Abstract: Embodiments include a consumable medical device comprises a rigid cartridge to which a film is adhered to form a fluid channel and a damper chamber. A portion of the film forming the damper chamber has a wave-like shape adapted to roll onto a tip of a damper. The damper has a plunger to minimize peristaltic pressure in the channel. The cartridge may include conductivity measurement channels. Crosstalk may be minimized by using different frequencies or time division for reading the channels. A stable dialysate concentrate containing sodium lactate may be used or generated with the system. The concentrate may be formed to higher concentration than feasible with a single component concentrate by forming two containers of concentrate, each containing a fraction of a total quantity of sodium lactate required for a predefined number of dialysis.

Abstract: A device forming a manometer, configured to measure pressure of a biphasic fluid in a fluidic network, including: a first channel inside which a biphasic fluid is able to flow; a second channel emerging into the first channel, wherein the second channel is blind, with each of its dimensions less than capillary length of the fluid's liquid phase, and with at least one of its lengthways wall having a surface energy gradient that decreases from its inlet to the end. The surface energy gradient enables the wetting angle of the meniscus of the fluid's liquid phase to be increased in the blind channel from its inlet to the end. Such a device may find application to measurement of pressure of a biphasic fluid in a heat exchanger or in a fuel cell.

Abstract: A device forming a pressure sensor is provided. The device includes: a substrate made of electrical insulation material including a first reservoir, a second reservoir in communication with the first reservoir and of which two internal walls are each equipped with an electrode, and a flexible membrane made of an electrical insulation material, including a protuberance and secured to the substrate so as to enable movement of the protuberance between a position in which it is at a distance from a liquid filling the first reservoir and at least one second position in which it exerts a pressure on the liquid, thus discharging it at least partially from the first reservoir toward the second reservoir with mechanical contact with the two electrodes, the mechanical contact of the liquid with the electrodes establishing a resistance or capacitance between the electrodes. Application in the production of a touch screen is also provided.

Abstract: A sound sensor, a hydrophone including the sound sensor, and a pressure balancing device for using for the hydrophone are provided. The hydrophone includes: a sensor including a sensing part and a pressure balancing part; a printed circuit board (PCB) that is electrically connected to the sensor; a case that houses the sensor and the PCB and that has an opening at one side thereof; an elastic membrane that covers the opening of the case; and a signal line that is electrically connected to the PCB to be extended to the outside of the case. The pressure balancing part includes a diaphragm of a thin film and a support that supports the diaphragm. A pressure balancing hole is formed at one side of the pressure balancing part, and at the inside of the pressure balancing part, a channel that is connected to the pressure balancing hole is formed, and a compressible gas is filled in the channel.

Abstract: A pressure detection device for use in an electronic manometer includes a container for receiving a liquid, a first conduit for the air to pass through, and a second conduit for the liquid to flow therein. When the air having the same pressure as that of a pressure transducer is directly or indirectly drawn from the electronic manometer through the first conduit into the container, the liquid in the container flows into the second conduit due to the pressure difference. In this way, get a difference between the liquid level of the second conduit and that of the container and compare the difference with a user's blood pressure measured by the electronic manometer to detect whether the measuring result of the electronic manometer is accurate or not.

Abstract: The invention provides a method for controlling an electronic manometer for measuring pressure (p) inside a pressurized gas receptacle. The manometer comprises at least one pressure sensor, an electronic unit designed for the acquisition, storage and processing of data, and at least one information device device capable of transmitting at least one item of information (p).

Abstract: The invention relates to a method for controlling an electronic pressure gauge for measuring the pressure (P) inside a pressurised gas container, particularly a pressurised gas cylinder, said pressure gauge (1) including: at least one pressure sensor (14); an electronic unit (44) designed to acquire, store and process data; and at least one information device (34) capable of transmitting at least one item of information (P).

