The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1871-08-03
OPINIONS OF THE PEOPLE.


A Civil Engineer on the Boiler.
To THE EDITOR OF THE HERALD:-
Having assisted professionally in the investi9a-
ton OF many cases of boiler explosions. and al
much difference of opinion appears to prevail as to
the cause OF the terrible calamity on the Westfedb
it may be useful at the present juncture to give q
few OF the results OF considerable practical expe-
rience connected with steam boiler constructions
and explosions. !,
The boiler of the Westheld Is OF an inferior design
and weakly constructed. 1t had already had q
longer life mine years. than is usually allowed til
marine boilers in well conducted companies.
Testing this boiler, intended to work at twenty-3
1ve pounds pressure per square inch, by cold
waite test OF thrtytOur pounds, ID test Of little on
no practical value. Moreover. q thorough inspec-
ton OF a boiler under pressure can only be useful
when every part OF the outside shell is exposed to-
view and the other portions readily accessible. (
An efficient hydrostalc proof pressure of such q
boiler should, according to experience, be double
its ordinary working pressure to give proper ndt
cation OF defects If margin of only nine to ten
pounds on tile working pressure OF twenty-five Wa3
considered to be at or near the bursting pressure Of
thus boiler 1t was obviously IN an unserviceaDle COM
ditOn.
boiler that Will not admit of test of double it,
intended working pressure without permanent ms
Jury TO its structure is OF an improper design and
Tnis viii be readily understood by taking for exi
ample an ordinary cylindrical 1ue boiler, with na1
tIree-eghth inch boiler plate and nues In prOporS
ton. Properly constructed and OF good material
before bursting due to sectional Of the matel
rail will be about three hundred pounds pressure
per square inch. Now, the safe or regular working
PRESSURE for boilers when new should not exceed
one-ffth OF the estimated bursting pressure or say
iesa to- Ths margin Of Strength Is necs
sary provision for safety IN all boilers. y
asSs s n0ng 81 s pes
by corosion ana strain and stress caused by expan
sion and contraction OF the metal In heating andi
The plating Of the westneld boiler Is throughout
much thinner tnan the best boiler making practice
would permit Horizontal seams were single rivet-
ca "a source Or greas weakness, inssoad Of being
In illustration of this point may be mentioned tha
fact that the French government has adopted pref
cise formula with which need not trouble your
readersl, which determines the relative thickness
Of plate and pressure in atmospheres to be used IN
every variety OF diameter or form OF steam genera
I designed and constructed recently several boil
ers and engines Tor use in France Before being
worked the Onlcial Inspector examined them, and
on applying his formula the boiler plating was de-
cared 10 be nearly one sixteenth too night for tho
load on the safety valve, which was ordered 10 be-
reauced from sixty pounds per square inch to fOrtyt
five pounds, before certificate was granted or the
boilers IN question allowed TO be used, although q
proof certificate OF their testing TO 100 pounds pei
square inch was furnished.
The result OF this Preach law is that boiler expo-
slons arc almost unknown in that country, although
1t IL nothing uncommon to see locomotive and Ohef
boilers working ut very high pressures up TO $50
concusively that safety lies not in diminishing the
pressure, but In Increasing the strength OF the
boiler.
100 much stress canno, be put on the great value
OF preliminary examinations and tests OF boilers
before they are put In use.
The explosion OF many boilers Is only question
of time.
Many boilers constructed by me have been tested
10 uOuole their Intended working pressure under
steam ut the request OF the steam users, excel
rent practce, especially in boilers OF untrIed
design, as 1t Will Indicate sources of defect more
certainly IMAM cOlu-Wafer pressure.
Ihere IS no danger provided the boilers are de-
perienced Ia the business.
compulsory government inspection periodically,
% an steam generators by inspectors OF proved
apinty ana proDily, under specific rules defining the
maximum steam pressure permitted In boilers aud
applca0e 10 every variety OF construction, seemS
10 oe the best mode OF preventing In future such
terrible disasters co human life as that OF SUNDAY ,
last. d. A. ROBINSON ~ IA -
Inspection Of the steam Gauge.
To THE EDITOR OF THE HERALD:-