Spectra-physics Gmbh

Other

Thermo Separation Products (california) Inc.

Thermo Separation Products, Inc.

Leslie A Miller

Thomas J McCall, Jr

Ronald Alan Gatten

Vance J Nau

Martin P Bradley

Duane Lee Middlebusher

Ronald E Honganen

Robert L Howe

Samuel Ascher Marquiss

Douglas H Smith

Williams G Patterson

Richard F Johnson

Allen B Rochkind

John H Henselman

A vial transport apparatus which is capable of storing and retrieving samples and then transporting them from one location in a sampling system to another without the complexity and expense of robotic arms or gripper elements is provided. A passive hook arrangement is utilized to engage the vials for transport and can be operated using a standard three motor system for transport in the X, Y, and Z directions. The hook supports the vial from beneath and at least partially surrounds the vial to entrap it during transport thereof.

Transport apparatus

A degassing system is provided and includes a module for conditioning a liquid to be analyzed. The module includes a container holding a liquid, a degassing chamber, and a holder for the liquid container mounted on top of the degassing chamber. The holder provides stability to the module and contains any liquid spills. In another embodiment, the system includes an autosampler in conjunction with a degassing unit which includes a degassing chamber, a vacuum pump, and tubing for conducting liquid through the degassing chamber, which tubing is permeable to gases in the liquid.

Methods and apparatus for degassing a liquid

An apparatus for effective vacuum degassing of a liquid is provided for liquid chromatography applications. The liquid to be degassed is heated in the vacuum chamber by a radiator of electromagnetic energy, in one embodiment, or is heated before it enters the vacuum chamber. The liquid may also be agitated while in the vacuum chamber. In a preferred form, the vacuum degassing unit includes a vacuum chamber including a vacuum pump for creating a vacuum therein, a source of liquid, and gas permeable tubing for conducting the liquid through said vacuum chamber. The tubing includes first and second larger diameter blocks having at least one hole therein interconnected by at least one length of small diameter tube to form a leak-tight seal therewith.

Methods and apparatus for effective vacuum degassing of a liquid are provided for liquid chromatography. The bottles with the liquid are mounted above the vacuum degassing unit to provide a head pressure to the LC pump and physical stability to the bottles. The liquid is heated in the vacuum chamber by a radiator of electromagnetic energy (in one embodiment, infra-red light). Alternatively the liquid is heated before it enters the vacuum chamber. The liquid is in an agitated state in the vacuum chamber. In one variation, the liquid is conducted through the vacuum chamber through tubes wound around bobbins so as to expose a greater portion of the surface area of the tubes to vacuum. Circuitry stops the vacuum pump for a duration of a chromatographic run. The circuitry controls the LC pump and the vacuum pump so as to optimize the chromatographic conditions in the liquid chromatography analytical system. The autosampler of the analytical system includes a vacuum degasser for degassing the resident solvents of the autosampler. Alternatively, the vacuum degassing unit for degassing the mobile phase is used to degas the resident solvents. The analytical system has its own vacuum chamber for extracting a gas from the sample to be analyzed. The extracted gas is used to produce chromatographic information. Components of a mixed solvent are mixed before the solvent is degassed. The vacuum chamber of the degassing unit is used in one variation to dissolve a selected gas in a mobile phase for use in chromatographic analysis. A method is provided for testing a conduit for conducting a liquid through the vacuum chamber. A selected gas is put in the conduit instead of the solvent, a vacuum level is created, and the time of decay of the vacuum level is measured to determine the contamination of the walls of the conduit.

Apparatus for degassing a liquid

A structural member is an elongated, generally rectangular panel having at least 2 substantially parallel fold lines extending the length of the panel parallel its long sides, preferably defining 3 subpanels. When the panel is folded along the fold lines, preferably by hand, the interior angles at each fold occur on the same surface of the panel, are approximately 90 degrees, and the member has a generally C-shaped cross-section when folded. At least one male/female lock holds each of the panels at a fixed angle relative to the adjacent panel, each male/female lock having a male component affixed to one of the subpanels and a mating female component affixed to the adjacent subpanel such that when said one subpanel is folded with respect to the adjacent subpanel, the male component inserts into the female component and is retained therein.

