JP2009145026A - Multiple type air conditioner, and solenoid valve unit used for refrigerant leakage-prevention measure of indoor expansion valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a liquid refrigerant from leaking into a heat exchanger of an indoor unit in stopping even if a shutoff property of the indoor expansion valve is degraded while operating an air conditioner in a cooling mode. <P>SOLUTION: A solenoid valve 18 is arranged on an outdoor unit 1 side relative to an indoor expansion valve 13, the solenoid valve 18 is totally closed based on a stop instruction of each indoor unit 2 or a total closure control signal of the indoor expansion valve, and thereby the liquid refrigerant is prevented from leaking into the indoor heat exchanger 12 of the indoor unit 2 in stopping even if the shutoff property of the indoor expansion valve 13 is degraded. A check valve bypassing the solenoid valve is arranged to prevent the refrigerant and refrigerator oil from being accumulated in the indoor heat exchanger 12 even when the solenoid valve 18 is totally closed when a stop instruction of each indoor unit 2 is input in a heating mode, and a passage returning the refrigerant and the refrigerator oil to the outdoor unit is secured. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a multi-type air conditioner in which a plurality of indoor units are connected to a single outdoor unit, and more specifically, a multi-type air conditioner provided with countermeasures against refrigerant leakage of an indoor expansion valve provided in the indoor unit. The present invention also relates to a solenoid valve unit used for countermeasures against refrigerant leakage of an indoor expansion valve.

  As described in Patent Documents 1 and 2 and the like, the multi-type air conditioner connects a gas refrigerant pipe and a liquid refrigerant pipe of a plurality of indoor units in parallel to a gas refrigerant pipe and a liquid refrigerant pipe of one outdoor unit. Configured. In such a multi-type air conditioner, in order to allow the user to individually operate or stop each indoor unit, the indoor expansion valve provided in the liquid refrigerant pipe of each indoor unit is opened and closed to The refrigerant is circulated or shut off in the exchanger.

  On the other hand, foreign materials such as wear powder generated by compressor operation, dust mixed during pipe connection work, flux generated during pipe brazing, etc. are mixed in the circulating refrigerant and move in the refrigeration cycle together with the refrigerant. If foreign matter bites into the valve body of the expansion valve and the valve seat closed portion, the expansion valve is damaged and performance is impaired. Therefore, a strainer with fine eyes (for example, 100 mesh) is usually provided at the inlet and outlet of the expansion valve to prevent foreign matters in the circulating refrigerant from biting into the expansion valve.

Japanese Patent Laid-Open No. 9-310931 Japanese Patent Laid-Open No. 3-156264

  However, in Patent Documents 1 and 2, fine foreign matter that cannot be removed by the strainer bites into the valve portion of the indoor expansion valve, and the valve body does not come into close contact with the valve seat. There is a possibility that the contacting seat surface may be damaged, and the problem in the case where the indoor expansion valve does not completely close is not taken into consideration.

  That is, when the closing performance of the indoor expansion valve is reduced, for example, when the multi-type air conditioner is operating in the cooling mode, the indoor expansion of the indoor unit is stopped in order to individually stop the operation of any indoor unit. Even when the valve is closed, the high-pressure liquid refrigerant supplied from the outdoor unit side passes through the gap of the indoor expansion valve, expands under reduced pressure, and leaks into the heat exchanger of the indoor unit. As a result, the ambient air around the heat exchanger of the indoor unit is cooled, natural convection of the ambient air occurs, the parts placed around the heat exchanger are condensed, and the dew condensation water falls from the indoor unit and the room May be soiled.

  The problem to be solved by the present invention is that, in a multi-type air conditioner operating in the cooling mode, liquid refrigerant leaks into the heat exchanger of the stopped indoor unit even if the closing performance of the indoor expansion valve is reduced. There is to be no.

