Abstract: An apparatus is presented for damping an undesired component of an ultrasonic signal. The apparatus includes a sensor affixed to a pipe. The sensor includes a transmitter and a receiver. The transmitted ultrasonic signal includes a structural component propagating through the pipe and a fluid component propagating through a flow in the pipe. The receiver receives one of the transmitted components. The apparatus includes a damping structure. The damping structure dampens the structural component of the ultrasonic signal to impede propagation of the structural component to the receiver. The damping structure includes one of a housing secured to the pipe to modify ultrasonic vibrational characteristics thereof, a plurality of film assemblies including a tunable circuit to attenuate structural vibration of the pipe, and a plurality of blocks affixed to the pipe to either reflect or propagates through the blocks, the undesired structural component of the ultrasonic signal.

Abstract: A method and apparatus for damping an ultrasonic signal propagating in the wall of a pipe, the apparatus including at least one damping structure for securing at least one sensor to the wall of the pipe, wherein the at least one sensor includes a transmitter component and a receiver component for transmitting and receiving an ultrasonic signal, wherein the at least one damping structure is associated with the outer wall of the pipe for damping the ultrasonic signal propagating within the wall of the pipe and a processor that defines a convective ridge in the k-? plane in response to the ultrasonic signals, and determines the slope of at least a portion of the convective ridge to determine the flow velocity of the fluid.

Abstract: A method and apparatus for damping an ultrasonic signal propagating in the wall of a pipe, the apparatus including at least one damping structure for securing at least one sensor to the wall of the pipe, wherein the at least one sensor includes a transmitter component and a receiver component for transmitting and receiving an ultrasonic signal, wherein the at least one damping structure is associated with the outer wall of the pipe for damping the ultrasonic signal propagating within the wall of the pipe and a processor that defines a convective ridge in the k-? plane in response to the ultrasonic signals, and determines the slope of at least a portion of the convective ridge to determine the flow velocity of the fluid.

Abstract: A apparatus 10,110,170 is provided that measures the speed of sound and/or vortical disturbances propagating in a single phase fluid flow and/or multiphase mixture to determine parameters, such as mixture quality, particle size, vapor/mass ratio, liquid/vapor ratio, mass flow rate, enthalpy and volumetric flow rate of the flow in a pipe, by measuring acoustic and/or dynamic pressures. The apparatus includes a spatial array of unsteady pressure sensors 15-18 placed at predetermined axial locations x1-xN disposed axially along the pipe 14. The pressure sensors 15-18 provide acoustic pressure signals P1(t)-PN(t) to a signal processing unit 30 which determines the speed of sound amix propagating through of the process flow 12 flowing in the pipe 14. The pressure sensors are piezoelectric film sensors that are mounted or clamped onto the outer surface of the pipe at the respective axial location.

Abstract: A large diameter optical waveguide, grating, and laser includes a waveguide having at least one core surrounded by a cladding, the core propagating light in substantially a few transverse spatial modes; and having an outer waveguide dimension of said waveguide being greater than about 0.3 mm. At least one Bragg grating may be impressed in the waveguide. The waveguide may be axially compressed which causes the length of the waveguide to decrease without buckling. The waveguide may be used for any application where a waveguide needs to be compression tuned. Also, the waveguide exhibits lower mode coupling from the core to the cladding and allows for higher optical power to be used when writing gratings without damaging the waveguide. The waveguide may resemble a short “block” or a longer “cane” type, depending on the application and dimensions used.

Abstract: An apparatus and method of processing flow meter data to filter out signal noise is provided. The method includes defining the flow meter data as a k-? plane, wherein the k-? plane includes a first k-plane quadrant separated from a second k-plane quadrant by a predetermined axis. The flow meter data includes a first data set disposed within the first k-plane quadrant and a second data set disposed within the second k-plane quadrant. The first data set and the second data set are disposed symmetrically about the predetermined axis and subtracting the first data set from the second data set to obtain a resultant data set.

Abstract: A large diameter optical waveguide, grating, and laser includes a waveguide 10 having at least one core 12 surrounded by a cladding 14, the core propagating light in substantially a few transverse spatial modes; and having an outer waveguide dimension d2 of said waveguide being greater than about 0.3 mm. At least one Bragg grating 16 may be impressed in the waveguide 10. The waveguide 10 may be axially compressed which causes the length L of the waveguide 10 to decrease without buckling. The waveguide 10 may be used for any application where a waveguide needs to be compression tuned, e.g., compression-tuned fiber gratings and lasers or other applications. Also, the waveguide 10 exhibits lower mode coupling from the core 12 to the cladding 14 and allows for higher optical power to be used when writing gratings 16 without damaging the waveguide 10. The shape of the waveguide 10 may have other geometries (e.g.

