Improvements in Blast Pipes or Apparatus for Inducing Draught in Boilers of Locomotive, Portable, Traction, and other such Engines.
Year: 1895

page_text: Date of Application, 4th June, 1895
Complete Specification Left, 3rd-Mar.,-1896-Accepted, 4th Apr., 1856
PROVISIONAL SPECIFICATION.
Improvements in Blast Pipes or Apparatus for Inducing Draught
in Boilers of Locomotive, Portable, Traction, and other such
Engines.
I, JOHN JONES, of Upper Lodge, Cyfarthfa Castle Merthyr Tydfil in the
County of Glamorgan, Foreman Engineer of Locomotives, do hereby declare the
nature of this invention to be as follows:-
My invention has reference to an improved construction of blast pipe or draught
inducing apparatus of the kind through which exhaust steam from the cylinders of
a locomotive, portable, traction or other such engine is caused to pass and whence
it is so projected into the chimney as to induce a powerful draught through the flue
tubes of the engine boiler.
My improved apparatus for this purpose, which may be constructed in one piece
or in parts secured together of cast iron or other suitable metal or metals (it may
be made partly of wrought iron) comprises a pipe whose bore tapers slightly from
the bottom towards the top more or less according to the draught required, and
outside of this pipe a jacket extending partly round the pipe for the greater
portion of its length and entirely around the pipe at its upper part, the wall of the
jacket forming an aunular space around the upper part of the pipe and extending
somewhat above it. The wall of the jacket at the deeper side is pierced or formed
with a number of holes and the blast pipe is arranged with these holes towards
the boiler tube plate. With such an apparatus, steam issuing from the engine
cylinders through the blast pipe will cause an upward draught in the annular space
surrounding the upper part of that pipe exhausting air from the smoke-box
through the holes in the wall of the jacket aud producing as nearly as may be a
uniform partial vacuum practically throughout the smoke box, thus tending to keep
the bottom tubes of the boiler free from dust as well as the top tubes, while the
engine is working, thus obviating the necessity of scraping and brushing out the
tubes, to increase the effective heating surface of the boiler and thereby to
economise fuel. Furthermore the use of my invention will tend to reduce wear
and tear of the boiler tubes, and render such wear and tear more uniform, to
promote better distribution of heat in the boiler, to diminish back pressure on the.
pistons and to effect a saving of fuel by reduction of the draught caused by the
softening of the exhaust steam through the exhaust pipe, lessening the tendency to
throw out sparks, and thereby reducing the risk of fire from this cause to
surrounding property.
Dated this 4th day of June 1895

page_text: Improvements in Blast Pipes or Apparatus for Inducing Draught
in Boilers of Locomotive, Portable, Traction, and other such.
Engines.
I, JOHN JONES, of Upper Lodge, Cyfartha Castle, Merthyr Tydfil, in the
County of Glamorgan, Foreman Engineer of Locomotives, dc 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:
My invention has reference to an improved construction of blast pipe or draught
inducing apparatus of the kind through which exhaust steam from the cylinders
of a locomotive, portable, traction or other such engine is caused to pass and
whence it is so projected into the chimney as to induce a powerful draught through
the flue tubes of the engine boiler, as I shall now proceed to explain by the aid of
the accompanying drawings, wherein,
Fig. 1 is an elevation; Fig. 2 a vertical section on the line of Fig. 1; Fig. 3
a plan, and Fig. 4 a horizontal section on the line y y of Fig. 2, showing a blast
pipe or draught inducing apparatus constructed according to this invention.
Fig. 5 is a sectional elevation, to a smaller scale, showing my apparatus. in
position in the smoke box of a boiler of locomotive type.
My improved apparatus, which may be constructed in one piece, as shown, or in
parts secured.together, of cast iron or other suitable metal or metals (it may be
made partly of wrought iron), comprises a pipe 1 whose bore tapers slightly from
the bottom towards the top, more or less according to the draught required, and
outside of this pipe a jacket extending partly round the pipe 1 for the greater
portion of its length and entirely around the pipe at its upper part 1", the wall 2
of the jacket forming an annular space 3 around the upper part of the pipe, and
extending a short distance above it. The cross sectional area of the jacket
preferably increases gradually from the lower partly annular portion up to the
annular portion 3 as shown, thus the suction produced all around the latter by the
action of the steam escaping from the pipe can be effectually utilized. The upper-
end of the wall of the jacket may also advantageously be slightly contracted as
shown. The wall of the jacket at the deeper side is pierced or formed with a
number of holes. 4, preferably of conical form, and the blast pipe is arranged with
these holes towards the boiler tube plate 5 (Fig. 5), the uppermost holes being
below the top of the pipe 1. In practice have obtained good results by arranging
that the uppermost holes 4 should be about five inches from the upper end of the
jacket wall 2 and that this end should be about two inches above the upper end of
the pipe 1. The bottom of the jacket is open at 3ª the lower edge of the jacket
wall being preferably flared as shown. I find it advantageous to gradually reduce
the thickness of the pipe 1 and jacket wall 2 at their upper ends as shewn.
With such an apparatus, exhaust steam issuing from the engine cylinders 6
through the blast pipe 1 will cause an upward draught in the annular space 3
surrounding the upper part of that pipe, thereby exhausting air from the smoke-
box through the holes 4 in the wall of the jacket 2, and producing, as I have found,
a partial vacuum uniform or approximately so practically throughout the smoke
box 7, thus tending, whilst the engine is working, to keep the bottom tubes 8 of
the boiler 9 free from dust as well as the top tubes, and so obviating or reducing
the necessity of scraping and brushing out the tubes, to increase the effective
heating surface of the boiler and thereby to economise fuel. Furthermore I have
found that the use of my invention tends to reduce wear and tear of the boiler
tubes and fire box plates, and to render such wear and tear more uniform; to
promote better distribution of beat in the boiler, and, in consequence of the more

page_text: uniform draught produced in the bottom tubes 8, permits of the use of a blast pipe
of larger diameter than usual for a given size of engine, whereby the terminal
pressure of the exhaust steam escaping from such blast pipe is softened or reduced
so that the back pressure on the engine pistons is diminished and an appreciable
saving of fuel effected. The reduction of the draught caused by the softening of
the exhaust steam passing through the exhaust pipe, also has the effect of lessening
the tendency of the draught to throw sparks-out of the chimney 10, thereby
reducing the risk of fire, from this cause, to surrounding property.
Draught inducing apparatus such as described can be used in the smoke boxes of
marine boilers, the exhaust steam passed through the blast pipe being obtained from
any available source, as for example from auxiliary engines.
Having now particularly described and ascertained the nature of the said.
invention and in what manner the same is to be performed I declare that what I
claim is :-
1. A blast pipe or apparatus for inducing draught, comprising a pipe such as 1
for the passage of steam and a jacket open at top whose wall extends beyond the
top of the pipe 1 and has holes formed through a part of it located below the top.
of the pipe 1 but only partly around that pipe substantially as herein described
for the purpose specified.
2. A blast pipe or apparatus for inducing draught, comprising a pipe 1 for
passage of steam and a jacket extending partly around the said pipe for the greater
portion of its length and entirely around such pipe at its upper part, the wall of
the jacket at the deeper side having formed through it a number of holes,.
substantially as herein described for the purpose specified.
3. My improved blast pipe as described and shown for the purpose specified.
Dated this 2nd day of March 1896.
W. Lloyd Wise,
JOHN JONES.
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.