Two-Stage Tyre Vulcanization Reducing Mould Occupancy
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Solution Overview
Problem
High-performance tyre vulcanization processes require long cycles at middle-range temperatures, leading to increased production costs due to prolonged mould occupancy, and existing two-stage vulcanization methods fail to replicate the performance of single prolonged mould vulcanization.
Innovation Solution
A method and apparatus that complete vulcanization by transferring a semi-vulcanized tyre to a heated chamber where heat is applied to the outer surface and cooling occurs on the inner surface, maintaining temperatures between 130°C and 180°C to achieve optimal cross-linking without over-vulcanization, while reducing mould occupancy time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If long vulcanization cycles are used at middle-range temperatures for high-performance tyres, then the tyre performance and cross-linking quality are improved, but the mould occupancy time increases leading to higher production costs
Solution Approach 1:
The vulcanization process is divided into two distinct stages: a first stage in the mould at middle-range temperatures (140-170°C) for partial cross-linking, and a second stage in a post-vulcanization chamber at higher temperatures for completing the cross-linking. This segmentation allows the mould to be freed earlier while the tyre finishes vulcanization outside, reducing mould occupancy time and production costs while maintaining tyre performance
Solution Approach 2:
A post-vulcanization chamber serves as an intermediary device that takes over the vulcanization process from the mould. This intermediary chamber equips with heating and cooling systems to complete the vulcanization process, allowing the mould to be reused while the tyre achieves full cross-linking in the intermediate facility
2Productivity
If the tyre is removed from the mould before complete vulcanization, then the mould occupancy time is reduced, but the vulcanization quality may be compromised
Solution Approach 1:
The first vulcanization stage in the mould performs preliminary cross-linking to a controlled extent (partial vulcanization), preparing the tyre for completion outside the mould. This preliminary action ensures the tyre has sufficient structural integrity to be removed while still achieving full vulcanization quality in the second stage
Solution Approach 2:
The vulcanization parameters are changed between stages: the first stage uses middle-range temperatures (140-170°C) for partial cross-linking, while the second stage uses higher temperatures in the post-vulcanization chamber to complete the cross-linking process, ensuring full vulcanization quality is achieved despite the two-stage approach
3Productivity
If existing two-stage vulcanization methods are used, then the mould occupancy time is reduced, but the performance characteristics are not replicated compared to single prolonged mould vulcanization
Solution Approach 1:
The post-vulcanization chamber is equipped with controllable heating and cooling systems that replicate and extend the thermal profile of prolonged mould vulcanization. By carefully controlling temperature parameters in the second stage, the method achieves the same cross-linking quality and performance characteristics as single-stage prolonged vulcanization while reducing mould occupancy time
Solution Approach 2:
The post-vulcanization chamber acts as an intermediary that extends the vulcanization environment beyond the mould. This intermediary facility maintains and controls the thermal conditions necessary to achieve full vulcanization quality, ensuring performance characteristics match those of single prolonged mould vulcanization while enabling mould reuse
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 approach allows for efficient completion of vulcanization outside the mould, maintaining performance characteristics similar to single mould vulcanization, thereby reducing production costs and increasing plant efficiency by freeing up moulds for new tyres.
Implementation Method 1
heat is applied to the outer surface
Implementation Method 2
cooling occurs on the inner surface
Data Source
Figure 1
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AI summary
A method of vulcanizing a green tyre having a toroidal structure is described, the method comprising: introducing a green tyre into a vulcanization mould; partially vulcanizing the green tyre so as to produce a semi-vulcanized tyre; removing the semi-vulcanized tyre (60) from said vulcanization mould; completing the vulcanization of the semi-vulcanized tyre outside said vulcanization mould. Moreover, the vulcanization completion action comprises: bringing at least one portion of said semi-vulcanized tyre to a temperature having a value of between about 75% and about 120% of the temperature of said at least one portion of semi-vulcanized tyre at the moment of its removal from the vulcanization mould, within a period of time of between about 2 minutes and about 7 minutes from the time at which said semi-vulcanized tyre was removed from said mould. The invention also relates to an apparatus for completing the vulcanization (3) of a semi-vulcanized tyre and to a vulcanization plant.