Cryogenic Tank Bottom Pressure Control
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Solution Overview
Problem
Existing tank arrangements for cryogenic media only measure the fill level and do not efficiently manage energy usage, as they lack comprehensive control over the liquid and gaseous phases, leading to suboptimal operation and potential inefficiencies.
Innovation Solution
A tank arrangement with a differential pressure measuring device, absolute pressure measuring device, and temperature sensor, coupled with an evaporator and control unit that regulates gas pressure via a gas pressure control valve, allowing for precise control of the liquid level by maintaining a constant ground pressure, thereby optimizing energy usage and reducing the need for liquid evaporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the gas pressure is regulated using a vent valve to reduce pressure in the upper tank region, then the gas pressure can be reduced, but energy is wasted through continuous venting and the control tolerance increases
Solution Approach 1:
The patent changes the control parameter from direct gas pressure regulation via vent valve to bottom pressure regulation via gas pressure control valve. By regulating the bottom pressure of the liquid portion instead of directly controlling the gas pressure, the system achieves more precise pressure control with smaller control tolerances and reduces energy consumption by minimizing unnecessary venting operations.
Solution Approach 2:
The patent implements a feedback control system where the bottom pressure regulator continuously monitors the bottom pressure and adjusts the gas pressure control valve accordingly. This closed-loop feedback mechanism maintains the bottom pressure within a narrow tolerance range, preventing the need for frequent vent valve operations and reducing energy waste.
2Measurement precision
If the gas pressure control valve is controlled directly via the control unit using absolute pressure and temperature in the upper tank area, then the control tolerance can be reduced, but the gas bubble in the upper tank area must be designed to be smaller
Solution Approach 1:
The patent introduces bottom pressure as an intermediary parameter between the gas pressure control system and the liquid level. Instead of directly controlling gas pressure based on upper tank conditions, the system regulates bottom pressure, which indirectly controls gas pressure while allowing for a larger gas bubble volume and maintaining precise control tolerance.
3Device complexity
If only the fill level is measured without comprehensive control systems, then the device complexity is reduced, but the application potential cannot be fully exploited and energy-saving operation is not achieved
Solution Approach 1:
The patent implements a multi-functional control system where the bottom pressure regulator serves multiple purposes: it controls bottom pressure, regulates gas pressure, optimizes energy consumption, and enables precise fill level measurement. This universal control approach fully exploits the application potential of the tank arrangement while maintaining manageable device complexity.
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 solution enables precise control of the liquid level, reduces energy consumption by minimizing the amount of liquid medium evaporated, and ensures safe and precise filling and emptying of the tank, while maintaining a stable gas pressure in the upper tank area.
Implementation Method 1
an evaporator is provided in an outlet of the tank to increase the gas pressure
Implementation Method 2
a differential pressure measuring device, which is connected via a fluid line to a lower tank region containing the liquid portion of the medium, and via another fluid line to an upper tank region containing the gaseous portion of the medium
Implementation Method 3
an absolute pressure measuring device, and/or a temperature sensor for measuring the pressure and/or temperature in the upper tank region
Implementation Method 4
an absolute pressure measuring device, and/or a temperature sensor for measuring the pressure and/or temperature in the upper tank region
Data Source
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AI summary
Method and tank arrangement for controlling the filling level of cryogenic media, comprising: a tank (6) having an inflow line (10) and an outflow line (12), a differential pressure measuring device (16) which is connected, via a connection line (26), to a lower tank region (28) in which the liquid portion of the medium is present and is also connected, via a further connection line (20), to an upper tank region (22) in which the gaseous portion of the medium is present, an absolute pressure measuring device (18) and/or a temperature sensor (18) for measuring the pressure and/or the temperature in the upper tank region (22), an evaporator (38) in a branch line (36) between the inflow line (10) and the upper tank region (22), a gas pressure control valve (34) which is suitable for controlling the pressure, is downstream of the evaporator (38) in the branch line (36) and is intended to control the pressure in the upper tank region (22), a bottom pressure controller (32) which is connected to the differential pressure measuring device (16) and to the absolute pressure measuring device (18) and/or to a temperature sensor (18) and is intended to control the gas pressure control valve (34), wherein the bottom pressure controller (32) is configured to control the pressure in the gaseous portion of the medium in the tank (6) to a constant bottom pressure on the basis of the filling level of the liquid portion of the medium.