JP4839741B2 - Decompressor - Google Patents

Description

  The present invention relates to a decompression device for decompressing and maintaining a space to be decompressed (referred to as a decompression target space) at a predetermined decompression degree.

  2. Description of the Related Art Conventionally, decompression devices for exhausting a decompression target space to decompress and maintain a predetermined decompression degree have been used in various fields such as drying, evaporation, degassing, vacuum packaging, and vacuum packaging. Generally, the decompression target space is sealed, and after the decompression target space is decompressed to a predetermined degree of decompression, the exhaust amount for maintaining the decompression need not be so large. For this reason, one exhaust device such as a vacuum pump used for decompression is usually used, and the exhaust device is connected to the decompression target space by piping.

  By the way, there are some decompression target spaces that cannot be sealed and a considerable inflow of outside air cannot be avoided. When depressurizing such a space to be depressurized, a large amount of exhaust for depressurization is required even if the degree of depressurization is not lowered much (for example, even when depressurizing only about 10 Kpa from atmospheric pressure). For this reason, with one exhaust device, the decompression target space may not reach a predetermined degree of decompression unless the exhaust capability of the exhaust device is significantly increased. Therefore, in that case, as shown in FIG. 5, a plurality of exhaust devices 5 are connected in parallel to the decompression target space 1 via a pipe 2, a valve 3, a branch pipe 4, etc. Dealing with the increased exhaust capacity through parallel operation. In addition, 6 is a pressure gauge which shows the pressure in the pressure reduction object space 1. FIG.

  However, when a plurality of exhaust devices 5 are connected in parallel and operated in parallel in this way, the plurality of exhaust devices 5 interfere with each other, and the original performance of each exhaust device 5 is not fully exhibited, and the exhaust There was a problem that the capacity could not be increased as much as the number of devices installed, and the efficiency was poor. In addition, an exhaust blower, a vacuum pump, an aspirator or the like is used as the exhaust device 5, but when an exhaust device of a type that generates pressure fluctuation (pulsation) during exhaust is used, the pressure fluctuation generated by the exhaust device is reduced. It may act on the decompression / decompression target space 1 and may adversely affect the decompression target space 1. In addition, depending on the decompression target space 1, not only air but also liquid such as water droplets may be mixed in the exhaust from the decompression target space 1, and in that case, the liquid may be sucked into the exhaust device and cause trouble. It was.

The present invention has been made in view of such a situation, and it is possible to efficiently depressurize a space to be depressurized that requires considerable exhaust capacity for depressurization to a predetermined depressurization degree using a plurality of exhaust devices, and also an object to provide a vacuum device which can maintain a little reduced pressure target space may affect the pressure variation in a predetermined vacuum degree in vacuum the space in the case of using those resulting pressure fluctuations as the exhaust system . Another object of the present invention is to provide a decompression device that prevents the liquid from being sucked into the exhaust device even when the liquid is mixed in the exhaust from the decompression target space.

The invention according to claim 1 to solve the above-mentioned problem is a buffer tank connected via a pipe to a space to be decompressed and maintained at a predetermined decompression degree , and is provided in the buffer tank. A buffer tank provided with a shielding plate that separates liquid from the exhaust gas when the exhaust gas sucked from the decompression target space collides between the inlet port and the outlet port , and dedicated pipes for the buffer tank. The gist of the present invention is a decompression device having a plurality of exhaust devices that are connected to each other and perform parallel operation .

The invention according to claim 2 is the invention according to claim 1, wherein the liquid separated in the buffer tank can be automatically discharged to the bottom of the buffer tank with the inside of the buffer tank decompressed. A drain discharge device connected to the drain tank connected to the bottom of the buffer tank, and the drain tank connected to the drain tank so that the liquid level in the drain tank is kept constant. It is configured to have an S-shaped pipe for discharging the liquid flowing into the drain tank out of the system .

