JPH10170055A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an occurrence of phenomenon of dew formation at an indoor device operation of which is stopped by a method wherein when a transmission of a control signal is stopped, a drain pump is driven for a predetermined period of time from the stop of transmission of this control signal so as to perform a drain water discharging treatment. SOLUTION: Even after the stop of transmission of an over-flow water sensing signal from a switch section 31b, a control section 33 successively controls a motor 36, continues to drive a main body 35 of a pump for a predetermined period of time and drain water kept in a drain pan 30 is further discharged through a discharging pipe 37 and the like. Then, after elapsing of a predetermined period of time, the control section 33 controls the motor 36 to terminate a driving of the main body 35 of the pump, i.e., the drain water discharging treatment. As a result, drain water within the drain pan 30 is not accumulated at an operation surface position of the float section 31a of a flat switch 31, but present near the bottom surface of the drain pan 30, resulting in that it is possible to eliminate occurrence of phenomenon of dew formation caused by evaporation or cooling of the drain water and so to prevent water leakage at an indoor device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner provided with means for discharging drain water using a float switch and a drain pump.

[0002]

2. Description of the Related Art In an air conditioner, a drain water discharging process for discharging drain water generated during an evaporative cooling operation of an indoor unit is performed.

For example, during cooling operation of a ceiling cassette type air conditioner, drain water generated by the evaporating action of an indoor heat exchanger is stored in a drain pan (drain pan) and drained by a drain pump. Have been. In order to prevent the drain water from overflowing from the drain plate (overflow), a float switch for detecting the amount of drain water stored in the drain plate is provided.

[0004] The float switch is installed in the drain pan, and the fluctuation of the drain water in the drain pan (up and down)
And a switch unit that is activated according to the vertical position of the float unit.

That is, an overflow detection signal is output to the drain pump via a control unit or the like due to an increase in the amount of drain water in the drain dish.

[0006] The drain pump sucks the drain water stored in the drain plate in response to the sent overflow detection signal and discharges the drain water to the outside via a pipe. Then, when the drain water amount in the drain plate is reduced by the drain water discharge processing of the drain pump and reaches a predetermined position, transmission of the signal from the float switch is stopped. As a result, the drain pump stops.

[0007] The above control is repeated according to the rising operation and the descending operation of the float portion of the float switch based on the fluctuation of the level of the drain water (the above-mentioned predetermined position represents the operation start position and the end position of the float portion). Since it is a water surface position, it is hereinafter referred to as an operation surface position).

As a result, since the drain water accumulated in the drain pan does not accumulate beyond a predetermined amount, the drain water does not overflow (overflow) from the drain pan, and the air conditioner (indoor unit) accompanying the overflow is prevented. ) And problems such as dropping of drain water on the indoor floor can be eliminated.

In the above-described ceiling cassette type multi-air conditioner and the like, the drain water discharge piping of each indoor unit installed in a predetermined section is a common drain water discharge piping (common piping). ), And all drain water discharged through each pipe of each indoor unit is discharged outside through a common pipe.

On the other hand, in the ceiling cassette type multi-air conditioner, the refrigerant delivered from the outdoor unit (compressor) during the cooling operation is sent to the indoor heat exchanger via the electronic control valve (PMV) of each indoor unit. The flow of the refrigerant to each indoor unit is controlled by adjusting the opening of the valve unit.

Therefore, for example, when there is an indoor unit whose operation has been stopped and the cooling operation of the multi-air conditioner has been performed for a predetermined time, the refrigerant gradually enters the indoor heat exchanger of the indoor unit whose operation has been stopped. Stays. At this time, since the refrigerant discharged from the outdoor unit contains oil for lubricating the crankshaft of the compressor (lubricating oil, cooling oil), lubrication to the stopped indoor unit during the cooling operation is performed. For the purpose of preventing oil stagnation, an oil recovery control for periodically circulating the refrigerant by opening the valve of the indoor unit whose operation is stopped for a predetermined time is executed.

[0012]

Since the draining process of the drain water in the drain plate is performed only in accordance with the change in the position of the float of the float switch, the drain water in the drain plate is discharged by the float switch of the float switch. It could only be discharged to the operating surface position of the part.

