Balloon Seal Stress Reduction via Load Sharing Member
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Solution Overview
Problem
Balloon catheters face high failure rates due to excessive hoop stress on the seal portion, particularly at high pressures, and in balloons with non-tapering shoulder geometries that lead to increased stress on adjacent seals.
Innovation Solution
The introduction of a load sharing member with a stepped or tapered geometry, using materials like expanded polytetrafluoroethylene (ePTFE) and structural reinforcements, to reduce stress on the seal portion by offsetting the outer and inner edges of the body and seal portions and incorporating less distensible materials or reinforcements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high balloon pressures are used for medical treatments, then treatment effectiveness is improved, but seal stress increases leading to balloon failure
Solution Approach 1:
The balloon is divided into distinct functional zones: a body portion made of distensible material for expansion, and a seal portion made of less distensible material for maintaining the seal. This segmentation allows the body to expand under high pressure while the seal maintains its integrity by resisting excessive deformation.
Solution Approach 2:
Different materials with different distensibility properties are used in different regions of the balloon. The body portion uses highly distensible material to accommodate high pressure expansion, while the seal portion uses less distensible material to maintain seal integrity under the same pressure conditions.
2Ease of manufacture
If non-tapering shoulder geometry is used in balloons, then manufacturing is simplified, but seal stress increases due to vertical shoulder walls
Solution Approach 1:
The shoulder region incorporates a tapered geometry that transitions from the body portion to the seal portion at an angle. This localized geometric modification in the shoulder region redistributes stress away from the seal while maintaining the overall simplicity of the balloon structure.
3Adaptability or versatility
If distensible materials are used in shoulder regions, then balloon compliance is improved, but shoulder geometry becomes non-tapering increasing seal stress
Solution Approach 1:
The shoulder region uses a tapered geometric configuration that maintains compliance through its angled transition while simultaneously reducing seal stress. The taper angle is specifically designed to allow material compliance while directing stresses away from the seal portion.
Solution Approach 2:
The balloon employs composite construction with different materials in different regions: distensible materials in the body for compliance, and less distensible materials in the seal portion for stress resistance. The shoulder region transitions between these materials to balance compliance and stress reduction.
Data Source
Figure 1~2A
Figure 2B~2C
Figure 3A~3C
AI summary
The present disclosure is directed toward devices, systems and method of production that reduce stress being exerted directly onto balloon seals (130) having a load sharing member (115) located at the shoulders (110) between the seals (130) and the body portion (120) of the balloon (100).