Flow correction for back pressure regulated RFF flow modulator

Abstract

To provide a flow correction method for a back pressure regulated RFF flow modulator.SOLUTION: Provided is a method that includes the steps of: when an RFF flow modulator (100) is in a calibration flow condition, directing initial switching flow into the RFF flow modulator in a first direction to an exhaust (116) with pressure regulation; and reducing the initial switching flow to a minimum switching flow where a pressure satisfies a regulation condition. The calibration flow condition includes a primary column flow into the RFF flow modulator from a primary column (102) and a secondary column flow from the RFF flow modulator to a secondary column (106). The operations include determining an adjusted switching flow for the calibration flow condition and determining a switching flow profile based on the adjusted switching flow. When the RFF flow modulator is in an operating flow condition different from the calibration flow condition, the operations include directing an operating switching flow determined based on the switching flow profile in the first direction to the exhaust.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to flow compensation for backpressure regulated RFF flow modulators. [Background technology]

[0002] Gas chromatography (GC) is an analytical technique used to separate and detect chemical components of a sample mixture to determine their presence and / or amount. Fill / flush flow modulators are commonly used in GC and typically operate by collecting (filling) a volume of gas within the modulator channel and then rapidly dispersing (flushing) the gas outside the modulator channel. Reverse fill / flush (RFF) flow modulators flush the modulator channel in the opposite direction to the direction in which the modulator channel is filled. Summary of the Invention [Problem to be solved by the invention]

[0003] The problem to be solved by the present invention is to provide a method (400) that includes, for example but not limited to, "directing an initial switching flow into an RFF flow modulator (100) in a first direction to exhaust (116) using pressure regulation when the RFF flow modulator (100) is in a calibration flow state, and reducing the initial switching flow to a minimum switching flow at which the pressure satisfies the regulation condition." [Means for solving the problem]

[0004] One aspect of the disclosure provides a computer-implemented method of flow compensation for a backpressure-regulated RFF flow modulator. The computer-implemented method is executed by data processing hardware, which causes the data processing hardware to perform operations. If the backfill / flush (RFF) flow modulator is in a calibration flow state, the operations include directing an initial switch flow into the RFF flow modulator in a first direction to exhaust using pressure regulation and reducing the initial switch flow to a minimum switch flow at which the pressure of the RFF flow modulator satisfies an adjustment condition. The calibration flow state includes a primary column flow from the primary column into the RFF flow modulator and a secondary column flow from the RFF flow modulator to a secondary column. The operations include determining an adjusted switch flow for the calibration flow state. The operations further include determining a switch flow profile based on the adjusted switch flow for the calibration flow state. If the RFF flow modulator is in an operational flow state different from the calibration flow state, the operations include directing the operational switch flow in a first direction to exhaust. The operational switching flow is determined based on the switching flow profile.

[0005] Implementations of the present disclosure may include one or more of the following optional features. In some implementations, determining the switching flow profile is based on a plurality of adjusted switching flows determined for a plurality of calibration flow states. In further implementations, the plurality of calibration flow states includes at least a first calibration flow state including a primary column flow and a first secondary column flow, and a second calibration flow state including a second secondary column flow different from the primary column flow and the first secondary column flow. In still further implementations, the first secondary column flow includes a minimum flow for the secondary column, and the second secondary column flow includes a maximum flow for the secondary column. In other further implementations, the plurality of calibration flow states includes a plurality of different primary column flows and a plurality of different secondary column flows. In some examples, the calibration flow state includes a stable temperature.

[0006] In some aspects, decreasing the initial switching flow includes decreasing the switching flow until the pressure of the RFF flow modulator is no longer regulated. Further, gradually increasing the switching flow until the pressure of the RFF flow modulator meets an adjustment condition at a minimum switching flow. In some implementations, the adjustment condition includes a minimum exhaust flow at the exhaust. In some examples, the adjusted switching flow is based on a minimum switching flow, a primary column flow, and a curtain flow.

[0007] The operations may further include determining a fill volume of the RFF flow modulator based on the operational diversion flow and the fill time, and the operations may further include directing the operational diversion flow in a second direction to the secondary column for a flush time, the flush time being determined based on the fill volume.

[0008] Another aspect of the disclosure provides a system. The system includes memory hardware storing instructions that, when executed on data processing hardware in communication with the memory hardware, cause the data processing hardware to perform an operation. If the reverse fill / flush (RFF) flow modulator is in a calibration flow state, the operation includes directing an initial switching flow into the RFF flow modulator in a first direction to exhaust using pressure regulation and reducing the initial switching flow to a minimum switching flow at which the pressure of the RFF flow modulator satisfies a regulation condition. The calibration flow state includes a primary column flow from the primary column into the RFF flow modulator and a secondary column flow from the RFF flow modulator to the secondary column. The operation includes determining an adjusted switching flow for the calibration flow state. The operation further includes determining a switching flow profile based on the adjusted switching flow for the calibration flow state. If the RFF flow modulator is in an operational flow state different from the calibration flow state, the operation includes directing the operational switching flow in a first direction to exhaust. The operational switching flow is determined based on the switching flow profile. This aspect may include one or more of the following optional features.

