Improvements in or connected with Direct Acting Steam Pumps.
Year: 1897

page_text: Date of Application, 2nd Mar., 1897-Accepted, 15th May,
1897
Improvements in or connected with Direct Acting Steam Pumps.
A communication by GUSTAV HONEGGER, of 49 Neue Hochstrasse, Berlin, 'in
the Empire of Germany, Engineer.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of The Agency for
Foreign Patent Solicitors, 6, Lord Street, Liverpool and 6 Bank Street,
Manchester, both in the County of Lancaster, 118 New Street, Birmingham, in
the County of Warwick, and 322 High Holborn in the County of Middlesex,
Civil 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:—
Duplex steam pumps, notwithstanding their great advantages, have always only
a limited use, and the main reason for this is the very great consumption of steam.
As the resistance which a direct acting steam pump has to overcome remains
constant, the pressure on the pistons must also remain constant during the whole
stroke. No expansion of the steam may therefore take place in the cylinders,.
that is to say, the construction of the duplex steam pumps at present employed
requires a full charge which explains the large cousumption of steam.
As the power on the pistons during the expansion of the steam in the cylinders.
constantly diminishes, whilst that on the pump plunger remains constant, the
surplus or additional power, which during the period of admission acts on the steam
pistons must be stored up if it be desired to work with expansion, and again given
up during the expansion period, so that during the whole stroke a constant
pressure acts on the pump plunger which corresponds to the inean pressure on the
steam pistons.
To this end, one or more flywheels have hitherto usually been employed, in which
the excess work of the admission period is stored up and again delivered during
the expansion period.
The use of flywheels has however its drawbacks, as there comes in question not
merely conditions of space but also of stability and the cost of manufacture, and
further a precise equalisation cannot be attained even with flywheels.
This invention has for its object an improved steam pump which works without
a flywheel and yet with expansion. It is provided with a resistance, the use of
which removes all the drawbacks of duplex steam pumps hitherto employed. The
surplus power which acts on the steam pistons is thus stored up in the resistance
during the periods of admission whilst on the other hand it is given up during the
periods of expansion. The actual power exerted on the pump plunger remains
therefore constant during the whole stroke, and the running of the pump therefore
s even, regular and free from shock.
The invention will be described with reference to the accompanying drawings,
n which:-
Figure 1 is a side elevation partly in section of a duplex steam pump in which
weight is employed as resistance and storer or accumulator of power;
Figure 2 is a vertical cross section of Figure 1;
Figures 3 and 4 show similar views of a duplex steam pump in which a pressure
ylinder is employed as resistance or power storer ;
Figures 5 to 7 are diagrams showing the resistance and work.
'

page_text: In the form of construction shown in Figures 1 and 2, the piston rod a of a
duplex pump 6 is connected with a rack d guided in guides c, which rack engages
with a toothed segment f mounted in bearings e. At each end of the shaft g of
this toothed segment there is keyed a crank h and both of these cranks hare
connected by means of connecting rods i with a weight k. In a movement of the
pistons from left to right, the toothed segment f together with the cranks will
traverse points 1-9 on the scale of the diagram Figure 7, whereby the weight k
will be raised from the point 1 to the point 5 and will in turn sink from the point 5
to the point 9. The weight k exerts a pressure on the steam pistons through the
intermediate parts i hfd which pressure equals a maximum so long as the cranks h
are at the point 1; the pressure is however opposed to the actual movement of the
piston rods a and diminishes constantly from 1-5, becomes equal to O at point 5,
increases again constantly from point 5 to point 9 and reaches its maximum again
at point 9. The pressure which the weight exerts during the periods 5-9 acts
however assistingly on the pistons.
Figure 5 shows how the action of the weight diminishes from point 1 to point 5,
becomes 0 at point 5 and increases in a reverse direction from point 5 to point 9
again. During the periods of admission to the steam pistons there is thus, apart from
the pressure which the forwarding of the water exerts thereon, an opposed
resistance 1. 5 x, that is to say, this work is stored up in the weight k. During the
periods of expansion where the pressure of the steam diminishes, the power 1. 5.c
stored up in the weight k comes into play, which power is also shown in the
diagrams by the negative surface 5, 9, y. It is therefore added to the power
resulting or produced during the expansion period.
Figure 6 shows this equalisation.
The diagram u, v, y, a of the power acting on the steam pistons is altered by the
use of the resistance k into the diagram u, r, 5, 9, v, that is to say, the useful power
acting on the steam pistons is altered into a constant one in spite of the working
being effected by means of expansion.
In the modified form of construction shown in Figures 3 and 4, in place of a
weight a counter pressure cylinder r is employed, the piston m of which is connected
to the crank of the toothed segment by a connecting rod i. The cylinder r is
arranged to oscillate and is provided at its lower end with an opening s. A feed
pipe A is connected to the cylinder and conveys into a chamber B any suitable
medium of pressure, such as water under pressure, compressed air, or steam.
This
medium of pressure works on the piston m in the same way as the weight k in the
previously described example.
Either the forwarded column of water or fresh boiler steam may be caused to
act through the pipe A on the pistons m. The action of such a power storer
produced by a medium of power will be the same as in the example shown in
Figures 1 and 2.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by my
foreign correspondent, I declare that what I claim is :-
1. In direct acting steam pumps, the arrangement of a resistance consisting of a
weight or pressure cylinder, adapted by means of a toothed sector to act on the
piston rod and thereby on the steam pistons at the commencement of the admission
periods with its maximum power against the actual movement of the piston rod,
but constantly diminishing until in the middle of the stroke it is equal to 0, whilst
during the expansion periods it returns the power stored up in it in a constantly
increasing extent to assist the work effected by the expansion, with the object of
obtaining a constant pressure action on the pump plungers in direct acting steam
pumps working with expansion in spite of the diminution of pressure during the
whole duration of the stroke arising from the expansion in the steam cylinders and
of thus obtaining a quiet even working of the pumps free from shock substantially
as described.

page_text: 2. A form of construction of the herein described steam pump, characterised by
a steam cylinder being employed as resistance, which steam cylinder may stand
under the action of either the column of water forwarded, fresh boiler steam, or
compressed air, substantially as described.
Dated him and 1 of March 1907
WM. P. THOMPSON & Co.,
Agents.