JPH0599543A - Protection device for refrigerator - Google Patents

Abstract

PURPOSE:To prevent troubles such as damage due to burning caused by the dropping of a discharge pipe sensor of a refrigerator, etc., before they occur. CONSTITUTION:A coolant circuit 9 is constituted by connecting a compressor 1, electromotive expansion valve 5, etc. successively, and the operation of a refrigerating device is stopped due to abnormality by a protection device 11 when a value of detection by a discharge pipe sensor Th 2 becomes larger than a specified value. When the difference of the temperature detected by the sensor Th 2 of the compressor 1 when a specified time has passed after starting the compressor 1 and the temperature at starting is lower than a specified temperature, the refrigerator is stopped due to abnormality by an abnormality handling means 53. With this arrangement the state of dropping the discharge pipe sensor Th 2 is detected for sure, and damage to the compressor 1 by burning, etc., are prevented before they occur. When the temperature detected by the discharge pipe sensor Th 2 when a specified time has passed after starting is lower than a specified temperature, or when it is lower than the temperature that is given by adding certain temperature to the outside temperature the stopping due to abnormality can be made. Especially, it is effective when the degree of opening of the electromotive expansion valve 5 is controlled so as to make the temperature of the discharge pipe converge to a target control value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protection device for a refrigerating device which controls a discharge pipe temperature, and more particularly to a burnout prevention measure for a compressor caused by removal of a discharge pipe temperature sensor.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Publication No. Sho 59-1294.
As disclosed in Japanese Unexamined Patent Publication No. 2 (1998), as an operation control device of a refrigeration system including a refrigerant circuit in which a compressor, a condenser, an electric expansion valve, and an evaporator are sequentially connected, based on the evaporation temperature and the condensation temperature of the refrigerant circuit. A constant capacity compressor is used by calculating the optimum temperature of the discharge pipe temperature of the compressor that gives the maximum refrigeration effect and controlling the opening of the electric expansion valve using this optimum temperature as the control target value of the discharge pipe temperature. However, it is a known technique to maintain good refrigerating capacity and operating efficiency of the refrigerating apparatus.

[0003]

By the way, in a refrigeration system, a discharge pipe sensor attached to a discharge pipe of a compressor is usually used for operating a protective device, and is compressed due to lack of a refrigerant or the like. When the internal temperature of the machine rises excessively, the protection device is activated by the signal of the discharge pipe sensor to stop the operation of the refrigeration system.

However, the discharge pipe sensor may come off from the discharge pipe due to an installation error or the like during installation of the refrigeration system or an accident during operation. In such a case, even if the internal temperature of the compressor rises excessively, Since the detection value of the sensor hardly changes, the protective device does not operate, and as a result, there is a possibility that an accident such as burnout of the compressor may occur.

Particularly, in the case of controlling the discharge pipe temperature of the compressor by the target value by the opening degree of the electric expansion valve as in the above publication, the opening degree of the electric expansion valve is narrowed when the detection value of the discharge pipe sensor is low. Since it is controlled in the direction, if the operation is continued as it is, there is a problem that the refrigerant in the compressor is gradually reduced and the risk of the compressor being burned out is very high.

The present invention has been made in view of the above problems, and an object of the present invention is to prevent burnout of a compressor in advance by providing a means for surely detecting that the discharge pipe sensor is disengaged from the discharge pipe. To prevent.

[0007]

Means for Solving the Problems To achieve the above object, the means taken by the invention of claim 1 is, as shown in FIG. 1 (not including a dotted line portion), a compressor (1), a heat source side. A refrigeration system provided with a refrigerant circuit (9) in which a heat exchanger (3), an electric expansion valve (5), and a use side heat exchanger (6) are sequentially connected is assumed.

As an operation control device for the refrigeration system,
The discharge pipe temperature sensor (Th2) attached to the discharge pipe (8d) of the compressor (1) for detecting the discharge pipe temperature and the output of the discharge pipe temperature sensor (Th2) receive the discharge pipe temperature at a predetermined temperature. When the above is reached, there is provided a protection means (11) which operates to stop the operation of the refrigeration system.

