Atmospheric solids analysis probe assembly

Abstract

A nozzle for directing heated gas onto a distal end of a capillary tube arrangeable in the vicinity of the nozzle, the nozzle comprising: a housing defining a cavity for the heated gas; and an outlet comprising at least one orifice fluidly connected to the cavity, the outlet configured to direct, in use, a curtain of heated gas onto the distal end of the capillary tube such that the curtain of heated gas is substantially aligned with a longitudinal axis of the capillary tube.

Description

Technical Field

[0001] This invention relates to a nozzle for directing heated gas to the distal end of a capillary. The invention further relates to a source assembly including the nozzle. Background Technology

[0002] This invention generally relates to atmospheric solids analysis probes (ASAPs). Such probes and associated instruments used with ASAPs are provided by several manufacturers, including Waters Corporation of Milford, Massachusetts, USA.

[0003] ASAP is a useful and relatively inexpensive tool for the direct analysis of volatile and semi-volatile, solid and liquid samples, and can be used in the analysis of specialty chemicals, synthetic polymers, energy and food.

[0004] The sample is introduced into the ion source housing (e.g., an API source), where a heated gas (such as nitrogen) is used to volatilize the sample, and then the sample is ionized using, for example, a corona discharge needle. The ionized sample can then be analyzed in a mass spectrometer.

[0005] The sample is introduced into the source by loading it onto the tip of a capillary. The capillary can be a conventional glass capillary. The capillary can be a tube with an open end or a solid rod.

[0006] Capillaries are fragile and susceptible to contamination. To ensure reliable and accurate analysis, the capillary tip must be inserted into the source in a repeatable manner.

[0007] To aid in loading a capillary into a source, a retainer including a clamping mechanism is known to hold the proximal end of the capillary (opposite to the tip at the distal end carrying the sample) within the capillary retainer. This provides the user with a more robust method of handling the capillary and also aids in guiding the capillary into the source. The capillary retainer and / or source instrument may include a guiding mechanism to ensure proper alignment of the capillary when loading it into the source.

[0008] When a capillary is arranged within an ion source housing, its distal end is positioned adjacent to the outlet of a nozzle used to guide heated gas onto the capillary. The outlet may include a single circular orifice configured to optimize the velocity and flow rate of the heated gas exiting the outlet and being guided to the distal end of the capillary. However, the "beam" of hot gas exiting the single circular orifice may not be wide enough to effectively heat and evaporate substantially all of the sample positioned at the distal end of the capillary.

[0009] If a large amount of sample is not adequately heated by the nozzle, it may subsequently fail to volatilize effectively into the gas phase and therefore will not be ionized by the corona discharge needle. This can thus reduce the speed and accuracy of subsequent measurements. Inefficient volatilization caused by incomplete heating of the sampling region can lead to prolonged analysis times, with high-quality, high-boiling-point compounds volatilizing during extended periods and appearing as undesirable background in mass spectrometry and subsequent analyses.

[0010] Increasing the size of a single circular orifice, and thus the diameter of the hot gas jet, adversely affects the velocity and / or flow rate of the heated gas, and also adversely affects the temperature of the heated gas as it exits the nozzle. This, in turn, adversely affects the measurement results derived from the ionized sample.

[0011] Furthermore, in practice, the accurate positioning of the distal end of the capillary tip relative to the heater outlet may not be achievable. This could be due to the cumulative tolerances of various mechanical arrangements of the ASAP assembly (e.g., clamps, guide mechanisms, and / or ion source housing). Therefore, even capillaries of substantially the same length may have a different distal end position relative to the heater outlet than another capillary. Consequently, what is optimal for a single orifice outlet relative to the distal end may not be optimal for subsequent capillaries loaded into the source assembly. Summary of the Invention

[0012] The present invention attempts to solve at least one of the above-mentioned problems.

[0013] Therefore, the present invention provides a nozzle for guiding heated gas to the distal end of a capillary tube disposed near the nozzle, the nozzle comprising:

[0014] A shell defining the cavity (or chamber, or plenum) for the gas to be heated; and

[0015] The outlet includes at least one orifice fluidly connected to the cavity, the outlet being configured to guide a curtain of heated gas to the distal end of the capillary during use, such that the heated gas curtain is substantially aligned with the longitudinal axis of the capillary.

