JPS642865B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a multi-type air conditioner comprising an outdoor unit and a plurality of indoor units.

[Technical background of the invention]

Generally, this type of air conditioner includes one equipped with a heat pump type refrigeration cycle as shown in FIG. In Figure 1, the town is an outdoor unit, B,
C and D are indoor units. Therefore, a variable capacity compressor (variable rotation speed) 1, a four-way valve 2, an outdoor heat exchanger 3, capillary tubes 4, 5, a pressure reducing device such as an expansion valve 6, a capillary tube for branch flow control 11, 21, 31, Liquid line on/off valve 12, 22,
32, indoor heat exchangers 13, 23, 33, glass-in on-off valves 14, 24, 34, etc. are connected in sequence,
A heat pump type refrigeration cycle is constructed. That is, the indoor heat exchangers 13, 23, and 33 are arranged in parallel. During cooling operation, the refrigerant flows in the direction of the solid arrow shown in the figure, and during heating operation, the four-way valve 2 is switched, so that the refrigerant flows in the direction of the broken line arrow.

A capillary tube 41 is provided between the refrigerant outlet pipe of the expansion valve 6 and the compression chamber of the compressor 1.
A liquid injection cycle 40 is provided via. This liquid injection cycle 40
is for injecting liquid refrigerant into the compression chamber of the compressor 1.

In addition, the liquid line on-off valve 12 and the indoor heat exchanger 13
One end of a liquid return cycle 50 is connected to the refrigerant pipe between the capillary tubes 4 and 5 and the expansion valve 6 via a capillary tube 51. will be communicated to. One end of a liquid return cycle 60 is connected to the refrigerant pipe between the liquid line on-off valve 22 and the indoor heat exchanger 23, and the other end of this liquid return cycle 60 is connected to the capillary tube 4, via a capillary tube 61. The refrigerant pipe between the expansion valve 5 and the expansion valve 6 is connected to the refrigerant pipe. One end of a liquid return cycle 70 is connected to the refrigerant pipe between the liquid line on-off valve 32 and the indoor heat exchanger 33, and the other end of the liquid return cycle 70 is connected to the capillary tube 4, via a capillary tube 71. The refrigerant pipe between the expansion valve 5 and the expansion valve 6 is connected to the refrigerant pipe. These liquid return cycles 50, 60, 70 are
It has the following functions. That is, when heating operation is performed in indoor units B, C, and D, for example, when the operation of indoor unit C is stopped, the gas line on-off valve 24 and the liquid line on-off valve 22 are closed, and the indoor heat is released. The discharge gas refrigerant is prohibited from flowing into the exchanger 23.
At this time, the discharge gas refrigerant that has already flowed into the indoor heat exchanger 23 accumulates there, and since the accumulated discharge gas refrigerant has a high temperature, it exchanges heat with the outside and is gradually cooled and becomes liquid. If the liquid refrigerant accumulates in the indoor heat exchanger 23, the gas balance of the refrigeration cycle will be disrupted when the operation of the indoor unit C is restarted, and further, the compressor 1
There is a risk that the liquid refrigerant returns to the compressor 1 and causes liquid compression, causing damage to the compressor 1. Therefore, the liquid refrigerant generated in the indoor heat exchanger 23 is returned to the liquid line side by the liquid return cycle 60 to prevent the above-mentioned problems from occurring.

[Problems with background technology]

By the way, in such an air conditioner, when the indoor unit C is out of operation, the gas line on-off valve 24
Since the refrigerant pressure on the side is higher than the refrigerant pressure on the liquid line opening/closing valve 22 side, when the operation of the indoor unit C is restarted in this state, the discharged gas refrigerant suddenly flows into the indoor heat exchanger 23, and a large refrigerant There was a problem in that the noise generated caused discomfort and a sense of distrust for the people in the room.

[Purpose of the invention]

This invention was made in view of the above circumstances, and its purpose is to suppress the refrigerant noise when the idle unit starts operating, thereby improving reliability. Our goal is to provide air conditioners.

[Summary of the invention]

The present invention provides a high-pressure release cycle and a refrigerant injection cycle from the high-pressure release cycle to each indoor heat exchanger via a pressure reducing device, thereby controlling the operation of at least one of the indoor heat exchangers. When starting the indoor heat exchanger, the high-pressure release cycle is first turned on and refrigerant is gradually injected into the indoor heat exchanger before opening the on-off valve corresponding to the indoor heat exchanger.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. However, in the drawings, the same components as in FIG. 1 are denoted by the same reference numerals, and detailed explanation thereof will be omitted.

