MEMS utility meters with integrated mass flow sensors

摘要

This invention is related to an apparatus which incorporates a microfabricated silicon mass flow sensor to measure city gas flow rate in a medium pressure range for utility industry which is dominated by conventional mechanical meters such as turbine and rotary meters. The microfabricated mass flow sensor is so called micro-electro-mechanical systems (a.k.a. MEMS) device. Due to the small feature size of micro scale for MEMS mass flow sensor, the invented apparatus includes many advantages such as low power consumption, compact package, high reliability and extended dynamic measurement range. This apparatus is also provided with a stable flow conditioning to achieve a desired dynamic range capability. Furthermore, because of the high accuracy characteristic, the apparatus in this invention could be applied for custody transfer or tariff in utility industry as well.

主权项

1. A utility gas meter comprising:
a gas sensor probe assembly consisting of a sensing flow channel which is formed by a sensing flow channel top cover and a sensing flow channel bottom base, a MEMS thermal mass flow sensor which is carried by a first printed circuit board, and a connector body which is used to connect the first printed circuit board (carried the MEMS thermal mass flow sensor) and a second printed circuit board to control the MEMS thermal mass flow sensor; wherein the sensing flow channel has a diameter of one fourth to one eighth of inner diameter of the flow channel; wherein the first printed circuit board is secured on the sensing flow channel bottom base; and wherein the second printed circuit board is equipped with a memory chip to collect measurement data; a gas meter body consisting of a flow channel, two flow conditioners and two metal flange for gas pipe connection; wherein portion of the flow channel is a Venturi structure and the gas sensor probe assembly is inserted into the Venturi structure and positioned at a location with narrowest pipe inner diameter along the flow channel direction; and wherein the position of the MEMS thermal mass flow sensor is placed at the center along the direction which is perpendicular to the flow channel; and a gas meter head consisting of a front chamber and a back chamber; wherein the front chamber is utilized to house a display, a display control circuit board, and a main circuit board; wherein the back chamber is utilized to house a battery, and a battery control circuit board.