JP4673807B2 - Hydrostatic non-contact gas seal - Google Patents

Description

  The present invention provides a rotary seal ring on the rotary side member of the rotary device, and holds the static seal ring in the seal case attached to the static side member of the rotary device so as to be movable in the axial direction facing the rotary seal ring, The stationary seal ring is formed by machining to form a seal ring side passage that penetrates from the outer peripheral surface to the seal end face that is the opposite end face of the rotary seal ring, and the seal end face that is the opposite end face of both seal rings from this seal ring side passage The present invention relates to a static pressure type non-contact gas seal configured to keep a space between the sealed end faces in a non-contact state by supplying a seal gas therebetween.

As this type of static pressure type non-contact gas seal, as shown in FIG. 6 , a cylindrical seal case 109 attached to a stationary side member (equipment housing) of a rotating device, and a rotating side member (rotating shaft) of the rotating device. Rotating seal ring 108 fixed to 105, stationary seal ring 110 held in seal case 109 so as to be movable in the axial direction facing rotary seal ring 108, and stationary seal ring 110 pressed against rotary seal ring 109. A sealing end surface 112, which is an opposing end surface of both sealing rings 108, 110 from the sealing gas passage 111, and includes a spring member 146 that urges and a series of sealing gas passages 111 that penetrate the seal case 109 and the stationary sealing ring 110. A structure in which the sealing gas G is supplied between the sealing end surfaces 112 and 113 in a non-contact state by supplying a sealing gas G (hereinafter referred to as “ That come seal ") is well known (e.g., see FIG. 1 of Patent Document 1).

In the conventional seal, the seal gas passage 111 is an annular space formed between the opposed peripheral surfaces of the seal case 109 and the stationary seal ring 110 as shown in FIG. The connection space 133 closed by the first and second O-rings 121 and 122 loaded between the peripheral surfaces, the case side passage 135 formed in the seal case 109 and opened to the connection space 133, and the stationary seal ring 110 The static pressure generating groove 136 formed on the sealing end surface 113 and the sealing ring side passage 137 formed in the stationary sealing ring 110 and connecting the connection space 133 and the static pressure generating groove 136 to each other are formed. An opening force (static pressure) is generated between the sealing end surfaces 112 and 113 by the sealing gas G introduced into the sealing end surfaces 112 and 113, and the opening force and the sealing end surfaces 112 and 113 are closed. And balanced and closing force (spring load) of the spring member 146 acting on the direction, the seal end faces 112 and 113 is being held in a non-contact state.

  Thus, according to the conventional seal, the seal gas G is ejected from between the sealed end faces 112 and 113 to the sealed fluid region A and the non-sealed fluid region B, so that the regions A and B are completely shielded. Therefore, a good sealing function is exhibited even in a rotating device (for example, a rotating device in a semiconductor manufacturing apparatus, a pharmaceutical-related device, etc.) that requires a high degree of cleanness in the sealed fluid region A.

JP-A-4-224373

  By the way, the stationary seal ring 110 has a complicated shape as compared with the rotary seal ring 108, such as the formation of a seal ring side passage 137. Therefore, the stationary seal ring 110 is generally made of carbon in consideration of ease of processing. However, since the sealing ring side passage 137 is formed by machining such as drilling, the conventional seal should be suitably used as a sealing means for rotating equipment that requires a high degree of cleanliness. There was a problem that could not.

The sealing ring side passage 137 is a hole that penetrates from the outer peripheral surface of the stationary sealing ring 110 to the sealing end surface 113. Such a through hole is generally formed as follows by drilling. That is, as shown in FIG. 7 , the first drill hole 137a is formed in a direction orthogonal to the axis from an appropriate location (location facing the connection space 133) on the outer peripheral surface of the stationary seal ring 110, and the stationary seal ring 110 is sealed. A second drill hole 137b is formed in a direction along the axis from an appropriate position on the end surface 113 (where the static pressure generating groove 136 is formed), and both the drill holes 137a and 137b are joined.

