Bimetallic thermometer (hereinafter referred to as TB/BT) can be used to measure the temperature of a medium in the range from -60°C to +500°C, and the state of aggregation of the measured medium can be almost any:
— liquid: non-aggressive (water) and moderately aggressive (when using a thermal balloon or a stainless steel protective sleeve);
— solid: surface, for clamping versions (pipe TB/BT) or granular medium (needle TB/BT);
— gas: gaseous media and gas mixtures(air, natural or welding gas);
— steam: water or any other non-aggressive steam in relation to the materials of the thermal cylinder and the protective sleeve.
The versatility of TB/BT bimetallic thermometers, the simplicity of their design, relative reliability and low cost explain the breadth of their application: from industrial installations increased reliability (in the UAE) before being used in everyday life as room or bath thermometers.
Design and principle of operation of the TB/BT bimetallic thermometer
Bimetal thermometer TB/BT usually has a round (less often semicircular or square) body, where a dial (scale) and a kinematic mechanism with a pointer are located, connected and a bimetallic temperature-sensitive element in a protective tube (thermal bulb), which reacts to changes in temperature, which is reflected with some inertia in the form of arrow readings .
Operating principle The TB/BT bimetallic thermometer is based on elastic deformation that occurs under the influence of the temperature of two metal plates firmly connected to each other, which have different temperature coefficients of linear expansion. In this case, the bimetallic strip bends (twists) towards the material, the coefficient of linear expansion of which is less. As a result of such deformation, with the help of a kinematic unit, the bending is converted into rotational movement arrow, which, in turn, shows on the thermometer scale the temperature value of the measured medium - Tis.
The disadvantages of bimetallic thermometers TB/BT, relative to liquid glass thermometers TTZh (alcohol) and TTP (mercury), are greater inertia (time spent on warming up the thermal bulb and protective sleeve) and several times higher cost (due to the relative complexity of the design). But these shortcomings are fully compensated by their structural strength, vibration resistance and clarity of indications.
Classification of types of bimetallic thermometers BT/TB of industrial designs
According to the location of the thermal cylinder:
— Radial (thermal bulb radially from below - the dial axis is located perpendicularly at an angle of 90 degrees relative to the axis of the thermal bulb);
— Axial-axial (the thermal bulb is behind the axis (English-axis), the axis of the dial and the thermal bulb are the same (coaxial));
— Tilt-and-turn (universal radial-axial, having a rotating mechanism).
Depending on the type of thermal cylinder, the following types are possible:
— Pipe thermometers, which measure the temperature on the surface of pipes in heating systems(the thermal cylinder is built into the housing, which is pressed against the pipe by a spring);
— Needle thermometers that measure temperature by immersing a special needle-probe into the measurement medium.
Read more about the brands supplied of TB/BT bimetallic thermometers, as well as their technical specifications, selection principles (see how to choose, order and buy TB/BT inexpensively), areas of application, prices (see price list), stock availability or production times, see below.
TB-63, -80, -100 - indicating, axial and radial, chrome steel body 63/80/100mm, L submersible. 50/100/60mm, class.t. 1/1.5/2.5, Di -35…+600°С, scale value 0.5/1.0/2.0/5.0/10.0 °С, fitting thread M20x1, 5 or G1/2 |
TBT-63 - pipe indicating, D 63mm, pipe mounting on a spring, Di 0...+120/0...+150ºС, scale d.f. 1; 2ºС, class 2.5, body - steel |
Bimetallic thermometers TB-ros: thermal bulb axial (rear, end-T) or radial-R (bottom), body diameter 60, 80, 100, 150 mm, accuracy class 2.5-1.5%, 12 ranges from -50 to +600С, Тos -40+60С, L rod from 46 to 300mm (stainless, D=8mm) complete with a brass protective sleeve (fitting G1/2 or M20x1.5), optionally equipped with a flange or sleeve made of stainless steel . steel. |
TBI-25, -40 - needle, axial, stainless steel body and probe, IP65, D 25.40mm, L probe up to 250mm, Di -40...+400ºС, class t.2.5, Tos -55...+70ºС |
