JPH0325079Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention targets air conditioners such as ceiling-mounted air conditioners that are used by being embedded in the ceiling or suspended from the ceiling. This invention relates to a control system for a drain pump for discharging drain water.

(Prior Art) In this type of ceiling-mounted air conditioner, drain water is discharged through a drain channel provided in the ceiling. Therefore, for example, as disclosed in Japanese Utility Model Application Publication No. 51-72954, there is a system in which drain water is pumped up to a predetermined height in order to obtain an appropriate drain gradient in the ceiling. In these air conditioners, during cooling operation or dehumidification operation, for example, thermo-control of the indoor temperature, protection against overload operation of the compressor, prevention of freezing of the indoor heat exchanger when the indoor temperature drops, drain water from the drain pan, etc. When the compressor is stopped to prevent overflow, etc., the drain pump is stopped at a predetermined time, for example, 5 minutes after the compressor is stopped, in order to treat the drain water that has accumulated in the drain pan even after the compressor is stopped. It may be controlled to delay by a certain amount of time.

(Problem to be solved by the invention) However, when the compressor is stopped to prevent the heat exchanger from freezing, the moisture that had been frozen in the heat exchanger melts as the compressor stops. Since the drain water drips into the drain pan, simply delaying the stoppage of the drain pump for a certain period of time as described above is insufficient to ensure drain water is discharged, and there is a risk that the drain water will overflow from the drain pan and leak into the room. .

Therefore, the purpose of this invention is to monitor the subsequent thawing state of the heat exchanger when the compressor is stopped to prevent the heat exchanger from freezing during cooling operation as described above. By adjusting the stop timing of the drain pump to correspond to that period, it is possible to reliably drain the drain water that accumulates in the drain pan as the heat exchanger thaws after the compressor is stopped, and to prevent drain water from the air conditioner. The purpose is to prevent water leakage accidents.

(Means for solving the problem) In order to achieve the above purpose, the solution of the present invention is as follows:
As shown in FIG. 1, a drain pan 1 is installed below the heat exchanger 7 that exchanges heat between the refrigerant from the compressor 2 and the air.
A drain pump 1 driven by a motor 14 pumps drain water stored in the drain pan 13.
5, the air conditioner is configured to be pushed up to a predetermined height position and discharged, and is provided with freeze detection means 23 for detecting a frozen state due to the heat exchange action of the heat exchanger 7. Then, the output signal of the freezing detection means 23 is inputted, and the heat exchanger 7 is
When the compressor 2 is frozen, the compressor 2 is stopped, and after the compressor 2 is stopped, the drain pump 15 is continued until the frozen state of the heat exchanger 7 detected by the detection means 23 is released. The configuration includes a control circuit 22 that controls the motor 14 so as to operate it.

(Function) With this configuration, in the present invention, when moisture in the air is condensed in the heat exchanger 7 with the operation of the compressor 2 during cooling operation or dehumidification operation of the air conditioner, the condensed water is The water drips from the heat exchanger 7 and becomes drain water, which collects in the drain pan 13, and then drains into the drain pan 1.
3 is pushed up to a predetermined height by the drain pump 15 and discharged. In this state, when the condensed water in the heat exchanger 7 freezes due to a drop in indoor temperature, the frozen state is detected by the freeze detection means 2.
3, a detection signal is output from the detection means 23, and the control circuit 22 receives this detection signal.
First, the compressor 2 is stopped in order to thaw the heat exchanger 7. Next, after the compressor 2 is stopped, the detecting means 23 monitors whether or not the heat exchanger 7 is frozen, and when the compressor 2 is stopped, the heat exchanger 7 is released from the frozen state, and freezing is detected. When the output of the detection signal from the means 23 stops, the control circuit 22 stops the operation of the drain pump 15. As a result, even if water that is thawed and thawed by the stoppage of the compressor 2 drips from the heat exchanger 7 and accumulates in the drain pan 13, the water is removed from the drain pump 1, which continues to operate.
5, the drain water is quickly drained, and the drain water does not overflow from the drain pan 13.

