A device comprising a flow channel having an inlet for introducing a flow
of a first material, an outlet for exiting a flow of a second material; a
plunger disposed and slidably movable coaxially within the flow channel;
a first cooling device disposed adjacent to and substantially surrounding
the flow channel comprising a housing having an internal sealable chamber
for containing a first cooling fluid, an inlet having a first seal, and
an outlet having a second seal, wherein the first cooling fluid is
sealable within the sealable chamber; a second cooling device disposed
adjacent to and substantially surrounding the first cooling device
comprising a housing having an internal channel for a flow of a second
cooling fluid, an inlet in fluid communication with the internal channel,
an outlet in fluid communication with the channel, and a device for
controlling the flow of second cooling fluid.