Abstract: A liquid aspiration method which includes a method for determining the quality of the aspirated sample through mathematical analysis of the standard deviation of the residuals of the linear regression analysis of the aspiration pressure profile generated between the onset of actual aspiration and the end of actual aspiration and comparison of the results with predetermined known values.

Abstract: The present invention relates to a method and relevant electronic device (10) for determining the hydraulic flow rate in a pump driven by a synchronous electric motor (12), said motor (12) being of the type comprising a rotor (14), equipped with a permanent magnet, which is rotation-driven by the electromagnetic field generated by a stator (16) equipped with pole pieces (18) with relevant windings. The method comprises an indirect measuring of the flow rate through the following steps of: acquiring at least one pump operation variable; comparing the value of said variable with a predetermined correlation table to hydraulic flow rate values and determining a corresponding flow rate value.

Abstract: A fluid flow rate and density measuring apparatus is disclosed including a section of cylindrical conduit comprising a measurement section or housing for the flow sensor. The flow sensor housing is fixedly attached to a conduit at its distal ends allowing fluid to pass through the open ends of the sensor housing as fluid flows through the conduit. An elongated, streamlined, cylindrically symmetric structure is located within the housing with its longitudinal axis aligned along that of the housing thereby forcing fluid through the annular gap between the exterior of the elongated cylindrical structure and the interior wall of the sensor housing.

Abstract: A wireless water flow monitoring and leak detection system and method are provided. The system includes a base station, a memory, and a central processing unit configured to control the operation of the system and to analyze stored data. A plurality of highly-sensitive wireless flow sensor nodes are each installed individually on a supply line of a water fixture in a facility having a plurality of water fixtures. The wireless flow sensor nodes can periodically read and store a data point corresponding to either a flow condition or a no flow condition occurring at the water fixture. A plurality of coordinator nodes are configured to wirelessly relay data between the plurality of wireless flow sensor nodes and the base station. The base station is configured to determine based on an analysis of the stream of data points whether a leak exists in any of the water fixtures, and if a leak is determined to exist, a maintenance alert is generated.

Abstract: The method and system includes a flow sensor including two hot wire gas flow sensing elements connected to identical, but independent electronic circuitry, positioned in parallel, transverse to gas flow direction, and separated by a post that serves to shadow the downstream element. The flow sensors are dynamically compensated during respiratory therapy by use of digital to analog conversion, which provides for more accurate identification of flow direction and more accurate gas flow in volume measurements. The method and system incorporates the flow sensors in the y-piece of a breathing circuit.

Abstract: A method for performing system characterization in situ for a system comprising a actuator controlled by a proportional controller. The system includes a quasi-linear region characterized by a slope of the system response and by a delay in the quasi-linear region of the system. The system includes at least one dead zone (DZ).

Abstract: A method is performed in an electronic system having (i) hardware configured to perform electronic operations and (ii) an air filter configured to remove contamination from an air stream that cools the hardware. The method, which identifies when to change an air filter, involves obtaining, from a set of particle sensors, a set of sensor signals in response to sensed particles in the air stream. The method further involves generating particle count data and processing the data based on the set of sensor signals, and providing an output signal having one of a first value and a second value based on the particle count data. The output signal indicates that the air filter should be changed when the output signal has the first value. The output signal indicates that the air filter should not be changed when the output signal has the second value.

Abstract: A system for dispensing cryogenic liquid to a use device includes a bulk storage tank providing LNG to a sump containing a meter submerged in LNG. A temperature probe is also submerged in the LNG. A dispensing line is positioned between the meter and dispensing hose and includes a dispensing valve. A drain line bypasses the dispensing valve and features a check valve so that LNG trapped in the hose after dispensing is returned to the sump due to pressurization by ambient heat. A capacitance probe is submerged in the LNG in the sump and provides a dielectric that is compared by a microprocessor with the dielectric for pure methane at the same temperature to determine the purity of the LNG. An approximate linear relation between density and dielectric may be used to determine density and mass flow for the LNG from the measured dielectric.

