Vulcanization or Other Heat Treatment by Electrical Conduction

1944 ◽  
Vol 17 (1) ◽  
pp. 188-191
Author(s):  
Felix L. Yerzley
Keyword(s):  
Heat Treatment ◽  
Electric Current ◽  
High Frequency ◽  
Direct Consequence ◽  
Electrical Energy ◽  
Internal Resistance ◽  
Appreciable Amount ◽  
Rubber Belt ◽  
High Dielectric ◽  
Electrical Conductors

Abstract This communication relates to the heating of plastic materials of. a semiconducting nature by passing electricity through them. In particular, it relates to the vulcanization of rubber and rubberlike materials, including Neoprene, with heat generated by the conduction of an electric current and, similarly, it relates to the heat treatment of thermosetting plastics by conduction of an electric current. It is well known that all electrical conductors are heated to some extent by the passage of an electric current. This heating is a direct consequence of internal resistance. The effect so obtained is proportional to the electrical energy absorbed, and is expressed by the equation: power=I2R, in which I is the current in amperes between two points and R is the corresponding resistance in ohms. The unit of power is the watt. Others have used electrical means of heating unvulcanized rubber, but the disclosures differ fundamentally from this proposal. For example, Neerlye coils a steel ribbon and an uncured rubber belt in a spiral and heats the coil by passing electricity through the steel. Newton claims vulcanization by abeam of electrons from a cathode ray tube. The most significant disclosure is by Dufour. This claims the “process for the vulcanization of rubber characterized by the feature that the rubber to be heat-treated is arranged as a dielectric between the electrodes of an electric condenser to which there is applied a high frequency alternating current of a periodicity of several million cycles per second”. This patent is characterized by utilization of high-frequency fields of the order of several megacycles per second. Further, it is not required in induction curing with high-frequency current that the electrodes be in actual mechanical contact with the rubber. Induction curing is facilitated when the material to be heated has both a high power factor and a high dielectric constant, but high electrical conductivity of appreciable amount is not essential to the application of the method.

scholarly journals STUDIES IN HYPERTHERMIA INDUCED BY THE HIGH FREQUENCY ELECTRIC CURRENT

1930 ◽  
Vol 85 (3) ◽  
pp. 675-686
Author(s):  
Fritz Bischoff ◽  
H.J. Ullmann ◽  
Elsie Hill ◽  
M. Louisa Long
Keyword(s):  
Electric Current ◽  
High Frequency

scholarly journals Failure Analysis of Rheocast Cylinder Head Covers of Hypereutectic Al–Si Alloys

2020 ◽  
Author(s):  
Jian Feng
Keyword(s):  
Heat Treatment ◽  
Surface Morphology ◽  
Service Time ◽  
Shot Peening ◽  
High Frequency ◽  
Cylinder Head ◽  
Die Casting ◽  
Fatigue Properties ◽  
Homogeneous Distribution ◽  
Engine Components

AbstractThe purpose of the present study is to determine the cause of failures of semisolid rheocast cylinder head covers of hypereutectic modified LM30 alloys. The covers, manufactured by rheocasting, a process that consists of the incorporation and homogeneous distribution of the reinforcements in semisolid metal (SSM) before die casting, were shot-peened after heat treatment to increase the fatigue resistance. However, these engine components failed during operation after a short service time. The major flaws were located by radiography. The microstructure was controlled by metallography. Significant interactions between shot peening and surface/subsurface contaminants were identified by surface morphology and fractography. The fatigue properties of hypereutectic alloys were investigated by a high-frequency vibrophore. It was identified that the failure was related to the cleanliness of SSM as well as the rheocasting process. Recommendations were given to prevent the recurrence of similar failures.

The measuring system for monitoring the microarc heating process during surface hardening of steel products

2021 ◽  
pp. 33-39
Author(s):  
Makar S. Stepanov ◽  
rina G. Koshlyakova
Keyword(s):  
Heat Treatment ◽  
Mathematical Model ◽  
Electric Current ◽  
Measurement Method ◽  
Sample Surface ◽  
Steel Sample ◽  
Measuring System ◽  
Heating Process ◽  
Carbon Powder ◽  
Measured Temperature

