JPH07220674A - Gas introducing valve for mass spectrometry - Google Patents

Abstract

PURPOSE:To provide a gas introducing valve by which a throttle quantity and pressure of sample gas can be adjusted and the gas does not collide with an apparatus wall or the like when the sample gas is introduced to a mass spectrometer. CONSTITUTION:A direction control valve seat 40 is arranged in the middle of a gas introducing passage 38 by containing a valve body 36 having the straight gas introducing passage 38 observable straight toward a gas deriving end 36b from a gas introducing end 36a. A direction control valve 42 having an orifice 44 is installed on this direction control valve seat 40, and when the direction control valve 42 is inserted in or retreated from the gas introducing passage 38, a throttle condition or an opening condition can be easily obtained, and the gas introducing passage 38 can be constituted in both conditions out of a single introducing passage in a observable condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas introduction valve for mass spectrometry, particularly a mass spectrometer for analyzing a gas sample, and a sample gas generation chamber to be analyzed by the mass spectrometer. The present invention relates to a mass spectrometry gas introduction valve for introducing a sample gas into an ionization chamber of an analyzer at a desired pressure.

[0002]

2. Description of the Related Art FIG. 5 shows a schematic structure of a gas sample mass spectrometer, and particularly, a sample gas generating chamber 10 and a mass spectrometer 1.
2 and the internal structure of the mass spectrometer 12 in which the two are connected by the gas introduction valve 14 are shown in a broken state. The sample gas generation chamber 10 is provided with an outlet side flange 10a, and the mass spectrometer 12 is provided with an inlet side flange 12a. Then, the inlet side flange 14a at the gas inlet end and the outlet side flange 14b at the gas outlet end of the gas inlet valve 14 are connected to both the flanges 10a and 12a in an airtight state, and the gas sample in the sample gas generation chamber 10 is gas It is led to the mass spectrometer 12 through the introduction valve 14.

A well-known ion source 16 is provided in the mass spectrometer 12, and a sample gas is ionized in an ionization chamber 18 in the ion source 16 by being subjected to electron impact by an ionization electron beam. The passage of the sample gas in the mass spectrometer 12 is performed through the introduction pipe 20 and the connection pipe 22 extending from the entrance side flange 12a, and the ions generated in the ionization chamber 18 are connected to the main body of the ionization chamber 18 and the main ionization chamber 18. The ion beam accelerated by the acceleration voltage applied between the slit 24 and the main slit 24 is sent to the ion separation unit 26. As is well known, the ions separated by the ion separation unit 26 are detected by the ion detection unit 28, and mass analysis of the sample gas is performed.

What is important in such mass spectrometry is to guide the sample gas in the sample gas generation chamber 10 to the mass spectrometer 12 at a desired pressure, and the gas introduction valve 14 is
It is necessary not only to control the introduction and shielding of the sample gas, but also to perform the pressure adjustment.

For this reason, the conventional gas introduction valve is the first
A passage 101 and a second passage 102 are provided, and both passages 101 and 1
The pressure is adjusted by switching 02. The first passage 101 is used when the pressure of the sample gas is low, and its opening / closing is performed by the main valve 30. on the other hand,
The second passage 102 is used when the pressure of the sample gas is high, a depressurizing orifice 32 is provided in the passage, and the opening / closing of the second passage 102 is controlled by an orifice valve 34. Therefore, when the pressure of the sample gas is lower than a predetermined value, for example, 0.1 Pascal, the sample gas is guided to the mass spectrometer 12 through the first passage 101, and for this reason, the main valve 30 is opened, and Orifice valve 3
4 is closed. When the pressure of the sample gas is higher than 0.1 Pascal, the flow rate of the sample gas is reduced,
The main valve 30 is closed, while the orifice valve 34 is open. Therefore, in this high-pressure state, the sample gas is depressurized to a desired pressure through the orifice 32 and the mass spectrometer 1
You can lead to 2. Of course, the passage diameter of the orifice 32 is selected in advance to an appropriate value in order to perform the desired decompression according to the sample gas. Further, in order to completely shut off the sample gas generation chamber 10 from the mass spectrometer 12, both the main valve 30 and the orifice valve 34 are closed, and the sample gas generation chamber 1 is maintained while keeping the mass spectrometer 12 in a vacuum state.
It is possible to easily repair the inside of the gas generation chamber and the like by introducing the atmosphere into the atmosphere. For example, in the case of analyzing and measuring the atmospheric gas in a chemical reaction chamber in a semiconductor process chamber or the like, it is necessary to keep the mass spectrometer in a vacuum when exchanging substances in the reaction chamber. In such a case, The shutoff by the gas introduction valve is extremely effective.