[0016] In at least one embodiment, the outlet comprises a plurality of orifices arranged substantially linearly.

[0017] In at least one embodiment, the outlet includes four orifices.

[0018] In at least one embodiment, each of the orifices has substantially the same surface area.

[0019] In at least one embodiment, each of the orifices is substantially circular.

[0020] In at least one embodiment, the orifice(s) is non-circular.

[0021] In at least one embodiment, the orifice(s) is elongated.

[0022] In at least one embodiment, the outlet comprises a single elongated orifice.

[0023] In at least one embodiment, the outlet includes a plurality of elongated orifices, wherein the elongation direction is substantially perpendicular to the plane of the heated gas curtain.

[0024] In at least one embodiment, the nozzle further includes a heater arrangement for heating the gas in the cavity.

[0025] In at least one embodiment, the housing includes a cylindrical outer sleeve and a substantially planar plate located at the distal end of the sleeve, wherein an outlet is disposed in the plate.

[0026] In at least one embodiment, the nozzle further includes a gas source for delivering gas into the cavity.

[0027] In at least one embodiment, the gas is nitrogen.

[0028] The present invention further provides a source component comprising:

[0029] A source housing configured to receive at least the distal end of a capillary therein; and

[0030] According to the invention, the nozzle, which is received in the source housing, is configured such that the gas curtain heated in use is substantially aligned with the longitudinal axis of the capillary.

[0031] In at least one embodiment, the source assembly further includes a capillary, wherein the distal end of the capillary is received in the source assembly, and the heated gas curtain is substantially aligned with the longitudinal axis of the capillary. Attached Figure Description

[0032] Embodiments of the invention will now be described with reference to the following figures, which are merely non-limiting examples, in which:

[0033] Figure 1 The nozzle embodying the invention is shown;

[0034] Figure 2a A source assembly including a nozzle embodying the present invention is shown;

[0035] Figure 2b It shows Figure 2a Detail C;

[0036] Figures 3a to 3d Various embodiments of the nozzle outlet embodying the present invention are shown;

[0037] Figures 4a to 4c The nozzle embodying the invention is shown;

[0038] Figure 5 A cross-sectional view of the nozzle embodying the invention is shown; and

[0039] Figure 6 The diagram shows the positioning of the distal end of the capillary relative to the nozzle outlet during use. Detailed Implementation

[0040] Figure 1 The nozzle 1 embodying the present invention is shown. Figure 6 The image shows a nozzle 1 for directing heated gas to the distal end 51 of a capillary 50 that may be arranged near the nozzle 1.

[0041] The nozzle 1 includes a housing 2 that defines a cavity 3 for heating gas.

[0042] The nozzle 1 further includes an outlet 4, which includes at least one orifice 5. The outlet 4 is fluidly connected to the cavity 3. The outlet 4 is configured to guide a heated gas curtain 6 onto the distal end 51 of the capillary 50. The heated gas curtain 6 is substantially aligned with the longitudinal axis 52 of the capillary 50. Figure 6 and 2b As shown in the image.

[0043] The heated gas curtain 6 has a plane, and the longitudinal axis of the capillary 50 is substantially aligned with this plane. While absolute alignment may be preferred, substantial alignment of the heated gas curtain 6 with the longitudinal axis 52 of the capillary 50 is acceptable. For example, the angle of the longitudinal axis 52 of the capillary 50 relative to the plane of the heated gas curtain 6 can be within an acceptable range. This range can be between -10° and +10°, between -5° and +5°, between -2.5° and +2.5°, or between -1° and +1°.

