MKS HPS 917, Руководство по эксплуатации и обслуживанию

Страница: 24 / 32

18 Pirani Vacuum Sensor System
Using the Series 917 Pirani
System
with Other Gases
Before using the Series 917 Pirani System to measure
pressure of gases other than air or nitrogen, you should read
andunderstand this section. To answer further questions,
contact the Customer Service Department of
HPS
TM at 303-449-9861.
The Series 917 Pirani System is designed to give voltage output for air/
nitrogen, argon, or helium according to the graph on page 14 or the table on
page 15. If the Pirani System is used to read pressure of gases with poorer
heat transfer properties than nitrogen, the true system pressure may be much
higher than indicated.
This reading error could lead to a dangerous
overpressure.
A system which is backfilled from a pressurized gas source
should contain a safety device, such as a burst disc.
Calibrating for Other Gases
To determine the voltage/pressure relationship for gases which are not shown
in the graph or table, you need to calibrate the Series 917 Pirani System with
this gas. This calibration requires a gas-type independent sensor, such as a
capacitance manometer, to act as a standard. A curve like that of page 14
can then be generated.
Calibrating for Direct Measurement
The Series 917 Pirani Controller is not intended to be calibrated for direct
pressure readings of gases other than air or nitrogen. The calibration is
intended
only to match the air/nitrogen curve of the Controller to the
characteristic of a particular sensor.