Bellows Pump Layout for Portable Automated Peritoneal Dialysis
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Solution Overview
Problem
Existing automated peritoneal dialysis (APD) systems are cumbersome, costly, and require significant patient effort and space for disposable sets, limiting their portability and efficiency.
Innovation Solution
An APD system utilizing a bellows pump with a disposable set that includes a bellows connected to a common input/output line splitting into separate lines, actuated by a motor-driven rack and pinion mechanism, with pressure control mechanisms to ensure accurate fluid delivery and removal, and a control unit to manage the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional APD systems use disposable sets with multiple separate containers and tubing, then fluid delivery and removal functions are achieved, but device complexity and space requirements increase
Solution Approach 1:
The patent combines multiple separate containers and tubing lines into a single integrated bellows structure with internal compartments. The bellows integrates fresh dialysate storage, waste collection, and fluid transfer functions that were previously distributed across multiple separate components, thereby reducing device complexity while maintaining fluid delivery reliability through unified pressure control
Solution Approach 2:
The bellows structure serves multiple functions simultaneously: it acts as a pump for fluid delivery, a reservoir for fresh dialysate, a collection bag for waste fluid, and a pressure regulation device. This multi-functionality eliminates the need for separate dedicated components for each function, reducing overall system complexity
2Area of stationary object
If traditional APD systems use multiple separate containers and tubing, then complete fluid management is achieved, but space requirements and patient portability options increase
Solution Approach 1:
The bellows structure contains nested compartments where fresh dialysate and waste fluid are stored in concentric or adjacent chambers within the same physical structure. This nesting arrangement allows complete fluid management functionality to be achieved within a compact footprint, reducing space requirements while maintaining all necessary functions for portability
3Productivity
If manual CAPD procedures are used, then dialysis treatment is provided, but significant patient time and effort are required
Solution Approach 1:
The bellows system provides self-service through automatic fluid delivery and removal operations. The integrated structure enables the system to autonomously control fluid flow between compartments using pressure differentials created by bellows expansion and compression, eliminating the need for manual patient operations while maintaining efficient treatment delivery
4Productivity
If automated APD machines are used, then treatment efficiency improves, but device complexity and cost increase
Solution Approach 1:
The patent extracts the complex automated control mechanisms from the fluid management system and separates them into the external cycler machine, while the disposable bellows set contains only the passive integrated structure. This extraction reduces the complexity of the disposable component while maintaining automated treatment efficiency through the cycler's control of bellows expansion and compression
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 system provides a compact, cost-effective, and efficient APD solution with precise pressure and volumetric control, reducing patient effort and space requirements, enabling portability and improved treatment efficacy.
Implementation Method 1
The bellows may be actuated by a linear actuator, e.g., a motor-driven rack and pinion
Implementation Method 2
Waste, toxins and excess water pass from the patient's bloodstream, through the capillaries in the peritoneal membrane, and into the dialysis fluid due to diffusion and osmosis
Implementation Method 3
A diffusive gradient occurs across the semi-permeable dialyzer between the blood and an electrolyte solution called dialysate or dialysis fluid to cause diffusion
Data Source
AI summary
A peritoneal dialysis system includes: a bellows; a common inlet/outlet fluid receptacle in fluid communication with the bellows; a plurality of fluid lines in fluid communication with the common inlet/outlet line; a linear actuator positioned and arranged to expand and compress the bellows; a plurality of valves positioned and arranged to allow or occlude flow through the plurality of fluid lines to or from the bellows; and a control unit configured to control the linear actuator and the plurality of valves.