Improvements in Compounding Fluid Pressure Motive Power Engines.
Year: 1896

page_text: Date of Application, 15th May, 1896
Complete Specification Left. 10th Nov. 1896-Accepted 15th May
1807
PROVISIONAL SPECIFICATION.
Improvements in Compounding Fluid Pressure Motive Power
Engines.
I RICHARD ERNEST BRADFORD of 5 Meath Street Battersea Park
Road S. W. Marine Engineer do hereby declare the nature of this invention to
be as follows:-
It relates to improvements in the timeing of valves of all existing types of
compound multiple-expansion engines, either of two or three cranks, or their
substitute, so as to have the atmosphere, or in condensing engines, the condenser,
for the back-pressure line, of an indicator diagram, of each, of any number of
cylinders, expanding successively into each other.
As relates to two cranks at right angles :-I effect my improvement, by admitting
steam to the high-press cylinder, to the ordinary extent, but the exit opens before
half stroke, at the time of admission, for the low-press, whose crank is now on the
top-centre. The high & low thus do half a stroke in company, the steam expanding
simultaneously in both cylinders.
The next eighth of the revolution, commences to bring the high pressure back,
but against a pressure equivalent to the capacity of H.P. +L.P., but the back-
ward movement of the high-press is very small in comparison to the forward
movement of the low-press.
And here the exhaust to the condenser opens, the steam being expanded
ths H.P. +3ths L.P. The exit from H.P. & the admission to L.P., still remain
open until the H.P. gets again to the top of its stroke.
So that the H.P. returns ths of its stroke against the L.P. exhaust or condenser
pressure. So that in compound engines the proportion of whose cylinders'
capacity is 1:3, the steam expands of (1+3)=3 times the capacity of
the H.P. and both pistons return against the atmosphere or condenser pressure.
This just about doubles the output of work, from the given quantity of steam
supplied to this engine, & more than doubles the power capacity of the engine.
Now as relates to three-crank engines :-
The high-pressure exit opens at 120° to admission for intermediate; the inter-
mediate & high press proceeding in company for 60°, and during the next 60° the
high-press only returns stroke, when the low-press admission opens, there now
being a clear way thro' from the high-press to the low-press.
The steam now occupies the high-press plus the whole intermediate; and the
low press has commenced its stroke. The intermediate & low-press go out in
company on the same steam during another 60°-the bigh-press is now rds way
back; the intermediate at the bottom & the L.P. 60° out. The pressure being
equivalent to 1.P. +L.P.
The next 60° brings the H.P. to the top. The intermediate has only moved
back & the low-press is ths dowu.
In engines with cylinders as 4:9: 25 areas, the steam pressure is equivalent
9+ 25
to of
4
the capacity of H.P. cyl. or equal 6 about.
And if the cut-off is about half-stroke of H.P. this means the return line on
the H.P. diagram, drops to below th the initial pressure.

page_text: Suppose the initial pressure 150 lbs., the back-pressure drops to 12 lbs. instead
of, by the usual setting abt. 60 to 65 lbs. that is to say, it drops to about th of
the present practise.
During the next 40 odd degrees, the I.P. has returned to position rd back &
the exhaust has opened to the L. P. at a pressure equivalent to 3rds I.P. +
L.P.
6 + 25
4
abt. 8 times capacity of high-press cylinder.
Now the I.P. returns against atmosphere or condenser as the case may be so
that rds the intermediate as well as the whole low-press return against the
condenser pressure, only: & the H.P. against 12 expansions.
This more than doubles the output of work from a given quantity of steam in a
three-crank engine. Thus the triple-expansion engine, of the ordinary marine
type, developes, working single-acting, & using only half the quantity of steam,
more than its original power working double acting.
Working double-acting to this invention it developes more than twice its original
power, on the same steam supply.
There is an alternative arrangement :-To which this invention relates, in regard
to the opening, by a seperate valve, the contents of the H.P. to the atmosphere
(or the condenser) & in case of a three-crank engine, arranged single-acting, each
underside of cylinder, may be permanently connected with the condenser.
Or they may be fitted with a transfer-valve simular to Watts pumping engines &
in this case the full capacity of the three cylinders, is availed of for a single-acting
4+9+25
4
engine; the expansive capacity of this engine thus becoming
= 9 times
the capacity of the H.P. cylinder. And the diagrams from each of the three
cylinders, have the condenser for the back-pressure line.
Thus making a three-crank quadruple, working single-acting on half the steam
consumption, approximately its original output.
A slight addition or alteration will avail all types of compound engine, of the
advantages of my invention, as the circumstances of each particular make may
require.
And in some cases a re-arrangement of the main-movement or any other part
of the engine may be couvenient or advantageous to this end.
In some cases the advantage gained in the higher-pressure cylinders may be
proportioned to that gained in the low-pressure, and the balance of the engine
will not be prejudicially affected; but in others, special arrangements will be
necessary, and in some cases it will effect economy to design the entire engine to
this invention.
In ordinary types of high-luty engine, the receiver or back-pressure rises
slightly, due to the diminishing space, by return of piston in exhausting cylinder,
by a line which may be described as a form of cushioning line, and in slow-running
engines, this may be slightly increased, by receipt of aditional heat from jackets
of receiver & cylinder. And there is a type of engine, working differentially to
avoid dead centering; and there is the Woolf's engine which avoids the requisition
of the receiver; but each of these types is capable of improvement, either in a
partial manner, or to the full extent of the theoretic value, of the steam,
(considering the "theoretic value" of the steam to mean, that which may be saved,
in spite of the insipient loss thro' cooling, clearance & valve passages); and this
invention relates to all advances in this direction, & for the purposes herein set
forth & for the first time discribed & laid down in compound or multi-cylinder
engines, working exhaustively the one into the other, either with or without other
chambers.
Dated this 14th day of Mav A.D. 1896.
RICHD. E. BRADFORD.