As shown in FIG. 2, a high-pressure release on-off valve 81 and a capillary tube 8 are provided between the refrigerant inlet pipe of the expansion valve 6 and the refrigerant suction pipe of the compressor 1.
A high pressure release cycle 80 is provided via 2. In this high pressure release cycle 80, each indoor heat exchanger 13, 23, 3 is
3, a pressure reducing device such as a capillary tube 91,
Refrigerant injection cycle 9 via 92 and 93, respectively.
4, 95, and 96 are arranged.

FIG. 3 is a diagram showing the main parts of the control circuit. Unit B operation signal (AC power supply voltage) V ₁ is connected between terminals 101 and 102, unit C operation signal (AC power supply voltage) V ₂ is connected between terminals 101 and 103, and terminal 10
A unit D operation signal (AC power supply voltage) V ₃ is applied between terminals 1 and 104, and a high voltage release signal (AC power supply voltage) V ₄ is applied between terminals 101 and 105. Thus, the on-off valve drive relay 111 for unit B is connected between terminals 101 and 102, the on-off valve drive relay 112 for unit C is connected between terminals 101 and 103, and the on-off valve drive relay 113 for unit D is connected between terminals 101 and 104. , an excitation coil 81C of the high-pressure release on-off valve 81 is connected between the terminals 101 and 105.

Further, a heater 121h of a thermal timer 121 is connected between the terminals 101 and 102 via a relay contact 111a, and a relay contact 11
Excitation coils 14c and 12c of the on-off valves 14 and 12 are connected through the normally open side of the timer contact 1a and the timer contact 121a. A heater 122h of a thermal timer 122 is connected between terminals 101 and 103 via a relay contact 112a, and a relay contact 1
12a and the excitation coils 24c, 22c of the on-off valves 24, 22 via the normally open side of the timer contact 122a.
is connected. A heater 123h of a thermal timer 123 is connected between the terminals 101 and 104 via a relay contact 113a, and excitation coils 34c and 32 of the on-off valves 34 and 32 are connected via the normally open sides of the relay contact 113a and the timer contact 123a.
c is connected.

One end of the excitation coil 81c is connected to a series circuit between the relay contact 111a and the normally closed side of the timer contact 121, a series circuit between the relay contact 112a and the normally closed side of the timer contact 122, and a series circuit between the relay contact 113a and the normally closed side of the timer contact 123. They are connected to terminals 102, 103, and 104 via series circuits with the closed side, respectively.

By the way, the thermal timers 121, 122, 1
23, a timer contact is activated after a certain period of time due to the heat generated by the heater, and the certain period of time is 5 seconds or more.

Next, the operation in the above configuration will be explained.

Now, when heating operation is set in indoor unit B, the four-way valve 2 is switched, the compressor 1 starts operating, and the unit B operation signal _V1 is generated. Then, the relay 111 is activated, and the relay contact 111a is turned on, thereby energizing the heater 121h of the thermal timer 121. At the same time, the on-off valve 81 is opened. When the on-off valve 81 opens, the refrigerant accumulated in the refrigeration cycle flows from the high-pressure release cycle 80 through the refrigerant injection cycles 94, 95, and 96 to the indoor heat exchangers 13, 23, and 33. The internal pressure of increases. In this way, when the internal pressure has risen sufficiently, the timer contact 121h is activated, the on-off valve 81 is closed, and the on-off valves 14, 12 are closed.
is opened, a heating cycle is formed through the indoor heat exchanger 13, and heating operation is started in the indoor unit B. At this time, the on-off valves 14, 12
When the indoor heat exchanger 13 is opened, the internal pressure of the indoor heat exchanger 13 increases, so the pressure fluctuation in the indoor heat exchanger 13 is very small, and no refrigerant noise is generated.

