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.

Abstract: An air flow meter disposed in an intake pipe has a bypass member having a U-shaped bypass passage, into which part of air flowing through the intake pipe is introduced. An outflow port disposed at a downstream air side of the bypass passage is surrounded at its three sides by opposing surfaces of a pair of side walls and a wall surface of a partition wall disposed at “an upstream air side of the outflow port”. Further, the outflow port is opened in an air flow direction in the bypass passage and in an air flow direction in the air flow passage. Therefore, air flowing through the bypass passage is partially discharged into the air flow passage through the outflow port gradually before joining main air flow in the air flow passage, thereby restricting decrease in air flow velocity and occurrence of turbulence in the bypass passage.

Abstract: A thermal type air flow measuring instrument is mounted to a main passage forming an intake air passage of an internal combustion engine and is provided. with an auxiliary passage which includes a heating resistor and a temperature sensing resistor therein and an electronic circuit which is electrically connected to the heating resistor and the temperature sensing resistor. The auxiliary passage is a passage including at least one bent portion composed of a first path substantially parallel to the main passage and a second path having a path different in flow direction from the first path. A member forming the auxiliary passage is fixed in a united form to only a case member for interiorly protecting the electronic circuit, and the case member is fixed to the outer wall surface of the intake air passage.

Abstract: A device for measuring the mass of a flowing medium, with a temperature-dependent measurement element that substantially reduces measurement errors due to a pulsating flow that is characterized by means of flow fluctuations. The device has a measurement conduit which extends from an inlet to an outlet that is adjoined by a first section piece of a deflection conduit. The medium flows from the outlet to the first section piece and is deflected by an edge face into a second section piece of the deflection conduit. The edge face of the first section piece of the deflection conduit is embodied as inclined in relation to the flow direction in the measurement conduit. The invention is provided for measuring the mass of a flowing medium, for the intake air mass of internal combustion engines.

Abstract: A laminar flow element for use in thermal mass flow sensors and flow controllers is designed to provide a high degree of precision. The precision laminar flow element includes a laminar flow element having a generally pointed entry end for maintaining a pure laminar flow path around the laminar flow element. The generally pointed entry end serves to direct an incoming gas flow stream equally about an outer surface of the laminar flow element. In this way, the laminar flow path is uniform so as to maintain a desired flow accuracy. The laminar flow element provides a plurality of standoff pins protruding from the outer surface of the laminar flow element to maintain a substantially equal radial clearance around the outer surface. By maintaining a substantially equal radial clearance from one laminar flow element to another, the laminar flow element is highly interchangeable.

Abstract: A device for measuring the mass of a flowing medium which avoids measuring liquid components entrained in the medium. The device includes an interrupting body, which is accommodated upstream of the device, in a section of an air intake line that tapers in the flow direction, in order to filter out liquid components entrained in the flow by means of the interrupting body and to divert the liquid components from the measuring device. 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 thermal mass flow controller having a thermal mass flow meter with an orthogonal thermal mass flow sensor includes a base defining a primary fluid flow path therein for carrying a flow of fluid to be metered. A pressure dropping bypass is positioned in the primary fluid flow path. A flow measuring portion of a thermal mass flow sensor is oriented substantially transversely or orthogonally with respect to and is in communication with the primary fluid flow path. The flow measuring portion includes a portion of an electrical bridge for determining a temperature of the sensor and produces a mass flow rate signal in response thereto. A valve is connected to an outlet of the primary flow path to control the flow of fluid in response to the mass flow rate signal.

Abstract: Plate-like straightening members are provided between a main conduit and a metering pipe stored in the main conduit to suppress the deviation of a flow of a fluid in the main conduit and stabilize a flow in the metering pipe.

