JPH03186156A - Air conditioner pressure equalization device - Google Patents

Abstract

PURPOSE:To prevent an abnormal shutdown of a compressor of an air conditioner by a method wherein a bypass line remains open even when a period, for which the compressor is prohibited to restart, has elapsed after the compressor is shut down, and the compressor is started after the bypass line which has been closed is opened. CONSTITUTION:A compressor 1 is prohibited to start for a period a first set time period elapses after the compressor 1 is shut down by a controller 6, and a bypass line 42 is kept open until a second set time period elapses. When the second set time period is set at a time period during which the difference between the high and low pressures of the compressor 1 is satisfactorily equalized, and the compressor 1 is restarted, the compressor 1 starts with a little difference between the high and low pressures. And, when the second set time period has passed and a start request signal of the compressor 1 is input after the bypass line 42 is closed, the compressor 1 is started after an on-off valve 42a is opened for a specified time period. Thereby, the compressor 1 can be continuously operated without an abnormal shutdown.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pressure equalizing device that equalizes high and low pressures in an air conditioner to facilitate restarting the compressor after it is stopped.

(Prior art) In an air conditioner, if the compressor is restarted immediately after being stopped, the pressure difference between the discharge side gas pressure (high pressure) and the suction side gas pressure (low pressure) of the compressor is large, so the compression Excessive current may flow through the machine's motor, triggering its protection device. In particular, in an inverter-driven compressor, an instantaneous overcurrent causes a trip, and subsequent continuous operation is no longer possible.

For this reason, conventionally, in Japanese Utility Model Application Publication No. 53-162453, the discharge side and the suction side of the compressor are connected by a bypass passage, and when the compressor is stopped, the bypass passage is opened, and thereby the high and low pressures of the compressor are connected. It has been proposed to reduce the pressure difference between Furthermore, in the method disclosed in Japanese Utility Model Application Publication No. 56-149841, restarting the compressor is prohibited for a certain period of time from the time when the compressor is stopped, and a restart waiting period is set.
During this time, the difference between high and low pressures in the compressor is reduced.

(Problem to be Solved by the Invention) By the way, when opening the bypass path as in the above-mentioned conventional method, if it is left open 17, the liquid refrigerant stagnant in the condenser etc. on the high pressure side will flow into the suction circuit. There is a risk that this movement may cause a so-called liquid back up when the compressor is restarted, and for this reason, the bypass path is opened only during the restart standby period of the compressor.

However, if the bypass path is opened in the limit 17 while the compressor is waiting for restart, when the bypass path is closed after the restart standby period has elapsed, the compressor The difference between high and low pressures may become large. For example, when the outside air temperature is low in the heating operation mode, the indoor temperature is high, so evaporation of the refrigerant occurs in the indoor heat exchanger, resulting in a rise in high pressure. Conversely, when the outside air temperature is high in the cooling operation mode, the refrigerant condenses in the indoor heat exchanger and is pulled by it, lowering the low pressure, thereby increasing the high-low pressure difference. At this time,
Since the compressor is started with a high differential pressure, there is a problem that continuous operation of the compressor becomes impossible.

The present invention has been made in view of the above points, and its purpose is to reduce the difference between high and low pressures when restarting the compressor by controlling the above-mentioned restrictions on restarting the compressor and opening and closing of the bypass passage. The objective is to ensure that the compressor can be continuously operated without abnormally stopping the compressor.

(Means for Solving the Problems) To achieve a distant relative of the second object, in the invention according to claim (1), the bypass path is opened until a certain period of time has elapsed after the compressor was stopped. Further, when the bypass path is once closed after that, if there is a request to start the compressor, the bypass path is first opened, and then the compressor is started after a predetermined period of time has elapsed.

Specifically, in this invention, as shown in FIG. 1, a compressor (1) and an outdoor heat exchanger (2a) are used.

(2b), pressure reduction mechanism (25a), (25b).

(51) and the indoor heat exchanger (5) are connected to a closed circuit [7
For an air conditioner equipped with a refrigerant circuit (3), a bypass path (
42) and opening/closing means (42) for opening and closing this bypass path (42).

