Dynasonics 701_771C Series Insertion Ultrasonic Flow Meter - Manual (Page 6)

Rev. 12/97 -5- D77X
PART 1 - INTRODUCTION
The D77 ultrasonic flow meter is designed to measure the
fluid velocity of liquid within closed conduit. The rugged
insertion probe has no moving parts, is insensitive to
coating buildup and can be accurately positioned at the
precise depth in the pipe required to measure liquid
velocity in a variety of liquid phases. (Conventional,
through the pipe wall, Doppler flow meters are sensitive
to large changes in liquid viscosity and solids content.
The D77 is not sensitive to such changes.)
The flow meter operates by transmitting an ultrasonic
sound from its transmitting piezoelectric crystal into the
flowing liquid. The sound will be reflected by suspended
particles or bubbles within the liquid and recorded by the
receiving piezoelectric crystal. A frequency shift (Doppler
effect) will occur that is directly related to the speed of the
moving particle or bubble. This shift in frequency is
interpreted by the instrument and converted to various
user defined measuring units.
The D77 flow meter can be successfully applied on a wide
range of metering applications. The simple to program
transmitter allows standard D77 to be used on pipe sizes
ranging from 1.5 - 120 inch [ 38 - 3048 mm ] pipe I.D. A
variety of liquid applications can be accommodated: raw
sewage, reclaimed water, cooling water, river water, plant
effluent, mining slurries, sludge, etc. The D77 is ideal for
measuring through thick walled pipes. The D77C is
designed specifically for Crude Oil measurements.
Because the transducers are encapsulated in a resilient
PVDF plastic shell and have no moving parts (in the
traditional sense), the flow meter is very resistant to
fouling and wear. Standard transducers are rated to
180
?
F [82
?
C].
The D77 employs modular construction and provides
electrical safety for the operator. The display face
contains voltages no greater than 15 Vdc and the
enclosure is made from non-conductive fiberglass. All
user connections are made through conduit hole located
on the under side of the D77 enclosure.
General
Application Versatility
User Safety