Inductive Welding Band for Plastic Jacketed Pipe Joints
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Solution Overview
Problem
Low temperatures of the medium pipes during pipe connection in district heating systems lead to poor quality foam insulation due to moisture condensation, as the existing methods do not effectively prevent condensation at the connection point.
Innovation Solution
Inductive heating of the medium pipes using the same or additional weld tapes around the socket area without a metal insert, ensuring the foam comes into contact with heated pipes and preventing unwanted condensation, while inductively welding the sleeve to the outer pipes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inductive welding is performed on the socket to the outer pipe using a metal insert, then a tight connection is achieved, but the medium pipes remain cold and cause moisture condensation
Solution Approach 1:
The welding band is divided into functionally distinct zones: a first region with metal insert for inductive welding of the socket to the outer pipe, and a second region without metal insert for inductive heating of the medium pipes. This segmentation allows simultaneous achievement of both connection quality and temperature maintenance.
Solution Approach 2:
Different regions of the welding band are designed with different local properties: the first region contains metal insert for welding while the second region is metal-free for heating. This local differentiation enables the band to perform both welding and heating functions at different locations along its length.
2Device complexity
If a single welding band is used for both welding and heating, then device complexity is reduced, but the precision of each function may be compromised
Solution Approach 1:
A single welding band is designed to perform multiple functions: it contains both a metal insert region for inductive welding and a metal-free region for inductive heating. This multi-functional design reduces device complexity while maintaining functional precision through spatial differentiation of tasks within the same component.
3Manufacturing precision
If the medium pipes are heated during foaming, then foam quality is improved by preventing condensation, but additional energy is required
Solution Approach 1:
The heating function is merged into the existing welding band structure by creating a metal-free second region that generates eddy currents for heating when exposed to the induction field. This combines welding and heating operations into a single energy input event, improving foam quality without requiring a separate heating step.
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 method ensures high-quality foam insulation by maintaining the medium pipes above the dew point temperature, preventing condensation and enhancing the connection quality, especially in cold weather conditions.
Implementation Method 1
the medium pipes welded to one another are inductively heated in the connection area. This is accomplished by placing the same weld tape that is used to inductively weld the socket to the outer tube, or at least one additional weld tape, around the socket in the area where no metal insert has been placed between the socket and the outer tube
Implementation Method 2
Since there is no metal insert in the area of this welding band, corresponding eddy currents are induced in the medium pipes, which lead to the desired heating of the medium pipes connected to one another
Implementation Method 3
inductively welding the socket to the outer pipe by means of a welding band placed around the socket
Implementation Method 4
The heat of the eddy currents induced in this metal insert leads to a melting of the socket and outer pipe in the connection area, with the melt penetrating the metal insert and, after solidification, ensuring a tight, tight connection between the outer pipe and socket
Implementation Method 5
After welding, the cavity between the socket and the medium pipe is filled with foam through one or more openings in the socket. A suitable PU foam is usually used here
Data Source
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AI summary
A method and a device for joining plastic-jacketed pipes are described. After welding the abutting inner pipes (1) of the plastic-jacketed pipes, a sleeve (6) made of thermoplastic material is inductively welded onto the two outer pipes (4) of the plastic-jacketed pipes. Before or during the foaming of the cavity (3) above the joint of the inner pipes (1), the inner pipes (1) are inductively heated to ensure good insulating foam quality even in cold weather. In the joining device, the induction welding device has at least one additional welding strip (8) for inductively heating the inner pipes. In another embodiment, the induction device has a wide welding strip that includes at least one conductor section for inductively welding the sleeve (6) and at least one conductor section for inductively heating the inner pipes (1).