JP4999547B2 - Joint structure - Google Patents

Description

  The present invention relates to a joint structure for connecting connection pipes.

  2. Description of the Related Art In semiconductor manufacturing apparatuses, general industrial machines, and the like, a pipe configuration including a connection pipe is used for transporting fluids such as air, pure water, cold or hot water for temperature adjustment, and organic chemicals. Such a pipe configuration includes a joint structure for connecting the connecting pipe to another member, for example, another connecting pipe or a fluid inlet / outlet of the apparatus housing.

  Conventionally, as a joint structure for connecting a pair of connecting pipes to each other, for example, there is a configuration in which end faces of the connecting pipes are held in close contact with each other. In that case, a rubber O-ring is sandwiched between both end faces in order to enhance confidentiality. A groove for holding the O-ring is formed on each end face. A flange may be formed on each end face of each connecting pipe.

  However, in recent years, for example, in semiconductor manufacturing equipment, especially in the gas supply section to the reaction chamber, it is possible to manufacture defective products that cannot be used simply by mixing impurities or changing the pressure or flow rate of the fluid. May end up. Therefore, the pipeline structure provided at such a position requires a much higher level of airtightness than before. As described above, in the configuration using the O-ring, it is difficult to realize exceptionally high airtightness due to the nature of the rubber that is the material of the O-ring, and the reliability is lowered due to the aging of the rubber. easy. Furthermore, there is no denying the possibility that the flowing gas and rubber will undergo a chemical reaction and deteriorate.

Therefore, Patent Document 1 and Patent Document 2 propose a configuration in which a ring-shaped metal gasket is sandwiched between end faces of a connection pipe (tubular joint member) instead of an O-ring. In these configurations, an annular seal bead (protrusion) is provided on each end face, and these seal beads are brought into contact with both faces of the gasket. In the configurations of Patent Documents 1 and 2, a connection nut having an internal thread portion that is screwed into an external thread portion on the outer periphery of one connection tube and an engagement portion that engages with the other connection tube is used. By deeply screwing the male threaded portion of the connecting nut into the female threaded portion of the connecting pipe, the gasket is strongly pressed from both sides by the seal beads on both end surfaces to achieve high airtightness.
Japanese Examined Patent Publication No. 2-62756 Japanese Patent No. 3517719

  In the configuration described in Patent Document 1, high airtightness is achieved by deeply screwing the male threaded portion of one of the connecting pipes into the female threaded portion of the coupling nut. The other connecting pipe may also rotate together. At that time, friction is generated between the sealing bead of the rotating connecting pipe and the gasket to which the sealing bead is pressed, and fine particles (particles) of the metal are generated and float. This fine particle becomes an impurity mixed in the flowing gas. Further, not only the generation of particles, but also the surface seal portion is damaged by the rotation of the connecting pipe, and it is easy to leak from there.

  Even if the fine particles are not generated at the completion of assembly of the joint, or even if the fine particles are removed immediately after the completion of the assembly and put into actual use, the fine particles are not removed during long-term use. May occur. That is, as described above, when the other connecting pipe rotates together with the rotation of the connecting nut, the tip end portion of the other connecting pipe may be held in a twisted state. In this case, when the connection pipe gradually moves in the direction to eliminate the twist due to the repulsive force of the connection pipe, or when the force for fixing the pair of connection pipes to each other is weakened by expansion or contraction due to temperature change, the connection pipe There is a possibility that the tube moves in a direction to eliminate the twist. As a result, friction is generated between the seal bead and the gasket, and fine metal particles may be generated and float. Further, in addition to the generation of such particles, the holding force is reduced due to the weakening of the force for fixing the pair of connecting pipes to each other, and leakage easily occurs.

  Thus, according to the configuration of Patent Document 1, although high airtightness to the outside of the joint structure can be obtained, fine metal particles are generated inside the joint structure and mixed into the fluid flowing through the joint structure. May be an impurity. In particular, when this joint structure is employed in a gas supply unit of a semiconductor manufacturing apparatus, it is impossible to manufacture a desired semiconductor because fine particles generated by friction between a seal bead and a metal gasket are mixed as impurities. It becomes a fatal problem.

  In the configuration described in Patent Document 2, a thrust ball bearing is disposed between the other connecting pipe (tubular joint member) and the engaging portion of the connecting nut. This thrust ball bearing can prevent the connecting nut and the other connecting pipe from rotating together. As a result, generation of metal fine particles (particles) can be suppressed, and the risk of leakage can be reduced. However, in this configuration, since the thrust ball bearing is used, the assembly process of the joint structure becomes complicated, and the manufacturing cost and the assembly time increase.

  In both Patent Documents 1 and 2, manufacturing is complicated because a male screw is formed on the outer periphery of one connecting pipe (tubular joint member). When the male threaded portion of one connecting pipe and the female threaded section of the connecting nut are screwed together, for example, two spanners or the like are used as tools to fix the other of the connecting pipe and the connecting nut while fixing the other. It is common to rotate. At this time, the space for handling a tool such as a spanner may not be sufficient to sufficiently tighten the male screw portion and the female screw portion. That is, in a state where the male threaded portion of one of the connecting pipes is screwed into the female threaded portion of the connecting nut to form the joint structure, there is not a very wide space around the joint structure, and various members constituting the pipe line, In many cases, there is a part of the casing of the apparatus. Further, there are cases where a multi-system pipe line configuration is provided in a semiconductor manufacturing apparatus or the like, and the above-described joint structure is included in each pipe line. In such a state, when the tightening of both screw parts is insufficient for some reason, it is necessary to further tighten using two spanners as described above, but the operator can freely operate a tool such as a spanner. Difficult to do. Specifically, in the case of the configurations of Patent Documents 1 and 2, for example, it is necessary to use two spanners, a spanner for holding one connecting pipe so as not to rotate and a spanner for rotating the connecting nut. Moreover, it is desirable to increase the span of the spanner during the operation in order to apply a relatively large force and fasten it efficiently. At that time, as described above, if there is not enough free space around the joint structure, it is difficult for an operator to work using two spanners, and as a result, sufficient tightening force cannot be obtained. there is a possibility. In particular, it is difficult to perform a re-tightening operation when the fastening is loosened after the fastening is once performed.

  Therefore, an object of the present invention is to connect the connecting pipe with high airtightness and high reliability compared to the configuration using the metal gasket without holding the connecting pipe in a twisted state. An object of the present invention is to provide a joint structure that is less likely to generate fine particles.

The present invention relates to a joint structure for connecting a pair of connecting pipes having flanges at their ends, and in a state where the flanges of a pair of connecting pipes are opposed to each other, they are pressed against each other by both flanges. A holder having a metal gasket, a cylindrical portion capable of accommodating the metal gasket, and a claw-shaped engagement portion extending radially inward from a part of the cylindrical portion, the metal gasket being the cylindrical portion The engagement portion engages with at least a part of the metal gasket while being accommodated inside the metal gasket, and the tip of the cylindrical portion is fitted into a concave step portion provided on the flange, thereby making the metal gasket a holder which is held in one of the connecting tube while retaining, in close contact with its outer periphery in a state in which the flange ends of a pair of connecting pipe is opposed across the metal gasket, enclose take periphery of the flanges And centering attachable to, arranged in a sequence, consists of three segments to each other are swingably connected to each other adjacent ones, the segments and the other end located at one end of the three segments A clamp ring that forms a ring shape that covers and holds the entire outer periphery of the flange that faces each other with a metal gasket sandwiched between the segments, when the positioned segments are fixed to each other by the fastening member, Each flange has an inclined surface with a downward slope from the outer periphery to the opposite side of the tip portion, and each segment of the clamp ring has a corresponding inclined surface corresponding to the inclined surface of each flange on the inner periphery. the has an outer diameter of the inner diameter of the metal gasket of the cylindrical portion of the holder is the same size, and smaller than the inner diameter of the centering The outer diameter of the center ring is smaller than the inner diameter of the clamp ring that forms a ring shape with the segment located at one end and the segment located at the other end fixed to each other by the fastening member. A space is provided between the inner surface and the outer diameter of the holder held by the flange by fitting the tip of the cylindrical portion to the stepped portion is smaller than the inner diameter of the center ring. There is a space between the center ring and the inner surface of the center ring. Each flange of the pair of connecting pipes and the metal gasket are arranged so that their inner diameters coincide with each other and their center lines coincide with each other. The metal gasket and each flange are provided with annular protrusions on either one of the surfaces that abut each other. Any surface contacting each other in each flange, characterized in that it is a flat surface perpendicular with respect to neutral alignment inner diameter side from the annular projection.

