JPS5914704B2 - Refrigeration circuit of multi-room air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a so-called multi-room air conditioner in which a plurality of indoor units are connected to one outdoor unit. This is one of its purposes.

In a conventional multi-room air conditioner, when the indoor unit is in heating operation with the compressor running,
When adding another indoor unit for heating operation, the gas-side solenoid valve and source-side solenoid valve that control the flow of refrigerant to the indoor heat exchanger of the indoor unit that is being operated for additional heating are opened at the same time. .

However, in the indoor heat exchanger of the indoor unit that was subjected to this additional heating operation, the gas side solenoid valve and the source side solenoid valve were closed before the heating operation was started, and the flow of refrigerant was stopped. Since it was connected to a low-pressure circuit, the pressure was almost the same as the suction pressure of the compressor.

Therefore, if the gas side solenoid valve and the source side solenoid valve are opened at the same time, high pressure gas will flow into the low pressure indoor heat exchanger at high speed, and this flowing refrigerant will generate a loud impact noise and cause the gas side solenoid valve to open. By rapidly moving the pilot valve part of the valve, a clicking sound may be generated.

These impact noises and lunchbox noises are amplified by the indoor unit, creating a serious problem in that they generate large noises and vibrations from the floor and walls on which the indoor unit is installed.

Further, these drawbacks similarly occur even when only the source-side solenoid valve is opened in the same state.

The present invention is intended to eliminate the above-mentioned drawbacks, and seven embodiments thereof will be described below with reference to the drawings.

FIG. 1 is a refrigeration cycle diagram of an embodiment of a multi-chamber air conditioner according to the present invention. 6,
Several branch pipes 7 formed by branching several main pipes 6 at branch points 13
a, 7 b) 7 c, these several branches 7 a s
The same number of gas side branch pipes 8a and 8 as 7 b s 7 c
b, 8c, these gas side branch pipes 8a.

A gas side main pipe 9 made by collecting 8b and 8c, an accumulator 10, several heating throttling mechanisms 11 provided in the main pipe 6, and a heating throttling mechanism 11 in parallel to control the flow of refrigerant during heating operation. A check valve 12 provided on the blocking side, several heating throttle mechanisms 11 of the main pipe 6, and several branch pipes 7a, 7b, 7c.
A liquid receiver 14 is provided between the branch part 13 and the branch pipe 7.
a 27 b bidirectional aperture mechanism 22 during s7c
a s 22 b.

A two-way solenoid valve 15a is provided in series with 22c.

15b, 15c, several branch pipes 7a between each electromagnetic valve 15a, 15b115c and the heating throttle mechanism 11.

7b, 7c, or several main pipes 6 and each indoor unit 30
a, 30b, 30c use side heat exchanger 31a.

31 b s 31 c and each gas side solenoid valve 21a, 2
1b.

Bypass pipes 23 a s 23 b s connecting gas side branch pipes 8 a , 8 b , and 8 c between 21 c
23 c.

A direct-acting type for bypass is provided in the bypass pipes 23a, 23b, 23c and is arranged to allow the flow of refrigerant toward the gas side branch pipes 8a, 8b, 8c when energized and to block it when energized. Solenoid valve 25a=25b*25c, this bypass solenoid valve 25 a s 25 b.

25c and the gas side branch pipes 8a, 8b, 8c in the bypass pipes 23a, 23b, 23c.
, 8b, 8c (check valves 26a * 26b, 26cm) Check valves 17 (provided in a direction that allows refrigerant to flow toward the low pressure circuit 20 side during heating operation)
a s 17 b z 17 c and apertures 18a, 18b
The solenoid valve 15 can be made by connecting the solenoid valves s18c and s18c in series, respectively.
a, 15b, 15c and each indoor unit 30a, 30b,
Bypass pipes 19 a, 19 b s connecting several branch pipes 7 a s 7 b ) 7 c and the low pressure circuit 20 during heating operation
19c, two-way flow solenoid valves 21a, 2 provided in the gas side branch pipes 8a, 8b, and ac, respectively.
1 b s 21 c.

Note that the outdoor unit 1 includes a blower in the heat source side heat exchanger 5.

Moreover, the indoor units 30a) 30b-30c are user-side heat exchangers 31a and 3lb, respectively.

