Classification by function
Calibration of analog pressure gauges
By its purpose pressure gauge for high or low pressure is a general technical, reference or special.
General Technical
Such devices help measure the indicators of maximum and vacuum pressure and are used most often in production, including in the process of technological work. They are suitable for measurements in gaseous media, and they must be non-corrosive for copper alloys at temperatures up to 150 degrees. These devices withstand vibrations from 10 to 55 Hz, the amplitude up to 0.15 mm, their accuracy class varies from 1 to 2.5.
Reference
Devices of this type are designed for testing, adjusting and calibrating other devices to provide the most accurate measurements. Such pressure gauges for measuring gas pressure are divided into three categories, and their list includes control and reference regulators, as well as their analogues designed for ordinary and composite cylinders. Gas gauges of the first type are used most frequently and help control the reliability of these devices in places of installation, their working range varies from 0.06 to 1600 bar.
Special
Special regulators are designed for a specific type of gas and the environment it creates. The bodies of such devices are painted in different colors, taking into account the type of substance for which they are designed. Pressure gauges of this type are made of solid materials that can withstand exposure to gaseous media. They are considered the most common and are characterized by a simple design.
All about electronic pressure gauges
To know all about the electronic pressure gauges now more relevant than ever. Different digital models to measure water and gas pressure in the boiler deserve attention. It is also worth familiarizing with the nuances of the choice of reference hydraulic pressure gauge.
What should be the gas pressure in pipes
Different sections of the pipeline have different pressures. The standards are as follows.
Checking and Adjusting the Outlet Gas Pressure going to the Burner Tubes on a Gas Furnace!
- Line gas. in the pipeline class 1 is maintained from 2.5 to 11.8 MPa, in the pipeline class 2. from 1 to 2.5 MPa.
- Autonomous system. the gas pressure in the gas line of a private home should be in the range of 3 to 6 bar. Manometer is installed on the gas holder and evaluates the level of supply. If the reading drops below 1.5 bar, you must call in a gasoline truck to refuel. Often another analyzer is installed after the pressure regulator. The standard value at this point is 37-39 mbar. Attention should be paid to the constancy of the figure. Manometer on the basement inlet. third control point of the system, must show the same value as the device at the reducer. 37-38 mbar.
- In an apartment and a private home. the standard is the figure in 0.3-0.6 MPa. In recent years, buildings are sometimes supplied with medium pressure networks. from 0,6 to 1,2 MPa. This is due to the widespread installation of gas boilers for heating.
The pressure gauge allows you to monitor the pressure in the house network and take action in time in case of equipment failure or leakage.
Devices to measure the pressure
There is often an acute need for a pressure measurement device for liquids and gases. The operating pressure limits require continuous monitoring in each pipe system or tank and gas pressure gauges or measuring devices are used for this purpose. A good gas pressure meter will guarantee constant operation of the equipment, regardless of the system used, where there is pressure, whether it is a gas pipeline, a heating circuit or a closed circuit.
Factors to consider when choosing a gas measuring device:
Pressure gauges
A pressure gauge is a measuring device or apparatus for measuring differential (e.g., dp05 differential pressure sensor for liquids gases), absolute or gauge pressure. The most common are designed to measure only gauge pressure. “Zero” in such a device is in accordance with the air pressure level. There are pressure gauges that are designed for universal measurement, for example, fd 09. gas pressure gauge.
How is a gas pressure measured?
1 Newton per meter square is equal to 1 Pascal, and 1 atmosphere is equal to 101325 Pascal. A unit such as “bar” is equal to 105 Pa.
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There are the following types of pressure gauges for measuring gas pressure according to their purpose:
What devices to measure gas pressure
At the moment, advanced technology allows the use of different types of devices that show the pressure value in certain intervals:
- Electronic pressure gauges are highly accurate. These devices can operate from 0, up to temperature extremes. One such device is an electronic pressure gauge for measuring gas pressure ht.
- Manovacuum gauges are used for overpressure from. to
- Vacuum gauges (subdivided into tugometers and the less common tugonaporometers) are used for lower atmospheric pressure in the range from.1 to 0.
- Pressure gauges that are designed for extremely low values up to 40 kPa.
Purpose of pressure gauges for measuring low gas pressure KM (KMV)
Pressure gauges KM (KMV) are used to measure pressure of dry, gaseous media, non-aggressive to copper alloys.The principle of operation of low pressure gas pressure gauges KM is based on the dependence of the measured pressure on the deformation of the sensing element, which is used as a diaphragm box. The center of the diaphragm box moves under the influence of the measured pressure and rotates the arrow of the pressure gauge KM (KMV) with a special transmission mechanism.
How to choose a pressure gauge to regulate the gas boiler
When choosing devices, you need to consider: type, measuring range, accuracy class, size, functional load, operating conditions.
