Gas cooler

Abstract

To discharge drainage to the outside of a casing efficiently regardless of a passage cross sectional area of a gas passage in the casing at a gas cooler.SOLUTION: A gas cooler includes: a drainage recovery part 33; a drainage discharge passage 34; a drainage tank 40; and a ventilation flow passage 50. In the drainage recovery part 33, drainage, which is separated from a gas by a cooling part 21 cooling the gas, accumulates. The drainage tank 40 has: a separation part 47 where the drainage and the gas are separated; and a storage part 48 in which the separated drainage is stored. The drainage discharge passage 34 communicates with the drainage recovery part 33 at one end and communicates with the separation part 47 at the other end. The ventilation flow passage 50 communicates with the separation part 47 at one end and communicates with a gas passage leading to a downstream side space 37, located above the drainage recovery part 33, and a gas lead-out port 32 at the other end.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a gas cooler. [Background technology]

[0002] In the gas cooler for a compressor disclosed in Patent Document 1, gas introduced into the gas cooler from a gas inlet is cooled by a heat exchanger and discharged from a gas outlet. Liquid (drain) in the gas condensed by cooling accumulates in a drain collection section provided at the bottom of the gas cooler and is discharged to the outside from an opening (drain outlet) provided in the casing of the gas cooler. If the size of the gas flow passage cross-sectional area in the casing and the drain outlet are not set appropriately or cannot be set appropriately due to structural constraints, etc., the drain accumulated in the drain collection section may be entrained in the gas flow and reach, for example, the second stage compressor body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-21759 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to efficiently discharge drain to the outside of a casing in a gas cooler, regardless of the flow path cross-sectional area of ​​a gas flow path in a casing. [Means for solving the problem]

[0005] The present invention provides a drain tank having: a casing provided with a gas inlet and a gas outlet; a cooling section provided inside the casing, dividing the interior of the casing into an upstream space into which the gas inlet opens and a downstream space communicating with the gas outlet, and cooling the gas introduced into the interior of the casing; a drain collection section provided at a bottom of the downstream space, in which drain separated from the gas by cooling the gas in the cooling section accumulates; a separation section into which the drain accumulated in the drain collection section is introduced together with a portion of the gas, and which separates the drain from the gas; a storage section in which the separated drain is stored; and a drain discharge port for discharging the drain from the storage section. The drain collected in the drain collection section is introduced together with a portion of the gas. Provided is a gas cooler comprising: a drain discharge flow path, one end of which is connected to the drain collection section and the other end of which is connected to the separation section; and a ventilation flow path, one end of which is connected to the separation section and the other end of which is connected to a gas flow path that leads to the downstream space above the drain collection section and the gas outlet.

[0006] According to the gas cooler of the present invention, the gas discharged from the compressor body and reaching the drain collection section is separated into a first flow that flows only from the drain collection section through the casing and reaches the gas outlet, and a second flow that passes from the drain collection section through the drain tank and merges with the first flow. The drain that accumulates in the drain collection section is led to the separation section of the drain tank together with the gas by the second flow, so that the drain can be prevented from being accompanied by the first flow and being led to the gas outlet. In addition, the drain that is led to the drain tank together with the gas by the second flow is separated into gas and drain in the separation section, the separated drain accumulates in the storage section, and the separated gas merges with the first flow through the ventilation flow path. Therefore, the drain can be prevented from being accompanied by the second flow and reaching the gas outlet. In addition, the gas led to the inside of the drain tank returns to the gas flow path through the ventilation flow path, so that gas loss due to gas leakage can be prevented.

[0007] The gas flow path may include a first gas flow path extending upward from the drain collection section and connecting the downstream space and the gas outlet, and the other end of the ventilation flow path may be connected to the first gas flow path.