Abstract: Measuring device for measuring the flow rate of a gas flow or liquid flow by means of a rotary piston device consisting of two rotary pistons which are placed in a pipe section and are mounted in such a way that they rotate about a rotary shaft, which rotary pistons are placed relative to each other and relative to the pipe section in such a way that by interaction with each other they shut off the pipe section. During the rotation the two rotary pistons always remain in contact with the wall of the pipe section at one side and with each other at the other side, a quantity of gas or liquid being allowed through every turn. The measuring device is characterized in that it consists of a number of parallel branches, with a rotary piston device accommodated in each branch, the rotary piston devices being synchronized with each other by means of synchronization means in such a way that the flow rate is approximately constant.

Abstract: A flow rate meter having a temperature-dependent measuring element in which the device has a measuring conduit, which is equipped with a flow connection that extends from an inlet to an outlet, in order to cause some of the medium flowing in the measuring conduit, in the flow connection, to bypass the measuring element. The device is intended for measuring the mass of a flowing medium, in particular for measuring the aspirated air mass of internal combustion engines.

Abstract: An apparatus for measuring gas flow rate is comprised of a pipe body whose inside space performs as a passage for flowing measured gas. A housing including a generally U-shaped bypass passage is integrally formed with the pipe body. A plate-type flow-rate detection element is disposed in a first passage of the bypass passage, and a passage restricting portion is disposed in a second passage of the bypass passage downstream of the first passage. The inlet portion of the bypass passage is disposed in the vicinity of an axial center of the pipe body, and the outlet port of the bypass passage is disposed in the vicinity of a pipe wall of the pipe body. Therefore, the influence of a pulsating flow to the flow-rate detection element is decreased, and the high-accuracy detecting of gas flow-rate is executed.

Abstract: A thermal type air flow measuring instrument is mounted to a main passage forming an intake air passage of an internal combustion engine and is provided with an auxiliary passage which includes a heating resistor and a temperature sensing resistor therein and an electronic circuit which is electrically connected to the heating resistor and the temperature sensing resistor. The auxiliary passage is a passage including at least one bent portion composed of a first path substantially parallel to the main passage and a second path having a path different in flow direction from the first path. A member forming the auxiliary passage is fixed in a united form to only a case member for interiorly protecting the electronic circuit, and the case member is fixed to the outer wall surface of the intake air passage.

Abstract: Detection of the flow of a fluid, and also measurement of the flow of a fluid, is provided by feeding the fluid flow through a cylindrical chamber to form a cyclonic circulation of the fluid in the chamber. A movable member is moved by the fluid flow. As one example a ball rotates around the inside of the chamber and the passage of the ball detected, at a particular position. An alternative is an annular member also rotated. There can be an optical detection or electronic detection. Output signal can be generated by the movement. Such signals can be processed to give flow rates. The chamber is positioned in a by-pass flow line, with the flow rate of the by-pass related to the total flow.

Abstract: A bypass flowmeter for measuring the material flow in a conduit. An optimum pressure drop is developed across the flowmeter by coupling the material outlet of the flowmeter to the throat of a venturi positioned within the conduit. This increased pressure drop improves the material flow rate through the flowmeter. This enhances flowmeter accuracy and sensitivity and the flowmeter's ability to measure mass flow rates for low density materials such as gas. The ratio of the material flow within the flowmeter to that of the conduit is derived with improved precision over prior arrangements which assume a constant ratio of material flow between the flowmeter and the conduit. The material flow information for the conduit is obtained for materials having a varying viscosity by the use of a differential pressure sensor which measures the pressure drop across the flowmeter and transmits this information to instrumentation which uses it to derive material flow information for the conduit with improved precision.

Abstract: A multi-channel mass flow transducer has a single laminar flow element in a primary fluid flow path and multiple secondary flow paths in parallel with and in fluid communication with the primary flow path. Flow restriction elements are disposed in one or more of the secondary flow paths to establish different flow rate measurement "channels" having particular flow rate ranges. The multi-channel transducer of the present invention is capable of measuring fluid flow rates over an extended range and eliminates the need for multiple transducers to measure varying fluid flows.

