Pumps – Motor driven – Axial thrust balancing means for rotary pump and motor
Reexamination Certificate
2002-05-23
2004-05-04
Yu, Justine R. (Department: 3746)
Pumps
Motor driven
Axial thrust balancing means for rotary pump and motor
C417S244000, C417S357000, C417S366000, C417S371000, C417S372000
Reexamination Certificate
active
06729858
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a turbo compressor, and more particularly, to a turbo compressor that is capable of effectively cooling a bearing which supports a rotational shaft.
2. Description of the Background Art
FIG. 1
is a sectional view of a turbo compressor in accordance with a conventional art.
As shown in
FIG. 1
, the conventional turbo compressor includes a casing
106
having a suction hole
102
for sucking a fluid from an outside and a discharge hole
104
for discharging the sucked fluid, and having a certain space; a driving unit
108
installed inside the casing
106
and generating a rotational force; a first compressing part
112
connected to the driving unit
108
by a rotational shaft
110
and first compressing fluid; and a second compressing part
114
for secondly compressing the fluid compressed by the first compressing part
112
.
In the casing
106
, a fluid chamber
120
for sucking a fluid through the suction hole is formed, a first support member
116
for rotatably supporting one end portion of the rotational shaft
110
is fixed at one side of the casing
106
, and a second support member
118
for rotatably supporting the other end portion of the rotational shaft
110
is fixed at the other side of the casing
106
.
The driving unit
108
includes a stator
122
fixed at an outer circumferential face of the casing
106
and receiving a power from an external source, and a rotor
124
fixed at a circumferential face of the rotational shaft
110
and being rotated by an interaction with the stator
122
.
The first compressing part
112
includes a first impeller
126
connected to one end portion of the rotational shaft
110
and compressing the fluid by being rotated along with the rotational shaft
110
; and a first cover member
132
in which the first impleller
126
is rotatably inserted, a first compression chamber
128
is connected to the discharge hole
104
of the main body, into which the fluid of the fluid chamber
120
is introduced and first compressed, and a transfer passage
130
is formed to discharge the compressed fluid.
The second compressing part
114
includes a second impeller
134
connected to the other end portion of the rotational shaft
110
and compressing the fluid by being rotated along with the rotational shaft
110
; and a second cover member
140
in which the second impeller
134
is rotatably inserted, a second compression chamber
136
is formed connected to the transfer passage
130
into which the first compressed fluid is introduced and secondly compressed, and a discharge hole
138
is formed to externally discharge the compressed coolant.
A radial bearing
142
is inserted between the first support member
116
and the outer circumferential face of the rotational shaft
110
and between the second support member
118
and the outer circumferential face of the rotational shaft
110
, to support a load working in a radial direction of the rotational shaft
110
.
A bearing bush
144
is connected in a vertical direction to the rotational shaft at one side thereof. The bearing bush
144
is supplied by a thrust bearing
146
which supports a load working in an axial direction of the rotational shaft
110
.
The thrust bearing
146
is installed between the first cover member
132
and the first support member
116
, and a bearing chamber
148
is formed where the bearing bush
144
is rotatably positioned.
A sealing member
150
is inserted between the outer circumferential face of both end portions of the rotational shaft
110
and the first cover member
132
, to prevent leakage of the fluid compressed in the first and the second compression chambers
128
and
136
.
The operation of the turbo compressor in accordance with the conventional art constructed as described above will now be explained.
When the driving unit
108
is driven, the rotational shaft
110
is rotated. Then the first impeller
126
and the second impeller
134
connected to the rotational shaft
110
are rotated to perform a compressing operation of the fluid.
That is, the fluid is introduced into the fluid chamber
120
through the suction hole
102
, and the fluid introduced into the fluid chamber
120
is introduced into the first compression chamber
128
through the discharge hole
104
, first compressed according to the rotation of the first impeller
126
and then supplied to the transfer passage
130
.
The fluid supplied to the transfer passage
130
is introduced into the second compression chamber
136
, secondly compressed by the rotation of the second impeller
134
and then externally discharged through the discharge hole
138
.
At this time, when the rotational shaft
110
is being rotation, a load working in a radial direction of the rotational shaft
110
is supported by the radial bearing
142
.
Since the pressure in the first compression chamber
128
which compresses the fluid first is smaller than that of the second compression chamber
136
, an axial-directional load works on the rotational shaft
110
due to the pressure difference between the first compression chamber
128
and the second compression chamber
136
. Such axial-directional load is supported by the thrust bearing
146
.
In this respect, since the rotational shaft
110
is rotated at a high speed, a temperature of the bearing chamber
148
with the thrust bearing
146
is inserted is increased and the thrust bearing
146
is degraded. Thus, in view of the performance of the whole system and in order to lengthen the life of the bearing, it is requisite to cool the thrust bearing
146
and maintain its temperature to below a certain level.
The conventional bearing cooling method is that, in designing a structure of the sealing member
150
inserted between the first cover member
132
and the rotational shaft
110
, a certain leakage of fluid is allowed to occur, so that when the fluid which is first compressed after being introduced into the first compression chamber
128
is introduced into the bearing chamber
148
through the sealing member
150
, thereby performing a cooling operation of the thrust bearing
146
.
However, the conventional turbo compressor has a problem that the leakage amount of fluid supplied from the first compression chamber to the bearing chamber differs depending on a structure designing of the sealing member.
That is, if a small amount of fluid is leaked to the bearing chamber, the cooling operation of the thrust bearing is not smoothly performed, and thus, the temperature is increased according to the friction of the bearing. Then, a coating layer of the bearing is damaged, resulting in that the performance of the whole system is degraded, the durability of the bearing is shortened, and a reliability is degraded.
On the other hand, if a large amount of fluid is leaked to the bearing chamber, when the fluid is compressed, a large amount of fluid is leaked, resulting in that a compression efficiency of the compressor is degraded.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a turbo compressor that is capable of smoothly performing a cooling operation of a bearing without degrading a compression performance of a compressor in such a manner that when a temperature of a bearing chamber with a thrust bearing inserted therein increases, a fluid is supplied to perform a cooing operation, and when the temperature of the bearing chamber reaches a suitable level, the fluid supply to the bearing chamber is cut off.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a turbo compressor including: a casing having a fluid chamber for receiving a fluid from an external source; a driving unit disposed in the casing and generating a rotational force; a first compressing part installed at one side of a rotational shaft rotated according to the driving of the driving unit and first compressing the fluid; a second compressing part installed at
Choi Moon-Chang
Ji Yoo-Chol
Kim Hoi-Sun
Kim Young-Kwan
Suh Kwang-Ha
LG Electronics Inc.
Solak Timothy P.
Yu Justine R.
LandOfFree
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