U.S. patent application number 10/489914 was filed with the patent office on 2005-02-10 for rotary fluid machine.
Invention is credited to Endoh, Tsuneo, Ichikawa, Hiroshi, Kimura, Yasunari, Takahashi, Tsutomu.
Application Number | 20050031479 10/489914 |
Document ID | / |
Family ID | 19111886 |
Filed Date | 2005-02-10 |
United States Patent
Application |
20050031479 |
Kind Code |
A1 |
Takahashi, Tsutomu ; et
al. |
February 10, 2005 |
Rotary fluid machine
Abstract
A rotary fluid machine is provided that includes a rotor chamber
(14) formed in a casing, a rotor (41) rotatably housed within the
rotor chamber (14), a plurality of vane channels (49) formed
radially in the rotor (41), a plurality of vanes (48) slidably
supported in the respective vane channels (49), vane chambers (75)
defined between adjacent vanes (48), and an intake port (90) and an
exhaust port (91) for supplying and discharging a gas-phase working
medium to and from the vane chambers (75). A labyrinth (43g)
provided on the outer peripheral face of the rotor (41) prevents
the gas-phase working medium from leaking in a region in which
there is a large difference in pressure between adjacent vane
chambers (75) that are in between the trailing edge of the exhaust
port (91) and the leading edge of the intake port (90).
Inventors: |
Takahashi, Tsutomu;
(Saitama, JP) ; Endoh, Tsuneo; (Saitama, JP)
; Ichikawa, Hiroshi; (Saitama, JP) ; Kimura,
Yasunari; (Saitama, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
19111886 |
Appl. No.: |
10/489914 |
Filed: |
October 4, 2004 |
PCT Filed: |
September 20, 2002 |
PCT NO: |
PCT/JP02/09720 |
Current U.S.
Class: |
418/104 |
Current CPC
Class: |
F01B 13/068 20130101;
F04C 18/3446 20130101; F01B 13/06 20130101; F01C 21/08 20130101;
F02B 53/00 20130101; F01C 21/0872 20130101; F01B 13/061 20130101;
F01C 21/0836 20130101; F01C 1/3446 20130101; F01C 21/0881 20130101;
F01C 21/04 20130101; F01C 19/02 20130101; F04C 27/001 20130101 |
Class at
Publication: |
418/104 |
International
Class: |
F01C 019/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 21, 2001 |
JP |
2001-289388 |
Claims
What is claimed is:
1. A rotary fluid machine comprising a rotor chamber (14) formed in
a casing (11), a rotor (41) rotatably housed within the rotor
chamber (14), a plurality of vane channels (49) formed radially in
the rotor (41), a plurality of vanes (48) slidably supported in the
respective vane channels (49), vane chambers (75) defined by the
rotor (41), the casing (11), and the vanes (48), and an intake port
(90) and an exhaust port (91) for supplying and discharging a
gas-phase working medium to and from the vane chambers (75);
characterized in that gas-phase working medium leakage preventing
means is provided on at least one of the outer peripheral face of
the rotor (41) and the inner peripheral face of the rotor chamber
(14) in a region in which there is a large difference in pressure
between adjacent vane chambers (75) that are in between the
trailing edge of the exhaust port (91) and the leading edge of the
intake port (90).
2. The rotary fluid machine according to claim 1, wherein the
leakage preventing means is a labyrinth (43g).
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a rotary fluid machine for
interconverting the pressure energy of a gas-phase working medium
and the rotational energy of a rotor.
BACKGROUND ART
[0002] A rotary fluid machine disclosed in Japanese Patent
Application Laid-open No. 2000-320543 is equipped with a vane
piston unit in which a vane and a piston are combined; the piston,
which is slidably fitted in a cylinder provided radially in a
rotor, interconverts the pressure energy of a gas-phase working
medium and the rotational energy of the rotor via a power
conversion device comprising an annular channel and a roller, and
the vane, which is radially and slidably supported in the rotor,
interconverts the pressure energy of the gas-phase working medium
and the rotational energy of the rotor.
[0003] Such a rotary fluid machine comprises an elliptical rotor
chamber formed in a casing and a circular rotor rotatably housed
within the rotor chamber, and by setting the diameter of the rotor
substantially equal to the minor axis of the rotor chamber, the
clearance between the rotor and the rotor chamber becomes a minimum
at positions at opposite ends of the minor axis. An intake port and
an exhaust port are provided on either side, circumferentially, of
these minimum clearance positions, and leakage of a gas-phase
working medium from a high pressure vane chamber, with which the
intake port communicates, into a low pressure vane chamber, with
which the exhaust port communicates, is prevented by making a seal
at the extremity of the vane abut against the inner peripheral face
of the rotor chamber. However, it is difficult to completely
prevent the leakage of the gas-phase working medium using only the
seal at the extremity of the vane, and there is the problem that
the gas-phase working medium leaks between vane chambers having
different pressures, thus degrading the performance of the rotary
fluid machine.
DISCLOSURE OF THE INVENTION
[0004] The present invention has been achieved under the
above-mentioned circumstances, and an object thereof is to prevent
leakage of a gas-phase working medium from an intake port to an
exhaust port via a clearance between a rotor and a rotor chamber of
a rotary fluid machine.
[0005] In order to attain the above object, in accordance with a
first aspect of the present invention, there is proposed a rotary
fluid machine that includes a rotor chamber formed in a casing, a
rotor rotatably housed within the rotor chamber, a plurality of
vane channels formed radially in the rotor, a plurality of vanes
slidably supported in the respective vane channels, vane chambers
defined by the rotor, the casing, and the vanes, and an intake port
and an exhaust port for supplying and discharging a gas-phase
working medium to and from the vane chambers, characterized in that
gas-phase working medium leakage preventing means is provided on at
least one of the outer peripheral face of the rotor and the inner
peripheral face of the rotor chamber in a region in which there is
a large difference in pressure between adjacent vane chambers that
are in between the trailing edge of the exhaust port and the
leading edge of the intake port.
[0006] In accordance with this arrangement, since the gas-phase
working medium leakage preventing means is provided on at least one
of the outer peripheral face of the rotor and the inner peripheral
face of the rotor chamber in a region in which there is a large
difference in pressure between adjacent vane chambers that are in
between the trailing edge of the exhaust port and the leading edge
of the intake port, it is possible to prevent the gas-phase working
medium from leaking from the intake port, which is at high
pressure, to the exhaust port, which is at low pressure, thereby
improving the performance of the rotary fluid machine.
[0007] Furthermore, in accordance with a second aspect of the
present invention, in addition to the first aspect, there is
proposed a rotary fluid machine wherein the leakage preventing
means is a labyrinth.
