IMPROVEMENTS IN BLAST PIPES FOR LOCOMOTIVE AND OTHER STEAM ENGINES
Year: 1874

page_text: LETTERS PATENT to Johannes Detlef Fürst Hald, of the City of
London, Engineer, for the Invention of "IMPROVEMENTS IN BLAST PIPES
FOR LOCOMOTIVE AND OTHER STEAM ENGINES." -A communication from
abroad by L. E. Hoff and O. Adamsen, both of Christiania, Norway.
Sealed the 16th October 1874, and dated the 18th April 1874.
PROVISIONAL SPECIFICATION left by the said Johannes Detlef Fürst
Hald at the Office of the Commissioners of Patents, with his Petition,
on the 18th April 1874.
I, JOHANNES DETLEF FÜRST HALD, of the City of London, Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
BLAST PIPES FOR LOCOMOTIVE AND OTHER STEAM ENGINES," (a communication
to me from abroad by L. E. Hoff and O. Adamsen, both of Christiania,
Norway), to be as follows:-
The object of this Invention is to prevent the back pressure on one:
cylinder piston during the middle part of its stroke, caused by the exhaust
steam from the other cylinder passing into the blast pipe common for both;

page_text: cylinders. For this purpose, according to this Invention, the exhaust
passing into the chimney from each cylinder are kept separate so as not
to interfere with one another, and so that the outer form of the blast
the
pipe and the areas at the exit end are kept large enough to ensure.
best draught compatible with the minimum contraction. The blast pipe
is formed with a partition from the exhaust part of the slide chest up to
the exit. The lower part of the blast pipe is formed as heretofore, and
from the root to the top or exit it gradually tapers off to a flattened form.
The area of each exit opening is as large as the exit opening common for
both in blast pipes as heretofore made or nearly so. If part of the
exhaust passages below the bottom of the blast pipe is formed in one,
then a partition must be formed or arranged there corresponding to the
blast pipe partition.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Johannes Detlef Fürst Hald in the Great Scal
Patent Office on the 16th October 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHANNES
DETLEF FÜRST HALD, of the City of London, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of April, in the year of
our Lord One thousand eight hundred and seventy-four, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Johannes Detlef Fürst Hald, Her
special licence that I, the said Johannes Detlef Fürst Hald, my
executors, administrators, and assigns, or such others as I, the said
Johannes Detlef Fürst Hald, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and
at all times thereafter during the term therein expressed, should and
lawfully might make, use, exercise, and vend, within the United King-
dom of Great Britain and Ireland, the Channel Islands, and Isle of
Man, an Invention for “Improvements in BLAST PIPES FOR LOCOMOTIVE AND
OTHER STEAM ENGINES," (a communication to me from abroad by L. E. Hoff-
and O. Adamsen, both of Christiania, Norway,) upon the condition
(amongst others) that. I, the said Johannes Detlef Fürst Hald, my
executors or administrators, by an instrument in writing under my,

page_text: or their, or one of their hands and seals, should particularly describe.
and ascertain the nature of the said Invention, and in what manner.
the same was to be performed, and cause the same to be filed in the
Great Seal Patent Office within six calendar months next and imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Johannes Detlef Fürst Hald, do
hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained
in and by the following statement, reference being had to the accom-
panying Drawings, and to the letters of reference marked thereon, that
is to say:-
On examining indicator diagrams of coupled high pressure steam-
engines, such as ordinarily used on locomotives for instance, and where.
the exhausts from both cylinders pass off through one common blast.
pipe, it will be found that a back pressure is sustained by one piston.
during the middle part of its stroke, owing to the passage of the exhaust:
steam from the other cylinder into the blast pipe.
The object of this Invention is to prevent or do away with such back.
pressure which causes an appreciable diminution in the efficiency of the
engine, and that the more so the quicker its working specd is. For this
purpose, according to this Invention, the exhausts from each steam cylinder
passing into the chimney are kept separate so as not to interfere with one
another, the outer form of the blast pipe generally remaining substan-
tially as before, and the areas at the exit end being kept large enough to.
ensure the best possible draught compatible with the minimum con-
traction.
And in order that this Invention may be fully understood, I shall now
proceed to describe the same as applied to the blast pipe of an ordinary
locomotive.cngine.
Fig. 1 is a side elevation of cylinder and blast pipe; Fig. 2, vertical
cross section, the dotted lines representing the cylinders for an outside
cylinder locomotive, and the full lines the cylinders for an inside cylinder
locomotive.

page_text: and C¹, and terminates at the exit or outlet at the top of the said blast
pipe A. The lower part of the blast pipe A is formed as heretofore,
but its upper part is somewhat broader because it is double, and each
exit opening is of the same area or nearly so as the common exit of an
ordinary blast pipe, from the root to the top it gradually tapers off to the
flattened form shewn at Fig 3. The partition a may be a sheet-iron
plate cast in.
It is obvious that the two exhausts when thus arranged cannot interfere
with one another, and also that the blast or force of cach exhaust remains
unimpaired.
If part of the exhaust passages below the bottom of the blast pipe is
formed in one, then a partition must be formed or arranged there, corre-
sponding to or in continuation of the blast pipe partition; but if the
exhaust passages or pipes are kept separate for the greater part of their
lengths, then the blast pipe made according to this Invention may in
some cases have to be made in two separate pieces right up to the top.
And having thus fully set forth the nature of this Invention, I
declare that I claim,―
Firstly. Separating the exhaust of coupled high-pressure engines, all
substantially as and for the purpose set forth.
Secondly. Constructing blast pipes for coupled high pressure engines
with a partition, or making it double, all substantially as and for the
purpose set forth.
In witness whereof, I, the said Johannes Detlef Fürst Hald, have
hereunto set my hand and seal, this Thirteenth day of October, in
the year of our Lord One thousand eight hundred and seventy-
four.