Abstract: A system is described for controlling the flow of a sample fluid through a substrate having first and second surfaces and at least one area with a plurality of through-going capillary channels. The system comprises a housing having a chamber for receiving the substrate and a pressure differential generator capable of generating and maintaining a pressure difference over the substrate.

Abstract: A method and system for determining the effect of precipitation on flow within a sewer network includes identifying a modeled response of the sewer to a precipitation event. Once the modeled response is identified, scaled responses to future precipitation events may be predicted, in real time, by measuring intervals of the precipitation event and calculating the scaled response as a function of the modeled response and the precipitation quantity measured during the precipitation event.

Abstract: A system for dispensing cryogenic liquid to a use device includes a bulk storage tank providing LNG to a sump containing a meter submerged in LNG. A temperature probe is also submerged in the LNG. A dispensing line is positioned between the meter and dispensing hose and includes a dispensing valve. A drain line bypasses the dispensing valve and features a check valve so that LNG trapped in the hose after dispensing is returned to the sump due to pressurization by ambient heat. A capacitance probe is submerged in the LNG in the sump and provides a dielectric that is compared by a microprocessor with the dielectric for pure methane at the same temperature to determine the purity of the LNG. An approximate linear relation between density and dielectric may be used to determine density and mass flow for the LNG from the measured dielectric.

Abstract: A mass flowmeter system for use in steam reformation of hydrocarbons includes a Coriolis flowmeter in a hydrocarbon feedstock line. The feedstock carbon content is estimated by close approximation, which facilitates selective control operations governing the relative amounts of steam and hydrocarbon materials as they feed a hydrogen processing unit. The relative amounts of steam and hydrocarbon feedstock are adjusted on the basis of real time measurements.

Abstract: A system for dispensing cryogenic liquid to a use device includes a bulk storage tank providing LNG to a sump containing a meter submerged in LNG. A temperature probe is also submerged in the LNG. A dispensing line is positioned between the meter and dispensing hose and includes a dispensing valve. A drain line bypasses the dispensing valve and features a check valve so that LNG trapped in the hose after dispensing is returned to the sump due to pressurization by ambient heat. A capacitance probe is submerged in the LNG in the sump and provides a dielectric that is compared by a microprocessor with the dielectric for pure methane at the same temperature to determine the purity of the LNG. An approximate linear relation between density and dielectric may be used to determine density and mass flow for the LNG from the measured dielectric.

Abstract: A method and apparatus for in-situ calibration of quantity measurement of a fluid flowing in a channel, in which a device for measuring the volume of the fluid is disconnected from the fluid flow, measuring fluid is accumulated in a pre-determined amount on site of the calibration, this pre-determined amount of measuring fluid is led through the measuring device with a pre-determined volume flow, in the course of which the volume values measured by the measuring device are saved, then the measured volume values and the real values of the fluid led through are compared to each other and, with this, the quantity measurement of the flowing fluid is calibrated.

Abstract: A method and system for determining the effect of precipitation on flow within a sewer network includes identifying a modeled response of the sewer to a precipitation event. Once the modeled response is identified, scaled responses to future precipitation events may be predicted, in real time, by measuring intervals of the precipitation event and calculating the scaled response as a function of the modeled response and the precipitation quantity measured during the precipitation event.

Abstract: A flowmeter capable of real-time fuel mass flow measurement involving extremely low fuel mass flow quanta. The flowmeter includes a dual flow path conduit system, a flow control for alternating the selection of one flow path exclusive of the other flow path, an indicator tube interfaced with the conduit system, an indicator shuttle slidably mounted in the indicator tube, and a sensor for sensing the position of the indicator shuttle relative thereto.