  A first aspect of the present invention that solves the above problem is configured by branching from a gas refrigerant pipe and a liquid refrigerant pipe of one outdoor unit and connecting a plurality of indoor units in parallel. In a multi-type air conditioner provided with an indoor expansion valve in a refrigerant pipe and having a control device for fully closing the corresponding indoor expansion valve based on a stop command for each indoor unit in a cooling mode, An electromagnetic valve is provided closer to the outdoor unit than the indoor expansion valve of the liquid refrigerant pipe, and the control device fully closes the electromagnetic valve based on a stop command for each indoor unit or a fully closed control signal for the indoor expansion valve. This is a characteristic configuration.

  That is, the first aspect is made in view of the fact that the indoor units that are individually stopped in the multi-type air conditioner that is operating in the cooling mode can be determined by the stop command of each indoor unit or the fully closed control signal of the indoor expansion valve. Is. That is, when the operation of one indoor unit is stopped in the cooling mode, a stop command for the indoor unit is input, and based on this, the indoor expansion valve corresponding to the indoor unit is fully closed. Since the solenoid valve is fully closed in accordance with this, even if high-pressure liquid refrigerant is supplied from the outdoor unit to the indoor unit, it is blocked by the solenoid valve. As a result, the pressure of the liquid refrigerant on the inlet side of the indoor expansion valve is reduced, so that the amount of liquid refrigerant flowing into the heat exchanger of the indoor unit can be greatly reduced even if the indoor expansion valve is poorly closed. Therefore, it is possible to avoid the problem that the components arranged around the heat exchanger of the indoor unit are condensed, and the condensed water falls to contaminate the room.

  Further, the second aspect of the present invention is configured by branching from a gas refrigerant pipe and a liquid refrigerant pipe of one outdoor unit and connecting a plurality of indoor units in parallel. An expansion valve is provided, and the corresponding indoor expansion valve is fully closed based on a stop command for each indoor unit in the cooling mode, and the corresponding indoor expansion valve is fixed based on the stop command for each indoor unit in the heating mode. In the multi-type air conditioner provided with a control device that controls to maintain a small opening of the electromagnetic valve, an electromagnetic valve is provided on the outdoor unit side of the liquid refrigerant pipe of the indoor unit relative to the indoor expansion valve. A check valve is provided that bypasses the electromagnetic valve and permits the flow of liquid refrigerant only from the indoor unit side to the outdoor unit side, and the control device is based on a stop command for each indoor unit. Wherein constituting the said solenoid valve is fully closed Te.

  That is, in the second mode, the indoor units that are individually stopped in the operating multi-type air conditioner can be determined by the stop command of each indoor unit in both the cooling mode and the heating mode. However, in the heating mode, even if a stop command for the indoor unit is input, the indoor expansion valve is not fully closed, but is kept at a constant minute opening, and a small amount of refrigerant is circulated so that the indoor heat exchange In this way, refrigerant and refrigerating machine oil are prevented from collecting.

  Therefore, when the solenoid valve is fully closed by the stop command for the indoor unit, a check valve is provided to bypass the solenoid valve, ensuring a small amount of refrigerant circulation in the heating mode, and the heat exchanger Return the refrigerant and refrigeration oil to the outdoor unit. In the second mode, the same operation as in the first mode is performed in the cooling mode.

  In the second aspect, a capillary tube can be provided by connecting the liquid refrigerant pipe closer to the outdoor unit than the solenoid valve and the gas refrigerant pipe of the indoor unit. According to this, even if the check valve malfunctions, the heat exchanger of the indoor unit can be bypassed to return the refrigerant and the refrigerating machine oil to the outdoor unit. In the cooling mode, the refrigerant circulated to the stopped indoor unit is returned to the outdoor unit through the capillary tube.

  Further, an electromagnetic valve unit corresponding to the first aspect of the present invention includes an electromagnetic valve having a pair of pipe joints that can be inserted and connected to the liquid refrigerant pipe, a power supply terminal to which power to drive the electromagnetic valve is supplied, An auxiliary relay that opens the b contact inserted in the drive circuit of the solenoid valve and an excitation power supply terminal to which an excitation current for driving the auxiliary relay is supplied are housed in a housing, and the multi-type air conditioner It is provided corresponding to each indoor unit, and an excitation current can be supplied to the excitation power supply terminal based on a cooling mode operation command of the corresponding indoor unit.