31c, and an indoor blower that sends the air heat-exchanged by the user-side heat exchangers 31a, 31b, and 31c into the room.

Furthermore, the direct acting solenoid valve used here is constructed as shown in FIG.

2, the solenoid valve 25 includes an inlet pipe a, an outlet pipe, a valve body 50 whose position is fixed, a plunger 52 that is pulled up by an electromagnetic coil 51, a spring 53 that pushes down this plunger 52, etc. Cylindrical body 54 to accommodate
It is composed of the following operations.

Assuming that all the electromagnetic coils 51 are in a non-energized state, the cylindrical body 5
4 and the plunger 52, the pressure Pa inside the inlet pipe a and the cylinder body 54 and the plunger 52
The pressure P in the space created by the surface in contact with the spring 53
c are equal.

Then, if the area of the surface where the plunger 52 contacts the spring 53 is Ap, the cross-sectional area of the hole 55 of the valve body 50 is Av, the force of the spring 53 to push down the plunger 52 is Fs, and the weight of the plunger is Fp, The downward force F1 of the plunger 52 is F1=F s 1 Fp +A
v P a.

On the other hand, a force F trying to push the plunger 52 upward
2 is F22 Avpb if the pressure inside the outlet pipe is pb
becomes.

Therefore, the relationship between pressures Pa and pb is Pa>Pb
In this case, the relationship between F and F2 is Fl>F2, so the plunger 52 is pushed downward with a strong force, and the hole 55 of the valve body 50 is blocked by the tip of the plunger 52, and the inlet is closed. Pipe a and the outlet pipe do not communicate with each other.

When the electromagnetic coil 51 is energized from this state, the plunger 52 is pulled up by the force Fc due to the magnetic force of the electromagnetic coil 51, so the relationship Fl + F2 + FC is established, the plunger 52 is pulled upward, and the hole 55 of the valve body 50 is pulled up. The inlet pipe a and the outlet pipe A are communicated with each other.

On the other hand, when the electromagnetic coil 51 is de-energized, the pressure inside the outlet pipe pb
is thicker than the pressure Pa in the inlet pipe a to some extent (then F
2>F occurs, the plunger 52 is pushed upward, and even if the electromagnetic coil 51 is de-energized, the flow from the outlet pipe to the inlet pipe a cannot be stopped.

In other words, it is possible to start and stop the flow in one direction, but there are many cases where the flow in the opposite direction cannot be stopped even if the flow is possible.

FIG. 3 shows an embodiment of the electric circuit of the multi-room air conditioner according to the present invention, showing the coil SvLa of the solenoid valve 15a and the electric EB valve 2.
The circuit in which the coil 5VGa of 1a and the relay contact 46a are connected in series and the electromagnetic switch MRa are respectively connected in parallel to the power supply 45 via the operation switch 40a of the indoor unit 30a, and similarly the coil 5VLb of the solenoid valve 15b. The circuit in which the coil 5VGb of the solenoid valve 21b and the relay contact 46b are connected in series, and the solenoid switch MRb are connected to the power supply 45 via the operation switch 40b of the indoor unit 30b.
Similarly, the coil 5 of the solenoid valve 15c is connected in parallel to the coil 5 of the solenoid valve 15c.
VL8 and solenoid valve 21c coil 5VGc and relay contact 4
6c connected in series and the electromagnetic switch MRc are each connected in parallel to the power source 45 via the operation switch 40c of the indoor unit 30c.

In addition, the motor MC of compressor 2 is an electromagnetic switch MRa 1MR.
b Direct-acting solenoid valves 25a and 25b for bypass, which are connected in series to the circuit in which the normally open contacts MRa8° and MRc8 of 5MRc are connected in parallel, and connected to the power supply 45, and further connected in parallel.
, 25c, and relay contacts 43a, 43b, 43c connected in series with the coils Va, Vb, VC, respectively, and the four-way valve 4.
The circuit consisting of the coil 41 is connected in parallel to the power supply 45 through the heating side contact 48 of the cooling/heating changeover switch 42, and is further comprised of a microcomputer or the like and detects ON/OFF, etc. of the operation switches 40a, 40b, 40c. Possibly relay contact 43as43bs43c, 4
A control device 44 for controlling 6a, 46b, and 46c is connected to a power source 45.

