JPH09138039A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner to prevent the occurrence of choking due to adhesion of sludge to a capillary tube. SOLUTION: In an air conditioner wherein a compressor, a four-way switching valve, a heat exchanger on the utilization side, a capillary tube 5, and a heat exchanger on the heat source side are connected together through a refrigerant pipe to form a refrigerating cycle and cooling heating operation is practicable through switching of the four-way valve, the capillary tube 5 is provided with a sludge removing mechanism 75 to remove sludge through slide of it over the inner surface of a pipe in response to the flow of a refrigerant, whereby choking due to sludge is prevented from occurring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner, and more particularly to an air conditioner in which a capillary tube is used as a fixed resistance to a refrigerant in a refrigerant circuit.

[0002]

2. Description of the Related Art A refrigeration cycle in an air conditioner of this type includes a compressor, a four-way switching valve, a use side heat exchanger, a pressure reducer,
A heat source side heat exchanger is configured by connecting a refrigerant pipe, and a configuration using a capillary tube that imparts a fixed resistance as a pressure reducer is known.

Conventionally, the capillary tube is connected to the refrigerant pipe by welding or brazing, and is not removable.

[0004]

In such a capillary tube, the diameter of the tube is sharply reduced, and due to such a rapid change, the capillary tube is rapidly increased in pressure and temperature to prevent metal or the like. There is a problem that sludge adheres and narrows or blocks the inlet of the capillary tube.

On the other hand, as the refrigerant filled in the refrigerant circuit,
Conventionally, R12 and R50 having a chlorine group were used, but since there is a potential for ozone layer depletion above the ground, R22 (chlorodifluoromethane) with a low chlorine group content and chlorine R32 (difluoromethane), R125 (pentafluoroethane), R1 not containing
34a (tetrafluoroethane) or a mixture thereof (hereinafter referred to as "HFC-based refrigerant") is used as an alternative refrigerant. When such an HFC-based refrigerant is used as the refrigerant, an ester-based lubricating oil, an ether-based lubricating oil, a mixed oil thereof or the like which is compatible with the HFC-based refrigerant is used as the lubricating oil.

However, ester-based lubricating oils and ether-based lubricating oils have high reactivity with water, and if water is present in the refrigerant circuit,
There is a problem that it is hydrolyzed to generate acid, alcohol, etc., and further reacts with worn metal ions to produce metal soap. The metal soap generated by such a reaction mixes in the refrigerant as sludge and adheres to the refrigerant circuit to narrow or block the flow path.

In particular, a capillary tube having a small tube diameter has a problem that it is apt to be clogged due to corrosion by a refrigerant or adhesion of sludge.

When the capillary tube is clogged, the function of the refrigerant circuit cannot be fulfilled and the air conditioner cannot be operated.

Therefore, the present invention is to solve the above-mentioned problems of the prior art and to provide an air conditioner capable of preventing clogging caused by sludge attached to the capillary tube.

[0010]

According to a first aspect of the present invention, a refrigeration cycle is formed by connecting a compressor, a four-way switching valve, a use side heat exchanger, a capillary tube, and a heat source side heat exchanger with a refrigerant pipe. Then, in the air conditioner that enables the cooling and heating operation by the use side heat exchanger by switching the four-way switching valve, the capillary tube adheres to the wall surface by sliding the inner surface of the capillary tube according to the flow of the refrigerant. The sludge removing mechanism for removing the sludge is provided.

According to the first aspect of the invention, when the flow of the refrigerant occurs, the sludge removing mechanism slides on the inner surface of the capillary tube and scrapes off the sludge attached to the inner surface of the capillary tube. . Therefore, sludge does not adhere to and accumulate on the capillary tube, and clogging of the capillary tube is reliably prevented.

According to a second aspect of the present invention, in the first aspect of the present invention, the sludge removing mechanism slides on the inner surface of the capillary tube, and a stopper that holds the sliding body in the capillary tube. And with.

According to the second aspect of the present invention, the sliding body is held in the capillary tube by the stopper.

According to a third aspect of the present invention, in the second aspect of the present invention, the stoppers are arranged on both end sides of the sliding body, and engage with the ends of the capillary tube when they are moved a predetermined distance. It prevents the sliding body from moving.

