Mass spectrometer

Abstract

A mass spectrometer (10) includes a housing (19) that houses a plurality of devices including a mass analyzer (110) including an ionization unit, a mass separation unit, and an ion detection unit, a first heat generation device (11), and a second heat generation device (12) which has an allowable maximum temperature lower than that of the first heat generation device (11) or an allowable temperature variation amount smaller than that of the first heat generation device (11), an intake port (14) of the housing (19) which is provided at a position closer to the second heat generation device (12) with respect to the first heat generation device (11), and an exhaust fan (15) of the housing (19) which is provided at a position farther from the second heat generation device (12) with respect to the first heat generation device (11).

Claims

1. A mass spectrometer comprising: a housing configured to house a plurality of devices including a mass analyzer including an ionization unit, a mass separation unit, and an ion detection unit; a first heat generation device which is one of the devices; a second heat generation device which is one of the devices, the second heat generation device having an allowable maximum temperature lower than an allowable maximum temperature of the first heat generation device or an allowable temperature variation amount smaller than an allowable temperature variation amount of the first heat generation device and being disposed at a position higher than a position of the first heat generation device; an intake port, of the housing provided at a position closer to the second heat generation device with respect to the first heat generation device and disposed at a position lower than a position of the second heat generation device; and an exhaust fan, of the housing provided at a position farther from the second heat generation device with respect to the first heat generation device and disposed at a position higher than the position of the second heat generation device.

2. The mass spectrometer according to claim 1, wherein the second heat generation device does not include a fan for local cooling.

3. The mass spectrometer according to claim 1, wherein an opening area of the intake port is 0.3 to 7 times an opening area of the exhaust fan.

4. The mass spectrometer according to claim 1, wherein the mass spectrometer includes a plurality of the intake ports, and a second heat generation device is disposed, for each of the plurality of the intake ports, at a position, in the housing, closer to the intake port with respect to the first heat generation device.

5. The mass spectrometer according to claim 4, wherein a sum of opening areas of the plurality of intake ports is 0.3 to 7 times an opening area of the exhaust fan.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIGS. 1A and 1B are a plan view and a side view, respectively, showing an arrangement of a mass analyzer, a turbo molecular pump, and a power supply in a first embodiment of a mass spectrometer according to the present invention.

(2) FIG. 2 is a schematic configuration diagram showing the mass analyzer included in the mass spectrometer of the first embodiment.

(3) FIG. 3 is a plan view of a temperature distribution in a housing obtained by calculation for the mass spectrometer of the first embodiment.

(4) FIG. 4 is a side view of air flow velocity distribution obtained by calculation for the mass spectrometer of the first embodiment.

(5) FIG. 5 is a plan view showing an arrangement of a mass analyzer, a turbo molecular pump, and a power supply in a second embodiment of the mass spectrometer according to the present invention.

DESCRIPTION OF EMBODIMENTS

(6) Embodiments of a mass spectrometer according to the present invention will be described with reference to FIGS. 1 to 5.

(7) As shown in FIGS. 1A and 1B, a mass spectrometer 10 of a first embodiment includes a mass analyzer 110, a turbo molecular pump 121 that is a vacuum pump, a power supply 122, and a housing 19 that houses them.

(8) As shown in FIG. 2, the mass analyzer 110 includes a vacuum chamber 117 in which an ion source 111, a quadrupole mass filter 112, a collision cell 113, an ion trap 114, a time-of-flight mass separator 115, and an ion detector 116 are arranged. The ion source 111 ionizes various compounds contained in the sample. The quadrupole mass filter 112 passes only precursor ions having a specific mass-to-charge ratio specified in advance. The collision cell 113 cleaves precursor ions and includes an ion guide 1131 in its inside. The ion trap 114 captures a product ion produced by cleavage and a precursor ion that has not been cleaved, and then ejects them in a packet form, and includes a ring electrode 1141 and a pair of end cap electrodes 1142 and 1143 that is provided with the ring electrode interposed between them. The time-of-flight mass separator 115 applies a certain acceleration energy to ions and flies the ions a certain distance to cause the ion detector 116 to detect the ions, so that it calculates the mass-to-charge ratio of the ions from the time required for the flight. The time-of-flight mass separator 115 includes an expulsion electrode 1151 and a grid electrode 1152 that accelerate ions in a direction (downward) perpendicular to the traveling direction so far, and a reflective electrode (reflectron) 1153 for reflecting the accelerated ions after flying the ions a predetermined distance. The power supply 122 is connected to respective electrodes included in the quadrupole mass filter 112, the collision cell 113, the ion trap 114, the time-of-flight mass separator 115, and the ion detector 116, the ion detector 116, and the like, and power is supplied to respective components. The vacuum chamber 117 is connected to the turbo molecular pump 121, and its inside is maintained at a high vacuum. The mass analyzer 110 shown here is an example, and various mass analyzers can be used in the present invention.