However, the sealing ring side passage 137 formed by joining the drill holes 137a and 137b has a shape in which the end portions of both the drill holes 137a and 137b smoothly join as shown in FIG. Instead, at the joining portion 137c, the terminal portion 137d of at least one drill hole 137a protrudes from the joining portion 137c. Moreover, the sealed ring side passage 137 is not a smooth series of through-holes, but is bent at an intermediate portion thereof (a joining portion 137c of both the drill holes 137a and 137b). The generated seal gas G does not flow smoothly through the sealed-ring-side passage 137 and generates turbulent flow. On the other hand, the inner surface of each drill hole 137a, 137b is not a smooth surface but a rough surface having fine fluff due to its processing.

  Therefore, when a turbulent flow is generated in the merging portion 137c by the seal gas G passing at a high pressure and a high speed, particles (carbon powder) are generated from the inner surface and are accompanied by the seal gas G to the sealed fluid region A. There is a risk of intrusion.

  In general, the sealed-ring side passage 137 is cleaned by compressed air or the like after the processing, but there is a possibility that the processing waste is retained in the protruding portion 137d. There is also a risk of accompanying and entering the sealed fluid region A.

  The present invention has been made in view of such points, and even when the sealed ring side passage is formed by machining such as drilling, the sealing gas smoothly flows through the sealed ring side passage. Hydrostatic non-pressure that can effectively be used as a sealing means for rotating equipment that requires a high degree of cleanliness by effectively preventing generation of particles from the inner surface of the passage due to contact with the sealing gas. The object is to provide a contact gas seal.

The present invention is provided between a rotary table and a plastic cylindrical cover body that covers a drive unit thereof, and is a static seal that shields and seals between a processing area where the rotary table is disposed and an area in the cover body. A pressure-type non-contact gas seal comprising a rotary sealing ring fixed to a rotary table concentrically with the axis of rotation thereof, and a cylindrical metal made in a cover body and attached to a support machine frame of the drive unit A stationary case made of carbon that is concentric with the rotary seal ring and is held so as to be axially movable via the first and second O-rings on the inner periphery of the seal case in a state of being directly opposite to the seal case. A seal gas supply comprising a seal ring, a series of seal gas passages that pass through the seal case and the stationary seal ring, and a seal gas supply passage that penetrates the cover body in the axial direction thereof and communicates with the seal gas passage. Sealing said by supplying a high-pressure seal gas from both regions in the gas passage, a non-contact state between the seal end faces while ejecting a seal gas from between the sealing end faces are opposite end faces of the two seal rings in the two regions from A static pressure type non-contact gas seal configured to be held by the seal gas passage, wherein the seal gas passage is an annular space formed between opposing circumferential surfaces of the seal case and the stationary seal ring, and the first and second A connection space sealed by an O-ring, a case-side passage formed in a seal case and communicating with the connection space, a static pressure generating groove formed in a stationary sealing end surface which is a sealing end surface of the stationary sealing ring, and a stationary sealing ring This is a seal ring side passage formed by machining (drill drilling etc.), and connects the connection space and the static pressure generating groove through the outer peripheral surface of the static seal ring to the static seal end surface. Consists of a seal ring-side passage, with a seal ring-side passage axis of its is assumed that rectilinear no bent portion, at least the intermediate portion of the seal ring side passage, and the inner peripheral surface smooth and seal gas The present invention proposes a static pressure type non-contact gas seal characterized in that pipes that do not generate particles due to contact are closely inserted and fixed .

In the consuming hydrostatic noncontact gas seal, in order to prevent generation of particles from the inner surface of the seal ring side passage more effectively, at least the intermediate portion of the seal ring side passage, the inner peripheral surface smooth and seal resin which does not generate particles by contact with a gas, preferably a convenient way of挿固wearing tightly fitting the pipe metal and the like. In a preferred embodiment, the downstream end of the seal ring side passage is opened to a static pressure generating groove formed on the seal end surface of the static seal ring. In addition, an annular space formed between the inner peripheral surface of the seal case and the outer peripheral surface of the stationary sealing ring, and a connection space closed by the first and second O-rings loaded between the inner and outer peripheral surfaces. The upstream end of the seal ring side passage and the downstream end of the case side passage formed in the seal case are communicated so that the seal gas is supplied from the case side passage to the seal ring side passage through the connection space. The first sealing ring-side sealing surface that contacts the first O-ring on the outer peripheral surface of the sealing ring, and the second sealing ring-side sealing surface that contacts the second O-ring positioned on the rotating sealing ring side, and both sealing ring sides A frustoconical seal gas introduction surface located between the seal surfaces and orthogonal to the axis of the seal ring side passage is formed, and an upstream end of the seal ring side passage is opened on the seal gas introduction surface. It is preferable. In this case, the first sealing ring-side sealing surface is made smaller in diameter than the second sealing ring-side sealing surface, and a thrust force that presses the stationary sealing ring to the rotating sealing ring is generated by the sealing gas pressure acting on the connection space. I can keep it.

