GB2290283A - Rotary injection valve - Google Patents

Description

2290283 ROTARY INJECTION VALVE This invention relates to methods and

apparatus for fluid injection. and, more particularly, to the injection of a sample fluid volume in chromatography by means of a rotating valve assembly.

Rotary sampling valves can be operated to receive and then deliver a sample volume into one or more fluid streams in a fluid flow system. The sample volume is contained in a "loop", such as an attached length of tubing or an etched groove in a valve rotor. The sample volume is injected by rotation of the valve rotor so that the loop becomes part of the fluid stream. As a result, the sample is injected into the fluid stream.

Rotary sampling valves are used for gas and liquid sampling in highresolution chromatography, wherein the valves can be coupled directly to a chromatographic column or in series with a packed-column direct inlet or a capillary split inlet to deliver a sample volume. One example of a rotary valve, as shown in Figures 1A - 1 B, is available from the Valco Corporation (Houston, Texas). Such a valve (20) incorporates internal channels (22, 23, 24) that are positionable between adjacent peripheral valve ports (31, 32, 35, 36) via rotation of a moveable rotor (indicated schematically by an arrow), which can be manipulated to connect two or more peripheral ports.

As shown in Figure 1A, the valve rotor may be rotated to a sample load position so as to load a sample volume from a sample line (S) into one of the internal channels (23) with excess sample removed by a waste line (M. As shown in Figure 1 B, the rotor is then rotated in the opposite direction to a sample injection position, wherein the sample volume may be delivered by pressure from a pump (P) into a column (C). The extent of the time p=..-:,od defined by the 2 presence of a sample-filled channel in fluid communication with the two peripheral ports at the sample delivery position is known as the residence time. Typically, the rotor is keyed and the channels are symmetrically arranged so that only two positions of the rotor can be established, and if the orientation of the valve is to be changed, then the rotor must reverse direction. Thus, to return to the sample load position (Figure 1A), the rotor must reverse direction again.

Conventional sampling valves are limited to the delivery of sample volumes that are higher than would be desirable in certain applications.

The present invention seeks to provide improved fluid injection.

According to a n aspect of the present invention there is provided a rotary injection valve, comprising a rotor including an exterior surface and a slice on the exterior surface; and a housing including a central bore for receiving the rotor and first and second pairs of peripheral ports spaced about a central axis; wherein the rotor is positionable in the bore by relative motion between the housing and the rotor in a sustained motion about the central axis from an initial configuration, wherein the slice can be aligned with the second pair of peripheral ports so as to effect fluid communication therebetween, and can pass an intermediate position wherein the slice is aligned with the first pair of peripheral ports so as to effect momentary fluid communication therebetween.

According to another aspect of the present invention there is provided a rotary injection valve, comprising a rotor including an exterior surface and first and second slices on the exterior surface; and a housing including a central bore for receiving the rotor and first and second pairs of peripheral ports spaced about a central axis; wherein the rotor is positionable in the bore by relative motion between the housing and the rotor in a sustained motion about the central axis from an initial configuration, wherein the first slice can be aligned with the first pair of peripheral ports so as to effect fluid communication therebetween andthe second slice can be aligned with the second pair of peripheral- portsso as 3 to effect f Wid communication therebetween, the rotor being able to pass an intermediate position wherein the first slice is aligned with the second pair of peripheral ports so as to effect momentary fluid communication therebetween.

According to another aspect of the present invention there is provided a sample analysis system for analysis of the constituent components of a sample fluid present in a sample inject line, comprising a rotor including an exterior surface and first and second slices on the exterior surface; a housing including a central bore for receiving the rotor and first and second pairs of peripheral ports spaced about a central axis, the first pair of peripheral ports being operatively connected to the sample inject line and a waste line, and the second pair of peripheral ports being operatively connected to a pump line and a column line; wherein the rotor is positionable in the bore by relative motion between the housing and the rotor in a sustained motion about the central axis from an initial configuration, wherein the first slice can be aligned with the first pair of peripheral ports so as to effect fluid communication between the sample line and waste line for capture of a predetermined sample fluid volume, and the second slice can be aligned with the second pair of peripheral ports so as to effect fluid communication between the pump line and column line, the rotor being able to pass an intermediate position wherein the first slice is aligned with the second pair of peripheral ports so as to effect momentary fluid communication therebetween for delivery of the sample volume to the column line and thereafter to assume a final position, wherein the first slice is aligned with the first pair of peripheral ports so as to effect fluid communication between the sample line and waste line and the second slice is aligned with the second pair of peripheral ports so as to effect fluid communication between the pump line and column line; a mobile phase source operatively connected to the pump line for supplying pressurized mobile phase thereto; and a sample analyzer operatively connected to the column line for receiving the sample volume.