[0013] For this reason, the drain water remaining near the operation surface is evaporated or cooled in response to a change in the surface temperature of the indoor heat exchanger caused by switching of the operation mode or the like. Thus, the evaporation and cooling action of the drain water causes dew condensation inside the indoor unit housing. Then, the dew inside the indoor unit housing may evolve over time and cause water leakage of the indoor unit.

Further, since the drain water in the drain pan is stagnated at the position of the operating surface of the float, the stagnant drain water may cause chattering in the float. As a result, chattering may occur even in the drain pump, and improvement has been desired.

In particular, in a configuration in which drain water discharged from an indoor unit is discharged to the outside through a common pipe, for example, when there is an indoor unit whose operation is stopped, the operation of the indoor unit is stopped. There is a possibility that the drain water discharged from the unit flows backward and flows into the drain plate of the indoor unit that is not operating.

In the event that the above-mentioned backflow occurs, the amount of drain water in the drain plate of the stopped indoor unit is increased, and as a result, the above-described dew condensation phenomenon occurs greatly in the stopped indoor unit, and there is a danger of water leakage. The result is an increase in sex.

Particularly, in the multi-air conditioner, the above-described oil recovery control is performed by circulating the refrigerant to the indoor unit whose operation is stopped.

However, since the indoor heat exchanger of the operation-stopped indoor unit does not perform the heat exchange operation, the indoor heat exchanger is cooled by the sent refrigerant, and the amount of drain water in the drain plate increases and Drain water was cooling.

As a result, an increase in the amount of drain water in the drain plate and a cooling effect of the drain water cause the above-described dew condensation phenomenon inside the housing of the operation-stopped indoor unit, and water leakage occurs in the operation-stopped indoor unit. There was a fear of doing.

The present invention has been made in view of the above-mentioned circumstances, and is intended to discharge the drain water in the drain pan as much as possible regardless of the control of the float switch or the control of the float switch. In the case of an air conditioner, an object of the present invention is to provide a highly reliable air conditioner by preventing the occurrence of dew phenomena particularly in a shutdown indoor unit.

[0021]

According to the air conditioner of the present invention, there is provided an indoor heat exchanger, a drain plate for storing drain water, and a drain water stored in the drain plate. A room equipped with a float switch that detects a water surface position and transmits a control signal, and a drain pump that discharges drain water stored in the drain dish based on the control signal transmitted from the float switch. An air conditioner in which a plurality of air conditioners are disposed in the same section and drain water discharged by a drain pump of each of the plurality of indoor units is discharged to the outside through a common pipe; The drain pumps of at least some of the indoor units are driven in response to the control signals transmitted from the float switches of at least some of the indoor units, and the drains of the at least some of the indoor units are driven. While discharging treated drain water in the tray, and a control means for the drain pump from the control signal transmission stop time when the transmission of the control signal is stopped by driving a predetermined time is performed drain water discharge process.

In particular, when the operation mode is switched while all of the plurality of indoor units are operating in a predetermined operation mode, the drain pumps of all the indoor units are driven for a predetermined time to discharge drain water. Control means for performing processing is provided.

According to the air conditioner of the present invention, in order to achieve the above-mentioned object, an indoor heat exchanger, a drain plate for storing drain water, and a water surface position of the drain water stored in the drain plate are determined. An indoor unit having a float switch for detecting and transmitting a control signal, and a drain pump for discharging drain water stored in the drain dish based on the control signal transmitted from the float switch is provided in the same compartment. A plurality of indoor units connected to the outdoor unit, and a refrigeration cycle is configured between each indoor unit and the outdoor unit. Means for starting the cooling operation of the remaining indoor units while at least one of the indoor units is stopped, and the operation stop chamber according to a lubricating oil recovery control signal sent from the outdoor unit during the cooling operation. Means for controlling the recovery of the lubricating oil retained in the operation-stopped indoor unit by circulating the refrigerant through the unit, and driving the drain pump of the operation-stopped indoor unit for a predetermined time in response to the lubricating oil recovery control signal to thereby discharge the drain water. Control means for performing a discharging process.

In particular, according to the present invention, each of the plurality of indoor units has an indoor fan, and further includes indoor fan driving means for driving the indoor fan for a predetermined time in accordance with the lubricating oil recovery control signal.

According to the present invention, during the cooling operation, the position of the surface of the drain water stored in the drain plate is detected by the float switch, and the control signal is transmitted to drive the drain pump, thereby driving the drain pump. Drain water is discharged.

