35 results about "Pressure-driven flow" patented technology

Microfluidic systems and methods including those that provide control of fluid flow are provided. Such systems and methods can be used, for example, to control pressure-driven flow based on the influence of channel geometry and the viscosity of one or more fluids inside the system. One method includes flowing a plug of a low viscosity fluid and a plug of a high viscosity fluid in a channel including a flow constriction region and a non-constriction region. In one embodiment, the low viscosity fluid flows at a first flow rate in the channel and the flow rate is not substantially affected by the flow constriction region. When the high viscosity fluid flows from the non-constriction region to the flow constriction region, the flow rates of the fluids decrease substantially, since the flow rates, in some systems, are influenced by the highest viscosity fluid flowing in the smallest cross-sectional area of the system (e.g., the flow constriction region). This causes the fluids to flow at the same flow rate at which the high viscosity fluid flows in the flow constriction region. Accordingly, by designing microfluidic systems with flow constriction regions positioned at particular locations and by choosing appropriate viscosities of fluids, a fluid can be made to speed up or slow down at different locations within the system without the use of valves and / or without external control.

Disclosed is a microfluidic assay system and methods that apply flow injection analysis to permit dispersion monitoring. A solution containing a reagent that binds an analyte and a tracer is delivered via pressure-driven flow into the receiving end of the injection channel of the system of the invention. A sample fluid suspected of containing the analyte is delivered into the upstream end of the input channel under conditions permitting flow of the sample fluid toward the downstream end of the assay channel and permitting dispersion of the reagent into the sample fluid. The amount of tracer present in the fluid as it passes over the reference region and the capture region and the amount of binding between the analyte and the capture region are detected. The amount of binding detected between the analyte and the capture region is correlated to the amount of tracer detected in the reference region.

A pressure actuated flow control valve for an infusion catheter permits gravity flow of a liquid through the catheter and into a patient while resisting back flow of blood from the patient and into the catheter. The valve has a hemispherical body with an outstanding circumferential flange and a normally closed, diametric slit. The slit is longer on the convex outer surface than on the concave inner surface. Dome thickness diminishes in the area adjacent the slit, reducing total apical deflection upon collapse of the slit toward the concave surface. An inner orthogonal rib biases the slit closed. Upon application of a predetermined pressure, the slit opens toward the concave surface to permit forward fluid flow. At lower pressures, the slit closes to check fluid flow. Greater reverse pressure is required to collapse the slit toward the concave surface to permit reverse fluid flow.

The invention features microfluidic devices that contain structures that impart differential resistance to a fluid flow. The structures are disposed adjacent to intersections of channels. Devices of the invention provide differential resistance, e.g., under electric-field-driven flow and pressure-driven flow.

Electroosmotic flow controllers and methods of fluid flow control are described. The invention uses an electroosmotically generated flow component in conjunction with a pressure driven flow component to modulate fluid flow. The devices and methods of the invention may include salt bridges for making electrical connection between a power supply and a channel filled with a porous dielectric material and a fluid. Embodiments including flow controllers and flow splitters are described as is their use in a variety of fluid handling applications.

The present invention provides a device and methods of use thereof in concentrating a species of interest and / or controlling liquid flow in a device. The methods make use of a device comprising a fluidic chip comprising a planar array of channels through which a liquid comprising a species of interest can be made to pass with at least one rigid substrate connected thereto such that at least a portion of a surface of the substrate bounds the channels, and a high aspect ratio ion-selective membrane is embedded within the chip, attached to at least a portion of the channels. The device comprises a unit to induce an electric field in the channel and a unit to induce an electrokinetic or pressure driven flow in the channel.

A safety valve features a flow tube operated flapper for the normal open and closed positions that can be obtained with one or two control lines to a principal operating piston. Pressure applied to the piston moves the flow tube to rotate the flapper open behind the flow tube. Release of pressure to the principal piston allows a closure spring to return the flow tube up to let the flapper close. A secondary piston can drive the flow tube with applied pressure through a control line. Cycling the applied pressure in combination with an indexing mechanism allows the flapper to be locked open and then released to normal operation. The pistons act as backup for each other as they both drive the flow tube. The flow tube has a clearance fit to the body in the locked open position to exclude debris from the flapper.

Disclosed is an apparatus and method for the mixing of two microfluidic channels wherein several wells are oriented diagonally across the width of a mixing channel. The device effectively mixes the confluent streams with electrokinetic flow, and to a lesser degree, with pressure driven flow. The device and method may be further adapted to split a pair of confluent streams into two or more streams of equal or non-equal concentrations of reactants. Further, under electrokinetic flow, the surfaces of said wells may be specially coated so that the differing electroosmotic mobility between the surfaces of the wells and the surfaces of the channel may increase the mixing efficiency. The device and method are applicable to the steady state mixing as well as the dynamic application of mixing a plug of reagent with a confluent stream.

The present invention generally relates to systems and methods for pressure driven flow crystallization. In some embodiments, the system comprises a comprising a cavity and a mixing mechanism. In some embodiments, one or more inlets facilitate the transfer of one or more reagent streams to the cavity. In some such embodiments, the mixing mechanism mixes the first and second reagent streams such that a continuous crystallization and / or generation of a product (e.g., solid particles) in the fluid.

There is disclosed herein a method and apparatus for using rupture pins to selectively open jets on a jet perforating tool. Rupture pins inserted in jets within a jet perforating tool are configured to rupture at pre-designed thresholds, thereby opening the jet to begin a perforating job, or to circulate fluid through the tool. Also disclosed are systems and methods for holding the rupture pins within the tool prior to rupture.

The present invention provides a device and methods of use thereof in concentrating a species of interest and / or controlling liquid flow in a device. The methods make use of a device comprising a fluidic chip comprising a planar array of channels through which a liquid comprising a species of interest can be made to pass with at least one rigid substrate connected thereto such that at least a portion of a surface of the substrate bounds the channels, and a high aspect ratio ion-selective membrane is embedded within the chip, attached to at least a portion of the channels. The device comprises a unit to induce an electric field in the channel and a unit to induce an electrokinetic or pressure driven flow in the channel.