Differential pressure measuring device and differential pressure measuring method

Abstract

The present invention provides a pressure difference measuring device and a pressure difference measuring method that can accurately measure the pressure difference even when the pressure difference between the ground area and the underground area is small. The differential pressure measuring device (1) is characterized by comprising: a differential pressure measuring unit (11) having a first port (11a) for acquiring the pressure of the above-ground area (100c) and a second port (11b) for acquiring the pressure of the underground area (100d), wherein one end (12a) of a first pipe (12) is connected to the first port (11a) and one end (13a) of a second pipe (13) is connected to the second port (11b); and a cup-shaped member (14) connected to the other end (13b) of the second pipe (13), wherein when disposed on a grid floor (102), a space for measuring the pressure of the underground area (100d) is formed between the device and the grid floor (102), and the distance in the device height direction between the other end (12b) of the first pipe (12) and the other end (13b) of the second pipe (13) is fixed.

Description

Technical Field

[0001] This invention relates to a differential pressure measuring device and a differential pressure measuring method. Background Technology

[0002] Traditionally, semiconductor devices have been manufactured in cleanrooms where the cleanliness level meets specified standards. Cleanrooms typically employ a downflow system where clean air is supplied from the ceiling to the lower level, and the air from the lower level is recycled, purified, and then reintroduced to the ceiling to supply clean air to the lower level again.

[0003] Figure 1 This is a schematic diagram illustrating an example of a cleanroom with a recirculating downflow system. Figure 1 In the cleanroom 100 shown, a clean air supply unit 101, such as an FFU (Fan Filter Unit), is provided in the ceiling 100a to supply clean air. Furthermore, a grid floor 102 with multiple openings 102a is provided in the floor 100b.

[0004] Regarding the supply of clean air, there are two methods: a full-surface downflow method that supplies clean air from the entire surface of the ceiling section 100a, and a partial downflow method that supplies clean air from a portion of the ceiling section 100a. Figure 1 An example is a partial downflow method. Furthermore, regarding the configuration of the grille floor 102, there are cases where it is configured over the entire surface of the floor and cases where it is configured only over a portion of the floor (…). Figure 1 Examples are provided for cases where the configuration is in a partial configuration.

[0005] Furthermore, in the underground area 100d of the cleanroom 100, when the cleanroom 100 is viewed from above, return ports 103 for recovering air discharged into the underground area 100d are provided on each of a pair of opposing walls or in one or more locations throughout the cleanroom 100.

[0006] In this cleanroom 100, clean air supplied from the clean air supply unit 101 passes through the floor area 100c and is discharged to the underground area 100d via an opening 102a provided in the grid floor 102. The discharged air is recovered from the return port 103, purified by a filter (not shown), and guided to the ceiling area 100a by a blower fan 104. Then, clean air is supplied again to the underground area 100d via the clean air supply unit 101. Thus, the clean air is configured to circulate between the ceiling area 100a and the underground area 100d.

[0007] In this cleanroom 100 with this structure, the pressure in the above-ground area 100c becomes a relatively high positive pressure, while the pressure in the underground area 100d becomes a relatively low negative pressure. Therefore, the air flows from top to bottom, which can suppress the upward diffusion of particles.

[0008] In the cleanroom 100 described above, the clean air volume is not uniform throughout the entire floor area 100c, with a higher volume near the return port 103 and a lower volume further away. Ideally, the clean air volume in the cleanroom 100 should be uniform throughout the entire floor area 100c. Therefore, it is necessary to adjust the air supply from the clean air supply unit 101 or the opening ratio of the openings 102a of the grid floor 102 to make the clean air volume uniform.

[0009] When adjusting the airflow of the clean air, the pressure difference between the pressure in the above-ground area 100c and the pressure in the underground area 100d is used as an indicator for adjustment. For example, Patent Document 1 describes a method for measuring the pressure difference between the two ports of a differential pressure measuring device (differential pressure gauge), obtaining the pressure in the above-ground area 100c through one port and the pressure in the underground area 100d through the other port, and adjusting the airflow based on the measured pressure difference.

