JP2007212020A - Oil separator and refrigerating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve oil separation efficiency of an oil separator by blocking the flow of a gas from which oil is not separated, generated in the demister type oil separator. <P>SOLUTION: In this demister type oil separator comprising a casing, a fluid inlet pipe 5 disposed in a state of penetrating through the casing, a fluid outlet pipe 6 disposed at an upper part of the fluid inlet pipe 5 in a state of penetrating through the casing, and a net-like demister member 10 disposed between the fluid inlet pipe 5 and the fluid outlet pipe 6 in the casing and fitted to the casing, baffle portions 11, 12 blocking the flow of fluid from which the oil is not separated, are mounted on a plate member 13 for fixing the demister member 10 in the casing of the oil separator. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an oil separator having a demister member between a fluid inlet pipe and a fluid outlet pipe of a casing, and a refrigeration apparatus including the oil separator.

  Conventionally, an oil separator has been used as a device for separating oil from gas accompanied with mist-like oil. The oil separator has an oil separation member for separating oil from gas in the container. As a conventional technique related to this oil separator, Patent Document 1 discloses a demister type oil separator using a demister member as an oil separation member. Hereinafter, a conventional demister type oil separator (1) will be described with reference to the drawings. FIG. 4 shows an upper longitudinal sectional view of a conventional demister type oil separator (1), and FIG. 5 shows a schematic view of a general demister type oil separator (1).

  First, the structure of this demister type oil separator (1) will be described. The demister type oil separator (1) includes a casing (9) and three connection pipes (5, 6, 7).

  The casing (9) is joined to the cylindrical body (4), the upper end plate (3) joined to the upper end opening of the body (4), and the lower end opening of the body (4). The lower end plate (2) is formed into a vertically long cylindrical sealed container. A fluid inlet pipe (5) passes through the upper side of the body (4), a fluid outlet pipe (6) passes through the center of the upper end panel (3), and an oil return pipe (7) passes through the center of the lower end panel (2). Is provided. Then, as shown in FIG. 4, a demister member (10) is fitted inside the vertically long cylindrical casing (9). The demister member (10) is formed into a cylindrical shape by twisting thin metal wires to form a belt-like mesh member and winding the member a predetermined number of times. The demister member (10) is disposed between the fluid inlet pipe (5) and the fluid outlet pipe (6) of the demister type oil separator (1). A mesh-shaped demister fixing plate (8, 8a) joined to the inner wall surface of the casing (9) is arranged vertically so as to sandwich the demister member (10), and holds the demister member (10). ing.

Next, the operation of the demister type oil separator (1) will be described. A gas with mist-like oil flows into the container from the fluid inlet pipe (5) of the oil separator and passes through the inside of the demister member (10) on the downstream side. During the passage, the mist-like oil is captured by the thin metal wire constituting the demister member (10) and separated from the gas. The gas from which the mist-like oil has been separated flows out through the fluid outlet pipe (6) as it is. On the other hand, the amount of trapped mist oil captured by the demister member (10) increases with time, and the oil particles grow gradually. ) And is discharged outside through the oil return pipe (7).
JP-A-6-235572

  By the way, the demister type oil separator (1) has a problem that the oil separation efficiency tends to be lowered. This problem is caused by a gap or a low density region in the demister type oil separator (1) due to its structure. This gap or low density region tends to occur between the outermost part of the demister member (10) and the inner wall surface of the casing (9), or at the center of the demister member (10). The reason for the former gap (b) is that the demister type oil separator (1) has a structure in which the demister member (10) is fitted inside the casing (9), and the demister member (10) This is because there may be a dimensional difference between the diameter and the inner diameter of the casing (9). On the other hand, the reason why the latter gap (low density region (a)) can be formed is that the demister which is the beginning of winding of the band in the demister member (10) formed into a cylindrical shape by winding the band-shaped mesh member a predetermined number of times. This is because the winding diameter of the central portion of the member (10) is smaller than that of the peripheral edge and is difficult to wind. The gas flowing into these gaps or low-density regions (a) flows out of the vessel without being separated by the demister member (10), and the oil separation efficiency is increased when the flow rate of this gas increases. It will drop. The gas flowing through the center of the demister member (10) passes through the interior at a higher flow rate than other parts because the fluid outlet pipe (8) is located at the center of the upper end plate (3). The oil separation efficiency at the center is further reduced.

  The present invention has been made in view of this point, and an object of the present invention is to make it possible to oil-separate gas that passes through a gap or a low-density region (a) generated in a demister-type oil separator (1). Therefore, it is to increase the oil separation efficiency of the oil separator.

  The first invention includes a casing (9), a fluid inlet pipe (5) provided through the casing (9), and a casing (9) provided above the fluid inlet pipe (5). And a mesh-shaped demister member (5) disposed between the fluid inlet pipe (5) and the fluid outlet pipe (6) in the casing (9) and fitted into the casing (9) ( 10) is assumed.

  And in this casing (9) of this oil separator, the plate member (11) provided with the central baffle part (11) which blocks the flow of fluid in the central part of the demister member (10) on the upper surface side of the demister member (10) 13) is provided.

  In this first aspect of the invention, the plate member (13) provided with the central baffle portion (11) causes the gas flowing through the gap (low density region) (a) in the central portion of the demister member (10) to flow through the central baffle. While colliding with the part (11), the gas flow direction can be changed toward the high density region.

  The second invention is premised on the same oil separator as the oil separator described as the premise in the first invention.

