JPS631541B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to mass spectrometer pumping and leak methods.

The analysis section of the mass spectrometer is evacuated to 10 ^-6 to ^{10 -7} Torr in order to efficiently carry out ion flight and mass dispersion. There are oil diffusion pumps, ion pumps, molecular pumps, etc. as vacuum pumps to obtain a vacuum in this region, but due to the price, oil diffusion pumps (hereinafter referred to as
DP) is the most commonly used. On the other hand, in a GC-MS device that combines a gas chromatograph (hereinafter abbreviated as GC) and a mass spectrometer (hereinafter referred to as MS), it is difficult to maintain the analysis section at the above vacuum level because the carrier gas flows into the MS from the GC. Therefore, differential exhaust is used as shown in Figure 1. GC−
MS devices also often have a direct sample introduction device 3 in addition to the GC 1, so as shown in FIG.
It has multiple exhaust systems, including an exhaust system 6 for the analysis section 4 and an exhaust system 7 for the analysis section 4. DP is widely used because it is advantageous in terms of price, but it takes time for it to become operational after the power is turned on, and for it to stop operating after the power is turned off, and back diffusion of DP oil can contaminate high vacuum chambers and vacuum gauges. It has disadvantages such as causing In particular, contamination caused by erroneous operation is significant. In addition to the exhaust system described above, Fig. 2 has an independent pre-evacuation system 8, and when leaking from the ion source section 2 and analysis section 4, the DP is stopped using the evacuation system shown in Fig. 1. By simply closing the high-vacuum side shutoff valve, you can independently perform leakage and preliminary evacuation from the preliminary evacuation system while leaving each DP evacuation system operating, which has the advantage of saving time. Since the number of exhaust systems increases, it is not only expensive but also complicated to operate.

The present invention eliminates the drawbacks of the prior art by performing leakage and preliminary evacuation of each vacuum chamber directly through a common leak hole and exhaust system provided in the sample introduction section (hereinafter abbreviated as DI section). and provide leakage methods.

FIG. 3 shows the exhaust system of a mass spectrometer for carrying out the method of the present invention. DI part 3,
Each vacuum chamber of the ion source section 2 and the analysis section 4 is equipped with a low vacuum gauge 14 and a high vacuum gauge 15 so that a wide range of pressure can be detected. Further, the DI section 3 has a common leak hole 22, and leakage from each vacuum chamber is performed through this leak hole. Now, considering the case where the analysis section 4 leaks, first, the high vacuum gauge 15 is shut off in response to a leak command from the analysis section 4, the valve B17, the valve C18, and the valve D19 are closed, and the common leak hole 22 is opened. Low vacuum gauge 14 indicates that the pressure has increased due to a leak.
Then, the high vacuum gauge 15 of the ion source section 2 and the ion source power supply are shut off, the valve A16 is closed, and the valve B17 is opened. Since the common leak hole 22 is open, the ion source leaks and the low vacuum gauge 1
Detected by 4. The leak detection signal similarly opens the valve E20 to leak the analysis section 4.
A leak command can be issued by a switch. FIG. 4 shows an embodiment of a control circuit that performs this leakage operation. 23, 24, 25 are DI respectively
operation switch for the ion source section, ion source section, and analysis section.
When the NC contact is set to the vacuum evacuation state, when one of the switches becomes the NO contact, so-called leak state command, the level of the output point B of the gate circuit 27 changes as shown in FIG. 5, and the valve control circuit 28 is operated, and the valve B17 , C18, and D19, and the high vacuum gauge circuit 29 is cut off. The signal at point B is timer T ₁ 3
Input to 0. Timer _T1 is like output point C
T After ₁ hour, the leak valve control circuit 31 is activated to start leaking. Next, the low vacuum gauge 26 detects a leak state as at the output point D, and issues a leak end command 33 as the output point F via the timer T ₂ 32. This completes the leak of the DI part. Although not shown, the state of the operation switch 23 can be judged and the ion source can be leaked when it matches the DI leak end command. At this time, valve A16 is closed and valve B17 is opened. Similarly, the state of the operation switch 24 can be determined, and when it matches the ion source leak termination command, the analyzer can be caused to leak. At this time, the valve 21 is closed,
Valve E20 is opened. On the other hand, the status can be displayed by detecting the pressure of each vacuum gauge and the position of the operating switch. Figure 6 shows an example of the display circuit, in which the operation switch 34 is connected from the NC side.
When set to the NO side, the gate circuit 35 passes the output of the oscillator 36 and causes the display element 37 to blink at the oscillation frequency of the oscillator 36. On the other hand, when a leak or exhaust end signal is received from 38, the display element can be turned on. The levels of each part during this time are shown in FIG. As described above, it is possible to enter the leak state while displaying the status by commands from the operation switch.
Next, the case where vacuum evacuation is performed again will be described.