[0009] In some implementations, determining the switching flow profile is based on a plurality of adjusted switching flows determined for a plurality of calibration flow states. In further implementations, the plurality of calibration flow states includes at least a first calibration flow state including a primary column flow and a first secondary column flow, and a second calibration flow state including a second secondary column flow different from the primary column flow and the first secondary column flow. In still further implementations, the first secondary column flow includes a minimum flow for the secondary column, and the second secondary column flow includes a maximum flow for the secondary column. In other further implementations, the plurality of calibration flow states includes a plurality of different primary column flows and a plurality of different secondary column flows. In some examples, the calibration flow state includes a stable temperature.

[0010] In some embodiments, decreasing the initial switching flow includes decreasing the switching flow until the pressure of the RFF flow modulator is no longer regulated. Further, gradually increasing the switching flow until the pressure of the RFF flow modulator meets an adjustment condition at a minimum switching flow. In some implementations, the adjustment condition includes a minimum exhaust flow at the exhaust. In some examples, the adjusted switching flow is based on a minimum switching flow, a primary column flow, and a curtain flow.

[0011] The operations may further include determining a fill volume of the RFF flow modulator based on the dynamic switch flow and the fill time, and the operations may further include directing the dynamic switch flow in a second direction to the secondary column for a flush time, the flush time being determined based on the fill volume.

[0012] The details of one or more implementations of the disclosure are set forth in the accompanying drawings and the following specification. Other aspects, features, and advantages will be apparent from the description and drawings, and from the claims. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram of a backpressure regulated RFF flow modulator during a filling operation. [Diagram 2]FIG. 1 is a schematic diagram of an RFF flow modulator during a flush operation. [Diagram 3] 1 is a flow chart of an example operational configuration for a flow compensation method for an RFF flow modulator. [Figure 4] 13 is a flow chart of an example operational configuration for another method of flow compensation for an RFF flow modulator. [Diagram 5] FIG. 1 is a schematic diagram of an example computing device that can be used to implement the systems and methods described herein. [Figure 6] 1 is a table containing examples of flow rate errors relative to nominal flow rate calculations for RFF flow modulators. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Like reference numbers in the various drawings indicate like elements.

[0015] Referring now to the figures and example configurations shown herein, a backpressure regulated backfill / flush (RFF) flow modulator 100 includes a primary column 102 that delivers a sample to the RFF flow modulator 100, a sample loop 104 that collects the sample during a fill operation of the RFF flow modulator 100 (FIG. 1), and a secondary column 106 that carries the sample to a subsequent phase of a connected gas chromatography (GC) system during a flush operation of the RFF flow modulator 100 (FIG. 2). The flow from the primary column 102 to the RFF flow modulator 100 may be referred to as the primary column flow (F1). The flow from the secondary column 106 to the GC system may be referred to as the secondary column flow (F2). A pneumatic control module (PCM) 108 is connected to a diverter valve 109 in the RFF flow modulator 100 and controls a diverter flow (F) to direct sample from the primary column 102 to the sample loop 104 during a fill operation and from the sample loop 104 to the secondary column 106 during a flush operation. SW ) is supplied to the switching valve 109.

[0016] A first splitter or tee fitting 110 of the RFF flow modulator 100 fluidly connects to the primary column 102, the secondary column 106, and the sample loop 104. A second splitter or tee fitting 112 of the RFF flow modulator 100 fluidly connects (via the first tee fitting 110) to the primary column 102 and the sample loop 104, the secondary column 106, and the switching valve 109. A third splitter or tee fitting 114 of the RFF flow modulator 100 fluidly connects to the sample loop 104, the switching valve 109, and an exhaust tube or exhaust conduit 116 that provides backpressure regulation for the RFF flow modulator 100. A length of conduit 118 can extend between the first tee fitting 110 and the second tee fitting 112 to space the first tee fitting 110 from the second tee fitting 112. The PCM 108 also controls the flow of the diverter flow (F) through the diverter valve 109 to only one of the second tee fitting 112 and the third tee fitting 114 at a given time. SW )

[0017] 1 and 2, a first end or channel 110a of the first tee fitting 110 is fluidly connected to the primary column 102 for receiving the primary column flow (F1), a second end or channel 110b of the first tee fitting 110 is fluidly connected to an end of the sample loop 104, and a third end or channel 110c of the first tee fitting 110 is fluidly connected to an end of the conduit 118. A first end or channel 112a of the second tee fitting 112 is fluidly connected to the end of the conduit 118 for receiving the switching flow (F SW ), a second end or channel 112b of the second tee fitting 112 is fluidly connected to the end of the conduit 118 opposite the first tee fitting 110, and a third end or channel 112c of the second tee fitting 112 is fluidly connected to the secondary column 106. The pressure at the end or outlet of the secondary column 106 is referred to as the outlet pressure (P OUT The first end or channel 114a of the third tee fitting 114 may be referred to as a diverter flow (F SW), a second end or channel 114b of the third tee fitting 114 is fluidly connected to an exhaust conduit 116, and a third end or channel 114c of the third tee fitting 114 is fluidly connected to the end of the sample loop 104 opposite the first tee fitting 110. The pressure for the RFF flow modulator 100 at the second end 114b of the third tee fitting 114 and / or the exhaust conduit 116 is referred to as the modulator pressure (P MOD ) can be called the modulator pressure (P MOD ) may represent the pressure across the RFF flow modulator 100, assuming constraints within the RFF flow modulator 100 are negligible, and may be regulated by a pressure control means, as described further below.

