Edwards ELD500 Series, Инструкция по эксплуатации

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D13510840D - Calibrated leak He 8
Page 69
Calibrated leak He 8
The calibrated leak He 8 has been designed for safe and efficient operation when used
properly in accordance with these Operating Instructions. Observe all safety precautions
described in this section and throughout these Operating Instructions and the Operating
Instructions of the connected leak detector. The calibrated leak He 8 must only be
operated in the proper condition and under the conditions described in the Operating
Instructions. The calibrated leak He 8 must be operated and maintained by trained
personnel only. Consult local, state and national agencies regarding specific requirements
and regulations.
Address any further safety, operation and/or maintenance questions to our nearest office.
We reserve the right to make technical changes without prior notice.
Description
The calibrated leak He 8, which includes its own helium supply, is used for tuning a helium
mass spectrometer and for calibrating the leak rate indication. The calibrated leak He 8
is equipped with a diaphragm valve to shut off the emission of helium gas during zero-
checking of the leak detector. This means that the actual leak is not closed. The helium
supply, which lasts for more than 10 years, flows continuously through the leak and
collects before the valve when it is closed. On opening the valve, the accumulated helium
streams out and causes a temporary deflection on the leak rate meter which is greater
than the nominal leak rate.
The nominal leak rate does not apply if the calibrated leak is fitted to a vacuum
system at pressure of less than 1 mbar. When the calibrated leak He 8 is laid off for
storage, the valve must always remain open to prevent absorption of helium in the sealing
diaphragm. Such absorbed helium would falsify the nominal leak rate and could only be
removed by pumping over a long time. Close the connecting flange using a protective cap
or black flange.
In exceptional cases (particularly when using the calibrated leak on older-type systems) it
might occur that an exact conformity of the calibrated leak rate with the leak detector
reading cannot be achieved. In most of these cases the pumping speed available at the
mass spectrometer will be too low. If this occurs, contact Edwards.
Technical data
Calibrated Leak He 8
Part Number D13550943
Calibration range 10
-8*
mbar ls
-1
*
At a pressure < 1 mbar at the KF flange connection.
Inaccuracy ± 15%
Gas supply Helium
Connecting flange DN 10 ISO-KF
Temperature coefficient +3.5% / °C
Max ambient temperature 70 °C