Instrument heating and insulation

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Due to the wide variety of materials tested by the instrument detection system, and the varying physical properties such as their condensation temperatures, phenomena such as freezing, condensation, and crystal deposition can occur under the influence of the surrounding ambient temperature. As specified in the design requirements, the temperature of the material within the instrument piping must be maintained between 20-80°C, while at the operating ambient temperature, the temperature inside the instrument insulation box should remain between 15-20°C. Since at such temperatures, normal transmission of pulse signals by the material within the instrument pipelines is generally still possible, it is necessary to address the issues of freezing and overheating in order to ensure the accurate and reliable operation of the instrument detection system; this involves providing heat tracing and insulation protection for the instrument pipelines and equipment. 1. Insulation type: Depending on the object to be insulated, it can be divided into two types, namely heat-tracing insulation and thermal insulation. ⑴ Heating and insulation: When the material being measured is affected by the ambient temperature, phenomena such as freezing, condensation, crystallization, and precipitation can occur; therefore, heating and insulation measures are necessary for the instruments and their piping. Depending on the heat source used for heating, there are 3 types of heat tracing. ① Steam tracing: The use of low-pressure steam is the most common form of tracing and insulation in engineering projects. ② Hot water tracing should not be used with testing systems designed for steam tracing, nor in situations where there is no steam heat source available. ③ Electrical heating is used in situations where remote and automatic control is required, where high cleanliness standards apply, or when there are no other heat sources available. With the advancement of electric heating technology, it will become a new generation of insulation method. ⑵Insulation is necessary for instrument detection systems dealing with hot fluids (such as steam, hot water, or other high-temperature materials) and cold fluids (such as liquid ammonia, liquid nitrogen, or other low-temperature fluids). 2. Heat tracing method: The heat tracing methods are divided into heavy heat tracing and light heat tracing. To ensure that the material being measured in the measurement pipelines and instruments remains in a proper operating condition, the appropriate heating method should be determined based on the properties of the material. When measuring materials that are corrosive, thermally sensitive, or prone to decomposition, it is not allowed to have the heat tracing tube in close contact with the instruments and measurement pipes. ①Heavy tracing refers to the situation where the tracing tube is in direct contact with the instruments and measurement pipes. ②Light tracing: Light tracing refers to a situation where the tracing tube does not come into direct contact with the instruments and measurement pipes; instead, an asbestos sheet is placed between them as a separator.