Types of devices
According to the structure and principle of operation, there are 5 main types of sensors:
Spring and liquid instruments. the most popular. They are quite accurate and reliable at their low price. These two types are well suited for private homes and small businesses. Spring pressure gauges are used in most boiler rooms.
Gas pressure measuring range
This is the most important parameter when choosing measuring equipment for the boiler.
The main thing is that the working pressure in the boiler pipe falls within the range of 1/3-2/3 of the measuring scale of the device. If the pressure is less, the measurement inaccuracy is too high, and if it is more. the device will be overloaded and will fail before the warranty period.
Accuracy class
The smaller the reading, the more accurate the instrument. Accuracy class is the percentage of measurement error from the measurement scale.
The uncertainty is easy to calculate, e.g. if the device is for 10 atm. has an accuracy class of 1.5., then its permissible error is 1.5%. If the device index is higher, it must be replaced.
It is possible to determine the fault only with the help of a reference pressure gauge, this is done by a special organization that performs verification of equipment. A precision instrument is connected to the system and then the readings are compared.
Size
The diameter of the device is chosen according to the application.
- 50, 63 mm. for installation on portable equipment or for pressure control of oxygen cylinders, welding machines.
- 100 mm is the most common size and the most convenient in most cases.
- 160 mm, 250 mm. to control appliances that are visually far away, for example, under the ceiling of a boiler room.
Functional load
According to the type of functional load devices are:
- Indicating. are devices of technical direction. Measuring pressure.
- Alarms. control an external circuit.
- For precise measurements have an accuracy grade of 0.6-1.0.
- Reference are used to check the accuracy of other instruments.
- Self-recording ones record the pressure in the form of a diagram on paper.
Sample pressure gauge for the gas boiler. The device has a high accuracy, it is used to calibrate other devices.
Operating conditions
A gauge needs to be chosen specifically for the environment in which it will be used. The medium can be different, including aggressive. There are instruments with different housings, it is important to consider whether it will operate in conditions of humidity, dust, vibration, to prevent the development of corrosion or damage to the housing.
Measuring gas pressure
The main indicator that characterizes the gas consumption network is the gas pressure in the pipeline. Providing of the normative gas pressure before the gas using equipment allows to provide qualitative fuel combustion and stable operation of burners.
Pressure is the ratio of the force to the area on which it acts, and for a gas, the force with which it acts on a unit of the surface area of a vessel. Pressure counted from absolute zero is called absolute, the pressure exerted by the atmosphere is called atmospheric. Excess pressure is greater than atmospheric pressure; it is counted from the atmospheric pressure already present:
where P in. excess pressure; P ABS. absolute pressure; P atm. atmospheric pressure.
When measuring rarefaction they define how much the pressure in a limited volume is less than the atmospheric pressure. This pressure is called vacuum-metric pressure:
During maintenance and repair of in-house gas equipment, the overpressure of gas or water is monitored, as well as the vacuum pressure when measuring the vacuum in smoke removal systems.
In the SI system, the basic unit for measuring pressure is the Pascal (Pa). One pascal is the pressure exerted by a force of one newton (N) on an area of one square meter (m²).
Millimeters of water column (mm.water. millimeter of water column (mm.s.c.).). This unit is readily apparent and comprehensible, particularly with a liquid pressure gauge.
In Western Europe bar (bar) is used to measure pressure. One bar is equal to 100.000 Pa, which is approximately equal to 1 kgf/cm². One millibar (mbar) is 100 Pa, it is approximately 10 mm.в.st (1 mbar is 10 mm.в.st.). The primary unit used in this book in describing gas fuel equipment is bar. The unit of measure used to characterize the state of a gas fuel is the Pascal (daPa).
The Pascal is very small, and in practice multiples of it are used:
1 decapascal (1 daPa) = 10 Pa. 1 mm.в.st; 1 hectopascal (1 hPa) = 100 Pa.1 mbar; 1 kilopascal (1 kPa) = 1000 Pa.100 mm.в.st.1 Megapascal (1 MPa) = 1000000 Pa. 10 kgf/cm² or 1 kgf/cm². 0.1 MPa.
It should be noted that the exact value of 1 mm.в.st = 9.81 Pa, and 1 kgf/cm² = 9.81 x 104 Pa, but for practical purposes it is sufficient to remember that 1 mm.в.st.10 Pa (1 daPa) and 1 kgf/cm² is 0.1 MPa.
When measuring overpressure or vacuum, its value is determined by means of special pressure gauges, pressure gauges, and vacuum gauges. Accuracy of measurement is characterized by error. deviation of measurement result from the true value of the measurand. The accuracy class of an instrument is characterized by the maximum permissible error, the maximum error at which the instrument is valid and approved for use. The indicating spring pressure gauges are available in the following accuracy classes: 0.4; 0.6; 1; 1.5; 2.5; 4. Pressure gauge with accuracy class 1.5 Measurement results may differ from the true value by as much as 1.5%.
