Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Verification bench based on a centrifugal fan with variable speed for gas flow meters
Submission Author:
Luciano Amaury dos Santos , SC
Co-Authors:
Luciano Amaury dos Santos
Presenter: Luciano Amaury dos Santos
doi://10.26678/ABCM.COBEM2023.COB2023-0727
Abstract
This work presents a bench, based on the use of a centrifugal fan commanded through a frequency inverter, for verifying gas flow meters. The gas meters usually have at least one “low frequency sensor”, that at the end of the operational flow range switches below 1 Hz, and sometimes have also a “high frequency sensor” that switches above 1 kHz. This work also describes briefly a simple electronic circuit for detecting this switching and pieces of software needed to turn this switching in flow information, as well to gather pressure information and to change the fan speed when demanded. The most usual way of performing gas flow meter verifications is by the use of a reference meter mounted in series (traversed by the same air flow) with the meter to be verified. It was observed, however, that the response of a turbine type gas meter to the flow caused by a radial fan spinning at the same speed and blowing air in the same bench (a short pipe with the pressure sensor installed) is repetitive to a degree that allows the recording of the response of the reference gas meter and then its comparison to the response of other gas meters to be verified (at least if they are of the same model) dismissing the use of two gas meters in series. Further investigation also showed that a characteristic surface of the bench (the pressure head it supplies as a function of the air volumetric flow rate and the fan speed) could be used in this verification process (the characteristic surface obtained with a certain model of reference gas meter can be used to other models of gas meters to be verified, without putting them in series). The proposed bench has a relatively low cost (the most expensive component is the radial fan, and it is cheaper than a gas meter) and the discussion of its advantages and disadvantages, in light of the experimental results obtained and of what is known of other verification systems commercially available, is a valuable one.
Keywords
flow measurement, Verification, Gas natural, Radial fan
