U.S. patent number 3,719,436 [Application Number 05/074,398] was granted by the patent office on 1973-03-06 for axial flow pump.
This patent grant is currently assigned to The Gorman-Rupp Company. Invention is credited to Stanley B. McFarlin.
United States Patent |
3,719,436 |
McFarlin |
March 6, 1973 |
AXIAL FLOW PUMP
Abstract
An axial flow pump includes a housing supporting a tubular,
electric motor driven pump body for rotation about an axis, and a
plurality of impeller units detachably supported within the tubular
pump body. The impeller units are constructed to provide a
substantially unobstructed axial pumping passage through the pump
body and are removable from the pump body without requiring
disassembly of the pump body or the housing.
Inventors: |
McFarlin; Stanley B.
(Jeromesville, OH) |
Assignee: |
The Gorman-Rupp Company
(Cleveland, OH)
|
Family
ID: |
22119344 |
Appl.
No.: |
05/074,398 |
Filed: |
September 22, 1970 |
Current U.S.
Class: |
417/356 |
Current CPC
Class: |
F04D
13/0646 (20130101); H02K 7/14 (20130101) |
Current International
Class: |
H02K
7/14 (20060101); F04D 13/06 (20060101); F04b
035/04 () |
Field of
Search: |
;417/356 ;310/61
;415/72 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Freeh; William L.
Assistant Examiner: Winburn; John T.
Claims
What is claimed is:
1. A fluid pump having an inlet and a discharge and comprising:
a. a housing;
b. a hollow tubular body supported by said housing for rotation
about an axis, said body defining first and second end openings and
a flow passage extending therethrough along said axis between said
end openings;
c. drive means for rotating said body about said axis; and,
d. impeller means supported by said body for propelling fluid
through said flow passage defined by said tubular body;
e. said impeller means comprising at least an impeller detachably
connected to an internal peripheral portion of said body member and
axially removable from said body through one of said first or
second end openings of said body.
2. A pump as claimed in claim 1 wherein said pump body comprises a
hollow shaft, said impeller comprising a shroud member detachably
connected to said internal peripheral portion of said shaft for
rotation with said shaft about said axis, and at least an impeller
member in said passage supported solely by said shroud member at
the juncture of said shroud member and said impeller member, said
shroud member and said impeller member removable as a unit from
said shaft via one of said end openings.
3. A pump as claimed in claim 2 wherein said impeller member is
defined by a blade projecting toward said axis from said shroud
member, said blade terminating radially outwardly from said axis
whereby said passage is unobstructed along said axis.
4. A pump as claimed in claim 2 wherein said impeller member
comprises an auger defined by a helically formed sheet supported by
said shroud member at its edges and devoid of a central supporting
member.
5. A pump as claimed in claim 2 including a plurality of said
impellers each detachably connected to an internal peripheral
portion of said shaft at axially spaced locations along said
passage, each impeller removable from said passage through one of
said first or second openings.
6. A pump as claimed in claim 5 wherein the impeller members of
successive impellers have decreasing pitches proceeding along said
passage from one of said end openings toward said other end
opening.
7. A pump as claimed in claim 2 wherein said housing defines inlet
and discharge ports aligned with said flow passage, and said shroud
member has a smaller diametrical extent than the diametrical extent
of at least one of said inlet or discharge ports, said shroud
member removable from said housing through said at least one inlet
or discharge port.
8. A pump as claimed in claim 1 wherein said drive means for
rotating said body about said axis comprises an electric motor
having a stator in said housing and a rotor formed by said
body.
9. A pump as claimed in claim 8 and further including seal means
between said body and said housing at axially spaced locations,
said seal means, said body and said housing defining a chamber
surrounding said body, and further including fluid in said chamber,
said fluid circulating when said body rotates to transfer heat to
pumped fluid in said passage from said motor.
10. A pump as claimed in claim 9 wherein said housing comprises
first and second identical end cups each having an annular lip at
an outer periphery and an annular base at an inner periphery, said
annular lips engaging along the outer periphery of said housing and
a sleeve extending between said bases along an inner periphery of
said housing, and means for hermetically sealing said stator in
said housing between said end cups and said sleeve.
