Fixing structure for metal piping

Abstract

[Problem] To provide a fixing structure for fixing a metal pipe to a metal gas box while ensuring airtightness inside the gas box, wherein, a drop in the temperature of a process gas flowing through the metal pipe extending from the inside of the gas box to the outside is suppressed. [Solution] A fixing structure 1 for fixing a metal pipe 3 extending from the inside of a gas box 2 to the outside through an opening 2a provided in the gas box 2 comprises a plate-like member 6 which is fixed to an outer surface of the gas box 2 to close the opening 2a and has a portion through which the metal pipe 3 passes. The plate-like member 6 has a thermal conductivity lower than that of the metal pipe 3.

Description

Technical Field

[0001] The present invention relates to a fixing structure for metal pipes, and particularly to a structure for fixing a metal pipe extending from a gas box to the gas box.

Background Art

[0002] Conventionally, in semiconductor manufacturing equipment and the like, a gas supply system has been used to supply process gas to a process chamber. The gas supply system integrates flow controllers and valves provided in a plurality of gas supply lines and accommodates them in a gas box (Patent Document 1, etc.).

[0003] The gas box is used, for example, to prevent leakage to the surroundings and improve safety when a gas leak occurs. An exhaust path is connected to the gas box to prevent leaked gas from flowing out to the surroundings, and the gas box is sometimes filled with an inert gas such as nitrogen gas to prevent the leaked process gas from reacting with air.

[0004] In order to cope with leaked gas from the gas supply system, the gas box is required to have appropriate airtightness. The gas box is formed as a housing by welding metal plates such as aluminum, for example.

[0005] Further, a vaporizer may be accommodated in the gas box in some cases. The vaporizer generates high-temperature process gas by heating and vaporizing a liquid raw material. To prevent the high-temperature process gas from re-liquefying in the metal pipe before reaching the process chamber, a heater is attached along the metal pipe that transports the process gas, and the heater is further covered with a heat insulating material, thereby preventing a temperature drop of the process gas.

Prior Art Literature

Patent Literature

[0006]

Patent Document 1

[0007] As mentioned above, when handling high-temperature gases, metal piping is covered with heaters or insulation to prevent the temperature of the high-temperature gas from dropping.

[0008] However, despite this, the temperature of the gas passing through the metal pipe sometimes fell below the desired temperature.

[0009] Therefore, the primary objective of the present invention is to provide a metal piping fixing structure that can suppress the temperature drop of high-temperature process gas flowing through metal piping extending from a gas box. [Means for solving the problem]

[0010] To solve the above problems, the inventors conducted diligent research and found the factors causing a temperature drop in high-temperature process gases inside metal piping, as well as a means to resolve them.

[0011] As mentioned above, when handling high-temperature gases, it is possible to prevent a certain degree of temperature drop of the gas by covering the metal piping with heaters or insulation. However, it is necessary to fix the metal piping to the gas box to suppress gas leaks from the gas box and to prevent the metal piping from rattling due to shocks or vibrations. If metal piping is fixed to the gas box using fixing fittings such as flanged pipe fittings, it is not possible to install a heater on the metal piping at the fixed part.

[0012] Therefore, the heat from the high-temperature process gas passing through the metal piping escapes from the metal piping to the fixed point between the metal piping and the gas box. Furthermore, heat is transferred from that fixed point to the metal gas box and dissipated. As a result, the temperature of the process gas inside the metal piping decreases.

[0013] Therefore, the fixing structure for metal piping according to an embodiment of the present invention is a fixing structure for fixing metal piping extending from the inside to the outside of a gas box through an opening provided in the metal gas box, and comprises a plate-shaped member having a passage for the metal piping and fixed to the outer surface of the gas box to close the opening, wherein the plate-shaped member has a thermal conductivity lower than that of the metal piping.

[0014] The material of the plate-like member may be a super engineering plastic.

[0015] The material of the plate-like member may be polyetheretherketone.

[0016] The material of the plate-like member may be a synthetic resin having heat resistance of 150°C or higher.

[0017] The aforementioned metal piping may be covered with a heater.

[0018] The plate-shaped member may be made of synthetic resin, and a metal fitting portion that fits into the opening may be provided on the plate-shaped member.

[0019] A guide portion for guiding the fitting portion into the opening may be erected on the side edge of the fitting portion.

