ISCO 4230 Bubbler Flow Meter (Discontinued)

  • Large Internal Memory Capable of storing 2 months of flow, parameter, rainfall and sample data taken at 15 minute intervals
  • Hardwearing and Resistant Resistant to the harshest weather environments, ideal for stormwater monitoring. Resistant to debris and corosive flow stream chemicals
Product Options



The 4230 Bubbler Flow Meter uses a bubble line submerged in the flow channel through which an internal air compressor forces a metered amount of air. By measuring the pressure required to force air bubbles out of the line (which is proportional to flow) flow rates can be determined accurately.

The 4230 is resistant to lighting and debris, making it ideal for stormwater monitoring. Wind, steam, foam, turbulence, suspended solids and rapidly changing head heights do not affect the measurement accuracy of the 4230. As the bubble tube is the only equipment in contact with the liquid, harsh chemicals also do not affect operation or accuracy.

The internal software senses rapidly rising heads and maintains accuracy by increasing the bubble rate, and clogging is prevented by automatic bubble line purging. Automatic drift compensation makes the Isco bubbler flow meter range the most accurate level measurement technology. In standby operations (e.g. stormwater runoff monitoring) the Automatic Drift Compensation allows the 4230 to indefinitely maintain calibration.

Standard Features

  • 160 character backlit LCD
  • Built-in flow conversions for most applications including data points, Manning formula, or equations if needed.
  • Accurate on-site printouts using built-in dot matrix printer.
  • Large internal memory can store 2 months of flow, parameter, rainfall and sample data taken at 15 minute intervals.
  • Effects of transducer drift are eliminated with Automatic Drift Compensation allowing indefinitely maintained calibration.
  • Provides interface for sampler activation - connection to multi-parameter water quality sonde and alarm outputs.

Manufactured by: Teledyne ISCO
Model: ISCO 4230 Bubbler Flow Meter (Discontinued)

Services offered for this product

  • Sales
  • Rental
  • Installation
  • Calibration
  • Maintenance


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


4230 Bubbler Flow Meter
Size (H x W x D) 17.0 x 11.5 x 10.5 in. (43 x 29 x 26.7 cm) (without power source)
Weight 17.3 lbs (7.8 kg) (without power source)
Material High-impact molded polystyrene structural foam
Enclosure NEMA 4X (iP65)
Power 12 to 14V DC, 16 mA average at 12.5V DC
Typical Battery Life (printer set at 1 in./hr (2.5 cm/hr), 1 bubble per second, 15 minute purge, and continuous level reading interval)
934 Nickel-Cadmium Battery 7 to 10 days
946 Lead-Acid Battery 10 to 15 days
948 Lead-Acid Battery 2 to 3 months
Program Memory Non-volatile, programmable flash. Updateable without opening enclosure.
Display Backlit LCD, 2-line, 80-character (5.5 mm high x 3.2 mm wide)
Level-to-Flow Rate Conversions
Weirs V-notch, rectangular with and without end contractions, Cipolletti
Flumes Parshall, Palmer-Bowlus, Leopold-Lagco,Trapezoidal, H, HS, HL
Manning Formula Round, U-channel, rectangular, trapezoidal Data Points Four sets of 50 level-flow rate points Equation Two-term polynomial
LCD 9-digit, floating decimal point, resettable
Mechanical (optional) 7-digit, non-resettable
Inputs and Outputs
Rain Gauge Input Contact closure, normally open. Resolution 0.01 or 0.004 in ( 0.25 or 0.1 mm)
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)
Sampler Activation Conditions Enabled, disabled, AND and OR combinations of any two of level, flow rate, rainfall, pH, DO, conductivity, and temperature
Sampler Pacing Output 12V pulse
Sampler Input Event mark, bottle number
Recording Modes Up to 3 graphs of level, flow rate, pH, DO, conductivity, and temperature vs time; includes totalized flow. Rainfall and sampler events (time and bottle number) are also recorded
Speed Off, 0.5, 1, 2, 4 in/hr (1.25, 2.5, 5, 10 cm/hr)
Recording Span User selectable with multiple over-ranges
Resolution 1/240 of recording span
Reports Printed Flow meter program, 2 independent time interval reports, flow meter history, sampler history
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
Printer (continued)
Character Size (HxW) 0.09 x 0.07 in (2.4 x 1.7 mm)
Paper 4.5 in. wide x 65 ft. (11.4 cm x 19.8 m), plain white paper, replaceable roll
Ribbon 19.7 ft. (6.0 m) black nylon, replaceable
Data Storage Memory
Capacity 80,000 bytes (approx. 40,000 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 3,000 sample events. Optional expansion to 473,000 bytes (approx 236,500 readings)
Setup and Data Retrieval Windows-compatible computer with Isco Flowlink Software
Communication Direct connection, optional internal 2400 baud telephone modem with voice messaging, or optional internal short haul modem
Data Retrieval (optional) Isco 581 Rapid Transfer Device (RTD)
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
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
Relay Outputs 2 form C relays with field selectable trip points based on flow rate (with optional High/Low Alarm Relays)
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
Storage Temperature -40° to 140°F (-40° to 60°C)
Operating Temperature 0° to 140°F (-18° to 60°C)
Range 0.1 to 10 ft (0.03 to 3.05 m)
Level Measurement Accuracy (Non-linearity, repeatability, and hysteresis at 25°C (77°F). Max error (±) for indicated level range.
0.1 to 5.0 ft (0.03 to 1.52 m) ±0.005 ft (±0.002 m)
0.1 to 7.0 ft (0.03 to 2.13 m) ±0.01 ft (±0.003 m)
0.1 to 10 ft (0.03 to 3.05 m) ±0.035 ft (±0.011 m)
Temperature Coefficient (Maximum error (±) per degree of temperature change over compensated range)
For level in feet ±0.0003 x level x temperature change from 72°F
For level in meters ±0.0009 x level x temperature change from 22°C
Automatic Drift Correction After a 5 minute warm-up period, zero level is corrected to ±0.002 ft. (±0.0006 m) at intervals between 2 and 15 minutes
Long-Term Level Calibration Change Typically 0.5% of reading per year
Ambient Operating Temperature Range 0° to 140°F (-18° to 60°C)
Compensated Temperature Range 32° to 140°F (0° to 60°C)