Eccentric Screw Pump Stator Lining Compression for Wear Compensation
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Solution Overview
Problem
Eccentric screw pumps face challenges in compensating for wear on the stator lining during regular operation without requiring disassembly or replacement of the stator lining, which is necessary to maintain pump availability and ensure proper sealing.
Innovation Solution
The solution involves compressing the elastomeric stator lining in the direction of the pump's longitudinal axis, preventing transverse elongation outwardly, which causes the stator lining to radially elongate inwardly, thereby constricting the screw flight. This is achieved using a mobile support tube that is arranged predominantly within a recess of the stator lining, allowing for efficient compression and elongation without the need for widening the stationary support tube.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stator lining is compressed to constrict the screw flight and compensate wear, then the sealing and pump availability are improved, but the device complexity increases due to the need for support tubes and compression mechanisms
Solution Approach 1:
The mobile support tube is inserted into a recess of the stator lining, creating a nested structure where one component fits within another. This allows the compression mechanism to be integrated within the existing stator lining structure, reducing overall device complexity while maintaining the ability to compress the stator lining for wear compensation and sealing improvement
Solution Approach 2:
The stator lining is divided into functional segments: a compression region where the mobile support tube is inserted, and a screw flight forming region. This segmentation allows the compression mechanism to be localized without affecting the entire stator lining structure, reducing the complexity impact while maintaining reliability
2Force
If the stationary support tube is elongated to prevent radial outward movement during compression, then the compression effectiveness is improved, but the forces required increase significantly
Solution Approach 1:
The mobile support tube is extracted from the traditional external support structure and repositioned within the stator lining recess. This extraction allows the support function to be performed by a smaller, more efficient component that doesn't require significant elongation, thereby reducing the forces needed while maintaining compression effectiveness
Solution Approach 2:
Instead of elongating the stationary support tube radially outward to prevent stator lining movement, the invention inverts the approach by using a mobile support tube that moves longitudinally within a recess. This inversion achieves the same constraint effect with significantly lower force requirements
3Manufacturing precision
If the screw flight is constricted by compressing the stator lining, then wear compensation and sealing are improved, but the manufacturing precision requirements increase
Solution Approach 1:
The stator lining is designed with a dynamic compression capability through the mobile support tube mechanism. This allows the screw flight to be adjusted and set with high precision during operation or maintenance, improving manufacturing precision requirements while the modular design keeps the compression process manageable
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables efficient and uniform compression of the stator lining, allowing for accurate and even setting of the screw flight over its entire length, while also providing a longer compression distance, thus enhancing the pump's operational efficiency and sealing capabilities.
Implementation Method 1
compressing the elastomeric stator lining in the direction of the pump's longitudinal axis, preventing transverse elongation outwardly, which causes the stator lining to radially elongate inwardly
Implementation Method 2
if a compressive force or compression force, respectively, is now applied to the elastomeric, but incompressible, i.e. essentially volume-constant, stator lining in the direction of the screw pump longitudinal axis and if its transverse elongation in the radially outward direction is prevented at the same time, a significant transverse elongation of the stator lining occurs in the radially inward direction
Data Source
AI summary
An eccentric screw pump with a rotor, which forms a conveyor screw, and a stator, which forms a screw thread and in which the rotor circulates during a conveying operation. The stator includes a single-part or multipart stator housing, in which a stator lining made of an elastomer material is located, said lining forming the screw thread. The stator lining forms a projection at least on one side in the direction along the pump longitudinal axis, said projection protruding from the stator housing such that a free force introduction surface is formed. A force can be applied via the free force introduction surface, said force compressing the stator lining into the stator housing so that the stator lining is transversely elongated in the stator housing, leading to a constriction of the screw thread. The projection can be surrounded by a mobile support tube which is moved relative to the stator housing in the direction along the longitudinal axis of the stator housing for compression purposes.