Radial connection. Thermomanometers type TMTB (radial connection)

The radial bimetallic thermometer is 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 deformation sensitive 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, having 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.

The thermometer body is made of corrosion-resistant steel, the stem is made of 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.

Case diameter

Accuracy class

Temperature ranges

−30…+70 °С* −40…+60 °С**

0…+60 °С 0…+100 °С

0…+120 °С 0…+160 °С

0…+200 °С 0…+250 °С

0…+350 °С 0…+450 °С * - only for Ø100

** - only for Ø63

Working temperature

Environment: −10…+60 °C

Degree of protection

Immersion length, mm

46; 64 (except t°=0…+60 °C);

150 (for Ø63 only up to 250 °C);

200, 250 and 300 (only for Ø100)

Frame

Corrosion resistant steel

Ring

Corrosion-resistant steel, bayonet

Stock

Stainless steel

Sensing element

Bimetallic spiral

Clock face

Aluminium, black scale on white background

Glass

Mineral

Accession

Radial

Connection thread

on the sleeve - G½ or M20×1.5

Operating pressure

on the sleeve - 10 MPa (100 kgf/cm²)

Adjustment

Calibration interval

3 years - with measurement range +20...+100 °C, +20...+140 °C

2 years - for all other ranges

The term “pressure gauge” used in the text is general and, in addition to pressure gauges itself, also implies vacuum gauges and pressure-vacuum gauges. IN this material Digital devices are not considered.

Pressure gauges are one of the most common devices in industry and housing and communal services. For more than a hundred years they have been reliably serving people. The needs of production initiated the development of pressure gauges for various purposes, differing in size, design, connecting thread, ranges and units of measurement, accuracy class. Incorrect choice devices leads to their premature failure, insufficient measurement accuracy or overpayment for unnecessary functionality.

Pressure gauges can be classified according to the following criteria.

1. By area of ​​application.

1.1. Standard technical pressure gauges are designed for measuring excess and vacuum pressure of non-aggressive, non-crystallizing liquids, steam and gas.

1.2. Technical special - pressure gauges for working with specific media or under specific conditions. The following pressure gauges are special:

Oxygen;

Acetylene;

Ammonia;

Corrosion resistant;

Vibration-resistant;

Ship;

Railway;

Pressure gauges for the food industry.

Oxygen pressure gauges are structurally no different from technical pressure gauges, but during the production process they undergo additional cleaning from oils, since when oxygen comes into contact with oils, ignition or an explosion can occur. The designation O 2 is applied to the scale.

Acetylene pressure gauges are manufactured without the use of copper and its alloys. This is due to the fact that the interaction of copper and acetylene produces explosive copper acetylene. Acetylene pressure gauges are marked with the symbols C 2 H 2.

Ammonia and corrosion-resistant pressure gauges have mechanisms made of stainless steel and alloys that are not subject to corrosion when interacting with aggressive environments.

The design of vibration-resistant pressure gauges ensures operability when exposed to vibration in a frequency range approximately 4-5 times higher than the permissible vibration frequency of standard technical pressure gauges.

Some types of vibration-resistant pressure gauges can be filled with damping fluid. Glycerin (operating temperature range from -20 to +60 o C) or PMS-300 liquid (operating temperature range from -40 to +60 o C) is used as a damping liquid.

Pressure gauges for the food industry do not have direct contact with the medium being measured and are separated from it by a membrane separating device. The space above the membrane is filled with a special liquid, which transmits force to the pressure gauge mechanism.

Pressure gauge housings are usually painted in a color corresponding to the application: ammonia - yellow, acetylene - white, for hydrogen - dark green, for flammable gases, for example, propane - red, for oxygen - blue, for non-flammable gases - in black.

2. Electric contact (signaling) pressure gauges.

Electric contact (signaling) pressure gauges include contact groups for connecting external electrical circuits. Used to maintain pressure in technological installations within a given range.