[0008] For example, the cross-sectional areas of the first gas flow passage, the separation section, the drain discharge flow passage, and the ventilation flow passage may have the following relationship. TIFF0007597594000001.tif843A1: Cross-sectional area of ​​the first gas flow path A2: Cross-sectional area of ​​the separation section A3: Cross-sectional area of ​​drain discharge flow path A4: Cross-sectional area of ​​the ventilation channel

[0009] The velocities of gas in the first gas flow channel and the separation section may have the following relationship: TIFF0007597594000002.tif1773U:Terminal velocity U1: Gas velocity in the first gas flow path U2: Gas velocity in the separation section V: Flow rate of gas led to the drain collection section V1: Flow rate of gas introduced into the first gas flow path V2: Flow rate of gas introduced into the separation section

[0010] For example, when the casing is an existing part, the value of the flow passage cross-sectional area A1 is fixed. In addition, the value of the flow rate V of the gas discharged from the compressor body and guided to the drain recovery section is also fixed depending on the usage status of the compressor, for example, customer requirements. Even under such conditions, the flow rate V1 of the gas guided to the first gas flow passage is reduced, that is, the flow rate V2 of the gas guided to the separation section is increased, so that the velocity U1 of the gas in the first gas flow passage can be less than the terminal velocity U. In addition, the flow passage cross-sectional areas A2 to A4 of the drain discharge flow passage, the drain tank, and the ventilation flow passage can be set arbitrarily within a range that satisfies the above relationship. Therefore, for example, even if the flow rate V2 is increased by increasing the flow passage cross-sectional area A4, the velocity U2 of the gas in the separation section can be set to less than the terminal velocity U by increasing the flow passage cross-sectional area A2. As a result, since the velocities U1 and U2 can each be less than the terminal velocity U, it is possible to suppress the drain from being entrained in the gas flow and reaching the gas outlet.

[0011] The height position of the inner bottom surface of the drain tank may be relatively lower than the height position of the inner bottom surface of the casing, and the drain discharge flow path may be open on the casing side to include the height position of the inner bottom surface of the casing, and the bottom surface of the drain discharge flow path may be horizontal or have a downward slope toward the drain tank side.

[0012] According to the above-mentioned configuration, the drain can be quickly guided from the drain collection section to the drain tank, thereby reducing the amount of drain remaining in the drain collection section and further preventing the drain from reaching the gas outlet port.

[0013] The gas cooler may include a throttle valve for adjusting the flow rate of gas passing through the ventilation passage.

[0014] According to the above-described configuration, the flow rate V2 can be appropriately set by adjusting the opening of the throttle valve, and the speeds U1 and U2 can be adjusted.

[0015] The gas cooler may include a perforated plate that covers an upper part of the drain stored in the storage portion in the drain tank.

[0016] According to the above configuration, the drain stored in the storage section can be prevented from being lifted by the gas flow, so that the drain can be more effectively prevented from reaching the gas outlet through the ventilation flow path.

[0017] The other end of the ventilation passage may be open to the atmosphere instead of being communicated with the gas outlet port.

[0018] According to the above configuration, even if the second flow cannot be returned to the first flow, the drain can be stored in the storage section. The gas that reaches the drain collection section may be separated into a first flow that flows only within the casing from the drain collection section and reaches the gas outlet, and a second flow that flows from the drain collection section through the drain tank and then merges with the first flow. Effect of the Invention

[0019] According to the gas cooler of the present invention, the drain can be efficiently discharged to the outside of the casing regardless of the flow passage cross-sectional area of ​​the gas flow passage in the casing. [Brief description of the drawings]

[0020] [Figure 1] 1 is a schematic configuration diagram of a compressor according to an embodiment of the present invention; [Diagram 2] 1 is a schematic diagram of a compressor equipped with a gas cooler according to a first embodiment of the present invention. [Diagram 3] FIG. 5 is a schematic diagram of a compressor including a gas cooler according to a second embodiment of the present invention. [Figure 4] FIG. 11 is a schematic diagram showing a modified example of the second embodiment of the present invention. [Diagram 5] FIG. 5 is a schematic diagram of a compressor including a gas cooler according to a third embodiment of the present invention. [Figure 6] FIG. 11 is a schematic diagram of a compressor including a gas cooler according to a fourth embodiment of the present invention. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 11 is a schematic diagram of a compressor including a gas cooler according to a fifth embodiment of the present invention. [Figure 9] FIG. 13 is a schematic diagram of a compressor including a gas cooler according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] (First embodiment) The compressor 1 of this embodiment is an oil-free two-stage screw compressor. The following description will be given taking air as an example of the gas it handles.

[0022] 1, a compressor 1 includes a first stage compressor body 2, a second stage compressor body 3, an intercooler 20, and an aftercooler 60. In this embodiment, the first stage compressor body 2, the intercooler 20, the second stage compressor body 3, and the aftercooler 60 are arranged in this order in an air flow path and are fluidly connected.