According to the third aspect of the present invention, the stopper is configured to engage with the end portion of the capillary tube, so that the sliding body can be reliably stopped and removed from the capillary tube with a simple structure. Can be stopped. That is,
The slide body can be held in the capillary tube with a simple structure.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an air conditioner according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a perspective view showing a general household air conditioner. This type of air conditioner is composed of a use side unit A arranged indoors and a heat source side unit B arranged outdoors, both of which are connected by a refrigerant pipe 300.

FIG. 2 is a refrigerant circuit diagram showing a refrigeration cycle of the air conditioner shown in FIG.

Reference numeral 1 denotes a compressor, which is composed of a motor section whose rotational speed is controlled at a variable speed by an inverter, and a compression section driven by this motor section. 2 is a muffler,
Vibration and noise due to pulsation during discharge of the refrigerant discharged from the compressor 1 are suppressed. A four-way switching valve 3 is for switching the flow of the refrigerant during the cooling / heating operation. Reference numeral 4 is a heat source side heat exchanger, and 5 is a capillary tube according to an embodiment of the present invention. 6 is a screen filter, 7
Is a use side heat exchanger, 8 is a muffler similar to the above-mentioned muffler, 9 is an accumulator, and 10 is an electromagnetic on-off valve, which are annularly connected by a refrigerant pipe as shown in FIG.

The refrigerant discharged from the compressor 1 is shown by a solid line arrow (cooling operation), a dotted line arrow (heating operation), and a solid line in accordance with the switching position of the four-way switching valve 3 and the opening / closing of the electromagnetic opening / closing valve 10. Like the dotted arrow (defrosting operation), the flow direction is determined according to the three modes. During cooling operation,
The refrigerant discharged from the compressor 1 is a compressor 1, a muffler 2, a four-way switching valve 3, a heat source side heat exchanger 4, a capillary tube 5, a screen filter 6, a use side heat exchanger 7, a muffler 8, a four-way switching valve. 3, accumulator 9, compressor 1
, The heat source side heat exchanger 4 functions as a condenser, and the use side heat exchanger 7 functions as an evaporator.
The air conditioning operation by becomes possible. During the heating operation, the refrigerant discharged from the compressor 1 is the compressor 1, the muffler 2, the four-way switching valve 3, the muffler 8, the use side heat exchanger 7, the scree filter 6, the capillary tube 5, the heat source side heat exchanger 4 , The four-way switching valve 3, the accumulator 9, and the compressor 1 are circulated in this order, the heat source side heat exchanger 4 functions as an evaporator, the use side heat exchanger 7 functions as a condenser, and heating operation by the use side heat exchanger 7 is performed. Will be possible. During the defrosting operation (when the refrigerant is circulating as in the heating operation), the electromagnetic opening / closing valve 10 is opened, and a part of the high-temperature refrigerant discharged from the compressor 1 is transferred to the heat source side heat exchanger 4. Is directly supplied to the heat source side heat exchanger 4 in order to raise the temperature of the heat source. As a result, the heat source side heat exchanger 4
The temperature rises and frost is less likely to form, and some defrosting is performed. When the defrosting operation does not function sufficiently (when the outside air temperature is particularly low), reverse cycle defrosting (the refrigerant circulates as in the cooling operation) is forcibly performed.

The diameter of the refrigerant pipe provided with the electromagnetic on-off valve 10 is smaller than that of a normal refrigerant pipe, and the amount of the refrigerant flowing is adjusted. However, the diameter is increased to increase the flow rate of a capillary tube or the like. An adjustment mechanism may be provided.

FIG. 3 is a control circuit diagram of the air conditioner.
The left side shows the control circuit of the utilization side unit A, and the right side shows the control circuit of the heat source side unit B with the dashed line in the center of FIG. 3 as the boundary. Both control circuits have power line 10
0 and the control line 200.

The user side unit A includes a rectifying circuit 11 and
A power supply circuit 12 for the motor, a power supply circuit 13 for the control, a motor drive circuit 15, a switch board 17,
The receiving circuit 18a, the display board 18, and the flap motor 1
9 and 9 are provided.

