Gas meter and center device are provided. Gas meter includes flow rate measurer that measures a flow rate of gas in time series. Center device receives and analyzes flow rate data from gas meter, and monitors states of use of gas appliances. Gas meter detects the start of operation of gas appliances, and transmits flow rate data during predetermined periods before and after the start of operation in accordance with a request from center device. Center device monitors the states of use of gas appliances based on the received flow rate data.

A processing chamber gas detection system is provided, including a chamber, an exhaust pipe, a connection pipe, and a gas detector. The chamber is configured to perform a chemical vapor deposition (CVD) process. The exhaust pipe is connected to the chamber and the pumping unit, and the connecting pipe communicates with the exhaust pipe. The gas detector is disposed on the connecting pipe and configured to detect the oxygen content in the air from the chamber. When the air in the chamber is pumped out via the pumping unit and the air flows through the exhaust pipe and the connecting pipe, the gas detector detects whether oxygen is contained in the air or not.

A processing chamber gas detection system is provided, including a chamber, an exhaust pipe, a connection pipe, and a gas detector. The chamber is configured to perform a chemical vapor deposition (CVD) process. The exhaust pipe is connected to the chamber and the pumping unit, and the connecting pipe communicates with the exhaust pipe. The gas detector is disposed on the connecting pipe and configured to detect the oxygen content in the air from the chamber. When the air in the chamber is pumped out via the pumping unit and the air flows through the exhaust pipe and the connecting pipe, the gas detector detects whether oxygen is contained in the air or not.

A gas meter system includes a gas meter, a gas production plant, and a center device. The gas meter includes a sound velocity derivation unit configured to derive a sound velocity of a gas supplied to a demand place. The gas production plant includes: a gas production unit configured to produce the gas; and a gas characteristic identification unit configured to identify a gas characteristic representing a relationship between the sound velocity and a heating value of the gas based on an analysis result of a component of the gas produced by the gas production unit. The center device includes a gas heating value derivation unit configured to derive the heating value of the gas passing through the gas meter based on the derived sound velocity of the gas, and on the gas characteristic identified by the gas characteristic identification unit of the gas production plant.

A gas meter system includes a gas meter, a gas production plant, and a center device. The gas meter includes a sound velocity derivation unit configured to derive a sound velocity of a gas supplied to a demand place. The gas production plant includes: a gas production unit configured to produce the gas; and a gas characteristic identification unit configured to identify a gas characteristic representing a relationship between the sound velocity and a heating value of the gas based on an analysis result of a component of the gas produced by the gas production unit. The center device includes a gas heating value derivation unit configured to derive the heating value of the gas passing through the gas meter based on the derived sound velocity of the gas, and on the gas characteristic identified by the gas characteristic identification unit of the gas production plant.

A heating value derivation device includes a sound velocity derivation unit configured to derive a sound velocity of a gas flowing through a gas flow path, and a heating value derivation unit configured to refer to correspondence relationship information to derive a heating value per unit volume of the gas.

A heating value derivation device includes a sound velocity derivation unit configured to derive a sound velocity of a gas flowing through a gas flow path, and a heating value derivation unit configured to refer to correspondence relationship information to derive a heating value per unit volume of the gas.

The present invention discloses an online method for metering performance of a diaphragm gas meter. A magnetic turntable in an electromechanical conversion device is reasonably segment and motion information of each segment is recorded and analyzed. Every time when the diaphragm gas meter discharges gas of a rotary volume, a rotating shaft of a meter core rotates a circle. The magnetic turntable is meshed with a driving gear output by the rotating shaft in the meter or output by the rotating shaft outside the meter to ensure that the magnetic turntable rotates a circle every time when the diaphragm gas meter discharges a rotary volume. The present invention is significant for error management of the gas meter and intelligent control and gas utilization safety management of a gas user.

The present invention discloses an online method for metering performance of a diaphragm gas meter. A magnetic turntable in an electromechanical conversion device is reasonably segment and motion information of each segment is recorded and analyzed. Every time when the diaphragm gas meter discharges gas of a rotary volume, a rotating shaft of a meter core rotates a circle. The magnetic turntable is meshed with a driving gear output by the rotating shaft in the meter or output by the rotating shaft outside the meter to ensure that the magnetic turntable rotates a circle every time when the diaphragm gas meter discharges a rotary volume. The present invention is significant for error management of the gas meter and intelligent control and gas utilization safety management of a gas user.

A gas sampling mechanism protecting an odor sensor and permeable membrane against direct exposure to the gas molecules of an external environment provides a one-way airflow, and includes an inlet chamber, a pump chamber connected to the inlet chamber, and a pump assembly connected to the pump chamber. The pump chamber can compress or evacuate air inside the pump chamber. An inlet valve is moveably arranged between the inlet chamber and the pump, and an outlet valve is movably arranged between the pump chamber and the ambient.