Moreover, although the said static pressure type non-contact gas seal is used as a sealing means of the rotary apparatus which has a rotary table, a rotary sealing ring can also be comprised by a part of the said rotary table.

  In the above-described operation method of the static pressure type non-contact gas seal, the rotation of the rotary table is started after the sealed end surfaces are held in a predetermined non-contact state by the seal gas introduced thereto. It is preferable that the supply of the sealing gas between the sealing end surfaces is stopped after the rotation of the rotary table is completely stopped.

  In the static pressure type non-contact gas seal of the present invention, the sealing ring side passage formed in the stationary sealing ring by machining such as drilling or the like has a straight shape without a bent portion, Thus, since there is no portion (bent portion or protruding portion) in which a turbulent flow due to the seal gas occurs in the sealed ring side passage, the seal gas can smoothly flow through the sealed ring side passage, Generation of particles from the inner surface (particle generation of carbon powder or the like due to contact with seal gas) can be prevented as much as possible. Therefore, according to the hydrostatic non-contact gas seal of the present invention, a good sealing function can be exhibited even in a rotating device that requires a high degree of cleanliness.

  Further, since the sealed ring side passage has a linear shape as described above, a pipe made of resin or the like is closely inserted into at least the middle portion, and the inside of this pipe is part or all of the sealed ring side passage. can do. Therefore, by forming at least the middle part of the seal ring side passage with the pipe in this way, generation of particles (carbon powder or the like) from the inner surface of the seal ring side passage can be more effectively prevented.

  FIG. 1 is a longitudinal side view showing an example of a rotating device equipped with a static pressure type non-contact gas seal according to the present invention, FIG. 2 is a detailed view showing an enlarged main part of FIG. 1, and FIG. It is a front view of the stationary sealing ring in the said static pressure type non-contact gas seal.

  The rotating device shown in FIG. 1 uses the rotary table 1 to perform appropriate processing (for example, cleaning processing, chemical processing, etc.) on a substrate (semiconductor wafer, electronic device substrate, liquid crystal substrate, photomask, glass substrate, etc.). A rotating table type processing apparatus for applying the processing table A, in which a high degree of cleanness is required for the processing area A in which the rotating table 1 is arranged, and the stationary covering the rotating table 1 as a rotating side member and its driving unit 2 By means of a static pressure non-contact gas seal 4 interposed between the plastic cylindrical cover body 3 as a side member, the processing area A and the area within the cover body 3 (the atmospheric area, hereinafter referred to as “inside cover area”). It is configured so as to provide a shielding seal with B. The drive unit 2 is connected to the rotary table 1 and extends in the vertical direction, a bearing that rotatably supports the rotary shaft 5, a drive means for the rotary shaft 5, and supports these in the cover inner region B. A support machine frame 6 is provided, and the rotary table 1 is driven to rotate. The turntable 1 is made of ceramics (silicon carbide in this example), and has a rotating body shape such as a disk disposed horizontally in the processing region A. Further, as shown in FIG. 1, the cover body 3 has a cylindrical shape with an upper end opening formed integrally with a chemical-resistant plastic (in this example, PTFE (polytetrafluoroethylene)). The drive part 2 arrange | positioned at the side is covered. As shown in FIG. 1, an appropriate labyrinth seal 7 may be provided between the back surface portion (lower surface portion) of the turntable 1 and the upper end portion (opening end portion) of the cover body 3 as necessary. it can. By providing such a labyrinth seal 7, in combination with a later-described action of a seal gas G ejected from the labyrinth seal 7 to the processing area A, intrusion of a chemical solution or the like from the processing area A into the in-cover area B Can be effectively prevented.

