IMPROVEMENTS IN PUMPS
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by Gerard Wenzeslaus von Nawrocki at
the Office of the Commissioners of Patents on the 30th March 1881.
A communication from Carl Blasendorff, of the City of Berlin, Germany.
GERARD WENZESLAUS VON NAWROCKI, Proprietor of the Firm of J. Brandt
& G. W. v. Nawrocki, Patent Solicitor and Engineer, of 125, Leipzigerstrasse,
Berlin, Germany. IMPROVEMENTS IN PUMPS." A communication from Carl
Blasendorff, of the City of Berlin, Germany,
"
The Invention relates, to pumps which are required to draw water or other fluid
from greater depths than the maximum suction height of the fluid to be raised.
This is effected by the employment of a hydraulic spear or rod, the pipe of which
serves also as a rising main, and of one or more auxilliary pumps placed at certain
depths in the well.
The Invention consists of the following arrangements:-An ordinary suction
pump without suction valve, but with valved piston or bucket, is connected by a
pipe with an auxilliary pump with differential pistons. The smaller differential
piston is an ordinary suction piston or bucket with a valve, and is connected by a
rod with the larger differential piston. The latter piston is larger than the former
in proportion to the head or lift. (Förderhohe.)
The auxilliary pump communicates by the aforesaid pipe with the first
mentioned pump, and is furnished with a suction valve and suction pipe.
The larger differential piston is to be loaded more or less according to the head.
This pump works as follows:-
Assuming that both pumps as well as the pipes are filled with water, and that
the larger differential piston is near its highest position; if the piston of the
ordinary pump is moved downwards, the water passes through the valve of the
said piston to the upper side thereof, the piston then being moved upwards it
draws the water out of the auxilliary pump. Supposing that the load on the
larger differential piston is regulated so that the pressure of the atmosphere suffices
to press the said piston down, if the piston of the ordinary pump is now moved
downwards again, the column of water in the pipe connecting the two pumps
causes the two differential pistons to rise, whereby the smaller of the two draws up
water through the suction pipe if the column of water is heavy enough.

page_text: During the complete upward stroke of the piston of the ordinary pump, a
quantity is drawn from the differential pump which corresponds to the space swept
through by the larger differential piston, and there re-enters into the auxilliary
pump during a complete upward stroke of the differential pistons, a quantity of
fluid equal to the differential space swept through by the two pistons.
When the larger differential piston has reached the end of its stroke, a further
downward movement of the piston of the ordinary pump effects the opening of its
valve, so that as much fluid passes to the upper side of the said piston as was
previously drawn up by the smaller differential piston.
In some cases the larger differential piston must be unloaded or balanced.
This is effected most conveniently by a lever and weight.
In other cases the larger differential piston must be loaded by means of weights,
a column of fluid of suitable height, or an air vessel.
Instead of an ordinary suction pump being used to draw from the differential
pump, a force pump may be used.
In another arrangement a force pump with outlets for fluid at various heights is
employed, such outlets being provided with cocks or valves. In order to obviate
the prejudicial influence of variable heads on the auxilliary pump, the force pump
is furnished with differential pistons. Both these pistons are constructed as solid
pistons.
The connecting pipe is in communication with the space between the two
pistons, and the space under the smaller of these two pistons is also connected with
the said pipe by a branch pipe which is fitted with a suction valve.
It is necessary that the areas of the differential pistons of the force pump should
stand in the same relation to each other as the pistons of the differential pump,
whereby neither too much nor too little working fluid remains between the pistons
of the force pump.
At the downward movement of the two pistons of the force pump, the suction
valve closes, so that the pressure of the water column in the rising main is kept out
of the auxilliary pump.
With very long conduits another modification may be used with advantage; in
this arrangement the piston of the lift pump is constructed as follows:-
A cup leather is screwed fast between two rings which are furnished with screw
threads; to the piston rod above the piston there is fixed a solid plate, and to the
same rod below the piston is fixed a perforated plate in such manner that the
distance between the plates is larger than the thickness of the piston. When both
pumps and the pipes are filled with water, and the piston rod is pressed down-
wards, the upper plate of the piston of the lift pump lays on the upper ring of such
piston, so that the passage of the fluid through the said piston is prevented.
the piston rod of the lift pump is drawn up, the upper plate rises from
off the upper ring and the lower perforated plate comes against the lower ring,
and the fluid is free to pass through the piston to the upper side and to flow
If now,
away.
It is evident that several auxilliary pumps of the kind above mentioned may be
employed one above the other, but it is to be remarked that all these auxilliary
pumps, with the exception of the deepest one, must be provided with a suction
valve.
It may further be remarked that the auxilliary pump with differential pistons
may be divided into two separate pump cylinders, each with one piston, in which
case the lower pump cylinder forms the suction pump and is provided with suction
and delivery valves, and the piston of this cylinder is connected with the piston of
the working cylinder and is to be suitably loaded.
According to another modification a twin auxilliary pump is employed, which
can be connected with a double acting pump without suction valve or with two
single acting reciprocating pumps. This auxilliary pump consists of two suction
cylinders with suction pistons and two suction and two delivery valves, also of a
working cylinder with a working piston; these three pistons are concentric and

page_text: connected together by one rod. In this case the balance weight is replaced
alternately by one of the water columns of the connecting pipes.
Instead of the lift pump with peculiarly constructed piston above referred to, a
pump arranged with a slide valve and solid piston may be employed, and a double
acting pump arranged on the same principle with two slide valves may be employed
with the above mentioned twin pumps.