  And in the casing (9) of this oil separator, the plate provided with the peripheral baffle part (12) which prevents the flow of the fluid in the peripheral part of the demister member (10) on the upper surface side of the demister member (10) A member (13) is provided.

  In the second aspect of the invention, the gas flowing through the gap (b) in the peripheral portion of the demister member (10) is transferred to the peripheral baffle portion (12) by the plate member (13) having the peripheral baffle portion (12). It is possible to prevent the collision and to change the gas flow direction toward the high density region.

  The third invention is premised on the same oil separator as the oil separator described as the premise in the first invention.

  And in the casing (9) of this oil separator, on the upper surface side of the demister member (10), a central baffle portion (11) and a demister member ( The plate member (13) provided with the peripheral baffle part (12) which blocks | prevents the flow of the fluid in the peripheral part of 10) is provided, It is characterized by the above-mentioned.

  In the third aspect of the invention, the plate member (13) having the central baffle portion (11) and the peripheral baffle portion (12) is used to provide a gap (low density region) (a) in the central portion of the demister member (10). The gas flowing through the center baffle (11) and the gas flowing through the peripheral gap (b) collide with the peripheral baffle (12) to prevent it, and the flow direction of both gases is directed to the high density region. Each can be changed.

  4th invention presupposes the same oil separator as the oil separator described as a premise in 1st invention.

  And in the casing (9) of this oil separator, the plate provided with the baffle part (11) for fluid outlet pipes which blocks the flow of the fluid of the portion facing the fluid outlet pipe (6) in the demister member (10) A member (13) is provided.

  In the fourth aspect of the invention, the gas flowing in the portion facing the fluid outlet pipe (6) on the upper surface of the demister member (10) is obtained by the plate member (13) provided with the baffle portion (11) for the fluid outlet pipe. While colliding with the baffle part (11) for fluid outlet pipes, it is possible to change the gas flow direction toward the high density region.

  According to a fifth invention, in the first, third, or fourth invention, the casing (9) is constituted by a vertical cylindrical container, and the fluid outlet pipe (6) is provided at the center of the top of the casing (9). It is characterized by being installed.

  In the fifth aspect of the invention, by installing the fluid outlet pipe (6) at the center of the top of the casing (9), the center of the demister member (10) out of the gas directed to the demister member (10). The gas flowing through the demister member (10) passes at a higher flow rate.

  A sixth invention includes a demister fixing plate (8) for fixing the demister member (10) in the casing (9) in any one of the first to fifth inventions, the demister fixing plate (8) being It is characterized by comprising a plate member (13).

  In the sixth aspect of the invention, the demister fixing plate (8) is composed of a plate member (13) having a baffle portion (11, 12), so that the demister fixing plate (8) is a demister member (10). In addition to fixing the gas, the gas flowing through the gap or low density area (a, b) inside the demister type oil separator (1) collides with each baffle (11, 12) and is blocked. The gas flow direction can be changed toward the high density region.

  The seventh invention includes a refrigerant circuit (104) that includes a plurality of compressors (14a, 14b, 14c) connected in parallel to each other and performs a refrigeration cycle, and each compressor (14a, 14b, 14c) An oil separator (1) connected to the discharge side junction pipe (34), and a plurality of oil return pipes connecting the oil separator (1) and the suction side of each compressor (14a, 14b, 14c) (21, 21a, 21b, 21c) and a refrigerating apparatus provided with an open / close mechanism (SV2, SV3, SV4) provided in each oil return pipe (21a, 21b, 21c).

  And this oil separator (1) is comprised by the oil separator as described in any one of 1st-6th invention, It is characterized by the above-mentioned.

  In the seventh invention, the oil separator (1) can be used in the refrigerant circuit (104) of the refrigeration apparatus (101).

  According to the first invention, in the oil separator using the demister member (10) configured in a mesh shape, the plate member (13 having the central baffle portion (11) on the upper surface side of the demister member (10). The oil separation efficiency of the oil separator can be improved. The reason is that by providing the plate member (13), the flow of gas that does not contribute to the improvement of the oil separation efficiency can be prevented, and the gas flow can be made a flow that contributes to the improvement of the oil separation efficiency. Because. Here, the gas flow that does not contribute to the improvement of the oil separation efficiency means that the oil is not separated through the gap (a) generated in the central portion of the demister member (10), that is, a so-called meshless portion or a portion having a small mesh density. This is a gas flow, and the flow of the gas not separated by oil is blocked by colliding with the central baffle portion (11), and the flow direction is changed to change the mesh in the vicinity of the central portion of the demister member (10). By passing a certain portion (high density region), the oil separation efficiency of the oil separator can be improved.

  According to the second aspect of the invention, in the oil separator using the demister member (10) configured in a mesh shape, the plate having the peripheral baffle portion (12) on the upper surface side of the demister member (10). By providing the member (13), the oil separation efficiency of the oil separator can be improved. The reason is that by providing the plate member (13), the flow of gas that does not contribute to the improvement of the oil separation efficiency is prevented and the gas flow is improved for the oil separation efficiency as in the first invention. It is because it can be set as the flow which contributes. Here, the gas flow that does not contribute to the improvement of the oil separation efficiency is a gap (b) generated for fitting between the outermost part of the demister member (10) and the inner wall surface of the casing (9), so-called mesh. This is a flow of gas that is not separated by oil that passes through a portion where no oil is separated. The flow of gas that is not separated by oil is prevented from colliding with the peripheral baffle portion (12), and the flow direction is changed to change the flow direction of the demister member ( The oil separation efficiency of the oil separator can be improved by passing the part having a mesh (high density region) in the vicinity of the peripheral part of 10).

