JP2500520B2 - Refrigerator protection device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating device protection device, and more particularly to a device for preventing a device such as a compressor of a refrigerating device from being damaged due to a high or low pressure abnormality.

[0002]

2. Description of the Related Art Conventionally, for example, actual fairness 2-5315
As disclosed in Japanese Patent Publication, a compressor, a condenser, a pressure reducing mechanism,
As a protection device for a refrigeration system equipped with a refrigerant circuit connected to an evaporator, etc., an automatic reset type high voltage switch for protection that outputs a stop signal when the upper limit value after high pressure is exceeded is placed, and the high voltage switch is set within a certain time. By stopping the refrigeration system abnormally when a stop signal is output more than the set number of times from, the failure of equipment such as the compressor is prevented, and the transient high pressure abnormality and the original high pressure abnormality due to some cause It is a well-known technique to distinguish between the two and prevent the occurrence of unnecessary abnormal stop.

[0003]

However, in order to protect the equipment of the refrigeration system, the equipment of the refrigeration system, for example, the compressor, may have an excessive rise in the discharge pipe temperature or run out of oil even when the low pressure is excessively lowered. It is necessary to protect not only the high-pressure side pressure but also the low-pressure side abnormality. In that case, if the above-mentioned conventional one is applied as it is, it is necessary to individually provide a protection circuit for each high-voltage switch and low-voltage switch, and to individually control the circuit, which complicates the circuit configuration and control.
This leads to an increase in cost.

On the other hand, it is empirically known that the pressure on the low pressure side is not excessively lowered under the condition that the pressure on the high pressure side is excessively increased, and the stop signals from the high pressure switch and the low pressure switch are unified. It may be possible to process the However, the abnormalities in the high-pressure side pressure and the low-pressure side pressure do not always occur at the same time interval because their causes are different, so unlike the conventional ones, the abnormal signal does not come a predetermined number of times within a certain period of time. Sometimes, if the integrated value of the stop signal is reset, a problem may occur in performing unified protection control.

The present invention has been made in view of the above point, and simplifies the control by resetting the integrated value of the stop signal at the time when it is determined that the abnormal state is exited from the change in the operating state. It is an object of the present invention to reliably avoid an unnecessary abnormal stop due to a temporary high / low pressure abnormality.

[0006]

In order to achieve the above object, the solution means of the present invention is, as shown in FIG. 1, a compressor (1), a condenser (3 or 6), a pressure reducing mechanism (5) and It is premised on a refrigerating apparatus provided with a refrigerant circuit (9) formed by sequentially connecting evaporators (6 or 3).

As a protection device for the refrigeration system, a first signal output means (HPS) for outputting a stop signal when the high-pressure side pressure becomes higher than the upper limit value, and a stop signal when the low-pressure side pressure becomes lower than the lower limit value. When the stop signal is received from the second signal output means (LPS) and each of the signal output means (HPS) and (LPS), the compressor (1) is controlled to be stopped for a predetermined time and then restarted. Return processing means (51), counting means (33) that collectively integrates the number of times the stop signal is output by both the signal output means (HPS), (LPS), and the stop integrated by the counting means (33) Abnormality processing means (52) for forcibly stopping the control of the return processing means (51) and abnormally stopping the operation of each device of the refrigeration system when the integrated value of the signals reaches or exceeds the set value. ) And the difference in temperature between the room temperature and the room setting temperature A thermo signal output means (53) for outputting a thermo off signal based on the above, and the counting means (when the thermo off signal from the thermo signal output means (53) is received or when the refrigeration system is abnormally stopped. 33) and a resetting means (54) for resetting the integrated value.

