Gasket seal for a mass spectrometer

Abstract

A gasket seal for a mass spectrometer is disclosed. The gasket seal comprises a membrane having an outer profile and an inner profile and one or more protrusions. One or more ports are provided in the body of the membrane. In use a gas or fluid is supplied through at least one of the one or more ports via at least one of the one or more protrusions.

Claims

1. A gasket seal for a mass spectrometer, wherein said gasket seal comprises: a membrane having an outer profile and an inner profile; and one or more protrusions; wherein one or more ports are provided in the body of said membrane, and wherein in use a gas or fluid is supplied through at least one of said one or more ports via at least one of said one or more protrusions.

2. A gasket seal as claimed in claim 1, wherein said membrane is arranged substantially in a first plane, and wherein: at least one of said protrusions extends from said membrane in a direction orthogonal to said first plane; and/or at least one of said protrusions extends from said membrane in a direction that is not orthogonal to said first plane.

3. A gasket seal as claimed in claim 1, wherein said membrane is arranged substantially in a first plane, and wherein: an end surface of at least one of said protrusions is parallel to said first plane; and/or an end surface of at least one of said protrusions is not parallel to said first plane.

4. A gasket seal as claimed in claim 3, wherein said end surface of said at least one of said protrusions comprises a sealing surface.

5. A gasket seal as claimed in claim 1, wherein at least a portion of at least one of said protrusions is substantially straight, non-straight, curved, angled or kinked.

6. A gasket seal as claimed in claim 1, wherein said one or more ports are located in said membrane between said outer profile and said inner profile.

7. A gasket seal as claimed in claim 1, wherein said outer profile is substantially circular or non-circular.

8. A gasket seal as claimed in claim 1, wherein said inner profile is substantially circular or non-circular.

9. A gasket seal as claimed in claim 1, wherein at least one of said ports comprises a high pressure gas port or a gas port.

10. A gasket seal as claimed in claim 1, further comprising a device arranged and adapted to supply a cone gas, calibration gas or other gas through said at least one of said one or more ports via said at least one of said one or more protrusions.

11. A gasket seal as claimed in claim 1, wherein at least one of said ports comprises a liquid port.

12. A gasket seal as claimed in claim 11, further comprising a device arranged and adapted to supply a solvent or other liquid through said at least one liquid port.

13. A gasket seal as claimed in claim 1, further comprising one or more apertures provided in the body of said membrane.

14. A gasket seal as claimed in claim 13, wherein said one or more apertures are located between said outer profile and said inner profile.

15. A gasket seal as claimed in claim 13, wherein in use one or more fixings pass through said one or more apertures.

16. A mass spectrometer comprising: a first component; a second component; and a gasket seal as claimed in claim 1, wherein said gasket seal is located between said first component and said second component.

17. A mass spectrometer as claimed in claim 16, wherein said first component comprises a first mating surface and said second component comprises a second mating surface, wherein said gasket seal is arranged and adapted to provide a gas tight seal and/or vacuum seal between said first mating surface and said second mating surface.

18. A mass spectrometer as claimed in claim 17, wherein said gasket seal is arranged and adapted to provide a gas tight seal and/or vacuum seal between said first mating surface and said second mating surface whilst under compression.

19. A mass spectrometer as claimed in claim 16, wherein at least one of said one or more protrusions is arranged and adapted to extend into said first and/or second component.

20. A mass spectrometer as claimed in claim 16, wherein at least one of said one or more protrusions is arranged and adapted to form a seal with surrounding parts or portions of said mass spectrometer.

21. A mass spectrometer as claimed in claim 16, wherein in use said gas is supplied from said first component to said second component or from said second component to said first component through said at least one of said ports via said at least one of said protrusions.

22. A mass spectrometer as claimed in claim 16, wherein said first component comprises an ion block or a first vacuum chamber and said second component comprises a pumping block, a main housing of said mass spectrometer or a second vacuum chamber.

23. A mass spectrometer as claimed in claim 16, further comprising one or more third components, wherein at least one of said one or more protrusions is arranged and adapted to form a seal between said one or more third components and/or said first or second component.