  According to the third aspect of the invention, in the oil separator using the demister member (10) configured in a mesh shape, the central baffle portion (11) and the peripheral baffle portion on the upper surface side of the demister member (10). By providing the plate member (13) provided with (12), the oil separation efficiency of the oil separator can be improved. The reason is that by providing the plate member (13), the flow of gas that does not contribute to the improvement of the oil separation efficiency is prevented and the gas flow is improved for the oil separation efficiency as in the first invention. It is because it can be set as the flow which contributes. Here, the gas flow that does not contribute to the improvement of the oil separation efficiency refers to the gap (a) generated at the center of the demister member (10) and the outermost part of the demister member (10) and the inner wall surface of the casing (9). This is a non-oil-separated gas flow that passes through a low-density region such as a gap (b) generated between them. Of this non-oil-separated gas flow, a gap (a) that occurs at the center of the demister member (10) The gas flowing through the center baffle (11) collides with the peripheral baffle (12) through the gap (b) generated between the outermost part of the demister member (10) and the inner wall of the casing (9). The oil separation efficiency of the oil separator can be improved by blocking and allowing the passage direction of the demister member (10) to pass through a meshed portion (high density region).

  According to the fourth aspect of the invention, in the oil separator using the demister member (10) configured in a mesh shape, the baffle portion (11) for the fluid outlet pipe is provided on the upper surface side of the demister member (10). By providing the plate member, the oil separation efficiency of the oil separator can be improved. The reason is that by providing the plate member (13), the flow of gas that does not contribute to the improvement of the oil separation efficiency can be prevented, and the gas flow can be made a flow that contributes to the improvement of the oil separation efficiency. Because. Here, the gas flow that does not contribute to the improvement of the oil separation efficiency is a gas flow that passes through the portion facing the end face of the fluid outlet pipe (6) in the demister member (10) at a high flow velocity and is difficult to separate oil. The flow of gas difficult to separate oil is blocked by colliding with the baffle portion (11) for the fluid outlet pipe, and the flow is decelerated and changed in direction to change the direction of the fluid outlet pipe (6 of the demister member (10)). The oil separation efficiency of the oil separator can be improved by passing a meshed portion (high density region) in the vicinity of the portion facing the end face of ().

  According to the fifth aspect, in the oil separator according to the first, third or fourth aspect, the fluid outlet pipe (6) of the oil separator (1) is connected to the center of the top of the casing (9). If installed in the section, the flow velocity of the gas flowing through the gap (a) in the center near the fluid outlet pipe (6) is further accelerated. However, this accelerated gas flow can be blocked at the central baffle (11) and the flow can be changed.

  Further, according to the sixth aspect, since the demister fixing plate (8) also has the function of the plate member (13), it is not necessary to newly provide a dedicated plate member.

  Further, according to the seventh invention, by installing the demister type oil separator (1) of the present invention in the refrigeration apparatus, the oil is efficiently separated from the gas accompanying the oil on the mist from the compressor, The oil can be stored in the lower space of the demister type oil separator (1).

Embodiment 1 of the Invention
Hereinafter, a demister type oil separator (1) (oil separator) according to Embodiment 1 of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a top longitudinal sectional view of the demister type oil separator (1), and FIG. 5 is a schematic view of the demister type oil separator (1). Here, in FIG. 1, the low density area | region which arises inside a demister member (10) is set to a, and it shows with the area | region between 2 dashed-dotted lines. As shown in FIG. 5, the demister type oil separator (1) includes a casing (9) and three connection pipes (5, 6, 7).

  The casing (9) includes a cylindrical body (4), a bowl-shaped upper end plate (3) joined to the upper end opening of the body (4) by welding, and a lower end of the body (4) It is comprised from the eaves-like lower end plate (2) joined to the opening by welding into a vertically long cylindrical sealed container. And the fluid inlet pipe (5) as a connecting pipe on the upper side surface of the body (4) of the casing (9), the fluid outlet pipe (6) as a connecting pipe at the center of the upper end panel (3), and the lower end panel An oil return pipe (7) as a connection pipe is provided through the center of (2).

  As shown in FIG. 1, a demister member (10) that is an oil separating member, a plate member (13), and a lower demister fixing plate (8a) are accommodated in the casing (9).

  The demister member (10) is formed into a cylindrical shape by twisting one or more thin metal wires to form a belt-like mesh member and winding the member a predetermined number of times. The number of turns is appropriately increased or decreased according to the desired separation efficiency. In general, the greater the number of turns, the greater the number of times the gas contacts the metal wire of the demister member, thus increasing the degree of trapping mist-like oil contained in the gas and increasing the separation efficiency.

  The lower demister fixing plate (8a) is located between the fluid inlet pipe (5) and the demister member (10), and is joined to the cylindrical body (4). And the shape is comprised with the metal circular net | network, and the space | interval of the mesh | network is set wider than this demister member (10) so that gas may flow into a demister member (10) easily.

  The plate member (13) is positioned between the fluid outlet pipe (6) and the demister member (10), and is joined to the bowl-shaped upper end plate (3). As shown in FIG. 2, the shape is a circular plate having a central baffle portion (11) and a peripheral baffle portion (12) which are also features of the present invention. The cross-shaped cross portion of the plate member (13) in FIG. 2 constitutes the central baffle portion (11), and the ring-shaped plate outside the cross-shaped plate constitutes the peripheral baffle portion (12). Yes.

