Indicating thermometer - a device for measuring temperature in various industrial enterprises. Bimetallic thermometer (BT thermometer) refers to technical instruments designed to measure the temperature of liquids and gases in heating and sanitary installations, air conditioning and ventilation systems, as well as to measure the temperature of bulk and viscous media in the food industry.
The principle of operation of a technical thermometer is based on the dependence of the deformation of the sensitive 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 flexes and rotates the thermometer needle. One end of the bimetallic spring is fixed inside the stem, and an arrow is attached to the other (except for 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 on the bimetal).
Depending on the type of connection of the stem to the body, BT thermometers are divided into rear (axial) and radial. The case of the device is made of chrome-plated or stainless steel. The stem material is brass or stainless steel.
Thermometer modifications
Industrial thermometer BT can be produced in several modifications, which differ in design and materials of components:
- general technical series 211 with a chrome steel body and a stainless steel stem;
- general technical special with a galvanized steel body and a spring for mounting on a pipe;
- general technical special made of stainless steel and a stem in the form of a needle;
- corrosion resistant series 220 stainless steel.
The thermometer bimetallic is completed with a brass protective sleeve with a carving. The exceptions are technical thermometers BT of corrosion-resistant design (series 220) with a stem, ring and case 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 industrial corrosion-resistant thermometer of the 220 series has a thread on the stem, and the protective sleeve is not included in the standard delivery.
A thermometer is a device designed to measure the temperature of a liquid, gaseous or solid medium. The inventor of the first device for measuring temperature is Galileo Galilei. The name of the device from the Greek language is translated as "measure heat." The first prototype of Galileo was significantly different from modern ones. In a more familiar form, the device appeared after more than 200 years, when the Swedish physicist Celsius took up the study of this issue. He developed a system for measuring temperature by dividing the thermometer on a scale from 0 to 100. In honor of the physicist, temperature levels are measured in degrees Celsius.
Varieties according to the principle of action
Although more than 400 years have passed since the invention of the first thermometers, these devices still continue to improve. In this regard, there are all new devices based on previously unused principles of operation.
Now 7 types of thermometers are relevant:
- Liquid.
- Gas.
- Mechanical.
- Electrical.
- Thermoelectric.
- Fiber optic.
- infrared.
liquid
Thermometers are among the very first instruments. They work on the principle of expansion of liquids with a change in temperature. When a liquid is heated, it expands, and when it cools, it contracts. The device itself consists of a very thin glass bulb filled with a liquid substance. The flask is applied to a vertical scale made in the form of a ruler. The temperature of the measured medium is equal to the division on the scale, which is indicated by the liquid level in the flask. These devices are very accurate. Their error is rarely more than 0.1 degrees. In various designs, liquid instruments are capable of measuring temperatures up to +600 degrees. Their disadvantage is that when dropped, the flask can break.
Gas
They work in exactly the same way as liquid ones, only their flasks are filled with an inert gas. Due to the fact that gas is used as a filler, the measuring range is increased. Such a thermometer can show the maximum temperature in the range from +271 to +1000 degrees. These instruments are commonly used to take temperature readings of various hot substances.
Mechanical
The thermometer works on the principle of deformation of a metal spiral. Such devices are equipped with an arrow. They look a bit like an arrow clock. Similar devices are used on the dashboard of cars and various special equipment. The main advantage of mechanical thermometers is their durability. They are not afraid of shaking or bumps, like glass models.
Electrical
The devices operate on the physical principle of changing the resistance level of a conductor at different temperatures. The hotter the metal, the higher its resistance to the transmission of electric current. The sensitivity range of electrothermometers depends on the metal used as a conductor. For copper, it ranges from -50 to +180 degrees. More expensive models on platinum can indicate temperatures from -200 to +750 degrees. Such devices are used as temperature sensors in production and in laboratories.
Thermoelectric
The thermometer has 2 conductors in its design, which measure the temperature according to a physical principle, the so-called Seebeck effect. Such devices have a wide measurement range from -100 to +2500 degrees. The accuracy of thermoelectric devices is about 0.01 degrees. They can be found in industrial production, when it is required to measure high temperatures over 1000 degrees.
fiber optic
Made from fiber optics. These are very sensitive sensors that can measure temperatures up to +400 degrees. At the same time, their error does not exceed 0.1 degrees. At the heart of such a thermometer is a stretched optical fiber, which stretches or contracts when the temperature changes. A beam of light passing through it is refracted, which fixes an optical sensor that compares the refraction with the ambient temperature.
