Ceramic Stator Seal for Eccentric Screw Pump
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Solution Overview
Problem
Conventional uniaxial eccentric screw pumps face issues with abrasion resistance of lip seals made from Teflon or rubber, leading to premature wear and fluid stagnation in the sealing mechanism, making complete cleaning difficult.
Innovation Solution
The introduction of a stator seal structure with ceramic or cemented carbide secured rings and sliding seal surfaces coated with ceramics, which provide enhanced abrasion resistance and prevent fluid stagnation by ensuring a stable sealing mechanism between the housing and the stator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lip seals made from Teflon or rubber are used for sealing between housing and stator, then sealing function is achieved, but abrasion resistance deteriorates leading to premature wear
Solution Approach 1:
The patent applies composite materials by combining a metal ring structure with ceramic or cemented carbide coating layers. The metal ring provides mechanical strength and structural integrity, while the ceramic or cemented carbide coating provides superior abrasion resistance. This composite structure resolves the contradiction by maintaining sealing reliability while dramatically extending the service life of the seal in high-abrasive environments.
Solution Approach 2:
The patent changes the material parameters of the seal by transitioning from soft materials (Teflon or rubber) to hard materials (ceramic or cemented carbide coatings on metal rings). This parameter change in material hardness and abrasion resistance directly addresses the premature wear problem while maintaining the sealing function through the ring structure design.
2Reliability
If conventional seal structures are used, then sealing is provided, but fluid stagnation occurs making complete cleaning difficult
Solution Approach 1:
The patent inverts the conventional seal design by using a ring structure that creates a clearance gap between the stator and housing, rather than relying on deformable sealing material that creates dead zones. This inverted approach eliminates fluid stagnation areas while maintaining effective sealing, thereby improving cleanability without sacrificing sealing performance.
3Duration of action of stationary object
If ceramic or cemented carbide secured rings with ceramic-coated sliding surfaces are used, then abrasion resistance is enhanced, but device complexity increases
Solution Approach 1:
The patent segments the seal into distinct functional components: a metal ring providing structural support, and separate ceramic or cemented carbide coating layers providing abrasion resistance. This segmentation allows each component to be optimized for its specific function and simplifies manufacturing and replacement processes, reducing overall device complexity while maintaining high abrasion resistance.
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
The improved seal structure significantly enhances the abrasion resistance and prevents fluid stagnation, ensuring a long-term stable sealing performance even with high-abrasive fluids.
Implementation Method 1
attached with an elastic body for ensuring with an elastic force of the elastic body a contact pressure between the sliding seal surface of the stator and the sliding seal surface of the secured ring
Data Source
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AI summary
There is provided a stator seal structure in a uniaxial eccentric screw pump by which the abrasion resistance of sealing mechanisms (14a), (14b) is improved and the pumped fluid can be prevented from stagnating in the sealing mechanisms (14a), (14b). The stator seal structure is provided with a pair of sealing mechanisms (14a), (14b) for sealing between a housing (10) and an intake side end portion, and between the housing and a discharge side end portion of the stator (4). The pair of sealing mechanisms (14a), (14b) are provided with ring-shaped secured rings (15a), (15b) secured to the housing (10), respectively. The secured rings (15a), (15b) are respectively attached with elastic bodies (16a), (16b) for ensuring with elastic forces of the elastic bodies contact pressures between the sliding seal surface of the stator (4) and the sliding seal surface of the secured rings (15a), (15b) and for sealing between the secured rings (15a), (15b) and the housing (10), The secured rings (15a), (15b) are made of ceramics or cemented carbide, and the sliding seal surface of the stator (4) is coated with ceramics.