24. A mass spectrometer as claimed claim 23, wherein in use said gas is supplied from said first and/or second component to said one or more third components or from said one or more third components to said first and/or second component through said at least one of said ports via said at least one of said protrusions.

25. A mass spectrometer as claimed in claim 23, wherein said one or more third components comprises an ion inlet assembly.

26. A mass spectrometer as claimed in claim 16, wherein said mass spectrometer comprises a miniature mass spectrometer.

27. A method of assembling a mass spectrometer comprising: providing a first component; providing a second component; and locating a gasket seal as claimed in claim 1 between said first component and said second component.

28. A mass spectrometer comprising: an ion block having an atmospheric pressure interface; a housing comprising one or more vacuum chambers; and a gasket seal located between said ion block and said housing, said gasket seal comprising: a membrane having an outer profile and an inner profile; and a protrusion; wherein a port is provided in the body of said membrane and wherein a gas or fluid is supplied, in use, to said atmospheric pressure interface via said port and said protrusion.

29. A mass spectrometer as claimed in claim 28, wherein said port is located between said outer profile and said inner profile.

30. A method of mass spectrometry comprising: providing an ion block having an atmospheric pressure interface; providing a housing comprising one or more vacuum chambers; locating a gasket seal between said ion block and said housing, said gasket seal comprising a membrane having an outer profile and an inner profile and a protrusion, wherein a port is provided in the body of said membrane; and supplying a gas or fluid to said atmospheric pressure interface via said port and said protrusion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Various embodiments of the present invention, together with other arrangements given for illustrative purposes only, will now be described, by way of example only, and with reference to the accompanying drawings in which:

(2) FIG. 1 shows a gasket seal according to a preferred embodiment of the present invention which forms a seal between an ion block of a miniature mass spectrometer and a pumping block of the miniature mass spectrometer;

(3) FIG. 2 shows a gasket seal according to an embodiment of the present invention wherein the gasket seal is positioned on the rear of an ion block of a miniature mass spectrometer and is arranged to form a seal with a pumping block of the mass spectrometer;

(4) FIG. 3 shows a gasket seal according to an embodiment of the present invention wherein the gasket seal includes a protrusion through which a cone gas is supplied to an annular region between a sampling cone and a gas cone;

(5) FIG. 4 shows a gasket seal according to an embodiment of the present invention wherein an end sealing surface of the protrusion is not parallel to the plane in which the main body of the gasket seal lies;

(6) FIG. 5 shows a gasket seal according to an embodiment of the present invention wherein the axis along which the protrusion extends from the main body of the gasket is not orthogonal to the plane in which the main body of the gasket seal lies;

(7) FIG. 6 shows a gasket seal according to an embodiment of the present invention wherein the protrusion is kinked so as to connect non-aligned gas or fluid lines;

(8) FIG. 7 shows a conventional gasket seal arrangement;

(9) FIG. 8 shows a gasket seal according to an embodiment of the present invention located in a mass spectrometer wherein a gas cone is attached to an ion block with a clamp;

(10) FIG. 9 shows a gasket seal according to an embodiment of the present invention located in a mass spectrometer wherein the gas cone and the clamp have been removed from the ion block; and

(11) FIG. 10 shows a mass spectrometer according to an embodiment of the present invention wherein the gas cone and the clamp have been removed from the ion block.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(12) A preferred embodiment of the present invention will now be described with reference to FIG. 1.

(13) FIG. 1 shows a main gasket seal 1 according to an embodiment of the present invention which has multiple gas seal regions formed within the body of the seal 1. The preferred gasket 1 is arranged to perform with a range of different media flowing through the gasket 1. The gasket 1 may also be subjected to a wide range of pressures and temperatures.

(14) The gasket seal 1 as shown in FIG. 1 is preferably located on the rear surface of a pumping block (or ion source and vacuum housing interface) which is secured by fasteners to the main body of a mass spectrometer. The gasket seal 1 is preferably compressed in use when secured between the pumping block and the main body of the mass spectrometer. The outer lip 2 of the seal 1 preferably provides the main vacuum seal between the reduced pressure region within the pumping block and the vacuum within the vacuum chambers located in the main body of the mass spectrometer.

