Elastomeric Cassette Flow Channels for Peristaltic Pump Pulsation Reduction
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Solution Overview
Problem
Prior art peristaltic pumps using rotating roller heads often impart unwanted pressure pulsations due to abrupt compression of flexible tubing, which existing pulsation damping devices have not fully addressed, necessitating a solution to reduce these pulsations for improved flow consistency.
Innovation Solution
A peristaltic pump cassette with an elastomeric sheet bonded to a rigid substrate, featuring smooth, fluid-lined flow channels with constant cross-sectional areas, is used in conjunction with radially oriented rollers that compress the elastomeric channels against the substrate, eliminating the need for manual tubing connection and reducing pulsations by maintaining a consistent fluid pathway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional flexible tubing is used in peristaltic pumps, then the pump can be simple in structure, but pressure pulsations occur due to abrupt compression of the tubing
Solution Approach 1:
The patent uses an elastomeric sheet with molded flow channels instead of traditional flexible tubing. The elastomeric material provides the necessary flexibility for compression while the molded channels maintain consistent cross-sectional area, reducing pressure pulsations during roller compression.
Solution Approach 2:
The flow channels are molded with smooth, curved transitions and constant cross-sectional area throughout their length, eliminating sharp edges and abrupt direction changes. This curvature design ensures gradual fluid transition and reduces turbulence and pressure pulsations during compression.
2Ease of manufacture
If manual connection of pump tube around rotating roller head is required, then the pump can use simple components, but the operation becomes complex and time-consuming
Solution Approach 1:
The elastomeric sheet with molded flow channels integrates the function of multiple separate components (tubing, connectors, adapters) into a single piece. This eliminates the need for manual connection and disconnection of tubing segments around the roller head, simplifying operation while maintaining component simplicity.
Solution Approach 2:
The molded flow channels are designed to automatically align and interface with the roller head geometry, eliminating the need for manual positioning or connection steps. The elastomeric material's flexibility allows self-adjustment during installation, making the system easier to operate.
3Object-generated harmful factors
If tapered sections of pump tube are used, then pressure pulsations are reduced somewhat, but further reduction is needed for optimal performance
Solution Approach 1:
The elastomeric sheet provides locally optimized flow channel geometry with constant cross-sectional area in the compression zone, while maintaining flexibility of the material itself. This localized quality control in the flow channel design achieves superior pulsation reduction compared to general tapered tubing designs.
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 solution effectively minimizes pressure pulsations, ensuring a consistent and predictable fluid flow by maintaining a constant cross-sectional area throughout the fluid path, thereby enhancing the performance of peristaltic pumps in medical applications.
Implementation Method 1
peristaltic pumps work by compressing or squeezing a length of flexible tubing (sometimes between a fixed race) using a rotating roller head. As the roller head rotates, the rollers pinch off a portion of the tubing and push any fluid trapped in the tubing between the rollers in the direction of rotation.
Implementation Method 2
A cassette having an elastomeric sheet that is bonded or mechanically attached to a rigid substrate
Data Source
AI summary
A cassette having an elastomeric sheet that is bonded or mechanically attached to a rigid substrate. A flow channel is molded into the rigid substrate that corresponds to a flow channel molded into the elastomeric sheet. The cassette is used in combination with a peristaltic pump having pump head rollers that are mounted radially from the axis of rotation of the pump motor so as to compress the elastomeric flow channels against the rigid substrate during operation. The flow channels molded into the rigid substrate have smooth, fluid lines free from sharp edges and abrupt direction changes and correspond with the fluid channels molded into the elastomeric sheet so as to provide a transition region with a relatively constant cross-section over its entire length that approximates the cross-sectional area of the flow channels molded into the rigid substrate and the fluid channel molded into the elastomeric sheet so that the entire fluid path is of relatively constant cross-sectional area.