The clamp ring has a ring shape that covers and holds the entire circumference of the flanges facing each other with a metal gasket in between, and the fastening member brings the segment at one end closer to the segment at the other end Each segment of the clamp ring moves inward in the radial direction while each corresponding inclined surface slides along each inclined surface of each flange, so that the flanges can be held closer together with a metal gasket interposed therebetween. A space is maintained between the outer surface of the center ring and the inner surface of the clamp ring with the flange tips held close together, and between the outer surface of the holder and the inner surface of the center ring. space is maintained, surface abutting each other the metal gasket and the flange, the flange each other tightly across the metal gasket by clamping ring In lifting state, the projection is bite or crushed on the surface facing thereto, in which the flat surfaces of the inner diameter side than the projection is in close contact with each other.

  According to this structure, since sealing is performed using a metal gasket instead of a rubber O-ring, the airtightness is high. And since it is not the structure which screws a nut and a connection pipe together, there is no possibility that a connection pipe may twist at the time of an assembly. As a result, friction does not occur between the connecting pipe and the metal gasket, and there is no possibility of generating fine particles. Furthermore, there is no risk of loose connection due to aging, temperature and humidity changes, and a highly airtight connection can be maintained.

  The fastening member is a bolt for screwing the segment at one end and the segment at the other end, and the segments may be made closer to each other as the bolt is screwed deeper. In this case, it is preferable that the abutting portions of the bolt head and the segment engaging the bolt head of the segments are formed in a spherical shape.

  The fastening member includes a locking portion fastened to one of the segment at one end and the segment at the other end, a screw portion extending from the locking portion, and a screw portion that is screwed to the screw portion. It may be an eyebolt composed of a nut that engages with the nut, and the other segment that engages with the nut may be brought closer to the one segment as the nut is screwed into the threaded portion. In that case, it is preferable that the nut and the other segment are formed in a spherical shape corresponding to each other.

  According to the joint structure of the present invention, since the connecting pipe is not held in a twisted state, high airtightness with respect to the outside of the joint can be secured with a simple configuration. And high airtightness with respect to the exterior of a joint and prevention of generation | occurrence | production of the fine particle which is an impurity inside a joint can be made compatible easily.

  Furthermore, according to the present invention, the fastening member may be tightened strongly in order to improve the connection reliability. In particular, when bolts, nuts, and eyebolts are used as the fastening members, it is not necessary to use a plurality of spanners, and it is only necessary to rotate a driver, a wrench, or the like. These bolts, nuts and eyebolts may be relatively small compared to the overall size of the joint, and do not require a large stroke like a spanner. Therefore, even when a multi-line pipe configuration is provided and a joint structure is included in each pipe line, connection work can be performed with good workability, and connection reliability can be improved.

