9246 results about "Differential pressure" patented technology

A gas delivery system accurately measures and optionally regulates mass flow rate in real time. A fluid conduit connects an inlet valve, calibration volume, flow restrictor, and outlet valve in series. Pressure and temperature sensors are coupled to the calibration volume. One or more pressure sensors may be attached across the flow restrictor. Alternatively, an absolute pressure sensor may be attached upstream of the flow restrictor. One embodiment of differential pressure sensors comprises a floating reference differential pressure sensor, including a first transducer attached to the fluid conduit upstream of the flow restrictor and a second transducer attached to the conduit downstream of the flow restrictor. In this embodiment, each transducer receives a reference pressure from a reference source, and optionally, after the calibration volume is charged, the floating reference differential pressure transducers are calibrated. When gas flow is initiated, differential and/or absolute pressure measurements are repeatedly taken, and a measured mass flow rate calculated thereon. Gas flow is adjusted until the measured mass flow rate reaches a target mass flow. Using the temperature/pressure sensors at the calibration volume, repeated calculations of actual flow rate are made to uncover any discrepancy between actual and measured mass flow rates. Whenever a discrepancy is found, the manner of calculating measured mass flow is conditioned to account for the discrepancy; thus, the measured mass flow rate more accurately represents the actual mass flow rate thereby providing an actual mass flow rate more accurately achieving the target mass flow rate.

A vacuum chamber is evacuated through a first evacuation passage provided with a first valve and a second evacuation passage provided with a second valve. An opening degree of the first valve is adjusted so that a pressure in the vacuum chamber becomes substantially equal to a process pressure P; an opening degree of a butterfly valve further provided in the second evacuation passage is adjusted to substantially equal to a set value determined by a table in order to set flow rates of gases to be evacuated through the first evacuation passage and the second evacuation passage to be substantially equal to corresponding set values determined by the recipe; and an opening degree of the second valve is adjusted so that a measurement value of a differential pressure gauge further provided in the second evacuation passage becomes substantially equal to a differential pressure written in the table.

Methods, systems, and products for monitoring an air filter. Methods involve determining a difference between a baseline pressure differential and a current pressure differential, the differential pressure between pressure at an upstream side of the filter and pressure at a downstream side of the filter. The baseline pressure differential may be set automatically or by a user. Reaching or exceeding a predetermined threshold triggers an indication of a clogged condition. The method also includes monitoring the air filter condition intermittently. The filter monitor may operate for extended periods in a sleep state and intermittently power up to a wake state to measure the current pressure differential and compare the current pressure differential with a baseline pressure differential.

An automated fluid delivery system and method are disclosed. The system includes distensible tubing, a flow controller, and a fluid flow adjustment module. The fluid flow adjustment module may be configured to detect differential pressure in the tubing and adjust the flow controller to provide an amount of fluid through the tubing during inhalation.

A wireless sensor unit detects an out-of-range condition of an air filter in a HVAC system by sensing the air flow passing across the filter or by pressure differential across the air filter. A The sensor unit sends a signal to a receiver unit that can be positioned a distance from the sensor unit to process the signal sent by the sensor unit and provide audio and/or visual warning of the air filter condition.

A real-time monitoring system that monitors various aspects of the operation of a refrigerant-cycle system is described. In one embodiment, the system includes a processor that measures power provided to the refrigerant-cycle system and that gathers data from one or more sensors and uses the sensor data to calculate a figure of merit related to the efficiency of the system. In one embodiment, the sensors include one or more of the following sensors: a suction line temperature sensor, a suction line pressure sensor, a suction line flow sensor, a hot gas line temperature sensor, a hot gas line pressure sensor, a hot gas line flow sensor, a liquid line temperature sensor, a liquid line pressure sensor, a liquid line flow sensor. In one embodiment, the sensors include one or more of an evaporator air temperature input sensor, an evaporator air temperature output sensor, an evaporator air flow sensor, an evaporator air humidity sensor, and a differential pressure sensor. In one embodiment, the sensors include one or more of a condenser air temperature input sensor, a condenser air temperature output sensor, and a condenser air flow sensor, an evaporator air humidity sensor. In one embodiment, the sensors include one or more of an ambient air sensor and an ambient humidity sensor.

A method of treating a tissue site is provided. The method includes applying a reduced pressure to a tissue site with a reduced pressure source. A source pressure is monitored at the reduced pressure source, and a differential pressure is determined between the source pressure and the desired tissue site pressure. If a blockage is present between the reduced pressure source and the tissue site, the differential pressure is limited to a first maximum differential pressure. If no blockage is present between the reduced pressure source and the tissue site, the differential pressure is limited to a second maximum differential pressure.

