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4230 Bubbler Level Sensing Flow Meter with 1/16" × 25 foot Teflon bubble line

Part Number: 68-4230-001Product Details


Bubbler level sensing provides the most accurate measurement.
Isco 4230 Bubbler Flow Meters use an internal air compressor to force a metered amount of air through a bubble line submerged in the flow channel. By measuring the pressure needed to force air bubbles out of the line, the flow level is accurately determined.

Measurement accuracy of the 4230 is not affected by wind, steam, foam or turbulence, nor by suspended solids and rapidly changing head heights that can cause problems for some bubbler flow meters. Because only the bubble tube contacts the flow, corrosive chemicals are not a problem. The 4230 also resists damage by lightning and debris, making it ideal for stormwater applications.

Automatic Drift Compensation makes Isco bubbler flow meters the most accurate level measurement technology. In standby applications such as stormwater runoff monitoring, Automatic Drift Compensation also allows the 4230 to maintain calibration indefinitely. Automatic bubble line purging prevents clogging, and the meter's internal software senses rapidly rising heads and increases the bubble rate to maintain maximum accuracy.

• Built-in flow conversions for most applications, including Manning formula, data points, or equation for special situations
• Two-line × 80-character backlit LCD
• Choice of standard (10 ft) and extended (30 ft) level measurement range
• Built-in dot matrix printer gives you an accurate, on-site printout
• Internal memory stores over 2 months of flow, rainfall, parameter, and sample data at 15 minute intervals
• Automatic Drift Compensation eliminates effects of transducer drift and allows the 4230 to maintain level calibration indefinitely
• Interfacing for Sampler activation, connection to multiparameter water quality sonde, alarm outputs


• Portable and fixed-site flow measurement with weirs and flumes
• Pretreatment Compliance
• Stormwater Runoff Monitoring
• Permit Enforcement
• Sewer Flow Monitoring
• Combined Sewer Overflow Studies
• Wastewater Treatment Plant Operations
• Inflow and Infiltration Studies
• River and Stream Gauging


Part Number: 68-4230-001
0.03m to 1.52m (0.1 ft to 5.0 ft) ±0.002m (±0.005 ft)
0.03m to 2.13m (0.1 ft to 7.0 ft) ±0.003m (±0.01 ft)
0.03m to 3.05m (0.1 ft to 10 ft) ±0.011m (±0.035 ft)
934 Nickel-Cadmium Battery 7 to 10 days
946 Lead-Acid Battery 10 to 15 days
948 Lead-Acid Battery 2 to 3 months
Ambient Operating Temperature Range -18°C to 60°C (0°F to 140°F)
Analog Outputs (optional) Up to 3 isolated internal outputs, 0 to 20 mA or 4 to 20 mA, scaleable based on level, flow rate, pH, DO, conductivity, or temperature, into a maximum of 750 ohms each
Automatic Drift Correction After a 5 minute warm-up period, zero level is corrected to ±0.0006m (±0.002 foot) at intervals between 2 and 15 minutes
Capacity 80000 bytes (approximately 40000 readings) divided into a maximum of 12 memory partitions. Equal to 100 days of level, rainfall, pH, DO, conductivity, and temperature readings at 15 minute intervals, plus 3000 sample events. Optional expansion to 473000 bytes (approximately 236500 readings)
Character Size (H × W) 2.4mm × 1.7mm (0.09" × 0.07")
Communication Direct connection, optional internal 2400 baud telephone modem with voice messaging, or optional internal short haul modem
Compensated Temperature Range 0°C to 60°C (32°F to 140°F)
Data Retrieval (optional) Isco 581 Rapid Transfer Device (RTD)
Display Backlit LCD, 2-line, 80-character (5.5mm high × 3.2mm wide)
Enclosure NEMA 4X (iP65)
Flumes Parshall, Palmer-Bowlus, Leopold-Lagco,Trapezoidal, H, HS, HL
For Level in Feet ±0.0003 × level × temperature change from 72°F
For Level in Meters ±0.0009 × level × temperature change from 22°C
Interval Report Contents Site number; time interval; total flow; minimum, maximum, and average flow rate, level, pH, DO, conductivity, and temperature, and time of occurrence; interval flow; total rainfall; number of samples, flow meter history and sampler history
LCD 9-digit, floating decimal point, resettable
Long-Term Level Calibration Change Typically 0.5% of reading per year
Manning Formula Round, U-channel, rectangular, trapezoidal Data Points Four sets of 50 level-flow rate points Equation Two-term polynomial
Material High-impact molded polystyrene structural foam
Mechanical (optional) 7-digit, non-resettable
Operating Temperature -18°C to 60°C (0°F to 140°F)
Paper 11.4cm wide × 19.8m (4.5" × 65 foot), plain white paper, replaceable roll
Parameter Inputs pH, dissolved oxygen, conductivity, and temperature (with optional YSI 600 sonde); pH and temperature (with optional Isco 201 Parameter Module); or dissolved oxygen and temperature (with optional Isco 270 Parameter Module)
Power 12 to 14V DC, 16 mA average at 12.5V DC
Program Memory Non-volatile, programmable flash. Updateable without opening enclosure.
Rain Gauge Input Contact closure, normally open. Resolution 0.25 or 0.1mm (0.01 or 0.004 inch)
Range 0.03m to 3.05m (0.1 foot to 10 foot)
Recording Modes Up to 3 graphs of level, flow rate, pH, DO, conductivity, and temperature vs time; includes totalised flow. Rainfall and sampler events (time and bottle number) are also recorded
Recording Span User selectable with multiple over-ranges
Relay Outputs 2 form C relays with field selectable trip points based on flow rate (with optional High/Low Alarm Relays)
Reports Printed Flow meter program, 2 independent time interval reports, flow meter history, sampler history
Resolution 1/240 of recording span
Ribbon 6.0m (19.7 foot) black nylon, replaceable
Sampler Activation Conditions Enabled, disabled, AND and OR combinations of any two of level, flow rate, rainfall, pH, DO, conductivity, and temperature
Sampler Input Event mark, bottle number
Sampler Pacing Output 12V pulse
Serial Output Current status and readings, in response to command or automatically at selectable time intervals, ASCII comma separated values at 1200, 2400, 4800, or 9600 baud
Setup and Data Retrieval Windows-compatible computer with Isco Flowlink Software
Size (H × W × D, without power source) 43cm × 29cm × 26.7cm (17.0" × 11.5" × 10.5")
Speed Off, 1.25, 2.5, 5, 10 cm/hr (0.5, 1, 2, 4 in/hr)
Storage Temperature -40°C to 60°C (-40°F to 140°F)
Voice Messaging (with optional internal modem) Calls up to 5 telephone numbers with programmable delay between calls, activated based on AND and OR combinations telephone of any two of level, flow rate, rainfall, pH, DO, conductivity, and temperature
Weight (without power source) 7.8kg (17.3 lbs)
Weirs V-notch, rectangular with and without end contractions, Cipolletti

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