Oval Cross-Section Tubular Insert for Peristaltic Pump
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Solution Overview
Problem
Existing tubular inserts for peristaltic pumps in extra-corporeal circuits face challenges in maintaining optimal performance and elasticity, especially with materials like PVC-TOTM, which suffer from significant flow rate reduction during prolonged use, and are costly alternatives like silicone are not economically viable.
Innovation Solution
The development of tubular inserts with an oval cross-section and specific geometric characteristics, allowing for high elasticity and minimal flow rate deterioration, using materials like PVC plasticized with TOTM, and a production method involving compression and thermal treatment to stabilize the oval shape, ensuring compatibility with peristaltic pumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PVC-TOTM material is used to replace DOP plasticizer, then cost is reduced and toxicological safety is improved, but elasticity and flow rate maintenance deteriorate significantly
Solution Approach 1:
The patent applies parameter changes by modifying the geometric parameters of the tube (oval cross-section with specific axis ratios) and thermal parameters (heating to 60-80°C during operation) to compensate for the material property changes caused by replacing DOP with TOTM plasticizer. This resolves the contradiction by maintaining elasticity through shape and temperature control rather than relying solely on material composition.
Solution Approach 2:
The patent creates a composite system combining PVC base material with TOTM plasticizer and specific geometric configuration (oval cross-section). This composite approach allows the use of safer plasticizer while compensating for its lower elasticity through the unique tube geometry and operational temperature conditions, achieving both toxicological safety and functional performance.
2Stability of the object's composition
If tube wall thickness is increased to ensure elastic recovery, then elasticity is improved, but inner diameter is reduced and flow rate is significantly altered
Solution Approach 1:
The patent employs curvature by transitioning from a circular to an oval cross-section with a specific axis ratio (major axis 1.2-1.5 times the minor axis). This geometric transformation optimizes the distribution of wall thickness and elastic properties, allowing sufficient elastic recovery without increasing overall wall thickness that would reduce the inner diameter and flow rate.
Solution Approach 2:
The patent changes the geometric parameters of the tube cross-section from circular to oval with specific axis ratios, and also changes the operational temperature parameter (heating to 60-80°C) to enhance elasticity. These parameter changes enable adequate elastic recovery while maintaining the original inner diameter and flow rate characteristics.
3Ease of manufacture
If conventional circular cross-section tube is used, then manufacturing is simpler, but elastic recovery and flow rate maintenance are insufficient during prolonged use
Solution Approach 1:
The patent applies curvature by using an oval cross-section instead of a circular one, with the major axis oriented perpendicular to the peristaltic pump's compression direction. This geometric modification enhances elastic recovery characteristics and maintains flow rate stability during prolonged use, while the manufacturing process remains relatively simple through extrusion molding with appropriate tooling.
Solution Approach 2:
The patent modifies the geometric parameter of the cross-section shape and introduces temperature parameter control (heating to 60-80°C during operation) to improve elastic recovery and flow rate maintenance. These parameter changes enable the tube to maintain performance during prolonged use while keeping manufacturing feasible through standard extrusion processes.
4Ease of operation
If tube material is made softer to allow proper compression by rollers, then compression efficiency is improved, but elastic recovery capability deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the operational temperature (heating to 60-80°C) and geometric shape (oval cross-section) to achieve optimal balance between softness for compression and elasticity for recovery. The heated state enhances material flexibility for efficient compression, while the oval geometry and cooling phase ensure adequate elastic recovery, resolving the contradiction between compression efficiency and recovery capability.
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 oval cross-section tubular inserts maintain a high flow rate with minimal deterioration over long periods, outperforming conventional PVC-TOTM inserts and approaching the performance of PVC-DOP inserts, while being cost-effective and compatible with existing peristaltic pump designs.
Implementation Method 1
the tube walls must be sufficiently rigid to allow a good elastic recovery at the end of the compression exerted by the rollers. Compression of the tube and subsequent elastic recovery thereof constitute in fact the basis for correct operation of the peristaltic pump
Implementation Method 2
a production method involving compression and thermal treatment to stabilize the oval shape
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The present invention relates to a novel type of tubular insert 28 for connecting an extra-corporeal circuit 26 to a peristaltic pump 22. This tubular insert 28 comprises a loop 32 formed by a tube portion 20; the loop 32 comprises a curve 38 which extends around an axis X. The tube 20 which forms the curve 38 has an oval cross-section with a major axis M and a minor axis m perpendicular to each other, where the major axis M is longer than the minor axis m. Finally, in the tubular insert 28 according to the invention, the minor axis m of each cross-section of the tube 20 along the curve 38 is parallel to the axis X. The invention further relates to a method for producing the tubular insert 28 and to a peristaltic pump 22 suitable for operating with tubular inserts according both to the invention and to the prior art.