11. A pump as claimed in claim 10 wherein said housing further
includes first and second identical support members connected to
respective bases of said end caps, said support members associated
with bearings supporting said pump body, said housing being
symmetrical about the juncture of said lips.
12. A pump comprising:
a. an electric motor defined by a generally cylindrical stator
assembly and a rotor member supported for rotation about an axis
extending through said stator assembly;
b. a generally cylindrical pumping passage defined by said rotor
member, said pumping passage extending through said rotor member
along said axis and defining a first opening at one end of said
rotor member and a second opening at an opposite end of said rotor
member with pumped fluid passing through said passage via said end
openings;
c. impeller means in said pumping passage and disposed at least in
part between said first and second rotor member openings, said
impeller means being operative to create a flow of fluid through
said pumping passage via said openings when said rotor member is
rotated about said axis; and,
d. connecting means between said impeller means and said rotor
member for enabling removal and replacement of said impeller means
from said pumping passage through one of said rotor member
openings.
13. A pump as claimed in claim 12 wherein said impeller means
comprises impeller members projecting radially into said pumping
passage, said impeller members defining projecting tip portions
which are spaced radially outwardly from said axis.
14. A pump as claimed in claim 12 wherein said impeller means
comprises an auger defined by a helically formed sheet-like member,
said sheet-like member supported in said passage along side edges
thereof.
15. A pump as claimed in claim 12 wherein said connecting means
comprises at least a member between said impeller means and said
rotor member said at least one member being detachably connected to
at least one of said impeller means or rotor member.
16. A pump as claimed in claim 15 wherein said member of said
connecting means is detachably connected to said rotor member by an
adhesive material.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to pumps, and more
particularly to axial flow pumps.
2. The Prior Art
The prior art has proposed axial flow pumps in which impellers
forced liquid axially through a tubular rotatable pumping body. In
some prior art pumps, the tubular pump body carried an impeller at
one end so that the tubular body formed an inlet passageway for the
impeller. In other proposals, impellers were supported in the pump
body itself on central shafts or similar supports.
These proposals required nearly complete disassembly of the pump
body or the pump body housing in order to service or replace an
impeller. When these axial flow pumps were used to pump liquids
containing significant quantities of debris, such as in sewage,
they tended to clog because debris jammed against obstructions,
such as the impeller supporting shafts, in the flow path through
the pumps. Servicing often required the pumps to be torn down to
gain access to the debris jammed in the flow passages. The pumps
also had to be torn down in order to replace impellers which were
damaged and/or eroded by abrasive or chemically active materials in
the pumped liquid. Servicing such pumps was expensive, time
consuming, complicated and often unpleasant for the serviceman. At
least partly because of the foregoing problems, axial flow pumps
have not been widely commercialized, particularly when used to pump
liquids containing debris and/or abrasive particulate matter.
Electric motor driven centrifugal pumps having the motor windings
and pump mechanism in a common housing have been widely used. The
motor windings in these pumps were frequently hermetically sealed,
particularly where the pump was likely to be submerged. When the
motor windings were sealed, heat dissipation was retarded and the
motors tended to overheat.
It was proposed to dissipate this heat by transferring it to the
pumped liquid. In some proposals, the pump housings were cast with
flow passages in them for directing pumped liquid through the
housing close to the motor windings. These passageways were often
tortuous, thus tending to become clogged and/or eroded by particles
in the pumped fluid. Furthermore, the housing castings were
expensive and complex.
In some proposals, the motor windings were not sealed and heat was
dissipated from them by directing pumped liquid onto the windings.
These proposals could not be employed in circumstances where
abrasive materials were likely to be present in the pumped liquid
or where chemically active elements might be pumped, since the
motors would be damaged.
Electric motor driven pumps were sometimes damaged by rotating the
impellers opposite to the designed pumping direction. Many pumps of
this type had impellers which were screwed onto their drive shafts.
