• Journal of the Korea Institute of Building Construction
• /
• v.14 no.2
• /
• pp.163-169
• /
• 2014

Engineers in the construction field have been using bonded waterproofing sheets in an attempt to resolve the imbalance in the quality, the risk of fire, safety of workers, and environmental pollution, as well as to eliminate separate use of organic adhesives on the surface of concrete. Recently, self-laminated waterproofing sheets have been developed. The purpose of this research is to find an appropriate processing speed according to the changes in physical properties, and visual observation of the waterproofing sheets laminated by the aluminum thin-film and viscosity layer that can be attached through self-adhesiveness on the surface of concrete and waterproofing sheets. Therefore, this research is conducted using a physical performance test. Based on the result of the test, when the high-frequency inductive heating apparatus was used, an improved adhesion and bonding stability effect were confirmed after the anti-hydrostatic pressure and bond strength in the temperature condition, and the surface observation in the processing speed condition.

• Korean Journal of Metals and Materials
• /
• v.48 no.11
• /
• pp.1009-1013
• /
• 2010

Extremely dense WC with a relative density of up to 99% was obtained within five minutes under a pressure of 80 MPa using the High-Frequency Induction Heated Sintering method. The average grain size of the WC was about 71 nm. The advantage of this process is not only rapid densification to obtain a neartheoretical density but also the prohibition of grain growth in nano-structured materials. The hardness and fracture toughness of the dense WC produced by HFIHS were $2660kg{\cdot}mm^{-2}$ and $7.2MPa{\cdot}m^{1/2}$, respectively.

• Journal of the KSME
• /
• v.51 no.4
• /
• pp.50-54
• /
• 2011

이 글에서는 고주파 유도가열(High-frequency induction heating)을 사용하여 사출금형 표면을 급속으로 가열하기 위한 기술을 소개하고, 국내외 적용사례(마이크로 패턴의 성형성 향상, 외관제품의 표면특성 향상 등)에 대해 소개하고자 한다.

• Resources Recycling
• /
• v.21 no.3
• /
• pp.48-55
• /
• 2012

Recently, the recycling with environmentally friendly method has been an issue for various fields. An effective removal method of coating layers from coated copper wires is one critical factor for recycling copper wire. We have adopted a high frequency heating routine for removing the coating layers on the coated copper wires, and attempted to find optimum conditions. The experimental results show that the copper wires should be maintained at or above $950^{\circ}C$ for rapid removal of the polyester. The simulation and experimental results are discussed with respect to the microstrucrual evolution during heating of the copper wires.

• Proceedings of the KIPE Conference
• /
• 1998.10a
• /
• pp.586-591
• /
• 1998

This paper presents an innovative prototype of a new conceptual electromagnetic induction-based fluid heating appliance using voltage-fed series capacitor-compensated load resonant high-frequency IGBT inverter with a phase-shifted PWM and a power factor correction schemes. Its operating characteristics in steady-state and dynamic state are illustrated including unique features and evaluated on the basis of its computer simulation and experimental results of 10kw breadboard appliance developed for hot water producer and superheated steamer.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.8 no.2
• /
• pp.43-49
• /
• 1998

This paper describes a phase-shift pulse-width modulation and pulse-frequency modulation seriesresonant high-frequency inverter using IGBT for the power control of high-frequency inductionheating using fuzzy, which is practically applied for 2 0- 5~0 0~~ ~in 1d uction-heating and meltingpov~er supply in industrial fields. The adaptive frequency tracking based phase-shifting PWMregillation scheme is presented in order to minimize switching losses. The trially-producedbreadboards using IGBT are succesfully demostrated and discussed.discussed.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• v.5B no.2
• /
• pp.181-188
• /
• 2005

In this paper, a DC smoothing filterless soft switching pulse modulated high frequency AC power conversion circuit connected to utility. frequency AC power source is proposed for consumer induction heating hot water producer, steamer and super heated steamer. The operating principle of DC link filterless utility frequency AC-high frequency AC (HF AC) power conversion circuit defined as high frequency cycloinverter is described, which can operate under a principle of ZVS/AVT and power regulation based on alternate asymmetrical PWM in synchronization with the utility frequency single phase AC positive or negative half wave voltage. The dual mode modulation control scheme based on high frequency PWM and commercial frequency AC voltage PDM for the proposed high frequency cycloinverter are discussed to enlarge its soft switching commutation operating range for wide HF AC power regulation. This high frequency cycloinverter is developed for high frequency IH Dual Packs Heater (DPH) type boiler used in consumer and industrial fluid pipeline systems. Based on the experiment and simulation results, this high frequency cycloinverter is proved to be suitable for the consumer use IH-DPH boiler and hot water producers. The cycloinverter power regulation and power conversion efficiency characteristics are evaluated and discussed.

• Proceedings of the KIEE Conference
• /
• 1996.07a
• /
• pp.489-491
• /
• 1996

This paper describes the Induction-beating high frequency resonant Inverter(0.5MHz, 2KW) with full-bridge circuit using Power-MOSFET. In this paper can be applied to several areas such as induction heating, development of power supply in industrial process etc.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2003.10a
• /
• pp.39-40
• /
• 2003

1) Using a developed high-frequency induction heated sintering method, the rapid densification of WC-Co hard materials was accomplished using ultra fine powders with 260 nm size within 1 minute. 2) The relative density of the composite was 99.5% for the applide pressure of 60MPa and the induced current for 90% output of total capacity. 3) The grain size of WC-Co hard materials is about 260nm and the average thickness of the binder phase determined is about 11nm. The fracture toughness and the hardness of this work 12 $MPa{\cdot}nm^2$, respectively. 4) Using pressureless sintering, we produced dense WC-Co hard materials with a relative density of 97% without applying pressure.

• Journal of the Korean Society for Precision Engineering
• /
• v.33 no.5
• /
• pp.393-400
• /
• 2016

High frequency induction heating (HFIH) is used in many industries and has a number of advantages, including reliability and repeatability. It is a non-contact method of providing energy-efficient heat in the minimum amount of time without using a flame. Recently, HFIH has been actively studied using the finite element method (FEM), however, these studies only focused on the accuracy of the analysis. In this paper, we can measure joule heat distributions by the electromagnetic analysis for HFIH and the temperature distribution from the heat transfer analysis by applying joule heat for a sprocket. The sprocket is heated over $850^{\circ}C$ due to joule heat and then cooled to under $200^{\circ}C$ by using cooling $20^{\circ}C$ water. These processes were used to calculate the FEM and then compared to our experimental results. The calculated outcome may be used to predict hardening depth in HFIH.