U.S. patent number RE32,027 [Application Number 06/546,420] was granted by the patent office on 1985-11-12 for wet pick-up vacuum unit motor bearing air seal.
This patent grant is currently assigned to Ametek, Inc.. Invention is credited to Robert L. Hyatt, Norbert H. Niessner.
United States Patent |
RE32,027 |
Hyatt , et al. |
November 12, 1985 |
Wet pick-up vacuum unit motor bearing air seal
Abstract
A wet pick-up type vacuum motor fan unit with a separately
ventilated motor section and a motor end bracket serving also as a
support for, and part of a discharge end housing wall for, the
working air fan section, has on the bracket fanward face a
centrally apertured metal disk plate defining a flow space or path
for bearing sealing air flow from ambient air inlets external of
the motor section to a central discharge into the inlet eye of an
auxiliary fan clamped on the shaft back-to-back with a larger
diameter working air centrifugal fan adjacent the end bracket. A
stamped shield cup jointly clamped on the shaft with the fans
extends out of the auxiliary fan inlet eye into the disk central
aperture, surrounding the shaft bearing socket of the bracket and
being spaced from the disk aperture edge to afford a sealing air
outlet from said space into the auxiliary fan inlet eye; whereby
the disk plate and shield afford mechanical shielding, while air,
discharging to and from the auxiliary fan, provides air shielding
of the shaft and bearing area from working air entrained foam and
moisture.
Inventors: |
Hyatt; Robert L. (Tallmadge,
OH), Niessner; Norbert H. (Kent, OH) |
Assignee: |
Ametek, Inc. (Kent,
OH)
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Family
ID: |
27068243 |
Appl.
No.: |
06/546,420 |
Filed: |
October 28, 1983 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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145667 |
May 1, 1980 |
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Reissue of: |
799241 |
May 23, 1977 |
04088424 |
May 9, 1978 |
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Current U.S.
Class: |
417/368; 15/413;
277/424; 417/373; 417/423.2 |
Current CPC
Class: |
F04D
25/082 (20130101); A47L 5/22 (20130101) |
Current International
Class: |
F04D
25/08 (20060101); A47L 5/22 (20060101); F04D
25/02 (20060101); F04B 039/06 (); A47L
009/22 () |
Field of
Search: |
;15/412,413
;417/368,373,423R,423A,424 ;277/3,12,133,134,226 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2003905 |
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Jan 1970 |
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DE |
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2341233 |
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Feb 1974 |
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DE |
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Primary Examiner: Casaregola; Louis J.
Attorney, Agent or Firm: Oldham, Oldham & Weber Co.
Parent Case Text
.Iadd.This is a continuation of application Ser. No. 145,667, dated
May 1, 1980, now abandoned, which is in turn a reissue application
of U.S. Pat. No. 4,088,424, issued May 9, 1978. .Iaddend.
Claims
What we claim is:
1. In a wet pick-up type vacuum cleaner fan unit with a cleaning
working air centrifugal fan impeller mounted on a fan shaft
supported in a lubricated bearing received in a central socket of a
fan housing end wall,
said impeller peripherally discharging to a working air outlet of
the housing located adjacent to said end wall,
the improvement comprising:
a centrally apertured disk plate circumferentially engaged and
sealed upon and spaced from the fanward inner face of the said end
wall;
a plurality of angularly spaced auxiliary or sealing air inlets
through said wall from the exterior to an air flow space defined
between the disk and end wall face;
an auxiliary centrifugal fan of smaller diameter than, and in
back-to-back relation with, said working fan impeller,
said auxiliary fan being clamped on said shaft with its inlet eye
facing the central aperture of said disk to receive auxiliary air
therefrom;
a shield cup received with circumferential spacing in the auxiliary
fan inlet eye and
having a centrally apertured flat bottom conjointly clamped with
said fans on said shaft, and
extending through the central aperture of the disk to define with
the edge thereof a discharge outlet from said flow space into the
auxiliary fan eye;
whereby said shield and disk provide structural screening around
said bearing socket and shaft, and
said auxiliary fan, shield and disk further moving auxiliary
screening and sealing air axially exterior to the socket and on out
to a common discharge of said back-to-back auxiliary and working
air fans to prevent foam and working air entrained detergent from
approaching said bearing.
2. A wet pick-up type vacuum cleaner fan unit improvement as
described in claim 1, wherein
the bearing-receiving central socket projects from said end wall
toward the adjacent but axially spaced working air fan; and said
shield cup has its circumferential wall surrounding the socket
projection with running clearance.
