Specially designed bellows manufactured by Beakbane for the
National Oceanography Centre (NOC) will play a crucial role in a
pioneering project that will explore Lake Ellsworth, an ancient
lake trapped 3km below the ice of Antarctica.
The project involves drilling down through the ice to the lake
and sending down probes to sample the lake water and the sediments
on the lake bed. The bellows will provide a sealed protective
container for the water sampling probe, ensuring it has no contact
with the outside world and remains sterile from assembly to
deployment in the lake.
Funded by the National Environmental Research Council, the Lake
Ellsworth project consortium is a partnership between British
Antarctic Survey, the National Oceanography Centre (NOC) and eight
UK universities.
The NOC is responsible for designing and manufacturing the probe
that will sample the water in the lake and the system to deploy it
down the 3km borehole in the middle of the polar wilderness.
The 5m long polyurethane bellows manufactured by
Kidderminster-based Beakbane must stay flexible down to -35 degrees
Centigrade, be tough enough to withstand the journey to Antarctica
and withstand exposure to Hydrogen Peroxide vapour.
As Kevin Saw, the mechanical engineer who heads the NOC design
team explains:
"The project will bore through the ice to take samples and
search for life in the waters, which have been cut off from the
outside world for hundreds of thousands, possibly millions, of
years."
The results will show whether life can exist in these extreme
conditions of pitch dark, water temperatures of -2 degrees
Centigrade and high pressures, and give a window on life on earth
in the distant past.
The 5m long probe will contain collection tubes to take samples
of water as it descends through the 160m deep lake while sensors
measure the salinity, temperature, pressure, oxygen level and pH of
the water.
To protect the unique environment of the lake and to ensure that
the experimental results are not compromised there must be
absolutely no possibility of contamination of the lake water by the
probe or the sampling process.
In order to ensure that this is the case, the probe will be
assembled at the NOC under ultra-clean, microbial isolation
conditions and sealed inside the bellows - which will previously
have been sterilised using Hydrogen Peroxide vapour. It will then
be transported to Lake Ellsworth by sea, air and snow tractor.
The bellows and probe will then be attached to the sealed
well-head of the bore hole. As the probe is positioned in the hole
and the winching apparatus is attached, the bellows concertinas
down to a length of just 750mm to sit inside a sealed glove-box
through which the probe will be deployed.
"It seems quite elaborate but it is extremely important. We must
make sure we don't take any microbes down there. So the Beakbane
equipment is absolutely crucial to the success of the expedition,"
says Kevin Saw.
The bellows, which are 5m long, with an external diameter of
300mm and an internal diameter of no less than 205mm are made in
six sections. Each section is cut from clear polyurethane sheet and
thermally formed. The sections and two 500mm end flanges are then
assembled and joined together using high-frequency welding.
Beakbane pays particular attention to the integrity and clean
finish of the welds as it is important that there are no crevices
or dirt traps where bacteria could escape the sterilisation
process.
Kevin Saw says that the NOC selected polyurethane as the best
candidate material for the bellows, as not only did it meet the
temperature and performance requirements, it could also be
clear.
"This was not 100% necessary but if you are doing something that
hasn't been tried before in an extreme environment it's good to be
able to see what's going on.
"When we spoke to Beakbane it was very clear they had the right
experience. They were the only supplier that was geared up for this
kind of thing and were very helpful in developing the
specification. They have done very well and we are very pleased
with the product."
So far Beakbane has supplied two bellows which are now on test
at the NOC.
"They are currently in a refrigerated container which we are
maintaining at -30 degrees, which is a bit colder than we actually
need," says Kevin Saw. "They have been in there for a couple of
weeks now and have remained perfectly flexible. We have compressed
and extended them and they perform exactly as we expected. We have
had no problems with them at all."
Beakbane's managing director Mike Southwell commented: "It is
very exciting to be involved in such a ground-breaking project. Our
great strength is our ability to produce bespoke products that suit
our customer's precise requirements, but this is probably one of
the more exotic challenges we have faced so far."