[0010] Existing technical documents

[0011] Patent documents

[0012] Patent Document 1: Japanese Patent Application Publication No. 2004-218919 Summary of the Invention

[0013] The technical problem that the invention aims to solve

[0014] However, in the method described in Patent Document 1, it was determined that the pressure difference could be accurately measured when the pressure difference was large, but could not be accurately measured when the pressure difference was small (e.g., 0.1 Pa level).

[0015] The present invention was made in view of the above-mentioned technical problems, and its object is to provide a pressure difference measuring device and a pressure difference measuring method that can accurately measure the pressure difference even when the pressure difference between the pressure in the above-ground area and the pressure in the underground area is small.

[0016] Solutions for solving technical problems

[0017] The present invention that solves the above-mentioned technical problems is described below.

[0018] [1] A differential pressure measuring device, which measures the pressure difference between the ground area and the underground area of ​​a room with a grid floor, characterized in that it comprises:

[0019] The differential pressure measuring unit has a first port for obtaining the pressure of the above-ground area and a second port for obtaining the pressure of the underground area, and one end of a first pipe is connected to the first port, and one end of a second pipe is connected to the second port; and

[0020] A cup-shaped component, connected to the other end of the second pipe, when positioned on the grating floor, creates a space between itself and the grating floor for measuring the pressure in the underground area.

[0021] The distance in the height direction between the other end of the first pipe and the other end of the second pipe is fixed.

[0022] [2] According to the differential pressure measuring device described in [1], the distance in the height direction of the device is more than 0 mm and less than 250 mm.

[0023] [3] According to the differential pressure measuring device of [1] or [2], wherein the other end of the first piping is oriented in a direction that intersects the height direction of the device.

[0024] [4] The differential pressure measuring device according to any one of [1] to [3] further comprises a cover that inhibits airflow to the other end of the first piping.

[0025] [5] A differential pressure measurement method, wherein the differential pressure measuring device described in any one of [1] to [4] is disposed on the grid floor of a room on the ground, and the differential pressure between the pressure in the ground area and the pressure in the underground area is measured.

[0026] Invention Effects

[0027] According to the present invention, even when the pressure difference between the pressure in the above-ground area and the pressure in the underground area is small, the pressure difference can be accurately measured. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of an example of a cleanroom with a circulating downflow system.

[0029] Figure 2 This is a cross-sectional view of a preferred example of a differential pressure measuring device based on the present invention.

[0030] Figure 3 This is a diagram illustrating the effect of the differential pressure measuring device based on the present invention.

[0031] Figure 4 This is a diagram illustrating the measurement location of the differential pressure in the embodiment.

[0032] Figure 5 This is a graph showing the relationship between the measurement location and the measured pressure difference in the invention example and the comparative example. Detailed Implementation

[0033] (Differential pressure measuring device)

[0034] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The differential pressure measuring device based on the present invention is a device for measuring the pressure difference between the above-ground area and the underground area of ​​a room with a grid floor. It is characterized by comprising: a differential pressure measuring unit having a first port for acquiring the pressure of the above-ground area and a second port for acquiring the pressure of the underground area, wherein one end of a first pipe is connected to the first port and one end of a second pipe is connected to the second port; and a cup-shaped member connected to the other end of the second pipe. When disposed on the grid floor, a space for measuring the pressure of the underground area is formed between the member and the grid floor, and the distance in the device height direction between the other ends of the first pipe and the other ends of the second pipe is fixed. In other words, the differential pressure measuring device based on the present invention is characterized in that the relative positional relationship in the device height direction between the other ends of the first pipe and the other ends of the second pipe remains constant.

[0035] As described above, in the method described in Patent Document 1, when using a differential pressure measuring device to measure the pressure difference between the above-ground area 100c and the underground area 100d of the cleanroom 100, the measurement cannot be accurate when the pressure difference is small. Based on in-depth research into the reasons why the aforementioned pressure difference cannot be accurately measured, the inventors believe that the airflow of clean air may affect the acquisition of the pressure in the above-ground area 100c and the pressure in the underground area 100d.

