Uniaxial Eccentric Screw Pump With Variable Contact Pressure
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Solution Overview
Problem
Existing uniaxial eccentric screw pumps face issues with inconsistent contact pressure distribution between the rotor and stator, leading to inadequate sealing tightness and excessive driving force requirements.
Innovation Solution
The design incorporates a stator with a cross-sectional opening that includes a middle area with lower contact pressure and end areas with higher sealing tightness, achieved through varying elastic moduli, coating layers, and structural thickness adjustments to optimize rotor movement and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact pressure is increased to improve sealing tightness, then the sealing performance is improved, but the driving force required to rotate the rotor increases excessively
Solution Approach 1:
The stator is designed with non-uniform thickness around the insertion hole, creating different contact pressure characteristics in different regions. The thickness is smaller at the middle area and larger at the end areas, resulting in lower contact pressure at the middle and higher contact pressure at the ends. This local variation allows the rotor to experience appropriate contact pressure at different positions during rotation, maintaining sealing tightness without requiring excessively high driving force throughout the entire rotation cycle.
2Power
If the contact pressure is decreased to reduce driving force requirements, then the power consumption is reduced, but the sealing tightness deteriorates causing inappropriate fluid delivery
Solution Approach 1:
The stator employs spatially varying thickness to create region-specific contact pressure characteristics. By making the stator thickness smaller at the middle area and larger at the end areas, the design achieves lower contact pressure (reducing power consumption) at the middle region while maintaining higher contact pressure (ensuring sealing tightness) at the end regions. This local differentiation resolves the contradiction between power consumption and sealing performance.
3Reliability
If the stator thickness is increased to improve sealing tightness, then the contact pressure is increased, but the rotor movement becomes more difficult
Solution Approach 1:
The stator is designed with non-uniform thickness distribution, being thinner at the middle area and thicker at the end areas. This local variation allows the rotor to encounter lower contact pressure and easier movement at the middle region while experiencing higher contact pressure and tighter sealing at the end regions. The thickness gradient optimizes both rotor movability and sealing performance across different positions in the rotation cycle.
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 design allows for adjustable sealing tightness and driving force, ensuring smooth rotor movement with reduced friction and reliable fluid delivery.
Implementation Method 1
The stator has the insertion hole being an opening in a cross section. The opening includes a middle area having lower contact pressure at least in a middle of the middle area than at two ends of the middle area.
Data Source
AI summary
A uniaxial eccentric screw pump includes a stator having an insertion hole with an inner peripheral surface being internally threaded, and a rotor including a shaft being externally threaded and placed through the insertion hole in the stator. The stator has the insertion hole being an opening in a cross section, the opening includes a middle area and two end areas, and the middle area has lower contact pressure at least in a middle of the middle area than at two ends of the middle area.