[0008] In accordance with this arrangement, since the leakage
preventing means is formed from a labyrinth, a problem such as seal
wear, which occurs when the leakage preventing means is formed from
a seal, can be avoided.
[0009] Labyrinths 43g of embodiments correspond to the leakage
preventing means of the present invention, and steam and water of
the embodiments correspond to the gas-phase working medium and the
liquid-phase working medium respectively of the present
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 to FIG. 18 illustrate a first-embodiment of the
present invention;
[0011] FIG. 1 is a schematic view of a waste heat recovery system
of an internal combustion engine;
[0012] FIG. 2 is a longitudinal sectional view of an expander,
corresponding a sectional view along line 2-2 of FIG. 4;
[0013] FIG. 3 is an enlarged sectional view around the axis of FIG.
2;
[0014] FIG. 4 is a sectional view along line 4-4 of FIG. 2;
[0015] FIG. 5 is a sectional view along line 5-5 of FIG. 2;
[0016] FIG. 6 is a sectional view along line 6-6 of FIG. 2;
[0017] FIG. 7 is a sectional view along line 7-7 of FIG. 5;
[0018] FIG. 8 is a sectional view along line 8-8 of FIG. 5;
[0019] FIG. 9 is a sectional view along line 9-9 of FIG. 8;
[0020] FIG. 10 is a sectional view along line 10-10 of FIG. 3;
[0021] FIG. 11 is an exploded perspective view of a rotor;
[0022] FIG. 12 is an exploded perspective view of a lubricating
water distribution section of the rotor;
[0023] FIG. 13 is a schematic view showing cross-sectional shapes
of a rotor chamber and the rotor;
[0024] FIG. 14A is a view showing the shape of an annular channel
of a casing (embodiment);
[0025] FIG. 14B is a view showing the shape of an annular channel
of a casing (conventional example);
[0026] FIG. 15A is a view showing the shape of the inner peripheral
face of a rotor chamber and the intake and exhaust timing
(embodiment);
[0027] FIG. 15B is a view showing the shape of the inner peripheral
face of a rotor chamber and the intake and exhaust timing
(conventional example); and
[0028] FIG. 16 to FIG. 18 are views for explaining the operation of
labyrinths.
[0029] FIG. 19 to FIG. 21 are views for explaining the operation of
labyrinths of a second embodiment of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0030] A first embodiment of the present invention is explained
below with reference to FIG. 1 to FIG. 18.
[0031] In FIG. 1, a waste heat recovery system 2 for an internal
combustion engine 1 includes an evaporator 3 that generates high
temperature, high pressure steam by vaporizing a high pressure
liquid (e.g. water) using as a heat source the waste heat (e.g.
exhaust gas) of the internal combustion engine 1, an expander 4
that generates an output by expansion of the steam, a condenser 5
that liquefies steam having decreased temperature and pressure as a
result of conversion of pressure energy into mechanical energy in
the expander 4, and a supply pump 6 that pressurizes the liquid
(e.g. water) from the condenser 5 and resupplies it to the
evaporator 3.
[0032] As shown in FIG. 2 and FIG. 3, a casing 11 of the expander 4
is formed from first and second casing halves 12 and 13, which are
made of metal. The first and second casing halves 12 and 13 are
formed from main body portions 12a and 13a, which in cooperation
form a rotor chamber 14, and circular flanges 12b and 13b, which
are joined integrally to the outer peripheries of the main body
portions 12a and 13a, and the two circular flanges 12b and 13b are
joined together via a metal gasket 15. The outer face of the first
casing half 12 is covered with a transit chamber outer wall 16
having a deep bowl shape, and a circular flange 16a, which is
joined integrally to the outer periphery of the transit chamber
outer wall 16, is superimposed on the left face of the circular
flange 12b of the first casing half 12. The outer face of the
second casing half 13 is covered with an exhaust chamber outer wall
17 for housing a magnet coupling (not illustrated) for transmitting
the output of the expander 4 to the outside, and a circular flange
17a, which is joined integrally to the outer periphery of the
exhaust chamber outer wall 17, is superimposed on the right face of
the circular flange 13b of the second casing half 13. The
above-mentioned four circular flanges 12b, 13b, 16a, and 17a are
tightened together by means of a plurality of bolts 18 disposed in
the circumferential direction. A transit chamber 19 is defined
between the transit chamber outer wall 16 and the first casing half
12, and an exhaust chamber 20 is defined between the exhaust
chamber outer wall 17 and the second casing half 13. The exhaust
chamber outer wall 17 is provided with an outlet (not illustrated)
for guiding the decreased temperature, decreased pressure steam
that has finished work in the expander 4 to the condenser 5.
[0033] The main body portions 12a and 13a of the two casing halves
12 and 13 have hollow bearing tubes 12c and 13c projecting outward
in the lateral direction, and a rotating shaft 21 having a hollow
portion 21 a is rotatably supported by these hollow bearing tubes
12c and 13c via a pair of bearing members 22 and 23. The axis L of
the rotating shaft 21 thus passes through the intersection of the
major axis and the minor axis of the rotor chamber 14, which has a
substantially elliptical shape.
[0034] A seal block 25 is housed within a lubricating water supply
member 24 screwed onto the right-hand end of the second casing half
13, and secured by a nut 26. A small diameter portion 21b at the
right-hand end of the rotating shaft 21 is supported within the
seal block 25, a pair of seals 27 are disposed between the seal
block 25 and the small diameter portion 21b, a pair of seals 28 are
disposed between the seal block 25 and the lubricating water supply
member 24, and a seal 29 is disposed between the lubricating water
supply member 24 and the second casing half 13. A filter 30 is
fitted in a recess formed in the outer periphery of the hollow
bearing tube 13c of the second casing half 13, and is prevented
from falling out by means of a filter cap 31 screwed into the
second casing half 13. A pair of seals 32 and 33 are provided
between the filter cap 31 and the second casing half 13.
[0035] As is clear from FIG. 4, FIG. 13, FIG. 14A, and FIG. 14B, a
circular rotor 41 is rotatably housed within the rotor chamber 14,
which has a pseudo-elliptical shape. The rotor 41 is fitted onto
and joined integrally to the outer periphery of the rotating shaft
21, and the axis of the rotor 41 and the axis of the rotor chamber
14 coincide with the axis L of the rotating shaft 21. The shape of
the rotor chamber 14 viewed in the axis L direction is
pseudo-elliptical, and is similar to a rhombus with its four apexes
rounded, the shape having a major axis DL and a minor axis DS. The
shape of the rotor 41 viewed in the axis L direction is a perfect
circle having a diameter DR that is slightly smaller than the minor
axis DS of the rotor chamber 14.
