JPH05322355A - Air conditioner - Google Patents

Abstract

PURPOSE:To switch a valve body of a four-way switching valve to a normal state and to prevent its switching defect by delaying a predetermined time from the time of starting a compressor to open a switching valve provided in a bypass circuit, and closing it after a predetermined time is elapsed. CONSTITUTION:A bypass circuit to be connected to an inlet of an accumulator from a discharge side tube of a compressor through a switching valve is provided. The valve is opened after a predetermined time from the start of the compressor, and closed after a predetermined time is elapsed. The valve is so constructed as to be opened after the predetermined time from the start of the compressor, a pressure difference thereby reaches an operating pressure of the valve, and a valve body of the valve is switched to a normal state to prevent its switching defect. For example, when an operation switch 11 is closed in an electric circuit diagram of an air conditioner, an electromagnetic switch 12 for a compressor is excited, and a timer coil 13 is simultaneously excited. Since a contact 14a is a time limiting operating and time limiting resetting contact, a coil 15 for the valve is excited when the valve is closed after 10 sec from when the coil 13 is energized, and the valve is opened. After three min, the contact 14a is opened, the coil 15 is not energized, and the valve is not closed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration cycle for a heat pump type air conditioner.

[0002]

2. Description of the Related Art In FIG. 3, 1 is a compressor, 2 is a four-way switching valve for switching a refrigerant circuit, 3 is an outdoor heat exchanger, 4, 5
Is a first and second expansion device functioning as an expansion mechanism during heating operation and cooling operation, respectively, 6 is an indoor heat exchanger, 7 is an accumulator, and these are sequentially connected by refrigerant pipes to form a refrigeration cycle circuit. Is configured. Reference numeral 10 is a bypass circuit connected from the compressor discharge side pipe to the accumulator inlet side, and 10a is an opening / closing valve provided in the middle of the bypass circuit. In addition, 9 is an outdoor air blower that blows air to the outdoor heat exchanger 3, and 4a and 4b are a first pressure reducing device (for example, a capillary tube) that constitutes the first expansion device 4 and a circuit that bypasses this. First provided
The check valves 5a and 5b are second check valves provided in a second pressure reducing device (for example, a capillary tube) that constitutes the second expansion device 5 and a circuit that bypasses the second pressure reducing device. A blower 8 blows air to the indoor heat exchanger 6 of the refrigeration cycle circuit.

The operation of the air conditioner having such a configuration will be described below. During the cooling operation (the flow of the refrigerant is indicated by a solid line arrow in the figure), the high-temperature high-pressure gas refrigerant discharged from the compressor 1 passes through the four-way switching valve 2 and the outdoor heat exchanger 3 blows the outdoor air. The gas refrigerant is condensed and liquefied by exchanging heat with the outdoor air blown by 9. And
First check valve 4b in the bypass circuit of the first expansion device 4
The second decompression device 5 that constitutes the second expansion device 5
It is introduced into the a side and reduced in pressure to become a low temperature low pressure liquid refrigerant.
After that, the liquid refrigerant enters the indoor heat exchanger 6, exchanges heat with the indoor air blown by the indoor blower 8, cools the indoor air, and the liquid refrigerant is vaporized and gasified by the four-way switching valve 2 A refrigerating cycle for cooling is constituted by returning to the compressor 1 through the accumulator 7, and thereafter the refrigerant is circulated in the refrigerating cycle path described above while repeating liquefaction and vaporization.

On the other hand, during the heating operation (the flow of the refrigerant is shown by the dashed arrow in the figure), the high-temperature high-pressure gas refrigerant discharged from the compressor 1 is switched to the heating side by the four-way switching valve 2.
And enters the indoor heat exchanger 6 to exchange heat with the indoor air blown by the indoor blower 9 to heat the indoor air, whereby the gas refrigerant is condensed and liquefied. Then, this liquid refrigerant passes through the second check valve 5b in the circuit that bypasses the second expansion device 5, is guided to the first pressure reducing device 4a that constitutes the first expansion device 4, and is decompressed. , Becomes a low-temperature low-pressure liquid refrigerant. After that, the liquid refrigerant enters the outdoor heat exchanger 3, exchanges heat with the outdoor air blown by the outdoor blower 9, collects heat from the outdoor air to cool the outdoor air, and thereby the liquid refrigerant is vaporized and gasified, It returns to the compressor 1 through the four-way switching valve 2 and the accumulator 7, which constitutes a refrigeration cycle during heating.

When the operation of the compressor 1 is stopped, the refrigerant gradually dissolves in the refrigerating machine oil. When the compressor 1 is started in this state, the pressure in the crankcase suddenly drops and the refrigerant dissolved in the oil evaporates, causing an oil forming phenomenon in the oil and causing poor lubrication. It was. Therefore, a bypass circuit 10 having a pipe having an inner diameter smaller than the inner diameter of the discharge-side pipe connected to the inlet of the accumulator 7 from the discharge-side pipe of the compressor 1 via the on-off valve 10a is provided, and the on-off valve 1 is operated for 3 minutes from the time of startup.
Opening 0a prevented a low pressure drop.