4 According to another aspect of the present invention there is provided a method of accomplishing chromatographic separation and detection of constituent components of a sample fluid present in a sample inject line, comprising the steps of providing a high speed injection valve comprising a rotor including an exterior surface and first and second slices on the exterior surface and a housing including a central bore for receiving the rotor and first and second pairs of peripheral ports spaced about a central axis; connecting the first pair of peripheral ports to the sample inject line and a waste line. and the second pair of peripheral ports to a pump line and a column line; supplying a pressurized mobile phase to the pump line; positioning the rotor and the housing in an initial configuration, wherein the first slice is aligned with the first pair of peripheral ports so as to effect fluid communication between the sample line and waste line for capture of a predetermined sample fluid volume, and the second slice is aligned with the second pair of peripheral ports so as to effect fluid communication between the pump line and column line; effecting unidirectional sustained relative motion of the rotor and the housing about the central axis from the initial configuration to pass an intermediate configuration. wherein the first slice is aligned with the second pair of peripheral ports so as to effect momentary fluid communication therebetween for delivery of the sample volume to the column line; positioning the rotor and the housing in a final configuration, wherein the first slice is aligned with the first pair of peripheral ports s-- as to effect fluid communication between the sample line and waste line, and the second slice is aligned with the second pair of peripheral ports so as to effee. fluid communication between the pump line and column line; and analyzing the sample volume in the column line at a sample analyzer.

The preferred embodiments can provide simple and inexpensive apparatus for delivering ultra small (picoliter or nanoliter) volumes of a sample fluid into a fluid flow for use, for example, in high-resolution chromatography.

In a first preferred embodiment of the present invention, a high-speed rotary injection valve may be constructed to include a rotor having an exterior surface and a first slice on the exterior surface, and a housing defining a central bore for receiving the rotor. The housing includes first and second pairs of peripheral ports spaced about a central axis. The rotor is positionable in the bore according to relative motion between the housing and the rotor in a unidirectional sustained motion about the central axis from an initial configuration, wherein the first slice is aligned with the second pair of peripheral ports so as to effect fluid communication therebetween, to pass an intermediate configuration, wherein the first slice is aligned with the first pair of peripheral ports s'o as to effect momentary fluid communication therebetween.

In a second preferred embodiment of the present invention, a high-speed rotary injection valve may be constructed to include a rotor having a exterior surface and first and second slices on the exterior surface. The housing defines a central bore for receiving the rotor and has first and second pairs of peripheral 6 ports spaced about a central axis. The rotor is positionable in the bore according to relative motion between the housing and the rotor in a unidirectional sustained motion about the central axis from an initial configuration, wherein the first slice is aligned with the first pair of peripheral ports so as to effect fluid communication therebetween and the second slice is aligned with the second pair of peripheral ports so as to effect fluid communication therebetween, to pass an intermediate configuration, wherein the first slice is aligned with the second pair of peripheral ports so as to effect momentary fluid communication therebetween.

The aforementioned embodiments of a high-speed rotary injection valve are preferably employed in a sample analysis system for analysis of the constituent components of a sample fluid present in a sample inject line.

Because a conventional rotary sampling valve effects sample injection by forward rotation from a sample load position to a sample delivery position and reverse rotation to the sample load position, any reduction in the residence time at the sample delivery position is limited by the inertia of the rotor and an inability of the driving mechanism to effectively switch the rotor to and from the sample delivery position. In contrast, the preferred embodiments of a high-speed rotary injection valve operate by sustained unidirectional relative motion so as to pass a sample delivery position at high speed without reversal. and therefore do not suffer the drawbacks of the conventional approach. The preferred embodiments offer a reduction in residence time over that of conventional rotary sampling valves and accordingly the delivered portion of the sample volume is ultra small (ranging between approximately 20 picoliters to 20 nanoliters). Such portions are considerably less than the volume of sample fluid typically delivered by a rotary sample valve of the prior art.