[0008]

In the present invention, the high-pressure side pressure in the refrigerant circuit (9) excessively rises or the low-pressure side pressure falls excessively during the operation of the refrigeration system, so that the first signal output means (HPS) is provided. Alternatively, when the stop signal is output from the second signal output means (LPS), the stop signal is integrated by the counting means (33). Until the integrated value reaches the set value or more, the return processing means (51) performs the return processing of stopping the compressor (1) for a predetermined time and then starting it, while the integrated value of the stop signal. When the value reaches the set value, the abnormality processing means (52)
As a result, an abnormal process of stopping each device of the refrigeration system is performed. Therefore, the failure of the compressor (1) or the like due to some abnormality of the device is prevented, and a transient excessive increase in the high-pressure side pressure that occurs at the time of starting the heating operation under high outside air conditions or cooling under low outside air conditions. It is possible to prevent a problem in which a transient excessive decrease in the pressure on the low-pressure side that occurs at the start of operation is determined to be an abnormality of the apparatus itself and is abnormally processed.

In this case, when the operating state of the device changes and the thermo signal output means (53) outputs the thermo-off signal from the indoor side, the stop signal accumulated by the counting means (33) is output. Since the integrated value is reset, the stop signal due to a transient abnormality is accumulated for a long time, so that no abnormality processing is performed, and the time interval at which the high-pressure side abnormality occurs and the time at which the low-pressure side abnormality occurs Even under conditions where the intervals do not necessarily match, uniform protection control from high-low pressure abnormalities is performed without causing problems.

Therefore, the circuit structure and control contents for high and low pressure protection are simplified without causing deterioration of the refrigerating effect and deterioration of reliability due to unnecessary abnormal stop of the device due to transient abnormality of refrigerant pressure. Will be done.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.

FIG. 2 shows a refrigerant piping system of an air conditioner to which the present invention is applied. (1) is a compressor, (2) is a solid line in the drawing during cooling operation, and a broken line in the drawing is in heating operation. A four-way switching valve to be replaced, (3) an outdoor heat exchanger that functions as a condenser during cooling operation, and an evaporator during heating operation, (4) a receiver for storing liquid refrigerant,
(5) is an electric expansion valve having a function of reducing the pressure of the refrigerant and a function of adjusting the flow rate of the refrigerant, (6) is an indoor heat exchanger that is installed indoors and functions as an evaporator during cooling operation and as a condenser during heating operation, (7) is installed in the suction pipe of the compressor (1) and is an accumulator for removing the liquid refrigerant in the suction refrigerant.
It is.

The above-mentioned devices (1) to (7) are sequentially connected by a refrigerant pipe (8), and a refrigerant circuit (9) is constructed so as to cause heat transfer by circulation of the refrigerant. Incidentally, (13) is a supercooling capillary tube provided on the liquid pipe side of the outdoor heat exchanger (3).

On the discharge side of the compressor (1) of the refrigerant circuit (9), an oil recovery unit (10) for recovering the oil in the discharged refrigerant is provided. (10)
From the compressor to the suction pipe between the compressor (1) and the accumulator (7), an oil return passage (11) for returning the oil of the oil recovery device (10) to the suction side of the compressor (1) has a flow control valve. It is provided through (12).

In addition, in the liquid pipe of the refrigerant circuit (9), the receiver (4) and the electric expansion valve (5) are the lower portion of the receiver (4), that is, the liquid portion. Are arranged in series with the common path (8a) so as to communicate with the common path (8a).
The refrigerant from the outdoor heat exchanger (3) to the receiver (4) is provided between the outdoor heat exchanger (3) and the point (P), which is the upper end of the receiver (4) of a). Between the point (P) of the common path (8a) and the indoor heat exchanger (6) by the first inflow path (8b) via the first check valve (D1) that allows only the flow of While being connected by the second inflow passage (8c) via the second check valve (D2) that allows only the flow of the refrigerant from the heat exchanger (6) to the receiver (4), the common passage Point (Q) at the other end of the electric expansion valve (5) of (8a) and the first check valve (D1) -outdoor heat exchanger (3).
A third check valve (D) that allows only the refrigerant to flow from the electric expansion valve (5) to the outdoor heat exchanger (3) between the point (S) and the point (S).
3) via the first outflow path (8d) to the common path (8
From the electric expansion valve (5) to the indoor heat exchanger (6) between the point (Q) in a) and the point (R) between the second check valve (D2) and the indoor heat exchanger (6). The second outflow passages (8e) are connected to each other via the fourth check valve (D4) that allows only the flow of the refrigerant to and from the refrigerant. Also, one point (W) on the receiver upstream side of the common path (8a) and the fourth point of the second outflow path (8e).
A liquid-sealing prevention bypass passage (8f) provided with a capillary tube (C) is provided between the check valve (D4) and a point (U) on the upstream side, and the compressor (1 ) Is designed to prevent liquid sealing when stopped.

