JP2002130871A - Accumulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an accumulator 5 improved in reliability by making an oil returning port 11c clogged hardly. SOLUTION: The opening area of a refrigerant inflow port 11a of refrigerant outflow members 11, 12 is made larger than the passage area of a refrigerant outflow pipe 11b, while the oil returning port 11c is opened on the refrigerant outflow members 11, 12 to take oil in pressure resistant vessels 7, 8, 9 into the refrigerant outflow members 11, 12. According to this method, a pressure loss due to a contracted flow upon flowing of gas refrigerant in the accumulator 5 into the refrigerant inflow port 11a or another pressure loss due to the friction of a pipe upon the flowing of gas refrigerant through the inside of a refrigerant outflow pipeline 11 is lightened, and a pressure difference between the inside of the accumulator 5 and the inside of the refrigerant outflow pipeline 11 is reduced whereby the optimum returning amount of oil can be obtained, even when the diameter of the oil returning port 11c is increased and the clogging of the oil returning port 11c can be made difficult.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an accumulator for a vapor compression refrigeration cycle, and more particularly to a structure of an accumulator suitable for use in a refrigeration cycle having a high refrigerant pressure, such as a supercritical vapor compression type.

[0002]

2. Description of the Related Art In a vapor compression refrigeration cycle comprising a compressor, a radiator, a decompression means, an evaporator, etc., a CFC-based refrigerant which has been conventionally used is not used due to ozone destruction and global warming. There are requests for bans and reductions.

[0003] Therefore, as an alternative refrigerant to these CFC-based refrigerants, the ozone layer is not destroyed and the greenhouse effect (GW)
A refrigerating cycle using carbon dioxide having P) of 1 as a refrigerant is disclosed in Japanese Patent Publication No. Hei 7-18602.

[0004] In a refrigeration cycle using a chlorofluorocarbon-based refrigerant, the condensing pressure of the refrigerant is used below a critical point.
In a cycle using carbon dioxide as a refrigerant, a supercritical vapor compression refrigeration cycle in which the high pressure side is in a supercritical region is provided.

FIG. 5 is a structural view of a conventional accumulator used for a refrigeration cycle of a CFC-based refrigerant. In order to reduce the pressure loss on the suction side due to the low pressure on the low pressure side, the pipe diameter was set to be as large as about 13 mm. It becomes a thin thing.

The oil return hole for returning oil to the compressor, which is opened in the refrigerant outflow pipe inside the accumulator, has a diameter of about 1 mm in the refrigeration cycle of the CFC-based refrigerant. In the cycle, since the pressure difference between the inside of the accumulator and the inside of the refrigerant outflow pipe also increases, a fine hole having a diameter of about 0.4 mm is formed in order to make the oil return amount appropriate.

[0007]

However, in such a fine oil return hole as described above, the hole is easily clogged with sludge such as abrasion powder of the compressor, and the oil runs out and the compressor is seized. There is a problem.

[0008] The present invention has been made in view of the above problems, and has as its object to provide an accumulator in which the oil return hole is hardly clogged and reliability is improved.

[0009]

In order to achieve the above object, the following technical means are employed.

According to the first aspect of the present invention, the opening area of the refrigerant inflow port (11a) of the refrigerant outflow members (11, 12) is
In addition to making the passage area of the refrigerant outflow pipe (11b) larger, an oil return hole (11) is formed in the refrigerant outflow members (11, 12).
c) is opened, and the oil in the pressure-resistant containers (7, 8, 9) is taken into the refrigerant outflow members (11, 12).

As a result, the pressure loss due to the contraction of the gas refrigerant inside the accumulator when flowing into the refrigerant inflow port is reduced, and the pressure difference between the inside of the accumulator and the inside of the refrigerant outflow pipe is reduced. Even if is increased, an appropriate amount of oil can be returned, so that the diameter of the oil return hole can be increased to make it difficult to clog.

According to the second aspect of the present invention, the refrigerant inlet (1)
The opening area of 1a) is expanded to expand the refrigerant outflow pipe (11).
It is characterized in that it is larger than the passage area of b).

[0013] The above effect can be obtained by expanding the portion of the refrigerant outflow pipe at the refrigerant inflow port without using new parts.

