Year: 1885

page_text: We HENRY ADAMS of 60 Queen Victoria Street in the City of London Civil
and Mechanical Engineer and WILLIAM ADAMS of Nine Elms in the County of
Surrey Locomotive Engineer do hereby declare the nature of this invention to be
as follows:
This invention has for its object improvements in blast pipes for locomotive
engines applicable also to other uses.
The draft in locomotive engines is obtained by the discharge of the exhaust
steam from the cylinders into the chimney through a blast pipe and the steam
discharged at high velocity from the blast pipe induces a current of air through"
the furnace and the tubes of the boiler. By our invention we render the action of
the blast more effectual generally in accelerating the draft and especially we render
it more efficient in increasing the draft through the lower tubes of the boiler where
with the ordinary blast pipe the draft is less rapid than it is through the upper
tubes.
At present the blast is usually discharged through an orifice which is circular in
Bection and consequently the jet of steam issuing from it presents a comparatively
small surface to engage with the products of combustion in the smoke box and so
to carry them to the chimney. We increase this surface by flattening the jet to a
fan like form so that the steam issues in a thin sheet.
'
In addition to this especially if we desire to encourage the lower boiler tubes we
curve the elongated and narrow orifice as it is seen in plan and this curvature may
be carried so far that at and near the top of the blast pipe the ends of the orifice
meet and form a complete annulus whilst lower down the ends remain separate so
as to leave between them an open mouth leading into a cavity from which the
only outlet is through the centre of the annular aperture and the jet issuing
from it. This open mouth consequently is exposed to a powerful suction and it'
is immediately in front of the ends of the lower boiler tubes which it is desired to
encourage.

page_text: Screens may also be provided to ensure that the draft into this mouth shall be
supplied entirely or mainly by the lower boiler tubes. We sometimes provide a
moveable bell mouth to avoid obstruction to the tubes.
These blast pipes reduce back pressure and are useful not only in locomotive
engines but elsewhere when a jet of steam is employed to carry with it air or
products of combustion.
COMPLETE SPECIFICATION.
Improvements in Blast Pipes for Locomotive Engines, Applicable
also to other Uses.
We, HENRY ADAMS of 60 Queen: Victoria Street in the City of London Civil
and Mechanical Engineer and WILLIAM ADAMS of Nine Elms in the County of
Surrey, Locomotive Engineer 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:-
This Invention has for its object improvements in blast pipes for locomotive
engines applicable also to other uses.
The draft in locomotive engines is obtained by the discharge of the exhaust
steam from the cylinders into the chimney through a blast pipe and the steam
discharged at high velocity from the blast pipe induces a current of air through
the furnace and the tubes of the boiler. By our invention we render the action of
the blast more effectual generally in accelerating the draft and especially we render
it more efficient in increasing the draft through the lower tubes of the boiler where
with the ordinary blast pipe the draft is less rapid than it is through the upper
tubes.
At present the blast is usually discharged through an orifice which is circular in
section and consequently the jet of steam issuing from it presents a comparatively
small surface to engage with the products of combustion in the smoke box and so
to carry them to the chimney. We increase this surface by so forming the jet that
the steam issues in a thin sheet.
In addition to this especially if we desire to increase the draft through the lower
boiler tubes we curve the elongated and narrow orifice as it is seen in plan and
this curvature may be carried so far that at and near the top of the blast pipe the
ends of the orifice meet and form a complete annulus whilst lower down is an
open mouth leading into a cavity from which the only outlet is through the centre
of the annular aperture and the jet issuing from it. This open mouth consequently
is exposed to a powerful suction and it is immediately in front of the ends of the
lower boiler tubes the draught through which it is desired to encourage.

page_text: Screens may also be provided to ensure that the draft into this mouth shall. be
supplied entirely or mainly by the lower boiler tubes. We sometimes provide a
moveable mouth to avoid obstruction to the tubes.
These blast pipes reduce back pressure and are useful not only in locomotive
engines but elsewhere when a jet of steam is employed to carry with it air or
|products of combustion.
In order that our said invention may be most fully understood and readily.
carried into effect we will proceed to describe the drawings hereunto annexed.
| products of combustion.
In order that our said invention may be most fully understood and readily.
carried into effect we will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a transverse vertical section of a locomotive engine to which our
improved blast pipe is applied.
Figure 2 is a vertical and longitudinal section of the fore part of the same
engine. The engine here shewn is of the inside cylinder type. Similar views of
an engine of the outside cylinder type are shewn by Figures 3 and 4.
In the arrangement shewn in Figures 1 and 2 the steam passing from both the
cylinders meets at the base of the blast pipe at A. At the lower part the blast
pipe is convex in front and concave in rear where it faces the ends of the boiler
tubes and as the blast pipe rises the curvature of the outer and inner surfaces
increases until at B they meet and the space between them becomes annular. The
steam ascending from A between the two surfaces issues from the upper end of the
blast pipe in the form of a cylindrical or hollow jet. At the lower part of the blast
pipe in front of the lower boiler tubes there is an open mouth C leading into the
cavity of the annular upper part of the blast pipe. The steam in issuing produces
a strong draught through the mouth consisting in great part of the gases issuing
from the lower boiler tubes. The draught of these tubes thus improved and also
generally the draught of the boiler is improved in consequence of the increased
surface given to the jet of issuing steam.. The steam being thus applied more
efficiently to carry forward the products of combustion from the smoke box into
the chimney.
In Figures 3 and 4 the steam is brought from the cylinders by two pipes one
from each cylinder, these unite at the top at B in a double ring and they convey
the steam into the annular space within the ring-In this case the mouth at C is
at the lower end of a moveable piece projecting downwards from the double ring
and as before it faces the lower boiler tubes-As before the steam issuing from
the ring in the form of an annular jet produces a brisk suction through the mouth
and this is supplied by the gases from the lower boiler tubes.
In place of forming the mouth C in a moveable piece as shown a screen or
screens may be otherwise arranged to direct the gases from the lower boiler tubes
into the interior of the annulus.
Although we prefer that the mouth of the blast pipe should form a complete
annulus still the advantages of the invention are in part obtained where it is not
so made. The draught is much improved by forming the mouth of the blast pipe
as a long narrow slit whether this slit be made endless and becomes an aunulus or
otherwise.
Arrangements such as above described for use in locomotives may also
advantageously be applied in traction engines and in portable and like engines
and are applicable in other cases in which it is desired to apply steam to impart
motion efficiently to air or other gases.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is
1. An engine with a blast pipe having an annular orifice and a widely expanded
mouth communicating by a tapering passage with the interior of the annulus;
such mouth facing or being adjacent to the extremities of the lower boiler tubes.

page_text: 2. An engine with a blast pipe having an annular orifice and the widely
expanded mouth communicating with the interior of the annulus so screened as
to cause the gases drawn from the lower boiler tubes to pass mainly or entirely
through the annulus.
3. An engine with a blast pipe having an aperture of annular or elongated form
and so applied as to produce an indraft at a widely expanded mouth facing or
adjacent to the lower boiler tubes.
4. A blast pipe with an aperture of annular form connected by a tapering
passage with a widely expanded mouth facing or adjacent to a tube or channel
from which air or gas is drawn and caused to pass up through the interior of the
annulus.