[0020] The fitting portion may be configured to surround the metal pipe with a predetermined gap between it and the metal pipe so as not to come into contact with the metal pipe. [Effects of the Invention]

[0021] According to the metal piping fixing structure of the embodiment of the present invention, it is possible to provide airtightness to the gas box, properly fix the metal piping extending from the gas box, suppress heat dissipation from the metal piping, and suppress the temperature drop of the high-temperature process gas flowing through the metal piping. [Brief explanation of the drawing]

[0022] [Figure 1]It is a cross-sectional view showing a fixing structure for a metal pipe according to an embodiment of the present invention. [Figure 2] It is an exploded perspective view showing the components of a fixing structure for a metal pipe according to an embodiment of the present invention. [Figure 3] It is a perspective view of a plate-shaped member, which is one of the components shown in Fig. 2, viewed from the back side. [Figure 4] It is a perspective view of a fitting portion, which is one of the components shown in Fig. 2, viewed from a direction different from that in Fig. 2. [Figure 5] It is a perspective view showing an example of an upper gas box that is a part of a gas box. [Figure 6] It is a perspective view showing an upper gas box incorporating the components, together with an exploded perspective view of the components of the metal pipe fixing structure of Fig. 2. MODE FOR CARRYING OUT THE INVENTION

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 6, but the present invention is not limited to the embodiments described below.

[0024] Fig. 1 shows a state where a metal pipe 3 is fixed to a gas box 2 by a metal pipe fixing structure 1 according to an embodiment of the present invention. A gas processing device 4 to be incorporated in a gas supply system is housed inside the gas box 2. The gas box 2 is made of metal, and is preferably formed of stainless steel. The metal pipe 3 is preferably formed of a stainless steel circular pipe having corrosion resistance to process gas. A joint 3a for connecting to another metal pipe or the like is provided at the tip end of the metal pipe 3.

[0025] The gas treatment device 4 may have various configurations. The gas treatment device 4 may include a flow control device and a vaporizer. However, it is not limited to this embodiment, and the gas treatment device 4 may be any gas supply line component where gas leakage may occur, such as metal piping, flow path blocks, and fluid elements (valves, etc.). Although not shown in the figures, wiring connected to the flow control device etc. housed in the gas box 2 is drawn out from the gas box 2.

[0026] Furthermore, the metal pipe 3 extending from the inside to the outside of the gas box 2 may be a raw material inlet pipe through which gaseous or liquid raw materials flow, a gas outlet pipe that delivers raw material gas (process gas) vaporized by the vaporizer, or a filling gas supply pipe that supplies filling gas to the gas box 2. Although only one metal pipe 3 is shown in Figure 1, multiple metal pipes may be provided. The metal pipe 3 through which the high-temperature gas vaporized by the vaporizer flows may be insulated by a heater 5 that covers the metal pipe 3.

[0027] The inside of the gas box 2 is typically supplied with an inert gas (in this case, nitrogen gas) from a filling gas supply pipe at a pressure equal to or greater than atmospheric pressure. This prevents the leaked gas from reacting with oxygen in the air, etc., even if gas leaks from the gas treatment device 4. To prevent ambient air from flowing into the gas box 2, it is desirable that the pressure of the inert gas inside the gas box 2 be maintained at or above the external pressure (typically atmospheric pressure).

[0028] The gas box 2 is provided with an opening 2a through which a metal pipe 3 passes. The metal pipe 3 extends from the inside to the outside of the gas box 2 through the opening 2a. A plate-shaped member 6 having a passage 6a (Figure 1) through which the metal pipe 3 passes is fixed to the outer surface of the gas box 2 so as to close the opening 2a.

[0029] The plate-shaped member 6 is positioned with its bottom surface facing the outer surface of the gas box 2 and is fixed to the gas box 2 by screws 7 (Figure 6). By fixing the plate-shaped member 6 to the gas box 2, the gap between the inner surface of the opening 2a and the outer surface of the metal pipe 3 is sealed.

[0030] As shown in Figure 2, the plate-shaped member 6 can be composed of a pair of first plate-shaped portions 6b and second plate-shaped portions 6c that are arranged to sandwich the outer circumferential surface of the metal pipe 3 from both sides. A groove portion 6e for forming a passage portion 6a for the metal pipe 3 is formed at the joint surface of the first plate-shaped portion 6b and the second plate-shaped portion 6c. By supporting the outer circumferential surface of the metal pipe 3 with the inner circumferential surface of the passage portion 6a, lateral movement and rattling of the metal pipe 3 are prevented. The plate-shaped member 6 can also be a single plate with a single hole that serves as a passage portion 6a for the metal pipe 3, rather than being a two-part type as shown in the example.

