JP2003346703A - Mass spectrometer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mass spectrometer having a vacuum container of which, the inside is prevented from infiltration of dust or the like at a maintenance operation. <P>SOLUTION: A gap 9 is formed between the outside of a periphery sealing surface 3a of an opening part of a container 31 of the vacuum container 3 and a peripheral edge of an opening of a body of equipment 24 at a front panel 21 of the body of equipment 2, and the gap 9 is constructed so as to be closed when a door 8, closing an opening part of the container 31 and an opening of the body of equipment 24, is closed. A part of the air taken into the body of equipment 2 from outside is made to blow out frontward through the gap 9 by a blowing fan 5 for cooling when the door is opened for maintaining an ion source 32 of the vacuum container or the like. By the above, a kind of air curtain is formed at the front part of the container opening part 31 of the container, and the dust infiltrating from outside in the vacuum container 3 is prevented. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a mass spectrometer used for a GC / MS (gas chromatograph mass spectrometer), LC / MS (liquid chromatograph mass spectrometer), or the like.

[0002]

2. Description of the Related Art In general, a mass spectrometer ionizes a sample molecule or atom in an ion source and separates generated ions according to a mass number (mass / charge ratio) by a mass analyzer such as a quadrupole filter. , An ion detector. An ion source, a mass analyzer, an ion detector, and the like are disposed in a substantially hermetically sealed container, and the analysis is performed in a state where the inside of the container is maintained in a vacuum atmosphere by an attached vacuum pump.

In order to maintain high performance for a long time in such a mass spectrometer, regular maintenance is indispensable. For example, in an ion source, a residual gas component, a reactive gas component introduced into the ion source for chemical ionization, and the like adhere to the wall surface, so that the wall surface is contaminated with the analysis. As such contamination progresses, the ion generation conditions change and the amount of ion generation decreases, and as a result, analysis sensitivity may decrease, or the contamination components may appear as background noise and analysis accuracy may deteriorate. .
For this reason, it is necessary to perform disassembly and cleaning while the contamination of the ion source is light, and the frequency is generally quite high. Further, the filament for generating thermoelectrons used for electron impact ionization or the like is a consumable and needs to be replaced at an appropriate time.

In such maintenance work, it is necessary to open the vacuum container after returning the inside of the container to atmospheric pressure. Therefore, to facilitate maintenance work,
In a conventional mass spectrometer, a configuration in which a door for opening and closing a vacuum container is provided on a front surface of a housing is known.

[0005]

However, in the conventional mass spectrometer, during such maintenance work,
There is a possibility that dust may flow into the inside of the vacuum vessel, or the dust may adhere to the sealing surface of the flange at the opening of the vacuum vessel. If such foreign matter enters the inside of the vacuum container, it may cause background noise at the time of analysis, or may cause a failure of the pump by being sucked by the vacuum pump. On the other hand, if dust adheres to the sealing surface of the flange, the sealing performance is reduced when the vacuum container is sealed, and the degree of vacuum may not be easily increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to open a vacuum container to the outside and perform maintenance work on an ion source or the like, so that the vacuum container is inserted into the vacuum container. It is an object of the present invention to provide a mass spectrometer capable of effectively preventing inflow of dust and adhesion of dust to a sealing surface.

[0007]

Means for Solving the Problems and Effects The present invention made to solve the above problems has a box-shaped housing, and an ion source, a mass analyzer and an ion source arranged inside the housing. A mass spectrometer comprising: a vacuum vessel containing a detector; and a cooling air blower provided inside the casing and outside the vacuum vessel and sucking air from outside the casing to the inside. A container opening for opening the inside of the vacuum container, and a housing opening provided in the housing at a position substantially coincident with the container opening, wherein the container opening and the housing opening are provided. And a door body that integrally or independently closes, a gap is provided between the peripheral edge of the container opening and the peripheral edge of the housing opening, and the air is sucked into the housing by the blowing means. Blow at least a part of the air to the outside of the housing through the gap It is characterized in that the the like.

In the mass spectrometer according to the present invention, for example, in order to maintain the ion source in the vacuum container, the operator opens the door and turns the inside of the vacuum container to the atmosphere through the housing opening and the container opening. When opened, the air flow by the blowing means blows outward from a gap around the container opening. Since the air flow blown out from the gap flows so as to cover the opening of the container, it functions as a kind of air curtain, and separates the inside and the outside of the vacuum container. For this reason, dust that tends to flow into the vacuum chamber from the outside and extremely lightweight debris that floats in the air are not blocked by the air curtain and enter the vacuum chamber. Does not adhere to the sealing surface.