Further, sensors are arranged in the air conditioner, (Thd) is arranged in the discharge pipe of the compressor (1), a discharge pipe sensor for detecting the discharge pipe temperature, and (Thc) is outdoor. An external heat exchange sensor which is arranged in the liquid pipe of the heat exchanger (3) and detects the condensation temperature of the refrigerant during the cooling operation and the evaporation temperature of the refrigerant during the heating operation, (Tha) is the air intake of the outdoor heat exchanger (3) An outside air temperature sensor placed in the mouth to detect the outside air temperature,
(The) is arranged in the liquid pipe of the indoor heat exchanger (6), an internal heat exchange sensor for detecting the evaporation temperature during the cooling operation and the condensation temperature during the heating operation, and (Thr) is the air inside the indoor heat exchanger (6). A room temperature sensor arranged at the intake port for detecting the temperature of the intake air, wherein the sensors are connected to a controller (30) for controlling the operation of the air conditioner so that signals can be input. The controller (30) controls the operation of each device according to the signal from the sensor.

Further, (HPS) is a high pressure operating pressure switch (high pressure switch) as a first signal output means which operates when the high pressure side pressure reaches an upper limit and outputs a stop signal, (LP
S) is a low pressure operating pressure switch (low pressure switch) as a first signal output means that operates when the low pressure side reaches the lower limit and outputs a stop signal. Then, as shown in FIG. 3, in the controller (30), normally closed contacts (63H) and (63L) of the switches (HPS) and (LPS) are provided.
Is a protection circuit (31) together with a protection signal detection circuit (32)
Are connected in series. That is, when one of the switches (HPS) and (LPS) is opened, the protection circuit (31) is de-energized, and the interruption of the energization is detected as a stop signal by the signal detection circuit (32). Has been done. Further, in the signal detection circuit (32), there is provided a counter (33) as counting means for accumulating stop signals from the switches (HPS) and (LPS).

In the refrigerant circuit (9), during the cooling operation, the liquid refrigerant condensed and liquefied in the outdoor heat exchanger (3) flows from the first flow passage (8b) to the common passage (8a) and the receiver ( After being stored in 4) and decompressed by the electric expansion valve (5),
The circulation is returned to the compressor (1) by evaporating in the indoor heat exchanger (6) via the second outflow passage (8e). During the heating operation, the liquid refrigerant condensed and liquefied in the indoor heat exchanger (6) is
After flowing from the flow passage (8c) to the common passage (8a), stored in the receiver (4) and decompressed by the electric expansion valve (5),
The circulation is performed by evaporating in the outdoor heat exchanger (3) through the first outflow passage (8d) and returning to the compressor (1).

Next, the control contents of the controller (30) will be explained based on the flowcharts of FIGS. 4 to 6. FIG. 4 shows the contents of the high and low pressure protection control. In steps ST1 and ST2, the process proceeds to step ST3 only when the high pressure switch (HPS) or the low pressure switch (LPS) is activated.
Stop the compressor (1). Next, in step ST4, after the pressure protection counter flag FHLPS of the counter (33) is integrated, in step ST5, it is determined whether or not the counter flag FHLPS is 10 times or more, and FHLPS is determined.
Until PS ≧ 10, the process proceeds to step ST6, waits for 3 minutes, and then in step ST7, a recovery process for restarting the compressor (1) is performed. On the other hand, the above step ST5
If FHLPS ≧ 10 in the determination of No., the process proceeds to step ST8, the counter flag FHLPS is reset, and then in step ST9, an abnormal process of stopping the operation of each device of the refrigerating apparatus is performed.

