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As a policy of continual improvement, STAUFF reserves the right to alter the specification without prior notice.
201.031
Date of Issue: 06 November 2018
6.1.3.2 Manual Flow Control
Another possibility is to fit a simple manual flow control (flow restrictor) to the outlet of the LPM.
This should only be done where the available pressure is less than twice the maximum value
calculated. This is because the small orifice size needed to control the flow from a pressure larger
than this has a risk of blockage.
The flow controller must be fitted to the outlet only. If fitted to the inlet it will have a filtering effect.
The flow controller must be fitted directly to the LPM outlet port.
6.1.3.3 Active Flow Control
This is only needed for operation at high differential pressures, where a too-high flow would otherwise be
generated.
A pressure compensated flow control valve is fitted to the LPM drain outlet. A suitable valve is the LPM-
DAV (see 2.1.2), but other ones can be used
too. This has the effect of a “flow limiter”, maintaining a
constant flow rate even with a varying inlet pressure (provided this pressure stays above a minimum
working value). Below this pressure the valve is wide open so has little effect, i.e. the flow will be less
than the 200
ml/min controlled value. This “minimum working value” will be typically 5-10 bar but will vary
with viscosity. For these lower pressures a flow control valve is not needed and other methods are better
used to control flow as previously described.
Figure 6.12 LPM flow actively regulated
6.2 General Operation
6.2.1 Physical Checks
Oil leaks on and around the unit
Fatigue in hoses and pipework that might then leak when under system pressure
6.2.2 Front Panel Operation
6.2.2.1 Status LED
All LPM versions have a multi-colour indicator on the front panel, which is used to indicate the status or
alarm state. LPM-D versions also have a screen that changes colour. The alarm thresholds can be set
from LASPAC-View via the serial interface.