Here, the operation of the multi-room air conditioner according to the present invention in the heating operation will be explained based on the above configuration.

Now, with the cooling/heating selector switch 42 set to the heating side contact 48 side, the operation switch 40 of the indoor unit 30a
If the compressor 2 is turned on, the control device 44 consisting of a microcomputer etc. detects that the indoor unit 30a has issued the first signal to rotate the motor MC of the compressor 2 which had been stopped. electric fm valve 21
Coil 5vLa of a, electromagnetic switch MRa and control device 4
A voltage is applied to the coil 5vGa of the solenoid valve 15a through the relay contact 46a, which is closed by the action of the solenoid valve 1.
5a and 21a at the same time, the normally open contact MRa8 of the electromagnetic switch MRa is closed, and the motor MC of the compressor 2 is rotated.

At this time, as mentioned earlier, the control device 44 is an indoor unit)
30a is stopped and the first control signal to rotate the motor MC of the RS compressor 2 is detected, so the normally open contacts of the relay contacts 43a, 43b, and 43c are kept open. (In this case, the coils Va and Vb of the direct-acting solenoid valves 25a, 25b, and 25c for bypass
, Vc are not energized.

Since the coil 41 of the four-way valve 4 is energized in this way, the refrigerant gas discharged from the compressor 2 passes through the four-way valve 4, the gas side main pipe 9, the gas side branch pipe 8a, and the solenoid valve 21a to the indoor unit 30a. The heat is radiated and liquefied to the inner heat exchanger 31a, and the connection port 16a, solenoid valve 15a, and several branch pipes 7
a, through the throttle device 22a, the branch point 13, and the liquid receiver 14, the pressure is reduced by the heating throttle mechanism 11, the water passes through the low-pressure circuit 20 during heating operation, is evaporated in the heat source side heat exchanger 5, and is then returned to the four-way valve 4. A refrigeration cycle is formed in which the air passes through the accumulator 10 and returns to the compressor 2, and the indoor unit 30a performs heating operation.

Incidentally, in this case, it goes without saying that the outdoor blower and the indoor blower in the indoor unit 30a are operating.

Also, when this indoor unit) 30a is in heating mode, the other indoor units 30b and 30c are switched to operation switches 40b and 40c.
Since the contacts of the solenoid valves 15b, 21b, 15c, and 21c are open, heating operation is not performed, and the coils 5VLb of the solenoid valves 15b, 21b, 15c, and 21c are open.
s 5VGb -5VLc -5VGc is not energized, so the solenoid valves 15a, 21b, 15e.

21c closes the passage.

Therefore, the refrigerating circuit 32b, which is closed by the solenoid valves 21b and 15b and includes the indoor heat exchanger 31b, and the refrigeration circuit 32c, which is closed by the solenoid valves 21c and 15c and includes the indoor heat exchanger 31c, are in a state in which no refrigerant flows. It is in.

However, it is actually the solenoid valve 21a. 21b, 21c, 15a
, 15b, 15c, etc. have a slight leakage that can completely stop the flow of refrigerant, so if the indoor units (30b, 3) are stopped,
The refrigerant gradually accumulates in the indoor heat exchanger 31 b s 31 c (this happens).

However, if the refrigerant accumulates in the indoor heat exchangers 31b and 31c (and the indoor unit in operation), the amount of refrigerant flowing through the indoor heat exchanger 31affi of the indoor unit 30a decreases, resulting in a decrease in heating capacity. A problem arises in that the compressor 2 is distorted.

Therefore, the indoor heat exchanger 3 is connected to the indoor heat exchanger 3 by bypasses W 19 b and 19 c, one end of which is connected to the low pressure circuit 20 during heating operation.
The refrigerant that has accumulated inside the 1cs31b is extracted.

Therefore, the refrigerant pressure in the indoor heat exchangers 31b, 31c of the indoor units 30b, 30c that are stopped is in the same low pressure state as the low pressure circuit 20 during heating operation.

Under these circumstances, when additionally operating another indoor unit 30b, the conventional control method
5b was open at the same time, so the indoor heat exchanger 3 was at low pressure.
Because high-pressure refrigerant gas flows into Ib at high speed due to the pressure difference, large refrigerant impact noises, vibrations, and intense valve punching noises of the solenoid valve 21b were generated.

