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About Gas Meters
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What was a gas meter?
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Measuring instruments for natural gas, liquid gases (propane, butane) and refrigerants
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Measuring instruments for the determination of the oxygen content
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Measuring devices for carbon monoxide (CO) and exhaust gas measuring devices
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Measuring devices for carbon dioxide (CO2) (air quality measuring devices)
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Measuring instruments for determining the flow velocity of air: Anemometers
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Our practical tip: Protect measuring range from drafts
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FAQ – frequently asked questions about gas meters
What was a gas meter?
Mobile gas meters are battery-operated, handy and compact gas detectors for the interior. They check the ambient air for increased levels of different gases and display measured values. If the gas concentration rises above the specific limit values for the respective gases, an optical signal is displayed or an acoustic alarm sounds. Different types of gas detectors exist for the detection of the presence of different gases. In addition, multi-gas warning devices are available that react as combination devices to different types of gas.
Gas meters function differently depending on the type of gas to be detected. While gas measurement technology in natural gas/liquid gas detectors, oxygen detectors and CO detectors is based on electrochemical sensors that evaluate electrochemical processes specific to the type of gas in question, a CO2 measuring device with an IR measuring cell works.
Measuring instruments for natural gas, liquid gases (propane, butane) and refrigerants
Natural gas is a combustible gas mixture whose main content is methane. It is mainly used for heating residential and commercial premises, as heating agent for industrial thermal processes or as fuel or fuel for motor vehicles or ships.
Liquefied gases are, in the narrower sense, gases that remain liquid at room temperature under relatively low pressure, they are mainly propane and butane and their derivatives. Liquid gas is used as a refrigerant in air conditioning systems, as a fuel for heating purposes, as a car gas, for soft soldering and in small quantities for cooking in the camping area or for the gas grille.
Escaping natural gas or liquid gas from defective supply lines, thermal baths, heaters, gas cookers, air conditioning systems or gas cylinders can become a hazard because it forms a highly explosive gas mixture in a specific mixture with oxygen , to which ignition a spark or an electrical impulse suffices.
Sensors inside the measuring device for natural gas and liquid gas measurement already detect small quantities of gases . The devices warn by an acoustic, many devices additionally by an optical alarm. This is already the case when the gases are enriched below the lower explosive limit, i.e. at the mixing ratio with the lowest proportion of natural/liquid gas from which the mixture is classified as explosive.
While natural gas has a lower density than air and rises in space, liquefied gases with a higher density than air in space are decreasing . This must be taken into account when carrying out the measurement. This means that the measuring instrument is held at the possible exit point or at ceiling level when measuring the natural gas concentration, while the measuring of liquid gases is carried out at the possible exit point or at the floor level.
Special measuring devices for detecting escaping refrigerant (liquid gases) have a flexible gooseneck, which enables measurement in places that are difficult to access.
Measuring instruments for the determination of the oxygen content
Oxygen is used in industrial applications, especially when welding and soldering as an admixture to the fuel gas. In food technology, it is used as a food additive E 948 as a fuel or packing gas, and is also part of a gas mixture in the diving sector (Nitrox, Trimix, or similar gas mixtures).
Although direct effects on health only occur after prolonged exposure to pure oxygen or air with increased oxygen content, the release of oxygen due to its oxidizing effect can become dangerous, especially if oxygen mixes uncontrolled with other gases. These gas mixtures are highly explosive in their respective characteristic mixing ratios, electrical impulses are already sufficient for ignition , for example by activating a light switch.
In the diving area, it is essential to check the oxygen content of the immersion gas mixtures before each dive.
Oxygen meters are equipped with a sensor for electrochemical determination of the oxygen content. Measuring devices for the diving range also show the maximum possible diving depth for the respective measured value.
Measuring devices for carbon monoxide (CO) and exhaust gas measuring devices
Carbon monoxide is a gas which cannot be detected by human senses and can be produced at insufficiently ventilated combustion sites and as a component of exhaust gases and can be harmful even at low concentrations.
In most households and businesses, there are various potential sources of carbon monoxide , which generally include all fireplaces and combustion facilities. These include gas, wood, oil and pellet stoves, heating and decorative fireplaces, but also gas heaters and boilers, water heaters, gas-operated heaters, motors and all appliances in which fuels such as coal, oil, gas or wood are burned under insufficient oxygen supply.
Carbon monoxide measurement devices detect the concentration of carbon monoxide in closed rooms via a highly sensitive electrochemical sensor and display the measured values on a display, as well as increased measured values by an alarm signal.
Measuring devices for carbon dioxide (CO2) (air quality measuring devices)
Air quality meters monitor the ambient air and display measurement data such as temperature, relative humidity, air pressure and carbon dioxide content (CO2 content) of the air.
The harmful effect of carbon dioxide is due to the displacement of the oxygen in the air. Increasing carbon dioxide concentrations are reflected by fatigue, lack of concentration, headache and dizziness, and as CO2 levels continue to rise, the respiration rate and blood pressure increase.
In rooms where fermentation processes are taking place, for example in wine cellars and fodder silos, considerable amounts of carbon dioxide are often found in the air.
The concentration of carbon dioxide is considered to be the most important indicator of indoor air quality. The room air is divided into four quality levels depending on the concentration of carbon dioxide by DIN EN 13779:
Below 800 ppm, the air quality is considered good, between 800 and 1000 ppm are considered average, between 1000 and 1400 ppm only moderate quality. If the carbon dioxide part exceeds 1400 ppm, air quality should be considered low.
The MAK (maximum workplace concentration) is 5000 ppm per working day (8 hours).
Air quality measuring devices determine the CO2 concentration via an IR measuring cell, which enables the acquisition of precise measured values with measuring and reference wavelength.
Measuring instruments for determining the flow velocity of air: Anemometers
Comfort measurements at the workplace, air flow measurements on air conditioning systems, exhaust systems, fans, and meteorological studies are carried out using an anemometer.
Different measuring methods are used in different devices of this type:
- The impeller anemometer determines the wind speed of the air flow by turning a impeller installed in the wind gauge.
- The heat-wire anemometer measures the cooling speed of a wire heated to a certain temperature. The speed of the air flow can be reliably calculated from the duration of the cooling, the temperature of the wire and the outdoor temperature.
- The tailpipe anemometer has a slim tube with a sensor to measure the pressure generated by the incoming air. The air speed is calculated from these measurement data.
Our practical tip: Protect measuring range from drafts
When using gas measuring devices, make sure not to measure in the immediate vicinity of windows, balcony doors and fans (this does not apply to anemometers), as the higher air circulation in these places would cause the measured values to be falsified!
FAQ – frequently asked questions about gas meters
Why do gas meters need to be calibrated?
The measuring accuracy suffers from prolonged storage of the device, air humidity effects, heat or other external influences, therefore regular calibrations are necessary.
Gas meters that are not subject to calibration must be calibrated regularly. Calibration is used for quality assurance of the measurement results. For this purpose, measurements are carried out on a known standard and deviations are logged. This means that the respective measuring device is reset to an output value during calibration.
What are the differences between gas meters?
Different gas meters of the same type differ in the scope of their additional functions. Models with displays can display measured values, there are differences in the size of the measured value memory and in the width of the measuring range. Some devices have adjustable alarms. CO2 meters are available for wall mounting and portable versions.