Bimetallic thermometer to two different coefficients of linear expansion of the metal combination together, one end fixed, when the temperature changes, the two metal thermal expansion is different, drive the pointer deflection to indicate the temperature, this is the bimetal thermometer, as shown in the figure on the previous page. Temperature measurement range of -80 ~ 500C, it is suitable for industrial precision requirements are not high when the temperature measurement. Bimetal as a temperature sensing element can also be used for automatic temperature control.
Classification
According to the bimetal thermometer pointer disk and the protection of the direction of the connection of the tube can be divided into four types of bimetal thermometers axial type, radial type, 135 ° to the type and universal type.
① axial type bimetal thermometer: pointer disk and protection tube connected vertically.
② radial type bimetal thermometer: the pointer disk and the protection of the parallel connection.
③ 135 ° to the type of bimetallic thermometer: pointer disk and the protection of the tube into 135 ° connection.
④ universal type bimetallic thermometer: the angle of connection between the pointer disk and the protection tube can be adjusted arbitrarily.
Fixed form
In order to adapt to the needs of actual production, the bimetal thermometer has different mounting and fixing forms: movable male threaded pipe connector, movable female threaded pipe connector, fixed threaded connector, ferrule threaded connector, ferrule flange connector and fixed flange.
Model Naming
W S S □ □ □ □ □ □ - Protection form
None - General type
Installation and fixing method W-Protection type
0-No fixing F-Anti-corrosion type
Structure 1-Movable external thread
0-Axial type 2-Movable inner thread
1-Radial type 3-Fixing thread
2-135° type 4-fixed thread
3-Universal 5-Ferrule Threads
Nominal Diameter 6-Ferrule Flange
3-φ60
4-φ100
5-φ125
Sensing element is bimetallic
Metal expansion type
Temperature meter
Characteristics
The advantages of bimetallic thermometer are fast response speed, small size, good linearity, more stable, some foreign products also have high temperature performance.
The size of the thermal potential of the bimetal thermometer is only related to the thermoelectric properties of the hot electrode material and the temperature difference between the two ends.
Using the same kind of homogeneous conductor or semiconductor circuit, will not produce thermal potential.
Thermocouple two contact temperature T, T0, if T = T0, thermocouple thermal potential is zero. The intermediate temperature law lays the foundation for the development of thermocouple indexing table.
If the two conductors A, B, respectively, with the third conductor composed of thermoelectric have a wide range of temperature measurement, long-term use of the physical and chemical properties of the stable
High conductivity, resistance temperature coefficient is small; ※ configuration of the thermopotential sensitivity is high, the thermopotential and the temperature between the linear, easy to copy, simple process, cheap.
Generally speaking, bimetal thermometers are used at low temperatures and thermocouples are used at high temperatures. If the temperature is more than 500 degrees then the resistance value of the bimetal thermometer will be very large, which may affect the measurement results, and even the situation of not being able to come out with the measurement results occurs.
Common Types
There are several types of bimetal thermometers.
Outdoor type, heavy duty
The bimetal thermometer is a kind of on-site testing instrument suitable for measuring low and medium temperatures, and can be directly used to measure the temperature of liquids and gases.
Main technical parameters:
(1) Precision grade: 1.5 grade
(2) Time constant: J<40S
(3) Protection tube pressure resistance: 6.3MP
Electric contact type
Bimetallic thermometer is a kind of field detecting instrument suitable for measuring medium and low temperature, which can be directly used to measure the temperature of liquid and gas.
Main technical parameters
(1) Precision grade: 1.5 grade
(2) Time constant: J<40S
(3) Protective tube pressure: 6.3MPa
(4) Contact capacity: rated power 10VA (non-inductive); maximum voltage: AC 220V, maximum working current: 1A (non-inductive), contact for the upper and lower limits and normally open.
