A pressure sensor and a method of measuring pressure with the pressure sensor, based on measuring the effect of pressure loads on the acoustic resonance mode frequencies of a spherical core (e.g., a hollow sphere). The pressure sensor includes a transmitter configured to transmit vibrational signals to a sphere, and a receiver on the opposite side of the spherical core that is configured to receive vibrational signals from the spherical core. According to the method of measuring pressure with this sensor, the spherical core exhibits a pressure-dependent resonance response that can be monitored utilizing a frequency response technique. Peak shifts observed under an unknown pressure load can be compared to a calibration of the spherical core under a series of known pressure loads to thereby determine the unknown pressure. The pressure sensor and method may be operated in real-time at very high temperatures and pressure, and may be used in borehole applications and in aggressive media.

A sensing method is based on using a special fiberoptic probe for detection of acoustic/ultrasound pressure in an immersion medium. The developed system is highly sensitive in detecting ultrasound waves up to 100 MHz, for imaging of micro structures and more. For applications up to 100 MHz, without spatial averaging corrections, the probe tip is modified by reducing the fiber diameter to 7 um or less. Also, to maximize acousto-optic interaction, the probe tip, not just its end face, may be coated with a thin layer of metallic material. This thin film coating satisfies partial transparency of the metallic coating. The coating thickness may range from 2 nm to 10 nm or others depending on the type of the coating material. The probe detects the pressure of acoustic and/or ultrasound waves propagating within an immersion medium, whenever the probe tip is immersed inside the medium, and having a reasonable immersion contact surface.

A sensing method is based on using a special fiberoptic probe for detection of acoustic/ultrasound pressure in an immersion medium. The developed system is highly sensitive in detecting ultrasound waves up to 100 MHz, for imaging of micro structures and more. For applications up to 100 MHz, without spatial averaging corrections, the probe tip is modified by reducing the fiber diameter to 7 um or less. Also, to maximize acousto-optic interaction, the probe tip, not just its end face, may be coated with a thin layer of metallic material. This thin film coating satisfies partial transparency of the metallic coating. The coating thickness may range from 2 nm to 10 nm or others depending on the type of the coating material. The probe detects the pressure of acoustic and/or ultrasound waves propagating within an immersion medium, whenever the probe tip is immersed inside the medium, and having a reasonable immersion contact surface.

An apparatus and method for measuring the internal pressure of a pipe or container is disclosed. The apparatus includes an acoustical transmitter (Tx.sub.1) mounted on a wall (1) of said pipe or container and a signal generator (2) connected to said transmitter and which is adapted to provide a signal to the transmitter. The signal from the transmitter is detected by two receivers (Rx.sub.1, Rx2) mounted on said pipe or container in a distance from said transmitter (Tx.sub.1). A processing unit (3) is connected to said transmitter and receivers, the processing unit being adapted to measure the travel time of an acoustical signal propagating between two receivers in the wall (i) and determine the pressure inside the pipe or container from said travel time.

An apparatus and method for measuring the internal pressure of a pipe or container is disclosed. The apparatus includes an acoustical transmitter (Tx.sub.1) mounted on a wall (1) of said pipe or container and a signal generator (2) connected to said transmitter and which is adapted to provide a signal to the transmitter. The signal from the transmitter is detected by two receivers (Rx.sub.1, Rx2) mounted on said pipe or container in a distance from said transmitter (Tx.sub.1). A processing unit (3) is connected to said transmitter and receivers, the processing unit being adapted to measure the travel time of an acoustical signal propagating between two receivers in the wall (i) and determine the pressure inside the pipe or container from said travel time.

Disclosed herein is a carbonated water producing apparatus which guides a replacement of a cylinder using sound generated when carbon dioxide is supplied from the cylinder, and a refrigerator having the same. In accordance with one aspect of the present disclosure, a carbonated water producing apparatus comprising: a carbonated water producing unit including a cylinder configured to store carbon dioxide and configured to supply the carbon dioxide to a container; a microphone configured to obtain sound generated in the carbonated water producing unit; a filter configured to pass a signal having a frequency of a predetermined cutoff frequency or more of signals obtained by the microphone; a user interface unit configured to display information related to carbonated water production; and a controller configured to obtain the sound generated in the carbonated water producing unit by driving the microphone when the carbonated water producing unit operates, and configured to display a message which requests that the cylinder which stores the carbon dioxide be replaced on the user interface unit when an intensity of a signal passing through the filter is less than a predetermined reference value.

The invention relates to a segment of pipe-in-pipe pipeline comprising an annulus under reduced pressure sealed and delimited by a metallic internal pipe inserted into a metallic external pipe and provided with a measurement system to determine in a non-intrusive manner the state of the annulus, the measurement system being composed of a first internal emitter/receiver assembly placed inside the annulus and cooperating with means to measure a first physical quantity such as pressure, hygrometry or temperature inside the reduced pressure annulus and a second external emitter/receiver assembly arranged to the exterior of the segment and facing said first assembly.

The invention relates to a segment of pipe-in-pipe pipeline comprising an annulus under reduced pressure sealed and delimited by a metallic internal pipe inserted into a metallic external pipe and provided with a measurement system to determine in a non-intrusive manner the state of the annulus, the measurement system being composed of a first internal emitter/receiver assembly placed inside the annulus and cooperating with means to measure a first physical quantity such as pressure, hygrometry or temperature inside the reduced pressure annulus and a second external emitter/receiver assembly arranged to the exterior of the segment and facing said first assembly.

Downhole distributed pressure sensor arrays include sensor housings each comprising at least one pressure sensor in a pressure housing. Downhole pressure sensors include a housing, at least one pressure sensor in a pressure housing portion of the housing, and at least one isolation element positioned at an outer wall of the housing.

A cylindrical quartz crystal transducer that exhibits a low probability of twinning, and uses a combination of resonator signal inputs at the B-mode and C-mode frequencies to calculate resonator temperature. Crystallographic orientations are disclosed where combinations of B-mode and C-mode resonant frequencies exist that are sufficiently independent of pressure to enable accurate calculation of temperature under transient conditions. Such a transducer is usable at higher pressures and temperatures than conventional quartz pressure transducers. Furthermore, because the structure allows a choice of crystallographic orientation, other characteristics of the transducer, such as increased pressure sensitivity and activity dip-free operation, may be optimized by varying crystallographic orientation.