Improvements in Turbines Driven by Steam or Gas.
Year: 1894

page_text: Date of Application, 5th Apr., 1894
Complete Specification Left. 29th Dec. 1894-Accented. 23rd Mar.
1.89.5
PROVISIONAL SPECIFICATION.
Improvements in Turbines Driven by Steam or Gas.
I, LOUIS BOLLMANN an Engineer II Obere Donaustrasse 93 in Vienna Austria
do hereby declare the nature of this invention to be as follows: :-
The object of this invention is, to reduce the velocity, with which turbines
driven by steam are now generally rotating, and also to apply the steam more
economically by expanding it usefully to a high degree. The velocity of steam,
escaping with high pressure into the atmosphere is very great, and as the buckets
of the turbine wheel should move at least with half of that velocity, a rational
turbine requires a speed, which is impracticable; for example, if the steam pressure
is 10 atmosphere, a wheel of 20 inches (meter) active diameter would require
about 20,000 revolutions per minute, which speed is not practicable.
According to my invention the steam does not act directly on the turbine, but
is mixed with a large mass of air, which takes up its energy of impulse at a
reduced speed and drives the turbine at a moderate velocity.
tube
a,
In order to explain the nature of this invention, the following experiment, shown
in Fig. 1, may serve, in which A is a flat disk with a tube a, and B is a second
plate. If A is held close over B, and a strong current of air led through the
B will not be blown away from A, as might be expected, but is drawn
towards A, even if a weight be attached to it. On account of its momentum
the air tends to maintain the velocity, with which it passed through the tube;
but the area of its way between the plates increasing towards the circumference
of the latter, this velocity can only be kept up, if the air gradually expands
below the pressure of the atmosphere. A space of rarified air is therefore
produced between the plates, against which the outside air presses, and thus
bolds B freely suspended towards A.
If steam is led through a, its expansion between the plates reduces its specific
weight, and sets part of the heat in action, in form of a powerful expansive force,
which produces a further acceleration of the velocity of the escaping current.
If it escapes through a straight tube or an opening in the boiler, the pressure
of the steam in the air will be 1 atmosphere; but if plates A B are suitably
applied, this pressure will be much lower. If, for example, the steam pressure in
the boiler is 10 atmosphere, the density of the escaping steam will be only
0.29 atmosphere. It is obvious, that the entire energy due to the boiler pressure
as well as that, due to the expansion from 10 to 0.29 atmosphere becoines
accumulated in the current as momentum of impulse, producing in it a velocity of
3550 feet (1084 meter) per second. The form of the current is that of a very
thin disk, tending to increase its diameter in the air.
To give an idea of the dimensions of the parts, the following numbers, relating
to the measures of a 5 horse power turbine driven by steam of 10 atmosphere, are
introduced, whereby the diameter of the plates A B is 34 inches, and the thickness
of the disk current part of an inch.
Supposing that steam would not mix with air, the above thickness would be
further reduced, as the diameter of the disk current increases, firstly, because the
greater circumference requiring the thinning to keep up the sectional area, and
secondly, because the air pressing on the sides of the current, condenses the steam
to the tensity, corresponding to 1 atmosphere. At the diameter of 20 inches
(near G in Fig. 1) the thickness would thus be
1 of an inch.
1550

page_text: But steam and air have an intense tendency to mix and to diffuse one in
another; in a closed vessel containing air, steam will enter and expand in the
same manner as if there were a vacuum in it, the molecules of the steam entering
between the atomes of the air, the same as water can take up large quantities
of different salts without any increase of the volume of the same.
In Fig. 1 are K K disks of 20 inches in diameter, so situated in relation to A B,
that the current passes between, and that air can freely enter at J J, as indicated
by arrows. As the steam mixes with the air, it imparts its momentum to the
latter at a reduced speed and drives it towards G, producing thereby a rarified
space at JJ, which draws in fresh air by suction.
