Provided is a thermal flow meter to improve the measurement accuracy of a temperature detector provided in a thermal flow meter. The thermal flow meter includes a bypass passage through which a measurement target gas 30 flowing through a main passage flows, and a circuit package 400 which includes a measurement circuit for measuring a flow rate of the measurement target gas 30 flowing through the bypass passage and a temperature detecting portion 452 for detecting a temperature of the measurement target gas. The circuit package 400 includes a circuit package body which is molded by a resin to internally envelope the measurement circuit and a protrusion 424 molded by the resin. The temperature detecting portion 452 is provided in the leading end portion of the protrusion 424, and at least the leading end portion of the protrusion protrudes to the outside from a housing 302.

A fluid monitoring system is provided, which includes a control unit and at least one fluid pressure recorder. The recorder is configured for direct connection to a pipeline portion of a system to be monitored and includes upstream and downstream pressure sensors. The control unit is configured to detect, and provide for display or trigger an action, in the event that a new downstream pressure is more than a threshold number of standard deviations above or below a mean downstream pressure determined from prior readings of the downstream pressure—even though neither the minimum nor maximum pressure of the pipeline portion is reached. A fluid monitoring system for a regulator on a pipeline system is also provided.

A gas meter is provided. The gas meter has a gas inlet, a gas outlet and a measuring section. A measuring device for thermal flow measurement can be arranged in the measuring section. A filtering device for removing particulate impurities is arranged downstream of the gas inlet. Gas diverted from the main gas flow is supplied to the filtering device for purifying the gas. After the purification, the purified gas is fed to the measuring device arranged downstream of the filtering device.

Provided is a thermal flow meter that can be prevented from being eroded due to adhesion of water or like to a cut end portion of the lead exposed from the mold resin of the circuit package. A thermal flow meter 300 of the present invention is a thermal flow meter having a circuit package 400 formed by mounting a detection element 518 on leads 544 and 545 supported by a support frame 512, sealing with a mold resin, and cutting off the support frame 512, wherein cut end portions 544a and 545a of the leads 544 and 545 exposed from the mold resin of the circuit package 400 by cutting off the support frame 512 is covered by a covering portion 371.

A thermal air flow sensor that offers high flow rate measurement accuracy is provided. The thermal air flow sensor includes a measuring element. The measuring element includes: a semiconductor substrate; a heating resistor and a temperature measuring resistor both formed as a result of thin films being stacked over the semiconductor substrate; an electronic insulator including a silicon oxide film; and a diaphragm portion formed after part of the semiconductor substrate is removed. The heating resistor and the temperature measuring resistor are formed over the diaphragm portion. In the thermal air flow sensor, a ratio of an area occupied by the thin films to an area of the measuring element ranges between 40% and 60%.

A decrease in the accuracy after switching of the heating state can be reduced. The physical quantity detecting device includes: a flow rate detecting unit configured to include a heating element to measure a flow rate of a fluid to be measured; a heating element control unit configured to switch a control state of the heating element to any one of a heating state and a heating suppression state; and a signal processing unit configured to process a measured value of the flow rate detecting unit. When the heating element control unit switches the control state, the signal processing unit processes an estimated value determined based on a measured value of the flow rate detecting unit before the switching for a predetermined period immediately after the switching.

Provided is a thermal type flowmeter in which contamination of a sensor element is reduced. The flowmeter includes a sensor element including a heating resistor formed in a thin film part, the thin film part being provided on a diaphragm formed on a substrate; a support member to locate the sensor element thereon; a secondary channel that includes part of the support member and takes in part of intake air flowing through an air intake pipeline; and a guide member provided on the support member or the sensor element that lies on a line L that extends along an air flow in the secondary channel and passing over the thin film part, the guide member allowing fine particles to be guided in a direction away from the line L, the fine particles coming together with an air flow along the surface of the support member or the sensor element.

To improve measurement stability of a flow rate detection unit in a physical quantity detection device, a periphery of a synthetic resin material is provided with a protruding section protruding to a cover side. A physical quantity detection device includes a housing, a front cover fixed to the housing, a circuit board housed in the housing, a flow rate detection unit that detects, in a sub-path, the flow rate of a gas to be measured by being attached to the circuit board, a connecting wire that electrically connects the flow rate detection unit to the circuit board, and a synthetic resin material that seals a connecting wire-included connection portion between the circuit board and the flow rate detection unit, the front cover having a protruding section covering at least a part of the synthetic resin material by protruding into the sub-path.

A mass airflow sensor according to the present disclosure includes a housing, a sensor element, and a flow deflector. The housing defines an airflow passage configured to receive air flowing in a first direction. The sensor element is disposed in the airflow passage and generates a signal indicating a mass flow rate of air flowing through the airflow passage. The flow deflector is disposed in the airflow passage downstream of the sensor element, extends from an inner wall surface of the airflow passage, and is configured to inhibit air flow through the airflow passage in a second direction that is opposite of the first direction.

In order to provide a thermal flow meter for improving workability of a flow rate measurement device having a temperature measurement function for the measurement target gas and measurement accuracy for measuring a temperature, the thermal flow meter is structured such that a flow rate measurement circuit package having a protrusion for measuring a gas temperature is formed through resin molding. An inlet port opened to the upstream side of the measurement target gas is formed, a protrusion is arranged inside the inlet port, an inlet port and an outlet port are formed in the front and rear covers along the protrusion, and the measurement target gas received from the inlet port flows along the protrusion. Since the measurement target gas subjected to the measurement flows along the protrusion, it is possible to reduce influence of the heat from other heat resources and improve measurement accuracy.