As described above, the conventional mass spectrometric gas introduction valve requires at least two passages having different throttle amounts, and it is desirable that the gas introduction valve can be in a closed state.

FIG. 6 shows an example of another conventional gas introduction valve. The same or corresponding members as those in FIG. 5 are designated by the same reference numerals and the description thereof will be omitted. In the conventional example of FIG. 6, the passage that linearly connects the flanges 14a and 14b is formed as the second passage 102 including the orifice 32, while the detour is formed as the first passage 101. A main valve 30 and an orifice valve 34 are provided in each of the passages 101 and 102, as in the conventional example of FIG.

[0008]

However, in the above-described conventional gas introduction valve, since both passages having different throttle amounts are provided as separate passages, the sample gas passes through the gas introduction valve 14 at the time of passage. It is impossible to pass through the straight passage, but it is necessary to pass through the detour, and as a result, the sample gas may be deteriorated. That is, when the generated sample gas collides with the vessel wall before being guided to the ionization chamber 18 of the mass spectrometer 12, a phenomenon such as a chemical reaction on the vessel wall or adsorption to the vessel wall occurs. In particular, gas with strong adsorptivity such as moisture, active gas with strong reactivity such as halogen, or condensable gas component with low vapor pressure reacts sensitively when it collides with the instrument wall before measurement. As a result, the sample gas component changes. Therefore, the conventional gas introduction valve has a problem that an error occurs in the measurement result.

Therefore, in the prior art, it is desirable that the sample gas moves from the generation chamber 10 to the mass spectrometer 12 through a linearly extending guide passage. However, due to the above-mentioned reason, when the throttle amount is changed by a plurality of passages, There was a situation where it was not possible to satisfy such a linear outlook.

The present invention has been made in order to solve the above-mentioned conventional problems, and an object thereof is to improve the linear view of gas introduction even when the throttle of the sample gas is changed. To provide a gas introduction valve for mass spectrometry.

[0011]

In order to achieve the above object, the present invention provides a mass spectrometry gas introduction valve having a gas introduction end connected to a sample gas generation chamber and a gas introduction end connected to a mass spectrometer. In the above, the valve body is provided with a straight gas conduit that can be seen straight from the gas introduction end to the gas discharge end, and a switching valve seat is provided in the middle of the gas conduit, and the switching valve seat Is equipped with a switching valve for switching the gas conduit to an open state or a throttled state.

Further, according to the present invention, there is provided a gas analyzer for mass analysis, the gas introducing end of which is connected to the sample gas generating chamber and the gas outlet end of which is connected to the mass spectrometer.
A straight gas conduit that can be seen in a straight line from the gas inlet end to the gas outlet end is provided, and a switching valve seat is provided in the middle of the gas conduit, and the gas conduit is opened in the switching valve seat. A switching valve for switching between a closed state and a throttled state is mounted, and an opening / closing valve seat is further provided in the middle of the gas conduit, and an opening / closing valve for switching the gas conduit to open or closed is mounted on the opening / closing valve seat. It is characterized by being

[0013]

As described above, according to the present invention, the generated sample gas is guided to the mass spectrometer by a single linear gas passage provided in the valve body of the gas introduction valve, and the throttle amount is reduced. Alternatively, since the pressure is adjusted by the switching valve provided in the straight gas guide passage, the passage of the gas introduction valve may adversely affect the mass spectrometry result without passing through the detour as in the conventional case. The effect that there is no.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

First Embodiment FIG. 1 is a sectional view showing a first preferred embodiment of the gas introducing valve for mass spectrometry according to the present invention.

In FIG. 1, the gas introduction valve 14 includes a valve body 36, and the both flanges 14a and 14b described above are fixed to both ends of the body 36 in an airtight state. The valve body 36 includes both flanges 14a, 14
A straight gas conduit 38 is provided between the gas introduction end 36a of b and the gas extraction end 36b so as to be seen straight. In the embodiment, the gas conduit 38 is composed of a first conduit 38a having a large conductive diameter, which is provided with a switching valve described later, and a second conduit 38b having a small conductive diameter, which is also provided with an on-off valve described later. It

A switching valve seat 40 having a taper shape is provided in the middle of the first conduit 38a in a direction orthogonal to the axis of the gas conduit 38, and a switching valve 42 is mounted in the switching valve seat 40. Has been done. In the embodiment, the switching valve 42 is provided with the orifice 44, and when the switching valve 42 enters the switching valve seat 40 as shown in FIG. 1, the orifice 44 controls the throttle of the gas conduit 38. Can be controlled dynamically, and an iris state can be provided.