[0036] That is, in differential pressure measuring devices, generally speaking, the overall pressure is measured as the sum of the static pressure of the air and the dynamic pressure obtained by converting the kinetic energy of the air into pressure, which is used to measure the differential pressure. Figure 1 In the cleanroom 100 shown, clean air from the above-ground area 100c flows into the underground area 100d through an opening 102a of a partially configured grid floor 102. Therefore, the airflow velocity below the grid floor 102 increases. As described above, in the method described in Patent Document 1, the port for obtaining the pressure of the underground area 100d is located in the underground area 100d below the grid floor 102; therefore, the obtained pressure in the underground area 100d is greatly affected by dynamic pressure.

[0037] However, adjusting the airflow of clean air within the cleanroom 100 requires a pressure difference between the static pressure of the above-ground area 100c and the static pressure of the underground area 100d. Therefore, the inventors conducted in-depth research on methods to reduce the influence of such dynamic pressure when obtaining the pressure of the underground area 100d. As a result, a cup-shaped component was conceived, with one end connected to the port in the differential pressure measuring device used to obtain the pressure of the underground area 100d. Furthermore, it was discovered that when the cup-shaped component is positioned on the grid floor 102, a simulated underground space can be created between the cup-shaped component and the grid floor 102, reducing the influence of the dynamic pressure of the clean air and enabling the obtaining of the pressure of the underground area 100d.

[0038] Furthermore, the inventors believe that when obtaining the pressure of the underground region 100d, one end of a flexible conduit is connected to the port for obtaining the pressure of the above-ground region 100c. However, when obtaining the pressure of the above-ground region 100c, the position of the other end of the conduit is different each time, leading to inconsistencies in the differential pressure value. Therefore, the inventors conceived of fixing the distance in the height direction between the other end of the conduit connected to the port for obtaining the pressure of the above-ground region 100c (first port) and the other end of the conduit connected to the port for obtaining the pressure of the underground region 100d (second port). Thus, the present invention is completed. Hereinafter, the various configurations of the differential pressure measuring device based on the present invention will be described.

[0039] Figure 2 A cross-sectional view of a preferred example of a differential pressure measuring device based on the present invention is shown. Figure 2 The differential pressure measuring device 1 shown includes a differential pressure measuring unit 11, a first piping 12, a second piping 13, a cup-shaped component 14, and a gasket 15.

[0040] The differential pressure measuring unit 11 has a first port 11a for obtaining the pressure of the above-ground region 100c and a second port 11b for obtaining the pressure of the underground region 100d. One end 12a of the first pipe 12 is connected to the first port 11a, and one end 13a of the second pipe 13 is connected to the second port 11b. The differential pressure measuring unit 11 measures the differential pressure from the difference between the pressure obtained in the above-ground region 100c and the pressure in the underground region 100d.

[0041] The differential pressure measuring unit 11 is not particularly limited as long as it can obtain the pressure of the above-ground area 100c and the pressure of the underground area 100d and measure their pressure difference, and can be constructed from a conventionally known differential pressure measuring device (differential pressure gauge). However, since the pressure difference between the above-ground area 100c and the underground area 100d of the cleanroom 100 is small, it is preferable that the differential pressure measuring unit 11 has a resolution of 0.1 Pa or less. With a resolution of 0.1 Pa or less, the pressure difference between the above-ground area 100c and the underground area 100d can be accurately measured.

[0042] The first pipe 12 and the second pipe 13 can be made of soft vinyl chloride, silicone tubing, etc.

[0043] Furthermore, the cup-shaped member 14 is connected to the other end 13b of the second pipe 13. For example... Figure 3 As shown, the cup-shaped member 14 is configured such that when the cup-shaped member 14 is placed on the grid floor 102, a space simulating an underground region 100d is formed between the cup-shaped member 14 and the grid floor 102. With this configuration, the dynamic pressure of the airflow in the underground region 100d can be suppressed, and the static pressure of the underground region 100d can be measured.

[0044] In addition, such as Figure 2 As shown, the pad 15 is preferably provided along the edge 14a of the cup-shaped member 14. This reduces the intrusion of airflow from the above-ground area 100c into the space between the cup-shaped member 14 and the grid floor 102, thus making the space closer to the environment of the underground area 100d.