[0023] The first stage compressor body 2 draws in air from an intake port 4 that is open to the atmosphere, compresses the air internally, and discharges it from a discharge port 5. The compressed air discharged from the discharge port 5 is sent to an intake port 6 of the second stage compressor body 3 via an intercooler 20.

[0024] 2, an intercooler 20 is interposed between the first-stage compressor body 2 and the second-stage compressor body 3. The intercooler 20 is provided with a cooling section 21. In the cooling section 21, heat exchange occurs between a cooling liquid from the outside and the air discharged from the first-stage compressor body 2, and the air discharged from the first-stage compressor body 2 is cooled. The air before passing through the cooling section 21 is at a high temperature of, for example, about 180°C, but the air in the intercooler 20 after passing through the cooling section 21 is cooled to, for example, about 40°C. Therefore, appropriately cooled compressed air is supplied to the second-stage compressor body 3.

[0025] The second stage compressor body 3 sucks in the compressed air supplied from the intercooler 20, compresses it therein, and discharges it from the discharge port 7. The compressed air discharged from the discharge port 7 is cooled by the cooling section 61 of the aftercooler 60, similar to the intercooler 20, and is supplied to a destination such as a factory.

[0026] In the above configuration, when air is cooled inside the intercooler 20 or the aftercooler 60, moisture in the air condenses, generating drainage water inside each of them. The drainage water may cause malfunctions if it flows into the second stage compressor body 3 or the supply destination along with the air flow, but in this embodiment, the intercooler 20 and the aftercooler 60 each have a structure for removing the drainage water.

[0027] The following describes the structure for removing the drain in the intercooler 20. In this embodiment, the aftercooler 60 has the same structure as the intercooler 20.

[0028] Referring to FIG. 2, the intercooler 20 (gas cooler) includes a casing 30, a cooling section 21, and a drain tank 40.

[0029] The casing 30 is provided with a gas inlet 31 and a gas outlet 32. The gas inlet 31 is connected to the discharge port 5 of the first stage compressor body 2. The gas outlet 32 ​​is connected to the suction port 6 of the second stage compressor body 3.

[0030] The cooling section 21 is provided inside the casing 30 and divides the inside of the casing 30 into an upstream space 36 in which the gas inlet 31 opens, and a downstream space 37 that communicates with the gas outlet 32 ​​.

[0031] The cooling section 21 cools the air (gas) introduced into the casing 30. Specifically, the air comes into contact with the tube nests 22 and the fins 23 and exchanges heat with the cooling water in the tube nests 22, thereby cooling the air. When the air is cooled, moisture in the air condenses into droplets that fall, generating drainage.

[0032] The casing 30 includes a drain collection section 33 provided at the bottom of the downstream space 37. In the drain collection section 33, drain separated from the air (gas) by cooling the air (gas) in the cooling section 21 accumulates.

[0033] The casing 30 also includes a gas flow passage 38 that communicates with a downstream space 37 above the drain collection section 33 and the gas outlet 32. The gas flow passage 38 extends upward from the drain collection section 33 and includes a first gas flow passage 39 that connects the downstream space 37 and the gas outlet 32.

[0034] The drain tank 40 is a cylindrical hollow tank having a side wall 41, a top wall 42, and a bottom wall 43. The drain tank 40 has a separation section 47 located above the drain tank 40, and a storage section 48 located below the drain tank 40 in which the drain is stored as described below. The boundary between the storage section 48 and the separation section 47 is not fixed, and the gas phase space above the liquid level of the stored drain is the separation section 47. The height H1 of the inner bottom surface 43a of the drain tank 40 is relatively lower than the height H2 of the inner bottom surface 30a of the casing 30. Note that, when the inner bottom surface 30a is not a horizontal flat surface, the height H2 is the lowest position of the inner bottom surface 30a.

[0035] The drain tank 40 also includes a drain discharge flow path 34, one end of which is connected to the drain collection section 33 and the other end of which is connected to the separation section 47. That is, the drain discharge flow path 34 has one end connected to a drain outlet 35 provided in the drain collection section 33 portion of the casing 30, and the other end connected to a drain inlet 49 provided in the separation section 47 portion of the side wall 41.

[0036] After the drain and air pass through the drain discharge flow path 34, the drain accumulated in the drain collection section 33 is introduced together with a portion of the air (gas) into the separation section 47, where the drain and the air (gas) are separated, and the separated drain is stored in the storage section 48. The depth of the storage section 48 is sufficiently deep from the drain inlet 49 so that the drain can be stored without blocking the drain inlet 49.

