The Washington herald. [volume] (Washington, D.C.) 1906-1939, 1921-11-13
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MAKE AMMONIA Gas USE
SAFE ~ WookW09TH BUILprNf
Piptag u wesavorth builoips
rssuarsa rssssreh which resulted r
@Assrsslly lssssafng skyscrsu
building cosss - well ~ discover,.s
. safs use % ammonia Eas. socor6y
ing TO Edward p. Miller, profe,so~(
OF steam engineering at MASSAGE
setts Institute Of Technology, VIZ
In bulistin just issued by the en-.
ginesrfng foundation, actively an.
gaged On fostering research IN thI,
country. asssrts that the necess.ty
Tor research often arises in the or
dinary practice Of engineering
hessarch does not always In
votvs tsdious experimentation
frof MILLER sayl when helpfui
knowisdgs OF former research -
available. and men cooperate, prob-
lems are somstimes quickly ,olyed
The solution Of . problem for ON.
purpose may be useful in many 9TH
err ~ properly recorded. But rec.
ords 60 be useful must be accessible
The technical and scientific ,ocie-
ues sno Journals and our Libraries
can be helpful II utilized: also the
research Information Service Of the
National Research Council"
Ammonia in some forms IA. with
IMMUNITY, used daily for many house
mold purposes but ammonia gas in
quantity 10 deadly" Prof. Miller
continues Nevertheless. this ra,1
10 extensively employed for refrIe-
Grating and other processes. Itms-
be ssfely used. ~ rightly eontrolle1
Some years ago many fatal scc,-
dents occurred due TO safety valve,
on ammonia pipes dischargtnr IN.
gas Into the operating rooms OF re-
frigeratng plants. hotels ana man
ufacturing establishments Az
consequence. Massachusetts ana
New York passed laws requiring
SAFETY valves to have a discharge
pipe through the roof OF the build
ing. the pipe to extend ten feet
above the roof. ~ the adjoining
building were higher.
In New York on. OF IN. ,j,.,
problems encountered under Ga.
new law was the piping in the
man -storieo Woolvor1h Building
on lower Broadway. There were
put lew data available by which
the sine OF the ammonia dischsrg,
pipe could be figured. because 1T
Tie was known about the difference
OF pressure required TO put a given
quantity OF super-heated ammonia
gas through q long pipe. the pipe
being open to the air at one end
Experiments were then made 10 de-
duce formula for the flow Of am
monia gas In a pipe open to the air.
What quantity would flow through
n pipe Of given length and diameter.
under . given pressure at the en-
trance end Of the pipe, Similar ex-
periments were made on the dis 4
charge OF steam. From these data<
II became evident that a two-in
safety valve had to have a six-inc
pipe to discharge. even with fivx
POUNDS pressure above the atmos-
phere at the entrance Of the nine.
the quantity OF ammonia gas that 4
would pass through the two-inch |
safety valve.
The old idea then ca me into the
minds Of two engineers working on
the problem. that the flow Of steam
from 27S pounds absolute pressure
into the air was practically the
same in quantity as the fow Of
steam at 2T5 pounds absolute pres
sure into a chamber where the pres
sure was $50 pounds absolute This
led to the design OF an ammonia
safety valve dischsrging against
back pressure. The question was:
What was the upper limit Of back
pressure that an ammonia valve
could discharge against
'Other series Of tests were made
70 determine this minimum pressure.
II was found that the flow into a
reservoir where the back pressure
was o.5sS times the entrance pres
sure (that is. somewhat more than
half the entrance pressureD was er-
sctly the same as the flow into
reservoir where the pressure was
atmospheric. Az a result. a safety
valve was designed which would
discharge against hs,k pressure
Tests on this valve showed that the
theory was correct. Ammonia safety
valves as built today are capable
OF discharging against this high
back pressure
This. OF course. means that "a
discharge pipe in cases like that
mentioned. instead Of being SKI
inches In diameter. can be % a very
much smaller size. since the en-
trance pressure in this pipe is now
approximately $50 pounds instead
Of five pounds above the atmos-
phere.