An embodiment of the present invention is described below, by way of example only, with reference to the accompanying drawings, in which:

0 7 Figure 1A is a simplified schematic representation of a rotary injection valve constructed according to the prior art, with the valve shown in a sample load position.

Figure 1 B is a simplified schematic representation of the rotary injection valve of Figure 1A, with the valve shown in a sample inject position.

Figure 2 is a simplified schematic representation of a chromatographic system employing a high speed rotary injection valve constructed according toa preferred embodiment.

Figure 3 is an exploded perspective view of a preferred embodiment of a high speed rotary injection valve constructed Figures 4A4D are simplified schematic representations of a first preferred embodiment of the high speed rotary injection valve of Figure 3, illustrating the sequential configurations of a sample delivery sequence.

Figures 5A-5D are simplified schematic representations of a second preferred embodiment of the high speed rotary injection valve of Figure 3, illustrating the sequential configurations of a sample delivery sequence.

The described valve will rind useful application in a variety of fluid handling systems that benefit from the delivery of an ultra small volume of a sample fluid into a fluid flow. Such systems are commonly employed in a wide variety of applications, such as sample purification, chemical analysis, clinical assay, industrial processing, water purification, reagent dispensing, manual and automated solid phase extraction, supercritical fluid extraction, stopped-flow spectrophotometry, clinical analysis, automated protein or nucleic acid sequencing, and solid phase protein or nucleic acid synthesis. FurIther examples that are 8 particularly benefited by use of the described valve. include high pressure liquid or gas chromatography and flow-injection analysis.

Accordingly, Figure 2 illustrates a sample analysis system (110) contemplated for accomplishing a chromatographic separation and detection of the various components in a sample fluid provided on a sample inject line (S) to a high speed rotary injection valve (hereinafter valve assembly (112)).

The valve assembly (112) includes a rotor (112R) located in a central bore defined by a housing (1121-1). The rotor (112R) and housing (1121-1) are subject to relative movement about a central axis (1 12X). The housing (112H) includes a first pair (121) of peripheral ports (described hereinbelow with respect to Figure 3) that allow fluid communication between the central bore and a sample inject line (S) and a waste line (W), and a second pair (122) of peripheral ports that allow fluid communication between the central bore and a pump line (P) and a column line (C). The pump line (P) is operatively connected to a mobile phase source (114) and the column line is operatively connected to a sample analyzer (116) preferably in the form of an optional separation device (118) and a detector (120).

The illustrated sample analysis system (110) is contemplated for use as a gas or liquid chromatograph and hence the separation device (118) is operated for separating the constituent components of the de';vered sample volume, and may include an open tubular or open capillary silica column. The detector (120) may then be used to detect the separated components of interest. Modifications and additional components (not shown) may be included as known in the art. For example, it is contemplated that alternative embodiments of the sample analysis system (110) may be constructed to function as another type of chromatograph such as a multidimensional chromatographic analysis system, or a flow injection analysis system or a capillary electrophcresis syslem.

As shown in Figure 3, the rotor (1 12R) is retained in a housing (132) by a 9 sleeve (134) attachable to a housing face (136). The housing (132) preferably comprises four peripheral ports (138) which are grouped in first and second peripheral port pairs (121, 122) located on the periphery of the housing. Preferably the ports (138) are provided in the form of a sample inject line port (138S) and waste line port (138W) in the first peripheral port pair (121), and a pump line port (138P) and column line port (138C) in the second peripheral port pair (122).

When the rotor (1 12R) is inserted in a bore (150) in the housing (132), each port (138) is capable of sequential fluid communication with a selected one of first and second slices (142, 144) on the exterior surface of the rotor (1 12R) depending upon the orientation of the valve rotor (1 12R) with respect to the housing (132). Preferably, each pair (121, 122) of peripheral ports has dimensions and spacing such that when a selected slice is aligned with a selected one of the first and second pairs, the selected slice completes a path for fluid communication between the two ports in the selected pair.

