摘要:
The invention relates to a fluidic system having a first volume, a second volume and a membrane geometrically separating the two volumes, which has an open-pore microstructure for the passage of a first medium and a second medium. There is a contact angle (Θ) between the interface of the media and the pore surface. A first electrical field in the region of the membrane and a first electromagnetic radiation and a first heating of the membrane define a first state (Z 1 ), in which the membrane is not wetted or is less wetted by the first medium and is more heavily wetted by the second medium such that a first contact angle Θ1 > 90° is formed between the pore surface and the interface. The first medium and the second medium and the pore surface have a surface energy of which at least one surface energy can be reversibly changed in such a way that a second contact angle Θ2
摘要:
This invention relates to a systems and methods of controlling the flow of a fluid in a capillary or microfluidic channel. A first pair of electrodes can influence the wetting of a fluid front at a relatively hydrophobic surface in the channel. A second pair of electrodes can electrolytically generate a bubble that can stop fluid flow when it contacts the hydrophobic surface. Flow of a fluid in a channel can be stopped on contact with the hydrophobic surface and restarted when an electrostatic field reduces the contact angle of the fluid at the hydrophobic surface. The electrostatic field can be removed and the fluid stopped again when an electrolytically generated bubble contacts the hydrophobic surface to reestablish the blocking contact angle of the fluid, gas and surface.
摘要:
Microfluidic system (1,2,10,11,16) comprising a first portion (3,4,24,25) and a second portion (5-7,17-19), said first portion (3,4,24,25) comprising a material which is able to change its volume when activated by an exciting factor, characterized by the fact that said first portion (3,4,24,25) and said second portion (5-7,17-19) define a zone (3-7,17-19) which, when said first portion (3,4,24,25) is not yet activated by said exciting factor, shows a first topography and which, after activation by said exciting factor, shows a second topography (9,14), said second topography (9,14) being adapted to contain a certain amount of fluid, said microfluidic system furthermore comprising a tight cover surface (20) situated above said first portion (3,4,24,25) and said second portion (5-7).
摘要:
A method of easily controlling the flow of fluid in a micro system without using a complicated valve structure, comprising the steps of adding the substance transformed from sol to gel by stimulation to the fluid flowing through the micro flow passage of the micro system, and adding the stimulation to the fluid at a desired position on the micro flow passage to transform the fluid into gel for flow control.
摘要:
The invention concerns a freeze valve (2) for controlling the flow of small quantities of liquid in a conduit (1). Further objects of the invention are a network of conduits, a method of opening a freeze valve and a process for the separation of liquid fractions, which all involve the freeze valves (2) of the invention. The freeze valve (2) is defined by a tubular wall (3) integral with the conduit (1) and comprises a thermal bridge (4) connecting said wall to a heat sink (5), to close the valve by freezing the liquid inside the wall, as well as heating means (11) comprising a source of laser beam targeted at the wall, to open the valve by melting the frozen liquid (7). According to the invention the laser beam (13) is produced in the form of a transversally extended shroud and targeted at the wall (3) at a length extending to both sides of the point of connection (6) to the thermal bridge (4), so as to melt the block of frozen liquid (7) simultaneously along its entire length. The beam (13) can have the form of a divergent fan or flattened cone with a cross section corresponding to the elongate ice block (7) inside the wall and a radiation intensity higher in the center (15) of the beam and decreasing towards the beam edges (16). The beam can be obtained from a laser diode (11) and tailored and/or directed by optical means (12) as necessary. The network of conduits with freeze valves can be employed in analyzers for clinical chemistry, and the separation processes can be capillary electrophoresis or chromatography, where the freeze valves are used to immobilize the separated liquid samples.
摘要:
Fluid and fuel delivery systems reducing pressure fluctuation. Such systems use a conduit that attenuates pressure fluctuations. Preferably, the conduit attenuates pressure fluctuations by reflecting a portion of a pressure wave within the fluid flow so that reflected pressure waves within the flow interfere with incident pressure waves within the flow, thereby reducing the pressure fluctuations. In one embodiment, such a conduit may be formed as a quarter wave stub, in line with the fluid flow. Advantageously, exemplary of the invention, hoot noise in an engine may be reduced by damping pressure fluctuations in the fuel delivery system to the engine.
摘要:
Apparatus (10) for dispensing viscous liquid, such as hot melt adhesive, includes a manifold (14), a dispensing module (12), a heater (50) thermally coupled to the manifold (14), and thermally insulating cover structure (70, 72) secured around both the module (12) and the manifold (14). Air gaps are formed between the cover structure and the heated components inside to further reduce heat transfer. The cover structure (70, 72) may also include heat dissipating fins (70a, 72a). A supply connector (64) associated with the manifold (14) includes an interior flow passage (90), an exterior annular recess (92) and at least one port (94) communicating therebetween. A valve includes a valve seat (107) having an orifice (106) and a sealing surface located around the orifice (106). The valve further includes a valve stem (108) movable between open and closed positions and having a recess (264) in one end and a sealing edge (266) located around the recess (264). A valve module (280) includes an integrated heating element (296) for providing localized heat to the adhesive immediately prior to dispensing.