  An electromagnetic valve unit corresponding to the second aspect of the present invention includes an electromagnetic valve having a pair of pipe joints that can be inserted and connected to liquid refrigerant piping, a check valve connected in parallel to the electromagnetic valve, and the electromagnetic valve. A power supply terminal to which power for driving the valve is supplied; an auxiliary relay for opening the contact b inserted in the drive circuit of the solenoid valve; and an excitation power supply terminal to which an excitation current for driving the auxiliary relay is supplied. It is housed in a housing and is provided corresponding to each indoor unit of the multi-type air conditioner, so that an excitation current can be supplied to the excitation power supply terminal when the corresponding indoor unit is operated.

  According to the solenoid valve unit of the present invention, the indoor unit can be provided outside the outdoor unit, and the indoor unit when the cooling operation is stopped can be reduced even if the indoor expansion valve closes down without modifying or redesigning the indoor unit. It is possible to prevent liquid refrigerant from flowing into the heat exchanger of the unit.

  According to the present invention, in the multi-type air conditioner operating in the cooling mode, even if the closeability of the indoor expansion valve is reduced, the liquid refrigerant is prevented from leaking into the heat exchanger of the stopped indoor unit. be able to.

Hereinafter, the present invention will be described based on embodiments.
(Embodiment 1)
The block block diagram of the multi-type air conditioner of one Embodiment which applied the 2nd aspect of this invention to FIG. 1, FIG. 2 is shown. Note that FIG. 1 shows the refrigerant flow in the cooling mode by arrows, and FIG. 2 shows the refrigerant flow in the heating mode by arrows. In FIG. 3, the cross section of one Embodiment of an indoor expansion valve is shown with the schematic diagram.

  As shown in FIGS. 1 and 2, the multi-type air conditioner of the present embodiment is configured to have one outdoor unit 1 and a plurality of indoor units 2 (for example, a, b, c). The outdoor unit 1 is configured by connecting a compressor 3, a four-way valve 4, an outdoor heat exchanger 6 including an outdoor blower 5, and an accumulator 7 with refrigerant piping. Each indoor unit 2 (a, b, c) is configured in the same manner, and includes an indoor heat exchanger 12 having an indoor blower 11, an indoor expansion valve 13 using an electronic expansion valve, and an indoor expansion valve 13. A strainer 14 provided at the entrance / exit is connected by a refrigerant pipe. Further, the gas refrigerant pipes 15 and the liquid refrigerant pipes 16 of the plurality of indoor units 2 (a, b, c) are provided in parallel by branching from the gas refrigerant pipe 8 and the liquid refrigerant pipe 9 of the outdoor unit 1.

  A feature of this embodiment is that an electromagnetic valve unit 17 is inserted into the liquid refrigerant pipe 16 of the indoor unit 2 (a, b, c). The electromagnetic valve unit 17 of the present embodiment includes an electromagnetic valve 18 having a pair of pipe joints that can be inserted and connected to the liquid refrigerant pipe, and an electromagnetic valve 18 connected in parallel to the electromagnetic valve 18 so that the liquid refrigerant is only transferred from the indoor unit 2 side to the outdoor unit 1 side. A check valve 19 that allows flow, a short pipe 20 that has a pair of pipe joints that can be inserted and connected to the gas refrigerant pipe, and a liquid refrigerant pipe that is downstream of the short pipe 20 and the allowable flow of the check valve 19 communicate with each other. And a capillary tube 21 provided in the housing 22 and housed in a housing 22. The opening degree of the indoor expansion valve 13 and the electromagnetic valve 18 is controlled by a control device (not shown) provided in each indoor unit 2 (a, b, c).

  Next, the operation of the embodiment configured as described above will be described.

