Cryogenic Fluid Transfer Mass Measurement Using Pressure-Derived Density
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Solution Overview
Problem
Current flowmeters for cryogenic fluids, such as liquid hydrogen, either provide inaccurate volume flow rates or are expensive and difficult to implement in vacuum chambers, and mass flowmeters are prone to errors due to bubble interference.
Innovation Solution
A method and device that utilize a pressure difference to transfer cryogenic fluid, involving pressurization, measurement of volume flow rate, and correction of density using pre-pressurization pressure to calculate mass, employing a volumetric flowmeter and pressure sensor to determine fluid density via a formula or table.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If turbine type flowmeters are used to measure liquid hydrogen flow rate, then volume flow rate can be measured, but the measurement is inaccurate for mass-based invoicing and does not account for density variations
Solution Approach 1:
The patent applies parameter changes by measuring the density of the liquid hydrogen at different pressure points (inlet and outlet of the flowmeter) and using these density values to correct the volume flow rate measurement. This allows conversion of volume flow rate to accurate mass flow rate, resolving the contradiction between simple volume measurement and accurate mass measurement.
2Reliability
If Coriolis mass flowmeters are used to measure mass flow rate, then accurate mass flow rate can be obtained, but the device is more expensive and difficult to install in vacuum chambers
Solution Approach 1:
The patent uses an intermediary approach by introducing a density measurement system as a mediator between the volume flow rate measurement and the mass flow rate calculation. Instead of using a complex Coriolis mass flowmeter, the system measures volume flow rate with a simpler flowmeter and then calculates mass flow rate by multiplying by the measured density, thereby avoiding the need for complex Coriolis instrumentation in the vacuum chamber.
3Reliability
If Coriolis mass flowmeters are used, then mass flow rate can be measured, but the reading is disturbed by the presence of bubbles in the liquid
Solution Approach 1:
The patent extracts the harmful bubble interference issue by measuring density at points where the liquid is most stable (inlet and outlet of the flowmeter, away from the bubble-prone measurement zone) and using these density values to correct the flow rate measurement. This separates the density measurement function from the bubble-affected flow measurement function, eliminating bubble interference from the mass flow rate calculation.
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
Accurately determines the mass of transferred cryogenic fluid by correcting volume flow rate measurements with density calculations, ensuring precise invoicing despite pressure changes during transfer.
Implementation Method 1
a pressure sensor for the fluid in the tank
Implementation Method 2
the step of measuring the volume flow rate of withdrawn fluid is realized with a flowmeter of the volumetric type
Implementation Method 3
a system for pressurizing the fluid contained in the tank
Implementation Method 4
a temperature sensor
Data Source
AI summary
The invention relates to a method and a device for transferring liquefied cryogenic fluid, for example liquid hydrogen, from a cryogenic tank containing liquefied cryogenic fluid having a gas phase in equilibrium with the liquid phase, the transfer of fluid to a receiver being realized at least in part by way of a pressure difference between the cryogenic tank and the fluid receiver, the method comprising a step of pressurizing the fluid contained in the cryogenic tank, a step of withdrawing liquid from the pressurized cryogenic tank, a step of measuring the volume flow rate of withdrawn fluid, a step of determining the mass of withdrawn liquid from the measured volume flow rate of withdrawn fluid and the density of the withdrawn fluid, the density of the withdrawn fluid being determined from the pressure of the fluid in the cryogenic tank measured before the pressurization step.