Contact groups of electrical contact (signaling) pressure gauges in accordance with GOST 2405-88 can have one of four designs:

III - two break contacts: left indicator (min) - blue, right (max) - red;

IV - two closing contacts: left indicator (min) - red, right (max) - blue;

V - left normally open contact (min); right closing contact (max) - both indicators are blue;

VI - left normally open contact (min); right contact is normally closed (max) - both indicators are red.

Most Russian factories accept version V as standard. That is, if the application does not indicate the design of the electrical contact pressure gauge, then the customer is almost guaranteed to receive a device with contact groups of this design. In the absence of a passport, you can determine the design of the contact groups by the color of the indicators.

Electroconical (signaling) pressure gauges are divided into general industrial and explosion-proof. The ordering of explosion-proof pressure gauges must be approached very carefully so that the type of explosion protection of the device corresponds to the high-risk facility.

3. Pressure units.

Pressure gauge scales are calibrated in one of the following units: kgf/cm2, bar, kPa, MPa. However, you can often find pressure gauges with a double scale. The first scale is graduated in one of the units listed above, the second in psi - pound-force per square inch. This unit is non-systemic and is used mainly in the USA. In table 1 shows the relationship between these units.

Table 1. Ratio of pressure units

Instruments calibrated in kPa are called pressure gauges for measuring low pressures gases A membrane box is used as a sensing element, while in pressure gauges for high pressures a curved or spiral tube is used.

4. Range of measured pressures.

In physics, there are several types of pressure: absolute, barometric, excess, vacuum. Absolute pressure is pressure measured relative to absolute vacuum. Absolute pressure cannot be negative.

Barometric is Atmosphere pressure, which depends on altitude above sea level, temperature and humidity. At zero meters above sea level it is taken to be 760 mm mercury. In technical pressure gauges, this value is taken as zero, that is, the value of barometric pressure does not affect the measurement results.

Gauge pressure is the difference between absolute pressure and barometric pressure, provided that the absolute pressure exceeds the barometric pressure.

Vacuum is the difference between absolute pressure and barometric pressure, when absolute pressure is less than barometric pressure. Therefore, vacuum pressure cannot be greater than barometric pressure.

Based on this, it becomes clear that vacuum gauges measure vacuum. Pressure and vacuum gauges cover the vacuum region and overpressure. Pressure gauges measure excess pressure. There is another class of instruments called differential pressure gauges. Differential pressure gauges are connected to two points of one system and show the pressure difference of gaseous or liquid substances.

The ranges of measured pressures are standardized and assumed to be equal to a certain range of values, which are given in table. 2.

Table 2. Standard range of values ​​for calibration of scales.

5. Accuracy class of pressure gauges

Accuracy class is the permissible error of a device, expressed as a percentage of the maximum scale value of a given device. The accuracy class is applied by manufacturers to the scale. The lower this value, the more accurate the device. The same type of pressure gauge may have different class accuracy. For example, the Manotom plant produces devices with an accuracy class of 1.5 as standard, and can produce similar devices with an accuracy class of 1.0 upon request. In table 3 shows data on accuracy classes in relation to various types pressure gauges.

Table 3. Accuracy class of pressure gauges from Russian manufacturers.

For imported devices, the accuracy class value may differ slightly from Russian analogues. For example, European technical pressure gauges may have an accuracy class of 1.6.

The smaller the diameter of the device body, the lower its accuracy class.

6. Case diameter

Most often, pressure gauges are manufactured in cases with the following diameters: 40, 50, 60, 63, 100, 150, 160, 250 mm. But you can find devices with other body sizes. For example, vibration-resistant pressure gauges produced by Fiztekh, type DM8008-Vuf (DA8008-Vuf, DV8008-Vuf) are manufactured in cases with a diameter of 110 mm, and a smaller version of this device, DM8008-Vuf (DA8008-Vuf, DV8008-Vuf) Version 1, has diameter 70 mm.

Pressure gauges with a body of 250 mm are often called boiler gauges. They do not have special designs and are used at thermal power facilities and allow the operator to control pressure at several nearby installations from the operator’s workplace.