The rotor (112R) includes a drive face (152), an end face (151), and a lateral face (153). The rotor (112R) is sized such that the lateral face (153) maintains close physical contact with the housing (132) when the rotor (112R) is engaged in the bore (150). The sleeve (134) covers the end face (151) when attached to the housing face (136) by suitable means (not shown) to enclose and thus retain the rotor (1 12R) in the housing (132).

With the sleeve (134) thus limiting axial movement of the rotor (1 12R), the rotor and housing may be subjected to relative motion about a central axis (1 12X) by means of a relative motion driver (170). It is preferred that there be no axial deviation in the path of the slices (142, 144) as the rotor and housing undergo relative motion. Preferably, the housing (112H) is held stationary and the rotor (112R) is subject to selectable angular rotation within the bore (150) about the central axis (1 12X) by the rotor driver (170). Alternatively, the relative motion driver (170) may be constructed as knovin in the art to effect movement of the housing (132) while the rotor (1 12R) is held stationary; a still further altemative of the relative motion driver is contemplated as effecting rotation of both the housing (132) and rotor (1 12R) in combination.

The relative motion of the rotor (1 12R) and housing (132) about the central axis (1 12X) may be limited to a predetermined amount by an appropriate relative motion limiter. In the preferred embodiments described hereinbelow, a stop pin (154) fixed at the lateral face (153) cooperatively travels in a recess (162) in the sleeve (134) as the rotor (112R) and the housing (132) undergo relative motion about the central axis (1 12X). Access to the stop pin (154) is provided at a recess window (164). Controlled insertion of an engaging means (shown as an actuated cam (66) in Figures 4-5) into the window (164) will thereby limit the travel of the stop pin (154) and thus limit the extent of relative motion. Preferably, the rotor driver (170) is provided to engage the drive face (152) by known means and to rotate the rotor (1 12R) while the housing (132) is held stationary. The rotor driver (170) includes an electronic or pneumatic actuator capable of rapid rotation of the rotor (112R). However, the rotor driver (170) may incorporate a relative motion limiter internally such that the rotor driver can precisely initiate. maintain, and arrest the rotation of the rotor (1 12R). In such an instance, the stop pin (154), cam (166), and window (164) may be omitted.

The slices (142, 144) can be created in the rotor surface by known mechanical andlor chemical methods, such as etching, drilling, molding, or stamping. It is preferred that the slices have a size and depth appropriate to the predetermined sample volume that is desired for delivery, as will be described below. While the preferred slices include semi-circular, square, circular, or rectangular etched cuts on the lateral face (153), it is contemplated that an alternative embodiment of the valve assembly may be constructed to include such cuts on the end face (151). Such an alternative design would then require the ports (138) and associated apparatus to be respectively provided on the front face (135) 1 of the sleeve (134) so as to communicate through the body of the sleeve to the end face (151).

The components of the valve assembly (112) can be fabricated from a variety of materials. It is pr eferred that the rotor (112R) and housing (132) be formed of materials, such as stainless steel andlor an organic polymer, that are inert to the fluids carried by the valve. Exemplary inert polymers are polyimides, aramid polymels, acetal resins, and poly(tetrafluoroethylene) such as available from the DuPont Company (Wilmington, Del.) under the tradenames Vespel, Keviar, Delrin, and Teflon, respectively; and poly(chlorotrifluoroethylene), such as available from the 3M Company (Newark, N.J.) under the tradename Kel-F.

