JPH06221695A - Compression device - Google Patents

Abstract

PURPOSE:To prevent each of compressors from being damaged due to a lack of lubrication by a method wherein when all of or a part of a plurality of compressors is operated, lowering of a the level of lubricant oil within the housing of each of the compressors is prevented. CONSTITUTION:An oil reserve tank 31 is concentrically arranged with an accumulator 30. A plurality of low pressure housing closed type compressors 11 to 15 having the same specification are arranged concentrically around the oil reserve tank 31. Outlet pipes 30a to 30e of the accumulator 30 and housings of a plurality of compressors 11 to 15 are connected through respective suction pipes 38 to 42 having the same size and same shape to each other. The oil reserve tank 31 and the housings of a plurality of compressors 11 to 15 are connected to each other through respective uniform oil pipes 43 to 47 having the same size and same shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compression unit suitable for air conditioners and the like.

[0002]

2. Description of the Related Art A system diagram of a conventional air conditioner is shown in FIG. O is an outdoor unit, which includes a compression unit 10, a four-way switching valve 1, an outdoor heat exchanger 2, a heating expansion valve 3, a check valve 4, and the like. A, B and C are indoor units, which are indoor heat exchangers A1, B1 and C1, expansion valves A2, B2 and C3 for cooling, and check valves A3 and B, respectively.
Equipped with 3, C3, etc.

The compression unit 10 is, as shown in FIG. 4, a low pressure housing type hermetic compressor 1 having a plurality of identical specifications.
1, 12, 13, 14, 15, check valve 16, 17, 18, 19, 20, oil separator 21, accumulator 22, oil return pipe 23, throttle 24
And so on.

During the full capacity cooling operation of this air conditioner, the gas refrigerant discharged from each of the compressors 11, 12, 13, 14, 15 of the compression unit 10 has check valves 16, 17, 18, 19, 20. After merging through, the oil enters the oil separator 21, where the mist of the lubricating oil contained in the gas refrigerant is separated. The oil separated by the oil separator 21 enters the suction side pipe 8 through the oil return pipe 23 and the throttle 24 provided therein, and enters the accumulator 22 along with the gas refrigerant passing therethrough.

The gas refrigerant flowing out from the oil separator 21 enters the outdoor heat exchanger 2 via the discharge side pipe 7 and the four-way switching valve 1 as shown by the solid line arrow in FIG. Condensate and liquefy. The liquid refrigerant flows through the check valve 4 into the indoor units A, B, C in parallel and is adiabatically expanded by being throttled in the process of passing through the cooling expansion valves A2, B2, C2, and then indoors. It enters the heat exchangers A1, B1, C1 where it cools the room air and evaporates and evaporates. This gas refrigerant branches after passing through the four-way switching valve 1, the suction side pipe 8, and the accumulator 22, and then passes through the suction pipes 25, 26, 27, 28, 29, and the housing of each compressor 11, 12, 13, 14, 15. Are inhaled in parallel.

During full capacity heating operation, the four-way switching valve 1
, The gas refrigerant discharged from the compression unit 10 is supplied to the discharge side pipe 7, the four-way switching valve 1, and the indoor heat exchangers of the indoor units A, B, and C as indicated by the broken line arrow. A1, B1, C1, check valves A3, B3, C3, expansion valve 3 for heating,
The outdoor heat exchanger 2, the four-way switching valve 1, and the suction side pipe 8 are passed in this order and returned to the compression unit 10.

During cooling operation, each cooling expansion valve A2, B2, C2
The opening degree of the refrigerant is adjusted, and the opening degree of the heating expansion valve 3 is adjusted during the heating operation, so that the superheat degree of the refrigerant sucked into each of the compressors 11 to 15 is maintained constant. And each indoor unit A,
The capacities and operating numbers of the plurality of compressors 11 to 15 are increased or decreased according to the required capacities of B and C.

[0008]

In the above conventional compression unit, for example, when the compressor 11 and the compressor 12 are operated and the compressors 13, 14, 15 are stopped, the suction pipes of the compressors 11, 12 are Since the sizes and shapes of 25 and 26 are different from each other, a difference in pressure loss occurs when the gas refrigerant passes through them, and the pressures inside the housings of the compressors 11 and 12 are different from each other. As a result, the gas refrigerant has a lower pressure in the compressor, for example, a large amount is sucked into the housing of 11, so that less lubricating oil is returned to the housing of the other compressor 12 along with the gas refrigerant, There is a risk that the oil level of the lubricating oil stored in the housing will gradually decrease, resulting in poor lubrication and an accident such as seizure. On the other hand, since the suction pressure does not build up in the stopped compressors 13, 14, and 15, the lubricating oil is
Since it does not return to 3, 14, 15 and is sucked by the operating compressors 11, 12, the oil level of the stopped compressors 13, 14, 15 gradually decreases, and a seizure accident may occur when restarting the operation. There was a risk of causing it.

