Improvements in Controlling or Regulating the Communication between a Condenser and a Steam Engine Cylinder during the Ordinary Period of Eduction, and in Apparatus therefor.
Year: 1891

page_text: Date of Application, 3rd Apr., 1891
Complete Specification Left, 1st Feb., 1892-Accepted, 5th Mar., 1892
PROVISIONAL SPECIFICATION.
Improvements in Controlling or Regulating the Communication
between a Condenser and a Steam Engine Cylinder during the
Ordinary Period of Eduction, and in Apparatus therefor.
I, THOMAS MUDD of Central Engine Works, West Hartlepool, in the County
of Durham, Engineer, do hereby declare the nature of this invention to be as
follows:-
Numerous facts observed in my experience lead me to look for economy from a
reduction in the time the cylinder is open to the cold condenser; and it seems to
me the communication can be stopped at a suitable point in the passage, without
causing a detrimental amount of compression and without greatly reducing the
power produced by a given size of engine.
I propose to effect this object, either by inserting in the exhaust pipe a valve of
the throttle, mushroom, slide, sluice or other type, working the valve by one of the
working parts of the engine in such a way that the passage shall be open when the
main valve of the engine "releases," but closed or partially closed soon afterwards,
and considerably before the main valve closes for "compression," or I may effect
the same object by making the closure take place at the ordinary ports of the
cylinder, either by an alteration in the ordinary ports and valve and valve setting,
or by the addition of a slide or piston or other valve under or over or at the side of
the main valve, or at another part of the cylinder, the result being the same,
namely, to close, at a suitable distance from the cylinder, the communication with
the condenser when the piston has yet the whole or a great part of its return
stroke still to make.
Dated this 2nd day of April 1891
WM. P. THOMPSON & Co.,
Per John Hayes,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Controlling or Regulating the Communication
between a Condenser and a Steam Engine Cylinder during the
Ordinary Period of Eduction, and in Apparatus therefor.
I, THOMAS MUDD, of The Central Marine Engine Works, West Hartlepool,
in the County of Durham, Engineer, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
Numerous facts observed in my experience lead me to look for economy from a
reduction in the time the cylinder of a condensing engine is open to the cold
condenser; and it seems to me that the communication can be stopped at a suitable
point in the passage, without causing a detrimental amount of compression and
without greatly reducing the power produced by a given size of engine.
I propose to effect this object, either by inserting in the exhaust pipe a valve of
the throttle, mushroom, slide, sluice or other type, working the valve by one of the
working parts of the engine in such a way that the passage shall be open when the
main valve of the engine "releases," but closed or partially closed soon afterwards,
and considerably before the main valve closes for "compression," or I may effect
the same object by making the closure take place at the ordinary ports of the
cylinder, the result being to close, at a suitable distance from the cylinder, (so as