[0018] During the filling operation (FIG. 1), the switching valve 109 switches the switching flow (F SW ) to the second tee fitting 112. SW ) may exit the RFF flow modulator 100 along the secondary column 106 as the secondary column flow (F2), and the remaining diverted flow (F SW ) flows along the conduit 118 toward the first tee fitting 110 and the sample loop 104. SW ) is part of the curtain flow (F C ) can be called the outlet pressure (P OUT ) is the modulator pressure (P) during the filling operation to draw the secondary column flow (F2) along the secondary column 106. MOD However, the pressure within the RFF flow modulator 100 can be less than the modulator pressure (P MOD ) may be at least slightly higher at the second tee fitting 112 compared to the third tee fitting 114, which is controlled by the exhaust 116, resulting in a curtain flow (F C ) can mix with the primary column flow (F1) and flow toward and through the sample loop 104 and toward the exhaust conduit 116. This is referred to as the load or exhaust flow (F EX ) can be called the switching current (FSW ) is directed into the second tee fitting 112 during the filling operation, resulting in a curtain flow (F C ) prevents the sample in the primary column flow (F1) from flowing to the secondary column 106, and instead, a curtain flow (F C ) and the primary column flow (F1) fills the sample loop 104.

[0019] Therefore, during the filling operation, the curtain flow (F C )teeth, F C =F SW -F2(1) It can be expressed as:

[0020] And the load flow or exhaust flow (F EX )teeth, F EX =F1+F C (2) It can be expressed as:

[0021] As will be explained further below, the filling operation is performed by a curtain flow (F C ) to maximize the amount of sample present in the sample loop 104 while preventing the primary column flow (F1) from flowing to the secondary column 106, and the packing operation maximizes the packing of the sample loop 104 while minimizing sample loss to the exhaust conduit 116. This is because the switching flow (F SW ), more specifically, by controlling the switching flow (F SW ) is accomplished by controlling the time of the filling motion directed to the second tee fitting 112.

[0022] In other words, the switching current (F SW ) feeds the secondary column 106 and prevents leakage of sample from the primary column 102 into the secondary column 106 by diffusion. C) is supplied to the sample volume (volume between the third tee fitting 114 and the first tee fitting 110). The sample volume (volume between the third tee fitting 114 and the first tee fitting 110) must not be overfilled (losing sample) and the filled volume must be known in order to calculate how much to flush the sample volume. The fill volume (time) is determined by the time taken for the primary column flow (F1) and the curtain flow (F C ) and the fill time. Calculating the exact fill volume (time) depends on the exact flow rate.

[0023] During the flushing operation (FIG. 2), the switching valve 109 switches the switching flow (F SW ) to the third tee fitting 114. SW ) can be the same for flush and fill operations. SW ) is part of the exhaust flow (F EX ) exiting the RFF flow modulator 100 along an exhaust conduit 116, and the remaining diverted flow (F SW ) is the injection flow or flushing flow (F FLUSH ) flows along the sample loop 104 and pushes the sample towards the secondary column 106. FLUSH As the primary column flow (F1) pushes the sample towards the secondary column 106, additional sample from the primary column flow (F1) also flows towards the secondary column 106, and the sample and flushing flow (F FLUSH ) along the secondary column 106 from the RFF flow modulator 100 as secondary column flow (F2). OUT ) is the modulator pressure (P MOD ) (e.g., significantly lower). Therefore, the switching current (F SW ) is directed to a third tee fitting 114 during a flush operation to evacuate the sample loop 104 to the secondary column 106 for further analysis using the GC system.

[0024] When the flow rate into the RFF flow modulator 100 during a flush operation is equal to the flow rate out of the RFF flow modulator 100, the flow balance of the RFF flow modulator 100 is: F SW +F1=F2+FEX (3) It can be expressed as:

[0025] Back pressure adjustment is exhaust flow (F EX ), the flushing flow during the flushing operation (F FLUSH )teeth, F FLUSH =F SW -F1-F C =F2-F1(4) It can be expressed as:

[0026] And the secondary column flow (F2) is F2=F FLUSH +F1(5) It can be expressed as:

[0027] In other words, during the flash operation, the switching current (F SW ) is the flow rate (F SW ) to the second tee joint 112) from a loaded state (the switching valve 109 switches the switching flow (F SW ) to the third tee fitting 114. In the injection state, the diverted flow (F SW ) splits at the third tee fitting 114 to form a diverted flow (F SW A portion (a smaller portion) of the diverted flow (F SW ) flushes the sample through the sample loop 104. At the first tee fitting 110, the flushing flow (F FLUSH ) combines with the primary column flow (F1) to feed the secondary column 106 to provide the secondary column flow (F2). This flush or injection flow is referred to as the flushing flow (F FLUSH ), which can be called (F2-F1).