[0045] The cup-shaped component 14 can be made of a material with sufficient strength that does not affect the differential pressure measurement, and can be made of resin such as polypropylene or lightweight metal such as aluminum.

[0046] Furthermore, regarding the dimensions of the cup-shaped member 14, considering that the dimensions of the grid floor 102 are often around 600mm in length and 600mm in width, it is preferable that both the length and width are 100mm or more and 600mm or less. As long as both the length and width are 100mm or more, the static pressure of the underground area 100d can be obtained smoothly. Furthermore, as long as both the length and width are 600mm or less, the pressure difference can be precisely measured at different locations on a single grid floor 102. The most preferred dimensions for the cup-shaped member 14 are 200mm in length and 100mm in width. Sometimes, the pressure difference decreases with distance from the underground area 100d towards the return port 103; therefore, by setting the lateral length of the cup-shaped member to 100mm and arranging the lateral (short side) of the cup-shaped member 14 parallel to the direction of the return port 103 (see reference...),... Figure 4This allows for the confirmation of a finer differential pressure distribution. On the other hand, the longitudinal length of the cup-shaped member 14 is set to 200 mm, and the longitudinal (long side) of the cup-shaped member 14 is arranged perpendicularly to the direction of the return port 103 (see reference). Figure 4 This design allows for the expansion of the cup-shaped member 14's area in directions with minimal changes in distance, thereby increasing the stable measurement area and stabilizing the measurement value. Furthermore, the height of the cup-shaped member 14 is preferably 20 mm or more and 100 mm or less. When the height of the cup-shaped member 14 is 20 mm or more, a space simulating an underground region 100d can be formed inside the cup-shaped member, and the static pressure of the underground region 100d can be measured stably. Furthermore, when the height of the cup-shaped member 14 is 100 mm or less, the static pressure of the underground region 100d can be measured without compromising portability.

[0047] In the differential pressure measuring device 1 with the above-described structure, it is important that the distance in the device height direction between the other end 12b of the first pipe 12 and the other end 13b of the second pipe 13 is fixed. This allows for more accurate differential pressure measurement. Furthermore, "distance in the device height direction between the other end 13b of the second pipe 13" refers to the difference between the height position of the central axis of the first pipe 12 at its other end 12b and the height position of the central axis of the second pipe 13 at its other end 13b when the cup-shaped member 14 is placed on a horizontal surface with its edge 14a in contact with the horizontal surface.

[0048] Furthermore, it is preferable to fix the other end 12b of the first pipe 12 connected to the first port 11a for obtaining the pressure of the above-ground region 100c and the other end 13b of the second pipe 13 connected to the second port 11b for obtaining the pressure of the underground region 100d on the differential pressure measuring device 1 of the present invention.

[0049] The distance in the height direction between the other end 12b of the first pipe 12 and the other end 13b of the second pipe 13 is preferably 0 mm or more and 250 mm or less. This allows the pressure difference measurement error to be set to 0.1 Pa or less. More preferably, the distance in the height direction is 0 mm or more and 120 mm or less. This allows the pressure difference measurement error to be set to 0.0 Pa.

[0050] And, as Figure 2 As shown, the other end 12b of the first pipe 12 preferably faces a direction intersecting the height direction of the device. As described above, in order to adjust the airflow of clean air, it is necessary to measure the pressure difference between the static pressure of the above-ground region 100c and the static pressure of the underground region 100d. However, by having the other end 12b of the first pipe 12 facing a direction intersecting the height direction of the device, when obtaining the pressure of the above-ground region 100c, it is less susceptible to the influence of dynamic pressure compared to obtaining the pressure of the underground region 100d.

[0051] However, when the other end 12b of the first pipe 12 is oriented vertically upward, clean air enters the interior of the first pipe 12 and is greatly affected by dynamic pressure. Furthermore, when the other end 12b of the first pipe 12 is oriented vertically downward, the airflow reflected from the front of the cup-shaped member 14 easily enters the first pipe 12, and the influence of dynamic pressure becomes greater.

[0052] Therefore, the other end 12b of the first pipe 12 preferably faces a direction intersecting the height direction of the device. For example... Figure 2 As shown, the other end 12b of the first pipe 12 is preferably oriented in a direction orthogonal to the height direction of the device.