The distance between the plates A B, and the areas of the apertures for the
admission of the air at J J, can both be regulated, in order to adjust exactly. the
proportion of the steam to the air. It is proposed that for 1 pound of steam of
10 atmosphere, 40 pounds of air are to enter at J J, which proportion can however
be varied according to circumstances and experience.
In consequence of the steam mixed in the mass of air, will the temperature of
the latter be raised, until that of the mixture corresponds to the quantity of heat
contained in the latter. If the temperature of the entering air is 10 degrees Cent.
(= 50° Fahrenheit) that of the above mixture will be 30 degrees Cent. (= 86° F.),
a part of the steam being thereby condensed, and the air expanded, which causes a
further transfer of heat into mechanical energy, to increase the momentum of impulse
of the mixture. The entire motive force, thus set free by the action of the steam
between the plates A B, and in the mixing space between K K is theoretical about
the same as that produced by expanding the steam, until its temperature is reduced
from 180 degrees Cent. (=437° Fahrheit.) to 30 degrees Cent. (= 86° F.) or its
pressure from 10 to 34 atmosphere. The heat transfered to the air produces there
the same energy, as it the steam had been expanded alone, until its tempature is
reduced as above stated.
The mixture, consisting of air, steam and water of condensation (which latter
being finely divided remains suspended) obtains at the circumference G a velocity
of 516 feet per second which is about of that of the steam, escaping from the
plates A B.
From the circumference of the disks K K the mixture flowes directly through
the guide plates to the buckets of the turbine wheel, whose axis of rotation is in
the centre of the plates A B.
The above velocity (516 feet p. second) would require about 3000 revolutions
per minute for a turbine of 20 inches active diameter; this speed may be still too
high for general use, and it can be further reduced either by increasing the
proportion (1 to 40) between steam and air, or by using a serial turbine,
consisting of several turbine-wheels, through which the mixture fiows from one
to the other, whereby its velocity and momentum is reduced successively in each,
until the latter are only 3 or 4 per cent, of those with which it entered into the
turbine. With 3 wheels, 750 revolutions per minute are obtained.
The construction of a serial turbine can be either with all wheels connecte.l
and fastened to one shaft, and stationary guiding-buckets placed between each
pair, which receive the current from one wheel, and reverse it for the next one,
so that it will enter in all wheels in the same direction; or using two sets of
wheels fastened to two separate shafts rotating in opposite directions to each
other, the mixture passing from one wheel into the next one running opposite, in
which case the stationary reversing guiding buckets between the wheels are
avoided.
The plates A B and K K might be formed conical, in which case the current
becomes the same shape; the latter may also be divided into fine streams in
radial or conical direction.
This invention can also be applied for heated or compressed air or other gas,
or mixtures of such, and for coal gas, ignited or exploded during or before use,
in which latter case the current may be intermittent instead continuous. Instead

page_text: of air being mixed with the current of steam or gas, escaping from the plates AB,
other gases or substances can be used to reduce the velocity, as for example
liquids, evaporating at a low temperature. The pressure with which the air or
other substances are led to the current, escaping through the plates A B, may be
higher than one atmosphere and a pump or other contrivance may be used for it.
Dated this 3rd day of April 1894.
Improvements in Turbines Driven by Steam or Gas.
I LOUIS BOLLMANN an Engineer of Vienna in Austria II Obere Donau-
strasse 93 do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in
and by the following statement :-
This invention relates to turbines, driven on by steam (or compressed gas) and
its object is, to reduce the speed, with which such motors have been rotating, and
to expand thereby the steam usefully to a high degree. The steam acts not
directly, but transfers its inertia acquired while escaping into the air, to a large
quantity of air or other gas, whose weight is much greater than that of the steam
used, the mixture acting then with reduced velocity on the turbine, and rotates it
at a moderate speed.
Fig. 1 of the drawings is a vertical central-section of a turbine ;
Fig. 5 is a vertical section through the axis, and
Fig. 6 a front-view of a modified arrangement.
Similar letters denote the same or corresponding parts.