Abstract: The invention relates to a flow divider and a process for dividing a fluid flow into a number of fluid flows, in particular in analytical and/or preparative fluid measurement technology and/or in micro-fluid systems. The flow divider exhibits at least one working sensor, which is assigned to one of the fluid flows and which comprises a control unit for regulating the pressure of one of the fluid flows and/or for regulating one of the fluid flows. The control unit is coupled to the at least one working sensor and to an actuator for changing the fluid flow. At least a number of working sensors corresponding to the number of divided fluid flows is provided, whereby respectively at least one of the working sensors is assigned to one of the fluid flows and whereby the working sensors enable recording of the respective fluid flow. According to the process of the present invention the control unit regulates the fluid flows such that the ratio between at least two of the fluid flows remains substantially constant.

Abstract: An apparatus comprising: a base plate and a cover plate, said plates spaced apart by a pair of transfer blocks being mounted and held between the base plate and the cover plate, mounted between the transfer blocks is one or more fluid flow sensor switches, for measuring the presence of liquid flowing there through. The invention can serve as a substantially automatic means of assuring that there is always fluid available for an applicator, such as a wet blade, as the fluid flow sensors are demand driven. If the fluid runs low, the back pressure on the output side of the fluid line drops, and delta pressure across the fluid sensor increases, causing the fluid sensor to open and fluid to flow. An electrical switch, such as a reed switch, signals the controller that fluid is flowing.

Abstract: A flow meter strut assembly includes a strut portion having a first end plate, a second end plate, a longitudinally adjustable flow meter support structure between the first and second end plates, and curved mounting surfaces formed on outer surfaces of each of the first and second end plates of the strut portion. At least one flow meter is adjustably mounted on the flow meter support structure. The flow meter support structure is adjustable longitudinally by a turnbuckle assembly connected between the flow meter support structure and the second end plate.

Abstract: A system for dispensing cryogenic liquid to a use device includes a bulk storage tank providing liquid natural gas (LNG) to a sump containing a meter submerged in LNG. A temperature probe is also submerged in the LNG. A dispensing line is positioned between the meter and dispensing hose and includes a dispensing valve. A drain line bypasses the dispensing valve and features a check valve so that LNG trapped in the hose after dispensing is returned to the sump due to pressurization by ambient heat. A capacitance probe is submerged in the LNG in the sump and provides a dielectric that is compared by a microprocessor with the dielectric for pure methane at the same temperature to determine the purity of the LNG. An approximate linear relation between density and dielectric may be used to determine density and mass flow for the LNG from the measured dielectric.

Abstract: A mass flowmeter system for use in steam reformation of hydrocarbons includes a Coriolis flowmeter in a hydrocarbon feedstock line. The feedstock carbon content is estimated by close approximation, which facilitates selective control operations governing the relative amounts of steam and hydrocarbon materials as they feed a hydrogen processing unit. The relative amounts of steam and hydrocarbon feedstock are adjusted on the basis of real time measurements.

Abstract: A method and system for determining the effect of precipitation on flow within a sewer network includes identifying a modeled response of the sewer to a precipitation event. Once the modeled response is identified, scaled responses to future precipitation events may be predicted, in real time, by measuring intervals of the precipitation event and calculating the scaled response as a function of the modeled response and the precipitation quantity measured during the precipitation event.

Abstract: The invention relates to a flow divider (20) and a process for dividing a fluid flow (30) into a number of fluid flows (31, 32), in particular in analytical and/or preparative fluid measurement technology and/or in micro-fluid systems. The flow divider (20) exhibits at least one working sensor (41, 42), which is assigned to one of the fluid flows (31, 32) and which comprises a control unit (55) for regulating the pressure of one of the fluid flows (31, 32) and/or for regulating one of the fluid flows (31, 32), which is coupled to the or each working sensor (41, 42) and an actuator (51) for changing this fluid flow (31). At least a number of working sensors (41, 42) corresponding to the number of divided fluid flows (31, 32) is provided, whereby respectively at least one of the working sensors (41, 42) is assigned to one of the fluid flows (31, 32) and whereby the working sensors (41, 42) enable recording of the respective fluid flow (31, 32).

