Induction and Irradiation Heating for Coated Metal Pipes
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Solution Overview
Problem
Existing methods for heating metal pipes with insulating polyolefin coatings during pipeline connections face challenges in achieving uniform temperature due to differing material expansion coefficients and require cooling systems, leading to inefficient coating application and potential detachment.
Innovation Solution
A device utilizing induction heating for the metal pipe and irradiation heating for the coated sectors, with adjustable metal rings or hollow annular bodies for balanced temperature control, eliminating the need for a cooling system and ensuring even heating across different material zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If both the metal pipe and the polyolefin coating are heated to the same temperature using conventional heating methods, then the coating can be properly applied, but the heating process becomes extremely difficult and time-consuming due to the insulating properties of polyolefins
Solution Approach 1:
The heating process is segmented into two distinct zones: a first heating zone for the metal pipe and a second heating zone for the polyolefin coating. This is achieved through separate heating elements (induction heater for metal, radiant heater for coating) that can be independently controlled, allowing each material to be heated to the required temperature simultaneously without waiting for the insulating coating to conduct heat
Solution Approach 2:
Different heating methods are applied to different zones based on the specific thermal requirements of each material. The metal pipe receives induction heating optimized for conductive materials, while the polyolefin coating receives radiant heating optimized for insulating materials. This localized quality approach ensures each material receives the appropriate heating intensity and method
2Productivity
If intense localized heating is applied to heat the metal pipe, then the heating efficiency is high, but the polyolefin coating detaches from the pipe due to differential thermal expansion
Solution Approach 1:
The heating system is divided into separate heating zones with independent control: induction heating elements for the metal pipe and radiant heating elements for the coating. This segmentation allows the metal to be heated efficiently through induction while the coating is gently heated through radiation, preventing excessive thermal stress and differential expansion that would cause detachment
Solution Approach 2:
The heating parameters (temperature, heating rate, heating method) are changed and optimized for each material zone. The metal pipe is heated to a higher temperature through induction, while the coating is heated to a lower temperature through radiant heating. This parameter optimization ensures both materials reach their required temperatures without causing coating detachment
3Temperature
If a cooling system is installed to control temperature during pipeline connections, then temperature control is improved, but the device complexity and costs increase significantly
Solution Approach 1:
The cooling system is completely removed from the pipeline connection process. Instead of heating both materials uniformly and then cooling them, the invention extracts the cooling step entirely by using differentiated heating zones that prevent overheating in the first place. This eliminates the need for complex cooling infrastructure while maintaining temperature control
Solution Approach 2:
The heating process is designed with preliminary action by pre-heating the metal pipe to a higher temperature before coating application, and simultaneously heating the coating to its required temperature. This preliminary heating optimization ensures both materials are at the correct temperatures for coating application without requiring subsequent cooling
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
Achieves uniform temperature across metal and coated areas, preventing coating detachment and ensuring reliable, long-lasting protective coatings during pipeline connections without the need for cooling systems.
Implementation Method 1
a first heating device (20) arranged to heat, directly by induction, a central zone (14) of the metal pipe (12)
Implementation Method 2
heating directly by induction a central zone of the metal pipe
Implementation Method 3
a second heating device (24) arranged to heat, indirectly and simultaneously by irradiation, the sectors (16, 18) adjacent to said central zone (14)
Data Source
Figure 1~3
Figure 4~6
Figure 7~9
AI summary
A device (10-10'), (11-11') for the localized heating of parts of metal pipes (12) connected to each other and of parts of primary plastic coating (16'- 18') of the same pipes, all to be coated with protective material, comprises a spiral-wise development winding consisting of one or more coils (20) and of annular means that are arranged within and coaxially to said coil (20), at the parts of primary plastic coating (16'-18'), and that surround each one of said pipes (12) for heating by induction a zone (14) without primary plastic coating and for indirectly heating, by irradiation, end portions of the same provided with plastic coating (16'-18') contiguous to said zone (14).