13367 results about "Pressure difference" patented technology

A simple microfluidic actuator includes a sealed vacuum chamber actuated by providing a current to a thin film heater, which in turn weakens and, under the atmospheric pressure differential, breaks a diaphragm sealing said vacuum chamber whereby the vacuum inside said chamber is released. By applying the microfluidic actuator to a microfluidic network the resulting pressure differential can be used to generate a pumping force with the microfluidic network. The chamber may be prepared in a silicon, glass, or plastic substrate. The diaphragm may be a metallic gas-impermeable film. A releasing member comprising a thin-film metallic heater is then microfabricated on the diaphragm. The assembly so prepared may be bonded to a glass or plastic substrate that contains a network of microchannels. The microfluidic actuator is suited for a microfluidic platform in generating driving powers for operations including pumping, metering, mixing and valving of liquid samples.

The invention is generally directed to systems and methods for fluid control, and more particularly to systems and methods for power and flow rate control for aspiration. In accordance with one embodiment, an aspiration system includes an aspiration line having distal and proximal ends and an aspiration port defined in the distal end; a fluid transport device operatively coupled to the proximal end of the aspiration line; and a flow restrictor operatively coupled to the aspiration line in between the fluid transport device and the aspiration port. To measure occlusion within the line, first and second pressure sensors are utilized, the first sensor being operatively coupled to the aspiration line between the port and the restrictor and the second sensor being operatively coupled to the aspiration line between the restrictor and the fluid transport device. The pressure differential between the two sensors can provide an indication of the onset, presence, and/or elimination of an occlusion.

Disclosed is a user interface that responds to differences in pressure detected by a touch-sensitive screen. The user selects one type of user-interface action by “lightly” touching the screen and selects another type of action by exerting more pressure. Embodiments can respond to single touches, to gestural touches that extend across the face of the touch-sensitive screen, and to touches in which the user-exerted pressure varies during the course of the touch. Some embodiments respond to how quickly the user changes the amount of pressure applied. In some embodiments, the location and pressure of the user's input are compared against a stored gesture profile. Action is taken only if the input matches “closely enough” to the stored gesture profile. In some embodiments, a notification is sent to the user when the pressure exceeds a threshold between a light and a heavy press.

Methods and apparatus are provided for removing emboli during an angioplasty, stenting or surgical procedure comprising a catheter having an occlusion element, an aspiration lumen, and a blood outlet port in communication with the lumen, a guide wire having a balloon, a venous return sheath with a blood inlet port, and tubing that couples the blood outlet port to the blood inlet port. Apparatus is also provided for occluding the external carotid artery to prevent reversal of flow into the internal carotid artery. The pressure differential between the artery and the vein provides reverse flow through the artery, thereby flushing emboli. A blood filter may optionally be included in-line with the tubing to filter emboli from blood reperfused into the patient.

Disclosed is a user interface that responds to differences in pressure detected by a touch-sensitive screen. The user selects one type of user-interface action by “lightly” touching the screen and selects another type of action by exerting more pressure. Embodiments can respond to single touches, to gestural touches that extend across the face of the touch-sensitive screen, and to touches in which the user-exerted pressure varies during the course of the touch. Some embodiments respond to how quickly the user changes the amount of pressure applied. In some embodiments, the location and pressure of the user's input are compared against a stored gesture profile. Action is taken only if the input matches “closely enough” to the stored gesture profile. In some embodiments, a notification is sent to the user when the pressure exceeds a threshold between a light and a heavy press.

Methods and apparatus are provided for removing emboli during an angioplasty, stenting or surgical procedure comprising a catheter having an occlusion element, an aspiration lumen, and a blood outlet port in communication with the lumen, a guide wire having a balloon, a venous return catheter with a blood inlet port, and tubing that couples the blood outlet port to the blood inlet port. Apparatus is also provided for occluding the external carotid artery to prevent reversal of flow into the internal carotid artery. The pressure differential between the artery and the vein provides reverse flow through the artery, thereby flushing emboli. A blood filter may optionally be included in-line with the tubing to filter emboli from blood reperfused into the patient.

A protective case for an electronic device includes a main housing and a lid. The main housing and lid are removably joined to define a water tight volume receiving an electronic device. Air trapped within the protective case transfers acoustic energy from a sound source within the case to at least one membrane wherein the membrane vibrates in response to an air pressure differential transmitting sound to an exterior of the case.

