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Subject: Manufacture of Indented Rotating sphere Sediment Trap

Manufacture of Indented Rotating sphere Sediment Trap

The developers and manufacturer of the Indented Rotating Sphere (IRS)
Sediment Trap (Peterson et al 1993, 2005) are seeking a new manufacturer to
supply the oceanographic community with this technology. 
To date the manufacturer of the IRSC trap has been a small, privately owned
company, Prime Focus Inc, located in Seattle, WA.  Due to the proprietor
reaching retirement, Prime Focus has ceased to produce IRSC traps as of
September 2006.  The proprietor of Prime Focus, Mr. Lee Bond, is willing to
sell complete CAD (AutoCAD Lite) drawings for the trap, pressure cases, and
stainless steel deployment frame as well as all electronic circuit diagrams
for the TattleTale 1V-controller-motor interface.  In addition he has six
Tattletale IVs, and enough raw materials for approximately three traps
which may also be purchased.  Prime Focus was selling theses traps for
around $18,000 complete (trap, pressure cases, electronics and deployment

The IRS valve is patented and will necessitate a licensing agreement with
the University of Washington.

Brief Trap History and Description:
Development of the IRS sediment trap began in the early 1990s and has been
an ongoing collaborative effort among researchers at the University of
Washington (the late Dr. John Hedges and Michael Peterson), State
University of New York at Stony Brook (Dr. Cindy Lee), and Skidaway
Institute of Oceanography (Dr. Stuart Wakeham).  Design and construction of
the prototype was done at the University of Washington which holds a patent
for the application of IRS technology in sediment trap design (U.S. Patent
No. 5,220,825).

The IRS trap (Fig. 1) consists of four cylindrical modules; a particle
interceptor, an IRS valve; a skewed funnel, and an eleven sample carousel
(designated IRSC trap).  The key to the trap design is the patented IRS
valve located between the particle interceptor and particle accumulator
portions of the trap.

Both the valve and carousel are regulated by a TattleTale IVA ( Onset
Computer Corp.) microprocessor.  The controller program allows testing the
trap's performance before deployment, prompts the user for the necessary
input data to control the valve rotation and carousel movement during
deployment, and after the trap is retrieved, downloads performance data
recorded during the deployment.  Batteries and the controller are housed in
separate pressure cases so that batteries may be exchanged without exposing
the electronics to the atmosphere while in the field.

The trap has been deployed on several JGOFS expeditions (EqPAC, ASPS and
AESOPS as well as most recently during the MedFlux program in the
Mediterranean Sea.  Maximum deployment duration is a little more than one
year and the operational depth of the trap extends to 6000 m.  The carousel
sample cups are essentially isolated from the ambient environment by the
IRS valve.  This minimizes washout, erosion of brines in the sample cups ,
and contact between live animals and biocides contained within sample cups.
The modular design in conjunction with the patented IRS valve allows
flexible deployment configurations such as collectors with different
collection cross sectional areas and three different collection modes.

     1.     Times Series scheme:  This is the classical time series
     application which places each sample tube into the collection
     position only once during the trap deployment.

     2.     Daily Repetition scheme:  In the daily collection mode the
     carousel makes one full revolution every 24 hours.  Thus, any given
     sample tube will rotate into the collection position for the same
     part of each day throughout the entire deployment period.  This mode
     allows for sampling schemes like daily composite samples at ~2 hour
     intervals or day/night collections.

     3.     Settling Velocity scheme:  This sampling scheme is designed to
     separate particles not on a temporal basis, but on the basis of their
     settling velocity.  In this mode the carousel is rotated through all
     11 sample chambers each time the valve rotates.  The carousel is
     programmed to move at increasingly longer time intervals between
     samples thereby collecting particles based on travel time between the
     valve and the sample tube (0.68 m distance).

Further information and photos of the trap modules and field deployments
may be found at the following links:
     Peterson, M.L., D.S. Thoreson, J.I Hedges, C. Lee, and S.G. Wakeham.
     1993.  Field evaluation of a valved sediment trap.  Limnol. Oceanog.
     38: 1741-1761.

     Peterson M. L., Wakeham S. G., Lee C., Meaghan A. A, and Miquel, J.
     C.  2005.  Novel Techniques for Collection of Sinking Particles in
     the Ocean and Determining their Settling Rates.  Limnol. and Oceanog.
     Methods, 3, 520-532.

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