Gravity-Based APD Layout for Low-Pressure Fluid Delivery
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Solution Overview
Problem
Existing automated peritoneal dialysis (APD) devices are costly, 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 cell measurements, among other challenges.
Innovation Solution
A gravity-based APD system using solenoid-operated pinch valves, modular enclosures with toolless assembly, reusable drain containers, and protected load cells to ensure safe, efficient, and portable dialysis with improved flow rates and reduced environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active pumping APD devices are used, then fluid delivery and drainage can be controlled, but the device cost and disposable tubing set cost increase significantly
Solution Approach 1:
The patent removes the active pump, valves, and control mechanisms from the APD device, extracting these expensive components entirely. Instead, the system uses gravity-based flow control where dialysate bags are positioned at different heights to control fluid delivery and drainage passively, eliminating the need for costly pumping and valve systems while maintaining reliable fluid management
Solution Approach 2:
The system enables self-service fluid management through gravity-based flow control. The dialysate bags are positioned at different heights (heater bag on the device, supply bag and last fill bag on a shelf above) to automatically control fluid delivery and drainage without active pumps or valves, reducing device complexity and cost while maintaining functional reliability
2Productivity
If active pumping APD devices are used, then fluid flow can be maintained, but excessive delivery and suction pressures cause patient discomfort
Solution Approach 1:
The patent replaces the mechanical pump-based fluid delivery system with a gravity-based system. By positioning dialysate bags at different heights, the system uses gravitational force to control fluid flow rates, eliminating excessive delivery and suction pressures that cause patient discomfort while maintaining adequate fluid exchange
Solution Approach 2:
The system changes the flow control parameter from active pump pressure to passive gravitational head pressure. By adjusting the vertical position of dialysate bags relative to the patient's abdomen, the system optimizes flow rates using gravity, avoiding the high pressures generated by active pumps that lead to patient discomfort during inflow and outflow phases
3Reliability
If active pumping APD devices with cassettes are used, then fluid control is precise, but the disposable tubing set cost increases
Solution Approach 1:
The patent removes the expensive cassette component from the disposable tubing set. Instead of using cassettes with integrated membranes and bonding structures, the system uses a simplified tubing set that connects directly to the gravity-based fluid management system, eliminating the need for costly ultrasonic welding and reducing material costs
Solution Approach 2:
The system adopts a disposable tubing set design that uses simpler, cheaper materials and construction methods. By eliminating the cassette and its associated bonding requirements, the disposable tubing set can be manufactured more economically while still providing reliable fluid control through the gravity-based system
4Ease of operation
If gravity-based APD device is made portable with vertical orientation, then mobility is improved, but the device height increases making it difficult to position
Solution Approach 1:
The patent transitions from a horizontal layout to a vertical arrangement of components. The dialysate bags are positioned vertically at different heights (heater bag on the device, supply and last fill bags on a shelf above), enabling gravity-based flow control in a compact footprint that improves mobility while managing the height challenge through strategic vertical positioning
5Measurement precision
If load cells are used to measure fluid volume, then measurement accuracy is achieved, but the load cells are vulnerable to overload damage
Solution Approach 1:
The patent implements protective mechanisms for load cells before overload can occur. By positioning the heater bag and supply bags at controlled heights and using gravity-based flow control, the system prevents excessive forces from being applied to the load cells, cushioning them against overload damage while maintaining measurement accuracy
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, portable, and user-friendly APD therapy with minimized patient discomfort, reduced therapy duration, and enhanced reliability by preventing free fluid flow and load cell overload, while maintaining accurate fluid measurement.
Implementation Method 1
solenoid-operated pinch valves
Implementation Method 2
uses gravity to deliver fluid from one or more source dialysate bags to the patient as the destination, and using gravity to deliver fluid from the source patient to the destination drain container
Implementation Method 3
heats at least one dialysate bag placed onto a heated plate
Implementation Method 4
The drain container is positioned on a drain unit that includes a load cell. The load cell is protected from overload conditions in the up and down directions. The heater bag is positioned on a heater unit that includes another load cell
Implementation Method 5
one or more solenoid-operated, normally closed, electronically-controlled pinch valves which pinch or release the disposable tubing set's tubing to stop or start fluid flow
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 drain container arrangement for receiving and storing spent dialysis effluent from a patient, wherein the drain containers include self-opening valves activated when the containers are arranged together, and the valves are self-sealing when the containers are disconnected from one another.