  As shown in FIG. 1, the static pressure type non-contact gas seal 4 includes a rotary seal ring 8 fixed to the rotary table 1 concentrically with the rotary axis thereof, and a support machine for the drive unit 2 disposed in the cover body 3. A cylindrical seal case 9 attached to the frame 6 and a stationary seal ring 10 which is concentric with the rotary seal ring 8 and is directly opposed to the inner periphery of the seal case 9 so as to be movable in the axial direction. The seal gas G is supplied from a series of seal gas passages 11 penetrating the seal case 9 and the stationary seal ring 10 to the sealed end surfaces 12 and 13 which are opposite end surfaces of both the seal rings 8 and 10, thereby An opening force generating means 14 that generates an opening force that acts in a direction to open the space between the sealing end surfaces 12 and 13 and a closing force that generates a closing force that acts on the stationary sealing ring 10 in a direction that closes the space between the sealing end surfaces 12 and 13. Generating means 15 , By balancing the this opening force and closing force, while retaining between seal end faces 12 and 13 in a non-contact state, the two regions A, and between B and is configured to shield the seal.

  The rotary seal ring 8 is an annular body formed of a material (for example, silicon carbide) harder than a constituent material (carbon) of the stationary seal ring 10 described later, and is fixed to the lower surface portion of the rotary table 1. . In this example, as shown in FIG. 1, an annular bulging portion that is concentric with the rotation axis is integrally formed on the lower surface portion of the turntable 1 made of silicon carbide, and this annular bulging portion is configured as a rotary sealing ring 8. It is. A lower end surface of the rotary seal ring 8 is a sealed end surface (hereinafter also referred to as “rotary seal end surface”) 12 which is a smooth annular surface.

  As shown in FIG. 1, the seal case 9 is a metal cylindrical structure including a seal case main body 16 and a seal flange 17 connected and integrated at a lower end portion thereof. In this example, the seal case body 16 is made of stainless steel (SUS304), and the seal flange 17 is made of an aluminum alloy. The seal case 9 has its lower end portion (lower end portion of the seal flange 17) 18 abutted against an annular cover step portion 19 formed on the inner peripheral portion of the cover body 3, and its outer peripheral portion (the outer peripheral portion of the seal case main body 16). ) In close contact with the inner peripheral portion on the upper end side of the cover body 3 (the inner peripheral portion on the upper side of the cover step portion 19) via the O-ring 20 made of fluoro rubber, via the seal flange 17 It is attached to the frame 6.

  As shown in FIG. 1, the stationary sealing ring 10 is a carbon annular body whose upper end surface is a sealing end surface (hereinafter also referred to as “stationary sealing end surface”) 13 which is a smooth annular surface, and a pair of parallel sealing in the vertical direction. The first and second O-rings 21 and 22 made of fluoro rubber are fitted and held on the inner peripheral portion of the seal case main body 16 so as to be movable in the axial direction (movable in the vertical direction). The outer diameter of the stationary sealing end face 13 is set slightly smaller than the outer diameter of the rotary sealing end face 12, and the inner diameter of the stationary sealing end face 13 is set slightly larger than the inner diameter of the rotary sealing end face 12. The lower first O-ring 21 is a first seal ring-side seal surface 23 that is an outer peripheral surface portion on the base end side (lower end side) of the stationary seal ring 10 and an inner peripheral surface portion of the seal case 9 that faces the first seal ring-side seal surface 23. The upper second O-ring 22 positioned between the case-side sealing surface 24 and on the rotary sealing ring side from the first O-ring 21 is an outer peripheral surface portion on the distal end side (upper end side) of the stationary sealing ring 10. Between the second seal ring side seal surface 25 and the second case side seal surface 26 which is the inner peripheral surface portion of the seal case 9 facing the second seal ring side seal surface 25, the seal case 9 and the stationary seal ring 10 are respectively mounted. Secondary sealing is performed between the opposing peripheral surfaces. The movement of both O-rings 21 and 22 in the proximity direction (the movement of the first O-ring 21 upward and the movement of the second sealing ring 22 downward) is located between both the sealing ring-side sealing surfaces 23 and 25. And is regulated by an annular protrusion (annular portion having a diameter larger than both seal ring side seal surfaces 23, 25) 27 formed on the outer peripheral portion of the stationary seal ring 10, and the O rings 21 and 22 move in the separation direction. (The movement of the first O-ring 21 downward and the movement of the second sealing ring 22 upward) are the first locking step 28 formed in the seal flange 17 and the second formed in the seal case body 16. It is regulated by the locking step 29. A circular hole 30 extending in the axial direction is formed at the base end (lower end) of the stationary seal ring 10, and a metal (for example, stainless steel such as SUS316) implanted in the seal flange 17 in the circular hole 30 is formed. By engaging the drive pin 31 (made of steel), the stationary seal ring 10 is allowed to rotate relative to the seal case 9 while allowing its axial movement in a predetermined range. The number of the circular holes 30 and the drive pins 31 engaged with the circular holes 30 is arbitrary, and a plurality of them are provided as necessary.

