Year: 1898

page_text: I, NILS SVENSSON BÖK, Engineer, of Bergsgatan 11 B, Stockholm, in the Kingdom
of Sweden, do hereby declare the nature of this invention to be as follows:-
The object of this invention is to collect, shape and direct more perfectly than
heretofore the driving-fluid of turbines driven by means of vapours, gases or
mixtures of both, so that its energy can be utilized by the turbine to a greater
extent and, by a change of its direction of motion, be used for braking or reversing
the motor.
In a convenient and simple form of the invention an expansion-passage is
employed which is continued by a bend in one piece with it, through which the
driving-fluid is conducted to the vanes of an axial turbine after having been
compelled by its own vis viva, during its passage through the said bend, to pass
along the concave surface of the bend and in so doing to fill the whole width of
the passage formed by the bend and its continuation, guide passage forming a
layer the thickness of which is approximately determined by the pressure of
admission. In the present case the expansion-passage has circular sections, while
the sections of the bend which collects the fluid, gradually change from circular
to rectangular ones with rounded corners, the latter sections in the guide-passage
succeeding the bend gradually passing into the shape of a fragment or section of
a circular ring. In the last section of the guide-passage the latter has the same,
or nearly the same dimension as the space opposite it between the vanes, measured
radially. The edge of the last section of the guide-passage at the end of the
aforesaid circular ring section, where the collected fluid flows through, should
be extended so far that no part of the fluid can escape being directed by it on
to the turnbine-wheel at the angle that the fluid should have with relation to the
direction of the first element of the vanes of the turbine.
In a modified construction the bend and guide-passage may be means of a
conical joint be connected with and communicate with the expansion-passage and
consequently by being rotated about the axis of the latter, can be reversed so that
the driving-fluid will strike the back of the vanes of the turbine, a braking, or
a reversal of the direction of motion, of the turbine being thus effected.
Or the direction of motion of the driving-fluid can be changed by shifting or

page_text: sliding a double section of the inlet passage or nozzle over to the right or left
so that either section will form the continuation of the passage.
If a similar change of direction is to be effected in the first described device
it is done by rotating the whole device around its axis.
In
It is evidently of importance that the driving-fluid in the last section of the
admission device be so shaped that when first admitted to the first element of
the vanes it will fill the entire radial width of the vane-space (in an axial turbine).
For, if this is not the case, the fluid, owing to its pressure on the surface of the
vane, must disperse on the vane while the latter is moving away from it.
this case the pressure of the fluid on the same surface is decreased by an amount
corresponding to the work spent in the said dispersion. Moreover, it is probable
that the losses are still further augmented by the eddies formed in the act of
dispersion.
That the last sectional shape, a portion or section of a circular ring, of the
admission-passage is better than an extended elliptical form produced by obliquely
cutting a cylindrical nozzle-piece, is very evident and can be easily shown.
Calculation shows that about 12.5% of the whole area of the ellipse falls on
the ends of the ellipse overlapping the ring-section, while evidently an equal
percentage of the area falling inside the ring-section is not taken up by the
ellipse.
This means that about 25% of the driving-fluid is, owing to the elliptical section
so unfavourably applied to the vanes of the turbine that it is forced to disperse
more or less (in the axial turbine radially inward and outward in the vane-spaces).
In addition to this, owing to the greater length of the ellipse, the dispersion
takes place in about 21.5% greater number of vane-spaces, accordingly under
This in the
more unfavourable conditions with regard to friction of the vanes.
case of full admission in an ordinary expansion-passage having a straight nozzle
of cylindrical cross-section.
The conditions will be still more unfavourable to such an expansion-passage
when the reduction of the pressure of admission of the fluid by the governor is
taken in consideration. For, in the straight expansion-passage one of the follow-
ing alternatives will then occur:
1. The driving fluid on completing its expansion will leave the conical wall
for instance, and approximately retaining its shape will enter between the vanes,
covering a reduced elliptic area, thus embracing a smaller number of spaces-
and also, in the same ratio a reduced width so that the dispersion in the spaces
between the vanes becomes still more considerable than in the case of full
admission: or
2. The velocity of the driving-fluid will decrease in the admission-passage in a
certain ratio, so that the passage will be completely filled and the fluid will enter
the turbine-wheel with increased velocity, covering the entire ellipse, in which
case the same disadvantages of dispersion and distribution over an equal number
of vane-spaces will obtain as in the case of full admission.
With a bent passage and the last section shaped as a section of a circular ring
of a height equalling the radial height of the vane-space, the driving fluid under
all circumstances flows along the concave wall of the bend at velocities approxi-
mately corresponding to the different pressures of admission; and since the radial
width of discharge of the driving fluid on to the vanes during the period of
admission if constant, the extent of space occupied by the fluid in the direction
of the periphery will be approximately proportional to the pressure of admission.
Thus, with this arrangement of passages the number of vane-spaces occupied
by the fluid is diminished in the same ratio as the pressure of admission is lowered
by the governor, or, in other words, the driving fluid in this case under all
conditions is properly collected and shaped--thus favouring the efficiency.
From the above it is also evident that the wall of the bend and of the guide-
passage or nozzle, which is situated opposite to that by which the conduction and
shaping of the fluid is effected, can be omitted without affecting the working,

