Baseline Systems BHM Series Hydrometer - Manual (Page 30)

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• Hydrometers Operation and Maintenance Manual
Maintenance 3” and 4” Models, Cont.
DIAPHRAGM/STEM ASSEMBLY
AND BASE ASSEMBLY
Diaphragm/Stem Dis-assembly
• Pull the diaphragm and stem assemblies up and out from the
hydrometer cover (11). The central bushing (13) remains attached
to the cover.
• Unscrew and remove the central bushing (13) from the cover (11).
• Inspect the upper and lower central bushing o-rings (12,14).
Replace as necessary.
• Visually inspect the diaphragm (18), valve cover (39) and stem
(40) for damage or excessive wear. If repair or replacement is
required, continue with the following steps.
Diaphragm and Base Dis-assembly
• Remove the six screws (16) from the upper diaphragm ring (17).
Lift the upper diaphragm ring off of the diaphragm (18).
• Lift the diaphragm off of the lower diaphragm support ring (19)
and the stem (40). The stem remains attached to lower diaphragm
support ring.
• Place the stem subassembly upside down on a flat surface.
• Use the extraction tool to remove the valve cover (32) as follows:
- Slide the lower prongs of the extraction tool under the
valve cover.
- Turn the bolt on the extraction tool clockwise until the
extractor seat fits securely into the stem.
- Continue turning the bolt until the valve cover slides
off of the stem.
• Visually inspect the base o-ring (20) and replace as necessary.
• Visually inspect the stem o-ring (41), located in the groove in the
hole in the center of the base. Replace as necessary.
• Inspect the base (21) for cracks or excessive wear. If replacement
is necessary, pull the base off of the stem. Push the replacement
base onto the stem as far as it can go.
WARNING
You must use the extraction tool to remove the valve cover
(39). Use of any other tool may damage the valve cover and
the stem assembly.
Re-assembly
• Insert the diaphragm (18) into the grooves on lower diaphragm support ring (19).
• Place the upper diaphragm ring (17) over the diaphragm. Secure it to the lower diaphragm ring (19)
with the six screws (16). Apply Loctite 270 or similar glue to the screws.
• Push the base up onto the stem as far as it will go.
• Push the valve cover (39) up onto the bottom of the stem. It should easily snap into place.
• Insert the re-assembled diaphragm, stem base assemblies into the cover (11).
• Replace the impeller assembly into the inlet spider, located inside the hydrometer body.
Extraction Tool
Model Number:
00360-000072