In FIG. 3, when the analysis section 4 is in a leak state and is to be evacuated, preliminary evacuation is performed by the rotary pump RP exhaust system 12 via the ion source section 2 and the DI section 3. The degree of vacuum in the analysis section is detected by the low vacuum gauge 26, and when the predetermined pressure is reached, the valve E is activated as shown in the output L.
20 and open valve F21 like output M.
Switch to DP exhaust system 13. FIG. 8 shows an embodiment of this exhaust circuit, in which 39 is a gate circuit, 40 is a valve E control circuit, 41 is a timer T ₃ , and 42 is a valve F control circuit. Figure 9 shows the levels of each part. The same applies when evacuating the ion source section 2.
After the rotary pump RP exhaust system 12 performs preliminary exhaust through the DI section 3, the system is shut off, and the exhaust system 11 performs main exhaust. The same goes for exhausting the DI section.
After preliminary evacuation with the rotary pump RP exhaust system 12, this system is shut off, and the valve 18 is opened to exhaust the exhaust system 1.
Main exhaust is performed by 1. Thus, the ion source section 2,
The DI section 3 and the analysis section 4 can be fully evacuated independently of each other.

By configuring as described above, according to this embodiment, the drawbacks of the conventional system can be eliminated and the following features can be obtained.

(1) Leak or exhaust can be performed with a single switch, greatly improving operability.

(2) The structure can be simplified because the entire device can be leaked with just one leak hole.

(3) Equipped with a function that makes decisions based on switch commands and pressure detection, eliminating erroneous operations.

(4) To display leak and exhaust operating status,
Each status can be easily understood.

(5) Leak and exhaust operations can be unmanned, resulting in labor savings.

There are performance improvements such as

According to the present invention, the evacuation time is shortened, and preliminary evacuation and leakage of the DI section, ion source section, and analysis section can be performed in series, making the entire device inexpensive and easy to operate. become.

[Brief explanation of the drawing]

1 and 2 are block diagrams of a conventional mass spectrometer exhaust system, and FIG. 3 is a block diagram of an embodiment of a mass spectrometer exhaust system for carrying out the method of the present invention. FIG. 4 shows an example of the leak circuit, FIG. 5 shows the levels of each part of the leak circuit, FIG. 6 shows an example of the display circuit, and FIG. 7 shows the display circuit. The levels of each part of the circuit are shown. FIG. 8 is an example of an exhaust circuit, and FIG.
The diagram shows the levels of each part of the exhaust circuit. 2...Ion source section, 3...Direct sample introduction section, 4
...Analysis department, 11, 13...DP exhaust system, 12...
...RP exhaust system, 14...Low vacuum gauge, 15...High vacuum gauge, 22...Common leak hole, 16, 17, 1
8, 19, 20, 21... valve.

Claims (1)

[Claims] 1 When pre-evacuating the direct sample introduction section, isolate it from the ion source section and analysis section and pre-evacuate it using low vacuum evacuation means; when pre-evacuate the ion source section, isolate it from the analysis section. The low vacuum evacuation means preliminarily evacuates the sample through the direct sample introduction section, and when the analysis section is preliminarily evacuated, the low vacuum evacuation means evacuates the sample through the direct sample introduction section and the ion source section. In addition to preliminary evacuation, when main evacuation of the direct sample introduction section is performed, it is isolated from the low vacuum evacuation means, and the main evacuation means is used to evacuate the ion source section and the analysis section independently, and the ion source section is evacuated. When performing main evacuation, this is isolated from the low vacuum evacuation means and is evacuated by the main evacuation means independently of the direct sample introduction section and the analysis section, and when the analysis section is main evacuation, this is The direct sample introduction section and the ion source section are evacuated independently from the low vacuum evacuation means by the main evacuation means, and when the direct sample introduction section is caused to leak air, the main evacuation means is isolated from the low vacuum evacuation means and the main evacuation means. The ion source is isolated from the exhaust means, the ion source section, and the analysis section to allow air to leak from the common air leak hole, and when the ion source is caused to leak air, it is isolated from the low vacuum evacuation means, the main exhaust means, and the analysis section. When air leaks from the common air leak hole through the direct sample introduction section, and when air leaks from the analysis section, it is shut off from the low vacuum evacuation means and the main evacuation means, and the direct sample is introduced from the common air leak hole. An exhaust and leak method for a mass spectrometer, characterized in that air leaks through an introduction section and the ion source section.