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  • 温度计探头的设计
  • 本站编辑:杭州博阳仪器仪表有限公司发布日期:2020.01.05
一般的温度计用户都希望探头响应快,结构牢固,精度高。然而,响应快速的探头往往是不牢固的,而结构牢固的探头有时其精度又有问题,例如满足不了插入深度的规定等等。此外,探头本身的结构会导致各种误差,比如绝缘电阻低,产生寄生电势,套管或引线焊点受到腐蚀,焊点接触电阻和插头接触电阻发生变化等。
    某些生产方法在消除由探头本身引起的误差方面取得了很大进展。多股引线可能因其中几股折断造成电阻值改变,而用户又不易觉察出这种改变.单芯引线要么是好的,要么是坏的,不会出现使人吃不准的“灰色地区”。引线与元件的焊接月电容放电式点焊。为防止焊点氧化,焊接时用情性气体保护.对每种元件都详细地规定了焊接参数,如焊接电压、焊接压力、电极形式等,特别是要规定焊接脉冲宽度,因为每个厂家都用不同类型、不同直径的引线。对于某些金同相互焊接,焊接脉冲宽度十分重要,但这个参数在一般点焊机上是不能调整的。
    在正常情况下,元件的绝缘电阻是很高的,但在高温时它按指数函数下降。此外,使用玻瑞粘结剂来粘结元件也会降低绝缘电阻,因为在制造过程中如果硅徽盐玻璃没有经过很好地烘烤,这类玻璃就具有吸湿性,从高沮冷却时会吸收大量水份。

The general thermometer users are expected to probe fast response, solid structure, high accuracy. However, fast-response probes are often unstable, while well-structured probes sometimes have problems with accuracy, such as not meeting insertion depth requirements. In addition, the structure of the probe itself can lead to various errors, such as low insulation resistance, generating parasitic potential, casing or lead solder joint corrosion, solder joint contact resistance and plug contact resistance changes. Some production methods have made great progress in eliminating errors caused by the probes themselves. Multiple leads may change resistance due to several breaks, which are not easily detectable by the user. Single-core leads are either good or bad and there is no "grey area" to be uncertain about. Capacitor discharge spot welding of lead and component. In order to prevent the oxidation of solder joints, welding with gas protection. Welding parameters, such as welding voltage, welding pressure and electrode type, are specified in detail for each component, especially for welding pulse width, because each manufacturer uses different type and diameter of lead wire. The pulse width is very important for some metal-to-metal welding, but this parameter can not be adjusted on general spot welding machine. Normally, the insulation resistance of the element is very high, but at high temperatures it decreases exponentially. In addition, the use of Boric binder to bond components also reduces insulation resistance, because if the silicate glass is not well baked during the manufacturing process, the glass is hygroscopic and absorbs a lot of water when cooled from high pressure.
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