PVBS main spool for pressure control
PVBS - main slide for pressure control.
In some systems, the load-controlled pump pressure can result in an unstable regulation of the oil flow and a tendency to self-oscillate. It can, for example, apply to work functions with a large moment of inertia or load holding valves. In such systems, PVBS main sliders for pressure control can be advantageously used.
The sliders are designed so that the pump pressure is controlled by the slider's equipment. The main slider must be equipped so far that the pump pressure just exceeds the load pressure before the work function is moved. If the main slide is held, the pump pressure is kept constant - even when the load pressure changes. This provides a stable system.
However, the use of pressure control sliders also means that:
- the oil flow is load-dependent,
- the deadband is load-dependent,
- the pump pressure can exceed the load pressure more than normal.
Pressure control sliders should therefore only be used when you know with certainty that you will have - or already have - stability problems.
