WO2012177259A1 - Régulateur de pression d'évaporation à faible bruit pour chromatographie de fluides supercritiques - Google Patents

Régulateur de pression d'évaporation à faible bruit pour chromatographie de fluides supercritiques Download PDF

Info

Publication number
WO2012177259A1
WO2012177259A1 PCT/US2011/041711 US2011041711W WO2012177259A1 WO 2012177259 A1 WO2012177259 A1 WO 2012177259A1 US 2011041711 W US2011041711 W US 2011041711W WO 2012177259 A1 WO2012177259 A1 WO 2012177259A1
Authority
WO
WIPO (PCT)
Prior art keywords
diaphragm
seat
flow channel
pressure
nozzle
Prior art date
Application number
PCT/US2011/041711
Other languages
English (en)
Inventor
Terry A. Berger
Samuel O. Colgate
Michael A. Casale
Original Assignee
Aurora Sfc Systems, Llc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Aurora Sfc Systems, Llc filed Critical Aurora Sfc Systems, Llc
Priority to PCT/US2011/041711 priority Critical patent/WO2012177259A1/fr
Publication of WO2012177259A1 publication Critical patent/WO2012177259A1/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02—Column chromatography
    • G01N30/26—Conditioning of the fluid carrier; Flow patterns
    • G01N30/28—Control of physical parameters of the fluid carrier
    • G01N30/32—Control of physical parameters of the fluid carrier of pressure or speed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D11/00—Solvent extraction
    • B01D11/02—Solvent extraction of solids
    • B01D11/0203—Solvent extraction of solids with a supercritical fluid
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D11/00—Solvent extraction
    • B01D11/02—Solvent extraction of solids
    • B01D11/0207—Control systems
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D16/00—Control of fluid pressure
    • G05D16/024—Controlling the inlet pressure, e.g. back-pressure regulator
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D16/00—Control of fluid pressure
    • G05D16/04—Control of fluid pressure without auxiliary power
    • G05D16/06—Control of fluid pressure without auxiliary power the sensing element being a flexible membrane, yielding to pressure, e.g. diaphragm, bellows, capsule
    • G05D16/063—Control of fluid pressure without auxiliary power the sensing element being a flexible membrane, yielding to pressure, e.g. diaphragm, bellows, capsule the sensing element being a membrane
    • G05D16/0644—Control of fluid pressure without auxiliary power the sensing element being a flexible membrane, yielding to pressure, e.g. diaphragm, bellows, capsule the sensing element being a membrane the membrane acting directly on the obturator
    • G05D16/0647—Control of fluid pressure without auxiliary power the sensing element being a flexible membrane, yielding to pressure, e.g. diaphragm, bellows, capsule the sensing element being a membrane the membrane acting directly on the obturator using one membrane without spring
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02—Column chromatography

