Particle Size Analyzers
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LISST laser diffraction particle size analyzers for in-situ use in the aquatic environment (oceans, rivers, lakes, streams, run-off) - and also for cloud droplet research

[Compliant with ISO-13320-1 Standard]

 


Sequoia is the sole manufacturer of the LISST series laser particle size analyzers. The array of instruments originated with applications in the marine environment, but now includes diverse fields such as stream-gaging, paper emulsifier optimzation, airborne cloud dropet measurements and others still in development. Some of these instruments deliver the optical volume scattering function (VSF) of interest to optical oceanographers.

The LISST series includes submersible and non-submersible instruments. All employ the small-angle forward scattering principle, also called low-angle laser scattering or laser diffraction.

Submersible Suspended Sediment Sensors

The submersible series includes:

  • LISST-100X
  • LISST-FLOC
  • LISST-DEEP
  • LISST-ST
  • LISST-25X
  • LISST-SL
Of these, the LISST-100X is our workhorse. It delivers the size distribution of suspended sediments in 32 logarithmically spaced size classes.  Different models of this instrument cover different rnage of sizes.  The LISST-FLOC covers the largest sizes, 7.5 to 1500 microns (nominal), and is intended for measuring flocculated marine particles. These instruments can be used as laboratory instruments, with provided accessories. The LISST-Portable (see below)  is a portable version which can be driven to a site (river, stream, highway runoff..) or carried on an airplane.  LISST-Deep is a deep version capable of operations to 6000m.

The LISST-ST is an extended version of the LISST-100X, with an added Settling Tube (ST stands for Settling Tube). This instrument is designed to perform submerged settling experiments to obtain settling velocities of 8 size classes.  With the settling column removed, the LISST-ST may be used as a -100X, but with less than optimal flow through the sample volume.

The LISST-25X is a patented derivative product. It delivers the suspended sediment concentration and  mean size in two size classes (2.5-63 and 63-500 microns).

All of the above submersible instruments incorporate a depth sensor. They are powered by internal batteries and store data internally.

The LISST-SL is an isokinetic version of the LISST-100X developed for river sediment monitoring. It senses river velocity and adjusts intake velocity to match. Optics and electronics are enclosed. Data are stored on a bridge-top Topside box.

Field and Portable Particle/Sediment Size Analyzers

  • The LISST-Portable
  • LISST-StreamSide
  • LISST-Infinite

The LISST-Portable is a field or laboratory device for particle size and concentration measurements.  It is also battery operated, easily transported (car, airplane), and autonomous. Data are stored on board.

The LISST-StreamSide is meant for use in shallow streams or rivers and is designed for applications where bio-fouling is an issue, or streams are too shallow for instrument submergence, or there exist concerns regarding the safety of the equipment from flowing debris or due to vandalism. The instrument is designed to be enclosed in a shed, wth power provided. A pump is inserted in the stream to deliver water. This device displays the size distribution in real time on a plasma display and stores processed data for subsequent download. Deliveries are planned for mid-2007.

The LISST-Infinite is designed for measuring very high concentrations of sediment, such as occur in rivers or in run-of-river Hydro power plants. The instrument is placed in a shed and again, water is pumped through it. A clean water source is required for dilution. The instrument performas dilutions if needed.

For more information on these instruments, please click on the links at top of this page, or contact us.

A LISST for Emulsifier Optimization in the Paper Industry

The LISST-EO is an in-line process control tool. It is designed to measure particles in the 0.3-60 microns( nominal size). This device employs our standard forward low-angle scattering technology with the reverse Fourier geometry.  The instrument displays the size distribution on a panel-mounted plasma display, and sends the data to a remote desk for display and storage. Deliveries are planned for mid-2007.

A LISST-Wing for measurement of Cloud Droplet Size Distributions
This
instrument was designed for use from research aircraft for studies of cloud droplet processes. It employs the standard forward scatter laser technology of all our instruments. It too records data internally and/or transmits the data over a serial line to the aircraft cabin. The instrument is currently undergoing testing for survival in wind-tunnel environments. For further information, please contact us.






LISST-Portable re-design
Sequoia's LISST-Portable is undergoing a re-design in order to be equipped with a touch panel display similar to the one on the LISST-StreamSide. Also, all dataprocessing will now take place on-board in real-time so no data post-processing is necessary. The first units will ship in October 2008.
California Stormwater Quality Association (CASQA) Stormwater Conference
Oakland, CA, USA
23-24 September 2008

Ocean Optics XIX
Tuscany, Italy, 6-10 October 2008

Particles in Europe - PiE
Bologna, Italy, 13-14 October 2008
   

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