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The HTH Sediment Gravity Corers
History
In the early 90s, professor Ingemar Renberg and Hans Hansson began designing
a unique corer for soft sediment. The idea sprang from the
dissatisfaction of the corers available on the market. There was a lack
of corers with high reliability, supporting samples even under the
toughest conditions with a precise extrusion mechanisms. Hence, the HTH
sediment gravity corer for soft sediment with its unique extrusion
mechanism was designed and built.
The HTH gravity corer for
unconsolidated surface sediments fulfills the need for sediment coring
equipment that is precise, reliable and easy-to-use. It meets the
requirements of the most demanding users, where reliability and
credibility are key features. All parts are made from either stainless
steel or plastics, chosen to avoid sample contamination. Further, the
choice of materials is made to avoid equipment corrosion and to assure
many years of trouble-free use.
Tested under arctic conditions
The corer has been designed for use both in summer- and in winter
conditions, at
sub-freezing temperatures. When used from the ice, the corer will pass
thyrough holes made by a standard 15 centimeter auger.
The principal
The sediment corer allows water to flow freely through the tube during descent
and the closing mechanism is automatic. Penetration into the sediment can be
controlled by adding or removing weights from the corer. The tube is made from
polycarbonate and the length is 500 mm. The corer is available in two sizes,
with a tube diameter (OD/ID) of 70/66 mm or 90/86 mm.
The extruding device gives precision and control when
sectioning the sediment. By rotating the lower part of the extruding
device 360°, the sediment core is pushed upwards in exact 5 mm
increments, 180° gives 2,5 mm thick samples. The lower part of the
extruding device can be readily uncoupled from the treaded rod to allow
fast, free movement
The sectioning tray is attached to the top of the tube
for scraping sediment into sample containers. While plastic containers
are ideal, the tray has a holder to attach plastic sample bags. The tray
is made in one piece from polymethylene plastic (POM) and allows easy
and solid mounting, free from moving parts.
The piston is made from
PE and it is equipped with a
rubber disc instead of O-rings to obtain perfect sealing. The piston is
buoyant.
The transport case
The transport case is designed to accommodate all the parts of the
sediment corer. The base plate of the extruding device can be attached
to the case to allow an ergonomic working position. The case is a NEFAB PlyPak box made of
plywood and UV coated both inside and outside. This type of packaging is
built to last and the galvanised steel profiles create a very strong
design
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