GB2435088A

GB2435088A - Air conditioning apparatus

Info

Publication number: GB2435088A
Application number: GB0615780A
Authority: GB
Inventors: Hirokuni Shiba
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2004-03-05
Filing date: 2006-08-08
Publication date: 2007-08-15
Anticipated expiration: 2025-03-03
Also published as: GB2435088B; GB0615780D0

Abstract

The present invention relates to a refrigeration circuit in an air conditioning apparatus, the refrigeration circuit including a compressor 1, an oil separator 27 arranged at a discharge portion of the compressor, a four-way valve 2, a condenser 3, an expansion valve 4, a fluid reservoir 5a, an evaporator 8, and an activated charcoal filler 17 in series with an electromagnetic valve 16. The circuit further including an oil return path 28, provided for returning oil separated by the oil separator to an intake portion of the compressor, and including the activated charcoal filter and electromagnetic valve 16 within this return circuit. The air conditioning apparatus may function such that refrigerant flows through the activated charcoal filter for a predetermined time period, which may be at an initial heating start-up period and/or during normal operation. The invention permits installation of a new outdoor unit and a new indoor unit to preinstalled fluid lines.

Description

AIR CONDITIONING APPARATUS

The present invention provides an air conditioning apparatus that can be installed without cleaning existing lines, even under conditions in which debris, such as large quantities of dust from abrasion in the compressor, deteriorated oil, and strong acids, remains in the indoor and outdoor connecting lines for the air conditioning apparatus.

A refrigeration cycle in a first conventional air conditioning apparatus includes a compressor, a fourway valve, a condenser, a first electric expansion valve, a fluid reservoir mechanism, a second electric expansion valve, a fluid line, an evaporator, a gas line, and a low-pressure-side heat exchanger, which con.figure a refrigerant circuit. A plurality of strainers is included in the circuit. The mesh of the strainers used usually is 30 to 100 mesh, in order to protect distribution capillary tubes in the condenser and in the evaporator, apd to protect the electric expansion valves.

If an outdoor unit is operable, in that the compressor has no history of breaking down, then the refrigerant oil remaining in the reusable extension lines is controlled to be less than a reference level by forcibly carrying out a cooling operation, and the old refrigerant is recovered into the outdoor unit by a pump-down operation. Otherwise, if the compressor has a history of breaking down, the old refrigerant is recovered using a special recovery device, and then the indoor and outdoor units are removed (e.g., see Patent Document 1).

Moreover, a refrigeration cycle in a second conventional air conditioning apparatus includes a compressor, a four-way valve, a condenser, an electric expansion valve, a fluid line, an evaporator, a gas Line, an accumulator, a foreign matter storage in which activated charcoal and molecular sieves are encapsulated, and a plurality of strainers installed in the circuit. For the strainers, likewise as above, 30 to 100 mesh is used. (e.g., see Patent Document 2).

[Patent Document 1] Japanese Patent Laid-Open No. 174091/2001 (Fig. 1) [Patent Document 2] Japanese Patent Laid-Open No. 279199/2003 (Fig. 1) Next, in the conventional refrigeration cycles in air conditioning apparatuses, because compressor failures occur due to strong acids such as organic acids or inorganic acids that remain in the existing lines, or a large amount of abrasion dust and deteriorated refrigerant oil obstruct the strainers installed in the refrigeration cycle, when the compressor breaks down, installation of a new air conditioning apparatus is carried out after cleaning the existing lines with a scrubber using a cleaning agent such as R22 to remove foreign matter. But there has been a problem in that, even if the installation is in a situation in which, as described above, the old indoor unit and the old outdoor unit can be uninstalled relatively easily, it takes around three man-hours to complete the installation, and working costs become enormous when the compressor breaks down.

The present invention is made to resolve such a problem, arid aims to efficiently collect foreign matter such as dust from abrasion in the compressor and deteriorated refrigerant oil that remains in the existing line.