(15) The preferred gasket seal 1 is particularly suitable for incorporation into small geometric spaces where the use of individual O-ring seals would be problematic. The preferred gasket seal 1 is easy to fit and manufacture and is particularly suited for use with miniature mass spectrometers.

(16) A particularly preferred aspect of the present invention is that one or more ports are provided in the membrane of the gasket seal 1. For example, as shown in FIG. 1 a cone gas port 3 may be provided in the gasket seal 1 through which a cone gas is preferably supplied under pressure to an annular region formed between a sampling cone and a gas cone.

(17) One or more further ports may be provided in the membrane of the gasket seal 1. For example, as shown in FIG. 1 a pressure port 4 and/or a calibration gas port 5 may also be provided.

(18) The seal 1 as shown in FIG. 1 preferably includes a number of apertures 6 formed in the body of the seal 1 through which a fixing or fastener may be passed in use. In the particular example shown in FIG. 1 four apertures 6 are provided and a fastener such as an allen bolt preferably passes through each aperture 6 in order to secure the ion block to a pumping block of the mass spectrometer. This also compresses the seal 1.

(19) The seal 1 may include a relatively large aperture 7 which is preferably provided in the body of the seal 1 and which is preferably used as a port through which exhaust gas and solvent may escape.

(20) The seal 1 ensures that a gas tight and vacuum seal is preferably maintained with the apertures 6 through which fixings pass and the relatively large aperture 7 through which exhaust gas and solvent escapes.

(21) The preferred seal or gasket 1 preferably enables gas or fluid to be transported through ports provided in the membrane forming the seal 1 without breaking the vacuum and gas seal which is otherwise provided by the seal 1.

(22) The gasket or seal 1 is preferably housed within a geometry which preferably has a form which complements the geometry of the seal 1. The surrounding housing preferably includes a device which delivers the gas and/or fluids to the correct region.

(23) The seal 1 is preferably mechanically held in place under clamping pressure using mechanical fixings. The mechanical fixings are preferably sealed off to avoid leaks through these locations.

(24) The precise shape or form of the preferred seal or gasket 1 can be adapted to meet the needs of different applications. A particularly preferred aspect of the present invention is that the gasket seal 1 may include one or more protrusions which form a gas port through the gasket seal 1. The shape, length and location of the protrusions for gas transfer may vary.

(25) According to an embodiment the material or compound used to form the seal 1 may comprise different compounds or elastomers.

(26) The preferred seal 1 can be used in various different applications where gas and/or fluids require sealing.

(27) FIG. 2 shows a particularly preferred embodiment wherein a gasket seal 1 is used to provide a gas tight and vacuum tight seal between an ion block 8 of a miniature mass spectrometer and a pumping block 9 of the miniature mass spectrometer. The pumping block 9 is attached to the main housing of the mass spectrometer. One or more vacuum chambers are provided within the main housing of the mass spectrometer. An ion guide 10 is shown in FIG. 2 in a vacuum chamber provided within the main housing of the mass spectrometer. A mass analyser (not shown) is provided within a downstream vacuum chamber. The preferred seal 1 has multiple gas seal regions within the body of the main seal 1.

(28) FIG. 3 shows in more detail the preferred seal 1 located on the rear surface of an ion block 8 and which forms a gas tight and vacuum seal with a pumping block 9 of a miniature mass spectrometer. The seal 1 preferably includes one or more rubber protrusions 11. The one or more protrusions 11 preferably carry a gas in use and at the same time form a seal with surrounding parts or portions of the mass spectrometer. In the particular example shown in FIG. 3, a cone gas (e.g. nitrogen, air, carbon dioxide or sulphur hexafluoride (“SF.sub.6”)) is preferably supplied to an annular region formed between an inner sampling cone (not shown) and an outer gas cone 12. The cone gas is preferably supplied to the annular region via the protrusion 11 in the gasket seal 1.

