摘要:
To pump supercritical carbon dioxide into a supercritical extractor without overpressure in the reservoir and to record the volume being delivered, the pumping speed is controlled and the volume pumped is determined from a pressure-related signal used in a feedback circuit. The feedback controls the velocity of pumping in conjunction with programmed values to avoid destructive reverse torque. A cam in the pump controls piston stroke, has a depressurization portion with an initial slope equal to but in the opposite direction of the final slope, rounded transition slopes, increasing linear velocity to the refill portion and constant velocity in the refill portion.
摘要:
To provide performance particularly in handling supercritical extraction systems, a specially designed pump includes a cam-driven, single-plunger with a cam having a profile that enables the pumping system to avoid destructive reverse torque on the cam, gear train and drive motor after the cam passes top dead center. The plunger includes a seal having one side in contact with the supercritical fluid and a mechanism for supporting and aligning the piston on the other side of the seal to maintain the piston in alignment. The piston drive has Hertzian contact with the piston. The fluid volume leaving the pump is determined by measuring only pressure or other parameters related to flow and movement of the plunger. Measurement of the fluid volume leaving the pump is useful for recording or indicating the flow rate while the pump is operating.
摘要:
In a piston pump for pumping liquid carbon dioxide at a temperature below 30 degrees Fahrenheit and pressures at least as high as 7500 psi, the volume leaving the pump is determined by measuring only pressure or other parameter related to flow and movement of the plunger. The position of the piston is measured and the resulting displacement is integrated to determine volume of fluid pumped.
摘要:
To provide performance particularly in handling supercritical extraction systems, a specially designed pump includes a cam-driven, single-plunger with a cam having a profile that enables the pumping system to avoid destructive reverse torque on the cam, gear train and drive motor after the cam passes top dead center. The fluid volume leaving the pump is determined by measuring only pressure or other parameters related to flow and movement of the plunger. Measurement of the fluid volume leaving the pump is useful for recording or indicating the flow rate while the pump is operating.
摘要:
In a piston pump for pumping liquid carbon dioxide at a temperature below 30 degrees Fahrenheit and pressures at least as high as 7500 psi at an outlet flow rate in excess of 10 milliliters per minute, the inlet to the pump and the pumphead are each cooled by thermoelectric heat exchangers that are air cooled. The pump is a cam-driven, single-plunger pump with a cam profile that enables the pumping system to avoid distructive reverse torque on the cam, gear train and drive motor after the cam passes top dead center. The volume leaving the pump is determined by measuring only pressure or other parameter related to flow and movement of the plunger. The piston of the pump is supported on both sides of the seal and the support for the piston within the pumphead are machined consentrically and colinearly to the seal gland.
摘要:
To economically perform preparatory chromatography, a plurality of pumps each having a corresponding one of a plurality of pistons and a corresponding one of a plurality of cylinders are driven by one motor to draw and pump solvent simultaneously into corresponding columns. To form a gradient, the pumps are connected to two-way valves that are connected alternately to a first solvent and a second solvent, whereby the time said valve is in a first position controls the amount of solvent drawn from the first reservoir into said pumps and the amount of time in said second position controls the amount of said second solvent drawn from the second reservoir into said pumps and the solvent is mixed in the pumping systems. The detectors are photodiodes mounted to light guides in the flow cells that generate signals related to light absorbance and communicate with a controller, whereby the controller receives signals indicating solute between the light guides and causes collection of solute. An over-pressure system compensates for pressure over a predetermined level.
摘要:
A liquid chromatographic system includes columns, column mounting fixtures to which the columns are mounted, a detector, a collector, a controller and a plurality of RFIDs. A first RFID communicates with the controller and cooperating RFIDs mounted to other components provide information such as the history of components, parameters and the like. They also receive information from sensors relating to the operation of the liquid chromatograph, store the information and transmit it. Moreover, the RFIDs may substitute for hard wiring in many applications and may enable a central computer to control several liquid chromatographic system.
摘要:
A liquid chromatographic system includes columns, column mounting fixtures to which the columns are mounted, a detector, a collector, a controller and a plurality of RFIDs. A first RFID communicates with the controller and cooperating RFIDs mounted to other components provide information such as the history of components, parameters and the like. They also receive information from sensors relating to the operation of the liquid chromatograph, store the information and transmit it. Moreover, the RFIDs may substitute for hard wiring in many applications and may enable a central computer to control several liquid chromatographic systems.
摘要:
A liquid chromatographic system includes columns, column mounting fixtures to which the columns are mounted, a detector, a fraction collection system, a controller and a plurality of RFIDs. A first RFID communicates with the controller and cooperating RFIDs mounted to other components including the fraction collector to provide information such as the history of components, parameters and the like useful in maintaining inventory control and managing the system. They also receive information from sensors relating to the operation of the fraction collector including the location of sample containers.
摘要:
To form a smooth gradient and a preparatory liquid chromatographic system having a plurality of syringe type pumps, solvents are alternately drawn and inserted into each cylinder. The solvents are alternately drawn into and through a long narrow path formed of tubing to create axial mixing and spreading out of the interface and then are drawn into the cylinders during the refill stroke of the piston at a sufficiently high velocity to create turbulence. The drawing of the solvents into one side of the cylinder a radial distance from the center creates circular eddy currents.