Next, FIG. 5 shows a part of the room temperature control, in which the intake air temperature Tr detected by the indoor intake sensor (Thr).
When the temperature difference ΔTr between the room temperature Ts and the room temperature Ts exceeds the thermo-off set value continuously for a predetermined time, at step SR1, the temperature is turned on.
A mo-off signal is output, the counter flag FHLPS is reset in step SR2, and the thermo-off process is performed in steps SR3 and below by the following procedure. That is, step S
At R3, the electric expansion valve (5) is closed, and after waiting at step SR4 for 1.5 minutes, at step SR5, the compressor (1) is closed.
To stop the indoor fan (not shown) in step SR6.
Is set to a small air volume "LL", and an outdoor fan (not shown) is stopped in step SR7. Then, after waiting for 3 minutes in step SR8, a return process is performed in step SR9.

Further, the refrigerating apparatus has a built-in control for protecting each device in addition to the above high and low pressure protection. For example, in the abnormal protection control of the discharge pipe sensor (Th2) shown in FIG. If a sensor error occurs in SP1,
After proceeding to step SP2 to stop the compressor (1) and resetting the counter flag HHLPS in step SP3,
Abnormality processing is performed in step SP4. Also, the compressor (1)
The same process is performed when the current, the fan motor temperature switch, and other abnormalities occur inside the room. The counter flag FHLPS is also reset when the stop button is pressed.

In the above flow, the return processing means (51) of the present invention is constituted by the control of step ST7,
The control of step ST9 constitutes the abnormality processing means (52) of the present invention. The control of step SR1 constitutes the thermo signal output means (53) of the present invention, and the control of step SR2 constitutes the reset means (54) of the present invention.

Therefore, in the above embodiment, during operation of the refrigeration system, the high-pressure side pressure in the refrigerant circuit (9) excessively rises or the low-pressure side pressure excessively drops, so that the high pressure switch (HPS) or the low pressure switch (LPS). ) Is activated and a stop signal is output, a counter (3
By 3), the number of stop signals is integrated. And until this integrated value FHLPS reaches the set value (10 times) or more,
The return processing means (51) performs a return processing of stopping the compressor (1) for a predetermined time (3 minutes) and then starting it, while the integrated value FHLPS of the stop signal is a set value (10 times).
When the temperature reaches, the abnormality processing means (52) performs abnormality processing for stopping each device of the refrigeration system. In that case, since the condition that an excessive increase in the high-pressure side pressure and an excessive decrease in the low-pressure side pressure exist at the same time rarely occurs in experience, even if such unified control is performed, the abnormal process becomes complicated. There is no problem such as becoming. Therefore, the failure of the compressor (1) or the like due to some abnormality of the device is prevented, and a transient excessive increase in the high-pressure side pressure that occurs at the time of starting the heating operation under high outside air conditions or cooling under low outside air conditions. It is possible to prevent a problem in which a transient excessive decrease in the low-pressure side pressure that occurs at the time of starting operation is determined to be an abnormality of the device itself and is abnormally processed.

