Gravity-Based Peritoneal Dialysis Fluid Control Without Pumps
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Solution Overview
Problem
Current APD devices are expensive, cause patient discomfort due to excessive pressures, have large footprints, are difficult to transport, require heavy lifting, and suffer from issues like free fluid flow, low flow rates, and unreliable load cells, among other challenges.
Innovation Solution
A gravity-based APD system with solenoid-operated pinch valves, modular enclosures, and load cells protected from overload, using a reusable drain container and tool-free assembly, along with a design that minimizes lifting and interference, ensuring accurate fluid delivery and portability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active pumping APD devices are used, then fluid delivery control is improved, but device cost and complexity increase
Solution Approach 1:
The patent replaces the mechanical pump system with a gravity-based fluid delivery system. The pump is eliminated and replaced by using gravity as the driving force for fluid flow, controlled by electronically actuated pinch valves that occlude or release tubing to regulate flow rates, thereby reducing mechanical complexity while maintaining delivery control.
Solution Approach 2:
The patent uses pneumatic actuators (solenoids) to control the pinch valves. Electrical signals from the microcontroller actuate the solenoids, which mechanically compress the elastomeric tubing to occlude flow, providing precise fluid control without mechanical pumps or complex hydraulic systems.
2Reliability
If active pumping APD devices are used, then fluid delivery control is improved, but device cost increases
Solution Approach 1:
The patent eliminates expensive mechanical pump components and replaces them with simple gravity-based flow control using electronically actuated pinch valves. This substitution dramatically reduces bill of materials costs while maintaining adequate fluid delivery control for peritoneal dialysis therapy.
Solution Approach 2:
The patent employs disposable tubing sets with integrated pinch valves and cassettes that are discarded after a single use. This eliminates the need for expensive, complex, and difficult-to-clean reusable pump mechanisms, reducing both initial device cost and ongoing maintenance expenses.
3Ease of manufacture
If gravity-based APD devices are used, then device cost is reduced, but device height increases
Solution Approach 1:
The patent transitions from a horizontal layout to a vertical configuration, stacking functional components (pump, reservoir, control unit) vertically along a pole structure. This dimensional change allows the device to achieve necessary height for gravity-based flow while minimizing floor footprint and improving space utilization in patient environments.
Solution Approach 2:
The patent incorporates an adjustable-height pole with movable brackets that allow dynamic repositioning of the reservoir and control unit to optimal heights for individual patients and therapy configurations. This adjustability optimizes gravity-based flow rates while accommodating varying patient needs and space constraints.
4Area of stationary object
If vertically-oriented dialysate bag mounting structure is used, then device footprint is reduced, but portability becomes challenging
Solution Approach 1:
The patent incorporates locking casters that can be engaged or disengaged as needed. When engaged, they provide stable support for the vertical configuration during therapy delivery, minimizing footprint. When disengaged, they allow the device to be easily moved for cleaning, maintenance, or repositioning, thus resolving the portability challenge.
5Speed
If heavy dialysate bags are lifted to high positions, then gravity-based flow is achieved, but patient safety and comfort deteriorate
Solution Approach 1:
The patent employs a counterbalance mechanism that uses a spring-loaded arm to offset the weight of the dialysate bag. The spring is tensioned to match the bag's weight, creating a balanced system that requires minimal force to lift and position the bag, thereby eliminating safety hazards associated with heavy lifting while maintaining adequate height for gravity-based flow.
6Measurement precision
If load cells are used for fluid measurement, then measurement precision is improved, but reliability deteriorates due to overload damage
Solution Approach 1:
The patent incorporates overload protection mechanisms including mechanical hard stops that prevent excessive deflection of the load cell, and software monitoring that detects and responds to overload conditions. These protective measures are built in beforehand to prevent damage from accidental overloading, ensuring long-term reliability while maintaining measurement precision.
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 cost-effective, comfortable, and efficient dialysis with reduced device footprint, preventing free flow, improving flow rates, and enhancing reliability while being portable and easy to set up and transport.
Implementation Method 1
heats at least one dialysate bag placed onto a heated plate
Implementation Method 2
The drain unit weighs the drain container via one or more load cells
Implementation Method 3
the present system provides an automated peritoneal dialysis (APD) system which uses gravity to deliver fluid from one or more source dialysate bags to the patient as the destination, and uses gravity to deliver fluid from the source patient to the destination drain container
Data Source
AI summary
The present disclosure relates to an automated peritoneal dialysis (APD) system using gravity to deliver fluid from one or more source dialysate bags to the patient as the destination. The present disclosure further relates to a quick release mechanism useful in the assembly and disassembly of components, including a heater unit and a control unit of a peritoneal dialysis system.