Abstract: An airflow amount measuring body is formed such that two pipes are arranged in parallel and a bypass passage having an inverted U-shape is provided. The passage sectional areas A1, A2 and A3 of an upstream side passage, a turning section and a downstream passage of the bypass passage are set as A1<A2 and A1<A3, more preferably A2/A1.gtoreq.1.14 and A3/A1.gtoreq.1.20 to suppress contraction flow. A venturi tube section is provided at the lower end of the flow amount measuring body at the peripheral wall of the venturi tube section at the downstream side. A passage enlarging section is provided at the part of the peripheral walls of the venturi tube section at the downstream side where the bypass flow joins, and a guide section for guiding the bypass flow is provided at an outflow port of the bypass passage.

Abstract: A flow meter is adapted to measure the flow rate of a fluid flowing in the interior of a sensing conduit. The flow meter includes one sensor element disposed along the flow path of the fluid externally of the sensing conduit closer to one fluid flow port of the conduit, another sensor element disposed along the flow path of the fluid externally of the sensing conduit closer to the other fluid flow port of the conduit, an elongated structure disposed along the flow path of the fluid internally of the sensing conduit and away from the two sensor elements for reducing the fluid flow space in the sensing conduit, apparatus for heating the sensor elements, and apparatus for detecting a temperature differential between the sensor elements. The elongated structure has an end that engages the sensing conduit at a fluid flow port. The elongated structure may be a wire that is pre-bent or straight prior to its insertion into the sensing conduit, or may be a tube.

Abstract: A laminar flow element for use in flow metering devices has a laminar flow element plug with an upstream end and a downstream end and a linear extent between the upstream end and the downstream end, the laminar flow element plug configured to be positioned within a base cavity with the upstream end oriented toward the direction of flow, and sensor taps through walls of the base cavity positioned inboard of the laminar flow element plug so that entrance effect is eliminated, error due to flow cross-sectional area differential is eliminated, and orifice effect is minimized, to produce a laminar flow with linear pressure drop across the sensor taps as a function of flow rate. Coaxial laminar flow guides are fixed coaxially about at least a portion of the length of the laminar flow element plug to increase the number of flow passages to enable linear measurements of higher flow rates.

Abstract: A Karman vortex flow meter has detection passages located along a fluid flow in a duct. Flow outlets of the detection passages are disposed on an end face of a vortex generation element and flow inlets are disposed upstream from the flow outlets. Heating coils for detecting flow velocity change of a fluid caused by a negative pressure of a Karman vortex are mounted in the detection passages. A flow meter is used that lessens dust accumulation on heating coils, etc., and reliably detects Karman vortexes.

Abstract: A laminar flow device includes a plurality of disks and a plurality of spacers alternately stacked together. The plurality of disks are defined by first disks and second disks, each of the first disks having a hole formed through a central portion thereof, and each of the second disks having a plurality of holes formed through an outer peripheral portion thereof. The first disks and the second disks are alternately arranged with the spacer interposed between any two adjacent ones of the disks.

Abstract: A mass fluid flow controller has a valve which is controlled by a controller rod which is substantially pivotally mounted on a metallic diaphragm which stretches and unstretches with the movement of the rod. The actuation of the rod movement is by the expansion and contraction of an actuator wire which is heated for the expansion and allowed to cool for the contraction. The primary fluid flow path through the controller is straight. A sensor conduit, providing a parallel sensor fluid flow path, is connected in position using metallic sealer members which extend into openings to the primary fluid flow path and which are rounded along the direction through such openings. The pressure drop, along the primary fluid flow path, to create flow through the sensor conduit, is provided by a fluid flow restrictor having a core and having lengths of wire along the core which are squeezed between the core and a tapered fluid flow path wall in the vicinity of the sensor conduit input and output connections.

