Cryogenic Pipe Connection Sealing With Pressure Equalization
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Solution Overview
Problem
Existing pipe connection devices for low-temperature liquids, particularly cryogenic gases, face significant risk of seal damage due to volume expansion when heated from extreme cold to ambient temperature, leading to potential leakage and costly seal replacement.
Innovation Solution
Incorporation of a pressure equalization channel with a check valve between the secondary seal chamber and the interior space, allowing gas to escape or be discharged back into the interior, preventing damage to the primary seal by expanding gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid gas penetrates into the chamber during operation, then the secondary seal can contain it, but upon heating to ambient temperature the gas expands by a factor of 600 causing damage to the primary seal
Solution Approach 1:
A pressure equalization channel is introduced as an intermediary pathway between the chamber and the interior space. This channel allows gas to escape or be discharged back into the interior, preventing damage to the primary seal by expanding gas during heating from -164°C to room temperature
Solution Approach 2:
The harmful expanding gas is extracted from the chamber through the pressure equalization channel before it can damage the primary seal. The check valve enables selective removal of gas while maintaining the sealing function during operation
2Quantity of substance
If seals are made large in diameter (e.g., more than 400 mm) to handle larger pipes, then more liquid gas can be contained, but the risk of seal damage from expanding gas increases significantly
Solution Approach 1:
The pressure equalization channel with check valve serves as a safety intermediary that allows expanding gas to escape from the chamber, preventing catastrophic seal damage regardless of seal size. This enables the use of larger seals for higher capacity applications without proportionally increasing damage risk
3Reliability
If seals are replaced after damage, then the device can continue operating, but the replacement requires great effort and downtime
Solution Approach 1:
The pressure equalization channel with check valve provides beforehand protection against seal damage by allowing expanding gas to escape before it can cause damage. This preventive measure eliminates the need for difficult seal replacements by preventing the damage condition from occurring
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
Significantly reduces the risk of seal damage and facilitates easy gas escape, maintaining the integrity of the primary seal and simplifying maintenance by ensuring gas remains in a liquid state during expansion.
Implementation Method 1
pressure equalization takes place between the chamber and the interior. For this purpose, it is preferred that the chamber is directly connected to the interior, in particular
Implementation Method 2
Heating liquid gas, for example LMG, from -164° C to room temperature causes the volume to increase by a factor of 600
Data Source
Figure 1~2
AI summary
A pipe connection for joining pipes for transporting low-temperature liquids has two connecting elements (10, 12) for connecting to each pipe end. Each connecting element (10, 12) is connected to a bearing element (16, 18). Furthermore, an inner part (26) is provided which, together with the two connecting elements (10, 12), forms an interior space (26). In addition to an inwardly open groove (28) in which a primary seal (30) is arranged, a circumferential, self-contained chamber (32) is provided in which a secondary seal (34) is arranged. To prevent damage to the secondary seal, particularly during the expansion of liquid gas that has entered the chamber (32), the chamber (32) is connected to the interior space (26) via a connecting channel (36). A check valve (38) is preferably arranged in the connecting channel (36).