IMPROVEMENTS IN CONDENSERS FOR STEAM ENGINES
Year: 1870

page_text: LETTERS PATENT to John Walker McCarter, of the City Saw Mills,
Foyle Street, Londonderry, in the County of Londonderry, Ireland,
for the Invention of "IMPROVEMENTS IN CONDENSERS FOR STEAM ENGINES."
Sealed the 31st December 1870, and dated the 12th July 1870.
PROVISIONAL SPECIFICATION left by the said John Walter McCarter
at the Office of the Commissioners of Patents, with his Petition,
on the 12th July 1870.
I, JOHN WALKER MCCARTER, of the City Saw Mills, Foyle Street,
Londonderry, in the County of Londonderry, Ireland, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN CONDENSERS FOR
STEAM ENGINES," to be as follows, that is to say :-
This Invention relates to steam engine condensers of the kind
described in the Specification of certain Letters Patent already obtained
by the present applicant, and dated 20th April 1869 (No. 1222). A
condenser of the kind referred to is constructed in two compartments,
with valves arranged and worked so that the water and air may be
discharged from one compartment whilst its communication with the

page_text: other compartment or with the exhaust pipe of the engine is tem-
porarily closed and without interrupting the condensation of the steam
from the engine.
The present Invention consists mainly in making the discharge valves
of the two compartments of the condenser automatic instead of having
them opened periodically by cams or wipers actuated by the engine.
With this object the said valves are held up against their seats by
springs or by counterbalancing weights, which springs or weights are
adjusted so as to yield and allow each valve to open temporarily when
a certain weight of water has accumulated above it, and when the
external atmospheric pressure is not at the moment tending to keep
it closed. Springs or weights may be applied to the valves in various
ways.
In one modification each valve is a plain disc valve with a central
spindle passing up through a bridge or grating, up against which the
valve closes and a spiral spring is applied (inside the compartment)
between the bridge or grating and a screw nut on the upper end of the
spindle.
In a second modification each valve spindle is extended up through a
stuffing box in the top of the compartment, so that the spring can be
applied and adjusted externally.
By a third modification each valve is fixed to a horizontal spindle
and is closed by an angular motion, the spindle passing out through a
stuffing box and having a lever fixed on it externally, to which the spring
is applied.
In other modifications a counterbalance weight is applied to each
valve by means of a lever arranged as in the third modification, or
by means of a lever acting on the central spindle of the disc form of
valve.
Another improvement consists in applying what is known as a
reducing valve to the pipe for admitting steam to blow out air from
the condenser. Steam of very little pressure above that of the atmo-
sphere will suffice to blow out the air, and by using steam of the lowest
effective' pressure for that purpose not only is the steam economised but
a better vacuum is secured.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Walter McCarter in the Great Seal Patent
Office on the 10th January 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
WALKER MCCARTER, of the City Saw Mills, Foyle Street, Londonderry,
in the County of Londonderry, Ireland, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twelfth day of July, in the year of our
Lord One thousand eight hundred and seventy, in the thirty-fourth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said John Walker McCarter, Her special licence
that I, the said John Walker McCarter, my executors, administrators,
and assigns, or such others as I, the said John Walker McCarter,
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 CONDENSERS FOR STEAM ENGINES," upon the condition (amongst others)
that I, the said John Walker McCarter, my executors or administrators,
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 performed,
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 John Walker McCarter, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and by
the following statement in writing, reference being had to the accom-
panying Drawings, that is to say :-
My said Invention relates to steam engine condensers of the kind
described in the Specification of certain Letters Patent already obtained
by me and dated 20th April 1869 (No. 1222). A condenser of the kind
referred to is constructed in two compartments with valves arranged
and worked so that the water and air may be discharged from one

