Heat set of thermocouple is a thermocouple, secondary to measure steam pipeline and the temperature of the boiler. Set of thermocouple minor is to use hot sleeve pipe maintenance, and the galvanic couple core can hasten the way of separation, when using, the user can be heat set of welding or thread fixed on the main equipment, then, the thermocouple screwing in the task. It has the advantage of advances in the task of the maintenance of the pipe pressure and use life, and convenient for thermocouple maintained or changed, the current construction methods are widely used. Heat sleeve tube maintenance using special technology of deep blind hole processing technology, the end wall thickness average without welding, namely the information does not exist in welding stress with the grain growth, make the hot set has high mechanical strength and corrosion resistance. As applied to the thermal set of thermocouple based on the task of pressure, temperature and velocity is different, has several corresponding way of construction and installation, the user can according to the using condition from the choice. At the same time, the product is installed on the transmitter, not only save the compensating conductor, and the temperature transducer signal input 4 ~ 20 ma specifications, can strengthen the resistance to disturb, so has excellent function, there is a general use in industry. But the device in the middle of the details, there are some compare if a little attention to, about the using life of thermocouple and measuring precision is very beneficial. Of thermocouple and thermal resistance of the device, should pay attention to temperature measurement precision and peace can test and convenient maintenance, and operation does not affect the equipment operation and consumption. To meet the above requirements, in the choice of thermocouple and thermal resistance of unit area and pull out the depth to pay more attention to the following: 1, in order to make the measurement end of the thermocouple and thermal resistance and has an abundance of heat exchange between the measured medium, should choose the measuring point position, as far as possible to prevent the valve, elbow and pipe and equipment of corner around furnish the thermocouple or heat resistance. 2, with maintenance of casing with heat transfer and thermal loss, in order to increase the measurement error, thermocouple and thermal resistance should have enough: (pulls depth 1) About measuring pipeline fluid temperature at the centre of the thermocouple, common measurement end should be pulled up to the pipe center ( Vertical device or tilted device) 。 As the current body of pipe diameter is 200 mm, the thermocouple or heat resistance draw depth should choose 100 mm; ( 2) Hot thermocouple about low temperature high pressure and high velocity of temperature measurement, Such as main steam temperature) , in order to reduce the maintenance of fluid resistance and avoid maintenance in the fracture fluid under the action of the attack, the way maintenance tube shallow inserted or use hot thermocouple. Shallow inserted type thermocouple casing maintenance, the pull out the depth of the main steam pipe shall be not less than 75 mm; Heat set of thermocouple specifications pulled up a depth of 100 mm; ( 3) Assume that demand is measuring the temperature of flue gas, while the flue is 4 m in diameter, the thermocouple or heat resistance pull out the depth of 1 m. ( 4) As the hot set of thermocouple measurements beyond the original draw depth of 1 m, what needs to be able to vertical device, or mounted to the support and maintenance of the casing.