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Патент USA US3082705

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March 26, 1963
w. B'USCHHORN
3,082,695
IMPELLERS, ESPECIALLYMSINGLE VANE IMPELLERS FOR ROTARY PUMPS
Filed June 15, 1959,
_ 360'
270 -
‘R O)
FIG.3
'
WALTHER
INVENTOR.
auscnnorm
PU BY Pm‘mbwiapga.
A TTOR N 3 ‘
,.
Unite
3,082,695
1C6
Patented Mar. 26, 1963
2
cu2=the tangential component of the absolute speed c of
3,082,695
the ?ow at the outlet of the vane,
MELLERS, ESPEQIALLY SINGLE VANE
IMPELLERS FOR ROTARY PUMPS
rlzthe radius distance of the vane at the inlet, in relation
Walther Buschhorn, Pegnitz, Upper Franconia, Ger
culzthe tangential component of the absolute speed c of
to the axis of rotation of the vane,
many, assignor to Klein, Sehanzlin & Becker Aktien
the flow at the inlet of the vane.
gesellschaft, Frankenthal (Pfalz), Germany
Filed June 15, 1959, Ser. No. 820,506
As a guiding device is not usually arranged in front of
the impeller, the last term in the bracket of the Equa
tlol‘ll I: r1-cul will be equal to zero, so that the general for
2 Claims. (Cl. 103—115)
The running of rotary pumps free from oscillations and
mu a
vibrations is governed primarily by the construction of
the impellers employed, whereby unequal distribution of
the mass of the individual elements of the impeller in the
course of their manufacture has a particularly disturbing
is obtained. Herein
e?‘ect. Consequently the impellers are dynamically bal 15 r=the radius distance of a vane element, in relation to
anced on a special machine before being ?tted in the pump
the axis of rotation of the impeller,
housing. It is known that a dynamically well-balanced
cu=the tangential component of the absolute speed c at
impeller, particularly one having only a single vane, is
the point of the vane element having the radius dis
not capable of ensuring perfect running of the rotary
- tance r.
pump. This is due to the fact that the transmission of 20
The _work of the impeller according to the invention
energy to the liquid being pumped is not uniform along
transmitted by the vane to the liquid being pumped can
the impeller with the result that the reaction forces re
be expressed by the equation:
sulting therefrom cause one-sided pressure of the im
peller against the stuf?ng-box bearing, packing gaps and
the like, and premature wear at these points. This hy 25 wherein
draulic unbalance of the rotary pumps is overcome in
known manner by increasing the number of vanes of the
> k=a constant and
go=llhe angle at the center, measured between the begin
impeller. Rotary pumps for delivering liquids permeated
with long-?brous and band-like impurities are preferably
‘ ning of the vane and the vane element with the radius r.
equipped with single vane impellers so as to avoid the 30 The constant k is obtained by dividing the given total blade
danger of choking or clogging which has to be feared. It
work Hm and the angle at the centre go between which the
has hitherto been endeavoured to eliminate the hydraulic
vane should or is to extend.
unbalance which is particularly apparent in the impellers,
Thus with the Equation III it is found that the vane
work Hm increases in proportion with the angle at the
by arranging a suitable counterweight on the back of the
impeller vane. This counterweight is naturally dependent
center. Thereby the condition is met at the same time
that the same amount of work is transmitted to the liquid
upon the number of revolutions and the size as well as the
total weight of the impeller and also upon the speci?c
gravity of the liquid to be dealt with. As it is theoreti
cally not determinable, it has to be ascertained empirically
for each impeller. It has already been attempted to elim
being pumped by vane elements opposite to each other.
If the Equation II is treated in the same way as Equa
tion ‘111 and reduced according to the (p into the form
inate the hydraulic unbalance in the case of single vane
¢=k—‘:’§'r-cu
impellers by twisting the vane in spiral shape. In this
The tangential component cu is, according to FIGURE
the shape of the vane empirically for each impeller sep
arately.
(IV)
the course of the vane is clearly determined.
known type of impellers it is also necessary to determine
1, dependent both upon the radius r and also upon the
angle at the center to in the form:
'
The object of the present invention is to produce an
impeller which is not open to the above-mentioned objec
tions. This is attained by plotting the curve of the vane
so that the increase in work per vane element is the same
on opposite sides of the impeller. This measure becomes 50
particularly effective in the case of an impeller provided
with only a single vane extending approximately through
360°, because the shape of the vane which is mostly very
complicated and was hitherto ascertained only empirically,
are inserted, when in Equation Vb
can be determined already in the course of designing.
