close

Вход

Забыли?

вход по аккаунту

?

Патент USA US3096940

код для вставки
July 9, 1963
L. MEYERHOFF
3,096,930
PROPELLER DESIGN
Filed June 26, 1961
INVENTOR.
160M490 Maya? HOFF
BY z/
United States Patent 0
1
1
TC€
3,0%,930
Patented July 9, 1963
2
3,096,930
PROPELLER DESIGN
Leonard Meyerhoif, Brooklyn, N.Y., assignor to Leonard
Meyerhoit and Stanley A. Meyerhoif, doing business as
Eastern Research Group, a partnership
Filed June 26, 1961, Ser. No. 119,443
6 Claims. (Cl. 230—12i))
This invention relates to a propeller design which sub
and rotatable about point 12 in the direction shown by
the arrow. Also shown in FIG. 1 is housing wall 13.
The essence of this invention involves the conduit 14
which is shown intersecting the leading edge 15 at entrance
16 of blade 10.
An elogated slot 17, shown in section in FIG. 3, extends
along the entire length of conduit 14.
As blade 10 rotates, ?uid is induced into entrance 16.
This ?uid ?ows through conduit 14 and is directed in a
stantially eliminates problems associated with clearance 10 radial direction through slot 17 so that a curtain of ?uid
between the peripheral edge of a rotating propeller blade
impinges against housing wall 13. By reason of the
and the housing therefor.
relatively high pressures developed at the leading edge 15
In the design of enclosed propellers, such as for example
of the enclosed propeller blade 10, the force with which
a pump impeller or a marine propeller contained within
the ?uid is expelled through slot 17 is considerable. Ac
a duct or housing, the clearance between the peripheral
edge of the propeller blade and the housing must be
designed on ‘a compromise basis.
_
Obviously, a minimum of clearance is necessary in
cordingly, the curtain of ?uid which serves as an extension
of blade 10, prevents back?ow. Further, when the ?uid
is compressible, the density of this curtain varies in pro
portion to the pressure developed at the leading edge 15
of the propeller blade 10 and this pressure varies in pro
order to prevent binding or rubbing between the periph
eral edge of the blade and the housing. In addition to 20 portion to the speed of the blade so that the ‘faster the
this minimum clearance, it is generally necessary to add
blade rotates the denser the curtain and vice versa. This
additional clearance to compensate for the usual toler
is an important automatic regulating feature. With in
ances in production of the various parts which are asso
creased propeller blade speed there is also increased pres
ciated to form the unit.
sure diiferential across the propeller and therefore an
The relatively large clearances that are thus required 25 increase in back?ow pressure which is proportionally
are disadvantageous for several reasons. First, there is
countered by the related increase in density of the curtain.
a loss of e?iciency due to the fact that the ?uid through
Thus, for air utilizing devices, with increase or decrease
which the propeller is rotating is enabled to ?ow from
in blade speed the back?ow pressure and countering cur
the downstream side of the propeller to the upstream side
tain density tend to increase and decrease automatically
through the clearance space. An additional dis-advantage
and in proportion to assure prevention of ‘back?ow at
which becomes of great importance where detection is to
varying blade speeds.
be avoid involves the noise which results from the afore
Although the embodiment shown in FIGS. 1, 2 and 3
mentioned back?ow. This noise results directly from the
has been described in terms of a propeller, it is to be
gap vortex cavitation arising from the large clearance.
appreciated that the invention is applicable to any device
Accordingly, it is an ‘object of this invention to provide
in which a propeller blade is rotated for the purpose of
an enclosed propeller blade design which will provide the
causing a ?ow of ?uid. Thus, centrifugal pumps are
necessary clearance required by factors such as manu
amenable to design in accordance with the present inven
facturing tolerances, while substantially eliminating de
tion, as well ‘as other types of ?uid ?ow devices in which
creased e?iciency and gap vortex cavitation.
40 a blade is rotated within an enclosure.
It is an additional object of this. invention to provide
With respect once again to FIG. 1, conduit 14 is shown
a propeller blade for use in ducts and housings which is
to be tapered. This is the preferred form and is em
provided with a peripheral slotted area thereby creating a
ployed since the magnitude of ?ow within the conduit 14
?uid radial extension of the blade which effectively seals
diminishes uniformly from the entrance 16 ‘downstream.
the clearance area and thus eliminates the disadvantages
45 Accordingly, to insure a uniform flow through elongated
stemming from back?ow.
slot 17, conduit 14 is tapered to diminish the cross-sec
Brie?y stated, the present invention relates to an en
tional areas thereby maintaining ?uid pressure along the
closed propeller blade design in which a conduit is formed
slot while compensating for the loss of ?uid.
within the peripheral area of the blade, the conduit being
The shape or geometric design of entrance 16 is not
