Improvements in Direct Acting Pumping Engines.
Year: 1894

page_text: COMPLETE SPECIFICATION.
Improvements in Direct Acting Pumping Engines.
I, GEORGE DE LAVAL, residing at Moore Avenue, Warren in the State of
Massachusetts, United States of America, Mechanical 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 improvement is specially adapted to duplex water pumping engines, but it
is also available with air compressors and with both single and duplex pumping
engines that are direct acting.
In direct acting pumping engines it is generally advantageous to employ the
steam expansively, and efforts have heretofore been made for equalizing the power
exerted by combining with the engine a compensating mechanism to equalize or
nearly so the power exerted throughout the entire stroke; that is to say, the steam
engine acts directly upon the pump and also upon a compensating device while the
pressure is maintained in the cylinder, and when the cut-off operates and the
pressure commences to decrease, the compensating mechanism acts to augment
the force of the steam while the piston finishes the stroke.
My present improvements apply to pumping engines of this general character,
and I combine with the cross-head of the direct acting pumping engine, toggle
levers, a cylinder and fluid pressure acting upon the piston, so that when the steam
pressure is acting upon the piston, piston rod and cross-head, the fluid pressure in
the cylinder is augmented and becomes the resistance to the movement of the
engine, and after the cut-off takes place the fluid pressure acting through the toggle
levers compensates the loss of efficient force as the steam acts expansively, thereby
equalizing the stroke and movement of the direct acting pump.
When this improvement is applied with a duplex pumping engine, the valve of
one engine receives its motion in connection with the movement of the other
engine; but I remark that the valve motion and valve may be of any desired
character and the cut-off may be operated as usual, as these parts form no necessary
portion of my present invention.
In the drawings,
Fig. 1 is a side view partially in section and Fig. 2 a cross section representing
my compensating device in which the slide-block of the toggle mechanism moves
horizontally.
Fig. 3 is a side view partially in section, and Fig. 4 a cross section of the frame
and elevation of the toggle mechanism with the slide-block moving vertically.
A represents part of one end of a steam cylinder, and B' part of one end of a
pump in which cylinders pistons are employed as usual that are connected by the
rod or rods C, and B is the cross-head which may be of any desired character and
preferably provided with slide-ways E, although these may be dispensed with,
and F is a cylinder in which a fluid under pressure is provided for acting upon the

page_text: piston G or plunger G¹, and at 2 is represented a pipe passing off to a cylinder or
other vessel containing air or gas under pressure, or to a suitable column or head
of water or other liquid. under the desired pressure..
The compensating lever H, Fig. 1, is pivoted at 3 upon a suitable connection to
the frame of the engine, and one end of the compensating lever H is connected to
the cross-head B by a link 4, and the other end of the compensating lever His
connected to the toggle lever K that is pivoted at 5 to the piston G. It is
advantageous to make the toggle levers of about the same length between the
fulcrums 3 and 5 and the joint 6 of the respective parts; and in Fig. 1 the lever K
is connected at its upper end to the slide-block L'in the ways M; and it will now
be apparent that when the cross-head B is moved in either direction by steam
acting in the cylinder A, the fluid in the cylinder F is compressed by the piston G
until the centers 3 5 and 6 come into line, which is at the half of the stroke of the
piston, and during this part of the movement the power of the steam has been
partially consumed in compressing the fluid in the cylinder F, and during the
remainder of the stroke the expansion or pressure of the fluid in the cylinder F
acts upon the piston G, and by the toggle levers H K the force is exerted in
completing the movement of the cross-head B; and it is advantageous to regulate
the fluid pressure acting in the cylinder F upon the piston G with reference to the
steam pressure acting in the cylinder A and according to the point at which the
steam is cut off, so as to equalize as nearly as possible the resistance to the move-
ment of the steam piston during the first half of the stroke and the compensating
and equalizing action of the piston G in completing the stroke of the direct acting
pump.
In Fig. 2, I have represented two cylinders F side by side, two toggle levers K
and two compensating levers H, and one slide-block L to which the upper ends of
the toggle levers K are connected. This arrangement allows for balancing the
action of the parts, but it will he apparent that only one cylinder F may be
employed if desired; and I remark that under all circumstances the pressure
exerted by the piston G is taken through the toggle portions of the levers H
and K upon the pivot or rock shaft 3, so that there is but little friction upon the
slide-block L, and the movement of the parts is with but little friction, and the
pressure upon the piston G exerts a power in moving the cross head. B that is
augmented toward the end of the stroke as the toggle levers approach toward a
right angle to each other.
In Figs. 3 and 4, the compensating mechanism acts in the same manner as in
Figs. 1 and 2, but I am enabled to dispense with the links 4 by placing the slider
block L in vertical ways instead of horizontal, so that the piston rod 7 of the
plunger or piston G is connected directly to the slider block L' in the vertical
slideways M', and with this arrangement the pivot 14 at the upper end of the com-
pensating lever H' can be connected directly to the cross-head B and at the lower
end 15 directly to the slider block L', and the pivot or rock shaft 13 is provided
with a link O forming one half of the toggle, the lower end of the link O being
connected at 16 to the middle portion of the compensating lever H₁, and the
operation of these parts is the same as before described with reference to Figs. 1
and 2, the lower end of the lever H' and the link O forming the toggle and the
cross-shaft or pivot 13 forming the resistance to the pressure, so that the parallelism
of the cross-head B in its movement is not disturbed, and the expansive pressure
acting in the cylinder F exerts the greater force near the end of the movement to
compensate or equalize the less force of the steam as it acts expansively.
By reference to Fig. 4, it will be seen that it is advantageous to employ two
compensating levers H¹ and two links O upon the rock shaft 13, so that the action
may be equal at each side of the frame, and in this case it is more convenient to
make use of only one cylinder F in which the confined pressure acts for compensating
or equalizing the movements of the parts.
I have preferably shown the compensating rig attached between the steam and
pump cylinders, but the same can also be arranged at the end of the pump cylinder