At this time, the drain pump is driven for a predetermined time by the control means from the time when the water level is detected to be equal to or lower than the predetermined water level, and the drain water discharging process is continuously performed.

That is, the water level of the drain water in the drain plate is controlled by controlling the float switch because the drain pump is driven for a predetermined time from when the float switch detects a predetermined water level or less to discharge the drain water. It is further lowered with respect to the predetermined position concerned.

A plurality of such indoor units are disposed in the same section (for example, behind the ceiling), and drain water discharged by a drain pump of each of the plurality of indoor units is supplied to the outside via a common pipe. To be discharged to

Further, in the present invention, the cooling operation of the remaining indoor units is started in a state where at least one of the plurality of indoor units is stopped, and the recovery control of the lubricating oil sent from the outdoor unit during the cooling operation is performed. In accordance with the signal, the refrigerant is circulated through the operation-stopped indoor unit, and the recovery control of the lubricating oil retained in the operation-stopped indoor unit is performed.

At this time, according to the lubricating oil recovery control signal,
The control means drives the drain pump of the operation-stopped indoor unit for a predetermined time to perform drain water discharge processing.

That is, during the lubricating oil recovery control, the indoor heat exchanger of the stopped indoor unit is cooled by the refrigerant sent from the outdoor unit. Since the drain water is discharged, the amount of drain water in the drain plate can be reduced as much as possible even if the cooling operation of the indoor heat exchanger by the circulating refrigerant occurs.

[0032]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the following embodiments, a description will be given of a multi-air conditioner that is an air conditioner of a ceiling cassette type, in which one outdoor unit is provided with several indoor units.

(First Embodiment) FIG. 1 is a diagram showing a pipe connection relationship of the entire multi-air conditioner according to the present embodiment. As shown in FIG. 1, a multi-air conditioner 1 includes an outdoor unit 2 having a compressor (compressor), an outdoor heat exchanger, and the like.
And a plurality of indoor units 4a1 to 4a3 connected to the outdoor unit 2 disposed in the same section (in the back of the ceiling in the present embodiment) via the first refrigerant circulation pipe 3, and the first refrigerant circulation. Indoor units 4a4 to 4a6 are connected to a branch header 6 connected to a branch pipe 5 branched from the main pipe 3 via a second refrigerant circulation pipe 7, respectively.

Each of the indoor units 4a1 to 4a6 has a drain water discharge pipe 10a1 to 10a6, respectively, and each of the drain water discharge pipes 10a1 to 10a6 has a common drain water discharge pipe (common pipe). Drain water discharged through the respective drain pipes 10a1 to 10a6 is all discharged to the outside through the common pipe 11.

FIG. 2 is a diagram showing the structure of the indoor unit 4a1 in FIG.

In FIG. 2, the indoor unit 4a1 has, for example, a substantially rectangular parallelepiped casing (casing) 15 and is installed along a ceiling surface 16. In the housing 15, an indoor fan 17 and an indoor heat exchanger 18 located on the leeward side of the indoor fan 17 are installed.

A panel 20 is arranged on the ceiling surface 16 along the inner surface of the ceiling surface 16 on the indoor side, and a suction grill 21 is provided on a part of the panel 20. Then, it communicates with the suction grille 21 and the suction port 22 of the indoor fan 17.
The air drawn in from the indoor side as shown by an arrow S1 in the drawing to the indoor heat exchanger 18 through the suction grill 21, the suction port 22, and the indoor fan 17 to the indoor heat exchanger 18 is provided with an arrow S2 in the drawing.
As shown in FIG.

The air that has been heat-exchanged through the indoor heat exchanger 18 is discharged through a discharge port 25 provided in the housing 15 and has a cylindrical flange member 26 as shown by an arrow S3 in the figure.
Is sent to the room via a duct (not shown) connected to the room.

On the other hand, a drain plate 30 for storing drain water generated by the evaporative cooling operation of the indoor heat exchanger 18 at the time of cooling, and an amount of drain water stored in the drain plate 30 are provided in the housing 15. Switch 31, a drain pump 32 capable of sucking (pumping) drain water in a drain plate 30, a float switch 31, a drain pump 32, and a fan motor 17 for driving the indoor fan 17.
a, and a control unit 33 such as a microprocessor electrically connected to the valve unit 19 and the like.