Therefore, in the case of the present invention, as shown in the valve operation timing chart in FIG.
When turning on the motor M of the compressor 2, the control device 44 consisting of a microcomputer etc. switches the operation switch 40b to the motor M of the compressor 2 since the operation switch 40a has already been turned on.
It is detected that C is turned on during operation, and relay contact 46
When contact b is kept open and the normally open contact of relay contact 43b is closed to apply voltage to bypass direct-acting solenoid valve 25b coil vb, several branch pipes 22a and several pipes in which high-pressure liquid is flowing. The main pipe 6 and the refrigeration circuit 32b, which had been stopped and at a low pressure until now, are communicated through the bypass pipe 23b, and the liquid refrigerant enters the refrigeration circuit 32b.
The pressure at b is gradually increasing (.

Here, since the refrigerant flowing into the refrigeration circuit 32b through the bypass pipe 23b is in liquid form, the inflow speed is slow and no impact noise or the like is generated.

Also, at the same time as the coil vb of the solenoid valve 25b is energized, the liquid solenoid valve 15b for the indoor unit 30b which is additionally operated.
Since the coil 5vLb is also energized, the high-pressure liquid refrigerant in several main pipes 6 also passes through the refrigeration circuit 32b to the indoor heat exchanger 3.
1b, so the indoor heat exchanger 3Ib
It is possible to quickly (increase) the internal pressure.

Therefore, the indoor heat exchanger 3 can be quickly
The pressure within 1b can be increased.

In this way, the pressure inside the refrigeration circuits 32 b s 32 c increases to a certain extent, and when the solenoid valve 21 b is opened, the pressure difference between the pressure of the refrigerant flowing into the indoor heat exchanger 31 b and the pressure inside the gas side branch pipe 8 b becomes small. Control device 4 at the expected time
4 opens the contact of relay contact 43b, and relay 46b
Coil 5VGb of solenoid valve 21b in refrigeration circuit 32b that supplies refrigerant to indoor unit 30b when the normally closed contact of
Since the passage of the electromagnetic valve 21b is opened, the refrigerant flowing through the electromagnetic valve 21b enters the refrigeration circuit 32b with a small pressure difference, so that no impact noise or vibration is generated.

Also, the solenoid valve 21b does not suddenly hit the valve, so there is no need to disturb the valve.

Also, as in this embodiment, a direct acting solenoid valve 25a is used.

25 b s 25 c and check valves 26 a, 26 b
The combination of t 26 c can prevent refrigerant backflow at low cost.

Therefore, even if the pressure on the gas side branch pipes 8a, 8b, and 8c is higher than the pressure on the main pipe 6 side, it is possible to prevent the flow of refrigerant.

Therefore, the direct acting solenoid valve 25a. The refrigerant does not flow through 25b and 25c and the performance of the indoor unit during operation does not deteriorate.

Here, a bypass W23a is connected to the gas side branch pipes of the indoor unit 30a that has been operated from the beginning and the indoor unit 30c that has not been operated.

As explained above with reference to FIG. 2, the bypass solenoid valves 25a and 25c in 23c change the back pressure from the outlet pipe side in the case of the solenoid valve 25a, but the bypass pipe 2
There is no possibility that several refrigerants will bypass the gas side branch pipe 8a to the main pipe 6 through the gas side branch pipe 3a.

In the case of the solenoid valve 25c, since the pressure on the inlet pipe a side is higher than that on the outlet pipe side, refrigerant does not flow due to the original performance of the solenoid valve 25c.

In this way, the combination of a direct acting solenoid valve and a check valve eliminates the need to use expensive solenoid valves.

Further, in this embodiment, direct acting solenoid valves 25 a z 25 b for bypass in the bypass pipes 23 a, 23 b, and 23 c are used.
.

Although three solenoid valves 25c are provided, in order to reduce costs, only one solenoid valve 25 is provided, and the bypass pipe 23a is used.

23b and 23c may be attached to a common part where they are combined into one.