  Further, according to the present invention, each flange of the pair of connecting pipes and the metal gasket are arranged so that the inner diameters thereof coincide with each other and the center lines thereof coincide with each other. The same peripheral surface is formed with no steps. The surfaces of the metal gasket and the flanges that are in contact with each other are flat surfaces whose inner diameter side is perpendicular to the center line with respect to the annular protrusion. Furthermore, when the flat surfaces are in close contact with each other with the metal gasket sandwiched by the clamp ring, the flanges and the inner peripheral surface of the metal gasket are stepped. It is possible to prevent a gap or a concave portion from being formed in the same peripheral surface that is formed continuously. As a result, it is possible to suppress the risk that the fluid flowing through the joint structure and the substances contained in the fluid remain inside the joint structure.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
1A and 1B show a completed state of the joint structure according to the first embodiment of the present invention. The joint structure of this embodiment is for airtightly connecting a pair of connecting pipes 1a and 1b. The connecting pipes 1a and 1b are formed with flanges 2a and 2b at the ends, respectively. The flanges 2a and 2b are inclined downwardly descending from the outer periphery of the flanges 2a and 2b toward the opposite side of the tip ends of the connection pipes 1a and 1b (inclined inward in the radial direction toward the opposite side of the tip ends of the connection pipes 1a and 1b). Surface 3a, 3b. On the opposing surfaces of the flanges 2a and 2b (end surfaces of the connecting pipes 1a and 1b), annular protrusions (seal beads) 4a and 4b are formed. The protrusions 4a and 4b of both flanges 2a and 2b are formed in the same shape and the same dimensions. Since the inclined surfaces 3a and 3b are provided on the side opposite to the opposing surface of the flanges 2a and 2b (the side opposite to the end surfaces of the connecting pipes 1a and 1b), the connecting pipes 1a and 1b are opposed to each other at their end faces. Thus, if it arrange | positions closely, the trapezoid part (part whose cross-sectional shape is trapezoid) in which both inclined surface 3a, 3b makes a side will be comprised. At this time, the tips of the protrusions 4a and 4b face each other. On the flanges 2a and 2b, stepped portions 5a and 5b are formed on the opposing surface side. These step portions 5a and 5b constitute a small-diameter circumferential surface into which a cylindrical portion 7b of the holder 7 described later is fitted. The connecting pipes 1a and 1b may be a part of a long pipe that allows fluid to flow. However, the connecting pipes 1a and 1b are connecting members (so-called grounds) connected to the end of such a long pipe by welding or the like. Also good.

  Detailed configurations of the connecting pipes 1a and 1b and the metal gasket 6 described later are shown in an enlarged manner in FIGS. 2A to 2C. 2A is a view showing a state in which the connecting pipes 1a and 1b and the metal gasket 6 are separated, FIG. 2B is a view showing a state in the middle of assembling them, and FIG. 2C is a view showing a state in which these assemblings are completed. That is, FIG. 1B is a diagram illustrating the state illustrated in FIG. 1A with members other than the connecting pipes 1a and 1b and the metal gasket 6 having a joint structure omitted.

  2A to 2C, the opposing surfaces of the flanges 2a and 2b (the end surfaces of the connecting pipes 1a and 1b) on the inner diameter side of the protrusions 4a and 4b are center lines of the connecting pipes 1a and 1b. The flat surfaces 20a and 20b are perpendicular to CL. The flat surfaces 20a and 20b need only be substantially perpendicular to the center line CL, and are not required to be so strict. In addition, although the shape of the outer diameter side rather than protrusion 4a, 4b of the opposing surface (end surface of connecting pipe 1a, 1b) of flange 2a, 2b is not specifically limited, compared with flat surface 20a, 20b, connecting pipe 1a, It is in the position retracted to the opposite side to the tip of 1b.

  A flat ring-shaped metal gasket 6 is arranged between the connecting pipes 1a and 1b. In the completed state shown in FIGS. 1A and 2C, the metal gasket 6 is pressed from both sides by the protrusions 4a and 4b. Flat surfaces 21a and 21b perpendicular to the center line CL are formed on the inner diameter side of at least the portions where the protrusions 4a and 4b are abutted on both surfaces of the metal gasket 6. In the present embodiment, the entire both surfaces of the metal gasket 6 are flat surfaces.