[0044] The heated gas curtain 6 has a width and a length. The length is greater than the width. Therefore, the heated gas curtain 6, guided from the outlet 4 of the nozzle 1 embodying the invention, is effectively "extended." This contrasts with the circular jet of hot gas provided by a single circular orifice in an arrangement outside the scope of the claimed invention (discussed above). The advantage of the outlet 4 of the claimed invention providing the heated gas curtain 6 is that it provides more effective coverage of the distal end 51 of the capillary 50, ensuring that more sample placed on the distal end 51 of the capillary 50 is effectively heated (compared to a single circular orifice in an arrangement outside the scope of the claimed invention). Without the heated gas curtain provided by the embodiments of the invention, the heated gas may not effectively cover the distal end 51 of the capillary 50. Some of the sample would then not be directly heated by the heated gas flow, but instead would be heated by latent heat conduction through the capillary, the sample, or any coating that may be present on the capillary tip. This would distort the obtained measurement results.

[0045] The width of the curtain 6 can be configured to be substantially equal to the diameter / width of the capillary 50, and the length of the curtain 6 can be configured to be substantially equal to the length of the distal end 51 of the capillary 50 provided to hold the sample.

[0046] Figures 3a to 3d Various arrangements of the outlet 4 of the nozzle 1 embodying the present invention are shown.

[0047] exist Figure 3a In this embodiment, outlet 4 includes three orifices 5. Each of the orifices 5 is substantially circular. The orifices 5 are arranged in a line and are evenly distributed along it. This is not required. In an alternative embodiment not shown, each of the orifices 5 may have a different size and / or shape. The middle orifice of the three orifices 5 may be closer to one of the outer orifices 5 than the others.

[0048] Figure 3b The outlet 4 comprises four circular openings 5, all of which are substantially the same size and linearly distributed. (Compared to...) Figure 3a Similar to the arrangement in the diagram, the orifice 5 may alternatively have different sizes and / or shapes, and may be compatible with... Figure 3a The different distributions shown are illustrated.

[0049] In other embodiments of the invention, two circular openings 5 ​​may be provided. In other embodiments, five, six, seven, eight or more openings 5 ​​may be provided.

[0050] exist Figure 3b In this configuration, the orifice 5 located at one end of a series of orifices 5 is substantially aligned with the central axis of the nozzle 1. This is not necessary. Figure 3aIn the arrangement shown, a series of orifices 5 extend across the central axis of the nozzle 1. The outlet 4 of the nozzle 1 embodying the invention can be configured such that the heated gas curtain 6 is offset from the central axis of the nozzle 1, or it can be centrally aligned.

[0051] Figure 3c An outlet 4 of another nozzle 1 embodying the invention is shown, which includes a single orifice 5. The orifice 5 is non-circular and elongated. (As will be...) Figure 3c It is noted that the length of orifice 5 is greater than its width. Therefore, Figure 3c The outlet arrangement shown produces a heated gas curtain 6. This contrasts with the circular heated gas stream produced by a single circular orifice, as discussed above.

[0052] Figure 3d An outlet 4 of a nozzle 1 according to another embodiment of the invention is shown. In this embodiment, the outlet 4 includes a plurality of orifices 5 (four in this example), and each of the orifices 5 is elongated. The direction of elongation is substantially perpendicular to the plane of the heated gas curtain 6 generated by the outlet. It will be appreciated that, for Figure 3d The structure of the outlet 4 shown in the diagram, compared to an arrangement including four circular openings 5, increases the width of the curtain 6 due to the elongated openings 5.

[0053] In other embodiments falling within the scope of the claims, the aperture 5 may be employed in conjunction with... Figures 3a to 3d The different forms and / or shown Figures 3a to 3d The examples illustrate combinations of these forms. For instance, outlet 4 may include a plurality of orifices 5, wherein at least one of the orifices 5 is circular, and at least one of the orifices 5 is elongated. In embodiments including a plurality of elongated orifices 5, the elongation direction of one orifice 5 may differ from the elongation direction of another orifice 5 of the outlet 4.

[0054] In at least one embodiment, the total surface area of ​​one or more orifices 5 of the outlet 4 of the nozzle 1 embodying the present invention may be 8 to 8.5 mm. 2 Within the range. In one embodiment, the total surface area can be between 8.1 and 8.4 mm. 2 Within a certain range. In another embodiment, this range can be from 8.2 to 8.3 mm. 2 Between. In another embodiment, the total surface area may be 8.245 mm. 2 .

