Sequoia Scientific, Inc.

Since 1995, Sequoia Scientific, Inc. has been the global leader in technologies for submersible and field measurements of particles and particle size distributions. The company began with its workhorse product LISST-100X. This was the first instrument which incorporated laser diffraction technology for measuring particles in coasts, ports, harbors, rivers, streams, and reservoirs etc. It remains the only instrument worldwide with this capability.

  • 1(425) 641-0944
  • 1(425) 643-0595
  • info@sequoiasci.com
  • 2700 Richards Road
    Suite 107
    Bellevue, WA 98005
    United States

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Showing recent results 1 - 15 of 18 products found.

  • Acoustic Backscatter Sensor

    LISST-ABS - Sequoia Scientific, Inc.

    The LISST-ABS is a fixed-point monitoring sensor. It uses a new and novel technique to internally compensate for geometric beam spreading and attenuation, yielding de-attenuated backscatter signal strength. It is held pointing into flow for low drag.

  • Constant calibration suspended sediment sensor

    LISST-25X - Sequoia Scientific, Inc.

    Small angle forward-scattering laser diffraction technology (also called laser diffraction)Self-contained with internal batteries and built-in programmable datalogger, holds up to 27,000 samplesSolid state red diode laser @ 670 nmRS232C serial data interfaceProgrammable data collectionIntegrated BioBlock connectionInternal battery (4 x 9V, alkaline or lithium)External power option 6-12VDC @ max 250mA

  • Deep Submersible Particle Size Analyzer

    LISST-Deep - Sequoia Scientific, Inc.

    The LISST-DEEP instrument obtains in-situmeasurements of particle size distribution,optical transmission, and the opticalvolume scattering function (VSF). Using ared 670nm diode laser and a customsilicon detector, small-angle scatteringfrom suspended particles is sensed at 32specific log-spaced angle ranges. Thismeasurement is post-processed to obtainsediment size distribution, volumeconcentration, optical transmission, andVSF. The electronics and opticalconfiguration in the LISST-DEEP are verysimilar to Sequoia’s workhorse, the LISST-100X. However, because of the extremedifficulty associated with keepingalignment under high pressure, the LISSTDEEPhardware design is radically differentfrom the LISST-100X. This allows theLISST-DEEP to be deployed down to 3000m and obtain reliable measurements ofthe in situ particle size distribution andvolume concentration in waters withoptical transmission up to 98.5%.

  • FlowControl-Lab

    Sequoia Scientific, Inc.

    Periodically filtered measurements allow for high-accuracy differential measurements of particle propertiesElectrically-actuated three-way ball valve allows flow to be bypassed through submicron filter cartridge before instrumentationIncludes valve, power supply, controller, one paddlewheel flow sensor, cables, and Windows softwareValve position indicatorFlow sensor data indicates proper system functioning, filter fouling and are used for post-processing and QCRemovable flow sensor windows for flow visualization, cleaning and servicingSoftware allows for valve scheduling, manual setting of valve position and logs flow rates and system state to hourly ASCII filesRugged construction for use in laboratory, ship-board, or dock-side applications

  • FlowControl-Sub

    Sequoia Scientific, Inc.

    Pinch valve design for full-port flow and easy replacement of fouled tubingRapid transition of valve state (~1 s)Auxiliary inputs for analog sensors and Hall Effect volumetric flow sensors (paddlewheel or turbine) [under development]Flexible configuration of valve operation for scheduled or profiling operation, as well as start and stop conditionsContinuous output and internal logging of valve state and depth

  • Particle Size Analyzer

    LISST-STX - Sequoia Scientific, Inc.

    Small Angle Forward Scattering Laser Diffraction Technology @ 670 nmTurbulence suppressing settling columnSubmersible to 200 m depthSelf contained with internal data logger and non-rechargeable battery packProgrammable data collectionParameters Measured:

  • Portable Particle Size Analyzer

    LISST-Portable|XR - Sequoia Scientific, Inc.

    Truly portable – completely self-contained with built-in data logger, processor, rechargeable battery, and 7” color touch screen display.Particle Size Range 0.35 to 500 micronsPumped and recirculating mixing chamber that keeps large and heavy particles suspended.Shock mounted optics block that can withstand the rigors of field use.A built-in ultrasonic probe for complete sample dispersion.Touch panel allows for easy SOP programming, sample analysis and display of data without a PC.Multiple Mie models as well as Fraunhofer model available for inversion, selectable from the touch panelAll data-processing is performed on board and stored in ASCII format. No post-processing necessary.Outputs: Total volume concentration, mean size, standard deviation, optical transmission, D5, D10, D16, D25, D50 (median grain size), D60, D75, D84, D90, D95, D60/D10 (Hazen uniformity coefficient), particle surface area, silt fraction, silt volume, size distribution, battery voltage, sample notes.Based on the laser diffraction principle. Compliant with ISO-13320-1 standard.

