Cannula Clamping Ring Prestress for Stable Blood Pump Connection

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Solution Overview

Problem

Existing cannula systems face challenges in establishing a quick, easy, and secure connection with other hollow bodies, particularly in medical applications where vascular prostheses are used, requiring a solution that simplifies and hastens the connection process while ensuring safety and stability, especially when dealing with flexible materials.

Innovation Solution

A cannula system featuring a tube element with a clamping ring and sealing ring that prestresses the front end to widen the inlet opening, allowing for a detachable and mechanically stabilized connection with a hollow body, facilitated by a manual operating element that transmits forces through the clamping ring, enabling easier and controlled insertion with improved sealing and reduced thrombus formation risk.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the tube element is made from soft and flexible material, then the cannula is more comfortable and easier to insert, but the connection to the hollow body becomes less stable and harder to control

Engineering Contradiction:
Improveease of insertionVSAvoidconnection stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The cannula is divided into functionally distinct segments: a soft tube element for insertion comfort and a rigid clamping ring for connection stability. This segmentation allows each part to optimize its properties independently - the tube element remains flexible while the clamping ring provides structural rigidity for stable connection to the hollow body

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cannula combines materials with different mechanical properties - a soft, flexible tube element material (such as medical-grade polymer) and a rigid clamping ring material. This composite construction enables the cannula to simultaneously achieve ease of insertion through the flexible tube and connection stability through the rigid clamping ring

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If the inlet opening is enlarged for easier connection, then the connection process is simplified, but the structural integrity and sealing capability are compromised

Engineering Contradiction:
Improveease of connectionVSAvoidsealing capability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The clamping ring prestresses the tube element in advance to widen the inlet opening before connection is made. This preliminary action prepares the tube element for easy connection while the sealing ring is subsequently positioned to ensure proper sealing, thus achieving both ease of connection and sealing reliability

Inventive Principle:
Principle #10Preliminary action

3Loss of time

If a detachable connection is used for quick connection, then the connection time is reduced, but the mechanical stability and security of the connection are reduced

Engineering Contradiction:
Improveconnection timeVSAvoidconnection stability
Core Design Contradiction:
Loss of timeVSStability of the object's composition

Solution Approach 1:

The clamping ring is firmly connected to the tube element and automatically prestresses it upon insertion, without requiring external tools or complex mechanisms. This self-service action enables quick connection while maintaining mechanical stability through the inherent prestressing force of the clamping ring

Inventive Principle:
Principle #25Self-service

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 proposed cannula system enables rapid, secure, and controlled connection to hollow bodies, enhancing the stability of the cannula and reducing the risk of thrombus formation, while allowing for efficient liquid conduction, particularly in blood-based applications.

Implementation Method 1

In a basic state of the cannula, in which no external forces act on the front end region of the tube element and on the clamping ring, the tube element is biased by a radially outward (internal) force exerted by the clamping ring on the front end region of the tube element. The tube element is elastically widened by this pretension

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the sealing ring is positioned such that it axially overlaps the front end portion of the tube element and is located axially rearward of the clamping ring

Methodology Applied
Scientific EffectContact pressure sealing: Pressure Increase

Data Source

PatentEP3329950B1Cannula, cannula system and blood pump system
Publication Date: 2019.09.04 BERLIN HEART GMBH
  • EP3329950B1 patent drawingFigure 1~2
  • EP3329950B1 patent drawingFigure 3
  • EP3329950B1 patent drawingFigure 4A~4B

AI summary

The invention relates to a cannula (7) for conveying a liquid, in particular blood, comprising a tube element (9) with a front end region (11) and a rear end region, wherein a channel (10) extends from the front end region (11) of the tube element (9) to the rear end region of the tube element (9) through the tube element (9), a clamping ring (19), wherein the clamping ring (19) axially overlaps the front end region (11) of the tube element (9) and is firmly connected to the front end region (11) of the tube element (9), wherein in a basic state of the cannula (7), in which no external forces act on the front end region (11) of the tube element (9) and on the clamping ring (19), the tube element (9) is pre-tensioned by a radially outward force exerted by the clamping ring (19) on the front end region (11) of the tube element (9).The invention also relates to a cannula system (2) and a blood pump system (1) with such a cannula (7).