Improvements in Elastic Fluid Turbines.
Year: 1896

page_text: Date of Application, 1st Sept., 1896-Accepted, 23rd Jan., 1807
COMPLETE SPECIFICATION.
Improvements in Elastic Fluid Turbines.
I, CLAUDE KENNEDY MILLS, of 23 Southampton Buildings in the County of
London, Patent Agent, do hereby declare the nature of this invention, a com-
munication to ine from Charles Gordon Curtis, Eugineer, of 441 Park Avenue,
New York City, in the County of New York and State of New York, in the
United States of America, and in what manner the same is to be performed to
be particularly described and ascertained in and by the following statement :-
The method employed consists in converting the pressure of the fluid into vis riva
by stages and utilizing the vis vira developed at each stage by passing the fluid
through rotating vanes the speed of revolution of which is adapted to abstract
Fubstantially all or a large portion of the velocity. In practicing this method
a definite amount of the initial pressure of the fluid is first converted into vis viva
by parsing a jet of fluid through a nozzle or passage properly proportioned to give
the desired result and the flowing jet is delivered to a movable clement of the
apparatus consisting of one or more circular ranges of vanes forming passages
through which the jet passes and in which its direction of flow is changed so as to
extract its velocity wholly or largely, whereby the vis viva developed in the nozzle
or passage is wholly or largely converted into mechanical rotation. The fluid
issues from this movable element into a stationary passage which is so proportioned
as to convert a further definite amount of the pressure remaining in the fluid into
tis rira, and which delivers the fluid in a jet to the second movable element
consisting of one or more circular ranges of vanes by which the direction of the
flow of the jet is changed and its velocity is again wholly or largely extracted,
whereby the vis riva developed in the intermediate passage is converted wholly or
largely iuto mechanical power. The energy of the fluid may be converted into
mechanical power in two or more such steps or stages, but it is essential that the
various stages be so co-ordinated that the flow through the apparatus shall be
continuous. To this end the successive working passages to which the jet is
admitted in the movable elements of the apparatus are enlarged in cross section
and correspond in size with the discharging ends of the successive stationary
passages, and in each element in which vis riva is developed, provision is made for
carrying the same mass of fluid as is admitted to the first nozzle or passage having
regard to the volume and velocity. The pressure of the fluid jet is not reduced
during its passage through the utilizing vanes, except to the extent necessary to
supply what may be called the frictional consumption of energy in the passage
through the vanes. The passage must be enlarged in proportion thereto.
The movable elements of the apparatus in which the vis vica developed at each
stago is utilized, may consist of single sets of rotating vanes, or of two or noro
such sets with intermediate stationary vanes or passages, or of two or more sets of
rotating vanes connected to different shafts.
The velocity developed and utilized at each stage may be the same in which
case the speed of the several movable elements will also be the same; or the
former may not be the same, in which case the latter will also vary. The movable
elementa may be mounted on the same or different shafts. If they are mounted on
the same shaft but have different rates of motion their diameters should be different,
so that the speed at the shaft may be the same.
The constructional features of the apparatus, which constitute other features of

page_text: the invention, are applicable to an apparatus operating by the special method
referred to, but may also be applied to an apparatus in which the steam or other
elastic fluid has a considerable velocity after passing through each movable element
of the apparatus except the last, as described in an application for patent filed
simultaneously herewith. The more important of these constructional features are
as follows: The movable elements of the apparatus are divided between two or
more separate fluid tight shells or casings connected together by suitable stationary
passages. Within each of the shells, the movable element may be single or
compound.
The effect of this construction is to maintain different pressures in the two or
more fluid tight shells, which pressures will approximate the pressures existing in
the working passages at the clearances between the movable and stationary parts
in each shell. This reduces the leakage at the clearances. Such leakage as does
take place, however, into any shell except the last shell of the series does not
result in a waste of power since the excess fluid re-enters the working passages of
the turbine at the clearance between the exit passage and the movable vanes aud
is utilized in the succeeding set of vanca. This construction is particularly useful
in the form of apparatus in which a considerable portion of the pressure is still
retained by the fluid when it enters the first movable element of the apparatus,
but it is a desirable construction in any compound elastic fluid turbine, oven in one
where the entire useful or available pressure is couverted into vis viva hy the
delivery nozzle which delivers the fluid to the first set of movable vanes, because
in a compound apparatus more or less pressure must exist even at the end of the
delivery nozzle, in order to overcome friction in the working passages.
