A Model for Predicting Temperature of Electrofusion Joints for Polyethylene Pipes

Shi, Jianfeng; Zheng, Jinyang; Guo, Weican; Xu, Ping; Qin, Yongquan; Zuo, Shangzhi

doi:10.1115/1.4000202

Cited by 20 publications

(9 citation statements)

References 9 publications

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“…And though the joint has been welded together with the welding time of 33 s, it failed immediately when the testing pressure rise. According to the results of our previously developed temperature analysis model,3 when welding time is 22 s, temperature at the pipe‐fitting interface is much less than that at the melting point of PE. And when welding time last for 33 s, temperature at the fusion interface is just surpassed the melting point of PE, and EF joint is just formed without developing any strength.…”

Section: Resultsmentioning

confidence: 99%

“…The cold welding defect is usually caused by insufficient welding time or welding power. The joints of cold welding usually seem to be identical with normally welded joints, but the mechanical properties and long‐time performance do not reach as those of good joints 2, 3…”

Section: Classification Of Defectsmentioning

confidence: 99%

“…The influence of welding voltage, welding time, clearance between pipes, and fitting to the mechanical properties of EF joint was also analyzed in detail. By considering the temperature‐dependent properties of PE and the variation of power input with the temperature of the resistance, Zheng3 studied the influence of welding parameters to the temperature at the fusion interface during EF welding. Also, the appropriate cooling time after EF welding is determined by Higuchi 4.…”

Section: Introductionmentioning

confidence: 99%

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Defects classification and failure modes of electrofusion joint for connecting polyethylene pipes

Shi

Zheng

Guo

et al. 2011

J of Applied Polymer Sci

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As electrofusion (EF) technology is widely used in connecting polyethylene (PE) pipes and other plastic pipes or composite pipes, research in safety assessment of EF joints has been of major concern. EF joints with defects are very common in practical applications. These defects may greatly reduce the mechanical performance of the EF joints and threat safety running of the pipeline system. To evaluate hazard of these defects and provide a basic understanding for the failure mechanism of EF joints, a comprehensive study on defects and failure modes is conducted in this work. The defects in EF joints are classified into four categories: poor fusion interface, over welding, voids, and structural deformity. The forming reasons of these defects are analyzed in detail. The mechanical properties of EF joint containing these defects are investigated by conducting peeling tests and sustained hydraulic pressure tests. Test results show that there are three main failure mode of EF joint under inner pressure, that is, cracking through the fusion interface, cracking through the fitting, and cracking through copper wire interface.

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Section: Resultsmentioning

confidence: 99%

Section: Classification Of Defectsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Defects classification and failure modes of electrofusion joint for connecting polyethylene pipes

Shi

Zheng

Guo

et al. 2011

J of Applied Polymer Sci

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“…This way, the internal temperatures of the optical fiber microduct made of HDPE and its surrounding layers of LDPE were computed. The thermal properties of HDPE and LDPE materials are not constant in the temperature range 25˚C to 180˚C [11], therefore the computed LTspice thermal model was optimized to give the best fit for the measured temperatures with 50µm K-type thermocouples [17]. The optimized LTspice thermal model of heat generation and propagation inside the optical fiber microduct [17] is reproduced in Figure 6 [17].…”

Section: B Previous Workmentioning

confidence: 99%

Design and Development of a Battery Powered Electrofusion Welding System for Optical Fiber Microducts

et al. 2020

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At present, optical fiber microducts are coupled together by mechanical types of joints. Mechanical joints are thick, require a large space, and reduce the installation distance in multi-microduct installation. They may leak or explode in the blown fiber installation process. Mechanical joints are subjected to time dependent deterioration under long service times beneath the earth's surface. It may start with a small leakage, followed by damage due to water freezing inside the optical fiber microduct. Optical fiber microducts are made up of high-density polyethylene, which is considered most suitable for thermoelectric welding. For thermoelectric welding of two optical fiber microducts, the welding time should be one second, and should not cause any damage to the inner structure of the microducts that are being coupled. To fulfill these requirements, an LTspice simulation model for the welding system was developed and validated. The developed LTspice model has two parts. The first part models the power input to joule heating wire and the second part models the heat propagation inside the different layers of the optical fiber microduct and surrounding joint by using electro-thermal analogy. In order to validate the simulation results, a battery powered prototype welding system was developed and tested. The prototype welding system consists of a custom-built electrofusion joint and a controller board. A 40 volt 4 ampere-hour Li-Ion battery was used to power the complete system. The power drawn from the battery was controlled by charging and discharging of a capacitor bank, which makes sure that the battery is not overloaded. After successful welding, a pull strength test and an air pressure leakage test were performed to ensure that the welded joints met the requirements set by the mechanical joints. The results show that this new kind of joint and welding system can effectively replace mechanical joints in future optical fiber duct installations.

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“…For this reason the thermal LBM with the Boussinesq approximation is employed to simulate natural-convection and heat conduction. The schematic sketch of an EF coupler [18] and schematic sketch of an EF model are shown in fig. 2.…”

Section: Introductionmentioning

confidence: 99%

Optimization of conjugate heat transfer in the electrofusion joint using Taguchi method

et al. 2019

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Applications of electrofusion joints for gas pipes are increasing and so study on temperature distribution in these joints have an important role in polyethylene welding. The objective of this study is assessment of optimum rate of the conjugate heat transfer in electrofusion joints. The simulations were planned based on Taguchi's L25 orthogonal array. The thermal lattice Boltzmann based on D2Q9 method was employed to simulate the flow and thermal fields. Signal-to-noise ratios analysis were carried out. The flow behaviors and the rate of heat transfer in terms of the Nusselt number have effectively changed by distance, height and radius of electrical wires inside the electrofusion joint. Finally, result analysis verified that Taguchi method achieved optimization of heat transfer rate with sufficient accuracy.

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A Model for Predicting Temperature of Electrofusion Joints for Polyethylene Pipes

Cited by 20 publications

References 9 publications

Defects classification and failure modes of electrofusion joint for connecting polyethylene pipes

Defects classification and failure modes of electrofusion joint for connecting polyethylene pipes

Design and Development of a Battery Powered Electrofusion Welding System for Optical Fiber Microducts

Optimization of conjugate heat transfer in the electrofusion joint using Taguchi method

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