Abstract: An improvement on locomotive bubble-type fuel level measuring systems tests or monitors the integrity of the bubble-type pneumatic system by observing the rate of bubble formation, in addition to gauging fuel level. A bubble-type fuel level detection system bubbles a volume of air through a bubble tube. As air exits from the bottom of the tube, bubbles form in the fuel. These bubbles cause small variations in back-pressure in the tube as each bubble grows in size and eventually breaks free from the opening in the tube. The frequency these variations is proportional to the airflow or bubble rate at the bottom of the bubble tube such that pneumatic leaks or other problems can be detected by declaring a problem condition if the bubble rate falls below a predetermined threshold.

Abstract: An air flow rate measuring device for measuring intake air flow rate in an automotive engine, improved to reduce any error attributable to variation in the configurations of air cleaner and/or duct forming air passage upstream of the flow rate measuring device, thus offering high accuracy of the flow rate measurement. In one aspect of the invention, the inlet opening of a sub-air passage is disposed to contain the axis of a main air passage, while the outlet opening of the sub-air passage is disposed in the vicinity of a wall defining the main air passage. In order to cause a local reduction of the pressure of the principal of the air flow at the outlet opening, a protrusion or a flat surface which causes impediment to the flow if air in the main air passage is provided immediately upstream of the outlet opening.

Abstract: A Karman vortex flow meter has a detection passages located along a fluid flow in a duct 1. Flow outlets of the detection passage are disposed on an end face of a vortex generation element and flow inlets 3 are disposed upstream from the flow outlets. Heating coils for detecting flow velocity change of a fluid caused by a negative pressure of a Karman vortex are mounted in the detection passage, and swell portions are formed upstream from the heating coils in the detection passage. The flow meter that can prevent water drops, bubbles, etc., from adhering to heating coils, etc., and detect Karman vortexes stably.

Abstract: A flow meter for measuring a flow rate of fluid includes a body providing a main passage through which the fluid flows. A plurality of support elements connect an inner wall surface of the body and a central element so as to support the central element substantially at the center of the main passage. An introducing port opens to the central element for introducing a part of the fluid flowing through the main passage. A branch passage is formed within the central element, through which such part of the fluid flows. A sensor is disposed within the branch passage for measuring a flow rate within the branch passage. An outlet opens to a portion of the central element located at upperstream of the downstream ends of the support elements for returning the fluid flowing through the branch passages to the main passage.

Abstract: A flow meter for measuring a flow rate of fluid includes a body providing a main passage through which the fluid flows. A plurality of support elements connect an inner wall surface of the body and a central element so as to support the central element substantially at the center of the main passage. An introducing port opens to the central element for introducing a part of the fluid flowing through the main passage. A branch passage is formed within the central element, through which such part of the fluid flows. A sensor is disposed within the branch passage for measuring a flow rate within the branch passage. An outlet opens to a portion of the central element located at upperstream of the downstream ends of the support elements for returning the fluid flowing through the branch passages to the main passage.

Abstract: A flowmeter with a main conduit having a constriction formed therein through which a main flow passes, and a by-pass conduit which is in fluid connection with the main conduit upstream and downstream of the constriction and in which a by-pass flow passes in response to a pressure drop across the constriction. The constriction includes a conical body which is movable within the main conduit to produce an increasing flow area in response to an increasing pressure drop across the constriction. A by-pass flowmeter is provided in the by-pass conduit which produces signals in proportion to a by-pass flow through the by-pass conduit. A calibrated electronic signal converter converts signals produced by the by-pass flowmeter to signals which correspond to the total flow through the main conduit.

Abstract: A housing structure for mass air flow sensors includes an auxiliary passage way, internal to the structure, that diverts a portion of the main air flow towards sensing elements. The sensing elements are shielded from the main air flow, so the contaminants separate from the diverted air at the point of diversion and continue downstream in the main air flow. The decontaminated, diverted air passes over the sensing elements and out of the housing structure through two exit openings located in the rear of the structure. The housing structure, by locating the sensing elements within itself, away from the main air flow, and locating exit openings for the diverted air behind a blocking wall, is also able to eliminate the effect of backflow air over the mass air flow sensing elements.

