Improvements in Centrifugal Pumps.
Year: 1899

page_text: Date of Application, 31st Jan., 1899-Accepted, 1st Apr., 1899
COMPLETE SPECIFICATION,
Improvements in Centrifugal Pumps.
I, FRITZ GUSTAF LUNDWALL, of Helleforsnäs, in the Kingdom of Sweden,
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: -
In order to make a centrifugal pump very light and effective the pump has
been provided with an air-chamber, within which the centrifugal body freely
rotates, above the liquid level formed in the air-chamber. The device has proved
to be in all respects very advantageous, except however as regards the difficulty
of retaining the necessary quantity of air in the chamber for keeping the water-
level in a low position. If the air leave the air-chamber, then the water finally
rises around the centrifugal body, which in such case then rotates in the water
and not freely above its surface. That the air is by degrees removed from the
chamber depends of course on the fact that the water, when ejected by the centri-
fugal machine, produces such a whipping of the water in the air chamber, that
the same is mixed with the air, which latter thus partly escapes with the water.
By means of this invention, which is based on the process of letting new quantities
of air into the chamber constantly during the rotation of the pump, the device
is so arranged, that the introduction of the air is effected automatically by means
of the rotating pump body or the centrifugal body itself.
In the accompanying drawings a force pump, provided with the improvement in
question is illustrated, in vertical section in Figure 1, whilst Figure 2 shows a
modification of the centrifugal body.
The centrifugal pump is divided into two chambers, one of which c forms a
continuation of the suction pipe a supporting the centrifugal body, while the
other chamber e is connected with the tubular shaft d of the centrifugal-machine.
Through the lower open end of this shaft, the outer air may enter in and pass
upwards through the shaft and through the chamber e, which in Figure 1
surrounds only the upper side of the water chamber c, while in Figure 2 the lower
side of the water chamber c is also surrounded by the air-chamber e. In this
latter case the different parts of the chamber e may be connected with each other
for instance by means of tubes or in any other suitable manner. As shown by
the drawing the chambers c and e meet at a suitable angle right inside the edge
of the centrifugal body and merge into a single exit and, if desired, the parts f
of the centrifugal body can by means of a screwed arrangement or in another
way be made removable, so that the mutual outlet openings of the chambers c
and e at the periphery of the centrifugal body can be adjusted relatively to the
quantity of air required.
When the water sucked into the tube a rushes out through the chamber c
there arises a suction outwards in the chamber e. In this way the chambers form
a circular ejector for the air which arrives through the tubular shaft, and which
passes in a uniform current up through the shaft and through the chamber e
to the edge of the centrifugal body, where the air enters into the chamber b,
simultaneously with the water, thus preventing the water level from rising.

page_text: The ejection action of the centrifugal pump such as just described remains of
course the same, even if the pump be not inserted in an air-chamber. Thus this
centrifugal pump can be adapted for different purposes, for instance as air pump
alone, and for making electric lamps and the like, where the most complete
vacuum is wanted. There is therefore no objection in letting for instance mercury
or some other heavier fluid pass up through the pipe a and the chamber c instead
of water for the purpose of increasing the effect. An air pump of that kind has
not only the advantage of having a great efficiency but is moreover very easy to
handle and takes but little place.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
A centrifugal pump in which the rotating pump body or centrifugal body is
divided into two or more annular chambers (c, e) concentric with the rotating
shaft and open at the periphery, the one of which (c) is connected with a liquid
receptacle and the other chamber or chambers (e) with the air or other fluid,
and which chambers coincide at the periphery in such a way that the liquid
flowing through the liquid chamber (c) produces a suction in the other chamber
or chambers outwards to the outlet, whereby a quantity of air or other liquid,
may be thrown out at the circumference together with the liquid entering in the
centrifugal body and the centrifugal pump thus forms a circular ejector, sub-
stantially as herein before described.
Dated this 27th day of January 1899
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.