page_text: Improvements in Compounding Fluid Pressure Motive Power
Engines.
I RICHD. ERNEST BRADFORD 52 Gracechurch Street London E.C. Engineer
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:-
My invention consists in avoiding the back-pressure in compounding by allowing
the steam to expand to the full capacity of all the cylinders employed. No receiver
is necessary between the cylinders, the cooling period is shortened and there
is only one half the time of exposure to leakage in the cycle and fewer parts are
necessary.
The drawings shew the simplest form of this invention as applied to an engine
with pistons tandem and each cylinder single-acting the result being th more
work and th more economy of steam per horse power than any other compound
engine of the same cylinder capacity.
The cause for this result will be readily ascertained by reference to Fig. 8.
and the accompanying valve diagrams Figs. 7, 9 and 10 whose parts are moving in
the direction indicated by the respective arrows:-a is the steam supply, b the
admission to the high-pressure-cylinder, c is the intermediate port and d the
exhaust, e being a thro' passage.
The cycle commences with Fig. 7, the crank is on the top or back-end, steam
admission is opening to work side of high-pressure piston, and the other side
of high-pressure piston and both sides of low-pressure piston are opening to
exhaust.
In Fig. 8. the engine is at half-stroke the steam admission port b is just closed
and all the rest of the engine is full open to exhaust. The low-pressure piston is thus
in equilibrio.
In diagram Fig. 9. the engine is at full stroke, the port b is now open to act as
an intermediate passage, the intermediate port e being in the act of opening and the
passage e always remains open. There is thus communication between both sides
of the high-pressure piston and the crank-side of the low-pressure piston. The
high-pressure piston is thus in equilibrio.
b
In diagram Fig. 10, the engine is shown half-stroke back, the port 6 has closed,
the intermediate port c is however open to its full extent.
It is thus obvious 1st that both pistons are in equilibrio respectively during their
return stroke, 2nd all back-pressure is avoided, 3rd the steam expands to the
capacity of the high-pressure cylinder plus the capacity of the low-pressure
cylinder, 4th the steam cut-off being one half and the cylinders being as one to four
the expansion equals ten or two more expansions than in any other compound
engine.
The details of this engine will be readily understood by ref. to Fig. 8:-There
are two arms on the eccentric strap, one of the valve-rods having a guide the other
derives a parallel motion and a later period of action; the first valve opens rapidly
for admission to both cylinders and the second valve closes suddenly for
cushioning to both cylinders, thus doing the work of the ordinary expansion-gear
combination.
THE ESSENTIAL CONDITION.
This invention may be used in any engine provided there is thro' communication
from No. 1 cylinder to No. 2 cylinder until the exhaust is opened.
And of course there are many ways in which this may be effected as convenience
may suggest in any particular engine, thus:-1st by the timing of the periodic