[0037] A drain outlet 44 for discharging drain from the storage portion 48 is provided in the bottom wall 43. A drain outlet 44 is connected to a drain pipe 45. The drain pipe 45 is connected to an external pipe via a sealing mechanism 46. The sealing mechanism 46 is, for example, a valve such as a solenoid valve.

[0038] The intercooler 20 includes an air flow passage 50 for returning the air in the separation section 47 into the casing 30. One end of the air flow passage 50 is connected to a gas outlet 51 provided in the top wall 42 of the drain tank 40, and the other end is connected to a gas inlet 52 provided in the casing 30 in the portion of the gas flow passage 38. That is, one end of the air flow passage 50 is connected to the separation section 47, and the other end is connected to the gas flow passage 38. In other words, the other end of the air flow passage 50 is connected to the first gas flow passage 39. The gas inlet 52 may be provided in the casing 30 in the portion furthest downstream of the first gas flow passage 39.

[0039] The flow of air and drain will be described in detail below.

[0040] As described above, the compressed air discharged from the discharge port 5 of the first stage compressor body 2 is sent to the suction port 6 of the second stage compressor body 3 via the intercooler 20. In other words, an air flow is generated inside the casing 30 from the gas inlet 31 toward the gas outlet 32.

[0041] In this embodiment, the air flowing from the gas inlet 31 toward the gas outlet 32 ​​is divided into a flow that flows only within the casing 30 and a flow that passes through the drain tank 40. In other words, the air that reaches the drain collection section 33 is divided into a first flow that flows through the first gas flow passage 39 as shown by arrows F1 and F2, and a second flow that passes through the drain tank 40 as shown by arrows F3 and F4.

[0042] The drainage accumulated in the drainage recovery section 33 is quickly guided to the separation section 47 together with the air by the second flow.

[0043] The drainage water guided to the separation section 47 together with the air is separated from the air and stored in the storage section 48 by its own weight. The air separated in the separation section 47 merges with the first gas flow path 39 via the ventilation flow path 50 as shown by the arrow F4. The drainage water stored in the storage section 48 is discharged from the drain discharge port 44 by opening the sealing mechanism 46 as necessary. That is, the sealing mechanism 46 is controlled to open and close only to discharge the drainage water stored in the storage section 48. That is, the opening and closing control of the sealing mechanism 46 is not necessary to guide the drainage water from the drainage collection section 33 to the separation section 47.

[0044] In addition, if the sealing mechanism 46 is opened so as to maintain the drain stored in the storage section 48, air cannot leak from the sealing mechanism 46, and therefore opening and closing control of the sealing mechanism 46 to minimize air leakage is not necessary. For example, a first water level sensor 70 that detects that the drain has decreased to a predetermined lower limit level of the storage section 48 is provided in the lower half (for example, near H1) between heights H1 and H3, and a second water level sensor 71 that detects that the drain has increased to a predetermined upper limit level of the storage section 48 is provided in the upper half (for example, near H3) between heights H1 and H3. Then, the controller 72 may control opening and closing so that the sealing mechanism 46 (solenoid valve) is closed when the first water level sensor 70 detects that the drain storage amount has reached the lower limit level, and the sealing mechanism 46 (solenoid valve) is opened when the second water level sensor 71 detects that the drain storage amount has reached the upper limit level. The first water level sensor 70 and the second water level sensor 71 may be replaced by a single water level sensor capable of continuously detecting the water level from the lower limit level to the upper limit level. In place of the second water level sensor 71, a timer capable of setting any time from when the first water level sensor 70 detects that the drain storage amount has reached the lower limit level to when the drain reaches the upper limit level may be provided, and opening and closing control may be performed to open the sealing mechanism 46 (solenoid valve) when a predetermined set time has been counted. The sealing mechanism is not limited to a solenoid valve, and may be a free-float type air trap 46a (see FIG. 3). The free-float type air trap 46a does not require electrical opening and closing control itself, so that automatic drain discharge is possible without opening and closing control.

[0045] As a result of the above, the air that reaches the drain collection section 33 flows only within the casing 30 from the drain collection section 33 and is divided into a first flow that reaches the gas outlet 32, and a second flow that flows from the drain collection section 33 through the drain tank 40 and then joins the first flow.