As shown in Figures 4A, 4B, 4C, and 4D, a first preferred embodiment (1 12A) of the valve assembly (112) may be operated to perform a sample delivery cycle whereby a selected volume of a sample fluid may be injected into the column line (C) for delivery to the analyzer (116) of Figure 2. Figure 4A illustrates the first preferred embodiment (1 12A) in an initial configuration adapted for sample loading. The rotor (1 12R) is positioned such that the first slice (144) communicates with the sample inject port (1 38S) and the waste line port (1 38M. and the second slice (142) communicates with the pump line port (138P) and the column line port (138C). A sample fluid stream is introduced into the sample inject line (S) and through the sample inject port (138S) so as to accumulate sample fluid (F) in the first slice (142). (Preferably, as shown in Figure 3, the sample fluid is introduced into the sample inject line (S) via a syringe (184)). Excess sample fluid (F) is allowed to pass into the waste line port (138M and exits the valve assembly via the waste line (M. A mobile phase fluid is introduced under regulated pressure into the pump line (P) and through the pump line port (138P) to the second slice (144). The mobile phase fluid may then flow into the column line port (138C) and into a column (186). The rotor driver (170) is actuated and the arresting cam (66) may be retracted (not necessarily in that order) so as to initiate high speed relative 12 motion of the rotor (1 12R) with respect to the housing (132).

Figure 4B illustrates the first preferred embodiment (1 12A) in a subsequent first intermediate configuration adapted for sample injection. Upon an accumulated rotation of approximately 120 degrees, the first slice (142) passes under (and momentarily communicates with) the pump line port (138P) and the column line port (138C). The second slice (142), which now contains a trapped volume of mobile phase fluid under pressure, is located at a position intermediate between the first and second pairs of peripheral ports and hence is not in communication with any of the peripheral ports. A predetermined volume of sample fluid (F), previously trapped in the first slice, is thereby subject to the flow of the mobile phase fluid from the pump line (P) through the first slice (142) into the column line (C). Depending upon, among other things, the residence time that the first slice (142) is in fluid communication with the pump line port (13812) and the column line port (138C), the angular velocity of the rotor (1 12R), the linear velocity of the sample fluid flow into the column line (C), and the volume of sample contained in the first slice (142), a predetermined portion of the trapped sample volume is transferred to the column (186). Because the relative motion of the rotor (1 12R) with respect to the housing (132) is sustained and unidirectional, the first slice (142) is moved away from the pump line port (182P) until sealed by the interior of the housing (132). The first slice (142) thereafter carries a pressurized mixture of mobile phase fluid and any non-injected portion of the sample volume.

Figure 4C illustrates the first preferred embodiment (112A) in a second intermediate configuration. Upon an accumulated rotation of approximately 240 degrees, the first slice (142) is located at a position intermediate between the first and second pairs of peripheral ports and hence is not in communication with any of the peripheral ports. The second slice (144), which still contains a trapped volume of mobile phase fluid under pressure, momentarily becomes in fluid communication with the sample in. ect line port (138P) and the waste line port 1 13 (138C). The sample inject line (138S) and waste line(138W) are at or near atmospheric pressure and therefore no sample fluid is transferred to the second slice (144). The mobile phase fluid trapped in the second slice (144) is vented to the waste line (138W). The arresting cam (66) is returned to its initial position such that the relative motion of the rotor (1 12R) will soon be arrested.

Figure D illustrates the first preferred embodiment (1 12A) in a final configuration adapted for purging the first and second slices (142, 144) and for resetting the valve assembly. The rotation of the rotor (1 12R) is arrested upon the contact of the stop pin (154) with the arresting cam (66). The rotor (112 R) is thus positioned such that the first slice (142) again communicates with the sample inject port (138S) and the waste line port (13SW), and the second slice (142) again communicates with the pump line port (1 3SP) and the column line port (1 38C). The samplelmobile phase fluid mixture that remains in the first slice (142) under pressure is vented from the first slice through the waste line port (138W) and the waste line (W). The regulated flow of mobile phase fluid may again be passed into the pump line (P) and pump line port (138P) through the second slice (144) and the column line port (138C) into the column (186). The valve assembly (112A) is thereby reset and ready for another cycle of sample loading and delivery.

The foregoing sample delivery sequence described with reference to the first preferred embodiment (1 12A) of the valve assembly (112) is contemplated as being performed via a unidirectional, sustained relative motion of rotor (1 12R) and housing (132) such that the first slice (142) is subject to a residence time (at the second peripheral port pair) in the range of approximately 1 to 100 milliseconds. Assuming an 50 micrometer capillary column with a capillary column linear velocity of approximately 0.1 to 1 centimeters/second, a sample volume ranging from approximately 20 picoliters to 20 nanoliters may be delivered to the column (186). Such an ultra small amount is considerably less than the volume of sample fluid typically delivered by a rotary sample valve of the prior art.