[0028] In order to accurately flush the filled volume, the flow rate must be known accurately. Two major consequences of an inaccurate flush include that a less than complete flush can result in sample loss, and that an over-flushing can result in poor peak shape due to sample from the primary column flow (F1) continuing to the secondary column 106 after the sample loop 104 has been flushed. Furthermore, the time required to perform a flush operation is minimized to allow detection of peaks defined by the GC system, while minimizing the occurrence of shoulders or tails in detected peaks due to additional flow of sample into the GC. The time required to perform a flush operation is determined by the injection time (T INJECT ), as explained further below. INJECT ) is the load time of the fill operation (T LOAD ) is determined based on the exact load time (T LOAD ) and injection time (T INJECT Determining the peak concentration (P) results in more accurate peak detection in the downstream GC system. M ) is the total injection time (T INJECT ) and load time (T LOAD ), where (x) represents the flush factor, factor times the fill volume, and the injection time (T INJECT )teeth,

[0029]

number

[0030] Calculating the timing of filling and flushing the RFF flow modulator 100 requires relatively accurate flow calculations. These calculations depend on the dimensions of the primary column 102 and the secondary column 106. The accuracy of the flow calculations for the columns is limited by the precision and accuracy of the column dimensions. Although the column length can be precisely measured, it is inconvenient and not commonly done. Furthermore, the column inner diameter (ID) is only nominally known and varies within some manufacturing tolerances (to the extent that the actual flow rate can be about 10 percent higher or lower than the calculated flow rate based on the nominal dimensions). The variation in ID, in addition to the approximate column length, can cause the column flow rate to vary by as much as 20 percent higher or lower than that calculated.

[0031] Known systems have imperfections in the calculation of RFF flow modulators. For example, the flow rates for the primary column 102 and the secondary column 106 can be calculated using the Hagen-Poiseuille equation for capillaries, but the calculations are based on nominal dimensions, so the resulting calculated flow rates are somewhat inaccurate. These inaccuracies are enough to make it difficult, if not impossible, to calculate sufficiently accurate fill and flush volumes (times). Although column lengths can be measured accurately (although this is not easy), typically they are not measured accurately (and there is a lack of motivation to measure the lengths of these columns in current systems). For example, the primary column 102 can be shortened or lengthened by a meter or two, while the shorter secondary column 106 (usually cut by the user) may be shortened or lengthened by tens of centimeters or more. It is not realistic to expect a user to cut columns to an accuracy of a few centimeters, and for typical gas chromatography, it is not required. In addition to the length, the ID of the capillary tube also varies within some manufacturing tolerances. These tolerances vary by manufacturer and ID, but all are within a tolerance range of approximately ±0.003 to 0.010 millimeters for columns with internal diameters of 0.100 to 0.320 millimeters. These variations are unknown and not of concern for general gas chromatography, but for pack and flush volumes (times) they can be significant. Table 600 in Figure 6 includes examples of flow rate errors relative to the nominal calculated flow rate.

[0032] For example, curtain flow (F C ) has a rather large effect due to the error in the secondary column flow (F2). A relatively small and usually tolerable error in the secondary column flow (F2) of 5% is 1 milliliter per minute for a secondary column flow (F2) of 20 milliliters per minute. However, the switching flow (F SW This difference in excess or insufficient flow rate from the curtain flow (F C) results in a very large change in the curtain flow (F C ), resulting in a fill volume (time) with an error greater than 100 percent relative to the nominal calculation. If the secondary column flow (F2) is increased by 1 milliliter per minute, the additional flow above the nominal requires flow coming from the primary column 102, and the curtain flow (F C ) becomes zero. This results in leakage of the sample. It is the flow (F EX ), which may be insufficient and result in backpressure regulation failing.

[0033] During the filling (loading) operation, the filling of the sample loop 104 is performed by the primary column flow (F1) and the curtain flow (F C ) (excessive switching flow (F) to prevent sample leakage from the primary column 102 to the secondary column 106 SW )), whereas the flush depends on the primary column flow (F1) and the curtain flow (F C ) is reduced by the total switching current (F SW ). Fill and flush times based on inaccurate flow rates can result in poor quantification (less than complete transfer or overfilling resulting in sample loss from the exhaust conduit 116), sample leakage, and poor peak shape detected by the GC system. Large secondary column flow (F2) fluctuations can lead to curtain flow (F C ) and therefore the packing volume (time). For example, if the secondary column flow (F2) is lower than the nominally calculated flow rate, the curtain flow (F C ) will be excessive, the packing volume will be larger than calculated, and there will be excessive dilution of the sample. If the secondary column flow (F2) is higher than the nominal calculated one, the curtain flow (F C) will become too low (or even zero), and leakage of sample into the secondary column 106 will occur during the fill cycle. Similarly, but to a lesser extent, variations in the primary column flow (F1) will also affect the fill and flush volumes. Therefore, to compensate for variations in the column flow rate relative to the flow rate calculated based on the nominal column dimensions, a switch flow (F SW ) is adjusted.

[0034] Known RFF flow modulators that use a fixed capillary restriction for the exhaust require manual (user-involved) adjustment to account for flow rate variations (due to variations in column and restriction dimensions) to provide relatively accurate fill and flush timing. Similarly, known RFF flow modulators that use backpressure regulation to control exhaust flow require adjustment of the switching flow (manually performed by the user) to account for inaccurate flow rates calculated based on nominal dimensions.

[0035] The implementations herein provide a sufficiently accurate curtain flow (F C ) and relatively precise filling and flush timing, the dimensional variations of the primary column 102 and secondary column 106, as well as the minimum required exhaust flow (F EX To account for variations in the back pressure regulated RFF flow modulator 100 switching flow (F SW ) to the diverter valve 109 during fill and flush operations, as described further below. For example, the PCM 108 includes and / or communicates with data processing hardware 510 (FIG. 5) and memory hardware 520 (FIG. 5). The memory hardware 520 stores instructions that, when executed on the data processing hardware 510, cause the data processing hardware 510 to perform operations. ... SW ) to operate the PCM 108.