page_text: movement of the valve 2nd by the periodic movement of the engine itself, by discs,
cams, sheaves or screw surfaces, rollers, levers &c., 3rd by combining the periodic
movements of the engine and of the valve-gear-and these may all, for the
convenience of this description, be referred to merely as substitutes for the crank
and eccentric movement, so that it will be only necessary for me to describe the
application of my invention to engines of two and three cranks with ordinary
eccentric movement, the ports in the valves and their seatings being modified to
suite the conditions of the diagrams Figs. 1 to 6.
In diagrams Figs. 1 to 6-a represents the port leading from the steam-chest into
the top or front end of the high-pressure cylinder and the port into the top or front
end of the low-pressure cylinder; c is the port leading from the steam chest into
the botton or rear or crank-end of the high-pressure cylinder and d is the port
ileading into the bottom, rear or crank-end of the low-pressure cylinder.
The valve is provided with two chambers or cavities and g.
Fig. 1. shows the valve on the point of admitting live steam to the front end of
the high-pressure cylinder.
Fig. 2. shows the valve moved so as to half uncover the port a.
Fig. 3. shows the port a fully open.
Fig. 4. shows the valve at the point of admitting live steam to the rear of the
bigh-pressure piston.
Fig. 5 shows the port d half open.
Fig. 6 shows the port d fully open.
And in order that the practical utility of these diagrams Figs. 1 to 6 may be
understood I will follow thro' the results of the application of my invention in the
case of a two-crank compound engine, of a three-crank triple-expansion engine and
of a one-crank compound engine :-
Two CRANKS AT RIGHT-ANGLES.
In applying my invention to engines having two cranks at right-angles to each
other, and in order to gain part of the advantage of my invention, I admit steam to
the high-pressure cylinder, to the ordinary extent, but the exit opens just after
half-stroke, at the time of admission for the low pressure cylinder whose crank is
now on the top centre.
The high and low-pressure pistons thus make half a stroke in company, the steam
expanding simultaneously in both cylinders.
The next eighth of the revolution, commences to bring the high-pressure piston
back, but against a pressure equivalent to the capacity of the bigh-pressure + low-
pressure, but the backward movement of the high-pressure is very small in
comparison to the forward movement of the low-pressure. And here the exhaust
to the low-pressure opens the steam being expanded ths high-pressure plus ths low-
pressure. The exit from high-pressure cylinder and the admission to low pressure
cylinder still remain open until the high-pressure piston gets again to the top of
its stroke so that the high-pressure piston returns ths of its stroke against the low
pressure exhaust or condenser pressure. In compound engines with a proportion
of one to three cylinder capacities, the steam expands ths of (1+3)=3 times
the capacity of the high pressure cylinder and both pistons return against the
atmosphere or condenser pressure.
CRANKS AT 120°.
In applying my invention to engines having three cranks, and in order to gain
part of the advantage of my invention, the high-pressure exit opens at 120° to
admission for intermediate; the intermediate and high-pressure pistons proceeding
in company for 60°, and during the next 60° the high-pressure only returns
stroke, when the low-pressure ordinary admission valve opens, there now being a
clear way from the high pressure thro' the intermediate to the low-pressure
cylinder. The steam now occupies the high-pressure plus intermediate; and

page_text: ressure
pistons go out in company on the same steam during another 60° and the high-
pressure piston is now rds way back; the intermediate at the bottom and the
low-pressure 60° out. The pressure being equivalent to intermediate cylinder
capacity low-pressure capacity. The next 60° brings the high pressure piston
to the top. The intermediate piston has only moved back and the low-pressure.
piston is ths down.
In engines with cylinders as 4: 9: 25 areas, the steam pressure is equivalent
9 + 25
to of
the capacity of high-pressure cylinder, or equal 6 about, an if
the cut off is about half stroke of high-pressure this means the return line on the
high pressure diagram, drops to below th the initial pressure.
4
Suppose the initial pressure 150 lbs., the back-pressure drops to 12 lbs., instead
of, by the usual setting about 60 to 65 lbs. :-that is to say it is only about th of
the obstruction resisted hitherto, ths having by this improved compounding, been
entirely removed.
DOUBLE ACTING.
Two crank and three crank engines may be used either single or double-acting
by this arrangement, no receiver being required and in consequence of the long
period of intermediate communication, passages much less than the ordinary size
are sufficient.
The method I shall generally employ in single-acting engines may be the more
fully understood by referring again to the drawings Figs. 1 to 6 only now using
half the diagrams, say ports a and b and cavity f; but permanently connecting
port b both with the front or working end of the intermediate cylinder and with
the rear or crank end of the high-pressure cylinder. The result of this is:-at the
point of lead of the intermediate pressure the high-pressure-piston is in equilibrio
and remains so until exhaust from the low-pressure, and in this case the full capacity
of the three cylinders is available for a single-acting engine, the expansive capacity
of this engine will then be
= 9 times the capacity of the high-
4 +9 +25
4
pressure cylinder. And the diagrams from each of the three cylinders, have the
condenser pressure for the back-pressure-line no receiver being required.
In applying my invention to single-acting compound engines having one crank
the high and low-pressure pistons being connected together, and in applying my
invention to single-acting compound engines having two cranks, the cranks being
opposite, the high-pressure valve arrangement is the same as my general
arrangement for single-acting engines just described in the previous example, and
in all these instances the advantage gained in the higher-pressure cylinders may be
proportional to that gained in the low pressure without altering the balance of the
engine.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
Timing the opening and closing of the valves to the cycle of the crank or cranks,
with or without equilibrium-valve, receiver or seperate chambers, for half-part or
usual cooling period; so as partially or entirely to reduce the back-pressure on all
the pistons to that on the low-pressure piston by means of thro' communication
until the exhaust is opened.
Dated this First day of May 1807
RICHD. E. BRADFORD.