Infrared
The thermometer, or pyrometer, is one of the most recent inventions. They have an upper measurement range from +100 to +3000 degrees. Unlike previous varieties of thermometers, they take readings without direct contact with the measured substance. The device sends an infrared beam to the measured surface and displays its temperature on a small screen. In this case, the accuracy may differ by several degrees. Similar devices are used to measure the heating level of metal blanks that are in the hearth, engine housings, etc. Infrared thermometers are able to show the temperature of an open flame. Similar devices are used in dozens of different areas.
Variety by purpose
Thermometers can be classified into several groups:
- Medical.
- Household for air.
- Kitchen.
- Industrial.
Medical thermometer
Medical thermometers are commonly referred to as thermometers. They have a low measuring range. This is due to the fact that the body temperature of a living person cannot be below +29.5 and above +42 degrees.
Depending on the design, medical thermometers are:
- Glass.
- Digital.
- Pacifier.
- Button.
- Infrared ear.
- Infrared forehead.
glass thermometers are the first to be used for medical purposes. These devices are universal. Usually their flasks are filled with alcohol. Previously, mercury was used for such purposes. Such devices have one big drawback, namely the need for a long wait to display the real body temperature. With axillary performance, the waiting time is at least 5 minutes.
Digital thermometers have a small screen that displays body temperature. They are able to show accurate data 30-60 seconds after the start of the measurement. When the thermometer receives the final temperature, it creates an audible signal, after which it can be removed. These devices can work with an error if they do not fit very tightly to the body. There are cheap models of electronic thermometers that take readings no less than glass ones. However, they do not create a sound signal about the end of the measurement.
thermometers nipples made especially for small children. The device is a pacifier that is inserted into the baby's mouth. Typically, such models after the completion of the measurement give a musical signal. The accuracy of the devices is 0.1 degrees. In the event that the baby begins to breathe through the mouth or cry, the deviation from the actual temperature can be significant. The duration of the measurement is 3-5 minutes.
thermometers buttons are also used for children under the age of three years. In shape, such devices resemble a pushpin, which is placed rectally. These devices take readings quickly, but have low accuracy.
infrared ear The thermometer reads the temperature from the eardrum. Such a device is able to take measurements in just 2-4 seconds. It is also equipped with a digital display and runs on. This device is illuminated to facilitate insertion into the ear canal. The devices are suitable for taking temperature in children over 3 years of age and adults, because babies have a too thin ear canal into which the tip of the thermometer does not fit.
infrared frontal thermometers are simply applied to the forehead. They work on the same principle as the ear. One of the advantages of such devices is that they can also operate contactlessly at a distance of 2.5 cm from the skin. Thus, with their help, you can measure the temperature of the child's body without waking him. The speed of forehead thermometers is a few seconds.
Household for air
Household thermometers are used to measure the air temperature outdoors or indoors. They are usually made of glass and filled with alcohol or mercury. Typically, the range of their measurement in outdoor performance is from -50 to +50 degrees, and in the room from 0 to +50 degrees. Such devices can often be found in the form of interior decorations or a fridge magnet.
kitchen
Kitchen thermometers are designed to measure the temperature of various foods and ingredients. They can be mechanical, electrical or fluid. They are used in cases where it is necessary to strictly control the temperature according to the recipe, for example, when preparing caramel. Typically, these devices come with a sealed storage tube.
Industrial
Industrial thermometers are designed to measure temperature in various systems. Usually they are mechanical type devices with an arrow. They can be seen in the mains of water and gas supply. Industrial models are electrical, infrared, mechanical, etc. They have the widest variety of shapes, sizes and measurement ranges.
This section presents manometric thermometers (gas-THP, condensation (vapor-liquid)-TKP) showing: TGP-100M1, TKP100(100S), TKP60-3M, TKP-60S, etc.
TGP-100-M1- thermometer showing gas (T up to 400C, diameter 100mm, 1; 1.5%, capillary from 1.6 to 25m, bulb 160-400mm).
TKP-100-M1- a thermometer showing condensation (T up to 300C, diameter 100mm, 1; 1.5%, capillary from 1.6 to 25m, bulb 160-400mm).
TKP-60/3M- thermometer manometric showing vibration-resistant (diameter 60mm, 1; 1.5; 2.5%, capillary from 1.6 to 25m, bulb 100, 125mm, vibration resistance 5-700Hz, IP53).
