Natural Gas Meter Types Including Residential Gas Meters
There are eight natural gas meter types, four use traditional, while four use new gas technology. Each has benefits. The meters are used in industrial applications and natural gas distribution. While we mention some of the industrial purposes, the focus of this post regards natural gas distribution from residential gas meters to high-pressure applications.
What are the four traditional gas technology meters?
- Positive displacement (diaphragm meter, rotary meter)
- Turbine meter
- Differential pressure (∆P) (orifice plates, venturi tubes)
- Rotameter (variable area (VA))
Positive Displacement Meters
In a diaphragm meter, the gas or fluid flows into the meter inlet, which has an oscillating diaphragm. The compartment fills and displaces to the outlet; each revolution of the diaphragm determines the flow rate. Diaphragm meters are used as residential gas meters, and in commercial, and light industrial applications.
Rotary Gas Meter
In a turbine meter, the volumetric flow rate is calculated based upon the angular velocity of a rotor inside the meter. This meter at times is also referred to as a velocity-type meter. A turbine meter has high turndown and good accuracy. It also has moving parts, so gas cleanliness must be considered, and it requires pressure and temperature compensation. This meter type is limited to measuring low flow rates.
As the turbine meter, the orifice plate is an inferential meter, as it infers the volumetric flow rate by measuring a property of the flow stream. An orifice meter is a differential pressure meter and infers the flow by measuring the pressure drop over an obstruction inserted in the flow. Orifice meters are a commonly accepted method of flow measurement for industrial applications; they have no moving parts and are easy to service. Unfortunately, they have limited turndown and do not handle a wide range of flow rates. They also have reduced low-flow sensitivity and require gas static pressure, differential pressure, viscosity, density, and temperature to accurately measure gas flow.
The rotameter is an industrial flow meter that measures the volumetric flow rate of fluids in a closed tube. It is a variable area meter and provides a simple, precise, and inexpensive indication of flow rates.
What are the New Technology Gas Meters?
Other newer gas meters which measure volume for residential, commercial, or industrial applications are:
Ultrasonic flowmeters measure the difference in transit time of pulses that travel from a downstream transducer to the upstream transducer, compared to the time from the upstream sensor back to the downstream transducer. This style of the meter is extremely accurate, has a high turndown ratio and excellent rangeability, but it is costly. Ultrasonic meters are usually used at pipeline meter stations in high-flow and high-pressure applications where the slightest inaccuracy can negatively impact the bottom line.
Coriolis meters provide a direct mass flow measurement based upon the deflection force of the fluid moving through a vibrating tube. These meters are very accurate with high turndown capabilities and are independent of fluid properties. They are also very expensive to purchase and install and are not suitable for larger pipe sizes.
A thermal mass flow meter is an instrument that measures gas mass flow. The device is used in many industrial applications.
Vortex meters are a latecomer to API approval for custody transfer of natural gas. This late approval has made it difficult for the meter to catch up to other custody transfer meters. Consequently, vortex meters are primarily in industrial markets with very little custody transfer of natural gas usage.
What are the six custody transfer meter types for natural gas?
- Differential pressure meters
- Turbine meters
- Positive displacement meters
- Coriolis flowmeters
- Ultrasonic meters
- Vortex flowmeters
Gas meters measure gas volume, though they do not take into account the quality of the gas, which impacts the heat value and is subsequently adjusted in the billing cycle, and known as the therm value. Pressure and temperature compensation are required to convert gas volume to thermal energy. At times electronic correction is also needed.
Need a Natural Gas Meter?
Linc Energy Systems is the stocking distributor for Itron gas meters and regulators. Not familiar with Itron? Itron was formerly Actaris and Schlumberger.
We also sell thermal mass flow meters and gas analyzers, found on gas meters and flow meters.