[0036] 3 is a flow chart of an example operational configuration for a method 300 of flow compensation for a backpressure regulated RFF flow modulator. Method 300 may be performed, for example, by computing device 500 of FIG. 5. In operation 302, method 300 includes: SW In operation 304, the method 300 obtains the pressure (P MOD ) satisfies the adjustment condition. SW )

[0037] 4 is a flow chart of an example operational configuration for a method 400 of flow compensation for a backpressure regulated RFF flow modulator 100. Method 400 may be performed, for example, by a computing device 500 of FIG. 5 located in or in communication with a PCM 108 in RFF flow modulator 100. In operation 402, when RFF flow modulator 100 is in a flow state, method 400 starts by calculating an initial switch flow (F SW ) in a first direction to pressure regulated exhaust conduit 116. The flow conditions may include a primary column flow (F1) from primary column 102 into RFF flow modulator 100 and a secondary column flow (F2) from RFF flow modulator 100 to secondary column 106. SW ) is the nominal secondary column flow (F2) and curtain flow (F C ) (e.g., about 0.2 milliliters per minute). In operation 404, the method 400 determines the pressure (P MOD ) is the minimum switching current (F SW ) to the switching current (F SW For example, the initial switching flow (F SW ) is the pressure (P MOD ) is no longer regulated (e.g. exhaust flow (F EX ) is no longer present in the exhaust conduit 116.SW ) and the pressure (P MOD ) is the minimum switching current (F SW ) until the adjustment condition at SW The adjustment condition may include gradually increasing the minimum pressure (P MOD ), e.g., minimum levels of exhaust flow (F EX ) (e.g., about 0.1 milliliters per minute) can include a minimum pressure to reach the exhaust conduit 116. Thus, the minimum diverted flow (F SW ) is the sum of the actual secondary column flow (F2), the actual primary column flow (F1), and the minimum exhaust flow (F EX ) may be based on

[0038] In operation 406, the method 400 determines an adjusted diversion flow (F SW For example, the minimum switching flow (F SW ) is calibrated to the actual primary column flow (F1) at the flow condition and the actual secondary column flow (F2) at the flow condition, the adjusted switching flow (F SW ) is the minimum switching current (F SW ), the primary column flow at flow conditions (F1), the secondary column flow at flow conditions (F2), and the desired minimum curtain flow (F C ) is determined based on, for example, about 0.2 milliliters per minute. Thus, in the flow state, the adjusted switching flow (F SW ) is a minimum curtain flow (F) to prevent sample leakage into the secondary column 106 while satisfying pressure regulation requirements and filling the sample loop 104 during the filling operation. C In operation 408, the method 400 determines an adjusted diversion flow (F SW ) under various flow conditions. The switching flow profile is a function of the adjusted switching flow (F SW ) is adapted to be applicable to the RFF flow modulator 100.

[0039] Operations 402, 404, and 406 may be repeated, as necessary, to determine a switching flow profile. That is, these operations may be performed during a calibration procedure for RFF flow modulator 100, such that the switching flow profile is determined based on a number of adjusted switching flows (F SW In some examples, the switching flow profile is based on at least a first adjusted switching flow (F SW ), and a second adjusted switching flow (F SW ). The first and second calibration flow conditions may include the same primary column flow (F1) from primary column 102 into RFF flow modulator 100 and a different secondary column flow (F2) from RFF flow modulator 100 to secondary column 106, such as a minimum secondary column flow (F2) (e.g., about 20 milliliters per minute) and a maximum secondary column flow (F2) (e.g., about 30 milliliters per minute or more, about 35 milliliters per minute or more, etc.). In other words, the switching flow profile includes a plurality of adjusted switching flows (F SW ), the plurality of flow states include a first calibration flow state including a primary column flow (F1) and a first secondary column flow (F2), and a second calibration flow state including a primary column flow (F1) and a second secondary column flow (F2) different from the first secondary column flow (F2). The calibration flow states may include a stable temperature in the RFF flow modulator 100.

[0040] In some examples, the switching flow profile comprises a multi-factor response surface. Thus, the switching flow profile is determined based on results from an array of calibration flow conditions that vary both the primary column flow (F1) and the secondary column flow (F2). That is, the switching flow profile is based on a plurality of calibration flow conditions having a plurality of different primary column flows (F1) and a plurality of different secondary column flows (F2). Thus, the plurality of calibration flow conditions includes at least a first adjusted switching flow (F SW ) and a second adjusted switching flow (F SW), where the first calibration flow state includes a first primary column flow (F1) and a first secondary column flow (F2), and the second calibration flow state includes a different second primary column flow (F1) and a different second secondary column flow (F2).

[0041] Thus, when the switching flow profile or multi-factor response surface is determined, the calibrated RFF flow modulator 100 can be operated to perform fill and flush operations using accurate fill and flush volumes or times. For example, in operation 410, the method 400 may determine the operating switching flow (F SW ) in a first direction to the exhaust conduit 116, thereby forming a curtain flow (F C ) to fill the sample loop 104, where a switching flow (F SW ) is determined based on the switching flow profile. In operation 412, the method 400 determines the operating switching flow (F SW determining a fill volume of the RFF flow modulator 100 based on the fill time of the fill operation and an operational switch flow (F SW ) in a second direction to the secondary column 106. SW ) is the filling operation switching flow (F SW ), and the flush time of the flush operation is determined based on the fill volume to completely and accurately flush the sample in the sample loop 104 into the secondary column 106.