The control unit 33 includes the float switch 31
The other components of the indoor unit 4a1 including the operation control of the drain pump 32 in response to a control signal from the controller or a control signal (for example, an operation mode switching signal or an operation start / stop signal) from a remote control device (remote controller) or the like. It has a function of performing control (rotation control of the indoor fan 17 based on the control signal c1, control of opening and closing of the valve section 19 based on the control signal c2, etc.), control of the outdoor unit 2, and the like.

The drain pump 32 includes a pump body 35 having a suction port 35a located in the drain plate 30, and a drive unit (motor) 36 for driving the pump body 35 to perform a drain water suction operation. ing. Pump body 35
A drain pipe 37 for discharging drain water sucked up by the pump body 35 is provided on a side surface of the pump body 35. The drain pipe 37 extends once upward as shown by a broken line in the drawing and is then pulled out substantially horizontally, and penetrates the side wall of the housing 15 and is connected to the drain water discharge port 38. The drain water outlet 38 is connected to the drain water discharge pipe 1 shown in FIG.
The drain pipe 10a1 is connected to a common pipe 11.

The position of the suction port 35 a of the drain pump 32 (that is, the position where the drain water in the drain plate 30 is sucked) is determined as a position Pa close to the bottom surface of the drain plate 30. The position P in the drain pan 30
Va is the amount of drain water accumulated up to a.

The float switch 31 is installed in the drain plate 30 so as to hang down in the depth direction. That is, when the water surface position of the drain water in the drain plate 30 fluctuates (ascends and descends) in a range exceeding a predetermined position, the float switch 31 ascends and descends according to the fluctuation (ascends and descends). It has a float unit 31a and a switch unit 31b that controls the output of the overflow detection signal in accordance with the fluctuation of the float unit 31a.

In the drain plate 30, a float 31
The amount of drain water accumulated up to the operating surface position P1 of a is represented by V
Then, this V is about 10 times the amount of drain water of the drain water stored up to the above-mentioned position Pa.

The control unit 33 controls the motor 36 based on the output and stoppage of the overflow detection signal from the switch unit 31b of the float switch 31, and controls the suction operation of the drain pump 32 and the control of the indoor unit 4a1 and the outdoor unit 2. Is to be executed.

Although the configuration of the indoor unit 4a1 has been described with reference to FIG. 2, all the other indoor units 4a2 to 4a6 have the same configuration, and a description thereof will be omitted.

Next, the overall operation of the present configuration will be described focusing on the control operation of the control unit 33.

In the multi-air conditioner 1, for example, all the indoor units 4a1 to 4a6 are operated (cooling operation) based on a predetermined operation mode (for example, cooling operation mode) (FIG. 3; step S1).

The drain water generated by the evaporative cooling operation of the indoor heat exchanger 18 is stored in the drain plate 30.

As the cooling operation is continued, the height (position) of the water surface of the drain water in the drain plate 30 rises, and with the rise, the float portion 31a of the float switch 31
When the lower surface of the float switch 31 exceeds the operating surface position P1, the switch unit 31b of the float switch 31 sends the overflow detection signal to the control unit 33.
(Step S2).

After transmitting a low-speed cooling operation command to the outdoor unit 2 in response to the sent overflow detection signal,
The drain pump 32 is driven. As a result, the drain pump 32 starts the drain water suction operation, and the drain plate 30
The drain water inside is discharged through the discharge pipe 37 and the like (step S3).

The drain water level of the drain plate 30 gradually decreases due to the drain water discharge process of the drain pump 32, and the float part 31a of the float switch 31 descends with the decrease of the water level. When the lower surface of the float 31a reaches the operating surface position P1 (see FIG. 4), the switch 31b of the float switch 32 stops transmitting the overflow detection signal to the controller 33 (step S4).

At this time, the control unit 33 controls the switch unit 31
Even after the transmission of the overflow detection signal from b is stopped, the motor 36 is controlled to continue driving the pump body 35 for a predetermined time. As a result, the drain water in the drain plate 30 is further discharged through the discharge pipe 37 or the like (Step S).
5).

After a predetermined time has elapsed, for example, when the level of the drain water in the drain plate 30 reaches Pa (see FIG. 5), the control unit 33 controls the motor 36 to The driving, that is, the drain water discharge process is stopped, and the process is terminated (step S6).