(Example) Hereinafter, an example in which the present invention is applied to a ceiling-embedded air conditioner will be described.

In Figure 1, the air conditioner is outdoor unit 1.
and an indoor unit 5. The outdoor unit 1 includes a compressor 2, an outdoor heat exchanger 3, and an expansion valve 4.
On the other hand, the indoor unit 5 is equipped with an indoor heat exchanger with a U-shaped cross section, which exchanges heat with indoor air for the refrigerant supplied from the compressor 2, in a case 6 fitted into an opening in the ceiling C. 7 and a fan 8 for ventilation, and the case 6 has an inlet 9 and an outlet 10 opened toward the indoor side. The heat exchanger 7 is the compressor 2 of the outdoor unit 1.
are connected to each other via a gas passage 11 and a liquid passage 12. Therefore, while the indoor air sucked by the fan 8 passes through the heat exchanger 7, heat is removed by the heat exchanger 7, and the air is discharged from the outlet 10. Note that 24 is a chamber for effectively flowing the air sent out from the fan 8 to the heat exchanger 7.

A drain pan 13 is provided below the heat exchanger 7 to receive water droplets condensed on the heat exchanger 7 during cooling or dehumidification operation. A motor 14 is fixed to a fixed wall inside the case 6 facing the drain pan 13, and rotates a drain pump 15 installed in the drain 13 with this motor 14. The drain pump 15 includes a pump casing 18 having a suction port 16 at the center of the lower surface and a discharge port 17 at the outer periphery, and an impeller (not shown) housed in the pump casing 18. In order to obtain an appropriate drain pan slope in the ceiling, the discharge port 1 is
A discharge passage 19 connected to the drain pump 7 is raised to a predetermined height and exposed to the outside of the case 6, and a drain hose 21 is connected to this discharge passage 19 via a connector 20. Drain pan 1
The drain water in the pump 3 is sucked in in a state mixed with air, and is pushed up to a predetermined height position through a discharge port 17 opening laterally through a discharge passage 19 and then discharged.

The operation of the motor 14 that drives the drain pump 15 is controlled by a control circuit 22 together with the compressor 2, as shown in FIG. The control circuit 22
includes a thermo signal to adjust the indoor temperature,
a pressure signal for overload operation protection of the compressor 2;
A water level signal corresponding to the level of drain water in the drain pan 13 is inputted, and an output signal from the freeze detection means 23 for detecting the frozen state of the heat exchanger 7 is also inputted. Freeze detection means 2
3 is equipped with a temperature sensor such as a thermistor that detects the temperature of the heat exchanger 7, and for example, when the temperature of the heat exchanger 7 detected by this temperature sensor is 6 minutes after the start of operation of the compressor 2. If the temperature is -7.3°C or lower, it is determined that the heat exchanger 7 is in a frozen state and a detection signal is output, and if the temperature becomes 7.7°C or higher, it is determined that it is in an unfrozen state and the output of the detection signal is stopped. Based on the output signal of the freeze detection means 23, the control circuit 22 stops the compressor 2 when the heat exchanger 7 freezes, and after the compressor 2 is stopped, the freeze detection means 23 The motor 14 is controlled to operate the drain pump 15 until the frozen state of the heat exchanger 7 detected by the above is released.

Therefore, in the above embodiment, when the air conditioner is in cooling operation or dehumidification operation, as shown in _FIG . , it is determined whether or not to stop the compressor 2 in order to prevent an abnormal rise in the water level of drain water and to prevent the heat exchanger 7 from freezing. If this determination is NO, the process advances to step S2 to stop the compressor ₂ .
is activated, and at the same time, the drain pump 15 is maintained in an activated state in step _S3 . With the operation of the compressor 2, the refrigerant from the compressor 2 is transferred to the indoor unit 5.
At the same time, the moisture in the indoor air that is condensed in the heat exchanger 7 drips and becomes drain water and accumulates in the drain pan 13, and the drain water in the drain pan 13 is The water is discharged to the outside by the operation of the drain pump 15.