This will be explained with reference to an electric circuit diagram shown in FIG.
When the operation switch 11 is turned on, the compressor electromagnetic switch 12 is excited and the timer coil 13 is excited at the same time, and the contact 14b is closed, so that the on-off valve coil 15 is excited and the on-off valve is opened. .. Since the contact 14b is a momentary operation time-delayed return contact, it is closed at the same time when the timer coil is excited, and is opened 3 minutes later.

[0007]

The four-way switching valve is for switching the flow of the refrigerant by utilizing the pressure difference. In the conventional air conditioner as described above, the bypass is performed at the same time when the compressor is started during the heating operation. Since the on-off valve 10a of the circuit 10 is opened, the pressure difference applied to the four-way switching valve becomes small, so that the operating pressure of the four-way switching valve cannot be reached, and the valve element stops at the intermediate position to cause switching failure.

The present invention has been made to solve the above problems, and eliminates switching failure of the four-way switching valve 2 at the time of starting the compressor during heating operation, and lowers the low-pressure pressure when starting oil. The purpose is to prevent the forming phenomenon, to protect the quality of the compressor, and to maintain the reliability of the product itself.

[0009]

In the air conditioner according to the present invention, an opening / closing valve provided in a bypass circuit is opened after a predetermined time from the time of starting the compressor, and is closed after a required time has elapsed.

[0010]

According to the present invention, since the opening / closing valve is opened after a predetermined time has elapsed from the start of the compressor, the pressure difference reaches the four-way switching valve operating pressure, and the valve body of the four-way switching valve is normally switched and switched. Defects are prevented.

[0011]

【Example】

Example 1. FIG. 1 is an electric circuit diagram of an air conditioner showing an embodiment of the present invention. In FIG. 1, the operation switch 11
When turned on, the electromagnetic switch 12 for the compressor is excited and at the same time the timer coil 13 is excited. Since the contact 14a is a timed operation timed return contact, it closes 10 seconds after the timer coil 13 is excited and the on-off valve coil 15 is closed.
Is excited and the on-off valve is opened. And 3 minutes later, contact 1
4a is opened, the on-off valve coil 15 is de-energized, and the on-off valve is closed.

FIG. 2 is a diagram showing the relationship between the pressure difference in height and the elapsed time in the air conditioner. In FIG. 2, the vertical axis represents the difference in pressure and the horizontal axis represents the elapsed time. According to this diagram, the height differential pressure increases with time, reaches at time t ₁ to the lowest four-way switching valve operating pressure p _1, time t ₂ (= 10 seconds) the pressure difference in the p _2, and the minimum Four-way switching valve operating pressure p
You can see that it exceeds ₁ .

Embodiment 2. Although the bypass circuit 10 connected from the compressor discharge side pipe to the accumulator inlet is shown in the first embodiment, the same effect can be obtained by using the bypass circuit communicating from the compressor discharge side pipe to the accumulator 7 main body. be able to.

[0014]

As described above, in the air conditioner according to the present invention, since the opening / closing valve that opens after a predetermined time from the start of the compressor and closes after the required time is provided in the middle of the bypass circuit, the pressure difference is four-way. When the switching valve operating pressure is reached, the valve body of the four-way switching valve switches normally and switching failure is prevented, and the oil forming phenomenon due to the drop in low pressure at startup is prevented to protect the quality of the compressor and the product body. It has the effect of maintaining reliability.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram of an air conditioner according to an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a high / low pressure difference and an elapsed time in an air conditioner according to an embodiment of the present invention.

FIG. 3 is a refrigerant circuit diagram of a conventional air conditioner.

FIG. 4 is an electric circuit diagram of a conventional air conditioner.

[Explanation of symbols]

 1 Compressor 2 Four-way switching valve 3 Outdoor heat exchanger 4 First expansion device 5 Second expansion device 6 Indoor heat exchanger 7 Accumulator 8 Indoor blower 10 Open / close valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kozo Mukai 6-5-66, Teira, Wakayama City Mitsubishi Electric Engineering Co., Ltd. Itami Works Wakayama Branch (72) Inventor Koji Itakura 6-Tepal, Wakayama 5th 66th Mitsubishi Electric Engineering Co., Ltd. Itami Works Wakayama Branch

Claims (1)

[Claims] 1. A compressor, a four-way switching valve, an outdoor heat exchanger, a first expansion device, a second expansion device, an indoor heat exchanger, and an accumulator are sequentially connected by a refrigerant pipe. A refrigerating cycle circuit comprising, and a blower for blowing air to the indoor heat exchanger, wherein a bypass circuit connected from the discharge side pipe of the compressor to the accumulator inlet via an opening / closing valve is provided, and An air conditioner characterized in that an on-off valve is opened after a lapse of a predetermined time from the start of a compressor and closed after a required time has elapsed.