Moreover, it is likewise advantageous to plot the thickness
V=volume of the quantity delivered,
course of the vane so that its center of mass coincides
b=the width of the vane,
with the axis of rotations. This renders unnecessary the
simultaneous casting of suitable counterweights on the
60
back of the impeller in the manner already practiced.
and the value for 0,, is inserted in IV, the result will be
To ascertain the course of the vane of the impeller ac
cording to the invention, use is made of the known Euler
fundamental equation
65
In Equation I
Hth=the theoretical lift of the pump,
w=the angular speed of the impeller,
g=the acceleration due to gravity,
r2=the radius distance of the vane at the outlet in relation
to the axis of rotation of the vane,
Equation VI represents a linear di?erential equation of
1st order. Its solution reads
70
8,082,695
3
A
The integration constant C is for ¢=Cg 1:2‘, is equal to
V=the volume of the quantity delivered,
g: the acceleration due to gravity,
bathe width of the vane,
g-21r-‘l7)-k+2
C___ _w-21r-b_ 7‘1 w’
*
w=the angular speed of the impeller,
k=a constant equal to the quotient of the requested
theoretical pressure head Hm and the angle at the
V
g-21r-b-k+2
w-V
If this value for C is inserted in Equation VII the ?nal
solution of the differential Equation VII reads:
center (p
so that the work increase per vane element is the same on
vr-wz'l)
7'1
10
In FIGURES 1 to 3 of the drawing the subject matter of
the invention and the above deductions are explained in
detail.
opposite sides of the impeller.
2. An impeller for centrifugal pumps substantially pro
viding hydraulic equalization over the entire operating
range, comprising an impeller, said impeller being formed
by a single vane which extends in the form of a spiral
over essentially 360° and de?nes a pumping passage ex
FIGURE 1 is a diagram of the values used for
the deduction for determining the curvature of the vane.
This ?gure shows in particular the relationship represented
by the Equation V.
tending from a point adjacent the axis of the impeller to
the periphery thereof, said blade de?ning consecutive blade
shape of the vane is shown in FIGURE 4 as calculated
from the values of FIGURE 3.
I claim:
circulation on this element and the product of the ac
celeration due to gravity and a constant k, which con
elements each having a radial distance r with respect to the
FIGURE 3 shows the result of an example calculated
axis of rotation of the blade assigned to a center angle
with the aid of the above developed relationships for a
single vane impeller. Here the angle <p dependent upon 20 measured from the leading edge of the blade to the re
spective blade element, the volume of said passage de
the radial distance of the vane elements is traced graph
termined by said center angle being equal to the quotient
ically. The example is based on a delivery quantity of
of the product of a predetermined angular velocity of the
V=446.4 cubic ‘metres per hour, a speed of 11100 rpm,
impeller, said radial distance r of the respective blade
a constant impeller width of b=130= nuns. and a distance
31 at the beginning of the blade equal to 110 mms. The 25 element, and the tangential component cu of the flow of
stant is equal to the quotient of a predetermined theoreti
cal pressure head Hg, and said center angle over which
1. An impeller for centrifugal pumps, substantially pro
viding hydraulic equalization over the entire operating 30 the blade is to extend so that the work increase per blade
element is the same on opposite sides of the impeller in
range, comprising an impeller, the passage of which is
any radial plane.
formed by a single vane extending in the form of a spiral
approximately over 360°, the curve of said spiral essenti
ally conforming to the equation
g0=the angle at the center, measured between the be
ginning of the vane and the vane element with the
radius r,
r=the radius distance of a vane element in relation to
the axis of rotation of the impeller,
r1=the radius distance of the vane at the inlet in rela—
tion to the axis of rotation of the vane,
35
4O
References Cited in the ?le of this patent
UNITED STATES PATENTS
450,491
963,378
Nicholas et al _________ __ Apr. 14, 1891
Lorenz ______________ __ July 5, 1910
2,245,035
Hartman ______________ __ June 10, 1941
2,655,868
2,853,019
Lindau et al ___________ __ Oct. 20, 1953
Thornton ____________ __ Sept. 23, 1958
1,324
Great Britain _______________ __ of 1863
23,234
340,152
Germany ____________ __ Dec. 30, 1881
Great Britain ________ __ Dec. 24, 1930
FOREIGN PATENTS
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