Abstract: The invention makes it possible to measure, in real time, the flow of a fluid that is incompressible while having an unsteady flow. The pressure measuring system is primarily comprised of a negative-pressure element (1) placed within the flow and provided with two wall pressure taps (A, B). A means (2) for measuring a pressure difference connected to the pressure taps (A, B) enables the following formula to be solved: dq(t)/dt+?(q(t))=?×?p(t) directly stemming from fundamental equations of fluid mechanics and/or: ?p(t) represents the pressure difference measured by the sensor; q(t) represents the sought volume flow rate, and; ? represents a function of the geometry of the negative-pressure element, of the fluid and of the flow q(t), the particularity of this formula being the consideration of the direction of flow in the second term of the left member of the formula.

Abstract: A sampling system includes a collection module including a gas handler, and a flow controller in communication with the gas handler of the collection module. The flow controller controls the gas handler to move a selected volume of gas through the collection module.

Abstract: In one approach, a method for measuring exhaust gas recirculation flow in an engine is provided. The method comprises separating EGR flow into at least a first flow and a second flow, passing the separated first flow through a restriction region, where the first flow passes through the restriction region separately from the separated second flow, combining the separated second flow and inducting the combined flows into a cylinder of the engine, where the EGR flow is separated and then combined within a common EGR passage.

Abstract: An apparatus for measuring velocity of a fluid passing through a pipe is provided. The apparatus includes a spatial array of sensors having at least two sensors disposed at different axial locations along the pipe, wherein the sensors provide at least one signal indicative of a stochastic parameter associated with a characteristic of the fluid, wherein the characteristic includes at least one of unsteady temperature, density, consistency, transparency, conductivity, capacitance, resistivity, and inductance. A signal processor is also provided, wherein the signal processor is configured to receive the at least one signal and determine the velocity of the fluid using the at least one signal.

Abstract: A method for determining one or more fluid flow parameters for a fluid flowing within a pipe is provided. The fluid is a mixture of solid particles and gas. The method includes the steps of: a) providing a meter operable to determine the velocity of the fluid flow through the pipe, which meter is substantially insensitive to the particulate/gas mass ratio of the fluid flow; b) determining the velocity of the fluid flow within the pipe using the meter; and c) determining a particulate/gas mass ratio using a density value for the gas within the flow and the determined fluid flow velocity.

Abstract: An apparatus for monitoring fuel filter performance and transmitting performance information. The performance information may be transmitted wirelessly to a computer or a wireless telephone and then transmitted to a technician. The performance information is preferably transmitted with location information which identifies the location of the filter for which maintenance is required. The information may also be transmitted to a web server which can store the information in a database and also send information via text messaging or telephone voice transmission or other automatic electronic transmission mechanism.

Abstract: To perform a non-destructive condition assessment of a pipe carrying a fluid, an actual value representative of the propagation velocity of an acoustic disturbance propagating between two longitudinally separated points on the pipe is determined. A corresponding predicted value for the propagation velocity is computed as a function of at least one wall thickness parameter of the pipe by using a theoretical model for the propagation of acoustic waves in the pipe that assumes said pipe has a finite wall thickness with a predetermined circumferential thickness profile. The wall thickness parameter is then computed by matching the actual value with the predicted value, for example, by substituting the actual value in a formula predicting the theoretical value.

Abstract: A gaseous fuel injector 3 supplies gaseous fuel from a compressed gas cylinder 1 into a measuring portion thin tube 5 and pressure change in the tube is measured by a pressure measuring device 4 through a small hole provided in the thin tube 5. An extension thin tube 6 for removing the influence of reflected waves is provided on the downstream side of the measuring portion thin tube 5. There is provided at the downstream side end of the extension thin tube a back pressure valve 13 for uniformly increasing the pressure in the tube and for bringing the pressure close to the actual environment in the engine cylinder. Also, a tapered-shape nozzle is arranged in the measuring portion thin tube 5. Pressure measured by the pressure measuring device 4 is transduced into mass flow rate in the thin tube according to a predetermined calculation formula. Accordingly, it is possible to measure instantaneous mass flow rate of gaseous fuel injected from the gaseous fuel injector.