[0055] In an embodiment of the invention, nozzle 1 may be configured to deliver heated gas through outlet 4 at a flow rate between 1 and 4 liters per minute. In another embodiment, the flow rate may be between 2 and 3 liters per minute. In another embodiment, the flow rate may be between 2.3 and 2.7 liters per minute. In another embodiment, the flow rate may be substantially 2.5 liters per minute. In another embodiment, the flow rate may be substantially 4 liters per minute.

[0056] like Figure 5 As shown, nozzle 1 may further include a heater arrangement 7 for heating the gas in cavity 3. Nozzle 1 may further include a gas source 8. The gas is preferably nitrogen. Gas source 8 may be configured to introduce gas into cavity 3 of nozzle 1. Heater arrangement 7 is arranged to heat the gas introduced into cavity 3. Heater arrangement 7 may be arranged in the path of gas from gas source 8 into cavity 3 so as to effectively heat the gas using heater arrangement 7.

[0057] The housing 2 includes a cylindrical outer sleeve 9 and a generally planar plate 10 located at the distal end of the sleeve 9. An outlet 4 is disposed in the plate 10. The cylindrical outer sleeve 9 and the plate 10 are hermetically sealed to define a cavity 3 therein. Preferably, any heated gas within the cavity 3 can only exit the cavity 3 through the outlet 4 (assuming a gas source 8 communicating with the cavity 3 provides positive pressure and / or a one-way valve).

[0058] The planar nature of plate 10 is not required. The reader will recognize that it can take other forms, such as concave or convex. The cylindrical nature of outer sleeve 9 is also not required. In other forms, it can be non-circular, such as having a square or rectangular cross-section. Correspondingly, the shape of plate 10 can be non-circular, depending on the cross-sectional shape of outer sleeve 9.

[0059] like Figures 4a to 4c As shown, the nozzle 1 may further include a mounting flange 12, which may be substantially planar. Figure 4a As shown, the outer sleeve 9 of the nozzle 1 can be received in the orifice in the mounting flange 12.

[0060] In at least one embodiment, such as Figures 4a to 4c As best shown, the outer sleeve 9 may include at least one flat portion 13 extending along the longitudinal length of the sleeve 9, rather than being entirely cylindrical. The orifice in the mounting flange 12 may be similarly shaped so that the outer sleeve 9 receives the nozzle 1 only therein in a predetermined orientation. Figures 4a to 4c As seen, the mounting flange 12 further includes an alignment feature 14 in the form of a pin.

[0061] In at least one embodiment, the source housing 20 includes a corresponding orifice for receiving the positioning pin 14. Therefore, since the angular alignment of the positioning pin 14 is achieved by means of the flat portion 13 on the outer sleeve 9 relative to the outlet 4 of the nozzle 1, the position of the outlet 4 of the nozzle 1 is fixed relative to the source housing 20. Thus, as... Figure 2b As shown, the locating pin 14 ensures that the nozzle 1 is repeatedly inserted into the source housing 20, so that the heated gas curtain 6 is substantially aligned with the longitudinal axis 52 of the capillary 50 during use.

[0062] In at least one embodiment, the nozzle 1 is configured such that it can only be inserted into the source housing 20 in a single orientation.

[0063] The advantage of providing a flat portion 13 on the outer sleeve 9 is that it facilitates the assembly and manufacture of the nozzle 1. During manufacturing, the outer sleeve 9 can be inserted into an orifice in the mounting flange 12 in a specific orientation, and then the outer sleeve 9 can be fixed to the mounting flange 12, for example, by welding or other means.

