Blood Purification Solution Circuit with Bypass for Thermal Control
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Solution Overview
Problem
Existing blood purification systems face challenges in maintaining solution temperature control, particularly during solution flow stoppage, which can lead to overheating and potential thermal breakdown or hemolysis, due to high thermal inertia in heating elements and external temperature control methods.
Innovation Solution
A solution circuit apparatus with a warmer, temperature sensors, bypass branch, and control unit that recirculates solution through the warmer when flow is stopped, and adjusts pump rate based on temperature sensors to prevent overheating, while ensuring sterile and efficient heat transfer using disposable heated passages and flexible tubing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the heating element has a large heating surface to ensure efficient heat transfer, then the heating efficiency is improved, but the thermal inertia increases leading to potential overheating when solution flow is stopped
Solution Approach 1:
The patent implements dynamic control of the heating element power based on real-time temperature sensor feedback. The control unit adjusts the power supplied to the heating element according to the measured solution temperature, enabling the system to adapt to changing flow conditions and prevent overheating while maintaining efficient heating during normal operation
Solution Approach 2:
The patent incorporates temperature sensors that continuously monitor the solution temperature and provide feedback to the control unit. This feedback mechanism allows the system to detect temperature changes and adjust the heating element power accordingly, preventing overheating when solution flow is stopped while maintaining efficient heating during flow
2Use of energy by moving object
If the heating element surface temperature is maintained higher than desired solution temperature for efficient heat flow, then heat transfer efficiency is improved, but the risk of solution overheating increases when flow is interrupted
Solution Approach 1:
The patent implements preliminary protective action by monitoring solution flow status and preemptively adjusting heating element power before overheating can occur. When solution flow interruption is detected, the control unit reduces or stops heating element power in advance, preventing the dangerous temperature differential from causing overheating while maintaining efficient heat transfer during normal flow
Solution Approach 2:
The temperature sensors provide continuous feedback on solution temperature, enabling the control unit to maintain the heating element surface temperature optimally - high enough for efficient heat transfer during flow, but reduced when flow is interrupted to prevent overheating
3Ease of manufacture
If external temperature sensors are used for cost reasons, then manufacturing cost is reduced, but temperature measurement precision and response time are limited
Solution Approach 1:
The patent uses the disposable conduit as a thermal intermediary between the solution and the external temperature sensor. The conduit conducts heat from the solution to the sensor, enabling cost-effective external temperature measurement while improving measurement accuracy and response time through optimized thermal coupling between the sensor and solution
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
This solution effectively reduces the risk of overheating, maintains solution sterility, and optimizes temperature control, ensuring patient safety by continuously cooling the solution and reducing the risk of thermal damage during blood purification therapies.
Implementation Method 1
there are known teachings for heating the solution by means of a warmer, wherein a heating element is provided to make contact on a surface of the disposable conduit. Thus the solution is heated inline, that is to say it is heated as it passes through the solution circuit, by means of thermal conduction.
Implementation Method 2
Temperature control is provided by temperature sensors placed preferably, for reasons of cost, externally to the disposable conduit, rather than directly in contact with the solution.
Implementation Method 3
In the case of these known warmers the heating element has a high thermal inertia, in particular since it tends to have a large heating surface. Also the temperature of the heating element surface must be higher than the desired solution temperature in order to ensure efficient heat flow. In the case that the solution delivery is stopped by the user or by an alarm signal, for example, there is the possibility of temporary and local overheating of the solution even when power to the warmer is stopped.
Data Source
Figure 1
AI summary
A solution circuit apparatus (30) for a blood purification system (50) comprising an extracorporeal blood circuit (40) and the solution circuit apparatus (30), comprises: a solution source (1); a warmer (3) having a temperature sensor (8); a bypass branch (26); a delivery branch (25) communicating with the extracorporeal blood circuit (40); a pump (2); a switching means (5); and a control unit (39) configured to set the solution circuit apparatus (30) into one of a solution delivery condition and a solution stop condition. In the solution delivery condition the switching means (5) interrupts the bypass branch (26), and the pump (2) delivers solution via the warmer (3) and through the delivery branch (25). In the solution stop condition the switching means (5) interrupts the delivery branch (25), and the pump (2) recirculates solution through the warmer (3) via the bypass branch (26). In the therapy stop condition the pump rate is dependent on the output of the temperature sensor (8).