JP3199403B2 - Air sensor pressure sensor destruction prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the destruction of a pressure sensor due to an abnormally high pressure generated by a liquid ring when an outdoor unit of an air conditioner equipped with a low-pressure scroll compressor is heated in a state where a three-way valve is closed in winter. The present invention relates to a device for preventing the occurrence of stagnation.

[0002]

2. Description of the Related Art In recent years, there has been a trend toward lower noise in a separation type air conditioner, and a compressor which is a noise source of a product is being changed from a rotary compressor to a scroll compressor, thereby reducing the size of the product. For this reason, low-pressure scroll compressors that do not require an accumulator are often used. In addition, in order to respond to the air conditioning load in detail by changing the amount of circulating refrigerant by an inverter, the frequency of the inverter is controlled by the refrigerant pressure to realize more efficient operation.

A configuration of a refrigeration cycle of this type of conventional separation type air conditioner will be described with reference to FIG.

As shown in the figure, a low-pressure scroll compressor 103 driven by an inverter 102 and a four-way valve 10 for switching a flow path of a refrigerant are provided inside an outdoor unit 101.
4. An outdoor heat exchanger 105 and an electric expansion valve 106 of a refrigerant throttle mechanism are provided. A pressure connected via a capillary tube 109 to a pipe 108 capable of detecting a suction pressure during cooling and detecting a discharge pressure during heating. Sensor 110
The frequency is determined so as to keep the detected pressure constant. In addition, an operation command from the indoor unit 107 is transmitted through the signal line 1.
13 to the inverter 102 and the inverter 10
2, the low-pressure scroll compressor 103 is driven, and the refrigerant discharged from the low-pressure scroll compressor 103 passes through a discharge pipe 111 derived from the low-pressure scroll compressor 103.
Via the four-way valve 104, the cooling is performed by the outdoor heat exchanger 105 during cooling, and the heating is performed by the indoor unit 107, and the pressure is reduced by the electric expansion valve 106. Through the indoor unit 10
7, and at the time of heating through the gas side three-way valve 116,
The heat is exchanged as an evaporating action in the outdoor heat exchanger 105,
A refrigeration cycle is formed in which cooling is performed via the gas side three-way valve 116 during heating, and heating is performed via the liquid side three-way valve 115 and then returns to the low-pressure scroll compressor 103 via the suction pipe 112.

In the above configuration, the indoor unit 10
The operation command from the inverter 7 is transmitted via the signal line 113 to the inverter 10.
2, and the detected pressure of the pressure sensor 110 is sent to the inverter 102 via a signal line 114. The inverter 102 detects the air-conditioning load of the indoor unit 107 and the detection value of the pressure sensor 110 so that the suction pressure during cooling is: In addition, the operating frequency of the low-pressure scroll compressor 103 is determined so that the discharge pressure becomes the optimum condition during heating.

[0006]

In such a conventional refrigeration cycle control, the liquid side three-way valve 115 is not connected during the trial operation when the air conditioner is installed without connecting the indoor unit 107.
When the outdoor unit 101 is operated alone with the gas side three-way valve 116 closed without opening, the pump is down in the case of cooling operation, so that abnormal pressure rise does not occur.
When the heating operation is performed in winter, the discharge gas is supplied to the four-way valve 10.
4, a gas side three-way valve 116 is reached, and the pressure sensor 110 detects the four-way valve 104 and the gas-side three-way valve 11 during the heating operation.
6, the discharge pressure is detected. At this time, since the compressor is a low-pressure can,
Instead of discharging the gas after cooling the windings in the compressor can as in a high-pressure can compressor, the discharged gas is immediately discharged from the discharge valve to the discharge pipe 111. If the compressor is a high-pressure can compressor, the compressor body serves as a buffer, but since there is no buffer portion, the discharged gas rapidly increases in pressure between the discharge pipe 111 and the gas-side three-way valve 116, Since the atmospheric temperature is low in winter, the pressure reaches the saturation pressure and liquefies in a short time. When all of the discharged gas is liquefied in this way, the gas is in a liquid-sealed state, and the liquid is compressed by the compression of the low-pressure scroll compressor 103, and is instantaneously 10 MPa (100 kg / cm ² ).
As a result, the pressure rises more rapidly than before the scroll compressor 103 stopped even though the pressure sensor 110 must detect the pressure and stop the scroll compressor 103. That is, there is a problem that the pressure sensor 110 is destroyed because the pressure rises instantaneously before the pressure sensor 110 detects the pressure instantaneously.

