Refrigeration – Automatic control – Refrigeration producer
Reexamination Certificate
2000-01-11
2001-07-24
Tanner, Harry B. (Department: 3744)
Refrigeration
Automatic control
Refrigeration producer
C062S228500, C062S159000, C417S222200
Reexamination Certificate
active
06263687
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to air conditioning systems that utilize refrigerants and a compressor, and particularly to air conditioning systems capable of alleviating excessive increases in refrigerant discharge pressure within a heating circuit.
2. Description of the Related Art
A known air conditioning system is disclosed in Japanese Unexamined Patent Publication No. 7-19630 and includes a compressor
1
, a cooling circuit
51
, a heating circuit
52
and a controller
83
, as shown in FIG.
1
. The cooling circuit
51
includes a condenser
55
, a first expansion valve
57
and a heat exchanger
59
provided on a passage connecting a discharge port D to a suction port S of the compressor
1
. High temperature and high pressure refrigerant discharged from the discharge port D of the compressor
1
is drawn through the above respective devices and back to the compressor
1
.
The heating circuit
52
includes a bypass passage
52
a
that extends from the discharge port D of the compressor
1
to the heat exchanger
59
, a second expansion valve
63
provided within the bypass passage
52
a
and the heat exchanger
59
. The high-temperature and high-pressure refrigerant discharged from the compressor
1
is not directed to the condenser
55
, but rather is drawn by the compressor
1
through the second expansion valve
63
and the heat exchanger
59
. Such a heating circuit
52
is generally known as a hot gas bypass heater.
The operation of the cooling circuit
51
and the heating circuit
52
is changeably selected by opening and closing selector valves
53
a
and
53
b,
which opening and closing operations are performed by the controller
83
.
Because the refrigerant discharge pressure is higher when the heating circuit
52
is used than when the cooling circuit
51
is used, the air conditioning system must operate in a high pressure state when the heating circuit
52
is utilized. An abnormally high-pressure state may be created if the output discharge capacity of the compressor
1
temporarily increases during the operation of the heating circuit
52
. A refrigerant releasing passage
91
having a pressure relief valve
93
is provided in order to release excess pressure from heating circuit
52
, if an abnormally high pressure state is reached. The refrigerant releasing passage
91
is connected to the heating circuit
52
and the cooling circuit
51
and the pressure relief valve
93
can be opened to release the refrigerant from the heating circuit
52
into the cooling circuit
51
when the refrigerant discharge pressure abnormally increases during the operation of the heating circuit
52
. Because the cooling circuit
51
and the heating circuit
52
are alternatively selected by the selector valves
53
a
and
53
b,
the refrigerant is released toward the cooling circuit
51
which is not used when the discharge pressure is increased abnormally during operation of the heating circuit
52
, thereby preventing the discharge pressure at the heating circuit
52
from increasing abnormally.
Because the refrigerant is released from the operating heating circuit
52
to the cooling circuit
51
which is not used, the abnormally high-pressure state of the discharge pressure during operation of the heating circuit
52
can be alleviated. However, because the refrigerant in the heating circuit
52
is released into the cooling circuit
51
whenever the discharge pressure increases, the amount of the refrigerant in the heating circuit
52
is reduced and heating performance may be reduced. Moreover, because the high-pressure refrigerant is wastefully released from the heating circuit
52
by working the compressor
1
, energy efficiency is reduced.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide an air conditioning system that can alleviate abnormally high discharge pressure without releasing the high-pressure refrigerant outside the heating circuit and without reducing the energy efficiency.
Preferably, an air conditioning system may include a compressor having a driving unit within the compressor driving chamber, a cooling circuit, a heating circuit and first and second capacity controllers. The air conditioning system may release high-pressure refrigerant from the compressor discharge port into the compressor driving chamber through a capacity control passage by utilizing the capacity controllers. By increasing the pressure within the driving chamber, the driving unit may decrease the compressor output discharge capacity. As the result, the compressor discharge pressure will be decreased and the compressor suction pressure will be increased by the reduction in the compressor output discharge capacity.
The first and the second capacity controllers are provided in series onto the capacity control passage that connects the discharge port with the driving chamber. The first capacity controller may open the capacity control passage when compressor suction pressure results predetermined low-pressure state during operation of the cooling circuit. And the second capacity controller may open the capacity control passage during operation of the cooling circuit. This is, when the compressor suction pressure results the predetermined low-pressure state during operation of the cooling circuit, high-pressure refrigerant is released from the discharge port into the driving chamber through the first and the second capacity controller. Thus, the pressure within the driving chamber increases and the driving unit decreases the compressor output discharge capacity, thereby increasing the suction pressure and preventing the heat exchanger in the cooling circuit from being frosted. The first capacity controller may open the capacity control passage during operation of the heating circuit. And the second capacity controller may open the capacity control passage when compressor discharge pressure results predetermined high-pressure state during operation of the heating circuit. This is, when the compressor discharge pressure results an abnormally high-pressure state during operation of the heating circuit, high-pressure refrigerant is released from the discharge port into the driving chamber through the first and the second capacity controller. As the result, the pressure within the driving chamber increases and the driving unit decreases the compressor output discharge capacity, thereby alleviating the discharge pressure and preventing the heating circuit from being damaged by the abnormally high discharge pressure.
Other objects, features and advantages of the present invention will be readily understood after reading the following detailed description together with the accompanying drawings and the claims.
REFERENCES:
patent: 5027612 (1991-07-01), Terauchi
patent: 5823000 (1998-10-01), Takai
patent: 6038871 (2000-03-01), Gutierrez et al.
patent: 6126405 (2000-10-01), Kawaguchi et al.
patent: 5-223357 (1993-08-01), None
patent: 7-19630 (1995-01-01), None
Ban Takashi
Fujii Toshiro
Okabe Takanori
Kabushiki Kaisha Toyoda Jidoshokki Seisakusho
Morgan & Finnegan L.L.P.
Tanner Harry B.
LandOfFree
Air conditioning systems does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Air conditioning systems, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Air conditioning systems will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2512859