[0036] The cross-sectional shapes of the rotor chamber 14 and the
rotor 41 viewed in a direction orthogonal to the axis L are all
racetrack-shaped. That is, the cross-sectional shape of the rotor
chamber 14 is formed from a pair of flat faces 14a extending
parallel to each other at a distance d, and arc-shaped faces 14b
having a central angle of 180.degree. that are smoothly connected
to the outer peripheries of the flat faces 14a and, similarly, the
cross-sectional shape of the rotor 41 is formed from a pair of flat
faces 41a extending parallel to each other at the distance d, and
arc-shaped faces 41b having a central angle of 180.degree. that are
smoothly connected to the outer peripheries of the flat faces 41a.
The flat faces 14a of the rotor chamber 14 and the flat faces 41a
of the rotor 41 are in contact with each other, and a pair of
crescent-shaped spaces are formed between the inner peripheral face
of the rotor chamber 14 and the outer peripheral face of the rotor
41 (see FIG. 4).
[0037] The structure of the rotor 41 is now explained in detail
with reference to FIG. 3 to FIG. 6, and FIG. 11.
[0038] The rotor 41 is formed from a rotor core 42 that is formed
integrally with the outer periphery of the rotating shaft 21, and
twelve rotor segments 43 that are fixed so as to cover the
periphery of the rotor core 42 and form the outer shell of the
rotor 41. Twelve ceramic (or carbon) cylinders 44 are mounted
radially in the rotor core 42 at 300 intervals and fastened by
means of clips 45 to prevent them falling out. A small diameter
portion 44a is projectingly provided at the inner end of each of
the cylinders 44, and a gap between the base end of the small
diameter portion 44a and a sleeve 84 is sealed via a C seal 46. The
extremity of the small diameter portion 44a is fitted into the
outer peripheral face of the sleeve 84, which is hollow, and a
cylinder bore 44b communicates with first and second steam passages
S1 and S2 within the rotating shaft 21 via twelve third steam
passages S3 running through the small diameter portion 44a and the
rotating shaft 21. A ceramic piston 47 is slidably fitted within
each of the cylinders 44. When the piston 47 moves to the radially
innermost position, it retracts completely within the cylinder bore
44b, and when it moves to the radially outermost position, about
half of the whole length projects outside the cylinder bore
44b.
[0039] Each of the rotor segments 43 is a hollow wedge-shaped
member having a central angle of 30.degree., and has two recesses
43a and 43b formed on the faces thereof that are opposite the pair
of flat faces 14a of the rotor chamber 14, the recesses 43a and 43b
extending in an arc shape with the axis L as the center, and
lubricating water outlets 43c and 43d open in the middle of the
recesses 43a and 43b. Furthermore, four lubricating water outlets
43e and 43f open on the end faces of the rotor segments 43, that
is, the faces that are opposite vanes 48, which will be described
later. A large number of labyrinths 43g are recessed in the
arc-shaped face of each of the rotor segments 43 forming the
arc-shaped face 41b of the rotor 41 so as to extend within a plane
containing the axis L. The labyrinths 43g are channels having a
U-shaped cross section and, for example, sixteen of the labyrinths
43g are provided on each of the rotor segments 43.
[0040] The rotor 41 is assembled as follows. The twelve rotor
segments 43 are fitted around the outer periphery of the rotor core
42, which is preassembled with the cylinders 44, the clips 45, and
the C seals 46, and the vanes 48 are fitted in twelve vane channels
49 formed between adjacent rotor segments 43. At this point, in
order to form a predetermined clearance between the vanes 48 and
the rotor segments 43, shims having a predetermined thickness are
disposed on opposite faces of the vanes 48. In this state, the
rotor segments 43 and the vanes 48 are tightened inward in the
radial direction toward the rotor core 42 by means of a jig so as
to precisely position the rotor segments 43 relative to the rotor
core 42, and each of the rotor segments 43 is then provisionally
retained on the rotor core 42 by means of provisional retention
bolts 50 (see FIG. 8). Subsequently each of the rotor segments 43
and the rotor core 42 are co-machined so as to make two knock pin
holes 51 run therethrough, and four knock pins 52 are press-fitted
in the two knock pin holes 51 so as to join each of the rotor
segments 43 to the rotor core 42.
[0041] As is clear from FIG. 8, FIG. 9, and FIG. 12, a through hole
53 running through the rotor segment 43 and the rotor core 42 is
formed between the two knock pin holes 51, and recesses 54 are
formed at opposite ends of the through hole 53. Two pipe members 55
and 56 are fitted within the through hole 53 via seals 57 to 60,
and an orifice-forming plate 61 and a lubricating water
distribution member 62 are fitted into each of the recesses 54 and
secured by a nut 63. The orifice-forming plate 61 and the
lubricating water distribution member 62 are prevented from
rotating relative to the rotor segments 43 by two knock pins 64
running through knock pin holes 61a of the orifice-forming plate 61
and fitted into knock pin holes 62a of the lubricating water
distribution member 62, and a gap between the lubricating water
distribution member 62 and the nut 63 is sealed by an O ring
65.
[0042] A small diameter portion 55a formed in an outer end portion
of one of the pipe members 55 communicates with a sixth water
passage W6 within the pipe member 55 via a through hole 55b, and
the small diameter portion 55a also communicates with a radial
distribution channel 62b formed on one side face of the lubricating
water distribution member 62. The distribution channel 62b of the
lubricating water distribution member 62 extends in six directions,
and the extremities thereof communicate with six orifices 61b, 61c,
and 61d of the orifice-forming plate 61. The structures of the
orifice-forming plate 61, the lubricating water distribution member
62, and the nut 63 provided at the outer end portion of the other
pipe member 56 are identical to the structures of the
above-mentioned orifice-forming plate 61, lubricating water
distribution member 62, and nut 63.
[0043] Downstream sides of the two orifices 61b of the
orifice-forming plate 61 communicate with the two lubricating water
outlets 43e, which open so as to be opposite the vane 48, via
seventh water passages W7 formed within the rotor segments 43;
downstream sides of the two orifices 61c communicate with the two
lubricating water outlets 43f, which open so as to be opposite the
vane 48, via eighth water passages W8 formed within the rotor
segment 43; and downstream sides of the two orifices 61d
communicate with the two lubricating water outlets 43c and 43d,
which open so as to be opposite the rotor chamber 14, via ninth
water passages W9 formed within the rotor segment 43.
[0044] As is clear from reference in addition to FIG. 5, an annular
channel 67 is defined by a pair of O rings 66 on the outer
periphery of the cylinder 44, and the sixth water passage W6 formed
within said one of the pipe members 55 communicates with the
annular channel 67 via four through holes 55c running through the
pipe member 55 and a tenth water passage W10 formed within the
rotor core 42. The annular channel 67 communicates with sliding
surfaces of the cylinder bore 44b and the piston 47 via an orifice
44c. The position of the orifice 44c of the cylinder 44 is set so
that it stays within the sliding surface of the piston 47 when the
piston 47 moves between top dead center and bottom dead center.