(5) Operating ambient temperature of meter head: -25~55 degrees Celsius
Seismic type
WSSXN series shock-resistant electric contact bimetallic thermometer is a kind of on-site detecting instrument for measuring low and medium temperatures. Can be directly measured in a variety of production processes -80 ℃ ~ +500 ℃ range of liquids, steam and gas media and environmental sites in poor and vibration of the temperature.
The vibration-resistant electric contact bimetal thermometer from the instrument internal filling of vibration-resistant oil, can effectively overcome the mechanical vibration brought about by the pointer jitter. In the design principle and structure with waterproof, corrosion-resistant, vibration-resistant, intuitive, easy to read, non-mercury, durable and so on, widely used in petroleum, chemical industry, machinery, shipbuilding, power generation, textile, printing and dyeing and other industrial and scientific research departments.
Main features:
(1) On-site display of temperature, intuitive and convenient, safe and reliable, long service life;
(2) A variety of structural forms, can meet different requirements, no mercury, easy to read, sturdy and shock-resistant;
(3) Protective tubing for 1Cr18Ni9Ti stainless steel and molybdenum two titanium, pressure, corrosion resistance;
(4) The core-pulling thermometer can not be shut down for a short time to maintain or replace the movement.
Working principle.
Shock-resistant electric contact bimetallic thermometer is based on the bimetallic sheet wound into a circular bending composition. When one end is subjected to thermal expansion, driving the pointer rotation, the work of the instrument will show the corresponding temperature value, and to prevent environmental vibration in the internal bimetal thermometer filled with silicone oil or bimetal thermometer display part and measurement part of the separation to achieve the effect of vibration resistance.
Vibration-resistant bimetal thermometer is divided into two types: integrated vibration-resistant electric contact bimetal thermometer and separated vibration-resistant electric contact bimetal thermometer.
Main technical parameters:
(1) Implementation standard: JB/T8803-1998 GB3836-83
(2) Scale disk nominal diameter: 60 100 150
(3) Precision level: (1.0), 1.5
(4) Thermal response time: ≤ 40S
(5) Protection grade: IP55
(6) Angular adjustment error: Angular adjustment error should not exceed 1.0% of its range
(7) Return difference: the return difference should not be greater than the absolute value of the basic error limit
(8) Repeatability: Repeatability limit range should be no more than 1/2 of the absolute value of the basic error limit.
Universal type
Main technical parameters:
(1) Scale disk nominal diameter: 100;150
(2) Precision grade: 1.0, 1.5
(3) Connection size: M20x1.5, NPT1/2
(4) Thermal response time: ≤40s
(5) Protection grade: IP55
Integrated Bimetal Thermometer
Overview of Bimetal Thermometer
Integrated bimetal thermometer is a combination of RTD or thermocouple signal transmission function and bimetal thermometer on-site indication function, which can meet the needs of on-site temperature measurement, but also meet the needs of long-distance transmission, long-distance transmission of bimetal thermometers can be directly measured in a variety of production processes within the range of -40 ~ +600 ° C liquids, vapors and gases, as well as temperature measurement of the surface of solids.
Performance characteristics
1, with a small temperature probe, high sensitivity, linear scale, long life and other characteristics.
2, with remote output resistance signal (PT100), shock resistance, corrosion resistance and high-power switch signal and other functions.
3、The structure form is the same with the international similar products, can replace the import.
Technical parameters
1、Temperature measurement range -40～600℃.
2、Ambient temperature -10～55℃
3、Relative humidity ≤95%.
4、Accuracy level 1.5
5、Time constant ≤60S
6、Probe pressure ≤6Mpa
7、Probe diameter: φ8-10mm, movable external thread: M27*2
8、Resistance thermistor PT100 (single, double output) or 4-20mA current output
9、Protection level: IP55
Heat Sleeve Type
Heat sleeve type bimetallic thermometer can be matched with various types of mounting sleeves to meet the requirements of different pressure levels. Can be directly measured in a variety of production processes -80-+500 ℃ range of liquid, steam and gas media and solid surface temperature measurement. Widely used in petroleum, chemical, metallurgy, textile, food and other industries.