Abstract: A method for computing three dimensional unsteady flows about an object. An allowable error is established for the vorticity term calculations, and object geometry is provided giving surface points on an object and a region of interest. A mesh is established incorporating points on the object. Initial flow conditions are set at the surface. Vorticity values that will satisfy boundary conditions are set at the provided surface points. A new mesh is established incorporating the provided points and other points in the region of interest. Boxes are generated containing the provided points and other points. Velocities and pressures at each point are calculated from the flow conditions, vorticity values and boundary conditions., A time variable is incremented and each point is moved by applying the calculated velocity. Vorticity at each point is then recalculated. The method is iterated starting with the step of satisfying boundary conditions until the incremented time variable exceeds a predetermined value.

Abstract: A sensor element and a method for determining the concentration of at least one gas component, especially of a nitrogen oxide, in a gas, mixture. For this purpose, the sensor element includes at least one first electrode exposed to the gas component to be analyzed and at least one reference electrode), which are electrically interconnected by a first solid electrolyte. Furthermore, an electric current between the first electrode and a further electrode is measured continuously or in sampling fashion in response to the application, especially the setting, of an electric voltage between first electrode and the reference electrode due to a chemical reaction proceeding at the first electrode, by which the concentration of the gas component to be analyzed in the gas mixture can be determined. During this process, the application or setting of the electric voltage takes place only during recurring time intervals.

Abstract: A water monitoring and regulation apparatus comprising two vanes connected to two flow meters, a timer, a main gear connected to the two vane shafts, a timer gear connected to the timer, a shut off mechanism, a manual reset and an automatic reset when the shut off has not been engaged. The flow of water through the vanes causes the main gear to turn which causes the timer gear to turn. When the timer gear has turned the number of revolutions corresponding to the pre-selected maximum flow time, the timer will shut off the flow of water. When the water flow is interrupted, as in normal use of the water supply, the time will be automatically reset by the reset mechanism.

Abstract: A system for monitoring a water consuming structure in an individual unit of a multi-unit building, comprising means for determining that volumetric flow through the pipe proximate the water consuming structure has been continuous during a predetermined period of time, the predetermined time being selected to be greater than a period of time during which water should be flowing continuously through the pipe, and means for transmitting an alarm signal in the event that it is determined that flow to the water consuming structure has been continuous for the predetermined time.

Abstract: A system and method are provided for supplying a predetermined amount of fluid, such as fuel and more specifically natural gas, to a target delivery site along at least two pipeline segments wherein a predetermined number of flow meter assemblies corresponding to a total of the at least two pipeline segments are provided to meter flow to the site. The flow meter assemblies are disposed in parallel for flowing a respective portion of the total flow to the target delivery site.

Abstract: The present invention includes a method for multiphase metering of multiphase flow. the method begins with reducing gas volume to about 20% or less, then pumping the flow stream through two meters, a cut meter and a mass flow meter, arranged in series. Computations may be made on the flow stream to determine net oil rate, water cut, and gas fraction in the flow stream.

Abstract: The invention provides materials and methods for modeling human blood vessels. Including panels of anatomically accurate vascular phantoms, such as carotid artery phantoms, comprising a range of stenotic conditions and other geometric variations; methods of making anatomically accurate vascular phantoms using stereolithography with an input data set representation of a natural vascular lumenal surface to construct an anatomically accurate vascular phantom comprising a physical representation of the surface; and methods of using the subject phantoms and panels of phantoms, such as methods of measuring a parameter of fluid flow through a panel of anatomically accurate vascular phantoms comprising a range of stenotic conditions.