14 Hence, it is a particular feature of the first preferred embodiment (1 12A) that the rotor (1 12R) and the housing (132) move from an initial configuration such that the first slice (142) is aligned with the first pedpheral pcr.1, pair (121) in a sustained, unidirectional relative motion without reversal to pass the abovedescribed first intermediate position wherein the first slice is aligned with the second peripheral port pair (122). Any further relative motion may be sustained or discontinuous, but nonetheless is unidirectional (without reversal) until the valve assembly (12A) assumes the final "reset" configuration wherein the first slice is again aligned with the first peripheral port pair (121). The denotation of the relative motion as sustained and unidirectional is thus meant herein to distinguish the valves of the prior art which rely upon a reversal in the motion of a rotor (or similar component) to effect an injection.

As shown in Figures 5A, 513, 5C, and 51), a second preferred embodiment (11213) of the valve assembly (112) may be operated in a sample delivery cycle whereby a predetermined volume of a sample fluid may be provided to the column (186). The second preferred embodiment differs from the first preferred embodiment by omitting the second slice (144), by altering the pressure settings of the sample fluid flow in the sample fluid line (S) and the mobile phase fluid flow in the pump line (P), and altering the orientation of the rotor (1 12R) and housing (132), as will now be described.

Figure 5A illustrates the second preferred embodiment (11213) in an initial configuration wherein a regulated flow of mobile phase fluid may pass from the pump line (S) and pump line port (138P) through the first slice (142) and the column line port (13BW) into the column (186). The rotor driver (170) is actuated and the arresting cam (66) is retracted (not necessarily in that order) so as to initiate high speed relative motion of the rotor (1 12R) and housing (132). Figure 5B illustrates the second preferred embodiment (11213) in a first

intermediate configuration that precedes sample delivery. The first slice (142), is which now contaihs a trapped volume of mobile phase fluid under pressure, is located at a position intermediate between the first and second pairs of peripheral ports and hence is not in communication with any of the peripheral ports. The regulated flow of mobile phase fluid from the pump line (P) to the column line (C) is momentarily interrupted while the first slice (142) is no longer in fluid communication with the second peripheral port pair. The arresting cam (66) is returned to its initial position such that the rotation of the rotor (112R) will be arrested at the sample delivery configuration (Figure 5D).

Figure 5C illustrates the second preferred embodiment (112) in a second intermediate configuration that precedes sample delivery. The rotor (112R) is positioned such that the first slice (142) communicates with the sample inject port (138S) and the waste line port (138W). The sample inject line (138S) is preferably at a pressure higher than that of the trapped mobile phase, and the waste line (138W) is preferably at a pressure lower than that of the trapped mobile phase.

Accordingly, the first slice (142), which still contains a trapped volume of mobile phase fluid under pressure, momentarily allows sample fluid flow from the sample inject line port (138P) to the waste line port (138C) through the first slice (142). Excess sample fluid is allowed to pass into the waste line port (1 38W) and exits the valve assembly via the waste line (W). The mobile phase fluid trapped in the first slice (142) is also vented to the waste line (1 38W). As!he rotor (1 12R) continues its rotation, the first slice (142) is moved away from the sample inject line port (182S) and the waste line port (182W) until sealed by the housing bore (150). A predetermined volume of sample fluid is then carried by the first slice (142).

Figure 5D illustrates the second preferred embodiment (112B) in a final configuration adapted for sample injection and for resetting the valve assembly. The relative motion of the rotor (112R) and housing (132) is arrested upon the contact of the stop pin (154) with the arresting cam (66). The rotor (112 R) is then positioned such that the first slice (142) again communicates with the pump line 16 port (138P) and the column line port (138C). The predetermined volume of sample fluid, previously trapped in the first slice, is thus subject to the renewed flow of the mobile phase fluid from the pump line (P) through the first slice (142) into the column (186). The trapped sample volume is thereby injected into the regulated flow of mobile phase fluid flowing from the pump line (S) and pump line port (138P) through the first slice (142) and the column line port (138W) into the column (186). The valve assembly (112) is thereby reset and ready for another cycle of sample loading and delivery.

