Improved Method of and Apparatus for Re-heating Exhaust Steam.
Year: 1896

page_text: Date of Application, 29th Dec.,. 1896-Accepted, 17th Apr., 1897
COMPLETE SPECIFICATION.
Improved Method of and Apparatus for Re-heating Exhaust Steam.
We, OSCAR DUNREATII MCCLELLAN, Inventor, of No. 1240 South Forty-
seventh Street, WILKINSON THOMAS GIRLING, Mechanical Engineer, of
Southwest Corner of Kensington and Lehigh Avenues, JOHN JOSEPH TORPEY,
Builder, of York Road near Hunting Park Avenue, and ROBERT CHARLES
CUNNINGHAM, Merchant, of Southwest Corner of Kensington and Lehigh
Avenues, all in the City and County of Philadelphia, State of Pennsylvania,
United States of America, 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:-
The object of our invention is to provide a method of and means for treating
exhaust steam as it is discharged from the cylinder of a steam engine, to the end
that auch steam may be returned to the engine under conditions of the highest
efficiency and witli as great uniformity and regularity as though it were conducted
thereto directly from the boiler, and this without the expenditure of the force that
has heretofore heen required to expel or expand the exhaust steam to the
atmosphere.
In carrying out our invention, ive conduct the exhaust steam direct from the
cylinder to an air-tight chamber, or chambers, and therein subject it to an electric
flash heat, thereby instantaneously raising the pressure of the steam, in which
condition it is returned to the engine for service, all as will be hereinafter fully
described and claimed.
In the annexed drawings-
Figure 1 is a front elevation of a boiler and steam engine embodying our
invention;
Figure 2 is a side elevation of the engine;
Figure 3 is a vertical section through the re-heater;
Figure 4 is a similar section, as on the line - of Figure 3;
Figure 5 is a plan with the switch-box in section;
Figure 6 is a detail plan as on the line ww of Figure 4;
Figure 7 is a horizontal section as on the line y-y of Figure 4;
Figure 8 is a diagram of the electrical connections.
A represents a steam boiler, B a steam engine, and C steam re-heating
structure adjacent thereto. This structure is preferably, though not essentially, in
the form of a rectangular casing divided into four air-tight compartments or
chambers 1, 2, 3 and 4, in each of which is supported a series of electric resistance
coils 5 electrically connected with a suitably disposed dynamo 6, whereby the coils
may be instantaneously and successively heated to a state of incandescence for the
purpose below described. In the top and bottom of the structure are formed valve
boxes 7 and 8, respectively, in each of which is formed a chamber (7" 8) with which
communicate ports 9 and 10 from the respective re-heating chambers. The upper
ports 9 comprise vertical portions 11 which open directly into the several re-heating
chambers and are provided with lateral branches 12 leading to the chamber 7.
Communicating with this chamber and with the vertical port portions 11, at
a point above the branch ports 12, are horizontal ports 13. The lower ports 10
comprise vertical portions 11 provided with lateral branches 12", 12, that lead to
the chambers and the port 8%, respectively. Leading from the lower ends of the

page_text: port portions 11 to the chambers 1, 2, 3, & 4 are horizontal ports 13. Opening
into the chamber 8" is a pipe 14 which has communication with the exhaust of the
steam engine, while opening into the upper chamber 7 is a pipe 15 leading to the
steam chest of the engine. Fitted to the vertical portions of each of the ports 9 is
a piston valve 16, the stem 17 of which rises through a suitable stuffing box on the
top of the casing, and is provided with an extension 18 that is fitted to and guided
in a head 19 affixed to the pipe 15. This extension also extends through a
perforation in a disc 20 which is rotatably mounted on said pipe 15 a suitable
distance below the 'fixed' head, and which extension is provided with wedges or
cams 21 which co-act with said disc as will presently appear. Bearing against the
head 19 and against a collar or shoulder on each of the extensions is a spiral
spring 21, the tendency of which. is to maintain the stem normally depressed, and
thereby sbut off communication between the re-heating chamber and the chamber 7.