Therefore, according to the mass spectrometer according to the present invention, even when the inside of the vacuum vessel is opened, foreign matter hardly flows into the vacuum vessel, so that background noise due to such foreign matter during subsequent analysis is reduced. . In addition, failure of a pump or the like that evacuates the vacuum from the inside of the vacuum vessel can be reduced. In addition, when the door is closed, the sealing performance of the vacuum container is improved, the degree of vacuum can be quickly increased, the analysis efficiency can be improved, and the running cost can be reduced.

Furthermore, since the air flow forming the air curtain is generated by the blowing means originally provided for cooling the apparatus, it is not necessary to add a special member or the like, and it is easy. In addition, the above-described effect can be obtained at very low cost.

In the mass spectrometer according to the present invention, preferably, when the door is closed, the gap is closed by the door. Thus, when the door is closed for analysis or the like, the above-mentioned gap is closed, so that the outside air taken into the housing by the air blowing means flows so as to appropriately cool various members in the housing. . Therefore, the cooling effect, which is the original purpose of the blowing means, is not hindered. On the other hand, when the door is opened for maintenance or the like, the gap is formed, and the air curtain as described above is formed in front of the container opening to achieve the above-described effect.

The maintenance work can be efficiently performed by the door body integrally closing the container opening and the housing opening.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A mass spectrometer according to one embodiment of the present invention will be described below with reference to FIGS.
1 and 2 are external perspective views of the mass spectrometer of the present embodiment. FIG. 1 shows a state where the door is closed, and FIG. 2 shows a state where the door is opened. FIG. 3 is a side longitudinal sectional view of a main part of the mass spectrometer of the present embodiment, in which (A) shows a state in which a door is closed,
(B) is a state where the door is opened. FIG. 4 is a schematic front view of the mass spectrometer of the present embodiment.

Box-shaped housing 2 forming the outer shape of the mass spectrometer 1
Inside, a vacuum vessel 3, a turbo-molecular pump 4 for evacuating the vacuum vessel 3, a blower fan 5 for cooling each member inside the housing 2 including the pump 4, and the like are arranged. ing. One side plate 22 of the casing 2 is provided with an intake opening 6 for taking in outside air into the casing 2 when the blower fan 5 is operated, and an exhaust opening 7 for discharging the air inside the casing 2 to the outside. Is provided on the back plate 23 of the housing 2.

The vacuum container 3 has a container opening 31 on a surface facing the front plate 21 of the housing 2.
In the front plate 21 of the housing 2, a housing opening 24 which is slightly larger than that is formed. The front plate 21 has the container opening 3 together with the housing opening 24.
1 is also provided with an openable and closable door 8 which is simultaneously closed. When the door 8 is closed, a sealing member such as an O-ring for maintaining airtightness is provided on the inner surface of the door 8 which contacts the sealing surface 3a of the flange at the front edge of the vacuum vessel 3.

Inside the vacuum vessel 3, an ion source 32 is disposed at a position closest to the vessel opening 31 as a main component for mass spectrometry. Although not shown, an ion lens, a quadrupole filter (mass analyzer), an ion detector, and the like are arranged in order. Therefore, when the door 8 is opened, the ion source 32 is located immediately inside the container opening 31.
The work for the ion source 32 that is most frequently maintained is facilitated.

As shown in FIG. 3 and FIG.
4 is slightly larger than the container opening 31, and the container opening 31 is located at a position slightly retreated from the housing opening 24, so that around the sealing surface 3 a of the front edge flange of the vacuum container 3, A gap 9 communicating the space inside the casing 2 and outside the vacuum vessel 3 and the outside of the casing 2 over the entire circumference.
Are formed. Then, as shown in FIG.
When the door 8 is closed, the door 8
Are also configured to be substantially closed.

At the time other than the maintenance work including the time of the analysis, the vacuum vessel 3 is sealed by the door 8, as shown in FIGS. 1 and 3A. At this time, the gap 9 is also closed by the door 8 as described above. When the blower fan 5 operates in this state, the air outside the housing 2 flows into the housing 2 through the intake opening 6. Therefore, the air pressure inside the housing 2 is slightly higher than the atmospheric pressure outside the housing 2,
The air inside the housing 2 is discharged to the outside of the housing 2 through the exhaust opening 7 by the pressure difference. As a result, an air flow that enters through the intake opening 6 and is exhausted through the exhaust opening 7 is generated inside the housing 2, so that the turbo molecular pump 4 and the like are deprived of heat by being exposed to this air flow, Excessive rise in the temperature inside the housing 2 is prevented.