When indoor unit B is operating, if indoor unit C is set to heating operation, unit C operation signal is
V ₂ occurs. Then, relay 112 is activated,
By turning on the relay contact 112a, the heater 122h of the thermal timer 122 is energized. At the same time, the on-off valve 81 is opened. When the on-off valve 81 operates to open, high pressure is released, and from the high pressure release cycle, the indoor heat exchangers 23, 33 pass through the refrigerant injection cycles 95, 96.
Refrigerant (gas) flows into the indoor heat exchangers 23 and 33, and the internal pressure of each of the indoor heat exchangers 23 and 33 increases. In this case, no refrigerant flows into the indoor heat exchanger 13 due to pressure balance. Moreover, the refrigerant flowing into the indoor heat exchangers 23, 33 gradually flows in due to the presence of the capillary tubes 92, 93, and no refrigerant noise is generated. In this way, when the internal pressure has risen sufficiently, the timer contact 122h is activated, the on-off valve 81 is closed, the on-off valves 24 and 22 are opened, and a heating cycle is also formed through the indoor heat exchanger 23, and the indoor heat exchanger 23 is heated. Heating operation is started in unit C. At this time, since the internal pressure of the indoor heat exchanger 23 is rising when the on-off valves 24 and 22 are opened, the pressure fluctuation in the indoor heat exchanger 23 is very small, and no refrigerant noise is generated.

By the way, since the high-pressure release on-off valve 81 is used for both high-pressure release and refrigerant injection, there is a concern that the internal pressure of the idle heat exchanger will not rise sufficiently, but refrigerant injection is performed even during high-pressure release. Therefore, the capillary tube 8
There is no problem even if the orifice No. 2 is made a little larger, and the pressure increase in the downstream stage of the on-off valve 81 can be measured accordingly, and the capillary tubes 91, 92, 93
By loosening the restriction, the internal pressure can be sufficiently increased. In addition, refrigerant is injected not only into the operating indoor heat exchanger but also into other idle heat exchangers, but the extra injected refrigerant is recovered in the liquid return cycle, so there is no sacrifice in performance.

Although a thermal timer is used as the timer in the above embodiment, the timer is not limited to this, and a motor type or electronic type timer may be used.Furthermore, the timer function may be dependent on software control by a microcomputer. This would be advantageous in terms of cost. Further, although the case where there are three indoor units has been described, the same method can be applied to a case where there are more indoor units.

In addition, in the above embodiment, refrigerant is injected from the high pressure release cycle, but as shown in FIGS. A refrigerant injection cycle 144, 145, 146 is arranged through the capillary tube 141, 142, 143, and the excitation coil 131c of the on-off valve 131 is connected with relay contacts 111, 112, 113 and timer contacts 121, 122, 123. A similar effect can be obtained by applying the heating operation signal (AC power supply voltage) _V5 through each of them.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide an excellent air conditioner that can suppress refrigerant noise when the idle unit starts operating, thereby improving reliability.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an example of a conventional heat pump type refrigeration cycle, FIG. 2 is a configuration diagram of a heat pump type refrigeration cycle in an embodiment of the present invention, and FIG. 3 is a configuration diagram of a control circuit in the same embodiment. FIG. 4 is a block diagram of a heat pump type refrigeration cycle showing another embodiment of the present invention, and FIG. 5 is a block diagram of a control circuit in the same other embodiment. 1... variable capacity compressor, 3... outdoor heat exchanger,
13,23,33...Indoor heat exchanger, 12,1
4, 22, 24, 32, 34...on/off valve, 80...
...High pressure release cycle, 81...High pressure release on/off valve, 91,92,93...Capillary tube (pressure reducing device), 94,95,96...Refrigerant injection cycle.

Claims (1)

[Claims] 1 Compressor, four-way valve, outdoor heat exchanger, pressure reducing device,
A heat pump refrigeration cycle consisting of a plurality of parallel indoor heat exchangers connected in sequence, and a refrigerant pipe connected to each of the indoor heat exchangers, respectively, to control refrigerant inflow to each indoor heat exchanger. An on-off valve, a high-pressure release cycle arranged from the refrigerant piping between each of the indoor heat exchangers and the pressure reducing device to the refrigerant suction side piping of the compressor, and a high-pressure release opening/closing valve provided in this high-pressure release cycle. a refrigerant injection cycle arranged from the high-pressure release cycle downstream of the high-pressure release on-off valve to each of the indoor heat exchangers via a pressure reducing device, and the operation of at least one of the indoor heat exchangers. An air conditioner comprising: a control circuit that temporarily opens the high-pressure release on-off valve before opening the on-off valve corresponding to the indoor heat exchanger when starting the air conditioner.