Abstract: A hot wire type airflow meter of the present invention comprises a housing defining a main passage through which air passes, a central member supported in the main passage of the housing and having an inlet portion for taking in a part of air flowing through the main passage, a bypass passage communicating with the inlet portion, and an outlet portion for returning air passing through the bypass passage to the main passage, and sensing means disposed in the bypass massage for measuring the airflow rate in the bypass passage, wherein the bypass passage comprises an upstream side meander portion which has a meandering passage at an upstream side of the sensing means, a straight tube portion formed as a straight tube and accommodating the sensing means, and a downstream side passage communicating the straight tube portion with the outlet portion.

Abstract: An air flow rate measuring device for measuring intake air flow rate in an automotive engine, improved to reduce any error attributable to variation in the configurations of air cleaner and/or duct forming air passage upstream of the flow rate measuring device, thus offering high accuracy of the flow rate measurement. In one aspect of the invention, the inlet opening of a sub-air passage is disposed to contain the axis of a main air passage, while the outlet opening of the sub-air passage is disposed in the vicinity of a wall defining the main air passage. In order to cause a local reduction of the pressure of the principal of the air flow at the outlet opening, a protrusion or a flat surface which causes impediment to the flow if air in the main air passage is provided immediately upstream of the outlet opening.

Abstract: A method for measuring a pressure drop at a component within a flue gas desulfurization vessel caused by a gas flow includes locating a plurality of taps near the component to be measured in order to receive a portion of the flow. A line leading from the tap is connected to a pressure measuring device in order to measure the pressure at the component based on the flow fed into the tap. After the pressure is measured, the line is disconnected from the pressure device and connected to a cleaning device in order to clean the connecting line and tap. After cleaning the tap, air is blown through the line in order to dry the line for the next measurement. The pressure drop determined is used to calculate the liquid flow passing through the system from pre established relationships.

Abstract: A system for measuring the flow rate of gas includes a flow head having a sensor thermoresistor mounted transversely to the flow of gas, and a reference thermoresistor mounted parallel to the flow of gas, both thermoresistors having equal resistance versus temperature functions. Each thermoresistor is connected in a feedback control circuit, in which each thermoresistor is separately supplied with current to heat it, the current first passing through a fixed resistance in series with each of the thermoresistors. The current supplies are servo controlled to equalize the resistance of each thermoresistor with that of its associated fixed resistance. The power consumed by each thermoresistor at its equilibrium resistance is measured to provide a power indicative signal associated with each thermoresistor. The two power indicative signals are compared to generate a delta power signal. An empirically-derived flow rate-versus-delta power curve is stored as a look-up table in a computer memory.

Abstract: A method and apparatus for determining the total flow rate of air flowing through a ventilation installation with a free suction fan (15) is described. The flow rate or a corresponding pressure is determined by measurement of the partial flow rate or a corresponding pressure at at least one measurement point in the vicinity of the inlet opening of the fan. A measurement tube (20) open at both ends is suitably used, and oriented with its longitudinal axis in the inflow direction, flow sensors being arranged inside the measurement tube. In this way, there is obtained good measurement accuracy within a large flow range.

Abstract: A package burner has a fan rotatably driven at constant speed. Air from the surrounding atmosphere is induced by the fan through an open end of a conduit which guides the air to the fan from which the air is propelled down an outlet passage to mix as combustion air in a chamber with fuel gas from a gas supply nozzle so that flames issue from the chamber. A valve in the conduit or outlet passage can be set to regulate how much air is supplied as combustion air. A fluidic oscillator has an inlet open to the atmosphere and has an outlet open to the interior of the conduit. The observed frequency of the fluidic oscillator is a function of the flow rate of air through the fluidic oscillator and is also a function of the flow rate of air along the conduit. Therefore the measured frequency of the fluidic oscillator can be used to calculate the amount of combustion air being supplied along the conduit in unit time.

Abstract: The present invention relates to an incidence probe, in particular for an aircraft, comprising at least two pressure inlets. To this end, it comprises a least one flowmeter (1) and a pneumatic restriction (4) arranged in series between two pressure inlets.

