Medical Stopcock Segmented Flow Path Design

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Solution Overview

Problem

Conventional medical stopcocks with arc-shaped grooves allow medical solutions to flow from the upstream port to the downstream port instead of the side tube port, causing solutions to stay in the side tube space when the valve is closed, leading to inefficiencies and potential mixing issues between vasopressor and depressor solutions.

Innovation Solution

A medical stopcock design featuring a cylindrical housing with distinct communication holes and grooves that allow solutions to flow from the upstream port to the side tube port while preventing direct flow to the downstream port, ensuring solutions are pushed through the side tube and reducing residual solution issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If an arc-shaped groove is formed continuously from the upstream port section to the downstream port section, then the flow path switching function is improved, but the medical solution flows directly to the downstream port section without entering the side tube port, causing the solution to stay in the side tube space when the valve is closed

Engineering Contradiction:
Improveflow path switching functionVSAvoidsolution flow to side tube port
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The continuous arc-shaped groove is segmented into a first flow path groove and a second flow path groove. The first groove connects the upstream port to the side tube port, while the second groove connects the side tube port to the downstream port. This segmentation ensures that when the cock is at the reference position, the medical solution flows from the upstream port through the first groove into the side tube port, rather than bypassing it entirely to reach the downstream port.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the flow path are given different properties through the two communication holes in the side tube port. The first communication hole has a larger opening area to facilitate solution flow into the side tube, while the second communication hole has a smaller opening area to control the flow from the side tube to the downstream port. This local differentiation ensures proper solution distribution.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If the valve attached to the port section for a side tube is closed, then the connector can be detached, but the medical solution stays in the internal space of the port section for a side tube or in the space formed between the connector and the port section

Engineering Contradiction:
Improveconnector detachmentVSAvoidmedical solution remaining in side tube
Core Design Contradiction:
Ease of operationVSLoss of substance

Solution Approach 1:

The design extracts the problematic continuous flow path and replaces it with a segmented flow path system that includes two distinct communication holes. This extraction of the continuous groove and replacement with controlled openings allows the first communication hole to fill the side tube space with medical solution while the second, smaller communication hole provides a controlled exit path, preventing solution from being trapped when the valve is closed.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of having the solution flow directly from upstream to downstream through a continuous groove (the conventional approach), the invention inverts the flow path by requiring the solution to first enter the side tube port through the first communication hole, then exit through the second communication hole. This inversion ensures that the side tube space is actively filled and drained rather than being bypassed, preventing solution accumulation.

Inventive Principle:
Principle #13The other way round (Inversion)

3Adaptability or versatility

If vasopressor solution and depressor solution are injected from the port section for a side tube, then the mixing function is improved, but the staying vasopressor solution may be pushed by depressor solution, causing an inconvenience

Engineering Contradiction:
Improvesolution mixing capabilityVSAvoidsolution mixing errors
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The first communication hole is designed with a larger opening area to ensure that the side tube port is completely filled with medical solution (priming action) before any injection or mixing operations begin. This preliminary filling action ensures that when vasopressor solution is subsequently injected, it displaces the priming solution in a controlled manner through the second communication hole, preventing mixing errors when depressor solution is later injected.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2832398B1Medical stopcock
Publication Date: 2017.09.06 TERUMO KK
  • EP2832398B1 patent drawingFigure 1
  • EP2832398B1 patent drawingFigure 2
  • EP2832398B1 patent drawingFigure 3

AI summary

A medical stopcock 1 includes a housing 2 and a cock 3. The housing 2 includes a cylindrical the body section 6 formed with a through-hole 6a, an upstream port section 7, a downstream port section 8, and a port section 9 for a side tube. The port section 9 for a side tube includes a first communication hole 13 and a second communication hole 14 having an opening area smaller than that of the first communication hole 13. The cock 3 includes a cylindrical section 31. The cylindrical section 31 is formed with a first flow path groove 33 communicating with the upstream port section 7 and the first communication hole 13, and a second flow path groove 14 communicating with the second communication hole 14 and the downstream port section 8.