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Sequoia Scientific

LISST-STX

Particle Settling Velocity Analyzer

The LISST-STX is a submersible field instrument developed for in-situ observation of the size-dependent settling velocity distribution of suspended particles. It incorporates a mechanized Settling Column.

The LISST-STX is designed to carry out multiple settling experiments while submerged. A motorized mechanism operates the doors that control exchange of water between the settling column and the ambient environment. This permits repeated settling experiments.

A separate built-in motorized stirrer is used to agitate and flush out settled particles after each settling experiment.

For more details about using the LISST-STX as a LISST-100X, read the article ‘Using the LISST-STX as a LISST-100X’.

Click the YouTube video links below to see the motor, door and propellor in action.

Features

The LISST-STX is separated into 2 parts when shipping: the main pressure housing (shown on the left) and the settling tube, shipping in a separate box. It is possible to use the LISST-STX without the settling column attached. In this mode it can be used as a LISST-100X. However, due to the difference in the optics end caps of the LISST-100X and the LISST-STX, no accessories designed for the LISST-100X will work with the LISST-STX, except for cables, clamps, stands, a 50% optical path reduction module and a custom mixing chamber.

The LISST-STX is a fully autonomous, battery operated, self-contained unit. It is engineered for low power consumption and built to withstand the rigors of field deployment. Easy to program features permit flexibility in duration of experiments, and in operating modes.

Featuring:

  • Small Angle Forward Scattering Laser Diffraction Technology @ 670 nm
  • Turbulence suppressing settling column
  • Submersible to 200 m depth
  • Self contained with internal data logger and non-rechargeable battery pack
  • Programmable data collection
  • Parameters Measured:
    • Settling Velocity
    • Particle Size Distribution
    • Particle Volume Concentration
    • Optical Transmission
    • Water Temperature

Specifications

Settling velocities are estiamted for 8 log-spaced size classes covering the range 1.25-250 microns (Type B), or 2.5-500 microns (Type C).

In a Settling Experiment, a water sample is drawn and trapped. The evolution of the size distribution near the base of the settling column during the settling experiment is interpreted to estimate settling velocities.

In addition to particle size distribution histories with each settling experiment, water pressure and temperature are also recorded.

Sediment concentration
  • Range: 1 – 750 mg l -1 (actual range depends on grain size)
  • Resolution: < 1 mg l-1
Sediment size distribution and settling velocities
  • 32 log-spaced size classes for the size distribution
  • 8 log-spaced size classes for the settling velocity distribution
  • Settling velocities from 100 mm/s to 0.01 mm/s
  • 1.25 – 250 µm OR 2.5 – 500 µm size range (to be selected upon ordering)
Mechanical and electrical
  • Dimensions: 32” L x 5” Ø (81.3 cm x 12.7cm)
  • Settling tube: 19.25″ high x 2.13″ square (48.9 cm x cm)
  • Weight in air: 35 lbs (15.9 kg)
  • Weight in water: 18 lbs (8.2 kg)
  • Internal Data Storage:  1,000,000+ size distributions or 14,000+ settling experiments
  • Power: Internal 9V non-rechargeable custom alkaline pack
  • Communications: RS-232 @ 9600 baud
  • Depth rating: 200 m

Accessories

LISST-100X/-STX/ Alkaline Battery Pack
Optical Path Reduction Modules
LISST-100X/LISST-STX External AC Power Supply
Replacement 2-meter Communications Cable
Clamps
Replacement Instrument Stands

FAQ