JPS63194173A - Trouble detector for electric expansion valve in refrigerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a failure detection device for an electric expansion valve in a refrigeration system.・ (Prior art) Conventionally, in a refrigeration system, especially an air conditioner, a compressor, a condenser, an expansion mechanism, and an evaporator are used, as disclosed in, for example, Japanese Patent Application Laid-open No. 58-205057@. A refrigerant circulation system is formed by sequentially connecting to a closed circuit, and the expansion FM structure is configured with an electric expansion valve whose opening degree can be adjusted electrically,
The opening degree of this electric expansion valve is the degree of superheating of the refrigerant (state quantity of the refrigerant).
By controlling the increase/decrease according to the amount of air, comfortable air conditioning can be achieved by appropriately responding to indoor load fluctuations.

(Problems to be Solved by the Invention) When a refrigeration system malfunctions, it is necessary for a service person to check and determine whether or not there is a malfunction in the electric expansion valve in order to find the location of the malfunction.

However, in that case, the opening degree of the electric expansion valve is controlled by installing a CPU on an electronic control board in the control device, and sending a control signal from the CPU to the electric expansion valve to rotate its rotation axis in the forward and reverse directions. Due to the fact that the valve opening is adjusted to increase or decrease, even if there is no change in the opening of the electric expansion valve, the service engineer must check whether there is a true malfunction or whether the control signal is not being sent. It cannot be easily determined whether the opening degree simply does not change. Furthermore, the method of controlling the opening of the electric expansion valve includes refrigerant superheating control, discharge pipe temperature control, etc., and the manner in which the valve opening changes depending on each control is different. In the case of a malfunction in which the movement of the electric expansion valve is locked, or in a normal situation where there is no change in the opening, a service person should know the above method of controlling the valve opening and identify the characteristics of the change in the valve opening. Without accurate recognition, it will be extremely difficult to determine the presence or absence of a failure.

The present invention has been made in view of this point, and utilizes the fact that when the opening degree of the electric expansion valve changes, the state quantities (temperature, pressure, etc.) of the refrigerant in the refrigerant circulation system also change. The purpose is to forcibly change the opening degree of the electric expansion valve based on manual operation by a service person when it is necessary to determine whether there is a failure or not. By making it possible to confirm this, it is possible to easily determine whether or not there is a failure in the electric expansion valve, thereby improving serviceability.

(Means for solving the problem) In order to achieve the above object, the solving means of the present invention includes an electric expansion valve (3) disposed in a refrigerant circulation system (8), as shown in FIG. A refrigeration system is assumed to be provided with an opening degree control means (23) that controls the opening degree of the electric expansion valve (3) according to the operating state. Then, operation means for the service (2
5), and when the operating means (25) is operated, the opening degree of the electric expansion valve (3) is changed to an opening value different from the current opening value, giving priority to the opening degree controlling means (23). an opening degree changing means (30), and a change display means (31) for detecting and displaying a change in the state quantity of the refrigerant due to a change in the opening degree of the electric expansion valve (3) caused by the opening degree changing means (30). The configuration is such that it is provided.

(Function) With the above configuration, in the present invention, during normal operation, the opening degree of the electric expansion valve (3) in the refrigerant circulation system (8) is controlled to increase or decrease according to the operating state by the opening degree control means (23). , good refrigeration takes place.

Now, when an operator such as a service person determines whether or not there is a failure in the electric expansion valve (3), the operating means (25) is first manually operated by the operator. As a result, the opening degree of the electric expansion valve (3) is forcibly changed and controlled by the opening degree changing means (30) to an opening degree value different from the current opening degree value. Then, when the electric expansion valve (30) is in a normal state with no failure,
As the valve opening changes, the state quantity (for example, temperature and pressure) of the refrigerant in the refrigerant circulation system (8) also changes, and the change in this state quantity is detected and displayed by the change display means (31). Then, the operator can easily determine that the electric expansion valve (3) is in a normal state by looking at the change in the state quantity of the refrigerant.

On the other hand, when the electric expansion valve (3) fails, the valve opening does not change even if the valve opening is controlled by the opening changing means (30), and the state quantity of the refrigerant does not change either.

As a result, the state quantity of the refrigerant displayed by the change display means (31) does not change, and the operator can easily determine that the electric expansion valve (3) has failed.

(Example) Hereinafter, an example of the present invention will be described based on the drawings from FIG. 2 onwards.

FIG. 2 shows an embodiment in which the present invention is applied to a separate air conditioner, in which the left side of the dashed-dotted line in the figure shows the outdoor unit (X), and the right side of the dashed-dotted line shows the indoor unit (Y).

In the figure, inside the outdoor unit (X) there is a compression tl (
1), a four-way switching valve (2), an expansion valve (3), an outdoor heat exchanger (4) having an outdoor fan (4a), and an accumulator (5). Further, the indoor unit (Y) is provided with an indoor heat exchanger (6) having an indoor ventilation fan (6a). Then, each carrier (1) in both the outdoor and indoor units (X) and (Y)
(6) are connected to each other through refrigerant pipes (7) so that the refrigerant can be circulated to form a refrigerant circulation system (8), and the expansion valve ( 3)
consists of an electric expansion valve whose opening degree can be electrically adjusted to increase or decrease. During indoor heating operation, the four-way switching valve (2) is switched as shown by the solid line in the figure to circulate the refrigerant as shown by the solid line arrow in the figure, thereby absorbing heat from the outside air in the outdoor heat exchanger (4). The indoor heat exchanger (6) radiates the heat into the indoor air to heat the room, while during cooling operation, the four-way selector valve (2) is switched as shown by the broken line in the figure to transfer the refrigerant to the broken line arrow in the figure. By circulating the heat in the manner described above, the exchange of heat is reversed to cool the room. still,
In Figure 2, (9) is an inverter that variably adjusts its capacity depending on the operating frequency of compression 1 (1), and (10) is a bypass pipe (11) that connects both sides of the electric expansion valve (3). A capillary tube equipped with an electric expansion valve (
This is to circulate the refrigerant while throttling it when the refrigerant is fully opened in step 3). Further, (12) is a solenoid valve that opens during heating operation to connect the refrigerant pipe (13) connecting the discharge side of the compressor (1) and the inlet side of the outdoor heat exchanger (4) during heating. The defrosting operation of the outdoor heat exchanger (4), which serves as an evaporator during heating operation, is performed in a normal cycle (heating operation cycle).

In addition, in Fig. 2, (15) is the refrigerant circulation system (8).
A temperature sensor serving as a state quantity detection means for detecting the discharge temperature T1 (state quantity of the refrigerant) of the refrigerant from the compressor (1) in the above-mentioned state, the refrigerant discharge temperature signal from the temperature sensor (15) It is input to a control device (16) that controls the electric expansion valve (3) and the inverter (9).

The control device (16) calculates the deviation between the indoor temperature and the room temperature set value (room temperature target value), and sets the frequency in the inverter (9) so that the capacity of the compressor (1) changes according to this temperature deviation. It has a function of outputting a signal to make the air conditioning load and air conditioning capacity approximately correspond to each other, and as shown in FIG.
It has a control board (20) on which a PU etc. are arranged, and the control board (20) outputs a control signal for controlling the rotation of the electric expansion valve (3) from the CPU, and outputs this i control signal. The electric expansion valve (3) is connected to the electric expansion valve (3) via multiple control wirings (21)...
) to control the increase/decrease of the valve opening.

The opening degree control of the electric expansion valve (3) is performed based on the refrigerant discharge temperature signal from the temperature sensor (15) in both cooling and heating operations. That is, first, the opening degree of the electric expansion valve (3) is adjusted in advance to a basic opening value that is slightly throttled to prevent wet operation according to the operating frequency of the compressor (1), and then When the region shifts to overheating operation, control is performed to increase the opening degree by a small amount at predetermined time intervals based on the refrigerant discharge temperature signal from the temperature sensor (15) when the refrigerant discharge temperature is in a high temperature state higher than the set value. I do. This control constitutes an opening degree control means (23) that controls the opening degree of the electric expansion valve (3).

As shown in FIG. 3, the electric expansion valve (
A shorting pin (25) is provided as an operating means to be operated as necessary when determining the presence or absence of a failure in step 3).

