Abstract: An apparatus for obtaining information on the content and flow rate in a fluid flow, e.g. a mixture of oil and water flowing in, for example, a pipe, including means for conveying a flowing fluid, means for generating a differential pressure in said fluid, and means for measuring said differential pressure. Means for measuring a capacitance are provided including at least one electrode, and the differential pressure generating means is arranged substantially at the same position along the pipe as the electrode of the capacitance measuring means. Thereby the differential pressure generating means effectively defines an earth electrode for said capacitance measuring means. Means are provided for combining a result from said differential pressure measuring means with a result from said capacitance measuring means to thereby obtain information on the content and flow rate in a fluid flow.

Abstract: A method and apparatus for measuring the flow rate of bitumen froth through a pipeline is provided. A flow meter device is provided including a conduit comprising an approach section having a diameter less than the diameter of the pipeline and a venturi section having in series a converging section, a throat section and, optionally, a diverging section, the converging section of the venturi section being disposed relative to the approach section, and a means for measuring the pressure difference ?P between two points that are separate from one another in the flow direction, one point being on the approach section and the other point being on the throat section. In one embodiment, a heating means for heating the conduit is provided.

Abstract: A flow meter for measuring the volume of fluid flowing through the meter includes an inner cylindrical tube through which the fluid flows and an outer cylindrical tube tending over the inner cylindrical tube. The outer cylindrical tube is radially spaced from the cylindrical inner tube to provide an annular cylindrical space between the inner cylindrical tube and the outer cylindrical tube. A seal between the inner cylindrical tube and the outer cylindrical tube closes the annular cylindrical space adjacent ends of the annular cylindrical space. The inner cylindrical tube further defines at least one opening in a wall of the inner cylindrical tube to balance the fluid pressure in the annular cylindrical space with the pressure in the inner cylindrical tube.

Abstract: Methods and apparatus determine phase fractions for phases within a fluid mixture flow under a wide range of flow conditions including wet-gas flow. Appropriate flow algorithms can utilize this phase fraction information with a total flow rate of the mixture to find individual flow rates for phases, such as oil, water, and gas or gas and liquid, which can represent a combination of oil and water phases. For some embodiments, a multiphase flowmeter includes an array of spatially distributed pressure sensors configured to determine a velocity of the mixture flow and hence the total flow rate, which is applied with information from a differential pressure meter to calculate the bulk density of the fluid mixture. Further, additional speed of sound information or a water-in-liquid ratio as may be determined by spectral analysis can enable differentiation between the oil and water phases.

Abstract: A flow meter tube is provided having improved performance in the measurement of the flow rate of erosive material. The internal wall surface of the flow meter tube has a smooth erosion-resistant coating thereon to protect the flow meter wall from erosion by the erosive fluid flowing there through. The coating has a Rockwell C hardness of 56 to 70 and a surface roughness of less than or equal to 250 microinches rms.

Abstract: A method and apparatus for measuring the flow rate of a fluid within tubing disposed within a downhole wellbore. The present invention provides an inverse Venturi meter inserted within tubing with an enlarged inner diameter portion. Pressure differential is measured between the enlarged inner diameter portion and another portion of the inverse Venturi meter. Flow rate is determined from the pressure differential and the density of the fluid.

Abstract: A method and apparatus is disclosed for identifying changes in composition in a flow containing an oil/hydrocarbon gas fluid mixture, including a measurement of the respective holdups of any two of the gas, oil and water; and measurements to determine attenuation or scattering of high energy photons passing through the mixture; and combining holdup measurements and attenuation or scattering measurements to detect the presence or concentration of a hetero-component in the mixture.

Abstract: A venturi type of primary flow element comprising a tubular body defining a flow path having open ends and walls and including in series, a converging section, a cylindrical throat section, and a diverging section, where the bottom walls of each of said sections are in alignment and present a smooth unangled surface to flowing fluid therein.

Abstract: The present invention is directed to a flow meter that obtains the individual flow rates of gas, liquid hydrocarbons, and water in a predominantly gas-containing flowing fluid mixture. The flow meter comprises a water content meter (7) that provides a signal representing a measure of the water content of said fluid. The flow meter also comprises a double differential pressure generating (3) and measuring (4) structure, denoted a DDP-unit (2), that provides two measurement signals (6A and 6B) representing two independent values of differential pressure (DP) in said fluid (1). In addition to the above, the meter also comprises a signal processing unit (8) having inputs (9A-C) for receiving the measurement signals and the water content signal, and a calculation module (10) which calculates values representing the volumetric flow rates of said gas, liquid hydrocarbons and water in said fluid.

