Abstract: An ultrasonic flowmeter includes a measurement flow path and a pair of ultrasonic sensors arranged upstream and downstream on a first surface of the measurement flow path. In addition, the ultrasonic flowmeter includes a flow rate calculator that detects a flow rate of a fluid to be measured based on a propagation time until ultrasonic signals transmitted from one of the ultrasonic sensors propagate with one or more reflections on a second surface of the measurement flow path facing the first surface, and are received by the other one of the ultrasonic sensors. Furthermore, the measurement flow path has an inner wall surface provided with a draft of a mold for integral molding, and the ultrasonic sensors are fixed to the measurement flow path, incident angles of ultrasonic signals transmitted from the ultrasonic sensors on reflection surface of the second surface where the ultrasonic signals are reflected being equal.

Abstract: An ultrasonic flowmeter includes flow path that has a rectangular cross section and through which a fluid to be measured flows, and partition plate that divides flow path into measurement flow path and non-measurement flow paths. In addition, the ultrasonic flowmeter includes a pair of ultrasonic sensors that are arranged upstream and downstream of a surface forming flow path and transmitting and receiving ultrasonic signals, and a flow rate calculator that detects a flow rate of the fluid to be measured based on a propagation time. The ultrasonic flowmeter includes openings that connect measurement flow path, non-measurement flow paths, and a space where the ultrasonic sensors is located, and the ultrasonic sensors mainly propagate ultrasonic waves only to measurement flow path through openings.

Abstract: An ultrasonic flow meter includes measurement flow path where a cross section of a flow path through which a fluid to be measured flows is rectangular, one or more partition plates that divide measurement flow path into a plurality of layered flow paths, and a pair of ultrasonic sensors that are disposed upstream and downstream on the layered flow paths and are capable of transmitting and receiving an ultrasonic signal. In addition, the ultrasonic flow meter includes a flow rate measuring unit that detects a flow rate of the fluid to be measured based on a propagation time, the propagation time being a time period from when one of the ultrasonic sensors transmits the ultrasonic signal to cause the ultrasonic signal to propagate through the fluid to be measured until when an other one of the ultrasonic sensors receives the ultrasonic signal.

Abstract: A gas safety device includes: flow path through which a gas flows; ultrasonic sensor for measuring a flow rate of the gas flowing through flow path; flow rate calculator that calculates a flow rate measurement data pieces from a measurement value of the flow rate measured by ultrasonic sensor; and leakage detector that detects a minor leakage of the gas. The gas safety device further includes: pulsation recognizer that recognizes that pulsation is occurring when a fluctuation in the flow rate measuring data pieces calculated by flow rate calculator is greater than or equal to a predetermined value; and pulsating flow rate corrector that corrects, when pulsation recognizer determines that the pulsation is occurring, the flow rate measurement data piece by a predetermined value. Furthermore, when pulsation recognizer determines that the pulsation is occurring, leakage detector determines whether a leakage is present using the flow rate measurement data piece corrected by pulsating flow rate corrector.

Abstract: An ultrasonic flowmeter includes flow path that has a rectangular cross section and through which a fluid to be measured flows, and partition plate that divides flow path into measurement flow path and non-measurement flow paths. In addition, the ultrasonic flowmeter includes a pair of ultrasonic sensors that are arranged upstream and downstream of a surface forming flow path and transmitting and receiving ultrasonic signals, and a flow rate calculator that detects a flow rate of the fluid to be measured based on a propagation time. The ultrasonic flowmeter includes openings that connect measurement flow path, non-measurement flow paths, and a space where the ultrasonic sensors is located, and the ultrasonic sensors mainly propagate ultrasonic waves only to measurement flow path through openings.

Abstract: An ultrasonic flow meter includes measurement flow path through which a fluid to be measured flows, and first ultrasonic sensor and second ultrasonic sensor that are disposed upstream and downstream in a first surface on measurement flow path and are capable of transmitting and receiving an ultrasonic signal. In addition, the ultrasonic flow meter includes a flow rate calculator that detects a flow rate of the fluid to be measured based on a propagation time, the propagation time being a time period from when the first ultrasonic sensor transmits the ultrasonic signal to cause the ultrasonic signal to propagate through the fluid to be measured and be reflected on a second surface facing the first surface at least once until when the second ultrasonic sensor receives the ultrasonic signal.

Abstract: An ultrasonic flowmeter includes measurement flow path and a pair of ultrasonic sensors arranged upstream and downstream on a first surface of measurement flow path. In addition, the ultrasonic flowmeter includes a flow rate calculator that detects a flow rate of a fluid to be measured based on a propagation time until ultrasonic signals transmitted from one of the pair of ultrasonic sensors propagate with one or more reflections on a second surface of measurement flow path facing the first surface, and are received by another one of the pair of ultrasonic sensors. Furthermore, measurement flow path has an inner wall surface provided with a draft of a mold for integral molding, and the pair of ultrasonic sensors are fixed to measurement flow path, incident angles of ultrasonic signals transmitted from the pair of the ultrasonic sensors on reflection surface of the second surface where the ultrasonic signals are reflected being equal.

Abstract: An ultrasonic flow meter includes measurement flow path where a cross section of a flow path through which a fluid to be measured flows is rectangular, one or more partition plates that divide measurement flow path into a plurality of layered flow paths, and a pair of ultrasonic sensors that are disposed upstream and downstream on the layered flow paths and are capable of transmitting and receiving an ultrasonic signal. In addition, the ultrasonic flow meter includes a flow rate measuring unit that detects a flow rate of the fluid to be measured based on a propagation time, the propagation time being a time period from when one of the ultrasonic sensors transmits the ultrasonic signal to cause the ultrasonic signal to propagate through the fluid to be measured until when an other one of the ultrasonic sensors receives the ultrasonic signal.

Abstract: Provided is a gas safety device including: flow path for flowing gas; flow rate measurement unit for measuring a flow rate of the gas flowing through flow path; absolute pressure sensor disposed inside flow path to measure an absolute pressure of the gas; absolute pressure sensor disposed outside flow path to measure an absolute pressure of atmospheric pressure; and gas pressure determination unit that measures a change in gas supply pressure from the absolute pressure of the gas and the absolute pressure of the atmospheric pressure measured by absolute pressure sensor and absolute pressure sensor, respectively. The gas safety device further includes shutoff valve that shuts off flow path, and control circuit that controls flow rate measurement unit and that causes shutoff valve to shut off flow path when determining abnormality from the flow rate of the gas measured by flow rate measurement unit or the change in gas supply pressure measured by gas pressure determination unit.

Abstract: A gas safety device includes: flow path through which a gas flows; ultrasonic sensor for measuring a flow rate of the gas flowing through flow path; flow rate calculator that calculates a flow rate measurement data pieces from a measurement value of the flow rate measured by ultrasonic sensor; and leakage detector that detects a minor leakage of the gas. The gas safety device further includes: pulsation recognizer that recognizes that pulsation is occurring when a fluctuation in the flow rate measuring data pieces calculated by flow rate calculator is greater than or equal to a predetermined value; and pulsating flow rate corrector that corrects, when pulsation recognizer determines that the pulsation is occurring, the flow rate measurement data piece by a predetermined value. Furthermore, when pulsation recognizer determines that the pulsation is occurring, leakage detector determines whether a leakage is present using the flow rate measurement data piece corrected by pulsating flow rate corrector.