This shorting pin (25) is normally open, and when servicing is required, for example, you can short-circuit it by preparing a separate conductive member or by touching it with the tip of a screwdriver. do.

The short circuit or open state of the short circuit pin (25) is input to CPtJ on the control board (20).

Next, the opening degree control of the electric expansion valve (3) will be explained based on the control flow shown in FIG. 4. Start, step S1
Determine whether the protection device of the compressor (1) has activated or not,
If the protective device does not operate (in the case of NO), it is determined in step S2 that the operation is normal, and the state of the shorting pin (25) is further determined in step S3. After controlling the opening degree of the electric expansion valve (3) to increase or decrease based on the refrigerant discharge temperature from the compressor (1) in S4, the process returns to Step S1.

On the other hand, when the short-circuit pin (25) is short-circuited (YES), that is, when it is necessary to determine whether or not there is a failure in the electric expansion valve (3), the opening degree of the electric expansion valve (3) is forcibly shown in Fig. 5. Thus, the opening degree is changed in 5 steps (0, 25, 50, 75, 100%) starting from the step near the current opening value, one step at a time every predetermined time (for example, 30 seconds) taking into account the response time of the refrigerant pressure. In order to control the opening value so that it returns to the original opening value after one round trip, in step S5, the value of the number of inspection operations N at the time of failure determination, which corresponds to the passage of one round trip of the opening change, is determined, and initially N=O.
Since the answer is NO, the valve opening degree is forcibly changed by one step every time the predetermined time period to elapses in step S6.

After that, in step S7, it is determined whether or not it is the end of the inspection operation in which the valve opening degree has been reciprocated once.If NO, the value of the number of inspection operations N is set to "0" value in step S8. Then, return to step S1 above and repeat the control to change the valve opening degree for each step, and after one round trip, the test operation is completed (YES).
Then, in step S9, the value of the number of inspection operations N is set to "1".
Set to value. Then, the process returns to step $1, and even if the short-circuit pin (25) is still in the short-circuit state, the number of inspection operations is N=1 in step S5, so the forced change control of the valve opening degree is performed. stops. Further, even if the shorting pin (25) is opened during one round trip in step S3, the forced change control is stopped at that point.

On the other hand, in the case of an abnormality (YES) in which the protection device of compression c (1) is activated in step S+, compression (1) is immediately stopped in step 31G.

Therefore, in the control flow of FIG. 4 above, step 8
3 to S9, when the short circuit pin (25) is short-circuited,
Prioritizing the opening degree of the electric expansion valve (3) over the opening degree control means (23), the opening degree is changed one step at a time every predetermined time to, the opening degree is made to reciprocate from fully open to fully open, and the shorting pin ( 25)
The opening degree changing means (30) is configured to control the opening degree to be changed to a value different from the opening degree value at the time of short circuit.

Therefore, in Figure 2 above, during cooling operation,
A short-circuit pin (2
5) A change display that detects and displays a change in the refrigerant pressure in the refrigerant pipe (7) (i.e., a change in the state amount of the refrigerant due to a forced opening change of the electric expansion valve (3)) during the short-circuit operation of step 5). A pressure gauge (31) as a means is attached and connected by an operator such as a service person.

Therefore, in the above embodiment, during normal operation,
The opening degree of the electric expansion valve (3) in the refrigerant circulation system (8) is first adjusted to a basic value corresponding to the operating frequency of the compressor (1), and then the opening degree control means (23) controls the compressor (1). )
Since the increase is controlled in accordance with the refrigerant discharge temperature from the compressor (1), overheating of the compressor (1) is reliably prevented and comfortable indoor air conditioning is performed.