Abstract: A flowmeter is provided that comprises a leadframe assembly (140) and a body (144) disposed at least partially around the leadframe assembly (140). The body (144) has a flow passage therethrough that comprises a first channel (178) having a first port (166), a second channel (180) having a second port (168), and a flow altering element (182) disposed within the second channel (180). First and second pressure sensors (174 and 176) are disposed within the body (144) and coupled to the leadframe assembly (140) for measuring a first pressure within the first channel (178) and a second pressure within the second channel (180), respectively. An integrated circuit (155), which is coupled to the leadframe assembly (140), to the first pressure sensor (174), and to the second pressure sensor (176), is configured to determine the rate of flow through the flow passage from the first pressure and the second pressure.

Abstract: A method and apparatus are provided for determining the gas flow rate of a gas-liquid mixture which has a gas volume fraction (GVF) of at least 85% and which is conveyed along a conduit. The conduit is fitted with a differential pressure flow meter and a fluid densitometer. The method comprises: measuring the pressure difference across the differential pressure flow meter and measuring the density of the mixture using the densitometer; estimating the GVF of the mixture from the measured density; and calculating the gas flow rate from the measured pressure difference and measured density. A corrective term which comprises the estimated GVF is used in the calculation to correct the gas flow rate for the high GVF value of the mixture.

Abstract: A method and apparatus for fluid flow straightening and measurement introduces a high beta nozzle or venturi in-line with existing conduit. A fluid velocity measuring device is positioned in the throat of the high beta nozzle and measurements of velocity at multiple points in a plane perpendicular to the direction of fluid flow are taken. The velocity data points are then averaged and produce an output signal from which fluid flow rate can be determined.

Abstract: A method, system, controller and computer program product, for controlling the flow of a multiphase fluid comprising gas and liquid in a conduit, which conduit is provided at a downstream side with a flow restriction and a valve having a variable aperture, which method comprises the steps of selecting a flow parameter of the multiphase fluid in the conduit as a function of a pressure difference over the flow restriction; selecting a setpoint for the flow parameter; allowing the multiphase fluid to flow at a selected setpoint of the aperture of the variable valve; determining the pressure difference over the flow restriction and determining an actual value of the flow parameter from the pressure difference, without using a measurement of another variable in order to determine an actual gas/liquid ratio pertaining to the pressure difference at the flow restriction; controlling the flow of the multiphase fluid by determining a deviation of the flow parameter from its setpoint, determining an updated setpoint

Abstract: A flow meter comprising a tubular main-body and a cover plate formed by printed circuit board which carries two pressure sensing devices tightly packed by soft rubber material for sensing the pressure head of and the pressure difference between the inlet and outlet of the flow meter. Since the cover plate is mounted on, and fastened to the main-body by fastening screw, but not by adhesive to form a complete unit, the cover plate can therefore bear high fluid pressure without crack or damage, i.e., shall increase the capacity of bearing pressure, the service life and accuracy, and decrease the occurrence of malfunction to the flow meter.

Abstract: A system and method provides a flow measurement system for steady-state and transient flow. A housing contains a sleeve such that the sleeve is isolated from external mechanical loads. A flow measurement element, such as a venture or nozzle, is located in the sleeve. Strains along the sleeve caused by flow pressure changes through the flow element are detected and related to fluid flow rate.

Abstract: A method and apparatus for measuring the flow rate of a fluid within tubing disposed within a downhole wellbore. The present invention provides an inverse Venturi meter inserted within tubing with an enlarged inner diameter portion. Pressure differential is measured between the enlarged inner diameter portion and another portion of the inverse Venturi meter. Flow rate is determined from the pressure differential and the density of the fluid.

Abstract: A well has a downhole flow meter that is installed in a sub in a string of tubing. The flow meter has a body having an external profile that lands on a landing profile in the sub. The body has a passage with a throat area of reduced diameter. Upstream and downstream body ports in a side wall of the body are in fluid communication with the throat area and a downstream portion of the passage downstream of the throat area. Seals are located between the body and the sub, defining an upstream annular chamber and a downstream annular chamber surrounding the body, the chambers being in communication with the upstream and downstream body ports. Upstream and downstream sub ports in a side wall of the sub are in fluid communication with the upstream and downstream chambers. A sensor circuit is in operative engagement with the sub ports for determining a flow rate based on a pressure difference sensed between the throat area and the downstream portion of the passage in the body.

