Abstract: A flow meter includes: a body portion comprising a main flow path wherein flows a fluid to be measured, a first branch flow portion wherein the fluid to be measured branches and flows from the main flow path, a second branch flow portion wherein the fluid to be measured, which branches and flows from the first branch flow portion, flows into the main flow path, and narrow portions for restricting the flow of the fluid to be measured, provided in a primary flow path between the branch flow portions, a branched flow path structuring portion through which flows the fluid to be measured, connected to the branch flow portions; and a fluid measuring portion provided with a sensor disposed facing a flow path that is provided in the branched flow path structuring portion, wherein the sensor measures the fluid based on the detection results of the fluid introduced from the branch flow portions.

Abstract: A system and method of characterizing or controlling a flow of a fluid is provided that involves a sensor conduit and a bypass. A plurality of fluids may be utilized in the flow control device based on characteristic information of the device generated during calibration thereof. The characteristic information, in turn is based on a dimensionless parameters, such as adjusted dynamic pressure and adjusted Reynolds number.

Abstract: Provided are a flow meter and a flow-rate control system using the same that is capable of measuring a flow rate in a minute flow-rate region with excellent measurement accuracy by preventing or suppressing the generation of bubbles and in which accumulation of the fluid and the bubbles is less likely to occur.

Abstract: The present invention relates to a flowmeter for measuring flow rate of a fluid independently of fluid viscosity or density. In at least on embodiment, the flowmeter includes an inlet, an outlet, and a cylindrical chamber. The flowmeter also includes an impeller assembly positioned within a cylindrical chamber for rotation at a variable speed. In at least one embodiment, the flow rate of the fluid is determined when a pressure differential between the fluid in the let and fluid in the outlet becomes substantially zero.

Abstract: A secondary flow channel of a flow rate measuring device includes: a guide flow channel in which an upstream side communicates with a guide port serving as a first bifurcation point, and a downstream side serves as a second bifurcation point; a first secondary flow channel in which an upstream side is bifurcated from a guide flow channel at the second bifurcation point and formed to be parallel to a primary flow channel, and a downstream side communicates with a discharge port; a second secondary flow channel in which an upstream side is bifurcated from the guide flow channel at the second bifurcation point and formed to cross the primary flow channel; and a detection flow channel in which an upstream side communicates with a downstream side of the second secondary flow channel, a flow rate detecting element is disposed, and a downstream side communicates with the discharge port.

Abstract: An improved flow measuring device, such as a mass flow meter or mass flow controller, providing a high turn-down ratio as compared to prior art devices. In accordance with various embodiments of the invention, a flow sensor includes a sensor flow path that includes one or more restrictions configured to provide the sensor flow path with a non-linear relationship between a pressure drop across the sensor flow path and the flow of fluid through the flow sensor conduit. Such a flow sensor preferably achieves a high turn-down ratio by way of a variable bypass ratio that is directly proportional to the sensor tube mass flow rate so that the turn-down ratio of the mass flow controller will be ideally proportional to the square of the turndown achievable by the flow sensor conduit fluid sensing portion alone. In some embodiments, the restriction can be employed as a part of a fluid seal having an orifice and disposed between a flow sensor portion of a flow meter and a bypass portion of the flow meter.

Abstract: A transmitter senses flow or pressure of a process fluid in a process pipe. The process pipe may include a flow restrictor positioned therein that carries a primary flow of a process fluid. Impulse piping is configured to carry a secondary flow of the process fluid from an upstream side of the flow restrictor to a downstream side. An electro-kinetic element is positioned within the impulse piping and is configured to generate an electro-kinetic potential related to the primary flow. Measurement circuitry in the transmitter is configured to measure the electro-kinetic potential across the electro-kinetic element and relate the electro-kinetic potential to the flow of process fluid through the process pipe.

Abstract: Sensor manifolds include a housing having at least two fluid flow passages communicating with fluid entry and exit ports in the housing that are connectable in line in a full flow fluid line in a system. One or more sensor ports in the housing communicate with one or more of the flow passages for housing one or more sensors for sensing one or more characteristics, qualities or conditions of the fluid flowing through the housing without subjecting the sensor to the full fluid flow through the housing.

