Pumps – Condition responsive control of pump drive motor – Responsive to pump or pump fluid temperature
Reexamination Certificate
2000-01-18
2002-06-04
Freay, Charles G. (Department: 3746)
Pumps
Condition responsive control of pump drive motor
Responsive to pump or pump fluid temperature
Reexamination Certificate
active
06398507
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an overheat protection device for a scroll compressor, and in particular to an improved overheat protection device for a scroll compressor which can prevent a sealing member from being damaged due to the overheat, by detecting a gas temperature in the compressor and directly stopping driving of the compressor, without using a special controller, when the gas temperature exceeds an adequate temperature.
2. Description of the Background Art
In general, compressors are divided into reciprocating compressors, scroll compressors, centrifugal compressors (generally, ‘turbo-compressors’) and sliding vane compressors (generally, ‘rotary compressors’).
Here, the scroll compressor inhales, compresses and discharges a gas by using a rotary body, similarly to the centrifugal compressor or the sliding vane compressor.
The scroll compressors are divided into low pressure scroll compressors and high pressure scroll compressors according to whether a suction gas or a discharge gas is filled in a casing.
FIG. 1
is a half cross-sectional diagram illustrating a vertical scroll compressor of the conventional low pressure scroll compressors.
As depicted in
FIG. 1
, in the conventional vertical scroll compressor, an upper frame
2
and a lower frame (not shown) are respectively fixed to the upper and lower sides of a vertical casing
1
in which oil is filled at a predetermined height; and a driving motor
4
consisting of a stator
4
A and a rotor
4
B is firmly fixed between the upper frame
2
and the lower frame (not shown).
A driving shaft
5
is rotatably inserted into the center of the rotor
4
B of the driving motor
4
, passing through the upper frame
2
.
In addition, a wrap
6
a
is formed in an involute curve at an upper surface of a main frame
2
, and an orbiting scroll
6
eccentrically connected to the driving shaft
5
is rotatably positioned. A fixed scroll
7
having a wrap
7
a
formed in the involute curve in order to compose a plurality of compression chambers by being engaged with the wrap
6
a
of the orbiting scroll
6
is fixedly disposed at the upper frame
2
.
Above the fixed scroll
7
, a discharge cover
8
dividing the inside of the casing
1
into a high pressure region and a low pressure region is fixed to the inner circumferential surface of the casing
1
. A valve assembly
9
consisting of a valve housing
9
A and a valve
9
B are provided on a gas discharge hole
8
a
of the discharge cover
8
in order to prevent a reverse-flow of the gas.
Also, an overload protector (OLP)
10
for detecting an inside temperature of the casing
1
, namely a temperature of the gas inhaled into the casing
1
, and for stopping the compressor by intercepting power applied to the driving motor
4
in the case that the gas temperature exceeds an adequate temperature is provided above the stator
4
A of the driving motor
4
, in a connection state as shown in FIG.
2
.
Reference numerals
5
a
and
7
b
denote an oil path and a discharge port, respectively. Reference marks SP and DP denote a suction pipe and a discharge pipe, respectively.
The operation of the conventional scroll compressor will now be explained.
When the power is applied, the rotor
4
B rotates with the driving shaft
5
by the power at an inner portion of the stator
4
, thereby eccentrically rotating the orbiting scroll
6
correspondingly to an eccentric distance. At the same time, the orbiting scroll
6
performs an orbiting movement correspondingly to an orbiting radius, centering around the shaft, thereby forming the plurality of compression chambers between the fixed scroll
7
and the wraps
6
a
,
7
a.
The plurality of compression chambers move to the center according to the constant orbiting movement of the orbiting scroll
6
, a volume thereof being reduced. Accordingly, an inhaled refrigerant gas is more compressed, and externally outputted through the discharge port
7
b
of the fixed scroll
7
.
At this time, the low pressure refrigerant gas is inhaled into the low pressure region of the casing
1
through the suction pipe SP, and inhaled into the compression chamber by the orbiting movement of the orbiting scroll
6
. The overload protector
10
is provided at the low pressure region of the casing
1
. Therefore, the overload protector
10
detects a temperature of the refrigerant gas filled in the low pressure region, and stops the compressor by intercepting the power applied to the driving motor
4
, when the temperature exceeds the optical temperature.
However, in the conventional scroll compressor, the discharge gas discharged through the discharge port
7
B is mixed with oil. When the temperature of the discharge gas abnormally rises, the oil is combusted (carbonized), or the gas in the compression chamber is overheated, thereby dissolving a tip seal inserted into the end portions of the wraps
6
a
,
7
a
. As a result, reliability of the compressor is reduced, and a life span of an air conditioner including the compressor is decreased.
In order to overcome such disadvantages, there was suggested a scroll compressor including a discharge gas temperature detection device as shown in FIG.
3
.
According to the aforementioned scroll compressor, a thermostat
20
for detecting the temperature of the discharge gas is connected to the controller connected to the overload protector
10
at the high pressure region of the casing
1
, and stops the compressor when the temperature of the discharge gas exceeds the adequate temperature.
However, the conventional scroll compressor having the thermostat needs a special controller, and thus cannot be used for a mechanical system, such as a window type air conditioner which does not have the controller.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an overheat protection device for a scroll compressor which can detect a gas temperature in a casing without employing a special controller, and directly stop driving of the compressor when the temperature exceeds an adequate temperature.
In order to achieve the above-described object of the present invention, in a scroll compressor having in a casing an orbiting scroll and a fixed scroll for inhaling, compressing and discharging a gas, and a driving motor for driving the orbiting scroll, there is provided an overheat protection device for the scroll compressor stopping the driving motor when a detected temperature exceeds an adequate temperature, a temperature detection device for detecting a temperature of the gas of a low pressure region where the gas is inhaled and a high pressure region where the gas is discharged through a discharge port of the fixed scroll being connected between a power terminal and the driving motor in an electrical serial state.
REFERENCES:
patent: 5118260 (1992-06-01), Fraser, Jr.
patent: 5200872 (1993-04-01), D'Entremont et al.
patent: 5452989 (1995-09-01), Rood et al.
patent: 6152700 (2000-11-01), Ginies
patent: 6171064 (2001-01-01), Hugenroth et al.
Fleshner & Kim LLP
Freay Charles G.
LG Electronics Inc.
Rodriguez William
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