Abstract: The device for metering the volume of gas flowing in a pipe, downstream from an expander-regulator, comprises in succession a flow straightener, a velocity-measuring flowmeter, and a silent flowrate limiter. The straightener comprises a support ring in which there are mounted a first perforated plate having holes distributed over its surface, together with a first porous plate and a spacer in the form of an annulus co-operating with the first perforated plate. The limiter comprises an upstream web defining a second perforated plate perforated by a defined number of calibrated holes, the total flow section thereof being much less than the total flow section of the first perforated plate, a second perforated plate, and a downstream web defining a third perforated plate having holes of total flow section that is much greater than the total flow section of the second perforated plate of the upstream web.

Abstract: A system for monitoring the volume rate of flow and total volume of liquid being drawn from a supply by way of a plurality of discharge conduits includes a flow meter transducer for associated individually with each of the discharge conduits with the transducers providing pulse information to associated flow meter circuits that are connected in series relationship with one another and to a master control module. Each of the individual flow meter circuits includes a pair of microprocessors, one for determining from the pulse information of its associated transducer the volume rate of flow of liquid out its associated discharge conduit. The second microprocessor is programmed to combine the flow information from its own transducer with combined flow information from an adjacent upstream flow meter circuit in the series string and produces a combined flow output signal for delivery to an adjacent downstream flow meter circuit.

Abstract: A method and apparatus for metering building structures having a plurality of service outlets each having control valves, includes the installing of meters within a given distance from each one of the valves. A transmission system is coupled electrically to each one of the meters for sending meter readings periodically to a remotely located equipment.

Abstract: A method of operating a municipal water system employs a master computer having a memory which retains information regarding all the valves in the system. One assigned to exercise certain valves in the system obtains a print out of current information regarding the valves to be exercised from the computer. A valve turning machine which is controlled by a hand held computer is provided to the operator and after the operation exercises the assigned valves, information stored in the hand held computer is down loaded into the memory of the master computer to thereby update the municipal recorder.

Abstract: An apparatus for volume determination in a pump unit for fluid, such as fuel, in which a first and a second metering means are provided which are juxtaposed. The metering means each comprise a metering casing having a shaft assembly, which is adapted to be rotated when fluid flows through the metering casing. Each metering means further comprises a pulse generating means, which has a frequency generator and a pulse generator and which is adapted to convert the rotation of the shaft assembly into pulses. The frequency generator is connected to the shaft assembly for rotation therewith, mounted in the respective metering casings. The two pulse generators are adapted to sense, in a contactless manner, rotation of the respective frequency generators and to emit pulses in relation thereto. The two pulse generators are arranged in a separate pulse generator module and are encompassed in a pulse generator casing, which is detachably connected to the metering casing.

Abstract: A system for monitoring the use of heat energy in water devices in an individual unit of a multi-unit complex wherein the multi-unit building is supplied water from a common source and the individual unit has a plurality of energy consuming water devices each supplied by supply and return water pipes supplied from said common source. The system comprises a monitor for monitoring the flow through each of the water pipes which will determine that successive volumetric flow units have flowed through the pipe, define the heat energy of each of the successive volumetric flow units, and compute a total heat energy removed from the successive volumetric flow units, and periodically transmits the total heat energy consumed from the successive volumetric flow units, and a remote receiver which receives the total heat energy transmitted from each of the plurality of monitors and computes a total heat energy use for the individual unit for a selected period of time.

Abstract: A mini-diluter apparatus and method are provided for preparing dilute samples of exhaust gas for emission testing. The apparatus includes first and second mass flow controllers which respectively control the mixing of exhaust gas and diluent gas samples at a constant ratio. The mixture is fed at a pressure, controlled by a back pressure regulator, to a third mass flow controller. This third controller provides a controlled sample rate (normally proportional to exhaust flow from an engine under test) to a bag sample system, or other sampling system, with excess mixture being exhausted through a pressure regulator to atmosphere. Improved accuracy and reduced calibration complexity are results of the improved apparatus and method.