  The demister member (10) is sandwiched and fixed between the plate member (13) and the lower demister fixing plate (8a).

  Next, the operation of the demister type oil separator (1) will be described. The gas with mist-like oil flows into the sealed container from the fluid inlet pipe (5) and flows toward the demister member (10) on the downstream side thereof. Here, out of the gas directed to the demister member (10), the gap (low density region) (a) in the center of the demister member (10) is flown at a higher flow rate by the central installation of the fluid outlet pipe (6). The gas that flows through the gap (b) between the outermost part of the demister member (10) and the inner wall surface of the casing (9) collides with the peripheral baffle part (12). Then, the flow direction is changed by the collision and flows into the meshed portion (high density region) of the demister member (10) in the vicinity thereof. On the other hand, gases other than those that collide with the baffle portions (11, 12) flow directly into the meshed portion (high density region) of the demister member (10). When passing through the inside of the demister member (10), the mist-like oil is captured by the thin metal wire constituting the demister member (10) and separated from the gas. The gas from which the mist-like oil has been separated flows out through the fluid outlet pipe (6) as it is. On the other hand, the mist-like oil captured by the demister member (10) falls downward due to its own weight, is stored in the lower space of the demister-type oil separator (1), and is discharged outside by the oil return pipe (7). Is done.

-Effect of Embodiment 1-
According to the first embodiment, in the demister type oil separator (1), the gas that does not contribute to the improvement of the oil separation efficiency generated in the demister type oil separator (1) by using the plate member (13). The flow of gas can be made a flow that contributes to the improvement of oil separation efficiency. Here, the gas flow that does not contribute to the improvement of the oil separation efficiency is the gap (a) (low density region) generated in the center of the demister member (10), the outermost part of the demister member (10), and the casing (9). This is a gas flow that does not separate oil and passes through the gap (b) generated between the inner wall of the demister and the gas flowing in the gap (a) (low density region) generated in the center of the demister member (10). A gas flowing through a gap (b) generated between the outermost part of the demister member (10) and the inner wall surface of the casing (9) is caused to collide with the peripheral baffle part (12) on the central baffle part (11). In addition to blocking and changing the flow direction and passing the part of the demister member (10) with a mesh (high density region), it can be a flow that contributes to improving the oil separation efficiency of the oil separator. The oil separation efficiency is improved. Moreover, since the oil separation efficiency is improved, the height of the demister member (10) located in the upper space of the demister type oil separator (1) can be kept low, so that the lower space is widened accordingly. More oil can be held in the lower space.

<< Embodiment 2 of the Invention >>
Since the demister type oil separator (1) shown in the first embodiment can hold more oil, it is used as a component of the oil return circuit (105) of the refrigeration apparatus (101) shown in the second embodiment. can do. Hereinafter, Embodiment 2 of the present invention will be described in detail with reference to the drawings.

  FIG. 3 is a refrigerant circuit diagram of the refrigeration apparatus (101) according to the second embodiment. In this refrigeration apparatus (101), one external unit (110) and two internal units (60) installed in parallel are connected by a liquid side connecting pipe (102) and a gas side connecting pipe (103). This is a so-called separate type refrigeration apparatus (101), and is configured to cool the inside of a refrigerated warehouse.

  The outside unit (110) has an outside circuit (111) and an oil return circuit (105) having a demister type oil separator (1), which is a feature of the present invention, and each inside unit (60) has an inside chamber. Each circuit (61) is provided. In this refrigeration apparatus (101), a refrigerant circuit (104) that performs a vapor compression refrigeration cycle by connecting an internal circuit (61) in parallel with pipes (102, 103) to an external circuit (111). ) Is configured.

  A first closing valve (112) and a second closing valve (113) are provided at the end of the external circuit (111). One end of a liquid side communication pipe (102) is connected to the first closing valve (112). The other end of the liquid side connecting pipe (102) branches into two, and each is connected to the liquid side end of the internal circuit (61). One end of a gas side communication pipe (103) is connected to the second closing valve (113). The other end of the gas side connecting pipe (103) is branched into two, and each is connected to the gas side end of the internal circuit (61).

《Outside unit》
The external circuit (111) of the external unit (110) includes an oil return circuit (105), a compression mechanism (14), an external heat exchanger (15), a receiver (16), a supercooling heat exchanger (17 ), A first external expansion valve (18), a second external expansion valve (19), and a four-way switching valve (20). The compression mechanism (14) is configured by connecting a variable capacity compressor (14a), a first fixed capacity compressor (14b), and a second fixed capacity compressor (14c) in parallel.

  Each of the variable capacity compressor (14a), the first fixed capacity compressor (14b), and the second fixed capacity compressor (14c) is constituted by, for example, a fully-sealed and high-pressure dome type scroll compressor. . Electric power is supplied to the variable capacity compressor (14a) via an inverter. The capacity of the variable capacity compressor (14a) can be changed by changing the rotation speed of the electric motor by changing the output frequency of the inverter. On the other hand, in the first fixed capacity compressor (14b) and the second fixed capacity compressor (14c), the electric motor is always operated at a constant rotational speed, and the capacities thereof cannot be changed.

