There are numerous thermocouple types which are used to measure temperature in experimental fire environments including bare bead, plate, sheathed (grounded and ungrounded) and aspirated thermocouples (suction pyrometers). Furnaces used to test fire resistive construction, as specified in the Standards ANSI/UL 263, ASTM E119 and NFPA 251 employ sheathed, ungrounded thermocouples to measure gas temperatures, while room fire experiments, such as ASTM E603-01, employ bare bead and aspirated thermocouples to measure hot gas temperature layers. Shielded, aspirated thermocouples are quite inexpensive and easy to make, however, the suction needed to create velocities in excess of 10 m/s at the tip is quite a difficult challenge. A commonly used method to create suction includes multiple gas traps to cool and dehumidify the hot gas before passing through a pump rated for high temperatures. This method can be costly, time consuming to maintain and cannot operate for multiple hours at high temperature without damaging the pump. An investigation has been undertaken to determine a cost effective method to measure gas temperatures in fire test furnaces for long durations at high temperatures. A comparison of bear bead, plate and double shielded, aspirated thermocouples will be presented. A low cost, durable aspirated thermocouple will be shown to continuously endure temperatures in excess of 1040 °C for multiple hours.
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机译：有许多热电偶类型，用于测量实验防火环境中的温度，包括裸珠，板，护套（接地和未接地）和吸气热电偶（吸气仪）。用于测试防火结构的炉子，如标准ANSI / UL 263，ASTM E119和NFPA 251采用护套，未接地的热电偶测量气体温度，而房间消防实验，如ASTM E603-01，使用裸露的珠子并吸入热电偶测量热气体温度层。屏蔽的吸气热电偶相当便宜且易于制造，但是，在尖端产生超过10米/秒的速度所需的抽吸是非常困难的挑战。一种常用的制作方法包括多种气体疏水阀，以冷却和除湿热气体，然后通过泵的高温。该方法可以是昂贵的，保持耗时的时间，在高温下不能在不损坏泵的情况下在高温下运行多小时。已经进行了调查，以确定在高温下测量火试验炉中的气温的成本有效的方法。将呈现熊珠，板和双屏蔽，吸气热电偶的比较。低成本，耐用的吸气热电偶将显示在多小时内连续待遇超过1040℃的温度。
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