As a result, as shown in FIG.
Drain water volume Va stored (retained) in 0
Is the water holding amount V controlled only by the conventional float switch 31.
Of the drain water in the drain plate 30 can be reduced as much as possible.

That is, the drain water in the drain plate 30 is
Since the float switch 31 does not stagnate at the operating surface position of the float portion 31a but exists near the bottom surface of the drain plate 30, it can be used for evaporation and cooling of drain water which has stagnated at the conventional operating surface position of the float portion. Occurrence of the resulting dew condensation phenomenon can be eliminated or greatly suppressed, and water leakage of the indoor unit can be prevented. Further, it is possible to prevent chattering of the float part and the drain pump caused by the drain water that has stagnated at the operating surface position of the float part of the float switch.

Further, since the amount of drain water in the drain plate 30 is reduced, it is possible to reduce the occurrence of corrosion and abnormal odor of the drain plate when the drain water is retained in the drain plate 30 for a long period of time.

In this embodiment, all the indoor units 4a
Although an example in which 1 to 4a6 are operated (cooling operation) based on the cooling operation mode has been described, the present invention is not limited to this, and can be applied to various mode operations such as a dry mode and a heating mode. is there. That is, the control of the float switch 31 and the control of the drain pump 32 are performed regardless of the operation mode.

In this embodiment, all the indoor units 4a
The drain water discharge processing when the cooling air is operated in the cooling operation mode is described above. However, as described above, in the multi-air conditioner, in the indoor unit whose operation is stopped, for example, the back flow of the drain water through the common pipe, etc. Drain water increase due to →
The problem of the occurrence of dew condensation occurs.

However, by applying the drain water discharge processing of the present embodiment, it is possible to prevent an increase in the amount of drain water and the occurrence of dew condensation in the indoor unit during operation stoppage.

That is, among the indoor units 4a1 to 4a6, for example, the indoor unit 4a1 has stopped operating, and the indoor heat exchanger associated with the reverse flow of the drain water discharged from the operating indoor unit and the oil recovery control described above. Even if the amount of drain water in the drain plate 30 of the shutdown indoor unit 4a1 increases due to the cooling action of the above, if the lower surface of the float portion 31a exceeds the operating surface position P1 with the increase in the amount of drain water, the above-described step is performed. S2
Since the amount of drain water in the drain plate 30 of the operation-stopped indoor unit 4a1 is greatly reduced as shown in FIG. 5 by the processing of step S6, the occurrence of the dew condensation phenomenon accompanying the increase in the drain water of the operation-stopped indoor unit 4a1 is prevented. And the operation-stopped indoor unit 4
The occurrence of chattering in a1 can be prevented.

In this embodiment, the float 3
1b in response to the stoppage of the overflow detection signal
2 is operated for a predetermined period of time to perform drain water discharge processing. In addition to this control, other drain water discharge control may be executed.

That is, the fact that the stagnation at the operating surface position P1 of the float portion 31a of the drain water is a significant problem is, for example, a change in the operation mode of a certain indoor unit (cooling → heating, etc.) or a change in operation / stop. Is caused by a change in the surface temperature of the indoor heat exchanger of the indoor unit.

Therefore, drain water discharge processing may be performed when the above-described control operation that causes a change in the surface temperature of the indoor heat exchanger is performed.

For example, in the multi-air conditioner 1, (1) a predetermined operation mode (for example, a cooling operation mode) of all the indoor units 4a1 to 4a6 is set based on an operation of a remote control device or the like of each of the indoor units 4a1 to 4a6. (2) when the entire indoor unit including all the indoor units 4a1 to 4a6 is switched from operation to stop, and (3) when the operation mode is switched to another operation mode (for example, a heating operation mode (hot gas blow or the like)). When the entire indoor unit including all the indoor units 4a1 to 4a6 is switched from the operation stop to the operation state, the control unit 33 of each of the indoor units 4a1 to 4a6 performs (1)
The respective motors 36 are controlled in accordance with the switching signals of (3) to drive the respective pump bodies 35 for a predetermined time. As a result,
Drain water in each drain plate 30 of each of the indoor units 4a1 to 4a6 is discharged through each discharge pipe 37 or the like (FIG. 6; step S10).