An air conditioning apparatus relevant to the present invention includes a refrigeration cycle in which a plurality of strainers is disposed within a refrigerant circuit along which a compressor, a fourway valve, a condenser, a first electric expansion valve, a fluid reservoir mechanism, a second electric expansion* valve, a fluid line, an evaporator, and a gas line are also disposed, distributed in that order back to the four-way valve; wherein a drying filter for trapping foreign matter, and an activated charcoal filter for trapping organic acids, inorganic acids, chlorine content, or the like are disposed between the second electric expansion valve and the fluid line.

Moreover, another air conditioning apparatus relevant to the present invention includes a refrigeration cycle in which a plurality of strainers is disposed within a refrigerant circuit along which a compressor, a four-way valve, a condenser, a first electric expansion valve, a fluid reservoir mechanism, a second electric expansion valve, a fluid line, an evaporator, and a gas line, distributed in that order back to the four-way valve, and a low-pressure-side heat exchanger are also disposed; wherein a drying filter for trapping foreign matter, and an activated charcoal filter for trapping organic acids, inorganic acids, chlorine content, or the like are disposed between the second electric expansion valve and the fluid line.

The air conditioning apparatus relevant to the present invention includes a refrigeration cycle in which a plurality of strainers is disposed within a refrigerant circuit along which a compressor, a fourway valve, a condenser, a first electric expansion valve, a fluid reservoir mechanism, a second electric expansion valve, a fluid line, an evaporator, and a gas line are also disposed, distributed in that order back to the fourway valve, wherein a drying filter for trapping foreign matter, and an activated charcoal filter for trapping organic acids, inorganic acids, chlorine content, or the like are disposed between the second electric expansion valve and the fluid line; whereby it is possible to provide an air conditioning apparatus that can be installed without causing compressor failures due to strong acids or chlorine content, or obstruction of the strainers due to abrasion dust or deteriorated refrigerant oil, without cleaning existing lines, and to

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reduce tjme, burdens, and costs, when installing a new unit.

Moreover, the air conditioning apparatus relevant to the present invention includes a refrigeration cycle in which a plurality of strainers is disposed within a refrigerant circuit along which a compressor, a four-way valve, a condenser, a first electric expansion valve, a fluid reservoir mechanism, a second electric expansion valve, a fluid line, an evaporator, a gas line, the four-way valve, and a low-pressure-side heat exchanger in that order are connected in that order to be installed, wherein a drying filter for trapping foreign matter, and an activated charcoal filter for trapping organic acids, inorganic acids, chlorine content, or the like are disposed between the second electric expansion valve and the fluid line; whereby, not only foreign matter, such as spatters generated in manufacturing the compressor, and copper oxide generated in welding the heat exchanger or the lines, are prevented from jamming into refrigerant circuit components such as the four-way valve and the electric expansion valves, but also deteriorated refrigerant oil generated during a long-term operation and the like can be trapped, to enhance the reliability of the air conditioning apparatus.

The invention will be further described by way of example with reference to the accompanying drawings, in which. -Fig. 1 is a block diagram illustrating a refrigerant ci'.:uit in an air conditioning apparatus in Embodiment 1 Qf the invention.

Fig. 2 is a schematic cross-sectional diagran' illustratrng a drying

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fi.lter used for the refrigerant circuit in the air conditioning apparatus in Embodiment 1 of the invention.

Fig. 3 is a diagram illustrating a control image of each unit during the forcible initial heating operation for the air conditioning apparatus in Embodiment 1 of the invention.

Fig. 4 is a table listing thresholds for controlling each circuit component during the initial heating operation for the air conditioning apparatus in Embodiment 1 of the invention.

Fig. 5 is an installation flow chart when installing the air conditioning apparatus of the invention.

Fig. 6 is a block diagram illustrating a refrigerant circuit in an air conditioning apparatus in Embodiment 2 of the invention.

Fig. 7 is a diagram illustrating a control image of each unit during the forcible initial heating operation for the air conditioning apparatus in Embodiment 2 of the invention.

