The news and herald. (Winnsboro, S.C.) 1877-1900, 1881-08-18
Artificial Refrigeration.

-
The production of cold and even ice
by artificial means is now q necessity in
many industrial processes. According
to the continental systems of brewing,
great cold is required not only during
tho actual brewing process, but also for
months afterward while the beers are
maturing in tho cellars. In this coun-
try the natural production of ice is very
uncertain, and some winters may pass
without sufficient being formed to be
worth collection, ana even when leo is
plentiful here we have no suitable ar
rangements at hand for storing and pre-
serving it for use in warmer weather..
For these reasons many ingenious con-
trivances have been devised for the arti-
fetal production Of ice, and it may not
be uninteresting to give some cXplana-
ton Of tho theories on which these ma
chimes are founded. When q volatile
liquid evaporates, q large amount Of
heat is necessarily absorbed by the re-
sulting vapor, and is rendered latent or
imperceptible to the senses and the
thermometer. This heat is taken either
from some Of the remaining liquid or
else from the medium in which the
liquid is in contact. The cold produced
by evaporation is very evident with
volatile fluid like ether; when little of
this liquid is placed in the palm of the
hand an intense feeling of cold is OBJ
served; the ether, in evaporating, must
absorb heat, and therefore takes it from
the nearest body, which is tho hand, and
thus produces corresponding reduction
Of temperature. The evaporation of
volatile liquids is greatly assisted by a
reduction of pressure; and, thus, if
little ether be placed in shallow dish.
floating Oh thin layer of water, and the
whole bo placed under the receiver of an
air-pump. there is not much difficulty
ia freezing the water by rapid exhaust
ion of the air; in this case the vapor o.
ether is renewed almost as fast rs it is
formed, and fresh quantities of liquid
ether are thus volatilized. The various
ice-making and rcfrigerating machines
are constructed so as to utilize this
property possessed by all volatile fluids.
| If the ether be placed in metallic YES
sci exposing a large surface to water or
any other fluid which requires to be
cooled, all the heat necessary for the
volatilization Of the ether must he taken
| from the water the volatilization of the
ether is assisted by means of nn air-
pump, and the ether vapor is then con-
veyed through pipes to another vessel
also surrounded by cold water, where
| it gives up the same amount of heat
again, and is thus converted back into n
liquid In this way a comparatively
small quantity of ether will cool or oven
freeze an indefinite quantity of water,
and the whole Of the ether can be con-
denscd again into the liquid state. In
stead of ether, liquid ammonia, sui
phurous acid, or othcrvery volatile sub
stances may be used, and variety Of
complicated mechanical arrangements
arc introduced to assist in the volatili-
zation, condensation and preservation
of tho volatile agent used. These me-
chanical arrangements have been SO far
perfected that even water itself has been
used MS the evaporating agent, and ice
has been successfully produced by such
means. Great cold and oven ice has also
been produced by the expansion and con-
traction of atmospheric air by machines
constructed on a similar principle to
those We have lust referred to.