3. A wet pick-up type vacuum cleaner fan unit improvement as
described in claim 2, wherein
said socket projects through the central aperture of said disk
plate into the central inlet eye of the auxiliary fan.
4. A wet pick-up type vacuum cleaner fan unit improvement as
described in claim 3, wherein
the inner face of said end wall is provided with a circular bead
concentric with the shaft and located radially outward of said air
inlets;
said disk having a cylindrical short rim flange fitted over said
bead thereby to secure and seal the disk to said end wall.
5. A wet pick-up type vacuum cleaner fan unit improvement as
described in claim 1, wherein
said end wall is an end bracket comprising part of a motor housing
of an electric motor incorporated in said unit as a motor-fan unit;
and
the motor housing is ventilated by a cooling air stream separate
from the working air stream. .Iadd.
6. In a wet pick-up type vacuum cleaner fan unit in which the
working air (by which cleaning is performed) is driven by a working
air fan, said fan is mounted on a fan shaft journaled in a bearing
supported by a fan housing end wall which extends transversely of
said shaft, said fan discharging, through at least one outlet of
the housing, the working air which is drawn by said fan through an
inlet to said housing, the improvement comprising:
a baffle plate having a substantially central aperture through
which said shaft extends into said housing, said plate being in a
substantially peripheral engagement with the inner face of said end
wall but elsewhere spaced therefrom in the direction of said
working air fan to provide air flow space between said wall and
plate;
at least one auxiliary sealing air inlet leading through said wall
into said air flow space, any such auxiliary air inlet being spaced
from said shaft and any such outlet;
an auxiliary fan mounted on said shaft between said working air fan
and said baffle plate, said fan having its inlet eye facing the
aperture of said baffle plate to receive sealing air therefrom;
and
means having an outer surface substantially concentric with said
shaft and which is partly located within, but radially inwardly
spaced from, the eye of said auxiliary fan, said means and said
fans being mounted on said shaft for rotation therewith, said means
extending axially from said auxiliary fan through the aperture of
said baffle plate at least as fan as said bearing, the surface of
said means where it passes through the aperture of said baffle
plate being peripherally spaced therefrom to provide a
substantially annular opening for auxiliary sealing air entering
and flowing in said air flow space toward said shaft in order to
pass axially through said annular opening into the auxiliary fan
eye and thence radially outwardly to a common discharge of air from
said auxiliary and working air fans, such passage of sealing air
axially through said annular opening thereby inhibiting the
approach to said bearing of foam and liquid entrained in said
working air. .Iaddend. .Iadd.7. A wet pick-up type vacuum cleaner
fan unit improvement as defined in claim 6, wherein said bearing
support projects inwardly from said end wall toward, but is axially
spaced from, the said working air fan; said means having an outer
surface substantially concentric with said shaft is a shield cup;
and the rim of said shield cup surrounds the projection of the
bearing support and extends to the inner face of said end wall with
a running clearance. .Iaddend. .Iadd.8. A wet pick-up type vacuum
cleaner fan unit improvement as defined in claim 7, wherein said
bearing support projects through the aperture of said baffle plate
and at least partly into the central inlet
eye of the auxiliary fan. .Iaddend. .Iadd.9. A wet pick-up type
vacuum cleaner fan unit improvement as defined in claim 8, wherein
the inner face of said end wall is provided with a peripheral
projection which is substantially concentric with the shaft and
located, with respect to said shaft, outwardly of said air inlets;
said baffle plate has a rim flange fitted over said projection
thereby to secure and seal the baffle plate to said end wall.
.Iaddend. .Iadd.10. A wet pick-up type vacuum cleaner fan unit
improvement as defined in claim 6, wherein said fan housing end
wall is also the end bracket of a separate housing for an electric
motor having an armature shaft which is extended through said
bearing to serve as the said fan shaft and any auxiliary sealing
air inlet is located exteriorly of the balance of the portion of
the unit which serves as the said housing for said motor, said
motor housing having openings therein for the inlet and outlet of
air for cooling said motor, whereby the motor-cooling air stream is
separate from the working and cooling air streams. .Iaddend.