Abstract: A force sensor assembly includes a force sensor, a first support member, a threaded portion, an opening made in the first support member, a nut, a restricting member and a spacer. The nut is screwed onto the threaded portion which is inserted through the opening. The restricting member is provided between the force sensor and the nut. The spacer, which is provided between the force sensor and the nut, is deformable in a direction of its thickness. The shape of the spacer is adapted to avoid interference with the restricting member. Before the nut is tightened onto the threaded portion, a summation of thickness for the first support member and the spacer is adapted to be not less than a height of the restricting member. The nut is tightened up with a predetermined fastening torque until the spacer deforms so that the nut strikes the restricting member.

Abstract: A system and method of managing fuel vapor pressure in a fuel system. The direction of air flow between first and second ports on either side of a chamber is controlled by a liquid that divides the chamber into first and second portions. A leak detection test, excess vacuum venting, and pressure blow-off of the fuel system are controlled by displacement of the liquid.

Abstract: A pressure measurement device comprising a housing enclosing an elastic pressure measurement element and a magnet attached to the measurement element. First and second Hall sensors operatively positioned near the magnet are connected to an electrical circuit which processes the sensor outputs to provide first and second output signals. The positions of the Hall sensors can preferably each be adjusted from outside the housing.

Abstract: A pressure sensor is mounted upon a hydraulic valve body. The sensor has a base which extends into a bore formed in the valve body. The valve body bore is in communication with a pressurized hydraulic fluid. A cover that is removably attached to the valve body encloses the pressure sensor. A circuit substrate is disposed within the cover and electrically connected to the pressure sensor.

Abstract: A method and device for void fraction measurement in a gas/liquid two-phase stratified flow system in disclosed. A couple of pressure-signal tubes are mounted to the through into the top and bottom walls of the horizontal pipeline portion of the flow system to measure the pressure differential value between the top and bottom interior position thereof. The height of liquid phase level of the stratified flow is calculated from the pressure differential value and the liquid-phase density. The void fraction is derived from the known geometric relation between the height of liquid-phase level and the cross section of the pipe. Each of the pressure-signal tubes is encased within a cylindrical cooling case to avoid flashing phenomenon from occurring within the pressure-signal tube. This method is applicable for the flow at steady or transient state under high temperature/pressure condition.

Abstract: A beam is mounted to a mounting flange. A seat pan is mounted to opposite end portions of the beam. Provided near a middle portion of the beam is a sensor unit for detecting flexure of the middle portion of the beam. The sensor unit has a sensor beam whose length is sufficiently less than the distance between fulcrums of the beam, and a transmission member that transmits the flexure of the beam occurring at a middle point thereof to the sensor beam. The sensor beam is provided with a strain sensor.

Abstract: When a suction/breakdown instruction signal is changed over from a high state to a low state, a vacuum generating electro-magnetic valve is turned on (the vacuum release electro-magnetic valve is closed). If the negative pressure in the pressure tube is equal to or greater than a determining value, suction breakdown confirmation output is turned on. When the delay time has lapsed from this time, the vacuum generating electro-magnetic valve is turned off. When the pressure in the pressure tube is smaller by a predetermined value than the suction determining value, the output of the suction breakdown confirmation is turned off. When the delay time has lapsed since the change-over time from the low state to the high state, the vacuum release electro-magnetic valve is turned on. When the positive pressure in the pressure tube is equal to or greater than the breakdown determining value, the output of the suction breakdown confirmation is set to the high state.

Abstract: A pressure sensor system includes a first conductive surface electrically isolated from a second conductive surface. A dielectric material is interposed between the first conductive surface and the second conductive surface. The dielectric material is movable with respect to at least one of the first conductive surface and the second conductive surface in response to a change in pressure exerted on the pressure sensor. A measurement system is connected to at least one of the first conductive surface and the second conductive surface to measure the capacitance between the first conductive surface and the second conductive surface representative of pressure.