The rectifier circuit 11 rectifies 100V AC power supplied through the plug 10a and supplies DC power to the respective power supply circuits 12 and 13. The motor power supply circuit 12 adjusts the DC voltage supplied to the DC fan motor 16 to a voltage of 10 to 36V. This power supply circuit 1
Reference numeral 2 is a heat exchanger on the use side by a fan driven by the DC fan motor 16 by changing the rotation speed of the DC fan motor 16 by varying the DC voltage in the range of 10 to 36 V according to the signal sent from the microcomputer 14. This is for controlling the amount of conditioned air conditioned in 7 to be blown into the conditioned room.

The control power supply circuit 13 generates a DC voltage of 5V to be supplied to the microcomputer 14. The motor drive circuit 15 responds to a signal from the microcomputer 14 based on the rotational position information of the DC fan motor 16 to control the timing of switching the energization to the stator winding of the DC fan motor 16. Switch board 17
Is fixed to the operation panel of the use side unit A, and the switch board 17 is provided with an on / off switch, a trial run switch, and the like. The state of these switches is captured by the microcomputer 14 by key scanning.
The receiving circuit 18a is the wireless remote controller 6
The remote control signal from 0 (for example, ON / OFF signal, cooling / heating switching signal, room temperature setting signal, etc.) is received, demodulated, and transferred to the microcomputer 14.
The display board 18 dynamically lights an LED based on a signal from the microcomputer 14 to display an operating state of the air conditioner. The flap motor 19 functions to move the flap that is conditioned in the utilization side heat exchanger 7 and changes the blowing direction of the conditioned air blown by the fan.

Further, in this control circuit, a room temperature sensor 20 for measuring the room temperature, a heat exchanger temperature sensor 21 for measuring the temperature of the utilization side heat exchanger 7, and a room humidity are measured. Humidity sensor 22 of The measured values detected by these sensors are A / D converted and fetched by the microcomputer 14. The microcomputer 14 inputs these input information (acquisition information)
And sends a signal for determining the operating capacity of the four-way switching valve and the compressor 1 to the heat source side unit B through the serial circuit 23 and the terminal plate T3. Also, triac 2
6 and the heater relay 27 are controlled by the microcomputer 14 through the driver 24. By this, dehumidification operation (condition of refrigeration cycle used during cooling operation)
The electric power supplied to the reheating heater 25 used for the above is controlled stepwise.

Reference numeral 30 is an external ROM that stores specific data indicating the type and characteristics of the air conditioner. These specific data are taken out from the external ROM immediately after the plug 14a is connected to the outlet and power is supplied to start up the microcomputer 14. The microcomputer 14 does not input a command from the wireless remote controller 60 or detect the state of an ON / OFF switch or a trial run switch (operation will be described later) until the specific data is taken out from the external ROM 30.

Next, the control circuit of the heat source side unit B will be described.

In the heat source side unit B, the terminal board T'1
, T'2, T'3 are respectively connected to terminal plates T1, T2, T3 arranged in the use side unit A. Reference numeral 31 is a varistor connected in parallel to the terminal plates T'1 and T'2, 32 is a noise filter, 34 is a reactor, 35 is a voltage doubler rectifier circuit, and 36 is a noise filter.

Reference numeral 39 is a serial circuit for dispersing the control signal supplied from the user side unit A from the power line through the terminal board T'3, and the dispersed signal is transmitted to the microcomputer 41. Reference numeral 40 is a current detector, which detects the current supplied to the heat source side unit B by current transformation (CT) and converts it into a signal for the microcomputer 41. 42 is a constant voltage circuit for generating electric power for operating the microcomputer 41, 38 is a three-phase inverter circuit, which controls the electric power supplied to the compressor 1 based on a control signal from the microcomputer 41, and compresses it. Adjust the driving ability of unit 1. Three-phase inverter circuit 38
Connects six power transistors in the form of a three-phase bridge. Reference numeral 43 is a motor section for operating the compressor 1 of the refrigeration cycle, and 44 is a discharge side temperature sensor for detecting the temperature of the refrigerant discharged from the compressor 1.
45 is a fan motor, the speed of which is controlled in three stages,
The heat source side heat exchanger is arranged so that air can be sent to it. The four-way switching valve 3 and the solenoid valve 10 switch the refrigerant passages of the refrigeration cycle as described above. Further, in the heat source side unit B, an outdoor temperature sensor 48 for detecting the outdoor temperature is mounted near the air intake of the fan motor 45, and a heat exchanger temperature sensor 49 for detecting the temperature of the heat source side heat exchanger is provided on the heat source side. Installed in heat exchanger. The detection values obtained by these temperature sensors 48 and 49 are A / D converted by the microcomputer 41 and taken in.