In order to explain the nature of a part of my invention, I call attention to the
following experiment: A, in Fig. 2, is a plate with a tube a, and B a second plate.
If A is held close over B, and a current of air passed through the tube a, the
plate B will not be blown away from A, but is drawn towards A, even if a weight
be attached to it.
On account of its inertia, the air will tend to retain the velocity it had in the
tube; but the area of its passage between the plates increasing towards the edges,
this velocity can only be kept up, if the air expands below the atmospheric pressure.
A space of rarefied air is therefore produced, against which the outside air presses,
and holds B freely suspended towards A.
If the air is of high pressure, this expansion reduces the specific weight of the
air, and sets an energy in form of expansive force free, by which the velocity of
escape is further increased.
Through a straight tube or an opening in the boiler, steam escapes into the air
with a pressure of one atmosphere; but if plates A B are suitably used, this
pressure will be much lower. If for example the boiler pressure is 10 atmospheres,
the density or pressure of the escaping steam will be only 0.29 atmosphere. It is
obvious that the entire energy of the boiler pressure as well as that, due to the
expansion from 10 to 0.29 atmosphere, becomes accumulated as vis inertia in the
current, producing in it a velocity of 3550 feet (= 1084 meter) per second. This
current has the form of a very thin disk, tending to increase its diameter in
the air.
In Fig. 1, are A and B the two plates, through which the steam escapes as
above stated. A has a hub a, in which is fitted the stud b of plate B; hub a is in
its inner part fluted, forming channels for leading the steam, entering through
tube E, towards the plates. Suitable arrangements are made, to adjust by hand
wheel d the distance between the plates A B, in order to regulate the quantity
of steam used.

page_text: KK are two discs, so situated in relation to A B, that the steam current passes
between, and that air can freely enter next A B, as indicated by arrows; the
area of the apertures for the entrance of the air can be regulated by circular
slides j j.
The entering air has an intense tendency to mix and diffuse with the steam,
whereby the inertia of the latter is transfered to the mixture, which is driven at
a reduced speed towards G, producing thereby a rarified space near A B, which
draws in the air by suction.
The admission of steam and air can both be regulated as above mentioned.
Supposing that for one pound of steam of 10 atmospheres, 40 pounds of air of
50 degrees Fahrenheit (=10° (.) are admitted; the mixture of air, steam and
condensed water (finely divided and suspended) will then escape at G with a
temperature of 86 degrees Fahrenheit (= 30° C.).
The air being heated from 50 to 86 degrees, is thereby expanded accordingly,
and a part of the steam condensed to water.
The entire energy set free by the steam hetween the plates A B and K K, is
theoretically the same as that, which would be produced by expanding it, until its
temperature is reduced from 437 degree (due to 10 atmosphere) to 86 degrees (the
temperature at G), or its pressure from 10 to atmosphere. The heat
transfered to the air between the plates K K, produces there the same inertia,
as if the steam had been expanded alone, until its temperature is reduced to
86 degrees.
Under the above proportions, the mixture obtains at the circumference of the
plates K K a velocity of 516 feet per second, which is about th of that of the
steam, escaping from the plates A B. It flows then through the guide plates L'
into the buckets of the turbine wheel, whose axis of rotation is in the centre of the
plates A B.
The above velocity of the mixture (= 516 feet per second) would require for a
turbine wheel of 20 inches active diameter about 3000 revolutions per minute,
which speed is still too high for general use. It can be further reduced, either by
increasing the proportion (1 to 40) between steam and air, or by using a serial-
turbine consisting of several circles of guide-plates and wheel buckets, through
which the mixture flows from one to the other, reducing thereby its speed
successively.
In Fig. 1 are L, L". L three guiding rings, connected together to the stan] II;
TTT are three bucket wheels, being cast in one, and fastened to shaft W,
hearing in stand Ii, and in a suitable support rot shown. The form and
arrangement of the guides L' L L and wheel buckets T T T are shown in
Fig. 4, which is a section through the circle, in Fig. 1, flatened ont straight.
The mixture flows first through the guides L' into the buckets "; then into the
guides L, in which its direction is reversed, to flow into the Buckets T, and
to on; from Tit passes into the circular space S, and through the escape-pipe S
into the air.
In the turbine, which thus rotates about 800 times per minute, the velocity
of the mixture is reduced from 516 to 100 feet per second, and the escaping
current in S contains only (18)² = 0.037 or 3.7 per cent. of the inertia, with
which it entered the guides L'; the turbine has taken up 96.3 per cent.
The ring L, containing the guides, is made in two sections, in order to place it
around the turbine wheel.
Figs. 5 and 6 show a modification of the turbine, arranged in radial direction,
with only one circle of guides L, and three bucket wheels, two of which, (T' and
Trotate in one direction, and one, (T") in the other. The form of the
Tuckets are shown in partial section in Fig. 6; the wheels T T are fastened to
the hollow shaft aud T to shaft W, one end of which bears within shaft r, as
shown in Fig. 5.
L'
The current passes from K K through the quities L into the buckets T; then
into those T", which rotate in opposite direction to T', as is indicated by arrows in

page_text: Fig. 6; then it passes into the buckets T, which rotate with T¹, from where it is
led oft through S and S¹.
This arrangement avoids the guides L" L₁ and allows the current to pass
through the several rows of buckets in a more straight direction. The power can
be transmitted from the two opposite rotating shafts and W in any suitable way.
The velocity of the escaping mixture may be also reduced by only one turbine
wheel T (Fig. 4) rotating between two circles of guides L' L", if the channels of
the wheel T are made conical, so that their areas are larger next to the guides Lu
than next to those L'. Shaping then the guide buckets L" less curved (that is to
say, in Fig. 4 more straight in horizontal direction) so as to produce some resistance
to the current, escaping from the wheel buckets T₁, a reacting force will thus be
produced, which drives the single wheel, and produces the same motive power, as
by the use of serial turbines. Fig. 1 shows channels T T conical.
A special
peculiarity of this invention consists in the very thin steam current, passing in the
form of a disc from the plates A. B into the space between KK. For a five horse
power motor this current will be only 6th part of an inch, the plates being
3 inches in diameter. The mixing of the steam with the air, and the transmission
of inertia to the air will therefore be perfect, the more so, as there is an intense
affinity between them. The steam escapes from the plates A B with a tension
much below that of the air (= 0.29 atmosphere) and will therefore be on both sides
of the disclike current acted on by the air, tending to compress it.
The current is
equally distributed towards the circle of guides.
The form of the current may be modified, so as to be conical instead flat, by
constructing the plates A B and K K accordingly. It may also consist of many
thin radial or conical jets.
It is obvious, that pressed or heated air or other gases (for example, coal gas,
previously burnt or exploded) can be used instead of steam according to this.
invention. The current can also act intermittent instead of continuous. Coal
gas can be pressed through the plates A B and ignited between K K. The air
(or another gas) may be pressed into the mixing space between K K by a pump or
any other contrivance.
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 :
1. A turbine driven on by steam or gas, combined with plates (A. B) or their
equivalents, from the circumference of which escapes the steam in radial direction
in form of a thin disc or a cone into a space, so constructed and arranged, that it
will mix with a large quantity of air, admitted into said space, and that its inertia
is transmitted at a reduced velocity to the mixture of steam and air, which is then
led through the turbine, and drives the same at a moderate speed, substantially as
herein set forth.
2. In combination with plates (A B) and a mixing space, a serial turbine,
having more than one row of turbine buckets, and whereby the driving current
of the mixture passes from one to the other row as herein set forth.
3. The double turbine with turbine wheels rotating in opposite directions, the
driving steam or mixture passing from one wheel to the other, without having
guides placed between them, substantially as herein described.
Dated thin 04ch dox of December 1801
LOUIS BOLLMANN.