Definitions

  • the present invention relates to methods and systems for controlling pressure of a mobile phase flowstream within chromatography and extraction systems, such as liquid chromatography, supercritical chromatography, and supercritical extraction systems, with a back pressure regulator.
  • Supercritical fluid chromatography is a separation technique similar to high performance liquid chromatography (HPLC), except one of the fluids used as a solvent is a highly compressible liquefied gas.
  • Supercritical fluid extraction is a related technique but with somewhat lower requirements for accurate flow or pressure control.
  • the most common fluid used in SFC (and SFE) is carbon dioxide, which will be considered as representative of all such fluids.
  • carbon dioxide is a low density gas (density approximately 0.002g/cm3).
  • carbon dioxide for SFC and SFE characteristics of carbon dioxide for SFC and SFE are only achieved when the carbon dioxide is held at a liquid-like density, usually between 0.6 and 1.0g-cm-3, by raising it's pressure to 80 to 600 Bar, while keeping the temperature in the general range of 20° to 100°C, and more commonly between 35 to 60°C. Under such conditions, the carbon dioxide: 1.) acts as a solvent, 2.) exhibits very high solute binary diffusion coefficients (allows higher flow rates than in HPLC), and 3.) exhibits very low viscosity (generates lower pressure drops across columns compared to HPLC).
  • the carbon dioxide is compressed to high pressures and pumped as a liquid or as a supercritical fluid, at a liquid like density, through a separation column.
  • a back pressure regulator (BPR) is placed downstream of the separation column to keep the column outlet pressure above typically 80 Bar.
  • Detectors capable of operating under high pressure may be mounted between the column and the BPR.
  • Low pressure detectors may be mounted in the flow stream directly downstream of the BPR.
  • a BPR In order to be appropriate for use in SFC, a BPR must be stable, accurate and repeatable, with appropriately low, unswept volume, and generate low UV detector noise. In addition it should be relatively inexpensive and easy to use and maintain. Users sometimes program pressure versus time, making electromechanical control desirable. As equipment has become more and more computer controlled, it has become desirable to have all the set points stored and downloaded from a single electronic method file, making electromechanical control of the BPR even more desirable.
  • Standard mechanical back pressure regulators such as those available from Tescom, generally have a large surface in direct contact with the fluid being controlled, which allows smoother, more precise control.
  • UV detectors are the most common detector type used in SFC. UV detector response is affected by refractive index changes in the mobile phase. The refractive index of carbon dioxide is highly dependent on temperature and pressure. In the past, the most common outlet pressure used in SFC has been 100 Bar. The most common column temperature used in SFC has been 40°C. At 40°C the refractive index changes from 1.1120 at 90 Bar to 1.1606 at 110Bar, a change of over 4%. This represents a change of approximately 0.2%/Bar. Oscillations in refractive index cause the light beam passing through a UV detector cell to be bent a variable amount. Pressure fluxuations generate refractive index fluxuations which causes variations in the light hitting the photosensitive portion of the detector. It is desirable to minimize pressure fluxuations to achieve low UV detector noise.
  • the preferred and alternative embodiments of the present invention disclose a drive mechanism for a back pressure regulator used in liquid chromatography, supercritical fluid chromatography, or supercritical fluid extraction allows very fine automated control over a very wide range of pressures by combining a linear actuator compressing a spring, pushing a pin.
  • the nozzle assembly of the regulator comprises a flow through chamber containing a diaphragm and a seat, in which the pin pushes the diaphragm against the seat, together with an upstream pressure sensor and electronic feedback control to the motor of the actuator.
  • the BPR of the embodiments exhibits high pressure stability and extremely low pressure noise, even at moderate to high pressures.
  • the exemplary BPR can be use at either constant pressure or to generate pressure programs where the pressure is varied versus time.
  • the embodiments of the invention include a modular back pressure control system for chromatography systems such as supercritical fluid chromatography flow streams that allow interchange of any of the principal control elements without the need for recalibration of the device.
  • principal components including a micropositioning drive and a variable restriction nozzle cartridge may be interchanged at will to provide pressure regulation in excess of 400 bar.