  The connecting pipes 1a, 1b and the metal gasket 6 have the same inner diameter D, and are arranged so that the center lines thereof coincide in the completed state of the joint structure. Therefore, the inner peripheral surfaces of the connecting pipes 1a and 1b and the metal gasket 6 constitute the same peripheral surface, and when held tightly by a clamp ring 10 described later, a gap or a recess is formed on the peripheral surface. The connecting pipes 1a, 1b and the flat surfaces 20a, 20b, 21a, 21b of the metal gasket 6 are in close contact with each other so as to disappear. In addition, since each center line of connecting pipe 1a, 1b and metal gasket 6 corresponds, each center line is shown by one line CL in FIG. 2A.

  One connecting pipe 1a holds a holder 7. The holder 7 holds a metal gasket 6 on one connecting pipe 1a. As shown in FIGS. 3 and 4, the holder 7 has a configuration in which a claw-like engagement portion 7 a extending radially inward is provided at one end of the cylindrical portion 7 b. The cylindrical portion 7b has a shape and a size that can be fitted to the stepped portion 5a formed in the connecting pipe 1a. The inner diameter of the engaging portion 7 a is smaller than the outer diameter of the metal gasket 6, and the engaging portion 7 a can be engaged with the metal gasket 6. Therefore, the cylindrical portion 7b is fitted to the step portion 5a of the connecting pipe 1a in a state where the engaging portion 7a is engaged with the outer peripheral portion of the metal gasket 6 and the metal gasket 6 is accommodated inside the holder 7. Be made. As a result, the holder 7 and the metal gasket 6 are held by the connecting pipe 1a. At this time, the metal gasket 6 is in a state where one surface is locked to the engaging portion 7a and the other surface is in contact with the tip of the protrusion 4a of the connecting pipe 1a. In addition, although the engaging part 7a may be provided over the perimeter of the end of the cylindrical part 7b, it may be formed only in a part of inner periphery of the cylindrical part 7b.

  The connecting pipe 1b is disposed so as to face the connecting pipe 1a, and the protrusion 4b is in contact with one surface of the metal gasket 6 held on the connecting pipe 1a by the holder 7 as described above. Thus, the center ring 9 is mounted so as to surround the outer circumferences of the flanges 2a and 2b of the connecting pipes 1a and 1b facing each other (see FIG. 4). Both flanges 2a and 2b have the same shape and the same dimensions, and the outer peripheral surfaces of both flanges 2a and 2b are connected to each other to form a peripheral surface having a constant outer diameter. Therefore, both flanges 2a and 2b are fitted into the center ring 9 having an inner diameter equal to the outer diameter with almost no gap.

  An assembly composed of the connecting pipes 1 a and 1 b, the metal gasket 6, the holder 7 and the center ring 9 having the configuration described above is held by the clamp ring 10. As shown in FIG. 5, the clamp ring 10 has a configuration in which a plurality of (three in the present embodiment) segments 10 a to 10 c are connected in one row. Adjacent segments are connected to each other so as to be relatively swingable about the shaft 15. Each axis 15 is parallel to each other and is an axis perpendicular to the opening / closing operation direction of each segment 10a to 10c. Specifically, the central segment 10 b is connected to the segment 10 a at one end and the segment 10 c at the other end so as to be relatively swingable about the shaft 15. Accordingly, when the segment 10a at one end and the segment 10c at the other end are swung so as to be close to each other, a ring shape can be formed as shown in FIG. 1B.

  Grooves 14 having corresponding inclined surfaces 14a and 14b corresponding to the inclined surfaces 3a and 3b of the connecting pipes 1a and 1b are provided on the inner circumferences of the segments 10a to 10c. As described above, the groove 14 has a shape and size that accommodates a trapezoidal portion having both the inclined surfaces 3a and 3b as both sides when the connecting pipes 1a and 1b are arranged close to each other so as to face each other. .

