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 -30 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.
|Illustration of how the project will bore through the ice to Lake Ellsworth|
“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.”