[0042] In other words, the automatic procedure is SW ) is separated by a secondary column flow (F2) and a small (approximately 0.2 milliliters per minute) curtain flow (F C ) to provide a switching current (F SW ) to account for flow rate variations from nominal. The procedure involves setting the flow conditions to typical flow conditions at stable or consistent temperature conditions, and adjusting the nominally calculated diversion flow (F2) to account for possible high secondary column flows (F3). SW) to a reasonable level and then increasing the pressure (P MOD ) is no longer regulated. SW ) downward and then back up until the point where pressure regulation is just sufficient. At this point, the switching flow (F SW ) plus the primary column flow (F1) may just be enough to feed the secondary column 106, with the excess going to the exhaust conduit 116 being sufficient for pressure regulation. Then, the value of the diversion flow (F SW ) is the new switching current value (F SW ), the primary column flow (F1) and the desired curtain flow (F C ) (typically 0.2 milliliters per minute). This can be done with a minimum secondary column flow (F2) allowed (e.g., about 20 milliliters per minute), and a maximum (e.g., about 30 to 35 milliliters per minute). A switching flow profile, such as a linear equation with slope and offset, is added to the switching flow (F) determined with sufficient adjustment points for each flow condition. SW ) are established from these two points. The slope and offset are determined by the different secondary column flows (F2) and the adjusted switching flow (F SW ), which is then used to determine the primary column flow (F1) and curtain flow (F C ) based on the required switching current (F SW ) is used to calculate the required exhaust flow (F EX ) may not be known. Note that the procedure can be done all under software control. This procedure may be performed when either or both of the primary column 102 and secondary column 106 are changed and / or periodically over time. Optionally, when the primary column 102 and secondary column 106 remain consistent between fill and flush operations, the calibration process may not need to be repeated.

[0043] Additionally, more complex procedures may be implemented when the minimum flow into the exhaust conduit 116 is not small or is not known. For example, a regulated diversion flow (F SW ) may be determined several times with different primary column flows (F1) and secondary column flows (F2). Factorials of two or three of the flow rates may be used. For each flow combination (factorial processing), a calibration process is performed to determine the adjusted switching flow (F SW ) can then be performed to determine the switching flow (F SW ) is regressed against the nominal, calculated flow rates used to generate the response surface. The regression results are SW These corrected flow rates are then calculated based on the flow balance equation to obtain the desired primary column flow (F1) and secondary column flow (F2) as well as the curtain flow (F C ) for the appropriate switching current (F SW ) can be used to calculate the flow rate (the minimum flow required for backpressure regulation). The constant of the regression is for the minimum flow required for backpressure regulation. If this flow rate is variable across the conditions being tested, it may have to be included as a variable and additional treatments (conditions) added for that.

[0044] In other words, the implementation is such that the switching flow (F SW ) for automatic adjustment. These implementations do not require user input in the calibration of the RFF flow modulator 100. Additionally, the implementations herein do not require precise measurement of columns and / or other small constraints within the RFF manifold. The "fill" procedure includes a primary column flow (F1), a curtain flow (F C ), the secondary column flow (F2), and the switching flow (F SW In some implementations, the variation in the secondary column flow (F2) can be calculated based on the curtain flow (F C ) (and subsequently the fill volume time). As mentioned above, if the fill volume is incorrect, the flush procedure is also affected. Therefore, the switching flow (FSW ) is the proper curtain flow (F C ) can be automatically adjusted to provide a switching flow (F SW ) is set to a high level, and then the pressure (P MOD ) is gradually decreased until it is no longer regulated (called the zero point). Then, at the zero point, the curtain flow (F C ) is the switching current (F SW ) may be added.

[0045] 5 is a schematic diagram of an example computing device 500 that may be used to implement the systems and methods described herein. Computing device 500 is intended to represent various forms of digital computers, such as laptops, desktops, workstations, personal digital assistants, servers, blade servers, mainframes, and other suitable computers. The components shown, their connections and relationships, and their functions are intended to be exemplary only and are not intended to limit the implementation of the invention described and / or claimed herein.

[0046] Computing device 500 includes a processor 510, a memory 520, a storage device 530, a high-speed interface / controller 540 that connects to memory 520 and a high-speed expansion port 550, and a low-speed interface / controller 560 that connects to a low-speed bus 570 and storage device 530. Each of components 510, 520, 530, 540, 550, and 560 may be interconnected using various buses and mounted on a common motherboard or otherwise as desired. Processor 510 can process instructions for execution within computing device 500, including instructions stored in memory 520 or on storage device 530 to display graphical information for a graphical user interface (GUI) on an external input / output device, such as a display 580 coupled to high-speed interface 540. In other implementations, multiple processors and / or multiple buses may be used, along with multiple memories and multiple types of memories, as desired. Also, multiple computing devices 500 may be connected, each providing a portion of the required operations (eg, as a bank of servers, a group of blade servers, or a multi-processor system).

[0047] The memory 520 stores information non-transiently within the computing device 500. The memory 520 may be a computer-readable medium, a volatile memory unit, or a non-volatile memory unit. The non-transient memory 520 may be a physical device used to temporarily or permanently store programs (e.g., sequences of instructions) or data (e.g., program state information) for use by the computing device 500. Examples of non-volatile memory include, but are not limited to, flash memory and read-only memory (ROM) / programmable read-only memory (PROM) / erasable programmable read-only memory (EPROM) / electronically erasable programmable read-only memory (EEPROM) (e.g., typically used for firmware such as boot programs). Examples of volatile memory include, but are not limited to, random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), phase change memory (PCM), as well as disks or tapes.

