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Патент USA US3041128

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June 26, 1962,
J. E. RAMSEY
3,041,117
AIR CLEANER FOR VENTILATED DYNAMO-ELECTRIC MACHINES
Filed NOV. 29, 1960
INVENTOR
JAMES E. RAMSEY
BY f”, Hwf %
ATTO NEY
‘ice
United States atent
3,041,117
Patented June 26, 1962
1
2
3,641,117
tion, of the parts of FIGURE 1 which are pertinent to
the invention.
The machine illustrated has a tubular casing 10 to
AIR CLEANER FOR VENTILATED DYNAMO
ELECTRIC MACHINES
which is ?tted and secured by suitable means, not shown,
end caps 11 and 12 each having an outwardly directed
James E. Ramsey, 111 Aiken Road, ‘New Castle, Pa.
Filed Nov. 29, 1960, Ser. No. 72,332
4 Claims. (Cl. 310-56)
boss 13.
In accordance with usual practice, bosses 13
retain suitable bearings for journaling the machine shaft
This invention relates to an improved arrangement and
14 on which is secured the rotor 15. Reference numeral
apparatus for cleaning the air supplied to the interior
16 denotes the stator of the machine.
_
workings of a dynamo-electric machine, and more par
An end portion of shaft 14 within one of the end caps-
ticularly to an improved arrangement for incorporating
the air cleaning mechanism in the centrifugal blowers
normally utilized to supply a flow of ventilating air longi
tudinally through the casings of such machines. Here
‘12, for example—rnay be reduced in diameter and shoul
dered to receive the hub of a disc-like impeller 17 which,
for small machines, is preferably a precision die casting.
tofore, it has been common practice to house within an
end cap of a dynamo-electric machine, such as a motor,
an impeller keyed to the machine shaft for the two-fold
purpose of creating an air stream for ventilation and
for centrifugally cleaning the air before the same enters
plurality of circumferentially spaced but radially extend
The impeller 17 is provided on its outer face with a
ing vanes 18 which serve to entrap air between the outer
face of the impeller and the adjacent wall of the end cap
12 and to force this air with its entrapped grit and dust
radially outward under centrifugal force. It should be
noted that the end cap 12 has a plurality of air inlet ports
19 adjacent the boss 13 and that these inlet ports are im
mediately radially inward of the inner ends of the
the machine housing. However, since the cleaning ac
tion is by centrifugal force which is coincident with the
building up of the forces to create the pressure differ
ential required for moving the air, it is di?icult to sepa
vanes 18.
rate much of the dust in the air from the air stream
The peripheral portion of the inner face of the im
entering the machine casing, and I have found that the 25 peller 17 is ?anged or lipped as shown at 29 in FIGURE
prior assemblies are de?cient in this regard. The prob
1, and in practice the face of this lip is accurately die
lem is one of more effectively sealing the outer ring-like
formed or machined to be precisely normal to the axis
zone of maximum air pressure and maximum dust velocity
of the central bore through the hub of the impeller, and
and concentration from the space within the machine
this bore is likewise accurately formed or machined to
casing so that the air which is therein compressed and
?t tightly on the shaft 14 and with the aid of the afore
the already separated dust particles which are swirling
mentioned shoulder to be absolutely normal to the axis
around within this zone will not be again intermixed and
of the shaft. The impeller 17 is also provided with a
drawn into the machine housing.
plurality of apertures 21 which, as shown in FIGURE
Accordingly, it is the primary object of the invention
2, are positioned circumferentially intermediate the vanes
to provide, in a ventilating means for dynamo-electric
18 and radially intermediate the ends of these vanes.
machine, an improved yet simple and practical arrange
Clamped between the adjacent end of the casing 10
ment for sealing the annular space adjacent the outer
periphery of the normally employed ventiiating and
and the mounting ?ange of the end cap 12 is the outer
peripheral portion of a ring-like seal 22 which in actual
cleaning impeller from access to the windings and other
practice is made of a tough self-lubricating plastic such
parts Within the machine casing. In this manner 1 may 40 a Te?on or nylon. As shown in FIGURE 1, the ring 22
employ an impeller of maximum diameter to build up
extends radially inward suf?cient to overlie the whole
an effective pressure head for ventilation and to insure
of the face of the lip 20 of the impeller 17. Cemented
maximum dust separation yet without encountering the
or otherwise suitably secured to the inner face of the
problem of having the substantial air velocities resulting
ring 22 radially inward of the inner periphery of the
from the higher head pick up the once separated dust? 45 casing Iii is a vbaffle ring 23 having an enlarged central
particles and draw the same into the machine.
aperture located radially inward of the apertures 21
The above object is accomplished in accordance with
of the impeller 17 but yet being of sufficiently large diam
the principles of my invention by employing a self-lubri
eter to provide ‘for the unrestricted ?ow of air axially over
cating ring-like seal between the space within the ma
chine housing and the space within the end cap or other
the adjacent portion of the machine shaft 14. To com
plete the assembly of my invention I provide, on the
adjacent axial end of the rotor 15 an impeller ring 24
having axial extending blades 25 and, as shown, this
ring is made as large in diameter as possible in rela
enclosure for the impeller contiguous to the periphery
of the impeller so that no air can enter the casing from
the annular Zone housing the outer peripheral portion
of the impeller. A small annular space with a discharge
outlet is provided radially outward of the impeller for
the discharge of grit and dust particles but this space is
su?iciently restricted, however, so as not to lose much
of the pressure head developed by the impeller.
