External Temperature Sensor Signal Correction for Wall Heat Transfer
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Solution Overview
Problem
Measuring the temperature of a medium in a container or pipe is imprecise when the sensor is placed outside due to the wall's heat transfer characteristics, leading to delayed and inaccurate readings, especially for aggressive or high-pressure media.
Innovation Solution
A measuring device with a temperature sensor on the outside of the container or pipe, equipped with a differentiator, multiplier, and adder circuit to correct for the time constant of heat transfer through the wall, and optionally a second-order correction for the temperature sensor's heat capacity, along with a correction apparatus for ambient temperature influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the temperature sensor is arranged on the outside of the wall to measure aggressive or high-pressure media, then the safety and accessibility are improved, but the measurement precision deteriorates due to heat transfer limitations through the wall
Solution Approach 1:
The patent introduces an intermediary evaluation unit that acts as a mediator between the temperature sensor and the measurement output. This evaluation unit includes a differentiator, multiplier, and adder that process the sensor signal to compensate for the wall's heat transfer characteristics, effectively bridging the gap between the sensor's limited capabilities and the requirement for precise measurement.
Solution Approach 2:
The patent changes the parameters of the measurement system by introducing dynamic correction factors (time constant F1 and sensor heat capacity F2) that adjust the sensor reading in real-time. These parameter changes allow the system to compensate for the thermal inertia and heat transfer delays introduced by the wall, thereby improving measurement precision while maintaining sensor safety.
2Strength
If the wall thickness is increased to protect against aggressive media, then the sensor protection is improved, but the heat transfer through the wall deteriorates leading to imprecise measurements
Solution Approach 1:
The patent implements feedback mechanisms through the evaluation unit that continuously monitors and corrects the temperature reading based on the wall's thermal characteristics. The differentiator and multiplier components process the sensor signal with feedback correction factors that account for the increased wall thickness, allowing accurate measurement despite the protective barrier.
3Measurement precision
If a temperature sensor is placed inside the container or pipe to achieve accurate measurements, then the measurement precision is improved, but the sensor reliability deteriorates due to exposure to aggressive or high-pressure media
Solution Approach 1:
The evaluation unit serves as an intermediary that allows the temperature sensor to remain outside the aggressive environment while still achieving accurate measurements. The differentiator, multiplier, and adder components process the sensor signal to compensate for the thermal barrier, effectively enabling precise measurement without direct sensor exposure to harmful media.
4Speed
If the temperature sensor responds quickly to temperature changes, then the response speed is improved, but the measurement precision deteriorates due to thermal inertia of the wall and sensor
Solution Approach 1:
The patent applies parameter changes by introducing correction factors (F1 for wall heat transfer time constant and F2 for sensor heat capacity) that dynamically adjust the sensor reading. These parameter modifications allow the system to account for thermal inertia effects, thereby improving measurement precision while maintaining rapid response capability through the differentiator and multiplier processing.
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
Significantly improves the precision of temperature measurements by correcting for the time delay and heat transfer characteristics, allowing for accurate representation of temperature changes, even in aggressive or high-pressure environments.
Implementation Method 1
a first differentiator, capable of determining at least one first derivative of a progression over time of the temperature (TF), registered by the temperature sensor
Implementation Method 2
a first multiplier configured to multiply the first derivative by a first factor (F1), the first factor (F1) being a value for a time constant of heat transfer through the wall
Implementation Method 3
an adder, wherein the first differentiator, the first multiplier, and the adder are connected between the temperature sensor output and the measuring device output
Data Source
AI summary
A measuring device for determining the temperature of a medium in a container or a pipe has at least one temperature sensor, arranged on the outside of a container or pipe wall; an output for the temperature registered thereby; and an output for the measurement result obtained thereby. The device connects at least one first differentiator, capable of determining at least one first derivative of the progression over time of the temperature registered by the temperature sensor; at least one first multiplier for multiplying the derivative by a first factor which is a value for the time constant of the heat transfer through the wall; andat least one adder,between the output of the temperature sensor and the output of the measuring device.