It is also intended that the apparatus shall not be subject to the loss in efficiency
arising from the friction of the elastic fluid in passing through the working
passages. The friction produces heat in the walls of the passages, which may be
considerably greater than the heat of the steam or other elastic fluid. The energy
represented by this heat will be lost to a great extent if the working passages are
allowed to cool off.
To prevent this, the working passages are covered with a heat non-conducting
material. To do this effectively, the delivery nozzle, the intermediate stationary
passages when employed, and the shell or shells, must all be covered. The
covering of the nozzle and the intermediate stationary passages secures the result
so far as those parts of the apparatus go, and the covering of the shells prevents
the cooling of the movable vanes as they move through the atmosphere within the
sbells, the heat of such atmosphere being maintained by the heat insulation of the
shells themselves. The result of this heat insulation of the working passages is to
cause such passages to be heated by the friction of the fluid to such au extent
above the heat of the fluid itself that a point of equilibrium will be reached where
a definite temperature will be maintained, and the heat produced by friction will
re-act upon the fluid jet and be reconverted into energy within the jet.
The heat insulation of the shells has also the additional result of preventing loss
by condensation within the shells.
It is the design of the method and apparatus, as of the apparatus of the prior
application referred to, to employ at the delivery end of the nozzle and in the
working passages a "jet" of steam or other elastic fluid, ie., a practically solid
stream of fluid having an oblong form in cross section, whose thickness bears a
considerable proportion to its width, so that its cross sectional area will be large
compared with its perimeter as distinguished from an annular film of elastic fluid,
whose cross sectional arca is small compared with its perimeter.
By this means the frictional retardation is greatly reduced and the efficiency is
largely increased.
In the accompanying drawings forming a part hereof :-
Fig. 1 is a vertical section of one form of the apparatus, with the nozzle and
interniediate stationary passages brought into the same vertical plane, for clearness
of illustration,
3.

page_text: Fig. 2 is a viow similar to Fig. 1, showing a nozzle with parallel walls instead of
diverging walls;
Fig. 3 is a horizontal section through the nozzle and interinediate stationary
passages of the apparatus of Fig. 1, these parts being brought into the same
horizontal plane, and the vanes of the movable elemonts of the apparatus being
partly developed in the same horizontal plano;
Fig. 4 is a plan view on a larger scale of some of the movable vanes developed ;
Fig. 5 is a side view and partial vertical section, with the nozzles and
stationary passages brought into a vertical plane, showing a modified form of the
apparatus;
Fig. 6 is a side elevation of a further modification;
:
Fig. 7 is a vertical section of one movable element employing three sots of
movable vanes ;
Fig. 8 is a vertical section similar to Fig. 1, illustrating elements of different
diameters mounted on the same shaft;
J
Fig. 9 is a horizontal section; with the passages brought into the same
horizontal plane, of the second element of the apparatus of Fig. 8, the movable
vanes being partly developed;
Fig. 10 is a plan view, showing an apparatus of two elements delivering the power
to two different shafts, the nozzle and intermediate stationary passage being brought
into a horizontal plane; and
Fig. 11 is a similar view, showing an apparatus of four elements working on two
shafts.
Referring particularly to Figures 1, 2 and 3; A is the shaft, upon which are
mounted four discs or wheels B, C, D and E, each carrying on its periphery a
complete circular range of curved vanes a which form the sides of curved passages
extending parallel with the shaft from side to side of the disc and closed at their
tops and bottoms. The discs are mounted in separate stationary shells F, G, HI
and 1, which are properly packed about the shaft so as to prevent leakage. K is
a pipe or conduit leading from the steam boiler or other source for supplying the
fluid under pressure. This pipe terminates in a nozzle L, which may have
diverging sides, as in Fig. 1, or parallel sides, as in Fig. 2. The end of this nozzle
passes through one side of the shell F and approaches closely the receiving ends of
the movable vanes a of the disc B, to which it delivers the fluid jet. Tho nozzle L
is placed at an angle, as shown in Fig. 3, while the vaues a have the configuration
more particularly shown, in Fig. 4, and receive the jet on their concave sides and
tend to change its direction of motion over 90 degrees, which change would occur
if the vanes were held stationary. Owing, however, to the fact that the speed of
the vanes is about half that of the jet, the jet issues from the tails of the vanes at
about right angles to the disc B. The jet is then received by the intermedinte
stationary passage M. This passage is widened out at its receiving end 6 so as to
cover all the vanes to which the nozzle delivers the jet, which, duo to "spill" and
to the lead, will be greater than those actually covered by the end of the nozzle.
