Pulsafeeder PulsaPro 900 EN - Manual (Page 9)

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2.2.2.1 Push to Purge (PTP)
The Push to Purge (PTP) valve is located at the top of the Pump Head. It
automatically removes air entrained in the hydraulic system. Pressing down on the
button at the top of the PTP overrides its automatic operation. This allows a small
amount of hydraulic fluid to bleed from the pump head to the reservoir every stroke.
Activating the PTP in this manner helps determine if the pump head is properly
primed and diaphragm integrity is maintained.
2.2.2.2 Hydraulic Performance Valve (HPV)
The Hydraulic Performance Valve (HPV) automatically maintains the hydraulic oil
that “connects” the piston to the diaphragm. During normal operation small amounts
of hydraulic fluid is lost past the piston seal and PTP. This causes the diaphragm to
move progressively closer to the button on the HPV valve (see Figure 4, Detail A).
Over time, the diaphragm will come into contact with this button. When this occurs, it
will push the HPV valve open allowing lost hydraulic fluid to be replenished.
2.2.2.3 Hydraulic Makeup Valve (HMV)
The Hydraulic Makeup Valve (HMV) works in conjunction with the HPV to assure
hydraulic oil flows in one direction (into the diaphragm/piston chamber) at the correct
pressure.
2.2.2.4 Hydraulic Bypass Valve (HBV)
The Hydraulic Bypass Valve (HBV) protects the pump from over-pressurizing by
relieving any excess pressure. It is typically set at 110% of the Pump’s discharge
pressure.