Abstract: A wear-resistant and chemically-inert article made from a sintered mixture of polytetrafluoroethylene, graphite fibers, and fluorinated graphite.

Abstract: In circuitry in which a digital circuit samples the output of an analog circuit, the improvement of using, during an interval prior to sampling, a solid-state switching element to dissipate the charge stored in a charge storage element (e.g., capacitor) in the analog circuit.

Abstract: A fused glass refractometer cell is disclosed in which a lens is formed by the front surface of the cell and a reflective surface is applied to the rear surface of the cell. Means are provided to limit the passage of light through the cell to the central portion of the cell.

Abstract: Apparatus for measuring changes in a physical property of a flowing fluid, including a cell through which the fluid flows, the cell having an inlet and an outlet, an inlet tube connected to the inlet of the cell, for delivering the flowing fluid to the cell, and an outlet tube connected to the outlet of the cell, for transporting the flowing fluid away from the cell, the inlet and outlet tubes being mounted in heat-exchanging relationship with each other, so as to transfer heat between the incoming and outgoing fluid and thereby reduce any temperature difference between the incoming fluid and the cell.

Abstract: Apparatus of the type including a light source directing a light beam through a measurement zone to a detector, wherein movement of the beam in a measurement direction with respect to the detector gives an indication of the measurement made in the zone, the improvement wherein the position of the beam with respect to the measurement zone is modulated through a preselected amplitude in a modulation direction, the amplitude being independent of light beam movements at the light source or in the path of the beam between the source and the modulating means, whereby the measurement can be made substantially independent of the beam movements in the modulating direction.

Abstract: A pump for precise, smooth delivery of liquid, particularly in liquid chromatography systems, featuring two liquid displacement elements mounted for reciprocating movement in chambers connected in series with two check valves, one displacement element serving to accumulate some of the liquid delivered by the first element and to deliver the accumulated liquid while the first element is refilling. Also disclosed is a fluid storage device for smoothing pulses from the pump comprising a flattened tube wound into a helix and placed within an annulus formed by an inner and an outer cylindrical wall. These cylindrical walls maintain the flattened tubing from expanding beyond its elastic strain limit.

Abstract: Novel photometric apparatus advantageously having a conical shaped flow-cell comprising a light source proximate the narrow end and a photosensitive detector at the wider end of the cell. The flow-cell adequately compensates for a lens effect that has been discovered to be a substantial factor in electro-magnetic energy absorption studies on liquid streams.

Abstract: Apparatus for measuring deflection of a light beam by sensing the beam with means providing two optical measurements, and providing an electrical output dependent upon the difference between the two measurements, with the instantaneous magnitude of each measurement being dependent upon the instantaneous deflection of the beam and upon the instantaneous intensity of the beam, the apparatus including electrical circuitry for including in the output an offset term dependent upon a scale factor and upon the instantaneous magnitude of at least one of the measurements, thereby making the offset term dependent upon the instantaneous intensity of the light beam, and means for initially zeroing the apparatus by adjusting the scale factor so as to make the output equal to a predetermined base value, whereby changes in the measurements due to changes in light beam intensity are offset by corresponding changes in the offset term, so as to thereby reduce the influence of beam intensity on the output.

Abstract: Improved liquid chromatographic apparatus and an improved process for making and utilizing a chromatographic column. By providing means to exert radial pressure on the column packing, the packing efficiency of the column is increased and is more reproducible, and greater uniformity can be achieved in column performance both among packed columns of the same kind and during the useful life of a given packed column.

Abstract: A pump for precise, smooth delivery of liquid, particularly in liquid chromatography systems, featuring two liquid displacement elements mounted for reciprocating movement in chambers connected in series with two check valves, one displacement element serving to accumulate some of the liquid delivered by the first element and to deliver the accumulated liquid while the first element is refilling.

Abstract: A chromatography cartridge stabilized by radial compression is disclosed with integral distributors each composed of two abutting thin plates, one with generally radial slits and the other with radially-displaced apertures. Also disclosed are a replaceable filter cap which fits in the cartridge inlet and a holder for radially compressing the cartridge with pressure sequentially generated by pistons and applied across a flexible sleeve.