  • a high precision pressure sensor is used to assist in controlling the operation of the micropositioning drive.
  • the precision of control of the regulator system can exceed typical commercial offerings by more than an order of magnitude in the critical low flow range of 0.5 to 10 mL/min that is most commonly associated with analytical flow rates in SFC and SFE.
  • the system depends on high precision registration of only four surfaces of the assembly - two on the micropositioning drive element to enforce the exposed length and end of travel limit for the end effector and two within the valve cartridge body itself to set the range of variability for the valve control. All of the surfaces are controlled simply by high precision machining tolerances and require only specified torque adjustment ranges to bring the surfaces into adequate proximity. As a result the manual assembly of the backpressure regulation system is dramatically simplified and robust.
  • micropositioning drive which may be controlled mechanically, hydraulically, thermally or electromagnetically.
  • Positional control of the drive at its end effector can be controlled in displacement steps of at most a few tenths of microns per bar of pressure change. This is best achieved by converting mechanical movement of the drive to a continuous force at the end effector. As practical matter it is highly desirable to achieve control of the end force at resolutions of tenths to hundredths of bars at the minimum step change.
  • an electric stepper motor type linear actuator is used to drive a pair of thrust elements in communication with a high force constant spring. The spring attenuates relatively large displacement steps of the stepper motor at a determined rate of force per displacement.
  • the distant thrust element is placed in communication with the drive end effector, in this case a machined metal pin, and the pin movement interacts with the nozzle cartridge to produce a pressure change.
  • Alternative means of supplying constant force to the drive end effector may include use of constant force motors, solenoids, and hydraulic or pneumatic control systems.
  • the drive system must be rapid enough to respond to significant pressure changes caused by rapid variations in viscosity and flow of the control system.
  • Figure 1 is an isometric diagram of an exemplary back pressure regulator of the embodiments
  • Figure 2 illustrates side and end views of the back pressure regulator of Figure 1 ;
  • Figure 3 illustrates various views of the nozzle assembly of the embodiments
  • Figure 4 illustrates a plan and cross-sectional view of the nozzle assembly of the embodiments
  • Figure 5 illustrates various views of a diaphragm for the nozzle assembly of the embodiments
  • Figure 6 illustrates plan views of shims used in the nozzle assembly of the embodiments
  • Figure 7 is a supercritical fluid chromatography system that is capable of implementing the embodiments of the present invention.
  • FIGS 8, 9, 10, and 11 are graphs showing results of an operation of the embodiments.
  • FIG. 1 a preferred embodiment of a back pressure regulator (BPR) assembly 10 for use in chromatographic or extraction systems such as supercritical fluid chromatography systems is illustrated in an exploded isometric view.
  • Figure 2 illustrates side, rear end, and front end views of assembled BPR 10. Mounting screws attach each of four tie rods 14 to a mounting plate on stepper motor 16 having electronic controls via connection 17.
  • BPR mounting bracket 18 provides a mounting surface for the BPR to an external housing via grommets that slide onto two of the tie rods 14.
  • Rear spring thrust element 24 is received by rear end of modified high force spring 22 and receives an actuating lead screw or pin 26 from motor 16.
  • a cylindrical spring guide 28 houses spring 22 within a framework of tie rods 14.
  • screw 30 is connected to front spring thrust element 32.
  • Bushing 34 is received into a cylindrical protrusion of nozzle mount plate 36.
  • Nozzle pin 38 is also received through nozzle mount plate 36 by bushing 34.
  • Mount plate 36 connects to front plate 40 using screws 42 or other equivalent connectors. Screws 42 connect front plate 40 to ends of tie rods 14. Heated nozzle assembly 44 is held near to nozzle pin 38 to complete the BPR assembly.
  • Electronic controller connector 45 provides computer controls and monitoring of assembly 44.
  • Nozzle insert assembly 50 comprises nozzle insert 56 which receives outlet flow tube 52 through its radial center point.
  • Inlet flow tube 54 is offset from insert 50 but parallels outlet tube 52.
  • Inlet tube 54 transfers flow into inlet channel 53 and outlet tube 52 provides an exit path for flow through outlet channel 51.
