The Washington times., 1903-03-22

OF practice. the result OF a quarter
century OF experience. have so improved
insulation that the loss OF heat 10y
radiation by this method is reduced 20
ono-quarte- OF . per cent 70 5 per cent,
depending somewhat upon the amount %
steam used through a given length OF
main.
A "Cold Potential"
The cooling or refrigerating system
pipes will not be cold. as many may be
supposed. but will be at the same tom
pcrature as the gas. water and other
mains. which may be quite high with
out deleterious results. The pipes will
carry a cold potential" that IS,
means OF producing cold or Of taking up
heat The pipe line supplies the means
OF continually taking away heat from
enclosed areas. which is accomplished
by means OF liquid anhydrOus ammonia,
which is sent out through a main pipe
and connected by branch or service
pipes with the customers refrigerator
or other space to be cooled. This liquid
is held under pressure in the pipe. so
It cannot expand or boil or take up any
heat. and thus is at the same tempera-
ture as the ground through which ii
passes. At the refrigerator the LJrid
service pipe is connected 10 a coli Of
piping inside OF tho refrigerator. called
the expansion coil" This coil conr- IS
at it's other end with a second service
pipe and second main laid alongside CT
the liquid line. This is called the "yapor
line" BY the action of the machinery
at the central station low pressure is
maintained in the vapor line and the
expansion coils connected with 1T.
Reverse of Present Methods.
A specially constructed valve allows
the liquid TO trickIe from the liquid line,
where there is pressure. into the expan-
sion coils. where the pressure is about
the same as the atmosphere Tho amount
Of pipe surface and feed of ammonia is
so adjusted that all Of tn" liquid is
boiled to gas in the expansion piping.
and oil OF tie rcfrigerating effect CT tie
liquid IS used up in the refrigerator the
gas which leaves the expansion piping
by way of the vapor line service pipe has
practically no refrigeraing power. hence
the vapor line is also at or very near the
temperature of the ground The refris-
Grating machine at the central station is
continually sucking back the gas and
compresslng it into condensers, where
the heat is squeezed out OF It and taken
away by cooling water. and it is recon
densed to a liquid and again sent out
through the liquid line on its cooling
mission. II will thus be seen that the
cooling methods are exactly the reverse
of steam heating operations.
The Osmium Light.
The advantages attendant upon the
uss of osrnium as the incandescing ma
teriai in electric lamps are not imme-
diately apparent but experiments have
been conducted with this material even
as they have with the Nernst lamp.
The chief difficulties encountered II
the manufacture of the osmium lamp ar'
/ the high cost OF the osmium. its low re
sistance making it suitable only fo'
! low voltage circuits, and it's weakness
making it necessary to support the fla
ment at several points II has been i'm
possible TO make lamps for more thar
forty-1ve volts, but the high efhcienc,
has given the lamp a certain popularity
Where the potentials OF the distribut
| ing circuit are sixty Eve volts or over