page_text: which will be the preferable way when in an old engine of the direct acting type.
for using steam the full stroke is to be changed into a high duty pump, and cutting
off the steam at a part of the stroke.
Having now particularly described and ascertained the nature of my said inven-.
tion and in what manner the same is to be performed, I declare that what I
claim is :
First. The combination with the steam cylinder and direct acting pump and:
piston rods and cross-head, of slides and a connecting frame between the cylinders,.
piston or plunger and cylinder in which a fluid under pressure acts on the piston
or plunger, a compensating lever at one side of the frame and a link forming a.
toggle to compress the fluid at the middle of the stroke of the engine and a fixed.
pivot for the toggle on the connecting frame, substantially as specified.
Second. The combination with the steam cylinder and direct acting pump and
piston rods and cross-head, of slides and a connecting frame between the cylinders,.
a piston or plunger and a cylinder in which a fluid under pressure acts on the piston.
or plunger, two separate compensating levers, one at each side of the frame and
jointed at their upper ends to the cross-head, links forming with the levers toggles.
to compress the fluid at the middle of the engine stroke, and fixed pivots on the
frame for the toggles, substantially as specified.
Third. The combination with the steam cylinder A, pumping_cylinder B',
connecting rod C and cross-head B, of the compensating lever H, the link 4.
connecting the upper end of the compensating lever to the cross-head, the pivot 3,.
the cylinder F in which a fluid under pressure is provided, the piston G, toggle
lever K pivoted to the compensating lever, and the slide-block L in the slideways M,.
substantially as set forth.
Fourth. The combination with the steam cylinder, pumping cylinder, connecting
rod and cross-head, of the compensating lever, a connection between the upper end.
of the compensating lever and the cross-head, the pivot for the lever, a cylinder in
which a fluid under pressure is provided, a piston therein and a toggle lever pivoted
to the compensating lever, and a slide-block in the slideways, substantially as set
forth.
Fifth. The combination with the steam cylinder A, pumping cylinder B' and.
the connecting frame, of the piston rod C, cross-head B, the compensating levers H,
one at each side of the connecting frame, the rock shaft forming a pivot and
connecting the two levers, the compensating cylinders F and pistons G, the toggle
levers K connecting the pistons G and compensating levers H, the slide-block L.
and slideways M for the same, substantially as set forth.
Dash of T.... 1904
BREWER & SON,.
Agents.