[0031] The gas box 2 shown in Figure 1 is separable into an upper gas box 2b and a lower gas box 2c. Figure 5 is an exploded perspective view of the upper gas box 2b, and Figure 6 is a perspective view showing an example configuration in which the fixing structure 1 is provided on the upper gas box 2b. The upper gas box 2b in the illustrated example is composed of a first part 2b1 and a second part 2b2. 1 part It is formed by arranging part 2b1 and the second part 2b2 adjacent to each other and joining them with high airtightness. In this specification, the terms "upper" and "lower" are used for explanatory purposes, but may differ from actual upper and lower parts.

[0032] An opening 2a is formed at the joint between the first part 2b1 and the second part 2b2. In the illustrated embodiment, recessed areas are provided at the joint edges of both the first part 2b1 and the second part 2b2. These recessed areas together form the opening 2a. Although not shown, recessed areas may be provided on only one of the first part 2b1 or the second part 2b2. In this example, a gas box divided into upper and lower sections is used to appropriately surround the metal pipe 3 that extends outward and bends from the gas processing device 4 as shown in Figure 1 after it is housed in the lower gas box 2c. However, a single-piece gas box with an opening 2a may be used as long as it is configured to allow the metal pipe 3 to pass through. The opening 2a of the gas box 2 is preferably rectangular, but may be of other shapes.

[0033] To further enhance airtightness, preferably, the plate-shaped member 6 has a stepped portion 6g (Figure 2) around the passage portion 6a on the side opposite to the gas box 2, and an annular sealing member 9 made of an elastic material is housed in the stepped portion 6g. A pressing member 10 that presses against the annular sealing member 9 can be fixed to the plate-shaped member 6. When the pressing member 10 presses against the annular sealing member 9 within the stepped portion 6g, the annular sealing member 9 elastically deforms within the stepped portion 6g and presses against the plate-shaped member 6 and the metal pipe 3, sealing the space between the plate-shaped member 6 and the metal pipe 3. The pressing member 10 can be made of a metal plate such as stainless steel with a thickness of about 1 to 2 mm.

[0034] The retaining member 10 is fixed to the plate-shaped member 6 by screws 11 (Figure 6). The retaining member 10 can be composed of a first retaining portion 10a and a second retaining portion 10b, which are arranged to sandwich the metal pipe 3 from both sides. Semicircular recesses 10a1 and 10b1 are formed at the joint edges of the first retaining portion 10a and the second retaining portion 10b to form a circular passage through which the metal pipe 3 passes. The retaining member 10 can also be composed of a single plate.

[0035] The joint between the first pressing portion 10a and the second pressing portion 10b is positioned to intersect with the joint between the first plate-like portion 6b and the second plate-like portion 6c. The first pressing portion 10a is fixed to the first plate-like portion 6b and the second plate-like portion 6c with screws 11. Similarly, the second pressing portion 10b is fixed to the first plate-like portion 6b and the second plate-like portion 6c with screws 11. As a result, the first pressing portion 10a, the second pressing portion 10b, the first plate-like portion 6b, and the second plate-like portion 6c are directly or indirectly connected to each other and become a single unit. Through holes 10c for passing screws 11 are formed in the first pressing portion 10a and the second pressing portion 10b, and screw holes 6f for screwing screws 11 are formed in the first plate-like portion 6b and the second plate-like portion 6c.

[0036] The plate-shaped member 6 preferably has a certain thickness, for example, 3 to 10 mm, in order to support the outer surface of the metal pipe 3 and suppress rattling of the metal pipe 3. On the other hand, the pressing member 10 only needs to be able to press and elastically deform the annular sealing member 9, and a metal plate that is thinner and smaller than the plate-shaped member 6 can be suitably used.

[0037] The plate-shaped member 6 is made of a material having a lower thermal conductivity than the metal pipe 3. This suppresses heat transfer from the metal pipe 3 to the plate-shaped member 6, thereby preventing a decrease in the temperature of the high-temperature process gas inside the metal pipe 3.

[0038] On the other hand, when handling high-temperature process gases, it is preferable that the plate-shaped member 6 has high heat resistance capable of withstanding the high temperature of the process gas. For this reason, a super engineering plastic, which is a high-performance resin with very high heat resistance and mechanical strength, is preferably used for the plate-shaped member 6.

[0039] Super engineering plastics are plastics that generally have heat resistance of 150°C or higher, making them suitable for generating high-temperature process gases using vaporizers. Known super engineering plastics include PPS (polyphenylene sulfide), PSU (polysulfone), PPSU (polyphenylene sulfone), PAR (polyarylate), PES (polyethersulfone), PEI (polyetherimide), PAI (polyamideimide), PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxyalkane polymer), PEEK (polyetheretherketone), PEK (polyetherketone), PEKK (polyetherketoneketone), and PI (polyimide).