Further, a predetermined time has elapsed after the compressor (1) was started up by receiving the time-measuring means (12) for measuring the elapsed time after the start-up of the compressor (1) and the output of the timekeeping means (12). When the temperature difference between the detection value of the discharge pipe sensor (Th2) at time and the detection value of the discharge pipe sensor (Th2) at the time of starting the compressor (1) is equal to or less than a certain temperature difference, an abnormality that abnormally stops the refrigeration system The processing means (53A) is provided.

The means taken by the invention of claim 2 presupposes a refrigerating apparatus similar to that of the invention of claim 1, and as an operation control device for the refrigerating apparatus, as shown in FIG. 1 (not including the dotted line portion). , A discharge pipe temperature sensor (Th2) attached to the discharge pipe (8d) of the compressor (1) for detecting the discharge pipe temperature
And a protection means (11) which receives the output of the discharge pipe temperature sensor (Th2) and operates to stop the operation of the refrigeration system when the discharge pipe temperature reaches a predetermined temperature or higher. 1) A time measuring means (1) for measuring an elapsed time after starting
2) and the output of the time measuring means (12), and when the detection value of the discharge pipe sensor (Th2) is equal to or less than a predetermined value when a predetermined time has elapsed after the compressor (1) is started, the refrigeration system is operated. An abnormality processing means (53B) for abnormally stopping is provided.

The means taken by the invention of claim 3 presupposes a refrigerating apparatus similar to that of the invention of claim 1, and the discharge pipe (8d) of the compressor (1) is used as an operation control device of the refrigerating apparatus.
Attached to the discharge pipe temperature sensor (Th2) for detecting the discharge pipe temperature, and the output of the discharge pipe temperature sensor (Th2). When the discharge pipe temperature reaches or exceeds a predetermined temperature, the refrigerator operates to operate the refrigeration system. And a protection means (11) for stopping the
Further, as shown by a dotted line in FIG. 1, an outside air temperature detecting means (Tha) for detecting an outside air temperature, a time measuring means (12) for measuring an elapsed time after the compressor (1) is started, and the time measuring means ( 12) The output value of the discharge pipe sensor (Th2) when a predetermined time has elapsed after the compressor (1) is started after receiving the output of 12) is a constant value for the outside air temperature detected by the outside air temperature detecting means (Tha). When the temperature is lower than the temperature obtained by adding, the abnormality processing means (53C) for abnormally stopping the refrigeration system is provided.

According to the invention of claim 4, in the invention of claim 1, 2 or 3, the means for taking measures according to the condensation temperature, the evaporation temperature, etc. of the refrigerant circuit (1) is shown in the broken line part of FIG. And the output of the discharge pipe temperature sensor (Th2) and the optimum temperature calculation means (51) that calculates the optimum temperature of the discharge refrigerant temperature that gives the optimum refrigeration effect, and the discharge pipe temperature is the optimum temperature calculation means (51). ), The opening degree control means (52) for controlling the opening degree of the electric expansion valve (5) is provided so as to converge to the optimum temperature calculated in (1).

[0013]

With the above construction, in the invention of claim 1, when the discharge pipe temperature detected by the discharge pipe sensor (Th2) becomes a predetermined temperature or more during the operation of the refrigeration system, the protection means (11) causes the freezing to be performed. The device is stopped abnormally and the compressor (1) is protected, but if the discharge pipe sensor (Th2) is detached from the discharge pipe (8d), the detected value of the discharge pipe sensor (Th2) is the actual discharge temperature. Will have a different value. In particular, electric expansion valve (5)
The degree of opening of the refrigerant may change depending on the operating condition, and the amount of refrigerant circulation may decrease and the compressor (1) may overheat and the discharge pipe temperature may rise excessively. However, the protective device (11) does not operate, and there is a risk that an accident such as burnout of the compressor (1) will occur.

