New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1889-07-01
THE COIL BOILER QUESTION AGAIN.
A REPLY by MR.. CoRYELL 10 SOME REcEN'
CRITICISMS.

REPLY by MR.. CORYELL 10 SOME RECENT
CRITICISMS.
! TO TIE Editor Of The Tribune.
Sir The Importance which the subject of coll
boilers has for tho engineering profession at the
present time IS my for asking space again in
your valuable paper for a statement of their use
and development In France and other European
COUNTRIES It being admitted that they are safe from
disastrous explosions occupy less space and arc Of
much less weight than the ordinary tubulous boilers
which contain largo quantities Of water. As have
stated about 1e 900 horsepower IS in CONSTANT use
on the several vessels OF the French Navy and about
10 600 in the merchant marine. The Russian Navy
has in use and building about IL 600 horse power and
the Spanish Government is using and building con-
siderable amount Of horse power IN Bellevle boilers
In this country there Is total horsepOwer In use Of
| $50 on board yacht and a launch.
That the Bellevlle boiler has passed beyond the
experimental stage can be realized by inspection
Of these boilers on board the French naval and mer
chant steamers and it be definitely settled that
they do come up to expectations and viii result
in large saving of and weight" and in greater
economy, efficiency and durability. The ortogal
be inspected several times in year upon her arrival
from voyage OF twenty-five days continuous steam
ing; the snah from voyage of fortytwo DAYS under
steam. Their boilers will be found. II inspected
TO present conditions so much better than ordinary
ubulous boilers to impress favorably the observer
If he has had experience engineer at on
! long voyages
lie viii realize that coil boilers be thoroughly
cared for by easy and systematic cleaning Of the CRATE
surfaces, heating surfaces and uptakes that their
stcaming efficiency Is never impaired during the
longest voyages because Of the accessibility for all
tho work ssary 70 remove the ashes SCOT that
might clog the heat passages aud impair the draught
and also any deposit from the heating
faces that IS 10 say, regular cleansings at periods
]
and as part Of their regular duties. Through tho
lnterchangeabty of the parts needed repairs be
done at within short space Of time without
stopping slowing down engines This nsures the
unmpaTed efficiency Of the boilers during the longest
voyages. Every requirement IS met in this type of
boilers to commend them to the naval service.
The Milan about four years ago had exhaustive
tests and trials Of her Beevlle boilers made by her
engineer officers. The normal power was obtained by
using fourteen pounds OF fuel per square foot of
on natural draught by forced combustion steam iet
TO hirtytwo pounds, the horse power was doubled on
several trials lasting three and four hours. and with
this larger consumption an average speed was at
tanned Of 1S4l knots. These boilers had very in
terestng test made TO fulfil requirement in the
tract This aliment with salt water only for
a continuous period Of six weeks without injury. Two
boilers OF the group tested one being stopped
al the end Of six and the other after eight weeks OF
working. The result was satisfactory and the order
was given for boilers Of 5000 horse power for
eImorcd cruiser besides other smaller orders.
French engineers have developed the coil boiler TO
practical success which has not attained by the
engineers Of any other country. For the last five
years merchant steamers requiring above 1000 horse
power have been In service having never lost day
from boiler repairs or single minute underway from
casualty.
The boilers quoted By l. J. Az failures arc not
In the comparison being sectional waer-tube boilers
and not coll boilers like the Beeve type. Circu!a
ton In the first being defective. disaster followed, but
In the coil boiler the circulation Is positive and in pro
portion 10 the heat OF the furnace proved by eX
perlments On the Milan. the Actf and other vessels.
and of cord In France. The failures quoted above
occurred many years the French coil boiler was
In use then and has developed TO the success OF the
present time.
In reply 10 illusions 10 the Chicaro's machinery. l
recall the adverse critics In Of the newspapers
extending through several The first trial trip
indicated both design and workmanship In remark,
able manner. The horse power was made easily ana
the speed 10 tract, despite the founeSs OF
the hun under water due causes not pleasant to re
call and which, trust. viii never be repealed
The comparison Of weight per indicated horSe power
Is fair one 10 the Chcagos machinery. with thar
OF tho later vessels her machinery is OF iron theirs OF
steel, and for me same strength pfesumaDB ~ r.
lighter. Taking this into account, her weights
will be found 10 be less than the later yes seis. p
yded the power tests are the same. and we have me
Yorktown ard the Charleston rated upon the &c
velopment of six hours trial, was the Chicago IN
stead Of speed maintained for about three and nan
MINUTES only.
DO not understand me disparaging the new YES,
in workmanship and material they are unsurpassed by
the work Of any foreign builder but evidently i3l-
lowing the purchased drawings has not produced INC
highest possible type vi machinery. Using vertical
cylinders for highsT eed engines IS progressive en-
cheering adopting nc wOrFln beam when low down
machinery IS desired but whenever possible adopting
those designs which reduce the piston friction 10
minimum in all engines for high rotauve Sped am
lessen the inertia OF the moving parts. Then me
takes IFS pafe as the best for the purpose
and puppet valves should he added to attain pesGuon
Scw-YorE June 5. 1880.