JPH01181043A - Air conditioner - Google Patents

Abstract

PURPOSE:To shorten the exciting time of a solenoid valve by providing the air conditioner with a pipeline temperature detector and a pipeline temperature switch, and further with a control circuit in which an external air temperature switch actuating a solenoid valve and the pipeline temperature switch are connected in series. CONSTITUTION:When a space heating operation is started, a pipeline temperature thermo-unit 28 is turned on, and an external air temperature is lowered, an external air temperature switch 25 is set on the low temperature side, and a solenoid valve 11 is excited, a gas coolant is injected to a compressor 1 through an injection circuit. When the external air temperature becomes high, the external air temperature switch 25 is set on the high temperature side, and the solenoid valve 11 is deenergized, thus the injection is stopped. When the room temperature rises up a room temperature thermostat 20 is turned off, a compressor relay 18 is deenergized and an outdoor motor 21 is stopped. Further, a constant close contact 19 of the compressor relay 18 is turned on, and power is supplied to a crankcase heater 17 and the solenoid valve 11 is excited through a pipeline temperature thermo-unit 28 and the external air temperature switch 25. When the pipeline temperature rises up, the pressure within the system is balanced, and the pipeline temperature thermo-unit 28 is turned off to deenergize the solenoid valve 11.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an air conditioner equipped with a compressor for an engine.

BACKGROUND OF THE INVENTION In recent years, air conditioners have been using an injection method in which a portion of the refrigerant in the expansion process is recovered by a compressor in order to improve performance during heating operations at low outside temperatures.

An example of the conventional air conditioner mentioned above will be described below with reference to the drawings.

FIGS. 3 and 4 show a refrigeration cycle of a conventional air conditioner and a control circuit for controlling the refrigeration cycle μ. In FIG. 3, reference numeral 1 denotes a variable capacity compressor, and the refrigerant discharged by the compressor 1 enters the outdoor heat exchanger 3 via the four-way valve 2 and is heated by the outdoor fan 4. An exchange takes place. Next, the refrigerant flows into the gas-liquid separator 6 via the pressure reducing device 6, and the refrigerant that has entered in the gas-liquid two-phase state is separated into gas and liquid, and the liquid refrigerant is passed through the indoor heat exchanger 8 to the indoor fan. 9 to exchange heat. The refrigerant that has entered the indoor heat exchanger 8 enters the suction port of the compressor 1 via the four-way valve 2, forming a refrigeration cycle. Reference numeral 10 denotes an injection circuit, which injects the gas refrigerant separated by the gas-liquid separator e into the injection port 12 of the compressor 1 by operating the solenoid valve 11.

FIG. 4 shows a control circuit for an air conditioner that controls the refrigeration cycle described above. 13, 14, 15 are the R phase of the three-phase power supply,
An operation switch 16 is provided on one line 13 of the S phase and T phase, and an excitation switch 16 is provided between the two lines 13 and 14 by a crankcase 17 for keeping the compressor 1 warm and a compressor relay 18. A series circuit with a normally closed contact 19 is connected. 20 is a room temperature thermostat for detecting the room temperature, and a compressor relay 18 and an outdoor motor 2 are connected in series with this room temperature thermostat 20.
1 parallel circuit is connected. 22 is a heating/cooling changeover switch, which is connected in series with the four-way valve 2.

23 is an indoor motor that drives the indoor fan 9.

Furthermore, compressed pus 1 is connected to the three-phase power supply 13, 14, 15 via a normally open contact 24 of a compressor relay 18. 26 is an outside temperature switch having a low temperature side contact 26 and a high temperature side contact 27, and is connected in series with the solenoid valve 11 that controls injection. Also, this outside temperature switch 26
The hot side contact 27 of is connected in parallel to the series circuit of the normally closed contact 19 of the crankcase heater 17 and the compressor relay 18, and the cold side contact 26 is connected to the power line 14.

The operation of the air conditioner configured as above will be described below.

First, when starting heating operation, the room temperature is usually low and the room temperature thermometer is set to 2o.
is turned on, and in this state, when the operation switch 1e and the cooling/heating switch 22 are turned on, the four-way valve 2 and the compressor relay 18 are energized, and this normally open contact 24 is turned on, and the L compressor 1 is driven. do. At the same time, the normally closed contact 19 of the compressor relay 18 is set to 0FFj, and the crankcase heater 17 is no longer energized. Next, when the outside temperature is low, for example below 5° C., the outside temperature switch 25 is set to the low temperature side and the solenoid valve 11 is energized. By energizing this electromagnetic valve 11, the gas refrigerant separated by the gas-liquid separator 6 is injected into the injection port 12 of the compressor 1 via the injection circuit 1o. Next, when the outside temperature rises, the outside temperature switch 26 is set to the high temperature side, and the stain valve 11 is demagnetized, injection is stopped, and normal capacity operation is resumed. In this way, the injection circuit can be turned ON-OFF depending on the outside temperature. Furthermore, if the room temperature rises while the outside temperature is high and the outside temperature switch 26 is on the high temperature side, and the room temperature thermometer 2o is turned off,
The compressor relay 18 is demagnetized and the outdoor motor 21 is stopped. When the compressor relay 18 is demagnetized, its normally open contact 24 is turned off and the compressor is stopped. When the compressor 1 is stopped, the pressure in the system is balanced between the high pressure side and the low pressure side, so the solenoid valve 11 has a high refrigerant pressure on the injection port 12 side, although for a short time.
Since the pressure becomes lower at the side, a back pressure is applied to the valve seat (not shown) inside the solenoid valve 11, causing an abnormal "click, click" sound. In order to prevent this abnormal noise, when the compressor 1 is stopped while the outside temperature switch 26 is on the high temperature side, the normally closed contact 19 of the compressor relay 18 is turned ON L and the solenoid valve 11 is forcibly energized. By forcibly opening the solenoid valve 11 regardless of the outside temperature, abnormal noise due to the back pressure applied to the solenoid valve 11 is prevented.

Problems to be Solved by the Invention However, in the above configuration, the outside temperature switch 2
6 is on the high temperature side and the compressor 1 is stopped, the solenoid valve 11 is closed regardless of the pressure balance in the system.
is constantly excited, so after the pressure in the system is balanced, unnecessary power is consumed by the solenoid valve 11,
Furthermore, there is a problem in that the durability of the solenoid valve 11 is impaired due to the extension of the excitation time.

In view of the above problems, the present invention aims to save energy and shorten the excitation time by installing a solenoid valve in the injection circuit that occurs during pressure balance in the system when the room temperature thermostat is turned off and the compressor is stopped. The present invention provides an air conditioner equipped with a control circuit that demagnetizes the system after the pressure is balanced.

Means for Solving the Problems In order to solve the above problems, the air conditioner of the present invention includes a pipe temperature detector that detects the pipe temperature of the outdoor heat exchanger using an injection circuit that turns 0N7OFF using a solenoid valve; The piping temperature detector includes a switch that detects a predetermined temperature and operates the valve, and a switch that operates the solenoid valve and a switch that causes the piping temperature detector to detect a predetermined temperature and operate the valve are connected in series. It has a configuration.

Effect The present invention has the above-described configuration, so that the compressor relay is set to 0FFI in order to prevent abnormal noise due to the back pressure applied to the solenoid valve.
When the compressor stops, the normally closed contact of the compressor relay turns on, and the solenoid valve connected to it and forcibly excited detects the pressure balance depending on the piping temperature and adjusts the pressure balance. After detection, the solenoid valve will be demagnetized.

EXAMPLE Hereinafter, an air conditioner according to an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a control circuit for an air conditioner according to an embodiment of the present invention. In Figure 1, 1 is a compressor, 2
is a four-way valve, 13, 14, 15 is the R phase, S phase and T phase of the three-phase power supply, 16 is the operation switch, 17 is the crankcase heater, 18 is the compressor relay, 19 is the normally closed contact of the compressor relay, 20 is a room temperature thermometer, 21 is an outdoor motor, 22 is a cooling/heating switch, 23 is an indoor motor, 24 is a normally open contact of the compressor relay 18, 26 is an outside temperature switch having a low temperature side contact 26 and a high temperature side contact 27, The above configuration is the same as the configuration shown in FIG. 4, and detailed explanation will be omitted.

Reference numeral 28 denotes a pipe length thermo unit, which includes a pipe temperature detector 29 for detecting pipe temperature, and a pipe temperature switch 3o for operating when the pipe temperature detector detects a predetermined temperature. A solenoid valve 11, a pipe length thermostat unit 28, and an outside temperature switch 26 are connected in series between the two wires 13 and 14 of the three-phase power supply.

The operation of the air conditioner configured as described above will be explained below with reference to FIGS. 1 and 2.

First, FIG. 2 shows changes over time in the pipe temperature and the pressure applied to the solenoid valve for injection control after the compressor is stopped. Assuming that the compressor stops at a time of 0 seconds, a positive pressure is applied to the solenoid valve immediately after that, but the pressure decreases as time passes, and becomes a reverse pressure after t1 seconds. Then, the pressure within the system is gradually balanced, and after t2 seconds, the pressure is completely balanced.

On the other hand, during heating operation, the pipe temperature is lower than the outside air temperature T2°C. It rises when the compressor stops, reaches T1°C after t2 seconds when the pressure balance in the system is completely balanced, and thereafter gradually approaches the outside air temperature T2°C. As shown in this figure, there is a correlation between the pressure applied to the solenoid valve for injection control and the pipe temperature, and by detecting the pipe temperature T4°C, the pressure balance in the system can be detected. .

The operation shown in FIG. 1 will be explained. First, when heating operation is started, the room temperature is usually low and the room temperature thermometer 20 is turned on.

