Single-Piece Check Valve Corrosion Management

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Solution Overview

Problem

Existing check valves in hemodialysis devices fail to withstand harsh environments of high temperatures, corrosive fluids, and high-pressure pulsating flows, leading to frequent replacements and alignment issues, and are prone to corrosion and leakage due to multiple components and symmetrical designs.

Innovation Solution

A single-piece check valve with a sacrificial anode and self-tapping screw thread connections, featuring a frustoconical protrusion for easy alignment, a helical spring, and an o-ring for self-cleaning fluid flow, which includes a poppet and a washer made of different materials to manage corrosion and prevent backflow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a check valve is designed with multiple components (spring, poppet, valve body) to maintain sealing capability, then the sealing function is improved, but the reliability deteriorates due to corrosion at multiple connection points and component failure

Engineering Contradiction:
Improvesealing capabilityVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the valve body, poppet, and spring into a single integrated check valve assembly. The valve body is formed as a unitary structure with the poppet and spring embedded within, eliminating multiple separate components that could corrode or fail independently. This integration reduces the number of connection points where leakage could occur while maintaining the sealing function through the unified design.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If a check valve uses symmetrical design for ease of installation, then the ease of operation is improved, but the ease of operation deteriorates because users cannot determine correct alignment

Engineering Contradiction:
Improveinstallation easeVSAvoidalignment information
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The patent introduces asymmetry through flow direction indicators (arrows) molded into the valve body and a non-circular cross-section of the valve. These asymmetric features provide visual information about the correct installation orientation, allowing users to quickly determine proper alignment without complex markings or symmetrical confusion. The asymmetric design maintains ease of installation by being intuitively recognizable.

Inventive Principle:
Principle #4Asymmetry

3Duration of action of stationary object

If check valve components are made of corrosion-resistant materials to withstand harsh environments, then the duration of action is improved, but the cost increases due to specialized materials

Engineering Contradiction:
Improveservice lifeVSAvoidmaterial cost
Core Design Contradiction:
Duration of action of stationary objectVSLoss of substance

Solution Approach 1:

The patent employs a sacrificial anode made of less expensive, more corrosion-prone material that is intentionally designed to corrode first, protecting the more expensive corrosion-resistant components (valve body, poppet, spring). The sacrificial anode is a consumable component that extends the service life of the main valve assembly by sacrificing itself, providing economic protection against material costs.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Adaptability or versatility

If check valves are designed with multiple connection points for assembly, then the adaptability is improved, but the reliability deteriorates due to multiple leakage points

Engineering Contradiction:
Improveassembly flexibilityVSAvoidleakage resistance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent integrates the connection ports directly into the unitary valve body structure, eliminating separate connection components. The valve body is molded as a single piece with built-in connection features, reducing the number of assembly joints and potential leakage points while maintaining adaptability for fluid flow path integration. This merging approach preserves assembly flexibility through integrated design while improving leakage resistance.

Inventive Principle:
Principle #5Merging (Combining)

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 solution extends the lifespan of check valves by managing corrosion, reducing maintenance downtime, and ensuring proper alignment, while the self-cleaning mechanism prevents particulate buildup and leakage, enhancing the reliability of hemodialysis devices.

Implementation Method 1

a sacrificial anode washer disposed at an end of the spring, the sacrificial anode washer being configured to corrode at a rate faster than the spring

Methodology Applied
Scientific EffectGalvanic corrosion: Crevice Corrosion

Implementation Method 2

In response to a pressure of a fluid flow from the inlet end to the outlet end exceeding a tension of the spring, the spring may be configured to compress such that the second end of the poppet and the o-ring unseal the valve seat

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 3

The o-ring may be configured with respect to the valve assembly, such that the fluid flow exiting the check valve forms a quick spray against the valve seat in a self-cleaning manner

Methodology Applied
Scientific EffectFluid spray: Fluid Spray

Data Source

PatentEP3574241A1Check valve and method of forming a check valve
Publication Date: 2019.12.04 FRESENIUS MEDICAL CARE HOLDINGS INC

AI summary

Check valves and methods for forming check valves according to exemplary embodiments of the present invention may include a hollow body. The hollow body may include an inlet end and an outlet end, the inlet end having a first connector and the outlet end having a second connector. A connecting projection may be disposed along a length of an outer surface. A protrusion may extend from the outer surface, the protrusion corresponding to a direction of fluid flow.