To the upper or free end of each of the extensions is affixed the blade 22 of
an electrical switch, the clips 23 thereof being supported upon the head in. such
manner that when the valve stem is raised the blade is instantly disengaged' from
the clips and when said stem is depressed the blade is correspondingly engaged
with the clips.
To each of the lower ports 10 is fitted a piston valve 16, the stem 17 of which
depends through appropriate stuffing boxes on the bottom of the casing. The stem
extends through a fixed head 19 on the pipe 14, a spring 21 being provided which
acts normally to raise the valve and shut off the communication between the
re-heating chamber and the chamber 8. On the lower or free end of each of the
stems 17 is a blade 22" which co-acts, similarly to that on the upper valve stem
with clips 23 on the lower head, that is'to say, when the valve is in its normal or,
closed position the blade is in action and when the valve is in its depressed or open
position the blade is disengaged from the clips.
The electrical convections will be more clearly understood by reference to the
diagram, Figure 8, wherein it will be observed that the positive wire from the
dynamo is connected with the swinging contact arin 24 of a rheostat, thence from
the resistance plates 25 of the rheostat to plates 26 connecting the inner clips of the
udjacent switches on the upper head 19, the outer' clips tliereof being connected
with the respective resistance coils of the re-heating chambers, the opposite ends of
said coils being connected to the outer clips 23 of the switches on the lower
bead 19ª, and the return wire to the dynamo being connected with the plates 26*
connecting the inner clips of said switches.
The contact arm 24 of the rheostat is provided with a crank arm 27 that. is
connected by means of a link 28 with the governor head 29 of the steam engine, to
the end that the governor balls as they raise or lower the head during the operation
of the engine, will actuate the contact arm to regulate the resistance in a manner
to increase or diminish the temperature in the chambers proportionally with the
speed of the engine.
Leading from the steam boiler A is a pipe 30 provided with a safety valve 31
and leading from this pipe to the steam chest of the engine is a branch pipe 32
provided with a check valve 33 and with throttle valves 34. The discharge
pipe 15 communicates with the pipe 32 intermediate the throttle valves. Leading
from the pipe 30 somewhat below the pipe 32 is a pipe 35 to which are connected
four pipes 36 leading to the chambers 1, 2, 3, 4, respectively, which latter pipes are
each provided with a safety valve 37. The lower extension of the pipe 30. is
connected with the pipe 14, and is also equipped with a check valve 33. The
pipes 14 and 30 are connected by means of a three-way cock 38.
The operation is as follows:-
At the outset a fire is started in the furnace below the boiler, and steam' is
raised to low pressure. The throttle valves 34, 34 then being opened, the steain
passes from the boiler to the steam chest of the engine and the latter is thereby
set in operation. While starting the engine, the engineer opens the valve 38 ou
the exhaust pipe, and, at the same time, starts up the dynamo. When sufficient

page_text: energy has been generated, to bring; the coils to a state of incandescence sufficient
to heat the exhaust, steam that may be conducted to one of the chambers, say
chamber 1, the valve 38 is closed, and the valve on the pipe leading to the
chamber 8 is opened, the exhaust steam thus flowing to such chamber from the
steam chest of the engine. The valves on the. remaining pipes will be maintained
closed, but at the next stroke of the engine, the valve port leading to chamber, 2
will be opened, and that' chamber supplied with exhaust steam. In the following
stroke of the engine the valve port leading to the chamber 3 will be opened, and
that chamber will be charged with exhaust steam. At this stage the steam in
chamber 1 will have been raised to high pressure and will raise and open the
valve at the top of said chamber, enter the chamber 7 and pass by way of the
pipe 15 to the live steam pipe 32, thence to the steam chest of the engine.
The exhaust will then be permitted to pass from the engine to chamber 4.