When an operator performs maintenance work on the ion source 32 and the like, the operation of the turbo molecular pump 4 is stopped, the inside of the vacuum vessel 3 is returned to substantially atmospheric pressure, and the door 8 is opened to open the vacuum vessel 3. Open the interior of the to the atmosphere. Door 8
Is opened, as shown in FIG. 2 and FIG.
Also open. Then, in addition to the above-described exhaust opening 7, the gap 9 also serves as an air outlet, so that a part of the air introduced into the housing 2 by the operation of the blower fan 5
From the front. By this air flow, a kind of air curtain is formed in front of the container opening 31. Since the inside of the vacuum vessel 3 has no escape path for air, the airflow blown out from the gap 9 may slightly flow into the vacuum vessel 3 immediately after the door 8 is opened, but thereafter flows into the vacuum vessel 3. It is exhaled forward without doing.

This air flow thus acts very effectively as an air curtain. That is, dust and the like floating in the atmosphere, which are shielded by the air curtain, are prevented from entering the vacuum container 3 and adhering to the sealing surface 3 a of the front edge flange of the vacuum container 3. Furthermore, when the operator performs maintenance work on the ion source 32 and the like, the operator inserts his / her own hands and various tools into the vacuum vessel 3. Since the tools pass through the air curtain, there is also an advantage that the attached dust and the like are blown off and the risk of being brought into the vacuum vessel 3 is reduced.

As described above, in the mass spectrometer 1 according to the present embodiment, when performing maintenance work inside the vacuum vessel 3,
Foreign matter such as dust hardly flows into the vacuum container 3. Therefore, it is possible to prevent such foreign substances from appearing as background noise at the time of the next analysis, to perform high-accuracy analysis, and to prevent the foreign substances from being sucked into the turbo molecular pump 4 and causing a failure. it can.

Since dust can be prevented from adhering to the sealing surface 3a of the front edge flange of the vacuum vessel 3, the door 8
When the container is closed, the hermeticity of the vacuum vessel 3 is good,
The degree of vacuum can be quickly increased. Furthermore, case 2
Since the airflow from the blower fan 5 for cooling the inside of the device is used to form an air curtain, the cost of the apparatus does not increase significantly to add the above-described function, but rather the conventional device. The above-described effect can be obtained with almost no increase in cost for the above-described device.

In the above description, the gap 9 serving as an air outlet is provided on the entire periphery of the container opening 31. However, it is apparent that the same effect can be obtained even if it is not necessarily the entire periphery but a part. It is. Further, the above embodiment is merely an example of the present invention, and it is apparent that modifications and changes can be appropriately made within the scope of the present invention.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a mass spectrometer according to one embodiment of the present invention.

FIG. 2 is an external perspective view showing a state where a door is opened in the mass spectrometer of the present embodiment.

FIG. 3 is a side longitudinal sectional view of a main part of the mass spectrometer of the present embodiment, in which (A) shows a state in which a door is closed, and (B) shows a state in which the door is opened.

FIG. 4 is an external front view of the mass spectrometer of the present embodiment with a door opened.

[Explanation of symbols]

1. Mass spectrometer 2. Housing 21 Front plate 22 ... side plate 23 ... back plate 24 ... Case opening 3. Vacuum container 3a ... flange sealing surface 31 ... Container opening 32 ... Ion source 4: Turbo molecular pump 5… Blower fan 6 ... intake opening 7 ... Exhaust opening 8 ... door 9 ... Gap

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01J 49/24 H01J 49/24

Claims (3)

[Claims] 1. A box-shaped housing, a vacuum container disposed inside the housing and containing an ion source, a mass analyzer, and an ion detector, and inside the housing and outside the vacuum container. And a cooling air blower for sucking air from outside to inside of the casing, wherein the vacuum vessel is provided with a vessel opening for opening the inside thereof, and The body is provided with a housing opening at a position substantially coinciding with the container opening, and a door is provided for closing the container opening and the housing opening integrally or independently, and a peripheral edge of the container opening. A gap is provided between the casing and the peripheral edge of the casing opening, and at least a portion of the air sucked into the casing by the blowing means is blown out of the casing through the gap. A mass spectrometer characterized in that: 2. The mass spectrometer according to claim 1, wherein when the door is closed, the gap is closed by the door. 3. The mass spectrometer according to claim 1, wherein the door body integrally closes the container opening and the housing opening.