Atec Dynasonics-D902 - Manual (Page 2)

U LTRASONIC FLO W M E TE R
Principles of Opera t i o n
Ultrasonic Doppler flowmeters operate by transmitting and receiving ultrasonic sound signals in liquids. An instrument, such as the
Dynasonics Series 902, incorporates dual transducers that are clamped on opposite sides of a liquid filled pipe. Each transducer
contains a piezoelectric cry s t a l . R e f e rring to the above illustration, the
⌫
1
transducer transmits an ultrasonic signal through the pipe
wall into the liquid. A portion of this signal is reflected by suspended solids, entrained gases or flow turbulence moving with the
fluid, back toward the second transducer,
⌫
2
. E l e c t ronic circ u i t ry compares the transmitted frequency with the received fre q u e n c y.
The diff e rence, or frequency shift, is pro p o rtional to fluid velocity, in accordance with principles developed by Christian Johann Doppler.
If the liquid is not moving (a zero flow condition) the transmitted and received frequencies are identical.
The Series 902 features advanced signal processing and an exclusive auto-adapting digital filter to produce accurate and
stable indications of flow rate and totalized flows. A full function keypad allows field configuration of pipe size, engineering
units, the 4-20mA output and all operating parameters.
Part Number Co n s t r u c t i o n
Transmitter Type
2) U.S. Units
3) Metric Units
Power Supply
A) 115 VAC
B) 230 VAC
C) 100 VAC
D) 200 VAC
E) 12 VDC
Outputs
1) 4-20 mA
Approvals
N) None
Options
N) U.S. power cord
(Two spades and ground)
E) English power cord (Three rectangular spades)
G) German power cord ( T wo round spades)
D90
Relays
N) None
(Std)
Totalizer
A ) Six digit, resettable
TRANSDUCER/TRANSMITTER
(Includes: Accessory pouch, standard transducer, mounting straps, acoustic couplant and power cord.)
D-902 ACCESSORIES
D070-1006-001 High Temp Transducer
D070-1004-003 Small Pipe Transducer
D010-0200-100 Transducer cable extension, 20 feet [6 m]
Fluid Velocity
ϰ ⌫
1
- ⌫
2
⌫
2
⌫
1
⌫
2
⌫
1
RECEIVING
TRANSDUCER
TRANSMITTING
TRANSDUCER
90° ELBOW
Liquids with Suspended Solids or Aeration Clean, Non-aerated Liquids
TOP VIEW OF PIPE