The decompression device of the present invention has a configuration in which an exhaust device is connected to a space to be decompressed via a buffer tank, so that the exhaust device generates pressure fluctuation (pulsation) during exhaust, for example, a diaphragm pump Even when a positive displacement exhaust device such as the above is used, the pressure fluctuation generated in the exhaust device is eliminated by the buffer tank, so that it does not affect the decompression target space, and therefore the pressure fluctuation occurs in the decompression target space. There is nothing. In addition, since the plurality of exhaust devices are connected to the buffer tank via dedicated pipes, the plurality of exhaust devices do not interfere with each other, and thus the exhaust capability of each exhaust device is exhibited as it is. Therefore, the space to be decompressed can be efficiently decompressed and maintained at a predetermined degree of decompression by the plurality of exhaust devices. Further, since the buffer tank is provided with a shielding plate for separating the liquid from the exhaust, even if liquid is mixed in the exhaust from the decompression target space, the liquid is separated by the buffer tank and sucked into the exhaust device. It will not be. For this reason, it is possible to avoid the trouble that liquid is sucked into the exhaust device and the exhaust device is damaged.

Here, the bottom of the bar Ffatanku, the liquid separated in the buffer tank an automatic drainable drainage device out of the system while reducing the pressure in the buffer tank, drain tank connected to the bottom of the buffer tank A drain discharge device connected to the drain tank and having an S-shaped pipe for discharging the liquid flowing into the drain tank out of the system so as to keep the liquid level in the drain tank constant. In this way , the liquid separated in the buffer tank can be automatically discharged out of the system while the decompression device continues to operate and the liquid level in the drain tank is kept constant . Therefore, it is not necessary to temporarily stop the operation of the apparatus, and therefore it is possible to continuously operate for a long period of time.

  FIG. 1 is a flowchart schematically showing a decompression device according to a preferred embodiment of the present invention, FIG. 2 is a schematic sectional view of a buffer tank used in the decompression device, and FIG. 3 is connected to the bottom of the buffer tank. It is a schematic sectional drawing of a drain discharge means, and attaches | subjects the same code | symbol to the same components as a conventional apparatus. In FIG. 1 to FIG. 3, a decompression device generally denoted by reference numeral 11 is for decompressing and maintaining the decompression target space 1 at a predetermined decompression degree, and includes a pipe 2 and a valve connected to the decompression target space 1. 3, a buffer tank 12 connected to the pipe 2, a plurality of exhaust devices 5 each connected to the buffer tank 12 via a dedicated pipe 13, and a drain discharge connected to the bottom of the buffer tank 12 The apparatus 14 etc. are provided.

The buffer tank 12 is for absorbing pressure fluctuations (pulsations) generated during exhausting by the exhaust device 5, and the pressure fluctuations generated by the exhaust devices 5 during the parallel operation of the plurality of exhaust devices 5 are reduced. The tank capacity is set so that it does not affect so much. Further, the buffer tank 12 has a structure including a gas-liquid separation function for separating liquid such as water droplets contained in the exhaust from the exhaust sucked from the decompression target space 1. Specifically, a shielding plate 16 is provided in the buffer tank 12 between the inflow port 12a and the outflow port 12b, and the liquid is separated from the airflow when the sucked airflow collides with the shielding plate 16. that it has come to be.

  The drain discharge device 14 connected to the bottom of the buffer tank 12 is capable of automatically discharging the liquid separated in the buffer tank 12 out of the system in a state where the inside of the buffer tank is depressurized. Connected to the drain tank 20 with an indicator 20a, an S-shaped pipe 21 connected to the bottom of the drain tank 20, a valve 22 provided at the tip, and the like. Here, the position of the top of the S-shaped pipe 21 is between the liquid level 24b at the top of the S-shaped pipe 21 when the liquid level 24a of the liquid 24 accommodated in the drain tank 20 is set to a predetermined height H. The liquid level difference h corresponding to the difference between the pressure in the buffer tank 12 and the atmospheric pressure is set. As a result, when the pressure in the buffer tank 12 acts on the drain tank 20, the liquid flows into the drain tank 20 from the buffer tank 12, and when the liquid level 20a exceeds a predetermined height H, the liquid automatically Therefore, the liquid level 20a in the drain tank 20 is always maintained at the height H.

