With NTC thermal chip as the core electronic component, the thermistor element and NTC temperature sensor composed of different packaging forms are widely used in various temperature detection, temperature compensation and temperature control circuits. It plays a central role in converting temperature variables into desired electronic signals in electrical circuits.
With the development of electronic technology, various electronics are further multi-functional and intelligent, and the application of NTC thermal chips in various occasions requiring temperature detection, control, compensation, etc. has gradually increased. At the same time, higher temperature sensor structures are proposed. Requirements, in order to achieve high precision, high sensitivity, high reliability, and rapid detection, the structural design of the temperature sensor must meet the structural requirements of the object to be tested.
However, the existing tube body temperature sensor is generally contacted by its shrapnel convex surface and the circular arc surface of the tube body, resulting in a relatively small contact area between the two, and the heat transfer makes the heat very slow, resulting in a relatively slow temperature sensing speed of the temperature sensor. Slow, it takes a long time for the temperature to transfer from the tube body to the core thermal chip inside the temperature sensor. The thermal time constant is generally 10-20 seconds. This reaction speed cannot meet the high sensitivity requirements for temperature detection, and there will be temperature measurement. Not allowed phenomenon.
In addition, the shell structure of the existing pipe body temperature sensor can only be adapted to measure the temperature of a pipe of a single size, and cannot be used for pipes of various sizes, and its versatility is poor. The temperature sensor needs to be customized for a specific pipe, and its installation is complicated and inconvenient. operate.
Based on this, a universal pipe surface temperature sensor is provided, which has the advantages of convenient use, strong versatility, fast response speed, sensitive detection and high mechanical strength.
The sensor uses conventional structural clips and shrapnel as the shell, and at least one NTC thermistor is placed in the cavity between the clip and the shrapnel; by setting the adjustable clip, the temperature sensor can be clamped in a variety of different pipe diameters. , the operation is convenient and fast, and the versatility is strong; and when the shrapnel is pressed against the tube body to be tested, it can deform to match the outer wall of the tube to be tested. It is closely fitted and has a large contact area to achieve full contact. Therefore, the thermistor in contact with the shrapnel can quickly receive the temperature from the fluid in the tube under test, and its response speed is very fast, which can achieve highly sensitive detection. The thermal time constant of the high-sensitivity temperature sensor is 2 to 3 seconds, which is only one-fifth of the existing sensor, and its heat conduction speed is much higher than that of the existing temperature sensor; The temperature sensor has high mechanical strength.
The production method of the universal pipe surface temperature measurement temperature sensor is as follows:
(1) Make two clips 10 and springs 11 respectively, then assemble the clip 1 with the rotating shaft 13, and make the shrapnel 2;
(2) At least one thermistor 3 is bonded and encapsulated on the elastic sheet 2 with the encapsulation material 4, and one end of the electronic wire 5 is connected to the thermistor 3, and the electronic wire 5 is connected to the thermal resistor 3 with an insulating sleeve 50. The connection of the varistor 3 is insulated and protected, and then the other end of the electronic wire 5 is connected to the connector 6 through the small hole opened on the clip 10;
(3) Connect the elastic piece 2 of the bonded thermistor 3 to the clip 10, so that the thermistor 3 is placed in the cavity formed between the elastic piece 2 and the clip 10;
(4) curing and condensing the encapsulant 4 in the encapsulated temperature sensor to complete the production;
(5) The resistance value test and the insulation withstand voltage test are carried out on the fabricated temperature sensor.
Test the thermal time constant of the general-purpose tube body surface temperature measurement temperature sensor of the present invention and the temperature sensor product of the existing tube body temperature measurement respectively, and the test comparison results are shown in Table 1 below:
It can be seen from the above table that the general-purpose tube surface temperature sensor has a faster response speed and higher sensitivity, and its thermal time constant can reach only 1/5 of the existing temperature sensor for tube temperature measurement, and the minimum is only 2 second.
Miss Lei
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