Omnitek S-Flow Automatic Houillon Viscometry System

The kinematic viscosity characterizes flow behavior. This method covers the measurement of kinematic viscosity of transparent and opaque liquids; such as base oils, formulated oils, diesel oil, biodiesel blends, residual fuel oils, marine fuels, and used lubricating oils using an automated Houillon viscometer. 

  • Applicable for fuels, base oils, formulated oils, and petroleum products as well as water-based fluids
  • Compliant with requirements for ASTM D7279, ASTM D2240, and correlation to ASTM D445
  • High throughput: up to 80 samples per hour per bath under ideal operating conditions
  • Very easy to use and maintain
  • Small sample volume: 0.3 - 1.0 mL
  • Low solvent consumption: 2 - 3 mL per sample
  • Extremely accurate temperature control and flow-time measurement independent of fluid type
  • Automatic flow time measurement with ultraprecise meniscus detection
  • Fully automatic cleaning and drying (model dependent)
  • Fast and easy tube replacement (tubes are not connected to optical sensors)
  • No need to drain bath during tube replacement
  • Single or dual solvent injection (model dependent)
  • Integrated Cleaning Pump
  • Integrated VI calculations (on 3500 model only)
  • Stand-alone unit. No PC required. Software operation is available as an option
  • Chemically resistant to allow for all common solvents
  • Optional duplo measurement capability
  • Integrated back flushing
  • Optional software available

The Omnitek S-flow range of instruments consists of compact, bench-top automated viscometry systems for the analysis of used and new lubricants. It is also the ideal system for used oil analysis laboratories that need to test a wide range of lubricant viscosities. Additionally, S-flow systems are used for analysis of fuels like diesel, bunker fuel and bio-fuel (feedstock), hydraulic and metal working fluids and even gelatins and inks. 

The S-flow system is a self-contained viscometer system that consists of a thermostatic bath with circular heater and a control touchscreen. The bath contains 4 viscometer tubes together with optical sensors to detect the flow of oil through the tubes. All measuring tubes function independently of each other. 

The system contains a touchscreen with storage up to 10,000 measurement results. The touchscreen allows the user to control and operate the system. Although a PC is not required to operate the instrument, additional software is available for LIMS connection and full data storage and reporting. The user has the option to operate in two modes, standard viscosity determination or tube calibration. In both modes, the operator chooses how many determinations must be made for an average result. Additional parameters such as tube constants and cleaning cycle are also controlled by the operator. 

Because the sample volume is very low (0.3 - 1 mL), the entire measurement cycle is very short. After the user injects the sample into the tube, the sample travels down towards the optical sensors and heats up to the test temperature very quickly. Upon reaching the first sensor, the time measurement is started. When the second sensor is reached, the measurement is stopped and the result is displayed on the touchscreen or through the PC software. Then, a predefined cleaning cycle automatically commences, cleaning and drying the tubes completely. 

The entire cycle time ranges between 3 - 10 minutes per tube, allowing a throughput of up to 80 tests per hour per bath under ideal operation conditions. After the injection of the sample, operator presence is no longer required. The operator only needs to return after the system has completed the measurement and cleaned the tube. 

S-Flow 970
S-Flow 1250
S-Flow 3500 VI
Number of baths
Viscometers per system
Solvent Injection
Integrated Viscosity Index
Dual Solvent Option
Duplo Measurement Option
Samples per hour*
25 - 40
40 - 80
80 - 160
Optional Robotic Operation


*Samples per hour depends on viscosity, tube, temperature, and solvents chosen

  • Viscometer Tube(s)
  • Starter Kit
  • Backflush Kit
  • Calibration Standards

Conforms to the specifications of: 

ASTM D7279, D2270

    Correlates to ASTM D445

Measuring Range: 0.3 - 3,000 mm2/s (cSt) @ 40 °C

Temperature Range: 20 to 120 °C (68 - 248 °F) (*For temperatures around ambient, and external chiller is required)    

Temperature Stability: Better than ±0.02 °C

Timer Accuracy: 0.001 s

Sample Volume: 0.3 - 1.0 mL

Solvent Consumption: 2 - 3 mL per cycle

Sample throughput: Up to 80 samples per hour per bath (under optimal conditions)

Viscometer Type: Houillon

Sensor Type: Optical

Communication: RS232

PC Control: Multiple instruments can be controlled with one PC

Data Export: USB

115V 60Hz
230V 50Hz


S-Flow 870 / 1250: 17.3 x 18.9 x 24.4 (44x48x62)
S-Flow 2500 VI: 27.6 x 18.9 x 24.4 (70x48x62)

Net Weight
S-Flow 870 / 1250: 70.5 lbs (32 kg)
S-Flow 2500 VI: 136.7 lbs (62 kg)

  • Dual Solvent Cleaning
  • Cooling Coil and Circulator (for measurement around room temperature)
  • Compressor
  • PC for Instrument Control
  • Robotic Operation
  • EasyFlow or Duplo Viscometer Tubes
  • Positive-Displacement pipette
  • Software