Thermal Pad Temperature Control Circuit

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Solution Overview

Problem

Current thermal pad systems fail to maintain a patient's body temperature effectively during medical procedures, as they often overheat or fail to adjust temperature dynamically, especially when dealing with patients of varying mass, and lack integration with IV fluid heating and room temperature sources.

Innovation Solution

A thermal pad system with a heating element, power unit, surface temperature sensors, and a temperature control circuit board that regulates the heating element's power based on sensor data to maintain a safe surface temperature, preventing overheating and ensuring temperature stability across multiple heat sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the heating element is powered to maintain patient temperature, then the patient's body temperature is improved, but the surface temperature of the thermal pad may exceed safe temperature limits

Engineering Contradiction:
Improvepatient body temperatureVSAvoidexcessive surface temperature
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent implements feedback control by continuously monitoring the surface temperature of the thermal pad via temperature sensors and adjusting the heating element power accordingly. The control circuit receives temperature signals and modulates the heating power to maintain surface temperature within safe limits while ensuring adequate heat transfer to the patient.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the heating element power output in real-time based on changing patient conditions and thermal pad temperature. The control circuit continuously modifies power delivery to adapt to varying patient mass, body composition, and thermal requirements, preventing static overheating issues.

Inventive Principle:
Principle #15Dynamics

2Temperature

If the heating element is powered to warm the patient, then the patient temperature is improved, but the system cannot respond appropriately to temperature changes throughout the procedure

Engineering Contradiction:
Improvepatient body temperatureVSAvoidresponse to temperature changes
Core Design Contradiction:
TemperatureVSAdaptability or versatility

Solution Approach 1:

The control circuit continuously monitors temperature and dynamically adjusts heating element power output in real-time. The system adapts to changing patient conditions, surgical environment, and thermal requirements throughout the procedure, providing flexible temperature management rather than static heating.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses continuous temperature feedback from sensors to automatically adjust heating power. This closed-loop control enables the system to respond appropriately to temperature changes during the procedure without manual intervention, maintaining optimal patient temperature throughout.

Inventive Principle:
Principle #23Feedback

3Temperature

If a blanket is used to keep warmth in the patient, then the patient temperature is improved, but the temperature cannot be controlled to the right level

Engineering Contradiction:
Improvepatient body temperatureVSAvoidtemperature control
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The thermal pad system incorporates temperature sensors and control circuits that continuously monitor and adjust heating power based on real-time temperature feedback. This automated feedback control provides precise temperature management, eliminating the need for manual blanket adjustment and achieving accurate temperature control.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces manual mechanical temperature control (blankets) with an automated electronic control system. The control circuit uses electronic sensors and power regulation to automatically maintain target temperature, providing more precise and easier-to-operate temperature management compared to manual blanket methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Temperature

If heated air is used to warm the patient, then the patient temperature is improved, but the heat transfer efficiency and safety are worsened

Engineering Contradiction:
Improvepatient body temperatureVSAvoidheat transfer safety
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The thermal pad acts as an intermediary between the heat source and the patient's body. The pad's heating element provides controlled, direct thermal contact with the patient, improving heat transfer efficiency and safety compared to indirect heated air methods. The pad surface temperature is carefully controlled to ensure safe and effective heat transfer.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 effectively maintains a patient's body temperature within a safe range, preventing overheating and dynamically adjusting to changes in patient mass, while integrating with IV fluid heating and room temperature sources for comprehensive temperature management.

Implementation Method 1

a heating element to heat a surface of the thermal pad

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

a temperature control circuit board embedded within the thermal pad and electrically coupled to the plurality of sensors and the heating element sensor, the temperature control circuit board operable to maintain a temperature at the surface of the thermal pad to a safe temperature based on the temperature detected by the plurality of sensors and the heating element sensor

Methodology Applied
Scientific EffectFeedback control: Feedback

Implementation Method 3

The patient's body would heat the surface temperature of the thermal pad above a selected safe temperature

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2123118B1Device and method for temperature management of heating pad systems
Publication Date: 2013.12.25 MEDLINE INDUSTRIES
  • EP2123118B1 patent drawingFigure 1
  • EP2123118B1 patent drawingFigure 2A
  • EP2123118B1 patent drawingFigure 2B~2C

AI summary

According to some embodiments, an apparatus for warming a patient on a thermal pad includes a heating element to heat a surface of the thermal pad. A power unit is operable to provide power to the heating element. Respective ones of a plurality of sensors are coupled to detect temperature at select portions of the surface of the thermal pad, while a heating element sensor is coupled to detect a temperature of the heating element. A temperature control circuit board is embedded within the thermal pad and is electrically coupled to the plurality of sensors and the heating element sensor. The temperature control circuit board is operable to limit a temperature at the surface of the thermal pad to a safe temperature based on the temperature detected by the plurality of sensors and the heating element sensor.