The foregoing sample injection sequence described with reference to the second preferred embodiment (11213) of the valve assembly (112) is contemplated as being performed in at least one unidirectional, sustained relative motion of the rotor (1 12R) with respect to the housing (132) at a high rotational speed such that the first slice (142) is subject to a residence time (at the first peripheral port pair) in the range of approximately 1 to 100 milliseconds, and such that an ultra small sample volume may be captured in the first slice (142) for delivery into the column (186). Further, the rotation is contemplated as being executed at sufficiently high speed so as to incur minimal interruption of the mobile phase fluid flow from the pump line (P) to the column line (C).

Hence, it is a particular feature of the second preferred embodiment (11213) that the rotor (1 12R) and the housing (132) may assume an initial configuration such that the first slice (142) is aligned with the second peripheral port pair (122) and thereafter pass an intermediate position wherein the first slice is aligned with the first peripheral port pair (121) in a sustained, unidirectional relative motion without reversal, so as to thereafter assume a final position wherein the first slice is again aligned with the second peripheral port pair (122).

As described in the foregoing, the valve assembly (112) is preferred for the delivery of an ultra small volume of sample fluid to an analyzer (116). However, the contemplated valve assembly will find application for 17 the delivery of a ultra small volume of fluid into other sample handling systems having differing or additional components attached to, or in fluid communication with, the valve assembly (112). For example, the contemplated delivery of a sample volume is not limited to only a separation column. It will be appreciated that the valve assembly may include or be operated with additional components such as fittings, piping, tubing, fluid pumps, needles, canulas, drains, filters, and other apparatus or devices connected by suitable fluid conveyance means to the valve assembly. While such systems are not shown in the Figures, they are contemplated as being amenable to use with the valve assembly (112).

The valve assembly (112) may be modified to include an additional stop pin (154) and an additional cam (66) such that the relative motion of the rotor (1 12R) and housing (132) may be limited to other than 360 degrees. In another alternative, the stop pin (154) and cam (66) may be omitted to allow repeated, full rotations of the rotor (1 12R), such that the valve assembly (112) may be operated as a modulated valve to deliver a series of discrete, ultra-small volumes of a sample fluid to the column line (C) or similar fluid-handling device.

The disclosures in United States patent application no. 08/260,598, from which this application claims priority, and in the abstract accompanying this application, are incorporated herein by reference.

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Claims (18)

1 A rotary injection valve, comprising a rotor including an exterior surface and a slice on the exterior surface; and a housing including a central bore for receiving the rotor and first and second pairs of peripheral ports spaced about a central axis; wherein the rotor is positionable in the bore by relative motion between the housing and the rotor in a sustained motion about the central axis from an initial configuration, wherein the slice can be aligned with the second pair of peripheral ports so as to effect fluid communication therebetween, and can pass an intermediate position wherein the slice is aligned with the first pair of peripheral ports so as to effect momentary fluid communication therebetween.

2. A rotary injection valve as in claim 1, wherein the momentary fluid communication of the slice at the first peripheral port is limited by a residence time in the range of approximately 1 to 100 milliseconds.

3. A rotary injection valve, comprising a rotor including an exterior surface and first and second slices on the exterior surface; and a housing including a central bore for receiving the rotor and first and second pairs of peripheral ports spaced about a central axis; wherein the rotor is positionable in the bore by relative motion between the housing and the rotor in a sustained motion about the central axis from an initial configuration, wherein the first slice can be aligned with the first pair of peripheral ports so as to effect fluid communication therebetween and the second slice can be aligned with the second pair of peripheral ports so as to effect fluid communication therebetween, the rotor being able to pass an intermediate position wherein the first slice is aligned with the second pair of peripheral ports so as to effect momentary fluid communication therebetween.

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4. A rotary injection valve as in claim 3, wherein the momentary fluid communication of the first slice at the second peripheral port pair is limited by a residence time in the range of approximately 1 to 100 milliseconds.

5. A rotary injection valve as in any preceding claim, comprising a relative motion driver for effecting the relative motion.