Reference numeral 50 is an external ROM of the user side unit A.
It is an external ROM having the same function as 30. The specific data of the heat source side unit B is the same as that described for the external ROM 30, but is stored in the ROM 50.

The symbol F in each control circuit of the heat source side unit B and the use side unit A is a fuse.

Each of the microcomputers (control devices) 14 and 41 is a ROM that stores a program in advance,
A RAM that stores reference data and a CPU that calculates a program are stored in the same container (87C196MC (MC sold by Intel Corporation).
S-96 series) and the like can be used).

Next, the refrigerant will be described.

In the present embodiment, either a single refrigerant or a mixed refrigerant can be used as the refrigerant, and for example, R-410A or R-410B is used. R-410A is a binary mixed refrigerant, and R-32 is 5
It has a composition of 0 wt% and R-125 of 50 wt% and has a boiling point of -52.2 ° C and a dew point of -52.2 ° C. R-41
0B has 45wt% of R-32 and 55wt% of R-125
% Composition.

In the mixed refrigerant having such a composition, HCFC
-22 (R-22) compared with the conventional single refrigerant,
The discharge temperature of the compressor under certain conditions is HCF
6-22 ° C for C-22, 7 for R-410A
It is 3.6 ° C., and the condensation pressure is 17 for HCFC-22.
35 bar while 27.3 for R-410A
0 bar and evaporation pressure is 6.7 for HCFC-22
9 bar, whereas R-410A has 10.86
Since it has a characteristic of bar, the entire refrigerant circuit has a higher temperature and a higher pressure than in the case of using a conventional single refrigerant of HCFC-22, and internal corrosion of the refrigerant pipe and sludge are likely to occur.

As a refrigerant, R-410A or R-4
When an HFC-based refrigerant such as 10B is used, an ester-based lubricating oil, an ether-based lubricating oil, a mixed oil thereof or the like which is compatible with the HFC-based refrigerant is used as the lubricating oil. Ester-based lubricating oils and ether-based lubricating oils have high reactivity with water, and if water is present in the refrigerant circuit, they will hydrolyze,
It easily produces acids, alcohols, etc., and further reacts with worn metal ions to form metal soap. Then, the metal soap generated by such a reaction may be mixed in the refrigerant as sludge and adhere to the refrigerant circuit to narrow or block the flow path. In particular, a capillary tube having a narrow tube diameter is likely to be clogged with such sludge. Therefore, in the present embodiment, the capillary tube is provided with a sludge removing mechanism described later to prevent clogging due to sludge.

When a mixed refrigerant such as R-410A and R-410B is used, since the boiling points of the refrigerants of the respective components are close to each other, it is difficult for the refrigerant composition to change. There is no need to consider the problems such as temperature glide that occur. Therefore, it becomes easy to control the entire air conditioner during operation.

Next, the capillary tube 5 will be described with reference to FIG.

The size and shape of the capillary tube 5 are not particularly limited, but in the present embodiment, the main body 71 uses a straight thin tube, and the inner diameter D is 1.3 mm in the present embodiment. , The length L is 400 mm.

Stopper accommodating portions 73a and 73b are formed at both ends of the main body 71 of the capillary tube 5, and the stopper 77 of the sludge removing mechanism 75 is accommodated in the stopper accommodating portions 73a and 73b. There is. The stopper accommodating portions 73a and 73b have a diameter D of the main body 71.
It has a larger diameter E than the above, and accommodates the stopper 77 and limits the movement of the stopper 77.

A sludge removing mechanism 75 is provided in the capillary tube 5. This sludge removal mechanism 7
Reference numeral 5 is for removing sludge adhering to the inner wall of the capillary tube, and is composed of a rope-shaped sliding body 79 that slides in the capillary tube, and stoppers 77 provided at both ends of the sliding body 79. ing.

