IMPROVEMENTS IN VARIABLE EXHAUST APPARATUS FOR LOCOMOTIVE ENGINES
Year: 1874

page_text: LETTERS PATENT to Robert John Hood, of the City of Manchester,
in the County of Lancaster, for the Invention of "IMPROVEMENTS IN
VARIABLE EXHAUST APPARATUS FOR LOCOMOTIVE ENGINES."-A communi-
cation from abroad by Orlando Stewart, of the Town of East
Cambridge, County of Middlesex, and Commonwealth of Massa-
PROVISIONAL SPECIFICATION left by the said Robert John Hood at
the Office of the Commissioners of Patents, with his Petition, on
the 13th October 1874.
I, ROBERT JOHN Hood, of the City of Manchester, in the County of
Lancaster, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN VARIABLE EXHAUST APPARATUS FOR LOCOMOTIVE ENGINES,"
(a communication to me from abroad by Orlando Stewart, of the Town
of East Cambridge, County of Middlesex, and Commonwealth of
Massachusetts, United States of America,) to be as follows:-

page_text: intensity of the exhaust of locomotive engines, and relates to apparatus
for this purpose in which moveable flaps, wings, or portions of a nozzle
are arranged in a containing case in conjunction with arms, connections,
and levers, for enabling the said flaps or wings to be operated by-the
driver or attendant from his post, as required for varying the size of the
nozzle for the time being.
One arrangement consists in making the flaps, wings, or moveablo
portions of the nozzle of a circular section or nearly so, and sufficiently.
elastic to cause them to spring out against the sides of the containing case
with which they are combined, so that they shall be enabled to scrape off
the matter which would otherwise accumulate and obstruct their motion.
The exhaust pipe is surmounted by a box or casing which incloses and
surrounds the exhaust nozzle. The latter is made in two parts or flaps
which are hinged to the bottom of the box. These flaps are made of
sheet metal, are of circular cross section or nearly so, and sufficiently
elastic to enable them to spring out or expand against the sides of the
box, they are also made conical that their inclined edges may correspond
with the pyramidal sides of the case, the inclined edges are also
chamferred that they may make a tight fit with the sides of the box,
and also that they may remove any incrustation which may be formed
thereon, the elasticity or spring of the metal of which they are composed
enabling them to slide over any such matter when they are drawn back
or opened, and to shear it off when they are closed or brought together
again, the friction between the edge of the flaps and box serving to keep
these edges always sharp, and the joint between them and the box tight.
Were these flaps cast rigid and without spring or elasticity, they would
soon become clogged by concrete matter, which might still form to some
extent though not so rapidly as in those cases where the flaps or moving
parts were exposed upon one side to the influences of the fire, for it is
obvious that these flaps being surrounded on all sides by their con-
taining case, will be in a great measure protected from the effects of
the fire..
To each of the two halves of the nozzle is jointed by means of an
intermediate link an arm attached to one of two shafts, which two shafts
are so connected by jointed levers that they shall partake of each other's
motions. A lever secured to one of the shafts is by means of suitable
connecting rods operated by the driver, who is thus enabled to expand or
contract his exhaust as required.