Abstract: A connecting duct for providing a fluid pathway between an outlet of a low pressure compressor and an inlet of a high pressure compressor is provided. The connecting duct includes a main body that defines a fluid pathway adapted to direct a flow of fluid between a main body inlet and a main body outlet. The main body also includes a diffusing section that decreases a velocity of the flow of fluid. A flow de-swirling section is disposed between the diffusing section and the outlet of the main body. The flow de-swirling section straightens the flow of fluid.

Abstract: A respiratory tract differential-pressure flow sensor, including a tube having a distal end that is insertable into a respiratory tract, an interfering body disposed within the tube proximal to the distal end and having a first edge facing one end of the tube and a second edge facing away from the end, the interfering body extending across the diameter of the tube, a first pressure sensing port operative to sense an air pressure, the first port being disposed in the first edge not abutting the wall of the tube, and a second pressure sensing port operative to sense an air pressure, the second port being disposed in the second edge not abutting the wall of the tube, where either of the edges is inclined inwardly towards the axis of the interfering body extending across the diameter of the tube.

Abstract: A flow meter arrangement has a venturi-type flow meter having a tubular flow channel for conveying a gas flow to be measured and in which there is provided a constriction. The arrangement further has a hot wire flow meter having a sensing element located within the flow channel and a measurement system that receives an output from the venturi-type flow meter and an output from the hot wire flow meter, and that determines a gas flow rate therefrom.

Abstract: A flow direction detector is provided which includes a flow disruptor positioned in a fluid flow path to effect a detectable differential flow characteristic to such flow path based on fluid flow direction, and a sensor arrangement configured to detect such detectable differential flow characteristic within the flow path.

Abstract: An airway adaptor that includes a tubular body having a first gas flow passage defined therein. A protrusion extends from an interior wall of the tubular body into the gas flow passage. The protrusion includes a distal end portion spaced apart from the interior wall of the tubular body, and a second gas flow passage defined through the protrusion. An inlet to the second gas flow passage is provided at the distal end portion of the protrusion, and an outlet of the second gas flow passage is provided at an exterior portion of the tubular body. A pair of sidewalls are disposed on the distal end portion of the protrusion. Each sidewall is generally parallel to a direction of a flow of gas through the first passage. The inlet of the second gas flow passage is disposed between the pair of sidewalls.

Abstract: Apparatus for measuring the composition and flow rate of a fluid (1) comprising a mixture of e.g. oil and water in a pipe (2), wherein an integrated mechanical structure (3) serves as a microwave resonator sensor for providing permittivity measurements and where the mechanical structure also functions as a differential pressure element for providing flow rate measurements.

Abstract: A method and apparatus for measuring the flow rate of a fluid within tubing disposed within a downhole wellbore. The present invention provides an inverse Venturi meter inserted within tubing with an enlarged inner diameter portion. Pressure differential is measured between the enlarged inner diameter portion and another portion of the inverse Venturi meter. Flow rate is determined from the pressure differential and the density of the fluid.

Abstract: A meter for the measurement of the gas mass flow rate and total liquid mass flow rate of a two phase or multiphase fluid is disclosed. The meter comprises a series of three flow element, the firs element is arranged to mix fluids passing therethrough and the second and third elements are each arranged to provide a measurement of the differential pressure across that element. The second and third elements may be added to an existing installation with an element capable of performing mixing, after the mixing element. The second and third elements provide independent measurements by having different configurations presented to the fluids passing therethrough. The first and third elements may comprise conduits with internal projections and the second element may be a venturi. A flow element for use in such a meter is also disclosed.

Abstract: A flow rate sensor includes a first body and a second body airtightly and detachably abutting each other. The first body and the second body respectively-include a passage defined therein. The two passages are tapered relative to each other. The first body and the second body respectively have a path defined therein. The two paths respectively communicate with a corresponding one of the two passages in the first and second bodies. A sensing device is airtightly sandwiched between the first and second body and corresponds to the two paths for calculating the different of the fluid that flows through the two passages in the first and second bodies.

Abstract: A method and device for obtaining an accurate flow rate measurement through a fluid flow system. A nozzle and gauge tapping combination is connected to a fluid flow system. Fluid enters the nozzle as turbulent flow. As the fluid passes through the nozzle, the turbulent flow is converted to laminar flow due to the shape of the nozzle. Once in laminar flow, the pressure at that point in the nozzle is constant, and therefore the pressure, and thus flow rate, can be measured with greater accuracy.

