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Elastomeric Valve

Easley et al. showed integrated DNA purification, PCR, electrophoretic separation and detection of pathogens in less than 30 min [116]. The assay was performed on a pressure driven four layer glass/PDMS chip with elastomeric valves. Temperature cycling for PCR was achieved by IR radiation. Only the sample lysis step was not integrated in the microfluidic chip. Detection of Bacillus anthracis from infected mice and Bordetella pertussis from a clinical sample was successfully demonstrated. [Pg.324]

For certain applications, portability and power savings outweigh the need for highly scalable, computer-controlled valving. It should be clear to those experienced in elastomeric valving on nontrivial chip-based architectures that the external hardware also becomes nontrivial in both size and complexity. A useful alternative was presented by Whitesides and coworkers, in which torque-actuated valves were used to collapse PDMS channels, thereby closing the channels to fluid flow. The mechanistic action of these valves was similar to the Quake valves, in that a pressure was applied above a thin layer of PDMS to collapse a fluidic channel. However, since the torque-actuated valves (coined as TWIST valves) relied on a miniature machine screw to collapse the channels, they did... [Pg.1157]

In writing this chapter, the intent of the authors was to provide the reader with a rudimentary knowledge of the practical aspects associated with elastomeric valving technology—one that could be directly implemented in the laboratory. At this point, the reader should have a basic understanding of the mechanics of actuation for the two featured valving methods, as well as an understanding... [Pg.1166]

Wagner et al. (3) prepared elastomeric materials consisting of biodegradable poly(urea-urethanes), (II), containing microintegrated cells that were useful as pulmonary valves, vocal chords, and blood vessels. [Pg.419]

Metered-Dose Inhalers and Nasal Aerosols Content uniformity, aerodynamic particle size distribution, microscopic evaluation, water content, leak rate, microbial bioburden, valve delivery, extractables, leachables from plastic and elastomeric components. [Pg.580]

For suction pump systems where the potential for syphoning exists should the fuel feed line be broken when the dispenser is in operation, some jurisdictions require a valve that allows fuel flow from the tank only when the dispenser is in operation. These valves are typically made from brass and have an elastomeric diaphragm used to open the valve. The diaphragm within the valve must be methanol-compatible or it will rupture, causing the pump to draw air and lose prime. The valves should be nickel-plated and the diaphragm replaced with one made from teflon [4.4],... [Pg.102]

Seat The pressure-containing contact between the fixed and moving portions of the pressure-containing elements of a valve. It may be made of metallic, plastic or elastomere material. [Pg.54]

Microstructures and systems are typically fabricated from rigid materials, such as crystalline silicon, amorphous silicon, glass, quartz, metals and organic polymers. Elastomeric materials can be used in applications where rigidity is a drawback. We have demonstrated the concepts of elastomeric systems by fabrication of photothermal detectors, optical modulators and light valves. We believe that elastomeric materials will find additional applications in the areas of optical systems, micro analytical systems, biomaterials and biosensors. [Pg.16]

FIGURE 3.27 An elastomeric peristaltic pump using three valve control channels. The fluidic channel is 100 pm wide and 10 pm high. Dimension of microvalve control channels = 100 pm by 100 pm by 10 pm applied air pressure = 50 kPa. Peristalsis was typically actuated by the pattern 101, 100, 110, 010, Oil, 001, where 0 and 1 indicate valve open and valve closed, respectively [167]. Reprinted with permission from the American Association for the Advancement of Science. [Pg.82]

The possibility 1 is determined by the fluid and normally not influentual but effective. The use of elastomeric sealings often fails because of their limited chemical stability. Therefore elastic and mass improved valve bodies (combined with optimal springs) are the best and universal solution. [Pg.597]

Moving up to Class V entails using a seat ring containing a TFE (tetrafluoroethylene) or elastomeric disk (Part c of the figure). Less seat load is required, but the valve s temperature limits are significantly reduced. The soft seat is also more subject to damage from erosive particles, and is more expensive than a simple metal one. [Pg.85]


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See also in sourсe #XX -- [ Pg.435 ]




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