After the compressor (1) is stopped, the first set time (T1)
The opening/closing means (42) is opened until a second set time (T2) longer than the first set time (Tl) has elapsed, and the compressor When the second set time (T2) has elapsed from the stop of (1), the opening/closing means (42) is closed.
) After the closing operation of the compressor (1), when a starting request signal for the compressor (1) is manually inputted, the control means (42) is controlled to open the opening/closing means (42) for a predetermined period and then start the compressor (1).
6).

In addition, in the invention according to claim (a), since the amount of refrigerant is large, the air conditioner can be expected to have a particularly effective effect and has the following configuration. That is, the air conditioner has the following configuration. and a plurality of heat source side heat exchangers (2a), one end of which is switchably connected to the discharge side and suction side of the compressor (1), and which are provided in parallel.

(2b) and the heat source side heat exchanger (2a), (2b)
A plurality of heat source side pressure reduction mechanisms (25a) provided corresponding to each of the heat source side pressure reduction mechanisms (25a) capable of adjusting the pressure reduction and flow rate of the refrigerant.

(25b), a user-side heat exchanger "5 (5) whose one end is switchably connected to the discharge side and suction side of the compressor (1), and the user-side heat exchanger (5), respectively. established as
User-side pressure reduction mechanism (51) capable of adjusting refrigerant pressure reduction and flow rate
and a switching mechanism (21a) that switches the refrigerant flow direction so that the user-side heat exchanger (5) becomes an evaporator or a condenser.
), (21b).

(Function) With the above configuration, in the invention according to claim (1), the control means (6) controls the compressor (1) from the time when the compressor (1) stops until the first set time (T+) elapses. machine (1
) is prohibited from starting. Further, until the second set time (T2) elapses, the opening/closing means (42) is opened and the bypass path (42) is opened. Part 1. Then, the second set time (T2) is set to a time in which the pressure difference between the high and low pressures of the compressor (1) is sufficiently equalized.1. If you do so, when you restart the compressor (1), the difference between high and low pressures at that point is small, so the compressor (1)
) can be started without high differential pressure conditions.

Further, after the second set time (T2) has elapsed, the opening/closing means (42
a) is closed to close the bypass passage (42), but after this closure, the start request signal for the compressor (1) is transmitted to the control means (6).
When the compressor (1) is manually operated, the opening/closing means (42) is opened for a predetermined period of time, and then the compressor (1) is started. For this reason,
Since the bypass passage (42) is opened when the compressor (1) is started, the difference between high and low pressures is kept low, and therefore the compressor (1) can be started with a low differential pressure ε.

In the invention according to claim (2), the air conditioner has a plurality of heat source side heat exchangers (2a) and (2b),
This type has long piping and a large amount of refrigerant, so the compressor (
1) The liquid back up is noticeable when the air conditioner is stopped, and the above effects can be effectively obtained by applying this to an air conditioner.

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

FIG. 2 shows an air conditioner (X) according to an embodiment of the present invention, and this air conditioner (X) has multiple indoor units (three in the figure) for one outdoor unit (A). (B),
(B) This is a multi-type air conditioner in which . . . are connected in parallel.

The outdoor unit (A) includes a compressor (1) and two outdoor heat exchangers (2a) (2b) which are heat exchangers on the heat source side. The compressor (1) includes a first compressor (1a) whose capacity is adjusted by an inverter (not shown) whose output frequency can be variably switched, and an unloader (not shown) which operates differentially depending on the pilot pressure. The capacity is fully loaded (for example 100%) and unloaded! ! 3(
The second compressor (lb) is adjusted in two stages (50%)
This is a variable capacity type in which the first and second compressors (la) are connected in parallel via a check valve (1c).
, (lb) are each equipped with a compressor (la) on the discharge side.
First and second oil separators (1d) and (1e) are installed to separate the oil in the gas discharged from the compressors (la) and (ih), respectively, and return it to the suction side of the compressors (la) and (ih). ing.

The high pressure gas line (31) of the refrigerant circuit (3) is connected to the discharge side of the compressor (1), and the low pressure gas line (31) is connected to the suction side of the compressor (1).
32) are connected to each other.