  A first discharge branch pipe (21a) is disposed on the discharge side of the variable capacity compressor (14a), and a second discharge branch pipe (21b) is disposed on the discharge side of the first fixed capacity compressor (14b). A third discharge branch pipe (21c) is connected to the discharge side of the capacity compressor (14c). The first discharge branch pipe (21a) has a check valve (CV1), the second discharge branch pipe (21b) has a check valve (CV2), and the third discharge branch pipe (21c) has a check valve ( CV3) is provided. The other ends of these discharge branch pipes (21a, 21b, 21c) are connected to the demister type oil separator (1) via a discharge junction pipe (21) (see the fluid inlet pipe (5) of the first embodiment). )It is connected to the. These check valves (CV1, CV2, CV3) are provided to allow refrigerant flow from the compression mechanism (14) to the discharge junction pipe (21) while prohibiting refrigerant flow in the reverse direction. It has been.

  On the other hand, one end of the first suction branch pipe (22a) is provided on the suction side of the variable capacity compressor (14a), and one end of the second suction branch pipe (22b) is provided on the suction side of the first fixed capacity compressor (14b). However, one end of the third suction branch pipe (22c) is connected to the suction side of the second fixed capacity compressor (14c). The other ends of these suction branch pipes (22a, 22b, 22c) are connected to the four-way switching valve (20) via a suction junction pipe (22).

  The oil return circuit (105) includes a demister type oil separator (1), a solenoid valve (SV2, SV3, SV4) and one oil return junction pipe (34) as shown by the thick line in FIG. (See the oil return pipe (7) of Embodiment 1) and the first, second and third oil return branch pipes (34a, 34b, 34c).

  One end of the first oil return branch pipe (34a) is connected to the first suction branch pipe (22a), one end of the second oil return branch pipe (34b) is connected to the second suction branch pipe (22b), and the third oil return branch pipe. One end of (34c) is connected to the third suction branch pipe (22c), and the other ends of the three oil return branch pipes (34a, 34b, 34c) are all connected to the oil return junction pipe (34). Has been. The oil return junction pipe (34) is connected to the demister type oil separator (1). Each oil return branch pipe (34a, 34b, 34c) is provided with first, second and third solenoid valves (SV2, SV3, SV4), respectively.

  The external heat exchanger (15) is a cross fin type fin-and-tube heat exchanger, and constitutes a heat source side heat exchanger. An external fan (23) is provided in the vicinity of the external heat exchanger (15). Although not shown, in the external heat exchanger (15), the heat transfer tubes are arranged in a plurality of paths, and the refrigerant pipes are branched and connected to the heat transfer tubes of the respective paths. In the external heat exchanger (15), heat exchange is performed between the external air blown by the external fan (23) and the refrigerant flowing inside the heat transfer tube. One end of the external heat exchanger (15) is connected to the four-way switching valve (20). On the other hand, the other end of the external heat exchanger (15) is connected to the top of the receiver (16) via the first liquid pipe (24).

  The supercooling heat exchanger (17) includes a high-pressure channel (17a) and a low-pressure channel (17b), and exchanges heat between the refrigerants flowing through the channels (17a, 17b). This supercooling heat exchanger (17) is constituted by, for example, a plate heat exchanger.

  The inflow end of the high-pressure channel (17a) is connected to the bottom of the receiver (16). The outflow end of the high-pressure channel (17a) is connected to the first closing valve (112) via the second liquid pipe (25). On the other hand, the inflow end of the low-pressure channel (17b) is connected to the first branch pipe (26) branched from the second liquid pipe (25) which is a high-pressure liquid line downstream of the supercooling heat exchanger (17). The first branch pipe (26) is connected to the first outside expansion valve (18) which is a pressure reducing control valve. This 1st outside expansion valve (18) is comprised with the electronic expansion valve which can adjust an opening degree. The outflow end of the low-pressure channel (17b) is connected to an intake gas pipe (27) that communicates with the intake junction pipe (22) of the compression mechanism (14).

  The receiver (16) is installed between the external heat exchanger (15) and the supercooling heat exchanger (17) as described above, and can temporarily store the high-pressure refrigerant condensed in the heat exchanger. It is like that. One end of the gas vent pipe (28) is connected to the upper part of the receiver (16), and the other end is connected to the first discharge branch pipe (21a) via a check valve (CV7). Here, the check valve (CV7) is attached in such a direction as to allow the refrigerant to flow from the receiver (16) to the discharge junction pipe (21) of the compression mechanism (14).

  The refrigerant circuit (104) includes a gas injection passage (30) for performing gas injection to the suction side of the compression mechanism (14). The gas injection passage (30) is connected to the first branch pipe (26) and a supercooling heat exchanger (17) which is a refrigerant vaporizing mechanism which communicates with the first branch pipe (26) and vaporizes the decompressed refrigerant. The low pressure side flow path (17b) and the suction gas pipe (27) are configured.

  One end of the second branch pipe (28) is connected to the second liquid pipe (25) between the connection portion of the first branch pipe (26) and the first closing valve (112). The other end of the second branch pipe (28) is connected between the external heat exchanger (15) and the receiver (16) in the first liquid pipe (24).

  A third branch pipe (29) that bypasses the receiver (16) and the supercooling heat exchanger (17) is connected between the first liquid pipe (24) and the second liquid pipe (25). The third branch pipe (29) is provided with the second external expansion valve (19). The second external expansion valve (19) is an electronic expansion valve whose opening degree can be adjusted, and constitutes a heat source side expansion valve.