On the other hand, since the gas conduit 38 is opened, the switching valve 42 can be retracted from the switching valve seat 40, and the opening / closing mechanism 46 for this purpose is provided on the outer wall of the valve body 36. The opening / closing mechanism 46 includes a casing 48, and a support shaft 50 for axially moving the switching valve 42 is built in the casing 48. The support shaft 50 is kept airtight in the casing 48. A bellows 52 is provided between the bellows 52. The axial movement of the support shaft 50 is performed by a nut 54 and a push screw 56 fixed to the casing 48.
An engaging element 58 provided at the upper end of 6 engages with a locking seat 60 provided at the lower end of the support shaft 50, and when the push screw 56 rotates, the support shaft 50, that is, the switching valve 42 is rotated. It is possible to move only in the axial direction without moving. A switching handle 62 is provided at the lower end of the push screw 56, and the user can rotate the switching handle 62 to adjust the position of the switching valve 42 when adjusting the throttle of the passage.

In the first embodiment, an opening / closing valve seat 64 is provided in the second conduit 38b of the gas conduit 38, and an opening / closing valve 66 is attached to the opening / closing valve seat 64 to move the opening / closing valve 66 in the axial direction. The opening / closing of the second conduit 38b is controlled by.

At the upper end of the valve body 36, the on-off valve 6
An opening / closing mechanism 68 for moving 6 in the axial direction is provided,
Since the opening / closing mechanism 68 has the same configuration as the opening / closing mechanism 46, detailed description of each part will be omitted.

As described above, according to the first embodiment of the present invention, the pressure switching or throttling of the sample gas is performed only by the single straight gas passage 38 provided in the valve main body 36 and seen straight. The amount can be switched. That is, the feature of the present embodiment is that the gas conduit 38 is provided with the switching valve 42 for switching the open or throttled state of the gas conduit 38, and the throttle amount of the sample gas is limited only by the axial movement of the switching valve 42. Adjustments can be made. Similarly, according to the first embodiment, an opening / closing valve 66 for controlling the opening / closing of the gas conduit 38 is further provided in the single gas conduit 38, so that the gas introduction can be shielded or opened in a single manner. There is an advantage in that it can be performed using only the gas conduit 38 that can be seen straight from the end to the lead-out end.

The operation of the first embodiment will be described with reference to FIGS.

Similar to FIG. 1, FIG. 2 shows a state in which the switching valve 42 is in close contact with the switching valve seat 40. In this state, the orifice 44 is located at the central axis of the gas guide path 38, and the introduced gas is thereby introduced. The throttling is controlled mainly by the orifice 44, and this pressure can be reduced when the pressure of the sample gas is high.

As is apparent from FIG. 2, when the gas conduit 38 is in the throttled state, the switching valve 42 comes into close contact with the switching valve seat 40. At this time, therefore, a closed portion is generated at the tip of the switching valve seat 40. However, there is a possibility that the gas compression in the closed portion may prevent the switching valve 42 and the switching valve seat 40 from coming into close contact with each other. In the embodiment, however, the switching valve 42 has a gas leak hole connecting the closed portion and the gas conduit 38. By providing 42a, such inconvenience due to gas compression is prevented.

In the state of FIG. 2, the opening / closing valve 66 is in a state of being retracted from the opening / closing valve seat 64 by the opening / closing mechanism, and is in the open state in this state.

On the other hand, FIG. 3 shows a state in which the gas conduit 38 is opened by the switching valve 42. As described above, the opening / closing mechanism 46 moves the switching valve 42 downward in FIG. Thus, the switching valve 42 is completely retracted from the switching valve seat 40 and the gas conduit 38, and in this state, the throttle amount or pressure of the sample gas is the gas conduit 38, especially the second conduit 38b.
The sample gas can be efficiently guided to the mass spectrometer 12 when the gas pressure is low.

