Pulsafeeder PulsaPro 900 EN - Manual (Page 36)

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the setting is too low the valve will operate on each discharge stroke. This results in decreased
pumping capacity and will eventually affect the efficiency of the valve.
To check the hydraulic bypass pressure setting, install a gauge and a back pressure valve in the
pump discharge line. The gauge must be between the pump and the back pressure valve (for
convenience, locate the two as close to the pump as possible). With the pump operating at
maximum stroke length, gradually increase the discharge pressure and observe when the HBV
starts to operate through the diagnostic window. The cracking pressure of the valve must be at
least as high as the maximum pressure of the system but no more than 10% over the pump’s
rated pressure. After adjustment tighten the lock nut and reinstall the metal cover.
Periodic inspection of the valve seat is recommended. If it becomes worn or damaged leakage
will occur regardless of how tightly the valve is adjusted.
7.5.1 PTP (Push To Purge) Valve
Figure 18
The PTP (Push to Purge) Valve is a gravity-operated disk check valve that automatically
removes gases from the hydraulic system. On each discharge stroke of the pump, pressure
generated by the piston lifts the disk off a lower seat. If accumulated gasses are present the
gasses flow around the disk and are vented to the reservoir. If there are no gasses present
then oil forces the disk to shut off against an upper seat – limiting the amount of fluid that
escapes. On each suction stroke, the disk returns (by gravity) to the lower seat to prevent
reentry of gas into the system. By this mechanism, under normal operation, a small amount
of oil is displaced with each discharge stroke. This oil is returned by gravity to the reservoir
where it is recycled. The PTP removes minute accumulations of gas long before they are
visible or detrimental to pump operation.
The PTP includes a spring-loaded button at the top of the valve that is used to accelerate the
purging of accumulated gasses in the hydraulics. Holding the button down momentarily
opens the disk valve so that large amounts of gas and hydraulic fluid can be instantly purged.
When the button is released, the valve returns to normal automatic operation. PTP operation
can be monitored by observing oil flow through the small tube behind the diagnostic window.
OBSERVE
PTP FLOW
HERE