components in the schematic can be picked out in the photograph, but four
of Robert’s valves are laid horizontally on the bottom LHS and are not quite
so obvious.
The furnace on the right-hand side of Fig. 8.5 shows the heating and
thermocouple wires at the top, and the gas inlet and outlet at the bottom. The
bundle of steel capillaries of the heat exchanger is shown inside the furnace in
the bottom half with the ‘contact substance’ above that—both being part of
the inner tube. Just to the left of the furnace is a plan view of the hexagonal
form of the heat exchanger. In the schematic of the circulation apparatus
however, the furnace is inverted with the thermocouple and heating wires at
the bottom and the gas inlet/outlet at the top. Here, the two components
marked ‘valve’ are not ‘Le Rossignol valves’ but ‘check valves’,
(Rückschlagventil) used to prevent gases flowing in a direction opposite to that
intended. Within the overall schematic for the apparatus is a diagram showing
the additional heat exchanger, essentially a steel tube containing a linear ‘plait’
of three copper tubes interwoven in a spiral and united at the inlet and outlet.
‘Warm’ gas from the furnace passed through this plait into the liquefier,
whilst cold gas from the liquefier passed into the tube containing the plait and
back to the furnace, the whole facilitating an efficient heat exchange.
8.2.4 Using These Machines
The beauty of Robert’s design and engineering can be appreciated by
understanding how these machines were used. Once a possible ‘contact
substance’ had been identified using the simple furnace, it was transferred to
the circulation apparatus. The substance was placed in the modified furnace,
the whole re-assembled, and the bolts tightened. Using the circulation pump
the apparatus was evacuated. The mixture of nitrogen and hydrogen from the
high-pressure reservoir (gasometer) was admitted through the Le Rossignol
valve shown in the schematic just above the pressure gauge. With other Le
Rossignol valves opened, the whole apparatus could be brought to the desired
pressure and once this was achieved the valves were closed. The liquefier was
charged with a mixture of alcohol and solid carbon dioxide kept at −25 to
−39 °C, but mostly around −30 °C. The circulation pump was set working
and a current sent through the heating wires. From now on, circulation was
controlled using Robert’s valves.
Once the apparatus became fully operational the mode of action was as
follows. The gas mixture was sent into the furnace and over the outer surfaces
of the capillary tubes conveying the hot gas away from the ‘contact substance’.
8 The Big Fix …
169
of Robert’s valves are laid horizontally on the bottom LHS and are not quite
so obvious.
The furnace on the right-hand side of Fig. 8.5 shows the heating and
thermocouple wires at the top, and the gas inlet and outlet at the bottom. The
bundle of steel capillaries of the heat exchanger is shown inside the furnace in
the bottom half with the ‘contact substance’ above that—both being part of
the inner tube. Just to the left of the furnace is a plan view of the hexagonal
form of the heat exchanger. In the schematic of the circulation apparatus
however, the furnace is inverted with the thermocouple and heating wires at
the bottom and the gas inlet/outlet at the top. Here, the two components
marked ‘valve’ are not ‘Le Rossignol valves’ but ‘check valves’,
(Rückschlagventil) used to prevent gases flowing in a direction opposite to that
intended. Within the overall schematic for the apparatus is a diagram showing
the additional heat exchanger, essentially a steel tube containing a linear ‘plait’
of three copper tubes interwoven in a spiral and united at the inlet and outlet.
‘Warm’ gas from the furnace passed through this plait into the liquefier,
whilst cold gas from the liquefier passed into the tube containing the plait and
back to the furnace, the whole facilitating an efficient heat exchange.
8.2.4 Using These Machines
The beauty of Robert’s design and engineering can be appreciated by
understanding how these machines were used. Once a possible ‘contact
substance’ had been identified using the simple furnace, it was transferred to
the circulation apparatus. The substance was placed in the modified furnace,
the whole re-assembled, and the bolts tightened. Using the circulation pump
the apparatus was evacuated. The mixture of nitrogen and hydrogen from the
high-pressure reservoir (gasometer) was admitted through the Le Rossignol
valve shown in the schematic just above the pressure gauge. With other Le
Rossignol valves opened, the whole apparatus could be brought to the desired
pressure and once this was achieved the valves were closed. The liquefier was
charged with a mixture of alcohol and solid carbon dioxide kept at −25 to
−39 °C, but mostly around −30 °C. The circulation pump was set working
and a current sent through the heating wires. From now on, circulation was
controlled using Robert’s valves.
Once the apparatus became fully operational the mode of action was as
follows. The gas mixture was sent into the furnace and over the outer surfaces
of the capillary tubes conveying the hot gas away from the ‘contact substance’.
8 The Big Fix …
169