Axial thermal cylinder (rear, end-T), body diameter 63, 80, 100, 150 mm, class. t. 1.5-2.5%, 10 ranges from -40 to +450°C, IP43, working pressure 2.5;10;25 MPa, Тos -10+60°С, L rod from 46 to 300 mm complete with a brass protective sleeve (fitting G1/2 or M20x1.5), body - corrosion-resistant steel |
DMT-05080 - thermomanometer, D=80mm, axial O/radial R fitting, class 2.5%, DiT 0...+120°C; 0…+150°С, DiP 0…0.4; 0.6; 1; 1.6; 2.5; 4 MPa, Тos -40+70°С, IP53 |
Thermal cylinder axial (rear, end-T) or radial-R (bottom) threadless: body diameter 63, 100, 160 mm, class. t. 1.5-2.5%, 10 ranges from -20 to +500 °C, degree of protection IP51, climatic version U1, Tos -60+60С, L rod from 50 to 800 mm, fitting Ø9mm, complete with a brass protective sleeve, body - galvanized steel |
Indicating bimetallic thermometers TB-1, TB-2, TB-3: for liquid and gaseous media, general industrial, for ships and for nuclear power plants, thermal bulb axial (rear, end-T) or radial-R (bottom) 6-10 mm, case diameter 60, 100, 160 mm, class. t. 1.5-2.5%, 1.0% (on request), 15 ranges from -20 to +400 °C, degree of protection IP54, climatic UHL version 2, OM5, Тos -60+50С, L rod from 80 to 315 mm, pressure of the measured medium 64-250, vibration resistance from 5 to 100 Hz. |
bimetallic electric contact thermometer TB-E: thermal cylinder axial-T (rear, end) or radial-R (bottom), body diameter 100, 150 mm, class. t. 1%, ranges T= -50…+600С, Тos -40+60С, L rod =35…1000mm (stainless, D=8mm), fitting G1/2 or M20x1.5, contacts with magnetic preload, material - stainless steel. |
thermomanometer (pressure gauge with thermometer) - D=80, 100mm; class 2.5%; DiT 0…+120°С, 0…+150°С; DiP 0…0.25; 0.4; 0.6; 1; 1.6; 2.5 MPa; Tos -50+60°С; connection thread G½; IP42 |
corrosion-resistant axial thermometer - T (rear, end), body diameter 100, 150 mm, class. t. 1.5%, 1%, ranges T= -30...+450С, Тos -60+60С, L rod =46...300mm, fitting G1/2, IP 54, SE - bimetallic spiral, material - stainless steel. |
BT-32/52-211 bimetallic radial thermometers: D=63, 100mm, class. t. 2.5%, 1.5%, ranges T= -30...+450ºС, Тos -10+60ºС, L rod = 46...300mm, fitting G1/2, 20x1.5, IP 43, SE - bimetallic spiral , material - corrosion-resistant steel. |
Thermal cylinder axial -T or radial - R threadless, corrosion-resistant: body diameter 63, 100, 160 mm, class. t. 1.5-2.5%, 10 ranges from -20 to +500 °C, degree of protection IP65, climatic version UHL1, Тos -60+60С, L rod from 50 to 800 mm, fitting Ø9mm, complete with protective sleeve made of stainless steel, housing made of stainless steel |
Thermal cylinder is tilt-and-turn (universal fitting arrangement), corrosion-resistant: body diameter 100, 160 mm; class t. 1.5%, 1%; 11 ranges from -20 to +500 °C; degree of protection IP65; climatic version UHL1; Tos -60+60С; L rod from 50 to 800 mm; fitting Ø8mm; thread G½, M20x1.5, ½NPT; body - stainless steel |
Axial thermometer - T or radial - P, special for ventilation and air conditioning: case diameter 63, 100, 160 mm, class. t. 1.5-2.5%, 5 ranges from -50 to +120 °C, degree of protection IP51, climatic version U2, Тos -60+60С, L rod from 50 to 800 mm, fitting Ø9mm brass, included with flange for mounting on 3 holes, body - galvanized steel. Thermometer axial - T or radial - P, general technical: D: 63, 100 mm, class. t. 1.5-2.5%, CI: from -40 to +450 °C, degree of protection IP54, climatic version UHL1, Тos -70+60С, L sleeves from 46, 64,100 mm - Ø9mm copper alloy, sleeve thread G½, body - corrosion-resistant steel. |
Options, additional equipment and accessories for TB/BT thermometers
— Protective sleeve made of stainless steel (instead of the brass ones usually included in the kit).
— End flange (for thin-walled and without pressure systems), the material is brass.
— Straight mounting boss (welded adapter for thick-walled pressure systems for welding).
— Full bore ball valve (not recommended, since it is more correct to install it in a protective sleeve).
— Gaskets/seals (copper, fluoroplastic, paranitic, rubber, etc., depending on pressure and temperature).
— Critical temperature indicator (red arrow).
— Heat transfer fluid or lubricant (gel) to ensure heat transfer from the sleeve to the thermal cylinder.
— Spare parts and accessories - spare parts and accessories (mechanisms, hands, dial/scales, etc.).