page_text: In another arrangement the casing has preferably a rectangular
horizontal shape at its base from whence its sides extend vertically
upward in parallel lines, while its ends at a point about one-third of the
distance from their lower to their upper ends are curved outward, and
then upward so as to increase longitudinally and horizontally the
dimensions of said casing. Passing vertically upward through the
centre of the casing from its lower end to the outward swell of the ends,
is an opening having a slightly diminishing size upward and having its
corners rounded, while from the point where said ends swell outward to
the upper end of said casing, said opening is rectangular in shape and
conforms to the increase in size of the same. Fitted to or within the
recesses formed by the enlargement of the opening are two flaps or
wings, which correspond to and fill said recesses so as to complete the
sides of said opening upon a line with its lower portion, the inner faces
of said flaps or wings being formed upon the same circle as the
contiguous lower sides of said opening.
In order that the size of the upper end of the opening may be
diminished at will, the lower ends of the flaps or wings are pivoted to or
upon the sides of the casing, so as to permit the upper ends of said flaps
or wings to be moved toward or from each other, and enable the space
between the same to be diminished or incrcased in a corresponding
degree. Journalled horizontally within suitable bearings secured to or
upon the rear side of the casing is a shaft provided upon each end
immediately outside of said bearings with a double arm. Pivoted within
the upper end of each arm is one end of a flat bar, which from thence
extends forward and has its opposite end pivoted to or upon the upper
end of the adjacent flap or wing. Similar connecting bars extend
upward and forward from the lower ends of the before-mentioned arms,
and are in like manner pivoted to the upper end of the forward flap or
wing. As thus arranged it will be seen that by rotating the shaft at the
rear side of the casing rearward, the upper ends of the pivoted flaps or
wings will be moved apart, and that by rotating said shaft in an opposite
or forward direction, said wings will be correspondingly moved toward
each other.
The device as constructed is placed in the usual position withing the
chimney of a locomotive, with the actuating shaft at its rear side and
extending transversely across the engine, the outer end of said shaft
being projected beyond the chimney sufficiently to enable it to receive a

page_text: crank arm, from which a rod is extended rearward to within convenient
reach of the driver or attendant, who is thereby enabled at will to
quickly and easily change the size of the exhaust opening, and corre-
spondingly vary the force and velocity of the exhaust steam.
The especial advantages obtained by this construction and arrange-
ment of parts, are ease and efficiency of operation combined with great
strength and durability, in addition to which the device can be furnished
at a comparatively small cost.
SPECIFICATION filed in pursuance of the conditions of the Letters
Patent, and of an Order of the Lord Chancellor, by the said Robert
John Hood in the Great Seal Patent Office on the 21st April 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
JOHN HOOD, of the City of Manchester, in the County of Lancaster,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirteenth day of October, in the
year of our Lord One thousand eight hundred and seventy-four, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Robert John Hood, Her
special license that I, the said Robert John Hood, my executors,
administrators, and assigns, or such others as I, the said Robert
John Hood, 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 Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention
for "IMPROVEMENTS IN VARIABLE EXHAUST APPARATUS FOR LOCOMOTIVE ENGINES,"
(a communication to me from abroad by Orlando Stewart, of the Town
of East Cambridge, County of Middlesex, and Commonwealth of
Massachusetts, United States of America,) upon the condition (amongst
others) that I, the said Robert John Hood, my executors or admini-
strators, by an instrument in writing under my, 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 per-

page_text: formed, and cause the same to be filed in the Great Seal Patent Office
within six calendar months next and immediately after the date of
the said Letters Patent.
NOW KNOW YE, that I, the said Robert John Hood, 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 thereof, and the Drawings therein referred
to (that is to say) :-
:-
This Invention is designed to provide improved means for varying the
intensity of the exhaust of locomotive engines, and relates to apparatus
for this purpose in which movable flaps, wings, or portions of a nozzle are
arranged in a containing case in conjunction with arms, connections, and
levers for enabling the said flaps or wings to be operated by the driver
or attendant from his post, as required for varying the size of the nozzle
for the time being.
On Sheet 1 is illustrated an arrangement of double exhaust, Fig. 1
being a plan view of the upper side of the apparatus, Fig. 2 a side
elevation of the same, Fig. 3 a vertical cross section on the line x, x, of
Fig. 1, and Fig. 4 a vertical longitudinal section on the line y, y, of
Fig. 1.
The casing has a central vertical division B* so that it forms
practically two casings, whose ends C at a point about one-third of the
distance from their lower to their upper ends are curved outward and
then upward, so as to increase longitudinally and horizontally the
dimensions of each casing. Passing vertically upward through the centre
of each casing from its lower end to the outward swell of the ends C is
an opening D having a slightly diminishing size upward, and rounded,
while from the point where the said ends swell outward to the upper
end of said casing, said opening is rectangular in shape and conforms to
the increase in size of the same, as shewn in Fig. 3. Fitted to or within
the recesses formed by the enlargement of the opening D are two flaps
or wings E, which correspond to and fill said recesses so as to complete
the sides of said opening upon a line with its lower portion, the inner
faces of said flaps or wings being formed upon the same circle as the
contiguous lower sides of said opening.
In order that the size of the upper end of the opening D may be
diminished at will, the lower ends of the flaps or wings E are pivoted to