In this state, when the operation switch 16 and the cooling/heating switch 22 are turned on, the four-way valve 2 and the compressor relay 18 are excited, and the indoor motor 23 and the outdoor motor 21 are driven. When the compressor relay 18 is energized, the normally open contact 24 is turned ON and the L compressor 1 is driven. At the same time, the normally closed contact 19 of the compressor relay 18
is turned off, and the crankcase heater 17 is no longer energized. When heating operation is started in this way, the pipe temperature becomes T
.

℃ or less, and the pipe length thermo unit 28 will be interrupted.

Next, when the outside temperature is low, for example below 6°C, the outside temperature switch 25 is turned to the low temperature side, and the pipe length thermo unit 2 is turned off.
The solenoid valve 11 is energized via the solenoid valve 8 . By energizing this electromagnetic valve 11, the gas refrigerant separated by the gas-liquid separator 6 is injected into the injection port 12 of the compressor 1 via the injection circuit 10. When the outside temperature becomes high, the outside temperature switch 26 is set to the high temperature side, the solenoid valve 11 is demagnetized, and the injection is stopped. In this way, the outside temperature switch 26 is set to 0N-
The injection circuit 10 is controlled by turning it off. In addition, when the outside temperature is high and the outside temperature switch 26 is on the high temperature side, the room temperature rises and the room temperature thermometer 2o is set to 0.
When it is FF, the compressor relay 18 is demagnetized and the outdoor motor 21 is stopped. When the compressor relay 18 is demagnetized, its normally open contact 24 is turned off and the compressor is stopped. In addition, the normally closed contact 19 of the compressor relay 18 is turned ON, energizing the crankcase heater 1, and the solenoid valve 11 is energized via the pipe temperature thermostat unit 28 and the outside temperature switch 26. Then, the pipe temperature gradually rises,
When the pressure within the system is balanced and the pipe temperature reaches 11° C., the pipe temperature thermostat unit 28 is turned off and the L solenoid valve 11 is demagnetized.

As described above, according to this embodiment, the solenoid valve allows 0N-OFF.
By connecting a piping temperature thermostat unit that detects piping temperature in series with the outside temperature switch that activates the solenoid valve in the injection circuit, it is possible to prevent abnormalities in the solenoid valve due to pressure balance in the system when the compressor is stopped. The excitation time of the electromagnetic valve that is excited to prevent noise can be shortened, and as a result, the power consumption of the control circuit can be reduced and deterioration of the electromagnetic valve can be delayed.

In this embodiment, the behavior due to ON-OFF of the room temperature thermostat 32 has been described, but when the operation switch 16 is ON-OFF,
A similar effect can be obtained with FF.

Effects of the Invention As described above, the present invention is an injection circuit that turns ○N-OFF using a solenoid valve, and includes a pipe temperature detector that detects the pipe temperature of the outdoor heat exchanger, and the pipe temperature detector that detects a predetermined temperature. By providing a control circuit that connects in series the outside temperature switch that operates the solenoid valve and the piping temperature switch that operates the solenoid valve, abnormal noises of the solenoid valve due to pressure balance in the system can be suppressed. By demagnetizing the solenoid valve that has been energized to prevent this problem once the pressure is balanced and shortening the energization time of the solenoid valve, it is possible to reduce the power consumption of the control circuit and delay the deterioration of the solenoid valve. can.

[Brief explanation of the drawing]

Fig. 1 is a control circuit diagram of an air conditioner showing an embodiment of the present invention, Fig. 2 is a characteristic diagram showing pressure balance in the system and changes in piping temperature over time, and Fig. 3 is a refrigeration cycle according to a conventional example. 4 are control circuit diagrams of an air conditioner showing a conventional example. 1... Compressor, 2... Four-way valve, 3...
... Outdoor heat exchanger, 5 ... Pressure reduction device, 8
... Indoor heat exchanger, 11 ... Solenoid valve, 1o ... Injection circuit, 29 ...
...Piping temperature detector, 30...Piping temperature switch, 26...Outside temperature switch. Name of agent: Patent attorney Toshio Nakao and 1 other person! −
Pressure device 2 - wt valve 3 -.../) lll Fever genitalia - - Intimidation device 8 - Indoor @ heat exchange Todoroki IO - Injikushi 1 So H - 11 Electric Isoui 25 - Outside temperature switch 29-1 Piping Temperature Test 30--Piping Temperature Switch 1 Fig. 1'' 6 Fig. 2 Fig. 2 Volume [Second J Fig. 3]

Claims (1)

[Claims] A compressor for injection, a four-way valve, an outdoor heat exchanger, a pressure reducing device, and an indoor heat exchanger are connected in sequence, and a refrigeration cycle is constructed in which an injection circuit having a solenoid valve is connected to the compressor, and the outdoor side A pipe temperature detector that detects the pipe temperature of the heat exchanger, a pipe temperature switch that operates when the pipe temperature detector detects a predetermined temperature, and an outside temperature switch that operates the solenoid valve, An air conditioner characterized by comprising a control circuit connected in series with a switch.