Improvements in Pumps.
Year: 1897

page_text: Date of Application, 15th Mar., 1897--Accepted, 12th June, 1897
Improvements in Pumps.
I, JOHANN STUMPF, of 19 Lessing Street, of Berlin, Kingdom of Prussia,
German Empire, Professor 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 :-
In the pumps as constructed up to now it has not yet been possible to effect the
closing of the valves exactly in the moment in which the piston changes its
direction; even with compulsorily actuated valves the closing of the latter
occurred only after the piston has arrived at the end of its path. This may be
explained in a simple manner by the valves still letting pass water in the moment
of change of stroke of the piston in consequence of the evacuating and displacing
actions arising within the pump.
The present invention relates to a valve gear by aid of which the valves may
be closed not only just in the moment of change of stroke, but, if desired, even
before that change. This result is attained by effecting within the pump-space,
by aid of a special organ, a change in the proportions of pressure shortly before
the change of stroke, so that on the plunger finishing its stroke, for instance the
sucking-stroke, the period of forcing lias already been initiated. This manner of
operation causes a shockless play of the valves and offers the possibility of greatly
increasing the speed of the pump. In carrying my invention into practice I make
use of an auxiliary plunger or auxiliary piston, which shortly before the change
of stroke of the main plunger actuates the valve (in a direction opposite, to the
direction of action of said main plunger) by producing an evacuating or displacing
effect upon the contents of the pump-space.
By aid of a suitable mechanism the auxiliary piston or auxiliary plunger is so
moved prior to every change of stroke, that, concerning for instance, the suction
valve said piston or plunger tends to close this valve by the pressure exerted upon
the contents of the pump-casing, previous to the main-piston arriving at its dead
point. On the other hand, concerning the delivery valve, the auxiliary plunger
tends by its evacuating action to close this valve before the main-plunger reaches
the other end of its path.
If desired, the auxiliary plunger may well be used for making the closing of the
valves dependant from a valve-gear, or compulsory respectively; for this purpose
the motion of said plunger may be directly transmitted to the valves by aid of
bell-crank levers or the like; these levers or their equivalents may be combined
with springs or other elastic organs.
In Figure 1 of the accompanying drawing I have shown a vertical section
through a pump with a differential plunger a, the latter actuating in known manner
the suction-valve b and the delivery-valve c. The auxiliary plunger d is located
opposite to the main-plunger a and is operated by the mechanism shown in plan in
Figure 2. This mechanism consists of a rod e, a double-armed lever e¹ and a rod e 2,
the latter transmitting the movement of the lever el to the auxiliary plunger d.
The rod e is reciprocated from the engine driving the pump. To transmit motion
from the plunger d to the valves b and c there are arranged within the valve-casing
the bell-crank levers f¹f2.
The manner of action of the lower bell-crank lever f2 upon the suction-valve b
on the plunger d being moved inwards is, I think, intelligible from the drawing