.Iadd.11. In a wet pick-up type vacuum cleaner fan unit comprising
a motor, means for moving cooling air past said motor, a housing
for said motor, said motor housing having at least one inlet and at
least one outlet for said motor cooling air, a fan housing, an end
wall for said fan housing segregating said fan housing from said
motor, motor housing, and any inlet or outlet thereof for
motor-cooling air, a rotatable fan shaft extending through said end
wall into said fan housing, a bearing which is supported in said
end wall and in which said shaft is journaled, said shaft
rotatingly connected to said motor, said fan housing having at
least one inlet and one outlet for working air by which cleaning is
performed, the improvement comprising:
at least one auxiliary sealing air inlet extending through said
wall, such auxiliary air inlet being spaced from said shaft and any
outlet for working air,
baffle plate means mounted on the side of said wall within said fan
housing and having an aperture through which said shaft extends as
it enters said housing, said baffle plate means extending from any
auxiliary air inlet to a position adjacent said shaft to define an
air flow space extending from any said auxiliary air inlet to and
around said shaft, the periphery of said shaft and any means
mounted thereon which also extends through and is spaced from said
aperture defining, when said shaft is rotated, the inner periphery
of an annular opening from said air flow space into said housing
and the periphery of said aperture defining the outer periphery of
said annular opening, and
fan means mounted on said shaft, forcing said working air through
said fan housing, and presenting toward said annular opening a fan
eye whereby, when said shaft is rotated, auxiliary sealing air is
drawn through said auxiliary air inlet, air flow space, and axially
through said annular opening into said fan eye for discharge with
the working air through a working air outlet of said housing,
whereby passage of auxiliary air through said annular opening
inhibits the approach to said bearing, during rotation of said
shaft, of foam or liquid entrained in said working air, and wherein
said auxiliary sealing air is exclusive of any cooling air moving
past said motor. .Iaddend.
Description
Generally in modern domestic and commercial electric vacuum
cleaners or sweepers, a fan-driving electric motor and a
centrifugal fan or fans, as suction fan means, for moving the
working air or cleaning air through the cleaner, are incorporated
into a motor-fan unit. The motor fan unit is intended as a unit to
be assembled into or removable from the overall vacuum cleaner
structure which further provides a dirt filter and receptacle, or,
in wet pick-up types, a liquid receiver tank.
In wet pick-up floor or carpet cleaner equipment, especially the
jet hot water extractor carpet cleaners, which have come into
common use, and also in floor scrubbers where a vacuum pick-up of
residual or rinse water is used, air-entrained water and dirt are
separated from the working air, i.e., suction cleaning or transport
air, before the working air stream reaches the suction fans of the
apparatus, the separated liquid being either continually drained or
withdrawn from the apparatus, or retained in a collection tank.
Now especially in operating jet hot water extractor carpet
cleaners, there is applied to the carpet a water and detergent
solution, which of course is ultimately to be picked up and sucked
into the apparatus. By ordinary practice a "high foam" detergent is
not used in such cleaning methods, and usually there is no
troublesome foam generation or accumulation in the liquid or liquid
collection tank of the cleaner apparatus. However, if the operator
cleans a carpet which in fact had been previously cleaned with a
high foam detergent or shampoo, or inadvertently uses a high foam
detergent in his own cleaning operation, a considerable volume of
foam may be generated which finds its way into the suction
fans.
Though foam-suppressant compositions are available, and when a foam
problem is present or probable, the cleaner operator is expected to
use such a composition, especially in the liquid collection tank of
a jet hot water extraction cleaner, the suppressant may be omitted
or the problem may not be recognized in time. Hence by accident,
and not by intent, foam or foam-generating liquid may pass into or
through the suction fans of the cleaner. Thus detergent-carrying
liquid or foam may find its way in part to the adjacent fan shaft
bearing, from which it leaches out the lubricant with consequent
and often quite rapid bearing damage.
When foam enters or is generated in the fan system, rather than
leaving the fan housing cleanly at its normal working air discharge
region, at least in part it may be caught and churned between the
last fan and the adjacent bearing-supporting housing wall, in some
instances the churning action expanding foams to a much larger
volume; whence some part of the foam is then moved inwardly toward
the shaft region and there past the ordinarily simple mechanical
bearing seals. Very few occurrences of this sort are needed to
result in a bearing lubricant loss to such extent that rapid
bearing failure results.
By the present invention, to the final or working air discharging
centrifugal fan there is clamped in back-to-back relation a smaller
diameter auxiliary centrifugal fan to the central inlet eye of
which there is introduced along the bearing and shaft region what
may be termed "shielding" or "auxiliary" clean air. The auxiliary
fan then discharges the "auxiliary" air circumferentially for
sweeping foam, from the region between the fan housing wall and
back of the working air fan, towards the working air outlet.