page_text: and that consequently this portion of the passage can be made either open or
closed.
In order that the driving-fluid, even for the maximum reduction of the pressure
of admission, shall pass along that portion of the wall of the expansion passage
which passes over into the concave portion of the bend the expansion passage
may, be slightly curved, thus causing the fluid to occupy the desired portion of
the passage.
It will be evident without further explanation that, if the radial dimension
of the last section is made large in comparison with the tangential one, the form
of the said last section may be made quite rectangular.
1000
BOULT & WADE,
Agents for the Applicant.
I, NILS SVENSSON BÖK, Engineer, of Bergsgatan 11 B, Stockholm, in the Kingdom
of Sweden, 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 by means of vapours, gases or mixtures
of both, in which the operating fluid is expanded in the inlet channel or in the
channel leading to the turbine wheel, to the pressure of the turbine casing in
order to collect, shape and direct the operating fluid before it acts on the vanes
and by means of its own eis viva, so that its cis cica, in a higher degree than
before, can be used by the turbine and this power can also be utilized for the
object of braking or reversing the motion of the motor.
This invention especially relates to an arrangement or construction of that
part of the guide passage for the operating fluid, which is situated between the
part in the passage, where expansion takes place, and the turbine vanes, this part
being longitudinally bent or inclined for the purpose mentioned.
Figure 1 of the accompanying drawing shows by way of example an expansion-
passage a which is continued by a bend in one piece with it, through which the
driving fluid is conducted to the vanes of an axial turbine c after having been
compelled by its own vis viva, during its passage through the said bend, to pass
along the concave surface of the bend and in so doing to fill the whole width of
the passage formed by the bend and its continuation guide passage d, in a jet
the thickness of which is approximately determined by the pressure of admission.
In the case illustrated the expansion passage has a circular section, while the
sections of the bend b which collects the fluid gradually change from circular
to rectangular with rounded corners, the latter sections in the guide-passage d
succeeding the bend b gradually passing into the shape of a fragment or section
of a circular ring (see the sections CD EF e Figure 1). In the last section of
the guide-passage (at c) the latter has the same, or nearly the same, dimension
as the space opposite it between the vanes, measured radially. The edge of the
last section of the guide-passage d at the end of the aforesaid circular ring section,
where the collected fluid flows through, should be extended so far that no part
of the fluid can escape, being directed by it on to the turbine-wheel at the angle
that the fluid should have with relation to the direction of the first element f of
the vanes of the turbine.
In Figure 2 the bend b and guide-passage d by means of a conical joint com-