  • Nozzle insert assembly 50 additionally comprises a machined seat 56 that together with inlet tube 54 and outlet tube 52 form a brazed assembly.
  • Nozzle insert 50 contains an annular ring 57 that insets nozzle seat 56 relative to an external edge. Annular ring 56 is in fluidic
  • Nozzle seat 56 is in fluidic communication with, and provides an entrance to nozzle outlet tube 52.
  • an internal diameter for inlet channel 53 is 0.020 inches and an internal diameter for outlet channel 51 is 0.040 inches, however these dimensions are merely exemplary and may vary higher or lower.
  • FIG. 4 illustrates more detailed plan and cross-sectional views of exemplary nozzle assembly 44.
  • Nozzle body 46 receives nozzle nut 48 with a threaded connection that extends only partially into internal area of body 46.
  • Outlet channel 51 receives outlet flow tube 52 through nozzle insert's radial center point.
  • Inlet flow channel 53 is offset from seat 56 but parallels outlet channel 51.
  • Nozzle diaphragm 60 is positioned adjacent to nozzle insert 50 such that a conical or raised feature 62 (see Figure 5) is substantively coaxial to and partially contained within nozzle seat 56.
  • Nozzle diaphragm 60 is backed by spring shims 68 and 66 (see Figure 6) in a parallel and coaxial
  • shims 66 and 68 are thin, circular, metallic discs. Shim 66 can have an exemplary dimension of 0.313 x 0.005 inches and shim 68 can have larger exemplary dimension of 0.5 x 0.005 inches. As one skilled in the art recognizes, these dimensions are merely for illustration of the embodiments and can vary larger or smaller without falling outside the scope of the present invention. Smaller diameter shim 66 is located between nozzle pin 38 and larger diameter shim 68 (and further diaphragm 60).
  • the spring shims 68 and 66 and diaphragm 60 are constrained by nozzle body 46 and the nozzle insert 50.
  • the surface of nozzle body 46 adjacent to spring shim 66 may be angularly recessed relative to an undeflected, planar spring shim.
  • Nozzle nut 48 applies compressive force against nozzle insert 50 and nozzle body 46 such that a high pressure seal is made between the faces of nozzle diaphragm 60 and the surface of nozzle insert 50.
  • Exemplary nozzle insert 50 further contains two electric cartridge heaters 58 and a resistive temperature sensor 59.
  • Nozzle pin 38 provides a motive force against spring shims 68, 66 and diaphragm 60.
  • Heating element 58 is located axially within insert assembly 50 and preferably is located near to, but does not directly contact, inlet tube 54, outlet tube 52, nozzle seat 56 or any side or lower surfaces of nozzle body 46 and nozzle nut 48, however contact with the aforementioned nozzle assembly parts will not cause degradation in performance of the nozzle assembly 50.
  • Up to two heating elements 58, 58' are illustrated in plan view.
  • a temperature sensor 59 is also positioned parallel to heating elements 58 and 58'.
  • a fluid enters the nozzle via nozzle inlet tube 54 through inlet channel 53.
  • Said fluid additionally contained within annular ring 57 may provide pressure against the interior diaphragm 60 surface. Said pressure will provide force against, and may cause deflection of diaphragm 60 which is circumferencially constrained by nozzle body 46 and nozzle insert 50. Such deflection force is opposed by spring shims 68 and 66 which additionally prevent non-axial deflection of the diaphragm. Deflection of the diaphragm 60 away from nozzle seat 56 opens the nozzle to allow increased flow to outlet channel 51 and tube 52. Deflection of the nozzle diaphragm 60 towards nozzle seat 56 decreases flow.
  • Motive force on nozzle pin 38 can be provided to further oppose deflection pressure on the diaphragm 60. Increased pressure on pin 38 can cause a forward (closing) movement of diaphragm 60 toward nozzle seat 56. Such forward motive force reduces fluid flow exiting via nozzle seat 56 and nozzle outlet tube 52. Reduced flow exiting the nozzle will provide for increased pressure within annular ring 57, which provides additional pressure on the interior surface of the diaphragm, which opposes motive force on pin 38 until forces balance and a stable pressure is achieved. [0027] Within the normal operating pressure of a supercritical fluid
  • the pressure difference between the back pressure regulator and an ambient outlet vent can substantially exceed 100 bar.
  • This pressure differential is that which is experienced by the fluidic escape.
  • Such pressure difference causes state changes in escaping fluid from supercritical or dense liquid state to a gaseous state.
  • This state change represents greater than a 50:1 increase in volume as the transition occurs.
  • This expansion causes extensive evaporative cooling.
  • the addition of one or more heaters provide for addition of heat to counteract the effects of expansive cooling.
