Pulsafeeder Pulsa Series 680 EN - Manual (Page 5)

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1.3 Pump Head Assemblies
The hydraulic pump head assembly contains the plunger cylinder and various hydraulic components to
protect and maintain a precise hydraulic balance between the plunger and the diaphragm. Figure No. 3 and
Figure No. 4 shows various styles of pump head assemblies.
1.4 Make-Up, Hydraulic Bypass and Bleeder Valves within the
Hydraulic System
Figures No. 3 and Figure No. 4 show the locations of valves according to piston diameter and diaphragm style
selected.
Make-Up Valve
Any leakage past the plunger or
bleeder, however slight, is replaced
by the make-up valve which
permits flow of replacement oil
from the oil reservoir. This is an
automatic function. The oil loss
allows the diaphragm to get out of
phase with plunger thus creating a
vacuum ahead of the plunger during
the suction stroke. The make-up
valves are factory set.