Abstract: An apparatus for measuring the differential pressure between at least two fluids including (a) first and second pressure enclosures; (b) first and second pressure deformable members where the first deformable member is sealingly connected to the first pressure enclosure and second deformable member is sealingly connected to the second pressure enclosure and the pressure deformable members are rigidly linked so as to move as one unit; (c) a frame for locating the first and second pressure enclosures in fixed relationship to one another; (d) a position sensing device for determining the displacement of the pressure deformable members relative to the frame; (e) a force balancing device including a first portion rigidly connected to the frame and a moveable second portion connected to the pressure deformable members; and (f) a transducer for transducing the displacement of the first and second pressure deformable members into a force acting on the moveable second portion of the force balancing device in a directi

Abstract: A vacuum controlling apparatus is provided. The vacuum level of a vacuum chamber can be accurately maintained by measuring and controlling the vacuum level of the vacuum chamber by using six parameters: desired pressure, predetermined time for reaching the desired pressure, predetermined temperature, actual pressure, actual time for reaching the desired pressure, and actual temperature.

Abstract: A liquid level monitoring system, which monitors the level of liquid in a storage tank, includes a differential pressure sensor that uses a magnetic fluid, or ferrofluid, sensing element. The pressure sensor is U-shaped with a first one leg connected, via a first pressure chamber, to a bubbler tube that extends downwardly into the storage tank. The second leg of the U-shaped sensor connects to a second pressure chamber, which applies to the second leg a selected, fixed pressure. The pressure applied to the first leg of the sensor is proportional to the hydrostatic back pressure in the bubbler tube, which varies directly with the level of liquid in the storage tank. Wound around the legs of the pressure sensor are inductance coils. The inductances of these coils change as the ferrofluid sensing element moves within the sensor. Accordingly, the inductances change as the level of liquid in the storage tank varies.

Abstract: A pressure sensor having a tubular member partially filled with a ferrofluid column and partially filled with air, with an electrically conductive coil wrapped around the tubular member. When in use, the coil has alternating current running therethrough and the voltage across the coil is monitored. Physiologic pressure variations result in proportional variations in the position of the ferrofluid/air interface relative to the coil. This results in proportional changes in the coil voltage due to the change in coil inductance. The pressure sensor is compact and can be incorporated into many devices including a guide wire.

Abstract: A differential pressure sensor includes a ferrofluid sensing element, or slug, that changes position in a tapered magnetic field in response to a pressure differential. The ferrofluid slug is contained in a tube and moves within the tapered magnetic field, which is perpendicular to the longitudinal axis of the tube. The field has a maximum flux density at its center and tapers off in both axial directions from its center. In response to a pressure differential of zero, the slug is centered in the field. In response to a non-zero pressure differential, the slug moves to the position in the field where the net magnetic forces equal the pressure differential. The position of the slug is sensed by sensing elements which produce output signals that vary according to the position of the slug.

Abstract: A method of obtaining electrical signals corresponding to the position of a mercury mass movable within a vessel, characterized by the fact that the position of the moving mass within the vessel is detected by means of at least one electromagnetic proximity sensor, specifically an induction proximity sensor, that is a sensor adapted to producing an electrical signal when approached by a metal object or when approaching the same.

Abstract: An electronic manometer for measuring pressure differentials between first and second outlets of a U tube supporting a column of mercury. The U tube includes for each arm a coaxial feedline which is terminated by the column of mercury. The coaxial feedlines are connected to first and second oscillators where they serve as the frequency determining circuit element of the oscillators. The wavelength of each oscillator frequency of oscillation is directly proportional to the height of the mercury column. A frequency counter and computer are connected to measure this wavelength, and apply any necessary corrective factors to the measurement.

Abstract: A method of obtaining electrical signals corresponding to the position of a mercury mass movable within a vessel, characterized by the fact that the position of the moving mass within the vessel is detected by means of at least one electromagnetic proximity sensor, specifically an induction proximity sensor, that is a sensor adapted to producing an electrical signal when approached by a metal object or when approaching the same.

Abstract: A vacuum pressure monitoring system includes a mercury manometer in communication with a vacuum line from an apparatus operating under high vacuum (approx. 0.25 in. Hg). A proximity sensor targets the height of the Hg. Incremental changes in the height of the Hg are detectable by the proximity sensor which triggers safety control components for alerting personnel and for protecting the apparatus.

Abstract: A bi-axial compression test apparatus for geomaterial (soil, etc.) samples that is designed to allow free shear band formation and provide measurements of the stress displacement characteristics of the failure zone. A geomaterial sample formed into a specimen comprising a right rectangular prism is surrounded by a thin rubber membrane and is supported by walls along two parallel faces. An axial load is kinematically applied by a plate that is guided to prevent any tilt or eccentricity, while a bottom support plate for the specimen is horizontally guided by a linear bearing that is substantially friction free. All of the surfaces in contact with the specimen are glass lined and lubricated to minimize friction. The assembly of the specimen and its supports is placed in a conventional tri-axial cell in a loading frame so that an axial load can be applied to one end of the specimen and reacted against the bottom plate.

Abstract: This invention relates to mercury manometers for a purge bubbler liquid level control system or the like. More particularly, this invention relates to mercury manometers comprising a mercury column with electrical contacts imbedded in the walls of the column for sensing specific liquid levels.

Abstract: A U-tube manometer for calibrating a differential pressure transducer or the like, wherein the height of working fluid in each column may be determined by the two-way travel time of an acoustic pulse launched from the top of each column against the top of the working fluid. The propagation velocity of each acoustic pulse is determined by a calibration target integral with each tube and located above the working fluid at a predetermined distance from each acoustic source. The generation and detection of each acoustic pulse is monitored by a remote processor and recorder which calculates the pressure differential between the two tubes of the manometer.

Abstract: A prebubble detector is provided for an underwater drainage apparatus. A series of sensors and detectors are disposed along the small arm of the underwater seal in a drainage device and means is provided for detecting the least degree of negativity reached during each breathing cycle. This information is fed to a logic circuit, timer and display so that the physician can readily see what the least degree of negativity reached is and how long a period of time has elapsed since the least degree of negativity has not decreased. A continuing trend of the least degree of negativity toward zero would indicate an air leak in the pleural cavity whereas stability of the least degree of negativity would indicate no air leak in the pleural cavity.

Abstract: The respirometer module consists of an airtight chamber which includes an air pump, a carbon dioxide scrubber, an electronic gas volume transducer, an air vent, and a fill tube. This single module is combined with separate sample chambers of various sizes and applications. The sample chambers are designed for laboratory, on-line, or submersible application to measure respiration of microorganisms, animals, fish, and plants. The respirometer module which provides air circulation, CO.sub.2 absorption, and electronic gas volume sensing can be used interchangeably with any one of these specialized chambers.

Abstract: A method of obtaining electrical signals corresponding to the position of a mercury mass movable within a vessel, characterized by the fact that the position of the moving mass within the vessel is detected by means of at least one electromagnetic proximity sensor, specifically an induction proximity sensor, that is a sensor adapted to producing an electrical signal when approached by a metal object or when approaching the same.

Abstract: A pressure transducer of the manometer type comprises two interconnected columns of liquid with means for applying differential pressure across the columns. The liquid is a magnetic liquid and a magnetic field is impressed on the columns to attract the liquid by magnetic force to a reference position. The applied differential pressure acts counter to the magnetic force to shift the columns so that their difference in lengths reflects the pressure. By using capacitor plates to define the walls for the liquid columns and a magnetic liquid which is a dielectric, the capacitance between the plates is a function of the column lengths and therefore is a function of the applied differential pressure.