Abstract: Apparatus to measure the calorific value and/or the Wobbe index of fuel gas supplied along a pipe. A control can operate two outlet valves and cause an inlet valve to be locked in a closed position or be unlocked to stay in a normally open state until the gas pressure in a chamber of predetermined volume reaches a preset pressure difference above the pressure in the pipe. Under direction of the control, a pump moves fuel gas from the pipe into the chamber whilst the outlet valves are closed. Once the pressure in the chamber attains the preset difference, the inlet valve closes automatically to be held locked closed by the control. Certain properties of the gas in the chamber, such as thermal conductivity, specific heat capacity and speed of sound, are measured and corrected to STP conditions. The pump moves two samples of gas into the chamber at two sequential times, each time until the gas pressure therein attains the preset value and the inlet valve again closes automatically in a locked position.

Abstract: A metering pipe for a landfill well includes an upstream segment and a downstream segment. A coupling having an orifice plate positioned therein surroundingly engages both segments. Specifically, the segments are advanced into the coupling toward each other, on opposite sides of the orifice plate from each other. Upstream and downstream pressure ports are respectively formed through the walls of the upstream and downstream segments and the coupling adjacent the orifice plate. The difference in pressure at the ports is correlated to a flow rate through the pipe. To ensure that all gas flowing through the well also flows through the metering pipe, a compression coupling is disposed between the metering pipe and well. The compression coupling joins the metering pipe to the well and blocks gas flow past the outside of the metering pipe, while permitting the metering pipe to be selectively reciprocated relative to the well.

Abstract: A cryogenic meter is mounted in an insulated container having an inlet and outlet in circuit with the LNG delivery flow path. The container is filled with LNG to a level above the cryogenic meter to pre-cool it to a desired operating temperature. To maintain the level of LNG in the container during use and to separate vapor from liquid, a float device allows vapor to be returned to the storage tank from the container to refill it with LNG. Because the meter is continuously immersed in LNG during use, it is maintained at a constant temperature permitting the quantity of LNG delivered to a use device to be accurately metered. Temperature and/or pressure signals are sent to a microprocessor which computes the density of the LNG and displays the metered amount of LNG on a display.

Abstract: Disclosed is an apparatus having a plurality of interfaces, each corresponding to one of a plurality of MFCs which provide voltage signals corresponding to the control voltages controlling the MFCs; a plurality of wires for transmitting the voltage signals from the interfaces; a position switch coupled to the plurality of wires for selecting voltage signals corresponding to one of the MFCs; and a plurality of displays coupled to the switch for providing a visual display of the values of said voltage signals corresponding to one of the MFCs. The invention enables an operator to monitor/calibrate a plurality of MFC operating voltages simultaneously without interfering with other operations of a system using MFCs.

Abstract: A meter is provided for measuring the volumetric flow of a fluid in a conduit. The meter comprises a pair of turbine assemblies. Each of the turbine assemblies are adapted to have a speed of rotation representative of a volumetric fluid flow that is independent of the other turbine assembly. A flow randomizer is located between the pair of turbine assemblies. The flow randomizer is operable to eliminate substantially all flow effects of one of the turbine assemblies upon the other turbine assembly. Means are provided for transducing the speed of rotation of at least one of the turbine assemblies.

Abstract: A system and method for simultaneous measurement of thermal conductivity and the mass flow of a fluid comprising two conduits arranged in a concentric or bypass arrangement through which the fluid is flowing, a pyroelectric anemometer disposed within each of the two conduits, and a differential amplifier connected to each of the pyroelectric anemometers which generate a signal based upon flow of fluid through the conduits.

Abstract: An apparatus and method for measuring the flow rates of each component of two-phase flow consisting of a gas and a liquid or three-phase flow consisting of water, oil and gas, including a first volumetric flow meter stage, and second and third momentum flow meter stages coupled in a series flow path with the volumetric flow meter stage and in which a velocity ratio between the gas and the liquid in the series flow path is maintained to be one. A processor calculates flow rates of the components of flow by solving volumetric flow and momentum or energy equations defining flow through the first through third stages utilizing a volumetric flow output from the first stage and momentum flux outputs from said second and third stages, and an indicator displays flow of liquid and gas or oil, water and gas components of the flow. To measure three-phase flow, a water-cut meter is provided to determine the amount of water flow, which is then used by the processor to determine the flow of the rest of the liquid.

