Improved Blast Apparatus for Locomotives and like Engines.
Year: 1895

page_text: Date of Application, 3rd Oct., 1895
Complete Specification Left, 3rd July, 1896-Accepted, 5th Sept., 1896
PROVISIONAL SPECIFICATION.
Improved Blast Apparatus for Locomotives and like Engines.
We, THOMAS BENJAMIN GRIERSON, of 2 Connaught Street, Kingstown,
Ireland, Engineer, and CHARLES CALVELEY, of 4 Upper Grand Canal Street,
Dublin, Ireland, Engineer, do hereby declare the nature of this invention to be
as follows:-
This invention has reference to the blast apparatus of locomotive and like
engines and according thereto the chimney is constructed with a downward
extension whose lower end is wide mouthed and terminates a short distance above
the blast pipe (which may consequently be shorter than blast pipes are sometimes
made) and the blower pipe is connected to and arranged to deliver into the down-
ward extension of the chimney, into which the vacuum pipe ejector also delivers.
In one arrangement the downward extension of the chimney is of gradually
diminishing cross sectional area for a certain distance and then of gradually
increasing cross sectional area the lower part resembling a hollow truncated cone
above the blast pipe.
Dated this 3rd day of October 1895.
Improved Plast Appar
We, THOMAS BENJAMIN GRIERSON, of 2 Connaught Street, Kingstown,
Ireland, Engineer, and CHARLES CALVELEY, of 4 Upper Grand Canal Street,
Dublin, Ireland, Engineer, do hereby declare the nature of this invention and in
what mauner the same is to be erformed to be particularly described and
ascertained in and by the following statement :-
This invention has reference to the blast apparatus of locomotive and like
a downward
engines. According thereto the chimney is constructed with
extension whose lower end is wide mouthed and terminates a short distance above
the blast pipe which is made shorter than blast pipes are usually made, and the
blower pipe is connected to and arranged to deliver into the downward extension
of the chimney into which the vacuum pipe ejector also delivers.
The accompanying drawing is a cross section through the smoke box of a
downward
locomotive engine the chimney 1 of which is constructed with a
extension 2 according to this invention, through which downward extension all
gases flowing from the smoke box to the chimney are compelled to pass. The said
downward extension is as shown of gradually diminishing cross sectional area for a
certain distance and then of gradually increasing cross sectional area, the lower
part resembling a hollow truncated cone that terminates a short distance above the
blast pipe 3 which is made shorter than usual, with the result that the lower end
of the downward extension of the chimney is at or approximately at (or it may be

page_text: slightly above or below the level of the centre of the cluster of fire tubes 4. By
this arrangement the inducing action caused by exhaust steam passing from the
blast pipe 3 upwards through the downward extension 2 of the chimney causes hot
gases to be drawn into the chimney from the central portion only of the smoke box
whereby the draught through the several rows of fire tubes 4 is more nearly
equalized than has heretofore been usual, with the result that accumulation of
ashes in the lower rows of tubes is prevented and the efficiency of the boiler
increased. Furthermore by the arrangement described the exit end of the blast
pipe 3 can be made larger than usual for an engine of given size whereby the back
pressure will be reduced and the power of the engine considerably increased. 5 is
à blower pipe connected to and arranged to deliver a jet of live steam into the
downward extension 1 of the chimney for producing a draught through the fire
tubes 4 when the engine is standing. 6 is a pipe connected to the downward
extension 1 of the chimney so as to deliver into the same the mixed current
of steam and air from a vacuum pipe ejector, such current aiding the jet of
exhaust steam from the blast pipe 3 in inducing hot gases to flow through the fire
tubes 4.
We are aware that it has heretofore been proposed to provide the chimney of a
locomotive or like engine with a perforated downward extension of gradually
increasing cross sectional area in a downward direction and terminating above the
blast pipe, and also to provide between the bottom of the chimney and the blast
pipe one or more conical tubes, but such arrangements, which we do not claim,
differ from ours in that with them hot gases could be induced to flow into the
chimney from two or more parts of the smoke box, whereas in our arrangement
hot gases can only enter the chimney from the central portion of the smoke box
and in this way a more uniform draught of air can be obtained through the several
rows of fire tubes.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
and
1. Blast pipe apparatus as herein above described for locomotive and like engines
wherein the chimney is constructed with a wide mouthed downward extension
through which all gases flowing to the chimney from the smoke box must pass,
which downward extension terminates a short distance above a blast pipe made
shorter than usual so that the lower end of the downward extension of the chimney
is located at or approximately at or below the level of the centre of the cluster
of fire tubes delivering into the smoke box substantially as described for the
purpose specified.
2. Blast pipe apparatus constructed arranged and operating as referred to
in Claim 1 and in which the blower pipe and vacuum pipe ejector deliver into the
downward extension of the chimney as and for the purpose specified.
3. The construction and arrangement as shewn in and described with reference
to the drawing of blast pipe apparatus of the kind referred to for locomotive and
like engines.