page_text: without any detailed description. In order to prevent the valve from being
improperly operated in case of too great an extent of motion of the valve-gearing
mechanism the valve b is provided with a spring g the tension of which is
regulated by means of a nut g¹, in such a manner, that the valve is closed in due
time.
с
The delivery valve is more distinctly shown in Figure 3. The action of the
auxiliary plunger, or of the bell-crank lever f¹ respectively, on the delivery-valve f¹
is an indirect one. A spring g 2 inserted into the boss of the spider of the valve c
tends constantly to close this valve, the tension of said spring being transmitted to
said valve by a rod or spindle g 3. During the period of forcing however, the
spring 92 is rendered inoperative by the lever f, the latter being then moved
against the cap 94 which is secured to the lower end of the rod g 3 and supports
one end of the spring. At the end of the period of forcing, on the auxiliary
plunger making its back-way, the spring g2 is freed from the action of this
plunger so that the spring is able to draw or press the valve e down upon its seat.
The general manner of action of the whole arrangement is easily to be
understood: During the period of sucking the auxiliary plunger assumes about
the position shown in Figure 1. Shortly before, and during, the change of
direction of the main plunger the auxiliary plunger moves in the direction to the
interior of the valve casing and there is thus a certain quantity of water supplanted
out of this casing. In consequence of this supplantation of water (and, may be,
also in consequence of the downward movement of the bell-crank lever f2, as it is
acted on by the auxiliary plunger) the sucking-valve is closed. During the
delivery period the effective part of the auxiliary plunger is inside the valve-
chamber, and keeps both the bell-crank levers in working position. The lower
lever presses the suction valve down upon its seat, as has already been mentioned,
and the upper lever relieves the delivery valve c from the pressure of the spring g 2
(Figure 3). Near the end of the stroke of the main plunger the auxiliary plunger
moves again outwards, so that there results a sucking or evacuating action which
in connection with the then freed spring 92 causes an exact closing of the delivery
valve c.
In Figures 4-7 I have shown my invention applied to a double-acting pump.
In general the arrangement is the same as afore described, there are only some
constructive alterations, as fully described hereinafter. The general arrangement
is best to be seen from Figures 4 & 5, whereas the particular construction chosen in
this case is represented in Figures 6 & 7.
The auxiliary plunger d, Figure 6, acts upon the suction-valve band the
eduction-valve e in exactly the same manner as has been afore explained, i.e. by
producing an evacuating or displacing action within the space between said two
valves. A compulsorily transmission of the movement of the auxiliary plunger d
to the valves occurs, however, only with regard to the valve b, whereas for com-
pulsorily closing the valve ca special mechanism is provided. The conpulsory
operation of the valve 6 from the plunger d is brought about by aid of a bell-crank
lever f2, in very near the same way as has been described with regard to
Figure 1.
To compulsorily operate the valve c there is also made use of a bell-crank
lever (f); this lever in its turn being actuated from a rod d¹ which is arranged
in a manner very similar to the auxiliary plunger d. To move the plunger
piston d and the rod d' I connect both these parts to a rock-disk h which is
operated from the engine driving the pump. The disk h (Figure 4) oscillates the
vertical spindle k (Figures 4 & 6), by aid of the rod and the crank-arm h2.
The oscillating vertical spindle k then operates the parts d and d¹ by means of the
crauk arms (Figure 7) and the connecting rods k2. In all other details the
manner of action of the parts d and d¹ is exactly the same as afore described, for
the reason of which I abstain from giving the same explanations a second time.
It is a matter of course that also in a double-acting pump the auxiliary plunger
may be used for compulsorily moving both the valves; and it is further clear that

page_text: in a single-acting pump the auxiliary plunger may be caused to act (compulsorily)
upon one valve only whereas the other valve is compulsorily actuated by other
means, for instance such as have been shown in Figure 6.
It is not indispensably requisite to connect the means for compulsorily moving
the valves with the means for moving the auxiliary piston to and fro; these means
may be perfectly separated one from the other; and finally, instead of employment
an auxiliary plunger, I may make use of an auxiliary piston that works within a
conduit or channel connecting the valve chamber with either the sucking-chamber
or delivery-chamber of the pump or connecting both these chambers with each
other.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a pump, the combination with the working piston or plunger proper, and
with the induction- and eduction-valve, of an auxiliary piston or plunger adapted
to act upon said valves by producing an evacuating or displacing action within the
valve-chamber of the pump, substantially as and for the purpose set forth.
2. In a pump, the combination with the working piston or plunger proper, and
with the induction- and eduction-valve, of an auxiliary piston or plunger adapted
to produce an evacuating or displacing action within the valve-chamber of the
pump; and means for compulsorily transmitting the movements of said auxiliary
piston or plunger to oue or the other or both said valves, substantially and for the
purpose as set forth.
JOHN STUMPF,
By Geo. H. Rayner,
Agent for the Applicant.