Improvements in Duplex Pumping Engines.
Year: 1895

page_text: Date of Application, 2nd Dec., 1895
Complete Specification Left, 2nd Sept., 1896-Accepted, 7th Nov., 1896
Improvements in Duplex Pumping Engines.
We PHILIP FRANCIS ODDIE and GUSTAV HESSE both of 130 Larkhall
Lane, Clapham, in the County of Surrey, Engincers do hereby declare the nature
of this invention to be as follows:-
This invention relates to improvements in duplex pumping engines in order to
obtain better results by using to better advantage the expansive force of steam, or
other suitable elastic fluids and in part is designed to further develop the invention
described in the Specification of Letters Patent granted to the said Philip Francis
Oddie and bearing date the 22nd day of April 1892 No. 7617.
In carrying out the present invention we make use of the inclined web or groove
on the trunk of the piston of one cylinder for actuating the valve for the admission
and emission of steam to the other cylinder as described in the said former
specification but instead of working the valves in a recess formed between the two
piston heads as described we make these inclined or equivalently shaped, grooves
engage each a plate or part which forms a portion of or is connected to a slide
valve, piston valve, or equivalent valve, each said plate or part may be formed
with or as an anti frictional or rolling surface.
This slide valve or piston valve traverses a valve face, having suitable ports in a
steam chest, and is so constructed and operated that no steam leaks from the steam
chest to the interior of the working cylinder.
This valve operates to admit and emit steam or air to the companion cylinder of
the duplex pumping engine and in like manner a similar valve operates to admit
and emit steam to the first cylinder.
In order to facilitate the working of the steam expansively each cylinder is
provided, in addition to the main steam valves already described, with an expansion
valve which operates to cut off the admission of the steam before the end of the
stroke of their respective pistons.
Each expansion valve is operated by means of an arm or part which is attached
rigidly or adjustably to the plate which actuates the slide valve of the companion
cylinder; the arrangement being such that, while the motion of each piston by
means of the inclined groove operates the main slide valve of its fellow cylinder it
also actuates and controls the expansion valve which regulates the cut off of steam
to its own cylinder.
The expansion valves may be arranged to work on the back of the slide valves
or where piston valves are employed for the main valves, they can be piston valves
and work in the piston valve cylinders.
In order to compensate for the fall of pressure in the cylinder due to the
expansion of the steam after cut off the pistons are made sufficiently heavy that
the momentum generated by their motion during the first part of the stroke shall
be given back during the latter part of the stroke and the effective pressure on the
pump piston or plunger to which the steam piston is connected by means of the
piston rod; is maintained approximately uniform throughout the length of
the stroke.
By attaching or forming a larger and smaller piston at each end of the trunk on
which is the inclined slot or groove and by forming the casing with a larger and
smaller cylinder at each end to receive the pistons the engine may be compounded

page_text: and the steam further expanded in the larger cylinder after having done work in
the smaller cylinder.
The expansion valves may be arranged to cut off either for each high pressure
cylinder or for each low pressure cylinder or the expansion valves may be made to
cut off the steam for both the high and low pressure strokes, or for the high
pressure stroke of one duplex cylinder and for the low pressure stroke of the
other.
We prefer to effect the guidance of the steam pistons and thereby to counteract
any tendency of those pistons to acquire a turning motion owing to the form of
the inclined slots and further to help support the pistons especially for horizontal
pumping engines, by means of a stud or support preferably eccentrically projecting
from the end cover or equivalently mounted.
Dated the 2nd day of December 1895.
WM. BROOKES & SON,
55 & 56 Chancery Lane, Loudon, Agents for the Applicants.
Improvements in Duplex Pumping Engines.
We PHILIP FRANCIS ODDIE and GUSTAV HESSE, both of 130 Larkhall Lane,
Clapham, in the County of Surrey, Engineers 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 improvements in duplex pumping engines in order to
obtain better results by using to better advantage the expansive force of steam, or
other suitable elastic fluids and in part is designed to further develop the invention
described in the Specification of Letters Patent granted to the said Philip Francis
Oddie, and bearing date the 22nd day of April 1892 No. 7617.
In carrying out the present invention we make use of the inclined web or
groove on the trunk of the piston of one cylinder of an engine here shown as of
the form shewn in the aforementioned specification for actuating the valve for the
admission and emission of steam to the other cylinder as described in the said
former specification but instead of working the valves in a recess formed between
the two piston heads as described we make these inclined or equivalently shaped,
grooves engage each a plate or part which forms a portion of or is connected to
a slide valve, piston valve, or equivalent valve. Each said plate or part may be
formed with or as an antifrictional or rolling surface.
This slide valve or piston valve traverses a valve face having suitable ports in a
steam chest, and is so constructed and operated that no steam leaks from the steam
chest to the interior of the working cylinder.
This valve operates to admit and emit steam or air to the companion cylinder
of the duplex pumping engine and in like manner a similar valve operates to
admit and emit steam to the first cylinder.
In order to facilitate the working of the steam expansively each cylinder is
provided, in addition to the main steam valves already described, with an expansion
valve which operates to cut off the admission of the steam before the end of the
stroke of their respective pistons.
Each expansion valve is operated by means of an arm or part which is attached
rigidly or adjustably to the plate which actuates the slide valve of the companion.
cylinder the arrangement being such that, while the motion of each piston by
means of the inclined groove operates the main slide valve of its fellow cylinder
it also actuates and controls the expansion valve which regulates the cut off of
steam to its own cylinder.
The expansion valves may be arranged to work on the back of the slide valves