If a drive motor was incorrectly wired, the impeller tended to
screw off of its shaft resulting in damage to the pump.
In summary, prior art axial flow pumps have been subject to
clogging or erosion due to debris and particulate matter in the
pumped liquid; have been difficult to service when clogged or when
impeller needed repair; were either subject to overheating due to
inadequate heat dissipation from electric drive motors or employed
complex, expensive motor cooling arrangements; and were sometimes
subject to damage when the impellers were rotated reversely from
their intended direction of rotation.
SUMMARY OF THE INVENTION
The present invention provides a new and improved axial flow pump
characterized by a simple and inexpensive construction which
enables impeller servicing or replacement without disassembly of
the pump. The new pump also provides for heat dissipation from an
electric drive motor to the pump effluent without routing the
effluent through housing passageways and without exposing the motor
windings to the pumped liquid.
The new pump is particularly useful in applications requiring large
flow rates of pumped liquid at moderate pressures, is adapted to
operate submerged and can readily pump liquids which may contain
substantial amounts of debris and/or particulate abrasive
material.
In a preferred embodiment, the new pump includes a housing assembly
defining a pump inlet port and a pump discharge port and a
rotatable pump body supported in the housing. Impeller units are
detachably connected to the pump body and can be removed and
replaced through the inlet or discharge ports without tearing down
the housing or the pump body.
In the preferred embodiment, the pump is driven by an induction
motor having an encapsulated stator in the housing. The housing
provides an impervious container for the stator and the pump can be
submerged without exposing the stator to the liquid. The pump body
forms the motor rotor and provides an axial pumping passage in
which the impeller members of the pump are mounted.
The construction of the pump body and housing promotes heat
dissipation from the stator and rotor windings without exposing the
windings to the pumped liquid which otherwise might damage them. In
the preferred construction, the pump body is supported in the
housing by bearings which are spaced axially apart. Seal assemblies
are disposed between the housing and the pump body axially
outwardly of the bearings. A chamber is thus formed between the
pump body and the housing. The chamber contains a suitable liquid
such as transformer oil which, when the motor is operating,
circulates in the chamber. The oil picks up heat from the rotor
windings and from the chamber walls adjacent the stator windings
and transfers the heat to the liquid flowing through the pump via
the pump body. The circulating oil also lubricates the
bearings.
The impeller units are detachably mounted in the pumping passage.
Each impeller unit is removable from the pump body through an
adjacent inlet or discharge housing port without requiring
disassembly of the housing or the pump body. In one preferred
embodiment, the impeller units include a cylindrical shroud member
which is detachably connected to the pump body at its outer
periphery and impeller blades integral with the shroud member.
The shroud members may be attached in the pump body by commercially
available adhesive materials capable of transmitting sufficient
torque for pumping yet readily releasing the impeller when desired.
This mode of connection enables the pump to operate in either
direction of rotation to reverse the flow direction of the pumped
liquid, as might be required in a pipe line installation. Other
modes of connection such as interengaging splines or screw threads
may be employed.
The pumping passage of the new pump is substantially unobstructed
by impeller or rotor supporting parts so that debris in the pumped
liquid does not tend to clog the pump. If the pump does clog, the
unobstructed passage permits dislodgment of the offending debris
without requiring disassembly of the pump.
In one embodiment, the impeller blades extend inwardly from the
inner periphery of the shroud member toward the axis of rotation of
the pump body. The blades terminate short of the center of the axis
of rotation and are spaced from each other at their tips so that
the pump body is open along its axis of rotation.
In another preferred form, the impeller blades are formed by an
auger-like member which is supported solely by the surrounding
shroud member and has no central supporting body or shaft.
Several impeller units may be serially supported in the pump body.
These impeller members can be constructed to provide for
compounding if desired by providing impeller blades having varying
pitches proceeding through the pump body.
A principal object of the present invention is the provision of a
new and improved axial flow pump which is of simple, inexpensive
construction, employs a substantially unobstructed pumping passage
to minimize clogging and which, if clogged, is easily cleared
without requiring disassembly.