Foldable and lockable structural member fabricated from recycled plastic

There is disclosed herein an apparatus and method for controlling a dual piston pump for a liquid chromatography system so as to pump a flow of solvent through the liquid chromatography column at a constant flow rate and with a solvent composition which is substantially equal to the desired solvent composition despite changing conditions of compressibility of the solvent. The control system uses a computer which measures the time it takes the pump shaft to move through an overlap region in the pump cycle when both pistons are simultaneously pumping as normalized to the time taken by the pump to move through a constant velocity portion of the piston travel defined by the user. This time is compared to the time stored in the computer for the particular flow rate used to measure the time defined above for the pump to move through the overlap region for an incompressible solvent at low pressure as normalized to the time taken by the input piston to move through the same user defined segment of the constant velocity portion of the travel of the input piston. The ratio of these two times is then used in an algorithm to derive a correction factor for compressibility. This correction factor is then used to control the flow rate and the makeup of the solvent composition to maintain the correct values over changing conditions of solvent compressibility.

Apparatus for controlling a pump to account for compressibility of

An apparatus and method controls a dual piston pump for a liquid chromatography system so as to pump a flow of solvent through the liquid chromatography column at a constant flow rate and with a solvent composition which is substantially equal to the desired solvent composition despite changing conditions of compressibility of the solvent. A computer is used which measures the time it takes the pump shaft to move through an overlap region in the pump cycle when both pistons are simultaneously pumping as normalized to the time taken by the pump to move through a constant velocity portion of the piston travel defined by the user. This time is compared to the time stored in the computer for the particular flow rate used to measure the time defined above for the pump to move through the overlap region for an incompressible solvent at low pressure as normalized to the time taken by the input piston to move through the same user defined segment of the constant velocity portion of the travel of the input piston. The ratio of these two times is then used in an algorithm to derive a correction factor for compressibility. This correction factor is then used to control the flow rate and the makeup of the solvent composition to maintain the correct values over changing conditions of solvent compressibility.

Process for controlling a pump to account for compressibility of liquids

A sampler for taking samples from multiple sources has a fixed, non-moving needle at a sampling station. A sample vial is lifted from a tray at the sampling station. The needle pierces the septum of the vial and enters the sample as the vial is lifted toward the needle. The sample vial is also rotated as it is lifted, and a bar code reader makes a number of spaced apart, helical reads on a bar code label attached to the vial for label identification of the sample. The needle includes an inner, sample needle and an outer, gas-pressurization needle. The sample is withdrawn by the positive displacement of a syringe connected to the sample needle. The combination of the gas pressurization within the vial and the positive displacement of the syringe insures movement of the sample and accurate control of the volume removed independent of the viscosity of the sample. The vial tray mechanism for carrying the sample vials to and from the sample station includes a rotatable platter and four planetary trays carried by and rotatable on the platter. A clutch and brake drive permits the entire tray assembly to be rotated as a unit and also permits rotation of the planetary trays relative to the main platter so that any sample vial can be positioned at the sample station in any desired sequence with respect to the other sample vials.

Autosampler mechanism

A multiple piston assembly pump of the kind which provides an overlap between the flow output of the piston assemblies during a portion of the strokes of the piston assemblies incorporates a method and apparatus for reducing pulsations in the flow during the time when the pump is changing over from one piston pumping to the other piston pumping. A first fast control loop responds to pump output pressure and is operatively associated with a second slow control loop which responds to average pump speed. A sudden pump speed change is detected, and the pump is run in a constant pressure mode until the speed returns to normal.

Multiple piston pump control

A pump for producing a substantially smooth and continuous outflow of liquid at relatively high pressure has two piston assemblies flow connected in series. The first piston assembly includes a pressure piston having a long suction stroke and a relatively short and abrupt expulsion stroke. A valve at the inlet of the pressurization piston allows flow to enter (but not exit), and a valve at the outlet of the pressurization piston allows flow to exit (but not enter). The second piston assembly includes a damper piston which functions as a mechanically driven damper to smooth the outflow from the pressure piston. This smoothing is accomplished by storing of the liquid displaced by the expulsion stroke of the pressure piston and then delivering the stored pressurized liquid to the pump outlet during the suction stroke of the pressure piston. The drive for the pistons is constructed to produce an increased outflow of pressurized liquid for a short interval at the beginning of the expulsion stroke of the pressure piston to compensate for compressibility of the liquid at high pressure. At low pressure, the stepper motor drive is slowed down in response to the sensing of the increase of the outflow during this short interval to maintain the outflow smooth and continuous during this part of the cycle of operation.

Growing community of inventors

San Jose, CA, United States of America

Leslie A Miller