JPS59586A - Air conditioner - Google Patents

Abstract

PURPOSE:To prevent the burning of bearings of a scroll compressor, by preventing the intermediate pressure from becoming higher than the discharge pressure and thereby securing the differential pressure required for feeding lubricating oil by providing a means for closing a suction passage for a prescribed time at the time of starting operation and defrosting operation in the suction passage of the compressor. CONSTITUTION:Defrosting of an outdoor heat exchanger 6 is performed by switching a four-way valve 2 by means of a controller 8 associated with a defrosting operation sensor 7 and circulating a coolant through a cycle shown by the solid line in the drawing. Simultaneously with the defrosting operation, a solenoid valve 30 is closed for a prescribed while by the instruction of the controller 8. After passing through the region where the suction pressure at the initial stage of the defrosting operation is raised and the intermediate pressure becomes higher than the discharge pressure, the solenoid valve 30 is opened by the instruction of the controller 8 for starting normal defrosting operation (this is also applied at the time of starting operation). Thus, since rising of the suction pressure can be prevented, it is eanbled to prevent the intermediate pressure from becoming higher than the discharge pressure, so that a sufficient differential pressure required for feeding lubricating oil can be obtained and bearings can be protected against damages.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of operating an air conditioner using a scroll compressor and an air conditioner.The cycle of a conventional air conditioner is as shown in FIG. Four-way valve 2
, indoor heat exchanger 3, check valve 4a, capillary tube 5
A, check valve 4b1, capillary cheap 5b, parallel circuit, outdoor heat exchanger 6, etc. are connected in series to form a cycle, and the sensor 11 controller 8 controls the heating operation by supplying the refrigerant in the direction shown by the broken line in the figure. The cooling operation and the defrosting operation form a cycle in which the refrigerant flows in the direction shown by the solid line. The compressor 1 is a scroll type compressor as shown in FIG. 2, and has a scroll compression mechanism 10 and a motor 12 housed in a closed container 11. And scroll compressor 10
combines an orbiting scroll 13 and a fixed scroll 14,
The crankshaft 16 is supported by a frame 15, and the orbiting scroll 13 and fixed scroll 14 are connected to a wrap 1 formed upright on plywood (mirror plates) 13a and 14a.
3b and 14b, which are combined with each other with their wraps facing inward. Also, the end plate 1 of the orbiting scroll. (An orbiting bearing +3C is provided on the back side of a, and the seven arm 15 and the fixed scroll 14 house the orbiting scroll 13 and are fastened together.The crank part 16b of the rank shaft 16 is inserted into the orbiting bearing 13C. On the other hand, the rotor 12a of the motor 12 is fixedly attached.
- A turning mechanism 13d is installed on the back side of the end plate +38 of the rule 13 and on the frame 15. Still, orbiting scroll 13
The back side of the arm plate 13a is connected to the airtight container 11 by the frame 15.
It is isolated from the inside. Crankshaft 16 has oil supply hole +6a
Oil is supplied to each bearing portion from this oil supply hole 16a. The fixed scroll 14 is provided with a suction hole 14C and a discharge hole 14d, and the suction hole 14G is provided with a suction hole 14C.
7 penetrates the closed container 11 and is fixed to the closed container 11. A discharge pipe 18 penetrates the closed container 11 and opens into the inside of the closed container 11.

In the scroll compressor, when the motor 12 rotates, the orbiting scroll 13 and the fixed scroll 14 are rotated relative to each other by the crank part +6b of the crankshaft 16 and the orbiter 1It13d, and the end plates 13a, 14a and the wrap 131),
As the space formed by 14b moves to the center, the volume of the space is reduced, compressing the refrigerant scum sucked in from the suction hole 14C, and discharging it from the discharge hole +4d. The discharged refrigerant gas passes through the airtight container 11 and is discharged from the discharge pipe 18 to the outside of the machine. A part of the discharged gas is used to cool the motor 12 inside the closed container 11.

The compression pressure of the refrigerant scum acts as a force that tends to separate the orbiting scroll 13 and the fixed scroll 14 from each other. For this reason, when the back surface of the end plate is equal to the suction pressure, the orbiting scroll 13 separates from the fixed scroll 14, reducing performance. Furthermore, if the back surface of the end plate is equal to the discharge pressure, the force pressing the orbiting scroll 13 against the fixed scroll 14 becomes excessive, increasing mechanical loss. For this reason, the end plate 13 of the orbiting scroll 13
The back pressure chamber 19 formed by the frame 15 and the back pressure chamber 19 communicates with the compression chamber through a pressure equalization hole provided in the end plate 13a of the orbiting scroll 13, and maintains its pressure at an intermediate pressure between the suction pressure and the discharge pressure. I have to. The crankshaft 16 supplies oil to the swing bearing 13C and the bearing provided on the upper part of the frame 15.
The centrifugal force due to the eccentricity of the oil supply hole 16a provided in
This is done by the differential pressure between the intermediate pressures within.