page_text: or upon the sides B of the casing, so as to permit the upper ends of said
flaps or wings to be moved toward or from each other, and enable the
space between the same to be diminished or increased in a corresponding
degree. Journalled horizontally within suitable bearings F secured to or
upon the rear side of the casing is a shaft G provided upon each end
immediately outside of said bearings, with a double arm H. Pivotted
within the upper end of each arm is one end of a flat bar I, which from
thence extends forward and has its opposite end pivotted to or upon the
upper end of the adjacent flap or wing. Similar connecting bars K
éxtend upward and forward from the lower ends of the arms H, and are
in like manner pivotted to the upper end of the forward flap or wing.
As thus arranged it will be seen that by rotating the shaft G rearward,
the upper ends of the pivotted flaps or wings will be moved apart, and
that by rotating said shaft in an opposite or forward direction, said wings
will be correspondingly moved toward each other.
The device as constructed is placed in the usual position within the
chimney or smoke box of a locomotive, with the actuating shaft G at its
rear side and extending transversely across the engine, the outer end of
said shaft being projected beyond the chimney sufficiently to enable it to
receive a crank arm, from which a rod is extended rearward to within
convenient reach of the driver or attendent, who is thereby enabled at
will to quickly and easily change the size of the exhaust opening, and
correspondingly vary the force and velocity of the exhaust steam.
The especial advantages obtained by this construction and arrange-
ment of parts are ease and efficiency of operation combined with great
strength and durability, in addition to which the device can be furnished
at a comparatively small cost. The parts Ex form coverings to prevent
deposit in the spaces behind the flaps E.
Figs. 5, 6, and 7 (Sheet 2) shew a modification in which the flaps,
wings, or movable portions of the nozzle are made of a circular section
or nearly so, and sufficiently elastic to cause them to spring out against
the sides of the containing case with which they are combined, so that
they shall be enabled to scrape off the matter which would otherwise
accumulate and obstruct their motion. The flaps E in this arrangement
are made of sheet metal, are of circular cross section or nearly so, and
sufficiently elastic to enable them to spring out or expand against the
sides of the casing A, they are also made conical that their inclined
edges E¹ may correspond with the two sides A² of the case, which in this

page_text: arrangement are made pyramidal; the inclined edges are also chamfered
that they may make a tight fit with the sides of the case, and also that
they may remove any incrustation which may be formed thereon, the
elasticity or spring of the metal of which they are composed enabling
them to slide over any such matter when they are drawn back or opened
and to shear it off when they are closed or brought together again, the
friction between the edge of the flaps and casing or box serving to keep
these edges always sharp, and the joint between them and the casing or
box tight.
The motions of the flaps E will keep, as before explained, the casing
or box clear of all obstructions along the joints E¹, and the force of the
blast will tend at all times to close the joint at this point, and should any
steam leak at this point or at i beneath the flaps of the nozzle, it will
rise through the case A and serve to keep its interior free from cinders
or other obstructions, while its force will all be available with the main
body of the blast, which rises through the interior of the conical
nozzle.
Having described the nature of the said Invention and explained the
manner of carrying the same into practical effect, as communicated to
me as aforesaid I hereby declare that I claim,-
First. The casing composed of the base A*, sides B, ends C, and
combined with the pivoted wings E, E*, when the several parts are
constructed and arranged, substantially as and for the purpose specified.
Secondly. In combination with the elements above-named the shaft G,
double arms H, and connections I and K, substantially as and for the
purpose shewn.
In witness whereof, I, the said Robert John Hood, to this
Specification have set my hand and seal, this Third day of
April, in the year of our Lord One thousand eight hundred and
seventy-five.
ROBERT JOHN HOOD. (L.S.)