Table of Contents
Advertisement
Replacing the Pirani element
6.2.3 Reassembling FRG-700
Inverted Magnetron Pirani Gauge FRG-700 FRG-702
( figure 20)
Remove the FPM seal (13a) from the Pirani element (13).
Fill the Pirani measuring tube with cleaning alcohol and let it work.
Pour the alcohol out of the tube.
Dry the tube (e.g. with a blow dryer <150 C).
Slide a new FPM seal over the Pirani element and insert it into the corre-
sponding groove.
Reinstall the Pirani element ( 22).
If it is severely contaminated or defective.
Slide a new FPM seal (13a) over the Pirani element (13) and insert it into
the corresponding groove.
Mount the Pirani element ( 22).
Insert the FPM seal (11) with the support ring (12) centered into the
measuring chamber (7). The sealing surface, seal, and ceramic part must
be clean.
Carefully insert the anode (10) incl. ignition aid (10a) into the measuring
chamber.
Insert the Pirani element (13) with the FPM seal (13a) slid over it into the
corresponding bore hole.
Carefully place the pressure piece (9) on the measuring chamber and
tighten them with the three hexagon socket screws (8) incl. lock washers
(8a) uniformly until the stop position is reached.
Position the ignition aid (10a) by pushing the mounting tool over the anode
pin until the mechanical stop is reached.
Blow the particles in the measuring chamber with dry nitrogen (be careful to
hold the measuring chamber with the flange pointing downwards).
Slide the polarity insert (6) into the measuring chamber until the mechanical
stop is reached.
Place the circlip (5) snugly fitting on the polarity insert.
Visually check that the anode pin is centered over the middle
hole of the polarity insert (max. eccentricity = 0.5 mm).
22
Advertisement
Table of Contents
