Cool Drying Heat Exchanger Control Using Internal LAT Sensing
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Solution Overview
Problem
Existing cool drying devices face challenges in accurately measuring the lowest gas temperature (LAT) within the heat exchanger, leading to potential freezing issues and inefficient control valve operation due to delayed temperature measurements and reliance on costly flow sensors.
Innovation Solution
A device with a measuring element positioned inside the secondary part of the heat exchanger to directly measure the LAT or dew point, combined with a control unit that uses coolant temperature to determine load conditions, allowing for timely and accurate control valve operation without a flow sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measuring elements are positioned on the outside of the heat exchanger to measure the lowest gas temperature, then the device structure is simpler, but the measurement precision is insufficient and time delay occurs
Solution Approach 1:
The measuring element is nested inside the secondary part of the heat exchanger, positioned within the gas flow path to directly measure the lowest gas temperature. This internal positioning eliminates measurement delays and improves precision while the measuring element remains integrated within the existing heat exchanger structure.
Solution Approach 2:
The measuring element acts as an intermediary positioned at the critical location where the lowest gas temperature occurs within the heat exchanger. By placing the sensor inside the secondary part, it directly interfaces with the gas flow to capture accurate temperature data without external measurement delays.
2Reliability
If the control valve is controlled based on delayed temperature measurements, then the control system is simpler, but the reliability of preventing freezing is reduced
Solution Approach 1:
The measuring element is positioned to detect the lowest gas temperature in advance before freezing conditions develop. By having the sensor located inside the heat exchanger where the coldest gas occurs, the control system receives early warning signals and can activate the control valve proactively to prevent freezing rather than reacting after the fact.
Solution Approach 2:
The control system uses real-time feedback from the measuring element positioned inside the heat exchanger to continuously monitor the lowest gas temperature. This immediate feedback loop allows the control valve to be adjusted promptly in response to temperature changes, ensuring reliable freezing prevention without time delays.
3Measurement precision
If a flow sensor is used to determine load conditions, then the control accuracy is improved, but the device complexity and cost increase
Solution Approach 1:
The control unit utilizes existing temperature measurements from the measuring element to infer load conditions without requiring a separate flow sensor. By analyzing the relationship between temperature readings and known operating characteristics, the system self-determines load conditions using data already being collected for temperature control.
Solution Approach 2:
The measuring element serves multiple functions: it not only measures the lowest gas temperature for freezing prevention but also provides data that enables the control unit to determine load conditions. This multi-functionality eliminates the need for a separate flow sensor while maintaining control 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
Enables precise and timely control of the cooling process, preventing freezing and adjusting to varying loads without the need for a flow sensor, thus reducing costs and device failures.
Implementation Method 1
cool the gas to be dried and to condense water vapour out of the gas
Implementation Method 2
cooling circuit which is filled with a coolant... whose primary part is the evaporator of a cooling circuit and the gas to be dried flows through the secondary part thereof
Data Source
AI summary
Device for cool drying gas includes a heat exchanger whose primary part is the evaporator of a cooling circuit. The gas to be dried is guided through the secondary part of the heat exchanger to cool the gas and to condense water vapor out of the gas. At least one bypass pipe is provided with a control valve which is controlled by a control unit as a function of signals received from a measuring element for measuring the lowest gas temperature (LAT) or the dew point of the gas in the secondary part of the heat exchanger. The measuring element is positioned directly inside the secondary part of the heat exchanger. Also provided is a measuring element for measuring the temperature of the coolant in the evaporator.