  The plurality of exhaust devices 5 are each connected to the buffer tank 12 via a dedicated pipe 13. In this way, by connecting each exhaust device 5 directly to the buffer tank 12 having a large capacity, it is possible to avoid mutual interference of the plurality of exhaust devices 5 and to fully exhibit the exhaust capability of each exhaust device 5. . Here, as the exhaust device 5, an arbitrary device such as an exhaust blower, a vacuum pump, an aspirator or the like can be used. As the vacuum pump, a positive displacement type that generates pressure fluctuation (pulsation) during exhaust, such as a diaphragm pump. Even if is used, the exhaust capability can be fully exhibited. Further, since the plurality of exhaust devices 5 do not interfere with each other, the present invention is not limited to the case of using the exhaust devices 5 having the same specification, and those having different exhaust capabilities and those having different structures can be used in combination. . In order to connect the plurality of exhaust devices 5 to the buffer tank 12, as shown in FIG. 4, it is conceivable to connect the plurality of exhaust devices 5 via a branch pipe 26. The adjacent exhaust devices 5 interfere with each other and cannot fully exhibit their capabilities. Particularly, when the exhaust capacity of the adjacent exhaust devices 5 is different or when the exhaust device 5 exhausts with pressure, the adjacent exhaust devices 5 It has been found that interference between the devices 5 occurs greatly. Therefore, in order to avoid this phenomenon, as shown in FIG. 1, each exhaust device 5 is configured to be directly connected to the buffer tank 12 using a dedicated pipe 13.

  In the decompression device 11 having the above-described configuration, the plurality of exhaust devices 5 can be operated in parallel to exhaust the decompression target space 1 via the buffer tank 12 to reduce the pressure. Since each exhaust capability can be sufficiently exerted without interfering with the air, a large amount of exhaust can be exhausted and decompressed even in the decompression target space 1 where intrusion of outside air is frequent. At this time, since the buffer tank 12 absorbs pressure fluctuations such as pulsations caused by the exhaust device 5, the decompression target space 1 can be maintained at a constant degree of decompression without pressure fluctuations. In addition, liquid such as water droplets may be mixed in the exhaust from the decompression target space 1, but since the liquid is separated from the air flow when the exhaust passes through the buffer tank 12, the liquid flows into the exhaust device 5. There will be no trouble.

  The liquid separated in the buffer tank 12 flows down to the drain tank 20 and is discharged out of the system. Here, at the start of operation of the decompression device 11, the valve 22 at the tip of the S-shaped pipe 21 is closed so that outside air does not flow into the buffer tank 12 through the S-shaped pipe 21 and the drain tank 20. The liquid flowing down from the buffer tank 12 is accumulated in the drain tank 20, and the depth of the liquid accumulated in the drain tank 20 and the S-shaped pipe 21 is more than a depth that can resist the decompression in the buffer tank 12. At some point, the valve 22 is opened. At this time, as shown in FIG. 3, the liquid level of the liquid accumulated in the drain tank 20 and the S-shaped pipe 21 becomes a position indicated by broken lines 24 c and 24 d, and the liquid level difference h is reduced by the pressure from the buffer tank 12. Because it counters, outside air does not enter. Thereafter, as the liquid flows from the buffer tank 12, the liquid level gradually rises. When the liquid level 20 a of the drain tank 20 reaches a predetermined height H, the liquid level 24 b on the S-shaped pipe 21 side reaches the top of the pipe. As the liquid reaches the drain tank 20 thereafter, the liquid automatically flows out through the S-shaped pipe 21 and the liquid level 20a in the drain tank 20 is always maintained at the height H. Thus, the pressure reduction device 11 can be continuously operated while automatically discharging the liquid separated in the buffer tank 12 out of the system, and the pressure reduction target space 1 can be maintained at a predetermined pressure reduction degree for a long period of time. Although the use object of the above-mentioned decompression device 11 is not particularly limited, the degree of decompression may be as low as about 10 Kpa or less than the atmospheric pressure. However, in order to achieve the degree of decompression, a large amount of exhaust gas is used. It is preferably used for decompression of a space that requires and has such characteristics that liquid components such as water droplets are mixed in the exhaust gas.

  In order to confirm the effect of the decompression device 11 shown in FIG. 1, a decompression target space 1 in which an outside air entrance is formed is prepared, and, as shown in FIG. 1, a buffer tank 12, a drain discharge device 14, a plurality of ( In the test, a decompression device 11 having two exhaust devices 5 and a dedicated pipe 13 was connected to perform a decompression test. The exhaust device 5 used here is a diaphragm pump. Moreover, in order to mix a liquid in exhaust_gas | exhaustion, a small amount of water was blown into the pressure reduction object space 1 with the spray nozzle. A decompression test is performed in which the two exhaust devices 5 of the decompression device 11 are operated in parallel to decompress the decompression target space 1 (Example 1), the degree of decompression and the pressure fluctuation of the decompression target space 1 at that time are measured, and The liquid separation from the exhaust was observed. The results are shown in Table 1.

