JPS5914702B2 - 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, so that quiet heating operation can be performed.

One of its purposes is to

In a conventional multi-room air conditioner, when the indoor unit is in warm 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, the indoor heat exchanger of the indoor unit that was subjected to this additional heating operation had the gas side solenoid valve and the source side solenoid valve closed before the heating operation was started, and the flow of refrigerant had been stopped. Since it was connected to a low-pressure circuit, the pressure was almost the same as the suction pressure of the compressor.

For this reason, if the gas side solenoid valve and the source side solenoid valve are opened simultaneously, high pressure gas will flow into the low pressure indoor heat exchanger at high speed, and this flowing refrigerant will generate a loud impact sound on the gas side. By violently moving the pilot valve part of the solenoid valve, a clicking sound can be generated.

These impact noises and lunch box 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 one embodiment thereof will be described below with reference to the drawings.

FIG. 1 is a refrigeration cycle diagram of an embodiment of a multi-room air conditioner according to the present invention, in which an outdoor unit 1 includes a compressor 2, a discharge muffler 3, a four-way valve 4, a heat source side heat exchanger 5, and a source side main pipe. 6,
Source-side branch pipe 7a formed by branching source-side main pipe 6 at branch point 13
, 7b, 7c, and the same number of gas side branch pipes 8a*8by8cs as these source side branch pipes 7a, 7b, and 7c.

Gas side main pipe 9 made by collecting sb, 8c, accumulator 10, heating coarse throttle 9 installed in liquid main pipe 6
and a check valve 12 provided in parallel with the heating throttle mechanism 11 to block the flow of refrigerant during heating operation, a rough heating throttle 9 of the source side main pipe 6, an isometric structure 11, and a source side branch pipe 7a; 7b, 7
A liquid receiver 14 provided between the branch part 13 of c and each source side branch pipe 7a, 7b.

Bidirectional squeezing mechanism 22 a e 22 b in 1c
.

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

15b, 15c, each solenoid valve 15 a s 15 b, 1
5c and each source side branch pipe 7a between the heating throttle mechanism 11
e7 b s 7 c or the source side main pipe 6 and the utilization side heat exchanger 31a of each indoor unit 30a, 30b, 30c.

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

Gas side branch pipe 8 a e 8 b * 8 between 21c
Bypass pipes 23a, 23b, 23c connecting between c.
.

This bypass pipe 23 a t 23 b * 23 c
The refrigerant is provided inside the refrigerant and has a structure that allows only the flow of refrigerant toward the gas side branch pipes 8a, 8b, and 8C when energized, and can block the flow from each gas side branch pipe 8a, 8b, and 8c regardless of whether the current is energized or not. One-way flow pilot type bypass solenoid valves 25a, 25b.

25c1 Check valves 17a, 17b, 17c and throttle 1 provided in a direction that allows refrigerant to flow toward the low pressure circuit 20 side during heating operation
8 a p 18 b , 18 c are connected in series, respectively. source side branch pipe 7a.

Bypass pipe 19 a p connecting 7 b * 7 c and the low pressure circuit 20 during heating operation 19 a p 19 b * 19 c-
Bidirectional flow solenoid valves 21a, 21b, 21c provided in the gas side branch pipes 8a, 8b, and 8c, respectively.
It becomes more.

Note that the outdoor unit 1 has a heat source side heat exchanger 5/? :Equipped with a blower (not shown) that blows air.

Further, the indoor units 30a, 30b, and 30c each include user-side heat exchangers 31a, 31b, and 31c, and an indoor blower that blows into the room the air that has been heat-exchanged in each of the user-side heat exchangers 31a, 31b, and 31c.

Further, the one-way flow pilot type bypass solenoid valves 25a, 25b, and 25c used here are constructed as shown in FIG.

In FIG. 2, the solenoid valve 25 includes an inlet pipe a1, an outlet pipe, a valve body 50 whose position is fixed, and a solenoid coil 5.
It is composed of a spring 53 that pushes down the plunger 52 that is pulled up by the valve body 50, and a cylindrical body 54 that houses the pilot valve 57 and the like located between the valve body 50 and the plunger 52, and performs the following operations.