A downhole tool is disclosed that functions as an underreamer, or alternatively, as a stabilizer in an underreamed borehole. An embodiment of the tool includes one or more moveable arms disposed within a body having a flowbore therethrough in fluid communication with the wellbore annulus. The tool alternates between collapsed and expanded positions in response to differential fluid pressure between the flowbore and the wellbore annulus. In one embodiment, the tool moves automatically in response to differential pressure. In a second embodiment, the tool must be selectively actuated before it is moveable. When the tool expands, the arms are preferably translated axially upwardly, while simultaneously being extended radially outwardly from the body. The expanded tool diameter is adjustable at the surface without changing components. The arms may include borehole engaging pads that comprise cutting structures or wear structures or both, depending upon the function of the tool.

An implantable, refillable, rate controlled drug delivery device is disclosed that includes a base structure having at least a first opening and a second opening, the base structure defining a chamber, a septum covering the first opening and configured to substantially prevent leakage from the first opening to an exterior of the device, a drug delivery tube comprising a first and second distal end, wherein the first distal end of the tube communicates with the chamber through the second opening, and at least one rate-limiting permeable membrane disposed across a passage between the base structure and the second distal end of the drug delivery tube, which membrane passively regulates drug delivery. The drug delivery device is used to provide controlled drug delivery to an internal portion of the body and is advantageously leak-proof and does not rely on a pressure differential to drive the drug from the device.

Several methods of controlling a vacuum cleaner (10) using various types of sensors (94, 96, 97, 98) are provided. One method is based on a differential pressure between a suction airflow path and ambient air and includes: detecting the differential pressure, comparing the detected differential pressure to a predetermined threshold, and, when the detected differential pressure is less than the predetermined threshold, initiating a predetermined control procedure. A status indicator (164) is updated based on the detected differential pressure. Another method is based on a level of electrical current flowing through a brush motor (100). Still another method is based on a type or condition of the floor being traversed. Yet another method is based on a distance to a surface of a floor over which the vacuum cleaner is advancing. In another aspect of the invention, a vacuum cleaner is provided. In various combinations, the vacuum cleaner includes a vacuum source (36, 38), a brush motor (100), a drive motor (104), a controller processor (74), a sensor processor (90), an overcurrent sensor (98), a suction airflow sensor (94), a floor type sensor (97), and a floor distance sensor (96).

A catheter with valve for implantation in a vascular structure of a living being. The catheter is in the general shape of a "T" with the top of the "T" implanted within the lumen of a vascular structure, and the leg of the "T" extending out of the vascular structure through an incision in the vascular structure. The lumen of the implanted portion of the catheter completely occupies the lumen of the vascular structure, causing all blood flow through the vascular structure to be directed through the implanted portion of the catheter. A valve is placed in the wall of the implanted portion of the catheter which opens into the lumen of the leg of the "T" of the catheter upon application of sufficient differential pressure between the lumens of the two portions of the catheter. The leg of the "T" is connected to the side wall of the implant portion of the catheter at an angle, such that the axis of the lumen of the leg of the "T" intersects the axis of the lumen of the implanted portion of the catheter at approximately a 45 degree angle.

The invention provides pressure sensors for use in wet environments. A pressure sensor package according to the invention has a housing having a pair of cavities separated by a wall member. Sequentially contained within one cavity is a conductive elastomeric seal pad, a pressure sensor and an elastomeric media seal. A pressure cap is attached to the housing such that the pressure cap and the housing together form a hermetic seal. The pressure cap has a port for admitting a gas under pressure into the first cavity. A signal amplifier is positioned within the second cavity and a cover encloses the signal amplifier within the second cavity. An electrical connector through the wall member forms an electrical connection between the pressure sensor and the signal amplifier. A lead frame extends through the housing and forms electrical connections with the pressure sensor and the signal amplifier.

A ventilation system for a building in some cases includes a main HVAC blower for moving temperature-conditioned air through the building plus a smaller ventilation blower for providing fresh air. A controller regulates the ventilation blower's speed to provide a target ventilation flow rate regardless of changes in the pressure differential between the indoor and outdoor air. To ensure that the target rate is appropriate for a particular building, the target flow rate is determined based on a ventilation setting that reflects a specified number of bedrooms and a specified amount of floor space of the building.

An outdoor multi-method cooker for preparing a wide variety of different foods at the same time using selective convection, radiant, or conduction cooking operations with or without smoke, or combinations thereof, using a single heat source. The cooker has a horizontal central longitudinal chamber with a firebox at one end and a pair of stacks at the opposed end, a main oven, a pair of lateral smokeless ovens, a warming compartment, and a griddle above the firebox, all disposed transversely on the longitudinal chamber in parallel spaced relation, and a steam table along the upper portion of the longitudinal chamber. The cooker operates on the principle of equalization of natural differential pressures caused by rising warmer air, similar to the draw created by the upper portion of a fireplace, for drafting hot gases or smoke laden hot gases from the combustion source and selectively routing it through passageways into and around the various components.

