Abstract: An x-ray sedimentation particle size analyzer in which data is taken only at particular positions along the sedimentation cell, and each such position is individually calibrated. Presentation of the data in the form of a particle size distribution curve can be accomplished very accurately using interpolation techniques. The sedimentation cell design is free of the effects of undesirable density gradients, capable of detecting and removing bubbles, capable of attaining a highly uniform dispersion of sample prior to sedimentation, and including a safety interlock device for blocking x-ray projection when the cell is being accessed.

Abstract: An x-ray sedimentation particle size analyzer in which data is taken only at particular positions along the sedimentation cell, and each such position is individually calibrated. Presentation of the data in the form of a particle size distribution curve can be accomplished very accurately using interpolation techniques. The sedimentation cell design is free of the effects of undesirable density gradients, capable of detecting and removing bubbles, capable of attaining a highly uniform dispersion of sample prior to sedimentation, and including a safety interlock device for blocking x-ray projection when the cell is being accessed.

Abstract: An automatic sample feeder system for handling suspended samples is disclosed, and is particularly useful in connection with a sedimentation particle size analyzer. The system is capable of dispersing a particulate sample into suspension without preliminary sample preparation, maintaining a sample in suspension at the time of delivery of the sample to an analyzer, consistently delivering an acceptable concentration of a suspended sample, and cleaning and flushing its components between samples to avoid contamination. In the disclosed embodiment, sample beakers are arrayed on a rotatable tray, and a sample preparation and delivery assembly consisting of an ultrasonic probe, a stirrer blade, and a dip tube are indexed into position over the beakers in a preprogrammed sequence, and lowered into the beaker for preparation and withdrawal of the sample. The components are rinsed by directing clear liquid back through the dip tube onto the rotating stirrer blade, scattering the liquid.

Abstract: An apparatus for maintaining a constant temperature within a vessel immersed in a liquid by surrounding a portion of the vessel, extending above the surface of the liquid, with a wick. The wick conducts liquid up to a predetermined point on the vessel and maintains the liquid at that point, regardless of changes in the level of the liquid due to evaporation. The wick is encased within a layer of heat insulating or heat conducting material to further aid in maintaining a constant temperature within the vessel. A second embodiment, including alternating layers of heat conducting and heat insulating material, is disclosed for increased temperature control. The disclosed apparatus is particularly useful for maintaining a constant temperature within a vessel attached to a scientific instrument, such as a pore volume and surface area analyzer.

Abstract: A fractionating apparatus under microprocessor control including a tumbler having a series of screens of progressively larger openings around its periphery. A sample of particulate material is passed successively through each of the screens by incremental rotation of the tumbler. To aid in classifying the fractions, a spray of fluid is projected against the screens and a rocking motion is imparted to the tumbler. The smallest fraction, not being retained, is entrained in a moving stream of fluid and passed directly to a porous weighing member. When this entire fraction is deposited and weighed, the next larger fraction is accumulated in the weighing member. These individual weights and their sum are recorded and from them size percentages are computed.

Abstract: Particles suspended in a fluid medium are separated into isolated fractions by size by passing a suspension of such particles through an unobstructed passageway, the particles emerging from the passageway in decreasing order of size.

Abstract: Sample introduction apparatus useful in liquid chromatography and including a valve body having at least one fluid passage of precisely defined volume to receive a sample material and having another fluid passage delivering carrier liquid to a liquid chromatograph. The valve body can be manipulated to place the precisely defined volume in the chromatograph fluid circuit, so that the sample contained within the volume is positively displaced into the chromatograph.

Abstract: A sample of particulate material is entrained in a moving body of fluid and the fluid is continuously discharged through a porous weighing member. Before passing to the weighing member sized fractions within the sample, except for the smallest one, are separated and held back at different regions in the body of fluid so that only the one fraction initially deposits on the weighing member. The weight addition of this fraction is measured and then a further fraction is re-entrained to move with the fluid to pass to and deposit on the weighing member cumulatively with the first fraction. The weight increase caused by this further deposition is measured and the re-entrainment and weight increase measurement of still further fractions are effected separately and successively until all fractions are deposited on the weighing member. These individual weights and their sum are recorded either manually or automatically and from them size percentages are computed.

Abstract: Apparatus used in the field of liquid chromatography. There is disclosed pump apparatus for continuously delivering a flow of carrier liquid either at a constant rate of flow or at a constant pressure. The pump apparatus includes a pair of differential-piston pressure intensifiers which are sequentially operated so that the high-pressure sides of the pressure intensifiers sequentially supply carrier liquid to the chromatograph column. Each pressure intensifier is sequentially operated by a constant-rate of flow application of hydraulic liquid, with essentially pulseless operating transition between pressure intensifiers occurring during constant-pressure application of hydraulic liquid to both of the pressure intensifiers at a pressure measured during previous constant-volume hydraulic operation. An embodiment of the pump apparatus pumps plural carrier liquids in desired fixed or variable proportions.

Abstract: An apparatus for maintaining a constant temperature within a vessel immersed in a liquid by surrounding a portion of the vessel, extending above the surface of the liquid, with a wick. The wick conducts liquid up to a predetermined point on the vessel and maintains the liquid at that point, regardless of changes in the level of the liquid due to evaporation. The wick is encased within a layer of heat insulating or heat conducting material to further aid in maintaining a constant temperature within the vessel. A second embodiment, including alternating layers of heat conducting and heat insulating material, is disclosed for increased temperature control. The disclosed apparatus is particularly useful for maintaining a constant temperature within a vessel attached to a scientific instrument, such as a port volume and surface area analyzer.