  As shown in FIG. 1, the opening force generating means 14 includes a series of seal gas passages 11 penetrating the seal case 9 and the stationary seal ring 10, a seal gas supply passage 32 formed in the cover body 3, and a seal gas supply passage. And a sealing gas supply device (not shown) for supplying the sealing gas G to the sealing gas passage 11 via 32.

  As shown in FIG. 1, the seal gas supply path 32 passes through the cover body 3 in the vertical direction (the axial direction of the cover body 3), and its upper end (downstream end) is opened to the cover step portion 19, The lower end (upstream end) is connected to an appropriate seal gas supply device.

  As shown in FIG. 1, the seal gas passage 11 includes a connection space 33 formed between the opposed peripheral surfaces of the seal case 9 and the stationary seal ring 10, and a case side formed in the seal case 9 and communicating with the connection space 33. Passages 34, 35, a static pressure generating groove 36 formed in the stationary sealing end face 13, and a sealing ring side passage 37 formed in the stationary sealing ring 10 to connect the connection space 33 and the static pressure generating groove 36 in communication. Consists of.

  The connection space 33 is an annular space formed between the opposed peripheral surfaces of the sealing ring holding portion 13 and the stationary sealing ring 10, and is sealed by the first and second O-rings 21 and 22.

  As shown in FIG. 1, the case-side passage includes a first case-side passage 34 that penetrates the seal flange 17 in the axial direction, and a second case-side passage 35 that penetrates the seal case body 16 from its lower end portion to its inner peripheral portion. It consists of. The upper end (downstream end) of the first case side passage 34 and the lower end (downstream end) of the second case side passage 35 are a fluororubber O-ring 38 interposed between the seal case body 16 and the seal flange 17. In a sealed state, the communication connection is established. An upper end (downstream end) of the second case side passage 35 is opened to the connection space 33. Further, the lower end (upstream end) of the first case side passage 34 is opened to the seal case end 18 directly opposite to the upper end opening (downstream end opening) of the seal gas supply path 32, and both paths 32. , 34 are connected in a state of being sealed with a fluororubber O-ring 39 interposed between the seal case end 18 and the cover step 19. A coating layer 40 made of a chemical resistant plastic such as PFA or PTFE is formed on the surface of the seal case 9.

  As shown in FIGS. 2 and 3, the static pressure generating groove 36 is a shallow concave groove that is formed in the central portion in the radial direction of the stationary sealed end surface 13 and forms a concentric ring with the sealed end surface 13.

  As shown in FIG. 2, the sealing ring side passage 37 is formed by machining the stationary sealing ring 10 such as drilling, and has a circular cross section in which the axis is a straight line having no bent portion. It is a drill hole, and penetrates the stationary sealing ring 10 linearly from the annular protrusion 27 of the stationary sealing ring 10 to the static pressure generating groove 36. In this example, as shown in FIG. 2, the side surface of the annular protrusion 27 on the first O-ring side is configured as a frustoconical seal gas introduction surface 38 orthogonal to the axis of the seal ring side passage 37 (sealing ring). The crossing angle α between the side passage 37 and the seal gas introduction surface 38 is 90 degrees), and the upstream end 42 of the seal ring side passage 37 is opened on the seal gas introduction surface 38, and the seal ring side passage A pipe 41 is closely fitted and fixed to an intermediate portion of 37.