A part of the sliding body 79 comes into contact with the inner wall of the capillary tube 5 and slides to scrape off the sludge adhering to the inner wall of the tube. The sludge that has been stripped off is collected by the screen filter 6. In the present embodiment, the sliding body 79 uses a metal wire meandering in a corrugated shape, and a stainless steel wire is preferably used from the viewpoint of corrosion resistance and workability, but the capillary tube 5 is used.
It is preferable that a surface treatment is performed to prevent the inner wall of the pipe from being scraped. The corrugation of the sliding body 79 abuts the pipe inner peripheral wall at its curved portion, but if the corrugation is not formed two-dimensionally but one corrugated is formed three-dimensionally in various directions, the pipe inner peripheral wall is formed. Sludge can be removed by sliding around the entire circumference of the sludge.

The stopper 77 includes a stopper housing portion 73a,
The main body 7 of the capillary tube is housed in 73b.
1 is larger than the diameter D of 1, and the stopper storage portions 73a, 73
It has a radius R smaller than the diameter E of b and is held in the stopper accommodating portions 73a and 73b.

As shown in FIG. 5, the stopper 77 is provided with a large number of engaging projections 81 projecting on the sliding body 79 side on a circular plate.
The stopper 77 is prevented from moving by engaging with the inner wall surfaces 83 of a and 73b. Further, a hole 85 for a refrigerant passage is formed in the stopper 77 to allow the refrigerant to flow. In the present embodiment, the holes for the refrigerant passages are formed so as to be surrounded by the ribs 87 that are formed radially, but may be formed by punching out a disc.

The resistance in the capillary tube 5 is given to the entire capillary tube 5 including the sludge removing mechanism composed of the sliding body 79 and the stopper 77.

Next, the operation of the sludge removing function 5 will be described.

For example, during the cooling operation, the refrigerant flows through the capillary tube 5 as shown by the arrow in FIG. Then, the stopper 77 and the sliding body 79 are pushed by the flow of the refrigerant, so that the entire sludge removing mechanism 75 is stopped in the stopper accommodating portion 73b.
Move to the side. However, after moving a predetermined distance, as shown in FIG.
7, the engaging projection 81 comes into contact with the wall surface of the stopper housing portion 73a and stops.

In this case, in the capillary tube 5, not only the main body 71 of the thin tube but also the sludge removing mechanism 75 acts as a resistance of the refrigerant. Therefore, even if the capillary tube 5 is not formed in a spiral shape but is formed in a linear shape, it is possible to give a resistance of a sufficient value.

When the stopper 77 is in contact with the inner wall surface as shown in FIG. 4, the sludge removing mechanism 75 does not move completely, and the turbulence of the flow of the refrigerant and the uneven resistance are caused. Even when the sludge removing mechanism 75 rotates or swings, the sliding body 79 can rotate (or swing) in the capillary tube 71 and slide on the inner wall surface of the capillary tube to scrape off the sludge adhering thereto.

On the other hand, during the heating operation, the refrigerant flows through the capillary tube 5 on the side opposite to that during the cooling operation, that is, opposite to the arrow in FIG. Therefore, the stopper 77 is pushed by the flow of the refrigerant against the flow in the direction opposite to that during the cooling operation, and the sludge removing mechanism 75 as a whole is now in the stopper accommodating portion 73a.
Move to the side. However, when the stopper 77 on the side of the stopper accommodating portion 73b has moved a predetermined distance, the engaging projection 81 thereof comes into contact with the wall surface of the stopper accommodating portion 73b and stops.

That is, when the cooling operation is switched from the cooling operation to the heating operation and the flow of the refrigerant is reversed, the sludge removing mechanism 75 moves in accordance with the flow of the refrigerant, so that the sliding body 79 slides in the capillary tube 5. To remove the fludge attached to the inner wall of the pipe.

The sliding body 79 also removes the sludge adhering to the inner wall of the pipe by the rotation and swing as described above.

