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  • 温度计的内插误差
  • 本站编辑:杭州博阳仪器仪表有限公司发布日期:2019.10.16
由于每种热电阻数量不多,还由于在很长的时间内漂移值不是恒定的,因此,表6的位不是十分精确的.但从这些值可以看出,若采用合适的内插程序,则测量精度可在很长时间内优于0,1K,只需要极少的复检。为了说明用这些较为简单的热电阻可以取得什么样的效果,我们谈一下利用它们传递黑体腔银点分度值的情况。
    如果在将来的温标中热电偶要被光学高温计和电阻温度计取代,那么电阻温度计和光学高温计之间就必须相互传递。电阻温度计用的是立式金属定点炉,而在我们的实验室中,光学高温计用的是卧式黑体炉.我们的实验室一直用一个特殊的钠热管黑体腔为这两种系统进行传递.关于这方面的实验在这次讨论会中有专文详加叙述电阻温度计的插管是卧式放置的,在银点多次使用后它发生形变,因此只有很细的温度计才能插入.将一支Heraeus 2515热电阻按文献(2)叙述的方式安装,在装配过程中进行900℃退火64h,在我们能够得到的温度计中,除这一文以外,其他的都放不进这台装置内.在整个实验期间这支温度计在银点(962℃)共经受了86h,从960℃至室温间共进行了25次循环。
    在银点进行了4次电阻测量。在这4次测盖之间的漂移,用0℃, l00℃和锌点(可能的话)的分度谊来估计;温度计在960℃每经受1h,冰点电阻值升高0,00007欧,每经受1次循环,冰点电阻值升高0,0001欧,由此进行内插。第一次进行黑休测量以后,曾,经出现相当大的不稳定性。除此以外,温度计的其他特性是令人满意的。利用银点的温度来计算某一分度的电阻值,再在下次分度计算出相当于该电阻值的温度,这样计算出来的温度值对于银点温度的偏离,是温度计漂移误差的量度。在960℃9h之后(包括7个循环,未经锌点分度),漂移误差大优为0.088K.两次银点之间的偏离,大多数都小于0.03K。在进行光学高温计比对的时候,我们对漂移作了估计,总误差(温度计的漂移加上银点分度误差)估计小于0.03K.
    要改善这种测摄是有可能的,可以从一批热电阻中选择稳定的,并对测量的具体做法加以改进,由此估计这样测量的内播误差可望达到0,02K.除非能生产出牢靠的标准电阻温度计,否则,要把任何经过改善的温标传递至工作场合时,这0.02K就是极限。

Since the number of heat resistors per type is not large, and because the drift values are not constant for a long period of time, the bit in table 6 is not very accurate. However, it can be seen from these values that if a suitable interpolation procedure is used, The measurement accuracy can be better than 0,1K for a long period of time, and only minimal re-examination is required. To illustrate what can be achieved with these relatively simple thermal resistors, we talk about the use of them to transmit the black cavity silver fraction value.
If the thermocouple is to be replaced by an optical thermometer and a resistance thermometer in a future temperature scale, then the resistance thermometer and the optical thermometer must be transmitted to each other. Resistance thermometers use vertical metal fix-point furnaces, and in our lab, The optical altimeter uses a horizontal black body furnace. Our laboratory has been transmitting these two systems with a special sodium heat tube black body cavity. The experiment in this regard was specifically described in this seminar. The intubation of the resistance thermometer is horizontal. After the silver point is used many times, it deforms, so only a very fine thermometer can be inserted. A Heraeus 2515 thermal resistor is installed in the manner described in document(2) and annealed at 900 °C during the assembly process. 64h, in the thermometer we can get, With the exception of this article, none of the others could be placed in this device. During the entire experiment, the thermometer experienced a total of 86h at the silver point(962 °C) and 25 cycles from 960 °C to room temperature.
Four resistance measurements were performed at the silver point. The drift between these 4 test covers is estimated by the division of 0 °C, 00 °C and zinc points(if possible); For each temperature of 1 H at 960 °C, the resistance value of the freezing point increases by 0.00007 euros. For each cycle experienced, the resistance value of the freezing point increases by 0.0001 euros, thereby being interpolated. After the first black gap measurement, there was considerable instability. In addition to this, the other characteristics of the thermometer are satisfactory. The resistance value of a certain degree is calculated using the temperature of the silver point, and the temperature equivalent to the resistance value is calculated at the next degree. The calculated temperature value is a measure of the thermometer drift error for the deviation of the silver point temperature. After 960 °C 9h(including 7 cycles, without zinc points), the drift error is a large deviation of 0.088K between two silver points, most of which are less than 0.03 K. When the optical thermometer was paired, we estimated the total error(the drift of the thermometer plus the silver fraction error) was estimated to be less than 0.03 K.
It is possible to improve this type of measurement by selecting stability from a batch of thermal resistors and improving the specific measurement practices. It is estimated that the intracast error of such measurement is expected to reach 0,02K unless it can produce a solid standard resistance thermometer, Otherwise, this 0.02 K is the limit when passing any improved temperature scale to the workplace.
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