Fluid Tank Vacuum Pumping for Stable Insulation and Lower Boil-Off
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Solution Overview
Problem
Existing fluid tanks for liquefied gases face challenges in maintaining an effective insulation vacuum, leading to increased heat input and boil-off due to deterioration over time, especially in mobile applications.
Innovation Solution
Equipping fluid tanks with a dedicated vacuum pump and a connection for active vacuum maintenance, allowing for continuous or intermittent pumping to preserve the insulation vacuum, and providing a separate connection for external vacuum pumps for compatibility and refueling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive thermal insulation measures are used, then the initial insulation performance is good, but the insulation vacuum deteriorates over time leading to increased heat input
Solution Approach 1:
The patent transitions from passive static insulation to active dynamic insulation by introducing a vacuum pump system that continuously or periodically restores the vacuum level. The system includes a vacuum pump (23) connected to the insulation space (21) through a connection (25), controlled by a control unit that monitors vacuum quality and activates pumping when deterioration is detected, making the insulation system adaptive and self-correcting over time.
Solution Approach 2:
The patent implements a feedback control mechanism where the deterioration of the insulation vacuum is detected (through pressure sensors or boil-off rate monitoring) and this information triggers the activation of the vacuum pump system. The control unit receives signals about the vacuum quality and automatically initiates pumping operations to restore the vacuum, creating a closed-loop system that maintains insulation performance despite time-related deterioration.
2Reliability
If a dedicated vacuum pump is installed on the fluid tank, then the insulation vacuum can be actively maintained, but the device complexity increases
Solution Approach 1:
The vacuum pump system is designed with multi-functionality to justify the added complexity. The same vacuum pump connection infrastructure serves both the insulation vacuum maintenance function and the fuel filling function. The connection (25) on the housing (19) can be used for vacuum pumping during operation and for refueling the inner container, reducing the need for separate dedicated connections and components.
Solution Approach 2:
The system is designed to be self-servicing where the vehicle's existing vacuum pump (when equipped) or external vacuum pumps at service stations can be used to maintain the insulation vacuum. The control unit automatically manages the pumping operations based on monitored vacuum quality, eliminating the need for manual intervention or complex manual vacuum restoration procedures.
3Ease of manufacture
If the vacuum pump connection is integrated during manufacture, then the initial evacuation is efficient, but external vacuum pumping devices are incompatible
Solution Approach 1:
The connection (25) on the housing (19) is designed as a universal interface that serves multiple purposes: it enables the vacuum pump to evacuate the insulation space during manufacturing, allows external vacuum pumps at service stations to restore vacuum later, and can potentially serve fuel filling functions. This multi-functional connection design ensures compatibility across different manufacturing standards and service station equipment.
Solution Approach 2:
The connection infrastructure is pre-installed on the housing during manufacturing, preparing the system for future vacuum restoration operations. By having the connection (25) and vacuum pump (23) ready in advance, the system can quickly restore vacuum conditions at service stations without requiring complex adaptation or special equipment, enabling seamless integration with external vacuum pumping services.
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
Maintains insulation vacuum effectively, reducing heat input and boil-off, enhancing the efficiency of fluid storage by actively managing vacuum conditions.
Implementation Method 1
a volume is present between the inner container and the housing in which an insulating vacuum can be created
Implementation Method 2
The vacuum in the volume between the container and a surrounding casing reduces heat transfer by convection
Implementation Method 3
Heat transfer by thermal radiation can be minimized by additional measures, for example, by wrapping the container with a thermal insulation material
Data Source
Figure 1~2
AI summary
The invention relates to a fluid tank for vehicles, comprising an inner container for a fluid, in particular liquefied gas, and a housing surrounding the inner container, wherein a volume is provided between the inner container and the housing in which an insulating vacuum can be produced, in particular a high vacuum with a pressure in the range of 10-3 to 10-8 mbar or a fine vacuum in the range of 1 to 10-3 mbar, and wherein, in order to maintain a produced insulating vacuum, the fluid tank is provided with at least one of its own vacuum pumps installed on the fluid tank, in particular a turbomolecular vacuum pump, and a connection for the vacuum pump and/or has a connection for an external vacuum pump device.