[0046] The drain collected in the drain collection section 33 is guided to the separation section 47 of the drain tank 40 together with the air by the second flow, so that the drain can be prevented from being accompanied by the first flow and being guided to the second-stage compressor body 3. In addition, the drain guided to the drain tank 40 together with the air by the second flow is separated into air and drain in the separation section 47, the separated drain is accumulated in the storage section 48, and the separated air is passed through the ventilation flow path 50 and merges with the first flow. Therefore, the drain can be prevented from being accompanied by the second flow and reaching the second-stage compressor body 3. In addition, the air guided to the inside of the drain tank 40 returns to the gas flow path 38 through the ventilation flow path 50, so that air loss due to air leakage can be prevented.

[0047] As described above, according to the gas cooler of the present embodiment, the drainage can be efficiently discharged to the outside of the casing 30 regardless of the flow path cross-sectional area of ​​the gas flow path in the casing 30. In addition, the drainage can be discharged to the outside of the casing 30 without the need for opening and closing control of the sealing mechanism 46 for discharging the drainage to the outside of the casing 30 and for minimizing air leakage.

[0048] 2, the flow of air and drain will be described in detail below with reference to the flow path cross-sectional area A1 of the first gas flow path 39, the flow path cross-sectional area A2 of the separation section 47, the flow path cross-sectional area A3 of the drain discharge flow path 34, and the flow path cross-sectional area A4 of the ventilation flow path 50. The flow path cross-sectional area refers to the cross-sectional area of ​​each flow path that is approximately perpendicular to the direction in which the fluid flows when the fluid passes through each flow path. The flow path cross-sectional area A2 of the separation section 47, which is a gas phase space, is the area of ​​the horizontal cross section of the inner wall of the drain tank 40 in the separation section 47.

[0049] In this embodiment, the cross-sectional areas A1 to A4 of the first gas flow passage 39, the separation section 47, the drain discharge flow passage 34, and the ventilation flow passage 50 satisfy the relationship of the following formula (1).

[0050]

number

[0051] Since the flow path cross-sectional area A2 is set to be sufficiently larger than the flow path cross-sectional area A1, even if the air velocity is equal to or greater than the terminal velocity U in the first gas flow path 39, it can be less than the terminal velocity U in the separation section 47. Here, the terminal velocity U refers to the maximum velocity that droplets reach when freely falling in the air in balance with the air resistance, and may be set to, for example, about 5 m / sec.

[0052] Since the flow path cross-sectional area A3 is sufficiently larger than the flow path cross-sectional area A4, the drainage accumulated in the drainage recovery section 33 can be quickly guided to the separation section 47 together with the air by the second flow.

[0053] As described above, the flow path cross-sectional area A3 is large enough to quickly guide the drain accumulated in the drain collection section 33 to the separation section 47, while being smaller than the flow path cross-sectional area A1, thereby improving ease of installation. In other words, for example, it may become easier to provide the drain tank 40 or the like in the existing casing 30.

[0054] 2, the velocity U1 of the air (gas) in the first gas flow passage 39, the velocity U2 of the air (gas) in the separation section 47, the flow rate V1 of the air (gas) introduced into the first gas flow passage 39, and the flow rate V2 of the air (gas) introduced into the separation section 47 will be described below. Note that in this specification, the term "flow rate" refers to a "volumetric flow rate (unit: m 3 / seconds).

[0055] In this embodiment, the velocities of the air (gas) in the first gas flow passage 39 and the separation section 47 satisfy the relationship of the following formulas (2) to (4).

[0056]

number

[0057]

number

[0058]

number

[0059] For example, when the casing 30 is an existing part, the value of the flow passage cross-sectional area A1 is fixed. In addition, the value of the flow rate V of the air discharged from the first stage compressor body 2 and guided to the drain recovery section 33 is also fixed depending on the usage conditions of the compressor 1, for example, customer requirements.

[0060] Even under such conditions, by reducing the flow rate V1 of air led to the first gas flow path 39, i.e., by increasing the flow rate V2 of air led to the separation section 47, the air velocity U1 in the first gas flow path 39 can become less than the terminal velocity U.

[0061] Furthermore, the flow path cross-sectional areas A2 to A4 of the drain discharge flow path 34, the drain tank 40, and the ventilation flow path 50 can be set arbitrarily within a range that satisfies the above relationship. Therefore, for example, even if the flow rate V2 is increased by increasing the flow path cross-sectional area A4, the air velocity U2 in the separation section 47 can be set to be less than the terminal velocity U by increasing the flow path cross-sectional area A2.

