Abstract: A device for performing the manipulation of particles suspended in a fluid is disclosed. The device comprises a duct for the flow of a fluid in which particles are suspended, an acoustic transducer, and a reflector for establishing an acoustic standing wave field across the width of the duct. It has been unexpectedly found that optimum performance of the device occurs when the spacing between the transducer and a reflector is 300 microns or less. The device seeks to overcome prior engineering difficulties that prevented one from observing the individual particle bands or separating the individual particle bands from the duct.

Abstract: Apparatus for microbial disruption, comprises a cylindrical transducer having a beat conducting, solid transmission layer disposed along at least a part of the inner longitudinal surface thereof, said transmission layer or said transducer and transmission layer defining a channel for receipt of a liquid sample, and means capable of delivering an alternating potential to said transducer at a frequency and voltage exciting resonance and inducing cavitation in said liquid sample.

Abstract: A device for performing the manipulation of particles suspended in a fluid is disclosed. The device comprises a duct for the flow of a fluid in which particles are suspended, an acoustic transducer, and a reflector for establishing an acoustic standing wave field across the width of the duct. It has been unexpectedly found that optimum performance of the device occurs when the spacing between the transducer and a reflector is 300 microns or less. The device seeks to overcome prior engineering difficulties that prevented one from observing the individual particle bands or separating the individual particle bands from the duct.

Abstract: There is disclosed apparatus for directing particles entrained in a fluid, comprising a chamber having a first wall, including means for generating a sound wave having a frequency v, and a second, opposite wall capable of reflecting the sound wave in which the first and second wall define a conduit for the passage of the fluid, and in which the thickness of the second wall is such that the path length of the standing wave in the second wall is a multiple of about ½ the wavelength ?r of the sound wave therein.

Abstract: A device for performing the manipulation of particles suspended in a fluid is disclosed. The device comprises a duct for the flow of a fluid in which particles are suspended, an acoustic transducer, and a reflector for establishing an acoustic standing wave field across the width of the duct. It has been unexpectedly found that optimum performance of the device occurs when the spacing between the transducer and a reflector is 300 microns or less. The device seeks to overcome prior engineering difficulties that prevented one from observing the individual particle bands or separating the individual particle bands from the duct.

Abstract: A device for performing the manipulation of particles suspended in a fluid, comprises a chamber forming a duct for the flow of the fluid, and an acoustic transducer (10) and a reflector (12) for establishing an acoustic standing wave field across the width of the duct the spacing between the transducer and reflector is 300 microns or less. With such a small spacing, the device is particularly effective at concentrating the particles and lower operating voltages are required.

Abstract: An apparatus which manipulates particles suspended in a fluid includes a duct for the flow of the fluid in which the particles are suspended, and a mechanism for establishing an acoustic standing wave field across the width of the duct, the duct being formed with an expansion in width downstream of the standing wave field. In use, the particles in the fluid are displaced into a series of parallel bands by the acoustic standing wave field. The particles remain in these bands as the fluid flows downstream from the section in which the standing wave field is present. When the fluid reaches the expansion of the duct, the stream of fluid expands accordingly in width and, in so doing, the bands of particles are spread further apart, so increasing the spacing between adjacent bands. The bands can then be observed or separated from the duct.

Abstract: A sample of liquid with suspended particles is contained in a tube and subjected to a standing wave ultrasound field transverse to the tube, the standing wave exhibiting a progressive change in pressure amplitude transverse to the tube, so that particles in suspension are displaced transversely of the tube to one or more predetermined regions; exposure of the sample to the standing wave is then terminated and the particles are allowed to settle, and inspected to determine whether they remain aggregated or whether they dissociate. The ultrasound field is produced by a transducer of tubular form encircling the tube. The invention may be used for agglutination of particles or cells via cross-bridging molecules in immuno-agglutination assays.

Abstract: A sample of liquid with suspended particles is contained in a tube and subjected to a standing wave ultrasound field transverse to the tube, the standing wave exhibiting a progressive change in pressure amplitude transverse to the tube, so that particles in suspension are displaced transversely of the tube to one or more predetermined regions; exposure of the sample to the standing wave is then terminated and the particles are allowed to settle, and inspected to determine whether they remain aggregated or whether they dissociate. The ultrasound field is produced by a transducer of tubular form encircling the tube. The invention may be used for agglutination of particles or cells via cross-bridging molecules in immuno-agglutination assays.