B-70315EN/02 3.INSTALLATION
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3.2.1.3 Leakage in external piping
After installing the piping, see Subsection 3.3.2, and be sure to
conduct a clamp test to check for gas leakage.
If the rate of change in primary pressure over eight hours exceeds 5%,
or if the rate of change in secondary pressure over eight hours exceeds
10% for a polyfro (polyethylene) tube or 6% for a stainless pipe,
leakage that prevents normal oscillator operation is present. Use the
helium leakage detector to locate the leakage and eliminate it.
3.2.1.4 Replacing the laser gas cylinder
If the primary pressure of the regulator installed in the laser gas
cylinder is 1 MPa or less, replace the laser gas cylinder with new one.
When laser gas runs out during oscillator operation, the oscillator
stops automatically. In this case, after the oscillator stops, replace the
gas cylinder.
When replacing the gas cylinder, close the main plug of the gas
cylinder, completely loosen the adjustment valve of the regulator, then
remove the regulator. If the adjustment valve of the regulator is left
tightened, external air will enter the piping. When the oscillator is
started after the replacement of the cylinder, the external piping
exhaust operates to remove gas inside the piping, and the oscillator
starts in the normal sequence.
When laser gas runs out during purging, a stop occurs while the inside
of the piping is in the negative pressure state. If the gas cylinder is
replaced in this state, the atmosphere is sucked. Therefore, be sure to
loosen the adjustment valve of the regulator before removing the
regulator.
Before the oscillator starts, the external piping exhaust operation takes
place then the automatic aging function operates to perform aging in
the oscillator to prevent possible troubles from occurring if the
atmosphere should be sucked.