OPEN
CHANNEL FLOW TRANSMITTER
MODEL 872FM - Integral Display
2-WIRE
4-20mA OUTPUT SIGNAL
FIELD PROVEN ULTRASONIC
MEASURING TECHNIQUES
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Datasheet
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Features
- Versatile – Measures
water, sewage, and slurries
- Submergible to 100 feet (30M).
Gastight
- Suitable for most flumes
and weirs. Also custom linearizations to user supplied tables.
- Intrinsically
Safe Classification improves safety and lowers cost of installation
and operation
Application
The Delta
Controls Model 872FM an ultrasonic level sensing
device used to transmit the flow rate of a liquid in an open channel.
The unit
is positioned over the surface of the liquid upstream from a measuring weir
or flume. A series of high frequency sound waves are generated during the "send"
portion of the cycle. The sound waves travel through the air space between
the face of the Sender/Receiver (S/R) unit and the liquid surface. The sound
waves
strike the liquid surface, are reflected, travel back to the S/R unit, and
are detected during the "receive" portion of the cycle. The time
elapsing between "send" and "receive" is measured and
corrected for speed of sound variations due to ambient temperature variations,
and is used
by the instrument to calculate the crest level. The 872FM produces a 4-20 mA
signal that is linearly proportional to flow rate.
Specifications
- Measurement Range:
1 to 8 feet (30 to 250 cm)
- Beam Angle:
± 6° at the 3 dB down boundary
- Output:
4-20 mA analog
- Built-in Temperature
Compensation: Yes
- Accuracy:
Better than ± 0.25% of maximum range
- Supply Voltage:
11-30 VDC
- Ambient Temperature:
-40 to +140°F (-40 to +60°C)
- Housing:
4X Hoseproof and 6 Submergible
- Wiring:
Robust cable with a tough rubber jacket; 10 ft (3 M) basic, longer lengths
optional.
- Calibration:
Integral keypad
- Mounting Connection:
NPT, Flange, or Stem
- Materials:
PVC and 300 S.S.
- Typical Flow
Elements: Parshall and Palmer Bowlus flumes; rectangular, V-notch
and Cipolletti weirs
Optional
- Intrinsically
Safe: CSA (CANADA), NRTL/C (USA), Class 1, Division
1 & 2, Groups ABCD
- Linearizations:
To fit nonstandard elements
- Reduced Head
Room: To 4" (100mm)
- Ranges:
Up to 50 feet (15M)
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