The accelerated heat treatment during steel products hardening technology has been investigated. The possibility of measuring the temperature of steel products by thermoelectric platinum-platinum-rhodium thermocouple under microarc heating conditions is analyzed. During the experiments, working junctions of two S-type thermocouples: working and standard, were coined into the sample surface at the same level. The free thermocouples ends were connected to a digital multimeter and a personal computer. It was determined that 5 factors affect the measurement results: the electric current strength in the circuit, carbon powder, calibration, number of repeated measurement cycles, and a thermocouple copy. When planning the experiment, the concept of conducting a step-by-step nested experiment was used. Variance analysis method was used to process the experimental results. The measurement method precision parameters were calculated: repeatability and reproducibility. A linear mathematical model linking the measurement method reproducibility index with the measured temperature value has been obtained. A linear mathematical model is obtained that relates the reproducibility index of the measurement method to the measured temperature value. A measuring system for the experimental determination of the temperature of a steel sample is proposed and its application is justified for different electric current densities on the sample surface and varying duration of microarc heating. The possibilities of selecting and controlling the microarc heating modes depending on the required temperature of the heat treatment of the steel product are determined.

scholarly journals Factors affecting the temperature increasing rate in arc-shaped bamboo pieces during high-frequency heating

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 2656-2667
Author(s):  
Feihu Chang ◽  
Yanhe Liu ◽  
Bin Zhang ◽  
Wansi Fu ◽  
Pengfei Jiang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Moisture Content ◽  
Electric Field ◽  
Heating Rate ◽  
High Frequency ◽  
Great Influence ◽  
Chord Length ◽  
High Frequency Electric Field ◽  
Frequency Electric Field ◽  
Frequency Heating

In the process of applying the high-frequency heating technology to bamboo heat treatment, controlling the material temperature has a great influence on the quality of bamboo forming. Therefore, research on the heat transfer mechanism of high-frequency heating of arc-shaped bamboo pieces is of great importance. In this paper, the influence of different moisture content, chord length, and plate voltage on the heating rate of arc-shaped bamboo pieces under high-frequency electric field were studied. The moisture content of bamboo had the most remarkable effect on the heating rate. With increased moisture content, the temperature rose faster. The selection of the plate voltage had an obvious influence on the heating. If the voltage was low, the heating rate was too slow, the heating time was long, or the voltage was high, it was easy to cause electric field breakdown and damage the bamboo pieces. As the chord length decreased, the heating rate gradually increased. When the radian of the arc-shaped bamboo pieces could be ignored, the heating rate was the fastest. The results showed that under certain conditions, the arc-shaped bamboo pieces showed a good heat treatment effect in a high-frequency electric field.

scholarly journals DESIGNING A SINGLE PHASE INVERTER TO CALCULATE PUBLIC ROADS LIGHTING EFFICIENCY USING SODIUM LAMP TYPES

2018 ◽  
Vol 1 ◽  
Keyword(s):  
High Frequency ◽  
Single Phase ◽  
Electrical Energy ◽  
Lighting System ◽  
Phase Inverter ◽  
Road Lighting ◽  
Public Road ◽  
Sodium Lamp ◽  
Single Phase Inverter ◽  
Design And Manufacture

An inverter is a circuit which converts the AC voltage into DC voltage. Current use of inverters is very large, especially in industries, offices and housing. Even though now there are many inverter markets, but many are used for household loads, no one uses an inverter for roads lighting system namely sodium lamp because it requires a high frequency and voltage Then the surveyors placed a single phase inverter from the sodium lamp. Single phase inverter tool designed produces a voltage of 10,000 V, Amperage current of 0.20 A and 2000 w Power when tested against overloaded and not overloaded inverter, the results are quite good but in the design and manufacture of a single phase inverter is still lacking, which is only able to start the initial lighting of the sodium lamp because the current is small and the resulting voltage is unstable. Keywords: Single phase inverter, electrical energy, public road lighting, sodium lamp.

Selecting the Switching Frequency of the 6500 V IGBT High Voltage DC Converter

2021 ◽  
pp. 21-27
Author(s):  
Sergey I. Volskiy ◽  
◽  
Yuri Yu. SKOROKHOD ◽  
Nikolay Echkilev ◽  
◽  
...  
Keyword(s):  
High Voltage ◽  
High Frequency ◽  
Electrical Energy ◽  
Input Voltage ◽  
Switching Frequency ◽  
Energy Transformation ◽  
Power Losses ◽  
Voltage Converter ◽  
Passenger Cars ◽  
Power Circuit

The high-voltage converter with the input voltage of 3000 V DC is considered for use as a power supply for auxiliary circuits of commuter electric trains and passenger cars that are used on Russian railways. The limitations on the use of semiconductor devices in converters with an input voltage of 3000 V are shown. The power electrical circuits of the input units of the considered high-voltage converters are shown when using of 1700 and 6500 V IGBT. The expressions for calculating the power losses and the algorithm for selecting the switching frequency of 6500 in IGBT are given. This article is of interest to developers of high-voltage DC converters with an input voltage of 3000 V and higher, which choose IGBT for the power circuit of input units with using the high frequency principle of the electrical energy transformation.

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