Further, each of the outdoor heat exchangers (2a) and (2b) is installed in parallel with the compressor (1), and one end of each of the outdoor heat exchangers (2a) and (2b) is connected to a four-way Gas pipe (22a) equipped with switching valves (21a) and (21b)
), (22))) to the high pressure gas line (3
1) and the low pressure gas line (32), while each outdoor heat exchanger (2a), (2b)
At the other end is a liquid pipe (33a) of a liquid line (33) in the refrigerant circuit (3).

(33b) is connected. Each of the four-way switching valves (21a) and (21b) is connected to each outdoor heat exchange rA (2
When a) and (2b) function as condensers, the solid line in the figure switches so that the gas pipes (22a) and (22b) communicate with the high-pressure gas line (31), while on the other hand, the lines outside each outdoor When the heat exchangers (2a) and (2b) function as evaporators, the gas pipes (22a) and (22b) are switched to the broken lines in the figure so that they communicate with the low pressure gas line (32). Also, the four-way switching valve (21a).

One boat of (21b) each has a capillary (23
a), (23b) connecting pipes (24a) (24
b) via a four-way switching valve (21a).

(2lb) and the low pressure gas line (32) are connected to the gas pipes (22a) and (22b).

Furthermore, the high pressure gas line (31) is provided with a gas pipe (22).
a), a one-way valve (4) on the downstream side (on the indoor unit (B) side) of the connection part of (22b).

(4), and the low pressure gas line (32) has a gas pipe (2).
2a) and (22b) on the downstream side (compressor (1)
) side) are provided with accumulators (41), respectively. In addition, a high pressure gas line (31) on the upstream side of the connection part of the gas pipes (22a) (22b) and a gas pipe (22b) are connected to each other.
2a), the low pressure gas line (22b) downstream of the connection part and upstream of the accumulator (41)
32), in other words, the discharge side and suction side of the compressor 0) are connected by a pressure equalizing bypass path (42). This pressure equalization bypass path (42) includes an on-off valve (42a) as an on-off means and a flow rate adjustment capillary (42b).
) are provided.

In addition, each liquid pipe (33a) in the liquid line (33)
, (33b) are connected to a receiver (43) so that their respective liquid refrigerants merge with each other, and a main liquid pipe (33c) of the liquid line (33) is connected to the receiver (43). Further, each of the liquid pipes (33a) and (33b) is provided with an outdoor electric expansion valve (25a) and (25
b) are respectively arranged, and this outdoor electric expansion valve (
25a), (25b) are outdoor heat exchangers (2a) (
2b) reduces the pressure of the liquid refrigerant when functioning as an evaporator, and adjusts the flow rate of the liquid refrigerant when functioning as a condenser.

Between the downstream side of the one-way valve (4) in the high-pressure gas line (31), which is the discharge side of the compressor (1), and the receiver (43), so-called hot gas, which is a high-pressure gas refrigerant, is sent to the receiver (43). The hot gas bypass line (45) is connected by a hot gas bypass line (45) that is equipped with a hot gas on-off valve (45a) and a capillary (45b) that adjusts the flow rate of the hot gas.

On the other hand, the high pressure gas line (31) and the low pressure gas line (
32) and the main liquid pipe (33) are each extended indoors, and the high pressure gas line (31) is connected to a high pressure branch pipe (31b) via a flow divider (31a).

(31b), ..., and the low pressure gas line (32) is connected to the low pressure branch pipe (32b) (32) via the flow divider (32a).
b),... In addition, the main liquid pipe (33) is connected to a flow divider (
33d) via liquid branch pipe (33e).

(33e), . . . and these branch pipes (31b), (32b), (33e) are connected to each indoor unit (B), (B), .

The above-mentioned indoor units (B), (B), ... have the same configuration, and each has an indoor heat exchanger (
5) and an indoor electric expansion valve (51) which is a user-side pressure reducing mechanism. The indoor electric expansion valve (51) is disposed in the liquid branch pipe (33e), and this liquid branch pipe (33e) is connected to one end of the indoor heat exchanger (5). The other end of 5) is connected to the high pressure branch pipe (31b) and low pressure branch pipe (32b) via the gas pipe (5a). Then, a high pressure branch pipe (31b) and a low pressure branch pipe (
32b) is provided with an on-off valve (
52) and (53) are provided, and both on-off valves (52) and (53) are provided.
2), (53) to open and close the indoor heat exchanger (53).
) to high pressure gas line (31) and low pressure gas line (32)
When the indoor heat exchanger (5) functions as an evaporator (for cooling), the low-pressure side on-off valve (53) is connected, and when the indoor heat exchanger (5) functions as a condenser (for heating), the high-pressure side on-off valve (53) is connected. (52)
It is configured to open each.