Further, in the electric circuit shown in Fig. 3, the operation switch 40a is
, 40bt40c is installed in series with a temperature controller, and when the operation switch is turned on and the temperature controller is restarted while other indoor units are operating and compression operation is in progress, if similar control is performed, the same effect can be achieved. It goes without saying that this can be obtained.

Furthermore, a direct-acting solenoid valve 25 a s 25 for bypass
b.

The opening time of 25c may be calculated and determined each time by a microcomputer, taking various conditions into consideration.

That is, the direct-acting solenoid valve for bypass may be controlled by various conditions such as the number of units in the operating room, thermostat temperature, thermostat switch, etc.

As mentioned above, in the multi-room air conditioner according to the present invention, when the compressor is running and there are few
When performing additional heating operation or restart operation of other indoor units using a thermostat, etc., the pipe line between the heating throttle mechanism and the source side solenoid valve, and the line between the gas side solenoid valve and the indoor heat exchanger In the bypass pipe connecting the refrigerant, the refrigerant is sent to the indoor heat exchanger via a direct-acting solenoid valve and then a check valve, and the source-side solenoid valve of the additional heating operation room is opened to release the refrigerant to the indoor unit, which had been inactive. Since the gas side solenoid valve is opened after the pressure inside the heat exchanger has increased, it is possible to perform quiet heating operation that produces no refrigerant noise or vibrations from the indoor unit, and it also eliminates the harsh effects of the gas side solenoid valve. The combination of a direct-acting solenoid valve and a check valve, which are both inexpensive and do not generate any gas-side solenoid valves, has the great effect of prolonging the life of the gas-side solenoid valve.

[Brief explanation of drawings]

Fig. 1 is a refrigeration cycle diagram of an embodiment of a multi-chamber air conditioner according to the present invention, Fig. 2 is a sectional view of a direct acting solenoid valve that constitutes a part of the circuit, and Fig. 3 is a refrigeration cycle diagram of an embodiment of the multi-chamber air conditioner according to the present invention. FIG. 4 is an electrical circuit diagram of an embodiment of the air conditioner, and FIG. 4 is an operation timing chart of a solenoid valve. 1...Outdoor unit, 7a, 7b, 7c...
...Several branch pipes, 15a, 15b, 15c" = solenoid valve,
19a, 19b, 19c... Bypass pipe (liquid drain pipe), 21 a, 21 b, 21 c = solenoid valve, 22
a. 22 b s 22 c...419 equipment, 23
a, 23b. 23 c ”” bypass pipe, 25 a s 25 b
, 25 c... Direct-acting solenoid valve for bypass,
30a, 30b. 30c...Indoor unit, 44...Control device, 4L 46at 46b-46c"--Relay contact, MC--Compressor motor, 5VLa, 5V
Lb. S V L c --- Solenoid valves 15a, 15b, 15c
coil, 5VGa, 5VGb, SVG o...-
--- Coils of solenoid valves 21a, 21b, 21c, Va
, V b sVc... Solenoid valves 25a, 25b
, 25c coil.

Claims (1)

[Claims] In a multi-room air conditioner in which multiple indoor units are connected to 11 outdoor units by connection piping, each of the main pipes of the outdoor units is branched into the liquid cylinder branch pipes created by the number of indoor units. A source side solenoid valve is provided, and a gas side solenoid valve is provided in each of the gas side branch pipes that have branched the gas side main pipe to the number of the indoor units, and a gas side solenoid valve is provided in each of the gas side branch pipes, and the source side solenoid valve in the liquid cylinder branch pipe and the number of the outdoor units are connected to each other. A throttle device is provided between the heat exchanger on the heat source side, and each of the gas side solenoid valves is connected to the gas side solenoid valve in the liquid cylinder branch pipe and the throttle device in the source main pipe. Bypass pipes communicating with the respective gas side branch pipes are provided between the valves and the utilization side heat exchangers of the respective indoor units, and each of the bypass pipes is energized only for the flow from the source side branch pipes to the gas side branch pipes. Whenever a direct-acting solenoid valve is interposed so that it can be stopped when the power is not energized, the refrigerant flow toward the source-side branch pipe is provided between the direct-acting solenoid valve and the gas-side branch pipe in the bypass pipe. A refrigeration circuit for a multi-chamber air conditioner equipped with a check valve to prevent