An on demand tankless water heater system that is capable of quickly delivering water within a desired temperature range. The tankless water heater provides a hybrid heating method that contains a primary heating system and a secondary heating system disposed in a buffer tank that cooperate to facilitate control of output water temperature during water usage. A pressure differential switch detects low flow demand and allows the secondary heating system to provide immediate heating to the water. This secondary heating system provides a faster temperature response and fine tuning of output water temperature.

Method for controlling an assist pump for fluid delivery systems with pulsatile pressure. If for example a heart assist pump is driven with a constant number of revolutions, it is achieved, that the blood is also delivered through the assist pump, even when the heart chamber is in the decontraction phase. With the present method it is achieved, that an assist pump only acts supportingly in the pressure phase of the main pump, in such a way, that the pressure difference between the input side and the output side of the assist pump is continuously determined and the number of revolutions of the assist pump is controlled in such a way, that the determined pressure difference does not fall below a predetermined value and the rate of flow does not sink below zero.

An access device adapted and configured to be inserted through a natural biological orifice, and related surgical methods are provided. The access device includes a body, a nozzle means and means for delivering a pressurized flow of fluid to the nozzle means. The body is configured and dimensioned to be inserted through a natural bodily orifice and has proximal and distal end portions and defines at least one lumen therethrough to accommodate passage of one or more surgical instruments. The nozzle means is operatively associated with the body for directing pressurized fluid into the lumen to develop a pressure differential in an area within a region within the lumen to form a fluid seal around the one or more surgical instruments passing therethrough.

A method and apparatus for obstructing the passage of fluid within a fluid flow conduit and subsequently reconfiguring the tool to allow substantially full-bore passage therethrough. Pressure developed upstream of the obstruction can be utilized to operate pressure actuated tools such as liner hangers. Equipment used in subsequent wellbore operations such as drill pipe darts can pass undamaged through the opened port. In an embodiment, the flow through a tubular is obstructed by placing a ball on an expandable ball seat, developing a pressure differential across the ball seat, equalizing the pressure after the hydraulically actuated tool completes its function, and mechanically manipulating the drill string to open the expandable ball seat and allow the ball to pass through.

Methods and apparatuses for detecting full waste canister and/or fluid flow path blockage conditions are disclosed. Also disclosed are methods and apparatuses for controlling a pump. In some embodiments, flow of fluid can be restricted in a portion of the fluid flow path. A controller can be configured to compare a difference in pressure values upstream and downstream of a fluid flow restrictor to a pressure difference threshold, and determine based on the comparison whether to activate an alarm indicating the full waste canister condition or the fluid flow path blockage condition. The controller can be additionally or alternatively configured to determine a fluid flow using a flow meter, open a selectable valve in response to a comparison of the fluid flow with a fluid flow threshold, determine fluid flow after opening the valve, and determine based on the fluid flow after opening the valve whether to activate the alarm.

The present invention pertains to a pressure support system in which a flow or volume of gas is measured without using a dedicated flow element used in a conventional flow meter. Instead, the present invention provides a tortuous gas flow path in which a pressure differential is created between two points in the tortuous path. This pressure differential created by the gas flow path provides the necessary pressure drop for measuring the gas flow and/or gas volume passing through the pressure support system.

A gas delivery system comprising a pressure generator, a pressure sensor, a control valve, and a processor. The pressure generator pressurizes breathable gas for delivery to a patient. The pressure sensor measures a pressure difference between the pressurized breathable gas and atmospheric pressure. The control valve is disposed downstream from the pressure generator and is constructed and arranged to control a flow rate of the pressurized breathable gas. The processor controls the control valve to bring the flow rate of the pressurized breathable gas to substantially zero while the pressure generator is operating and, when the flow rate is substantially zero, determines at least one of atmospheric pressure, an atmospheric air density, or a density correction factor based at least in part on the pressure difference between the pressurized breathable gas and the atmospheric pressure.

An operating tool uses programmed fluid logic provided by use of flow paths including pre-determined spaced ports and varying orifice sizes to provide discreet pressures and fluid flow rates upon pressure differential sensitive devices, such as a membrane or piston, in operative communication with an operative sleeve to manipulate one or more secondary tools, and/or to perform a service, such as, for example, acidzing or stimulation or injecting proppants within the well. The tool remains “immune” to internal well hydraulic or hydrostatic pressures, if desired, until the fluid logic is achieved. The fluid logic is adjustable for activation of tools sequentially by making changes in the port spacing and fluid relief profiles so that all tools can be actuated by a single geometry of fluid flow paths, or each tool can have its own unique fluid flow geometry so it becomes hydraulically coded.