[0045] As is clear from FIG. 3 and FIG. 9, the first water passage
W1 formed in the lubricating water supply member 24 communicates
with the small diameter portion 55a of said one of the pipe members
55 via a second water passage W2 formed in the seal block 25, third
water passages W3 formed in the small diameter portion 21b of the
rotating shaft 21, an annular channel 68a formed in the outer
periphery of a water passage forming member 68 fitted in the center
of the rotating shaft 21, a fourth water passage W4 formed in the
rotating shaft 21, a pipe member 69 bridging the rotor core 42 and
the rotor segments 43, and fifth water passages W5 formed so as to
bypass the knock pin 52 on the radially inner side of the rotor
segment 43.
[0046] As shown in FIG. 7, FIG. 9, and FIG. 11, twelve vane
channels 49 are formed between adjacent rotor segments 43 of the
rotor 41 so as to extend in the radial direction, and the
plate-shaped vanes 48 are slidably fitted in the respective vane
channels 49. Each of the vanes 48 has a substantially U-shaped form
comprising parallel faces 48a following the parallel faces 14a of
the rotor chamber 14, an arc-shaped face 48b following the
arc-shaped face 14b of the rotor chamber 14, and a notch 48c
positioned between the parallel faces 48a. Rollers 71 having a
roller bearing structure are rotatably supported on a pair of
support shafts 48d projecting from the parallel faces 48a.
[0047] A U-shaped synthetic resin seal 72 is retained in the
arc-shaped face 48b of the vane 48, and the extremity of the seal
72 projects slightly from the arc-shaped face 48b of the vane 48
and comes into sliding contact with the arc-shaped face 14b of the
rotor chamber 14. Two recesses 48e are formed on each side of the
vane 48, and these recesses 48e are opposite the two radially inner
lubricating water outlets 43e that open on the end faces of the
rotor segment 43. A piston receiving member 73, which is provided
so as to project radially inward in the middle of the notch 48c of
the vane 48, abuts against the radially outer end of the piston
47.
[0048] As is clear from FIG. 4, two pseudo-elliptical annular
channels 74 having a similar shape to that of a rhombus with its
four apexes rounded are provided in the flat faces 14a of the rotor
chamber 14 defined by the first and second casing halves 12 and 13,
and the pair of rollers 71 of each of the vanes 48 are rollably
engaged with these annular channels 74. The distance between these
annular channels 74 and the arc-shaped face 14b of the rotor
chamber 14 is constant throughout the whole circumference.
Therefore, when the rotor 41 rotates, the vane 48 having the
rollers 71 guided by the annular channels 74 reciprocates radially
within the vane channel 49, and the seal 72 mounted on the
arc-shaped face 48b of the vane 48 slides along the arc-shaped face
14b of the rotor chamber 14 with a constant amount of compression.
This enables direct physical contact between the rotor chamber 14
and the vanes 48 to be prevented and vane chambers 75 defined
between adjacent vanes 48 to be reliably sealed while preventing
any increase in the sliding resistance or the occurrence of
wear.
[0049] As is clear from FIG. 2, a pair of circular seal channels 76
are formed in the flat faces 14a of the rotor chamber 14 so as to
surround the outside of the annular channels 74. A pair of ring
seals 79 equipped with two O rings 77 and 78 are slidably fitted in
the circular seal channels 76, and the seal surfaces are opposite
the recesses 43a and 43b (see FIG. 4) formed in each of the rotor
segments 43. The pair of ring seals 79 are prevented from rotating
relative to the first and second casing halves 12 and 13 by knock
pins 80.
[0050] As is clear from FIG. 2, FIG. 3, and FIG. 10, an opening 16b
is formed at the center of the transit chamber outer wall 16; a
boss portion 81a of a fixed shaft support member 81 disposed on the
axis L is secured to the inner face of the opening 16b by a
plurality of bolts 82, and secured to the first casing half 12 by
means of a nut 83. A cylinder-shaped ceramic sleeve 84 is fixed to
the hollow portion 21a of the rotating shaft 21. The outer
peripheral face of the fixed shaft 85, which is integral with the
fixed shaft support member 81, is relatively rotatably fitted
within the inner peripheral face of this sleeve 84. A gap between
the left-hand end of the fixed shaft 85 and the first casing half
12 is sealed by a seal 86, and a gap between the right-hand end of
the fixed shaft 85 and the rotating shaft 21 is sealed by a seal
87.
[0051] A steam supply pipe 88 is fitted into the fixed shaft
support member 81, which is disposed on the axis L, and is secured
by a nut 89, and the right-hand end of the steam supply pipe 88 is
press-fitted into the center of the fixed shaft 85. The first steam
passage S1, which communicates with the steam supply pipe 88, is
formed in the center of the fixed shaft 85 in the axial direction,
and the pair of second steam passages S2 run radially through the
fixed shaft 85 with a phase difference of 180.degree.. As described
above, the twelve third steam passages S3 run through the sleeve 84
and the small diameter portions 44a of the twelve cylinders 44
retained at intervals of 30.degree. in the rotor 41 fixed to the
rotating shaft 21, and radially inner end portions of these third
steam passages S3 are opposite the radially outer end portions of
the second steam passages S2 so as to be able to communicate
therewith.
[0052] A pair of notches 85a are formed on the outer peripheral
face of the fixed shaft 85 with a phase difference of 180.degree.,
and these notches 85a can communicate with the third steam passages
S3. The notches 85a and the transit chamber 19 communicate with
each other via a pair of fourth steam passages S4 formed axially in
the fixed shaft 85, a fifth annular steam passage S5 formed axially
in the fixed shaft support member 81, and through holes 81b opening
on the outer periphery of the boss portion 81a of the fixed shaft
support member 81.
[0053] As shown in FIG. 2 and FIG. 4, a plurality of radially
aligned intake ports 90 are formed in the first casing half 12 and
the second casing half 13 at positions that are advanced by
15.degree. in the direction of rotation R of the rotor 41 relative
to the minor axis of the rotor chamber 14. The interior space of
the rotor chamber 14 communicates with the transit chamber 19 by
means of these intake ports 90. Furthermore, a plurality of exhaust
ports 91 are formed in the second casing half 13 at positions that
are retarded by 15.degree. to 75.degree. in the direction of
rotation R of the rotor 41 relative to the minor axis of the rotor
chamber 14. The interior space of the rotor chamber 14 communicates
with the exhaust chamber 20 by means of these exhaust ports 91.
These exhaust ports 91 open in shallow depressions 13d formed
within the second casing half 13 so that the seals 72 of the vanes
48 are not damaged by the edges of the exhaust ports 91.