Furthermore, the liquid branch pipe (33e) of the indoor unit (B)
and the downstream side of the on-off valve (53) in the low-pressure branch pipe (32b) are connected by a low-pressure bypass path (54), and a bypass valve (54a) and a capillary (54b) are connected to this low-pressure bypass path (54). It is arranged. Furthermore, a piping heat exchanger (54c) is formed between the low-pressure bypass path (54) and the liquid branch pipe (33e), and the branch refrigerant flowing out from the indoor heat exchanger (5) during heating is flashed. configured to prevent flow. Further, a capillary (55) for flow rate adjustment is connected between the upstream side of the on-off valve (52) in the high-pressure branch pipe (3l b) and the gas pipe (5a).
a), and is configured to bypass condensate that accumulates in the high-pressure branch pipe (3lb) and the like during cooling. The on-off valves (52) (53) and both bypass paths (54), (
55) are integrally stored in the kit (56), and include a compressor (1), an outdoor heat exchanger (2a), (2b),
The indoor heat exchangers (5), (5), ... are connected by a high pressure gas line (31), a low pressure gas line (32) and a liquid line (33) to form a refrigerant circuit (3). .

In addition, (26) is the outdoor heat exchanger (2a), (2b)
(44) is a suction heat exchanger that exchanges heat between the low pressure gas line (32) and the main liquid pipe (33c). (57) is an indoor fan placed close to the indoor heat exchanger (5).

Furthermore, various sensors are arranged in the refrigerant circuit (3). That is, (T hl) is the indoor unit (B
), (T h2) is a gas temperature sensor that detects the gas refrigerant temperature of indoor unit CB), (T h3) is a room temperature sensor that detects the temperature of the air sucked into the indoor fan (57). It is a sensor. (Th4) is the outdoor heat exchanger (2a), (2b) is the liquid temperature sensor that detects the liquid refrigerant temperature on the side, (Th5) is the outdoor heat exchanger (2a)
, (2b) is a gas temperature sensor that detects the discharge gas refrigerant temperature, (The he) is an outside temperature sensor that detects the outside air temperature, and (Th7) is a discharge gas sensor that detects the discharge gas refrigerant temperature of the compressor (1). The temperature sensor (HPS) is a high pressure sensor (LPS) that detects the discharge gas refrigerant pressure of the compressor (1).
) is a low-pressure pressure sensor that detects the suction gas refrigerant pressure of the compressor (1).