page_text: or where piston valves are employed for the main valves they can be piston valves
and work in the piston valve cylinders.
In order to compensate for the fall of pressure in the cylinder due to the
expansion of the steam after cut off the pistons are made sufficiently heavy that
the momentum generated by their motion during the first part of the stroke shall be
given back during the latter part of the stroke and the effective pressure on
the pump piston or plunger, to which the steam piston is connected by means of the
piston rod, is maintained approximately uniform throughout the length of the
stroke.
By attaching or forming a larger and smaller piston at each end of the trunk
on which is the inclined slot or groove and by forming the casing with a larger
and smaller cylinder at each end to receive the pistons the engine may be compounded
and the steam further expanded in the larger cylinder after having done work in
the smaller cylinder.
The expansion valves may be arranged to cut off either for each high pressure
cylinder or for each low pressure cylinder or the expansion valves may be made
to cut off the steam for both the high and low pressure strokes, or for the high
pressure stroke of one duplex cylinder and for the low pressure stroke of the other.
We prefer to effect the guidance of the steam pistons and thereby to counteract
any tendency of those pistons to acquire a turning motion owing to the form of the
inclined slots and further to help support the pistons especially for horizontal pumping
engines, by means of a stud or support preferably eccentrically projecting from
the end cover or equivalently mounted.

page_text: but they may be of other convenient form such as a curve or combination of curve
and other form.
d is the valve face showing the openings leading to the valve passages the face
of which is shown separately by Fig. 9 (1) (1) and (2) being the admission and
emission ports, according to circumstances as in an ordinary engine employing
slide valves.
his one of a pair of slotted holes, of which the other is not shown, communi-
cating with the interior of the cylinders and through which the guides or pieces 41
connected to the valves 2 (according to the arrangement shewn in Figs. 1, 3, 4
and 5); whilst in the arrangement shown in Figs. 6, 7 and 8, the guide pieces
instead of being directly connected to the valves are attached to intermediate
plates which also serve as covers for the said holes to retain the steam.
These guides actuated by the inclines a¹ serve to actuate the valves for
admission and emission of steam and by their connections to operate the expansion
or cut off valves whose purpose will be more particularly described hereinafter.
Referring to Figs. 4 and 5, the parts are here shown as simply blocks,
with parallel sides and inclined ends bolted on their edges to the valve plate h³
but they may be as shown in Figs. 10 and 11 or they may be varied in form.
To these valve plates 2 (Figs. 4 and 5) are attached by the arms h¹ expansion
valves one being the inside and the other the outerside valve for the cut off.
(3) (4) are stean passages through these valve plates or slide valves h³ com-
municating with the ports (1) and (2).
By the use of these expansion valves each piston is enabled to control the
cut off of its own admission of steam whereby the amount of steam used is reduced
and the stroke is rendered more positive and the motions of the pistons are
reduced before the end of the stroke is reached thereby facilitating the attainment
of enhanced speed.
The object of making the extensions of the pistons as shown and of rendering
them weighty, is that they shall be better adapted by their increased momentum
to attain their complete strokes when by the cut off of steam their motive power
is reduced and they might otherwise prematurely come to a standstill with its
consequent inconveniences.
In the modification Figs. 6, 7 and 8, the two pairs of expansion pistons 1, 1, 11, 1,
forming each an adjustable double valve which valves reciprocate in the passages 12, 12
Each pair of
of the main valves 13, 13 of which (5) and (6) are the steam channels.
pistons 1, 1, and 1', ', are mounted on a rod and these rods are each secured (as
shewn by nuts) to an arm on or part of one of the covers h³. In order to facilitate
adjustment relatively of the pairs of pistons 1, 1, and 1, 1, respectively the ends of
the rods are each formed with a screw thread corresponding with a female
thread in each of those pistons and by turning the said rods from the outside in any
convenient manner, as by means of a key applied to a square end of said rod,
these pistons may be caused to approach or recede from each other and take up
positions adapted to render the cut off earlier or later as may be required.
The rods are arranged in threaded openings formed eccentrically (see Fig. 8)
of the circles of the valve passages 12, 12.
m is a bridge plate covering the openings of the valve chambers and overlying
the valves and serving thereby to remove eccessive pressure and consequent
friction in movement therefrom.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what
we claim is :-
-
In a duplex pumping engine,
1. The construction, arrangement and use of weighted pistons whose momentuin
is utilised for the purpose of enabling those pistons to complete their strokes after
the motive pressure of steam has been reduced by means of the cut off, substantially
as and for the purpose set forth and shewn by the drawings Figs. 1 and 2.

page_text: 2. The construction, arrangement and use of the weighted pistons, as specified
and claimed in Claim 1 in combination with an arrangement of valves for the
purpose of cutting off the supply of steam so as to utilize the expansive force of
the steam already supplied to the cylinder, substantially as described and shewn
by the drawings.
3. The construction and use of valves and parts co-operating therewith regulating
the expansive force of the steam as and for the purpose described and as shewn with
reference to Figs. 4 and 5.
4. The construction and use of the arrangement of valve apparatus with double
pistons and adjusting means therefor so that the "cut off" may be varied as may
be required with increased facility, substantially as set forth and shewn by Figs. 6, 7
and 8.
the
5. The general construction, arrangement and use of parts, substantially as and for
purpose described and shewn.
Dated the 1st dose of Santambar 1896
WM. BROOKES & SON,
55 & 56 Chancery Lane, London, Agents for the Applicants.