Abstract: A secondary flow channel of a flow rate measuring device includes: a guide flow channel in which an upstream side communicates with a guide port serving as a first bifurcation point, and a downstream side serves as a second bifurcation point; a first secondary flow channel in which an upstream side is bifurcated from a guide flow channel at the second bifurcation point and formed to be parallel to a primary flow channel, and a downstream side communicates with a discharge port; a second secondary flow channel in which an upstream side is bifurcated from the guide flow channel at the second bifurcation point and formed to cross the primary flow channel; and a detection flow channel in which an upstream side communicates with a downstream side of the second secondary flow channel, a flow rate detecting element is disposed, and a downstream side communicates with the discharge port.

Abstract: The invention generally relates to combining a plurality of flow streams. In various embodiments, a first channel transports a first laminar fluid flow, a second channel transports a second laminar fluid flow, and the first and second channels enter a merging region at an acute angle to one another along separate substantially parallel planes.

Abstract: Sensor manifolds include a housing having at least two fluid flow passages communicating with fluid entry and exit ports in the housing that are connectable in line in a full flow fluid line in a system. One or more sensor ports in the housing communicate with one or more of the flow passages for housing one or more sensors for sensing one or more characteristics, qualities or conditions of the fluid flowing through the housing without subjecting the sensor to the full fluid flow through the housing.

Abstract: The flow meter is equipped with first and second flow paths, provided in parallel and through which flows fluid having flowed through and being diverted from a main flow path, the flow diversion ratio among the first and second flow paths changing passively in accordance with the flow rate of fluid through the main flow path, and a flow rate sensor provided on at least one of the first and second flow paths. The first and second flow paths are formed, for example, as flow paths having different flow path cross-sectional areas, or alternatively are formed from mesh elements provided with mesh-free areas on a portion thereof. Alternatively, one of the either the first or second flow path is realized with a paddle mechanism incorporated therein.

Abstract: A differential pressure system and a gas meter arrangement for precisely measuring a gas consumption by a gas meter is provided. A previously known gas meter is disposed in a bypass comprising a differential pressure system in the gas pipe for measuring a volumetric flow rate inside the gas pipe. The differential pressure system includes flow ducts having decreasing diameters as the radial position increases starting from a central axis of the differential pressure system. Examples of execution include inlet ports and/or outlet ports of the flow ducts which are provided with a specific countersink angle (?), and an equidistant, concentric arrangement of flow ducts on the cross-sectional area of the differential pressure system.

Abstract: A thermal mass flow controller for controlling flow rate of a fluid includes a conduit configured to receive the fluid, a pressure sensor that measures the pressure of the fluid as the fluid flows within the conduit, a temperature sensor that measures the ambient temperature of the fluid, and a thermal sensor that generates an output representative of the flow rate of the fluid. The thermal mass flow controller further includes a control system configured to monitor the output from the thermal sensor, the pressure measured by the pressure sensor, and the ambient temperature measured by the temperature sensor, to regulate flow of the fluid within the conduit so as to compensate for a shift in the thermal sensor output caused by thermal siphoning.

Abstract: The present invention provides an air flow measuring device comprising a housing with a sub-passage having a inlet and a outlet for air flow formed in the housing, the sub-passage further having a predefined curvature with a maximum downstream point and a flow measuring element located in the sub-passage at a position at least further downstream from the point.

Abstract: Disclosed herein are systems and methods for attitude insensitive flow devices. The system can include a flow device having a processor and a computer readable medium accessible by the processor that stores a set of computer instructions executable by the processor. The computer instructions can include instructions executable to receive an orientation signal, receive a sensed flow signal, and determine a flow through the flow device based on the sensed flow signal and the orientation signal.

Abstract: An intake device for an internal combustion engine includes a restriction valve provided in an air intake path of the engine, and an air flow rate sensor for measuring the amount of air suctioned into the air intake path which is provided on the downstream side of the restriction valve. The air flow rate sensor includes an air flow path where a sensor element is provided. The air flow sensor is set in the air intake path with a predetermined angle between the axis of the air flow path and the axis of the air intake path.

Abstract: A fluid velocity sensor includes a sensor die for detecting a fluid property of a fluid flowing through a low resistance flow channel defined by a flow channel wall. One or more tap can be oriented facing into a direction of a flow stream of a fluid flowing through a flow channel defined by a channel wall, wherein the tap(s) leads to the low resistance flow channel, which directs the flow to the sensor die. At least one or more other taps can be located to face perpendicular to the direction of flow, such that the fluid after passing over the sensor die continues on a low resistance path to the other tap(s) facing perpendicular to the direction of flow in order to determine a velocity pressure based on a difference between pressures. The fluid velocity sensor can be arranged in a uni-directional or bi-directional fluid flow configuration.