  A threaded portion 11a of a bolt 11 that is a fastening member is accommodated in the segment 10a at one end, and a groove-shaped notch portion 12 having a size through which the head portion 11b cannot pass is provided. The notch 12 is provided with an enlarged portion 12 a that accommodates the head 11 b of the bolt 11. The segment 10c at the other end is provided with a screw hole 13 into which the screw portion 11a of the bolt 11 is screwed. In each drawing, the male screw part and the female screw part are omitted. As shown in FIG. 1B, a retaining ring is attached to the threaded portion 11 a of the bolt 11.

  With the segments 10a to 10c configured in the ring shape as described above, the head portion 11b of the bolt 11 is accommodated and locked in the enlarged portion 12a of the cutout portion 12 of the segment 10a at one end, and the screw portion 11a is locked. Then, the notch 12 is passed through and screwed into the screw hole 13 of the segment 10c at the other end. Thereby, each segment 10a-10c can be mutually fixed. In the completed state shown in FIGS. 1A and 1B, the flanges 2a and 2b opposed to each other with the metal gasket 6 and the holder 7 interposed therebetween are arranged inside the segments 10a to 10c, and both the inclined surfaces 3a and 3b are placed in the groove 14. A trapezoidal part configured with both sides is inserted. And as above-mentioned, the volt | bolt 11 penetrates the notch part 12, and is screwed and fixed to the screw hole 13 of the segment 10c of the other end. In this configuration, as the bolt 11 is screwed deeper into the screw hole 13, the corresponding inclined surfaces 14a and 14b slide on the inclined surfaces 3a and 3b, and the trapezoidal portion deeply enters the groove 14 in a wedge shape. , 1b of the flanges 2a and 2b try to approach each other. Then, the contact pressure of the protrusions 4a and 4b with respect to the metal gasket 6 increases, and finally, the protrusions 4a and 4b bite into both surfaces of the metal gasket 6, and the flat surface 20a and the flat surface 21a come into surface contact. The flat surface 20b and the flat surface 21b come into surface contact and come into close contact with each other. As a result, the airtightness obtained by the close contact between the metal gasket 6 and the flanges 2a and 2b is enhanced. Utilizing this principle, desired airtightness can be obtained by appropriately setting the screwing amount of the bolt 11 into the screw hole 13. Thus, the joint structure of this embodiment shown in FIGS. 1A and 1B is configured.

  Next, a method for assembling this joint structure will be described.

  First, as shown in FIG. 3, the engaging portion 7a of the holder 7 is engaged with the outer peripheral portion of the metal gasket 6, and the metal gasket 6 is accommodated in the cylindrical portion 7b. In this state, the tubular portion 7b is fitted into the step portion 5a of one connecting pipe 1a. As a result, the metal gasket 6 is held by the connecting pipe 1 a via the holder 7. In addition, by forming the holder 7, the metal gasket 6, and the step portion 5 a with high accuracy, the metal gasket 6 can be securely held on the connecting pipe 1 a with high positional accuracy. Thus, by using the holder 7, the metal gasket 6 is aligned with the connecting pipe 1a. That is, the metal gasket 6 and the center line CL of the connecting pipe 1a are matched.

  Next, as shown in FIG. 4, the other connecting pipe 1 b is disposed so as to face and oppose one connecting pipe 1 a, and the protrusions 4 a and 4 b are brought into contact with both surfaces of the metal gasket 6, respectively. In this state, the center ring 9 is mounted so as to surround the outer peripheries of the flanges 2a and 2b of both the connecting pipes 1a and 1b. Accordingly, the connecting pipe 1b can be aligned with the connecting pipe 1a holding the metal gasket 6 with high positional accuracy so as not to be displaced in a direction perpendicular to the longitudinal direction of the connecting pipes 1a and 1b. it can. However, at this point, the members are in an approximately appropriate positional relationship (the center lines CL of the metal gasket 6 and the connecting pipes 1a and 1b are all coincident), but are not yet fixed and have high airtightness. Sex has not been obtained.

