Thermo Scientific 48i Instruction Manual page 150

Preventive Maintenance
Pump Rebuilding
5-6 Model 48i Instruction Manual
4. Remove the four top plate screws and remove the top plate. Note the
positioning of the flapper valve relative to the valve ports on the top
plate and bottom plate. Lift off the flapper valve.
5. Remove the bottom plate.
6. Check that all parts are clean from dirt and clean as necessary. DO
NOT scratch the parts.
7. Removal of the old diaphragm: Rotate the fan so that the diaphragm
is positioned at the top dead center. This will help unseat the edge of
the diaphragm. If required, push up from underneath the diaphragm or
use a non-metallic tool to pry up the diaphragm from the housing
groove. Unscrew the old diaphragm by turning it counterclockwise
using both hands. DO NOT use tools!
Note Take care not to lose the shim rings positioned between the
diaphragm support cup and connecting rod, as the same shim rings must
be used during re-assembly.
While unscrewing the diaphragm with one hand, use your other hand
to secure the support cup and shim ring(s) onto the diaphragm stud.
Lift the diaphragm, support cup and shim ring(s) from the pump.
The compressor housing cover must be removed to gain access to and
secure the support cup and shim ring(s) onto the stud. Note that the
quantity and thickness of the shim ring(s) will vary from pump to
pump. Parts removed must be replaced exactly as found. If repairing
multiple pumps, take care not to mix the parts.
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Thermo Fisher Scientific