Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invention relates generally to pumps and rnore
particularly to an improved bearing arrangement for the drive
shaft of a submersible pumpO
Submersible electric pumps are frequently used to
pump well water and other fluids containing abrasive materials
such as sand and the like. Typically, the upper end of the
drive shaft of the pump is receivecL by a sleeve bearing which
allows the water to flow between it and the shaft for lubrication
purposes. However, the abrasive materials in the water can
cause undue wear on the shaft and bearing, particularly in newly
developed wells which tend to contain substantial amounts of
sand. Such damage to the components makes the bearing incapable
of maintaining the pump shaft in the proper alignment, resulting
in inefficiency of the pump or complete pump failure in some
cases.
A related problem arises when the pump operation is
stopped and the abrasive materials are allowed to settle down
into the pump head. The abrasives can then enter the bearing
from above and become wedged between the outside of the shaft
and the inside of the sleeve bearing. This causes binding of
the shaft and can result in failure of the pump to start at all.
It is thus apparent that a need exists for an
improved bearing arrangement which reduces the problems associa
ted with the pumping of fluids containing abrasive materials
such as sand and the like. It is the primary goal of the
present invention to meet that need.
According to the invention, there is provided in a
submersible pump having a housing with inlet and discharge ends
and a fluid flow passage between said ends, a rotary drive
shaft in the housing having an upper end, and an impeller
mounted on said shaft for rotation therewith to pump fluid
through said passage from the inlet encl to the discharge end,
the improvement comprising: a hollow sleeve bearing supported
on the housing and receiving the upper end of said shaft to
assist in maintaining the alignment thereof, said shaft fitting
loosely in said sleeve bearing to provide a clearance space
communicating with said flow passage to permit fluid flow
between said shaft and bearing for lubrication purposes;
and a filter element mounted in said sleeve bearing above 'che
upper end of said drive shaft, said filter element being
formed of a porous substance restricti.ng fluid flow through
saLdclearance space while permitting fluid flow therethrough
in sufficient quantity to lubricate the shaft and bearing,
said filter element substantially preventing abrasive materials
in the fluid such as sand and the like from passing downwardly
through said filter element into said clearance space.
In the accompanying drawing, which forms a part of
the specification and is to be read in conjunction therewith,
and in which like reference numerals are used to indicate like
parts in the various views:
Figure 1 is a fragmentary sectional view of a sub-
mersible electric pump which is equipped with a sleeve bearing
and filter element constructed according to a preferred
embodiment of the present invention; and
Figure 2 is an exploded perspective view of the sleeve
bearing and filte~ element shown in Figure 1.
Referring now to the drawi.ng in detail, numeral 10
generally designates a submersible electric pump which is
used to pump well water and other fluids that may contain
abrasive materials. Pump 10 is constructed conventionally
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for the most part and includes a suhmersible electric motor
(not shown) which is drlvingly coupled with the lower end of
a pump shaft 12. The lower end of shaft 12 is suitably
~ournalled near the bottom or intake end of the pump. The
pump housing i.ncludes the usual shell (not shown) which
extends between the
2a
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lower inlet end of the pump and an upper discharge head which
will subsequentl~ be described. Pump 10 is a multi-stage pump
having a plurality of impellers 14 carried on hubs 16 which are
fitted on shaft 12 and connected thereto by splines or the like
(not shown). Each impeller 14 has lower and upper shrouds 18
and 20 and a plurality of curved vanes 22 which direct fluid
outwardly withln the impeller through a generally radial passage
24 located between the vanes and shrouds 18 and 20. Each pass-
a~e 24 has an inlet 26 located adjacent to hub 16.
Underlying each impeller 14 is a diffuser disc 28
having an enlarged rim portion 30 on its outer periphery.
Upper and lower flanges 32 and 34 project from the rim of each
diffuser disc and interfit with grooves formed in an outer wall
portion 36 of a diffuser bowl 38 included in each stage of the
pump. Each diffuser bowl 38 has a disc portion 40 adjacent
hub 16. A small duct 42 is formed in each bowl 38 in
communication with the outlet end of the corresponding impeller
passage ~. A pair of curved vanes 44 are formed on the upper
surface of each disc 40 to direct fluid inwardly from duct 42
into a passage 46 which connects with the inlet 26 of the next
impeller passage.