  The basic operation will be described. In the cooling mode, the gas refrigerant discharged from the compressor 3 is condensed in the outdoor heat exchanger 6 via the four-way valve 4 and corresponds to each indoor unit 2 from the liquid refrigerant pipe 9. The liquid refrigerant pipe 16, the electromagnetic valve 18, the strainer 14, and the indoor expansion valve 13 are supplied to the indoor heat exchanger 12. The liquid refrigerant is decompressed and expanded into a two-phase refrigerant of liquid and gas by the indoor expansion valve 13 and supplied to the indoor heat exchanger 12, and the indoor air circulated by the indoor blower 11 is cooled and evaporated, The gas refrigerant pipe 15 passes through the short pipe 20 of the electromagnetic valve unit 17, and then returns from the gas refrigerant pipe 8 of the outdoor unit 1 to the compressor 3 through the four-way valve 4 and the accumulator 7.

  As described above, when all the indoor units 2 (a, b, c) are operated in the cooling mode, the electromagnetic valve 18 is fully opened, and the indoor expansion valve 13 is set according to the set temperature of each indoor unit 2 or the like. The opening degree is controlled, and the room temperature is adjusted by adjusting the flow rate of the two-phase refrigerant flowing through the indoor heat exchanger 12. Here, for example, as shown in FIG. 3, the indoor expansion valve 13 is configured such that a valve body 13b is detachably disposed on a valve seat 13a having an opening, and the valve body 13b is moved up and down by an electronic drive unit 13c. The opening of the gap between the seat 13a and the valve body 13b is controlled. In general, when the operation of the indoor unit 2 is stopped in the cooling mode, the valve body 13b is brought into close contact with the seat surface of the valve seat 13a to prevent the refrigerant from flowing into the indoor heat exchanger 12, and Avoid air cooling.

  By the way, the refrigerant circulating in the refrigeration cycle is contaminated with foreign matter such as wear powder generated by compressor operation, dust generated and mixed during pipe connection work, or flux generated when piping is brazed. Therefore, for example, a strainer 14 of about 100 mesh is provided and collected at the entrance / exit of the indoor expansion valve 13 so that the foreign matter does not get caught in the gap between the valve body 13b of the indoor expansion valve 13 and the valve seat 13a.

  However, fine foreign matter that cannot be captured by the strainer 14 may bite into the gap between the valve body 13b and the valve seat 13a that are opened and closed, and the gap may remain even when the indoor expansion valve 13 is fully closed. In addition, the biting of foreign matter may leave scratches on the seat surface of the valve seat 13a, and the closing performance of the indoor expansion valve 13 may deteriorate.

  On the other hand, in the multi-type air conditioner of the present embodiment, each indoor unit 2 is controlled to be individually operated or stopped based on the judgment of the user, and when all the indoor units 2 are operated in the cooling mode. When the indoor unit 2 is individually stopped, when the stop command for the indoor unit 2 is input, the indoor expansion valve 13 is fully closed to prevent the refrigerant from flowing through the indoor heat exchanger 12.

  However, if the closing performance of the indoor expansion valve 13 is reduced, even if the indoor expansion valve 13 is fully closed when the operation of the indoor unit 2 is stopped, other indoor units are still in operation. The high-pressure liquid refrigerant exists on the liquid refrigerant inlet side of the indoor expansion valve 13. Therefore, the high-pressure liquid refrigerant leaks from the gap between the valve body 13b and the valve seat 13a and flows into the indoor heat exchanger 12. As described above, when the liquid refrigerant leaks into the indoor heat exchanger 12 of the stopped indoor unit 2, the ambient air of the indoor heat exchanger 12 is cooled, and natural convection of the ambient air is generated. Condensation may occur on the parts placed in the room, and the condensed water may fall from the indoor unit 2 to contaminate the room.

  Therefore, in the present embodiment, when a stop command is input to an individual indoor unit 2 (for example, 2a) from a remote controller or the like in an operating multi-type air conditioner regardless of the cooling mode or the heating mode, The liquid refrigerant is prevented from leaking into the indoor heat exchanger 12 of the stopped indoor unit 2a by fully closing the valve 18.