Here, in a state where the discharge pipe sensor (Th2) is correctly attached to the discharge pipe (8d), the discharge pipe temperature after a lapse of a fixed time after the start of the compressor (1) and the discharge pipe temperature at the time of start. Since the temperature difference between and the temperature should reach a considerable temperature, it is highly possible that the discharge pipe sensor (Th2) has fallen off when the temperature difference between the two is less than a certain temperature difference. Therefore, the air conditioner is abnormally stopped by the abnormality processing means (53A), whereby the burnout of the compressor (1) is prevented in advance.

According to the second aspect of the present invention, the inside of the compressor (1) is normally warmed when a predetermined time has elapsed after the compressor (1) is started, and the discharge pipe temperature should reach a certain temperature or higher. When the detection value of the discharge pipe sensor (Th2) is less than or equal to the predetermined value, it is highly likely that the discharge pipe sensor (Th2) has fallen off the discharge pipe (8d). Therefore, the air conditioner is abnormally stopped by the abnormality processing means (53B), so that the burnout of the compressor (1) is prevented in advance.

In the invention of claim 3, the discharge pipe sensor (Th
When 2) falls off from the discharge pipe (8d), the temperature of the discharge pipe (8d) approaches the outside air without limit. If not, the discharge pipe sensor (T
It is very likely that h2) is missing. Therefore,
By abnormally stopping the air conditioner by the abnormality processing means (53C), burnout of the compressor (1) is prevented in advance.

According to a fourth aspect of the present invention, in the first, second or third aspect of the present invention, the optimum temperature calculating means (51) is used to optimize the discharge pipe temperature that provides the optimum refrigerating effect based on the evaporation temperature, the condensation temperature and the like. When the temperature is calculated and the opening control means (52) controls the opening of the electric expansion valve (5) so that the discharge pipe temperature converges to this optimum temperature, the discharge pipe sensor (Th2) If it falls and the detected value is lower than the actual discharge pipe temperature, the apparent discharge pipe temperature becomes smaller than the control target value, and the opening degree of the electric expansion valve (5) is closed. Therefore, if the operation is continued as it is, the refrigerant is rapidly reduced, and there is a high risk that the compressor (1) will be overheated and burned in a short time. Due to the action, accidents such as burnout of the compressor (1) are prevented in advance.

[0018]

Embodiments of the present invention will be described below with reference to FIG.

FIG. 1 shows a refrigerant piping system of an air conditioner to which the present invention is applied, which is a so-called separate type in which one indoor unit (A) is connected to one indoor heat exchanger (B). belongs to. The outdoor unit (A) includes a compressor (1), a four-way switching valve (2) that switches as shown by a solid line in the figure during a cooling operation, and a broken line in the figure as a heating operation, and as a condenser during a cooling operation. The outdoor heat exchanger (3), which is a heat source side heat exchanger that functions as an evaporator during heating operation, and a decompression unit (20) for decompressing the refrigerant.
And an accumulator (7) for removing the liquid refrigerant in the suction refrigerant, which is interposed in the suction pipe of the compressor (1), is arranged as a main device. Also, in the indoor unit (B), An indoor heat exchanger (6), which is a utilization side heat exchanger that functions as an evaporator during cooling operation and as a condenser during heating operation, is arranged. Each of the above equipment is a refrigerant pipe (8)
A refrigerant circuit (9) is constructed in which the refrigerant circuits (9) are sequentially connected to each other to cause heat transfer by circulation of the refrigerant.

The pressure reducing section (20) is provided with a receiver (4) for storing the liquid refrigerant and an electric expansion valve (5) having a pressure reducing function and a flow rate adjusting function for the liquid refrigerant. The receiver (4) and the electric expansion valve (5) are disposed so that the electric expansion valve (5) communicates with the lower portion of the receiver (4), that is, the liquid portion. ) Auxiliary heat exchanger (3a)
Are arranged in series on the common path (8a). Then, between the outdoor end (P) of the receiver (4) upstream of the common path (8a) and the outdoor heat exchanger (3), the outdoor heat exchanger (3) goes to the receiver (4). Between the point (P) of the common path (8a) and the indoor heat exchanger (6) by the first inflow path (8b1) via the first check valve (D1) that allows only the circulation of the refrigerant of Is from the indoor heat exchanger (6) to the receiver (4)
The electric expansion valve (5) and the like on the common path (8a), while being connected to each other by the second inflow path (8b2) through the second check valve (D2) that allows only the flow of the refrigerant to the Between the end portion (Q) on the end side and the point (R) between the second check valve (D2) and the indoor heat exchanger (6), the electric expansion valve (5) is connected to the indoor heat exchanger (6). The first check valve (D1) and the point (Q) of the common path (8a) by the first outflow passage (8c1) through the third check valve (D3) that allows only the flow of the refrigerant to the first check valve (D1). A fourth check valve (D4) which allows only the flow of the refrigerant from the electric expansion valve (5) to the outdoor heat exchanger (3) between the outdoor heat exchanger (3) and the point (S). Through the 2nd outflow path (8c2)
Are connected to each other.

Further, a capillary tube (C) is interposed between a point (P) on the upstream side and a point (Q) on the outflow side of the receiver (4) to prevent liquid sealing. Bypass road (8f)
Is provided, the liquid sealing prevention bypass passage (8f) prevents liquid sealing when the compressor (1) is stopped, and the gas refrigerant flows from the upper portion of the receiver (4) to the first outflow passage (8c1). ) Is able to move to the side. The degree of pressure reduction of the capillary tube (C) is set to be sufficiently larger than that of the electric expansion valve (5), so that the electric flow expansion function of the electric expansion valve (5) during normal operation can be improved. It is designed to be maintainable.

Incidentally, (F1) to (F4) are filters for removing dust in the refrigerant, and (ER) is a silencer for reducing the operation noise of the compressor (1).

Further, the air conditioner is provided with sensors, (Th2) is arranged in the discharge pipe, a discharge pipe sensor for detecting the discharge pipe temperature T2, and (Tha) is air of the outdoor unit (A). The outdoor suction sensor (Thc), which is arranged at the suction port and detects the intake air temperature Ta that is the outside air temperature, is arranged in the outdoor heat exchanger (3) and becomes the condensation temperature during the cooling operation and the evaporation temperature during the heating operation. An external heat exchange sensor for detecting the heat exchange temperature Tc, (Thr) is arranged at the air intake port of the indoor unit (B), and is the intake air temperature T that is the indoor temperature.
The indoor suction sensor for detecting r, (The) is arranged in the indoor heat exchanger (6), and detects the internal heat exchange temperature Te that becomes the condensation temperature during the cooling operation and becomes the evaporation temperature during the heating operation, ( (HPS) is a high pressure switch that is turned on by an excessive increase in the high pressure side pressure to activate the protection device (11), and (LPS) is turned on by an excessive decrease in the low pressure side pressure and activates the protection device (11). It is a low pressure switch that allows. The signals (10) of each sensor are connected to a controller that controls the operation of the air conditioner, and the controller (10) outputs signals of the air conditioner according to the signals of each sensor. It is designed to control driving.

In the controller (10),
A protection device (11) as a protection means according to the invention of claims 1 to 3, which is activated when an abnormality occurs during operation of the air conditioner to abnormally stop the air conditioner, and a timekeeping means for measuring time. And a timer (12) as. Although not shown, the protection device (11) is also supplied with signals from the discharge pipe sensor (T2) in addition to the high and low pressure switches (HPS) and (LPS), and the discharge pipe temperature T2 is a predetermined temperature. In the above case, the protection device (11) operates to abnormally stop the air conditioner and prevent accidents such as burnout of the compressor (1).

FIG. 3 shows a state in which the discharge pipe sensor (Th2) is attached to the discharge pipe. The discharge pipe sensor (Th2) is attached to the discharge pipe (8d) by a temperature-sensitive tube mounting pipe (21). Insulation pipe (22) inserted from the outside and further from the outside
Is attached to fix the discharge pipe sensor (Th2). In addition, (23) is a sensor mounting spring member.

