An adjustable LS pressure limiting valve (12) can be built into the A and B ports of pressure-compensated
basic modules to limit the pressure from the individual working functions. Please see the sectional
drawing
PVG 32 sectional view
on page 9 below for better understanding of this example.
The LS pressure limiting valves save energy compared with the shock valves PVLP:
•
with PVLP all the oil flow to the working function will be led across the combined shock and suction
valves to tank if the pressure exceeds the fixed setting.
•
with LS pressure limiting valves an oil flow of about 2 l/min [0.5 US gal/min] will be led across the LS
pressure limiting valve to tank if the pressure exceeds the valve setting.
PVG 32 with closed center PVP
PVG 32 with closed center PVP (variable displacement pump) and PVB with flow control spool.
In the closed center version of PVP an orifice (5) and a plug (7) have been fitted instead of the plug (4).
This means that the pressure adjustment spool (6) will only open to tank when the pressure in channel P
exceeds the set value of the pressure relief valve (1).
In load sensing systems the load pressure is led to the pump control via the LS connection (8).
In the neutral position the pump load sense control sets the displacement so that leakage in the system is
compensated, to maintain the set stand-by pressure.
When a main spool is actuated the pump load sense control will adjust the displacement so that the set
differential pressure (margin) between P and LS is maintained.
The pressure relief valve (1) in PVP should be set at a pressure of approx. 30 bar [435 psi] above maximum
system pressure (set on the pump or external pressure relief valve).
Technical Information
PVG 32 Proportional Valve Group
General description
8 |
©
Danfoss | August 2017
520L0344 | BC00000038en-US0802