  That is, the seal ring side passage 37 communicates between the upstream opening 42 formed in the seal gas introduction surface 38, the downstream opening 43 opened in the static pressure generating groove 36, and both the openings 42, 43. The pipe 41 is closely inserted into the intermediate part 44. The cross-sectional diameter of the intermediate portion 44 is set smaller than the cross-sectional diameter of the upstream opening 42 and larger than the cross-sectional diameter of the downstream opening 43, and the pipe 41 is inserted from the upstream opening 42 into the intermediate portion 44. It is designed to load densely. The inner diameter of the pipe 41 is set to be the same as the sectional diameter of the downstream opening 43. The pipe 41 has a smooth inner peripheral surface and does not generate particles due to contact with the seal gas G. A general metal tube or resin tube manufactured by drawing or the like is used as a sealing condition. It can be appropriately selected depending on the case. A pipe whose inner peripheral surface is a rough surface that may generate particles due to cutting or the like is not used. Further, for example, under a sealing condition in which the sealed fluid region A dislikes contamination by metal ions, a metal tube that may generate metal ions is not used, and a non-metallic resin tube or the like is used.

  Further, a restrictor 45 is disposed at an appropriate position of the sealing ring side passage 37. In this example, as shown in FIG. 2, a disc-shaped orifice 45 in which a minute through hole is formed in the central portion as compared with the inner diameter of the pipe 41 is fitted and fixed to the upstream opening 42. Removal of the pipe 41 from the sealed ring side passage 37 is prevented by the orifice 45.

  Thus, according to the opening force generating means 14, the seal gas G having a pressure P1 higher than the pressure P in the processing area A (and the pressure in the cover inner area B), which is a sealed fluid area, is supplied from the seal gas supply path 32 to the case side. By supplying the static pressure generating groove 36 through the passages 34 and 35, the connection space 33, the sealed ring side passage 37 and the orifice (throttle device) 45, that is, by supplying the seal gas G between the sealed end faces 12 and 13. The stationary seal ring 10 generates an opening force in a direction in which the stationary seal ring 10 is separated from the rotary seal ring 8, that is, in a direction in which the seal end faces 12 and 13 are opened. As the sealing gas G, a gas that is harmless even if it flows into the regions A and B and does not adversely affect the fluid to be sealed (fluid in the processing region A) is appropriately selected according to the sealing conditions. Select. In this example, clean nitrogen gas that is inert to various substances and harmless to the human body is used. Further, the pressure P1 of the sealing gas G is generally set or controlled to be higher by about 2.0 to 2.5 bar than the sealed fluid pressure P, although it depends on the sealing conditions.

  As shown in FIG. 2, the closing force generating means 15 sets the diameter D1 of the first seal ring side seal surface 23 to be smaller than the diameter D2 of the second seal ring side seal surface 25, so that the seal gas G acting on the connection space 33 A thrust force that presses the stationary seal ring 10 against the rotary seal ring 8, that is, a closing force, is generated by the pressure P1.

  In the static pressure type non-contact gas seal 4 configured as described above, when the seal gas G is supplied to the static pressure generating groove 36, the sealing end face 12 is sealed by the seal gas G introduced into the static pressure generating groove 36. , 13 generates an opening force that acts in the direction to open it. Further, the sealing gas G introduced into the connection space 33 acts on the stationary sealing ring 10 in a closing force that acts in the direction of closing the sealing end faces 12 and 13 and has a closing force that is in balance with the opening force. Therefore, the sealing end surfaces 12 and 13 are held in a non-contact state with an appropriate gap by the balance between the opening force and the closing force. That is, the sealing gas G introduced into the static pressure generating groove 36 forms a static pressure fluid film that balances with the closing force between the sealed end faces 12 and 13, and the presence and absence of this fluid film causes the inside and outside of the sealed end faces 12 and 13. The space between the radial regions A and B is sealed.