In the refrigerant circuit (9), during the cooling operation, the liquid refrigerant condensed and liquefied in the outdoor heat exchanger (3) flows in from the first inflow passage (8b1), and the first check valve (D1) is turned on. After being stored in the receiver (4) and decompressed by the electric expansion valve (5), it is evaporated in the indoor heat exchanger (6) through the first outflow passage (8c1) and returned to the compressor (1). While becoming a cycle,
During the heating operation, the liquid refrigerant condensed and liquefied in the indoor heat exchanger (6) flows in from the second inflow passage (8b2), is stored in the receiver (4) via the second check valve (D2), After the pressure is reduced by the electric expansion valve (5), it is circulated through the second outflow passage (8c2) to evaporate in the outdoor heat exchanger (3) and return to the compressor (1).

Here, the control contents of the controller (10) will be described. FIG. 4 shows the controller (1
0) shows the control contents during the cooling operation of step 0),
At T1, the evaporation temperature Te detected by the inner heat exchange sensor (The) and the condensation temperature T detected by the outer heat exchange sensor (Thc)
c and the discharge pipe temperature T detected by the discharge pipe sensor (Th2)
2 is input, and in step ST2, the optimum temperature Tk that is the discharge pipe temperature that gives the optimum refrigerating effect EER is calculated based on the following equation (1) Tk = 4-1.13Te + 1.72Tc (1).

Then, in step ST3, the expression ΔT2 =
After calculating the temperature difference ΔT2 between the discharge pipe temperature T2 and the optimum temperature Tk based on T2-Tk, in step ST4, | ΔT
2 | ≦ 5, that is, the discharge pipe temperature T2 is the optimum temperature Tk
It is determined whether or not it has converged within a certain range above and below, and until it converges, the process proceeds to step ST5 and whether or not ΔT2 is positive,
That is, it is determined whether or not the discharge pipe temperature T2 is higher than the optimum temperature Tk, and if the discharge pipe temperature T2 is higher, step S
At T6, the electric expansion valve (5) is controlled to open to the middle level, while if the discharge pipe temperature T2 is lower, step ST7.
Then, the opening degree of the electric expansion valve (5) is controlled so as to be closed to an intermediate degree.

On the other hand, in the determination in step ST4, | Δ
When T2 | ≦ 5 and the discharge pipe temperature T2 converges within a certain range above and below the optimum temperature Tk, the process proceeds to step ST8, and although not described in detail, the opening degree of the electric expansion valve (5) is finely adjusted. Perform fuzzy control.

In the above flow, the optimum temperature calculating means (5) according to the invention of claim 4 is controlled by the control of step ST2.
1) is configured, and the opening degree control means (52) according to the invention of Claim 2 is configured by the control of steps ST4 to ST8.

Next, the content of the dropout detection control of the discharge pipe sensor (Th2) will be described based on the flowchart of FIG. First, in step SS1, it is determined whether or not 5 minutes have elapsed after the start of the air conditioner, and the process proceeds to step SS10 to perform normal operation until 5 minutes have elapsed. Then, when 5 minutes have passed after the startup, steps SS2 to SS
In step 5, whether or not the defrost operation is in progress, T2-To2≤5
(° C) (however, T2 is the discharge pipe temperature when 5 minutes have elapsed after startup, To2 is the discharge pipe temperature at startup),
Whether or not T2 <55 (° C.) or T2 <Ta + 10 is determined, and if any one of the determination results is NO, the process proceeds to step SS10 and the normal operation is performed, while each step SS2 When all the determination results in SS5 to NO are NO, the process proceeds to step SS6, and the number of detection times Fg counted by a counter (not shown) is integrated. Then, in step SS7, it is determined whether or not Fg ≧ 6, and until Fg ≧ 6, the process proceeds to step SS8, the thermo-off operation is performed for a certain period of time, and then the above-described control of dropout detection is repeated, When Fg ≧ 6, that is, after performing 6 retries, the above steps SS2 to S are still performed.
When the condition of S5 is satisfied, the discharge pipe sensor (T
It is determined that h2) has fallen out of the discharge pipe (8d), the process proceeds to step SS9, and abnormal processing for abnormally stopping the air conditioner is performed.