7. Design of pressure gauges

A fitting is used to connect the pressure gauge to the system. There are radial (bottom) location of the fitting and axial (rear) location. The axial fitting can be centrally located or offset relative to the center. Many types of pressure gauges available design features They are not available with an axial fitting. For example, signaling (electric contact) pressure gauges are made only with radial fitting, since the electrical connector is located on the back side.

The size of the thread on the fitting depends on the diameter of the body. Pressure gauges with diameters of 40, 50, 60, 63 mm are manufactured with threads M10x1.0-6g, M12x1.5-8g, G1/8-B, R1/8, G1/4-B, R1/4. On pressure gauges bigger size M20x1.5-8g or G1/2-B is used. European standards provide for the use of not only the above types of threads, but also conical ones - 1/8 NPT, 1/4 NPT, 1/2 NPT. In addition, industry uses specific connections. Pressure gauges measuring high and ultra-high pressures can have internal conical or cylindrical threads.

The design of the pressure gauge body depends on the installation method and location. Devices installed openly on highways, as a rule, do not have additional fastenings. When installed in cabinets, control panels, pressure gauges with a front or rear flange are used. The following versions of pressure gauges can be distinguished:

With radial fitting without flange;

With radial fitting with rear flange;

With axial fitting with front flange;

With axial fitting without flange.

Standard pressure gauges usually have a degree of protection IP40. Special pressure gauges, depending on the application, can be manufactured with degrees of protection IP50, IP53, IP54 and IP65.

In some cases, pressure gauges must be sealed in order to prevent the possibility of unauthorized opening of the devices. For this purpose, some manufacturers make an eye on the body and complete it with a screw with a hole in the head, allowing the seal to be installed.

8. Protection against high temperatures and pressure changes

Temperature has a serious influence on the measurement error and service life of pressure gauges. This factor affects the internal elements of the structure upon contact with the measured medium, and externally through the ambient temperature.

Most pressure gauges should be operated at an ambient and measured medium temperature of no more than +60 o C, maximum +80 o C. Some manufacturers manufacture instruments designed for temperatures of the measured medium up to +150 o C and even +300 o C. However, measurements at high temperatures can be produced using standard pressure gauges. To do this, the pressure gauge must be connected to the system via a siphon outlet (cooler). A siphon tap is a tube special form. At the ends of the outlet there is a thread for connecting to the main line and attaching a pressure gauge. The siphon outlet forms a branch in which there is no circulation of the measured medium. As a result, at the point where the pressure gauge is connected, the temperature may differ significantly from the temperature in the main line.

Another factor affecting the longevity of pressure gauges is sharp changes pressure or water hammer. To reduce the influence of these factors, dampers are used. The damper can be made as a separate device installed in front of the pressure gauge or mounted in the internal channel of the device holder.

There is another way to protect the pressure gauge. In cases where there is no need to constantly monitor the pressure in the system, a pressure gauge can be installed through a push-button valve. Thus, the device will be connected to the controlled line only for the time during which the tap button is pressed.

Pressure gauges are a broad group of mechanical devices designed to measure the pressure of various media. The importance of these devices cannot be overestimated because pressure control is an important procedure for many industrial sectors.

Image	Name	Price per piece VAT included
	ACR axial pressure gauge, 0-6 bar	RUB 300.00
	ACR radial pressure gauge, 0-6 bar	RUB 300.00
	Pressure gauge WATTS F+R100 (MAL), G1/4, 0-6 bar, axial	6,5 €
	6,5 €
	6,5 €
	Pressure gauge WATTS F+R200 (MRP), 0-10 bar, radial	6,5 €

Characteristics:

Pressure gauges differ in technical characteristics, accuracy class and scope of application. Each device is necessarily certified by the manufacturer. Pressure gauges are manufactured in the following accuracy classes: 0.2; 0.6; 1.0; 1.5; 2.5; 4.0 (the higher, the higher the accuracy of the device).