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 flowmeter comprises an output cut-off circuit controlled by a command signal generated by a flow switch, wherein the flow switch generates a command signal switching on the transmission of an electrical signal representing the flow rate of media to an output terminal, when the flow rate of media being measured by the flowmeter is greater than a preset threshold value, and switches off the transmission of the electrical signal representing the flow rate of media to the output terminal, when the flow rate of media is less than the preset threshold value.

Abstract: The average volumetric velocity U.sub.m of a fluid flowing within a large industrial flue stack is determined by a combination of measurement and calculation techniques. The temperature, velocity head and static pressure of the stack fluid are measured at two points within the bounded path of the flue stack. The flight time of a random acoustic noise wave is measured in both the upstream and downstream directions. The path average velocity U.sub.p is determined from the measured values of the upstream and downstream flight times. The fluid velocity is determined using the measured values of the flight times, the fluid temperature, velocity head and static fluid pressure. The determined values of the path average velocity U.sub.p and the fluid velocities are used to determine the average volumetric velocity U.sub.m. A curve fitting algorithm is employed to determine an approximation of the actual fluid flow distribution across the bounded path, and this approximation is used to calculate U.sub.m.

Abstract: A temperature time-of-flight (TOF) sensor is combined with a nozzle of known flow area to create a TOF flowmeter. The TOF measured by the flow sensor provides a measure of gas volumetric flow rate. A TOF sensor has of a pulse heated wire and a single temperature sensor downstream of the wire. This single temperature sensor arrangement allows the accurate measurement of gas velocities much lower than the previously demonstrated limit of 0.3 m/s. The TOF sensor combined with a nozzle creates a new device such that the TOF measured with this device provides a measure of the gas flow rate rather than just the gas velocity. More than one nozzle in series is combined to achieve high flow measuring ranges. Compensation for variations in the thermophysical properties of the gas being metered is provided by pulsing the heated wire and measuring sensor outputs when both are immersed in the gas at zero velocity.

Abstract: The present invention provides a wide range fluid flowmeter, having a body with a central air flow passage and a target in the air flow passage to direct fluid flow to one of the first and second flow loops. The fluid alternates between the first and second flow loops to create an oscillatory system, whose frequency can be measured to determine fluid flow rate. A preferred frequency measuring device is a piezoelectric diaphragm provided within the body of the flowmeter. In a preferred embodiment, a low flow rate sensor is provided in a nozzle of the flowmeter proximal the inlet to the body of the oscillatory, high flow rate flowmeter. The low flow rate sensor can incorporate a convection system which measures flow rates beyond the lower scale of the oscillatory flowmeter, thereby providing an apparatus and a method for measuring flow rates in a compact flowmeter, and with greater efficiency than previous apparatuses and methods.

Abstract: A method and apparatus for measuring a base condition volumetric flowrate of a pipeline gas flowing through a pipeline in which a pipeline gas flowrate is measured by a pipeline gas flowmeter that responds to density in a characteristic manner, a sample gas flowrate is measured by a sample gas flowmeter that responds to density in the same manner as a pipeline gas flowmeter, and a base condition sample gas volumetric flowrate is measured by measuring the base condition energy flowrate of the sample gas, measuring the base condition heating value of the sample gas and dividing the base condition energy flowrate by the base condition heating value. The measured pipeline gas flowrate through the pipeline is then adjusted by the ratio of the base condition sample gas flowrate divided by the measured flowrate of the sample gas. The temperature of the sample gas should be substantially the same as the pipeline gas in the pipeline when the sample gas flowrate is measured.