26
REPAIR INSTRUCTIONS
08
Manual 1843 Rev B p/n 001843 0000
GENERAL
DANGER
!
The pump and parts may
contain hazardous media as
determined by the process.
Assure that pump and parts are
evacuated of hazardous media
prior to servicing.
WARNING
!
Machine should be powered off and secured
with proper lockout / tagout procedures prior
to removal of any guards or panels and to
ensure there are no accidental starts.
CAUTION
!
The electrical service must be isolated and
de-energized prior to maintenance. Apply
appropriate procedures to assure electrical
supply is de-energized and cannot be
inadvertently energized during maintenance.
Assure piping and product are isolated prior
to maintenance of pump. Apply appropriate
procedures to assure piping and product
is isolated and that inadvertent opening of
valves cannot occur during maintenance.
Discharge Valves
If the cause of poor pump vacuum is not due
to leaks or oil contamination, the next step is to
inspect the discharge valves (
see Figure 8-1
).
The discharge valves are located at the exhaust
port of each chamber. They should not cause
trouble unless they are mechanically damaged or
are prevented from sealing properly due to foreign
matter on the valve seat. Under normal pump
usage, the valves should be replaced annually.
When the pump is operating at blank-off without gas
ballast, a sharp valve noise (click) indicates proper
valve operation.
The poppet-type valve has six flat, washer-like
springs which press against a sealing disk. The
disk fits against a seat, forming a tight seal. The
springs are maintained in place by a lift stop and
the entire valve is held together by a capscrew.
The valves are attached to the cylinder by means
of screws and a hold-down plate.
