Pulsed Radar Level Gauge Pulse Feedback Delay Line
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Solution Overview
Problem
Pulsed radar level gauges face challenges in maintaining reliable and robust level measurements over varying temperature ranges due to changes in pulse shape and component performance, particularly in hazardous environments where explosion-proof and intrinsically safe designs are required.
Innovation Solution
The solution involves a pulsed radar level gauge with impedance matching circuitry and a delay line to ensure detection of the transmitted pulse, allowing for compensation in processing based on environmental factors, and includes a feedback control system for adjustable pulse width to maintain precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the radar level gauge operates in hazardous environments with explosion-proof design, then safety is improved, but the available energy for signal transmission and reception is restricted
Solution Approach 1:
The pulse width is made dynamically adjustable based on temperature conditions. The control circuit modifies the pulse duration from the nominal value depending on the detected temperature, allowing optimization of signal transmission within the restricted energy budget while maintaining measurement accuracy across varying thermal conditions in hazardous environments
Solution Approach 2:
The system changes the pulse width parameter dynamically according to temperature. At different temperatures, the pulse duration is adjusted to compensate for changes in signal propagation characteristics, enabling reliable operation within intrinsically safe energy constraints while adapting to environmental variations
2Device complexity
If the pulse width is fixed at a nominal value, then the device complexity is reduced, but the measurement precision deteriorates under varying temperature conditions
Solution Approach 1:
A temperature sensor provides feedback about the environmental conditions to the control circuit. This feedback loop enables the system to automatically adjust the pulse width based on actual temperature readings, maintaining measurement precision without requiring complex manual calibration or intervention
Solution Approach 2:
The pulse width transitions from a fixed static value to a dynamically adjustable parameter controlled by temperature conditions. This dynamic adaptation allows the system to maintain high measurement precision across varying temperatures while keeping the overall device complexity manageable through automated control
3Reliability
If the pulse width is increased to improve signal detection, then the detection capability is improved, but the time resolution for level measurement deteriorates
Solution Approach 1:
The pulse width is adjusted as a variable parameter based on temperature conditions rather than being fixed. This allows optimization of the pulse duration to achieve sufficient signal detection while maintaining adequate time resolution for accurate level measurement, balancing both requirements dynamically
Solution Approach 2:
The system dynamically adjusts pulse width to balance detection capability and time resolution. By making the pulse duration adaptable rather than fixed, the system can optimize the trade-off between signal strength and measurement precision according to actual operating conditions
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 approach enhances the reliability and robustness of level measurements by accurately accounting for environmental effects on pulse shape and ensuring compliance with intrinsic safety and electromagnetic compatibility requirements.
Implementation Method 1
a frequency generator for generating a Tx frequency signal and a Rx frequency signal
Implementation Method 2
return a microwave return signal resulting from a reflection caused by a surface of the product
Implementation Method 3
a receiver connected to the propagation device and configured to receive the microwave return signal SR reflected from the tank
Implementation Method 4
sampling circuitry connected to the receiver and to the frequency generator, and configured to sample the received signal with a sampling frequency equal to the Rx frequency
Implementation Method 5
a delay line arranged between the receiver and the propagation device, the delay line being configured to introduce a delay greater than the pulse duration
Data Source
AI summary
A pulsed radar level gauge comprising a pulse generator configured to generate a transmit signal (ST) in the form of a pulse train, a propagation device connected to direct the transmit signal (ST) into a tank and return a microwave return signal (SR), a receiver, sampling circuitry configured to provide a time expanded tank signal, and processing circuitry for determining said filling level based on the time expanded tank signal. The gauge further comprises impedance increasing circuitry arranged to ensure that an input impedance of the receiver is at least 2 kΩ and a delay line arranged between said receiver and said propagation device, the delay line configured to introduce a delay greater than said pulse duration, such that said time expanded signal includes a transmitted pulse.