Thermal resistance is the most commonly used temperature detector in low and medium temperature area.

Its main characteristic is high precision and stable performance.

Among them, the measurement accuracy of platinum thermal resistance is the highest. It is not only widely used in industrial temperature measurement, but also made into a standard benchmark instrument.

1.

Thermistor temperature measuring principle and material

Thermal resistance temperature measurement is based on the property that the resistance value of metal conductor increases with the increase of temperature.

Most thermal resistors are made of pure metal materials, and currently the most widely used materials are platinum and copper. In addition, thermal resistors are now being manufactured from materials such as dian, nickel, manganese and rhodium.

2.

The structure of the thermal resistance

(1) proficient in the structure and characteristics of thermistor temperature sensing elements (resistors) commonly used in thermistor industry.

In temperature measurement principle of thermal resistance, measured the change in temperature is directly measured by the change of the thermal resistance tolerance, therefore, the wires of a thermal resistance and so on all kinds of wire resistance change will affect temperature measurement.

In order to eliminate the influence of lead resistance, three - wire or four - wire system is adopted.

(2) armoring thermal resistance Armored thermal resistance is by thermal element (resistance), wire, insulation materials, stainless steel casing combination solid body, its diameter is generally from 2 to 8 mm, minimum of phi mm.

Compared with the conventional thermal resistance, it has the following advantages: small volume, no air gap in the interior, low measurement lag in thermal inertia;

Chemical compounds have good mechanical properties, vibration resistance and shock resistance.

Press can bend, easy to install and long service life.

(3) the thermistor temperature sensing element at the thermal resistance end face of the end face is made of specially treated resistance wire material and is glued to the end face of the thermometer.

Compared with the general axial thermal resistance, it can reflect the actual temperature of the measured end face more accurately and quickly, and is suitable for measuring the end face temperature of the bearing bush and other machine parts.

(4) the flameproof thermal resistance flameproof thermal resistance through the special structure of the junction box, its shell internal explosive mixed gas by affected by sparks or electric arc explosion limit within the junction box, that wouldn't make production field explosion.

Flameproof thermal resistance can be used to measure the temperature of explosive dangerous places in Bla~B3c zones.

3.

Composition of thermal resistance temperature measurement system

Thermal resistance temperature measurement system generally consists of thermal resistance, connecting wires and display instruments.

Two points must be noted:

The fractional number of the thermal resistance and the display instrument must be the same

In order to eliminate the influence of the resistance change of the connecting wire, the three-wire method must be adopted.

(2) armoring thermal resistance Armored thermal resistance is by thermal element (resistance), wire, insulation materials, stainless steel casing combination solid body, its diameter is generally from 2 to 8 mm, minimum of phi mm.

Compared with the conventional thermal resistance, it has the following advantages: small volume, no air gap in the interior, low measurement lag in thermal inertia;

Chemical compounds have good mechanical properties, vibration resistance and shock resistance.

Press can bend, easy to install and long service life.

(3) the thermistor temperature sensing element at the thermal resistance end face of the end face is made of specially treated resistance wire material and is glued to the end face of the thermometer.

Compared with the general axial thermal resistance, it can reflect the actual temperature of the measured end face more accurately and quickly, and is suitable for measuring the end face temperature of the bearing bush and other machine parts.

(4) the flameproof thermal resistance flameproof thermal resistance passes through the junction box of special structure, and the explosive mixture gas inside its shell is affected by sparks or arc, etc.

It is necessary to change the length of the resistance wire and affect the resistance value of the resistance. Therefore, it is good to replace the new resistance.