In the above flow, the abnormality processing means (53A) according to the invention of claim 1 is constituted by the control from step SS3 to SS9, and steps SS4 to S4.
The control toward S9 constitutes the abnormality processing means (53B) according to the invention of claim 2, and steps SS5 to SS
The control toward 9 constitutes the abnormality processing means (53C) according to the invention of claim 3.

Therefore, in the above embodiment, when the discharge pipe temperature T2 detected by the discharge pipe sensor (Th2) becomes higher than the predetermined temperature during the operation of the air conditioner, the controller (1
The protection device (11) built in 0) is activated, the air conditioner is abnormally stopped, and the compressor (1) is protected. However, if the discharge pipe sensor (Th2) is detached from the discharge pipe (8d), the detected value T2 of the discharge pipe sensor (Th2) becomes a value different from the actual discharge temperature, so the compressor (1) Is overheated and the discharge pipe temperature is excessively increased, the detected value T2 is low. Therefore, the protective device (11) does not operate and may cause an accident such as burnout of the compressor (1). However, in the above-described embodiment, the discharge pipe sensor (Th2) is determined by the determination in each of steps SS2 to SS5. Is detected,
Since the air conditioner is abnormally stopped by the abnormality processing means (53), burnout of the compressor (1) is prevented in advance.

Here, in the control of step SS2, it is determined whether or not the defrosting operation is being performed, because the refrigerant circulation amount becomes extremely large during the defrosting operation, so that the discharge pipe temperature T
This is to prevent an erroneous detection in which it is determined that the discharge pipe sensor (Th2) is normally attached but has fallen off in the determination in the later step, since 2 may be extremely low.

Further, according to the control of step SS3,
Corresponding to the invention of No. 2, whether or not T2-To2 ≤ 5 (° C) is determined is that, after 5 minutes have passed after the start, the discharge pipe temperature To2 at the time of start is about 10 ° C under normal conditions. Tube temperature T
Because there should be an increase of 2, T2-To2 ≤ 5
This is because if the temperature is (° C.), it is highly likely that the discharge pipe sensor (Th2) has fallen off.

Further, in the control of step SS4,
According to the invention of (1), whether or not T2 <55 (° C.) is determined is because the discharge pipe temperature T2 is not lower than 55 ° C. after the start of the normal compressor (1). T2 <
This is because it is very likely that the discharge pipe sensor (Th2) has fallen off at 55 (° C).

Further, in the control of step SS5, it is determined whether T2 <Ta + 10 or not in accordance with the invention of claim 3 when the discharge pipe sensor (Th2) falls off from the discharge pipe (8d). Infinitely close to the outside air temperature Ta, and when 5 minutes have passed, it is 10 ° C higher than the outside air temperature.
This is because there is a high possibility that the discharge pipe sensor (Th2) has fallen off when the temperature does not rise above the above.

In particular, as in the above embodiment, the optimum temperature calculating means (51) calculates the optimum temperature Tk of the discharge pipe temperature T2 which gives the optimum refrigerating effect based on the evaporation temperature Te, the condensation temperature Tc and the like. When the opening control means (52) controls the opening of the electric expansion valve (5) so that the discharge pipe temperature T2 converges to the optimum temperature Tk, the discharge pipe sensor (Th2) falls off. If the detected value T2 is lower than the actual discharge pipe temperature, Δ in the control flow of FIG.
T2 becomes smaller than actual, and as a result, step ST
By the control of 7, the opening degree of the electric expansion valve (5) is closed. Therefore, if the operation is continued as it is, the refrigerant is rapidly reduced, and there is a high risk that the compressor (1) will be overheated and burned in a short time. Therefore, by applying the control for detecting the drop of the discharge pipe sensor (Th2) to the system for controlling the discharge pipe temperature as described above, the remarkable effect can be exhibited.

The method of calculating the optimum temperature Tk is not limited to the above-mentioned embodiment, and it is also possible to perform a calculation such as correction with the outside air temperature Ta.