(29) FIG. 4 shows a seal 1 having a port 13 provided in the main body of the seal 1 in accordance with a preferred embodiment. The main body of the seal 1 is preferably used to provide a gas tight and vacuum tight seal between first and second components of a mass spectrometer (e.g. between the ion block 8 and the pumping block 9), as discussed above. A protrusion 11 is provided and preferably forms part of the port 13, i.e. such that a gas or fluid may be supplied through the port 13 via the protrusion 11. The protrusion 11 preferably comprises a tube extending from the main body of the seal 1.

(30) According to the preferred embodiment, the protrusion 11 is arranged so as to reduce the number of potential seal leak points in the mass spectrometer. As shown in FIG. 4, the protrusion 11 preferably acts to reduce the number of possible leak points between the seal 1 and one of the components of the mass spectrometer, e.g. first component 14 into which the protrusion 11 preferably extends. As will be appreciated by those skilled in the art, movement of the first component 14 with respect to the seal 1 is less likely to cause a leak because of the protrusion 11.

(31) According to a preferred embodiment, the protrusion 11 is also used to provide an additional seal between the first component 14 and a third component 15 of the mass spectrometer. The first 14 and third 15 components are preferably separate components of the mass spectrometer. In one embodiment, the first component 14 comprises a portion of the ion block 8, and the third component 15 comprises a portion of an ion inlet assembly such as gas cone 12.

(32) Preferably, the protrusion 11 is arranged to extend through the first component 14 and preferably beyond the first component 14. The protrusion 11 is preferably relatively thick and self-supporting. The portion of the protrusion 11 that extends beyond the first component 14 is preferably arranged to contact the third component 15, preferably at an end surface 16 of the protrusion, so as to form a gas tight seal with the third component 15.

(33) In an embodiment the surfaces of the first component 14 and the third component 15 that are sealed by the protrusion 11 are parallel with the surfaces of the first component 14 and the second component (not shown in FIG. 4) that are sealed by the main body of the seal 1, i.e. parallel with the plane in which the main body of the seal 1 lies. As shown in FIG. 4, in another embodiment the surfaces of the first component 14 and the third component 15 that are sealed by the protrusion 11 are not parallel with the surfaces of the first component 14 and the second component (not shown in FIG. 4) that are sealed by the main body of the seal 1, i.e. not parallel with the plane in which the main body of the seal 1 lies.

(34) In an embodiment, the end sealing face 16 of the protrusion 11 is orthogonal to the axis along which the protrusion 11 extends, i.e. parallel to the plane in which the main body of the seal 1 lies. As shown in FIG. 4, in another embodiment, the end surface 16 of the protrusion 11 is not orthogonal to the axis along which the protrusion 11 extends, i.e. not parallel to the plane in which the main body of the seal 1 lies.

(35) A first gas or fluid path 17 is preferably provided through the first component 14 via the port 13 and the protrusion 11. A second gas or fluid path 18 is preferably provided through the third component 15. The second gas or fluid path 18 is preferably a continuation of the first gas or fluid path 17, i.e. such that a gas or fluid may be supplied through the first component 14 and the second component 15. In an embodiment, the first 17 and second 18 paths are aligned and parallel. As shown in FIG. 4, in another embodiment the first 17 and second 18 paths are not parallel. The angle 19 between the first 17 and second 18 paths can be selected as desired.

(36) In an embodiment, the first 14 and third 15 components are arranged to contact one another. As shown in FIG. 4, in another embodiment, a gap 20 may provided between the first component 14 and the third component 15. In this embodiment, the third component 15 is preferably supported in its position relative to the first component 14, preferably without compressive forces between the two components, e.g. by a supporting means or clamp. Advantageously, the protrusion 11 will still form a gas tight seal in this arrangement.

(37) This is in contrast with conventional arrangements such as the arrangement disclosed in GB-2471520 (Syms) in which the components must be clamped together under compression in order to effect a seal.

(38) It will furthermore be appreciated that the tolerance for movement of the two components relative to one another without breaching the seal is particularly high for the preferred gasket seal 1. Again, this is in contrast to conventional sealing arrangements.

