LNG Dispenser Density Measurement via Capacitance and Temperature Probes
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Solution Overview
Problem
Existing LNG dispensers face challenges such as the need for cooling prior to dispensing, high costs due to the use of Coriolis-type flow meters, and bulkiness resulting from housing both density and volumetric flow-measuring devices within the same chamber, which affects accuracy and efficiency.
Innovation Solution
A dispenser system with a separated density-measuring device and flow-measuring device configuration, utilizing a capacitance probe and temperature probe to calculate LNG density and volumetric flow rate, and a control system to manage the dispensing process, including a chill-down conduit for initial cooling and vapor flushing, allowing for accurate and efficient LNG dispensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Coriolis-type flow meter is used for mass flow measurement, then measurement accuracy is improved, but device cost increases
Solution Approach 1:
The patent divides the measurement system into separate functional components: a density-measuring device (using capacitance and temperature probes) and a volumetric flow-measuring device. This segmentation allows each component to be optimized independently and reduces overall system cost compared to using a single expensive Coriolis flow meter for both functions.
Solution Approach 2:
The patent combines multiple measurement functions (density measurement via capacitance probe, temperature measurement via temperature probe, and volumetric flow measurement) into a unified dispensing system. By integrating these separate measurement capabilities, the system achieves mass flow measurement accuracy comparable to Coriolis meters while avoiding their high cost.
2Device complexity
If both density-measuring device and volumetric flow-measuring device are housed within the same chamber, then integration is improved, but dispenser bulkiness increases
Solution Approach 1:
The patent transitions from a single-chamber three-dimensional integration to a multi-chamber distributed arrangement. The density-measuring device is positioned in the liquid flow path while the volumetric flow-measuring device is positioned in the vapor space, utilizing different spatial dimensions and phases to achieve functional integration without increasing overall dispenser volume.
Solution Approach 2:
The dispensing chamber serves as an intermediary space that connects the liquid phase (where density measurement occurs) and the vapor phase (where volumetric flow measurement occurs). This intermediary chamber allows both measurement devices to function simultaneously without direct physical overlap, reducing bulkiness while maintaining integration.
3Measurement precision
If the dispenser is cooled to LNG temperature prior to dispensing, then measurement accuracy is improved, but dispensing time increases
Solution Approach 1:
The patent performs preliminary cooling of the dispenser to LNG temperature before the actual dispensing and measurement process. By completing the cooling action in advance, the system ensures accurate temperature and dielectric constant measurements during dispensing without delaying the productive dispensing operation itself.
Solution Approach 2:
The patent maintains continuous monitoring of temperature and dielectric constant during the dispensing process, allowing for real-time calculation of density and mass flow rate. This continuous measurement approach ensures accuracy throughout the dispensing operation without requiring repeated cooling cycles.
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 provides accurate mass flow measurement of LNG, reduces the bulkiness and cost of the dispenser, and ensures compliance with certification standards by improving temperature and dielectric constant measurement accuracy, enabling precise and efficient LNG dispensing.
Implementation Method 1
a capacitance probe may measure the dielectric constant
Implementation Method 2
a temperature probe may measure the temperature
Implementation Method 3
The measured dielectric constant and temperature may then by utilized to calculate the density of LNG flowing through the dispenser by known principles
Implementation Method 4
A volumetric flow rate of the LNG may then be determined by, for example, a volumetric flow meter associated with the dispensing chamber
Implementation Method 5
The acquired density and volumetric flow rate may be used to compute the mass flow rate of the dispensed LNG
Data Source
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AI summary
Embodiments of the disclosure may include a dispenser for dispensing a liquid. The dispenser may include a measurement chamber configured to receive the liquid, a temperature probe positioned within the measurement chamber, and a capacitance probe positioned within the measurement chamber. The capacitance probe may house the temperature probe. The dispenser may also include a first conduit fluidly coupled to the measurement chamber and configured to deliver the liquid out of the dispenser.