TKP-60/3M2- vibration-resistant manometric thermometer (diameter 60, 100, 160 mm, accuracy class 2.5%, capillary from 1.6 to 16 m, bulb 100 mm).
TKP-60S- thermometer manometric showing condensation (diameter TKP60 - 60mm, capillary from 1.6 to 10m).
TKP-100S- a manometric indicating condensation thermometer (TKP100 diameter - 100mm, capillary from 1.6 to 10m).
It is also possible to supply other brands of manometric indicating condensation and gas thermometers.
Operation of thermometers, in modes with pressures of the measured medium exceeding the norms established for them, is possible only with the use of protective sleeves (up to 25 MPa (250 kgf/cm2)).
Time-tested technologies are used for mechanical temperature measurement. Such as bimetal and manometric measurement principles made of various materials with scale ranges from -100 to +500 °C in various accuracy classes and response times. Options for process connections, diameters and stem lengths allow you to choose the right solution for any application.
WIKA mechanical indicating thermometers, with capillary, provide easy and comfortable handling. All WIKA thermometers can be equipped with a thermowell if required. Various models of thermomanometers are also available for selection - a combined pressure and temperature meter (100.12, MFT, etc.).
WIKA A43 - Bimetal thermometer for heating systems
The bimetal thermometer model A43 has been designed for simple measurements in heating systems.
The design is prefabricated, thanks to which various combinations of body materials, nominal sizes, measuring ranges and stem lengths can be made. This allows you to save the customer's design, without making additional changes.
A thermowell is included as standard with the A43, which allows measurements up to a maximum pressure of 6 bar.
Model A43 is manufactured with accuracy class 2 in accordance with EN 13190, which ensures the required indication accuracy for heating technology.
WIKA 46 - Bimetal thermometer with pocket, range up to +120 °C
The model 46 bimetal thermometer is used primarily in heating, air conditioning and refrigeration systems for monitoring process temperatures.
To measure the temperature, a bimetal thermometer is installed in the process together with a thermowell. On the one hand, this protects the thermometer from damage, and on the other hand, it does not require cleaning the heating system to replace it.
WIKA 50 Bimetal thermometer with pocket, range up to +200 °C
Thermometer, Model 50 is designed for use in heating, air conditioning, ventilation and refrigeration technology, for measuring ranges up to 200 °C. To measure the temperature, a bimetal thermometer is screwed into a protective sleeve and placed into the process. This protects the thermometer from damage, on the one hand, and on the other hand, it is not necessary to replace it.
you need to stop the process.
WIKA 52 - Bimetal thermometer for axial and radial process connection, range up to +500 °C
The bimetallic thermometer of this series was designed specifically for installation in pipes and tanks.
Bimetallic thermometer uses bimetallic plates as a measuring element. Bimetal plates are metals that have different coefficients of linear expansion when measuring temperature. They are twisted into a helical spiral, the other end is fixed to the movable axis. When measuring temperature, the spiral rotates in proportion to the magnitude of the change, the transmission occurs through the axis and further through the tube-sector mechanism to the arrow.
WIKA 70 - Liquid thermometer with capillary, stainless steel case
Due to its versatile design, this type of liquid thermometer has found wide application in mechanical engineering, the refrigeration industry and air conditioning systems. A liquid thermometer can be installed at almost all measuring points. The capillary model is used for measurements at points that are difficult to access or that are at a considerable distance.
The body, capillary and stem are made of stainless steel. For optimal adaptation to the measuring process, various capillary lengths are available, up to a maximum length of 10 mm, and connection forms.
WIKA 32 - Industrial glass V-shaped thermometer
Industrial glass thermometers - Model 32 are mainly used in various industries such as mechanical engineering, energy, refrigeration.
A feature of these thermometers is high accuracy and durability (due to the absence of mechanical wear parts).
WIKA 100.12 - Thermomanometer, pressure and temperature measurement in one device
The thermomanometer with bimetal system is installed directly at the measuring point through the stem. The presence of the valve allows you to unscrew the measuring device without draining the water from the heating system. Thanks to the combination of pressure gauge and bimetal thermometer, the measuring instrument can be used in a wide range of applications.
WIKA IFC - Manometric thermometer with capillary
Capillary thermometer model IFC is a universal manometric thermometer for mechanical engineering, refrigeration and food industries, as well as heating, ventilation and air conditioning systems.
Temperature measurement occurs due to the expansion of the thermometric liquid in the capillary.
