CSM 2000 Series
CSM Characteristics
HYDAC FILTER SYSTEMS GMBH
en(us)
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BeWa CSM2000 3211683h en-us 2011-12-01.doc
2011-12-01
CSM Characteristics
The gear pump sucks the oil to be analyzed and conveys it to the Contamination
Sensor, in which the particulate contamination is captured by an optical sensor and
analyzed according to particle size classifications and counted.
Any air bubbles contained in the oil may skew the measurement results as they, like
particulate contamination, cause the measurement cell to generate signals.
The purpose of the CSM is to suppress air bubbles so that the measurement results
are not skewed or only minimally impacted.
Because oil absorbs an increasing quantity of air as the pressure increases (rule of
thumb: ~ 8% air per bar), the ContaminationSensor aims to achieve the greatest
possible pressure. This is done using a downstream pressure relief valve.
However, pressurized air cannot be immediately dissolved in oil, consequently a
path is provided for between the pump and the sensor.
With highly viscous oil and extremely high amounts of air, an air bubble can get
stuck directly behind the pump so that it does not rise and flow out through the
conduit. The pump is unable to pump against this pressurized air. Through the
slightly opened throttle valve located in the conduit between the pump and the
ContaminationSensor, the pressure can reduce and the pump starts to pump oil
again.
In normal operation, only a small portion of the flow is lost at this throttle valve as
the hydraulic resistance of the oil is extremely high. However, air bubbles can easily
escape at this position.