And (6) is a control device with a built-in CPU that controls the operation of each device in the above refrigerant circuit (3), and here, the on-off valve (42) in the pressure equalization bypass path (42) is
The explanation will be limited to the pressure equalization control and compressor (1) operation control for a). In this control device (6), the on-off valve (4
2a) and the compressor (1) are performed according to the flowchart shown in FIG. That is, first, in step S1, timer 1 is set to 10 minutes, and timer 2 is set to 10 minutes.
are set for 3 minutes each. Timer 1 is compressed J!
Timer 2 is used to set the second set time (T2) for opening the on-off valve (42a) and opening the pressure equalization bypass path (42) from the stop of compressor (1). A first set time (
T1). Next, in step S2, the on-off valve (42a) is turned ON to open the valve, the compressor (1) is stopped, and the timer 1.degree.2 is counted. After this, in step S3, the timer 2
Determine whether or not the time has expired, and check the NO during counting.
When this happens, step S2.33 is repeated. If the determination becomes YES due to the time up of timer 2, step S
4, the on-off valve (42g) is kept open, the compressor (1) is kept stopped, and the timer 1 is counted. In step S5, the room temperature sensor (Th
It is determined whether there is a request to start the compressor (1) by turning on the thermometer in step 3), and if this determination is NO, "no start request".
In this case, it is determined in step S6 whether or not timer l has timed up, and if the determination is No, step S6 is performed.
Return to 4. On the other hand, the determination in step S6 above is based on timer 1.
If the answer is YES due to time-up, in step S7 the on-off valve (42a) is turned OFF and closed, the compressor (1) is kept stopped, and in the next step Sδ, the thermostat is turned on again to turn the compressor (1) off. Determine whether there is a start request. If this determination is NO for "starting with sushi", step S7. While repeating S8, if the determination is YES based on the "start request", the timer 4 is set to 10 seconds in step S9. This timer 4 is activated when the compressor (
This is to avoid the difference in high and low pressures in case 1) remains. After this step S9, step S1o
The on-off valve (42a) is turned ON to open the valve, the compressor (1) is kept stopped, and the timer 4 is started to count. Next, in step Sl+, the compressor (1
), and if this determination is YES for LJ that is a startup request, the process returns to the first step S1, but if the determination is NO due to ``starting request exists'', the timer 4 is set in step 512. Set the time up to 11, and if the time up is not up, step SIG”S
12 is repeated, and when the time is up, step S5 is executed as well as when the determination in step S5 is YES.
Proceed to I3 and set timer 3 to 11 minutes. This timer 3 is used to set the time for opening the bypass path (42) when the compressor (1) is started, and is used in step S13.
After that, in step SX, the on-off valve (42a) is turned ON to open the valve, the compressor (1) is started, and the timer 3 is counted. Then, step S
In step I5, it is determined whether there is a request to start the compressor (1), and if the determination is YES (no startup request), the process returns to the first step S+, but if the determination is NO due to "start request 6". In step S16, it is determined whether or not the timer 3 has timed up. If there is no timed up, the process returns to step SI4. If the timed up has occurred, the process proceeds to step S17, in which the on-off valve (42a) is turned OFF to close it, and the compressor (1) is turned off. start.

In the next step s+8, it is determined whether or not there is a request to start the compressor (1), and when this determination is NO (starting request is made), step SI7. While repeating SI8, Y
When it is ES, the process returns to the first step S1.

Therefore, in this embodiment, according to the flow in the control device (6), after the compressor (1) is stopped, the compression 1 is continued until the first set time (T1) set by the timer 2 elapses.
fi (1), and opens the opening/closing means until a second set time (T2) set by timer 1 and longer than the first set time (T1) elapses, and the compressor ( The second set time (T2) from the stop of step 1)
), the on-off valve (42a) is closed and the on-off valve (42a) is closed.
After the closing operation of step 2a), when a start request signal for the compressor (1) is input, the on-off valve (42a) is opened for a predetermined period of time set by the timer 4, and then the compressor (1) is started. It is composed of

Next, the air conditioning operation of this air conditioner (X) will be explained.

First, when operating each indoor unit (B), (B), etc. for cooling, both four-way switching valves (
21a) and (21b) are switched to the solid lines in FIG. 2, and the gas pipes (22a) and (22b) are communicated with the high pressure gas line (31). In addition, each indoor unit) (B),
In (B),..., the high pressure side on-off valve (52) closes,
Also, the low pressure side on-off valve (53) is opened, and the gas pipe (5a) is communicated with the low pressure branch pipe (32b). In this state, the high-pressure gas refrigerant discharged from the compressor (1) is delivered to each outdoor heat exchanger (2a).

(2b) and condenses, and this condensed liquid refrigerant passes through the liquid line (33) to each indoor unit (B).

(B) Flows to the indoor electric expansion valve (51).

After expanding in (51),..., each indoor heat exchanger (5
), (5),... and is evaporated in the low pressure gas line (3
2) and returns to the compressor (1).

On the other hand, each of the above indoor units (B), (B),...
When operating a heating system, the refrigerant flows in the opposite direction to that during cooling.

In other words, the four-way switching valve (21a) of the outdoor unit (A),
(21b) is switched to the broken line in Fig. 2, and in each indoor unit (B), (B),...
2) is opened, and the low pressure side on-off valve (53) is closed, and the refrigerant from the high pressure gas line (31) is transferred to the indoor heat exchanger (5).
After condensing, it flows through the liquid line (33) and expands at the outdoor electric expansion valves (25a) and (25b), and is transferred to the outdoor heat exchanger (2
a).

(2b)]7 and returns to the compressor (1).