[0040] Among super engineering plastics, PEEK (polyetheretherketone) is particularly preferred because its continuous operating temperature (also called continuous heat resistance temperature) is approximately 240°C to 250°C. Furthermore, the thermal conductivity of standard PEEK material (test method ASTM D177) is 0.25 W / (m·K), which is much lower than that of aluminum (236 W / (m·K)) and stainless steel (SUS304) (16 W / (m·K).

[0041] The material of the plate-shaped member 6 is not limited to thermoplastic resins such as super engineering plastics, but may also be thermosetting resins that have heat resistance to high temperatures (150 degrees Celsius or higher), such as epoxy resins or phenolic resins. These synthetic resin materials generally have lower thermal conductivity than metal materials. Ceramics can also be used as the material for the plate-shaped member 6.

[0042] A fitting portion 8 is provided on the bottom surface of the plate-shaped member 6 so as to protrude from the bottom surface of the plate-shaped member 6, and fits into the opening 2a. This fitting portion 8 can be formed to a size that is press-fitted into the opening 2a of the gas box 2.

[0043] When the plate-shaped member 6 is made of the resin material described above, it is desirable to use a metal material for the fitting portion 8 and to screw-fix the fitting portion 8 to the plate-shaped member 6. By constructing the fitting portion 8 with a metal material in this way, the gas box 2 Even if process gas leaks inside, the process gas will not come into contact with the plate-shaped member 6 made of resin material, thus preventing combustion.

[0044] The fitting portion 8 may comprise a pair of first fitting portions 8a and second fitting portions 8b that join to each other. The first fitting portion 8a is fixed to the first plate-shaped portion 6b, and the second fitting portion 8b is fixed to the second plate-shaped portion 6c. Recesses 8a1 and 8b1 for passing the metal pipe 3 are formed on each joining surface where the first fitting portion 8a and the second fitting portion 8b join. The fitting portion 8 may also be constructed as a single integrated part rather than being two separate parts, the first fitting portion 8a and the second fitting portion 8b.

[0045] When the fitting portion 8 is made of a metal material, the recesses 8a1 and 8b1 may be configured to surround the metal pipe 3 with a predetermined gap G (Figure 1) between the recesses 8a1 and 8b2 and the metal pipe 3 so as not to come into contact with the metal pipe 3. This prevents heat transfer from the metal pipe 3 to the fitting portion 8 and suppresses the temperature drop of the high-temperature gas flowing inside the metal pipe 3.

[0046] To position the fitting portion 8 with respect to the plate-shaped member 6, a positioning projection 6h (Figure 3) is formed on the bottom surface of the plate-shaped member 6 (first plate-shaped portion 6b, second plate-shaped portion 6c), and recesses 8a2 and 8b2 (Figure 2) into which the projection 6h fits may be formed in the first fitting portion 8a and the second fitting portion 8b, respectively. Alternatively, a recess may be formed in the plate-shaped member 6, and a projection that fits into the recess may be formed in the fitting portion 8.

[0047] Through holes 8a3 and 8b3 are formed in the recesses 8a2 and 8b2 through which the screw 12 (Figure 6) passes. On the other hand, a screw hole 6i (Figure 3) is formed in the protrusion 6h into which the screw 12 is screwed. By fitting the protrusion 6h into the recesses 8a2 and 8b2, the through holes 8a3 and 8b3 and the screw hole 6i align. By passing the screw 12 through the through holes 8a3 and 8b3 and screwing it into the screw hole 6i, the fitting portion 8 is fixed to the plate-shaped member 6.

[0048] The retaining member 10 and the plate-shaped member 6 are fixed together with a screw 11, and the plate-shaped member 6 and the fitting portion 8 are fixed together with a screw 12, thereby integrating the retaining member 10, the plate-shaped member 6, and the fitting portion 8. In this integrated state, the fitting portion 8 is fitted into the opening 2a of the gas box 2, thereby positioning the plate-shaped member 6 in a fixed position relative to the gas box 2. This positioning aligns the through hole 6d in the plate-shaped member 6 with the screw hole 2d (Figure 5) in the gas box 2, and the plate-shaped member 6 can be fixed to the outer surface of the gas box 2 by passing the screw 7 through the through hole 6d and screwing it into the screw hole 2d (Figure 5).