Abstract: A flow direction detector is provided which includes a flow disruptor positioned in a fluid flow path to effect a detectable differential flow characteristic to such flow path based on fluid flow direction, and a sensor arrangement configured to detect such detectable differential flow characteristic within the flow path.

Abstract: A method and an apparatus for measuring the concentrations of the components of a fluid are described, which can be used to measure the concentrations of the components continuously in real time and to monitor a high pressure gas, and is suitably used for in-line monitoring. In the method and the apparatus, a fluid sample is conducted through a measuring tube, wherein the measuring tube has a small aperture with a constant diameter in a fluid flow path. The pressure difference (P1?P2) between the upstream and the downstream of the small aperture and the flow rate at the downstream of the small aperture are measured to determine the concentrations of the components of the fluid.

Abstract: Apparatus for measuring the composition and flow rate of a fluid (1) comprising a mixture of e.g. oil and water in a pipe (2), wherein an integrated mechanical structure (3) serves as a microwave resonator sensor for providing permittivity measurements and where the mechanical structure also functions as a differential pressure element for providing flow rate measurements.

Abstract: A differential-pressure flow sensor for airflow measurement in the presence of water condensation, for use with mechanical ventilators. The pressure-sensing ports at either end of the interfering body are displaced from the inner surface of the surrounding tubing, so as to prevent obstruction of the pressure-sensing ports by free flowing condensed water. The leading edge of the interfering body is angulated so as to deflect airflow towards the pressure-sensing port on the trailing edge of the interfering body, thereby flushing water droplets away from the port. The sides of the interfering body are sloped so as to generate turbulent boundary layer airflow at areas distant from the pressure-sensing ports, thereby encouraging water condensation away from the ports.

Abstract: A method and apparatus is disclosed for determining the flow rates of fluid phases in a pipe containing multiple fluid phases. A Venturi is provided to measure total volumetric flow rate measurement and a holdup measurement is taken approximately 3-10 pipe diameters downstream of the Venturi. The holdup measurement is made at a downstream location where a substantial amount of mixing occurs and the differences between the velocities of the fluid phases can effectively be ignored. The flow rates of the phases can thus be determined directly from the holdup measurements.

Abstract: A method and apparatus for fluid flow straightening and measurement introduces a high beta nozzle or venturi in-line with existing conduit. A fluid velocity measuring device is positioned in the throat of the high beta nozzle and measurements of velocity at multiple points in a plane perpendicular to the direction of fluid flow are taken. The velocity data points are then averaged and produce an output signal from which fluid flow rate can be determined.

Abstract: Improvement in a mass air flow meter having an elongated hollow body having a venturi member therein, the improvement comprising channels formed in the outside surface of the venturi member, lands defined by such outside surface which bear against the inside surface of the hollow body, such lands, together with the inside surface of the hollow body, directing the flow of sample air to be measured through such channels, around the outside surface of the venturi member and axially thereof, a first one of the channels being annular and in communication with the interior of the meter for receiving sample air therein, a second one of the channels serving as a measurement path in which the mass of sample air is measured as it travels therethrough, and a third one of the channels being annular and in which air exiting from the measurement path is accumulated before being recombined with the main flow of air traveling through the meter.

Abstract: A venturi-assisted flow meter arrangement is disclosed. The venturi is positioned in a pipe or conduit containing the fluid mixture to be measured upstream of the flow meter. The flow meter is preferably a flow rate meter and/or a phase fraction meter. When the fluid mixture is passed through the venturi, it is homogenized or mixed, which can increase the accuracy of the measurements made by the downstream flow meter. Additionally, the venturi can be used to compute the flow momentum of the fluid mixture, which may be used to calibrate or double check the operation of the flow meter, or allow it to compute the phase fraction for a three phase mixture.

Abstract: A flow sensing venturi system includes a venturi body and a manifold mounted thereto. The manifold is thermally isolated from the venturi body. A multiple of sensor ports are formed into the manifold which support each individual sensor and provide communication between the sensor and one or more passageways. The passageways communicate with a single high-pressure and a single low-pressure sense line. The high and low pressure sense line tap respective high and low pressure areas within the venturi body. The sensor is individually screwed into the manifold to provide an airtight connection for two independent sensor input ports. Replacement of individual sensors is thereby greatly simplified.