[0048] The storage device 530 can provide mass storage for the computing device 500. In some implementations, the storage device 530 is a computer-readable medium. In various different implementations, the storage device 530 may be a floppy disk device, a hard disk device, an optical disk device, or an array of devices including a tape device, a flash memory or other similar solid-state memory device, or a device in a storage area network or other configuration. In additional implementations, the computer program product is tangibly embodied in an information carrier. The computer program product includes instructions that, when executed, perform one or more methods, such as those described above. The information carrier is a computer-readable or machine-readable medium, such as the memory 520, the storage device 530, or a memory on the processor 510.

[0049] The high-speed controller 540 manages bandwidth-intensive operations for the computing device 500, while the low-speed controller 560 manages less bandwidth-intensive operations. Such an assignment of roles is merely exemplary. In some implementations, the high-speed controller 540 is coupled to the memory 520, the display 580 (e.g., via a graphics processor or accelerator), and the high-speed expansion port 550, which can accept various expansion cards (not shown). In some implementations, the low-speed controller 560 is coupled to the storage device 530 and the low-speed expansion port 590. The low-speed expansion port 590, which may include various communication ports (e.g., USB, Bluetooth, Ethernet, wireless Ethernet), may be coupled, for example, via a network adapter, to one or more input / output devices, such as a keyboard, a pointing device, a scanner, or a networking device such as a switch or router.

[0050] The computing device 500 may be implemented in a number of different forms, as shown in the figure: for example, it may be implemented as a standard server 500a, or multiple times among a group of such servers 500a, as a laptop computer 500b, or as part of a rack server system 500c.

[0051] Various implementations of the systems and techniques described herein may be realized in digital electronic and / or optical circuitry, integrated circuits, specially designed ASICs (application specific integrated circuits), computer hardware, firmware, software, and / or combinations thereof. These various implementations may include implementations in one or more computer programs executable and / or interpretable on a programmable system including at least one programmable processor, which may be special purpose or general purpose coupled to receive data and instructions from and transmit data and instructions to a storage system, at least one input device, and at least one output device.

[0052] These computer programs (also known as programs, software, software applications, or codes) contain machine instructions for a programmable processor and can be implemented in high-level procedural and / or object-oriented programming languages ​​and / or assembly / machine languages. As used herein, the terms "machine-readable medium" and "computer-readable medium" refer to any computer program product, non-transitory computer-readable medium, apparatus and / or device (e.g., magnetic disk, optical disk, memory, programmable logic device (PLD)) used to provide machine instructions and / or data to a programmable processor, including a machine-readable medium that receives the machine instructions as a machine-readable signal. The term "machine-readable signal" refers to any signal used to provide machine instructions and / or data to a programmable processor.

[0053] A software application (i.e., a software resource) may refer to computer software that causes a computing device to perform a task. In some examples, a software application may be referred to as an "application," an "app," or a "program." Examples of applications include, but are not limited to, system diagnostic applications, system management applications, system maintenance applications, word processing applications, spreadsheet applications, messaging applications, media streaming applications, social networking applications, and gaming applications.

[0054] The processes and logic flows described herein may be executed by one or more programmable processors, also referred to as data processing hardware, which execute one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows may also be executed by special purpose logic circuitry, for example, an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit). Processors suitable for executing computer programs include, by way of example, both general purpose and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor receives instructions and data from a read-only memory, or a random access memory, or both. The essential elements of a computer are a processor for executing instructions, and one or more memory devices for storing instructions and data. Generally, a computer also includes one or more mass storage devices, for example, magnetic disks, magneto-optical disks, or optical disks, for storing data, or is operably coupled to receive data from them, or operably coupled to transmit data to them, or both. However, a computer need not have such devices. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, including, by way of example, semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices, magnetic disks, e.g., internal hard disks or removable disks, magneto-optical disks, and CD ROM and DVD-ROM disks. The processor and memory may be supplemented by, or incorporated in, special purpose logic circuitry.

[0055] To provide for user interaction, one or more aspects of the present disclosure may be implemented on a computer having a display device, e.g., a CRT (cathode ray tube), LCD (liquid crystal display) monitor, or touch screen, for displaying information to the user, and optionally a keyboard and pointing device, e.g., a mouse or trackball, by which the user can provide input to the computer. Other types of devices may also be used to provide for user interaction, e.g., feedback provided to the user may be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback, and input from the user may be received in any form, including acoustic, speech, or tactile input. In addition, the computer may interact with the user by sending documents to and receiving documents from a device used by the user, e.g., by sending a web page to a web browser on the user's client device in response to a request received from the web browser.

[0056] Although several implementations have been described, it will be understood that various modifications may be made without departing from the spirit and scope of the present disclosure. Accordingly, other implementations are within the scope of the following claims.

