[0001] This invention relates to a bladed impellor for centrifugal pumps, of the type formed
by two coaxial superimposed discs of equal diameter, between which there is regularly
arranged a plurality of blades, the liquid entering axially to said blades and then
being discharged by centrifugal force between the edges of the discs.
[0002] Very many embodiments of bladed impellors for centrifugal pumps are already known,
outstanding among which are those described in Spanish utility models No. 205.690
and 282.527, both in the name of the present applicant, with all of them having a
serious drawback, consisting in that the central orifice of the impellor must carry
a key for drive purposes, representing either an assembly operation or a machining
operation, making the impellor substantially more expensive.
[0003] To cheapen the cost of the impellor and make its manufacture more profitable, the
impellor of the invention is characterized in that one of the discs is provided with
a large axial orifice and bears on the inner surface thereof fixedly attached blades,
while the other disc is provided with a central injection moulded hub, of a substantially
rigid material, having a central tubular orifice coaxial with that of the first disc
but of smaller diameter and provided internally with a key adapted for engagement
with a key slot of the drive shaft.
[0004] According to a further feature of the invention, the disc bearing the hub is provided
previously with a central orifice and several smaller orifices around the centre one,
the injection moulded material of the hub passing through said smaller orifices after
injection.
[0005] The accompanying drawings illustrate one embodiment of the impellor of the present
invention as a non-limitative example.
Figs. 1 and 2 are respective plan and sectional elevation views, respectively, of
the first disc;
Figs. 3 and 4 are respective views also in plan and sectional elevation, respectively,
of the second disc of the impellor according to the invention;
Figs. 5 and 6 illustrate two views also in plan and in sectional elevation, respectively,
of the assembled impellor; and
Fig. 7 is a plan view of the second disc before injection moulding of the hub.
[0006] In the drawings, the impellor may be seen to comprise two coaxial superimposed discs
1 and 2 of like diameter, between which a plurality of blades 3 are regularly disposed.
[0007] The liquid flows in axially to said blades through a large orifice 5 in the disc
1 and is then discharged by centrifugal force between the edges of the discs 1 and
2, through the openings 4.
[0008] The disc 1, apart from the said central orifice 5, is provided with the blades 3,
fixedly attached to the inner surface thereof.
[0009] In turn, the disc 2 is provided with a central injection moulded hub 6, of a substantially
rigid material, provided with a central tubular orifice 7 coaxial with the orifice
5 but having a smaller diameter than the latter.
[0010] The hub 6 is provided internally with a key 8 adapted to engage a key slot of the
drive shaft, not shown.
[0011] The disc 2 is provided initially with a central orifice 9, corresponding to the orifice
7 of the hub 6 and several smaller orifices 10 around the central one 9, so that the
injection moulded material of the hub 6 is disposed through said smaller orifices
10 after being injected, as may be seen in Fig. 6.
1.- Bladed impellor for centrifugal pumps, of the type formed by two coaxial superimposed
discs of like diameter between which there is regularly disposed a plurality of blades,
the liquid flowing in axially to said blades and being discharged thereafter by centrifugal
force between the edges of the disc, characterized in that one of the discs is provided
with a large axial orifice and bears the said blades fixedly attached to the inner
surface thereof, while the other disc is provided with a central injection moulded
hub of a substantially rigid material, provided with a central tubular orifice, coaxial
with that of the first disc, but of smaller diameter and provided internally with
a key adapted to engage a key slot of the drive shaft.
2.- Bladed impellor for centrifugal pumps, according to claim 1, characterized in
that the disc bearing the hub is provided previously with a central orifice and several
smaller orifices around the central one, the injection moulded material of the hub
passing through said smaller orifices after being injected.