Another object of the present invention is the provision of a new
and improved axial flow pump having one or more impeller units
which are detachably connected to a rotatable pump body and which
impeller units can be removed and replaced through a housing port
without requiring disassembly of either the pump housing or the
rotatable pump body.
Still another object of the invention is the provision of a new and
improved axial flow pump driven by an electric motor which is
hermetically sealed and wherein heat from the motor is transferred
to the pumped liquid through a heat transfer medium contained in a
chamber between the pump body and the housing.
Other objects and advantages of the present invention will become
apparent from the following detailed description made with
reference to the accompanying drawings which form a part of the
specification.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross sectional view of a pump embodying the present
invention;
FIG. 2 is an end view of the pump of FIG. 1 seen from the plane
indicated by the line 2--2 of FIG. 1;
FIG. 3 is a fragmentary cross sectional view of another preferred
embodiment of the new pump seen approximately from the line 3--3 of
FIG. 4; and,
FIG. 4 is an end view seen from the left end of FIG. 3.
DESCRIPTION OF PREFERRED EMBODIMENTS
One preferred embodiment of an axial flow rotary pump 10
constructed according to the present invention is illustrated in
FIGS. 1 and 2. The pump 10 is usable in applications where large
flow rates of pumped liquid are required at moderate pressures. The
pump can be submerged and is particularly suited to pump sewage or
liquid which may contain substantial amounts of debris and/or
abrasive particulate matter, etc. The pump 10 includes a housing
assembly 12 defining an inlet port 14 and a discharge port 16. A
pump body 18 is supported by the housing assembly 12 for rotation
about an axis 19. The pump body 18 carries impeller units 20 which
rotate with the pump body to propel liquid through the pump along
the axis 19. An alternating current induction motor 22 drives the
pump body.
The housing 12 is a simple, inexpensive assembly which supports the
pump body 18 while providing a hermetically sealed container for
the stator of the motor 22. The housing 12 includes a pair of
mating identical end cup members 24, 26; a thin cylindrical sleeve
27 connected between the end cup members along the inner periphery
of the housing; and bearing support members 28, 30 which are
supported at opposite axial ends of the end cup members 24, 26,
respectively.
The mating end cups 24, 26 and the sleeve 27 form an annular
enclosure in which the stator 32 of the motor 22 is hermetically
sealed. Referring to FIG. 1, each of the end cup members is a cast
body having an annular axially facing lip 33 at its outer periphery
and a base 34 having a cylindrical opening 34a extending through
it. Each end cup 24, 26 has a wall portion 35 extending radially
from the base 34. The wall 35 has a bossed area 35a surrounding an
opening 36.
The stator 32 is of conventional construction including a stack of
laminations 32a and stator windings 32b. The stator 32 is
encapsulated in a mass 37 of potting compound, which may be any
suitable epoxy. The potting compound completely fills the enclosure
defined by the housing. A power cable 38 for the stator windings
extends through the opening 36 in the end cup member 26. The
opening 36 in the end cup member 24 is sealed closed by the potting
compound.
The method of assembling the end cups 24, 26, sleeve 27 and the
stator 32 is simple and requires minimal labor. The end cup member
24 is placed on a suitable horizontal surface with its lip 33
facing upwardly. The opening 36 is plugged and the sleeve 27 is
pressed into place along the inner periphery of the base 34. A
small shoulder 39 may be provided in the base for receiving the
sleeve 27, if desired. Uncured potting compound is then poured into
the end cup member 24. The stack of laminations 32a has an outer
periphery which fits snugly against the inner periphery of the end
cups, and the stator 32 is pressed into the end cup member 24. The
end cup member 26 is then placed over the sleeve 27 and the end cup
member 24, and pressed onto the stator 32 until the cup lips 33
mate and the sleeve 27 is engaged by the shoulder 39 in the end cup
26. The power cable 38 is pulled through the opening 36 in the end
cup 26 and the remaining space in the housing is filled with
potting compound which is introduced through the opening 36 around
the power cable 38.