  Thus, since the pressure P1 of the sealing gas G is higher than the pressure P in the processing area A and the pressure in the cover inner area B, the sealing gas G is ejected from both the sealed end faces 12 and 13 to both areas A and B. And since the sealing ring side passage 37 formed in the stationary sealing ring 10 made of carbon has a linear shape, this differs from the case where it has a bent portion 137c and a protruding portion 137d (see FIG. 9). Since the seal gas G smoothly flows through the sealed ring side passage 37 without causing turbulence, the inner surface of the seal ring side passage 37 and the seal gas G are smoothly contacted. Part is peeled off and particles (carbon powder) are hardly generated. In particular, as shown in FIG. 2, when the pipe 41 is inserted into the intermediate portion 44 where particles are likely to be generated, the generation of particles due to contact with the seal gas G is extremely effectively prevented.

  Therefore, between the sealing end faces 12 and 13, clean sealing gas G not accompanied by particles will be ejected to both areas A and B, and even when a high degree of cleanness is required for the processing area A, This requirement can be fully met. Further, if the upstream end 39 of the seal ring side passage 37 is opened to the seal gas introduction surface 38 orthogonal to the axis thereof, the seal gas is smoothly introduced from the connection space 33 to the seal ring side passage 37, Further smoothing of the flow of the seal gas in the seal ring side passage 37 is realized, and formation of a static pressure fluid film by the seal gas G and prevention of particle generation due to contact with the seal gas G are more effectively performed. .

  By the way, when the rotary seal ring 8 is integrally formed with the rotary table 1 as described above, there is no need for a means for fixing the rotary seal ring 8 to the rotary table 1 and the configuration of the processing apparatus can be simplified. However, there is a demerit that the entire rotary table 1 needs to be replaced when the rotary sealing ring 8 that is only a part of the rotary table 1 is damaged or broken. However, such a demerit can be avoided by operating the static pressure type non-contact gas seal 4 as follows.

  That is, the rotation of the turntable 1 is started after the sealed end surfaces 12 and 13 are held in a predetermined non-contact state by the seal gas G introduced into the rotary table 1 and moved between the sealed end surfaces 12 and 13 of the seal gas G. Is stopped after the rotation of the turntable 1 is completely stopped. In this way, the sealing end surfaces 12 and 13 do not accidentally collide and are damaged or broken, and a smooth and good sealing function can be exhibited.

  The hydrostatic non-contact gas seal 4 according to the present invention is not limited to the above-described embodiment, and can be appropriately improved and modified without departing from the basic principle of the present invention. .

  For example, in the above-described example, the closing force generating means 15 is configured to generate the closing force by the sealing gas G, but it is also possible to configure so that part or all of the closing force is obtained by a spring load. For example, in the hydrostatic non-contact gas seal 4 shown in FIGS. 4 and 5, a spring member 46 is interposed between the stationary seal ring 10 and the seal case 9 (seal flange 17). A closing force acting in the direction of closing the sealed end faces 12 and 13 is generated. The configuration of the static pressure type non-contact gas seal 4 shown in FIGS. 4 and 5 is the same as that shown in FIGS. 1 to 3 except for the above points, and the same components are the same. The detailed description is omitted by attaching the reference numeral.

Further, in order to effectively prevent generation of particles (carbon powder or the like) due to contact with the seal gas G, the seal ring side passage 37 has the pipe 41 closely inserted into at least the intermediate portion 44 as described above. Although it is preferable to place, when interpolating fitting the pipes 41, using pipes that decorated a wringer, such as orifice 45, which also to keep was inserted into the entire seal ring side passage 37 Is possible.

It is a vertical front view which shows an example of the static pressure type non-contact gas seal which concerns on this invention. FIG. 2 is an enlarged detailed view showing a main part of FIG. 1. It is a partially cutaway plan view of a stationary sealing ring in the static pressure type non-contact gas seal. It is a longitudinal front view equivalent to FIG. 1 which shows the modification of the static pressure type non-contact gas seal concerning this invention. FIG. 5 is an enlarged detailed view showing a main part of FIG. 4. It is a vertical front view which shows a conventional seal | sticker . Is a detailed view showing an enlarged main portion of FIG.

