Fluid handling – Systems – With flow control means for branched passages
Reexamination Certificate
2000-03-24
2002-04-09
Fox, John (Department: 3753)
Fluid handling
Systems
With flow control means for branched passages
C137S119030, C137S119100, C251S030040
Reexamination Certificate
active
06367506
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to switch valves used in air-conditioner refrigerant circuits, and more particularly, to switch valves used in refrigerant circuits having hot gas circuits.
A typical automotive air-conditioner refrigerant circuit includes a hot gas circuit. When the air conditioner warms the passenger compartment, heated and pressurized refrigerant gas (hereinafter referred to as “hot gas”) circulates in the hot-gas circuit.
FIG. 5
shows a prior art refrigerant circuit of an automotive air-conditioner. The refrigerant circuit includes a compressor
10
, a condenser
11
, a receiver
12
, a check valve
9
, a depressurizing device (expansion valve)
13
, an evaporator
14
, and an accumulator
15
. These constituents are arranged in this order and connected with each other by a pipe
16
to define the refrigerant circuit. The compressor
10
is actuated by an engine (not shown).
A first electromagnetic valve
17
is located in a section of the pipe
16
between the compressor
10
and the condenser
11
. A first bypass pipe
20
constitutes a hot gas circuit and has an inlet
20
a
connected to a section of the pipe
16
between the compressor
10
and the first electromagnetic valve
17
. The first bypass pipe
20
also has an outlet
20
b
connected to a section of the pipe
16
between the depressurizing device
13
and the evaporator
14
. Another depressurizing device
22
is provided in the first bypass pipe
20
. A second electromagnetic valve
18
is located in the first bypass pipe
20
upstream from the depressurizing device
22
.
The depressurizing device
22
depressurizes the hot gas discharged from the compressor
10
to a predetermined value.
The depressurized hot gas is then sent to the evaporator
14
.
In this case, it is preferred that the pressure in the first bypass pipe
20
be 1.47 MPa upstream of the depressurizing device
22
and 0.20 to 0.39 MPa downstream of the depressurizing device
22
.
A second bypass pipe
40
has an inlet connected to the section of the pipe
16
between the compressor
10
and the first electromagnetic valve
17
. The second bypass pipe
40
further has an outlet connected to a section of the pipe
16
between the accumulator
15
and the compressor
10
. Another depressurizing device
42
is provided in the second bypass pipe
40
. A third electromagnetic valve
41
is provided in the second bypass pipe
40
and located upstream from the depressurizing device
42
. The first to third electromagnetic valves
17
,
18
,
41
are controlled by a controller
100
constituted by, for example, a computer.
When the air conditioner cools the passenger compartment, the controller
100
opens the first electromagnetic valve
17
and closes the second and third electromagnetic valves
18
,
41
. Refrigerant thus circulates in the pipe
16
without passing through the bypass pipes
20
,
40
. Specifically, the compressor
10
sends high-pressure gas to the condenser
11
. The condenser
11
condenses the gas and sends the gas to the evaporator
14
via the receiver
12
, the check valve
9
, and the depressurizing device
13
. The evaporator
14
cools the ambient air by transferring heat between the ambient air and the condensed refrigerant. The heat transfer evaporates refrigerant, and the evaporated refrigerant gas returns to the compressor via the accumulator
15
.
The depressurizing device
13
adjusts the amount of the refrigerant sent by the condenser
11
to the evaporator
14
in accordance with the temperature or pressure at the outlet of the evaporator
14
. The accumulator
15
accumulates liquid refrigerant, or refrigerant remaining non-evaporated after passing through the evaporator
14
. This structure prevents the liquid refrigerant from returning to the compressor
10
.
When the air conditioner warms the passenger compartment, the controller
100
first performs a warm-up procedure for the warming operation. That is, the controller
100
closes the first and second electromagnetic valves
17
,
18
and opens the third electromagnetic valve
41
. The refrigerant gas from the compressor
10
thus returns to the compressor
10
via the second bypass pipe
40
. The depressurizing device
42
in the second bypass pipe
40
increases the pressure of the refrigerant gas exiting the compressor
10
(the discharge pressure of the compressor
10
).
When a predetermined time elapses after the controller
100
starts the warming operation, or when the discharge pressure of the compressor
10
reaches a predetermined value, the controller
100
opens the second electromagnetic valve
18
and closes the third electromagnetic valve
41
. Accordingly, the air conditioner initiates a normal procedure for the warming operation. That is, the refrigerant gas discharged from the compressor
10
, or hot gas, is sent to the evaporator
14
via the first bypass pipe
20
. The evaporator
14
warms the ambient air by transferring heat between the ambient air and the hot gas. The refrigerant gas is thus cooled due to the heat transfer and is returned to the compressor
10
through the accumulator
15
. In this manner, the refrigerant gas circulates in the hot gas circuit, which is formed by the first bypass pipe
20
, when the air conditioner performs the normal warming procedure.
As described, in the prior art refrigerant circuit shown in
FIG. 5
, three electromagnetic valves
17
,
18
,
41
are used for switching the refrigerant circuit between the cooling operation and the warming operation. This complicates the circuit configuration and the circuit control procedure, thus raising the manufacturing cost and the power consumption.
SUMMARY OF THE INVENTION
It is an objective of the present invention to provide a switch valve simplifying configuration of a refrigerant circuit having a hot gas circuit.
To achieve the above objective, a switch valve according to the present invention comprises a single valve housing. A first passage is formed in the valve housing to permit a fluid to flow into the valve housing. A second passage is formed in the valve housing to permit, at selected times, the fluid in the first passage to exit the valve housing. A third passage is formed in the valve housing to permit, at selected times, the fluid in the first passage to exit the valve housing. A first valve mechanism is incorporated in the valve housing for selectively connecting and disconnecting the first passage with the second passage in accordance with an external instruction. A second valve mechanism is incorporated in the valve housing for selectively connecting and disconnecting the first passage with the third passage in accordance with the difference between the pressure in the first passage and the pressure in the second passage.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
REFERENCES:
patent: 4270726 (1981-06-01), Hertfelder et al.
patent: 5299592 (1994-04-01), Swanson
Hirose Tetsuo
Takagi Noboru
Fox John
Pacific Industrial Company, Ltd.
Senterfitt Akerman
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