Assuming that the electromagnetic coil 51 is now in a non-energized state, the cylindrical body 5
4 and the pilot valve 57 and the plunger 52, a space is created by the pressure Pa inside the inlet pipe a and the positional relationship between the cylinder 54, the pilot valve 57, and the plunger 52. The pressures Pc of are equal.

The area of the surface where the plunger 52 contacts the spring 53 is Ap, the area of the valve seat 56 with the diameter d of the valve body 50 is Av, and the force of the spring 53 to push down the plunger 52 is FS%. If Fp1 is the automatic pilot valve, Fpi is the plunger 52.
The pushing down force F1 is F1 = Fs+Fp+Fpi +Ap-P
It becomes a.

On the other hand, a force F trying to push the plunger 52 upward
2 is F2=AV-Pb if the pressure inside the outlet pipe is Pb
becomes.

Therefore, at least the relationship between pressure Pa and Pb is P a >
In the case of Pb, the relationship between F1 and F2 is Fl>F2, so the plunger 52 is being pushed down with a strong force, and as a result, the pilot valve 57 is also being pushed down with a strong force. The valve seat portion 56 is the pilot valve 5
7 and the hole 55 of the valve body 50 is closed by the tip 58 of the pilot valve 57.

Therefore, the inlet pipe a and the outlet pipe A do not communicate with each other.

From this state, the electromagnetic coil 51 is energized.
The shield plunger 52 is pulled up by Fc by the magnetic force of 1.

Here, the pressure Pb in the outlet pipe is the pressure P in the space created by the plunger 52, the pilot valve 51, and the cylinder body 54 through the hole 55 of the valve body 50 and the hole 59 of the pilot valve 57.
Let c be the same as Pb.

That is, the pressure Pc in this space changes from the state of Pc=Pa to Pc=
The Pb pilot valve 57 is pushed upward from below by the pressure Pa in the inlet pipe a, and eventually a gap is created between the valve seat 56 of the valve body 50 and the tip 58 of the pilot valve 57 through which the refrigerant flows. The inlet pipe A and the outlet pipe A are now in communication.

On the other hand, when the electromagnetic coil 51 is de-energized, the pressure inside the outlet pipe P
Even if b is larger than the pressure Pa in the inlet pipe a to some extent, the plunger 52 and the pilot valve 57 are not pushed upward.

This is because in order to overcome the plunger 52, pilot valve 57, and spring Pc and push up the plunger valve 57, a considerably larger force is required compared to a direct acting solenoid valve that only has a plunger.

Under this condition, when the electromagnetic coil 51 is further energized, the plunger 52 rises because <Pc=Pa as described above.

Then, the hole 55 of the valve body 50 and the hole 59 of the pilot valve 57
High-pressure refrigerant is injected into the space between the cylinder 54, the pilot valve 57, and the plunger 52, and the refrigerant force Pc (=pt)) in this area is greater than the pressure Pa, and the area above the pilot valve 57 is Area below Apid
Since is small, Apiu + P b + F pi =
As ApiuPc+Fpi>ApidPa, the tip 58 of the pilot valve 57 is pressed strongly against the valve seat 56 of the valve body 50, and as a result, the inlet pipe a is not communicated with the outlet pipe.

As mentioned above, the pilot type solenoid valve 25 is connected to the solenoid coil 5.
When the electromagnetic coil 51 is energized, the refrigerant is allowed to flow from the inlet pipe a to the outlet pipe A, and when the electromagnetic coil 51 is de-energized, the flow of refrigerant from the inlet pipe a to the outlet pipe A is blocked. Therefore, the structure is such that the refrigerant flow to the inlet pipe a is not allowed whether or not the electromagnetic coil 51 is energized.

FIG. 3 shows an embodiment of the electric circuit of the multi-room air conditioner according to the present invention, in which the coil 5Vja of the solenoid valve 15a and the solenoid valve 21
The circuit in which the coil 5Voa of a and the relay contact 46a are connected in series and the electromagnetic switch MRa are both indoor units)
The electromagnetic switch MRb is connected in parallel to the power supply 45 via the operation switch 40a of 30a, and similarly connects the coil 5VLb of the electromagnetic valve 15b and the coil SV of the electromagnetic valve 21b in series with the relay contact 46b and the electromagnetic switch MRb. Indoor unit) 30b is connected in parallel to the power supply 45 via the operation switch 40b, and similarly the coil 5VL of the solenoid valve 15c is
C, coil 5VGC of solenoid valve 21c and relay contact 46c
The circuit in which these are 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.

Furthermore, the motor MC of the compressor 2 is an electromagnetic switch MRa. MRb
, MRc are connected in series with a circuit in which the normally open contacts MRas, MRbs, and MRcs are connected in parallel, and connected to the power supply 45.
Furthermore, the coils V of the unidirectional via-type bypass solenoid valves 25a, 25b, and 25c are connected in parallel.
The circuit consisting of the relays 43 a * 43 b - 43 c and the coil 41 of the four-way valve 4 connected in series with a y V b = V c is the cooling/heating changeover switch 42
The relay contacts 43a, 43b, 43c are connected in parallel to the power supply 45 through the heating side contacts 48 of the controllers, and are connected in parallel to the power supply 45 through the heating side contacts 48, and are further comprised of a microcomputer, etc., and detect ON, OFF, etc. of the operation switches 40a, 40b, 40c.
, 46a, 46b, and t46c.
4 are each connected to a power source 45.

Here, the operation of the multi-room air conditioner according to the present invention during heating operation will be explained.

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 or the like detects that the indoor unit 30a has issued the first signal to rotate the motor MC of the compressor 2, which had been stopped. The solenoid valve 1 is connected to the solenoid valve 1 through the coil 5VLa of the solenoid valve 21a, the solenoid switch MRa, and the relay contact 46a that is closed by the action of the control device 44.
A voltage is applied to the coil 5vGa of the solenoid valve 15a,
21a at the same time to open the normally open contact MR of the electromagnetic switch MRa.
as is closed and the motor MC of the compressor 2 is rotated.

At this time, as mentioned earlier, the control device 44 has detected that the indoor unit 30a has issued the first control signal to rotate the motor MC of the compressor 2, which has been stopped, so the relay contact The normally open contacts of 43a, 43b, and 43c are kept open, and the coils Va, vb, and Vc of the one-way pilot type bypass solenoid valves 25a, 25b, and 25c 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 further the connection port 16a1 solenoid valve 15a liquid side branch pipe 7a
, the throttle device 22a1 branch point 13, the liquid receiver 14, the pressure is reduced by the heating throttle mechanism 11, and the low pressure circuit 2 during heating operation
0, evaporates in the heat source side heat exchanger 5, passes through the four-way valve 4 again, returns to the compressor 2 via the accumulator 10, forming a refrigeration cycle, and the indoor unit 30a performs heating operation.

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

Also, during heating operation of this indoor unit 30a, other indoor units) 30b.

30c opens the contacts of the operation switches 40b and 40c, so heating operation is not performed, and the solenoid valve 15 b s
2 l b -15c s 21 c coil 5VLb
.

Since 5VGb*5VLc and 5VGc are not energized, the solenoid valves 15a, 21b, 15c, and 71c close their passages.

Therefore, refrigerant does not flow in the refrigeration circuit 32b that is blocked by the solenoid valves 21b and 15b and includes the indoor heat exchanger 31b, and in the refrigeration circuit 32c that is blocked by the solenoid valves 21c and 15c and includes the indoor heat exchanger 31c. in a state.

However, in reality, the solenoid valve 21 a = 21 by 21
ct15a, 15b, 15c, etc. cannot completely stop the flow of refrigerant and there is some leakage, so please use indoor units that are stopped)
30 b s 30 c indoor heat exchanger 31b.

The refrigerant gradually accumulates in 31c.

However, when a large amount of refrigerant accumulates in the indoor heat exchangers 31b and 31c, the amount of refrigerant flowing through the indoor heat exchanger 31a of the indoor unit 30a during operation decreases, resulting in a decrease in heating capacity and The problem arises that it may mimic the horizontal rule of 2.

