An Improved Spark Arrester.
Year: 1891

page_text: Date of Application, 23rd Nov., 1891-Accepted, 24th Dec., 1891
An Improved Spark Arrester.
I JOHN THORNTON of Oxford Chambers Bourke Street, Melbourne in the
Colony of Victoria, Contractor, do hereby declare the nature of this invention and
in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement:-
To arrest sparks and prevent them leaving the smoke box of a locomotive or a
portable engine boiler, arrange a cylindrical or a conical cage made preferably
of ring or link wire netting to enclose or surround the space between bottom of
funnel and top of exhaust pipe, the meshes between the links or rings of the netting
being as fine as it is possible to have them without retarding the draft, consequently
no sparks or cinders of a size large enough to do damage can pass out of funnel,
any small ones that may pass through the netting being extinguished by the
exhaust steam. The top edge or ring of the cage I support from a flange or bolt
or secure it under the crown plate of smoke box while the bottom ring or edge
of cage I secure to a flange upon exhaust or blast pipe. The side of netting I
leave somewhat slack so that at each puff or exhaust of the steam the netting of
cage is vibrated or in other words the netting is kept in a state of tremor whilst the
engine is working and thus no sparks or cinders can remain in the meshes or links
of the netting. When so desired I may use two layers of netting for the cage.
In order that my invention may be fully understood I attach a sheet of drawings
which illustrate the several forms that the cage may take when employed in the
smoke box of a locomotive or a portable engine boiler.
In Fig. 1 the cage A. is of cylindrical form its top edge or ring being secured
to the flange B under crown plate of smoke box and around bottom of funnel C
by hook bolts B. The bottom edge or ring of cage passes some distance below
top of exhaust pipe D and is then secured or bolted to a flange D'. When the
cage is of a much larger diameter than the exhaust pipe its bottom flange end may
be perforated. In Fig. 2 the cage A is shewn of a conical form with its lower
ring or end secured to flange D' around blast pipe D. In Fig. 3 the cage A is
again shewn enclosing the space between top of exhaust pipe D and bottom of
funnel C but the cage is neither cylindrical nor conical as its sides stretch to and
terminate upon face of tube plate. In Fig. 4 the cage A is conical and suspended
around bottom end of funnel C and above exhaust pipe D while in Fig. 5 I show
pattern of the ring netting that I prefer for the cages.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what 1
claim is :-
1. A spark arrester consisting of a cylindrical or a conical shaped cage formed
of link, ring or woven wire netting that surrounds the space between opening
leading to funnel and top of exhaust pipe as herein described and as illustrated in
Figs. 1, and 2 of my drawings.
2. The use within the smoke box of locomotive or portable engine boilers of
link, ring or woven wire netting as a spark arrester, arranged preferably in the
form of a cage as herein described and as illustrated in ny drawings.
Dated this 22»d day of Novembar 1801
JOHN THORNTON.
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents