WRNG-440 Flameproof High Temperature and High Pressure Thermocouple Shanghai Automation Instrument Third Factory

1、 Instrument Overview:

WRNG-440High temperature and high pressure thermocoupleSuitable for temperature measurement and control in high-temperature and high-pressure environments in petroleum, chemical and other production processes. It is an indispensable temperature device for refineries, high-pressure polyethylene, and other industries.

2、 Measurement principle:

High temperature and high pressure thermocoupleIt is the welding of two different materials of conductors or semiconductors A and B to form a closed circuit. When there is a temperature difference between the two attachment points 1 and 2 of conductor A and B, an electromotive force will be generated between them, thus forming a large and small current in the circuit. This phenomenon is called the Thermoelectric effect. Thermocouples work by utilizing this effect.

3、 Performance characteristics:

1. High measurement accuracy. Due to the direct contact between the thermocouple and the tested object, it is not affected by the intermediate medium.

2. Wide measurement range. Commonly used thermocouples can be continuously measured from -50 to+1100 ℃, while some special thermocouples can measure temperatures as low as -269 ℃ (such as gold, iron, nickel, and chromium).

3. Simple construction and convenient use. Thermocouples are usually composed of two different types of metal wires, and are not limited by size or beginning. They have a protective sleeve outside, making them very convenient to use.

4、 Technical indicators:

1. Electrical outlet: M20x1.5, NPT1/2;

2. Connection size: M20x1.5, NPT1/2;

3. Protection level: IP65;

4. Explosion proof level: d Å BT4, d Å CT5;

5. Nominal pressure: 15-40MPa.

5、 Types and structure formation of thermocouples:

(1) Types of thermocouples:

Commonly used thermocouples can be divided into two categories: standard thermocouples and non-standard thermocouples. The so-called standard thermocouple refers to a thermocouple that has a national standard that specifies the relationship between its thermal potential and temperature, allowable errors, and a unified standard graduation table. It has accompanying display instruments for selection. Non standardized thermocouples are not as good as standardized thermocouples in terms of usage range or order of magnitude, and generally do not have a unified graduation table. They are mainly used for measurement in certain special occasions. Standard thermocouples are produced according to IEC standards, and the eight standard thermocouples S, R, B, K, N, E, J, and T are uniformly designed thermocouples.

(2) The structural form of the thermocouple requires the following to ensure its reliable and stable operation:

① The welding of the two thermoelectric electrodes that make up the thermocouple must be firm;

② The two thermoelectric electrodes should be well insulated from each other to prevent short circuits;

③ The connection between the compensation wire and the free end of the thermocouple should be convenient and reliable;

④ The protective sleeve should ensure sufficient isolation between the thermoelectric electrode and harmful media.

6、 Installation method:

1. Firstly, the dimensions of the thermocouple flange or threaded thread should be measured, and the flange or threaded base should be machined and matched

2. According to the size of the flange or threaded base, holes should be made on the pipeline that needs to be measured

3. Welding of flange or threaded base: Insert the flange or threaded base into the already opened hole, and weld the flange or threaded base with the measured pipeline

4. Tighten the thermocouple with bolts or thread it into the welded threaded base

5. Connect the junction box of the thermocouple according to the wiring diagram and connect it to the corresponding display instrument on the dial. Note that the junction box should not come into contact with the wall of the measured medium pipeline, ensuring that the temperature inside the junction box does not exceed the range of 100 ℃. The outlet hole of the junction box should prevent short circuits in the wiring terminals due to poor sealing, water vapor, dust, and other deposits.

7、 Material and selection of protective tube:

8、 Selection of casing form:

The flange can be selected in different forms such as 900 (PN15) -2500LB (PN40) RJ.

9、 Flange standard code:

10、 Model and specifications:

Note: 1. Thermocouple level I shall be ordered according to the agreement;

2. Other materials of the protective tube shall be ordered according to the agreement

3. The model 430 is waterproof and the model 440 is explosion-proof.

11、 Selection instructions:

1. Model;

2. Graduation number;

3. Accuracy level;

4. Material and form of protective tube;

5. Flange specifications and forms;

6. Length or insertion depth.