Claims

1. A method (400) performed by a computer, wherein the method (400) is performed by data processing hardware (510), the data processing hardware (510) includes: When the back-packing / flash (RFF) flow modulator (100) is in a calibration flow state including a primary column flow from the primary column (102) into the RFF flow modulator (100) and a secondary column flow from the RFF flow modulator (100) to the secondary column (106), the initial switching flow into the RFF flow modulator (100) is directed towards the exhaust (116) in a first direction using back pressure adjustment of the exhaust flow in the exhaust (116), and the initial switching flow is reduced to a minimum switching flow that satisfies the back pressure adjustment conditions of the exhaust flow in the exhaust (116), A step of determining a regulated switching flow for the calibration flow state, wherein the regulated switching flow is configured to provide a minimum curtain flow between the primary column (102) and the secondary column (106), A step of determining a switching flow profile based on multiple regulated switching flows determined for multiple calibration flow states, For an operating flow state having at least one of the primary column flow and the secondary column flow, which is different from the calibration flow state, the step of determining the operating switching flow based on the switching flow profile, A method (400) for causing the RFF flow modulator (100) to perform an operation including the step of directing the operation switching flow toward the exhaust (116) in the first direction when the RFF flow modulator (100) is in the operation flow state.

2. The aforementioned multiple calibration flow states are, A first calibration flow state including the primary column flow and the first secondary column flow, A second calibration flow state including a second secondary column flow that is different from the primary column flow and the first secondary column flow, The method according to claim 1 (400), including the method according to claim 1.

3. The first secondary column flow includes a minimum flow for the secondary column (106), The second secondary column flow includes the maximum flow for the secondary column (106). The method according to claim 2 (400).

4. The method according to claim 1 (400), wherein the plurality of calibration flow states include a plurality of different primary column flows and a plurality of different secondary column flows.

5. The method according to any one of claims 1 to 4 (400), wherein the plurality of calibration flow states include a stable temperature.

6. The step of reducing the initial switching flow is, The switching flow is reduced until the pressure of the RFF flow modulator (100) is no longer regulated, The RFF flow modulator (100) gradually increases the switching flow until the pressure satisfies the conditions for adjusting the back pressure of the exhaust flow in the exhaust (116) at the minimum switching flow. The method according to any one of claims 1 to 4 (400), including the method described above.

7. The method according to any one of claims 1 to 4 (400), wherein the conditions for adjusting the back pressure of the exhaust flow in the exhaust (116) include a minimum exhaust flow in the exhaust (116).

8. The method according to any one of claims 1 to 4 (400), wherein the adjusted switching flow is based on the minimum switching flow, the primary column flow, and the minimum curtain flow.

9. The aforementioned operation is, The steps include determining the filling volume of the RFF flow modulator (100) based on the operation switching flow and filling time, The method according to any one of claims 1 to 4 (400), further comprising the step of directing the operation switching flow toward the secondary column (106) in a second direction for a flash time, wherein the flash time is determined based on the packing volume.

10. In the system, the system is Data processing hardware (510) and The system includes a data processing hardware (510) and a memory hardware (520) that communicates with the data processing hardware (510) and stores instructions, and when the instructions are executed on the data processing hardware (510), the system communicates to the data processing hardware (510). When the back-packing / flash (RFF) flow modulator (100) is in a calibration flow state including a primary column flow from the primary column (102) into the RFF flow modulator (100) and a secondary column flow from the RFF flow modulator (100) to the secondary column (106), the initial switching flow into the RFF flow modulator (100) is directed towards the exhaust (116) in a first direction using back pressure adjustment of the exhaust flow in the exhaust (116), and the pressure in the RFF flow modulator (100) is reduced to the minimum switching flow that satisfies the back pressure adjustment conditions of the exhaust flow in the exhaust (116), Determining a regulated switching flow for the calibration flow state, wherein the regulated switching flow is configured to provide a minimum curtain flow between the primary column (102) and the secondary column (106), Determining a switching flow profile based on multiple regulated switching flows determined for multiple calibration flow states, For an operating flow state having at least one of the primary column flow and the secondary column flow, which is different from the calibration flow state, the operating switching flow is determined based on the switching flow profile, A system that causes the RFF flow modulator (100) to perform an operation including directing the operation switching flow toward the exhaust (116) in the first direction when the RFF flow modulator (100) is in the operation flow state.

11. The aforementioned multiple calibration flow states are, A first calibration flow state including the primary column flow and the first secondary column flow, A second calibration flow state including a second secondary column flow that is different from the primary column flow and the first secondary column flow, The system according to claim 10, including the following:

12. The first secondary column flow includes a minimum flow for the secondary column (106), The second secondary column flow includes the maximum flow for the secondary column (106). The system according to claim 11.

13. The system according to claim 10, wherein the plurality of calibration flow states include a plurality of different primary column flows and a plurality of different secondary column flows.

14. The system according to any one of claims 10 to 13, wherein the plurality of calibration flow states include a stable temperature.

15. Reducing the initial switching flow means that The switching flow is reduced until the pressure of the RFF flow modulator (100) is no longer regulated, The RFF flow modulator (100) gradually increases the switching flow until the pressure satisfies the conditions for adjusting the back pressure of the exhaust flow in the exhaust (116) at the minimum switching flow. A system according to any one of claims 10 to 13, including the system described above.

16. The system according to any one of claims 10 to 13, wherein the conditions for adjusting the back pressure of the exhaust flow in the exhaust (116) include a minimum exhaust flow in the exhaust (116).

17. The system according to any one of claims 10 to 13, wherein the regulated switching flow is based on the minimum switching flow, the primary column flow, and the minimum curtain flow.

18. The aforementioned operation is, The filling volume of the RFF flow modulator (100) is determined based on the operation switching flow and filling time, The system according to any one of claims 10 to 13, further comprising directing the operation switching flow toward the secondary column (106) in a second direction during a flash time, wherein the flash time is determined based on the packing volume.

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