Abstract: A flow detection device for detecting a flow characteristic of a fluid within a pipe is disclosed. The flow detection device includes a first channel portion that defines a first channel with an upstream aperture. The fluid can flow into the first channel through the upstream aperture. The device also includes a flow sensor disposed in the first channel, and the flow sensor detects the flow characteristic of the fluid. Furthermore, the device includes a flow straightening member that is provided upstream of the first channel. The upstream aperture is hidden by the flow straightening member as viewed looking downstream along an axis of the first channel portion. Also, the fluid flows from substantially the entire circumference of the flow straightening member into the first channel.

Abstract: A flow-velocity measuring device of a simple structure in which the size in the direction of flow of a measured fluid is small and the size of a surface area for blocking the flow of the measured fluid is small includes: an inlet port formed on a surface of a main body and opening toward the upstream of a measured fluid; an introducing channel extending in the main body from the inlet port; a branch channel branched from the introducing channel and connected at a terminal end thereof to a first discharge port opening on the surface of the main body; a discharge channel extending from the introducing channel and connected at a terminal end thereof to a second discharge port opening on the surface of the main body; and a sensor element provided in the branch channel or in a measuring channel further branched from the branch channel and connected at a terminal end thereof to a third discharge port opening on the surface of the main body, and at least any one of the discharge channel, the introducing channel, the

Abstract: Volumetric flow meters, volumetric flow controllers, mass flow meters, and mass flow controllers using a transverse laminar flow assembly are described. The flow assembly may be constructed from a plurality of open and/or closed slices or layers stacked upon one another and held together in compression by through bolts or another means. Meter or flow controller accuracy may be aided by use of flow conditioning features preceding an axial bore of the transverse flow assembly including one or more of a deflector, filter and nozzle.

Abstract: A device for determining at least one parameter of a medium flowing in a line, particularly the intake air mass of an internal combustion engine, having one part which has at least one measuring channel for conducting at least one partial flow of the medium flowing in the line in a main flow direction and which can be inserted into the line with a predetermined alignment with respect to the main flow direction, and having at least one measuring element situated in the measuring channel for determining the at least one parameter. In the part, a channel structure is formed, having an input region for the entry of a partial flow of the medium and having a measuring channel branching off from the input region. The input region has a separation zone with a separation opening, and at least two projections which protrude from mutually opposite interior walls of the input region into the input region.

Abstract: A measurement structure that projects into an intake passage is provided with a shunt plate adjacent to a first passage that extends from an air inlet to an air outlet. A second passage is formed around the shunt plate so as to bypass the first passage. An air flow rate measuring element is disposed in the second passage. An edge of the shunt plate is located on a imaginary line or distant from the imaginary line to the second passage side, in which the imaginary line is parallel to the axis of the intake passage and passing through the top of the air inlet, whereby dust or liquid matter is prevented from entering the second passage. Alternatively, the shunt plate is provided with an inclined portion which is projected to the first passage so that the inclined portion is inclined toward the air outlet. As a further alternative, the shunt plate is provided with an inclined portion that is inclined toward the air inlet and has a through-hole.

Abstract: A device for determining at least one parameter of a medium flowing in a line, in particular the intake air mass of an internal combustion engine, has a part provided for introducing into the line, having at least one measuring channel for conducting at least one subflow of the medium flowing in the line, and having at least one measuring element situated in the measuring channel for determining the at least one parameter, in which the part may be introduced into the line with a predetermined orientation with respect to the medium flowing in the line in the main flow direction.

Abstract: A device for determining a parameter of a medium flowing in a line, according to the related art, does not offer sufficient protection for a measuring element from liquid or solid particles which may dirty or damage the measuring element in an unwanted way. A device has an input region, whence, on the one hand, the flowing medium flows into the measuring channel, and on the other hand, through at least one separation opening, liquid and solid particles flow, and thus flow so as to bypass the measuring channel.

