Function; Warning - Danfoss PVG 32 Technical Information

Technical Information

Function

Warning

6
PVG 32 AG Modules
When main spools (15) are in neutral position, the pilot operated check valves (hereafter PO Check
valves) are kept closed by a spring plus the work port load, which is directed to the spring side of the PO
Check valves (14) via a small orifice.
If a main spool is actuated to have flow out of the B port, the meter out flow forces the respective PO
Check valves valve to open. At the same time, pilot pressure is guided via the main spool to the back side
of a small pilot valve (12) on the A port side. This will ensure that the load pressure behind the PO Check
valves is released to a separate tank T0 (20) via a seat valve and allow the PO Check valves to open and let
return flow pass across the main spool back to tank.
For float function, both PO Check valves are released to tank at the same time as described above.
In some applications with low load pressure, it is necessary to force open the PO Check valves by a pin
(17). This pin is actuated by means of pump pressure on the A port side.
PVBZ modules cannot be optionally mounted (PVM on A - Port side only).
The separate tank connection T0 is needed to ensure proper performance of the PO Check valvess
regardless of the pressure in main tank line T. It is therefore necessary to connect the T0 port in the Inlet
PVP direct to the oil reservoir with a separate hose, see dimensional drawing examples.
All the valve modules in this technical information have a T0 gallery.
When using PVP with HPCO function (T port can be pressurised) please make sure to lead return flow
from the A and B ports to tank via a separate tank port in the end plate PVST.
W
Warning
All makes and all types of directional control valves – inclusive proportional valves – can fail and cause
serious damage. It is therefore important to analyse all aspects of the application.
Because the proportional valves are used in many different operation conditions and applications, the
manufacturer of the application is responsible for making the final selection of the products- and
assuring that all performance, safety and warning requirements of the application are met.
The process of choosing the control system – and safety level – could e.g. be governed by ISO 13849
(Safety related parts of control system).
11051935 • Rev AE • Feb 2014