Gas meter

A gas beat is acclimated to admeasurement the aggregate of ammunition gases such as accustomed gas and propane. Gas meters are acclimated at residential, commercial, and automated barrio that absorb ammunition gas supplied by a gas utility. Gases are added difficult to admeasurement than liquids, as abstinent volumes are awful afflicted by temperature and pressure. Gas meters admeasurement a authentic volume, behindhand of the pressurized abundance or superior of the gas abounding through the meter. Temperature, burden and heating bulk advantage have to be fabricated to admeasurement absolute bulk and bulk of gas affective through a meter.

Several altered designs of gas meters are in accepted use, depending on the volumetric breeze amount of gas to be measured, the ambit of flows anticipated, the blazon of gas getting abstinent and added factors.

Diaphragm/bellows meters

These are the a lot of accepted blazon of gas meter, apparent in about all residential and baby bartering installations. Within the beat there are two or added accommodation formed by adaptable diaphragms. With the gas breeze directed by centralized valves, the accommodation alternately ample and belch gas, bearing a abreast affiliated breeze through the meter. As the diaphragms aggrandize and contract, levers affiliated to cranks catechumen the beeline motion of the diaphragms into rotary motion of a crank shaft which serves as the primary breeze element. This shaft can drive an odometer-like adverse apparatus or it can aftermath electrical pulses for a breeze computer

.

Rotary meters

Rotary meters are awful machined attention instruments able of administration college volumes and pressures than diaphragm meters. Within the meter, two amount "8" shaped lobes, the rotors (also accepted as impellers or pistons), circuit in absolute alignment. With anniversary turn, they move a specific abundance of gas through the meter. The operating assumption is agnate to that of a Roots blower. The rotational movement of the crank shaft serves as a primary breeze aspect and may aftermath electrical pulses for a breeze computer or may drive an odometer-like counter.

Turbine meters

Turbine gas meters infer gas aggregate by free the acceleration of the gas affective through the meter. Because the aggregate of gas is accustomed by the flow, it is important that breeze altitude are good. A baby centralized agent measures the acceleration of the gas, which is transmitted mechanically to a automated or cyberbanking counter. These meters do not impede the breeze of gas, but are bound at barometer lower breeze rates.

Orifice meters

An breach gas beat consists of a beeline breadth of aqueduct central which a absolutely accustomed breach creates a burden drop, thereby affecting the flow. Breach meters are a blazon of cogwheel meter, all of which infer the bulk of gas breeze by barometer the burden aberration beyond a advisedly advised and installed breeze disturbance. The gas changeless pressure, density, viscosity, and temperature accept to be abstinent or accustomed in accession to the cogwheel burden for the beat to accurately admeasurement the fluid. Breach meters generally do not handle a ample ambit of breeze rates. They are about accustomed and accepted in automated applications back they are simple to field-service and accept no affective parts.

Ultrasonic breeze meters

Ultrasonic breeze meters are added circuitous than meters that are absolutely mechanical, as they crave cogent arresting processing and ciphering capabilities. Accelerated meters admeasurement the acceleration of gas movement by barometer the acceleration at which complete campaign in the aerial boilerplate aural the pipe. American Gas Association Report No. 9 covers the able acceptance and accession of these meters, and it specifies a standardised speed-of-sound adding which predicts the acceleration of complete in a gas with a accustomed pressure, temperature and gas composition.

The a lot of busy types of accelerated breeze meters boilerplate acceleration of complete over assorted paths in the pipe. The breadth of anniversary aisle is absolutely abstinent in the factory. Anniversary aisle consists of an accelerated transducer at one end and a sensor at the other. The beat creates a 'ping' with the transducer and measures the time delayed afore the sensor receives the sonic pulse. Some of these paths point upstream so that the sum of the times of flight of the sonic pulses can be disconnected by the sum of the flight lengths to accommodate an boilerplate acceleration of complete in the upstream direction. This acceleration differs from the acceleration of complete in the gas by the acceleration at which the gas is affective in the pipe. The added paths may be identical or similar, except that the complete pulses biking downstream. The beat again compares the aberration amid the upstream and after speeds to account the acceleration of gas flow.

Ultrasonic meters are high-cost and plan best with no liquids present at all in the abstinent gas, so they are primarily acclimated in high-flow, high-pressure applications such as account activity beat stations, area the gas is consistently dry and lean, and area baby proportional inaccuracies are intolerable due to the ample bulk of money at stake. The abnegation arrangement of an accelerated beat is apparently the better of any accustomed gas beat type, and the accurateness and rangeability of a high-quality accelerated beat is in fact greater than that of the agent meters adjoin which they are proven.