Further, in the above embodiment, in the control flow of FIG. 5, the abnormality process of step SS9 is performed only when the determination results of steps SS3 to SS5 are all NO. The present invention is not limited to this embodiment, and only one of the steps SS3 to SS5 may be determined, and when the result of the determination is NO, the process may proceed to step SS9.

[0041]

As described above, according to the invention of claim 1, the refrigeration provided with the refrigerant circuit in which the compressor, the heat source side heat exchanger, the electric expansion valve and the utilization side heat exchanger are sequentially connected. As the operation control device of the device, when the discharge pipe temperature detected by the discharge pipe sensor becomes equal to or higher than a predetermined temperature during operation of the refrigeration device,
While providing a protective means for abnormally stopping the refrigeration system, if the temperature difference between the detection value of the discharge pipe sensor after the elapse of a certain time after the start of the compressor and the detection value at the start is less than a certain temperature difference, the operation of the refrigeration system Since it is configured to stop abnormally, it is possible to reliably detect a mistake during installation of the discharge pipe sensor or a dropout due to an accident during operation, and prevent accidents such as burnout of the compressor due to excessive rise in internal temperature of the compressor. can do.

According to the second aspect of the present invention, the refrigeration is used as the operation control device of the refrigeration system including the refrigerant circuit in which the compressor, the heat source side heat exchanger, the electric expansion valve and the utilization side heat exchanger are sequentially connected. During operation of the device, if the discharge pipe temperature detected by the discharge pipe sensor exceeds a predetermined temperature, protective means is provided to abnormally stop the refrigeration system, while the value detected by the discharge pipe sensor after a lapse of a predetermined time after starting the compressor When the value is less than a predetermined value, the operation of the refrigeration system is stopped abnormally, so it is possible to reliably detect the falling state of the discharge pipe sensor and prevent accidents such as burnout due to an excessive rise in the internal temperature of the compressor. can do.

According to the third aspect of the invention, the refrigeration is used as the operation control device of the refrigeration system provided with the refrigerant circuit in which the compressor, the heat source side heat exchanger, the electric expansion valve and the utilization side heat exchanger are sequentially connected. During operation of the device, if the discharge pipe temperature detected by the discharge pipe sensor exceeds a predetermined temperature, a protective means is provided for abnormally stopping the refrigeration system, while the detection value of the discharge pipe sensor is detected after a lapse of a predetermined time after starting the compressor. When the temperature is lower than the temperature obtained by adding a certain value to the outside air temperature, the operation of the refrigeration system is stopped abnormally, so the dropout state of the discharge pipe sensor can be reliably detected and the internal temperature of the compressor is excessively increased to cause burnout. It is possible to prevent such accidents.

According to the invention of claim 4, the above-mentioned claim 1,
Since the invention of 2 or 3 is applied to the one having the system for controlling the opening degree of the electric expansion valve so that the discharge pipe temperature converges to the optimum temperature, the apparent discharge pipe temperature is smaller than the control target value. As a result, the opening of the electric expansion valve is closed, and even if there is a high risk that the compressor will overheat and burn out in a short time due to the rapid decrease in refrigerant, an accident such as burnout of the compressor will occur. This can be prevented in advance, and thus the remarkable effects of each of the above inventions can be exhibited.

[Brief description of drawings]

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

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

FIG. 3 is an exploded perspective view showing how the discharge pipe sensor is attached to the discharge pipe.

FIG. 4 is a flowchart showing the contents of discharge pipe temperature control.

FIG. 5 is a flowchart showing the details of dropout detection control of the discharge pipe sensor.