Further, a flat-bottomed cup-shaped rotary baffle or seal shield is
commonly clamped on the shaft with, and in the inlet eye of, the
auxiliary fan, thus surrounding the shaft portion leaving the
adjacent bearing; in the case of a motor fan unit, extending
towards the fanward end bracket face, also to surround a projecting
bearing socket formation thereof. This affords further protection
of the bearing region, especially where as in the preferred form a
centrally apertured disk plate or baffle is secured on the fanward
side of the fan housing end wall, i.e., the fanward end bracket
face of a motor fan unit, to define an auxiliary or clean air flow
space extending from angularly spaced fresh air inlets radially
inward, towards the bearing region, to the central aperture as an
annular outlet to the auxiliary fan inlet eye.
By this further somewhat elaborate structure, for the clean air
flow, there is provided a further air and mechanical shield against
foam or liquid movement to the bearing region, due to any minor
recirculation of air from the auxiliary fan peripheral outlet to
its central inlet, even under conditions of extreme foam
loading.
The general object of the present invention is to provide, for wet
pick-up type vacuum sweepers, cleaners and the like, a suction fan
and bearing system including an improved safe-guard against foam or
detergent reaching the fan shaft bearing region.
A further object is to provide, in an electric motor vacuum fan
unit for wet pick-up type vacuum sweepers, cleaners and the like, a
suction fan and bearing system including an improved safe-guard
against foam or detergent reaching the fanward end bearing region
of the motor and bracket.
A still further and more particular object of the present invention
is to provide an electric motor vacuum fan unit of the character
described, including an improved air seal for the bearing, whereby
foam and detergent entrained in working air .[.is.]..Iadd.are
.Iaddend.prevented from gaining access to the fanward end bearing
of the motor, there to leach out lubricant and hence to result in
premature bearing failure.
Other objects and advantages will appear from the following
description and the drawing which shows an electric motor vacuum
fan unit generally of a type commonly used for vacuum sweepers and
as well cleaners of the wet pick-up type, wherein the unit is shown
partially in elevation and partially in longitudinal axial
section.
The motor-fan unit U shown in the drawing has a general
organization of known type being comprised of a separately
ventilated motor section M and a vacuum fan section F, wherein
working air moving centrifugal fans 32 and 34 are clamped directly
on the motor rotor shaft T projecting from the motor section into
the fan section housing.
In the motor section M, as the primary motor housing or stator
structure, the left motor end bracket 11 and the right or fanward
motor end bracket 12 are secured in engagement with opposite ends
of a wound stator or field core structure S by field clamp bolts
13, extending through 11 and threaded into 12. The rotor R is
supported to rotate within the field and stator structure by the
shaft T with projecting right and left ends extending through
appropriate bearing structures 15, 16 received in inwardly facing
bearing sockets 17, 18; the rotor here being a commutating armature
for which appropriate brush rigging, as indicated by the brush B,
is mounted on the motor or inward face of the fanward end bracket
12.
Though series universal motors are commonly used, the invention, of
course, is applicable to units with other motor sections of any
appropriate electrical design, and also to units with mechanical
variations; for example, brushing rigging could be supported on the
left end bracket.
A punched metal band 20 is wrapped around annular shallow
flat-bottomed receiving formations 11n and 12n on the end bracket
members with its ends secured to each other, either permanently or
in a readily removable manner, to form a motor housing
circumferential closure, which is appropriately punched with air
outlet apertures, particularly as at 20a for motor ventilating air
exhausting over the commutator and brush region. By axial flow
ventilation fan 22 secured on the left outboard end of the shaft T,
that air is drawn in through numerous cooling air inlet apertures
in the flat-ended, flange-rimmed cup-shaped ventilating fan cover
23, passing through apertures in the end bracket 11, and then;
through the length of the motor section, especially between rotor
and stator structure, for effective motor cooling.
In addition to serving as an end bracket for the motor as such
providing the motor right end bearing socket 18, and providing
support for the brushes, the member 12 first provides the inner end
wall for the fan housing structure, generally indicated at H, and a
rightwardly projecting rim 12r having a slight rabbetted annular
rim portion for receiving a cup-shaped element as part of the fan
housing H. Here, as shown further in the circumferential rim region
of member 12, the particular form of fan housing and discharge
further provides a scroll type expanding air outlet path including
a channel 24 inward of the rim portion 12r, which is open axially
to the right to receive air discharging from the periphery of the
adjacent suction fan. The channel has a flow area continually
increasing by increase in longitudinal, i.e., axial depth, as the
channel approaches an outlet at discharge connection flange 24a
integral with member 12.