The passage M terminates in an expansion nozzle similar to the nozzle L but
larger so as to carry the increased volume of fluid due to its diminished pressure.
This second expansion nozzle is adapted to convert a further amount of pressure
into velocity and is arranged obliquely with reference to the ranes of the disc C
at the proper angle to deliver the fluid jet to such vanes the same as the nozzle L
delivers the fluid jet to the vanes of the disc B. Back of the expansion nozzle
with which the passage M terminates, that passage may be a conduit of any
suitable size and shape so long as it is large enough to accommodate the fluid at
the increased volume due to its decreased pressure. The vanes of the disc Care
Jarger than those of the disc B, so ae to give additional cross-sectional area to the
passages between them. Between the disca C and D is a stationary passage N
corresponding with the passage M, and another similar passage is located
between the discs D and E, each of these passages terminating as does the passage M
in an expansion nozzle of larger size, than the preceding one and adapted to convert

page_text: pressure into ris vira. The exhaust pipe P, opening into the air or connected with
a condenser, opens out of the side of the case I opposite the vanes a in the disc E
to which the fluid jet is delivered by the passage O.
The apparatus described and illustrated is proportioned to operate by the method
which constitutes a part of the present invention. The delivery nozzle L and the
nozzles of the successive stationary passages M, N, and O, are designed each to
produce the same velocity, which is practically or largely extracted by each set of
the movable vanes, which receive the fuil jet in succession. The manner of
proportioning tho relations between the receiving and discharging ends of the
delivering nozzle and the nozzles of the stationary passages will be understood
from the explanation of the delivery nozzle given in the application already
referred to.
In Figures 1 and 2, the apparatus illustrated is designed, in each instance, to
convert in the two or more successively acting nozzles all the useful or available
energy into vis viva, each one of these nozzles developing the same velocity in the
jet as each of the others, and each set of movable vanes extracting practically all
this velocity and being made successively larger in cross section to compensate for
the increased volume of the fluid jet. The apparatus of Figure 1, however, is
designed to work under different terminal pressures from that of Fig. 2. For
purposes of illustration, let it be assumed that the apparatus of Fig. 1 is designed
to work between a boiler pressure of 150 pounds and an exhaust pressure of
2 pounds, these pressures being absolute and not by gauge (this exhaust pressure
corresponding to about 26 inches of vacuum).
The pressure existing at the discharging ends of the nozzle Land of the nozzles
of the intermediate stationary passages M, N, and O, will be such as to develop
practically equal velocities at the delivery end of each of these nozzles, this velocity
being roughly 1700 feet per second. The apparatus of Fig. 2 is intende.l to
represent a non-condensing turbine, operating between a boiler pressure of
150 pounds (absolute) and an atmospheric exhaust, say 16 pounds pressure.
this case, the pressures at the discharge ends of the nozzle Land of the nozzles of
the intermediate stationary passages M N and O, will likewise be such as to
develope practically equal velocities at each nozzle, and in this case such velocity
will be roughly 1300 feet per second.
In
In Fig. 5 is illustrated a form of apparatus having three movable elements, each
of which is compounded once, or has two series of movable vanes. The movable
elements are wheels or drums Q, R and S having on their peripheries two sets of
vanes c, d which are separated by a stationary passage e carried by the casing.
The construction of these movable vanes and stationary passages, and their
relations to each other, will be understood from Fig. 9, which will be presently
described. Although each movable element may be enclosed in a soparate casing,
as in the appuratus of Figures 1 and 2, in the form of apparatus shown in Fig. 5
the first two movable elements and the intermediate connecting passage M are
enclosed in the shell T, while the third movable elemont is enclosed in the shell U,
the intermediate passage N connecting the two shells. In this apparatus, the
delivery nozzle L and the nozzles of the stationary passages M and N are designed
to develope the same velocity in the jet which is, in each case, one third of the
total velocity utilized in all the movable elements combined. Each of the movable
elements is compound, having two sets of movable vanes and an intermediate
stationary passage e which is not designed to develop additional velocity but is
expanded in the direction of flow to compensate for the reduced velocity produced
by the movable vanes c aud for increased volume required to overcome frictional
retardation, as described in my application already referred to. It is the especial
design of the apparatus of Fig. 5 that the pressure in the first shell T should be
approximately atmospheric pressure, while that in the second shell U should be
the condenser pressure, or say 26 inches of vacuum. Assuming terminal pressures
of 150 pounds and 2 pounds (absolute), the pressures at the discharge cuds of the
Dozzle Land of the nozzles of the passages M and N will be adapted accordingly,

page_text: and the velocity at each of these points will be practically 1900 feet per second.
The pressure at the receiving end of the passage N will bo approximately.
atmospheric pressure, and that will be approximately the pressure of the elastic
fluid, within the shell T, which pressure will bo determined by the pressure
existing at the clearance between the receiving end of the passage N and the
movable vanes d of the element R, through which clearance the excess of steam
within the shell T will be drawn into the working passages and utilized. The
difference between the pressure existing at this clearance and that existing at
the clearances between the nozzle L, the passage e and passage M and the
vanes c, d, will be such that there may be considerable leakage into the shell, but.
this leakage will not be a wasteful one, because the fluid will be again introduced
into the working passages of the apparatus at the entrance of the passage Ni
In Fig. 6 is illustrated an apparatus in which three elements, each compounded
once, are introduced into a single shell. The delivery nozzle and the nozzles of
the intermediate stationary passages are designed to secure the successive conversion
of pressure into velocity and the movable vaues convert the velocity into mechanical,
motion, as in the case of the apparatus of Figure 5.
In Fig. 7 is shown a sectioval view of one element of an apparatus compounded.
twice or having three series of movable vaues. This movable element is enclosed
in its own casing or shell, from which leads a stationary passage, terminating in an
expansion nozzle connecting with another movable element, the apparatus being
one or two or more movable elements with connecting passages having expansion
nozzles designed to convert the pressure into velocity.
In Fig. 8, an apparatus with two movable elements is shown, the movable
elements being mounted upon the same shaft and each element being compounded
once. In this apparatus, the velocity produced by the expansion nozzle L is
intended to be greater than that produced by the expansion nozzle of the
passage M. For illustration, assuming terminal pressures of 150 pounds and
2 pounds (absolute), the pressures at the discharging ends of the nozzle Land of
the nozzle of the stationary passage M may be arranged so that the velocity at
those two points may be respectively 3000 and 1500 feet per second. The velocity
of the fluid jet as it is discharged by the nozzle of the passage M being only one
half of the velocity at the delivery end of the nozzle L, the speed of the vanes of
the second movable element will be only one half that of the vanes of the first
movable element. To compensate for this difference in speed, the diameter of the
second movable element is inade one half, so that the proper speed at the shaft
will be the same for the two elements. In this fig. is also illustrated a heat
non conducting packing which covers the nozzle L, and passage M, and the shell
of the first movable element, and may also cover the shell of the second movable
element. This heat non-conducting packing prevents the loss of energy by
friction in the working passages to a great extent, as already explained, and also
reduces the condensation in the shell to a minimum. A pipe g with a suitable
valve is employed to draw off any water of condensation which may collect in the
shell.
Fig. 9 is a horizontal section and plan view indicating the vanes and connecting
passages of the second element of the apparatus of Fig. 8. This view equally well.
illustrates the same parts of the second element of the apparatus of Figure 5.
The special feature illustrated by this figure not shown in the other figures of the
drawing, is the employment, for the stationary passage e between the two sets of
movable vanes in a compound movable clement, of a wide passage divided into a
vanes but
number of separate passages by vanes corresponding with the movable
placed in a reversed position.
The object of this divided passage is to avcid eddy currents, which might
occur if an undivided wide passage were employed at this part of the apparatus,
because the fluid jet enters this intermediate passage with approximately one half
of the velocity which it had on entering the vanes c.
The divided passage is also in its nature an adjustable passage, because the fluid

page_text: will not spread out beyond the special sections of the passage to which it is
delivered, and in this way the increased "lead" in passing from the state of rest
of the movable vanes up to their full speed will be provided for without increasing
the width of that portion of the passage which is occupied by the fluid jet.'
In Figures 10 and 11 two shafts V. W. are operated by the same apparatus, tho
elements of the apparatus being divided between the two shafts, and these
elements being connected together by the stationary passages and nozzles the
same as if they were mounted upon one shaft. In Fig. 10 the apparatus is
composed of two elements, one on each shaft, while in Figure 11, the apparatus
has four elements, two being on each shaft.
It is obvious that each rotating element of the apparatus may be mounted upon
separate shafts, in which case there may be as many shafts as there are rotating
elements to the apparatus; and it is also obvious that the direction of rotation in
each case will depend upon whether the vanes and the successively acting nozzles
are set to produce rotation in one direction or in the reverse direction, and
consequently that the same apparatus may produce rotation in opposite directions
on different shafts.
It will be observed that in all the constructions illustrated, the successively acting
nozzles deliver the fluid jet to a part only of the vanes of each set; in other
words, tho delivery ends of the two or more nozzles occupy only a small portion
of the peripheries of the wheels. This is an important feature of the apparatus,
because, as distinguished from an apparatus in which the fluid is delivered
simultaneously to the entire circular range of vaues, tho diameters of the wheels
may be increased without decreasing the height of the vanes, as is necessary in
apparatus where the fluid is delivered to the entire periphery in order to prevent
the undue enlargement of the fluid passage.
It is evident that the constructional features of the apparatus, such as the
division of the movable elements of the apparatus into two or more parts located
in separate fluid tight shells, and the heat insulation to secure the reconversion
of the heat produced by friction in the working passages into energy in the fluid
jet, are applicable to elastic fluid turbines wherein the pressure of the fluid is
substantially all converted into ris viva by the expansion delivery nozzle which
vis vira is fractionally abstracted by successive pasenge through movable vaues,
as described in an application for patent filed simultaneously herewith.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
I
1. In a compound elastic fluid turbine, the combination with movable vanes, of
a series of expansion passages delivering the fluid to two or more movable vanes
in succession, said expansion passages being adapted to convert in successive
operations or stages different portions of the pressure of the fluid into vis viva and
said movable vanes being adapted to abstract at each passage therethrough
substantially all or the principal portion of the vis viva developed at the preceding
stage, whereby the pressure will be alternately converted into vis vitu and
abstracted in stages, substantially as set forth.
2. In a compound elastic fluid turbine, the combination with two or moro sets of
rotating vanes (each eet comprising two or more movable vaues through which
the finid jet is passed in succession), of an expansion nozzle and one or more
stationary intermediate expansion passages, substantially as set forth.
3. In a compound elastic fluid turbine, the combination with two or more sets of
rotating vanes, each set being single or compound, and two or more fluid tight
shells or casings enclosing the said sets of vanes (one or more within each shell),
of a nozzle delivering a fluid jet to a portion of the vanes, within the first shell,
and one or more intermediate passages connecting the different shells together aud
delivering the fluid jet to a portion of the vanes of the different sets in succession,
whereby different pressures will be maintained in the shells approximating those

page_text: at the clearances, and any leakage into any shell other than the last will be
returned to the working passages, substantially as set forth.
4. The combination of a series of separate fluid tight shells, each enclosing a set
of rotating vanes, and a series of expansion nozzles or passages converting pressure
into velocity and delivering the fluid to the sets of rotating vanes in succession,
each succeeding expansion nozzle or passage having an increased cross sectional
area adapted to convey the quantity of fluid received from the previous shell, but
nt a diminished pressure, and each having a ratio of expansion adapted to convert
the desired amount of pressure into vis viva, substantially as set forth.
5. In a compound elastic fluid turbine, the combination with two or more rotating
elements enclosed in two separate fluid tight shells, of a delivery nozzle, an inter-
mediate stationary expansion passage and a vacuum exhaust, the nozzle, rotating
elements and stationary passage being so proportioned that the pressure in the
first shell will be approximately atmospheric pressure, and that in the second shell
will be the vacuum exhaust pressure, substantially as set forth.
6. In a compound elastic fluid turbine, wherein the pressure is alternately
converted into ris vira, and abstracted by stages, the combination with two or
more rotating elements having different rates of speed and constructed with
diameters proportional to such different speeds, of a nozzle, and one or more inter-
mediate stationary passages having the capacity to convert the pressure into
different percentages of vis civa, substantially as set forth.
Dated Sentombon Let 1900
HARRIS & MILLS,
23 Southampton Buildiuge, Loudon, W.C., Agents.
HARRIS & MILLS,
23 Southampton Buildiuge, Loudon, W.C., Agents.