Author: Josiah Wagener
Sunrise: None. It's up all the time
Sunset: 20 February 2014
This summer I spent several days conserving the Fleuss vacuum pump found on the bench in the science corner of the Cape Evans hut. This is a hand powered single cylinder vacuum pump made of cast iron and cast brass.
Fleuss vacuum pump before treatment © AHT/Josiah Wagener
The pump would most likely have been used for drawing a vacuum in a bell jar in order to run chemical experiments at 0 pressure, or to draw chemicals through a filter system for experiments. It was made by the Pulsometer Engineering Co. of Reading, England, from a design patented by Henri Fleuss who was famous for inventing self contained diving apparatus in the late 19th century. He called this model the Geryk after the German scientist who invented the general style of vacuum pump in the 17th century.
Makers plate © AHT/Josiah Wagener
The pump was heavily corroded, having been exposed to over a century of high humidity and regular freeze/thaw cycles. Most of the ironwork had been painted black at one time and part of the vacuum bulb and the pump cylinder had been painted red, however, only flaking traces of the paint remained.
Fleuss vacuum pump after treatment © AHT/Josiah Wagener
Remnants of mercury in the bottom of the bulb and the valve chamber of the pump has resulted in chemical degradation amalgamation leaving some of the metal porous and crumbly. We are unsure of the purpose of the mercury, and would be interested in any knowledge our readers can give us as to its purpose within the pump.
Cracked bulb © AHT/Josiah Wagener
To conserve the item, the rust was reduced with hand tools and abrasive pads then the remaining rust was converted with a tannic acid solution. The resulting dark surface was coated first with acrylic lacquer and then with microcrystalline wax. A brass rod splint was fashioned to hold the cracked bulb in place.
Fleuss vacuum pump on workbench © AHT/Josiah Wagener