Abstract: An apparatus, system, and method are disclosed for differential pressure measurement across a fluid conduit flow area change. The apparatus may include a particulate filter, a differential pressure sensor, and a fluid conduit size change downstream of the particulate filter. The apparatus may include a tube configured to place the downstream differential pressure sensor port in fluid contact with a uniform flow region of the fluid conduit downstream of the particulate filter. An apparatus is thereby provided to measure differential pressure across a fluid conduit flow area change such that the differential pressure measurement is minimally affected by the change in flow characteristics induced by the change in cross-sectional flow area.

Abstract: A process variable transmitter for measuring a process variable of a process fluid in a vessel includes first and second pressure couplings arranged to receive a first pressure and a second pressure of process fluid in the vessel. These pressures are related to the density of the process fluid. A sensor provides a sensor output related to the process fluid in the vessel. Measurement circuitry is configured to calculate a calculated process variable of the process fluid in the vessel based upon the first and second pressures and the sensed process variable.

Abstract: A process pressure fluid transmitter is coupled to a differential pressure producer and measures a differential pressure across the producer. A statistical parameter is calculated upon successive differential pressure indications, and the calculated parameter is used to indicate wet gas flow. The indication can be generated locally at the process pressure transmitter, communicated via a wired process communication loop, communicated wirelessly, or any combination thereof.

Abstract: The invention relates to a new method and a new apparatus to accurately measure flow rates in injection systems such as gasoline, direct injection gasoline and diesel downstream of the injector where the fuel (liquid in general) is discharged from a nozzle (e.g. an injector). More specifically, it measures the flow velocities and volumetric flow rates in highly transient flows discharged cyclically with injection duration within a few hundred microseconds. Moreover, it is able to resolve multiple injection shots produced within an engine cycle with high volumetric (0.01 mm3) and temporal (10 ?s) sensitivities. The main uses of this instrument in automotive industry are manufactures of FIE, injection test machines and injection diagnostic systems. In other industries the uses maybe represented by measuring and controlling of highly transient flows with a need to accurately perform quantitative flow data in wide range of timing and dosing.

Abstract: An integrated DPF loading and failure sensor with two particulate matter sensors one located upstream of the filter and the other located downstream of the filter. The sensors are integrated into the leading and trailing edges of the filter. Integrating two particulate matter sensors with the DPF will allow the proper interval between reconditioning of DPF, since the particulate matter collected on the filter is measured and not estimated. The upstream sensor determines the amount of particulate matter entering the filter. In addition to using the first sensor for loading, the second sensor, at the trailing face of the filter, can be used to determine break-through of the DPF. The second sensor measures the particulate matter escaping the filter.

Abstract: A method and system for generating an uncertainty value. At least some of the illustrative embodiments are systems comprising a device in fluid communication with a conduit, and a flow computer electrically coupled to the device. The flow computer is configured to generate a flow value based on parametric data, and the flow computer is configured to generate an uncertainty value of the flow value based on the parametric data and on an accuracy value received from the device.

Abstract: A flow sensor has an inlet chamber with a first pressure sensor and an inlet port for receiving fluid, and an outlet chamber with a second pressure sensor and an outlet port. The flow sensor also has an anemometer in fluid communication with at least one of the two chambers.

Abstract: An industrial pressure transmitter, for use in industrial process control systems, comprises a differential pressure sensor and an integrated process connector connected to the differential pressure sensor. A process fluid flow duct extends through the process connector and receives an industrial process fluid. A primary element is positioned in the process fluid flow duct for producing a pressure differential in the process fluid across the primary element. The differential pressure sensor is connected to the process fluid flow duct to sense the pressure differential across the primary element.

Abstract: A method and apparatus for measuring wetness of a gas flow within a conduit is provided that includes a first pressure sensor, a second pressure sensor, a sonar based flowmeter, and a processing device. The first pressure sensor is operable to sense the pressure of the gas flow within the conduit at a first position. The second pressure sensor is operable to sense the pressure of the gas flow within the conduit at a second position. The second position is located downstream of the first position an amount sufficient that the gas flow experiences a pressure drop. The sonar based flowmeter is configured to determine a volumetric flow rate of the gas flow. The processing device is in communication with the first and second pressure sensors and the sonar based flowmeter. The processing device is adapted to determine a difference in the pressure sensed by the first and second pressure sensors, and to determine the wetness of the gas flow using the difference in pressure and the volumetric flow rate.

Abstract: Provided are an orifice member, and a differential-pressure flow meter and a flow-regulating device using the orifice member, that allow purging to be carried out easily when changing the fluid to be circulated, that are less likely to cause contamination and leaching of impurities to the circulated fluid, and that can be easily produced. The flow-regulating device includes a first pressure-measuring device (object to be connected to) that is connected to one end of the orifice member, and a second pressure-measuring device (object to be connected to) that is connected to the other end of the orifice member, and a flow-regulating valve that is connected to the downstream side of the differential-pressure flow meter, which includes the above-mentioned units.

Abstract: A method and apparatus for measuring a parameter of a wet gas flow is provided, wherein the apparatus includes a differential pressure based flow meter configured to determine a first volumetric flow rate of the wet gas flow. Additionally, the apparatus includes a sonar based flow meter configured to determine a second volumetric flow rate of the wet gas flow. Furthermore, the apparatus includes a processing device communicated with at least one of the differential pressure base flow meter and the sonar based flow meter, wherein the processing device is configured to determine the parameter (e.g., wetness, volumetric gas flow rate, and volumetric liquid flow rate) of the wet gas flow using the first and second volumetric flow rates.

Abstract: The invention relates to a dynamic pressure probe for universal use, which enables different types of mounting of the connection lines without complex adapters and/or round arches. The dynamic pressure probe comprises a probe head inside of which channels run, which lead to the part of the probe that, during a measurement, is located in the medium to be measured, and which lead to adapters mounted on the probe head, said probe head having a rectangular cross-section. The axes of the channels are located on the diagonals that run between two corners of the probe head, and the channels can be reached from two outer surfaces of the probe head via transversal boreholes.

Abstract: An isokinetic testing machine is disclosed having a support frame, a sub-assembly disposed on the support frame, a power source operably disposed within the sub-assembly, a first main arm having a proximal apex end and a distal end, the first main arm distal end is pivotally attached to the power source, a first torque arm pivotally and releasably attached to the first main arm proximal apex end, a user support area disposed on the support frame proximate to the first torque arm proximal end, a first load cell disposed within the first torque arm for measuring the torque when the first torque arm pivots, and wherein the first main arm and the torque arm can pivot and are configured to a desired position for isokinetic testing of the knees, the shoulders, and the back of the user.

Abstract: The invention relates to a method and a device for monitoring a fluid flow delivered by means of a pump. In the method the pressure distribution of the fluid is continuously or quasi-continuously measured as actual values in partial areas of the pump stroke and compared with desired values. In the device at least one pressure sensor is provided for the continuous or quasi-continuous measurement of the pressure of a fluid at least in partial areas of the pump stroke and a comparator is provided for comparing the measured actual values of the pressure with desired values.

Abstract: Metering apparatus including wall portions which define an elongate generally upright cavity of substantially uniform cross-section and an inlet to the cavity to enable fluid which is to be metered to be fed into the cavity. The apparatus further includes a pressure transducer in communication with fluid in the cavity when the apparatus is in use, to provide a signal indicative of the amount of fluid in the cavity above the transducer.

Abstract: An air flow measurement device includes an air pipe securely formed inside the cylindrical tube, a first measuring tube securely formed inside the cylindrical tube and having a first open end located at an inner side face of the air pipe so as to measure radial pressure of air flowing through the air pipe and a second open end extending out of the cylindrical tube. An L shaped measuring tube is securely formed inside the cylindrical tube and has a first open end located at the inner side face of the air pipe so as to measure axial pressure of air flowing through the air pipe and a second open end extending out of the cylindrical tube.

Abstract: The present invention provides a system for determining blood flow rate in a vessel which communicates blood between two locations of a patient, the system comprising: a conduit in fluid communication with the vessel; at least one sensor in communication with the vessel for determining differential blood pressure (? P) between two or more locations within the vessel; and a processor operably connected to the at least one sensor for processing the ? P to obtain blood flow rate within the vessel. A method for determining blood flow rate in a vessel which communicates blood between two locations of a patient, the method comprising: diverting blood from the vessel at a diversion point to obtain a flow of diverted blood in a conduit; determining differential blood pressure (? P) of the diverted blood through the conduit; and processing the ? P to obtain blood flow rate within the vessel.

Abstract: A apparatus 10, 110 is provided that measures the speed of sound and/or vortical disturbances propagating in a fluid or mixture having entrained gas/air to determine the gas volume fraction of the flow 12 propagating through a pipes and compensating or correcting the volumetric flow measurement for entrained air. The GVF meter includes and array of sensor disposed axially along the length of the pipe. The GVF measures the speed of sound propagating through the pipe and fluid to determine the gas volume fraction of the mixture using array processing. The GVF meter can be used with an electromagnetic meter and a consistency meter to compensate for volumetric flow rate and consistency measurement respective, to correct for errors due to entrained gas/air.

Abstract: A method for determining the volume of an incompressible gas in a system including incompressible substances in a zero-gravity environment. The method includes inducing a volumetric displacement within a container and measuring the resulting pressure change. From this data, the liquid level can be determined.

Abstract: A process variable transmitter for measuring a process variable of a process fluid in a vessel includes first and second pressure couplings arranged to receive a first pressure and a second pressure of process fluid in the vessel. These pressures are related to the density of the process fluid. A sensor provides a sensor output related to the process fluid in the vessel. Measurement circuitry is configured to calculate a calculated process variable of the process fluid in the vessel based upon the first and second pressures and the sensed process variable.

Abstract: A flow meter with a metering device for intaking and metering a defined volume of a fluid, and with a control unit for controlling the fluid intake of the metering device for determining a flow rate of the fluid.

Abstract: A portable flow measuring apparatus includes an array of pressure sensors used to measure the acoustic and convective pressure variations in the flow to determine a desired parameter. A portable processing instrument processes the signals provided by the sensing array to provide an output signal indicative of a parameter of the fluid flow. The portable processing instrument includes a processor having appropriate processing algorithms to determine the desired or selected parameter(s) of the process flow 12. The portable processing instrument has a user interface to permit the user to select the parameters to be measured in the process flow, and/or more importantly, to enable the user to modify particular parameters or functions in the processor 30 and/or processing algorithms. The user interface 32 also enables a user to modify the code of the algorithm via a graphic user interface (GUI), keyboard and/or user input signal 34.

Abstract: The invention relates to a new method and a new apparatus to accurately measure flow rates in injection systems such as gasoline, direct injection gasoline and diesel downstream of the injector where the fuel (liquid in general) is discharged from a nozzle (e.g. an injector). More specifically, it measures the flow velocities and volumetric flow rates in highly transient flows discharged cyclically with injection duration within a few hundred microseconds. Moreover, it is able to resolve multiple injection shots produced within an engine cycle with high volumetric (0.01 mm3) and temporal (10 ?s) sensitivities. The main uses of this instrument in automotive industry are manufactures of FIE, injection test machines and injection diagnostic systems. In other industries the uses maybe represented by measuring and controlling of highly transient flows with a need to accurately perform quantitative flow data in wide range of timing and dosing.