Fig. 8 is a block diagram illustrating a refrigerant circuit in an air conditioning apparatus in Embodiment 3 of the invention.

Fig. 9 is a diagram illustrating a control image of each unit during the forcible initial heating operation for the air conditioning apparatus in Embodiment 3 of the invention.

Fig. 10 is a block diagram illustrating a refrigerant circuit in an air conditioning apparatus in Embodiment 4 of the invention.

Fig. 11 is a diagram illustrating a control image of each unit during the forcible initial heating operation for the air conditioning apparatus in Embodiment 4 of the invention.

Embodiment 1.

Fig. 1 illustrates an example of the structure of a refrigerant circuit for an air conditioning apparatus in Embodiment 1 of the invention. In the figure, the refrigerant circuit is composed of a compressor 1, a four-way valve 2, a condenser 3, a first electric expansion valve 4, a fluid reservoir mechanism 5, a second electric expansion valve 6, a fluid line 7, an evaporator 8, a gas line 9, and a low-pressure-side heat exchanger 10. As for a plurality of strainers 11, a first strainer ha is installed between the condenser 3 and the first electric expansion valve 4, a second strainer lib is installed between the first electric expansion valve 4 and the fluid reservoir mechanism 5, a third strainer lic is installed between the fluid reservoir mechanism 5 and the second electric expansion valve 6, and a fourth strainer lid is installed between the gas line 9 and the four-way valve 2.

A drying filter main body 12 is installed between the second electric expansion valve 6 and the fluid line 7. The structure of the drying filter is illustrated in Fig. 2, in which a cylinder 12a and a pair of caps 12c for obstructing both openings of the cylinder 12a, each cap having a connecting hole 12b in the center, form a shell; inside of the shell, absorbent agents 12d such as activated alumina and molecular sieves for absorbing strong acids such as organic acids or inorganic acids are provided in the middle, and a fiber structure 12e such as glass wool surrounding the absorbing agents 12d is provided outside thereof both sides of these absorbing agents 12d and the fiber structure 12e such as glass wool are held by holding members 12g each having an opening and closing valve 12f in the center so as to form a refrigerant passageway 12h within the cylinder 12a and control valves 12i are provided at both-side intakes for the refrigerant passageway 12h, for controlling so that a refrigerant flow path 12j flowing in one direction along the refrigerant passageway 12h, through the fiber structure 12e and the absorbing agents 12d to the opening and closing valve 12f in the center of the holding member 12g, flows in through one connecting hole 12b and discharges from the other connecting hole 12b.

Here, the mesh of each strainer 11 installed in the circuit-the first strainer ha, the second strainer lib, the third strainer lie, and the fourth strainer lid-is usually 30 to 100 mesh, and, in order to trap minute foreign matter passing through the first strainer ha, the second strainer lib, the third strainer lie, and the fourth strainer lid and circulating in the circuit, the removal performance of foreign matter of the fiber structure 12e such as glass wool in the drying filter 12 is made higher than the removal performance of foreign matter of the first strainer ha, the second strainer ilb, the third strainer lie, and the fourth strainer lid, and 150 to 300 mesh is selected. It is preferable to select, for example, 200 mesh.

Thus, by making the filtering performance of the drying filter 12 higher than the filtering performance of the first strainer ha, the second strainer lib, the third strainer lie, and the fourth strainer lid in the circuit, foreign matter that is larger than 100.tm and that obstructs the first strainer ha, the second strainer lib, the third strainer lie, and the fourth strainer lid in the circuit can be trapped by the drying filter 12.

In addition, the drying filter 12 adopts a mechanism that, given that refrigerant flows in the direction A, for example, using a plurality of opening and closing valves 12f and control valves 12i, the refrigerant flows in the direction from the outside to the inside, whereby foreign matter that has once been trapped by the drying filter 12 cannot outflow into the circuit again.

