Refrigeration – Automatic control – Selective heating or cooling
Reexamination Certificate
1999-09-13
2001-03-20
McDermott, Corrine (Department: 3744)
Refrigeration
Automatic control
Selective heating or cooling
C062S324600, C062S505000
Reexamination Certificate
active
06202428
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an air conditioner and, more particularly, to a compressor used for reversible refrigerant circuit (reversible refrigeration cycle) capable of performing the switching between cooling operation and heating operation.
BACKGROUND ART
An air conditioner has a refrigerant circuit in which an outdoor-side heat exchanger, an expansion valve, and an indoor-side heat exchanger are connected with a compressor in a loop form by refrigerant pipes via a four-way switching valve. In the air conditioner, by switching the flow direction of a refrigerant by means of the four-way switching valve, either of cooling operation and heating operation is set.
A compressor used for this refrigerant circuit is broadly classified into an internal high pressure type and an internal low pressure type.
FIG. 20
shows a refrigerant circuit using an internal high pressure type compressor
1
A, and
FIG. 21
shows a refrigerant circuit using an internal low pressure type compressor
1
B.
The basic configurations of the compressors
1
A and
1
B are the same. The compressor of either type has a cylindrical enclosed vessel
2
, and the enclosed vessel
2
contains a refrigerant compressing section
3
and an electric motor
4
. Although not shown in detail, the refrigerant compressing section
3
, being of a scroll type, has a compression chamber formed by engaging a fixed scroll having a spiral wrap on an end plate with an orbiting scroll driven by the electric motor
4
.
The interior of the enclosed vessel
2
is divided into two chambers by the end plate on the side of the fixed scroll in the refrigerant compressing section
3
. One of these two chambers is a refrigerant discharge chamber
5
provided on the side of a discharge port
3
a
of the refrigerant compressing section
3
. The other is an electric motor chamber
6
in which the electric motor
4
is contained. Also, the electric motor chamber
6
is provided with a bearer plate
7
which pivotally supports a driving shaft
4
a
of the electric motor
4
. A subsidiary electric motor chamber
6
a
is formed on the side opposite to the refrigerant discharge chamber
5
of the electric motor chamber
6
by the bearer plate
7
. The bearer plate
7
is formed with an arbitrary number of refrigerant flowing holes
7
a.
Either of the compressors
1
A and
1
B is connected, via a four-way switching valve
8
, with a heat exchanging circuit in which an outdoor-side heat exchanger
9
, an expansion valve (or a capillary tube)
10
, and an indoor-side heat exchanger
11
are connected in a loop form by refrigerant pipes.
The configurations of the internal high pressure type compressor
1
A and the internal low pressure type compressor
1
B differ in the following respects: That is, in the internal high pressure type compressor
1
A shown in
FIG. 20
, the refrigerant discharge chamber
5
communicates with the electric motor chamber
6
via a communicating path
12
, and a suction pipe
13
for low-pressure refrigerant drawn from the four-way switching valve
8
is directly connected to a suction port
3
b
of the refrigerant compressing section
3
.
Contrarily, in the internal low pressure type compressor
1
B shown in
FIG. 21
, the refrigerant discharge chamber
5
and the electric motor chamber
6
are independent of each other. The suction port
3
b
of the refrigerant compressing section
3
is opened on the side of the electric motor chamber
6
, and the suction pipe
13
drawn from the four-way switching valve
8
is connected to the electric motor chamber
6
.
The following is a description of the operations of the compressors
1
A and
1
B.
FIG. 20
shows a state at the time of cooling operation using the internal high pressure type compressor
1
A. A low-pressure refrigerant from the indoor-side heat exchanger
11
is sucked into the refrigerant compressing section
3
through the suction pipe
13
. After being compressed, the refrigerant is discharged into the refrigerant discharge chamber
5
as a high-temperature high-pressure refrigerant gas. This high-temperature high-pressure refrigerant gas is supplied to the outdoor-side heat exchanger
9
through a discharge pipe
14
for high-pressure refrigerant and the four-way switching valve
8
. Also, some of the high-temperature high-pressure refrigerant gas flows into the electric motor chamber
6
through the communication path
12
. Thereby, the compressor
1
A is classified as the internal high pressure type.
For the internal high pressure type, the discharge pipe
14
for high-pressure refrigerant is connected to the side of the subsidiary electric motor chamber
6
a,
not to the refrigerant discharge chamber
5
, as indicated by the chain line in
FIG. 20
so that a high-pressure refrigerant is introduced from the subsidiary electric motor chamber
6
a
to the four-way switching valve
8
.
At the time of heating operation, the four-way switching valve
8
is turned 90 degrees from the state shown in
FIG. 20
, so that the discharge pipe
14
for high-pressure refrigerant is connected to the indoor-side heat exchanger
11
, and the suction pipe
13
for low-pressure refrigerant is connected to the outdoor-side heat exchanger
9
.
FIG. 21
shows a state at the time of heating operation using the internal low pressure type compressor
1
B. The low-pressure refrigerant from the outdoor-side heat exchanger
9
flows into the electric motor chamber
6
through the suction pipe
13
, so that the interior thereof becomes low in pressure. The low-pressure refrigerant is sucked into the refrigerant compressing section
3
through the suction port
3
b.
After being compressed, the refrigerant is discharged into the refrigerant discharge chamber
5
as a high-temperature high-pressure refrigerant gas, and is supplied to the indoor-side heat exchanger
11
through the discharge pipe
14
and the four-way switching valve
8
. At the time of cooling operation; the four-way switching valve
8
is turned 90 degrees from the state shown in
FIG. 21
, so that the discharge pipe
14
for high-pressure refrigerant is connected to the outdoor-side heat exchanger
9
, and the suction pipe
13
for low-pressure refrigerant is connected to the indoor-side heat exchanger
11
.
In either of the internal high pressure type and the internal low pressure type, an object of introducing the refrigerant into the electric motor chamber is to prevent overheat of the electric motor, and these two types have advantages and disadvantages as described below.
In case of the internal high pressure type, since a lubricating oil can be separated from the refrigerant gas in the electric motor chamber, the lubricating oil is positively supplied into the compressor, by which good sealing can be provided between rubbing portions of the fixed scroll and the orbiting scroll in the refrigerant compressing section. Also, by making the interior of the electric motor chamber high in pressure, a thrust force applied to the orbiting scroll can be controlled easily, and the load on the electric motor can be decreased. Accordingly, the power consumption can be lowered.
Also, in case of the internal high pressure type, since the temperature of the enclosed vessel is higher than the ambient temperature at the time of cooling operation, the heat dissipation amount is increased, so that the cooling capacity can be increased. However, the internal high pressure type is disadvantageous in terms of heating capacity because the amount of heat dissipating from the enclosed vessel is large.
On the other hand, in case of the internal low pressure type, since the temperature of the enclosed vessel is approximately equal to the ambient temperature at the time of heating operation, the amount of heat dissipating from the enclosed vessel is small, so that the heating capacity is high. In particular, comparing with the internal high pressure type in which the high-pressure refrigerant is discharged from the subsidiary electric motor chamber through the electric motor chamber, the internal low pressure type has a
Araki Makoto
Fujino Masaki
Furukawa Motonobu
Inagaki Takefumi
Katayama Masashi
Fujitsu General Limited
Kanesaka & Takeuchi
McDermott Corrine
Norman Marc
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