Fast Response Temperature Sensor With Fixinig Plate

The temperature sensor with fixinig plate (also called O-ring temperature sensor) is composed of a housing 11, an NTC thermistor 12, an encapsulation layer 13, a potting layer 14, and an electronic wire 15. The thermistor leads 121 are soldered to the first end of the two electronic wires 15, and the encapsulating resin is covered on the thermistor 12, its leads 121, and the first end of the electronic wires 15 to form the encapsulating layer 13. The encapsulated thermistor 12 is placed in the housing so that the second end of the electronic wires 15 is exposed, and the encapsulating resin is filled into the housing 11 to form the encapsulating layer 14. The closed end of the housing 11 is at the This temperature sensor with a fixed sheet can be fixed to the measured surface with screws through the mounting holes 112, and heat is transferred from the measured surface to the sensor through the fixed sheet or the bottom surface of the housing.

The defect of this temperature sensor is that in use, the heat is transmitted through the measured surface to the fixed plate or the bottom surface of the shell, and then through the potting layer, encapsulation layer before conduction to the thermistor, the temperature sensing process needs to pass through multiple layers, and the encapsulation resin, potting resin is generally used epoxy resin, phenolic resin, silicone resin, thermal conductive silicone grease and other materials, its thermal conductivity is not high, the thermal conductivity is not good, reducing the temperature sensor Sensitivity, the thermal time constant of this structure of the temperature sensor is generally 10 to 20 seconds, and the response speed is slow.

Therefore,Exsense provides a fast response temperature sensor with a fixed plate.

This temperature sensor, including shell, substrate, thermistor, encapsulation layer, potting layer and two electronic wires; shell is a hollow shell, its bottom surface is provided with a fixed hole, the bottom surface of the shell extends outward to form a fixed plate, and the  fixed plate is provided with a mounting hole; substrate fixed in the hole, the bottom surface of the substrate and the bottom surface of the fixed piece are located on the same side; thermistor fit fixed in the substrate, and respectively with the first end of the two electronic wires The second end of the electronic wire extends outside the shell; the encapsulation layer covers the thermistor and the potting layer is filled inside the shell.

By setting a substrate in the same plane as the fixed sheet, the heat of the measured surface can be directly conducted to the substrate, and at the same time, the thermistor is directly laminated and fixed to the substrate, then the heat of the measured surface can be directly conducted to the thermistor through the substrate, avoiding the defect that the heat of the measured surface needs to pass through the shell, the potting resin and the encapsulation resin before it is transmitted to the thermistor, greatly reducing the thermal time constant and improving the The temperature sensor response speed is greatly reduced, and the temperature sensor is simple and compact, highly reliable and easy to produce.

Table 1 below shows the comparison of the thermal time constant test results of the conventional temperature sensor and the fast response temperature sensor with fixed sheet in Figure 1.

As can be seen, the conventional temperature sensor thermal time constant is generally 10 to 20 seconds, while the fast response temperature sensor with fixed piece only requires 0.4 to 0.5 seconds, which greatly reduces the thermal time constant and improves the temperature sensor response speed.

Table 2 below shows the reliability test results of the temperature sensor of the present invention, the reliability test is specifically 1000 cycles of cold and heat shock, 1000 hours of high temperature aging and high temperature load test.

As can be seen, this temperature sensor after a series of reliability tests, the rate of change within ± 0.3%, indicating that its resistance value stability is good, there will be no drift, sudden change phenomenon, high reliability.

This fast response temperature sensor with fixing plate, when used, screws are inserted into the fixing sheet and screwed into the measured device, so that the fixing sheet is fixed tightly with the measured surface, and by setting a base sheet located in the same plane with the fixing sheet, the heat of the measured surface can be directly conducted to the base sheet, and at the same time, the thermistor is directly attached to the base sheet, so that the heat of the measured surface can be directly conducted to the thermistor through the base sheet, avoiding the It avoids the defects of the existing technology that the heat of the measured surface needs to pass through the shell, potting resin and encapsulating resin before it is transferred to the thermistor, greatly reduces the thermal time constant, improves the response speed of the temperature sensor, and the temperature sensor has a simple and compact structure, is highly reliable, easy to manufacture, and can withstand high temperatures up to 300℃.