An object of the present invention is to provide a physical quantity detection device configured to reduce an influence of a resonance phenomenon of sound pressure on flow rate characteristics. The physical quantity detection device according to the present invention includes: a housing arranged in the main passage; a sub-passage arranged in the housing; a flow rate detection unit arranged in the sub-passage; a circuit unit electrically connected to the flow rate detection unit; a circuit chamber arranged in the housing and accommodating the circuit unit; and a first introduction passage including one end open to the sub-passage and the other end open to the circuit chamber to communicate between the sub-passage and the circuit chamber. The flow rate detection unit includes a diaphragm including a diaphragm front surface exposed to the sub-passage and a diaphragm rear surface exposed to a closed chamber that communicates with the circuit chamber, and the circuit chamber includes at least one or more protrusions arranged opposite an opening to which the other end of the first introduction passage is open.

The present invention has been made to improve measurement accuracy of a thermal flow meter. In the thermal flow meter according to the invention, a circuit package (400) that measures a flow rate is molded in a first resin molding process. In a second resin molding process, a housing (302) having an inlet trench (351), a bypass passage trench on frontside (332), an outlet trench (353), and the like are formed through resin molding, and an outer circumferential surface of the circuit package (400) produced in the first resin molding process is enveloped by a resin in the second resin molding process to fix the circuit package (400) to the housing (302).

A flow sensor structure seals the surface of an electric control circuit and part of a semiconductor device via a manufacturing method that prevents occurrence of flash or chip crack when clamping the semiconductor device via a mold. The flow sensor structure includes a semiconductor device having an air flow sensing unit and a diaphragm, and a board or lead frame having an electric control circuit for controlling the semiconductor device, wherein a surface of the electric control circuit and part of a surface of the semiconductor device is covered with resin while having the air flow sensing unit portion exposed. The flow sensor structure may include surfaces of a resin mold, a board or a pre-mold component surrounding the semiconductor device that are continuously not in contact with three walls of the semiconductor device orthogonal to a side on which the air flow sensing unit portion is disposed.

The purpose is to improve the measurement accuracy of a thermal air flow meter. The device has: an auxiliary passage for entraining a portion of a fluid being measured; a sensor chip arranged in the auxiliary passage, for measuring the flow rate of the fluid being measured; an electronic component having an internal resistor, for converting the fluid flow rate detected by the sensor chip to an electrical signal; and a substrate on which the sensor chip and the electronic component are mounted. The substrate is covered by a filler material, on the surface of which the electronic component is mounted.

The present invention addresses the problem of obtaining a thermal flow meter capable of reducing a pulsation error by preventing a discharge port and a main outlet from being blocked by a vortex during a transient period and reducing a difference between flow speed distributions in normal and pulsation states. This thermal flow meter is provided with a housing disposed in a main passage; and a sub passage provided in the housing. In addition, in the housing, a first outlet and a second outlet of the sub passage are disposed in a downstream end portion of the housing, and a curved surface section is provided adjacent to the first and second outlets.

The sensor device (100; 200) for a device (10) for weathering or lightfastness testing of samples comprises a sensor housing (110) which is adapted to be arranged in a weathering chamber (1) of the device (10) in the same manner as a sample (3), and an air mass sensor (120; 220) which comprises a sensor element (120.2; 220.2) and is attached to the sensor housing (110) in such a manner that the sensor element (120.2; 220.2) is adapted to be mounted on the sensor housing (110.2; 220.2) and attached to the sensor housing (110) such that the sensor element (120.2; 220.2) is exposed in the same manner as a sample (3) to an air flow prevailing in the weathering chamber (1).

A sensor body contains a sensor element in a body recess opened at a body opening. A sensor substrate has a mounting surface on which a circuit element for processing a detection signal is mounted and holds the sensor body on the mounting surface. A sensor cover has a cover window penetrating between an intake passage and the body opening and covers the sensor body. A sensor filter is interposed between the sensor body and the sensor cover. A potting resin body is cured on the mounting surface so as to seal the circuit element. The sensor cover is embedded in the potting resin body on the outer peripheral side of the sensor body.

The disclosure relates to a sensor apparatus and a method for measuring the flow rate of a shielding gas in a welding apparatus. The sensor apparatus comprises at least one inlet and at least one outlet in fluid connection with one or more bypass channels and with one or more sensor channels, and at least one input hose and one output hose. The apparatus also comprises one or more thermal mass flow sensors connected to the one or more sensor channels, and a control unit configured to retrieve sensor responses from the one or more thermal mass flow sensors and to determine the flow rate of the shielding gas through the sensor apparatus based on the retrieved sensor response and calibration data, wherein the calibration data comprises one or more characteristic curves comprising gas flow values and sensor response values. The control unit is configured to retrieve from a memory unit: the composition of the shielding gas; the number of active thermodynamic degrees of freedom which the molecules of each gas component in the shielding gas possess at the retrieved shielding gas temperature; a characteristic curve for each gas component separately, which consists of sensor response data as a function of gas flow rate, measured in a calibration experiment conducted with a pure gas consisting only of that gas component. The control unit is configured to calculate a new, mixture-specific characteristic curve for the gas mixture as a weighted average of the pure-gas characteristic curves, wherein the weight assigned to each value on a pure-gas characteristic curve is a product of the concentration percentage of that gas component in the shielding gas mixture and the number of active thermodynamic degrees of freedom which the molecules of that gas component possess at the retrieved shielding gas temperature; and to use the mixture-specific characteristic curve as the characteristic curve for the shielding gas mixture by retrieving from this characteristic curve the calibration gas flow rate which corresponds most closely to the retrieved new sensor response; and to identify this flow rate as the current flow rate of the shielding gas through the sensor apparatus. The sensor apparatus also comprises a display unit configured to display the determined flow rate of the shielding gas to a user and/or a memory unit for storing the determined flow rate of the shielding gas.

A method for measuring a flow of a fluid in a tube includes heating the fluid in the tube with a heating element. A first signal is measured with a first temperature sensing element at a first location. A second signal is measured with a second temperature sensing element at a second location. At least one temperature signal is calculated based on the first signal and the second signal. The at least one temperature signal includes a difference temperature signal and a sum temperature signal. The difference temperature signal is calculated based on a difference between the second signal and the first signal. The sum temperature signal is calculated based on a sum of the second signal and the first signal. The flow is derived based on the difference temperature signal, the sum temperature signal, or a combination thereof.

A physical quantity measurement device that measures a physical quantity of a fluid includes a bypass flow channel through which a fluid flows, a physical quantity detection unit for detecting a physical quantity of the fluid in the bypass flow channel, a detection unit having a detection terminal electrically connected to the physical quantity detection unit, a housing having a flow channel forming portion having an insulating property and forming a bypass flow channel and a terminal accommodating portion having an insulating property and accommodating a detection terminal, and a ground portion connecting the flow channel forming portion to a ground. A volume resistivity of the flow channel forming portion is included in the range of 1.010.sup.11 (1.010 to the 11th power) cm to 1.010.sup.14 (1.010 to the 14th power) cm.