Check Valve Flow Path Geometry for Low-Backpressure Fluid Pumps
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Solution Overview
Problem
Conventional fluid pumps, particularly those used for biofuels, face issues with backpressure, which negatively impacts fluid delivery, especially at lower temperatures, and existing check valve assemblies do not adequately minimize this problem.
Innovation Solution
A fluid pump design incorporating a check valve assembly with a specific flow path configuration that includes a first restriction, first expansion, second restriction, and second expansion within the outlet conduit, which minimizes backpressure by varying fluid velocity and pressure through a radial flow path between the conduit and valve stem, allowing efficient fluid flow while preventing backflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional check valve assembly is used in the outlet conduit, then backflow is prevented, but backpressure is generated which negatively impacts fluid delivery
Solution Approach 1:
The flow path is segmented into multiple sections with alternating restrictions and expansions. The restriction sections create high velocity zones while expansion sections create low pressure zones, segmenting the flow control function to minimize backpressure while maintaining backflow prevention capability
Solution Approach 2:
The flow path parameters (cross-sectional area, velocity, pressure) are dynamically changed through the alternating restriction-expansion geometry. This parameter variation optimizes fluid flow characteristics to reduce backpressure while ensuring reliable backflow prevention
2Reliability
If the check valve assembly provides adequate backflow prevention, then reliability is improved, but fluid delivery efficiency deteriorates due to backpressure
Solution Approach 1:
The design converts the potentially harmful backpressure into beneficial flow characteristics. The restriction-expansion geometry transforms pressure losses into kinetic energy and vice versa, converting what would be harmful backpressure into useful flow momentum that maintains delivery efficiency
Solution Approach 2:
By changing flow parameters (velocity, pressure, cross-sectional area) through the alternating restriction-expansion sections, the system optimizes the balance between backflow prevention and fluid delivery efficiency, ensuring both reliability and productivity
3Ease of manufacture
If a simple check valve design is used, then manufacturing is easier and cost-effective, but backpressure reduction capability is insufficient
Solution Approach 1:
The check valve assembly is segmented into alternating restriction and expansion sections, creating a complex flow path geometry that reduces backpressure while remaining manufacturable through standard machining processes
Solution Approach 2:
Different sections of the flow path have different local geometries (restrictions with smaller cross-sectional areas and expansions with larger cross-sectional areas) optimized for specific functions, allowing backpressure reduction while maintaining ease of manufacture through localized feature variation
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 described fluid pump and check valve assembly significantly reduce backpressure compared to prior art, enhancing fuel delivery efficiency, particularly beneficial for biofuels at lower temperatures, while maintaining ease and cost-effectiveness in manufacturing.
Implementation Method 1
a first restriction which increases velocity of fluid passing through the flow path
Implementation Method 2
a first expansion, downstream of the first restriction, which decreases velocity of fluid passing through the flow path
Implementation Method 3
a second restriction, downstream of the first expansion, which increases velocity of fluid passing through the flow path
Implementation Method 4
a second expansion, downstream of the second restriction, which decreases velocity of fluid passing through the flow path
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A fluid pump (10) includes a housing (18); an inlet passage (34); an outlet conduit (50); a pumping element (28) within the housing (18); and a check valve assembly (52). The check valve assembly (52) includes a valve stem (54) within the outlet conduit (50) such that a flow path is created radially between the outlet conduit (50) and the valve stem (54), the valve stem (54) moving along a check valve assembly axis (56) between a closed position and an open position. The flow path includes a first restriction (68) which increases velocity of fluid passing through the flow path; a first expansion (70), downstream of the first restriction (68), which decreases velocity of fluid passing through the flow path; a second restriction (72), downstream of the first expansion (70), which increases velocity of fluid passing through the flow path; and a second expansion (74), downstream of the second restriction (72), which decreases velocity of fluid passing through the flow path.