The housing may be placed under vacuum pressure to assure complete
filling with potting compound after which the compound is
cured.
The end cups 24, 26 are maintained in mating engagement by the
cured potting compound; however the lips 33 can be welded or
cemented together at their juncture if desired.
The support members 28, 30 provide bearing supports for the pump
body 18 and also enable connection of accessory components to the
pump. The support members 28, 30 are identical and each includes a
body 40 having a flange 42 engaging the base 34 of the adjacent
housing end cup. The base 34 of each end cup carries a plurality of
projecting studs 43 each having a threaded end extending through a
bore in the flange 42. The support members are each bolted to the
housing 12 by nuts which are threaded on the studs 43. The central
openings through the bodies 40 of the support members 28, 30 define
the housing inlet and discharge ports 14, 16, respectively.
The body 40 projects into the adjacent end cup base 34 and a
suitable seal arrangement 46 is disposed between them. The
projecting end of the body 40 defines an annular bearing seat 47. A
bearing assembly 48 has its outer race engaged on the seat 47. The
pump body 18 is journalled in the bearing assemblies 48.
Various accessory components can be detachably connected to the
support members 28, 30. The bodies 40 are each provided with tapped
holes arranged about the axis of rotation of the pump body 18 so
that parts can be screwed onto the bodies 40 and thus attached to
the housing. In the embodiment illustrated in FIG. 1, a pipe
coupling member 49 is attached to the support member 30. The
coupling member is provided with internal pipe threads into which a
pump discharge pipe (not shown) can be screwed. The pipe coupling
member is illustrated by way of example and accordingly is shown in
broken lines.
The support member 28 at the opposite end of the pump 10 has a pair
of identical bracket-like legs 50, 52 (FIG. 2) attached to it. The
legs 50, 52 are utilized for handling the pump prior to
installation. Where the pump is installed in a submerged location,
the legs support the pump in an upright position with the inlet
port 14 spaced from the supporting surface so that flow through the
inlet is not restricted.
The pump body 18 forms the rotor of the motor 22 and provides an
axial pumping passage in which the impeller units are supported.
The body 18 includes a hollow rotatable shaft 64 having an axial
bore 65 extending through it along the axis 19. The rotor assembly
66 of the motor 22 is affixed on the external periphery of the
shaft 64. The rotor assembly is conventional and includes a stack
of laminations 66a fixed to the shaft and rotor windings 66b.
The shaft 64 is rotatably supported by the bearing assemblies 48
which are positioned at opposite axial ends of the rotor 66. The
pump body 18 is freely rotatable with respect to the housing 12 and
when the motor 22 is energized, the pump body 18 is driven by the
motor. The motor 22 is reversible so that the pump body 18 can be
driven in either rotational direction to reverse the direction of
flow of the pumped liquid.
The construction of the pump body 18 and the housing 12 promotes
heat dissipation from the stator and rotor windings without
exposing the windings to pumped liquid which might otherwise damage
them. More particularly a sealed annular chamber generally
designated by the reference character 70 is formed between the pump
body and the housing. The chamber 70 contains a fluid which
circulates in the chamber when the motor is operating and carries
heat from the motor windings to the pump body which is cooled by
the pumped liquid. The axial ends of the chamber 70 are formed by
seal assemblies 74, 76. As is best seen in FIG. 1, the seal
assemblies 74, 76 are each supported between the housing 12 and the
pump body 18 axially outwardly of the adjacent respective bearing
assembly 48. The seal assemblies 74, 76 may be of any suitable
construction but are schematically shown as including a stationary
sealing ring 77 which is sealingly engaged with a shoulder 78 on
the body 40, and a rotatable sealing ring 79 which is sealingly
engaged with the shaft 64. The adjacent faces of the sealing rings
77, 79 are engaged to form a running seal between the housing 12
and the pump body 18.