On the other hand, during a test run of a refrigeration system or when a failure occurs, service personnel use the electric expansion valve (
3) is performed to check and determine whether there is a failure. In this case, the short-circuiting pin (25) on the control board (20) is operated to short-circuit by an operator such as a service person. At that time, as mentioned above, a pressure gauge (
31) are installed and connected by the operator. Based on the short-circuit operation of the short-circuiting pin (25), the opening degree of the electric expansion valve (3) is forcibly changed and controlled by the opening degree changing means (30). As shown in the figure, the opening degree is controlled step by step to a fully open state of 100%, and then gradually decreased to a fully open state of 0%.
The opening degree increases again in stages and returns to the original opening value. As a result, the low pressure on the suction side of the compressor (1) increases when the opening of the electric expansion valve (3) increases, and decreases when the opening decreases. On the other hand, when the electric expansion valve (3) fails, it remains locked and does not change even with the above-mentioned forced change control of the valve opening, and there is no change in the low pressure. As a result, the low pressure Changes in pressure are detected and displayed by a pressure gauge (31). Therefore, the operator should check this pressure gauge (31)
By looking at the change in the low pressure caused by this, it is possible to easily determine whether or not there is a failure in the electric expansion valve (3).

Incidentally, in the above embodiment, the operating means is constituted by the shorting pin (25), but it goes without saying that it may be constituted by a push button or the like. Furthermore, instead of controlling the refrigerant discharge temperature, the opening control means (23) may be configured to control the degree of superheating or the like.

In addition to low pressure, the objects of refrigerant state detection include
Various factors can be considered, such as evaporation temperature, compressor intake gas temperature, high pressure, condensation temperature, and discharge gas temperature, but it is best to detect low pressure that corresponds well to changes due to increases and decreases in the opening of the electric expansion valve. preferable.

Further, in the above embodiment, the opening degree of the electric expansion valve (3) is made to reciprocate one step at a time by the opening degree changing means (30) when the shorting pin (25) is short-circuited. The opening may be controlled directly to a predetermined opening, and in short, the opening may be controlled to a different opening from the opening during the short-circuit operation. Furthermore, the change display means (31) may be attached in advance instead of being attached and connected by the operator during the short circuit operation.

In addition, the pressure gauge (31) was installed at the gas side closing valve (17) of the refrigerant pipe (7) through which low-pressure gas refrigerant flows during cooling operation as described above, but during heating operation, low-pressure gas refrigerant flows through the gas side closing valve (17). A service port (
18), and a pressure gauge (18) is installed on the service boat (18).
31) may be connected. Alternatively, a service boat (19) may be provided in the refrigerant pipe (7), which has a low pressure during both cooling and heating operations, and a pressure gauge (31) may be connected to the service port (19).

Roughly speaking, in the above embodiment, the case where the present invention is applied to a separate type air conditioner has been described, but it goes without saying that the present invention can be similarly applied to an integrated type or other refrigeration equipment.

(Effects of the Invention) As explained above, according to the present invention, when determining whether or not there is a failure in the electric expansion valve, the valve opening is forced to be different from the opening value at that time based on the manual operation of the operating means. Since the change in the opening value is controlled and the change in the refrigerant state quantity accompanying the change in opening is displayed on the change display means, operators such as service personnel can easily determine whether or not there is a failure in the electric expansion valve. be able to.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention. Figures 2 to 5 show embodiments of the present invention, Figure 2 is a refrigerant piping system diagram applied to a separate air conditioner, and Figure 3 is a diagram showing the connection state between the control board and the electric expansion valve. , FIG. 4 is a flowchart showing the control flow of the electric expansion valve, and FIG. 5 is a diagram showing how the opening degree of the electric expansion valve changes when the shorting pin is short-circuited. (3)...Electric expansion valve, (8)...Refrigerant circulation system,
(23)...Opening degree control means, (25)...Short pin, (30)...Opening degree changing means, (31)...Pressure gauge. Patent applicant Daikin Industries, Ltd. Figure 5 # Figure 4

Claims (1)

[Claims] (1) Electric expansion valve (3) located in the refrigerant circulation system (8)
) and an opening degree control means (23) for controlling the opening degree of the electric expansion valve (3) according to the operating state, the refrigeration system comprising: a service operating means (25);
Opening degree changing means (30) for controlling the opening degree of the electric expansion valve (3) to be changed to a different opening value from the current opening value, giving priority to the opening degree controlling means (23) when the above-mentioned electric expansion valve (3) is operated. and a change display means (31) for detecting and displaying a change in the state quantity of the refrigerant due to a change in the opening degree of the electric expansion valve (3) by the opening degree changing means (30). Failure detection device for electric expansion valves in equipment.