Explanation of symbols

1 Rotary table (Rotating side member of rotating equipment)
DESCRIPTION OF SYMBOLS 2 Drive part of rotary table 3 Cover body 4 Static pressure type non-contact gas seal 6 Support machine frame of drive part 8 Rotating seal ring 9 Seal case 10 Static seal ring 11 Seal gas passage 12 Rotation seal end face (sealing end face of rotation seal ring )
13 stationary sealing end face (sealing end face of stationary sealing ring )
14 Opening force generating means 15 Closing force generating means 16 Seal case body 17 Seal flange 21 First O-ring 22 Second O-ring 23 First sealing ring-side sealing surface 25 Second sealing ring-side sealing surface 27 Annular protrusion 34 Case-side passage 35 Case side passage 36 Static pressure generating groove 37 Sealing ring side passage 38 Seal gas introduction surface 41 Pipe 42 Upstream side opening of sealing ring side passage 43 Downstream side opening of sealing ring side passage 44 Intermediate portion of sealing ring side passage A Processing area B Cover area (area inside the cover)
D1 Diameter of the first seal ring side seal surface D2 Diameter of the second seal ring side seal surface G Seal gas

Claims (4)

Hydrostatic non-contact that is interposed between the rotary table and a plastic cylindrical cover that covers the drive unit, and shields and seals between the processing area where the rotary table is placed and the area inside the cover. A gas seal,
A rotary seal ring fixed concentrically to the rotary table on the rotary table, a cylindrical metal seal case disposed in the cover body and attached to the support machine frame of the drive unit, and concentric with the rotary seal ring A stationary seal ring made of carbon, which is held in an axially movable manner through first and second O-rings on the inner peripheral portion of the seal case in a state of being directly opposed to the seal case, and the seal case and the stationary seal ring A series of seal gas passages penetrating through the cover body and a seal gas supply passage penetrating the cover body in the axial direction thereof and communicating with the seal gas passage. by supplying high-pressure seal gas, is configured to be held while ejecting a seal gas from between the sealing end faces are opposite end faces of the two seal rings in the two regions between the seal end faces in non-contact state A static pressure type non-contact gas seal,
A seal gas passage is an annular space formed between the opposed peripheral surfaces of the seal case and the stationary seal ring, and a connection space sealed by the first and second O-rings, and a connection space formed in the seal case. A static pressure generating groove formed in a stationary sealing end surface which is a sealing end surface of the stationary sealing ring, and a sealing annular side passage formed by machining in the stationary sealing ring, the stationary sealing ring And a sealing ring side passage that connects the connection space and the static pressure generating groove through the outer peripheral surface of the pierce to the stationary sealing end surface.
With a seal ring-side passage axis of its is assumed that rectilinear no bent portion, at least the intermediate portion of the seal ring side passage, the inner circumferential surface does not generate particles by contact with smooth seal gas pipe A static pressure non-contact gas seal characterized by being closely inserted and fixed. An annular space formed between the inner peripheral surface of the seal case and the outer peripheral surface of the stationary sealing ring, and sealed in the connection space closed by the first and second O-rings loaded between the inner and outer peripheral surfaces. The upstream end of the ring side passage and the downstream end of the case side passage formed in the seal case are connected to supply seal gas from the case side passage to the sealed ring side passage through the connection space. A first sealing ring-side sealing surface in contact with the first O-ring, a second sealing ring-side sealing surface in contact with a second O-ring positioned on the rotary sealing ring side, and both sealing ring-side sealing surfaces A frustoconical seal gas introduction surface that is located between and perpendicular to the axis of the seal ring side passage is formed, and the upstream end of the seal ring side passage is opened on the seal gas introduction surface. The hydrostatic non-contact according to claim 1, Gas seal. The first sealing ring-side sealing surface has a smaller diameter than the second sealing ring-side sealing surface, and is configured to generate a thrust that presses the stationary sealing ring to the rotating sealing ring by the sealing gas pressure acting on the connection space. to, static pressure type non-contact gas seal as described in 請 Motomeko 2. Rotary seal ring is characterized that you have been composed of a part of the rotary table, the static pressure type non-contact gas seal according to any one of claims 1 to 3.