WEBTEC DHC 51 Operating Manual page 4

Operation
MODELS: DHT and DHC
Temperature
The thermistor type temperature transducer is in contact with the oil flow and temperature is
displayed on the left hand side of the digital display. The factory preset units are indicated by a
cursor arrow.
Flow
A) Flow Meter
The Flow Meter comprises an axial turbine mounted in an aluminium 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 electric circuit. The circuit amplifies the pulse, shapes it into square wave
form and has a digital output which is directly proportional to the number of pulses per second.
Flowrate is displayed in the right hand side of the digital display. The preset units are displayed
in either USGPM, IGPM or LPM and the selection is indicated by a cursor arrow. When the flow
rate falls below the minimum allowable "L" is indicated on the display. When flowrate exceeds
the maximum "H" is indicated on the display.
Pressure Gauge
The pressure gauge has a spiral Bourdon tube and the gauge case is filled with glycerine to
ensure good dampening on pulsating pressures. The gauge is connected to the turbine block
by fine bore capillary tube. Testers with BUILT-IN load valve have a shuttle valve which
automatically reads the highest pressure in both directions of flow.
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.
Accessories
Adaptors. Fitting kits are available for all testers. Consult Sales Office.
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