  Between the connection part of the 3rd branch pipe (29) and the connection part of the 2nd branch pipe (28) in the said 1st liquid pipe (24), only the flow of the refrigerant | coolant to the direction toward a receiver (16) is carried out. An allowable check valve (CV4) is provided. Further, between the connecting portion of the first branch pipe (26) and the connecting portion of the second branch pipe (28) in the second liquid pipe (25), the direction toward the liquid side connecting pipe (102) is set. A check valve (CV5) that allows only the flow of refrigerant is provided, and the check valve (CV6) that allows only the flow of refrigerant in the direction toward the receiver (16) is provided in the second branch pipe (28). Is provided.

  The four-way selector valve (20) has the first port (P1) as the discharge junction pipe (21), the second port (P2) as the suction junction pipe (22), and the third port (P3) as the outside heat. A fourth port (P4) is connected to the second closing valve (113) in the exchanger (15). The four-way selector valve (20) is in a first state in which the first port (P1) and the third port (P3) communicate with each other and the second port (P2) and the fourth port (P4) communicate with each other (see FIG. 1 and a second state (FIG. 1) in which the first port (P1) and the fourth port (P4) communicate with each other and the second port (P2) and the third port (P3) communicate with each other. In a state indicated by a broken line in FIG.

  Various sensors and pressure switches are also provided in the external circuit (111). Specifically, the suction junction pipe (22) is provided with a suction temperature sensor (35) and a suction pressure sensor (36). The first discharge branch pipe (21a) is provided with a first high pressure switch (37) and a first discharge gas temperature sensor (38). The second discharge branch pipe (21b) is provided with a second high pressure switch (39) and a second discharge gas temperature sensor (40). The third discharge branch pipe (21c) is provided with a third high pressure switch (41) and a third discharge gas temperature sensor (42). Each high-pressure switch (37, 39, 41) detects the discharge pressure, and urgently stops the refrigeration apparatus (101) as a protection device when the pressure is abnormally high. A discharge pressure sensor (43) is provided at a location where the first discharge branch pipe (21a), the second discharge branch pipe (21b), and the third discharge branch pipe (21c) are connected to the discharge junction pipe (21). ing. In addition, an outside air temperature sensor (44) is provided in the vicinity of the outside fan (23) of the outside heat exchanger (15). The second liquid pipe (25) is provided with a liquid temperature sensor (45).

  Each of the sensors (38, 40, 42, 43, 44, 45) and the switches (37, 39, 41) are connected to a controller (50) that controls the operation of the refrigeration apparatus (101). This controller (50) has a compression mechanism (14), a four-way selector valve (in accordance with the output of each sensor (40, 38, 40, 42, 43, 44, 45) and switch (37, 39, 41). 20) Controls the electronic expansion valves (18, 19) and solenoid valves (SV1 to SV4).

<Inside unit>
The two internal units (60) are configured in the same manner. In the internal circuit (61) of each internal unit (60), the drain pan heating pipe (62), the internal expansion valve (63), and the internal heat exchange in that order from the liquid side end to the gas side end A vessel (64) is provided.

  The internal expansion valve (63) is an electronic expansion valve whose opening degree can be adjusted, and constitutes a use side expansion valve. The internal heat exchanger (64) is a cross fin type fin-and-tube heat exchanger, and constitutes a use side heat exchanger. An internal fan (65) is provided in the vicinity of the internal heat exchanger (64). Although not shown, in the internal heat exchanger (64), the heat transfer tubes are arranged in a plurality of paths, and the refrigerant pipes are branched and connected to the heat transfer tubes of the respective paths. And in this internal heat exchanger (64), heat exchange is performed between the internal air which the said internal fan (65) ventilates, and the refrigerant | coolant which flows the inner side of a heat exchanger tube.

  A drain pan (66) is provided below the internal heat exchanger (64). This drain pan (66) collects frost and condensed water falling from the surface of the internal heat exchanger (64). The drain pan heating pipe (62) is a refrigerant pipe arranged along the bottom surface of the drain pan (66). This drain pan heating pipe (62) melts frost collected in the drain pan (66) and ice blocks generated by freezing droplets in the drain pan (66) using the heat of the refrigerant. is there.

  The internal circuit (61) is provided with three temperature sensors. Specifically, an evaporation temperature sensor (67) is provided in the heat transfer tube of the internal heat exchanger (64). A gas temperature sensor (68) is provided in the vicinity of the gas side end of the internal circuit (61). In the vicinity of the internal fan (65), an internal temperature sensor (69) is provided.

-Driving action-
Next, the operation of the refrigeration apparatus (101) of Embodiment 2 will be described.

<Cooling operation>
In the cooling operation of the refrigeration apparatus (101), the internal unit (60) cools the interior.

  During the cooling operation, in the external circuit (111), the first port (P1) and the third port (P3) of the four-way selector valve (20) communicate with each other, and the second port (P2) and the fourth port (P4). Is set to communicate. Further, the opening degree of the first external expansion valve (18) is adjusted as appropriate, while the second external expansion valve (19) is fully closed. In the internal circuit (61), the opening degree of the internal expansion valve (63) is appropriately adjusted. In the cooling operation, at least one of the compressors (14a, 14b, 14c) is operated. In the refrigerant circuit (104), the external heat exchanger (15) serves as a condenser, and each internal heat exchanger (64) serves as an evaporator, and a refrigeration cycle having a flow indicated by a solid line arrow is performed. .