Abstract: A laminated filter is fit in a passage space formed in a body. The laminated filter is made of a mesh plate including a mesh part, a first blocking plate including a blocking part, a second blocking plate including a blocking part, and a third blocking plate including a blocking part which are arbitrarily combined and layered. Accordingly, a three-layered mesh part is placed between a main passage and a sensor passage and a blocking wall is constructed of the three blocking parts.

Abstract: A method of measuring absolute static pressure in a microfluidic device transporting a working fluid that is immiscible in a first selected gas environment, includes providing a first fluid conducting channel having an atmosphere provided by the first selected gas environment in a sealed environment and in communication with the microfluidic device at a first point of communication; providing a first sensing mechanism that is electrically interrogated, disposed adjacent to the first fluid conducting channel; and transporting the working fluid under pressure conducted by the microfluidic device into the first fluid conducting channel such that the volume transported into such first fluid conducting channel varies depending upon the absolute static pressure of the working fluid.

Abstract: A flow meter and electrically operable valve assembly having integral flow meters provide detection of very low water flows, along with ease of installation and compact packaging for a water supply control system. The flow detection is particularly useful for systems that control household water supplies to prevent flooding, but is also useful in other applications such as agricultural and industrial systems where low water flow rates must be determined. All of the controls and features are integrable within a compact package that occupies essentially the same volume and piping space as a conventional electrically operable valve.

Abstract: A device for measuring the mass of a flowing medium with a temperature-dependent measurement element has a measurement conduit whose faces, which extend perpendicular to a surface fixed by the measurement element, are inclined and approach each other in the flow direction of the medium in the measurement conduit. The invention is provided for measuring the mass of a flowing medium to measure the intake air mass of internal combustion engines.

Abstract: A thermal mass flow controller includes a sensor assembly, a valve assembly, and mass flow controller housing. A thermal ground limits the conductive thermal path between the mass flow controller housing and the sensor assembly and, due to the limited cross-section of the thermal ground, substantially eliminates externally imposed thermal gradients within the sensor assembly. The controller also includes a thermally dissipative element that conducts thermal energy along a path from the valve assembly away from the sensor assembly.

Abstract: A device for measuring the flow of a fluid has a primary duct and a bypass arranged in series to the primary duct. The bypass has a first section and a second section. A baffle plate with a hole for the passage of the fluid is arranged in the first section. The second section comprises two parallel secondary ducts. In the first section, a turbulent flow dominates, while the flow in the second section is primarily laminar. If the turbulent effects in the bypass are sufficiently strong, the ratio of the flows in the primary duct and the bypass can be substantially independent of the fluid properties and of the flow rate. By using two parallel secondary ducts in the second section, high flow rates and therefore strongly turbulent effects can be achieved without exceeding the measuring range of the sensor.

Abstract: A flow controller is provided for delivering a precise volume of fluid such as high purity fluid streams to a processing destination, such as a wafer processing chamber. The flow controller includes a base with a seamless slot formed in a face thereof, providing a predictable pressure drop. The seamless slot is in fluidic communication with a sensor channel extending downwardly from the seamless slot first having temperature sensors thereon for inferring the mass flow through the flow controller. A valve is in fluidic communication with the seamless slot and is operably connected to the temperature sensors such that the valve opening is adjusted until the mass flow inferred by the temperature sensors is equal to a desired mass flow.

Abstract: Methods and systems for preventing degradation of a sensor exposed to a harsh fluid, such as one that might corrode or be exposed to radioactive contaminants, live pathogens, freezing temperatures, overheating, particle deposition or condensable vapors is disclosed. An auxiliary purge stream of comparatively clean fluid or purge fluid is utilized, which flows past the sensor in opposition to the harsh fluid, thereby preventing the harsh fluid from contacting and degrading the sensor. The clean fluid itself may comprise a purge gas, such as clean, dry air, or a liquid that is compatible with the composition of the harsh fluid. The flow and pressure of the clean fluid can be adjusted utilizing one or more supply regulator valves.

Abstract: In a gas-flow measuring instrument for measuring a gas flow in an intake gas passage for sucking gas, an abnormal output, deterioration per hour, stain, and breakage of a flow measuring element caused by fluid and foreign materials contained in intake gas are reduced. A gas-flow measuring instrument disposed in an intake gas passage for sucking gas for measuring a gas flow includes a bypass passage for bringing gas flowing along the intake gas passage, a bypass passage inlet opened to the upstream side of a main stream direction of gas in the intake gas passage, and a flow measuring element disposed in the bypass passage.

