CETN-II-12
3/86
positions corresponding to the number of tubes in the cassette. After a
sample is taken with the ram, the indexing table is fired, rotating the
cassette clockwise to align the next sample tube under the ram. The indexing
table is rated for maximum working pressure of 80 psi and a maximum allowable
load of 454 kilograms. Like the ram, it is powered with a scuba bottle.
Cassette
3.
The cassette is used as `a guide for the sample tubes and as protection for
the samples against wave energy. The cassette is composed of 18 aluminum
pipes 10cm (4-in. diameter) and two 0.6 cm (l/4-in.) aluminum plates; one
welded at the top of the pipes and one at the bottom (Fig. 2). It is bolted
onto the indexing table and guides the sample tubes in and out of position
under the ram. The prototype cassette holds a maximum of 18 sample tubes. A
plate of 1.2 cm (1/2-in.) nylon bolted to the base of the sampler provides a
smooth surface on which the cassette turns.
Sample Tubes
4.
The sample tubes are industry standard 7.6 cm (3-in.) stainless steel
Shelby tubes. Figure 4 is a cross-section through a sample tube illustrating
the components in their respective positions. Modifications to the tubes
include a 0.3 cm (1/8-in.) steel ring welded to the inside at the bottom of
the tubes to act as a stop for the core catcher. The core catcher is made of
nylon and is used to prevent sample loss during and after sample recovery. A
plastic liner placed inside the steel tubes from the top abuts the core
catcher . . The plastic liners are withdrawn after a sampling run is completed
and cut lengthwise to expose the sample. An aluminum ball valve is placed in
the tubes and seated against the liner. The valve is used to create a vacuum
in the sample tube during extrusion to increase sample recovery. Finally, a
steel coupling is placed on top of the sample tube acting as the connection
between the ram and the tubes. Future modifications will combine the ball
valve and steel coupling to simplify sample tube preparation.
Control Elox
5.
The control valves used for operation of the ROSCO are housed in a
46 Cm (18-in.) by 35 cm (14-in.) metal box. The box contains two single stage
regulators with gauges for reading the pressure (one each for the ram and
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