[0053] More preferably, it also has a cover that suppresses airflow to the other end 12b of the first pipe 12. There are no particular limitations on such a cover, as long as it is breathable and can reduce the momentum of the airflow and thus reduce dynamic pressure. The cover can be made of, for example, a porous material with a large number of bubbles, an aerator for supplying air in a water tank, a high-density cotton-like material, a metal material with small through holes (e.g., 0.05–1 mm in diameter), or resin spheres. Such a cover can be positioned above the other end 12b of the first pipe 12, or the aforementioned metal material can be made into a box shape and the other end 12b of the first pipe 12 can be inserted into the box-shaped cover, or the differential pressure measuring device 1 can be entirely housed within the box-shaped cover. Furthermore, the box-shaped cover can be a structure formed by stacking boxes of different sizes into two or three layers, or the other end 12b of the first pipe 12 or the differential pressure measuring device 1 can be positioned inside the innermost box-shaped cover.

[0054] Thus, using the differential pressure measuring device 1 based on the present invention, the differential pressure can be accurately measured even when the pressure difference between the ground area 100c and the underground area 100d is small. Furthermore, according to the present invention, the differential pressure measuring device 1 has excellent portability, and therefore can measure the pressure difference between the ground area 100c and the underground area 100d at various locations within the cleanroom 100.

[0055] (Differential pressure measurement method)

[0056] Next, the differential pressure measurement method based on the present invention will be described. The differential pressure measurement method based on the present invention is characterized in that the aforementioned differential pressure measuring device based on the present invention is disposed on the grid floor of a room with a grid floor, and the pressure difference between the pressure in the above-ground area and the pressure in the underground area is measured.

[0057] As described above, using the differential pressure measuring device 1 based on the present invention, the pressure of the underground region 100d can be measured in a state where the influence of dynamic pressure is reduced in the simulated underground region 100d space between the cup-shaped member 14 and the grid floor 102. Therefore, even when the pressure difference between the pressure in the above-ground region 100c and the pressure in the underground region 100d is small, the pressure difference between the pressure in the above-ground region 100c and the pressure in the underground region 100d can be measured accurately.

[0058] When the differential pressure measuring device 1 based on the present invention is disposed on the grid floor 102, the edge portion 14a of the cup-shaped member 14 is preferably disposed as far away as possible from the opening portion 102a of the grid floor 102, and preferably not disposed at all from the opening portion 102a. This allows the space between the cup-shaped member 14 and the grid floor 102 to more closely approximate the actual space of the underground area 100d.

[0059] Example

[0060] The present invention is described below with reference to embodiments thereof, but the present invention is not limited to the embodiments thereof.

[0061] As Figure 2 The differential pressure measuring unit 11 shown uses a differential pressure gauge (SIBATA SCIENTIFIC TECHNOLOGY LTD. FP-1 type) to investigate the effect of the difference in height between the first port 11a and the second port 11b on the differential pressure. Specifically, the first pipe 12 is not connected to the first port 11a, while one end 13a of the second pipe 13 is connected to the second port 11b. Furthermore, the differential pressure was measured with the other end 13b of the second pipe 13 at a height 0 mm (Reference Example 1), 250 mm (Reference Example 2), and 500 mm (Reference Example 3) lower than the height of the first port 11a. The above differential pressure measurements were performed with the first port 11a and the other end 13b of the second pipe 13 positioned in the ground area 100c. The resulting differential pressure values ​​were 0 Pa (Reference Example 1), 0.1 Pa (Reference Example 2), and 0.2 Pa (Reference Example 3). The results show that when the height difference between the first port 11a (i.e., the other end 12b of the first pipe 12) and the other end 13b of the second pipe 13 is 0 mm or more and 250 mm or less, the pressure difference can be measured with a measurement error of 0.1 Pa. When the difference is 0 mm or more and 120 mm or less, the pressure difference can be measured with a measurement error of 0.0 Pa.