  Therefore, the clamp ring 10 is used to firmly fix each member and improve the airtightness of the connection between the connection pipes 1a and 1b. As shown in FIG. 5, the opened segments 10a to 10c are closed to form a ring shape, and the flanges 2a and 2b of the connecting pipes 1a and 1b are confined inside. At this time, as shown in FIGS. 6A and 6B, trapezoidal portions configured with the inclined surfaces 3 a and 3 b of the flanges 2 a and 2 b as both sides are inserted into the groove 14. As described above, the bolt 11 is fixed by being screwed into the screw hole 13 of the segment 10c at the other end through the notch 12.

  As shown in FIGS. 6A and 6B, when the screwing amount of the bolt 11 into the screw hole 13 is small, the interval between the segment 10a at one end and the segment 10c at the other end is not sufficiently narrow. That is, the inner diameter of the ring shape (ring shape formed by the groove 14) formed by the segments 10a to 10c is not yet sufficiently small. Therefore, the amount of insertion of the trapezoidal portion configured with the inclined surfaces 3a and 3b of the flanges 2a and 2b as both sides into the groove 14 is small. Therefore, the flanges 2a and 2b are not so close to each other when viewed in the longitudinal direction of the connecting pipes 1a and 1b. 6A and 6B, the protrusions 4a and 4b are in contact with both surfaces of the metal gasket 6, but the contact pressure is low, and the flat surfaces 20a, 20b, 21a and 21b are in contact with each other. Not. That is, the state shown in FIG. 2B. As a result, at this point in time, the airtightness sufficient to block the gas flow is not obtained, and the joint structure is insufficient as it is.

  Therefore, the bolt 11 is further screwed into the screw hole 13. As shown in FIGS. 1A and 1B, when the screwing amount of the bolt 11 into the screw hole 13 is increased, the interval between the segment 10a at one end and the segment 10c at the other end is sufficiently narrowed. And the internal diameter of the ring shape (ring shape which the groove | channel 14 comprises) which each segment 10a-10c comprises becomes small enough. Therefore, the amount of insertion of the trapezoidal portion configured with the inclined surfaces 3a, 3b of the flanges 2a, 2b as both sides into the groove 14 is increased. Therefore, the distance between the flanges 2a and 2b is sufficiently small when viewed in the longitudinal direction of the connecting pipes 1a and 1b. In this state, the protrusions 4a and 4b are pressed against both surfaces of the metal gasket 6 with a large contact pressure, the protrusions 4a and 4b bite into both surfaces of the metal gasket 6, and the metal gasket 6 is slightly recessed. Then, the flat surface 20a on the inner diameter side of the protrusion 4a of the flange 2a and the flat surface 21a on the inner diameter side of the metal gasket 6 are in close contact with each other, and the flat surface 20b on the inner diameter side of the protrusion 4b of the flange 2b is in contact with the metal. The flat surface 21b on the inner diameter side of the gasket 6 is in close contact with the surface. That is, the state shown in FIG. 2C is obtained. As a result, the flanges 2a and 2b and the metal gasket 6 can block the gas flow by the press contact of the protrusions 4a and 4b and the flat surfaces 20a, 20b, 21a and 21b, and have sufficient airtightness as a joint structure. can get.

  It should be noted that the screwing amount of the bolt 11 to obtain sufficient airtightness may be obtained in advance by a preliminary test or the like, but during the assembly process of the joint structure described above (the screwing operation of the bolt 11 into the screw hole 13). During middle), the airtightness may be checked as needed, and the screwing operation may be stopped when sufficient airtightness has been confirmed.