In the refrigeration cycle shown in FIG. 1, during heating operation, the refrigerant flows in the direction of the broken line, so liquid refrigerant accumulates in the indoor heat exchanger 3.
p. The entire outdoor heat exchanger 6 is cooled by the outside air. When the defrosting operation is started from this state, the discharged gas is rapidly liquefied as shown in FIG. 3, and the discharge pressure changes as shown by a curve 21. On the other hand, in the indoor heat exchanger 3, the accumulated refrigerant liquid evaporates and the incoming cold refrigerant gas is also rapidly heated, so the suction pressure changes as shown by curve 22, and the discharge pressure immediately after the start of defrosting. decreases and suction pressure increases. As a result, the pressure inside the compression chamber of the scroll compressor also rises, so that the intermediate pressure rises as shown by curve 23. This will partially create a state where the intermediate pressure is higher than the discharge pressure between points 24 and 25. As mentioned above, such a phenomenon results in the oil supply being obstructed by the differential pressure between the discharge pressure and the intermediate pressure, which causes the bearing to burn out. This also occurs when the start-up suction pressure and discharge pressure are balanced.

The present invention has been made in view of the above points, and it is an object of the present invention to provide an air conditioner that does not cause bearing burnout even during startup and defrosting operation.

In order to achieve the above object, the present invention provides means for temporarily stopping or reducing suction gas suction at startup and at the beginning of defrosting operation in the suction gas path of a scroll compressor, thereby reducing the suction pressure. This feature is configured to prevent the intermediate pressure in the back pressure chamber from rising higher than the discharge pressure.

Hereinafter, the present invention will be explained in detail using an embodiment yc shown in FIG.

In the figure, the same parts as in FIGS. 1 to 3 are represented by the same reference numerals, and the explanation thereof will be omitted.

Reference numeral 30 denotes a solenoid valve, which is installed in the suction gas path of the scroll compressor and is controlled to close temporarily at the time of startup or defrosting operation. The solenoid valve may be closed by another pressure control valve or the passage may be blocked. In the case of heating operation, the refrigerant scum compressed by the compressor 1 flows in the direction of the dashed arrow, flows into the indoor heat exchanger 3 through the four-way valve 2, and heats the air forcedly ventilated by the blower 26 to cool the room. heating. The liquefied refrigerant passes through the check valve 4a, is decompressed and expanded in the capillary cheep 5b, flows into the outdoor heat exchanger 6, absorbs heat from the outside air blown by the blower 27, and passes through the four-way valve 2 and the solenoid valve 30. It is sucked into the compressor 1. As the heating operation continues, the outdoor heat exchanger 6 will become clogged, making it necessary to defrost it. The defrosting operation is performed by switching the west valve 2 through the action of the controller 8 using the sensor 7, and defrosting the outdoor heat exchanger 6 by circulating the refrigerant in the cycle shown by the solid line. According to the instructions in step 8, operate the stain magnetic valve 30 with it closed for an appropriate time. After the suction pressure at the initial stage of derafting increases and the intermediate pressure reaches a region higher than the discharge pressure, the electromagnetic YP30 is opened according to instructions from the controller 8, sucking in suction gas and compressing it to resume normal defrosting operation. Move.

By doing this, the suction pressure is prevented from increasing, so that the intermediate pressure is not increased either, and the intermediate pressure is not higher than the discharge pressure, so that a sufficient differential pressure necessary for refueling can be ensured. Furthermore, even at the start of operation, the intermediate pressure may be higher than the discharge pressure; By operating the electromagnetic valve 30 with the electromagnetic valve 30 open for an appropriate time, it is possible to prevent the intermediate pressure from increasing at the start of operation. The above-mentioned control of the electromagnetic valve 30 may be performed by pressure detection or by a timer.

FIG. 5 shows another embodiment, in which a thin bypass passage 31 is provided in parallel with the solenoid valve 30, and the suction passage is throttled by closing the solenoid valve 30 during defrosting operation and at the start of operation. The amount of inhalation may be reduced.

The present invention has the above-described structure.7 This makes it possible to prevent bearing burnout.

[Brief explanation of the drawing]

Figure 1 is a conventional refrigeration cycle system diagram, Figure 2 is a cross-sectional view of a scroll compressor, and Figure 3 is a pressure diagram. Inside the Shimizu Plant of the Works 0 Inventor Tetsuya Arata 390 Muramatsu, Shimizu City Inside the Mechanical Research Laboratory of Hitachi, Ltd.

Claims (1)

[Claims] 1. The airtight container has a high pressure, and has an intermediate pressure chamber with a pressure between the suction pressure and the discharge pressure, and the bearing is lubricated by the pressure difference between the intermediate pressure and the discharge pressure. An air conditioner using a scroll compressor, characterized in that the suction passage of the scroll compressor is also provided with means for closing or narrowing the suction passage for an appropriate time at the start of defrosting operation and at the start of operation. Air conditioner. 2. The air conditioner according to claim 1, wherein the means for closing the suction passage is a solenoid valve. 3. The air conditioner according to claim 1, wherein the narrowing means includes a narrow bypass passage C.