Abstract: A thermal mass flow controller includes a sensor assembly and mass flow controller housing. A thermal ground limits the conductive thermal path between the mass flow controller housing and the sensor assembly and, due to the limited cross-section of the thermal ground, substantially eliminates externally imposed thermal gradients within the sensor assembly.

Abstract: A thermal mass flow controller includes a sensor assembly, a valve assembly, and a mass flow controller housing. A thermally conductive element conducts heat from the valve assembly away from the sensor assembly, thereby reducing uncontrolled contributions of heat to the sensor assembly.

Abstract: A flow meter and electrically operable valve assembly having an integral flow meter provide detection of very low water flows along with ease of installation and compact packaging for a water supply control system. The flow is particularly useful for systems that control household water supplies to prevent flooding, but is also useful in other applications such as agricultural and industrial systems where low water flow rates must be determined. All of the controls and features are integrable within a compact package that occupies essentially the same volume and piping space as a conventional electrically operable valve.

Abstract: A device for determining a parameter of a medium flowing in a line, according to the related art, does not offer sufficient protection for a measuring element from liquid or solid particles which may dirty or damage the measuring element in an unwanted way.

Abstract: An ALC circuit is turned on (S1), a nozzle is shifted to a sampling position (S2), and after the ALC circuit has been turned off (S3), the nozzle is allowed to start discharging air from its tip (S4). While the nozzle is being lowered, the inner pressure of the nozzle is monitored (S5, S6), and upon detection of an increase in the pressure, the discharging process of air and the nozzle lowering process are stopped (S7), while the monitoring of the magnitude of the pressure is continued (S8). When the magnitude of the pressure is being maintained within a permissible range of the change for a predetermined time, it is judged that the tip of the nozzle has come into contact with the true liquid level, and after a suction operation of a sample (S9), the nozzle is raised (S10).

Abstract: The invention relates to a fluid meter comprising an outside wall of determined thickness to which a flange connected to a pipe is fixed via fixing members which penetrate into holes organized respectively in the thickness of said flange and in said outside wall in order to install said meter on said pipe, said meter having an opening for fluid feed which is organized in the outside wall and behind which there is provided a “feed” chamber into which the fluid coming from the feed opening flows, wherein the fluid meter also has studs disposed inside the feed chamber so as to modify the fluid flow, and in which internal perforations are provided in alignment with the holes for receiving portions of said fixing members.

Abstract: A split-flow-type flowmeter in which an end portion of a flow splitter tube 1 is inserted into a main-flow pipe 10 having a diameter D. A flow splitter tube 1 includes a U-shaped split-flow passage 1a. A detection element is disposed at a bottom portion (not shown) of the U-shaped split-flow passage 1a. The split-flow passage 1a assumes a flow path structure symmetrical with respect to a plane passing through the detection element. A flow inlet 2a and a flow outlet 2b of the split-flow passage 1a face in mutually opposite directions along the flow direction of the main-flow pipe 10 and open symmetrically at the same position on the flow cross section of the main-flow pipe 10.

Abstract: A method of measuring absolute static pressure at one or more positions along the wall of a microfluidic device transporting a working fluid that is immiscible in a first selected gas environment, includes providing a first fluid conducting channel having an atmosphere provided by the selected gas environment under a sealed environment and in communication with the microfluidic device at a first point of communication; providing a visual scale adjacent to the first fluid conducting channel; and transporting the working fluid under pressure conducted by the microfluidic device into the first fluid conducting channel such that the volume transported into such first fluid conducting channel varies depending upon the absolute static pressure of the working fluid at the first point of communication, whereby the absolute static pressure at the first point of communication is visually determined depending on the position of the interface of the working fluid and the first selected gas environment in the first fluid

Abstract: A flow rate and flow velocity measurement device. A part of a flow 10 in a main flow pipe 1, which is a detection object, is introduced into a passage of a divided flow pipe 2 and becomes a flow 11. The divided flow pipe 2 has a curved portion 2c or rather an inverted arc portion in which the flow is abruptly changed in direction or rather inverted by protuberances 2a, 2b formed preferably in symmetry in upstream and downstream sides of the curved portion 2c. Outside the main flow pipe 1, there is disposed on the bottom portion of the curved portion 2c of the divided flow pipe 2 a detection element 5 fixed to a support body 4 while protruding preferably 0.05-0.3 mm from flow passage faces 2e, 2f in the vicinity thereof. An opposed face 2d opposite to the detection element 5 protrudes toward the detection face so as to throttle the passage and to accelerate a flow speed at the element.

