Year: 1885

page_text: I, EDWARD FIELD, of Chandos Chambers, Adelphi, in the County of Middlesex,
Consulting Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention has reference to engines of the kind described in the specification
of Letters Patent N° 2474 dated 15 July 1874 granted to me and another.
In the said specification no provision was made for circumferential wear of the
distributing valves. Now according to my present invention, the arrangement of
the valves and passages is much simplified and the piston valves after passing the
ports seat themselves in conical seats (steam tight) thus preventing leakage.
Touching pieces are provided so that if from any cause the valves should become
too stiff to be moved by the differential steam pressures as intended, these touching
pieces will come in contact with the covers of the cylinder and so overcome the
obstruction. The action of the steam on the valves is such, that the touching
pieces do not come in contact with the covers of the cylinder unless there is
occasion for their so doing. When this arrangement of compound cylinders is
intended to be used to provide rotary motion I simply connect the main piston rod
by means of a connecting rod to a crank shaft in the ordinary manner, and dispense
with the use of an eccentric and usual gear connected there with thus producing an
efficient, economical, compound engine at low cost. When a pump is to be driven
the main piston rod may be rigidly connected with the pump rod and an efficient,
economical steam pump is produced.

page_text: I, EDWARD FIELD, of Chandos Chambers, Adelphi, in the County of Middlesex,
Consulting 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:-
This invention has reference to engines of the kind described in the specification
of Letters Patent N° 2474 dated 15 July 1874 granted to me and another.
In the said specification no provision was made for circumferential wear of the
distributing valves. Now according to my present invention the arrangement of
the valves and passages is much simplified and the piston valves after passing the
ports seat themselves in conical seats (steam tight) thus preventing leakage.
Touching pieces projecting either from the valves or cylinder covers, are provided
so that if from any cause the valves should become too stiff to be moved by the
differential steam pressures as intended, these touching pieces will actuate the
valves and so overcome the obstruction. The action of the steam on the valves is
such, that the touching pieces do not come into action unless there is occasion for
their so doing. When this arrangement of compound cylinders is intended to be
used to provide rotary motion I simply connect the main piston rod by means of
a connecting rod to a crank shaft in the ordinary manner, and dispense with the
use of an eccentric and usual gear connected therewith thus producing an efficient,
economical compound engine at low cost. When a pump is to be driven the main
piston rod may be rigidly connected with the pump rod and an efficient, economical
steam pump is produced.
I
Referring to the accompanying drawing which is a longitudinal section of high
and low pressure cylinders, with distributing valves and attached parts according
to my invention. a is the high pressure piston fixed by its rod to the back end
cover of the low pressure cylinder c. a is the high-pressure cylinder which with
its flanges b. b forms the low pressure piston and is of a reel or bobbin form; the
space between the two flanges is a little longer than the stroke of the engine and
it follows that a central port c¹ in the low pressure cylinder c and which is in com-
munication with the steam supply, will always be open to the space, or travelling
steam jacket d round the high pressure cylinder, a¹. e.e¹ are the cylindrical conical-
faced distributing valves. f. f' are corresponding conical seats for the said valves.
g. glare the passages from the steam jacket d to the cylindrical valve chest h. k. I¹ are
ports from h into the cylinder a¹. are the exhaust ports of the low pressure
cylinder c. m is a cylindrical valve chest. n. n¹ are piston valves; o the central
exhaust port; p the valve rod, and q. q. cushion springs. . are passages which
are opened to the steam jacket d at the end of each stroke by the flanges b; each
of these ports 7. 71 communicates at one end with the valve chest m. 8. 8 are
grooved passages which allow a small quantity of steam to pass from the steam
jacket d to one end of the low pressure cylinder c at the end of each stroke.
ttare studs or touching pieces projecting into the cylinder c to such an extent
that should the valves e. e¹ not be moved by the action of the steam, they will be
moved by coming in contact with the ends of the studs.

page_text: The operation of the engine is as follows: Steam being admitted into the
travelling steam jacket d through the port c¹ the low pressure (or main) piston
being at the back end of the cylinder as shewn and the distributing valves e. e¹ in
such a position that the valve e' is in its seat f, then steam will pass from the
jacket & through the ports g. gl into the valve chest hand thence through the
port into the right end of the cylinder a¹. The piston a being fixed the steam
will drive the cylinder a' to the right hand at the same time the steam which has
done high pressure duty in a¹ will escape through k and expand into the low
pressure cylinder c urging the main piston in the same direction: the low pressure
exhaust steam will escape through the port the valves n n¹ being previously
forced over to the right by steam passing through the passager from d. The same
action takes place on the return stroke. The valves are entirely self acting and
the piston rod being connected to the crank in the usual way no eccentric or valve
gear is required. The distributing valves e e¹ are actuated by steam from d passing
through the port 8 or 8¹ at each end of the stroke and acting on the outer end of
the valve e or e¹ as the case may be.
Having now particularly described and ascertained the nature of my inven-
tion and in what manner the same is to be performed, I declare that what
I claim is:-
1. Adapting a compound engine of the kind described in the specification Nº 2474.
AD 1874 to work without valve gear external to the cylinders.
2. In a compound engine of the kind referred to the hereinabove described
arrangement of steam moved distributing valves and of seatings according to which
each valve at the termination of its stroke seats itself in its seating as explained
with reference to the drawing.