Twisted Pipe Heat Exchanger Insulation
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Solution Overview
Problem
Conventional twisted tube heat exchangers face issues with increased material costs due to extrusion-based heat insulator installation, which is impractical for their complex shape, leading to corrosion from thermogalvanic cells formed by condensed water bridging between pipes.
Innovation Solution
A heat exchanger design where a heat insulator is wound around the boundary region between joined and unjoined areas of the twisted tube, covering the peripheries of both pipes to prevent corrosion and reduce material usage by avoiding extensive extrusion-based insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resin layer is formed by extrusion process to cover the peripheries of both pipes, then the heat insulator is installed on the entire heat exchanger, but material costs increase
Solution Approach 1:
The patent applies heat insulation only to specific areas where condensation is most likely to occur (the first area with joined pipes and boundary region), rather than covering the entire heat exchanger. This localized approach maintains necessary thermal protection while reducing resin material usage and costs.
Solution Approach 2:
The heat exchanger surface is divided into distinct areas (first area with joined pipes, second area without joined pipes, and boundary region). The heat insulator is selectively applied to the first area and boundary region, segmenting the insulation application to match the actual corrosion risk zones.
2Adaptability or versatility
If the second pipe is installed spirally on the periphery of the first pipe, then the heat exchanger has a twisted tube configuration, but it becomes practically impossible to form a resin layer by extrusion process
Solution Approach 1:
Instead of forming the heat insulator by extrusion process (which works for simple linear configurations), the patent winds the heat insulator around the twisted tube configuration. This inverted approach to insulator application matches the complex spiral geometry of the heat exchanger.
Solution Approach 2:
The heat insulator is applied as a flexible winding that can conform to the spiral configuration of the twisted tube heat exchanger, rather than using rigid extruded sections that cannot adapt to complex geometries.
3Quantity of substance
If the heat insulator is not installed on the second area, then material costs are reduced, but condensed water bridges between pipes causing corrosion
Solution Approach 1:
The patent identifies that corrosion risk is localized to specific areas where condensation forms and bridges between pipes (first area and boundary region). Heat insulation is applied only to these high-risk zones, providing targeted protection against corrosion while avoiding unnecessary material use in lower-risk areas.
Solution Approach 2:
The patent converts the understanding of condensation patterns and corrosion mechanisms into a beneficial targeted insulation strategy. By identifying where condensation bridges form, the insulation is precisely placed to prevent corrosion at those specific locations.
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 winding method effectively inhibits corrosion by preventing condensed water from bridging between pipes and acting as a thermogalvanic cell, while reducing material costs by only applying insulation to critical areas.
Implementation Method 1
a heat insulator 30 wound around a certain area including the boundary region 43, covering peripheries of the first pipe 10 and the second pipes 20 in the boundary region 43
Implementation Method 2
a second pipe having a part wound around the spiral groove on the first pipe and allowing refrigerant that heats the first fluid to flow through the second pipe
Implementation Method 3
the section of the first pipe that is located in the second area is at a lower temperature than ambient temperature and tends to cause condensation
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A twisted tube heat exchanger includes a twisted tube, and a heat insulator. The twisted tube includes a first pipe having a spiral groove formed on a periphery of the first pipe and allowing a first fluid to flow through the first pipe, and a second pipe having a part wound around the spiral groove on the first pipe and allowing refrigerant that heats the first fluid to flow through the second pipe. An area in which the first pipe and the second pipe are joined together is defined as a first area, and an area that is located closer to an end side of the first pipe than is the first area and in which the first pipe and the second pipe are not joined together is defined as a second area. The heat insulator is wound around a certain area including a boundary region between the first area and the second area, covering peripheries of the first pipe and the second pipe in the boundary region and a periphery of the first pipe in the second area.