The present invention provides protection for centrifugal pumps while differentiating between dangerous operating conditions (e.g. dry running, minimum flow and runout) and/or conditions where transient conditions (e.g. closed valve operation) may occur and the protection can be revoked once the condition clears. The methodology utilizes a calculated flow value which can be mathematically determined from a calibrated closed valve power vs speed curve and/or various pump and motor parameters such as speed, torque, power and/or differential pressure or from calibrated flow curves stored in the evaluation device. The calculated flow value is then compared to threshold values of flow associated with these adverse operating conditions.

Various embodiments of the invention relate generally to systems for providing active vertical control of an airship. More particularly, at least one embodiment of the invention relates to a system for actively controlling the aerostatic lift of an airship by manipulating the ratio of air to lifting gas contained within the airship, and thus the overall mass of the airship. This manipulation is accomplished by actively compressing and/or decompressing the lifting gas or internal air, with the resulting pressure differential borne primarily by the hull and/or an internal pressure tank depending upon the configuration.

An EUV light source apparatus and method are disclosed, which may comprise a pulsed laser providing laser pulses at a selected pulse repetition rate focused at a desired target ignition site; a target formation system providing discrete targets at a selected interval coordinated with the laser pulse repetition rate; a target steering system intermediate the target formation system and the desired target ignition site; and a target tracking system providing information about the movement of target between the target formation system and the target steering system, enabling the target steering system to direct the target to the desired target ignition site. The target tracking system may provide information enabling the creation of a laser firing control signal, and may comprise a droplet detector comprising a collimated light source directed to intersect a point on a projected delivery path of the target, having a respective oppositely disposed light detector detecting the passage of the target through the respective point, or a detector comprising a linear array of a plurality of photo-sensitive elements aligned to a coordinate axis, the light from the light source intersecting a projected delivery path of the target, at least one of the which may comprise a plane-intercept detection device. The droplet detectors may comprise a plurality of droplet detectors each operating at a different light frequency, or a camera having a field of view and a two dimensional array of pixels imaging the field of view. The apparatus and method may comprise an electrostatic plasma containment apparatus providing an electric plasma confinement field at or near a target ignition site at the time of ignition, with the target tracking system providing a signal enabling control of the electrostatic plasma containment apparatus. The apparatus and method may comprise a vessel having and intermediate wall with a low pressure trap allowing passage of EUV light and maintaining a differential pressure across the low pressure trap. The apparatus and method may comprise a magnetic plasma confinement mechanism creating a magnetic field in the vicinity of the target ignition site to confine the plasma to the target ignition site, which may be pulsed and may be controlled using outputs from the target tracking system.

Methods for loading a compressed fluid, such as natural gas, into and discharging the compressed fluid out of containment are provided. The compressed fluid is injected into a bottom portion of a container system for storage and/or transport until a target pressure is reached after which gas is withdrawn from an upper portion of the container system at a rate to maintain the target pressure while the compressed fluid is injected in the bottom portion. The compressed fluid is cooled through an expansion valve and by refrigerated chillers or by injecting a cold liquid of the same chemical composition as the compressed fluid, such as liquid natural gas, into the compressed fluid prior to injection into the container system. Withdrawal or discharge from the container system to a receiving facility begins with blow down from the bottom portion of the container system without a displacement fluid and continues until pressure falls below an acceptable differential pressure. The discharge stream is passed through a separator and a light gas from the separator is pressurized and injected into an upper portion of the container system to drive the compressed fluid out the bottom. The light gas is pressurized using either a compressor or a heated tank system, where two vessels operate in parallel, trapping and heating the light gas and then discharging to the container system from one while filling the other and alternating the operation between the two.

The present invention provides, e.g., apparatus comprising at least one processor; at least one memory including computer program code; the at least one memory and computer program code being configured, with at least one processor, to cause the apparatus at least to: respond to signaling containing information about an instant pressure and a flow rate of fluid being pumped in a pumping system, and obtain an adaptive control curve based at least partly on the instant pressure and flow rate using an adaptive moving average filter. The adaptive moving average filter may be based at least partly on a system flow equation: SAMA_t=AMAF(Q_t/√{square root over (ΔP_t)}), where the function AMAF is an adaptive moving average filter (AMAF), and the parameters Q and ΔP are a system flow rate and differential pressure respectively. The at least one memory and computer program code may be configured to, with the at least one processor, to cause the apparatus at least to obtain an optimal control pressure set point from the adaptive control curve with respect to an instant flow rate or a moving average flow rate as SP_t=MA(Q_t)/SAMA_t, where the function MA is a moving average filter (MA), to obtain a desired pump speed through a PID control.