  • the heaters are placed in direct thermal communication with the area of expansive cooling; i.e. the nozzle seat 56 and the nozzle outlet channel 51 , and less directly heating the inlet channel 53 and surface of annular ring 57 and thus providing additional heat to the fluid contained within.
  • the direct addition of heat in these areas delays the rapid and significant cooling of the fluid until after the fluid exits the region in close proximity to the nozzle seat 56 and diaphragm conical feature 62.
  • Pin 38 or dimpled diaphragm 60 is pushed into an orifice 64 by compressed spring 22.
  • the spring 22 is compressed by a linear actuator comprised of stepper motor 16 and a lead screw 26.
  • the linear actuator by itself, does not possess adequate resolution to allow anything other than very crude pressure control.
  • the linear actuator in the embodiments can move less than 0.0003 inches/step or 0.0076 mm/step. However, in one embodiment, the entire distance of travel from totally open to totally closed is on the order of 25 to 40 ⁇ or 0.001 to 0.0016 inches. If the best linear resolution of the actuator is 0.0003 inches/step, there can only be three to seven different positions for controlling pressure over the range of 0-400 or 0-600 Bar.
  • each micro-step on the linear actuator represents a very small variation in force applied. For example, in one exemplary application, one thousand steps could produce 30 pounds of force, etc. In one embodiment, more than two inches of spring compression can produce more than 200 pounds of force. As an example, if the spring 22 has a spring constant of 100
  • each step of 0.0003 inches represents 0.03 pound of force.
  • Each step produces a miniscule amount of pressure perturbation.
  • the very fine control represented by each step allows smooth changes in pressure without oscillations.
  • Pressure can be programmed to produce very smooth pressure ramps. Even with using an inexpensive linear actuator, the arrangement provides the ability to control or program the outlet pressure of a chromatograph through computer control.
  • the spring 22 dampens pressure fluxuation caused by other devices, such as reciprocating pumps mounted upstream of a separation column.
  • short term pressure variations at the BPR 10 have been measured as low as 0.8 pounds per square inch (psi) with the BPR 10 controlling at 2900 psi with 3ml/min of flow consisting of 20% methanol in carbon dioxide. This represents 200 +/- 0.03Bar; ⁇ +/-0.02%, which is at least an order of magnitude superior than previously reported BPRs used in SFC.
  • This extremely low observed pressure noise significantly contributes to observed low UV detector noise.
  • nozzle assembly 44 uses dimpled diaphragm 60 pressed into a shaped orifice 64.
  • the fluid from the column outlet enters a small chamber defined by the annular ring 57, diaphragm 60, and the orifice 64 through a channel 53, and exits through the orifice into another channel 51.
  • the internal volume of the device is less than 10 ⁇ _.
  • this volumetric capacity is merely exemplary and could be larger or smaller depending upon the application.
  • the diaphragm 60 can require several hundred pounds of force to control at 400 Bar. In this case the force is provided by the drive mechanism described above. Since the stepper motor 16 is located some distance from the nozzle assembly 44 there is little to no heat transfer from the motor 16 to the nozzle assembly 44.
  • nozzle body 46 is approximately one inch in outer diameter, yet it can accommodate two 25 Watt heaters that are one inch long as well, such as an exemplary platinum resistance temperature sensor.
  • the temperature of nozzle assembly 44 is controlled by a purpose built electronic circuit with an optimized proportional, integral, differential (PID) control algorithm.
  • the pin 38 is tapered and passes through a seal before being pushed into the shaped orifice 64. Fluid enters through the same tube 54 that is attached to a column or ultraviolet ("UV") detector outlet. The fluid is in contact with a moving seal around a spring and exits through the orifice of the seat into another channel or tube. The taper on the pin produces a variable gap between the pin and orifice and produces a controllable resistance to flow.
  • UV ultraviolet
  • FIG. 7 is a schematic of a modern binary High Performance Liquid Chromatography (HPLC) or SFC system capable of implementing the embodiments of the present invention.
  • the system is comprised of a duplex pump 76 which receives a relatively incompressible fluid supply [typically high purity water or carbon dioxide ] from reservoir 74.
  • a second duplex pump 72 typically receives an organic solvent of higher compressibility from reservoir 70.
  • the two flow streams mix at a tee then continue past pulse dampener 78 and output pressure sensor 80 through diffusion tube 82.
