4Ease of operation

If additional form-fitting elements are provided for non-rotatable connections, then axial separation and replacement is enabled, but the number of components increases

Engineering Contradiction:
Improveaxial separationVSAvoidnumber of components
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

Form-fitting elements are provided locally at specific locations on the rotor and second joint part to enable non-rotatable axial connections. These localized features enable easy axial separation and replacement without requiring complex fastening mechanisms throughout the entire assembly.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2428680B1Eccentric screw pump
Publication Date: 2017.07.19 SEEPEX GMBH
  • EP2428680B1 patent drawingFigure 1
  • EP2428680B1 patent drawingFigure 2
  • EP2428680B1 patent drawingFigure 3

AI summary

Eccentric screw pump with at least one stator (1) and a rotor (2) rotatably mounted in the stator, wherein a suction housing (4) is arranged at one end of the stator and a connection nozzle (5) is arranged at the opposite end, wherein the rotor is connected within the suction housing to a coupling rod (6) or a drive shaft via a coupling joint (7), wherein the coupling joint consists of a drive-side, first joint part and a rotor-side second joint part (7b) pivotally connected to the first joint part (7a), wherein the rotor is detachably connected to the second joint part of the coupling joint. The second joint part has a rotor receptacle facing the rotor and open on the rotor side, into which the rotor end (15) can be inserted axially, forming a rotationally fixed connection.