Adjustable Stator Rotor System for Eccentric Screw Pump Wear Compensation
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Solution Overview
Problem
Eccentric screw pumps face challenges in maintaining optimal tension between the stator and rotor due to wear, leading to reduced performance and increased backflow, especially under high suction conditions, and existing adjustment methods are cumbersome and lack feedback, requiring skilled operators and not adaptable to changing operating conditions.
Innovation Solution
A stator-rotor system with an adjusting mechanism comprising two distance-variable adjustment elements that change the cross-section and length of the elastomer part, allowing for dynamic adjustment of pretensioning between the stator and rotor, coupled with a control system that uses sensors to optimize operating parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stator is made from elastic material to compensate wear, then the contact force is reduced, but the pump performance declines
Solution Approach 1:
The stator is designed with an adjustable diameter that can be dynamically changed during operation. The stator casing includes adjustment elements (screws, nuts, or wedges) that allow the stator diameter to be increased or decreased, enabling the system to adapt to wear conditions while maintaining optimal pump performance. This dynamic adjustment resolves the contradiction by allowing the stator to compensate for wear without permanently degrading pump performance.
Solution Approach 2:
The invention changes the physical parameter of the stator diameter to compensate for wear. By adjusting the stator diameter (increasing it when wear occurs), the system maintains the necessary contact force between stator and rotor while compensating for material loss. This parameter change allows the pump to maintain its performance characteristics even as the stator wears over time.
2Reliability
If tensioning devices are distributed over the entire axial length, then the stator-rotor system weight increases considerably
Solution Approach 1:
The invention extracts the tensioning function from multiple distributed devices and concentrates it into a single tensioning device located at one end of the stator. Instead of having tensioning devices distributed along the entire axial length, the design uses one tensioning device that applies force to the free end of the stator, achieving adequate tension distribution through the stator's elastic properties without the weight penalty of multiple devices.
Solution Approach 2:
The single tensioning device serves multiple functions: it provides the necessary tension to the stator, allows for diameter adjustment, and compensates for wear. By combining these functions into one device rather than requiring separate mechanisms distributed along the stator length, the system reduces weight while maintaining reliability.
3Reliability
If multiple tensioning devices are used for readjustment, then all devices have to be individually tightened up
Solution Approach 1:
The invention merges the adjustment function into a single location. Instead of having multiple independent tensioning devices that must each be individually adjusted, the design uses one tensioning device with adjustment elements (screws, nuts, or wedges) concentrated at one end of the stator. This allows the operator to adjust the stator diameter by manipulating a single mechanism rather than coordinating multiple devices, significantly simplifying the adjustment process while maintaining precision.
4Reliability
If the stator diameter is changed to adapt tension, then the cross-section and length of elastomer part are changed
Solution Approach 1:
The invention makes the stator diameter dynamic rather than fixed. The stator casing includes adjustment mechanisms that allow the diameter to be changed during operation or maintenance periods. This dynamic capability enables the system to adapt the tension between stator and rotor by changing the stator diameter, accepting that the elastomer cross-section and length will change as a consequence of this diameter adjustment.
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 solution enables easy compensation for stator wear, minimizes backflow, and adapts to varying operating conditions, improving energy efficiency and reducing breakaway torques, while ensuring consistent sealing and reducing maintenance costs.
Implementation Method 1
a stator with an internal thread... comprising a support element, in particular a stator casing, and an elastomer part, wherein the elastomer part of the stator is arranged in the support element or stator casing and does not have a fixed connection to the support element or stator casing
Data Source
AI summary
A stator-rotor system of an eccentric screw pump including a rotor with a rotor screw and a stator with an internal thread. The stator includes a support element and an elastomer part. The support element surrounds the elastomer part in sections around the whole circumference. The stator-rotor system includes a mechanism for adjusting the stator, having two adjustment elements arranged on the stator-rotor system, which are distance-variable relative to one another. In a first working position the two adjustment elements have a first distance from one another and in a second working position, a second distance. The cross-section and the length of the elastomer part of the stator in the second working position are changed compared to the cross-section and the length of the elastomer part in the first working position.