According to the third aspect of the present invention, the refrigerant outflow member (11, 12) is provided in the pressure-resistant container (7, 8, 9), and has a cylindrical part (12) having an opening at an upper side; A refrigerant outflow pipe (11) extending from the outflow pipe (11b) into the tubular part (12), and having an opening formed in the refrigerant inflow port (11a).
The opening area of the refrigerant inlet (11a) is larger than the passage area of the refrigerant outlet pipe (11b).

[0015] By combining a cylindrical part having a large diameter with a pipe serving as a refrigerant outflow pipe, a refrigerant outflow path having a large opening area of the refrigerant inflow port can be formed.

According to the fourth aspect of the present invention, in the refrigerant outflow pipe (11), from the vicinity of the oil return hole (11c) provided near the bottom of the pressure-resistant container (7, 8, 9) to the refrigerant inflow port (11a). The cross-sectional area of the portion is
It is characterized in that it is larger than the passage area of b).

As a result, pressure loss due to pipe friction when the gas refrigerant flows through the refrigerant outflow pipe is reduced, and the differential pressure between the accumulator and the refrigerant outflow pipe is reduced, so that the diameter of the oil return hole is increased. Even so, an appropriate amount of oil can be returned, so that the diameter of the oil return hole can be increased to make it difficult to clog.

Incidentally, the reference numerals in parentheses of the above means are examples showing the correspondence with specific means described in the embodiments described later.

[0019]

Next, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment) A first embodiment will be described with reference to FIGS. 1 and 2. FIG. FIG. 1A is a structural view of an accumulator 5 according to the first embodiment of the present invention.
(B) is a graph showing a pressure change in each corresponding part. FIG. 2 is a schematic diagram of a vapor compression refrigeration cycle.

A compressor 1 receives a driving force from an external drive source such as an engine or a motor and adiabatically compresses a low-temperature and low-pressure gas refrigerant into a high-temperature and high-pressure gas refrigerant. Radiator for exchanging heat with the fluid such as water flowing through the heat exchanger of 2a for cooling the gas refrigerant of 2a.
The expansion valve as a pressure reducing means for adiabatically expanding the high-pressure refrigerant from the compressor into a gas-liquid two-phase refrigerant, and the heat exchange between the gas-liquid two-phase refrigerant depressurized by the expansion valve 3 and the conditioned air is performed. The evaporator 5 evaporates the refrigerant and cools the conditioned air. The gas-liquid two-phase refrigerant exiting the evaporator 4 is introduced into the evaporator 5, and the gas-liquid two-phase refrigerant is separated into gas and liquid by a difference in specific gravity. An accumulator in which the stored liquid refrigerant is stored.

The accumulator 5 has a cylindrical body 8 made of a steel plate.
On both sides, the hemispherical end plates 7 and 9 are also welded by a steel plate to form a pressure-resistant container. At the center of the end plate 7, a copper refrigerant inflow pipe 6 for connection with the outlet of the evaporator 4 by a pipe is brazed, and the gas-liquid two-phase refrigerant from the evaporator 4 is introduced into the accumulator 5 therefrom. I do.

On the inner side of the joint surface between the head plate 7 and the body 8,
A separation plate 10 having a plurality of holes formed near the outer periphery is fixed, and gas-liquid two-phase refrigerant flowing from the refrigerant inflow pipe 6 collides with the separation plate 10 to separate gas and liquid.

At the center of the accumulator 5 below the separation plate 10, a refrigerant outlet pipe 11 made of copper is installed as a refrigerant outlet member for guiding gas-liquid separated gas refrigerant to the compressor 1. It is a refrigerant inlet 11a.

An oil return hole 11c is opened in the lower portion of the refrigerant outflow pipe 11 near the bottom of the pressure-resistant container, and the oil in the liquid refrigerant accumulated in the accumulator 5 is sucked from this hole together with the liquid refrigerant. And returned to the compressor 1.

The refrigerant outlet pipe 11 is brazed through the center of the end plate 9, and a part coming out of the pressure vessel is connected to an inlet of the compressor 1 by a refrigerant outlet pipe 11 b.
It has become.

Next, the operation of the above configuration will be described.

The gas-liquid two-phase low-pressure refrigerant having passed through the evaporator 5 flows into the accumulator 5 through the refrigerant inflow pipe 6. The inflowing low-pressure refrigerant collides with the separation plate 10 and the flow velocity is reduced, and the liquid refrigerant having a large specific gravity accumulates below the pressure-resistant container.
3 is formed.

The gas refrigerant above the gas-liquid separated accumulator 5 is sucked from the refrigerant inlet 11a of the refrigerant outlet pipe 11 by the suction action of the compressor 1.

At this time, the oil mixed in the liquid refrigerant stored in the lower part of the accumulator 5 is sucked through an oil return hole 11c provided in the lower part of the refrigerant inflow pipe 11 and returned to the compressor 1.

The present invention is characterized in that, in the refrigerant outlet pipe 11, the opening area of the refrigerant inlet 11a and the refrigerant inlet 11a
The cross-sectional area of the portion from a to the vicinity of the oil return hole 11c is
The expanded pipe is made larger than the passage area of the refrigerant outflow pipe 11b.

As a result, the pressure loss due to the contraction of the gas refrigerant inside the accumulator 5 when flowing into the refrigerant inlet 11a and the pressure loss due to pipe friction when the gas refrigerant flows through the refrigerant outlet pipe 11 are reduced. Accumulator 5
Since the pressure difference between the inside and the inside of the refrigerant outflow pipe 11 is reduced, an appropriate amount of oil can be returned even if the diameter of the oil return hole 11c is increased. Can be.

Referring to FIG. 1 (b), which is a graph showing pressure changes at various parts in the accumulator 5, the refrigerant flowing from the refrigerant inflow pipe 6 at the pressure of a indicates that the refrigerant enters the pressure-resistant container. Pressure drop due to an increase in the flow area
Pressure.

Next, in the case of the conventional narrow refrigerant outflow pipe 11 (shown by a broken line), when the refrigerant flows into the narrow refrigerant inflow port 11a, a pressure loss called a contraction occurs and the pressure becomes the pressure indicated by the broken line c. Thereafter, by flowing through the thin refrigerant outflow pipe 11, a pressure loss called pipe friction is generated, and the refrigerant flows out of the accumulator 5 while the pressure gradually decreases.

The oil return hole 11c has a pressure b in the accumulator 5 and an oil return hole 1 in the refrigerant outlet pipe 11.
There was a pressure difference from the pressure c1 at the position 1c.

However, in the present invention, first, the refrigerant inlet 11a
Has a large opening area, the pressure loss of contraction when the refrigerant flows in is reduced, and the pressure becomes the pressure indicated by the solid line d. afterwards,
Also when flowing through the refrigerant outflow pipe 11, since the pipe is expanded, the pressure loss of pipe friction is reduced, and the pressure reaches the refrigerant outflow pipe 11b without decreasing much. Here, a pressure loss called a contraction occurs, and the pressure finally reaches the pressure indicated by the solid line e and leaves the accumulator 5.

However, in the oil return hole 11c, the pressure b in the accumulator 5 and the pressure d in the refrigerant outflow pipe 11
Will be reduced.

(Second Embodiment) FIG. 3 is a structural view of an accumulator 5 according to a second embodiment of the present invention.

In the first embodiment, the type in which the refrigerant flows in from the upper side and flows out downwards is a type in which the refrigerant flows in from the upper side and flows out upwards. When the accumulator 5 is mounted on a vehicle body, the inflow-side pipe and the outflow-side pipe can be connected from above, so that the workability is good.

The point of the internal structure different from that of the first embodiment is that a cylindrical part 12 having an opening on the upper side is arranged in the center of the accumulator 5 below the separating plate 10. Then, a refrigerant outflow pipe 11 made of copper is erected therein and penetrated through the center of the separation plate 10 and brazed through the center of the end plate 7. It is a refrigerant outflow pipe 11b for connecting to the inlet by piping. The oil return hole 11c is provided in a lower portion of the tubular part 12 near the bottom of the pressure-resistant container.

As described above, the refrigerant outflow member may be divided into two parts, ie, the cylindrical part 12 having a large diameter and the refrigerant outflow pipe 11.
A refrigerant outflow path in which an upper opening portion of the refrigerant outlet 11a is formed as a refrigerant outlet 11a. Can be larger than the passage area.

As a result, the pressure loss due to the contraction of the gas refrigerant inside the accumulator 5 when flowing into the refrigerant inlet 11a and the pressure loss due to pipe friction when the gas refrigerant flows inside the cylindrical part 12 are reduced. , Accumulator 5
Since the pressure difference between the inside and the inside of the cylindrical part 12 is reduced, an appropriate amount of oil can be returned even if the diameter of the oil return hole 11c is increased. Can be.