Even in the state of FIG. 3, the passage of the sample gas is no different from the throttled state of FIG. 2, and the straight gas guide path 38 which shares a straight line from the gas inlet end 36a to the gas outlet end 36b is shared. Therefore, it is possible to reliably prevent the inconvenience such as the alteration of the sample gas due to the curved detour as in the related art.

Embodiment 2 FIG. 4 shows a second preferred embodiment according to the present invention. In this second embodiment, only the switching valve is mounted on the gas conduit 38, and the second embodiment is the same as the first embodiment. The on-off valve has been removed.

As described above, according to the second embodiment, the gas conduit 38 cannot be shut off, but the throttle amount or the pressure can be adjusted according to the pressure of the sample gas, which is used for this type of application. It is also useful for a mass spectrometer or a mass spectrometer in which a gate valve or a straight valve corresponding to the opening / closing valve in the first embodiment is generally installed.

[0030]

As described above, according to the gas introduction valve of the present invention, when the sample gas is introduced into the mass spectrometer, the sample gas does not collide with the container wall or the like and the gas of the valve is directly introduced. The sample gas is guided in a straight line from the inlet end to the outlet end and can be guided to the ionization chamber without deterioration of the sample gas, which is extremely useful for accurate mass spectrometry. Further, according to the present invention, it is possible to extremely easily select either introducing the sample gas without depressurizing it or introducing it through the orifice for depressurizing by opening / closing the switching valve. It is possible to perform accurate and precise measurement even for an adsorptive gas such as, an active gas having a strong reactivity such as halogen, or a condensable gas component having a low vapor pressure.

Further, according to the present invention, the restriction amount of the orifice in the second conduit is changed by simply replacing the switching valve, and the gas introduction valve is provided between the sample gas generation chamber and the mass spectrometer. Even in the mounted state, there is an advantage that the changeover valve can be simply replaced.

[Brief description of drawings]

FIG. 1 is a first gas introduction valve for mass spectrometry according to the present invention.
It is a fragmentary sectional view showing an example.

FIG. 2 is a partial cross-sectional view showing a gas introducing action in a throttled state in the first embodiment of the present invention.

FIG. 3 is a partial cross-sectional view showing an open state in the first embodiment of the present invention.

FIG. 4 is a partial cross-sectional view showing a second preferred embodiment of the gas introducing valve for mass spectrometry according to the present invention.

FIG. 5 is a partially cutaway view showing a state in which a conventional gas introduction valve is mounted between a sample gas generation chamber and a mass spectrometer.

FIG. 6 is a cross-sectional view showing another conventional gas introduction valve.

[Explanation of symbols]

 10 sample gas generation chamber 12 mass spectrometer 14 gas introduction valve 36 valve body 36a gas introduction end 36b gas discharge end 38 gas conduit 40 switching valve seat 42 switching valve 44 orifice 46 opening / closing mechanism 64 opening / closing valve seat 66 opening / closing valve

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[Procedure amendment]

[Submission date] March 10, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

As described above, according to the second embodiment, the gas conduit 38 cannot be shut off, but the throttle amount or the pressure can be adjusted according to the pressure of the sample gas, which is used for this type of application. gate valve or straight valve corresponding to the opening and closing valve in the mass spectrometer or example 1 is also useful with the mass spectrometer that is already set.

Claims (2)

[Claims] 1. A mass spectrometry gas introduction valve having a gas introduction end connected to a sample gas generation chamber and a gas introduction end connected to a mass spectrometer, wherein the valve body has a straight line from the gas introduction end to the gas introduction end. A straight gas conduit that can be seen in a shape is provided, a switching valve seat is provided in the middle of the gas conduit, and a switching valve that switches the gas conduit to an open state or a throttled state is provided on the switching valve seat. A gas introduction valve for mass spectrometry, which is mounted. 2. A mass spectrometry gas introduction valve having a gas introduction end connected to a sample gas generation chamber and a gas introduction end connected to a mass spectrometer, wherein the valve body has a straight line extending from the gas introduction end to the gas introduction end. A straight gas conduit that can be seen in a shape is provided, a switching valve seat is provided in the middle of the gas conduit, and a switching valve that switches the gas conduit to an open state or a throttled state is provided on the switching valve seat. For mass spectrometric analysis, an opening / closing valve seat is further provided in the middle of the gas conduit, and an opening / closing valve for switching the gas conduit to open or close is mounted on the opening / closing valve seat. Gas introduction valve.