  The low-pressure gas refrigerant sucked into each compressor (14a, 14b, 14c) is compressed to a predetermined high-pressure gas to become high-pressure gas refrigerant, and the discharge branch pipes (21a, 21b, 21c) are non-returned. Pass through the valves (CV1, CV2, CV3). These check valves (CV1, CV2, CV3) are connected to the discharge branch pipes (21a, 21b, 21c) of the compressors (14a, 14b, 14c) stopped for a certain refrigeration load, for example, from the operating compressor The gas refrigerant functions so that it does not flow backward. The high-pressure gas refrigerant joins in the discharge junction pipe (21) without flowing back to other compressors, and is sent to the demister type oil separator (1) to separate the refrigeration oil in the refrigerant. It flows into the external heat exchanger (15) through the switching valve (20).

  In the external heat exchanger (15), the high-pressure gas refrigerant dissipates heat to the external air and condenses. The high-pressure liquid refrigerant condensed in the external heat exchanger (15) flows into the receiver (16) through the first liquid pipe (24). This high-pressure liquid refrigerant absorbs the increase and decrease of the refrigerant when the amount of refrigerant retained in the external heat exchanger (15) and the internal heat exchanger (64) increases or decreases due to changes in the operating state or the refrigeration load state. The receiver (16) flows out while being temporarily stored in the receiver (16). The refrigerant flowing out of the receiver (16) flows into the high pressure side flow path (17a) of the supercooling heat exchanger (17) and releases the heat to the low pressure side flow path (17b). 17) spill.

  The refrigerant that has flowed out of the supercooling heat exchanger (17) passes through the liquid side connecting pipe (102) and is distributed to each internal circuit (61). The refrigerant flowing into the internal circuit (61) flows through the drain pan heating pipe (62). Here, the drain pan (66) stores frost that has fallen from the surface of the internal heat exchanger (64) and ice blocks that are generated by freezing the condensed water after collection. For this reason, when the vicinity of the drain pan (66) is heated by the refrigerant flowing through the drain pan heating pipe (62), frost and ice blocks in the drain pan (66) are melted. The water that has become liquid as described above is discharged from the drain pan (66) as drain waste water.

  On the contrary, the refrigerant flowing through the drain pan heating pipe (62) is cooled by frost and ice blocks in the drain pan (66) taking heat of melting. As a result, the refrigerant flowing through the drain pan heating pipe (62) is further subcooled.

  The refrigerant that has flowed out of the drain pan heating pipe (62) passes through the internal expansion valve (63) and is decompressed, and then flows through the internal heat exchanger (64). In the internal heat exchanger (64), the refrigerant absorbs heat from the internal air and evaporates. As a result, the air in the refrigerator warehouse is cooled.

  The respective refrigerants evaporated in the internal heat exchangers (64) join together in the gas side connecting pipe (103). The refrigerant merged in the gas side communication pipe (103) passes through the four-way switching valve (20) and flows into the suction merge pipe (22). This refrigerant is mixed with the refrigerant evaporated in the low pressure side flow path (17b) of the above-described supercooling heat exchanger (17), and the first variable capacity compressor (14a) and the first and second fixed capacity compressors ( 14b, 14c). The refrigerant circulation described above is repeated, and in this refrigeration apparatus (101), the air in the freezer warehouse is cooled.

<Defrost operation>
In the refrigeration apparatus (101), when the internal heat exchanger (64) is frosted during the refrigeration operation, the defrost operation is performed to remove the frost. During the defrosting operation, the internal heat exchangers (64) are defrosted simultaneously.

  In the external circuit (111) during the defrost operation, the four-way selector valve (20) is set to the second state. Moreover, while the 1st external expansion valve (18) will be in a fully closed state, the opening degree of a 2nd external expansion valve (19) is adjusted suitably. In the internal circuit (61), the internal expansion valve (63) is fully opened. During the defrost operation, at least one of the compressors is operated. In the refrigerant circuit (104), the external heat exchanger (15) serves as an evaporator, and each internal heat exchanger (64) serves as a condenser, and a refrigeration cycle having a flow indicated by a dashed arrow is performed. . And this cycle is repeated and the frost which adhered to the internal heat exchanger (64) of the internal unit (60) is melted and removed.

<Oil return operation>
Here, the operation of the oil return circuit (105) including the demister type oil separator (1), which is a feature of the present invention, will be described.

  The oil return circuit (105) uses the oil stored in the lower space of the demister-type oil separator (1) without using the oil equalizing pipe that connects the compressors (14a, 14b, 14c) to each other. By controlling the opening and closing operation of the solenoid valves (SV2, SV3, SV4) installed in the second and third oil return branch pipes (34a, 34b, 34c), each compressor (14a, 14b , 14c). First, at the same time that the stopped compressors (14a, 14b, 14c) start operating, the controller (50) adds up the operating time of each compressor (14a, 14b, 14c). When the accumulated operation time reaches a predetermined time, it is determined that the oil level has fallen below the specified amount in the compressor, and corresponds to the compressor (14a, 14b, 14c) that has reached the predetermined time. The solenoid valve (SV2, SV3, SV4) communicating with the oil return branch pipe (34a, 34b, 34c) opens, and the compressor passes through the oil return branch pipe (34a, 34b, 34c) from the demister type oil separator (1). The oil is returned to (14a, 14b, 14c). Here, since the oil level detection of the compressor is estimated by the accumulated operation time, when returning the oil, it is necessary to surely return the oil without drifting, so only one solenoid valve is opened. Yes, the open operation holding time is determined according to the high-low pressure difference during the compressor operation. That is, the opening operation holding time is short when the high / low pressure difference is large, and conversely, it is long when it is small.

