The Sigma 950 and 950 AV Series Flow and Water
Quality Meter provide portable and/or permanent single-channel
monitoring plus water quality testing, process control interface, and a
digital display. The Sigma 950 and 950 AV Optiflow models offer maximum
flexibility for multiple applications. Up to three different level
sensor technologies and velocity are available in one meter.
For applications requiring more than flow, the 950
optionally monitors rainfall, pH, temperature, ORP, dissolved oxygen
and/or conductivity. In addition, the 950 has analog inputs for
datalogging from other instruments, for example, total suspended solids
monitors. You can also control samplers, pumps, or other equipment based
on flow or selected parameter(s) exceeding high/low set points with
relay outputs.
Meters in the Sigma 950 Series are versatile to meet
your needs - customize your meter to specific site conditions easily.
The large LCD graphics display lets you quickly see the information you
need quickly, on-site, in your choice of 10 languages, and without the
inconvenience of outdated paper charts; you'll no longer need to replace
pens, paper, or service mechanical recorders.
Industry standard SCADA MODBUS ASCII protocol is
included in the Sigma 950 Flow Meter Series. 4-20 mA outputs are also
available: this allows flexible integration with a SCADA system. You can
have real-time, read-only access to all available data channels in the
950 Flow Meter.
Keypad and large graphics display makes using
laptops in the field optional. A single keystroke provides an
instantaneous flow summary and review of all program settings.
Three level measurement technologies available:
ultrasonic, submerged, or Bubbler.
Battery or AC powered.
Water quality data helps identify upsets that may
affect your plant. An OptiFlow model provides maximum flexibility
with three different level technology choices plus velocity.
Doppler area velocity flow measurement.
Sampler pacing ability to document the extent of
overflow problems.
Optional rainfall logging to record and
characterize rain events.
Remote communications capability via modem or
RS-232.
Enough memory to log more than 18,000 data
points-expandable to 116,000 data points or over one year of flow
data at a 5-minute logging interval.
Flash memory allows software enhancements without
replacing e-proms or returning meter to factory.
Optional four user-assignable alarm relays.
Optional two user-assignable 4-20 mA outputs,
allowing the meter to be part of a current loop able to drive
recorders, samplers, metering pumps, clorinators, and other devices
or SCADA integration.
Rugged, environmentally sealed: the Sigma 950 is
NEMA 4X-6 rated and can survive submersion and corrosive gases-even
with the door open.
Data can be downloaded in any of three ways:
palm-sized Data Transfer Unit (DTU);
built-in modem to transmit data over
telephone lines;
direct RS-232 link to a PC utilizing data
analysis software.
Ideal for:
Long Term or Permanent Flow Studies
Sanitary Sewer Evaluation Studies
CSO Studies and Monitoring
NPDES Stormwater Compliance
Industrial Compliance Monitoring Applications
involving frequent moving of meter to different site conditions
Sigma's Patented Drawdown Correction and the
Bernoulli Principle:
The Bernoulli Principle states that as the velocity of a fluid
increases, its pressure decreases. The Bernoulli Principle simply
describes the relationship between the velocity of a fluid and its
pressure. If a measurement of the pressure of the moving fluid is taken
at a point just forward of the front edge of the shape, and another
measurement is taken at the apex, of the upper curved surface, one would
notice that the pressure at the apex is lower than the pressure at the
leading edge. It is this same principle that is responsible for the lift
on an airplane wing. Level measurement using a submerged depth sensor is
similarly affected by increases in fluid velocity.
As the velocity of water increases past the
probe.
A drop in pressure (vacuum) is induced near the
pressure sensor (level) port located at the sides of the probe.
This results in the lowering of the indicated
level (or pressure) sensed at the port.
Sigma's patented "Drawdown Correction" software
adjusts the level readings for this effect. Sigma's patented
drawdown correction adjusts for these effects through software. The
software correction algorithms are based on flow data collected
during extensive laboratory and real life testing.
This testing resulted in US patent # US5691914:
Fluid flow measurement correcting system, and methods of constructing
and utilizing the same. Abstract: "An apparatus for calculating fluid
flow in a channel, comprising a probe member which detects fluid depth
in the channel; a mechanism for measuring average fluid velocity in the
channel; a mechanism for correcting the detected fluid depth based upon
the measured average fluid velocity in order to account for drawdown;
and a mechanism for calculating average flow rate based upon the average
fluid velocity measurement and the corrected fluid depth value."
*Daniel Bernoulli (1700-1782): Swiss
mathematician, son of Johann Bernoulli, who showed that as the velocity
of a fluid increases, the pressure decreases, a statement known as the
Bernoulli Principle. He won the annual prize of the French Academy ten
times for work on vibrating strings, ocean tides, and the Kinetic Theory
of gases. His Kinetic Theory proposed that the properties of a gas could
be explained by the motions of its particles. He was the first person to
encounter the functions today known as Bessel Functions.
Address:
Hach/Marsh-McBirney, 4539
Metropolitan Ct.
Frederick, Maryland
21704 USA
Telephone: U.S. and Canada 1-800-368-2723
Outside the U.S. 1-301-874-5599 - Fax: 1-301-874-8459
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Hach/Marsh-McBirney All rights reserved.