[0007] The present invention solves the above-mentioned problems, and in an air conditioner equipped with a low-pressure scroll compressor, prevention of destruction of a pressure sensor during a winter heating test run when a liquid-side three-way valve and a gas-side three-way valve are closed. It is an object.

[0008]

In order to achieve the above object, the present invention provides an inverter for controlling an inverter, a low-pressure scroll compressor controlled by the inverter, and a discharge pipe derived from the low-pressure scroll compressor. ,
A suction pipe, a refrigerant flow switching four-way valve, an outdoor heat exchanger, a pressure control pressure sensor, a liquid-side three-way valve and a gas-side three-way valve for connection to an indoor unit, and a gas-side union. A pressure sensor is provided between the gas-side three-way valve and the gas-side union so that abnormal pressure is not applied to the pressure sensor during a heating trial run.

[0009]

According to the present invention, when the outdoor air temperature is low in winter, the gas-side three-way valve and the gas for indoor connection are used during the trial run of the outdoor unit alone with the liquid-side three-way valve and the gas-side three-way valve closed. Since the pressure sensor is installed between the side unions, the discharge pressure is applied to the pressure sensor for the first time by opening the gas side three-way valve. By preventing the discharge pressure of the compressor from being applied to the sensor, it is possible to prevent the pressure sensor from being affected even if an abnormally high pressure due to liquid sealing occurs.

[0010]

An embodiment of the present invention will be described below with reference to FIG. Note that the same reference numerals as those shown in the conventional example indicate the same items, and description thereof will be omitted.

That is, as shown in FIG. 1, the gas-side union 1 is located between the gas-side three-way valve 116 and the indoor unit 107.
Is provided on the side wall of the outdoor unit 101, and the gas-side three-way valve 11 is provided.
The capillary tube 109 derived from the pressure sensor 110 is connected between the pressure sensor 6 and the gas-side union 1.

In the above configuration, in the winter, the liquid-side three-way valve 11
5 and the heating test operation with the gas side three-way valve 116 closed, the inverter 1
02 issues a driving command to the low-pressure scroll compressor 103, the gas-side three-way valve 116 and the liquid-side three-way valve 115 are closed.
The flow path of the refrigerant is shut off between the liquid-side three-way valve 115 via 07 and the pressure does not increase. Therefore, even when an abnormal pressure due to liquid sealing occurs, the pressure sensor 110 is not affected by the abnormal pressure.

As described above, according to the pressure sensor destruction prevention device of the embodiment of the present invention, if the gas side three-way valve 116 is not opened during the heating test operation in winter, the pressure sensor 110
Since no discharge pressure is applied to the
Is not affected by abnormally high pressure due to the closing of the gas side three-way valve 116 and the liquid side three-way valve 115. Even when the gas-side three-way valve 116 is open and the liquid-side three-way valve 115 is closed, an abnormally high pressure itself may be generated because the connection pipe to the indoor unit 107 and the indoor unit 107 serve as a buffer for the refrigerant gas. Since there is no pressure sensor 110, the pressure sensor 110 is not destroyed.

[0014]

As is apparent from the above embodiment, according to the present invention, when the gas side three-way valve is not opened during the heating test operation in winter, the low-pressure scroll compressor starts and the gas is discharged from the discharge pipe. The liquid sealing state is established between the side three-way valve and the pressure sensor can be reliably prevented from being broken due to abnormal pressure generation due to liquid compression.

[Brief description of the drawings]

FIG. 1 is a refrigeration cycle diagram of a pressure sensor destruction prevention device for an air conditioner according to one embodiment of the present invention.

FIG. 2 is a diagram of a conventional refrigeration cycle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gas side union 101 Outdoor unit 102 Inverter 103 Low pressure scroll compressor 104 Four way valve 110 Pressure sensor 111 Discharge pipe 112 Suction pipe 115 Liquid side three way valve 116 Gas side three way valve

Claims (1)

(57) [Claims] 1. An inverter for controlling an inverter in an outdoor unit, a low-pressure scroll compressor controlled by the inverter, a discharge pipe derived from the low-pressure scroll compressor, a suction pipe, and a refrigerant flow switching four-way. A valve,
An outdoor heat exchanger, a pressure sensor for pressure control, a liquid-side three-way valve, a gas-side three-way valve, and a gas-side union for connection to an indoor unit, and the pressure sensor is provided with the gas-side three-way valve and a gas-side union. And a pressure sensor destruction prevention device for an air conditioner, which is installed between the air conditioner and a heating test operation so that abnormal pressure is not applied to the pressure sensor.