Therefore, the indoor heat exchangers 31b, 3 are connected to the bypass pipes 19b, 19c, which have one end connected to the low pressure circuit 20 during heating operation.
The refrigerant accumulated in 1c 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.
Due to the pressure difference, high-pressure refrigerant gas flows into the valve 1b at high speed, causing large refrigerant impact noises, vibrations, and intense lunchbox noises from the solenoid valve 21b.

Therefore, in the case of the present invention, the operation switch 40 of the indoor unit 30b is turned on as shown in the valve operation timing chart in FIG.
When the power switch 40b is turned on, the control device 44, which is a microcomputer or the like, 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 the contact b is left open and the normally open contact of the relay contact 43b is closed to apply voltage to the coil vb of the one-way pilot type bypass solenoid valve 25b, the liquid side branch pipe 22a in which high-pressure liquid is flowing is applied. The refrigeration circuit 32b, which had been at low pressure because it had been stopped until now, is communicated with the main pipe 6 on the source side through the bypass pipe 23b, and as the liquid refrigerant enters, the pressure in the refrigeration circuit 32b gradually increases. go.

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.

In addition, a one-way flow pilot type bypass solenoid valve 25
Coil 5VL of liquid electromagnetic valve 15b for indoor unit 30b which was additionally operated at the same time as energization to coil vb of
Since current is also applied to the liquid refrigerant in the liquid side main pipe 6, the high pressure liquid refrigerant in the liquid side main pipe 6 also flows into the indoor heat exchanger 31b through the refrigeration circuit 32b and sag, causing the pressure in the indoor heat exchanger 3Ib to increase quickly. I can do it.

Therefore, the indoor heat exchanger 3i can be quickly heated without generating impact noise.
The pressure within b can be increased.

In this way, the pressure inside the refrigeration circuits 32b and 32c increases to a certain extent, and when the solenoid valve 21b is opened, the indoor heat exchanger 31b
When the pressure difference between the refrigerant pressure flowing into the gas side branch pipe 8b and the pressure inside the gas side branch pipe 8b seems to have become small, the control device 44 opens the contact of the relay contact 43b and closes the normally closed contact of the relay 46b. Since the coil 5vGb of the solenoid valve 21b in the refrigeration circuit 32b that supplies refrigerant to the refrigeration circuit 30b is energized and the passage of the solenoid valve 21b is opened, the refrigerant flowing through the solenoid valve 21b flows into the refrigeration circuit 32b with a small pressure difference. Since it is inserted, there is no impact noise or vibration.

Also, the solenoid valve 21b does not cause any unnecessary valve changes, so the valve will not be damaged.

The indoor unit 30a that is being operated from the beginning and the indoor unit that is not being operated) are the one-way pilot type bypass solenoid valves 25a in the bypass pipes 23a and 23c that are connected to the gas side branch pipes 8a and 8c of the indoor unit 30c.
and 25c operate as follows.

First, in the case of the solenoid valve 25a, the pressure on the outlet pipe side is
The pressure on the side is high.

Therefore, regardless of whether the electromagnetic coil 51 is energized or not, the refrigerant will not flow through the bypass pipe 23a from the gas side branch pipe 8a to the source side main pipe 6 side due to the characteristics of its structure.

In the case of the bypass solenoid valve 25c, the pressure on the inlet pipe a side is higher than the pressure on the outlet pipe side, so if the electromagnetic coil 51 is de-energized, due to the original characteristics of the bypass solenoid valve 25c, the pressure in the bypass pipe 23c will be higher. Do not flow refrigerant into the

In this way, the one-way flow pilot type solenoid valve 25 a
By using only y 25 b y 25 c, it is possible to flow or stop the refrigerant in only one direction in the bypass pipes 23a, 23b, 23c, and to constantly stop the flow in the other direction. become.

In this way, the pilot-type bypass solenoid valves 25a, 25b, and 25c with one-way flow are configured to allow the refrigerant to flow only in the direction toward the gas side branch pipes sa, sb, and sc in the bypass pipe, thereby making it possible to When an indoor unit is already being supplied with refrigerant, when another indoor unit is additionally operated or restarted using a thermostat, etc., no loud refrigerant noise is generated from other rooms.
Moreover, the above features can be achieved with a simple refrigerant circuit at low cost.