Moreover, because the absorbing agents 12d such as activated alumina packed in the drying filter 12 sometimes absorb additive agents in refrigerant oil, it is preferable, for example, that the absorbing agents are maintained to be less than 25 g, for instance, around 10 g, with respect to 1000 cc of compressor refrigerant oil, which is encapsulated in the air conditioning apparatus according to the invention.

Furthermore, a pair of check valves 13 are disposed in series facing each other. One end of the pair is connected between the first strainer ha and the first electric expansion valve 4, and the other end is connected to one end of a first bypass 14 that is formed by connecting the third strainer lic and the second electric expansion valve 6.

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Moreover, one end of a second bypass 15 is connected between the pair of check valves for the first bypass 14, and the other end is soaked in the fluid reservoir mechanism 5. Along the second bypass, an electromagnetic valve 16, and an activated charcoal filter 17 for trapping organic acids, inorganic acids, and chlorine content are installed in series.

Because the activated charcoal filter 17 can more efficiently absorb strong acids or chlorine content when fluid refrigerant passes, it is preferable to install a squeezing unit 18 such as capillary tubes between the charcoal filter 17 and the fluid reservoir mechanism 5.

Furthermore, an indoor intake temperature sensor 19 and an indoor fan 20 are provided in an indoor unit, and an outdoor intake temperature sensor 21 and an outdoor fan 22 are provided in an outdoor unit. A fluid-side stopping valve 23 is provided between the fluid line 7 and the drying filter 12, and gasside stopping valve 24 is provided between the gas line 9 and the fourth strainer lid.

In addition, because strong acids, chlorine content, or the like are firmly adhered to the existing lines used for the refrigeration cycle whose compressor has broken down, and are likely to flake away when the air conditioning apparatus runs for a long time, it is preferable to control the first electric expansion valve 4 or the second electric expansion valve 6, and the electromagnetic valve 16, to be opened for a given time after a certain period of time, for example, around 30 minutes open every 1000 hours, so that the refrigerant can pass through the-activated charcoal filter 17.

Because foreign matter that remains in the existing lines, such as dust from abrasion in the compressor, deteriorated refrigerant oil, strong acids, and chlorine content, dissolve in the refrigerant, or move together with the refrigerant, the amount of the foreign matter depends on the amount of the refrigerant remaining in the existing lines when a malfunction occurs, and a large amount of foreign matter remains in the fluid line 7 side. Accordingly, so as not to let the foreign matter outflow into the refrigerant circuit, in the air conditioning apparatus according to the invention, a heating operation is forcibly carried out for the initial operation so that the drying filter 12 installed between the second electric expansion valve 6 and the fluid line 7 can trap the foreign matter Fig. 3 is a diagram illustrating a control image of each unit during the forcible initial heating operation for the air conditioning apparatus in Embodiment 1 of the invention. As a method of forcibly carrying out the heating operation, the number of compressor on/off operations is monitored by a control unit 25, for example, and, when the number of onJoff operations is zero, an intake temperature acquired by an indoor intake sensor 19 provided in the indoor unit is only stored in the control unit, and the intake temperature is made lower than the preset temperature; whereby in the initial operation, a command for a trial heating operation for less than 30 minutes, for example 10 minutes, must be transmitted to the fourway valve 2 by pressing an indoor remote controller, to forcibly carry out a heating operation, and when the duration of the trial heating operation is completed,

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the opóration is automatically changed to an operating mode that was set when the indoor remote controller was pressed.

Here, a compressor operation accumulated time can substitute for the number of compressor on/off operations monitored by the control unit 25, and when the compressor operation accumulated time is zero, the initial forcible heating operation is carried out in the same manner. The strong acids and the chlorine content are controlled so as to pass through the activated charcoal filter 17 by transmitting, in the initial heating operation, from the control unit commands for totally closing the second electric expansion valve 6 and for opening the electromagnetic valve 16.