After a lapse of a predetermined time, for example, when the level of the drain water in the drain plate 30 reaches Pa shown in FIG. 7, the control unit 3 of each of the indoor units 4a1 to 4a6 is controlled.
3 controls each motor 36 to stop the driving of each pump body 35, that is, the drain water discharge process, and ends the process (step S11).

As a result, even if the surface temperature of each of the indoor heat exchangers 18 of each of the indoor units 4a1 to 4a6 changes in accordance with the switching of the operation mode and the like, each of the drain plates 30 of each of the indoor units 4a1 to 4a6 is changed. Since the drain water in the inside is greatly reduced as compared with the conventional case, even if the drain water is evaporated and cooled, no dew condensation phenomenon occurs, and each indoor unit 4a1
4a6 can be prevented from leaking.

Note that, of all the indoor units 4a1 to 4a6,
When the operation mode switching or the operation / stop state switching of the specific indoor unit is performed, the drain pump 35 of the specific indoor unit may be continuously operated for a predetermined time.

(Second Embodiment) Next, a second embodiment of the present invention will be described. The multi-air conditioner 1 according to the present embodiment has a feature in processing when performing the above-described lubricating oil recovery control, and the configuration itself is substantially the same as that of the first embodiment (see FIGS. 1 and 2). Therefore, the description is omitted.

In the multi-type air conditioner 1 of the present embodiment, for example, the indoor unit whose operation is stopped (for example, the indoor unit 4
If a1) exists, the other indoor units 4a2 to 4a6 are operated for cooling (FIG. 7; step S20).

During the cooling operation, the lubricating oil recovery control is periodically performed at a required timing in order to prevent the lubricating oil from remaining in the operation-stopped indoor unit 4a1.

That is, the outdoor unit 2 is a
A lubricating oil recovery signal (pulse signal) having a pulse width until a predetermined amount of lubricating oil is recovered by the compressor 2a of the outdoor unit 2 is transmitted to the control unit 33 (step S1).
21; see the time chart of FIG. 8). The control unit 33 receives the transmitted lubricating oil recovery control signal (step S2).
2).

In response to the transmitted lubricating oil recovery control signal, the control unit 33 transmits the control signal c2 to the valve unit for opening and closing the corresponding indoor heat exchanger to open the valve unit by a predetermined amount, and The signal c1 is transmitted to the fan motor 17a to drive the fan motor 17a to drive the indoor fan 17 at a very low speed (UL mode) (step S23; see FIG. 8). As a result, the refrigerant circulates and the indoor heat exchanger 1
The refrigerant and the lubricating oil retained in the inside 8 are recovered to the outdoor unit 2 (compressor) side.

Further, simultaneously with the opening control of the valve section and the operation control of the indoor fan 17, the control section 33 controls the motor 36 of the drain pump 32 by controlling the motor 36 of the drain pump 32 in accordance with the transmitted lubricating oil recovery control signal. 35 is driven. As a result, the drain pump 32 starts the drain water suction operation, and the drain water in the drain plate 30 is discharged through the discharge pipe 37 or the like (step S24; see FIG. 8).

At this time, the control unit 33 determines whether or not the transmission signal of the lubricating oil recovery signal from the outdoor unit 2 is stopped (cancellation of transmission) (step S25). (The result of the determination in step S25 is NO), the processes in step S23 and step S24 are continuously executed.

If the transmission of the lubricating oil recovery signal is canceled (YES in step S25), the controller 33 closes the valve simultaneously with the release of the transmission of the lubricating oil recovery signal (step S26). ; See FIG. 8), and after a lapse of a predetermined time from the release of the transmission of the lubricating oil recovery signal (after a lapse of a delay time until all the refrigerant sent to the indoor heat exchanger 18 returns to the compressor 2a), the fan motor 17a is controlled Then, the operation of the indoor fan motor 17 is stopped, and the driving of the pump body 35 is stopped by controlling the motor 36 of the drain pump 32, thereby completing the lubricating oil recovery processing (step S27;
8), normal cooling operation (indoor units 4a2 to 4a6)
Return to

That is, also in this embodiment, the indoor heat exchanger 18 of the operation-stopped indoor unit 4a1 during the lubricating oil recovery control is operated.
Is cooled by the refrigerant sent from the outdoor unit 2, and during the lubricating oil recovery control and until all the refrigerant is sent out from the indoor heat exchanger 18 (delay time), the drain pump 32 Since the drain water in the plate 30 is discharged, even if the cooling operation of the indoor heat exchanger 18 by the circulating refrigerant occurs, the amount of drain water in the drain plate can be reduced as much as possible. The influence on the drain water in the inside can be suppressed to a necessary minimum. As a result, the cooling effect of the indoor heat exchanger 18 and the occurrence of dew condensation caused by drain water can be eliminated or greatly suppressed, and water leakage from the operation-stop indoor unit 4a1 can be prevented.