6. A rotary injection valve as in claim 5, wherein the relative motion driver is operative to provide selectable angular rotation of the rotor within the bore while the housing is held stationary.

7. A rotary injection valve as in claim 5 or 6, wherein the relative motion driver is a pneumatic rotor driver.

8. A rotary injection valve as in claim 5 or 6, wherein the relative motion driver is electrical rotor driver.

9. A rotary injection valve as in any preceding claim, comprising a relative motion limiter.

10. A rotary injection valve of claim 9, wherein the relative motion limiter comprises a stop pin on the rotor and arrest means for arresting the motion of the rotor at the stop pin.

11. A rotary injection valve according to any preceding claim, wherein the rotor is positioned by unidirectional sustained motion.

12. A sample analysis system for analysis of the constituent components of a sample fluid present in a sample inject line, comprising a rotor including an exterior surface and first and second slices on the exterior surface; a housing including a central bore for receiving the rotor and first and second pairs of peripheral ports spaced about a central axis, the first pair of peripheral ports being operatively connected to the sample inject line and a waste line, and the second pair of peripheral ports being operatively connected to a pump line and a column line; wherein the rotor is positionable in the bore by relative motion between the housing and the rotor in a sustained motion about the central axis from an initial configuration, wherein the first slice can be aligned with the first pair of peripheral ports so as to effect fluid communication between the sample line and waste line for capture of a predetermined sample fluid volume, and the second slice can be aligned with the second pair of peripheral ports so as to effect fluid communication between the pump line and column line, the rotor being able to pass an intermediate position wherein the first slice is aligned with the second pair of peripheral ports so as to effect momentary fluid communication therebetween for delivery of the sample volume to the column line and thereafter to assume a final position, wherein the first slice is aligned with the first pair of peripheral ports so as to effect fluid communication between the sample line and waste line and the second slice is aligned with the second pair of peripheral ports so as to effect fluid communication between the pump line and column line; a mobile phase source operatively connected to the pump line for supplying pressurized mobile phase thereto; and a sample analyzer operatively connected to the column line for receiving the sample volume.

13. A sample analysis system as in claim 12, wherein the analyzer comprises a separation device for separating constituent components of the sample volume; and a detector for detecting the separated components.

14. A sample analysis system as in claim 12 or 13, wherein the separation device comprises a separation column in the form of a capillary silica column.

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15. A method of accomplishing chromatographic separation and detection of constituent components of a sample fluid present in a sample inject line, comprising the steps of providing a high speed injection valve comprising a rotor including an exterior surface and first and second slices on the exterior surface and a housing including a central bore for receiving the rotor and first and second pairs of peripheral ports spaced about a central axis; connecting the first pair of peripheral ports to the sample inject line and a waste line, and the second pair of peripheral ports to a pump fine and a column line; supplying a pressurized mobile phase to the pump line; positioning the rotor and the housing in an initiai configuration, wherein the first slice is aligned with the first pair of peripheral ports so as to effect fluid communication between the sample fine and waste line for capture of a predetermined sample fluid volume, and the second slice is aligned with the second pair of peripheral ports so as to effect fluid communication between the pump line and column line; effecting unidirectional sustained relative motion of the rotor and the housing about the central axis from the initial configuration to pass an intermediate configuration, wherein the first slice is aligned with the second pair of peripheral ports so as to effect momentary fluid communication therebetween for delivery of the sample volume to the column line; positioning the rotor and the housing in a final conrigLral.. on, wherein the first slice is aligned with the first pair of peripheral ports sc as to efflect fluid communication between the sample line and waste line, and the second slice is aligned with the second pair of peripheral parts so as to effect fluid communication between the pump line and column line; and analyzing the sample volume in the column line at a sample analyzer.

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16. A rotary injection valve substantially as hereinbefore described with reference to and as illustrated in Figures 3 to 5D of the accompanying drawings.

17. A sample analysis system substantially as hereinbef ore described with reference to and as illustrated in Figures 3 to 5D of the accompanying drawings.

18. A method of accomplishing chromatographic separation and detection of constituent components of a sample fluid substantially as hereinbefore described with reference to Figures 3 to 5D of the accompanying drawings.