provided with an opening in the leading edge of the blade.
critical, and may be chosen so that a decelerating elfect
The conduit is connected to the peripheral edge of the
on the induced ?uid is produced thereby giving rise to
propeller blade by an elongated slot extending substan
an increase in pressure. Conversely if it is desired, the
tially along the entire length of the conduit. Thus, rota
form of entrance 16 may be made to have an accelerat
tion of the propeller causes induction of ?uid into the con
ing effect ‘on the induced ?uid with an accompanying
duit. The induced ?uid in turn ?ows out of the propeller 55 decrease in pressure.
blade in a radial direction through the elongated slot. In
effect, the ?uid ?owing out of the elongated slot forms a
Thus, the presentinvention provides a simple solution
to the problems caused by the necessity for having clear
curtain which acts as a ?uid extension of the propeller
ance between the peripheral edge of a propeller blade
and the housing. Enclosed propeller blades may be de
signed in accordance with this invention with su?icient
clearance to allow vfor all of the standard manufacturing
blade and substantially eliminates back?ow.
The invention may be more readily understood when
described in conjunction with the drawings in which:
FIG. 1 is an elevational view, partly in section, of one
tolerances without being burdened by the disadvantages
embodiment of the enclosed propeller blade design of this
arising therefrom.
invention.
What has been described above is one embodiment of
FIG. 2 is ‘a developed plan view, partly broken away, 65 an enclosed propeller blade design of this invention which
of the propeller blade of FIG. 1 taken along line 2—2
provides radial ?uid ?ow which acts as an extension of
therein; ‘and
the propeller blade. Thus, the disadvantages arising
FIG. 3 is a sectional view taken as shown in FIG. 2.
from back?ow in the clearance between the conventional
With respect now more particularly to the drawings,
propeller blade and housing are obviated.
FIG. 1 is a front elevational view of one embodiment of
The present invention also applies to ?ow devices in
the enclosed propeller blade design of this invention.
which a propeller is driven by the incoming ?ow, e.g.,
Shown in FIG. 1 is propeller blade 10 attached to hub 11
turbine. In such situations, the static pressure of the
3,096,980
?uid ?owing is diminished by passage through the device.
A
of said blade, whereby rotation of said propeller blade
Hence the gap ?ow at the periphery of the propeller or
blade will be in a direction from upstream to down
then ?owing through said conduit and escaping from said
stream, the reverse of the situations described in the
conduit through said slot thereby forming a curtain of
?uid between the periphery of said ‘blade and said hous
3
causes ?uid to enter said opening, the ?uid so entering
examples above. Accordingly, the direction of ?ow from
the conduit is made opposite to that of the illustrative
embodiment.
Although the examples described employ a slot for
ing.
4. In the assembly of a rotatable propeller enclosed
within a housing, a propeller comprising a blade having a
peripheral portion and a leading edge and being mounted
the issuance of a curtain of water, it is to be understood
that advantages of this invention may be ‘obtained if the 10 so that rotation of said propeller causes said blade to
provide a ?ow of ?uid parallel to the axis of rotation,
water ?ow which forms the curtain issues from a single
the periphery of said blade being spaced from the housing
point on the periphery of the propeller. For example,
by an annularly shaped clearance, a conduit con?gured
gap ?ow is known to curl into a rope-like gap vortex
substantially similar to and located adjacent the peripheral
which can be destroyed by the aforementioned single
point issuance.
15
portion of said blade, said conduit intersecting the leading
edge of said blade and having an opening formed at
More than one curtain of ?uid may be employed in
such intersection, an elongated slot located in the pe
accordance with this invention to obtain increased ad
ripheral portion of said blade and being longitudinally
vantages. Thus, the use of a double curtain would pro
coterminous with said conduit, said slot longitudinally
portionately decrease the gap ?ow.
It is to be understood that the embodiment described 20 intersecting both the conduit and the periphery of said
blade, whereby rotation of said propeller blade causes
above is intended merely as illustrative of the present in
?uid to enter said opening, the ?uid so entering then
vention and that variations may be made therein by one
?owing through said conduit and escaping from said
skilled in the art without departing from the spirit and
conduit through said slot thereby forming a curtain of
scope of .this invention.
What is claimed is:
25 ?uid between the periphery of said blade and said housing.
1. An enclosed propeller blade assembly comprising a
, 5. In an assembly of a rotatable propeller enclosed
within a housing, a propeller comprising a blade having a
blade mounted to rotate about an axis, a housing for
said blade, said housing being circular in shape and con