Liquid U pressure gauges are used to measure small pressure values, most often low (up to 500 daPa). They are used to measure gas pressure as well as air pressure for combustion in forced-air burners. A liquid pressure gauge is a glass or transparent plastic U-shaped tube that is attached to a wooden or plastic panel. It is marked in millimeters, from zero upwards and from zero downwards. In modern pressure gauges the scale may have divisions in pascals (Pa).
Gas Pressure Measurement
The main feature of gas consumption networks is the gas pressure in the pipeline. Provision of standard pressure of gas in front of gas consuming equipment allows to provide quality fuel combustion and stable operation of burners.
Pressure is the ratio of the force to the area on which it acts, and for gas, the force with which it acts on the unit surface area of the vessel. Pressure counted from absolute zero is called absolute pressure, the pressure exerted by the atmosphere is called atmospheric pressure. Excess pressure greater than atmospheric pressure, it is counted from the atmospheric pressure already present:
where P rbs. excess pressure; P ABS. absolute pressure; P atm. atmospheric pressure.
When measuring vacuum, the pressure in any limited volume is less than the atmospheric pressure. This pressure is called vacuum-metric pressure:
During maintenance and repair of in-house gas equipment, the excess pressure of gas or water is monitored, and vacuum pressure when measuring vacuum in smoke removal systems.
In the SI system, the basic unit of pressure is the Pascal (Pa). One pascal is the pressure exerted by a force of 1 newton (N) on an area of 1 square meter (m²).
The unit of measure for gas pressure in domestic gas pipes is often in the millimetre of water column (mm.water. st.). This unit is easy to read and understand, especially when using a liquid pressure gauge.
In Western Europe, bar (bar) is used to measure pressure. One bar equals 100.000 Pa, which is approximately equal to 1 kgf/cm². One millibar (mbar) is 100 Pa, this equals approximately 10 mm.в.St (1 mbar = 10 mm.в.st.). The basic unit used in this book in describing gas equipment is bar. The unit of measure used to characterize the state of a gas fuel is the Pascal (daPa).
The pascal is very small, in practice multiple units are used:
1 decapascal (1 daPa) = 10 Pa. 1 mm.в.st; 1 hectopascal (1 hPa) = 100 Pa.1 mbar; 1 kilopascal (1 kPa) = 1000 Pa.100 mm.в.st.1 Megapascal (1 MPa) = 1000000 Pa. 10 kgf/cm² or 1 kgf/cm². 0,1 MPa.
It should be noted that the exact value of 1 mm.в.St = 9.81 Pa, and 1 kgf/cm² = 9.81 x 104 Pa, but for practical purposes it is sufficient to remember that 1 mm.в.st.10 Pa (1 daPa), and 1 kgf/cm² is 0.1 MPa.
When measuring overpressure or vacuum, its value is determined by means of special instruments manometers, pressure gauges, draught gauges. Accuracy of measurement is characterized by error. deviation of measurement result from true value of measured quantity. accuracy class of the device is characterized by the maximum permissible error limit. the maximum error of the device, at which it can be recognized suitable and approved for use. Indicating spring pressure gauges come in the following accuracy classes: 0.4; 0.6; 1; 1.5; 2.5; 4. In a pressure gauge with accuracy class 1.accuracy class 5 the measurement result may differ from the true value by not more than 1.5.
Liquid U pressure gauges are used to measure small pressure values, most often low (up to 500 daPa). They are used to measure the gas pressure as well as the combustion air pressure in forced-air burners. Liquid pressure gauge is a glass or transparent plastic U-shaped tube, which is attached to a wooden or plastic panel. The panel has a scale with divisions in millimeters, from zero upwards and from zero downwards. Modern manometers have a scale in pascals (Pa).
Pressure gauges for boilers
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Pressure gauge is a measuring instrument, which is necessary for measurement of pressure of liquids, steam and gas, which are not aggressive to copper alloys. Scale of pressure gauge measurements from 0,06 to 1000 MPa (pressure is measured in excess).
Pressure gauges are widely used at enterprises of various industries (petrochemical, chemical, mining and metallurgical, etc) and in other industries.д.), in medicine, agriculture, engineering, transport, housing and communal services, construction and almost all areas of life.
There are also accuracy classes of pressure gauges: 0,15; 0,25; 0,4 etc.д. As the number increases, the accuracy of the device decreases accordingly.
The body of technical manometer in a traditional factory version is made of steel, the socket is made of brass. Such pressure gauges are mainly used in the housing and utilities sector and machine building. Boiler pressure gauges have a dial with a larger diameter. This is a prerequisite for visual pressure control of boiler units.