Brands of supplied bimetallic (mechanical) indicating thermometers
This section presents bimetallic mechanical thermometers showing TB (TB1, TB2, TB3, TB4, TB5), BT (BT111, BT211, BT220), TBP (TBP-63, TBP-100, TBP-160), household bimetallic thermometers, protective sleeves, etc.
TB-63, -80, -100, -150-T(R)— bimetallic thermometers (T=-50...+600С, case diameter TB-63, 80, 100, 150 mm, used - axial (rear, end - “T”) or radial (“R”, bottom) location of the thermocylinder, accuracy class 1.5; 2.5%, sleeve thread G1/2, M20x1.5 (brass), rod length (thermocylinder): 35, 46, 64, 100, 150, 200, 250, 300, 350 mm, diameter 8 mm ).
TB-1— bimetallic indicating thermometer (T=-50...+400С, diameter 60mm, axial or radial (TB-1R) location of the thermocylinder, accuracy class 1.5; 2.5%, thread M16, M18, M20, M27) .
TB-2— bimetallic indicating thermometer (diameter 100 mm, available with axial or radial (TB-2R) location of the thermocylinder, accuracy class 1.5; 2.5%, thread M16, M18, M20, M27).
TB-3(-4, -5)— bimetallic indicating thermometer (permissible operating pressure up to 6 MPa; including aggressive media; case diameter 80, 100, 160 mm).
BT-111(-211, -220 (corrosion-resistant))— bimetallic indicating thermometers (T=-40+450C, body diameter 63mm (Class 2.5%), 80, 100, 150mm (Class 1.5%); radial or axial connection, sleeve connecting thread — G1/2 (basic version)).
TBP— bimetallic indicating thermometer (T=-20+400С, case diameter TBP63 – 63mm, TBP100 – 100mm, TBP160 – 160mm; fitting location: central-axial (T) or radial (R) - corrosion-resistant version possible, accuracy class 2.5 %, connecting thread of the sleeve - G1/2 (basic version)).
Protective sleeves (up to 25MPa (250kgf/cm2)).
Bimetal thermometers. household(room, office, window, bath).
It is also possible to supply other grades of technical and special bimetals. thermometers.
Bimetallic thermometers are used for measuring the temperature of liquids and gases, as well as granular and viscous media. The bimetallic thermometer is intended for measuring the temperature of liquids and gases in heating and sanitary installations, in air conditioning and ventilation systems. A bimetallic spring is used as a sensing element.
General technical thermometers (axial connection)
Bimetallic thermometers are used for measuring the temperature of liquids and gases, as well as granular and viscous media.
The bimetallic thermometer is intended for measuring the temperature of liquids and gases in heating and sanitary installations, in air conditioning and ventilation systems.
The operating principle of BT thermometers is based on the dependence of the deformation of the sensing element on the measured temperature.
Scope of application: air conditioning systems, heat supply, water supply. When measuring temperature aggressive environments It is recommended to equip the thermometer with a stainless steel sleeve.
General technical thermometers (radial connection)
The radial bimetallic thermometer is designed for measuring the temperature of liquids, steam and gases in heating and sanitary installations, in air conditioning and ventilation systems. The operating principle of BT thermometers is based on the dependence of the deformation of the sensing element on the measured temperature.
A bimetallic spring is used as a sensing element. A bimetallic spring is made of two firmly connected metal plates that have different temperature coefficients of linear expansion.
The thermometer body is made of corrosion-resistant steel, the stem is made of stainless steel.
Scope of application: air conditioning systems, heat supply, water supply.
When measuring the temperature of aggressive media, it is recommended to equip the thermometer with a stainless steel sleeve.
Corrosion-resistant thermometers (axial connection)
Corrosion-resistant thermometer with axial connection is designed for measuring the temperature of aggressive liquids and gases. The operating principle of BT thermometers is based on the dependence of the deformation of the sensing element on the measured temperature. A bimetallic spring is used as a sensing element. A bimetallic spring is made of two firmly connected metal plates that have different temperature coefficients of linear expansion.
Scope of application:
Corrosion-resistant thermometers (radial connection)
Corrosion-resistant thermometer with radial connection is designed for measuring the temperature of aggressive liquids and gases.
The operating principle of BT thermometers is based on the dependence of the deformation of the sensing element on the measured temperature. A bimetallic spring is used as a sensing element. A bimetallic spring is made of two firmly connected metal plates that have different temperature coefficients of linear expansion.
The body and stem of the corrosion-resistant thermometer are made of stainless steel. The thermometer can be equipped with a stainless steel sleeve.
Scope of application: chemical industry, petrochemical industry, mechanical engineering.
Corrosion-resistant thermometers (universal connection)
Corrosion-resistant thermometer with a universal (swing-out housing) connection is designed for measuring the temperature of aggressive liquids and gases.