  • On-line Sediment Monitoring

    LISST-INFINITE - Sequoia Scientific, Inc.

    otal Concentration between 0.0019 and 0.381 mmConcentration in 32 log-spaced size classes from 0.0019 mm to 0.381 mmConcentration of particles greater than 0.2 mm (and up to 0.381 mm)Concentration of particles between 0.2 mm and 0.075 mmConcentration of particles less than 0.075 mm (and down to 0.0019 mm).

  • On-line Sediment Monitoring

    LISST-Hydro - Sequoia Scientific, Inc.

    Designed for autonomous useOperates from 110/220VAC, 50Hz line powerSelf contained system transmits data to monitoring PC (not included) over RS-485.LISST-Infinite Master Controller and LISST-Infinite Monitor software includedSubmersible well pump for sample intake acquisition (optional)Built in clean water source level monitoringAutomatic background blanking for improved long term performanceWarnings for high sediment concentrations on dedicated monitoring PC (not included)Built-in automatic ultrasonic cleaning

  • Optical VSF Sensors

    Sequoia Scientific, Inc.

    The optical Volume Scattering Function(VSF) is an ‘inherent optical property’ of water that is used by optical oceanographers to predict light propagation, image degradation, remote sensed ocean color, biological environment etc. in water.

  • Radiative Transfer Equation Solver

    EcoLight-S - Sequoia Scientific, Inc.

    EcoLight-S has various options such as solving the RTE at only selected wavelengths and to different depths at different wavelengths (dynamically determined at run time), with unsolved wavelengths and depths being obtained by interpolation or extrapolation. Such options can greatly reduce the run time, but also reduce the accuracy of the computed irradiances and other quantities. EcoLight-S can compute PAR throughout the euphotic zone with less than 10% error in a fraction of a second on a moderately fast computer. When optimized, EcoLight-S is typically 1000 times faster than HydroLight.

  • Radiative Transfer Numerical Model

    HydroLight - Sequoia Scientific, Inc.

    As a data analysis tool: What was the ambient light field when the data were taken?For example, when imaging an underwater object in the daytime, the ambient daylight contributes noise (in this case, path radiance) to the signal of interest (the light propagating from the target to the sensor). HydroLight can compute the ambient daylight field so that it can be subtracted from the total signal received at the sensor to improve the signal-to-noise ratio of the detected signal.

  • Multi-angle Polarized Light Scattering Measurements

    LISST-VSF - Sequoia Scientific, Inc.

    In-situ measurements of P11, P12 and P22 elements of scattering Mueller matrix, (P11 is VSF) from 15-150º.VSF (P11) only at small angles, 0.05 to 10º in 32 logarithmic steps in angles.Only two detectors employed with absolute radiant sensitivity (A/W) calibration.Beam attenuation measured with optics similar to our LISST-100X.Roving Eyeball™ optics permit 1-degree resolution in angles between 15 -150º.Sampling rate at 3 seconds per measurement set (involves 3 turns of Roving Eyeball with unpolarized, vertical, and horizontal polarized laser).Daylight rejection by laser modulation.Dynamic range in VSF measurements extended via laser power modulation.Data from small and large angles in a single data stream, including depth and temperature.

  • StreamLined Isokinetic Sediment Sensor

    LISST-SL - Sequoia Scientific, Inc.

    Small-angle forward laser light scattering (laser diffraction) – compliant with ISO-13320-1 standard.Isokinetic, self-contained operation.2-wire special communication protocol consistent with USGS B-reel use.Real-time display of multi-parameter measurements: Current speed, temperature, concentration, depth, mean sediment grain size.Streamlined shape for low drag (CD <0.2) in fast streams.Twin stabilizer fins facilitate rapid re-orientation into flow on insertion and maintain accurate orientation.4.3” graphics display, 480 x 272 pixels (3.75” W x?2.12” H), 16-bit color allows for easy programming and display of data without a PC.Switch between ft and ft/s or m and m/s for depth and velocity units.Data processing performed on board and stored in ASCII-formatRaw binary data can be post-processed to obtain full size distribution.

  • submersible instrument for measuring

    LISST-STOKES - Sequoia Scientific, Inc.

    Temperature and depth is included for each measurement. Also the beam attenuation at the two wavelengths is included with each measurement. Power is applied externally, either via an external power cable or an external battery pack (included).