Screw Pump Liner Bending with Rotors to Reduce Gap
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Solution Overview
Problem
Screw pumps face efficiency losses due to large gaps between rotors and liners caused by rotor shaft bending under hydraulic forces, leading to backflow and reduced pump capacity.
Innovation Solution
A replaceable liner configured to bend and pivot in unison with the rotors, reducing the gap between the rotor and liner surfaces by utilizing differential pressure-induced axial forces, thereby minimizing slippage and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the liner is designed with a larger gap to accommodate rotor shaft bending, then the reliability of the pump is improved, but the pump efficiency deteriorates due to increased backflow
Solution Approach 1:
The liner is designed with flexible support structures that allow it to dynamically adjust its position and bend along with the rotor shaft during operation. This dynamic adaptation enables the liner to maintain optimal alignment with the rotors even when shaft bending occurs, preventing excessive gaps and backflow while accommodating reliability concerns
Solution Approach 2:
The stiffness of the liner support structures is carefully engineered to allow controlled bending of the liner. By adjusting the flexibility parameters of the support structures, the system allows the liner to deform in response to rotor shaft bending, maintaining tight clearance without requiring excessive initial gap
2Loss of energy
If the gap between rotors and liner is reduced to improve pump efficiency, then the pump efficiency is improved, but the reliability deteriorates due to inability to accommodate rotor shaft bending
Solution Approach 1:
The liner transitions from a static component to a dynamic one that can bend and adapt to rotor shaft deflection. The flexible support structures enable the liner to move with the rotors, maintaining tight clearance for high efficiency while accommodating shaft bending for reliability
Solution Approach 2:
The liner is designed with flexible characteristics, allowing it to bend and deform elastically in response to rotor shaft bending. This flexibility enables the liner to maintain close contact with the rotors during operation, achieving both high efficiency and reliability
3Device complexity
If a fixed liner design is used to simplify the structure, then the device complexity is reduced, but the adaptability deteriorates due to inability to match rotor bending
Solution Approach 1:
The liner incorporates flexible support structures that enable it to dynamically adapt to rotor shaft bending without requiring complex active control systems. This passive dynamic adaptation achieves high adaptability while maintaining relatively simple structure
Solution Approach 2:
The liner automatically adjusts its position and shape in response to rotor shaft bending through its flexible support structures, without requiring external control systems or complex mechanisms. The system self-adapts to maintain optimal clearance
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 configuration significantly reduces internal slippage and increases pump efficiency by maintaining a smaller consistent gap between the rotor and liner, enhancing the pump's capacity and performance.
Implementation Method 1
utilizing the axial forces created by the differential pressure experienced by the screw pump during use
Implementation Method 2
the liner is arranged and configured to bend and/or pivot to follow the bending of the rotors
Data Source
AI summary
An improved screw pump such as, for example, a twin screw pump is disclosed. In one embodiment, the screw pump includes a casing, first and second intermeshing rotors, and a liner positioned between the first and second rotors and the casing. In use, the liner is arranged and configured to bend and/or pivot in unison with the first and second rotors under the axial hydraulic pressure experienced by the screw pump during use. In one embodiment, the liner may be arranged and configured to include an asymmetric axial stiffness to facilitate bending of the liner. In another embodiment, the liner may be arranged and configured in multiple segments, the segments being arranged and configured to pivot to approximate the bending of the rotor shafts.