Improvements in Engines in which Steam and other Expansive Fluids are the Motive Power.
Year: 1890

page_text: COMPLETE SPECIFICATION.
Improvements in Engines in which Steam and other Expansive
Fluids are the Motive Power.
We THOMAS SUMMERTON Junr. of the City of Christchurch in the Colony of New
Zealand, Engineer, and JOHN BROWN of Mangere, Onehunga, in the Colony of New
Zealand, 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 :-
Our invention relates to improvements in engines in which steam and expansive
fluids are the motive power, and has for its objects making an engine in which a
high pressure and great expansion can be utilised with economy by simple machinery,
occupying a smaller relative space than the usual compound engines, and the piston
rod gland being exposed to low pressure steam.
In order that our invention may be most easily understood, we will now proceed to
describe the same and for that purpose shall refer to the accompanying sheet of
drawings on which similar letters indicate corresponding parts in all the figures.
Fig. 1 is a vertical section of the cylinder, and slide valves of our improved engine
as designed for triple expansion with one cylinder and piston rod.
Fig. 2 is a vertical section of the same as designed for five expansions with two
cylinders and two piston rods.
Fig. 3 is a section through the line A. B.
Fig. 4 is a skeleton view shewing compartments arranged for quadruple expansion
in one cylinder.
a. a. (Fig. 1) is the cylinder having for about one half its length at one end a
projecting portion (b. 6) which serves to reduce its internal diameter, and which
projection can be either solid or formed into a steam receiver or steam jacket.
c. c. is the cover or upper part of the cylinder made of smaller diameter than the
cylinder (a. a.).
P p p are pistons fitting respectively into the cylinder or cover (c), the main
body or cylinder (a. a.), and the contracted portion of the cylinder (a¹) as shewn.
These pistons are all firmly joined together, and held firmly at their respective
distances by trunks or piston rod cylinders.
d is the piston rod common to all the pistons, and attached in the usual manner to
the crank shaft or work to be performed.
9. 9' 9' 9' are pistons of another form of our improved engine as shewn in
(Fig. 2).
It will been by this arrangement of the cylinder and pistons, that the cylinder and
its cylindrical cover are divided into chambers (Nos. 1. 2. 3 and 4) into all of which
the steam is admitted at different grades of expansion.
e. is a slide valve for chamber (4) Fig. 1.
f. is a slide valve for chambers (1 and 2).
g. is a slide valve for chamber (3).
The valves (e and f) are so designed and arranged that whilst high pressure
steam is being introduced into (No. 1) from the boiler by the valve (f) as shewn in
(Fig. 1), expanded steam is being withdrawn from (No. 2) to do further work in
(No. 3), both pressures acting in an upward direction at the same time as shewn by
the arrows (el and f').
But on the return stroke of the piston the steam from (No. 1) is expanded into
(No. 2) as shewn by the valve (f) Fig. 1 a, and at the same time the steam from
(No. 3) can (if desired) be exhausted into a vacuum as shewn by the slide valve (g)
Fig. 1a.
We thus obtain in the same cylinder and cover with one piston rod and valve rod
gear. triple expansion and a vacuum.

page_text: The compartment (No. 4) can also be supplied with a small amount of steam from
the boiler, or from a receiver supplied by (No. 2) compartment on the downward
stroke (see e. Fig. 1. a), and be afterwards condensed to produce a vacuum on the
upstroke (see Fig. 1).
It will thus be seen that the three valve chests (are by preference in one straight
line, and have one valve rod for the three valves, which are therefore all actuated at
once and in the same direction.
The valve (f) is so designed that its steam chest being supplied with steam
direct from the boiler is admitted into (No. 1) compartment, and exhausted into
(No. 2).
The valve (g) is arranged so that its chest receiving the steam from (No. 2),
admits it to (No. 3), and finally exhausts it to the atmosphere or the condenser.
This engine can be doubled so as to give six expansions, or in extraordinary cases
of high pressure, three or more cylinders might be used.
In (Fig. 2) is shewn a double cylinder engine in which the lower piston (p³), and
compartment (No. 3) of (Fig. 1) and their slide valve are dispensed with.
In this engine high pressure steam from the boiler entera (No. 1) compartment
pressing the piston (q) downwards, and on the return stroke the steam from (No. 1)
enters (No. 2) pressing the piston (g) upwards, it then expands into (No. 3)
pressing (7) downwards, and then into (No. 4) pressing (7) upwards.
The steam from (No. 4) can expand into (No. 5) or (5 a) alternately, slightly
pressing down the trunk piston, and on their return stroke forming a vacuum by the
condenser on the pistons (9³ and q³).
If deemed necessary the compartment (5 a) can be left open to the atmosphere,
which will give greater simplicity of construction.
By the double cylinder engine we provide five expansions, and a vacuum in two
cylinders.
The method of moving and action of the slide valve need not be further explained,
being driven by ordinary eccentric or other suitable gear, the action of which is
well known to competent engineers.
We wish it to be understood that we do not confine ourselves to the exact
mechanical details, for it is evident (Fig. 2) one engine may be made use of{without
the pair, also that valves of other construction may be used to actuate our improved
cylinders, and pistons instead of our slide valves. Also that ordinary engines may
be attached to our improved cylinders to make a compound engine, and the several
details may be varied without departing from the principle of our invention, but,
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is :-
1st. The arrangement of cylinder and its compartments with the several pistons
substantially as described herein and illustrated in (Fig. 1).
2nd. The construction of the slide valves in combination with the cylinder and
pistons, substantially as described herein and illustrated in (Fig. 1).
3rd. The arrangement of cylinder and the compartments of the same, substantially
as described herein and illustrated in (Fig. 2).
4th. The construction of the slide valves combined with the cylinders and pistons,
substantially as described herein and illustrated in (Fig. 2).
5th. The arrangement of two, three, or more combined cylinders with valves
and valve gearing, substantially as described herein and illustrated in the accompanying
drawings.
6th. The combination of our improved cylinders and valves to work in conjunction
with the cylinders of ordinary steam engines.
E. EDWARDS,
35, Southampton Buildings, London, Agent for the Applicants.