(9) As shown in FIGS. 1A and 1B, the housing 19 has a rectangular parallelepiped shape, an intake port 14 is also provided in an intake port installation face 191 that is one of the four side surfaces of the rectangular parallelepiped, and a plurality of exhaust fans 15 is arranged on an exhaust fan installation face 192 side by side so as to occupy most of the exhaust fan installation face 192, in the width direction, that is a side surface facing the intake port installation face 191. The opening area of the intake port 14 is preferably 0.3 to 7 times the opening area of the exhaust fans 15, and is the same as the opening area of the exhaust fans 15 in the first embodiment.

(10) Usually, a commercially available turbo molecular pump is provided with a fan for cooling itself. However, the turbo molecular pump 121 used in the mass spectrometer 10 of the first embodiment is not provided with a fan, and it is cooled only by the cooling mechanism that combines the intake port 14 and the exhaust fans 15 provided in the housing 19.

(11) The exhaust fans 15, the power supply 122, the turbo molecular pump 121, a device other than the turbo molecular pump 121 and the power supply 122 (a first heat generation device 11 described later), the intake port 14 are arranged from top to bottom with respect to the height direction.

(12) The mass spectrometer 10 of the first embodiment operates the exhaust fans 15 to have a negative pressure inside of the housing 19, whereby external air is introduced into the housing 19 from the intake port 14. The cooling mechanism that combines the intake port 14 and the exhaust fans 15 generates air flow in the housing 19 more easily than the cooling mechanism that combines the intake fan and the exhaust port, and cools the interior of the housing 19 evenly.

(13) The turbo molecular pump 121 and the power supply 122 correspond to a heat generation device whose allowable maximum temperature is lower than that of another device (the first heat generation device 11) in the mass spectrometer 10 of the first embodiment or that is sensitive to ambient temperature variations, that is, the above second heat generation device. Hereinafter, the turbo molecular pump 121 and the power supply 122 are collectively referred to as a “second heat generation device 12”. The intake port 14 is provided at a position closer to the second heat generation device 12 with respect to the first heat generation device 11, and the exhaust fans 15 is provided at a position farther from the second heat generation device 12 with respect to the first heat generation device 11. Therefore, the air introduced into the housing 19 from the intake port 14 passes through the second heat generation device 12 at a wind speed faster than that at the position of the first heat generation device 11, so that the second heat generation device 12 can be efficiently cooled.

(14) In the mass spectrometer 10 of the first embodiment, the second heat generation device 12 is disposed at a position higher than positions of the intake port 14 and the first heat generation device 11, and further, the exhaust fans 15 is disposed at a position higher than positions of the first heat generation device 11 and the second heat generation device 12, so that air that has been warmed and lightened by cooling the second heat generation device 12 passes above the first heat generation device 11 and is discharged from the exhaust fans 15 to the outside of the housing 19. Therefore, the first heat generation device 11 is not exposed to the air warmed by the second heat generation device 12, and the temperature rise of the first heat generation device 11 can be more effectively prevented. The first heat generation device 11 is cooled by the passage of air that has been introduced from the intake port 14 and has passed below the second heat generation device 12.