In addition, by forcibly carrying out the initial trial heating operation during an intense heat season, a temperature rise and a pressure rise of discharging gas from the compressor 1 are concerned. For example, an indoor temperature and an outdoor temperature are detected using the indoor intake temperature sensor 19 and the outdoor intake temperature sensor 21. Then, for example, according to thresholds of the indoor temperature and the outdoor temperature in the initial heating operation of the air conditioning apparatus illustrated in Fig. 4, which indicates thresholds for the control of each circuit unit, control modes of each circuit unit for suppressing the temperature rise and the pressure rise of the discharging gas are changed, and control modes of the compressor 1, the indoor fan 20, and the outdoor 22 are changed according to indoor/outdoor temperature conditions. -Here, a threshold table illustrated in Fig. 4 described above will be explained. As for detected temperatures detected by the indoor intake temperature sensor 19 and the outdoor intake temperature sensor 20, in a case in which, for example, the indoor temperature is 25 degrees C or lower, and the outdoor temperature is 30 degrees C or lower; the compressor is controlled normally, the indoor fan is stopped, and the outdoor fan is controlled normally. In a case in which the indoor temperature is 25 degrees C or higher, and the outdoor temperature is 30 degrees C or lower; the compressor is controlled normally, the indoor fan sends a minimum air volume, and the outdoor fan sends a medium air volume. In a case in which the indoor temperature is 25 degrees C or lower, and the outdoor temperature is 30 degrees C or higher, the compressor is controlled normally, the indoor fan sends the minimum air volume, and the outdoor fan is stopped. In a case in which the indoor temperature is 25 degrees C or higher, and the.outdoor temperature is 30 degrees C or higher; the compressor is operated in the minimum frequency, the indoor fan sends a medium air volume, and the outdoor fan is stopped.

In addition, by measuring in advance what temperature or pressure values are outputted from a plurality of other temperature sensors or pressure sensors (none of them is illustrated) installed in the indoor unit and the outdoor unit under the conditions of the indoor/outdoor temperatures that are assumable in operations, and by inputting the measured values as thresholds, the indoor intake temperature sensor 19 and the outdoor intake temperature sensor 20 can be replaced with the temperature sensors or the pressure sensors described above.

Because, during the initial heating operation, a relatively small amount of foreign matter remaining in the gas line 9 passes through the indoor unit, it is preferable that a strainer 26 in an indoor distributor is not installed, or the mesh of the strainer used is coarser than 50 mesh, which can never be obstructed by foreign matter.

Next, an installation flow of the present invention will be described using Fig. 5. Firstly, in the figure, the process flow starts in Step 1. In Step 2, when the compressor has no history of breaking down and the outdoor unit is operable, "YES" is selected. Next, in Step 3, the fluidside stopping valve 2 is closed, and a pump-down operation for recovering the refrigerant into the outdoor-unit side is carried out, to recover the old refrigerant in the old refrigeration cycle into the outdoor unit. Then the gas-side stopping valve 24 is closed.

Next, in Step 4, the old indoor unit and the old outdoor unit are removed, and then inStallation of a new indoor unit and a new outdoor unit is carried out. After that, likewise as in conventional air conditioning apparatuses, vacuuming is carried out for thirty minutes in Step 5, the fluidside stopping valve 23 and the gas-side stopping valve 24 are opened in Step 6 to add and charge refrigerant as required, and a trial operation, which is a forcible heating operation in the present invention, is carried out in Step 7. At the end, in Step 8, the operation moves into an automatic operation preset by a remote controller, and the process flow ends in Step 9.

Meanwhile, in Step 2 in Fig. 5, when the compressor has a history of breaking down and the outdoor unit is not operable, the process flow moves to "NO". Next, in Step 10, when the compressor has broken down, the pumpdown operation cannot be carried out; whereby the fluid-side stopping valve 23 and the gas-side stopping valve 24 are closed, and the old refrigerant in the old refrigeration cycle is recovered using a special recovery device. After that, in Step 11, the old indoor unit and the old outdoor unit are removed, and replaced with a new indoor unit and a new outdoor unit. After that, likewise as in conventional air conditioning apparatuses, Step 5, a step of vacuuming, through Step 9 are carried out.