(39) In an embodiment, e.g. as depicted in FIG. 4, the axis along which the protrusion 11 extends is orthogonal to the plane in which the main body of the seal 1 lies.

(40) FIG. 5 shows a seal 1 in accordance with another preferred embodiment. The seal 1 in this embodiment is similar to the seal 1 illustrated in FIG. 4, except that the protrusion 11 extends from the main body of the seal 1 at an acute angle. That is, the axis along which the protrusion 11 extends is preferably not orthogonal to the plane in which the main body of the seal 1 lies. The angle at which the protrusion 11 extends from the main body of the seal 1 can be selected as desired. In this embodiment, preferably the port 13 and the end of the protrusion 11 are offset in a direction parallel to the plane in which the main body of the seal 1 lies. The distance 21 of the offset can be selected as desired.

(41) FIG. 6 shows another embodiment where an offset 21 is provided between the port 13 and the end of the protrusion 11. However, in this embodiment, the first path 17 and the second path 18 are preferably parallel. In this embodiment, the protrusion 11 is preferably arranged and adapted so as to be kinked.

(42) Furthermore, as illustrated by FIG. 6, in an embodiment the protrusion 11 is arranged and adapted to extend into the third component 15. This advantageously can further reduce the number of leak points. The end of the protrusion 11 may extend beyond the third component 15 and/or may make a seal with a fourth component (not shown). Thus, in an embodiment, the protrusion 11 may be arranged to pass through a plurality of separate components of the mass spectrometer.

(43) Each of the preferred features of the protrusion 11 described above in relation to FIGS. 4-6 may be combined in any manner as desired. Thus, it will be appreciated that the preferred seal 1 comprising one or more protrusions 11 can advantageously be used to form a seal in wide range of situations and instrument geometries. For example, the fluid or gas lines that are connected via the seal 1 need not be parallel and/or aligned. Furthermore, the preferred seal 1 advantageously reduces the number of possible seal leak points that would otherwise be present.

(44) This is illustrated by FIG. 7, which shows a conventional gasket 31 as disclosed in GB-2471520 (Syms) and which is arranged between an electrospray ionisation source 32 and a mounting 33. In contrast with the preferred embodiment of the present invention, the gasket 31 is not provided with a protrusion. Thus, potential seal leak points exist, for example, at locations 34, 35. Furthermore, in order to form a seal, the channels through the electrospray ionisation source 32, the gasket 31 and the mounting 33 must be aligned and parallel, and the electrospray ionisation source 32 and the mounting 33 must be clamped together. The provision of one or more protrusions 11 in the preferred embodiment can avoid such potential leak points and can facilitate sealing in a wide variety of instrument geometries using a single seal.

(45) FIG. 8 shows in more detail the preferred seal 1 located in a mass spectrometer in accordance with a preferred embodiment. The main body of the preferred seal 1 is preferably arranged to form a gas tight and vacuum seal between the ion block 8 and the pumping block 9, as discussed above.

(46) The protrusion 11 is preferably arranged to pass through the body of the ion block 8, and to extend beyond the outer face of the ion block 8. A gap between the gas cone 12 and the ion block 8 is preferably bridged by the portion of the protrusion 11 that extends beyond the ion block 8. The top of the protrusion that sits above the face of the ion block 8 preferably contacts the gas cone 12 so as to form a gas tight and vacuum seal with the gas cone 12, preferably with only one contact face.

(47) The gas cone 12 is preferably held in place relative to the ion block 8 by a separate clamp 22.

(48) FIGS. 9 and 10 show the preferred mass spectrometer of FIG. 8, where the gas cone 12 and clamp 22 have been detached from the ion block 8 and pumping block 9.

(49) The arrangement of the preferred embodiment advantageously avoids the need to clamp the three parts (i.e. the ion block 8, the pumping block 9 and the gas cone 12) together and to provide a plurality of seals at each interface in order to effect a seal.

(50) The preferred embodiment therefore advantageously reduces the number of seals required as well as the number of potential leak points.

(51) Although the present invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the scope of the invention as set forth in the accompanying claims.