Segmented Weld Zones in Flexible Plastic Heat Exchange Elements
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Solution Overview
Problem
Prior heat exchangers with sinuous weld configurations face challenges in fluid flow distribution due to bulky top feed channel structures, restricting expansion and heat exchange capacity, while spot welds can lead to clogged pathways and reduced fluid flow.
Innovation Solution
A heat exchange element with an array of spot welds in the uppermost zone for lateral fluid distribution, parallel extended welds in the second zone for fluid flow channels, and oblique welds in the lowermost zone for fluid flow towards the outlet, allowing for improved fluid flow and reduced expansion, enhancing heat exchange efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sinuous weld configurations are used, then fluid flow distribution is improved and pathways are less prone to clogging, but the top feed channel structure becomes bulky, restricting expansion and heat exchange capacity
Solution Approach 1:
The weld configuration is segmented into three distinct zones: spot welds in the uppermost zone for lateral distribution, parallel extended welds in the middle zone for vertical channels, and oblique welds in the lower zone for outlet flow. This segmentation allows each zone to perform its specific function efficiently without requiring bulky structures throughout the entire element.
Solution Approach 2:
Different weld patterns are applied to different zones based on local flow requirements. Spot welds provide lateral distribution where needed, parallel welds create vertical channels in the middle section, and oblique welds guide flow to outlets at the bottom. This local optimization eliminates the need for uniformly bulky sinuous welds throughout the entire element.
2Ease of manufacture
If spot welds are used, then the structure is simpler and manufacturing is easier, but pathways can become clogged and fluid flow is reduced
Solution Approach 1:
The welding process is segmented into three zones with different patterns. The uppermost zone uses simple spot welds for lateral distribution, the middle zone uses parallel extended welds for vertical flow channels, and the lower zone uses oblique welds for outlet flow. This segmentation maintains manufacturing simplicity while ensuring adequate fluid flow paths.
Solution Approach 2:
Different weld patterns are applied locally to different zones based on flow requirements. Spot welds are used only where lateral distribution is needed, while parallel and oblique welds are used in zones requiring vertical and outlet flow respectively. This local optimization maintains ease of manufacture while preventing clogging.
3Area of stationary object
If elements are expanded to increase heat exchange surface area, then heat exchange capacity is improved, but the bulky top feed channel structure prevents sufficient expansion
Solution Approach 1:
The element structure is segmented into three zones with different weld patterns that optimize for their specific functions. This segmentation allows the element to expand more efficiently in the heat exchange zones without being constrained by bulky feed channel structures, as the simplified weld patterns reduce material requirements and allow greater flexibility.
Solution Approach 2:
Different weld patterns are applied to different zones to optimize local properties. The uppermost zone uses spot welds that allow greater expansion freedom, while the middle and lower zones use patterns optimized for their specific flow functions. This local optimization enables sufficient element expansion to increase heat exchange surface area.
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 configuration ensures efficient fluid distribution and increased heat exchange surface area without clogging, supporting high-pressure conditions and self-cleaning capabilities, while minimizing expansion requirements for increased heat exchange capacity.
Implementation Method 1
an array of welds bonding the opposite plastic films to define routes for vertical fluid flow through subsequent heat exchange zones inside the bag
Implementation Method 2
Heat exchange element of flexible plastic film material bonded to form an expandable bag
Implementation Method 3
The heat exchange between the inside and the outside of the adjacent elements condenses the vapor back to liquid
Implementation Method 4
an array of welds bonding the opposite plastic films to define routes for vertical fluid flow
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a heat exchange element (1 ) of flexible plastic film material, a heat exchanger made up of such elements, and an equipment for the manufacture of the elements. The element (1 ) comprises a pair of opposite film sheets bonded by welds (4, 5, 6) to form an expandable bag with inside and outside heat exchange surfaces, an inlet opening (2) for supplying a pressurized heat exchange fluid to the bag, an outlet opening (3) for discharging the fluid from the bag after heat exchange, and an array of welds (4, 5, 6) defining routes for fluid flow inside the bag. According to the invention there are spot welds (4) in a first zone (7) of the element, parallel extended welds (5) in a second zone (8) of the element, defining fluid flow channels (11 ) through the second zone, and oblique welds (6) in a third zone (9) of the element, defining channels (12) for fluid flow towards the outlet opening (3). The heat exchanger comprises a pack of adjacent elements (1 ) for heat exchange between a pressurized first fluid flowing inside the elements and a second fluid flowing between the adjacent elements. In the equipment for the manufacture of the elements (1 ) a web of double plastic sheet material is made to pass a succession of three heatable weld rolls and a backing roll. The weld rolls have protrusions for forming welds of three different configurations, respectively, and are provided with means for selectively bringing the rolls into contact with the moving web and out of contact with it.