The
compressed air is allowed to enter into the machine
LY in
tion to the diameter of the rotor 15 so that a maximum
centrifugal effect for assisting the circulation of the ven
tilating air may be attained. There is also provided a
dust discharge opening in the lowermost portion of the
side wall of the cap 12, this opening being protected by
a shield 26.
casing through apertures formed in the impeller well in 60 From the above description, it should be observed that
ward radially of the seal.
the impeller 17 is of maximum practical diameter so
The above and other objects and advantages of the
that the peripheral velocity and resultant centrifugal force
invention will become more readily apparent upon con
acting on the grit and dust particles contained in the
sideration of the following speci?cation and the accom
panying drawing wherein there is disclosed a preferred
embodiment of the invention.
In the drawing:
FIGURE 1 is a side elevation, partly in section, of
an electric motor having an air cleaning and ventilating
impeller incorporated therein in accordance with the
principles of my invention; and
FIGURE 2 is an expanded view, in isometric projec
entering air will be of maximum value. When the ma
chine is operating, therefore, such grit and dust particles
contained in the entering air will be violently impinged
against the side wall of the cap 12 and will be swirled
around thereon until they reach the opening in the bot
tom portion of the side wall where they will be dis
charged. Such opening may be of substantial circum
ferential extent to facilitate self-cleaning action of the
space within the end cap. However, the annular space
3,041,117
intermediate the periphery of the impeller 17 and the
outer periphery lying in a plane normal to said axis and
adapted to have a sliding and sealing ?t with said exposed
side wall of cap 12 is rather restricted, as shown, so that a
substantial pressure head of air will be built up in the
face of said sealing ring, said impeller having a plurality
annular ‘zone of the outer peripheral portion of the im
peller. As this pressure builds up, more and more air
will move axially inward through the apertures 21 in the
impeller 17 and then through the large aperture in the
baffle 23 into the region of the vanes 25 of the impeller
24. The centrifugal action imparted by these vanes will
assist in moving the air through the ports mentioned and 10
thus further facilitate the circulation of air axially through
adjacent the center thereof, apertures in said disc~like im—
peller positioned circumferentially between said vanes and
radially intermediate the ends of said vanes, and a dust
the electric machine, the air being discharged therefrom
through the ports 19 in the end cap 11.
It should be observed particularly that the face of
lip 20 of the impeller 17 has a light, sliding, yet accurate 15
?t against the plane side surface of the sealing ring 22
said sealing ring, the central opening through said ba?ie
being of substantially larger diameter than the diameter
so that the entry of dust and air into the casing it) di
rectly from the annular space about the impeller 17 is
discharge opening in the lowermost portion of the side
wall of the cap.
2. Apparatus according to claim 1 further including an
annular disc-like baffle a?ixed to the inner side face of
of said shaft.
3. Apparatus according to claim 2 further including an
impeller on the axial end of said rotor adjacent said ba?ie,
said impeller having an outer diameter approximating the
effectively restrained. Further, since the sealing plane
is normal to the axis of rotation of the impeller, cen
of radially disposed vanes on its side opposite said planar
surface, air inlet openings in the end wall of said cap
outer diameter of the rotor and having a multiplicity of
circumferentially spaced vanes extending axially toward
said ba?ie, said last mentioned vanes being operative by
dust in a radial inward direction between the ring 22
centrifugal effect to aid in drawing air inwardly through
and the lip 20. The tight seal between the radially out
the central opening in said baf?e.
ward portion of the ring 22 and the mounting flange of
4. Apparatus according to claim 1 further character
the end cap 12 of course prevents any axial ?ow of air 25 ized in that said sealing ring is formed of a self-lubricat
and dust radially outward of the impeller.
ing plastic material, and the said end face of said impeller
Having thus described my invention what I claim is:
being accurately formed to lie in a plane parallel with
1. In a dynamo-electric machine having a tubular cas
the sealing face of said sealing ring and normal to the
20
trifugal force assists in preventing the entry of air and
ing, a rotor, and an end cap ?tted over an end of said cas~
axis of rotation of said shaft.
ing and mounting a bearing for journaling the rotor shaft; 30
the improvement of means to supply cleaned cooling air
to said casing comprising a sealing ring clamped between
said casing end and said end cap and extending radially
inward toward the axis of said shaft, said inwardly extend
ing portion of said ring having a plane surface normal 35
References Cited in the ?le of this patent
UNITED STATES PATENTS
923,673
Lord ____ __'___________ __ June 1, 1909
1,963,401
Clason _______________ __ June 19, 1934
to said axis and exposed to the space within said cap, a
FOREIGN PATENTS
disc-like impeller lying within said cap and rigidly mounted
on said shaft and having a planar end face adjacent its
671,285
Germany _____________ __ Feb. 3, 1939
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