[0009]

The present invention has been invented to solve the above-mentioned problems, and its gist is to provide a concentric circle centered on an oil reserve tank arranged concentrically with an accumulator. A plurality of low-pressure housing type hermetic compressors having the same specifications are arranged on the upper side, and the plurality of outlet pipes of the accumulator and the housings of the plurality of compressors are provided through different suction pipes of the same size and shape. The compression unit is characterized in that the oil reserve tank and the housings of the plurality of compressors are connected to each other through separate oil equalizing pipes having the same size and shape.

[0010]

In the present invention, because of the above structure, the gas is sucked from the plurality of outlet pipes of the accumulator through the different suction pipes into the housing of the operating compressor, and the operating compressor is operated. The pressures in the housings are equal to each other and lower than the pressure in the housing of the compressor at standstill. Thus, the lubricating oil stored in the oil reserve tank does not flow into the housing of the compressor that is stopped, but flows into the housing of the compressor that is operating through separate oil equalizing pipes.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENT One embodiment of the present invention is shown in FIG. An oil reserve tank 31 is arranged concentrically below the accumulator 30, and a plurality of (5 in the figure) low-voltage housing type of the same specifications are arranged at equal intervals on a concentric circle centered on the oil reserve tank 31. Hermetic compressor 11, 12, 13, 1
4, 15 are arranged.

The accumulator 30 has a plurality of outlet pipes 30a to 30e as many as the compressors, and the outlet pipes 30a to 30e and the housings of the plurality of compressors 11 to 15 have the same dimensions and
They are connected via suction pipes 38, 39, 40, 41, 42 extending in the radial direction of the shape. Further, the oil reserve tank 31 and the housings of the plurality of compressors 11 to 15 are connected to each other through oil equalizing pipes 43, 44, 45, 46, 47 having the same size and shape and extending in the radial direction.

The discharge pipes 48, 49, 50, 51 of the compressors 11 to 15,
Check valves 16, 17, 18, 19, 20 are provided at 52, respectively, and oil separators 53, 54, 55, 56, 57 are provided on the upstream side thereof. The oil separated by these oil separators 53-57 passes through oil return pipes 58, 59, 60, 61, 62 and capillary tubes 63, 64, 65, 66, 67 interposed therebetween and each compressor 11-.
It is designed to return to 15 suction pipes 38 to 42. Then, the oil separated by the oil separator 21 is returned to the oil reserve tank 31 via the oil return pipe 23 and the capillary tube 24 interposed therein. Other configurations are similar to those of the conventional one shown in FIGS. 3 and 4, and corresponding members are designated by the same reference numerals.

However, when all the compressors 11 to 15 are operated at the same time, the gas refrigerant discharged from each of the compressors 11 to 15 enters the oil separators 53 to 57 through the discharge pipes 48 to 52 thereof, where The mist of lubricating oil contained in the gas refrigerant is separated. The separated oil returns into the housings of the compressors 11-15 via the oil return pipes 58-62, the capillary tubes 63-67 interposed therein and the suction pipes 38-42.

The gas refrigerant flowing out from each of the oil separators 53 to 57 merges through the check valves 16 to 20 and then enters the oil separator 21, where the lubricating oil remaining in the gas refrigerant is further separated. The separated oil enters the oil reserve tank 31 via the oil return pipe 23 and the capillary tube 24 interposed therein, and is temporarily stored therein, and then passes through the oil equalizing pipes 43 to 47 and each compressor 11. Return to the housing of ~ 15.

The gas refrigerant flowing out of the oil separator 21 circulates in the system of the air conditioner through the discharge side pipe 7 and then enters the accumulator 30 through the suction side pipe 8 and is contained in the gas refrigerant here. After separating the mist of liquid refrigerant or lubricating oil, it returns to the inside of the housing of each compressor 11-15 through its outlet pipes 30a-30e and suction pipes 38-42.

