Diaphragm Gas Flow Meters
The most commonly used type of gas flow meter is the diaphragm or bellow meter. The meter uses a set of diaphragms which move along an axis in a horizontal or vertical orientation.
Gas flows into this chamber, and then back out again. Each time it moves, the diaphragms part. When the diaphragms move, a system of gears is set in motion, which operates a counter. Each time the diaphragms expand and contract, a number is rotated on the counter.
In this way, a gas company can see how much gas a home or business is using.
Rotary Gas Flow Meter
The rotary gas flow meter makes use of propellers to transfer gas. These propellers spin opposite one another. With each rotation, a specific amount of gas can be transfered. The propellers are connected to a shaft that is connected to a mechanical counting
mechanism. In most rotary flow meters, the counter translates each shaft rotation into a number corresponding to the amount of gas flow for each rotation. Typically, these meters are used on larger industrial applications where large volumes of gas are being transferred as in city gas pipelines.
Coriolis Gas Flow Meter
The Coriolis meter is a little more complex in nature. They take into account the Coriolis effect of gravitation pull and fluid or gas movement. Two parts of the meter vibrate together inside the pipe, and the rate of vibration corresponds to the overall density of the contents in the pipe. When gas flows, the density changes, and the Coriolis effect changes the vibration of one of the parts of the meter. This vibration difference is translated into a precise reading by electronic measuring devices inside the meter.
Ultrasonic Gas Meters
Another type of flow meter is the ultrasonic meter. It is used to determine the amount of gas flowing in large industrial applications. The meter does not have a mechanical turbine or diaphragm. It measures the speed of sound waves traveling through the pipe, from one point to another. The results are determined through advanced sonic measuring devices in the meter. Many of these meters use four separate sound waves to take an average density of gas in the pipe. Since sound travels at different speeds in different volumes of gas a reading can be generated to a high accuracy. These gas flow meters do require very advanced computations, so advanced computers are a part of the meter.
Thermal Mass Gas Meters
Another type of flow meter is the Thermal Mass meter. It is used to determine the amount of gas flowing in large industrial applications. The meter does not have a mechanical turbine or diaphragm. It measures on The Heat Transfer Principle, from one point to another. The results are determined through advanced devices in the meter. These gas flow meters do require very advanced computations, so advanced computers are a part of the meter.