[Explanation of symbols] 1 compressor 3 outdoor heat exchanger (heat source side heat exchanger) 5 electric expansion valve 6 indoor heat exchanger (use side heat exchanger) 9 refrigerant circuit 11 protection device (protection means) 12 timer (timekeeping) 51) Optimum temperature calculation means 52 Opening degree control means 53 Abnormality processing means Th2 Discharge pipe sensor Tha Outdoor suction sensor (outside air temperature detection means)

Front page continued (72) Inventor Masami Horiuchi 1304 Kanaoka-cho, Sakai City, Osaka Daikin Industries, Ltd.Kanaoka Plant, Sakai Manufacturing Co., Ltd. (72) Takeo Ueno 1304, Kanaoka-cho, Sakai City, Osaka Daikin Industries, Inc. in the factory

Claims (4)

[Claims] 1. A compressor (1), a heat source side heat exchanger (3),
A refrigerating apparatus provided with a refrigerant circuit (9) in which an electric expansion valve (5) and a use side heat exchanger (6) are sequentially connected to each other, which is attached to a discharge pipe (8d) of the compressor (1) to discharge A discharge pipe temperature sensor (Th2) for detecting the pipe temperature, and a protection means for receiving the output of the discharge pipe temperature sensor (Th2) and operating when the discharge pipe temperature reaches or exceeds a predetermined temperature to stop the operation of the refrigeration system. (11), and a timer (12) for measuring an elapsed time after starting the compressor (1), and an output of the timer (12) for receiving a predetermined time after starting the compressor (1). When the temperature difference between the detection value of the discharge pipe sensor (Th2) when the temperature has passed and the detection value of the discharge pipe sensor (Th2) at the time of starting the compressor (1) is equal to or less than a certain temperature difference, the refrigeration system is abnormal. It is equipped with an abnormality processing means (53A) for stopping. Characterizing device for refrigeration equipment. 2. A compressor (1), a heat source side heat exchanger (3),
A refrigerating apparatus provided with a refrigerant circuit (9) in which an electric expansion valve (5) and a use side heat exchanger (6) are sequentially connected to each other, which is attached to a discharge pipe (8d) of the compressor (1) to discharge A discharge pipe temperature sensor (Th2) for detecting the pipe temperature, and a protection means for receiving the output of the discharge pipe temperature sensor (Th2) and operating when the discharge pipe temperature reaches or exceeds a predetermined temperature to stop the operation of the refrigeration system. (11), and a timer (12) for measuring an elapsed time after starting the compressor (1), and an output of the timer (12) for receiving a predetermined time after starting the compressor (1). When the detected value of the discharge pipe sensor (Th2) is equal to or less than a predetermined value after the passage of, the refrigerating device protection device is provided with an abnormality processing means (53B) for abnormally stopping the refrigerating device. 3. A compressor (1), a heat source side heat exchanger (3),
A refrigerating apparatus provided with a refrigerant circuit (9) in which an electric expansion valve (5) and a use side heat exchanger (6) are sequentially connected to each other, which is attached to a discharge pipe (8d) of the compressor (1) to discharge A discharge pipe temperature sensor (Th2) for detecting the pipe temperature, and a protection means for receiving the output of the discharge pipe temperature sensor (Th2) and operating when the discharge pipe temperature reaches or exceeds a predetermined temperature to stop the operation of the refrigeration system. (11), the outside air temperature detecting means (Tha) for detecting the outside air temperature, and the time measuring means (1) for measuring the elapsed time after the start of the compressor (1).
2) and the output of the time measuring means (12), the detected value of the discharge pipe sensor (Th2) at the time when a predetermined time has elapsed after the compressor (1) is started is the outside air temperature detecting means (Tha). A protection device for a refrigeration system, comprising: an abnormality processing means (53C) for abnormally stopping the refrigeration system when the temperature is lower than a temperature obtained by adding a constant value to the detected outside air temperature. 4. The protection device for a refrigerating apparatus according to claim 1, 2 or 3, wherein an optimum temperature of a discharge refrigerant temperature that gives an optimum refrigerating effect is set in accordance with a condensation temperature, an evaporation temperature, etc. of the refrigerant circuit (1). The electric expansion valve receives the outputs of the optimum temperature calculation means (51) for calculation and the discharge pipe temperature sensor (Th2) and converges the discharge pipe temperature to the optimum temperature calculated by the optimum temperature calculation means (51). Opening control means (5) for controlling the opening of (5)
2) A protection device for a refrigeration system, which is provided with.