However, even if the compressor has not broken down, when the operation time can be more reduced by closing the fluid-side stopping valve 23 and the gas-side stopping valve 24, and by carrying out the refrigerant recovery operation, "NO" can be selected in Step 2 so that Step 10 to carry out the refrigerant recovery operation.

Embodiment 2.

Fig. 6 illustrates an example of the structure of a refrigerant circuit for an air conditioning apparatus in Embodiment 2 of the invention.ln the figure, the refrigerant circuit is composed of a compressor 1, a four-way valve 2, a condenser 3, a first electric expansion valve 4, a fluid reservoir mechanism 5, a second electric expansion valve 6, a fluid line 7, a drying filter 12, an evaporator 8, a gas line 9, and a low-pressure-side heat exchanger 10. As for a plurality of strainers 11, a first strainer ha is installed between the condenser 3 and the first electric expansion valve 4, a second strainer lib is installed between the first electric expansion valve 4 and the fluid reservoir mechanism 5, a third strainer hic is installed between the fluid reservoir mechanism 5 and the second electric expansion valve 6, and a fourth strainer lid is installed between the gas line 9 and the fourway valve 2.

In addition, by disposing an oil separator 27 to a compressor intake pipe lb side at one end of a compressor discharge pipe la between the compressor 1 and the four-way valve 2, and by installing an oil returning circuit 28 along which an electromagnetic valve 16, an activated charcoal filter 17, and a squeezing unit 18 such as capillary tubes in that order are disposed in series, it is possible to achieve the same effects as in the refrigeration circuit described in Embodiment 1. Likewise as in Embodiment 1, it is preferable to open the electromagnetic valve 16 for a given time after a certain period of time so that the refrigerant flows into the activated charcoal filter 17.

Fig. 7 is a control image diagram illustrating commands to each unit during the initial heating operation for the air conditioning apparatus in Embodiment 2 of the invention. As a method of forcibly carrying out the heatin operation, the number of compressor on/off operations is monitored by a control unit 25, for example, and, when the number of on/off operations is zero, an intake temperature acquired by an indoor intake sensor 19 provided in the indoor unit is only stored in the control unit, and the intake temperature is made lower than the preset temperature; whereby in the initial operation, a command for a trial heating operation for less than 30 minutes, for example 10 minutes, must be transmitted to the fourway valve 2 by pressing an indoor remote controller (not illustrated), to forcibly carry out a heating operation, and when the duration of the trial heating operation is completed, the operation is automatically changed to an operating mode that was set when the indoor remote controller was pressed.

Here, a compressor operation accumulated time can substitute for the number of compressor on/off operations monitored by the control unit 25, and when the compressor operation accumulated time is zero, the initial forcible heating operation is carried out in the same manner. The strong acids and the chlorine content are controlled so as to pass through the activated charcoal 8lter 17 by transmitting, in the initial heating operation, from the control unit 25 commands for controlling the second electric expansion valve 6 normally and for opening the electromagnetic valve 16.

Thus, likewise as in Embodiment 1, by determining the outdoor intake temperature, the operation commands as in Embodiment 1 described above are transmitted to the compressor 1, the four-way valve 2, the electromagnetic valve 14, the indoor fan 20, and the outdoor fan 22, to carry out the initial heating operation.

Embodiment 3.

Fig. 8 illustrates an example of the structure of a refrigerant circuit for an air conditioning apparatus in Embodiment 3 of the invention. In the figure, the refrigerant circuit is composed of a compressor 1, a fourway valve 2, a condenser 3, a check-valve bridge circuit 29, a first electric expansion valve 4, a fluid reservoir mechanism 5, a second electric expansion valve 6, a fluid line 7, an evaporator 8, a gas line 9, and a low-pressure-side heat exchanger 10. As for a plurality of strainers, a first strainer ha is installed between the condenser 3 and the check-valve bridge circuit 29, a second strainer lib is installed between the first electric expansion valve 4 and the fluid reservoir mechanism 5, a third strainer hic is installed between the fluid reservoir mechanism 5 and the second electric expansion valve 6, and a fourth strainer lid is installed between the gas line 9 and the four-way valve 2.