This type of capillary thermometer is used to measure temperature in hard-to-reach places, as well as in places that are at a considerable distance.
Thanks to its simple design and plastic housing, the IFC capillary thermometer is an inexpensive and very reliable measuring instrument.
WIKA TF58, TF59 - Manometric thermometer with capillary
Liquid thermometer, models TF 58 and 59, are drum-type measuring instruments.
Different versions have different accuracy, scale range, dimensions, mounting and panel frame design.
WIKA MFT - Thermomanometer with remote line and capillaries, pressure and temperature measurement in one device
The thermomanometer is installed in the panel and allows you to measure pressure and temperature simultaneously. The thermomanometer has a compact design with a front flange and side latches, making it easy to install and integrate into the ergonomics of dashboards. The capillary simplifies the possibility of remote mounting of the indicating part of the device and the measuring point.
The thermomanometer has a Bourdon tube as a sensitive element for measuring pressure. A manometric thermometer filled with liquid is used to measure temperature. A liquid-filled pressure gauge thermometer converts the change in pressure within a closed system of hollow tube and capillary into temperature and transmits this rotation to the pointer.
To measure and constantly monitor the temperature of the working medium (liquid or gas), which are transported through pipelines or located in heating devices, special measuring instruments are used - thermometers. Such devices allow measurements to be made with a high degree of accuracy, are durable and versatile. They are used in various fields, both in industry and in everyday life.
All thermometers are divided into several types:
- liquid;
- mechanical;
- electrical;
- optical.
In everyday life, the most widely used are bimetallic and liquid thermometers, which we offer to buy in Moscow from us.
Liquid thermometers
The operation of such a device is based on the ability of the liquid inside the capillary tube to expand with increasing temperature. For technical purposes, kerosene thermometers are the best option.. The working fluid in such thermometers is colored kerosene, which, unlike mercury thermometers, is considered the safest.
Mercury thermometers are practically not used for technical purposes, since during use there is a high probability of damage to the thermometer, and mercury vapor is very dangerous for human health. In terms of measurement accuracy, kerosene thermometers are in no way inferior to mercury thermometers.
The temperature measurement range of the kerosene thermometers presented on our website varies from 0 to 100 °C. The existing scale allows you to control the temperature with an accuracy of one degree.
The shape of a thermometer with a long stem is most convenient for determining the temperature of hot coolants.
Advantages of kerosene thermometers:
- very easy to operate and maintain;
- all elements of the measuring device are sufficiently reliable and safe;
- compact, it is easy to install it in the required place;
- high measurement accuracy.
Disadvantages of kerosene thermometers:
- low resistance to mechanical damage;
- possible stratification of the liquid in the capillary with a sharp shake.
Bimetal thermometers
This type of thermometer is used not only in industrial enterprises, but also in everyday life, to determine the temperature in rooms, baths, saunas, swimming pools, greenhouses, heating systems, etc.
The device of such thermometers excludes the use of any technical liquids for measurement. Such a thermometer works due to the elastic deformation of two interconnected metal elements in the form of plates that have a different coefficient of thermal expansion. Such a thermometer is an excellent alternative to liquid temperature measuring instruments.
A bimetallic thermometer is used to determine the temperature of any medium - liquid, gaseous or granular. Temperature measurement range — - 70… +600 °С.
You can buy bimetallic thermometers in Moscow in two types:
- Needle- have a special needle-probe for immersion in the working environment.
- Pipe– produce temperature control in heating systems and on the surface of transporting pipes.
Advantages of bimetal thermometers:
- allows you to perform accurate measurements of the environment;
- long service life without routine maintenance. Not afraid of minor mechanical stress;
- convenient design that allows quick reading of temperature indicators;
- easy to install, does not require special conditions;
- All parts are made of corrosion resistant materials.
Disadvantages of bimetallic thermometers:
- high inertia (some delay in temperature change readings);
- Higher cost when compared to liquid thermometers.
Frames for thermometers
Such products are designed to protect glass thermometers from mechanical stress that can lead to damage.
The body of such a frame has a viewing window for monitoring the readings of the thermometer. The frame is fastened to parts and pipelines using screws. To install frames in pipes having different diameters, special bosses are used. To reduce thermal resistance, the gap between the inner wall of the frame and the thermometer bulb is filled with a material with a high thermal conductivity.
You can buy various types of thermometers in Moscow, as well as frames for them, in our online store at affordable prices.