Moreover, in this embodiment, the bypass pipes 23 a s 23 b
One-way flow pilot type bypass solenoid valve 25a for bypass during s23c.

There are three bypass solenoid valves 25b and 25c, but in order to reduce the cost, only one bypass solenoid valve 25 is provided, and the bypass pipe 23
The a s 23 b and 23 c may be attached to a common bypass pipe unit.

Furthermore, in the electric circuit of FIG. 2, the operation switch 40a
, 40b, 40c, and if the same control is performed 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, exactly the same effect can be obtained. It goes without saying that this can be obtained.

Furthermore, one-way flow pilot type bypass solenoid valve 2
The opening time of 5 a s 25 b -25c can be calculated and determined each time by a microcomputer, taking various conditions into consideration. There are various factors such as OFF time.

Alternatively, a one-way pilot type bypass solenoid valve may be controlled by a pressure switch or the like.

As described above, in the multi-room air conditioner according to the present invention, when the compressor is running and at least one indoor unit is in heating operation,
When performing additional heating operation or restarting other indoor units using a thermostat, etc., the pipe line between the coarse heating throttling mechanism and the source side solenoid valve, and the line between the gas side solenoid valve and the indoor heat exchanger. By installing a pilot type bypass solenoid valve with one-way flow so that the refrigerant flows only in the direction of the gas side branch pipe in the bypass pipe connecting the indoor units, the source side branch pipes on the indoor unit side can be bypassed and additional heating can be achieved. The source-side solenoid valve in the operator's cabin is opened to increase the pressure in the indoor heat exchanger of the indoor unit that has been inactive, and then the gas-side solenoid valve is opened. By installing one pilot-operated solenoid valve for each, quiet heating operation is possible without refrigerant impact noise and vibration from the indoor unit, and there is no strong gas-side solenoid valve sagging, and the gas-side solenoid valve It has great effects such as prolonging the lifespan.

[Brief explanation of the drawing]

Fig. 1 is a refrigeration cycle diagram of an embodiment of the multi-chamber air conditioner according to the present invention, Fig. 2 is a sectional view of a pilot type solenoid valve that constitutes the refrigeration cycle, 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 electric circuit diagram of an embodiment of the harmonizer, and FIG. 4 is an operation timing chart of the solenoid valve. 1...Outdoor unit? a, 7b, 7c...
・・Source side branch pipe, 15a, 1 sb, 15c・・
...Solenoid valve, 19a. 19b, 19c... Bypass pipe (liquid drain pipe),
21 a, 21 b, 21 c ''--Solenoid valve, 22 a. 22 b * 22 c '' Throttle device, 23 a-
23b s23 c = bypass pipe, 25a, 25b,
25c... Pilot type bypass solenoid valve, 3
0 ay 30b. 30c... Indoor unit, 44... Control device, 43° 46a, 46b, 46c = relay contact, MC... Compressor motor, SVL a,
SVL b, SVL c ””・Solenoid valve, 15a
, 15b, 15c coils, S V o a 5SVG
b, SVG c "" Solenoid valves 21a, 21b, 2
Coil 1c, Va, Vb, VC... Solenoid valve 2
5 ay 25b. 25c coil.

Claims (1)

[Scope of Claims] In a multi-room air conditioner in which a plurality of indoor units are connected to 11 outdoor units by connection piping, the source side main pipe of the outdoor unit is branched to the number of the indoor units. A source side electromagnetic valve is provided in each of the source side branch pipes created, and the gas side main pipe is branched into the gas side branch pipes created by branching the gas side main pipe to the number of indoor units. a gas-side solenoid valve in each of the source-side branch pipes, a throttling device is provided between the source-side solenoid valve in the source-side branch pipe and the heat source-side heat exchanger of the outdoor unit, and each source-side solenoid valve in each of the source-side branch pipes and a pipe line between the throttle device in the liquid side main pipe, and each of the gas side solenoid valves. A bypass pipe is provided that communicates with each gas side branch pipe between the user side heat exchangers of the indoor unit, and each of the bypass pipes allows only a flow from the source side branch pipe to the gas side branch pipe when energized. A unidirectional pilot type solenoid valve is installed. Refrigeration circuit of indoor air conditioner.