Abstract: Apparatus and associated systems, methods and computer program products relate to monitoring the performance of an operating gas meter by automatic and substantially continuous differential pressure (dP) measurement. Measured dP may be compared against a baseline dP characteristic to determine if the measured dP exceeds a threshold value above a baseline dP characteristic. If the threshold is exceeded, then the system may generate a signal to request repair or replacement of the meter. After installation, some embodiments collect dP data over time and/or over a range of flow rates to automatically learn a baseline dP characteristic under installation conditions. A system may switch from a default baseline dP characteristic to a learned baseline dP characteristic. Some embodiments may further correct volume or flow rate signals for line pressure and/or temperature. Further embodiments provide a passive apparatus to protect a dP sensor against transients in line pressure and/or differential pressure.

Abstract: Flow rate measurement system includes two measurement regions 14,16 located an average axial distance ?X apart along the pipe 12, the first measurement region 14 having two unsteady pressure sensors 18,20, located a distance X1 apart, and the second measurement region 16, having two other unsteady pressure sensors 22,24, located a distance X2 apart, each capable of measuring the unsteady pressure in the pipe 12. Signals from each pair of pressure sensors 18,20 and 22,24 are differenced by summers 44,54, respectively, to form spatial wavelength filters 33,35, respectively. Each spatial filter 33,35filters out acoustic pressure disturbances Pacoustic and other long wavelength pressure disturbances in the pipe 12 and passes short-wavelength low-frequency vortical pressure disturbances Pvortical associated with the vortical flow field 15. The spatial filters 33,35 provide signals Pas1,Pas2 to band pass filters 46,56 that filter out high frequency signals.

Abstract: A sensor device for use in an automobile as an airflow sensor is composed of a silicon substrate in which a cavity is formed and a base plate bonded to the silicon substrate. An upper end of the cavity is closed with a thin membrane including a sensor element such as a temperature sensor element, while a lower end of the cavity is closed with the base plate. An air passage having a small cross-section is formed through the base plate, so that the cavity communicates with the outside air through the air passage. The thin membrane is prevented from being damaged by collision with foreign particles included in the airflow because the air in the cavity functions as a damper. The air passage may be made in the silicon substrate in parallel to its surface without using the base plate.

Abstract: An internally isothermal control volume of a flow verification system for measuring gas pressure drop relative to time to calculate flow rate has a thermal reservoir provided therein. The thermal reservoir is de-coupled from ambient effects so that the temperature of the thermal reservoir will be driven to the gas temperature during steady state flow of gas through the known volume and during gas expansion, will transfer heat to maintain a contrast gas temperature for accurate gas flow rate calculation with minimal effect from external influence during the verification process.

Abstract: A sensor head characterizes unsteady pressures in a fluid flowing within a pipe, as may be caused by one or both of acoustic waves propagating through the fluid within the pipe and/or pressure disturbances that convect with the fluid flowing in the pipe. The sensor head comprises a rigid support structure and at least one transducer attached to the rigid support structure. The rigid support structure holds the transducer in contact with an outer surface of the pipe. The at least one transducer senses relative movement between the outer surface of the pipe and the support structure and provides a signal indicative of unsteady pressures within the fluid at a corresponding axial position of the pipe in response to the relative movement. The support structure may be attached to each transducer in an array of transducers, and may include a handle secured thereto for manipulating the sensor head into contact with the pipe.

Abstract: A apparatus 10,110 is provided that measures the speed of sound and/or vortical disturbances propagating in a fluid or mixture having entrained gas/air to determine the gas volume fraction of the flow 12 propagating through a pipes and compensating or correcting the volumetric flow measurement for entrained air. The GVF meter includes and array of sensor disposed axially along the length of the pipe. The GVF measures the speed of sound propagating through the pipe and fluid to determine the gas volume fraction of the mixture using array processing. The GVF meter can be used with an electromagnetic meter and a consistency meter to compensate for volumetric flow rate and consistency measurement respective, to correct for errors due to entrained gas/air.