(15) For the mass spectrometer 10 of the first embodiment, the temperature distribution and the air flow velocity distribution in the housing 19 were calculated. For the results, FIG. 3 shows the temperature distribution in plan view and FIG. 4 shows the air flow velocity distribution in side view. The temperature is high (“H” in FIG. 3) or relatively higher (“MH” in FIG. 3) in the turbo molecular pump 121 and the power supply 122, and is relatively low (“ML” in FIG. 3) around the turbo molecular pump 121 and the power supply 122, in the region near the exhaust fans 15 which is air downstream of the power supply 122, and in the region where the first heat generation device 11 exists, and is low in the other regions (“L” in FIG. 3). In the entire housing 19, the temperature exhibits a distribution that is nearly uniform except for the position where the second heat generation device 12 is disposed. The air flow velocity in the vicinity of the intake port 14 and the exhaust fans 15 is higher than that in the other positions. In particular, the vicinity of the intake port 14 can be cooled with air before being heated by the other heat generation devices, so that the above devices are arranged to be suitable for cooling the second heat generation device 12 disposed closer to the intake port 14 with respect to the first heat generation device 11.

(16) A second embodiment of the mass spectrometer according to the present invention will be described with reference to FIG. 5. A mass spectrometer 10A of the second embodiment includes the turbo molecular pump 121 and the power supply 122 (the second heat generation device 12) similar to those of the mass spectrometer 10 of the first embodiment, and the first heat generation device 11 which is another device which are housed in a rectangular parallelepiped housing 19A. Two intake ports, that is, the first intake port 141 and the second intake port 142, are provided, at the same height, in an intake port installation face 191A, which is one of the four side faces of the housing 19A. The turbo molecular pump 121 is disposed at a position closer to the first intake port 141 with respect to the first heat generation device 11 and the power supply 122. On the other hand, the power supply 122 is disposed at a position closer to the second intake port 142 with respect to the first heat generation device 11 and the turbo molecular pump 121. The exhaust fans 15 similar to those of the mass spectrometer 10 of the first embodiment are provided in an exhaust fan installation face 192A that is a side face, of the housing 19A, that faces the intake port installation face 191A. The positional relationship in the height direction between the first heat generation device 11, the turbo molecular pump 121, the power supply 122, the intake ports (the first intake port 141 and the second intake port 142), and the exhaust fans in the mass spectrometer of the second embodiment is the same as that in the mass spectrometer 10 of the first embodiment.

(17) The area of the first intake port 141 is larger than the area of the second intake port 142. The sum of the areas of the first intake port 141 and the second intake port 142 is preferably 0.3 to 7 times the opening area of the exhaust fans 15, and is the same as the opening area of the exhaust fans 15 in this embodiment.

(18) In the mass spectrometer 10A of the second embodiment, the first intake port 141 is provided at a position closer to the turbo molecular pump 121 with respect to the first heat generation device 11, and the second intake port 142 is provided at a position closer to the power supply 122 with respect to the first heat generation device 11. For this reason, the air introduced into the housing 19 from the first intake port 141 passes through the turbo molecular pump 121 at a wind speed faster than that at the position of the first heat generation device 11, and the air introduced into the housing 19 from the second intake port 142 passes through the power supply 122 at a wind speed faster than that at the position of the first heat generation device 11, so that the turbo molecular pump 121 and the power supply 122 that are the second heat generation device 12 can be efficiently cooled. In addition, since the first intake port 141 has a larger area than the second intake port 142, the turbo molecular pump 121 having a larger heat value than the power supply 122 is supplied with a larger amount of air, thereby being more efficiently cooled.

(19) Needless to say, the present invention is not limited to the above-described embodiments, and various modifications are possible.

REFERENCE SIGNS LIST

(20) 10, 10A . . . Mass Spectrometer 11 . . . First Heat Generation Device 110 . . . Mass Analyzer 111 . . . Ion Source 112 . . . Quadrupole Mass Filter 113 . . . Collision Cell 1131 . . . Ion Guide 114 . . . Ion Trap 1141 . . . Ring Electrode 1142 . . . End Cap Electrode 115 . . . Time-Of-Flight Mass Separator 1151 . . . Expulsion Electrode 1152 . . . Grid Electrode 116 . . . Ion Detector 117 . . . Vacuum Chamber 12 . . . Second Heat Generation Device 121 . . . Turbo Molecular Pump 122 . . . Power Supply 14 . . . Intake Port 141 . . . First Intake Port 142 . . . Second Intake Port 15 . . . Exhaust Fan 19, 19A . . . Housing 191, 191A . . . Intake Port Installation Face 192, 192A . . . Exhaust Fan Installation Face 192A . . . Exhaust Fan Installation Face