Abstract: Devices for measuring the mass of a flowing medium using a temperature-sensitive measuring element have the disadvantage that considerable measuring errors may occur in the event of a pulsating flow characterized by flow fluctuations. In order to counteract these measuring errors, the device (1) possesses an axially extending measuring duct (33), in which a temperature-sensitive measuring element (20) is accommodated. The measuring duct (33) extends from the inlet mouth (36) to a deflecting duct (34), out of which the flowing medium flows out from an outlet orifice (46) without any axial distance from the inlet mouth (36) and radially underneath the latter. The invention is provided for measuring the mass of a flowing medium, in particular for measuring the intake air mass of internal combustion engines.

Abstract: A split-flow-type flowmeter in which an end portion of a flow splitter tube 1 is inserted into a main-flow pipe 10 having a diameter D. A flow splitter tube 1 includes a U-shaped split-flow passage 1a. A detection element is disposed at a bottom portion (not shown) of the U-shaped split-flow passage 1a. The split-flow passage 1a assumes a flow path structure symmetrical with respect to a plane passing through the detection element. A flow inlet 2a and a flow outlet 2b of the split-flow passage 1a face in mutually opposite directions along the flow direction of the main-flow pipe 10 and open symmetrically at the same position on the flow cross section of the main-flow pipe 10.

Abstract: The present invention provides an air flow measuring device comprising a housing with a sub-passage having a inlet and a outlet for air flow formed in the housing, the sub-passage further having a predefined curvature with a maximum downstream point and a flow measuring element located in the sub-passage at a position at least further downstream from the point.

Abstract: An apparatus to normalize a flow rate of a fluid in a main flow channel is provided. The apparatus uses a moveable member, such as a flexible membrane disposed for reciprocating displacement, to produce a constant dither flow of the fluid that is independent of fluid composition. This dither flow generates a signal output from a normalizing flow sensor that both represents a characteristic property of the fluid and a flow rate calibration factor. A similar apparatus to determine the characteristic property or flow rate calibration factor is also provided. The devices disclosed may be used in numerous industrial, process, and medical flow system applications for normalization of flow sensors and to derive other properties of a fluid.

Abstract: A flow proportioning assembly for dividing a portion of a fluid flow such as gas for presentation to a sensor includes a holder member having a central opening and forming an exterior peripheral passageway when inserted within a conduit of a flow meter housing. A resistor member can be adjustably mounted in the central opening downstream of a holder member aperture to encourage a laminar flow pattern and a large entrance port and a large exit port can communicate with a passageway that is operatively connected with a sensor. The exit port is downstream of the resistor member. Flexible fastener members can engage the resistor member and the holder member for ease of mounting. The resistor member can also comprise a helical arrangement of small fluid passageways to encourage laminar flow.

Abstract: A flow rate sensor comprises: a main fluid passage for a fluid to flow therealong; a detecting pipe conduit coaxially disposed in the main fluid passage; a temperature sensing element for sensing the temperature of the fluid; a flow rate sensing element including a flow rate detecting resistance made of a thermo-sensitive electrically resistant material, the flow rate detecting element being disposed in the main fluid passage in a manner such that the flow rate detecting resistance is exposed to the fluid flowing therethrough; and a control circuit for controlling an electric current flowing to the flow rate detecting resistance such that the temperature of the flow rate detecting resistance may be maintained at a predetermined value which is higher to some extent than a fluid temperature detected by the temperature sensing element. The main fluid passage involves a converged section whose passage cross sectional area becomes gradually smaller towards the downstream side thereof.

Abstract: A thermal type air flow amount measuring apparatus is provided for measuring, a amount of air flowing in an air flow passage. The apparatus includes a bypass passage unit for bypassing a part of the air flowing through the air flow passage into the bypass passage. A flow amount measuring device is disposed in the bypass passage unit. A throttle unit is disposed upstream of the flow amount measuring device in the bypass passage unit and a support unit is disposed downstream over the throttle unit to support the flow amount measuring unit.