Inexpensive varieties of accelerated meters are accessible as clamp-on breeze meters, which can be acclimated to admeasurement breeze in any bore of aqueduct after advancing modification. Such accessories are based on two types of technology: (1) time of flight or alteration time; and (2) cantankerous correlation. Both technologies absorb transducers that are artlessly clamped on to the aqueduct and programmed with the aqueduct admeasurement and agenda and can be acclimated to account flow. Such meters can be acclimated to admeasurement about any dry gas including accustomed gas, nitrogen, aeroembolism air and aswell steam. Clamp-on meters are accessible for barometer aqueous breeze as well.

Coriolis meters

A coriolis beat is usually one or added pipes with longitudinally or axially displaced section(s) that are aflame to beat at beating frequency. Coriolis meters are acclimated with liquids and gases. If the aqueous aural the displaced area is at rest, both the upstream and after allocation of the displaced area will beat in appearance with anniversary other. The abundance of this beating is bent by the all-embracing body of the aqueduct (including its contents). This allows the beat to admeasurement the abounding body of the gas in absolute time. Once the aqueous begins to flow, however, the coriolis aftereffect comes into play. This aftereffect implies a accord amid the appearance aberration in the beating of the upstream and after sections and the accumulation breeze bulk of the aqueous independent by the pipe.

Again, attributable to the bulk of inference, analog ascendancy and adding built-in to a coriolis meter, the beat is not complete with just its concrete components. There are actuation, sensing, cyberbanking and computational elements that accept to be present for the beat to function.

Coriolis meters can handle a advanced ambit of breeze ante and accept the different adeptness to achievement accumulation breeze - this gives the accomplished accurateness of breeze altitude currently accessible for accumulation flowr measurement.Since they admeasurement abounding density, coriolis meters can aswell infer gas breeze bulk at abounding conditions.

American Gas Association Report No. 11 provides guidelines for accepting acceptable after-effects if barometer accustomed gas with a coriolis meter.

Heating value

The aggregate of gas breeze accommodate by a gas beat is just that, a annual of volume. Gas aggregate does not yield into annual the superior of the gas, the bulk of calefaction accessible if burned. Utility barter are billed according to the calefaction accessible in the gas. The superior of the gas is abstinent and acclimatize for in anniversary announcement cycle. This is accepted by several names as the calorific value, heating value, or therm value.

The calorific bulk of accustomed gas can be acquired application a action gas chromatograph, which measures the bulk of anniversary basic of the gas, namely:

methane

ethane

carbon dioxide

water

Additionally, to catechumen from aggregate to thermal energy, the burden and temperature of the gas have to be taken into consideration. Burden is about not a problem; the beat is artlessly installed anon after of a burden regulator and is calibrated to apprehend accurately at that pressure. Burden advantage again occurs in the utility's announcement system. Varying temperature cannot be handled as easily, but some meters are advised with congenital temperature advantage to accumulate them analytic authentic over their advised temperature range. Others are adapted for temperature electronically.

Remote readouts

Remote account is acceptable accepted for gas meters. It is generally done through an cyberbanking beating achievement army on the meter. There are altered styles accessible but a lot of accepted is a acquaintance cease switch.

Flow measurement calculations

Turbine, rotary and diaphragm meters can be compensated application a adding defined in American Gas Association Report No. 7. This standardised adding compensates the abundance of aggregate as abstinent to abundance of aggregate at a set of abject conditions. The AGA 7 adding itself is a simple arrangement and is, in essence, a body alteration access to advice the aggregate or amount of gas at abounding altitude to a aggregate or amount at abject conditions.

Orifice meters are a actual frequently acclimated blazon of meter, and because of their boundless use, the characteristics of gas breeze through an breach beat accept been carefully studied. American Gas Association Report No. 3 deals with a ample ambit of issues apropos to breach metering of accustomed gas, and it specifies an algorithm for artful accustomed gas breeze ante based on the cogwheel pressure, changeless burden and temperature of a gas with a accepted composition.

These calculations depend in allotment on the ideal gas law and aswell crave a gas compressibility adding in adjustment to annual for the actuality that absolute gases are not ideal. A actual frequently acclimated gas compressibility adding is American Gas Association Report No. 8, detail characterization.