Abstract: A apparatus 10,110,170 is provided that measures the speed of sound and/or vortical disturbances propagating in a single phase fluid flow and/or multiphase mixture to determine parameters, such as mixture quality, particle size, vapor/mass ratio, liquid/vapor ratio, mass flow rate, enthalpy and volumetric flow rate of the flow in a pipe, by measuring acoustic and/or dynamic pressures. The apparatus includes a spatial array of unsteady pressure sensors 15-18 placed at predetermined axial locations x1-xN disposed axially along the pipe 14. The pressure sensors 15-18 provide acoustic pressure signals P1(t)-PN(t) to a signal processing unit 30 which determines the speed of sound amix propagating through of the process flow 12 flowing in the pipe 14. The pressure sensors are piezoelectric film sensors that are clamped onto the outer surface of the pipe at the respective axial location.

Abstract: An optical filter, including a pair of Bragg grating units optically coupled to respective ports of a circulator, is provided for filtering a selected wavelength band of light from a DWDM input light. Each grating unit includes a respective tunable optical element, which have a reflective element, such as a Bragg grating. Generally, one grating unit filters a selected wavelength band of light and reflects the selected wavelength band to the other grating unit, which reflects a portion of the reflected wavelength band to an output of the optical filter. This double reflection of the selected wavelength band provides an optical filter having an effective filter function that is equal to the product of the individual filter functions of the grating units. To create a desired effective filter function, the gratings may be written to have different filter functions or grating profiles.

Abstract: An apparatus is presented for damping an undesired component of an ultrasonic signal. The apparatus includes a sensor affixed to a pipe. The sensor includes a transmitter and a receiver. The transmitted ultrasonic signal includes a structural component propagating through the pipe and a fluid component propagating through a flow in the pipe. The receiver receives one of the transmitted components. The apparatus includes a damping structure. The damping structure dampens the structural component of the ultrasonic signal to impede propagation of the structural component to the receiver. The damping structure includes one of a housing secured to the pipe to modify ultrasonic vibrational characteristics thereof, a plurality of film assemblies including a tunable circuit to attenuate structural vibration of the pipe, and a plurality of blocks affixed to the pipe to either reflect or propagates through the blocks, the undesired structural component of the ultrasonic signal.

Abstract: A method for sensing flow within a pipe having an internal passage disposed between a first wall portion and a second wall portion is provided, comprising the steps of: 1) providing a flow meter having at least one ultrasonic sensor unit that includes an ultrasonic transmitter attached to the first wall portion and an ultrasonic receiver attached to the second wall portion and aligned to receive ultrasonic signals transmitted from the transmitter; 2) selectively operating the ultrasonic transmitter to transmit a beam of ultrasonic signal, which beam has a focal point such that within the pipe, the beam is either colliminated, divergent or convergent; and 3) receiving the ultrasonic signals within the beam using the ultrasonic receiver. An apparatus operable to perform the aforesaid method is also provided.

Abstract: A method and apparatus for measuring a parameter of a flow passing through a pipe is provided, wherein the apparatus includes at least two spatial array of sensors disposed at different axial locations along the pipe, wherein each of the sensors provide a signal indicative of unsteady pressure created by coherent structures convecting with the flow within the pipe at a corresponding axial location of the pipe. The apparatus also includes a signal processor configured to determine the flow rate at the circumference location of each sensor array in response to the respective measured unsteady pressures. The signal processor compares the velocity of the flow at each respective location and provides a signal indicative the presence of solids settled at the bottom of the pipe and/or the level of the settled solids in the pipe, in response to an uncharacteristic increase in the velocity of a lower portion of the flow in comparison to the velocity measured above the lower portion of the flow.

Abstract: An apparatus for measuring at least one parameter associated with a fluid flowing within a pipe includes a spatial array of pressure sensors disposed at different axial locations x1. . . xN along the pipe. Each of the pressure sensors provides a pressure signal P(t) indicative of unsteady pressure within the pipe at a corresponding axial location of the pipe. A signal processor receives the pressure signals from each of the pressure sensors and determines the parameter of the fluid using pressure signals from selected ones of the pressure sensors. By selecting different pressure sensors, the signal processor can configure the array to meet different criteria. In one embodiment, the array of pressure sensors may be formed on a single sheet of polyvinylidene fluoride (PVDF) that is wrapped around at least a portion of an outer surface of the pipe. This arrangement allows a large number of pressure sensors to be quickly and economically installed.

