Integral Resilient Seal Pump Design for Leakage Reduction
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Solution Overview
Problem
Existing pumps face issues with leakage and inaccuracy in flow rate due to mismatches between the housing and seal, particularly at higher pressure differences, and require adjustable sealing forces to balance friction and leakage, which complicates operation.
Innovation Solution
A pump design where the seal is formed integrally with the housing using a single injection molding process, and an optional resilient displacer pad applies additional pressure to the seal, allowing the force to adjust with fluid pressure, reducing leakage and torque requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the housing and seal are formed separately and fitted together using adhesive or 2-shot injection molding, then manufacturing flexibility is improved, but leakage between chambers occurs at higher pressure differences and rotor apex positions
Solution Approach 1:
The seal is merged with the housing to form a single integral component manufactured in one piece using injection molding. This eliminates the separate assembly step and adhesive bonding, thereby eliminating the interface where leakage occurs while maintaining manufacturing efficiency through single-shot molding processes.
2Reliability
If a higher sealing force is applied between the rotor and seal, then leakage is reduced at higher pressures, but frictional forces and torque requirements increase unnecessarily at lower pressures
Solution Approach 1:
The seal design incorporates dynamic adaptability where the sealing force automatically adjusts based on operating conditions. The integral seal structure with its specific geometric configuration allows the sealing contact pressure to self-regulate: at higher fluid pressures, the seal deforms more to increase sealing force and prevent leakage; at lower pressures, the seal maintains minimal contact force to reduce friction and torque requirements.
3Use of energy by moving object
If a lower sealing force is applied between the rotor and seal, then torque requirements are reduced, but leakage occurs between the seal and rotor at higher pressures
Solution Approach 1:
The integral seal structure incorporates dynamic sealing characteristics where the seal material and geometry are designed to automatically increase contact pressure in response to higher fluid pressures. This elastic deformation mechanism ensures adequate sealing force is generated only when needed, maintaining low torque at normal operating pressures while preventing leakage at elevated pressures.
4Reliability
If the seal is made more resilient to accommodate pressure variations, then sealing performance improves, but frictional forces increase
Solution Approach 1:
The seal design applies local quality by creating zones of different compliance within the integral structure. The seal surface in contact with the rotor is designed with specific local elasticity to maintain optimal contact, while other portions of the seal structure maintain higher rigidity. This localized resilience provides effective sealing only where needed without increasing overall frictional forces during rotor rotation.
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 eliminates leakage between chambers, ensures accurate metered flow, and allows operation at higher pressures with reduced torque and manufacturing complexity, increasing operational life and cost-effectiveness.
Implementation Method 1
A pump according to the invention includes a resilient seal formed in one piece with the housing. The resilience of the seal allows it to deform as the rotor passes behind it.
Implementation Method 2
A pump according to a second optional aspect of the invention includes a resilient displacer pad to apply a force to the seal.
Implementation Method 3
A passage to supply fluid to an under surface for urging the seal as defined in claim 1 against the rotor
Data Source
Figure 1~3
Figure 4~5
AI summary
A pump comprises a housing (10, 210, 300, 410), the housing having an interior defining a rotor path (10, 210, 300, 410), an inlet (111, 211) formed in the housing (10, 210, 300, 410) at a first position on said rotor path, an outlet (12, 212) formed in the housing (10, 210, 300, 410) at a second position on said rotor path spaced from said first position. A rotor (15, 315, 350, 415) is rotatable in the housing. At least one first surface is formed on the rotor (15, 315, 350, 415) and seals against said rotor path of the housing (10, 210, 300, 410). At least one second surface is formed on said rotor (15, 315, 350, 415) circumferentially spaced from said first surface and forms a chamber with the rotor path that travels around said rotor path on rotation of the rotor (15, 315 350, 415) to convey fluid around the housing (10, 210, 300, 410) from the inlet (111, 211) to the outlet (12, 212). A resilient seal (114, 214) is formed in one piece with the housing (10, 210, 300, 410), located on said rotor path and so extends between the outlet (12, 212) and the inlet (111, 211) in the direction of rotation of said rotor (15, 315, 350, 415) that the first rotor surface seals with, and resiliently deforms, the seal (114, 214), as the rotor (15, 315, 350, 415) rotates around the rotor path within the housing to prevent fluid flow from said outlet (12, 212) to said inlet (111, 211) past the seal. A passage (101, 201) may be provided to supply fluid to an under surface of the seal (114, 214) at a pressure that acts to urge the seal (114, 214) against the rotor (15, 315, 350, 415). The rotor path may be frustoconical with the first surface of the rotor (15, 315, 350, 415) also being frustoconical and being a mating fit with the rotor path.