-Effect of Embodiment 2-
According to the second embodiment, the oil return circuit (105) of the refrigeration apparatus (101) uses the demister type oil separator (1), which is a feature of the present invention, so that each oil leveling pipe is not used. The compressors (14a, 14b, 14c) can be leveled to the standard oil level. Further, since no oil equalizing pipe is used, the cost of the oil return circuit (105) can be reduced.

<< Other Embodiments >>
About the said Embodiment 1, it is good also as the following structures.

  For example, the plate member (13) used for the demister type oil separator (1) in Embodiment 1 does not include the central baffle portion (11) and the peripheral baffle portion (12), but the central baffle portion (11). Only the peripheral baffle portion (12) may be used.

  Further, the plate member (13) of the present invention may be constituted not only by the upper demister fixing plate (8) but also by the lower demister fixing plate (8a). Furthermore, the fluid outlet pipe (6) may be installed at a place other than the central part at the top of the casing (9). In that case, a baffle portion may be provided at a position corresponding to the fluid outlet pipe (6).

  In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

  As described above, the present invention is useful for the demister type oil separator (1).

It is an upper part longitudinal section of a demister type oil separator. It is a front view of the plate member of the oil separator in Embodiment 1. 6 is a refrigerant circuit diagram of a refrigeration apparatus in Embodiment 2. FIG. It is an upper part longitudinal cross-sectional view of the conventional demister type oil separator. It is the schematic of a demister type oil separator.

Explanation of symbols

1 Demister type oil separator (oil separator)
2 Lower panel
3 Upper panel
4 Torso
5 Fluid inlet pipe
6 Fluid outlet pipe
7 Oil return piping
8 Upper demister fixing plate (demister fixing plate)
8a Lower demister fixing plate
9 Casing
10 Demister material
11 Central baffle
12 Peripheral baffle
13 Plate member
101 Refrigeration equipment
104 Refrigerant circuit

Claims (7)

A casing (9), a fluid inlet pipe (5) provided through the casing (9), and a fluid outlet pipe (through the casing (9) above the fluid inlet pipe (5) ( 6) and a mesh-shaped demister member (10) disposed between the fluid inlet pipe (5) and the fluid outlet pipe (6) in the casing (9) and fitted to the casing (9). In the oil separator,
In the casing (9), a plate member (13) having a central baffle portion (11) for preventing the flow of fluid in the central portion of the demister member (10) is provided on the upper surface side of the demister member (10). An oil separator characterized by that. A casing (9), a fluid inlet pipe (5) provided through the casing (9), and a fluid outlet pipe (through the casing (9) above the fluid inlet pipe (5) ( 6) and a mesh-shaped demister member (10) disposed between the fluid inlet pipe (5) and the fluid outlet pipe (6) in the casing (9) and fitted to the casing (9). In the oil separator,
In the casing (9), a plate member (13) having a peripheral baffle portion (12) for preventing fluid flow in the peripheral portion of the demister member (10) is provided on the upper surface side of the demister member (10). An oil separator characterized by that. A casing (9), a fluid inlet pipe (5) provided through the casing (9), and a fluid outlet pipe (through the casing (9) above the fluid inlet pipe (5) ( 6) and a mesh-shaped demister member (10) disposed between the fluid inlet pipe (5) and the fluid outlet pipe (6) in the casing (9) and fitted to the casing (9). In the oil separator,
In the casing (9), on the upper surface side of the demister member (10), there is a central baffle part (11) for blocking the flow of fluid in the central part of the demister member (10) and fluid in the peripheral part of the demister member (10). The oil separator is provided with a plate member (13) provided with a peripheral baffle portion (12) for preventing the flow of oil. A casing (9), a fluid inlet pipe (5) provided through the casing (9), and a fluid outlet pipe (through the casing (9) above the fluid inlet pipe (5) ( 6) and a mesh-shaped demister member (10) disposed between the fluid inlet pipe (5) and the fluid outlet pipe (6) in the casing (9) and fitted to the casing (9). In the oil separator,
In the casing (9), there is provided a plate member (13) having a fluid outlet pipe baffle portion (11) for blocking the flow of fluid in a portion of the demister member (10) facing the fluid outlet pipe (6). An oil separator characterized by that. In claim 1, 3 or 4,
The casing (9) is constituted by a vertical cylindrical container,
An oil separator, wherein the fluid outlet pipe (6) is installed at the center of the top of the casing (9). In any one of claims 1 to 5,
A demister fixing plate (8) for fixing the demister member (10) in the casing (9);
An oil separator, wherein the demister fixing plate (8) is composed of a plate member (13). A refrigerant circuit (104) that performs a refrigeration cycle with a plurality of compressors (14a, 14b, 14c) connected in parallel to each other;
An oil separator (1) connected to a confluence pipe (34) on the discharge side of each compressor (14a, 14b, 14c), the oil separator (1) and each compressor (14a, 14b, 14c) Equipped with a plurality of oil return pipes (21, 21a, 21b, 21c) connecting to the suction side, and open / close mechanisms (SV2, SV3, SV4) provided in each oil return pipe (21a, 21b, 21c) A refrigeration device,
The said oil separator (1) is comprised with the oil separator as described in any one of Claim 1 to 6, The freezing apparatus characterized by the above-mentioned.

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