In addition, by disposing in series an electromagnetic valve 16, an activated charcoal filter 17, and capillary tubes 18, along a second bypass 30 bypassing the first electric expansion valve 4, it is possible to achieve the same effects as in the refrigeration circuit in Embodiment 1 described above.

Likewise as in Embodiment 1 described above, it is preferable to open the electromagnetic valve 16 for a given time after a certain period of time so that the refrigerant flows into the activated charcoal filter 17.

Fig. 9 is a control image diagram illustrating commands to each unit during the initial heating operation for the air conditioning apparatus in Embodiment 3 of the invention. As a method of forcibly carrying out the heating operation, the number of compressor on/off operations is monitored by a control unit 25, for example, and, when the number of on/off operations is zero, an intake temperature acquired by an indoor intakesensor 19 provided in the indoor unit is only stored in the control unit, and the intake temperature is made lower than the preset temperature; whereby in the initial operation, a command for a trial heating operation for less than 30 minutes, for example 10 minutes, must be transmitted to the four-way valve 2 by pressing an indoor remote controller, to forcibly carry out a heating operation, and when the duration of the trial heating operation is completed, the operation is automatically changed to an operating mode that was set when the indoor remote controller was pressed.

Here, a compressor operation accumulated time can substitute for the number of compressor on/off operations monitored by the control unit 25, and when the compressor operation accumulated time is zero, the initial forcible heating operation is carried out in the same manner. The strong acids and the chlorine content are controlled so as to pass through the activated charcoal filter 17 by transmitting, in the initial heating operation, from the control unit 25 commands for totally closing the first electric expansion valve 4 and for opening the electromagnetic valve 16.

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In Embodiment 3 of the invention, by determining the outdoor intake temperature likewise as in Embodiment 1 described above, operation commands as in Embodiment 1 described above are transmitted to the compressor 1, the four-way valve 2, the electromagnetic valve 16, the indoor fan 20, and the outdoor fan 22, and a totally-closing command is transmitted to the first electric expansion valve 4, to carry out the initial heating operation.

Embodiment 4.

Fig. 10 illustrates an example of the structure of a refrigerant circuit for an air conditioning apparatus in Embodiment 4 of the invention. In the figure, the refrigerant circuit is composed of a compressor 1, a four-way valve 2, a condenser 3, an electric expansion valve 4, a fluid line 7, an evaporator 8, a gas line 9, and an accumulator 5a. A plurality of strainers 11 each is disposed between the condenser 3 and the electric expansion valve 4, between the electric expansion valve 4 and the fluid line 7, and between the gas line 9 and the four-way valve 2. An oil separator 27 is disposed between the compressor 1 and the four-way valve 2. The outlet 27a of the oil separator is connected midway the line between the accumulator 5a and the compressor 1. In addition, one end of an oil returning circuit 28, which is configured by disposing in series an electromagnetic valve 16, an activated charcoal Elter 17, and capillary tubes 18, is connected to the outlet 27a of the oil separator 27, and the other end is connected midway the line between an accumulator 5a side connecting portion 27b of the oil separator 27 andthe compressor 1.

In the refrigerant circuit in the air conditioning apparatus of the invention, it is possible to achieve the same effects as in the refrigerant circuit in Embodiment 1 described above, and it is preferable to open the electromagnetic valve 16 for a given time after a certain period of time so that the refrigerant flows into the activated charcoal filter 17 likewise as in Embodiment 1 described above.

Fig. 11 is a control image diagram illustrating commands to each unit during the initial heating operation. As a method of forcibly carrying out the heating operation, the number of compressor on/off operations is monitored by a control unit 25, for example, and, when the number of on/off operations is zero, an intake temperature acquired by an indoor intake sensor 19 provided in the indoor unit is only stored in the control unit, and the intake temperature is made lower than the preset temperature; whereby in the initial operation, a command for a trial heating operation for less than 30 minutes, for example 10 minutes, must be transmitted to the four-way valve 2 by pressing an indoor remote controller, to forcibly carry out a heating operation, and when the duration of the trial heating operation is completed, the operation is automatically changed to an operating mode that was set when the indoor remote controller was pressed.

