Improvements in or relating to Engine Exhaust and Furnace Draught Apparatus.
Year: 1899

page_text: Date of Application, 29th Aug., 1899-Accepted, 28th Oct., 1899
Improvements in or relating to Engine Exhaust and Furnace
Draught Apparatus.
I, JAMES EARLE RANKINE, Brass Founder, of Elk Rapids, in the County of
Antrim, and State of Michigan, one of the United States of America, do hereby
declare the nature of this invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained by the following state-
ment:―
This invention relates to exhaust and draught mechanism for engines, being
particularly designed for use in connection with locomotive engines. The object
of the present invention is to provide what may be termed a visual draft gauge
for the purpose of indicating the amount of draft in the fire-box. It is well
known that in locomotives it is sometimes required to largely increase the power
for a short period of time, and when the steam power is increased, the exhaust
steam is of necessity caused to pass through the contracted exhaust nozzle, thereby
greatly increasing the draft through the furnace, which has a tendency to break
up or disintegrate the fire, ofttimes throwing red-hot coke from the stack, which
is a source of considerable danger to contiguous property. Numerous expedients
have been devised to overcome this difficulty, but in most instances the devices
have been placed within the stack or inside of the smoke arch, where they were
subjected to the hot gases and in a short time rendered useless. It is the object
of this invention to provide means under the ready control of the engineer
whereby the exhaust may be increased or diminished at pleasure, and in con-
nection with this, a draft gauge is employed by which the amount of draft is
visually indicated, thus enabling the engineer to divert as large a quantity of
the exhaust steam from the ordinary exhaust nozzle as may be necessary to
prevent the breaking up of the fire.
The invention consists in certain novel features and details of construction
and arrangement of parts as hereinafter fully described, illustrated in the draw-
ings and incorporated in the claim.
In the accompanying drawings,
Figure 1 is a sectional view of a draft gauge constructed in accordance with
the present invention.
Figure 2 is a diagrammatic view of a locomotive boiler and cab. showing
smoke stack, steam exhaust passage, branch passage for exhaust steam and regu-
lating valve, in section.
Similar numerals of reference designate corresponding parts in both figures.
In carrying out the present invention I employ a draft indicator gauge which
is in the form of a transparent tube indicated at 1, bent in U-shape to comprise
two legs 2 and 3, the bend or curve 4 in the gauge being at the lowermost point
and the legs 2 and 3 extending upward therefrom. Within this tube is placed
a quantity of water or other liquid having the same or a less specific gravity.
The tubular gauge 1 is mounted by means of one or more clips or brackets 5
upon a supporting block or base 6, and connected also to said block or base is a
valve casing 7 having a door 8 for affording access thereto. In one side of the
valve casing 7 is an opening 9 from which a tubular connection 10 extends to and
communicates with one of the legs 3 of the draft indicator. Within the casing
CD

page_text: is a flat or flap valve 11 suspended by a strap 12 and resting lightly over the
opening 9 leading to the pipe 10.
Communicating with the valve chamber 7 is a suction pipe 13, which extends
downward into and communicates with the fire box so that the air contained
therein may be influenced by any partial vacuum which occurs in the fire-box
due to the forcing of the exhaust steam outward through the stack.
The parts
above enumerated are located within the cab under the eye of the engineer, who
can by glancing at the indicator 1, which is graduated exteriorly, note the level
of the liquid in the leg 3 of the gauge and thereby ascertain the amount of
draft.
14 designates the discharge nozzle for the exhaust steam, which is provided
with a contracted discharge end 15 arranged at or near the base of the stack 16.
It will be understood that the discharge nozzle 14 communicates with the exhaust
orifices or ports in the steam cylinders. Extending laterally from the nozzle 14
is a branch nozzle 17 which extends through the shell and outward at one side
of the stack. Within said branch nozzle 17 is arranged a valve 18 which is
mounted upon a central stem 19 which forms the pivot upon which the valve
moves. Connected to the stem of the valve is an arm 20 and connected to said
arm is a contractile spring, attached at its opposite end to a fixed point, the
tension of said spring being exerted to hold the valve closed or in a position in
which it will obstruct the outward passage of exhaust steam. By having the
valve pivoted centrally and diametrically, the pressure of the exhaust steam is
equal on both sides of the fulcrum and therefore there is little tendency to open
the valve, and such tendency is overcome by means of the spring 21. An
operating rod 22 is connected at one end to the arm 20 on the stem of the valve
and passes rearward through and into the cab, where it is provided with a
handle 23, by grasping which the engineer may open or close the valve 18 to the
desired extent. In connection with the rod 22 any suitable means may be used
for holding the rod at any point of adjustment, thereby holding the valve entirely
closed or open or at any intermediate point.
From the foregoing description the operation of the device will be understood.
The exhaust steam passing out through the nozzle 15 causes a suction through
the fire tubes of the boiler and promotes draft in the fire box.
This is pro-
ductive of a partial vacuum in the fire box and such partial vacuum sucks the
air through the tube 13 from the valve chamber 7, thus opening the valve 11
and causing also a partial vacuum in the tube 10 and leg 3 of the draft gauge.
This causes the liquid in the leg 3 to rise, and the greater the draft and con-
sequently the greater the vacuum produced in the fire-box, the higher will the
liquid rise within the gauge. In case the draft becomes too great the engineer,
by operating the rod 22, may open the valve 18 to any desired extent, thus
permitting a corresponding amount of the exhaust steam to pass out through
the branch nozzle 17 directly to the atmosphere without passing upward through
the stack and thereby increasing the draft. In other words, the gauge 1 indi-
cates the amount of draft, and the engineer by means of the rod 22 may set
the valve so as to reduce the draft to any desired extent. The object in pro-
viding the valve 11 is to overcome the pulsations in the draft gauge due to and
caused by the intermittent exhaust of the steam through the discharge nozzle
at the base of the stack, the said valve 11 keeping up a constant vibration as it
is influenced by the intermittent action of the exhaust steam and preventing
the communication of such action of the steam to the liquid contained in the
gauge, but when the engine is stopped will leak sufficient to bring the gauge
to zero in about fifteen seconds.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is: :―
1. In draft indicators for locomotive furnaces in which the draft is accelerated

page_text: by the intermittent action of exhaust steam, the combination of a transparent
U- -gauge, a chamber arranged alongside the gauge, a tubular connection between
one leg of the gauge and the chamber, a valve suspended to hang across the
passage for checking or preventing pulsations in the gauge incident to inter-
mittent exhaust, and a suction pipe leading from chamber to fire box, substan-
tially as described.
2. In a locomotive engine having exhaust mechanism adapted to discharge
through or at one side of the stack, and means for regulating the discharge from
the cab of the engine, the combination with such engine, of a visual indicator
consisting of a transparent U-gauge, a valve chamber communicating with one
leg of the gauge, a suspended flat valve for preventing pulsations in the gauge,
and a suction pipe extending from valve chamber to fire box of the engine, sub-
stantially as described.
Dated this 20th day of A vonat 1000
BOULT, WADE & KILBURN,
Agents for the Applicant.