During the cooling operation, for example, switching the opening/closing states of both on-off valves (52) and (53) in one indoor unit (B) will result in heating operation, and conversely, during the above-mentioned full heating operation, for example, one Both on-off valves (52) in the indoor unit (B).

When (53) is switched, cooling operation is started, and thus so-called simultaneous heating and cooling operation is performed. At that time, for example, if two of all the indoor units (B), (B), ... are operated in heating mode and the remaining one is operated in cooling mode, then indoor units (B), (B) in heating mode are operated. ) The liquid refrigerant flowing out from the liquid line (33) merges at the flow divider (33d), flows to the indoor unit (B) for cooling operation, evaporates, and flows into the compressor (1) via the low-pressure gas line (32). I will be going back.

During this same amount of cooling and heating operation, the two outdoor heat exchangers (
2a) and (2b) operate as an evaporator or a condenser depending on the indoor load, and furthermore, one unit is operated and the other unit is stopped.

During operation of such an air conditioner (X), for example, the room temperature sensors (
Th3), (Th3), ... are thermo OF
In some cases, the compressor (1) is stopped, and FIG. 4 shows the change in refrigerant pressure on the discharge side and suction side of the compressor (1) at that time. That is, when the compressor (1) is stopped, at the same time, the on-off valve (42a) is opened to open the pressure equalization bypass passage (42), and at the same time, the control device (
6) Timer 1 and Timer 2 start counting, and Timer 2 is counting.

In other words, restarting the compressor (1) is prohibited until three minutes have elapsed since the compressor (1) stopped.

Also, by opening the bypass path (42), the compressor (1
) becomes smaller. After timer 2 times up, until timer 1 times up (compressor
The on-off valve (42a) is kept open until 10 minutes have passed from the stop of step 1), so that the pressure difference between the high and low pressures of the compressor (1) is sufficiently equalized. During this time, the compressor (1) is started immediately upon receiving the restart request signal. then,
Since the pressure difference between the high and low pressures of the compressor (1) is sufficiently low, the compressor (1)
) can be started without high differential pressure conditions.

When the timer 1 times up after 10 minutes have elapsed since the compressor (1) stopped, the on-off valve (42a) is closed and the bypass path (42) is closed. When the on-off valve (42a) is closed once in this way, when there is a restart request signal for compression [(1), first, the timer 4
The on-off valve (42a) opens for 10 seconds set by , the bypass passage (42) is opened, and then the compressor (
1) is started. Therefore, the compressor (
Even if the high-low pressure difference in 1) increases slightly, it is reduced by opening the on-off valve (42a), and the compressor (1) can be started with a low differential pressure.

Simultaneously with the start of the compressor (1), the timer 3 starts counting, and while the timer 3 is counting, the on-off valve (
42a) is held open, but after one minute set by the timer 3 has elapsed, the on-off valve (42a) closes.

Therefore, in this embodiment, since the pressure on the discharge side and the suction side can be reliably maintained at equal pressure when the compressor (1) is started, the compressor (1) can be operated continuously without abnormally stopping. Its reliability can be improved.

In addition, if frost occurs in both the outdoor heat exchangers (2a) and (2b), the compartment outer heat exchanger (2a)
) and (2b) are used as a condenser and the other as an evaporator to perform defrost operation. In other words, all the indoor electric expansion valves (51), (51), ... are closed, and the high-pressure gas refrigerant flows from the high-pressure gas line (3]) to one of the outdoor heat exchangers (2a or 2b) and is condensed. let me,
This condensed liquid refrigerant flows from the receiver (43) to the other liquid pipe (33b or 33a), and the outdoor electric expansion valve (25b
Or after expanding in 25a), the other outdoor heat exchanger (
2b or 2a) and returned to the compressor (1) via the low pressure gas line (32). This operation is performed alternately in both the outdoor heat exchangers (2a) and (2b), thereby defrosting both the outdoor heat exchangers (2a) and (2b). According to this defrost operation, the indoor unit (B),
(B), . . . no cold draft occurs, and there is no need to stop the indoor fan (57).

In this example, the outdoor unit (A) and the indoor unit (B) were connected by three pipes: a high-pressure gas line (31), a low-pressure gas line (32), and a liquid line (33). It may be connected to the line using two pipes.