Here, a compressor operation aceumulated time can substitute for

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the number of compressor on/off operations monitored by the control unit 25, and when the compressor operation accumulated time is zero, the initial forcible heating operation is carried out in the same manner. The strong acids and the chlorine content are controUed so as to pass through the activated charcoal filter 17 by transmitting, in the initial heating operation, from the control unit 25 a command for opening the electromagnetic valve 16. -In the refrigerant circuit in the air conditioning apparatus of the invention, likewise as in Embodiment 1 described above, by determining the outdoor intake temperature, the operation commands are transmitted to the compressor 1, the fourway valve 2, the electromagnetic valve 16, the indoor fan 20, and the outdoor fan 22, to carry out the initial heating operation.

Claims

CLAIMS

1. An air conditioning apparatus comprising a refrigerant circuit including a compressor, an oil separator, a four-way valve, a condenser, an expansion unit, a liquid storage, a fluid line, an evaporator, and a gas line; wherein the refrigerant circuit includes an oil returning circuit, provided for returning oil separated by the oil separator, disposed at a discharge portion of the compressor, to an intake portion of the compressor; and an electromagnetic valve and an activated charcoal filter are connected in series along the oil returning circuit.

2. An air conditioning apparatus according to claim 1 wherein the heating operation of the air conditioning apparatus is performed for a predetermined period of time during the air conditioning apparatus' maiden operation, and the electromagnetic valve is opened to flow refrigerant through the activated charcoal filter during the maiden heating operation.

3. An air conditioning apparatus according to any of claim I or claim 2, wherein refrigerant is flowed through the activated charcoal filter for a predetermined time at predetermined intervals of time during normal operation.

4. An airconditioning apparatus comprising: an outdoor unit including a compressor, a four-way valve, a condenser, an expansion unit and a liquid storage; an indoor unit including an evaporator; a fluid line; and a gas line; wherein the air conditioni.ng apparatus is configured according to any of claims I through 3 for the hooking up of a new outdoor unit and a new indoor unit to a preinstalled fluid line and gas line. 23 -

Amendments to the claims have been filed as follows

CLAIMS

1. An air conditioning apparatus comprising a refrigerant circuit within which a plurality of strainers formed from mesh in order to remove foreign matter from circulating refrigerant are disposed, said refrigerant circuit including a compressor, an oil separator, a four-way valve, a condenser, an expansion unit, a liquid storage, a fluid line, an evaporator, and a gas line; wherein the refrigerant circuit includes an oil returning circuit, provided for returning oil separated by the oil separator, disposed at a discharge portion of the compressor, to an intake portion of the compressor; and an electromagnetic valve and an activated charcoal filter are connected in series along the oil returning circuit.

2. An air conditioning apparatus according to claim 1 wherein the heating operation of the air conditioning apparatus is performed for a predetermined period of time during the air conditioning apparatus' maiden operation, and the electromagnetic valve is opened to flow refrigerant through the activated charcoal filter during the maiden heating operation.

3. An air conditioning apparatus according to any of claim 1 or claim 2, wherein refrigerant is flowed through the activated charcoal filter for a predetermined time at predetermined intervals of time during normal operation.

4. An airconditioning apparatus comprising: an outdoor unit including a compressor, a four-way valve, a condenser, an expansion unit and a liquid storage; an indoor unit including an evaporator; a fluid line; and a gas line; wherein

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the air conditioning apparatus is configured according to any of claims 1 through 3 for the hooking up of a new outdoor unit and a new indoor unit to a preinstafled fluid line and gas line.

5. Air conditioning apparatus constructed and arranged to operate substantially as hereinijefore described with reference to and as illustrated in Figures 10 and 11.