Abstract: A cartridge is disclosed which comprises a volume of particulate packing material through which a fluid is to flow, a piece of solid porous material adjacent to the surface of the packing material though which the fluid is to enter the volume and a second piece of solid porous material adjacent to the surface of the packing material through which the fluid is to exit from the volume, and a heat-shrinkable tubing which triaxially compress the packing material into a tightly packed bed predominantly in the directions which are normal to and parallel to the direction of fluid flow through the packed bed and which extends beyond the pieces of solid porous material to form an inlet opening to and an outlet opening from the packed bed.

Abstract: A pneumatic valve apparatus comprises a cylindrical structure having opposite, outwardly facing faces. A plurality of two-position valves are located in the structure at regular angular intervals at positions about the axis of the cylindrical structure. The valves are subject to mechanical actuation by axial displacement. A spindle co-axial with the axis has a passageway for the flow of air toward each axial end of the spindle. A pair of pawls are carried by the spindle, one on each side of the faces, for limited axial displacement and rotatable with respect to the cylindrical structure about the axis. The pawls are angularly displaced from each other so that when one pawl is aligned with a valve, the other pawl is angularly and axially misaligned. Resilient means (spring 6) urge the pawls axially away from the faces.

Abstract: An automatic liquid sample-injecting apparatus using a conduit such as a hypodermic needle or pipette to suck liquid from a sample source and transfer it to an injector valve apparatus. The apparatus utilizes the optimum embodiment of the apparatus being equipped with (a) novel seal means adapted to exert a radial thrust or wiping action on the conduit and (2) novel conduit working means featuring both a drip-proof means to supply a non-contaminating solvent for washing the exterior of the needle and means to remove such solvent, all without interfering with the use of the needle in a series of automatic injections.

Abstract: An automatic liquid sample-injecting apparatus using a conduit such as a hypodermic needle or pipette to suck liquid from a sample source and transfer it to an injector valve apparatus. The apparatus utilizes the optimum embodiment of the apparatus being equipped with (1) novel seal means adapted to exert a radial thrust or wiping action on the conduit and (2) novel conduit working means featuring both a drip-proof means to supply a non-contaminating solvent for washing the exterior of the needle and means to remove such solvent, all without interfering with the use of the needle in a series of automatic injections.

Abstract: Low loss sample bottle assembly from which very small quantities of liquid can be removed safely, automatically and very nearly completely. The assembly comprises a spring mounted bottle having a small bottom compartment shaped to receive a needle and so sized with respect to the needle that substantially all liquid is forced from the compartment to an upper chamber and into the needle. The bottle is best equipped with a disposable, one piece, septum-like cap.

Abstract: A column for use in liquid chromatographic processes wherein the column is formed with an external reinforcing sleeve that has been found to contribute dimensional stability which results in surprising and important advantages in improving chromatographic performance. Another aspect of the invention comprises the preparation of the internal wall of the column which has an advantageous finish of 32 micro inches or better.

Abstract: An improved diaphragm valve, particularly adapted for applications at high pressures and in applications in which low dead volume is required. The valve has a diaphragm which is formed of a halogenated hydrocarbon polymer of a compression strength sufficient to avoid non-recoverable extrusion of the diaphragm. Use of such a valve totally avoids the work-hardening problem encountered in use of valves using metal diaphragms.

Abstract: Liquid chromatographic processing of compositions containing ionizable compounds. The chromatographic column is formed of a stationary packing having a chemical group chemically bonded thereto and a counter ion is added to the polar mobile liquid. The counter ion forms a reversible complex with at least one characterizing radical of at least one of the ionizable compounds.

Abstract: A compact pumping system especially useful in liquid chromatography wherein comprising a liquid path which is fully flushed in each stroke of a pump, a pump which provides substantially pulse-free flow, a pressure-sensor integrated into said flow path and operably connected to the control circuit of a bifilar stepping motor. This circuit is so designed that the driving current applied to the motor is only that required to pump the liquid. The avoiding of heat associated with a greater current is particularly important in forming a compact package of motor and pump for use in liquid chromatography.