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 tunable optical filter has a large diameter cane waveguide with “side-holes” in the cane cross-section that reduce the force required to compress the large diameter optical waveguide without overly compromising the buckling strength thereof. The large diameter optical waveguide has a cross-section of at least about 0.3 millimeters, including at least one inner core, a Bragg grating arranged therein, a cladding surrounding the inner core, and a structural configuration for providing a reduced bulk modulus of compressibility and maintaining the anti-buckling strength of the large diameter optical waveguide. The structural configuration reduces the cross-sectional area of the large diameter optical waveguide. These side holes reduce the amount of glass that needs to be compressed, but retains the large diameter.

Abstract: A fluid diffusion resistant tube-encased fiber grating pressure sensor includes an optical fiber 10 having a Bragg grating 12 impressed therein which is encased within a sensing element, such as a glass capillary shell 20. A fluid blocking coating 30 is disposed on the outside surface of the capillary shell to prevent the diffusion of fluids, such as water molecules from diffusing into the shell. The fluid diffusion resistant fiber optic sensor reduces errors caused by the diffusion of water into the shell when the sensor is exposed to harsh conditions.

Abstract: A large diameter D-shaped optical waveguide device 9, includes an optional circular waveguide portion 11 and a D-shaped waveguide portion 10 having at least one core 12 surrounded by a cladding 14. A portion of the waveguide device 9 has a generally D-shaped cross-section and has transverse waveguide dimension d2 greater than about 0.3 mm. At least one Bragg grating 16 may be impressed in the waveguide 10 and/or more than one grating or pair of gratings may be used and more than one core may be used. The device 9 provides a sturdy waveguide platform for coupling light into and out of waveguides and for attachment and alignment to other waveguides, for single and multi-core applications. The core and/or cladding 12,14 may be doped with a rare-earth dopant and/or may be photosensitive. At least a portion of the core 12 may be doped between a pair of gratings 50,52 to form a fiber laser or the grating 16 or may be constructed as a tunable DFB fiber laser or an interactive fiber laser within the waveguide 10.

Abstract: A large diameter optical waveguide, grating, and laser includes a waveguide 10 having at least one core 12 surrounded by a cladding 14, the core propagating light in substantially a few transverse spatial modes; and having an outer waveguide dimension d2 of said waveguide being greater than about 0.3 mm. At least one Bragg grating 16 may be impressed in the waveguide 10. The waveguide 10 may be axially compressed which causes the length L of the waveguide 10 to decrease without buckling. The waveguide 10 may be used for any application where a waveguide needs to be compression tuned, e.g., compression-tuned fiber gratings and lasers or other applications. Also, the waveguide 10 exhibits lower mode coupling from the core 12 to the cladding 14 and allows for higher optical power to be used when writing gratings 16 without damaging the waveguide 10. The shape of the waveguide 10 may have other geometries (e.g.

Abstract: A fluid diffusion resistant tube-encased fiber grating pressure sensor includes an optical fiber 10 having a Bragg grating 12 impressed therein which is encased within a sensing element, such as a glass capillary shell 20. A fluid blocking coating 30 is disposed on the outside surface of the capillary shell to prevent the diffusion of fluids, such as water molecules from diffusing into the shell. The fluid diffusion resistant fiber optic sensor reduces errors caused by the diffusion of water into the shell when the sensor is exposed to harsh conditions.

Abstract: A strain-isolated bragg grating temperature sensor includes an optical sensing element 20,600 which includes an optical fiber 10 having at least one Bragg grating 12 disposed therein which is encased within and fused to at least a portion of a glass capillary tube 20 and/or a large diameter waveguide grating 600 having a core and a wide cladding and having the grating 12 disposed therein, which senses temperature changes but is substantially not sensitive to strains on the element caused by the fiber or other effects. Light 14 is incident on the grating 12 and light 16 is reflected at a reflection wavelength ?1. The shape of the sensing element 20,600 may be other geometries and/or more than one concentric tube may be used or more than one grating or pair of gratings may be used or more than one fiber or optical core may be used.