Since the compressors 11 to 15 are composed of low pressure housing type hermetic compressors having the same specifications, during simultaneous operation of these,
The suction pressure and the discharge pressure of the compressors 11 to 15 are equal, and these housings have suction pipes 38 of the same size and shape.
Since they are connected to the outlet pipes 30a to 30e of the accumulator 30 via ~ 42, the pressure loss when the refrigerant gas passes through the suction pipes 38 to 42 becomes equal, and therefore, in the housing of each compressor 11 to 15. The pressure is the same. As a result, each compressor 11 ~
The amount of the refrigerant gas sucked into the housing of 15 and the amount of the lubricating oil accompanied with the refrigerant gas become equal, and the lubricating oil in the oil reserve tank 31 has the same size and shape as the equalizing pipes 30a to 30e.
Since it flows into the housing of each of the compressors 11 to 15 through the above, the oil level of the lubricating oil stored therein becomes substantially uniform.

A part of the compressors 11 to 15, for example, the compressor 11 and
When 12 is operated and the other compressors 13, 14, 15 are stopped, the pressure in the housing of the stopped compressors 13, 14, 15 is maintained at the same pressure as in accumulator 30. Therefore, the lubricating oil stored in the oil reserve tank 31 is not sucked into these housings.

On the other hand, the pressure inside the housings of the compressors 11 and 12 during operation becomes lower than the pressure inside the accumulator 30 by the amount of pressure loss when the refrigerant gas passes through the suction pipes 38 and 39, but the suction pipes 38 and 39. Since they have the same size and shape, their pressure losses are equal and therefore the pressures in the housings of compressors 11 and 12 are equal. Therefore, the lubricating oil stored in the oil reserve tank 31 passes through the oil equalizing pipes 43 and 44 and the compressor 1
It flows into the housings 1 and 12 and the oil level in it becomes almost uniform. The same applies when the number of operating vehicles is 1, 3, or 4.

In the above embodiment, five compressors are provided, but when four compressors are provided, as shown in FIG. 2 (A), and when three compressors are provided. Figure 2
They can be placed on concentric circles at equal intervals as shown in (B), or can be placed on one side at different intervals on concentric circles as shown in FIGS. 2 (C) and 2 (D). If so, the installation space can be saved.

[0021]

According to the present invention, a plurality of low pressure housing type hermetic compressors having the same specifications are arranged on a concentric circle centered on an oil reserve tank arranged concentrically with the accumulator, and a plurality of accumulators are provided. The outlet pipe of the compressor and the housings of the plurality of compressors through separate suction pipes of the same size and shape, and the oil reserve tank and the housings of the compressors of the same size and shape. Since they are connected via the oil equalizing pipe, the pressures inside the housing of the compressor during operation are equal to each other, and are lower than the pressure inside the housing of the compressor during stop. Thus,
The lubricating oil stored in the oil reserve tank does not flow into the housing of the compressor that is stopped, but flows into the housing of the compressor that is operating, and the oil levels therein become equal to each other. As a result, it is possible to prevent a decrease in the oil level in the housing of the compressor even when all of the plurality of compressors are operated, as well as when a part thereof is operated. Accidents such as seizure can be prevented and the reliability of the compression unit can be improved.

[Brief description of drawings]

1 shows an embodiment of the present invention, (A) is a system diagram, (B)
Is a top view.

FIG. 2 is a top view of another embodiment of the present invention, in which (A), (B),
(C) and (D) show different arrangements.

FIG. 3 is a system diagram of a conventional air conditioner.

FIG. 4 is a system diagram of a conventional compression unit.

[Explanation of symbols]

 30 Accumulator 30a, 30b, 30c, 30d, 30e Outlet pipe 31 Oil reserve tank 11, 12, 13, 14, 15 Compressor 38, 39, 40, 41, 42 Suction pipe 43, 44, 45, 46, 47 Oil equalizing pipe

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiko Sasakura 1-chome, Asahimachi, Nishibiwajima-cho, Nishikasugai-gun, Aichi Mitsubishi Heavy Industries, Ltd.

Claims (1)

[Claims] 1. A plurality of low pressure housing type hermetic compressors having the same specifications are arranged on a concentric circle centered on an oil reserve tank arranged concentrically with the accumulator, and a plurality of outlet pipes of the accumulator and the above The housings of a plurality of compressors are connected through different suction pipes of the same size and shape, and the oil reserve tank and the housings of the plurality of compressors are connected through respective equalizing pipes of the same size and shape. A compression unit characterized by being connected together.