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8.7 Hydraulic Performance Valve (HPV)
PulsaPro pumps utilize the high-performance valve which is integrated within the dish plate to
preserve hydraulic balance. The valve is factory preset and requires no maintenance provided the
hydraulic oil remains clean. When the valve is actuated, oil can flow into the hydraulic system until
the piston reaches the end of the suction stroke.
As the piston starts forward a check valve prevents oil from flowing back through the HPV, thereby
allowing the valve to close as the diaphragm moves forward. Through this process the diaphragm
is continually maintained in a proper operating position relative to the pump head dish plate. Since
the HPV is unaffected by the vacuum level in the
pump head, oil cannot be inadvertently brought into
the hydraulic system which would result in over
extension and damage to the diaphragm. This
feature provides the pump protection should the
suction line become restricted or closed.
The check valve (HPVC) in series with the HPV
includes a screen to trap contaminants and should
be removed and cleaned with each change of
hydraulic oil as indicated. A clogged filter screen will
impede the operation of the HPV and can lead to
diaphragm damage. If a diaphragm has failed, and
chemical has contaminated the pump head
assembly, both HPV and HPVC should be removed
and thoroughly cleaned.
Figure 38
Check Valve Screen (HPVC) – Removal and Cleaning
o
Disconnect power, relieve all pressure, and drain the hydraulic fluid.
o
Unscrew the check valve from the bottom of the pump.
o
Clean the valve and screen in a solvent compatible with the nitrile seal material and blow
air through the valve to remove all contaminants.
o
Inspect the copper gasket and O-ring for nicks or other damage and replace if necessary.
o
Lubricate the O-ring with PULSAlube 6H and install the valve, tightening securely.
o
Re-install the drain plug and refill the hydraulic oil.
Figure 39