Further, three or more outdoor heat exchangers (2a) and (2b) may be provided, and one indoor unit CB) may be provided.

(Effect of the invention) As explained above, according to the invention according to claim (1), after the compressor of an air conditioner is stopped, the bypass path is kept open even after the restart prohibition time has passed, and the bypass path When the compressor is closed, when there is a compressor start signal, the bypass path is opened and then the compressor is started.When the compressor is restarted, the difference between high and low pressures is reliably reduced and the compressor is restarted. It can be operated continuously without abnormal stoppage.

In addition, according to the invention according to claim '2J, the air conditioner has a plurality of heat source-side heat exchangers that cause a significant liquid backlash when the compressor is stopped, so that the above effects can be made even more effective. can be obtained.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of the present invention. Figure 2 and the following drawings show embodiments of the present invention. Figure 2 is a refrigerant circuit diagram showing the overall configuration of an air conditioner, Figure 3 is a flowchart diagram showing the control procedure in the control device, and Figure 4 is FIG. 3 is a characteristic diagram showing changes in high and low pressures due to the stoppage of the compressor. (X)...Air conditioner (A)...Outdoor unit (B)...Indoor unit (1)...Compressor (2a), (2b)...Outdoor heat exchanger (heat source side heat exchanger) (3)...refrigerant circuit (5)...indoor heat exchanger (user side heat exchanger) (6)...control means (21a), (21b) = four paths Switching valve (switching mechanism) (25a), (25b) - Outdoor electric expansion valve (heat source side pressure reducing mechanism) (42)...Bypass path (42a)...Opening/closing valve (opening/closing means) (51)... Indoor electric expansion valve (user side pressure reduction mechanism) (T
1)...First set time (T2)...Second set time Fig. 4 (X)...Air conditioner (A)...Outdoor unit, (B)...Indoor Unit (1)...Compressor (2a), (2b)...Outdoor heat exchanger (heat source side heat exchanger) (3)...Refrigerant circuit (5)...Indoor heat exchanger (Using side heat exchanger) (6)... Control means (21a), (21b) - Four-way switching valve (switching mechanism) (25a), (25b) - Outdoor electric expansion valve (heat source side pressure reducing mechanism) ( 42)...Bypass path (42a)...Opening/closing valve (opening/closing means) (51)...Indoor electric expansion valve (user side pressure reducing mechanism) (T
1)...First set time (T2)...Second set time Figure

Claims (2)

[Claims] (1) Compressor (1), outdoor heat exchanger (2a), (2b
), a refrigerant circuit (
3), a bypass passage (42) connecting the discharge side of the compressor (1) to the suction side, and an opening/closing means (42a) for opening and closing the bypass passage (42).
After the compressor (1) is stopped, the start of the compressor (1) is regulated until a first set time (T_1) has elapsed, and a second set time (T_2) is set longer than the first set time (T_1). ) is opened until the second set time (T_2) has elapsed, the opening/closing means (42a) is opened until the second set time (T_2) has elapsed.
42a), and after the closing operation of the opening/closing means (42a), when a start request signal for the compressor (1) is input, the opening/closing means (42a) is opened for a predetermined time, and then the compressor (1) is closed.
1. A pressure equalizing device for an air conditioner, comprising: a control means (6) for controlling the start of the air conditioner. (2) The air conditioner consists of a compressor (1) and one end connected to the compressor (
The heat source side heat exchangers (2a), (2b) which are switchably connected to the discharge side and the suction side of 1) and are provided in parallel, and the heat source side heat exchangers (2a), (2b). A plurality of heat source side pressure reducing mechanisms (25a) and (25b) are provided correspondingly to each other and are capable of reducing the pressure and adjusting the flow rate of the refrigerant, and one end is switchably connected to the discharge side and suction side of the compressor (1). a user-side heat exchanger (5), which is provided in correspondence with each of the user-side heat exchangers (5), and a user-side pressure reduction mechanism (51) that is capable of reducing the pressure and adjusting the flow rate of the refrigerant; The air conditioner is equipped with a refrigerant circuit (3) equipped with switching mechanisms (21a) and (21b) that switch the refrigerant flow direction so that the heat exchanger (5) functions as an evaporator or a condenser. The pressure equalization device for an air conditioner according to claim (1), characterized in that: