JPS633085Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an aperture plate exchange mechanism suitable for use in a mass spectrometer equipped with an atmospheric pressure ionization (API) ion source.

In a mass spectrometer using an API ion source, it is necessary to introduce ions produced by an ion source at atmospheric pressure into the mass spectrometer in a high vacuum. A configuration in which plates are arranged is known. In the figure, 1 is
API ion source, 2 is a quadrupole mass spectrometer that performs mass spectrometry on ions generated by the API ion source, 3 is a diffusion pump that exhausts the inside of the mass spectrometer, 4 is a high vacuum mass spectrometer and atmospheric pressure 5 is a rotary pump that exhausts the inside of the connection chamber 4, 6 is an aperture plate provided between the connection chamber 4 and the ion source 1, and 7 is an intermediate connection chamber that connects the ion sources from the atmosphere side. This is a skimmer installed between the connection chamber 4 and the mass spectrometer to reduce solvent and the like.

In such a mass spectrometer, the diameter of the aperture made in the aperture plate 6 to maintain the pressure difference is extremely small, and clogging with samples is likely to occur, so the aperture plate must be removed frequently for cleaning or replacement. It needed to be removed, and in the past, the vacuum pump had to be stopped each time the work was done.
As a result, it takes a long time for the device to return to high vacuum again after replacement or cleaning.

This invention was made in view of this point,
To provide a mechanism that allows an aperture plate to be replaced without breaking the vacuum.

The present invention includes a base having an opening, two O-rings arranged on the surface of the base so as to double surround the opening, and an aperture plate having an opening and attached to seal the opening. The retaining plate is slidably brought into close contact with the base body through the O-ring, and the opening of the retaining plate is connected between the two O-rings so that two O-rings can be attached at the same time.
It is characterized by a space that does not cover the ring. An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 2 is a sectional view showing the configuration of an embodiment of the present invention, and the same components as in FIG. 1 are given the same numbers. In the figure, 8 is a partition wall that partitions the connection chamber 4 and the mass spectrometer, and a skimmer 7 is attached to it. Reference numeral 9 denotes a partition wall that partitions the connection chamber 4 and the API ion source, and has an opening 10 through which ions pass. On the surface of the partition wall 9 on the ion source side, a third
As shown in the figure, a double groove is provided surrounding the opening 10, and O-rings 11 and 12 are embedded in the grooves, respectively. Reference numeral 13 denotes a holding plate for holding the aperture plate, which has an opening 14 through which ions pass, and the aperture plate 6 is attached to the holding plate 13 by a retaining ring 15 so as to seal the opening 14.
The holding plate 13 is disposed in close contact with the partition wall 9 and is slidable in the direction of the arrow while maintaining the close contact by a slide mechanism (not shown).

In the above configuration, the partition wall 9 and the retaining plate 13
Since the connection chamber 4 and the ion source are sealed by the O-ring 11, the connection chamber 4 and the ion source communicate with each other through a small diameter aperture made in the aperture plate 6, and the connection chamber 4 is evacuated by the rotary pump 5. A pressure difference between the ion source and the atmospheric pressure ion source is maintained by the aperture. Ions generated in the API ion source pass through the aperture into the connection chamber 4.
and further introduced into the mass spectrometer via the skimmer 7.

If the aperture plate becomes clogged due to long-term use and the aperture plate needs to be replaced, move the holding plate 13 in the direction of the arrow using the slide mechanism to bring it into the state shown in Fig. 4. Since the space between them is partitioned by the holding plate 13 and the O-ring 11, gas will not flow into the connection chamber 4 from the ion source side, and the aperture plate 6 can be replaced while the vacuum pump and the like remain in place. During the transition from the state shown in FIG. 2 to the state shown in FIG. 4, when the opening 14 of the holding plate 13 passes over the O-ring 11, the seal by the O-ring 11 is lost, but since the O-ring 12 is provided on the outside, , gas does not flow into the connection chamber 4 from the ion source side.

In addition, between the O-ring 11 and the O-ring 12,
It goes without saying that at least a space is required in the area where the aperture plate 6 moves so that the opening 14 does not overlap the O-rings 11 and 12 at the same time.

In the embodiment described above, the O-ring 12 is fixed in a groove provided in the partition wall 9 serving as the base, but it may be held from the outside by a plate thinner than the O-ring.

The present invention can be implemented even in an apparatus in which the connection chamber 4 as in the above-mentioned example does not exist and ions are directly introduced into the mass spectrometer through an aperture. It is widely applicable to devices that partition two areas.

As described in detail above, according to the present invention, an aperture plate exchange mechanism is realized with a simple configuration that allows an aperture plate to be exchanged without breaking the vacuum.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a conventional example, FIGS. 2 and 4 are cross-sectional views showing the configuration of an embodiment of the present invention, and FIG. 3 is a diagram for explaining the arrangement of two O-rings. be. 1: API ion source, 2: quadrupole mass spectrometer,
4: Intermediate connection chamber, 6: Aperture plate, 9: Partition wall,
10, 14: Opening, 11, 12: O ring, 1
3: Holding plate.

Claims (1)

[Scope of utility model registration request] a base body having an opening; two O-rings arranged on the surface of the base body so as to double surround the opening; and a holding plate having an opening and having an aperture plate attached thereto to seal the opening. The retaining plate is slidably brought into close contact with the base body via the O-ring, and the opening of the retaining plate is prevented from being exposed to the two O-rings at the same time between the two O-rings. An aperture plate exchange mechanism characterized by a space provided.