On the other hand, when the judgment is YES, the step
Proceed to S ₄ , compressor 2 is stopped, and at the same time,
In step _S5 , counting of the remaining timer for the drain pump 15, which is set to, for example, 5 minutes, is started, and then in step _S6 it is determined whether the remaining timer has counted up. When this determination is NO, the process proceeds to step _S7 and the drain pump 15 is continuously maintained in the operating state. On the other hand, if the determination is YES, that is, a predetermined period of time (5 minutes) has elapsed since the compressor 2 stopped operating, the process proceeds to step _S8 , where it is determined whether or not there is an output signal from the freeze detection means 23, and the determination is that there is an output signal. of
If YES, the process advances to step _S9 to check whether the freeze prevention function for the heat exchanger 7 has been canceled, that is, the temperature of the heat exchanger 7 detected by the temperature sensor of the freeze detection means 23 is, for example, 7.7°C or higher. It is determined whether or not it has increased, and this determination is NO.
When this happens, the process proceeds to step _S7 , where the drain pump 15 continues to operate. On the other hand, if the determination is YES, the process advances to step _S10 and the operation of the drain pump 15 is stopped. Further, even when the determination at step ₇₈ is NO, indicating a normal state, the process proceeds to step _S10 , where the drain pump 15 is stopped.

Through the above-described control, when the frozen state of the heat exchanger 7 of the indoor unit 5 is determined, the operation of the drain pump 15 is continued until the frozen state is released, so that when the heat exchanger 7 is released from freezing, the operation of the drain pump 15 is continued. Even if condensed water drips from the heat exchanger 7 and accumulates in the drain pan 13, it is quickly discharged from the drain pan 13 by the operating drain pump 15, and the drain water is removed from the drain pan 13. Overflow does not occur, so water leakage from the indoor unit 5 can be reliably prevented.

Although the embodiment shown in FIG. 2 above shows a refrigerant circuit exclusively for cooling, an air heater (not shown) may be operated during dehumidification operation.
It goes without saying that a heat pump type cooling/heating cycle may also be used using a four-way switching valve.

(Effects of the invention) As described above, according to the invention, in an air conditioner in which the drain water that drips from the heat exchanger of the air conditioner and accumulates in the drain pan is discharged by the drain pump, the heat exchanger freezes. At the same time, the compressor is stopped to release the frozen state, and the drain pump continues to operate until the frozen state is removed. Dripping water can be discharged from the drain pan without overflowing, thereby reliably preventing drain water leakage accidents in air conditioners and improving safety.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a diagram showing the overall configuration of an air conditioner, FIG. 2 is a block diagram of the control system, and FIG. 3 is an explanatory diagram showing the order of control operations. 2...Compressor, 7...Indoor heat exchanger, 13...
...Drain pan, 14...Motor, 15...Drain pump, 22...Control circuit, 23...Freeze detection means.

Claims (1)

[Scope of utility model registration request] A heat exchanger 7 that exchanges heat between the refrigerant from the compressor 2 and air, a drain pan 13 disposed below the heat exchanger 7, and a drain pan 13 that pushes up drain water stored in the drain pan 13 to a predetermined height. An air conditioner comprising a drain pump 15 for discharging water and a motor 14 for driving the drain pump 15 includes a freeze detection means 23 for detecting a frozen state of the heat exchanger 7, and a freeze detection means 23 for detecting a frozen state of the heat exchanger 7. An output signal is input to stop the compressor 2 when the heat exchanger 7 is frozen, and the drain pump 15 is operated after the compressor 2 is stopped until the heat exchanger 7 is released from the frozen state. An air conditioner characterized by being provided with a control circuit 22 for controlling the motor 14 so as to continuously operate the motor 14.