The upper stage of the pump connects with a hollow
discharge head 48 having a flange 50 on its lower end which
interfits with the upper groove in wall 36 of the upper
diffuser bowl 38. The fluid passing through the pump is
thus directed upwardly from the upper passage 46 and through
the hollow interior of discharge head ~8. A hollow condui-t
52 is threaded to the top end of discharge head 48 to direct
the fluid upwardly.
The construction and operation of pump 10 are sub-
stantially the sarne as the pump shown in U.S. Patent No.
3r 477~ 384. However,
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the arrangement prov.L~ecl by the present lnventionis not limited
to any particular type of pump and may be used with any suit-
able submersible pump.
In accordance with the invention, the top end of
p~lmp shaft 12 is reduced in diameter as indi.cated at 12a and
is received wlthin a hollow sleeve bearing 54 mounted to an
internal l.ug 56 projecting from discharge head 48. Bearing
54 is closely fitted in an opening 5~ formed in lug 56 and
is suitably secured to the lug. An enlarged flange 54a is
formed on the lower end of bearing 5~ and is positioned
against the underside o lu~ 56 a slight distance above the
upper hub 16. Shaft portion 12a fits .rather loosely in
bearing 54 such that the fluid ~eing pumped is able to pass
upwardly between the outer diameter of shaft portion 12a
and the inside diameter of bearing 54. This fluid flow is
for the purpose of lubricating the shaft and bearing.
A filter 60 is press fitted into bearing 54 at the
top end thereof above the upper end of shaft portion 12a.
Filter 60 is a disc shaped element which is preferably formed
of a porous metal substa~ce such as sintered bronze. Although
any suitable material can be used, it is preferred that
filter 60 be constructed by combining selected metal powders
and compacting them under pressure and/or heat until they
become permanently bonded. This sintering technique results
in the formation of a permanent metal matrix having a
porosity in the range of approximately 35% to 65%, with
approximately 50% porosity being preferred in most applications
of the pump. The matrix can be formed such that it is capable
of filtering out particles of any desired size, depending on
the particle size expected to be encountered in a particular
application of t:he pump~ In a preferred form of the invention,
filter 60 is sintered bronze having a chemical composition of
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89% to 96% copper with the balance being t:in.
In operation of pump 10, shaft 12 is rot.ated by
the electric motor (not shown) to drive impellers 14. The
fluid drawn i.nto the lower or inlet end of the pump is
thereby pumped upwardly into the inlet 26 of each impeller,
outwardly through passage 24, upwardly through duct 42,
and then inwardly through passage ~l6 of each pump stage
until the fluid eventually passes t:hrough each stage of the
pump and reaches discharge head 48. The fluid is then
directed out of thepump through the discharge end which
connects with conduit 52.
Due to the loose fit of shaft portion 12a in sleeve
beariny 54, a small clearance space is provided between the
outside diameter of the shaft and the inside diameter of the
bearing. Consequently, fluid is able to flow through the
clearance space to adequately lubricate shaft 12 and bearing
54a The porosity of filter 60 is selected such that the fluid
is able to pass through the filter in sufficient quantity to
effect adequate lubrication of thepump components. At the
same time, the restriction to fluid flow provided by filter
60 reduces the fluid flow through bearing 54 in comparison to
that which would occur in the absence of a filter in the bearing.
Consequently, when the fluid contains significant quantities
of abrasive materials such as sand, the flow of abrasive
materials passing between the shaft and bearing is reduced,
resulting in reduced abrasion and wear on the shaft and
bearing~ It is thus apparent that filter 60 reduces the wear
and abrasion on the components while assuring that they are
adequately lubricated by the fluid.
When pump 10 is stopped, the abrasive materials in
discharge head 48 are allowed to settle downwardly into the
discharge head. ~Iowever, due to the presence of filter ~0,
the abrasive materials are prevented from entering bearing 54
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Erom the top. Consequently, filter 60 eliminates the prohlem
o~ abrasive materials settling into the top of bearing 54 ancl
becoming wedged between the outside diameter of shaft portion
12a and the inside diameter of bearing 54.
From the foregoing it will be seen that this
invention is one well adapted to attain all the ends and
objects hereinabove set forth together with other advantages
which are obvious and which are inherent to the structure.
It will be understood that certain Eeatures and
subcombinations are of utility and may be employed without
reference to other features and subcombinations. This is
contemplated by and is within the scope of the claims.
Since many possible embodiments may be made of the
invention without departing from the scope thereof, it is to
be understood that all matter herein set forth or shown in
the accompanying drawings is to be interpreted as illustrative
and not in a limiting sense.