[0064] like Figure 5 As shown, nozzle 1 may further include an inner sleeve 15 and an intermediate sleeve 16 located within a cavity. The intermediate sleeve 16 is arranged between the outer sleeve 9 and the inner sleeve 15. The outer sleeve 9, intermediate sleeve 16, and inner sleeve 15 create a labyrinthine / zigzag path for the gas to travel from the gas source 8 to the outlet 4. Figure 5 In the illustrated embodiment, the heating element of the heater arrangement 7 is located between the outer sleeve 9 and the intermediate sleeve 16. Gas can enter one end of the first section 21 between the outer sleeve 9 and the intermediate sleeve 16, and pass through to the other end of the first section 21. From there, the gas can enter the second section 22 between the intermediate sleeve 16 and the inner sleeve 15. Thus, the gas passes through the heater arrangement 7 again. In at least one embodiment, the intermediate sleeve 16 may be conductive and facilitate heat transfer to the gas. Finally, the gas can enter the third section 23 inside the inner sleeve 15, passing through the heater arrangement 7 again to further heat the gas.

[0065] The heated gas then exits the inner sleeve 15 through outlet 4. The advantage of providing the inner sleeve 15 and the intermediate sleeve 16 is that it increases the path through which the gas contacts the heater arrangement 7, thereby improving the efficiency of the heater arrangement 7.

[0066] When used in this specification and claims, the terms "comprise" and "comprising," and variations thereof, mean to include the specified features, steps, or integers. These terms should not be construed as excluding the presence of other features, steps, or components.

[0067] Features disclosed in the foregoing description or the following claims or drawings, expressed in their specific form or according to the means for performing the disclosed functions, or the methods or processes for obtaining the disclosed results (as the case may be), may be used alone or in any combination of such features to implement the invention in its various forms.

[0068] Although certain exemplary embodiments of the invention have been described, the scope of the appended claims is not intended to be limited to these embodiments. The claims should be interpreted literally, purposively, and / or include equivalents.

Claims

1. A nozzle (1) for directing heated gas onto a distal end (51) of a capillary (50) disposed near the nozzle (1), the nozzle (1) comprising: The shell (2) defines the cavity (3) for the gas to be heated; as well as The outlet (4) includes at least one orifice (5) fluidly connected to the cavity (3), the outlet (4) being configured to guide a heated gas curtain (6) to the distal end (51) of the capillary (50) in use, such that the plane of the heated gas curtain (6) is aligned with the longitudinal axis (52) of the capillary (50).

2. The nozzle (1) according to claim 1, wherein, The outlet (4) includes a plurality of orifices (5) arranged linearly.

3. The nozzle (1) according to claim 1, wherein, The outlet (4) includes four openings (5).

4. The nozzle (1) according to claim 2, wherein, Each of the orifices (5) has the same surface area.

5. The nozzle (1) according to claim 2, wherein, Each of the orifices (5) is circular.

6. The nozzle (1) according to claim 1, wherein, Each of the orifices (5) is non-circular.

7. The nozzle (1) according to claim 6, wherein, Each of the orifices (5) is elongated.

8. The nozzle (1) according to claim 6, wherein, The outlet (4) includes a single elongated orifice (5).

9. The nozzle (1) according to claim 6, wherein, The outlet (4) includes a plurality of elongated orifices (5) wherein the elongation direction is perpendicular to the plane of the heated gas curtain (6).

10. The nozzle (1) according to any one of claims 1 to 9, wherein, The nozzle further includes a heater arrangement (7) for heating the gas in the cavity (3).

11. The nozzle (1) according to any one of claims 1 to 9, wherein, The housing (2) includes a cylindrical outer sleeve (9) and a flat plate (10) located at the distal end of the sleeve (9), wherein the outlet (4) is disposed in the plate (10).

12. The nozzle (1) according to any one of claims 1 to 9, wherein, The nozzle further includes a gas source (8) for delivering gas into the cavity (3).

13. The nozzle (1) according to claim 12, wherein, The gas is nitrogen.

14. A source component, comprising: Source housing (20), configured to receive at least the distal end (51) of capillary (50) therein; as well as The nozzle (1) according to any one of claims 1 to 13 is received in the source housing (20) and configured such that, in use, the plane of the heated gas curtain (6) is substantially aligned with the longitudinal axis (52) of the capillary (50).

15. The source component according to claim 14, wherein, The source assembly further includes a capillary (50), wherein a distal end (51) of the capillary (50) is received in the source assembly, and the plane of the heated gas curtain (6) is substantially aligned with the longitudinal axis (52) of the capillary (50).

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