centric with the cylindrical surface described by the
periphery of said blade leaving a determinate clearance
between its inner surface and said cylindrical surface,
peripheral portion and a leading edge and being mounted
the said blade having a peripheral portion and a leading
edge and being provided with a conduit con?gured sub
centric With the said axis of rotation, a conduit located
so that rotation of said propeller causes said blade to
provide a ?ow of ?uid parallel to the axis of rotation,
said blade having a curved periphery substantially con
adjacent the peripheral portion of said blade, said conduit
stantially similar to and located adjacent said peripheral
having a curved longitudinal axis which substantially
portion, said conduit intersecting the leading edge of 35 follows the curvature of the periphery of said blade,
said blade and having an, opening formed at such inter
section, an elongated slot located in the peripheral por
said conduit intersecting the leading edge of said blade
and having an opening formed at such interesection, an
tion of said blade and being longitudinally coterminous
elongated slot located in the peripheral portion of said
with said conduit, said slot longitudinally intersecting
blade ‘and being longitudinally coterminous with said
both the conduit and the periphery of said blade, where 40 conduit, said slot longitudinally intersecting both the
by rotation of said propeller blade causes ?uid to enter
conduit and the periphery of said blade, whereby rota
said opening, the ?uid so entering then ?owing through
tion of said propeller blade causes ?uid to enter said
said conduit and escaping from said conduit through said
opening, the ?uid so entering then ?owing through said
slot thereby forming a curtain of ?uid between the '
conduit and escaping from said conduit through said slot
periphery of said blade and said housing.
thereby forming a curtain of ?uid between the periphery
,2. In the assembly of a rotatable propellerenclosed 45 of said blade and said housing.
within a housing, a propeller comprising a blade having
a peripheral portion and a leading edge, a conduit con
?gured substantially similar to and located adjacent the
peripheral portion of said blade, said conduit intersect
6. In the assembly of a rotatable propeller enclosed
within a housing, a propeller comprising a blade having
a peripheral portion and a leading edge and being
mounted so that rotation of said propeller causes said ,
ing the leading edge of said blade and having an open 50 blade to provide a ?ow of ?uid parallel to the axis of
ing formed at such intersection, an elongated slot located
rotation, said blade having -a curved periphery substan
in the peripheral portion of said blade and being longi
tially concentric with the said axis of rotation, a tapered
tudinally coterminous with said conduit, said slot longi
conduit con?gured substantially similar to and located
tudinally intersecting both the conduit and the periphery
adjacent the peripheral portion of said blade, said conduit
55
of said blade, whereby rotation of said propeller blade
having a larger cross-sectional area adjacent the leading
causes ?uid to enter said opening, the ?uid so entering
edge of said blade, said conduit interesecting the leading
then ?owing through said conduit and escaping from
edge of said blade and having an opening formed at
said conduit through said slot thereby forming a curtain
such intersection, an elongated slot located in the pe
of ?uid between the periphery of said blade and said
tripheral portion of said blade and being longitudinally
60
housing.
coterminous with said conduit, said slot longitudinally
3. The combination comprising a propeller having at
interesecting both the conduit and the periphery of said
least one blade having a peripheral portion and a leading
blade, whereby rotation of said propeller blade causes
edge mounted thereon so that rotation of said propeller
?uid to enter said opening, the ?uid so entering then ?ow
causes said blade to provide a ?ow of ?uid parallel to
ing through said conduit and escaping from said conduit
the axis of rotation, a conduit con?gured substantially 65 through said slot thereby forming a curtain of ?uid be
similar to and located adjacent the peripheral portion of
tween the periphery of said blade and said housing.
said blade, said conduit intersecting the leading edge of
References Cited in the ?le of this patent
said blade and having'an opening formed at such inter
section, a housing surrounding said propeller, an ‘an
UNITED STATES PATENTS
nularly shaped space between said housing and the cylin 70
2,156,133
Troller ______________ __ Apr. 25, 1939
drical surface described by the periphery of said blade
when said propeller is rotated, an elongated slot located
2,597,510
McBride ____________ __ May 20, 1952
in the peripheral portion of said blade and being longi
FOREIGN PATENTS
tudinally coterminous with said conduit, said slot longi
400,913
Great
Britain ______________ __ of 1933
tudinally intersecting both the conduit and the periphery 75
Документ
Категория
Без категории
Просмотров
0
Размер файла
422 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа