Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
2080591
DESCRIPTION
PUMP HAVING A SINGLE OR A PLURALITY OF
HELICAL BLADES
TECHNICAL FIELD
The present invention relates to a vertical pump having
a single or a plurality of helical or spiral blades and,
more particularly, to a pump suitable for sewage treatment
or the like.
BACKGROUND AR~
Conventionally, in a vertical pump, a rotor having a
plurality of blades extending radially in a plane
perpendicular to a main spindle of the pump is arranged at a
lower position within a casing of the pump and is rotated to
execute drawing or suction of water from a lower end of the
casing.
However, this vertical pump has the following
disadvantages. That is, since the pump comprises the
plurality of blades which are so spread as to extend
radially in the plane perpendicular to the main spindle of
the pump, toward t]he casing, a passing area of water stream
or flow is limited or narrowed. Particularly, in a case
where sewage is su,-ked or drawn, cloths and solid matters
which may be contained in the sewage lodge within the pump.
Further, a centrifugal pump is known which is disclosed
in Japanese Patent Laid-Open No. SHO 57-181997, as a pump
having a single he:Lical blade.
However, such a centrifugal pump has the following
disadvantage. Tha-t is, since water drawn in a direction of
the main spindle o-F the pump flows in a direction
perpendicular to the main spindle, solid matters and the
like lodge within the pump.
Furthermore, depending upon water pumping environment,
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there may be a case where a vertical type non-blocked pump
is required.
It is an object of the invention to provide a vertical
pump which is non-blocked and which is large in lift and in
discharge quantity or delivery.
SUMMARY OF THE INVENTION
In accordance wit:h one aspect there is provided a vertical pump wherein
0 a plurality of blades are f;xedly mounted on a forward end of a rotary drive
shaft and wherein an outer peripheral portion of each of said plurality of blades
is in proximity with an inner surface of a casing characterized in that: said
casing extending in the direction of said rotary drive shaft has a bell mouth
5 fixed on a lower end of said casing and a portion of said casing, surrounding
said blades, has a configuration bulged in the form of a bowl; said blades are
helical in configuration, ~md are arranged with their phases equidistantly shifted
respectively about said rotary drive shaft; each said helical blade has a forward
~ end portion extending downwardly more than the lower end of said casing and
less than the lower end o:f said bell mouth; a plurality of twisted guide vanes is
arranged at a flow passa,~,e in an upper portion above said helical blades in said
bowl-shaped configuration portion of said casing; and said bowl-shaped
configuration portion of said casing, by which said helical blade and said guidevane are surrounded, is divided at a location between said blades and said guidevanes and at an intermed iate portion of said guide vanes, whereby said casing is
formed by three portions.
With such an arrangement of the helical blades, it is possible not only to
suck the fluid in the bell mouth 24 into the casing 20 positively but to preventthe blades, especially respective tips thereof, from being damaged by sucked
objects since the blades are protected by the bell mouth 24, so that the life span
of the blades can be extended in comparison with an arrangement in which the
rips of the blades are exposed.
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2 0 8 0 5 9 1
With the above arrangement, volumetric efficiency is
raised, and it is possible to raise the lift. Furthermore,
it is possible also to enlarge the caliber or aperture of
the pump so that the discharge quantity or delivery can
increase. Generally, since enlargement of the aperture of
the pump increases the dimension of the blade so that its
weight considerably increases, balance with respect to the
drive shaft of the blade is apt to be deteriorated by the
single helical blade so that harmful vibration is generated
in the pump and the efficiently of the pump is reduced. In
the pump according to an embodiment of the invention,
however, since the plurality of helical blades are arranged,
the balance is extremely improved so that vibration imparted
to the pump is extremelY reduced. In a case where there are
two helical blades, suction ports and discharge ports within
the casing are located shaft-symmetrically with respect to
the main spindle of t,he pump. Accordingly, balance becomes
superior. Moreover, also in a case where there are three
helical blades, since the suction ports and the discharge
ports are similarl;Y distributed symmetrically, there can be
produced similar advantages.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a schematic cross-sectional view showing a
vertical pump having a single or two or more helical blades,
according to the invention;
Fig. 2 is a partially cross-sectional view of a forward
end portion of the pump illustrated in Fig. 1, showing a
case having a single helical blade;
Fig. 3 is a partially cross-sectional view of a forward
end portion of the pump illustrated in Fig. 1, showing a
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case having two helical blades;
Fig. 4 is a bottom view of Fig.3; and Fig. 5 is a
bottom view showing a pump having three helical blades,
according to the invention.
BEST MODE FOR CARRYING OUT THE INVENTION
A pump having a single or a plurality of helical
blades, according to the invention, will be described below
in further detail with reference to the drawings.
Fig. 1 is a schematic view showing a pump 1 according
to the invention. A hub 8 is fixedly mounted on a forward
end of a rotary drive shaft 2 which is rotated by drive
means, for example, a motor (not shown). At least one
helical blade 10 is mounted on the hub 8.
When the drive shaft 2 is rotated, water is drawn from
a suction port 4 of a bell mouth 24 which is arranged below
a casing 20 of the pump 1. The drawn water is straightened
or uniformed by a plurality of twisted guide vanes 14 which
are arranged above the helical blade 10 at a location within
the casing 20, and is pumped up to a tube 18 at an upper
portion of the casing 20. It is required that the guide
vanes 14 gradually uniform the water flow pumped up
helically along the helical blade, so as to flow straight
within the tube 18, to eliminate evils such as vibration or
the like to the pump. For this purpose, the guide vanes 14
are twisted about 270~ . Moreover, the twisted guide vanes
14 are lengthened in order to obtain or produce adequate
uniforming of the flow.
As a result that the guide vanes 14 are lengthened, the
casing 20 is lengthened. Accordingly, the casing 20 is
divided into multi-stage portions 21, 22 and 23 at a
location between the helical blade 10 and the guide vanes 14
and at a location at an intermediate portion of each of the
guide vanes 14, for the purpose of assembling and
maintenance of the pump.
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Fig. 2 is a p rtially cross-sectional side elevational
view showing a principal portion of a lower end section of
the pump illustrated in Fig. 1, showing the pump 1 having a
single helical blade 10.
Description will be made to the helical blade 10. The
blade 10 has a configuration thereof wound helically about
the rotary drive shaft 2 through an adequate angle. The
blade 10 is mounted on the hub 8 at a proximal end portion
30 of the blade 10. An outer peripheral edge portion 32
opposite to the pr~ximal end portion 30 is in proximity with
an inner surface of the casing 20. The hub 8 and the
helical blade 10 may be formed integrally as a casting. A
forward end potion 33 of the helical blade 10 extends
downwardly less than a forward end portion 9 of the hub 8,
whereby the wide suction port 4 is formed. An interval
between the upper and lower blade portions serving as a flow
passage is adequately widened so as to allow cloths and
solid matters included in sewage and the like pumped up, to
pass.
When the drive shaft 2 is rotated, the pumped-up water
is drawn from the suction port 4, flows toward a discharge
port 5 through gaps between the blade portions, and is
uniformed by the plurality of twisted guide vanes 14 each of
which is long in length, as described previously.
The helical blade 10 is so formed that weight balance
is superior with respect to the drive shaft 2. Further, the
blade exists continuously over the predetermined length in
the direction along the drive shaft, different from the
conventional pump which has the plurality of blades only in
a single plane perpendicular to the drive shaft 2. Thus, it
is possible to increase the lift.
In the figure, the vertical oblique-flow pump 1 is
shown whose configuration is such that a portion of the
vertical oblique-flow pump 1 including the helical blade 10
and the guide vanes 14 of which casing 20 is swelled or
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bulged into the form of a bowl- or pot-like configuration.
However, the vertical pump 1 may be a vertical axial-flow
pump having no bowl portion and having a configuration in
which the casing 20 is straight as a whole.
Fig. 3 is a partially cross-sectional side elevational
view showing a principal portion of a lower end section of
the pump 1 illustrated in Fig. 1. Fig. 4 is a bottom view
of Fig. 3, showing the pump 1 having a pair or helical
blades 10 and 11.
Each of the helical blades 10 and 11 is manufactured
such that a sheet material is processed into a helical
configuration. As will be understood from Fig. 4, the
blades 10 and 11 are wound helically through 360~ about the
rotary drive shaft 2 of the pump 1 such that their phases
shift 180~ from each other so as to be symmetrical with
respect to the shaft. The blades 10 and 11 are mounted on
the hub 8 at their respective proximal end portions 30 and
30. Outer peripheral edge portions 32 and 32 opposite
respectively to the proximal end portions 30 and 30 are in
proximity with the inner surface of the casing 20. The
forward end portions 33 and 33 of the respective helical
blades 10 and 11 extend downwardly from the forward end
portion 9 of the hub 8, to thereby form wide suction ports 4
and 4. An interval of the alternate blade portions of the
two blades 10 and 11 servin~ as a flow passage is-adequately
widened so that cloths and solid matters included in the
sewage and the like pumped up can pass.
When the driv-e shaft 2 is rotated, the pumped water is
drawn simultaneously from the two suction ports 4 and 4
which are located in symmetrical relation to each other with
respect to the shaft, passes through gaps between the blade
portions, generates a flow in a single helical direct:ion,
flows into the two discharge ports 5 and 5 which are located
in symmetrical relation to each other with reference to the
shaft, and is uniformed by the plurality of twisted guide
vanes 14 which arc long in length, as described previously.
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As described ~bove, in a case where two helical blades
10 and 11 are provided in this manner, the blades are
arranged symmetrically with respect to the shaft, and the
suction ports and the discharge ports are also arranged in
symmetrical relation to each other. Thus, the pump is
brought to a pump ~xtremely superior in balance. Further,
in a case of a sin~le helical blade, assuming that a single
plane extending perpendicularly to the drive shaft 2 is
considered, energy is given to the water at a single
eccentric location, and energy cannot be applied equally, so
that volumetric ef-ficiency is bad. ~enerally, the delivery
or discharge quantity of the pump is in proportion to the
caliber or aperture of the pump. In a case of a single
helical blade, however, it is impossible to cover the whole
volume of the water for the reason discussed above.
Accordingly, if the aperture of the pump increases, the
discharge quantity does not increase in proportion thereto.
On the other hand, in a case of a pump having two helical
blades, energy is ,riven to water at two locations
symmetrical to each other with respect to the shaft,
simultaneously in every or all planes extending
perpendicularly to the drive shaft 2 so that the volumetric
efficiency becomes superior. As a result, it is possible to
raise the lift and enlarge the aperture of the pump in oder
to increase the discharge quantity. Tests have been
conducted with res]?ect to a vertical oblique-flow-pump
illustrated in Fig. 3. As a result, it has been known that
efficiency is superior 4 - 5% as compared with the
conventional oblique-flow pump.
Fig. 5 shows a case where three identical helical
blades 10, 11 and :L2 are mounted on the hub 8 in place of
the two helical blades of the pump illustrated in Fig. 3,
with phases shifted 120~ from each other. Also in this
case, the blades as well as the suction ports and the
discharge ports are dispersed equally similarly to the pump
illustrated in Fig. 3, so that the pump is brought to a pump
superior in balance and superior in volumetric efficiency.
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It is preferable that the number of provided helical
blades is decided depending upon a condition in which the
dimension of the c~sing 20 of the pump 1 and the flow of the
fluid within the p-ump are brought into uniformity, and other
design conditions. In this connection, Fig. 3 shows the
vertical oblique-flow pump 1 in which a portion including
the helical blades 10 and 11 and the guide vanes 14 of the
casing 20 are bulged in the form of a bowl or pot. However,
the pump may be brought to a vertical axial-flow pump in
which there is no bowl portion and which has a configuration
in which the entire casing 20 is straight.
INDUSTRIAL AP]'LICABILITY
As described above, since the pump having a single or
a plurality of helical blades, according to the invention,
can be made large in lift and large in discharge quantity,
there are produced advantages that a conventional relay
station for pumping up arranged in a case where the lift is
small can be omitted, and the like. Thus, it is possible to
utilize the pump widely in various industries.
Moreover, since the flow passage within the pump is
relatively wide and is a single direction in the direction
of the drive shaft, things or objects do not lodge. Thus,
the pump can also be utilized for pumping up of sewage or
the like containing articles such as a block of cloth or
papar which tends 1tO block conventional pumps.