The channel 24 is defined between an inner annular face of the rim
portion 12r and a minor channel wall surface continued to the left
from an annular bead 25. The inner circumferential wall of channel
24, hence bead 25, is about even with the outer, i.e., discharge,
periphery of the second stage impeller 32.
Bead 25 is concentric with the shaft and projects from a main face
of 12 to the right to sealingly receive and support the short
axially flanged rim of a centrally apertured disk plate or baffle
plate 27. Thus the disk 27 is spaced from the bracket flat end face
12f within that said bead; and it may be stiffened by annular
groove 27a. The disk central outlet aperture 27c accommodates the
right bearing socket 18 projecting therethrough and a shield
structure 43, and affords an outlet to the inlet eye of fan 42 for
auxiliary air entering at inlets 28, as hereinafter detailed.
Auxiliary air inlets 28 are provided through the end bracket wall
at angularly spaced locations just within bead .[.27.]. .Iadd.25
.Iaddend.thus lying at a location radially outward of band 20,
hence effectively external of the motor housing structure.
The fan section F actually represents a two-stage design. The fan
housing H conventionally includes shell structure fitted onto the
exterior of the rim 12r, and here comprising two flat-bottomed
cylindrical-walled drawn sheet metal shells 31 and 35. The shell
portion 31, with its cylindrical wall fitted on the rim and
surrounding the radially tapered second stage impeller 32, has a
radial wall with a central opening as the inlet to the eye of the
second stage impeller and having fixed on its outer or rightward
face conventional stationary vanes 33. Thus the discharge periphery
of impeller 32 is axially offset from the housing outlet therefor
to discharge outwardly and then feed axially into the previously
described channel 24.
For a first stage impeller 34 identical to impeller 32, the second
shell portion 35 is telescoped onto a slightly reduced cylindrical
end portion of 31, and in its basically flat-bottomed, i.e., radial
wall region, has a large central inlet opening 36 for flow of
working air axially to the first stage impeller inlet eye. A
concentric annular inward beading 36b provides not only some
structural rigidity for the end wall, but also a degree of pinching
off the area between that housing front wall and the adjacent front
end face of the impeller 34, to some degree to prevent
recirculation from the impeller peripheral discharge area back to
its inlet eye. Both the fans here are shown in a preferred radially
tapering form now known to the art, comprising a main body disk
centrally apertured for the shaft, an annular disk, and a series
vane elements fixed therebetween.
Conventionally the first stage impeller 34 and second stage
impeller 32 are secured on the rightwardly projecting end of the
motor rotor shaft by means of a first axial spacer 37 including a
sleeve portion about the shaft bearing against the inner race of
ball bearing 16 and having a radial flange affording a clamping
reaction surface for the main disk of fan 34; an elongated
interstage spacer 38 between the impellers; an external washer 39
on the outer side of the first stage impeller body disk; and
finally the clamping nut 40 threaded onto the shaft end.
The flow path of a working air from the inlet 36 of the housing H
through the first stage impeller 34, the interstage "stationary
fan" 33, the second stage working impeller 32, to the channel 24
leading to outlet 24a, is indicated by the solid arrows. The flow
path of ventilating air for the motor is indicated by the
dash-dotted direction arrows in the motor section.
Moreover, on the shaft T and between the flanged member 37 and the
main disk of impeller 32, there are further clamped a "non-tapered"
auxiliary fan 42 of appreciably smaller diameter than, and in
back-to-back relation with, fan 32; and also a cup-shaped further
baffle or shield element 43 centered in the eye of fan 42. It will
be observed that the circumferential wall of shield member 43 has a
fairly close running clearance about the rightwardly projecting
bearing socket 18, and also extends axially through the central
opening of the disk 27 towards flat fanward face 12f of end bracket
12. Thus the annular outlet, from the auxiliary air path or flow
space defined between 27 and 12, in effect opens along the exterior
surface of shield cup 43 into the eye of fan 42.
As indicated by the dotted arrow lines, the auxiliary air or
bearing sealing air flows inwardly from the inlets 28, then axially
past the bearing region into the eye of fan 42, and from the latter
discharges, toward the main or working air outlet channel 24,
through the space between the impeller 32 and the effective inner
face of the fan housing, i.e., the disk plate 27. Thus a first
obstacle to foam or detergent movement toward the bearing is
provided by the auxiliary air discharging from fan 42; a second, by
the flow of air through the outlet 27c around the shield 43 into
the eye of fan 42; and a third and fourth, by the presence of the
disk 27 forward of the face 12f in conjunction with the rotating
cup shield both as extending in to the central aperture 27c and
also as surrounding the bearing socket.
* * * * *