  On the other hand, in the heating mode, as shown in FIG. 2, the high-pressure and high-temperature gas refrigerant discharged from the compressor 3 is the four-way valve 4, the gas refrigerant pipe 8, the short pipe 20 of the electromagnetic valve unit 17, the indoor unit 2. Is introduced into the indoor heat exchanger 12 through the gas refrigerant pipe 15 and heated by exchanging heat with room air. The liquid refrigerant condensed in the indoor heat exchanger 12 is led to the outdoor heat exchanger 6 through the liquid refrigerant pipe 16, the indoor expansion valve 13, the electromagnetic valve 18, and the liquid refrigerant pipe 9 to evaporate, and the evaporated gas refrigerant. Is returned to the compressor 3 via the four-way valve 4 and the accumulator 7.

  By the way, in general, in the heating mode, even if an individual stop command is input to the indoor unit 2, the indoor expansion valve 13 is not fully closed, and is kept at a constant minute opening, and a small amount of refrigerant is circulated. Thus, refrigerant and refrigerating machine oil are prevented from collecting in the indoor heat exchanger 12.

  However, if the solenoid valve 18 is fully closed based on the individual stop command for the indoor unit 2 as in this embodiment, the refrigerant and the refrigerating machine oil in the indoor heat exchange 12 are not returned to the outdoor unit 1. Therefore, in this embodiment, even if the electromagnetic valve 18 is fully closed, the refrigerant and the refrigeration oil in the indoor heat exchanger 12 are returned to the outdoor unit 1 through the check valve 19.

Further, in the present embodiment, assuming that the check valve 19 may malfunction due to some reason, the liquid refrigerant pipe 16 and the gas refrigerant pipe 15 (short pipe 20) on the downstream side of the electromagnetic valve 18 are communicated. Thus, the capillary tube 21 is provided to ensure a bypass flow path.
(Embodiment 2)
Although not shown, an embodiment of the first aspect of the present invention will be described next.

  The present embodiment is characterized in that the electromagnetic valve 18 is closed based on a fully closing command for the indoor expansion valve 13. That is, in the heating mode, even if the indoor unit 2 is stopped, the indoor expansion valve 13 is kept at a very small opening degree to ensure the circulation of the refrigerant and the refrigerating machine oil. In this case, the electromagnetic valve 18 is opened. It is preferable to leave it open. Therefore, in view of the fact that the indoor expansion valve 13 is fully closed only when the indoor unit 2 is stopped in the cooling mode, the electromagnetic valve 18 is fully closed based on the full close command of the indoor expansion valve 13. It is. In this case, the check valve 19 and the capillary tube 21 shown in FIGS.

  Moreover, the structural example of the solenoid valve unit 17 used for this embodiment is shown in FIG. In the figure, the power of the electromagnetic valve 18 is received from the power terminal block 31 of the indoor unit 2. During the cooling operation of the indoor unit 2, a cooling operation signal is output from the port 32 of the printed board of the indoor unit 2, and the auxiliary relay 33 is excited. As a result, the b contact (non-excited closed circuit) 33b of the auxiliary relay 33 is opened, the excitation of the solenoid valve 18 is cut off, and the solenoid valve 18 is opened. On the other hand, when a stop command is input to the indoor unit 2, the cooling operation signal is not output from the port 32, the auxiliary relay 33 is de-energized, the b contact is closed, and the solenoid valve 13 is closed. Thereby, liquid refrigerant can be prevented from leaking into the indoor heat exchanger 12 of the stopped indoor unit 2.

  In the above embodiment, the example in which the electromagnetic valve unit 17 is provided separately from the casing of the indoor unit 2 has been described. However, the present invention is not limited thereto, and the electromagnetic valve unit 17 is accommodated in the casing of the indoor unit 2. You can also. In this case, a separate housing for housing the solenoid valve unit 17 is not necessary.