Abstract: A Karman vortex flow meter in which a main passage 1 and a bypass passage 2 are adjacent to each other; a throttle portion 12 is formed at the inlet of the bypass passage to continuously reduce the cross-sectional surface area of the passage, and a flared portion 14 is formed in the bypass passage 2 so that the cross-sectional surface area of the passage is continuously enlarged from an intermediate portion of the passage to the outlet of it. Further, the inlets and the outlets of the main passage and the bypass passage are each arranged in single planes perpendicular to the flow direction of the fluid to be measured, and the boundary portions 16, 17 between the main passage and the bypass passage 2 are respectively formed to have a smallest thickness.

Abstract: Device for measuring pressure differences or mass portions in a fluid flow--gas or liquid--and/or for implementing processes for mixing fluids, whereby when in use the fluid flows into the device, then passes a part therein where the fluid flow is laminar and the flow measurement is made, and finally flows out of the device, whereby the device has a turbulence filter which is integrated therein, with a settling chamber behind it. The fluid then first flows through that filter, so that a laminar flow leads to the flow measuring element.

Abstract: A mass flowmeter has a flow tube inserted within the confines of a conduit containing a material flow. Mass flow information is derived for the material flow within the conduit by generating mass flow information for the material flowing within the smaller flow tube positioned within the conduit and then by adjusting the calculations for the flow tube to represent mass flow information for the conduit. In accordance with a first embodiment of the invention, a pressurized cover is positioned around the flow tube to isolate the exterior surface of the flow tube from the material in the conduit. The space between the exterior of the flow tube and the cover is pressurized to a pressure equal to that of the material in the conduit. Both sides of the flow tube walls are at the same pressure so that a flow tube comprised of thinner and more flexible material may be used.

Abstract: Elbow mass flow meter. The present invention includes a combination of an elbow pressure drop generator and a shunt-type mass flow sensor for providing an output which gives the mass flow rate of a gas that is nearly independent of the density of the gas. For air, the output is also approximately independent of humidity.

Abstract: An apparatus and method are disclosed for accurately and economically measuring fluid flow within a closed conduit system. The apparatus includes a means for extracting a proportional amount of the fluid flow, a flowmeter reduced in size from the main conduit system for measuring the flow of the extracted proportional amount of fluid, and a means for returning the extracted portion of fluid to the fluid flow. The fluid flow is extracted and returned without disrupting the fluid flow. A means for promoting the extraction of the proportional amount of fluid flow is provided within said conduit between the means for extracting and returning the fluid flow.

Abstract: A device and method for creating favorable conditions for achieving adjustable laminar fluid flow is described. In the practical example of a thermal mass flow meter the laminar flow element contains a porous, open celled, flexible material such as stainless steel mesh. The mesh creates a labyrinthine flow path, for the creation of laminar fluid flow, within the laminar flow element. Means for compressing or elongating the steel mesh renders the laminar flow element adjustable over an extended fluid flow range, and provides optimal fluid dynamics.

Abstract: A split path mass flowmeter includes a housing having a longitudinally extending bore within which a flow splitter is positioned. The flow splitter includes a tapered portion having a taper corresponding generally to that of a tapered portion of the bore. The tapered portion of the flow splitter is nested within the tapered portion of the bore, the tapered portions of these elements thereby forming a self-holding retention section for non-adjustably retaining the flow splitter within the bore. The retention section may taper outwardly or inwardly in the direction of fluid flow. A calibration section may precede or follow the retention section or may be combined into the retention section. Further, a recovery section may be separately disposed downstream of the retention and calibration sections or may be combined along with the calibration function in the retention section.

Abstract: A hydrodynamic fluid divider is provided whereby by a shunt line directs a portion of the overall flow of a defined fluid stream through a flow measuring device, such as a Coriolis mass flow meter. The proportion of the shunt line flow portion is determined by the relationship of various fluid restrictions within the shunt line and the main line of the divider. The measured flow value for the shunt line flow is utilized along with a scale-up factor to determine the overall flow through the divider. The proportional relationship of the shunt line to the overall flow permits a reduction in the size and operational requirements for the flow measuring device.

Abstract: A bypass unit of a flowmeter sensor includes a chamber, inlet and outlet paths through which a fluid flows into and out of the chamber, an upstream bypass path through which a portion of the fluid is diverted from the chamber to a sensor tube, and a downstream bypass path through which the portion of the fluid is returned from the sensor tube to the chamber. A bypass member is arranged within the chamber and a space is defined between the peripheral wall of the housing and the bypass member. The bypass member includes inlet and outlet ports formed in coaxial relation to the inlet and outlet paths, respectively, and a plurality of radial ports. A substantially cylindrical partition is disposed between the peripheral wall of the housing and the bypass member to define a space between the peripheral wall of the housing and the partition and between the partition and the bypass member.

Abstract: A disconnectable flow connector is formed of (a) a frusto-conical taper pin having a longitudinal bore through which the end portion of a flow tube of a mass flow sensor is inserted and secured and (b) a connector base containing a matched frusto-conical taper bore. The taper pin can be press-fit into the taper bore to form a fluid flow passage having a leakage level less than about 10.sup.-9 scc/sec helium.

Abstract: A disconnectable flow connector is formed of (a) a frusto-conical taper pin having a longitudinal bore through which the end portion of a flow tube of a mass flow sensor is inserted and secured and (b) a connector base containing a matched frusto-conical taper bore. The taper pin can be press-fit into the taper bore to form a fluid flow passage having a leakage level less than about 10.sup.-9 scc/sec helium. with a series of spaced apart, transverse grooves separated by lands in sealing engagement with the matched taper bore.

Abstract: A vortex flowmeter wherein a main body and a fitting plate with a by-pass are integrally formed with each other and the fitting plate placed an an outlet of a passage of small diameter and of a constant section extending from an inlet of a large diameter with a continuous contraction. The passage in the main body includes a vortex generator and a vortex sensing means for detecting a vortex produced by the vortex's generator. The by-pass line is composed of a plurality of round through-holes arranged in a circular portion of the fitting plate.

Abstract: A volumetric fluid flowmeter and method utilizes a venturi nozzle in the flow being measured, along with a negative feedback fluidic oscillator driven by a small bypass flow diverted from the main flow upstream of the venturi nozzle, and subsequently re-introduced into the main flow in the throat section of the venturi.

Abstract: A flow dividing structure for a mass flow controller includes a base having a main passage which includes an upsream circular passage, a downstream circular passage, and a tapering circular passage which connects the upstream and downstream circular passages. A plug inserted in the main passage includes a first cylindrical portion, a second cylindrical portion and a tapering frustoconical portion. A first annular passage is defined between the first cylindrical portion and the inner circumferential surface of the upstream circular passage. A second annular passage is defined between the second cylindrical portion and the inner circumferential surface of the downstream circular passage. A tapering annular passage is defined between the tapering frustoconical portion and the inner circumferential surface of the tapering circular passage. A flow measuring passage bypasses the tapering circular passage and connects the upstream circular passage with the downstream circular passage.

Abstract: A flowmeter has an elongated housing with a fluid inlet, a fluid outlet and an axial passage therebetween. The fluid passage contains a flow splitter section and is connected to a flow sensor assembly. The flow splitter section is formed by a surface defining a longitudinal fluid path and a flow splitter secured in the fluid path, so as to form an annular gap between the surface of the fluid path and the flow splitter. The surface of the fluid path defines a tapered calibration bore. The flow splitter has a tapered calibration section comprising the upstream portion of the flow splitter and at least one tapered expansion section comprising the downstream portion of the flow splitter. The taper of the calibration section is substantially parallel to the taper of the calibration bore, and the taper of the expansion section diverges away from the taper of the calibration bore.