Bio-pharmaceutical Hose Composite Structure
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Solution Overview
Problem
Existing bio-pharmaceutical hoses face challenges with the innermost surface degradation due to steam cleaning, lack of flexibility, kinking resistance, and vacuum resistance, while also being difficult to handle and attach to mechanical couplings.
Innovation Solution
A hose design featuring a fluoropolymer inner tubular layer with a conductive carbon additive, a silicone outer layer formed through cross-head extrusion, and an optional reinforcement layer with a wire braid, providing a smooth, durable, and flexible structure with enhanced vacuum resistance and ease of handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a silicone material is used for the innermost layer of the hose, then flexibility and kink resistance are improved, but the innermost surface becomes contaminated and degraded quickly over time due to repeated steam cleaning
Solution Approach 1:
The hose employs a composite structure with an innermost layer of fluoropolymer material (such as PTFE) that provides chemical inertness and resistance to steam cleaning degradation, combined with an outer layer of silicone material that provides flexibility and kink resistance. This composite construction allows each material to perform its optimal function without compromising the other.
2Reliability
If a heavy or thick wall of fluoropolymer material is used for the innermost layer, then a smooth innermost surface is achieved, but the hose becomes relatively heavy and difficult to handle
Solution Approach 1:
The hose uses a thin-walled fluoropolymer inner layer (0.005 to 0.040 inches) that maintains surface smoothness and chemical resistance, combined with a silicone outer layer (0.020 to 0.250 inches) that provides the necessary mechanical strength and flexibility. This composite structure achieves the desired performance with reduced overall weight compared to using thick fluoropolymer alone.
3Reliability
If a reinforcement layer made of heavy helix wire is used to achieve vacuum resistance, then vacuum resistance is improved, but the hose becomes relatively stiff and requires large force to flex or bend
Solution Approach 1:
The hose achieves vacuum resistance through the inherent properties of the fluoropolymer-silicone composite structure and the convoluted outer surface geometry, eliminating the need for heavy wire reinforcement. The silicone layer provides sufficient structural support while maintaining flexibility and ease of handling.
4Reliability
If the innermost surface is sterilized frequently by passing pressurized superheated steam through the hose, then sterilization is achieved, but the innermost surface degrades over time
Solution Approach 1:
The fluoropolymer material (such as PTFE) used in the innermost layer is chemically inert and resistant to degradation from superheated steam sterilization processes. This allows the hose to withstand frequent sterilization cycles without compromising the integrity or smoothness of the innermost surface, maintaining both sterilization capability and surface durability.
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 hose maintains long-lasting purity and flexibility, resists kinking and steam permeation, and offers high tensile and hoop strength, while being easy to handle and attach to mechanical couplings, thus addressing the limitations of prior art hoses.
Implementation Method 1
By utilizing a liquid silicone and subsequently curing the liquid silicone to a solid state, the liquid silicone can penetrate the gaps of the reinforcement layer and, upon curing, can adhere relatively strongly to the outer surface of the inner silicone layer.
Implementation Method 2
The outer surface of the tubular layer may first be modified by various treatments or chemicals to facilitate the adhesion of the silicone layer thereto.
Data Source
AI summary
A hose for use in bio-pharmaceutical applications includes an innermost tubular layer made from a fluoropolymer material. The tubular layer has an inner, relatively smooth and pure surface that defines an opening for transfer of various media. A layer of silicone is disposed next to an outer surface of the innermost tubular layer through use of, for example, an extrusion method. The outer surface of the tubular layer may first be modified by various treatments or chemicals to facilitate the adhesion of the silicone layer thereto. The silicone material may be solid or foamed. A reinforcement layer may be disposed adjacent to an outer surface of the silicone layer. The reinforcement layer may be formed of a wire braid having gaps. An outer jacket of silicone may be attached to the reinforcement layer and to the inner silicone layer through the gaps in the reinforcement layer.