It is a block block diagram of the multi type air conditioner of one Embodiment to which this invention is applied, and is a figure which shows the flow of the refrigerant | coolant at the time of cooling. It is a figure which shows the flow of the refrigerant | coolant at the time of heating of one Embodiment of FIG. It is a section lineblock diagram of an example of an indoor expansion valve. It is a circuit block diagram of one Embodiment of a solenoid valve unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outdoor unit 2 Indoor unit 8, 15 Gas refrigerant piping 9, 16 Liquid refrigerant piping 12 Indoor heat exchanger 13 Indoor expansion valve 14 Strainer 18 Electromagnetic valve 19 Check valve 20 Short tube 21 Capillary tube

Claims (7)

Branched from a gas refrigerant pipe and a liquid refrigerant pipe of one outdoor unit, a plurality of indoor units are connected in parallel, and an indoor expansion valve is provided in the liquid refrigerant pipe of each indoor unit. In a multi-type air conditioner comprising a control device for fully closing the corresponding indoor expansion valve based on a unit stop command,
An electromagnetic valve is provided on the outdoor unit side of the indoor expansion valve of the liquid refrigerant pipe of each indoor unit,
The said control apparatus fully closes the said electromagnetic valve based on the stop command of each indoor unit, or the fully-closed control signal of the said indoor expansion valve, The multi-type air conditioner characterized by the above-mentioned. Branched from a gas refrigerant pipe and a liquid refrigerant pipe of one outdoor unit, a plurality of indoor units are connected in parallel, and an indoor expansion valve is provided in the liquid refrigerant pipe of each indoor unit. The corresponding indoor expansion valve is controlled to be fully closed based on a unit stop command, and the corresponding indoor expansion valve is controlled to be held at a certain minute opening based on the stop command for each indoor unit in the heating mode. In a multi-type air conditioner comprising a control device,
Provide an electromagnetic valve on the outdoor unit side of the indoor expansion valve of the liquid refrigerant pipe of each indoor unit, and allow the liquid refrigerant to flow only from the indoor unit side to the outdoor unit side by bypassing the electromagnetic valve A check valve is installed,
The control device fully closes the solenoid valve based on a stop command for each indoor unit. The multi-type air conditioner according to claim 2,
A multi-type air conditioner, wherein a capillary tube is provided by connecting the liquid refrigerant pipe closer to the outdoor unit than the electromagnetic valve and the gas refrigerant pipe of the indoor unit.   A solenoid valve having a pair of pipe joints that can be inserted into and connected to the liquid refrigerant pipe, a power supply terminal to which power to drive the solenoid valve is supplied, and an auxiliary to drive open the b contact inserted in the drive circuit of the solenoid valve A relay and an excitation power supply terminal to which an excitation current for driving the auxiliary relay is supplied are housed in a housing, provided corresponding to each indoor unit of the multi-type air conditioner, and a cooling mode of the corresponding indoor unit An electromagnetic valve unit configured to supply an excitation current to the excitation power supply terminal based on the operation command.   A solenoid valve having a pair of pipe joints that can be inserted into and connected to the liquid refrigerant pipe; a check valve connected in parallel to the solenoid valve; a power supply terminal that supplies power to drive the solenoid valve; and The auxiliary relay that opens the b contact inserted in the drive circuit and the excitation power supply terminal to which the excitation current that drives the auxiliary relay is supplied are housed in a housing, and each indoor unit of the multi-type air conditioner A solenoid valve unit provided correspondingly and configured to supply an excitation current to the excitation power supply terminal during operation of the corresponding indoor unit. In the solenoid valve unit according to claim 5,
A short tube having a pair of pipe joints that can be inserted and connected to the gas refrigerant pipe; and a capillary tube provided by communicating the short pipe and the liquid refrigerant pipe on the downstream side of the allowable flow of the check valve; Is a solenoid valve unit that is housed in the housing. The solenoid valve unit according to claim 4,
The power terminal is connected to a power terminal block of a corresponding indoor unit,
The solenoid valve unit, wherein the excitation power supply terminal is connected to an output signal port of a cooling mode operation signal of the indoor unit of a control board constituting a control device of the corresponding indoor unit.

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