In order to provide a method of manufacturing a thermal type flowmeter that is capable of reducing deformation of a semiconductor chip, which is caused by molding, a method of manufacturing a thermal type flowmeter is provided that includes a circuit package of a resin-molded semiconductor chip. The method includes resin-molding the semiconductor chip in a state in which a mold is pressed against a heat transfer surface that is provided on a surface of the semiconductor chip and a pressed surface that is set on the surface of the semiconductor chip at a position separate from the heat transfer surface.

A physical quantity measurement device includes a housing forming a through flow path, and a measurement flow path branching from the through flow path. A physical quantity sensor is provided in the measurement flow path. An inner surface of the housing includes an inlet ceiling surface and an inlet floor surface which face each other and define an inlet through path that is between and connects an inlet of the through flow path and an inlet of the measurement flow path, The inlet ceiling surface includes a ceiling inclined surface that extends from the inlet of the through flow path and is inclined with respect to the inlet floor surface. A distance between the ceiling inclined surface and the inlet floor surface gradually decreases in a direction from the inlet of the through flow path toward an outlet of the through flow path.

A flow sensing module is provided for determining a flow rate of a fluid flowing through a flow channel. The flow sensing module may include an integrated flow restrictor, sometimes including a plurality of concentric ribs defining a plurality of orifices shaped to match the curvature of the wall of the flow channel. A first sensing port may open into the flow channel upstream of the flow restrictor, and a second sensing port may open into the flow channel downstream of the flow restrictor. A flow rate of a fluid flowing through the flow channel may be determining using a differential pressure between the first and second ports created by the flow restrictor, either using a flow sensor or a pressure sensor. The particular arrangement and relative dimensions of the orifices of the flow restrictor and the pressure ports can result in substantially reduced noise.

The present invention has been made to improve measurement accuracy of a thermal flow meter. In the thermal flowmeter 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).

Provided is a physical quantity detection device capable of improving noise performance of a flow rate detection unit as compared with the related art. The physical quantity detection device 20 includes a plate-like chip package 208 that is arranged to protrude from the flow path of the measurement target gas and has a width W along the flow direction of the measurement target gas. The chip package 208 includes a flow rate detection unit 205, an accelerating flow path 208c, a measurement surface 208a, a non-measurement surface 208b, and a separation flow portion 208d. The cross sectional area of the accelerating flow path 208c is reduced, and the flow rate detection unit 205 is arranged. The separation flow portion 208d partitions the second sub-passage 234b into a measurement flow path facing the measurement surface 208a and a non-measurement flow path facing the non-measurement surface 208b. In the width direction Dw of the chip package 208, the end portion 208ce of the accelerating flow path 208c and the end portion 208de of the separation flow portion 208d are separated from each other.

A flow sensor includes an auxiliary channel having an opening into which a fluid to be measured is taken; a sensor element that measures the flow of the fluid to be measured; a housing that accommodates electronic parts; and a resin cover. The flow sensor is configured such that junctions of the housing and the cover are formed in locations where first target weld portions, which are formed so that the circuit chamber is surrounded, face each other and second target weld portions, which are disposed for additional reinforcement of the joints, face each other on a bonding face of the housing and a bonding face of the cover with a step being provided. The positioning of the housing and the cover is determined, and the first target weld portions are welded to each other and second target weld portions are welded to each other by way of laser radiation.

A flow rate sensor includes: a housing made from a resin material and having a bottom base portion and a side wall, at least one surface side of the housing being open; a cover made from a resin material, covering the one surface side of the housing, welded to an upper surface of the side wall of the housing, and defining, with the bottom base portion and the side wall of the housing, an auxiliary passage within which a gas to be measured flows that is taken in from a main passage; and a flow rate detection unit disposed within the auxiliary passage. A protruding portion for height control is provided to one of the housing and the cover at least in a vicinity of the side wall around the flow rate detection unit so as to suppress sinking in of the cover during welding.

The present invention provides a thermal flowmeter having good measurement accuracy by reducing deviation in the flow velocity distribution of a gas under measurement flowing through an auxiliary passage. An auxiliary passage 330 for taking in a portion of a gas under measurement IA flowing through a main passage 124 has a curved passage 32a that bends toward a flowrate measurement element 602. The curved passage 32a has a resistance portion 50 formed therein that applies resistance to the flow of the gas under measurement IA flowing through the outer peripheral side CO of the curved passage 32a so that the pressure loss of the gas under measurement IA flowing through the outer peripheral side CO is high compared to that of the gas flowing through the inner peripheral side CI of the curved passage 32a.

A connection terminal is on a flange of a thermal flow meter. A terminal connection part has a first and a second bent part. The first bent part is bent from a first direction to a second direction. The second bent part has is bent from the first bent part to a third direction. The first and second bent parts are formed such that when connection pin parts of a plurality of the connection terminals and terminal connection parts of the plurality of connection terminals are projected onto a first imaginary plane, an imaginary line L extending along a first direction passing through the projection areas of each of the terminal connection parts of the plurality of connection terminals passes between the projection areas of the connection pin parts from among the connection pin parts of the plurality of connection terminals, that are positioned on both sides.

A system for metering gas includes a flow sensor and a controller. The flow sensor is disposed in a conduit in fluid connection with a flow of a gas through the conduit. The flow sensor includes a heater and a temperature sensing element, and generates an electrical output based on the flow of the gas. The controller controls operation of the heater and is operable in a pre-measurement mode and multiple measurement modes. The controller in the pre-measurement mode operates the heater at a pre-measurement setting. The controller in the measurement modes operates the heater at corresponding measurement settings that have increased power levels and/or increased operating durations relative to the pre-measurement setting. The controller in the measurement modes is configured to determine a flow rate of the gas based on an amplitude characteristic and/or a temporal characteristic of the electrical output of the flow sensor.