耐火材料导热系数的测定 应用资料

智能文字提取功能测试中

耐火材料导热系数的测定 应用资料耐火材料是能够承受高温的材料。常规耐火材料大致可分为两种类型：一种是模制和烧结的耐火材料(砖和板)，另一种是现场应用的整体耐火材料(粉末或粘土状)。普通耐火材料根据其导热系数分为耐火砖和耐火保温砖。此应用资料是使用快速热导热系数测定仪测量低热耐火砖的测试结果。KM京都電子工業株式会社KYOTO ELECTRONICSMANUFACTURING CO.，LTD.APTM-0101en APTM-0101en Application Note Refractory Brick Thermal Conductivity Measurement IndustryCeramicInstrumentQuick Thermal Conductivity MeterMeasurement methodHot wire comparative methodStandardGB/T 36133 1. Scope Refractories are materials that can withstand high temperatures. Regular refractories can be approximately classified into two types： those that have been moldedand sintered beforehand (bricks and plates)， and others called monolithic refractories (powderedor clay-like) that are applied on site. Regular refractories are further classified as refractory bricks and refractory insulation bricks，according to their degree of thermal conductivity. In this study， we will introduce the results of measuring the refractory bricks with low thermalconductivity using the Quick Thermal Conductivity Meter. 2. Precautions Avoid trapping air between the sample and the probe when setting. If pockets of air exist， they will affect the thermal conductivity measurement result. ·Prepare a flat specimen with no irregularities or undulations on the sample surface. · If there is dust on the sample surface or probe， wipe it off. For the amount of heat applied to the sample， determine the heater current value so that thetemperature rise during measurement is 5 to 20 °℃. Set the heater current value from [HEATER] on the main unit and select the heater current valueto be used according to the sample. Excessive heating may cause breakage of samples andreferences. Refer to the instruction manual for current value guidelines. Measure the sample by allowing it to fully conform to the measurement environmentaltemperature. 3. Apparatus Main unit Quick Thermal Conductivity Meter (Normal Measurement)Probe PD-13N(Insulated moisture-proof probe) 4.Procedure 1) Place the probe on the sample. 2) Apply constant power (calories) to the heater and at the same time record the change intemperature rise to obtain the thermal conductivity. NOTE： Refer to the instruction manual for details. 5.Example - Measurement principle- Our Quick Thermal Conductivity Meter is a thermal conductivity meter that can performsimple and quick measurement with excellent operability. Measurement begins when the probeis pressed (Fig.1) against a sample surface of uniform temperature， and the operation can becompleted in just 60 seconds. The probe consists of a linear heating element and a thermocouple， and as the constant power(calories) is continuously applied to the heater， the temperature of the heater rises exponentially.When the time axis uses a logarithmic scale， the temperature rise curve becomes a straight line(Fig.2).1g. The slope of this straight line increases with lower sample thermal conductivity， and if thesample has high thermal conductivity， the slope decreases. In other words， the thermalconductivity of the sample can be obtained from the slope of the temperature rise graph inwhich the horizontal time axis has a logarithmic scale. Low thermal conductivity High thermal conductivity Fig1.Probe Fig 2.log(t)vsTemp. graph -Measurement conditions-oAmbient condition 23℃oHeater current value： 1.0AoMeasurement time 60 seconds -Measurement results- These are the measurement results for the thermal conductivity of refractory brick. For the measurements， we attached the probe to the sample and then removed the probe on eachiteration. Measurement was performed three times. Table 1 shows average value， standard deviation and relative standard deviation. Table 1. Measurement result table for refractory bricks Refractory brick Refractory brick 1 Refractory brick 2 Thermal conductivity 0.1337 0.1284 2 Mean value 0.1348 0.1280 Standard deviation 0.0010 0.0003 RSD(%) 0.76 0.25 -Measurement example- Model： QTM-710 Model： QTM-710 Print： 2017/04/26 15：28 Page： 1/1 6. Summarv Good accuracy was confirmed in which relative standard deviation of refractory bricks was 1%or less. Although refractory brick 1 and refractory brick 2 are the same material， it can be confirmed thatthere is a slight difference in thermal conductivity. The difference in thermal conductivity between the two refractory bricks is presumed to beinvolved by the brick surface condition， as the difference in the polished states of the two bricksurfaces can be visually observed. For other refractory bricks， high thermal conductivity types are also available besides the lowthermal conductivity type， which may need to characterize them separately. In such cases pleaseconsult us as necessary. 7.References None. 京都电子工业株式会社-可睦电子(上海)商贸有限公司电话：021-54488867 电邮： kemu-kem@163.com