page_text: municate with the expansion-passage a and consequently by being rotated about
the axis A B can be reversed so that the driving fluid will strike the back of the
vanes of the turbine, a braking, or a reversal of the direction of motion, of the
turbine being thus effected. The dotted lines in Figure 2 show the position of
passage bd after the reversal.
In Figure 3 is indicated how the direction of motion of the driving-fluid can
be changed by shifting or sliding the double section bd of the passage over to
the right or left, so that the section bd or bid will form the continuation of
the passage a.
If a similar change of direction is to be effected in the passage in Figure 1 it
is done by rotating the whole device a, b and d around its axis A B.
In
It is evidently of importance that the driving-fluid in the last section of the
admission passage be so shaped that when first admitted to the first element of
the vanes it will fill the entire radial width of the vane-space (in an axial turbine).
For, if this is not the case, the fluid, owing to its pressure on the surface of the
vane, must disperse on the vane while the latter is moving away from it.
this case the pressure of the fluid on the same surface is decreased by an amount
corresponding to the work spent in the said dispersion. Moreover, it is probable
that the losses are still further augmented by tlie eddies formed in the act of
dispersion.
That the last sectional shape, a portion or section of a circular ring, of the
admission-passage is better than the extended elliptical form produced by obliquely
cutting a cylindrical nozzle-piece, is very evident from Fig. 4 where g, h, i, k,
shows a circular ring fragment of the same height as the ellipse l, m, n, o, when
both have the same area. In this Figure g, k, is equal to the radial width of the
vane space.
Calculation shows that about 12.5% of the whole area of the ellipse falls on
the ends of the ellipse overlapping the ring-section, while evidently an equal
percentage of the area falling inside the ring-section is not taken up by the
ellipse.
This means that about 25% of the driving-fluid is, owing to the elliptical section,
so unfavourably applied to the vanes of the turbine that it is forced to disperse
more or less (in the axial turbine radially inwards and outwards in the vane-
spaces).
In addition to this, owing to the greater length of the ellipse, the dispersion
takes place in about 21.5% greater number of vane-spaces, accordingly under
more unfavourable conditions with regard to friction of the vanes. This in the
case of full admission in an ordinary expansion-passage having a straight nozzle
of cylindrical cross-section.
The conditions will be still more unfavourable to such an expansion-passage
when the reduction of the pressure of admission of the fluid by the governor is
taken in consideration. For, in the straight expansion-passage one of the follow-
ing alternatives will then occur.
1. The driving-fluid on completing its expansion (as indicated by dotted lines
in Figure 5) will leave the conical wall at the section p, for instance, and approxi-
mately retaining its shape will enter between the vanes, covering an elliptical
area grst (see Figure 4) which has been reduced to the length -s, thus embracing
a smaller number of spaces--and also, in the same ratio, to the width r-t, so that
the dispersion in the spaces between the vanes becomes still more considerable
than in the case of full admission; or
2. The velocity of the driving-fluid will decrease in the admission-passage in
the same ratio as the section at p', is greater than that at p. so that the passage
will be completely filled and the fluid will enter the turbine-wheel with increased
velocity, covering the entire ellipse 7 m n o, in which case the same disadvan-
tages of dispension and distribution over an equal number of vane-spaces will
obtain as in the case of full admission.
With a bent passage and the last section shaped as a section of a circular ring

page_text: of a height equalling the radial height of the vane-space, the driving fluid under
all circumstances flows along the concave wall of the bend at velocities approxi-
mately corresponding to the different pressures of admission; and since the radial
width of discharge of the driving fluid on to the vanes during the period of
admission is constant (h), the extent of space occupied by the fluid in the direction
of the periphery will be approximately proportional to the pressure of admission.
Thus, for instance, in Figure 4 the ellipse qrst is equal in size to the circular
ring, section u hit which indicates the shape of the vane-surface occupied by the
driving fluid when the same fluid is admitted to the turbine by a bent passage
and for the same reduction in the pressure of admission as has been assumed to
take place in Figure 5 (dotted lines).
Thus, with this arrangement of passages the number of vane-spaces occupied
by the fluid is diminished in the same ratio as the pressure of admission is lowered
by the governor, or, in other words, the driving fluid in this case under all
conditions is properly collected and directed-thus favouring the efficiency.
From the above it is also evident that the wall of the bend and of the guide-
passage or nozzle, which is situated opposite to that by which the entry and
shaping of the fluid is effected, can be omitted without affecting the working,
and that consequently this portion of the passage can be made either open or
closed.
In order that the driving-fluid, even for the maximum reduction of the pressure
of admission, shall pass along that portion of the wall of the expansion-passage a
which merges into the concave portion of the bend b, the expansion-passage a
may, as in Figure 6, be slightly curved, thus causing the fluid to occupy the
cross-hatched portion of the passage in Figure 6.
It will be evident without further explanation that, if the radial dimension
of the last section (at e) is made large in comparison with the tangential one, the
form of the said last section may be made quite rectangular.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
1. In inlet conduits for turbines driven by vapours or gases or mixtures thereof,
in which conduits an expansion of the driving fluid down to the pressure in the
turbine-casing takes place, the arrangement that that part of the admission passage,
which is situated between the expansion-place and the turbine wheel (or in multiple
turbines the first turbine wheel), is inclined so that the driving fluid by means
of its own vis viva, may be collected, shaped and directed before the inlet to the
turbine vanes by the concave part of the bend, substantially as described.
2. In admission conduits for turbines of the kind described the arrangement
of the inclined part of the admission conduit as a separate piece, which can be
turned around the axes of the admission passage or be moved transversely to the
same (in the latter case the part containing two passages, directed in different direc-
tions), substantially as described.
3. Admission conduits for turbines of the kind described in which the bent
part forms an open or closed passage, with a constant area, the sections of said
passage changing gradually from a circular form to the form of a sectional segment
of a circular ring or a rectangle, substantially as described.
4. An admission conduit for turbines substantially as described or illustrated
in Figure 1 or in Figure 2 or in Figure 3 of the accompanying drawings.
1000
BOULT & WADE,
Agents for the Applicant.