Kobold DVK-12, Operating Instruction

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DVK
page 4 DVK K07/0422
4. Operating Principle
The digital KOBOLD flow meter/monitor model DVK serves to measure and
monitor small and average flows of air in piping and hoses.
The device is absolutely maintenance-free and uses the calorimetric method.
When the operating voltage is applied, a thermistor integrated in the sensor is
heated to a defined value above the medium temperature. When air (or gas)
flows through the sensor, the heat generated in the sensor is absorbed by the
medium. This means that the sensor is cooled down to the medium temperature.
Depending on the velocity and rate of flow, the temperatures are equalized and
the resistance of the sensor is reduced proportionally. The flow velocity can be
determined by measuring the resistance. The medium temperature is measured
by a second sensor.
The resistance values of both sensors are compared by the electronics over a
Wheatstone bridge circuit and an output relay is actuated if the set switching
values have been fallen short or exceeded. The switch state is signalled by two
LED’s (ON: LED on; OUT 1*: green, OUT 2*: red).
The digital KOBOLD flow meter type DVK works with practically no pressure loss.
Typically, the device is available in two different versions (display and sensor as
compact instrument, or display and sensor separated but connected with a cable)
with the necessary screw connections.
* The two outputs OUT 1 and OUT 2 can only be activated by flow measurement per unit of time,
and not by totalising.
5. Instrument Inspection
Instruments are inspected before shipping and sent out in perfect condition.
Should damage to a device be visible, we recommend a thorough inspection of
the delivery packaging. In case of damage, please inform your parcel service /
forwarding agent immediately, since they are responsible for damages during
transit.
Scope of delivery:
The standard delivery includes:

Calorimetric Flow Meter, Monitor, Totalizer Model: DVK-…