[0062] (Example of an invention)

[0063] use Figure 2The differential pressure measuring device 1 shown measures the pressure difference between the surface area 100c and the underground area 100d within the cleanroom 100. Specifically, a differential pressure gauge (SIBATA SCIENTIFIC TECHNOLOGY LTD. FP-1 type) is used as the differential pressure measuring unit 11. Furthermore, the first piping 12 and the second piping 13 are made of silicone tubing, and the cup-shaped component 14 is made of polypropylene plastic. The cup-shaped component 14 has dimensions of 150 mm in length, 200 mm in width, and 50 mm in height.

[0064] like Figure 4 The pressure difference between the above-ground region 100c and the underground region 100d was measured by changing the distance between the differential pressure measuring device 1 and the return port 103. The results are shown in... Figure 5 .

[0065] (Comparative Example)

[0066] Similar to the invention example, the pressure difference between the pressure in the above-ground region 100c and the pressure in the underground region 100d was measured. However, as the pressure difference measuring device, [the following was taken out]. Figure 2 The differential pressure measuring device 1 shown has a differential pressure measuring section 11 used when the first pipe 12 is not connected to the first port 11a, and the second pipe 13 (500 mm in length) is connected to the second port 11b. During measurement, the other end 13b of the second pipe 13 is inserted into the underground area 100d through the opening 102a of the grid floor 102. All other conditions are the same as in the invention example.

[0067] Figure 5 This illustrates the relationship between the measurement location of the pressure difference and the measured pressure difference in both the inventive and comparative examples. Figure 5 It is clear that, in the inventive example, the pressure difference decreases as the measurement location moves away from the return port. In contrast, in the comparative example, when the other end 13b of the second pipe 13 is 65 to 105 cm from the return port 103, the pressure difference is constant, making it impossible to measure the pressure difference correctly.

[0068] Industrial availability

[0069] According to the present invention, even when the pressure difference between the pressure in the above-ground area and the pressure in the underground area is small, the pressure difference can be accurately measured, and therefore it is useful in the semiconductor industry.

[0070] Explanation of reference numerals in the attached figures

[0071] 1-Differential pressure measuring device, 11-Differential pressure measuring section, 12-First piping, 12a-One end of the first piping, 12b-The other end of the first piping, 13-Second piping, 13a-One end of the second piping, 13b-The other end of the second piping, 14-Cup-shaped component, 14a-Edge section, 15-Pad, 100-Cleanroom, 100a-Ceiling section, 100b-Ground, 100c-Above-ground area, 100d-Underground area, 101-Clean air supply section, 102-Grid floor, 102a-Opening section, 103-Return port, 104-Blower fan.

Claims

1. A differential pressure measuring device, characterized in that it measures the pressure difference between the above-ground area and the underground area of ​​a room with a grid floor, and is characterized in that... have: The differential pressure measuring unit has a first port for obtaining the pressure of the above-ground area and a second port for obtaining the pressure of the underground area, and one end of the first pipe is connected to the first port and one end of the second pipe is connected to the second port. and A cup-shaped component, connected to the other end of the second pipe, when disposed on the grating floor, forms a space between itself and the grating floor for measuring the pressure in the underground area. The distance in the height direction between the other end of the first pipe and the other end of the second pipe is fixed. The aforementioned cup-shaped member has a short side and a long side at its edge, and a pad is provided along the aforementioned edge.

2. The differential pressure measuring device according to claim 1, wherein, The distance in the height direction of the device between the other end of the first pipe and the other end of the second pipe is more than 0 mm and less than 250 mm.

3. The differential pressure measuring device according to claim 1 or 2, wherein, The other end of the first pipe is oriented in a direction that intersects with the height direction of the device.

4. The differential pressure measuring device according to claim 1 or 2, further comprising a cap that inhibits airflow to the other end of the first piping.

5. The differential pressure measuring device according to claim 3, further comprising a cap that inhibits airflow to the other end of the first piping.

6. A differential pressure measurement method, characterized in that, The differential pressure measuring device according to any one of claims 1 to 5 is arranged on the grid floor of a room with a grid floor on the ground, with the short side of the aforementioned cup-shaped member parallel to the return port and the long side of the aforementioned cup-shaped member perpendicular to the return port, and measures the differential pressure between the pressure in the ground area and the pressure in the underground area.

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