Next, another embodiment of the present invention will be described with reference to FIGS. In other embodiments described below, the same parts as those in the above-described embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

In the sludge removing mechanism 75 shown in FIG. 6, the sliding body 79 has a coil shape instead of a wave shape. Even with such a coil shape, the same effect as that of the above-described embodiment can be obtained.

In the sludge removing mechanism 75 shown in FIG. 7, the sliding body 93 is formed in a brush shape in which an infinite number of whiskers 95 are provided. Since the whiskers 95 are required to have a predetermined rigidity, a metal material is preferable. By thus forming the sliding body 93 in the shape of a brush, it is possible to reliably remove sludge attached to the entire circumference of the inner wall of the capillary tube.

FIG. 8 shows another stopper 77. In this embodiment, a hole 85 for a refrigerant passage is formed by punching a disk. In this way, the hole 85 for the refrigerant passage can be easily formed by punching the disk. Incidentally, this stopper is provided with four engaging projections 81.

The present invention is not limited to the above-described embodiment, and can be variously modified without departing from the gist of the present invention.

For example, the stopper for holding the sliding body in the capillary tube is not limited to being held in the stopper accommodating portion, but both ends of the sliding body 79 may be fixed to the ends of the main body 71, respectively. . However, in this case as well, it is desirable that the sliding body 79 be configured to be expandable and contractable so as to move or sway in response to the flow of the refrigerant.

[0060]

According to the first aspect of the invention, even if sludge adheres to the inner surface of the capillary tube, when the flow of the refrigerant occurs, the sludge removing mechanism slides on the inner surface of the capillary tube. Then, scrape off the sludge attached to the inner surface of the capillary tube. Therefore, according to the invention as set forth in claim 2, sludge can be surely prevented without depositing and depositing sludge on the capillary tube. Since the stopper is provided, the sliding body can be held in the capillary tube.

According to the third aspect of the present invention, the stopper is configured to engage with the end portion of the capillary tube, so that the sliding body can be reliably stopped and removed from the capillary tube with a simple structure. Can be stopped. That is, the sliding body can be held in the capillary tube with a simple structure.

[0062]

[Brief description of the drawings]

FIG. 1 is a perspective view of an air conditioner to which the present invention is applied.

FIG. 2 is a refrigerant circuit diagram of the air conditioner shown in FIG.

FIG. 3 is a control circuit diagram of the air conditioner shown in FIG. 1.

FIG. 4 is a cross-sectional view showing a schematic configuration of a capillary tube.

5 is a perspective view of the stopper shown in FIG. 4. FIG.

FIG. 6 is a plan view showing a configuration of a sludge removing mechanism according to another embodiment.

FIG. 7 is a plan view showing a configuration of a sludge removing mechanism according to still another embodiment.

FIG. 8 is a perspective view of a stopper according to another embodiment.

[Explanation of symbols]

 1 Compressor 3 Four-way switching valve 4 Heat source side heat exchanger 5 Capillary tube 75 Sludge removal mechanism 77 Stopper 79 Sliding body

Front page continuation (72) Inventor Shinji Mikiyasu 2-5-5 Keihan Hon-dori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Takahiro Suzuki 2-5-5 Keihan-hondori, Moriguchi-shi, Osaka Sanyo Inside Electric Co., Ltd. (72) Inventor Katsuyuki Tsuno 2-5-5 Keihan Hon-dori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Norio Akutagawa 2-5-5 Keihan-hondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (3)

[Claims] 1. A compressor, a four-way switching valve, a utilization side heat exchanger,
A capillary tube, a heat source side heat exchanger are connected by a refrigerant pipe to form a refrigeration cycle, and by switching the four-way switching valve, in an air conditioner that enables cooling and heating operation by the use side heat exchanger, in the capillary tube Is an air conditioner characterized by comprising a sludge removing mechanism for removing sludge adhering to the wall surface by sliding on the inner surface of the pipe in accordance with the flow of the refrigerant. 2. The air conditioner according to claim 1, wherein the sludge removing mechanism includes a sliding body that slides on the inner surface of the capillary tube, and a stopper that holds the sliding body in the capillary tube. Machine. 3. The stopper is arranged at both ends of the sliding body, and engages with an end of the capillary tube to prevent the sliding body from moving when each of the stoppers moves a predetermined distance. Air conditioner described.