page_text: compartment whilst its communication with the other compartment
or with the exhaust pipe of the engine is temporarily closed and
without interrupting the condensation of the steam from the engine.
My present Invention consists mainly in making the discharge valves
of the two compartments of the condenser automatic instead of having
them opened periodically by cams or wipers actuated by the engine.
With this object the said valves are held up against their seats by
springs or by counterbalancing weights, which springs or weights are
adjusted so as to yield and allow each valve to open temporarily when
a certain weight of water has accumulated above it, and when the
external atmospheric pressure is not at the moment tending to keep
it closed.
And in order that my said Invention and the manner of performing
the same may be properly understood, I hereunto append a Sheet of
explanatory Drawings, to be herein-after referred to and representing a
modification of the condenser as made with my present improvements.
Figure 1 of the accompanying Drawing is a vertical section of a
steam engine condenser as constructed or arranged with my improve-
ments, and Figure 2 is a sectional plan as with the upper part removed.
In carrying out my Invention the condensation is effected by injecting
cold water, and the condenser is made in two compartments 1, 2. The
exhaust pipe 3 from the engine communicates with the top of the first
compartment 1, and this has at its bottom a grated opening 4 provided
with a valve 5 and leading into the second compartment 2, whilst the
latter has at its bottom a grated opening 6 provided with a valve 7 and
leading into the waste pipe 8. The valves 5 and 7 are metal discs
covered with vulcanised rubber on their upper sides to close up against
the under sides of the grated openings 4 and 6, and the discs have
fixed to them spindles 9, 10, which pass up through the centres of the
`gratings and have spiral springs 11, 12, applied to them in such a way
as to tend to lift the valves 5, 7, up to the gratings. These springs 11, 12,
rest upon the gratings, and their upper ends press up against washers
fixed on the upper ends of the spindles by screw nuts, by means of which
screw nuts the action of the springs is nicely adjusted. Both com-
partments 1, 2, are fitted with rose nozzles 13, 14, for the injection of
cold water, but whilst one 13 in the upper compartment is always open
the other 14 in the lower one is generally closed by a valve 15. The
lower compartment 2 is provided with two other valved inlets 16, 17,
.

page_text: as best seen in the plan Figure 2, one 16 being for air and the other
17 for steam. The three valves 15, 16, 17, are by preference equi-
librium valves, and are opened at proper times by cams, such as the
one 18, shown in Figure 1, on a horizontal shaft 19, which is made to
revolve by gearing from the main shaft of the steam engine. Both
compartments 1, 2, are fitted with snifting valves 20, 21, for the escape
of air, these valves being simple hinged lids which open outwards
whenever the internal pressure is greater than that of the atmosphere.
The upper compartment 1 acts like an ordinary injection condenser,
and the water due to the condensation of the steam from the engine
accumulates in it along with the injection water until its weight is
sufficient to overcome the spring 11 and open the upper valve 5, which
it does when there is a vacuum in the lower compartment 2. The water
which on the opening of the valve 5 passes to the lower compartment 2,
is got rid of from the latter by opening the air valve 16, whereupon
the atmospheric pressure on the under side of the lower valve 7 being
thus counterbalanced the water opens that valve by its weight and
passes into the waste pipe 8, the valve of course closing again by the
action of its spring 12. The air valve 16 is then closed and the steam
valve 17 opened, the steam blowing the air out of the compartment 2
by the snifting valve 21, and filling the compartment.
An important feature of my present Invention consists in causing the
steam which enters by the valve 17 to first pass through a valve of the
kind known as a reducing valve. Steam of much less pressure than
that used for working the engine will effectively displace the air from the
compartment 2, and by using steam of as low a pressure as will answer
not only is there great economy effected in the weight of steam used,
but also the vacuum is more rapidly and casily obtained. A pressure of
one to five pounds above the atmosphere will generally suffice. The
steam admitted to displace the air is in its turn condensed by admitting
a little cold water by the valve 15, and the lower compartment 2 is
thereby restored to a condition to receive a fresh charge of water from
the compartment 1 above. The series of actions need not be repeated
at each stroke of the engine, on the contrary it will generally be better
to make the compartments 1, 2, sufficiently large to allow several
strokes of the engine to take place between cach discharge of the
water. Springs or weights may be applied to the valves 5, 7, in
various ways.

page_text: In a modification differing from that shown on the Drawing cach
valve spindle is extended up through a stuffing box in the top of
the compartment, so that the spring can be applied and adjusted
externally.
By a third modification each valve is fixed to a horizontal spindle,
and is closed by an angular motion, the spindle passing out through
a stuffing box, and having a lever fixed on it externally, to which the
spring is applied.
In other modifications a counterbalance weight is applied to each
valve by means of a lever arranged as in the third modification, or
by means of a lever acting on the central spindle of the disc form of
valve.
Having thus particularly described my said Invention, and the manner
in which the same is to be performed, I have to state that I do not
restrict myself to the precise details herein described or delineated, but
that what I believe to be novel and original, and claim as the Invention
secured to me by the herein-before in part recited Letters Patent is,―
1. The rendering of the condenser discharge valves 5, 7, automatic by
means of springs or weights as herein-before described.
ઃ
2. The regulating of the steam admitted to the lower compartment 2
by means of a reducing" valve so that a minimum quantity may be
used, as herein-before described.
In witness whercof, I, the said John Walker McCarter, have
hereunto set my hand and seal, this 9th day of January, in the
year of our Lord One thousand eight hundred and seventy-one.