  • the mobile phase flowstream continues to injector valve 190, which injects samples or chemical solutions for separation into the mobile phase.
  • injector valve 84 the mobile phase continues through stationary phase separation column 86, detector 88, and back pressure regulator 90, before being exhausted to waste or directed to another process such as fraction collection in preparative systems.
  • the computerized system controller 92 that directs the specific operation of the system, including elements of BPR 90, which in the specific embodiments is exemplary BPR 10.
  • each pump of the system of Figure 7 is set to an initial flow rate to produce a specific composition of mobile phase.
  • the mobile phase is allowed to equilibrate with the separation column.
  • Detectors are adjusted to recognize the signal produced at this initial state as a "baseline" value.
  • the sample loop of injector valve 84 is filled with liquid containing a mixture of dissolved components.
  • the valve is actuated to allow mobile phase to push the sample segment onto the separation column.
  • Individual components of the sample mixture experience different retention times on the separation column and emerge at different times.
  • the detector senses the components and generates an electronic signal different from the baseline value which can later be interpreted for component type and/or amount by the system controller.
  • Back pressure regulator 90 provides sufficient backpressure to prevent disturbances in the detector from outgassing of mobile phase elements.
  • the initial mobile phase composition is sufficient to separate all components of the sample in a timely manner, it is maintained over the separation period. This is referred to as isocratic separation.
  • the adsorption of some components of a sample is so strong that the initial flow composition would take inordinately long to elute the mixture.
  • a technique called gradient elution is used in these cases. Gradient elution allows the sample application and initial separation of poorly retained components to occur at the initial condition, then ramps the solvent composition to higher concentration of the stronger solvent to elute more strongly retained components. At the same time, the flow of the weaker solvent of the binary mixture is reduced to maintain a constant total flow rate.
  • the UV diode array detector wavelength ( ⁇ ) was set to 280nm with a 16nm bandwidth (BW).
  • the reference wavelength ( ⁇ ⁇ ) was 360nm with a 40nm BW.
  • the slit was set to 16 nm.
  • the electronic filter was set to >0.1 min which corresponds to a 2.5Hz data rate. UV spectra were monitored on-line to assure there was no absorbance at the wavelength used, so that all shifts in the baseline could be attributed to Rl changes.
  • the system outlet pressure was manually changed approximately every 30-45 seconds, back and forth between each two sets of pressures, while the UV signal offset, caused by the pressure perturbation, was measured. At least three steps were made at each pair of pressures. The results from a typical set of measurements are presented in Figure 10.
  • the lower trace is the system outlet pressure, just downstream of the UV detector. From left to right, there are 3 steps from 120 to 140 bar (20 bar), 3 steps from 120 to 130bar (10Bar), 3 steps from 120 to 125 bar (5Bar), 3 steps from 120 to 122 bar (2Bar), and 3 steps from 120 to 121 (1 Bar).
  • the steps are meant to emulate BPR N p-P of +/-10 Bar (20Bar), +/-5 Bar (10Bar), +/-2.5 Bar (5Bar), +/-1Bar (2Bar), and +/-0.5 Bar (1 Bar).
  • the upper trace in Figure 10 shows the UV detector signal responding to the pressure steps.
  • the amplitude of the steps is a direct measure of baseline offset caused by the pressure perturbations and ultimately by the change in the Rl of the mobile phase with pressure. These measurements were repeated with the base pressure (the initial pressure) at 90, 100, 120, 140, and 200Bar, with the 20, 10, 5, 2, and 1Bar steps superimposed.
  • UV detector offsets were the largest in the regions where the Rl (and density) changes the most with small changes in pressure, as expected. Operation at higher pressures resulted in decreased detector offsets and should also result in lower UV Np-p.
  • Some real BPR's generate as much as +/-2.5Bar pressure noise, at moderate frequencies.
  • One well known BPR uses a solenoid to oscillate a pin into an orifice between 1 and 20 Hz turning flow on and off, to control pressure.
  • a typical peak widths are 0.05 to 0.2min, on 5 im particles requiring a minimum detector data rate of 1.25 to 5Hz. Smaller particles generate narrower peaks and require higher detector frequencies.
  • the data in Figure 8 suggest BPR oscillations, at frequencies near peak frequencies, can generate baseline noise > 1 mAU (filter >0.1 min), making trace analysis under such conditions problematic.

Landscapes

  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Fluid Mechanics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Treatment Of Liquids With Adsorbents In General (AREA)

Abstract

La présente invention concerne un mécanisme d'actionnement destiné à un régulateur de pression d'évaporation convenant à la chromatographie en phase liquide, à la chromatographie de fluides supercritiques, ou à l'extraction de fluides supercritiques. Ce mécanisme permet une régulation très fine dans une plage de pressions très étendue, grâce à un actionneur linéaire combinant compression de ressort et poussée sur une tige. L'ensemble buse du régulateur comprend, non seulement une chambre d'écoulement en charge contenant une membrane et un siège, chambre dans laquelle la tige pousse la membrane contre le siège, mais aussi une sonde de pression et une commande électronique à rétroaction destinée au moteur de l'actionneur. Le régulateur de pression d'évaporation selon les modes de réalisation de l'invention s'avère stable aux pressions élevées et faire preuve d'un bruit de pression extrêmement bas, même dans le cas de pressions modérées à hautes. Le régulateur de pression d'évaporation selon l'invention peut s'utiliser, soit à pression constante, soit pour générer des programmes de pressions dans lesquels on fait varier la pression en fonction du temps. En outre, l'ensemble buse comporte une tête remplaçable sur site ne demandant aucun réglage mécanique lors du remplacement.
PCT/US2011/041711 2011-06-23 2011-06-23 Régulateur de pression d'évaporation à faible bruit pour chromatographie de fluides supercritiques WO2012177259A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/US2011/041711 WO2012177259A1 (fr) 2011-06-23 2011-06-23 Régulateur de pression d'évaporation à faible bruit pour chromatographie de fluides supercritiques

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US2011/041711 WO2012177259A1 (fr) 2011-06-23 2011-06-23 Régulateur de pression d'évaporation à faible bruit pour chromatographie de fluides supercritiques

Publications (1)

Publication Number Publication Date
WO2012177259A1 true WO2012177259A1 (fr) 2012-12-27

Family

ID=47422854

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2011/041711 WO2012177259A1 (fr) 2011-06-23 2011-06-23 Régulateur de pression d'évaporation à faible bruit pour chromatographie de fluides supercritiques

Country Status (1)

Country Link
WO (1) WO2012177259A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109939857A (zh) * 2019-03-05 2019-06-28 泉州台商投资区万鼎机械科技有限公司 一种pvc管表面自动喷涂设备
CN114487213A (zh) * 2022-04-15 2022-05-13 南京派诺思科学仪器有限公司 一种容积式液相色谱仪流量测定装置及方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5180487A (en) * 1987-09-25 1993-01-19 Nihon Bunko Kogyo Kabushiki Kaisha Pump apparatus for transferring a liquified gas used in a recycle chromatograph
US6358414B1 (en) * 1999-10-29 2002-03-19 Ontogen Corporation Pressure regulation apparatus and method for multiple channel high throughput purification
US6648609B2 (en) * 2002-04-05 2003-11-18 Berger Instruments, Inc. Pump as a pressure source for supercritical fluid chromatography involving pressure regulators and a precision orifice
US20080010956A1 (en) * 2006-07-17 2008-01-17 Fogelman Kimber D Process flowstream collection system
US20100102008A1 (en) * 2008-10-27 2010-04-29 Hedberg Herbert J Backpressure regulator for supercritical fluid chromatography
US20110233299A1 (en) * 2010-03-23 2011-09-29 Berger Terry A Low Noise Back Pressure Regulator for Supercritical Fluid Chromatography

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5180487A (en) * 1987-09-25 1993-01-19 Nihon Bunko Kogyo Kabushiki Kaisha Pump apparatus for transferring a liquified gas used in a recycle chromatograph
US6358414B1 (en) * 1999-10-29 2002-03-19 Ontogen Corporation Pressure regulation apparatus and method for multiple channel high throughput purification
US6648609B2 (en) * 2002-04-05 2003-11-18 Berger Instruments, Inc. Pump as a pressure source for supercritical fluid chromatography involving pressure regulators and a precision orifice
US20080010956A1 (en) * 2006-07-17 2008-01-17 Fogelman Kimber D Process flowstream collection system
US20100102008A1 (en) * 2008-10-27 2010-04-29 Hedberg Herbert J Backpressure regulator for supercritical fluid chromatography
US20110233299A1 (en) * 2010-03-23 2011-09-29 Berger Terry A Low Noise Back Pressure Regulator for Supercritical Fluid Chromatography

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109939857A (zh) * 2019-03-05 2019-06-28 泉州台商投资区万鼎机械科技有限公司 一种pvc管表面自动喷涂设备
CN109939857B (zh) * 2019-03-05 2020-12-29 浙江新洁新材料科技有限公司 一种pvc管表面自动喷涂设备
CN114487213A (zh) * 2022-04-15 2022-05-13 南京派诺思科学仪器有限公司 一种容积式液相色谱仪流量测定装置及方法
CN114487213B (zh) * 2022-04-15 2022-09-02 南京派诺思科学仪器有限公司 一种容积式液相色谱仪流量测定装置及方法

Similar Documents

Publication Publication Date Title
US9345989B2 (en) Low noise back pressure regulator for supercritical fluid chromatography
US20110113866A1 (en) Microengineered Supercritical Fluid Chromatography System
JP4713043B2 (ja) 高圧キャピラリ液体クロマトグラフィ溶媒送出システム
US6561767B2 (en) Converting a pump for use in supercritical fluid chromatography
US7048517B2 (en) Pump as a pressure source for supercritical fluid chromatography
Springston et al. Kinetic optimization of capillary supercritical fluid chromatography using carbon dioxide as the mobile phase
US10877497B2 (en) System and method for minimization of force variation in a solenoid within a pressurized flow system
US9618486B2 (en) Limiting a rate of pressurization in a pressurized flow system having a configurable system volume
EP2822667B1 (fr) Régulateur de pression de vanne aiguille à équilibrage des forces pour chromatographie à base de dioxyde de carbone
WO2012177259A1 (fr) Régulateur de pression d'évaporation à faible bruit pour chromatographie de fluides supercritiques
US9765896B2 (en) Low volume, pressure assisted, stem and seat vent valve and associated methods
US9341277B2 (en) Method, system and apparatus for automatic calibration of a needle valve device in a pressurized flow system
US10824174B2 (en) Pressure related hysteresis manipulation in a pressurized flow system
US20150040756A1 (en) Regulator for improved thermal and pressure control for chromatography
Janssen et al. Flow rate control in pressure‐programmed capillary supercritical fluid chromatography
WO2015029252A1 (fr) Soupape de régulation de pression et dispositif de chromatographie à fluide supercritique
US9546739B2 (en) Modular solenoid valve kits and associated methods
Küppers et al. Programming of pressure and mobile phase composition at constant flow-rate using a self-adjusting valve in super-critical-fluid chromatography
JPS63177209A (ja) 圧力制御装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 11868358

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS OF RIGHTS PURSUANT TO RULE 112(1) EPC (EPO FORM 1205A DATED 09-04-2014)

122 Ep: pct application non-entry in european phase

Ref document number: 11868358

Country of ref document: EP

Kind code of ref document: A1