When the valve at the top of chamber 1 is raised by the high pressure of the
steam, as just stated, the cam 21° on the valve stem will bear against the edge of
the opening in the disc 20, thereby slightly turning the latter, the openings
through which pass the other valve stems, thus being shifted to check the
underlying stops on the stems from passing through such openings, and thus
preventing the valves in the remaining chambers 2, 3 and 4 from opening until the
next.stroke of the engine. At that time the pressure will be equal on the top and
bottom of the discharge valve of chamber 1, the spring thus depressing the valve
stem and moving the cam thereon below the opening in the disc, whereupon the
steam in the next chamber 2, having been raised to high pressure, will open the
discharge valve and escape to the steam chest. At the same time the head will be
shifted to lock the other valves in the depressed or closed position, and. the
operation of introducing the steam to the chambers successively, reheating, it
therein and discharging the same to the steam chest of the engine will be carried
on continuously.
:
The function of the ports 13 is to permit the pressure of the exhaust steam
immediately upon its introduction to the successive chambers 1, 2, 3 and 4, to
act against the undersides of the respective valves 16", thus equalising the pressure
upon the top and bottom of the valves and permitting their respective springs 21"
to raise the same in a manner to cut off the communication between the
chamber 8 and said chambers 1, 2, 3 and 4 in succession.
It will be obvious that the rapid flashing of the heat in the successive air tight
chambers will instantaneously raise the pressure of the steam therein in rapid
succession, to the end that such steam will be returned to the engine under
conditions of the highest efficiency and with as great uniformity and regularity as
though it were conducted directly thereto from the boiler. It will also be
obvious that as the steam is introduced to and reheated in air-tight chambers
the benefit of a vacuum, EU to say, is secured, thereby obviating and
utilising the force heretofore required to expel or expand the exhaust steam to
the atmosphere...
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. The method of treating exhaust steam, which consists in providing a suitable
air-tight chamber, supplying exhaust steam thereto, subjecting the steam within
the chamber to an electric Hash heat, and then returning the steam to the engine
for service, substantially as described.
2. The combination, with a steam-engine, of a heating chamber, means whereby
the exhaust steam from the engine is delivered to said chamber, electrical heating
devices in said chamber, and means whereby the reheated steam in said chamber
is returned to the engine, substantially as described.
3. The combination, with a steam engine, of a heating chamber, means whereby
the exhaust steam from the engine is delivered to said chamber, means for

page_text: producing an electrical flash heat in said chamber, and means whereby
the re-heated steam in said chamber is returned to the engine, substantially as
described.
4. The combination, with a steam engine, of a series of heating chambers, means
whereby the exhaust steam from the engine is delivered to the successive
chambers, means for producing an electrical (flash heat in said chambers, and means
whereby the re-heated steam in the successive chambers' is returned to the engine,
Bubstantially as described.
5. The combination, with a steam engine, of a series of heating chambers, means
whereby the exhaust steam from the engine is delivered to said chambers, valves
to control such delivery, resistance coils in said chambers, switch devices for
controlling the passage of the electrical current thereto at predetermined intervals,
and means whereby the re-heated ateam in the successive chambers is returned' to
.the engine, substantially as described.
6. The combination, with a steam engine, of a series of heating, chambers,
ingress and egress pipes providing communication between said chambers and
the steam engine, valves controlling the communication between said pipes and the
chambers, means for locking and releasing said valves at predetermined intervals,
electrical resistance devices in said chambers, a source of electric energy,
and electrical connections between the same and said devices, substantially as
.described.
7. The combination, with a steam engine, of a series of heating chambers,
ingress and egress pipes providing communication between said chambers and the
steam engine, valves controlling the communication between said pipes and the
chambers, meaus for locking aud releasing said valves at predetermined intervals,
electrical resistance devices in said chambers, switches connected with
said valves and resistance devices, a source of electric energy, and electrical
connections between the same and said switches, substantially as described.
8. The combination, with a steam engine of a series of heating chambers,
ingress and egress pipes providing communication between said chambers and the
steam engine, valves controlling the communication between said pipes and the
chambers, means for locking and releasing said valves at predetermined intervals,
electrical resistance devices in said chambers, a source of electric energy, and
electrical connections between the same and said devices, together with a
rheostat and controlling devices therefor between the same and the governor of
the engine, substantially as described.
Dated this 28th dow of December 1900
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicants.