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:
A variable-orifice fluid restrictor for use with a supercritical extractor or chromatograph includes an inlet line for fluid at a pressure above its critical pressure, an extended tubular probe having an inner and an outer surface and a proximal and a distal end. The proximal end of the probe is disposed toward the inlet line. The distal end of the probe includes an adjustable orifice means adapted for metering the fluid and having first and second orifice members and an adjusting stem having first and second ends. The adjustable orifice means is adjacent to the outer surface of the probe and the orifice means is adjustable with the adjusting stem. The end of the adjusting stem is located at the distal end of the probe and is adapted for moving the first orifice member with respect to the second orifice member to control the adjustable orifice for varying the restriction of fluid passing through the adjustable orifice. The distal end of the probe is inside the collector and the adjusting stem extends outside of the collector.
摘要:
A variable-orifice fluid restrictor for use with a supercritical extractor or chromatograph includes an inlet line for fluid at a pressure above its critical pressure, an extended tubular probe having an inner and an outer surface and a proximal and a distal end. The proximal end of the probe is disposed toward the inlet line. The distal end of the probe includes an adjustable orifice means adapted for metering the fluid and having first and second orifice members and an adjusting stem having first and second ends. The adjustable orifice means is adjacent to the outer surface of the probe and the orifice means is adjustable with the adjusting stem. The end of the adjusting stem is located at the distal end of the probe and is adapted for moving the first orifice member with respect to the second orifice member to control the adjustable orifice for varying the restriction of fluid passing through the adjustable orifice.
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 reduce tailing, the frit at the outlet to the liquid chromatographic column has a diameter substantially equal to that of the inside diameter of the outlet end of the column and less than two millimeters. It is held directly against the packing of the column within a cylindrical member having a shoulder with a central aperture at least the size of the diameter of the frit and cylindrical walls which are fastened to resist force in the direction of the axis of the column from its inlet to its outlet. A gasket seals the cylindrical holder against the column wall. The frit is formed of gold-plated nickel spheres sintered together at a temperature lower than the gold-nickel eutectic temperature of 950 degrees Celsius but above the phase-immiscibility temperature of 720 degrees Celsius. The size and shape of the frit is selected to reduce tailing by causing the flow path from the column to be uniform.
摘要:
An automatic variable-orifice fluid restrictor for use with a supercritical extractor having a collection trap or a supercritical chromatograph includes an inlet line for fluid at a pressure above its critical pressure, an extended tubular probe having an inner and an outer surface and a proximal and a distal end. The proximal end of the probe carries an inlet connected to the inlet line and is outside of the trap. The distal end of the probe includes a variable orifice means adapted for metering the fluid. The variable orifice means is adjacent to the outer surface of the probe and is located in the midst of the trap. The variable orifice means is adjusted by an adjusting stem having first and second ends. The first end of the adjusting stem is connected to automatic control means such as a servo at the proximal end of the probe and outside of the trap. The second end of the adjusting stem varies the area of the orifice by moving a first orifice member. The stationary second orifice member cooperates with the first orifice member to form the orifice. The first orifice member moves axially when the orifice is closed and moves both axially and rotationally when the orifice is open or partially open. This cleans deposits from the orifice without damaging the orifice parts by high pressure notional physical contact.
摘要:
A variable-orifice fluid restrictor for use with a supercritical extractor or chromatograph includes an inlet line for fluid at a pressure above its critical pressure, an extended tubular probe having an inner and an outer surface and a proximal and a distal end. The proximal end of the probe is disposed toward the inlet line. The distal end of the probe includes an adjustable orifice means adapted for metering the fluid and having first and second orifice members and an adjusting stem having first and second ends. The adjustable orifice means is adjacent to the outer surface of the probe and the orifice means is adjustable with the adjusting stem. The end of the adjusting stem is located at the distal end of the probe and is adapted for moving the first orifice member with respect to the second orifice member to control the adjustable orifice for varying the restriction of fluid passing through the adjustable orifice.
摘要:
To inject sample into an electrophoresis capillary tube having a separating medium, the end of the capillary tube is inserted in an injection block with a liquid tight seal and a syringe is inserted into the block to apply fluid to the end of the capillary tube. The injection block provides split flow injection. A high voltage isolated switching arrangement switches the end of the capillary from the injection block to buffer at a high electrical potential to accomplish the electrophoretic separation. A second injection block is used to purge the capillary tube and can be used to supply separating medium as needed.
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.