Abstract: A manometer is provided for metering samples of fluid flowing in devices wherein particle concentration in the fluid is being counted or measured. Such devices include particle counters for determining blood cell concentration in body fluid. The device includes low permeable stretchable diaphragms in the device connections for containing the mercury therein, and a slide valve in the vent connection to restrict the movement of the mercury during storage or shipment. The arrangement herein includes, also, a one-way valve downstream of the "stop" point to stop flow substantially immediately upon the cessation of the measurement interval to reduce unwanted airflow to the counting aperture. A start and stop arrangement in the mercury flow path for causing the leading edge of the mercury meniscus at the axis thereof to engage the electrode contacts includes simple wire tips extending into the mercury flow path to the axis thereof for engaging the axis of the mercury meniscus.

Abstract: A manometric method and instrument for the continuous detection and measurement of differential pressures which includes a uniquely configured multi-capacitor sensor system. The sensor system is formed of a first pair of plate type capacitors having like dielectric spaces within which a first strata of fluids is maintained and subjected to one pressure force and a second pair of plate type capacitors having like dielectric spaces within which a second strata of fluids is maintained and subjected to another pressure force. The dielectric spaces of each pair of capacitors are interconnected at their lower ends so that the pairs of dielectric spaces form the legs of a classic U-tube manometer whereby the first strata of fluids and the second strata of fluids assume equilibrium positions within their respective dielectric spaces in relation to the densities of such fluids and the respective applied pressure forces.

Abstract: A transducer for providing an output signal having a value determined by an input pressure differential includes a capacitance manometer having a first input for receiving a first input pressure and a second input for receiving a second input pressure, the capacitance manometer having a capacitance determined by the difference between the first and second input pressures, and an output circuit connected to the capacitance manometer for providing an output signal having a value dependent upon the capacitance.

Abstract: A flat plate manometer includes a rectangular mercury column having calibration scales and a plurality of closely spaced stainless steel contacts disposed along the column. The mercury closes a circuit between a common contact and the column contacts as the mercury rises. The manometer is fabricated from acrylic plastic to provide a lightweight, low cost device. The input and output ports include microporous filters to prevent accidental loss of mercury.

Abstract: Disclosed is a method and apparatus for measuring and/or continuously recording small pressure differences by means of a novel manometer-like device. Accuracies of plus or minus about 0.05 dynes/square centimeter are achieved by means of a disclosed device which can measure, record, and self-calibrate.

Abstract: An electric pressure switch for use with textile machines and the like has a U-shaped tube filled with a liquid. One of the legs is above the liquid level in communication with a source of variable fluid pressure, for example a fiber feeding chute of a textile machine and this same leg, with the other leg, is provided with two or more vertically spaced detecting arrangements which detect changes in the position of the liquid level which occur as the fluid pressure fluctuates, and such detections are converted into electrical signals which can control various functions, such as the drive for fiber feeding devices or the like.

Abstract: Liquid level in tanks is gauged an can be controlled as follows. Liquid communication is provided from near the bottom of the tank to a liquid reservoir containing a liquid which is of different density and immiscible with the tank liquid. The reservoir is in liquid communication with a vertically elongated vessel having a relatively small horizontal area compared to the tank, communication being near the top of the reservoir if the reservoir liquid is less dense than the tank liquid and being near the bottom of the reservoir if the reservoir liquid is more dense than the tank liquid. The elongated vessel, which can be transparent or translucent so that the liquid level therein corresponding to the liquid level in the tank can be readily determined, can contain a float containing a proximity sensor triggering element.

Abstract: An overpressure device is disclosed for use in a liquid infusion set for the purpose of detecting excessive pressures which may occur during infusion. The device comprises a tubular member with an inlet and an outlet, a closed pressure chamber and a bridging portion containing a small bore passage which connects the pressure chamber with the tubular member. In a preferred form, the interconnecting passage takes a tortuous path. An optical sensor positioned on the pressure chamber will detect the presence of liquid at a predetermined position in the chamber, when the liquid rises as a result of excessive pressure in the set, and respond by stopping the flow of liquid in the set.