[0054] The second steam passages S2 and the third steam passages
S3, and the notches 85a of the fixed shaft 85 and the third steam
passages S3, form a rotary valve V, which provides periodic
communication therebetween by rotation of the rotating shaft 21
relative to the fixed shaft 85 (see FIG. 10).
[0055] As is clear from FIG. 2, pressure chambers 92 are formed at
the rear face of the ring seals 79 fitted in the circular seal
channels 76 of the first and second casing halves 12 and 13. An
eleventh water passage W11 formed in the first and second casing
halves 12 and 13 communicates with the two pressure chambers 92 via
a twelfth water passage W12 and a thirteenth water passage W13,
which are formed from pipes, and the ring seals 79 are urged toward
the side face of the rotor 41 by virtue of water pressure applied
to the two pressure chambers 92.
[0056] The eleventh water passage W11 communicates with the outer
peripheral face of the annular filter 30 via a fourteenth water
passage W14, which is a pipe, and the inner peripheral face of the
filter 30 communicates with a sixteenth water passage W16 formed in
the second casing half 13 via a fifteenth water passage W15 formed
in the second casing half 13. Water supplied to the sixteenth water
passage W16 lubricates sliding surfaces of the fixed shaft 85 and
the sleeve 84. Water supplied to the outer periphery of the bearing
member 23 from the inner peripheral face of the filter 30 via a
seventeenth water passage W17 lubricates the outer peripheral face
of the rotating shaft 21 through an orifice penetrating the bearing
members 23. On the other hand, water supplied to the outer
periphery of the bearing members 22 from the eleventh water passage
W11 via an eighteenth water passage W18, which is a pipe,
lubricates the outer peripheral face of the rotating shaft 21
through an orifice penetrating the bearing member 22, and then
lubricates the sliding surfaces between the fixed shaft 85 and the
sleeve 84.
[0057] Operation of the present embodiment having the
above-mentioned arrangement is now explained.
[0058] Operation of the expander 4 is first explained. In FIG. 3,
high temperature, high pressure steam from the evaporator 3 is
supplied to the steam supply pipe 88, the first steam passage S1
passing through the center of the fixed shaft 85, and the pair of
second steam passages S2 passing radially through the fixed shaft
85. In FIG. 10, when the sleeve 84 that rotates integrally with the
rotor 41 and the rotating shaft 21 in the direction shown by the
arrow R reaches a predetermined phase relative to the fixed shaft
85, the pair of third steam passages S3 that are present on the
advanced side in the direction of rotation R of the rotor 41
relative to the position of the minor axis of the rotor chamber 14
are made to communicate with the pair of second steam passages S2,
and the high temperature, high pressure steam of the second steam
passages S2 is supplied to the interiors of a pair of the cylinders
44 via the third steam passages S3 and pushes the pistons 47
radially outward. In FIG. 4, when the vanes 48 pushed by the
pistons 47 move radially outward, since the pair of rollers 71
provided on the vanes 48 are engaged with the annular channels 74,
the forward movement of the pistons 47 is converted into rotational
movement of the rotor 41.
[0059] Even after the communication between the second steam
passages S2 and the third steam passages S3 is blocked as a result
of the rotation of the rotor 41, the high temperature, high
pressure steam within the cylinders 44 continues to expand, thus
making the pistons 47 move further forward and thereby enabling the
rotor 41 to continue to rotate. When the vanes 48 reach the
position of the major axis of the rotor chamber 14, the third steam
passages S3 communicating with the corresponding cylinders 44 also
communicate with the notches 85a of the fixed shaft 85, the pistons
47 are pushed by the vanes 48 whose rollers 71 are guided by the
annular channels 74 and move radially inward, and the steam within
the cylinders 44 accordingly passes through the third steam
passages S3, the notches 85a, the fourth passages S4, the fifth
passage S5, and the through holes 81b, and is supplied to the
transit chamber 19 as a first decreased temperature, decreased
pressure steam. The first decreased temperature, decreased pressure
steam is the high temperature, high pressure steam that has been
supplied from the steam supply pipe 88, has finished the work of
driving the pistons 47 and, as a result, has a decreased
temperature and pressure. The thermal energy and the pressure
energy of the first decreased temperature, decreased pressure steam
are lower than those of the high temperature, high pressure steam,
but are still sufficient for driving the vanes 48.
[0060] The first decreased temperature, decreased pressure steam
within the transit chamber 19 is supplied to the vane chambers 75
within the rotor chamber 14 via the intake ports 90 of the first
and second casing halves 12 and 13, and further expands therein to
push the vanes 48, thus rotating the rotor 41. A second decreased
temperature, decreased pressure steam that has finished work and
accordingly has a further decreased temperature and pressure is
discharged from the exhaust ports 91 of the second casing half 13
into the exhaust chamber 20, and is supplied therefrom to the
condenser 5.
[0061] In this way, the expansion of the high temperature, high
pressure steam enables the twelve pistons 47 to operate in turn to
rotate the rotor 41 via the rollers 71 and the annular channels 74,
and the expansion of the first decreased temperature, decreased
pressure steam, which is the high temperature, high pressure steam
whose temperature and pressure have decreased, enables the rotor 41
to rotate via the vanes 48, thereby providing an output from the
rotating shaft 21.
[0062] Lubrication of the vanes 48 and the pistons 47 of the
expander 4 with water is now explained.
[0063] Supply of lubricating water is carried out by utilizing the
supply pump 6 (see FIG. 1) for supplying under pressure water from
the condenser 5 to the evaporator 3, and a portion of the water
discharged from the supply pump 6 is supplied to the first water
passage W1 of the casing 11 for lubrication. Utilizing the feed
pump 6 in this way for supplying water for hydrostatic bearings of
each section of the expander 4 eliminates the need for a special
pump and enables the number of components to be reduced.
[0064] In FIG. 3 and FIG. 8, the water that has been supplied to
the first water passage W1 of the lubricating water supply member
24 flows into the small diameter portion 55a of one of the pipe
members 55 via the second water passages W2 of the seal block 25,
the third water passages W3 of the rotating shaft 21, the annular
channel 68a of the water passage forming member 68, the fourth
water passage W4 of the rotating shaft 21, and the fifth water
passages W5 formed in the pipe member 69 and the rotor segment 43,
and the water that has flowed into the small diameter portion 55a
flows into the small diameter portion 56a of the other pipe member
56 via the through hole 55b of said one of the pipe members 55, the
sixth water passage W6 formed in the pipe members 55 and 56, and
the through hole 56b formed in the other pipe member 56.