The chamber 70 is preferably filled with transformer oil which
dissipates heat and lubricates the bearings and seal faces. When
the motor 22 is energized, the oil in the chamber circulates
vigorously in the chamber. Heat from the stator 32 is conducted to
the oil through the sleeve 27. The rotor windings dissipate heat
directly to the oil. The shaft 64 has a relatively small wall
thickness and provides a heat sink from which heat is transferred
from the oil in the chamber 70 to the pumped liquid.
The impeller units 20 are detachably mounted in the pumping passage
defined by the bore 65 and each impeller unit is removable and
replacable through the adjacent inlet or discharge port without
loosening or removing portions of the housing assembly 12 or any
part of the pump body 18. As is shown in FIG. 1, two impeller units
20a, 20b are mounted in the shaft 64 at opposite axial ends. The
impeller units 20a, 20b are identical and accordingly only the
impeller unit 20a is described in detail. The unit 20a includes a
cylindrical shroud member 80 which is seated in the bore 65 at the
inlet end of the shaft 64. Four impeller blades 82 are integral
with the shroud member and project radially inwardly from the
shroud member towards axis 19. The blades terminate short of the
axis 19 and the blade tips are spaced from each other so that the
axis of rotation 19 extends uninterrupted through the pumping
passage. The blades 82 are supported solely at their juncture with
the shroud member 80.
The shroud member 80 has a radially outwardly extending shoulder 84
which seats against the end of the annular shaft 64. The shroud
member is detachably connected to the shaft along its external
periphery by an adhesive material which when hardened transmits
sufficient torque to enable effective pumping of the liquid by the
impeller but which frees the shroud member for removal when
desired. These adhesives permit reversing the direction of rotation
of the pump body without loosening the impeller units. For example,
such adhesives can be broken by sharply rapping the shroud member
at various locations about its periphery. Other fastening devices
can be employed to maintain the impellers in place on the interior
of the shaft such as splines or screw threads, etc.
FIGS. 3 and 4 show a pump 10 employing alternate forms of impeller
units. Three alternate impeller units 120, 122 and 124 are
detachably fixed in the shaft 64. The impeller units 120, 124 at
opposite ends of the shaft 64 each include identical shroud members
126, 128, respectively. These shroud members each have an annular
radially outwardly extending shoulder 130 which engages the annular
end of the shaft. The shroud members 126, 128 are suitably
connected to the shaft in the manner described above.
The impeller member 134 in the impeller unit 120 is an auger-like
element formed by a sheet of material which is helically twisted
and attached to the shroud member 124 at its edges. The auger-like
member has a uniform cross sectional thickness and has no central
supporting shaft or the like. The sole support for the auger member
is formed by the surrounding shroud member.
The impeller units of FIGS. 3 and 4 have a decreasing pitch, or
bite, proceeding through the pump from the inlet port to the outlet
port. This produces a staging or compounding effect which increases
the pump discharge pressure. The auger-like impeller member 136 of
the impeller unit 124 is substantially the same as the auger 134
except that its pitch or lead is smaller.
The central impeller unit 122 is spaced from the impeller units
120, 124 by axial spacers 138. The unit 122 includes a cylindrical
shroud member 140 and an auger-like impeller member 142. The shroud
member 140 is suitably fixed to the shaft 64. The impeller member
142 is substantially the same as the impellers of the units 120,
124 except that its lead is slightly less than that of the impeller
134. The impeller unit 122 is removable from either end of the
pump.
Since the auger-like impellers of the units 120, 122, 124 have no
central supporting shafts or equivalent central supports, the pump
passage is relatively unobstructed. Hence, debris in the pumped
liquid does not tend to hang up in the pump passage. The
unobstructed pumping passage is readily accessible for cleaning out
without disassembling the pump if the passage does become clogged
by debris since the debris is easily dislodged by a cleaning tool
inserted through either the inlet port or the discharge port.
It can now be seen that a new and improved axial flow pump has been
provided and that the objects enumerated and others have been
accomplished. Although two preferred constructions have been
illustrated and described in considerable detail, the present
invention is not to be considered limited to the precise
constructions shown. It is intended to cover all adaptations,
modifications and uses of the invention which come within the scope
of the appended claims.
* * * * *