Abstract: According to one embodiment of the invention, a computerized method for determining a flow rate of a fluid flowing through a conduit having an obstruction flow meter includes receiving a &bgr; ratio value indicative of a &bgr; ratio of the obstruction flow meter, receiving a pressure differential value indicative of a pressure differential across the obstruction flow meter, receiving a density value indicative of a density of the fluid, receiving a discharge coefficient formula for the obstruction flow meter, the discharge coefficient formula being a function of the &bgr; ratio of the obstruction flow meter and an Euler number for the fluid flowing through the conduit, and determining, by the computer, the flow rate based on the received &bgr; ratio value, the received pressure differential value, the received density value, and the received discharge coefficient formula. The determined flow rate may either be the volumetric flow rate or the mass flow rate.

Abstract: A venturi-assisted flow meter arrangement is disclosed. The venturi is positioned in a pipe or conduit containing the fluid mixture to be measured upstream of the flow meter. The flow meter is preferably a flow rate meter and/or a phase fraction meter. When the fluid mixture is passed through the venturi, it is homogenized or mixed, which can increase the accuracy of the measurements made by the downstream flow meter. Additionally, the venturi can be used to compute the flow momentum of the fluid mixture, which may be used to calibrate or double check the operation of the flow meter, or allow it to compute the phase fraction for a three phase mixture.

Abstract: A method of determining a rate of flow of a first gas in a pipe includes placing a flow-restricting device in the pipe such that the device and/or the pipe define a first channel section and a second channel section. The second channel section is disposed downstream from the first channel section. The first channel section has a first cross-sectional area. The second channel section having a second cross-sectional area less than the first cross-sectional area. A source of a second gas is provided in fluid communication with the second channel section. A low pressure in the second channel section is caused by an increased flow velocity and creates a flow of the second gas into the second channel section. A rate of a flow of the second gas into said second channel section is measured. A mathematical relationship between the rate of the flow of the second gas into the second channel section and the rate of flow of the first gas in the pipe is ascertained.

Abstract: An air is fed from an air supply source to a detecting nozzle via a first fixed throttle section. The air is jetted from the detecting nozzle to the workpiece W to obtain a nozzle back pressure for detecting a position of a workpiece W. A first diffuser section is disposed downstream of the first fixed throttle section.

Abstract: Oil field management systems and methods for managing operation of one or more wells producing a high void fraction multiphase flow. The system includes a differential pressure flow meter which samples pressure readings at various points of interest throughout the system and uses pressure differentials derived from the pressure readings to determine gas and liquid phase mass flow rates of the high void fraction multiphase flow. One or both of the gas and liquid phase mass flow rates are then compared with predetermined criteria. In the event such mass flow rates satisfy the predetermined criteria, a well control system implements a correlating adjustment action respecting the multiphase flow. In this way, various parameters regarding the high void fraction multiphase flow are used as control inputs to the well control system and thus facilitate management of well operations.

Abstract: A pressure signal from a differential pressure transducer is dynamically compensated for error, such as zero point drift, due to time passage or temperature change. A processor associated with a pressure transducer employs an algorithm to continuously monitor the pressure signal to determine when signal characteristics indicate zero signal level. Then the algorithm determines a current correction factor or updates a previously determined correction factor, and records the current correction factor in a non-volatile memory as a function of ambient temperature. When the signal characteristics indicate other than a zero signal level, such as when differential pressure is non-zero, the algorithm recalls from memory and applies the most recently determined correction factor for a corresponding ambient temperature. Suitable time intervals for determining a current correction factor are found by monitoring the process signal and seeking those time periods when the signal is both calm and quiet, i.e.

Abstract: A method of measuring a gas mass fraction (X) in a mass of liquid and gas flowing in direction (A) along pipeline (2) which includes a venturi formed by throat (10), convergent portion (12) and divergent portion (14). Adjacent the venturi (12, 10, 14) but upstream is a flow conditioner (28) creating a uniform mixture of gas and liquid downstream so as to reduce or avoid slip between the gas and liquid phases in the venturi. Differential pressure (DP1) is measured between a position upstream of the flow conditioner and a position intermediate the flow conditioner and venturi. Differential pressure (DP2) is measured between the throat and a position intermediate the flow conditioner and venturi. Differential pressure (DP3) is measured across the venturi. Computer (50) calculates the gas mass fraction (X) using a formula that may take the form: X=a·(DP1)b·(DP2)c·(DP3)d·(DP2−DP3)e·(DP1+DP3)f, in which a, b, c, d, e and f are constants.

