JPS59119234A - Apparatus for leak test - Google Patents

Abstract

PURPOSE:To make sensibility control easy and to make electrical control possible by controlling the number of revolutions of a turbomolecular pump and controlling the sensibility of an analyzing tube. CONSTITUTION:An auxiliary pump 9 and the turbomolecular pump 8 are driven, it is confirmed that a vacuum gauge 5 indicates <=2X10<-4>Torr, then liquid nitrogen is fed into a cold trap 6 to calibrate the analyzing tube 7. The calibration is performed by opening a standard leak valve S1 and detecting by the analyzing tube gaseous helium sent from a standard leak gas source S2. If the sensibility is low at this time, the revolution number of the pump 8 is decreased by a frequency variable inverter 10. After the calibration, a testing vessel is connected to a connecting hole 1 of a material to be tested, a coarce evacuating valve 2 is opened to evacuate said vessel to <= about 1X10<-2>Torr by a coarse vacuum pump 3, the valve 2 is closed, a test valve 4 is opened and the leak is detected.

Description

[Detailed description of the invention] The present invention relates to improvements in leak test equipment.

In the conventional Yuzu device, a throttle valve that can change the cross-sectional area of the flow path is installed in the middle of the exhaust system to control sensitivity. When sensitivity decreases, the opening degree of the throttle valve is reduced to prevent the decrease in sensitivity. I was preventing it. However, the displacement was not adjusted smoothly using the throttle valve.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a leak test device in which sensitivity can be adjusted by changing the rotational speed of a turbo-molecular pump.

The present invention will be explained below based on an embodiment shown in the drawings.

FIG. 1 shows an embodiment of the first invention.

As shown in the figure, this device includes an analysis tube 7 for sensing leak gas, a cold trap 6 connected to the force inlet side of the analysis tube 7, and a turbo molecular pump 8 connected to a cold trap 06. and a test tube T connected to the cold trap 6, and a variable rotation speed inverter 10 as a rotation speed regulator is electrically connected to the electric motor of the turbo molecular pump 8. . In addition, in Fig. 1, 1 is the connection port of the test object, 2 is the rough pulp, and 8
is a roughing pump, 4 is a test pulp, 5 is a vacuum gauge, 9 is an auxiliary pump, Sl is a standard leak pulp, and S2 is a standard leak gas source.

Next, the operating state in the first invention will be explained.

Drives the auxiliary pump 9 and the turbo molecular pump 8, and the vacuum gauge 5
After confirming that the pressure is below 2 x 10-' Torr, liquid nitrogen is introduced into the cold trap 6 and the analysis tube 7 is calibrated. For calibration, the standard leak pulp 5lt is opened and the rotational speed of the turbo molecular pump 8 is lowered by allowing it to flow out from the standard leak gas source S2. When the calibration is completed, connect the test container to the limb test specimen connection port 1, and insert the rough pulp 2
f Open and rough pump 3 f J I X I Q-2 To
The air is evacuated to below rr, the rough pulp 2 is closed, and the test pulp 4 is opened. Then pass the test. The tracer gas flowing into the test container from the leakage point is led to the analysis tube and is
It is detected as No. 1 and the amount of leakage is determined.

Next, the practical example of the second invention is as shown in FIG.
a vacuum evacuation section having a turbomolecular pump 8 connected to the Illll-bomolecular pump 8; and a test tube T connected to the exhaust side of the Illll-bomolecular pump 8;
The I1 aircraft is electrically connected to a variable rotation speed inverter IO.

In this case, the tracer gas from the connection port 1 diffuses back from the exhaust side to the intake side of the turbomolecular pump 8 and reaches the analysis tube 7. Other parts are the same as the first device.

Next, an example of automatic sensitivity adjustment will be explained based on FIG. 3. When the standard leak valve S is opened, a constant amount of helium gas flows out from the standard leak gas source s2. When the sensitivity calibration switch 25 is pressed, the sensitivity of the leak detector can be automatically adjusted in the process shown below. That is, the first lucky number detected from the analysis tube 7 is detected by the amplifier 2.
The signal is multiplied by 1 and enters the ratio converter 28. A signal set in advance by the sensitivity setter 22 is input to the comparator 23, and by comparison with the signal from the amplifier 21, a rotation speed control signal is output, and the signal is input to the hold circuit 24.

While the sensitivity calibration switch 25 is pressed, this signal enters the frequency strippable inverter 10 as a concave integer regulator and changes the turbomolecular pump 80 rotation speed steplessly. By changing the rotation speed of the turbo molecular pump 80, the pumping speed of the pump changes, and the current output corresponding to 1-1e774 degrees of the analysis tube 7 changes. When the number of the amplifier 21 and the number from the sensitivity setting device 22 are matched, the sensitivity calibration switch 25f is turned on.
When released, the hold circuit 24 continues to output a signal that maintains the current rotational speed.

As described above, in the present invention, the sensitivity of the analysis tube is adjusted by adjusting the rotational speed of the turbomolecular pump, so that the sensitivity can be easily adjusted and electrically controlled. Moreover, no throttle valve is required, making LXP piping easy.)
This contributed to cost reduction.

[Brief explanation of drawings]

Figures 1 and 2 are respectively 1. FIG. 8 is a system diagram showing an embodiment of the second invention, and is a system diagram for automatically performing sensitivity adjustment. 6...Cold trap, 7...Analysis tube, 8...
Turbomolecular pump, 10... variable speed inverter Patent attorney Shinpei Inukai

Claims (2)

[Claims] (1) An analysis tube that detects leak gas, a cold trap with f9:i* on the gas inlet side of the analysis tube, a vacuum exhaust section having a turbo molecular pump connected to the cold trap, and the cold trap. 1. A leak test device comprising: a test pipe system connected to a turbo molecular pump; and a rotation speed regulator electrically connected to an electric motor of a turbo molecular pump. (2) comprising an analysis tube that detects leak gas, a vacuum exhaust section having a turbomolecular pump connected to the gas inlet side of the analysis tube, and a test tube system connected to the exhaust side of the turbomolecular pump; A leak test device characterized in that a rotation speed regulator is electrically connected to the electric motor of the turbo molecular pump.