In this embodiment, the control unit 33 controls (closes and stops) the valve unit, the indoor fan 17 and the motor 36 in response to the release of the transmission of the lubricating oil recovery control signal. As one type of release of the lubrication oil recovery control signal, even when a cooling operation start signal is transmitted from a remote control device (not shown) or the like, the control of the valve unit, the indoor fan 17, and the motor 36 (closing operation, stop control) ). In this case, the control of the indoor fan 17 and the motor 36 is executed immediately after the elapse of the delay time, not according to the cooling operation start signal.

In this embodiment, the control unit 33 drives the indoor fan 17 at a very low speed (UL mode) in response to the release of the transmission of the lubricating oil recovery control signal. The cooling effect of the indoor heat exchanger by the circulating refrigerant can be reduced by slightly performing the heat exchange operation of the indoor heat exchanger while suppressing the cool air blowing.

Further, the drain pump driving process according to the lubricating oil recovery control of the present embodiment can be used in combination with the drain pump driving process of the first embodiment. Machine can be provided.

In the first and second embodiments, each indoor unit of the ceiling cassette type multi-air conditioner is configured as shown in FIG. 2, but the present invention is not limited to this. For example, install the motor of the indoor fan on the ceiling,
The indoor unit may be provided with a centrifugal fan at a lower portion that sucks room air from the lower surface and blows the air in the peripheral direction.

In this configuration, a bell mouth is installed on the lower surface (suction port) of the centrifugal fan via a mounting plate to increase the suction area. However, a metal bell for mounting the bell mouth is provided. A heat insulating material may be attached to the mouse mounting plate. With this configuration, it is possible to prevent the surface of the bell mouth mounting plate at the suction port portion of the centrifugal fan from being exposed due to the cooling of the indoor heat exchanger of the operation stopped indoor unit.

Although the first and second embodiments have described the ceiling cassette type multi air conditioner, the multi air conditioner may be of a type other than the ceiling cassette type.

In particular, in the first embodiment, the present invention is applicable not only to a multi-air conditioner but also to a normal air conditioner. In the second embodiment, a plurality of air conditioners can be installed in the same section shown in FIG. Although the configuration in which the indoor units are arranged as a parallel circuit has been described, as an advanced configuration thereof, a configuration in which a plurality of indoor units arranged as a parallel circuit and controls the capacity of each heat exchanger, The present invention is also applicable to a configuration in which a plurality of heat exchangers are switched and used.

[0085]

As described above, according to the air conditioner of the present invention, since the drain water in the drain plate does not stay at the operating surface position of the float switch, the drain water in the drain plate is kept. The amount of water can be reduced as much as possible.

Therefore, it is possible to substantially eliminate the occurrence of the dew condensation phenomenon caused by the evaporation and cooling of the drain water, and it is possible to prevent the water leak from the indoor unit. Further, since chattering caused by drain water that has been stagnating at the operation surface position of the float switch can be prevented, it is possible to provide an air conditioner with greatly improved reliability and usability. it can.

Further, according to the present invention, even if the lubricating oil recovery control is executed in the multi-type air conditioner, the drain water in the drain plate is discharged by the drain pump during the lubricating oil recovery control. Therefore, even if the circulating refrigerant causes a cooling effect of the indoor heat exchanger of the operation stopped indoor unit, the amount of drain water in the drain plate can be reduced as much as possible. Therefore, the influence on the drain water in the drain plate due to the execution of the lubricating oil recovery control can be suppressed to a necessary minimum, and the occurrence of the dew condensation phenomenon can be substantially eliminated to prevent the leakage of the operation stop indoor unit. it can. As a result, it is possible to provide an air conditioner having significantly improved reliability and usability.

[Brief description of the drawings]

FIG. 1 is a diagram showing a connection configuration of a ceiling cassette type multi-air conditioner according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a schematic configuration of the indoor unit in FIG.

