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  • 双金属温度计的安装要求
  • 本站编辑:杭州博阳仪器仪表有限公司发布日期:2019.07.13
对双金属温度计的安装,应注意有利于测温准确,安全可考及维修方便,而且不影响设备运行和生产操作,要满足以上要求,在选择对热电阻的安装部位和插入深度时要注意以下几点:

(1)为了使热电阻的测量端与被测介质之间有充分的热交换,应合理选择测点位置,尽量避免在阀门,弯头及管道和设备的死角附近装设热电阻。

(2)带有保护套管的热电阻有传热和散热损失,为了减少测量误差,热电偶和热电阻应该有足够的插入深度:

a、对于测量管道中心流体温度的热电阻,一般都应将其测量端插入到管道中心处(垂直安装或倾斜安装)。如被测流体的管道直径是200毫米,那热电阻插入深度应选择100毫米;

b、对于高温高压和高速流体的温度测量(如主蒸汽温度),为了减小保护套对流体的阻力和防止保护套在流体作用下发生断裂,可采取保护管浅插方式或采用热套式热电阻。浅插式的热电阻保护套管,其插入主蒸汽管道的深度应不小于75mm;热套式热电阻的标准插入深度为100mm;

c、假如需要测量是烟道内烟气的温度,尽管烟道直径为4m,热电阻插入深度1 m即可;

d、当测量原件插入深度超过1m时,应尽可能垂直安装,或加装支撑架和保护套管。

For the installation of bimetallic thermometers, attention should be paid to being conducive to accurate temperature measurement, safe and convenient for examination and maintenance, and it does not affect the operation of equipment and production operations. It is necessary to meet the above requirements. The following points should be noted when selecting the installation location and insertion depth of the thermal resistor:
(1) In order to provide adequate thermal exchange between the measuring end of the thermal resistance and the medium to be measured, the position of the measuring point should be reasonably selected and the installation of the thermal resistance near the valve, the bend and the dead corner of the pipe and equipment should be avoided as far as possible.
(2) Thermothermal resistors with protective casing have heat transfer and heat dissipation losses. To reduce measurement errors, thermocouples and thermal resistors should have sufficient insertion depth:
A) For thermal resistors measuring fluid temperature in the center of a pipeline, the measuring end should generally be inserted into the center of the pipeline(vertical or inclined installation). If the diameter of the pipeline of the measured fluid is 200 mm, the thermistor insertion depth should be 100 mm;
B) For temperature measurements of high temperature, high pressure and high speed fluids(such as the main steam temperature), in order to reduce the resistance of the protective cover to the fluid and prevent the protective cover from breaking under the action of the fluid, the protective tube may be inserted shallowly or the thermal resistance of the heat cover is used. Shallow insert heat resistance protection sleeve, the depth of which shall not be less than 75mm into the main steam pipeline; The standard insertion depth of the heat resistance is 100mm;
C, if it is necessary to measure the temperature of the flue gas in the flue, although the flue diameter is 4m, the thermal resistance can be inserted at a depth of 1 m;
D) When the depth of insertion of the original measurement exceeds 1M, it shall be installed as vertically as possible or with a support frame and protective sleeve.

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