Rotary expansible chamber devices – Working member has planetary or planetating movement – Helical working member – e.g. – scroll
Reexamination Certificate
2002-11-07
2004-01-27
Vrablik, John J. (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Helical working member, e.g., scroll
C418S006000, C418S055400
Reexamination Certificate
active
06682328
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a scroll fluid machine for compressing or expanding or pressure feeding fluid, specifically to a seal configuration of a scroll fluid machine having multistage compression section in which the fluid compressed in the preceding stage compression section is cooled to be compressed in the succeeding stage compression section and a seal element is provided to prevent the leakage of the compressed fluid from the succeeding stage compression section to the preceding stage compression section.
2. Description of the Related Art
It is general in scroll fluid machines that revolving scrolls and stationary scrolls are cooled with cooling air or cooling fluid to remove the heat generated by the compression of the fluid. To attain a compression ratio larger than usual is possible by increasing the number of turns of the scroll. However, there arise problems by increasing the compression ratio than usual that not only the machine becomes large but the life of the bearings and seal elements are shortened due to the high temperature higher than usual owing to the larger compression ratio.
Therefore it becomes necessary to provide a larger cooling device to obtain a larger amount of cold heat for removing the increased heat due to increase compression ratio from the revolving scroll and stationary scroll. In a scroll fluid machine, the fluid is taken in from the peripheral part of the end plate of the revolving scroll, the compression space into which the fluid is taken in is reduced toward the center to compress the fluid, and the compressed fluid is discharged from the discharge port located in the center part. High level technique is necessary to efficiently cool the center part.
For this reason, a multistage compression type scroll machine was demanded which has two stages of compression sections, the compressed fluid discharged from the preceding stage being passed through the cooler to be introduced to the succeeding stage to be again compressed. The multistage compression type scroll machine can compress fluid to a desired high compression ratio without raising the temperature of the constituent parts of the scroll fluid machine higher than usual by restraining the temperature of the compressed fluid in the preceding stage to the temperature the constituent parts allow, cooling the compressed fluid compressed in the preceding stage compression section, and then again compressing the compressed and cooled fluid if the succeeding stage compression section.
A multistage compression type scroll machine which has two stages of compression sections and in which the compressed fluid from the preceding stage is cooled by passing through a cooler and then introduced to the succeeding stage to be again compressed is disclosed in Japanese Unexamined Patent Publication 54-59608.
The conventional art includes, however, the problem as described below. This will be explained with reference to
FIGS. 10
to
12
. The discharge port
2
e
in the vicinity of the final compression chamber of the preceding stage compression section and the suction port
2
f
, which communicate with the space into which the fluid is taken in, of the succeeding stage compression section are connected with a piping by the medium of a cooler not shown in the drawing, the connection constituting an intermediate passage.
Now, after the compression space S
3
of the preceding stage compression section communicates with the discharge port
2
e
of the preceding stage compression section, the compression space S
6
and T
6
of the succeeding stage compression section become communicated with the compression space S
5
of the preceding stage compression section, as shown in FIG.
10
. The fluid taken into the compression space S
6
is compressed by the rotation of the revolving scroll lap
10
b
to the compression space S
8
, and the fluid taken into the compression space T
6
is compressed to the compression space T
8
. Therefore, the pressure in the space S
8
is higher than that in the space S
6
, and the pressure in the space T
8
is higher than that in the space T
6
.
As can be seen in FIG.
11
(
a
), FIG.
11
(
b
), and
FIG. 12
, which show respectively A—A section, B—B section, and C—C section in
FIG. 10
, a tip seal
53
is received in the groove
41
formed in the tip of the revolving scroll lap
10
b
and in the groove
40
formed in the tip of the stationary scroll lap
9
c
respectively. As the tip seal
53
is shaped narrower in width than that of the groove
40
and
41
, the tip seals
53
,
53
receive the pressure of the compressed fluid of each compression space to be pushed against the mirror face each mating scroll and at the same time to be pushed against the wall each groove toward lower pressure side.
Accordingly, the passage
30
and
31
communicating with the compression space T
6
are formed as shown in FIG.
11
(
a
), and the leakage to the lower pressure space T
6
is possible.
The passage
32
and
51
communicating with the compression space S
8
are formed as shown in FIG.
11
(
b
), and the leakage to the lower pressure space S
6
is possible.
The tip seal is pushed against the groove wall toward lower pressure side. However, the side face of the tip seal and the groove face can not be brought to absolute contact with each other because of the imperfect flatness of the faces. Accordingly, the leakage of high pressure fluid in the direction of arrow
76
to the gap
80
between the tip seal
14
and
53
is possible as shown in FIG.
12
(
a
) which shows C—C section in FIG.
10
.
There is a gap between the bottom of the groove formed in the tip of the revolving scroll lap and the tip seal
53
, so the leakage of the fluid is possible from higher pressure side to lower pressure side. This means that, as a gap exists between the end face
41
a
of the groove
41
and the end face
53
a
of the tip seal
53
at the end part
10
d
of the revolving scroll lap
53
, the leakage of the compressed fluid in the direction of arrow
78
is possible, and also the leakage as shown by arrow
77
is possible from the passage
51
.
Therefore, as shown in FIG.
10
and FIG.
12
(
a
), the high pressure fluid leaks from the succeeding stage compression section to the preceding stage compression section through the gap
80
shown by arrow
29
and
76
to be taken into the preceding stage compression section to be compressed again, which causes problems of high temperature and excessive power requirement for compression.
SUMMARY OF THE INVENTION
The present invention was made to solve the problem mentioned above, the object is to provide the seal construction of a multi-stage compression type scroll fluid machine for preventing the leakage of high pressure compressed fluid to the preceding stage compression section from the succeeding stage compression section.
To solve the problem mentioned above, the present invention offers a scroll fluid machine with multistage compression section in which the fluid compressed in the preceding stage compression section is further compressed in the succeeding stage compression section characterized in that:
a lap groove is formed spiraling from the vicinity of the discharge port of the compressed fluid of the final stage compression space to the fluid take-in side of the initial stage compression space, in the tip of the lap being formed a tip seal grove to receive a seal element, and a rand is formed between the discharge port at the compression end part of said preceding stage compression section and the suction port of the succeeding stage compression section; and
an intermediate seal element is received in the intermediate groove formed on the surface of said rand which faces the end plate of the mating scroll for preventing the leakage of the compressed fluid from said succeeding stage compression section to said discharge port opening side of said preceding stage compression section.
In the present invention, the scroll lap on the tip of which is located a tip seal which contacts and slid
Kimura Hideyuki
Unami Atsushi
Anest Iwata Corporation
Crowell & Moring LLP
Vrablik John J.
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