Multiply Secured Oxygen Lance Coupling for Leak Prevention
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Solution Overview
Problem
Existing coupling devices for oxygen lances and safety pipes in steelworks often fail to prevent leaks of highly flammable gases, especially when the connection is not tightened properly, posing a safety risk due to incomplete sealing.
Innovation Solution
A multi-secured coupling device design featuring a safety tube with a plug-in part and a union nut, extended by a safety piece, equipped with a ring seal and an additional sealing surface, which ensures sealing even when the union nut is loosely seated, creating multiple sealing zones to prevent gas escape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple thread coupling is used between the safety tube and lance holder, then the device complexity is reduced and ease of manufacture is improved, but the sealing reliability deteriorates when the coupling is not tightly fastened
Solution Approach 1:
The coupling device is segmented into multiple sealing zones: a first sealing zone with an O-ring seal at the front end of the safety tube, and a second sealing zone with a seal at the rear end. This segmentation ensures that even if one sealing zone is compromised due to loose fastening, the other zone maintains the seal, thereby improving reliability without requiring complex additional mechanisms.
Solution Approach 2:
The safety tube is pre-configured with sealing elements (O-rings and seals) at both ends before assembly. The extended front end and rear end seals are preliminarily positioned to create multiple sealing zones that automatically engage upon insertion, ensuring sealing reliability is built-in before the coupling is fastened, eliminating the need for complex post-assembly sealing mechanisms.
2Reliability
If the coupling device is designed with extended safety piece and multiple sealing zones, then the sealing reliability is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The extended front end of the safety tube serves multiple functions: it extends the first sealing zone deeper into the lance holder for enhanced sealing, provides structural support for the coupling connection, and creates a mechanical interlock feature. This multi-functionality reduces the need for separate components, thereby improving reliability while maintaining manufacturing simplicity.
Solution Approach 2:
The coupling device employs a nested structure where the safety tube with extended ends is inserted into the lance holder, and the union nut fastens over these extended portions. The sealing elements are nested within grooves on the safety tube, creating a compact design that achieves multiple sealing zones without significantly increasing manufacturing complexity or component count.
3Reliability
If the union nut is loosely fastened due to careless operation, then the ease of operation is improved, but the sealing reliability deteriorates and gas leakage occurs
Solution Approach 1:
The coupling device incorporates a mechanical interlock feature through the extended front end of the safety tube that engages with the lance holder before the union nut is fully fastened. This preliminary mechanical engagement acts as a cushion, preventing complete disengagement even if the union nut is loosely fastened, thereby maintaining sealing reliability while allowing easy operation and disassembly when properly fastened.
Solution Approach 2:
The sealing pressure parameter is distributed across multiple sealing zones rather than concentrated at a single point. The extended front end and rear end seals create a gradient of sealing pressure, ensuring that even with reduced fastening torque due to careless operation, sufficient sealing pressure is maintained at both sealing zones to prevent gas leakage, thus improving reliability without affecting operational ease.
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 design effectively prevents leaks and ensures tightness, even if the union nut is not fully tightened, providing enhanced safety by creating multiple sealing zones that maintain the seal and prevent the escape of highly flammable gases, such as oxygen, during the injection into molten steel.
Implementation Method 1
equipped with at least one ring seal which seals against the connecting part of the lance holder in the area of sealing surfaces
Implementation Method 2
an additional sealing surface is created in the extended area of the plug-in part or in the area of the safety piece, which makes it even more difficult or impossible for highly flammable gas to escape
Data Source
Figure 1~2
Figure 3~5
Figure 6
AI summary
A multiply secured coupling device for oxygen lances (1) is achieved in that both the plug-in part (8) of the safety pipe (3) and the connection part (18) of the lance holder (2) and also the union nut (9) have an extending safety piece (10, 11). As a result, the plug-in part (8) can be pushed a considerable distance into the nut part (19) or into the connection part (18) and then be fixed via the union nut (9). A total of five sealing zones, which in particular together effectively prevent the escape of highly flammable gases, in particular oxygen, are produced.