[0049] To facilitate the insertion of the fitting portion 8 into the opening 2a of the gas box 2, a guide portion 8a4 (Figure 4) can be provided on the side edge of the fitting portion 8. By making the guide portion 8a4 a plate that bends upright from the side edge of the plate-shaped fitting portion 8, the fitting portion 8 can be formed in an L-shape in cross-section. The guide portion 8a4 can be made easier to insert by providing a tapered portion 8a5 at the corner of the tip end that is inserted into the opening 2a. With this configuration, when inserting the fitting portion 8 into the opening 2a, the tapered portion 8a5 guides the guide portion 8a4 into the opening 2a, and then, by sliding the guide portion 8a4 while it is in contact with the edge of the opening 2a, the fitting portion 8 is guided by the guide portion 8a4 and inserted into the opening 2a, thereby fitting the fitting portion 8 into the opening 2a.

[0050] If the process gas flowing through the metal pipe 3 is a high-temperature gas, the metal pipe 3 can be covered with a heater 5 (Figure 1) to prevent a drop in the temperature of the process gas. The heater 5 may be a jacket heater or a tape heater, and may be installed inside and outside the gas box 2 to cover the metal pipe 3, except for the portion enclosed by the plate-shaped member 6. The heater 5 is temperature-controlled to a desired temperature (e.g., 40 to 200°C) by an external temperature controller.

[0051] A comparative test was conducted to measure the temperature change of gas passing through a metal pipe in an embodiment and a comparative example of the fixed structure according to the present invention. The embodiment used in the comparative test was the fixed structure shown in Figure 6, in which the plate-shaped member 6 was made of PEEK material and the metal pipe 3 was covered with a jacket heater. The comparative example used in the comparative test differed from the embodiment only in that the plate-shaped member was made of aluminum. The gas box, metal pipe, and retaining member were all made of stainless steel. With high-temperature gas (controlled to 130°C) generated in the vaporizer inside the gas box and flowing through the metal pipe, the temperature was measured outside the gas box 2 near the plate-shaped member (point A in Figure 1) using a thermocouple attached to the outer surface of the metal pipe 3. The result was 114.8°C in the comparative example, compared to 126.7°C in the embodiment. Therefore, by changing the material of the plate-shaped member from aluminum to PEEK material, the temperature drop of the high-temperature gas flowing through the metal pipe was considerably suppressed. This is because the amount of heat lost from the high-temperature gas to the plate-like member in contact with the metal pipe is greater in the comparative example than in the example. From this, it can be seen that by forming the plate-like member from a material with a lower thermal conductivity than the metal pipe, the temperature drop of the high-temperature gas flowing inside the metal pipe can be suppressed.

[0052] As is clear from the above description, the metal piping fixing structure according to the present invention makes the gas box airtight, and while appropriately fixing the metal piping extending from the gas box so that it does not rattle, it is possible to suppress heat dissipation from the metal piping and suppress the temperature drop of the high-temperature process gas flowing through the metal piping, thereby contributing to the prevention of reliquefaction of the high-temperature gas flowing through the metal piping.

[0053] The present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. For example, although the above embodiments show an example in which the plate-shaped member and the fitting portion are constructed as separate parts, it is also possible to make an integrally molded product in which the plate-shaped member and the fitting portion are formed integrally. [Explanation of Symbols]

[0054] 1 Fixed structure 2 Gas Box 3. Metal piping 4. Gas treatment equipment 5 Heater 6 Plate-shaped member 8. Fitting part 8a4 Information Department

Claims

1. A fixing structure for securing metal piping that extends from the inside to the outside of a metal gas box through an opening provided in the gas box, It has a passage for the metal piping and is equipped with a plate-shaped member that is fixed to the outer surface of the gas box and closes the opening, The plate-shaped member has a thermal conductivity lower than that of the metal pipe, and is a fixing structure for the metal pipe.

2. The metal piping fixing structure according to claim 1, wherein the material of the plate-shaped member is a super engineering plastic.

3. The metal piping fixing structure according to claim 2, wherein the material of the plate-shaped member is polyetheretherketone.

4. The metal piping fixing structure according to claim 1, wherein the material of the plate-shaped member is a synthetic resin having heat resistance of 150°C or higher.

5. The metal piping fixing structure according to claim 1, wherein the metal piping is covered with a heater.

6. The metal piping fixing structure according to claim 1, wherein the material of the plate-shaped member is synthetic resin, and a metal fitting portion that fits into the opening is provided on the plate-shaped member.

7. The metal piping fixing structure according to claim 6, wherein a guide portion for guiding the fitting portion into the opening is erected on the side edge of the fitting portion.

8. The metal pipe fixing structure according to claim 6, wherein the fitting portion is configured to surround the metal pipe with a predetermined gap between it and the metal pipe so as not to come into contact with the metal pipe.

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