[0065] A portion of the water that has passed through the six
orifices 61b, 61c, and 61d of the orifice-forming plate 61 from the
small diameter portions 55a and 56a of the pipe members 55 and 56
via the distribution channel 62b of the lubricating water
distribution member 62 issues from the four lubricating water
outlets 43e and 43f that open on the end faces of the rotor segment
43, and another portion of the water issues from the lubricating
water outlets 43c and 43d within the arc-shaped recesses 43a and
43b formed on the side faces of the rotor segment 43.
[0066] In this way, the water issuing from the lubricating water
outlets 43e and 43f on the end faces of each of the rotor segments
43 into the vane channel 49 supports the vane 48 in a floating
state by forming a hydrostatic bearing between the vane channel 49
and the vane 48, which is slidably fitted in the vane channel 49,
thus preventing physical contact between the end face of the rotor
segment 43 and the vane 48 and thereby preventing the occurrence of
seizing and wear. Supplying the water for lubricating the sliding
surfaces of the vane 48 via the water passages provided in a radial
shape within the rotor 41 in this way not only enables the water to
be pressurized by virtue of centrifugal force but also enables the
temperature of the periphery of the rotor 41 to be stabilized, thus
lessening the effect of thermal expansion and thereby minimizing
the leakage of steam by maintaining a preset clearance.
[0067] Since water is retained in the recesses 48e, two of which
are formed on each of the opposite faces of the vane 48, these
recesses 48e function as pressure reservoirs, thereby suppressing
any decrease in pressure due to leakage of water. As a result the
vane 48, which is held between the end faces of the pair of rotor
segments 43, is in a floating state due to the water, and the
sliding resistance can thereby be reduced effectively. Furthermore,
when the vane 48 reciprocates, the radial position of the vane 48
relative to the rotor 41 changes, and since the recesses 48e are
provided not on the rotor segment 43 side but on the vane 48 side
and in the vicinity of the rollers 71, where the largest load is
imposed on the vane 48, the reciprocating vane 48 can always be
kept in a floating state, and the sliding resistance can thereby be
reduced effectively.
[0068] Water that has lubricated the surface of the vane 48 that
slides against the rotor segment 43 moves radially outward by
virtue of centrifugal force, and lubricates the sliding sections of
the arc-shaped face 14b of the rotor chamber 14 and the seal 72
provided on the arc-shaped face 48b of the vane 48. Water that has
completed the lubrication is discharged from the rotor chamber 14
via the exhaust ports 91.
[0069] In FIG. 2, by supplying water into the pressure chambers 92
at the bottom portions of the circular seal channels 76 of the
first casing half 12 and the second casing half 13 so as to urge
the ring seals 79 toward the side faces of the rotor 41, and making
the water issue from the lubricating water outlets 43c and 43d
formed within the recesses 43a and 43b of each of the rotor
segments 43 so as to form a hydrostatic bearing on the sliding
surfaces with the flat faces 14a of the rotor chamber 14, the flat
faces 41a of the rotor 41 can be sealed by the ring seals 79 that
are in a floating state within the circular seal channels 76 and,
as a result, the steam within the rotor chamber 14 can be prevented
from leaking through a gap with the rotor 41. In this process, the
ring seals 79 and the rotor 41 are isolated from each other by a
film of water supplied from the lubricating water outlets 43c and
43d and do not make physical contact with each other, and even if
the rotor 41 tilts, tilting of the ring seals 79 within the
circular seal channels 76 so as to track the tilting of the rotor
41 enables stable sealing characteristics to be maintained while
minimizing the frictional force.
[0070] The water that has lubricated the sliding section between
the ring seals 79 and the rotor 41 is supplied to the rotor chamber
14 by virtue of centrifugal force, and discharged therefrom to the
exterior of the casing 11 via the exhaust ports 91.
[0071] Furthermore, in FIG. 5, water that has been supplied from
the sixth water passage W6 within the pipe member 55 to the sliding
surfaces between the cylinder 44 and the piston 47 via the tenth
water passage W10 within the rotor segments 43 and the annular
channel 67 of the outer periphery of the cylinder 44 exhibits a
sealing function by virtue of the viscous properties of the film of
water formed on the sliding surfaces, thereby preventing
effectively the high temperature, high pressure steam supplied to
the cylinder 44 from leaking past the sliding surfaces with the
piston 47. Since the water that is supplied to the sliding surfaces
between the cylinder 44 and the piston 47 through the interior of
the expander 4, which is in a high temperature state, is heated, it
is possible to minimize any decrease in output of the expander 4
that might be caused by this water cooling the high temperature,
high pressure steam supplied to the cylinder 44.
[0072] Furthermore, the first water passage W1 and the eleventh
water passage W11 are independent from each other, and water is
supplied at a pressure that is required for each of the lubrication
sections. More specifically, the water that is supplied from the
first water passage W1 is mainly for floatingly supporting the
vanes 48 and the rotor 41 by means of a hydrostatic bearing as
described above, and it is required to have a high pressure that
can counterbalance variations in the load. In contrast, the water
that is supplied from the eleventh water passage W11 mainly
lubricates the surroundings of the fixed shaft 85, and since it is
for sealing the high temperature, high pressure steam that leaks
from the third steam passages S3 past the outer periphery of the
fixed shaft 85 so as to reduce the influence of thermal expansion
of the fixed shaft 85, the rotating shaft 21, the rotor 41, etc.,
it is only required to have a pressure that is at least higher than
the pressure of the transit chamber 19.
[0073] Since there are provided in this way two water supply lines,
that is, the first water passage W1 for supplying high pressure
water and the eleventh water passage W11 for supplying lower
pressure water, problems caused when only one water supply line for
supplying high pressure water is provided can be eliminated. That
is, the problem of water having excess pressure being supplied to
the surroundings of the fixed shaft 85, thus increasing the amount
of water flowing into the transit chamber 19, and the problem of
the fixed shaft 85, the rotating shaft 21, the rotor 41, etc. being
overcooled, thus decreasing the temperature of the steam, can be
prevented, and as a result the output of the expander 4 can be
increased while reducing the amount of water supplied.
[0074] Moreover, since water, which is the same substance as steam,
is used as a medium for sealing, there will be no problem even if
the steam is contaminated with water. If the sliding surfaces of
the cylinder 44 and the piston 47 were sealed by an oil, since it
would be impossible to prevent the oil from contaminating the water
or the steam, a special filter device for separating the oil would
be required. Furthermore, since a portion of the water for
lubricating the sliding surfaces of the vane 48 and the vane
channels 49 is separated for sealing the sliding surfaces of the
cylinder 44 and the piston 47, it is unnecessary to specially
provide an extra water passage for guiding the water to the sliding
surfaces, thus simplifying the structure.
