SLIDE VALVE AND GEAR FOR DUPLEX DIRECT ACTING PUMPING ENGINE
Year: 1885

page_text: "
I, JOHN FIELDING, of The Atlas Works, in the City and County of Gloucester,
Engineer, do hereby declare the nature of my invention for "SLIDE VALVE AND
GEAR FOR DUPLEX DIRECT ACTING PUMPING ENGINE" and in what manner the
same is to be performed to be particularly described and ascertained in and by
the following statement:-
Direct acting pumping engines, wherein the steam piston is rigidly connected to
the pump piston, are sometimes mado in duplex form, that is to say, two such
engines are placed side by side, with valves and gear so arranged that the piston of
each cylinder, as it moves to and fro, works the valves for the supply and exhaust
of the other cylinder. My invention relates to engines of this kind and consists in
so arranging and working a single slide valve in connection with a set of ports and
passages, that the movements of this one slide govern the supply and exhaust of
both cylinders. For this purpose, I give the slide valve two movements, the one
movement a reciprocation in one line caused by its connection to the piston of the
one cylinder, the other movement a reciprocation in a line perpendicular to the
former, caused by its connection to the piston of the other cylinder. The movement
given from the piston of each cylinder governs the supply and discharge of the
other cylinder, as I will more fully explain referring to the accompanying
drawings.
Fig. 1 is a side view and Fig. 14 is a plan of the duplex engine shewing
the position of the one valve box for the two cylinders and the connections for
working the valve from the crossheads of the two piston rods. The other figures,
which are drawn to an enlarged scale, are Fig. 2, a longitudinal section of the slide
and gear and Figs. 3 and 4, transverse sections on X X and Y Y respectively. The
crossheads of the two piston rods are linked to levers A and B respectively. The
short arm of A, which is worked from the piston of the cylinder 1, is linked to
a sleeve C fitted between collars on the slide rod D which is fitted with a feather
to slide through another sleeve E. The sleeve E has on it a toothed bevil segment
gearing with a segment on B which is worked from the piston of the cylinder k.
Both the levers A and B are mounted on trunnions of a stationary bracket F
within which the sleeve is free to turn. Thus the lever A moved by the one
piston, that of the cylinder gives to the slide rod D a to and fro reciprocating
[Price Ad7

page_text: movement, and the lever B moved by the other piston, that of the cylinder / by
means of the bevil gear gives the slide rod D a partial rotation to and fro on
its own axis. The slide G has a face which is a segment of a cylinder with a
central cavity fitting to a cylindrical casing, in which there are formed five ports, a
central port H for exhaust, two end ports K K leading to the two ends of the
cylinder and two side ports L L leading to the two ends of the cylinder 1.
The slide G, as it is moved to and fro longitudinally by the piston of the one
cylinder over the ports K K governs the supply and exhaust of the other
cylinder and the same slide G as it is rocked to and fro transversely by the
piston of the cylinder k over the ports L L governs the supply and exhaust of the
other cylinder L.
Although I have shewn the slide and facing of cylindrical form, they might be
flat, the slide receiving its transverse movement from an arm on the rocking slide
rod. The slide might be placed and moved diagonally, the four ports K K and LL
being arranged in diamond form; parallel respectively to the four sides of the slide.
The opening and closing of the ports being then effected by the movements of the
slide compounded of its longitudinal and transverse motions, would recur in an
order corresponding nearly to movements of the two pistons such as they would
have if they were connected to cranks at right angles to one another. Other forms
might be given to the slide, the four ports around the central exhaust port being
arranged and situated to suit the shape and the two motions of the slide.
Having now particularly described and ascertained the nature of my said
invention aud in what manner the same is to be performed, I declare that what
I claim is
"
For a dúplex direct acting pumping engine, the construction and arrangement of
a single slide, moved longitudinally and transversely by gear connecting it to the
two pistons, so as to govern four ports two for each of the two cylinders arranged
around a central exhaust port, substantially as herein described,
Dated this 2nd day of April 1885.
ABEL & IMRAY;
Agents for the Applicant,
28, Southampton Buildings,
London, W.C.