[0062] As a result, the speed U1 and the speed U2 can each be less than the terminal speed U, so that the drain can be prevented from being entrained in the air flow and reaching the second stage compressor body 3.

[0063] Hereinafter, the second to sixth embodiments of the present invention will be described. These embodiments are similar to the first embodiment unless otherwise specified. In addition, in the drawings of these embodiments, the same elements as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment.

[0064] Second embodiment 3, in the intercooler 20 of the second embodiment, the height H3 of the bottom surface 34a of the drain discharge passage 34 is the same as the height H2 of the inner bottom surface 30a of the casing 30. That is, the drain discharge passage 34 opens on the casing 30 side so as to include the position H2 in the height direction of the inner bottom surface 30a of the casing 30, and the bottom surface 34a of the drain discharge passage 34 is horizontal. Also, in the intercooler 20 of the second embodiment, a free-float type air trap 46a is provided instead of the sealing mechanism 46.

[0065] In the second embodiment, resistance to the flow of drain from the drain collection section 33 to the drain tank 40 is reduced, and the drain can be guided quickly. This reduces retention of drain in the drain collection section 33, and further prevents the drain from reaching the gas outlet 32. In addition, the free-float type air trap 46a does not require electrical opening and closing control, and therefore allows drain to be automatically discharged without opening and closing control.

[0066] As shown in FIG. 4, in the modified example of the second embodiment, a bottom surface 34a of the drain discharge flow passage 34 is inclined downward toward the drain tank 40 side.

[0067] In the modified example of the second embodiment, a downward force due to gravity is also applied, so that the drain can be guided to the drain tank 40 more quickly.

[0068] Third embodiment 5, the intercooler 20 in the third embodiment includes a throttle valve 53 that adjusts the flow rate of gas passing through the ventilation passage 50.

[0069] The throttle valve 53 has a function of adjusting the flow rate of air passing through the ventilation flow path 50. Therefore, by adjusting the opening degree of the throttle valve 53, the flow rate V2 can be appropriately set, and the speeds U1 and U2 can be adjusted.

[0070] (Fourth embodiment) 6 and 7, the intercooler 20 in the fourth embodiment includes a perforated plate 54 that covers the upper part of the drain stored in the storage portion 48 in the drain tank 40. The perforated plate 54 is a thin plate having a plurality of small holes 54a. For example, the perforated plate 54 may be a member obtained by perforating a metal plate, such as a so-called punching metal, or may be a member obtained by perforating a resin plate having a specific gravity lighter than that of the drain water.

[0071] The method of installing the perforated plate 54 is not particularly limited, and it may be fixed at a predetermined depth position in the storage section 48, or it may simply be placed on the bottom of the storage section 48 so that it floats when the drain accumulates in the storage section 48.

[0072] By providing the perforated plate 54, the drainage stored in the storage section 48 can be prevented from being lifted by the air flow, thereby further preventing the drainage from reaching the gas outlet 32 ​​via the ventilation passage 50.

[0073] Fifth embodiment 8, in the fifth embodiment, the other end of the ventilation passage 50 is not connected to the gas outlet port 32 but is open to the atmosphere.

[0074] In the fifth embodiment, even if the second flow cannot be returned to the first flow, the drain can be stored in the storage section.

[0075] Sixth embodiment 9, in the sixth embodiment, the tip (other end) of the ventilation passage 50 is not connected to the casing 30 and is open to the atmosphere. In addition, the intercooler 20 in the sixth embodiment includes a throttle valve 53 that adjusts the flow rate of gas passing through the ventilation passage 50.

[0076] The throttle valve 53 has a function of adjusting the flow rate of air passing through the ventilation flow path 50. Therefore, by adjusting the opening degree of the throttle valve 53, the flow rate V2 can be appropriately set, and the speeds U1 and U2 can be adjusted.

[0077] Moreover, in the sixth embodiment, even if the second flow cannot be returned to the first flow, the drain can be stored in the storage section 48. Moreover, simply by adjusting the flow rate of air passing through the ventilation flow passage 50, that is, by adjusting the loss of air, it is possible to prevent the drain from being entrained in the first flow and being led to the gas outlet 32.

