Extruded Elastomer Tube for Low-Migration Roller Pumping
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Solution Overview
Problem
Flexible tubes used in roller pumps for applications like food manufacturing face issues with resin composition migration and inadequate compression recovery, leading to fluid contamination and reduced performance.
Innovation Solution
A flexible tube with a styrene-based elastomer as the main component, featuring an arithmetic average roughness of 1.5 μm or less on the inner surface, a maximum height of 7 μm or less, and a specific roughness ratio, produced through extrusion molding with a draw down ratio of 0.8 to 1.1, enhancing non-migration and compression recovery properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional flexible tubes are used in roller pumps, then they can perform basic fluid transport, but resin composition migrates into the fluid causing contamination
Solution Approach 1:
The patent changes the surface roughness parameters of the flexible tube by controlling the draw down ratio during extrusion molding to be 0.8 to 1.1, achieving an arithmetic average roughness Ra of 1.5 μm or less and maximum height Rz of 7 μm or less. This parameter optimization reduces resin migration and prevents fluid contamination while maintaining flexibility and compression recovery properties.
2Productivity
If the flexible tube is repeatedly compressed in roller pumps, then fluid transport is achieved, but compression recovery properties deteriorate
Solution Approach 1:
The patent optimizes the draw down ratio parameter during extrusion molding to a specific range of 0.8 to 1.1, which creates controlled surface roughness (Ra ≤ 1.5 μm, Rz ≤ 7 μm) that enhances the tube's elastic recovery capability. This allows the flexible tube to maintain excellent compression recovery properties even after repeated compression cycles in roller pump operations.
3Productivity
If extrusion molding is performed with high draw down ratio, then production efficiency is improved, but surface roughness increases causing resin migration
Solution Approach 1:
The patent identifies and controls the draw down ratio parameter within the optimal range of 0.8 to 1.1 during extrusion molding. This precise parameter control achieves the dual objective of maintaining acceptable production efficiency while producing flexible tubes with inner surface roughness (Ra ≤ 1.5 μm, Rz ≤ 7 μm) that prevents resin migration and fluid contamination.
Data Source
AI summary
A flexible tube has a styrene-based elastomer as a main component, which is formed by extrusion molding so that a draw down ratio in an inner diameter will be 0.8 to 1.1, and an arithmetic average roughness Ra of an inner surface of the flexible tube is 1.5 μm or less, and a maximum height Rz of an inner surface of the flexible tube is 7 μm or less, and an amount of evaporation residue except for heptane in the flexible tube, which is measured in accordance with a test method in Standards and criteria for food and food additives, etc. (Ministry of Health, Labour and Welfare Notification No. 380 on Dec. 4, 2020), is 30 μg/ml or less, and a ratio of the maximum height Rz to the arithmetic average roughness Ra of an inner surface of the flexible tube Rz/Ra is 3.9 or less.