[0075] FIG. 14A shows the shape of the annular channel 74 of the
present embodiment, and FIG. 14B shows the shape of an annular
channel 74 of a conventional example. Whereas the annular channel
74 of the conventional example is elliptical, the shape of the
annular channel 74 of the present invention is a rhombus having its
four apexes rounded. As a result, in the conventional example, the
clearance between an inner peripheral face 93 of the rotor chamber
14 and an outer peripheral face 94 of the rotor 41 becomes a
minimum at a point P1 where the phase is 0.degree. and a point P2
where the phase is 180.degree., and the clearance gradually
increases before and after the minimum. On the other hand, in the
present embodiment, the clearance between the inner peripheral face
93 of the rotor chamber 14 and the outer peripheral face 94 of the
rotor 41 is maintained at a constant minimum value over the range
of .+-.16.degree. with reference to points P1 and P2, and the
clearance gradually increases before and after this range. That is,
in the above range of .+-.16.degree. the inner peripheral face 93
of the rotor chamber 14 and the annular channel 74 form a partial
arc shape with the axis L as the center.
[0076] With regard to the rotary valve V, communication between the
notch 85a of the fixed shaft 85 and the third steam passage S3 is
blocked at the position of -16.degree. with reference to point P1
having a phase of 0.degree. and point P2 having a phase of
180.degree., thus ending the discharge of steam, and communication
between the second steam passage S2 and the third steam passage S3
is provided at the position of +16.degree. with reference to point
P1 having a phase of 0.degree. and point P2 having a phase of
180.degree., thus starting the supply of steam. Therefore, the
interior space of the cylinder 44 is hermetically sealed over the
range of .+-.16.degree. with reference to point P1 and point P2.
When the piston 47 moves in a state in which the interior space of
the cylinder 44 is hermetically sealed, there is no problem if
steam, which is compressible, is present within the cylinder 44,
but if water, which is non-compressible, is present, the phenomenon
of water hammer occurs. Although high temperature, high pressure
steam is supplied to the cylinder 44, if the high temperature, high
pressure steam supplied to the cylinder 44 is cooled and liquefies
when the expander 4 is started from cold, etc., water builds up
within the cylinder 44, thus giving rise to a possibility that the
water hammer phenomenon might occur.
[0077] However, in the present embodiment, in the region in which
the interior space of the cylinder 44 is hermetically sealed, that
is, the range of .+-.16.degree. with reference to point P1 and
point P2, since the annular channel 74 forms a partial arc with the
axis L as the center, it is possible to stop the piston 47 from
moving relative to the cylinder 44, thereby reliably preventing the
occurrence of the water hammer phenomenon.
[0078] FIG. 15A shows the intake and exhaust timing of the present
embodiment, and FIG. 15B shows the intake and exhaust timing of the
conventional example. In both of the above-mentioned cases, twelve
vanes 48 are supported on the rotor 41 at equal intervals, and the
central angle formed by a pair of adjacent vanes 48 is therefore
30.degree.. In the conventional example shown in FIG. 15B, the
phase of the vane 48 for which communication between the exhaust
ports 91 and the vane chamber 75 defined by a pair of vanes 48 is
blocked (exhaust completion phase) is set at -24.degree. with
reference to point P1 and point P2, and the phase of the vane 48
for which communication between the vane chamber 75 and the intake
ports 90 is provided (intake initiation phase) is set at +4.degree.
with reference to point P1 and point P2. Therefore, at the moment
when communication between the vane chamber 75 and the exhaust
ports 91, which are at low pressure, is blocked, steam is
introduced because the vane chamber 75 is already in communication
with the intake ports 90, which are at high pressure. In this
process, since the exhaust completion phase of -24.degree. and the
intake initiation phase of +4.degree. are asymmetric, among the
pair of vanes 48 defining the vane chamber 75, the vane 48 on the
retarded side in the rotational direction R projects by a larger
amount than the vane 48 on the advanced side in the rotational
direction R, and a higher steam pressure is applied to the vane 48
on the retarded side in the rotational direction R, thus generating
a torque in the opposite direction to the rotational direction R of
the rotor 41. As a result, there is a possibility that the rotor 41
might rotate backward when starting, or vibration might occur due
to torque variation during operation.
[0079] In the conventional example shown in FIG. 15B, since the
difference in phase between the exhaust completion phase and the
intake initiation phase is 28.degree., which is less than the angle
between the vanes of 30.degree., there is a period during which the
vane chamber 75 communicates simultaneously with the intake ports
90, which are at high pressure, and the exhaust ports 91, which are
at low pressure, and during this period a small amount of steam
blows through from the intake ports 90 to the exhaust ports 91. In
order to avoid this steam blowing through, it is necessary to
eliminate the period during which the vane chamber 75 communicates
simultaneously with the intake ports 91, which are at high
pressure, and the exhaust ports 91, which are at low pressure, and
if, for example, the intake initiation phase is increased from
+4.degree. to +6.degree., at the moment when communication between
the vane chamber 75 and the exhaust ports 91, which are at low
pressure, is blocked and the vane chamber 75 communicates with the
high pressure intake ports 90, the volume of the vane chamber 75
temporarily decreases. This is due to the front-to-back asymmetry
of the exhaust completion phase and the intake initiation phase.
When the volume of the hermetically sealed vane chamber 75
decreases in this way, if lubricating water or water formed by
liquefaction of steam is trapped in the vane chamber 75, the water
hammer phenomenon might occur, thereby resulting in vibration,
noise, degradation of durability, etc.
[0080] In contrast, in the present embodiment shown in FIG. 15A,
the exhaust completion phase and the intake initiation phase are
set at -15.degree. and +15.degree. respectively, and in a section
in which the phase is -16.degree. to +16.degree., the clearance
between the inner peripheral face 93 of the rotor chamber 14 and
the outer peripheral face 94 of the rotor 41 is set so as to be
constant. Therefore, when steam is supplied from the high pressure
intake ports 90 to the vane chamber 75, among the pair of vanes 48
defining the vane chamber 75, both the amount of projection of the
vane 48 on the retarded side in the rotational direction R and the
amount of projection of the vane 48 on the advanced side in the
rotational direction R are equal to the clearance, and it is thus
possible to prevent a torque from being generated in the opposite
direction to the rotational direction R of the rotor 41, thereby
preventing the occurrence of backward rotation of the rotor 41 and
variation in torque. Moreover, at the moment at which communication
between the vane chamber 75 and the low pressure exhaust ports 91
is blocked and the vane chamber 75 communicates with the high
pressure intake ports 90, the volume of the vane chamber 75, which
has a constant clearance, does not change, and there is therefore
no possibility of the water hammer phenomenon occurring even if
water is trapped in the vane chamber 75, thereby reliably
preventing vibration, noise, degradation of durability, etc.
