Improvements in Duplex Pumping Engines.
Year: 1891

page_text: Date of Application, 4th Sept., 1891
Complete Specification Left, 7th June, 1892-Accepted, 16th July, 1892
PROVISIONAL SPECIFICATION.
Improvements in Duplex Pumping Engines.
I, JAMES PATTERSON, of West Lodge, Walker, in the County of Northumber-
land, Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to pumping engines of the kind commonly known as
duplex direct acting pumps (in which the motion of the valve of either pump is
controlled by the motion of the piston of the other pump) and has reference to
the valves and valve gear of the motive power cylinders.
According to this invention a pumping engine of this description is so con-
structed that the motive fluid distributing valve of each motive power cylinder is
operated in part from a moving portion of each of the two pumps.
For the purposes of explanation I will assume steam to be the motive fluid and
the steam distributing valves to be slide valves, and call the pumps No. 1 pump
and No. 2 pump respectively. Under these assumed conditions the slide valve of
No. 1 pump derives part of its motion from No. 1 pump and part from No. 2
pump; and the slide valve of the No. 2 pump will be similarly operated.
According to one arrangement each slide valve is operated by an eccentric_and
the two eccentrics are fixed to the same shaft. This shaft is rotated through about
one fourth of a revolution at each stroke of each pump so that in one double stroke
of both pumps it completes a revolution.
This arrangement is illustrated by way of example in the accompanying
drawings.
Fig. 1 is a longitudinal elevation with the steam cylinder of No. 1 pump in
section.
Fig. 2 is a cross section.
Fig. 3 is a plan with the steam chest covers removed: it shows the valve for
No. 2 pump in mid position and that for No. 1 pump full open.
Figs. 4, 5, 6 and 7 show the valves, valve gear, and ports more in detail.
A is No. 1 pump and B No. 2 pump.
P1 and P2 are the piston rods to which are attached arms C1 and C2 for operating
levers D' and D2 on the valve shaft. S is the valve shaft having the levers Di
and D2 one at each end of it. E and E² are eccentrics also keyed on to the valve
shaft S. F and F are the eccentric straps to drive the valves V¹ and V2.
Fig. 4 is an enlarged sectional elevation of the No. 2 pump valve V2 showing
the relative positions of the levers &c. for operating it, the dotted arm C¹ and
lever D¹ being those of No. 1 pump.
Fig. 5 is a plan corresponding to the elevation Fig. 4.
Figs. 6 and 7 are similar views to 4 and 5 showing the valves in a different
position.
The action of the gear will be best understood by following it through half a
revolution of the valve shaft. Supposing the piston of No. 2 cylinder to be at
the end of its stroke furthest from the pump, that is to say at the left end of its
stroke, and the distributing valve V2 for that cylinder to be in the position shown
in Fig. 4. The valve V2 is being moved from left to right by the eccentric E³,
valve shaft S, lever D', arm C' and piston rod P¹ which is moving from right to
left. The arm C2 is stationary but commences to move as soon as the valve V'
admits steam to the left hand end of the cylinder H2; this occurs before steam is
cut off from the cylinder H' so that one or other cylinder is always open to steam
and there is no position in which the pumps will not start on steam being admitted.
The arm C now operates the lever D' for about one fourth of a revolution bringing
the valve V2 to the same position as before but moving in the opposite direction;

page_text: this position is shown in Figs. 6 and 7 with the relative position of the other
valve V and the gear. Fig. 7 shows that steam is now admitted to the left end
of cylinder H¹ so that the arm C' commences to operate the valve shaft through
the lever D and continues to operate the shaft till it gives lead to the right end
of cylinder H².
The second half revolution is exactly like the first half but from opposite ends of
the cylinders.
Four small ports or by-passes L M N O are cut in the valve faces and two
recesses in each valve W₁, W2 X1, X2 and two holes Y and Z in the flange of the
valve V2.
The ports serve to admit a small quantity of steam to each cylinder when the
piston is nearing the end of its stroke, and after the main port is shut off, and so
enable the piston to complete the stroke with certainty. Thus for the position of
valves shewn in Figs. 6 and 7 the piston of No. 2 pump is approaching the right
end of its stroke and the main port is just closed to steam but the small port L and
recess W2 still admit steam. These small ports are further so arranged that
they do not give lead to the valve, that is to say, steam it not admitted by them
before it is admitted by the main port. This is shown in Figs. 4 and 5 where the
valve V2 is about to admit steam to the left end of the cylinder of No. 2 pump,
but no steam can get in through the small port L because it is covered by the
valve V1.
Dated this 4th day of September 1891.
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.Č., Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Duplex Pumping Engines.
I, JAMES PATTERSON, of West Lodge, Walker, in the County of
Northumberland, 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 relates to pumping engines of the kind commonly known as
duplex direct acting pumps, in which the motion of the valve of each pump is
controlled by the motion of the piston of the other pump, and it has reference to
the valves and valve gear of the motive power cylinders of such pumps.
According to this invention a pumping engine of the kind referred to is so
constructed that the motive fluid distributing valve of each motive power cylinder
is operated in part from a moving portion of each of the two pumps.
For the purpose of explanation I will assume steam to be the motive fluid and
the steam distributing valves to be slide valves, and call the pumps No. 1 pump
and No. 2 pump respectively. Under these assumed conditions, the slide valve of
No. 1 pump will according to this invention derive part of its motion from No. 1
pump and part from No. pump and the slide valve of the No. 2 pump will be
similarly operated.
According to one arrangement each slide valve is operated by an eccentric and
the two eccentrics are fixed to the same shaft. This shaft is rotated through about
one fourth of a revolution at each stroke of each pump so that in one double stroke
of both pumps it completes a revolution.
An arrangement for this purpose is illustrated by way of example in the drawings
left with my Provisional Specification in which,
Fig. 1 is a longitudinal elevation of a duplex engine constructed according to
this invention, the steam cylinder of No. 1 pump being in vertical section.
Fig. 2 is a cross section."

page_text: Fig. 3 is a plan with the steam chest covers of the two motive power cylinders
removed; it shows the valve for No. 2 pump in mid position, and that for No. 1
pump full open.
Figs. 4, 5, 6 and 7 show the valves, valve gear, and ports more in detail.
A is No. 1 pump and B No. 2 pump. P¹ and P2 are the piston rods to which,
are attached arms C¹ and C' respectively for operating the levers D' and D² fixed
one at each end of a valve-operating shaft S. E' and E' are eccentrics also keyed
on to the valve shaft S. F¹ and F2 are the eccentric straps to drive the motive
fluid distributing valves V and V2 respectively.
Fig. 4 is an enlarged sectional elevation of the No. 2 pump valve V2, showing
the relative positions of the levers and other parts for operating it, the dotted.
arm C and lever D¹ being those of No. 1 pump.
Fig. 5 is a plan corresponding to the elevation Fig. 4.
Figs. 6 and 7 are similar views to 4 and 5 showing the valves in a different
position.
The action of the valve gear will be best understood by following it through half
a revolution of the valve operating shaft. Supposing the piston of No. 2 motive
power cylinder to be at the end of its stroke furthest from the pump-cylinder, that
is to say at the left hand end of its stroke, and the distributing valve V for that
motive power cylinder to be in the position shown in Fig. 4, then the valve V2 will
be moving from left to right by the action of the eccentric E, valve shaft S,.
lever D¹, arm C' and the piston rod P¹ which will be then moving from right to
left. The arm C2 will be stationary at first, but will commence to move as soon
as the valve V2 admits steam to the left hand end of the motive power cylinder H2;.
this will occur before steam is cut off from the other motive power cylinder H' so
that one or other cylinder will be always open to steam, and there will be no.
position in which the pumps will not start on steam being admitted. The arm C²
will now operate the lever D2 for about one fourth of a revolution, thereby
bringing the valve V2 to the same position as before but moving in the opposite
direction; this position is shown in Figs. 6 and 7 with the relative position of the
other valve V and the operating gear therefor. Fig. 7 shows that steam is now
being admitted to the left end of the motive power cylinder H' so that the arm C¹
will commence to operate the valve shaft through the lever D and will continue
to do so until the valve V2 uncovers the port leading to the right end of
cylinder H2.
The second half revolution is exactly like the first half, but from opposite ends
of the cylinders.
L L'are ports cut in the plate forming the valve face upon which the two
valves V1 V2 work, and which ports communicate with a by-pass cut in the under-
side of this plate as indicated by dotted lines. M M, N N', and OO₁ are similar
ports to L L communicating with other by-passes, indicated by dotted lines.
formed in the underside of the said plate. Wi and X' are two recesses formed in
the underside of the valve V₁, and W2 and X2 are similar recesses formed in the
underside of the valve V2 Y and Z are two holes formed through the flange of
the valve V2, one, (Y) being arranged to come over one of the ports M, and the
other (Z) to come over one of the ports N, during the travel of the valve V2.
These ports and by-passes serve to admit a small quantity of steam to each end
of each cylinder when the piston of such cylinder is nearing the end of its stroke,
and after the corresponding main port has been shut off, and so enables the piston
to complete its stroke with certainty. Thus in Figs. 6 and 7 the piston K² is
approaching the right end of its stroke and the left hand main port is just closed
to steam, but the small steam port 1, which as will be seen is at this time
uncovered by the valve V, will still admit a small quantity of steam to such main
port by way of the corresponding by-pass, and the recess W2 in the valve V
which recess is sufficiently large to cover the second port L and part of the main
steam port. This admission of steam will continue until the recess W2 moves from
above the port L, which will bappen at the same time as the release or exhaust

page_text: takes place from the left hand end of the cylinder. By thus admitting this small
amount of steam, the piston will be caused to complete its stroke to the right and
to come to rest slowly. The other ports, by-passes, and recesses, with the
holes, act in a similar manner, as will be readily understood, for admitting a
small quantity of steam to each of the other main ports in turn for the purpose
mentioned. As will be seen these small ports are so arranged that they do not
give lead to the valve, that is to say, steam will not be admitted by them before it is
admitted by the main port. This will be seen by reference to Figs. 4 and 5 where
the valve V2 which is now moving to the right, is about to admit steam to the left
end of cylinder H2, but no steam can get in through the small port L' because it is
covered by the valve V¹.
Thus it will be understood that by my invention the strokes of each pump will
always be completed as the cut off, compression and release are all effected by
the pump itself the piston of which must be at the end of its stroke before these
operations can take place, the lead and admission being effected by the other
pump, consequently short strokes, such as are sometimes made in duplex engines
as ordinarily constructed, cannot be made in duplex pumps constructed as
described.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that
what I claim is:-
:
1. Duplex pumping engines in which each motive fluid distributing valve is
operated partly from the piston of the cylinder to which it distributes motive fluid
and partly from the piston of the other cylinder substantially as hereinbefore
described.
2. Duplex pumping engines of the kind referred to in the preceding claim,
constructed with valve operating mechanism arranged and operating substantially
as described and shown.
3. Duplex pumping engines having the valve face upon which the two steam
distributing valves work, constructed with steam ports in communication with
by-passes, and the steam distributing valves with recesses, and the flange of one of
these valves with two holes Y Z substantially as described and shown for the
purpose specified.
L 1
T 1000
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.