According to technical characteristics, pressure gauges are of the following types:

1. Technical. Pressure gauges of this type make it possible to measure both excess and vacuum pressure of neutral liquids and gases that are not subject to crystallization;
2. Electric contact. The pressure of neutral and non-crystallizing media and oxygen is measured. Pressure gauges of this type can be used not only as control device, but also as an actuator capable of blocking the process (pressure switch);
3. Self-recording. Vacuum and excess pressure are measured. Purely a control device. It records on a special medium not only pressure indicators, but also the mode and schedule of its work.
4. Reference. Designed for checking pressure gauges;
5. Water pressure gauge. Used to measure water pressure in heating and water supply systems. There are two types of water pressure gauges - radial and rear (axial).

According to the principle of operation, pressure gauges are divided into three types:

1. Liquid - pressure gauges in which the pressure of the medium is compensated by a column of liquid;
2. Piston - act as a compensator by acting on a freely moving piston;
3. Deformation - the degree of deformation of the control element (bellows, membrane, spring) is measured.

There are two types of pressure gauges based on the connection method:

• Axial (axial) RA, threaded connection is located on the rear panel of the device;
• Radial RV, the thread is located at the bottom of the body.

Pressure gauges for measuring water pressure (axial and radial) are installed in water supply and heating systems using threaded connections. External thread ¼”

You can buy a water pressure gauge from us on favorable terms.

When choosing a pressure gauge for water, you should pay attention to the following parameters

1. Accuracy class;
2. Scope of application;
3. Maximum pressure;
4. Connection method (type and size of thread);
5. Case diameter

The same device can be used in different environments. If its design includes elements that are unstable to certain environments, then the scale of the device will contain symbols that inform about the features of using this device. More detailed information on recommended areas of application is contained in its technical data sheet.

• Manufacturer: Rosma
• Price: from 1,030 rub.
• Scope of application: heating systems, water supply, boilers, steam boilers

Radial thermomanometer is designed for simultaneous measurement of temperature and excess pressure of non-aggressive copper alloys avg.

Thermomanometer is a combined device for measuring pressure and temperature. For visual monitoring of the main parameters of the coolant (pressure and temperature), a pressure gauge and thermometer are usually used. An attempt to combine these two devices led to the creation of a combined device called a thermomanometer.

Structurally, the TMTB thermomanometer combines a deformation pressure gauge and a bimetallic thermometer. Temomanometers have a dial with two scales and two indicating hands. One scale is used to read pressure, the other - temperature. The ROSMA company produces thermomanometers in two sizes: case diameter 80 and 100 mm. Depending on the location of the fitting, thermomanometers can be axial or radial. The length of the immersion part can also vary according to the customer's order. All thermomanometers are equipped with a safety valve.

Prices for thermomanometers type TMTB (radial connection) with VAT, per piece.

• Case diameter: 80, 100 mm
• Accuracy class: 2.5
• Temperature reading ranges: 0…120/150 °C
• Pressure reading range: 0…0.25 / 0.4 / 0.6 / 1 / 1.6 / 2.5 MPa
• Working temperature
  • Environment: −60…+60 °C
  • Measured medium: up to +150 °C
• Housing: IP40, black steel
• Ring: chrome steel
• Measuring element, pointer mechanism, fitting: copper alloy
• Dial: aluminum, black scale on a white background, with color division of temperature and pressure measurement sectors
• Pointer: black aluminum
• Glass: instrument glass
• Connection thread: G½ (on valve)

Standard version Ø80, 100 mm ( radial connection)

Standard version Ø80, 100 mm (valve)

Attention!
The thermomanometer is installed directly on the pipeline (reservoir), without the use of a three-way valve or bellows tube, so that Bottom part the valve was located in the middle part of the pipe. Other installation of TMTB must be agreed with the manufacturer.

Overall dimensions, mm)

* − with an immersion length of 100 mm, devices are manufactured to order