The tubular part 12 may be joined to the center of the end plate 9 or may be held below the refrigerant outflow pipe 11 so as to secure a refrigerant outflow path. Also, this cylindrical part 1
2 can be made of a thin-walled tube material or a nylon-based resin tube because the pressure resistance condition is not severe.

(Other Embodiments) FIG. 4 is a structural view of an accumulator 5 according to another embodiment of the present invention.

FIG. 4A shows the same type as FIG. 3 in which the refrigerant flows in from above and flows out. As in the accumulator 5 used in the conventional refrigeration cycle of the CFC-based refrigerant, the refrigerant outflow pipe 11 has a U-outlet. The end area of the one end of the accumulator 6 that opens as the refrigerant inlet 11a is expanded to increase the opening area.

FIGS. 4 (b) and 4 (c) show the cylindrical part 12 joined to the center of the end plate 9 as a simple tube having only the oil return hole 11c, and FIG. 4 (b) shows the refrigerant outlet pipe. 11
b is taken out above, and (c) is taken out the refrigerant outflow pipe 11b.

[Brief description of the drawings]

FIG. 1A is a structural diagram of an accumulator according to a first embodiment of the present invention, and FIG. 1B is a graph showing a pressure change in each corresponding part.

FIG. 2 is a schematic diagram of a vapor compression refrigeration cycle.

FIG. 3 is a structural diagram of an accumulator according to a second embodiment of the present invention.

FIG. 4 is a structural view of an accumulator according to another embodiment of the present invention.

FIG. 5 is a structural diagram of a conventional accumulator used for a refrigeration cycle of a CFC-based refrigerant.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Radiator 3 Expansion valve (decompression means) 4 Evaporator 5 Accumulator 6 Refrigerant inflow pipe 7 End plate (pressure-resistant container) 8 Body (pressure-resistant container) 9 End plate (pressure-resistant container) 11 Refrigerant outflow pipe (refrigerant outflow member) 11a Refrigerant inflow port 11b Refrigerant outflow pipe 11c Oil return hole 12 Cylindrical part (refrigerant outflow member)

Claims (4)

[Claims] 1. A vapor compression refrigeration cycle comprising a compressor (1), a radiator (2), a pressure reducing means (3), an evaporator (4), and an accumulator (5). A) a refrigerant inflow pipe (6) for introducing the gas-liquid two-phase refrigerant from the above, and a pressure resistance for separating the gas-liquid two-phase refrigerant into gas and liquid by a difference in specific gravity, and storing the gas-liquid separated liquid refrigerant and gaseous refrigerant. Containers (7, 8, 9); Refrigerant outflow members (11, 12) arranged in the pressure-resistant containers (7, 8, 9) for extracting gaseous refrigerant separated from gas and liquid
And a refrigerant outflow pipe (11b) connected to the refrigerant outflow members (11, 12) and leading the gaseous refrigerant from the pressure-resistant container (7, 8, 9) to the compressor (1), The refrigerant inflow port (11) of the refrigerant outflow member (11, 12)
a) is made larger than the passage area of the refrigerant outflow pipe (11b), and the refrigerant outflow member (11, 1) is opened.
An oil return hole (11c) is opened in 2), and the oil in the pressure-resistant container (7, 8, 9) is removed from the refrigerant outflow member (11, 11).
An accumulator characterized in that the accumulator is incorporated in (12). 2. The accumulator according to claim 1, wherein an opening area of the refrigerant inlet (11a) is made larger than a passage area of the refrigerant outlet pipe (11b) by expanding a pipe. 3. The refrigerant outflow member (11, 12) includes a tubular part (12) having an opening at an upper side disposed in the pressure-resistant container (7, 8, 9), and the refrigerant outflow pipe (11). 11b)
The refrigerant outflow pipe (1) further extending into the tubular part (12)
1) and the opening is connected to the refrigerant inlet (11a).
The accumulator according to claim 1, wherein an opening area of the refrigerant inflow port (11a) is larger than a passage area of the refrigerant outflow pipe (11b). 4. In the refrigerant outflow member (11), the refrigerant inflow port (1) extends from the vicinity of the oil return hole (11c).
The cross-sectional area of the part up to 1a) is
4. The accumulator according to claim 1, wherein the passage area is larger than the passage area of b).