FIG. 3 is a schematic flowchart illustrating an example of processing of an indoor unit including a control unit according to the first embodiment.

FIG. 4 is an enlarged view of a main part showing the operation of the float switch, the drain pump, the level of drain water, and the like in FIG. 2;

FIG. 5 is an enlarged view of a main part showing the operation of the float switch in FIG. 2, the drain pump, the level of drain water, and the like.

FIG. 6 is a schematic flowchart illustrating an example of processing of a control unit according to a modified example of the first embodiment.

FIG. 7 is a schematic flowchart illustrating an example of processing of an indoor unit and an outdoor unit including a control unit according to the second embodiment.

FIG. 8 is a time chart showing control signals and operation timings associated with lubricating oil recovery control.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multi air conditioner 2 Outdoor unit 3 First refrigerant circulation pipe 4a1-4a6 Indoor unit 5 Branch pipe 6 Branch header 7 Second refrigerant circulation pipe 10a1-10a6 Drain water discharge pipe 11 Common pipe 15 Housing 17 Indoor Fan 17a Fan Motor 18 Indoor Heat Exchanger 30 Drain Plate 31 Float Switch 31a Float 31b Switch 32 Drain Pump 35 Pump Body 36 Motor 37 Discharge Pipe

Claims (7)

[Claims] An indoor heat exchanger, a drain plate for storing drain water, a float switch for detecting a water surface position of the drain water stored in the drain plate and transmitting a control signal,
A plurality of indoor units each having a drain pump for discharging drain water stored in the drain plate based on a control signal transmitted from the float switch are provided in the same section, and the plurality of indoor units are provided. In an air conditioner configured to discharge drain water discharged by a drain pump of each unit to the outside via a common pipe, the air conditioner is transmitted from a float switch of at least a part of the plurality of indoor units. The drain pump of at least a part of the indoor unit is driven in response to the control signal to discharge drain water in a drain plate of the indoor unit, and when the transmission of the control signal is stopped, the control signal is transmitted. An air conditioner comprising control means for driving the drain pump for a predetermined time from a stop to perform drain water discharge processing. 2. When the operation mode is switched while all of the plurality of indoor units are operating in a predetermined operation mode, the drain pumps of all the indoor units are driven for a predetermined time to discharge drain water. The air conditioner according to claim 1, further comprising control means for performing processing. 3. The air conditioner according to claim 1, further comprising control means for driving drain pumps of all the indoor units for a predetermined time to perform drain water discharge processing when all of the plurality of indoor units are stopped. Machine. 4. When at least one of the plurality of indoor units is performing a cooling operation and the indoor unit performing the cooling operation is stopped, a drain pump of the indoor unit that has stopped the cooling operation is determined. 2. The air conditioner according to claim 1, further comprising control means for performing drain water discharge processing by driving for a time. 5. When the operation of all the indoor units is started from the state in which the operation of all of the plurality of indoor units is stopped, the drain pumps of all the indoor units are driven for a predetermined time to perform a drain water discharge process. The air conditioner according to claim 1, further comprising control means. 6. An indoor heat exchanger, a drain plate for storing drain water, a float switch for detecting a water surface position of the drain water stored in the drain plate and transmitting a control signal,
A plurality of indoor units each including a drain pump for discharging drain water stored in the drain dish based on a control signal transmitted from the float switch are arranged in the same section, and the plurality of indoor units are provided. In a multi-type air conditioner in which a refrigerating cycle is configured between each indoor unit and the outdoor unit by connecting the unit to an outdoor unit, at least one of the plurality of indoor units remains in a stopped state. Means for initiating the cooling operation of the indoor unit, and refrigerant circulating in the operation-stopped indoor unit in response to the lubricating oil recovery control signal sent from the outdoor unit during the cooling operation, and accumulated in the operation-stopped indoor unit. Means for performing lubricating oil recovery control, and control means for performing a drain water discharge process by driving a drain pump of the operation-stopped indoor unit for a predetermined time in accordance with the lubricating oil recovery control signal. An air conditioner characterized by the following. 7. The air conditioner according to claim 6, wherein each of the plurality of indoor units has an indoor fan and an indoor fan drive unit that drives the indoor fan for a predetermined time in accordance with the lubricating oil recovery control signal. .