SF6 Gas Vacuum Chamber Helium Leak Detection System

Test piece

High voltage switch

Maximum test piece size

Provided by customer

Vacuum chamber quantity

One

Vacuum chamber size

Decided by the test piece size

Test piece per chamber

One

Leak rate

Annual leak rate＜0.1%

Convert to Helium Leak Rate 1.23E-6 Pa.m³/sec.

Cycle time

1 hour/piece（from close door to open door）

Tracer gas

Helium

Pressure for helium leak test

0.5 bar

SF6 charging pressure

0.14 MPa（Absolute pressure）

Pressure difference inside and outside the test piece

0.5bar

Does it recycle the helium

Yes

Vacuum chamber and Test piece vacuuming

l  Automatically vacuum the vacuum chamber and test piece at the same time；

l  When the vacuum degree reaches the set value, the evacuation process of the test piece stops, and the vacuum chamber continues to be pumped to the set pressure for leak detection.；

l  During the evacuation of the vacuum chamber, the test piece is checked for large leaks：

Ø  If the test piece has a large leak, the system will stop the inspection program；Large leakage indication signal is given on the operation interface；

Ø  If the test piece has no major leakage, the system continues to perform the following inspection procedures；

During the above detection process, if：

·        The vacuum degree in the vacuum chamber cannot reach the set vacuum value within the set evacuation time；

·        The vacuum degree in the test piece cannot reach the set vacuum value within the set evacuation time；

The system will abort the leak detection procedure and issue an alarm signal；

Background zero suppression,

Fill helium into test piece

and Vacuum helium detection

l  Automatically detect the background signal of helium in the vacuum box and suppress the background signal to zero；

l  Automatic filling of the test piece with helium；

l  Automatically judge the micro-leakage of the test piece：

Ø  If the leak detector finds that there is a helium signal exceeding the set value in the vacuum chamber, it indicates that the test piece has a micro-leakage, and a micro-leakage indication signal is given on the operation interface.；

Ø  If the leak detector does not find that there is a helium signal exceeding the set value in the vacuum chamber, it indicates that the micro-leak detection of the test piece is qualified, and a qualified signal is given on the operation interface.；

Helium Recovery

Ø  Automatic recovery of helium in the test piece until it reach the set recovery vacuum degree；

Vacuum chamber filled with air and Test piece SF6 filling

l  The vacuum chamber is filled with air；

l  During the inflation of the vacuum chamber, the test piece is automatically filled with SF6 of the set pressure；

l  When the SF6 filling procedure is completed and the vacuum chamber is filled with air, the system will give a completion signal；

Test piece unloading

If the test is passes：

l  Vacuum chamber door opens automatically；

l  The operator disengages the in-box joint from the test piece interface；

If the test fails：

l  Manually press the confirmation button, the vacuum chamber door opens automatically；

l  The operator disengages the in-box joint from the test piece interface；

If the device alarms during the detection process：

l  Press the confirm button manually；

Vacuum chamber door opens automatically；Press the touch screen fault information prompt, cancel the alarm state, and then re-detect the test piece.