Press Apparatus Outer Convection Loop Cooling
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Solution Overview
Problem
High-pressure isostatic pressing (HIP) processes face inefficiencies in cooling phases, particularly at high cooling rates, where the effectiveness of pressure medium cooling is reduced due to partial flow diversion through non-forced convection paths, leading to uneven temperature distribution and increased internal stresses in treated articles.
Innovation Solution
A press apparatus with a pressure vessel design incorporating an outer convection loop and pressure medium guiding passages that allow for controlled cooling by directing pressure medium flow close to the vessel walls, ensuring effective heat transfer and maintaining high cooling rates without complete restriction of natural convection loops, which helps in maintaining metallurgical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a forced convection loop is used to cool the pressure medium rapidly, then the cooling rate is improved, but the pressure medium flow may divert through natural convection paths reducing cooling effectiveness
Solution Approach 1:
The pressure vessel is divided into distinct zones: a load compartment for articles, a furnace chamber surrounding the load compartment, and a cooling channel system with separate forced and natural convection paths. This segmentation allows independent control of cooling mechanisms and prevents flow short-circuiting by directing forced convection flow through dedicated channels that do not intersect with natural convection loops.
Solution Approach 2:
Different regions of the pressure vessel are assigned different thermal functions: the furnace chamber provides heating, the cooling channels provide forced convection cooling, and the outer vessel walls facilitate natural convection. The cooling channels are specifically positioned to maximize heat transfer from the load compartment while maintaining separate flow paths that prevent mixing of forced and natural convection currents.
2Productivity
If the cooling rate is increased to reduce treatment time, then productivity is improved, but temperature uniformity within the load compartment deteriorates causing internal stresses
Solution Approach 1:
The cooling system transitions from a single-loop design to a multi-dimensional cooling architecture with forced convection channels arranged both vertically and horizontally around the load compartment. This three-dimensional cooling network ensures uniform heat extraction from all regions of the load compartment simultaneously, maintaining temperature uniformity even at high cooling rates.
Solution Approach 2:
The pressure medium serves as an intermediary heat transfer medium between the load compartment and the cooling system. By circulating this medium through specifically designed cooling channels with optimized flow characteristics, the system achieves rapid heat extraction while maintaining uniform temperature distribution through controlled flow velocity and channel geometry.
3Manufacturing precision
If natural convection loops are completely restricted to improve cooling control, then cooling precision is improved, but metallurgical properties of treated articles deteriorate
Solution Approach 1:
The system dynamically switches between forced convection and natural convection modes depending on the treatment phase. During rapid cooling phases, forced convection dominates with high flow rates through dedicated channels. During holding or slower cooling phases, natural convection is permitted to maintain temperature uniformity and support metallurgical quality. The system adapts flow rates and channel utilization based on real-time temperature requirements.
Solution Approach 2:
Both forced and natural convection pathways remain continuously available throughout the treatment cycle, allowing seamless transition between cooling modes. The pressure medium continuously circulates through the entire system, maintaining thermal contact with the load compartment at all times, while the relative contribution of forced versus natural convection is adjusted to meet instantaneous cooling requirements without interrupting the overall cooling action.
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 solution enables efficient cooling of the pressure medium during high-rate cooling phases, reducing internal stresses and maintaining the quality of treated materials by ensuring uniform temperature distribution and effective heat transfer, thus enhancing the metallurgical properties of the treated articles.
Implementation Method 1
at least one outer convection loop pressure medium guiding passage in fluid communication with the furnace chamber and arranged to form an outer convection loop within the pressure vessel. The outer convection loop is arranged to guide the pressure medium after having exited the furnace chamber in proximity to an inner surface of wall(s) of the pressure vessel
Implementation Method 2
a pressure medium flow generator, arranged within the pressure vessel and in fluid communication with the furnace chamber. At least during a cooling phase of the treatment cycle, the pressure medium flow generator is arranged to generate a transport of pressure medium from at least the space between the furnace chamber and the bottom end closure into the furnace chamber, so as to cool the pressure medium in the treatment space
Implementation Method 3
Some of the pressure medium passages may form a natural convection loop within the pressure vessel
Data Source
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AI summary
A press apparatus (100) is disclosed. The press apparatus comprises a pressure vessel (1, 8, 9), arranged to hold pressure medium therein during use of the press apparatus. The pressure vessel comprises a top end closure (8) and a bottom end closure (9). A furnace chamber (18) is arranged within the pressure vessel so that pressure medium can enter and exit the furnace chamber, the furnace chamber at least in part defining a treatment space (19) arranged to accommodate at least one article (5). The press apparatus comprises at least one outer convection loop pressure medium guiding passage (10, 11) in fluid communication with the furnace chamber and arranged to form an outer convection loop within the pressure vessel. The outer convection loop is arranged to guide the pressure medium after having exited the furnace chamber in proximity to an inner surface (23) of wall(s) (22) of the pressure vessel to a space (16) between the furnace chamber and the bottom end closure. At least one pressure medium guiding passage (21) is arranged within the pressure vessel such that pressure medium may pass from the furnace chamber to the space between the furnace chamber and the bottom end closure, or vice versa, via only the at least one pressure medium guiding passage.