  For comparison, a decompression device having the configuration shown in FIG. 4 is created using the same decompression target space 1, buffer tank 12, drain discharge device 14 and two exhaust devices 5 as in the first embodiment. A decompression test (Comparative Example 1) in which only the exhaust device 5 is operated to decompress the decompression / decompression target space 1 and a decompression test (Comparative Example 2) in which two exhaust devices 5 are operated in parallel were performed. Further, the conventional decompression device shown in FIG. 5 is configured using the same decompression target space 1 and the two exhaust devices 5 as in the first embodiment, and a decompression test (Comparative Example 3) in which only one exhaust device 5 is operated. ) A decompression test (Comparative Example 4) in which two exhaust devices 5 were operated in parallel was also performed. The results of these decompression tests are also shown in Table 1.

  As can be seen from the results of Table 1, when the exhaust device 5 is connected to the buffer tank 12 via the branch pipe 26 (Comparative Examples 1 and 2), compared with the time of operation of one exhaust device 5, two exhausts Although it is possible to increase the exhaust capacity by operating the apparatus 5 in parallel, the degree of increase is not so large and the efficiency of the parallel operation of two units is poor. On the other hand, in Example 1 in which the two exhaust devices 5 are connected to the buffer tank 12 using the dedicated pipes 13 respectively, the exhaust capacity of the two exhaust devices 5 is considerably large, and the degree of decompression can be increased. . Furthermore, the pressure variation hardly occurred in the space to be decompressed due to the installation of the buffer tank 12. Further, good gas-liquid separation could be performed by the buffer tank 12 having the baffle plate 16. On the other hand, in Comparative Examples 3 and 4 that do not use a buffer tank, the exhaust capacity is higher and the ultimate vacuum is higher than in Comparative Examples 1 and 2 that use a buffer tank, but the capacity increases when two units are operated in parallel. The degree of was not so large, and the ultimate pressure reduction degree of Example 1 could not be obtained. Further, in Comparative Examples 3 and 4, since the buffer tank is not used, the pressure fluctuation of the exhaust device 5 affects the pressure reduction target space 1, and a considerable pressure fluctuation occurs in the pressure reduction target space 1. Thus, the effects of the examples of the present invention were confirmed by these decompression tests.

  The preferred embodiments and examples of the present invention have been described above, but the present invention is not limited to these embodiments and examples, and can be appropriately changed within the scope of the claims. Needless to say.

1 is a flowchart schematically showing a decompression device according to a preferred embodiment of the present invention. Schematic sectional view of the buffer tank of the decompression device shown in FIG. Schematic cross-sectional view of the drain discharge device of the decompression device shown in FIG. A flow chart schematically showing a decompression device having a structure in which the connection path of the exhaust device to the buffer tank is changed from the device of FIG. Flow chart schematically showing a conventional decompression device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pressure reduction object space 2 Piping 3 Valve 4 Branch piping 5 Exhaust device 6 Pressure gauge 11 Pressure reducing device 12 Buffer tank 13 Piping 14 Drain discharge device 16 Shielding plate 18 Piping 19 Valve 20 Drain tank 21 S-shaped piping 22 Valve 26 Branching piping

Claims (2)

A buffer tank connected via a pipe to a decompression target space to be maintained after being decompressed to a predetermined degree of decompression, from the decompression subject space between an inlet and an outlet provided in the buffer tank A buffer tank having a shielding plate that separates liquid from the exhaust gas collided by the sucked exhaust gas , and a plurality of exhaust devices that are connected to the buffer tank via dedicated pipes and perform parallel operation Decompressor. Wherein the bottom of the buffer tank, the liquid separated in the buffer tank and automatic drainable drainage device is connected to the outside of the system while reducing the pressure in the buffer tank, the drain discharge apparatus, the buffer tank A drain tank connected to the bottom of the drain tank, and an S-shaped pipe connected to the drain tank for discharging the liquid flowing into the drain tank out of the system so as to keep the liquid level in the drain tank constant. The decompression device according to claim 1.

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