The operating principle of BT thermometers is based on the dependence of the deformation of the sensing element on the measured temperature.
The body and stem of the corrosion-resistant thermometer are made of stainless steel. The thermometer can be equipped with a stainless steel sleeve.
Scope of application: chemical industry, petrochemical industry, mechanical engineering.
An indicating thermometer is a device for measuring temperature at various industrial enterprises. A bimetallic thermometer (BT thermometer) refers to technical instruments designed for measuring the temperature of liquids and gases in heating and sanitary installations, in air conditioning and ventilation systems, as well as for measuring the temperature of granular and viscous media in the food industry.
Operating principle technical thermometer is based on the dependence of the deformation of the sensing element (bimetallic spring) on the measured temperature. The spring is made of two firmly connected metal plates, which have different temperature coefficients of linear expansion. When the temperature changes, the spring bends and rotates the thermometer needle. One end of the bimetallic spring is fixed inside the rod, and an arrow is attached to the other (except contact thermometers with a spring for mounting on a pipe, in which the bimetallic spring is wound around the axis of the contact element, and the arrow is fixed directly to the bimetal).
Depending on the type of connection of the rod to the body, BT thermometers are divided into rear (axial) and radial. The device body is made of chrome or stainless steel. Rod material: brass or stainless steel.
Modifications of thermometers
The BT industrial thermometer can be produced in several modifications, which differ in design and component materials:
- general technical series 211 with a chrome-plated steel body and a stainless steel rod;
- general technical special ones with a galvanized steel body and a spring for mounting on a pipe;
- general technical special ones made of stainless steel and a needle-shaped rod;
- corrosion-resistant 220 series stainless steel.
The bimetallic thermometer is equipped with a brass threaded protective sleeve. The exceptions are technical thermometers BT of corrosion-resistant design (series 220) with a stem, ring and body made of stainless steel, as well as general technical special thermometers (with a measuring element in the form of a needle and contact BT with a spring for mounting on a pipe). The 220 series corrosion-resistant industrial thermometer has a thread on the stem, and a protective sleeve is not included in the standard delivery.
Axial bimetallic thermometerRadial bimetallic thermometer designed for measuring the temperature of liquids and gases in heating and sanitary installations, in air conditioning and ventilation systems. The operating principle of BT thermometers is based on the dependence of the deformation of the sensing element on the measured temperature. A bimetallic spring is used as a sensing element. A bimetallic spring is made of two firmly connected metal plates that have different temperature coefficients of linear expansion. When the temperature changes, the spring bends and rotates the thermometer needle. One end of the spring is fixed inside the rod, and the arrow axis is attached to the other.
Corrosion-resistant thermometer with axial connection
Corrosion-resistant thermometer with radial connection designed for measuring the temperature of aggressive liquids and gases. The operating principle of BT thermometers is based on the dependence of the deformation of the sensing element on the measured temperature. A bimetallic spring is used as a sensing element.
The body and stem of the vibration-resistant thermometer are made of stainless steel. The thermometer can be equipped with a stainless steel sleeve
Corrosion-resistant thermometer with universal (swing-out housing) connection designed for measuring the temperature of aggressive liquids and gases. The operating principle of BT thermometers is based on the dependence of the deformation of the sensing element on the measured temperature. A bimetallic spring is used as a sensing element.
Bimetallic clamp-on thermometer (thermometer with spring) designed to measure pipe surface temperature. The operating principle of BT thermometers is based on the dependence of the deformation of the sensing element on the measured temperature. A bimetallic spring is used as a sensing element. The device body is made of corrosion-resistant steel.
Bimetallic corrosion-resistant thermometer with a needle-shaped stem (immersion thermometer) designed for measuring the temperature of thick, granular and viscous media. The operating principle of BT thermometers is based on the dependence of the deformation of the sensing element on the measured temperature. A bimetallic spring is used as a sensing element. Bimetallic needle thermometers are used in agriculture, construction (including for measuring concrete temperature).
Technical liquid thermometer designed for measuring the temperature of non-aggressive liquid and gaseous media under vibration conditions in various industries within the range from -30 to +600 °C.
Thermometers consist of a capillary tube protected by a glass shell with a reservoir filled with thermometric liquid, a protective housing and a protective sleeve. The thermometer scale is printed on the outer surface of the capillary tube. Upper part The capillary tube (with a scale) is located in the housing, and the lower one (with a reservoir) is in the sleeve.
The body is made of anodized aluminum. The sleeve is made either of brass (for thermometers with upper limit measurements up to 200 °C), either from nickel-plated steel (for thermometers with a measurement range of 0...600 °C), or from stainless steel (on request). Depending on the type of connection, two versions are produced: angular thermometer and straight thermometer.