Further, the suction air temperature Tr detected by the indoor suction sensor (Thr) exceeds the indoor set temperature Ts, and the
When the thermo-off signal is output from the signal output means (53), the integrated value FHLPS of the stop signal integrated by the counter (33) is reset. That is, the output of such a thermo-off signal indicates that the operating state of the device has changed, and even if there is an abnormal state of high or low pressure, it has already exited from the abnormal state and is in normal conditions. It is safe to judge that. Therefore, by resetting the integrated value FHLPS of the counter (33) at the time when the thermo-off signal is output, the stop signal due to a transient error is integrated for a long time, resulting in unnecessary error processing. Can be prevented. In addition, in the case of resetting the integrated value when the set time has elapsed, the time interval at which the high-pressure side abnormality occurs and the time interval at which the low-pressure side abnormality occurs do not necessarily match, so such a unified protection control If you try to reset the integrated value due to a change in the operating state due to the output of the thermo-off signal, a high pressure switch (HPS) And the stop signal of the low-voltage switch (LPS) can be processed on the same basis, and there is no room for such a problem.

Therefore, by integrally performing protection control based on the stop signals from the high-voltage switch (HPS) and the low-voltage switch (LPS), it is possible to avoid an abnormal stop of the device due to a temporary high-low pressure abnormality. It is possible to simplify the circuit configuration and control contents without deteriorating the refrigerating effect and reducing the reliability.

[0026]

As described above, according to the present invention,
As a protection device for the refrigeration system, a stop signal is output in response to an excessive increase in the high-pressure side pressure and an excessive decrease in the low-pressure side pressure, and while the compressor is stopped for a predetermined time in response to the stop signal, a recovery process is performed. When the integrated value of the stop signal exceeds the set value, each device of the refrigeration system is abnormally stopped, and when the thermo-off signal from the room is output, the integrated value of the stop signal is reset. By uniformly processing the stop signal due to the abnormal condition, the circuit individuality and the control content can be simplified while surely avoiding the unnecessary abnormal stop of the device due to the temporary abnormal condition.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of the invention.

FIG. 2 is a refrigerant piping system diagram of the air conditioning apparatus according to the embodiment.

FIG. 3 is an electric circuit diagram of a high / low voltage protection circuit.

FIG. 4 is a flowchart showing the contents of high / low voltage protection control.

FIG. 5 is a flowchart showing a part of room temperature control.

FIG. 6 is a flowchart showing the content of discharge tube sensor abnormality protection control.

[Explanation of symbols]

 1 Compressor 3 Outdoor Heat Exchanger (Condenser or Evaporator) 5 Electric Expansion Valve (Decompression Valve) 6 Indoor Heat Exchanger (Evaporator or Condenser) 9 Refrigerant Circuit 33 Counter (Counting Means) 51 Recovery Processing Means 52 Abnormality Processing means 53 Thermo signal output means 54 Reset means HPS high voltage switch (first signal output means) LPS low voltage switch (second signal output means)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Wada 1304 Kanaoka-machi, Sakai-shi, Osaka Daikin Industrial Co., Ltd. Sakai Works Kanaoka factory

Claims (1)

(57) [Claims] 1. A refrigeration system comprising a refrigerant circuit (9) in which a compressor (1), a condenser (3 or 6), a pressure reducing mechanism (5) and an evaporator (6 or 3) are sequentially connected, First signal output means (HPS) that outputs a stop signal when the high-pressure side pressure becomes equal to or higher than the upper limit value, and second signal output means (LPS) that outputs a stop signal when the low-pressure side pressure becomes equal to or lower than the lower limit value. When receiving a stop signal from the signal output means (HPS) and (LPS), a recovery processing means (51) for controlling the compressor (1) to stop for a predetermined time and then restart it, and the both signal outputs. Counting means (33) for collectively integrating the number of stop signal outputs by means (HPS), (LPS), and when the integrated value of the stop signals accumulated by the counting means (33) reaches or exceeds a set value Then, the control of the return processing means (51) is forcibly stopped, and An abnormality processing means (52) for controlling the operation of each device to stop abnormally, a thermo signal output means (53) for outputting a thermo-off signal based on the temperature difference between the room temperature and the room set temperature, and A reset means (54) for resetting the integrated value of the counting means (33) when a thermo-off signal from the thermo signal output means (53) is received or when the refrigeration system is abnormally stopped. Refrigerator protection device.