[0078] Although the specific embodiment of the present invention and its modified examples have been described above, the present invention is not limited to the above-mentioned embodiment, and various modifications can be made within the scope of the present invention. For example, the casing 30, the drain discharge passage 34, the drain tank 40, and the ventilation passage 50 may each be formed by an individual member, or at least two or more may be integrally formed like a casting. In addition, although the case where the inner bottom surface 30a of the casing 30 is horizontal has been exemplified, the inner bottom surface 30a may be formed to be lowered continuously or stepwise toward the drain outlet 35. [Explanation of symbols]

[0079] 1 Compressor 2. First stage compressor body 3. Second stage compressor body 4,6 Intake port 5,7 Outlet 20 Intercooler 21,61 Cooling section 22,62 tube nest 23,63 Fin 30 Casing 31 Gas inlet 32 Gas outlet 33 Drain recovery section 34 Drain discharge passage 35 Drain outlet 36 Upstream space 37 Downstream space 38 Gas flow path 39 First gas flow path 40 Drain tank 41 Side wall 42 Top Wall 43 Bottom wall 44 Drain outlet 45 Drain discharge pipe 46 Sealing mechanism 46a Air trap (sealing mechanism) 47 Separation part 48 Storage section 49 Drain inlet 50 Ventilation channel 51 Gas outlet 52 Gas inlet 53 Throttle valve 54 Perforated plate 60 Aftercooler 70,71 Water level sensor 72 Controller

Claims

1. a casing provided with a gas inlet and a gas outlet; a cooling section provided inside the casing, dividing the interior of the casing into an upstream space in which the gas inlet opens and a downstream space communicating with the gas outlet, and cooling the gas introduced into the interior of the casing; a drain recovery section provided at a bottom of the downstream space, in which drain separated from the gas by cooling the gas in the cooling section accumulates; a drain tank having a separation section into which the drain accumulated in the drain collection section is introduced together with a portion of the gas and which separates the drain from the gas, a storage section in which the separated drain is stored, and a drain outlet for discharging the drain from the storage section; a drain discharge flow path having one end connected to the drain collection section and the other end connected to the separation section so that the drain accumulated in the drain collection section is introduced together with a portion of the gas; a ventilation flow path having one end connected to the separation section and the other end connected to a gas flow path that is connected to the downstream space above the drain collection section and the gas outlet; A gas cooler.

2. the gas flow path includes a first gas flow path extending upward from the drain collection portion and connecting the downstream space and the gas outlet port, The gas cooler according to claim 1 , wherein the other end of the ventilation passage is connected to the first gas passage.

3. 3. The gas cooler according to claim 2, wherein the cross-sectional areas of the first gas flow passage, the separation section, the drain discharge flow passage, and the ventilation flow passage satisfy the following relationship: A1: Cross-sectional area of ​​the first gas flow path A2: Cross-sectional area of ​​the flow path of the separation section A3: Cross-sectional area of ​​the drain discharge flow path A4: Cross-sectional area of ​​the ventilation flow path

4. 4. The gas cooler according to claim 3, wherein the velocities of the gas in the first gas flow passage and the separation section have the following relationship: U: Terminal velocity U1: gas velocity in the first gas flow path U2: Gas velocity in the separation section V: Flow rate of gas guided to the drain recovery section V1: flow rate of gas introduced into the first gas flow path V2: Flow rate of gas introduced into the separation section

5. a height direction position of the inner bottom surface of the drain tank is relatively lower than a height direction position of the inner bottom surface of the casing; 5. The gas cooler according to claim 1, wherein the drain discharge passage is open on the casing side so as to include a position in a height direction of the inner bottom surface of the casing, and the bottom surface of the drain discharge passage is horizontal or has a downward slope toward the drain tank side.

6. 6. The gas cooler according to claim 1, further comprising a throttle valve for adjusting the flow rate of gas passing through the ventilation passage.

7. The gas cooler according to claim 1 , further comprising a perforated plate that covers an upper portion of the drain stored in the storage portion in the drain tank.

8. 8. The gas cooler according to claim 1, wherein the other end of the ventilation passage is open to the atmosphere instead of being connected to the gas outlet port.

9. A gas cooler as described in any one of claims 1 to 8, wherein the gas that reaches the drain collection section flows only within the casing from the drain collection section and is separated into a first flow that reaches the gas outlet, and a second flow that flows from the drain collection section through the drain tank and then joins the first flow.

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