Abstract: A device for measuring the volume flow or other substance properties of a gas, whose direction of flow can reverse. The arrangement contains a specially designed Y-piece, which is used for branching into direction-dependent flow paths and can be used at the same time for the measurement. Such devices can be preferably used in the area of mechanical respiration.

Abstract: An apparatus and method are disclosed wherein at least one parameter associated with a core-annular flow (CAF) in a pipe is measured by sensing unsteady pressures associated with undulations formed at the interface of a core region and an annular region in the CAF at different axial locations along the pipe. The at least one parameter, which may include a flow velocity of the CAF, Mach number associated with the CAF, and a volumetric flow rate of the CAF, is determined using sensed unsteady pressures. The CAF may be developed from a shear thinning fluid, such as bitumen froth or from a wood pulp fiber suspension. Alternatively, the CAF may be developed from a lubricating fluid, such as water, and a fluid to be transported, such as oil, where the fluid to be transported forms the core region and the lubricating fluid forms the annular region.

Abstract: An apparatus measures the speed of sound and/or vortical disturbances propagating in a fluid flow to determine a parameter of the flow propagating through a pipe. The apparatus includes a sensing device that includes an array of pressure sensors used to measure the acoustic and convective pressure variations in the flow to determine a desired parameter. The sensing device includes a unitary strap having a plurality of bands disposed parallel to each other. The bands are interconnected by cross members to maintain the bands a predetermined distance apart. Each of the bands having a strip of piezoelectric film material mounted along a substantial length of the bands. The piezoelectric film material provides a signal indicative of the unsteady pressures within the pipe. The sensing device includes a conductive shield around the multi-band strap and the piezoelectric film material to provide a grounding shield.

Abstract: A pressure sensor includes a silicon-on-insulator (SOI) substrate, a glass substrate bonded to the SOI substrate by anode bonding, a silicon island formed on a part of a silicon layer of the SOI substrate and surrounded by a groove extending to an insulating layer of the SOI substrate, a through hole formed in the glass substrate, and an output electrode that is made of a conductive material, is disposed inside the through hole, and is electrically connected to an electrode formed on the glass substrate via the silicon island.

Abstract: A portable flow measuring apparatus measures the speed of sound and/or vortical disturbances propagating in a fluid flow to determine a parameter of the flow propagating through a pipe. The apparatus includes a sensing device that includes an array of pressure sensors, which may be removable, used to measure the acoustic and convective pressure variations in the flow to determine a desired parameter. A portable processing instrument processes the signals provided by the sensing array to provide an output signal indicative of a parameter of the fluid flow. The portable processing instrument includes a processor having appropriate processing algorithms to determine the desired or selected parameter(s) of the process flow 12. The portable processing instrument has a user interface to permit the user to select the parameters to be measured in the process flow, and/or more importantly, to enable the user to modify particular parameters or functions in the processor 30 and/or processing algorithms.

Abstract: A variable differential adjustor for a fluid pressure-actuated switch, with the fluid, in the preferred form of the invention, being air. The restrictor has a restrictor housing with a fluid passage in which a restrictor plug, typically a set screw, is engaged. By judicious adjustment of the position of the set screw, fluid flow to and from a pressure-actuated switch is controlled, controlling when the switch is activated to control apparatus such as a sump pump, and when the switch is deactivated.

Abstract: Systems and methodologies that provide for multi-parameter sensing via micro fabricated sensing structures operatively connected to oscillators, each micro-fabricated sensing structure in part defines a frequency of a respective associated oscillator. Output from such oscillators can be combined together, and then AC coupled with an incoming DC voltage that feeds the oscillators. The wiring arrangement includes two conducting paths/wires that carry a direct current to the oscillators as well as outputting the combined signal to external measurement devices. In addition, arrangements for pressure sensors are provided that mitigate errors from temperature variations and the induced stress/strains.