Abstract: A flow sensing venturi system includes a venturi body and a manifold mounted thereto. The manifold is thermally isolated from the venturi body. A multiple of sensor ports are formed into the manifold which support each individual sensor and provide communication between the sensor and one or more passageways. The passageways communicate with a single high-pressure and a single low-pressure sense line. The high and low pressure sense line tap respective high and low pressure areas within the venturi body. The sensor is individually screwed into the manifold to provide an airtight connection for two independent sensor input ports. Replacement of individual sensors is thereby greatly simplified.

Abstract: A restricted area measurement device, method, and system for measuring a multi-phase mixture are disclosed. The device may include two current electrodes within a restricted area, at least two voltage electrodes within the restricted area, and at least one meter, wherein a multi-phase enthalpy of the multi-phase mixture may be determined by the at least one meter in accordance with a resistivity. The system includes a restricted area, two current electrodes within the restricted area, at least two voltage electrodes within the restricted area, and at least one measuring device, wherein a multi-phase enthalpy of the multi-phase mixture is determined by the at least one measuring device in accordance with a resistivity. The method includes exciting a first electrical current between two current electrodes within the restricted area, measuring a voltage between at least two voltage electrodes within the restricted area, and measuring a multi-phase enthalpy of the multi-phase mixture according to a resistivity.

Abstract: A flow meter for use in an oil well has a central bore region in which an annular tube is fixed co-axially with the central bore region by a ring, which also seals the gap between the inner bore of the central bore region and the tube at its downstream end, thus forming a pocket open to the direction of fluid flow through the central bore region. The pocket brings the fluid to rest, thereby converting all of the dynamic pressure of the fluid into static pressure. This has the effect of maximizing the pressure differential obtainable between the central bore region and a position upstream of the tube, which allows an electronic calculation to be made to provide a more accurate flow rate measurement than would have been possible without the pocket.

Abstract: A restricted area measurement device, method, and system for measuring a multi-phase mixture are disclosed. The device may include two current electrodes within a restricted area, at least two voltage electrodes within the restricted area, and at least one meter, wherein a multi-phase enthalpy of the multi-phase mixture may be determined by the at least one meter in accordance with a resistivity. The system includes a restricted area, two current electrodes within the restricted area, at least two voltage electrodes within the restricted area, and at least one measuring device, wherein a multi-phase enthalpy of the multi-phase mixture is determined by the at least one measuring device in accordance with a resistivity. The method includes exciting a first electrical current between two current electrodes within the restricted area, measuring a voltage between at least two voltage electrodes within the restricted area, and measuring a multi-phase enthalpy of the multi-phase mixture according to a resistivity.

Abstract: Multiphase flow calculation software and computer-readable media carrying computer executable instructions for calculating liquid and gas phase mass flow rates of high void fraction multiphase flows. The multiphase flow calculation software employs various given, or experimentally determined, parameters in conjunction with a plurality of pressure differentials of a multiphase flow, preferably supplied by a differential pressure flowmeter or the like, to determine liquid and gas phase mass flow rates of the high void fraction multiphase flows. Embodiments of the multiphase flow calculation software are suitable for use in a variety of applications, including real-time management and control of an object system.

Abstract: An apparatus for sampling the emission content of an exhaust gas from an exhaust source has an exhaust inlet adapted for connecting the exhaust source with a venturi metering device for measuring the flow rate of the exhaust gas. The venturi metering device includes a housing having an entrance section, a throat section, and an exit section, the throat section having a smaller diameter than the entrance and exit sections. The housing includes first and second pressure transducers that produce an electrical output that characterizes the pressure that the pressure sensing means senses, the electrical outlet enabling a computer of the venturi metering device to accurately measure the pulsating flow of the exhaust gas in both directions.

Abstract: A method and apparatus for preventing flow rate errors derived from an ultrasonic flow meter utilized in semiconductor fabrication operations. The ultrasonic flow meter is generally configured to include an extension chamber connected to a thin branch tube of the ultrasonic flow meter. A venturi tube can be positioned at an outflow location of the ultrasonic flow meter, such that the thin branch tube is broached into the venturi tube, wherein bubbles contained in a slurry flow are forced directly into the outflow location to thereby prevent inaccurate flow measurements derived from the ultrasonic flow meter. The extension chamber may be configured to reduce an inflow velocity associated with the slurry slow and ensure that the bubbles with not drift with the slurry flow. Additionally, a diameter of the branch tube may be configured such that the diameter is much smaller than a diameter associated with an inflow and/or outflow tube of the ultrasonic flow meter.