Principles Of Operation - WEBTEC HT Series Bedienungsanleitung

Warning: Open the loading valve prior to testing

Principles of Operation

Flow meter
The flow meter comprises an axial turbine mounted in the aluminium base block. The oil flow
rotates the turbine and its speed is proportional to the oil velocity. The revolutions of the turbine
are measured by means of a magnetic sensing head which feeds a pulse every time a turbine
blade goes by to an electronic circuit. The electronic circuit has a built-in micro processor; the
signal is amplified and linearised to maximise accuracy. The readout is an amperemeter which
is calibrated in gpm and lpm.
Pressure gauge
The pressure gauge has a spiral Bourdon tube and a gauge case is filled with glycerine to
ensure good dampening on pulsating pressures. The gauge is connected to the turbine block
by a fine bore capillary tube. The Bi-Directional tester gauge has a shuttle valve which
automatically reads the highest pressure in both directions of flow. A gauge port is provided on
the block for the addition of a low pressure gauge.
Temperature
The Thermistor temperature transducer is in contact with the oil flow and readout is on the
meter scale calibrated 32 - 248°F or 0 - 120°C.
Bi-Directional Loading Valve
The reverse flow valve gives positive shut-off and pressure control in both directions of flow. The
loading valve has two easily replaceable safety discs located in the valve assembly which
internally protect the tester and machine in both flow directions.
Spare Safety Discs
Four spare safety discs are supplied in a threaded storage holder on the rear of the flowmeter
body (see illustration above).
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