Abstract: A system of measuring the flow of a human or animal bodily action or fluid along or through a bodily flow conduit using two or more sensor means located on the body and along or around the path of the conduit is described. Bodily fluids whose flow is measurable by the present invention include blood, semen and urine. The present invention is a non-invasive way of measuring the flow of a bodily action or fluid along or through a conduit, such as pulse wave velocity. Pulse wave velocity in the brachial artery can provide an indication of vessel wall quality or stiffness, which in turn, can be used to indicate how an individual's vascular system is ageing. Disorders such as stenosis and complete occlusion can be diagnosed by accurate measurement of pulse wave velocity.

Abstract: A sensor for redundantly measuring gas flow has a housing suitable for being interposed in a gas flow conduit. The housing has an orifice through which the gas to be measured flows. A gas flow measuring, hot wire anemometer is positioned in the housing proximate to the orifice for providing a first measurement of the gas flow in the conduit. A first absolute pressure sensor measures gas pressure downstream of the orifice. The first pressure sensor may provide pressure compensation to the anemometer. A second absolute pressure sensor measures gas pressure upstream of the orifice. The first pressure sensor may be further used with the second pressure sensor to obtain a differential pressure measurement providing a further measurement of the gas flow in the conduit that is redundant to that of the anemometer.

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: A bi-directional, clean or grey medium, wide temperature range, low intrusion, low turbulence, mass flow meter extends multiple pressure sensing tubes, each containing multiple pressure sensing ports, into a bounded path a distance no more than one half the diameter of the path, or semi-traversing. These sensing tubes sense impact or static pressures to obtain a sensing pressure, and are in fluid communication with a channel located externally of the bounded path which provides a total average sensing pressure for measurement. A series of reference pressure ports are located flush to the wall surface of the bounded path to obtain a reference pressure. These reference ports are in fluid communication with another channel located externally of the bounded path which provides a total average reference pressure for measurement. The difference in total average sensing pressure and total average reference pressure can be measured and used to calculate the average velocity and volume of gas within the bounded path.

Abstract: A multiple mode pre-loadable fiber optic pressure and temperature sensor includes a generally cylindrical structure having at least one compression element, a fiber optic having a Bragg grating in contact with one side of the compression element, a diaphragm in contact with the other side of the compression element, and a fluid port in fluid communication with the diaphragm. According to preferred aspects of the, a groove is provided in at least one compression element for receiving the fiber optic. The sensor is pre-loaded by straining the diaphragm over the adjacent compression element when the cover is attached. The compression element in contact with the diaphragm preferably has a contoured surface contacting the diaphragm and the diaphragm is stretched to match that contour. By varying the contour of the compression element and the thickness of the diaphragm, the dynamic range of the sensor can be changed. The preferred diaphragm has a variable thickness and is made as an integral part of the structure.

Abstract: Flow rate measurement system includes two measurement regions 14,16 located an average axial distance ?X apart along the pipe 12, the first measurement region 14 having two unsteady pressure sensors 18,20, located a distance X1 apart, and the second measurement region 16, having two other unsteady pressure sensors 22,24, located a distance X2 apart, each capable of measuring the unsteady pressure in the pipe 12. Signals from each pair of pressure sensors 18,20 and 22,24 are differenced by summers 44,54, respectively, to form spatial wavelength filters 33,35, respectively. Each spatial filter 33,35 filters out acoustic pressure disturbances Pacoustic and other long wavelength pressure disturbances in the pipe 12 and passes short-wavelength low-frequency vortical pressure disturbances Pvortical associated with the vortical flow field 15. The spatial filters 33,35 provide signals Pas1,Pas2 to band pass filters 46,56 that filter out high frequency signals.