Pumps – With condition responsive pumped fluid control – Pressure responsive relief or bypass valve
Reexamination Certificate
2002-01-30
2004-01-06
Yu, Justine R. (Department: 3746)
Pumps
With condition responsive pumped fluid control
Pressure responsive relief or bypass valve
C417S311000, C417S309000, C417S410400, C417S410300
Reexamination Certificate
active
06672845
ABSTRACT:
This application is the national phase under 35U.S.C. §371 of PCT International Application No. PCT/KR00/00133 which has an International filing date of Feb. 19, 2000, which designated the United States of America and was published in English.
TECHNICAL FIELD
The present invention relates to an apparatus for preventing vacuum compression of a scroll compressor, and in particular, to an apparatus for preventing vacuum compression of a scroll compressor by which even if a compressor is continuously operated in a state that coolant does not flow into an inlet of a suction tube as the suction tube is clogged the coolant is partially leaked to a low pressure chamber, so that the inside of the compressor is not reduced to an ultra-vacuum state.
BACKGROUND ART
Generally, compressors in use for air conditions or refrigeratorsserve to convert mechanical energy to compression energy of a compressible fluid. Compressors mainly include a reciprocating type compressor, a scroll type compressor, a centrifugal type compressor (normally called a turbo type compressor), and a vane type compressor (normally called rotary type compressor).
Among them, the scroll compressor sucks and compresses gas by using a rotor to discharge it, which is like the centrifugal compressor or the vane compressor. In contrast, the reciprocating compressor uses a linear movement of a piston for the same purpose.
The scroll compressor includes a low pressure scroll compressor or a high pressure scroll compressor depending on whether a suction gas is filled inside a closed container or a discharge gas is filled therein.
FIG. 1
shows a general low pressure scroll compressor in use for the air conditioners or the refrigerators.
As shown in the drawing, the upper and the lower frames
4
and
4
′ are fixedly installed at the upper and lower portion of the inside a closed container
3
. A suction tube
1
for sucking a coolant gas and a discharge tube
2
for discharging the high pressure coolant gas are respectively installed at one side of the closed container
3
.
A drive motor
17
consisting of a stator
20
and a rotor
18
is fixedly installed between the upper frame
4
and the lower frame
4
′.
A fixing (fixed) scroll
5
is combined by a bolt
5
′ at the upper side of the upper frame
4
, and an orbiting scroll
7
is rotatably combined with the fixing scroll
5
at the lower side thereof, having a plurality of compressive chambers for compressing a coolant sucked from the suction tube
1
.
A wrap W
1
is formed in an involute shape at the inner surface of the fixing scroll
5
, and an inlet
5
a
is formed at the outermost side of the wrap W
1
, communicating with the suction tube
1
. An output
5
b
is formed at the upper side of the central portion of the closed container, communicating with the discharge tube
2
.
A wrap W
2
is engaged to be revolved on the inner surface of the orbiting scroll
6
in the fixing scroll
5
.
At the lower side of the orbiting scroll
6
, a drive shaft
13
is combined at the central portion of the rotor
18
, penetrating the upper frame
4
. The drive shaft
13
is provided with an oil passage
13
a
formed to penetrate the central portion in the length direction and an eccentric portion
3
b
formed at the upper portion thereof.
An oil feeder
16
is installed at the lower portion of the drive shaft
13
to pump oil
15
filled at the lower portion of inside the closed container
3
.
A slide bush
19
is insertedly formed at the eccentric portion
13
b
of the drive shaft
13
, which is varied in the radial direction and receives a rotational force of the drive shaft
13
in the tangential direction. An Oldham's ring
21
a rotation-preventing unit, is combined at the lower portion of the orbiting scroll
6
to prevent the orbiting scroll
6
from rotating.
A high pressure and low pressure separating plate
8
is fixedly installed at the upper side of the fixing scroll
5
by a plurality of bolts
22
. A gas discharge hole
8
a
is formed at the central portion of the upper side of the fixing scroll
5
. The inside of the closed container
3
is divided into a high pressure chamber
10
and a low pressure chamber
14
by the high and low pressure separating plate
8
. At one side of the high and low pressure separating plate
8
, a back pressure valve
12
is combined to partially discharge the gas of the high pressure chamber
10
.
A discharge chamber
23
is formed at the upper portion of the high and low pressure separating plate
8
, communicating with the gas discharge hole
8
a
and the discharge tube
2
. At the side of the discharge hole
5
b
, a bypass hole
25
is formed to be connected with an intermediate pressure
24
formed between the fixing scroll
5
and the orbiting scroll
6
. A bypass valve
26
is installed at the upper side of an inlet of the upper portion of the bypass hole
The operation of the scroll compressor of the background art constructed as described above will now be explained.
When the rotor
18
is rotated by an applied current, the drive shaft
13
is rotated as being eccentric as long as the eccentric distance of the eccentric portion
13
b
according to the rotation of the rotor
18
, so that the orbiting scroll
6
is circularly moved.
Prevented from rotating by the Oldham's ring
21
, that is, the rotating-prevention unit, the orbiting scroll
6
makes turning movement centering around the drive shaft
13
, drawing a turning circle at a distance apart as long as the turning radius. At this time, as the orbiting scroll
6
makes turning movement at the distance apart as long as the turning radius, a plurality of compressive chambers
7
are formed between the fixing scroll
5
and the two wraps W
1
and W
2
.
Accordingly, a coolant gas filled in the compressive chambers
7
by being sucked through the inlet
5
a
placed at one side of the fixing scroll
5
is moved toward the center of the scrolls
5
and
6
by the continuous turning movement of the scrolls
5
and
6
. While being moved, its volume is reduced to be compressed, discharged through the outlet
5
b
of the fixing scroll
5
and passed through the high and low pressure separating plate
8
to flow into the high pressure chamber
10
. And this coolant gas flown into the high pressure chamber
14
is introduced to a condenser (not shown) through the discharge tube
2
.
At this time in case that the pressure of the coolant being discharged to the high pressure chamber
10
is too high, the back pressure valve
12
is forced to open so as to discharge a portion of the coolant to the low pressure chamber
14
, so that an abnormal over-compression can be prevented from occurring.
In addition, when the drive shaft
13
is rotated, the oil
15
is pumped by the oil feeder installed at the lower end portion of the drive shaft
13
and supplied upwardly through the oil passage
13
a
, so that a friction resistance of a thrust face
4
a
of the upper frame
4
that contacts the orbiting scroll
6
is reduced.
However, the scroll compressor of the background art has the following problem. That is, in the abnormal pressure condition due to the over-compression, the gas can be moved by the back pressure valve. But, in case that a pipe line through which the coolant is circulated is partially clogged and thus the coolant is prevented from sucking to the sucking tube, though the compression is continuously made in the compressive chamber, the pressure of the high pressure chamber does not go beyond a pre-set pressure at which the back pressure valve is operated. Consequently, the inside of the compressor becomes a vacuum state, and if this vacuum state is maintained for a certain time, the inside of the compressor becomes ultra-vacuum state, causing a short in a charging portion of the drive motor due to degradation of electric insulation, resulting in a high possibility that the drive motor is damaged and an electric shock occurs due to a leakage current.
In addition, since oil is not sufficiently supplied to the thrust face of the upper frame contacting the
Ahn Byung Ha
Jin Hong Gyun
Kim Phill Whan
Lee Sung Jun
Lee Young Bae
Rodriguez William H.
Yu Justine R.
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