page_text: to allow plenty of steam room between) the communication with the condenser
when the piston has the whole or à great part of its return stroke to make, or I
may insert between the cylinder and the condenser a separate vessel or exhaust
receiver, the outlet end of which is fitted with the valve for opening and closing
the communication between this exhaust receiver and the condenser.
Referring to the drawings
:-
Figures 1 and 2 are parts of a marine engine designed by me showing one
application of the machine.
Figure 3 is a diagrammatic view of the invention applied to three-stage compound
engines.
Referring first to Figure 3-
A B and C are three cylinders of a compound engine; D is the condenser,
EEE steam chests; H enlargement of the exhaust pipe or separate vessel, I
call an exhaust receiver, so as to allow of carly closing of valve F without
excessive back pressure.
The distance the valve is away from the cylinder, or, in other words, the
capacity of the space enclosed between the valve and the cylinder, is of importance
and requires to be proportioned in such a way as to be suitable to the size of the
engine and the conditions under which it is run, but suitable distance or capacity
may be varied considerably without greatly affecting the efficiency of this apparatus,
just as the ordinary receivers between the cylinders of a compound engine may be
varied without serious results, and to which receivers the space or receiver now
proposed to be enclosed between the valve and the cylinder is exactly analogous.
The shape also is not unimportant, as it would obviously be less efficient if the
space enclosed were of small cross section and great length, such as a mere pipe,
than if a short length of large cross section were adopted. In many applications,
a separate chest will be most convenient for providing the capacity needed in this
exhaust receiver between the valve and the cylinder, but in some, a portion of the
exhaust passages usually provided will answer the purpose satisfactorily as in the
case shown in the drawing.
The principal object of this enlargement or exhaust receiver is to prevent the last
cylinder from falling to so low a temperature as is usual owing to its being so long
open to the cold condenser.
The intention is that the engine shall so move the valve in the exhaust receiver
as to allow the steam exhausting from the third cylinder free communication to the
condenser for a much more limited time than is usual, the valve in the exhaust
receiver closing again a long time before the exhaust port of the cylinder itself is
closed. Whilst the valve in the exhaust receiver is closed, the exhaust steam from
the cylinder will accumulate in the exhaust receiver, and it is intended that the main
valve of the cylinder shall close on the exhaust side for compression a little before
the valve in the exhaust receiver opens to let away the pressure that has there
accumulated. By this means, the incoming steam into the cylinder will be less
cooled and condensed than is usual, and great economy in the use of the steam will
result.
It is obvious that the exhaust receiver and its valve may be made in many and
various forms. The receiver may either be a separate vessel, or may be part of
the ordinary exhaust pipe, or may be a belt on the cylinder, or otherwise formed.
Its valve may be a common D slide valve, or it may be a grid-iron valve, or it may
be a butterfly valve, or an ordinary stop valve, or equilibrium double-beat valve,
or a clack valve, or other suitable form of valve to suit the particular engine and
situation, its office being in each case the same as described above and applicable
to any steam engine whether horizontal or vertical, whether simple, compound,
triple or otherwise, whether for land or marine purposes.
Figures 1 and 2 show a valve apparatus on this plan designed by me for marine
use, in which the exhaust receiver, not clearly shown in these views, is an enlarged,
but otherwise ordinary exhaust belt on the cylinder.
The valve used in this case is a butterfly valve, and it is moved by the main

page_text: pump levers J. The pump levers J are connected by a connecting rod K to a
quadrant L, and teeth on the face of the quadrant are made to gear in the
pinion M on the butterfly valve shaft N in such a way that the valve P turns half
a circle on the upstroke of the engine and returns again the half circle on the down
stroke of the engine.
In passing, it may be here stated that it is obvious that the valve may be moved
from any moving part of the engine, the part chosen varying with the type of
engine and with the type of valve used, and if such a butterfly valve as that shown
is used, it may either revolve continuously round, or move through part of a circle
and then return.
In Figure 2, it will be observed that the valve works freely past a bored part
at each side of the exhaust passage. When the valve arrives in the position of
either of the dotted lines Q, the passage is closed or nearly so, and, whilst the valve
is passing the bored part and almost touching the same, the passage remains
practically closed. When the edge of the valve goes beyond this bored part, the
passage is open, and, when the valve arrives at its vertical position, as shown, it is
at its maximum opening. This form of valve has been chosen in this case, partly
because it is believed the passage will be sufficiently closed without the valve
actually bearing, and thus no friction will be set up or power expended, except
such as is necessary to overcome the friction in the bearings of the working parts,
the valve itself working clear, and partly because it is a convenient form for a
marine engine.
This valve in the exhaust receiver is open when the engine valve opens for
release, but closes a short time thereafter and remains closed until the main valve
has closed or is about to close for compression.
I have shown this one form of my apparatus suitable for a condensing marine
engine, but the arrangement of valves and exhaust spaces can be varied enormously
without departing from the principle of my invention, and can be applied as
circumstances require to any new or existing engine whether condensing or non-
condensing.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, 1 declare that what I
claim is-
The application of a valve beyond the exhaust from the last cylinder or cylinders
with a suitable distance or space between, so as to allow for a considerable steam
space being interposed between the valve and the cylinder, whereby the valve can
be closed and the escape of steam cut off when the piston has yet the whole or a
large part of its return stroke still to make without causing a detrimental amount
of back pressure.
Dated this 30th day of January 1892
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Nottingham, and London, Patent Agents.