[0081] In order to efficiently convert the pressure energy of steam
into mechanical energy, it is necessary to increase the expansion
ratio of the steam after it is taken in from the intake ports 90
into the vane chamber 75 up to the point where it is discharged via
the exhaust ports 91, and it is therefore desirable to advance the
intake initiation phase as much as possible. However, since the
intake initiation phase of the present embodiment is +15.degree.,
which is retarded relative to the intake initiation phase of
+4.degree. of the conventional example, the present embodiment is
disadvantageous from the viewpoint of ensuring a large expansion
ratio. The present embodiment therefore employs for the inner
peripheral face 93 of the rotor chamber 14 a shape that makes the
intake volume of steam at the beginning of the intake stroke small
(that is, the shape of the annular channel 74), thus ensuring that
the expansion ratio is the same as that of the conventional
example.
[0082] In the region from the intake initiation position, which is
set at +15.degree., to the exhaust completion position, which is
set at -15.degree., there is disposed at least the seal 72 of one
of the vanes 48, which are disposed at intervals of 30.degree..
This seal 72 prevents steam from leaking from the intake ports 90,
which are at high pressure, to the exhaust ports 91, which are at
low pressure, but in practice it is difficult to completely prevent
the leakage of the steam using only the seal 72. In the present
embodiment, since the clearance from the outer peripheral face 94
of the rotor 41 is constant in the section in which the phase of
the inner peripheral face 93 of the rotor chamber 14 is -16.degree.
to +16.degree., by making the labyrinths 43g provided on the outer
periphery of the rotor 41 face this section, a steam leakage
preventing effect is exhibited.
[0083] FIG. 16 shows a state in which a seal 72(f) on the advanced
side in the rotational direction R of the rotor 41 (hereinafter,
simply called the advanced side) has reached the intake ports 90,
and a seal 72(r) on the retarded side in the rotational direction R
of the rotor 41 (hereinafter, simply called the retarded side) has
passed the exhaust ports 91. In this case, high pressure steam of
the intake ports 90 tries to pass the seal 72(r) on the retarded
side and leak to the exhaust ports 91, but since the labyrinths 43g
present in the -16.degree. to +16.degree. section exhibit sealing
characteristics due to a labyrinth effect, it is possible to
prevent effectively the leakage of steam through the seal 72(r) on
the retarded side.
[0084] FIG. 17 shows a state in which the rotor 41 has rotated
further from the state of FIG. 16, and the seal 72(r) on the
retarded side has reached a position substantially midway between
the intake ports 90 and the exhaust ports 91, and FIG. 18 shows a
state in which the rotor 41 has rotated further from the state of
FIG. 17, and the seal 72(r) on the retarded side has reached a
position immediately prior to the intake ports 90. In all of the
above-mentioned cases, the labyrinths 43g present in the
-16.degree. to +16.degree. section exhibit sealing characteristics
due to the labyrinth effect, and it is therefore possible to
prevent effectively steam from leaking through the seal 72(r) on
the retarded side.
[0085] Since lubricating water or water that is formed by the
liquefaction of steam easily builds up in the labyrinths 43g, a
liquid sealing effect from this water also improves the sealing
characteristics for steam.
[0086] A second embodiment of the present invention is now
explained with reference to FIG. 19 to FIG. 21. The phases of vanes
48 in FIG. 19 to FIG. 21 correspond to the phases of the vanes 48
in FIG. 16 to FIG. 19 respectively.
[0087] In the first embodiment, the labyrinths 43g are provided on
the entire circumference of the rotor 41, but in the second
embodiment labyrinths 43g are provided on only about a quarter of
each of rotor segments 43 on the retarded side, and the labyrinths
43g are therefore provided at a position adjacent to the advanced
side of a seal 72 of the vane 48. The high pressure of intake ports
90 is therefore reduced in pressure by the labyrinth effect of the
labyrinths 43g adjacent to the advanced side of the seal 72, and
the difference in pressure between the two sides of the seal 72 can
be moderated, thus preventing effectively the leakage of steam. In
accordance with the present embodiment, the number of labyrinths
43g can be reduced while maintaining the steam leakage preventing
effect, thereby contributing to a reduction in the machining
cost.
[0088] Other than the embodiments described above, as an
arrangement for a power conversion device for converting the
forward movement of pistons 47 into the rotational movement of a
rotor 41, the forward movement of the pistons 47 can be directly
transmitted to rollers 71 without involving vanes 48, and can be
converted into rotational movement by engagement with annular
channels 74. Furthermore, as long as the vanes 48 are always spaced
from the inner peripheral face of a rotor chamber 14 by a
substantially constant gap as a result of cooperation between the
rollers 71 and the annular channels 74 as described above, the
pistons 47 and the rollers 71, and also the vanes 48 and the
rollers 71, can independently work together with the annular
channels 74.
[0089] When the expander 4 is used as a compressor, the rotor 41 is
rotated by the rotating shaft 21 in a direction opposite to the
arrow R in FIG. 4, outside air is drawn in by the vanes 48 from the
exhaust ports 91 into the rotor chamber 14 and compressed, and the
low pressure compressed air thus obtained is drawn in from the
intake ports 90 into the cylinders 44 via the transit chamber 19,
the through holes 81b, the fifth steam passages S5, the fourth
steam passages S4, the notches 85a of the fixed shaft 85 and the
third steam passages S3, and compressed there by the pistons 47 to
give high pressure compressed air. The high pressure compressed air
thus obtained is discharged from the cylinders 44 via the third
steam passages S3, the second steam passages S2, the first steam
passage S1, and the steam supply pipe 88. When the expander 4 is
used as a compressor, the steam passages S1 to S5 and the steam
supply pipe 88 are read instead as air passages S1 to S5 and air
supply pipe 88.
[0090] Although embodiments of the present invention are described
in detail above, the present invention can be modified in a variety
of ways without departing from the scope and spirit thereof.
[0091] For example, in the embodiments, the expander 4 is
illustrated as the rotary fluid machine, but the present invention
can also be applied to a compressor.
[0092] Furthermore, in the embodiments, steam and water are used as
the gas-phase working medium and the liquid-phase working medium,
but other appropriate working media can also be employed.
[0093] Moreover, in the embodiments, the labyrinths 43g are
provided on the rotor 41 side, but the same operational effect can
be achieved by providing labyrinths on the rotor chamber 14
side.
[0094] Furthermore, the labyrinths 43g of the embodiments are
U-shaped channels extending within a plane containing the axis L,
but they may be divided into a plurality of small cells by means of
partitions extending in the circumferential direction.
[0095] Industrial Applicability
[0096] The present invention can desirably be applied to an
expander employing steam (water) as a working medium, but can also
be applied to an expander employing any other working medium and a
compressor employing any working medium.
* * * * *