  As shown in FIG. 1B, when a sufficient screwing amount of the bolt 11 into the screw hole 13 is obtained, the notch 12 and the screw hole 13 are aligned so that the bolt 11 is held horizontally. Has been. Then, the head 11 b of the bolt 11 is stably held in the enlarged portion 12 a of the notch 12. However, during the screwing operation, that is, when the screwing amount is still insufficient, as shown in FIG. 6B, the notch 12 and the screw hole 13 are not aligned, and the bolt 11 is oblique to the notch 12. Is held. At this time, the head portion 11 b of the bolt 11 comes in partial contact with the inner wall of the enlarged portion 12 a of the notch 12. Therefore, in the present embodiment, the contact portions of the head portion 11b and the enlarged portion 12a of the notch portion 12 are formed in corresponding spherical shapes having substantially the same curvature. As a result, no matter which part of each abutting part abuts in a biased manner, there is no corner, so that the head 11b or the notch 12 may be damaged or the bolt may be hindered. There is no.

  In addition, in this embodiment, not only the connection part 1a is provided with the step part 5a, but the connection part 1b is also provided with the step part 5b. Although this step portion 5b is not necessary in terms of configuration, in order to reduce the labor and cost of production by using a pair of connection pipes 1a and 1b having exactly the same configuration, in this embodiment, a connection having the step portion 5b is provided. A tube 1b is used.

  In this embodiment, the flanges 2a and 2b having a relatively thick and complicated shape are provided. However, it is also possible to form a flange having a simple shape in which the end surfaces of the connection pipes 1a and 1b are expanded. However, as described above, the inclined surfaces 3a and 3b for constituting the trapezoidal portion that enters the groove 14 and produces the rust effect are necessarily provided.

  As described above, in this embodiment, as shown in FIG. 2A, the flanges 2a, 2b and the metal gasket 6 have the same inner diameter D, and the respective center lines CL coincide with each other. The same peripheral surface is formed with no steps. Moreover, since the flat surface 20a and the flat surface 21a, and the flat surface 20b and the flat surface 21b are in close contact with each other, there are no gaps or recesses in the peripheral surface formed by each inner peripheral surface. The technical significance will be described below.

  Conventionally, when the inner diameters of the flanges 2a and 2b and the metal gasket 6 are different from each other, a step is generated at the joint portion of each inner peripheral surface, and a convex portion or a concave portion is generated. Further, when the flat surfaces perpendicular to the center line CL are not provided on the inner diameter side portions of the opposing surfaces of the flanges 2a and 2b and both surfaces of the metal gasket 6, the flanges 2a and 2b and the metal gasket are provided. Both surfaces of 6 do not make surface contact with each other. For example, as illustrated in FIG. 7, when the inner diameter side portions of the respective surfaces are tapered surfaces 22 a and 22 b, respectively, between the tapered surfaces 22 a and 22 b and the metal gasket surfaces 21 a and 21 b, respectively. A gap 23 is generated. In this case, it is possible to obtain high airtightness by strongly pressing the protrusions 4 a and 4 b against both surfaces of the metal gasket 6. However, there is a possibility that a gap (concave portion) 23 is generated in the fluid path, and a substance is accumulated in the gap 23. That is, when such a gap 23 is formed on the peripheral surface formed by the inner peripheral surfaces of the flanges 2a and 2b and the metal gasket 6, the fluid (particularly liquid) flowing through the joint structure and the fluid There is a possibility that the contained substance enters the gap 23 and is captured. In addition, even when a convex portion is generated on the peripheral surface, there is a possibility that the fluid or a substance contained in the fluid is captured by the step portion located at the base of the convex portion. Thus, when the fluid trapped in the joint structure and the substances contained therein are fermented or viruses and bacteria are generated and grown, there is a possibility that it becomes a big problem especially when handling food and drink as a fluid. In addition, it becomes difficult to sufficiently wash the fluid before the other fluid is circulated next, and there is a possibility of causing problems such as contact with another fluid and reaction.

  On the other hand, in the joint structure of the present invention, as described above, when the clamp ring 10 is tightened, gaps (concave portions) or steps are formed on the peripheral surfaces formed by the inner peripheral surfaces of the flanges 2a and 2b and the metal gasket 6. It can be absent (see FIG. 2C). Therefore, it is possible to prevent the fluid (particularly liquid) flowing through the joint structure and the substances contained in the fluid from being trapped, and in particular, to avoid the problem in the joint structure through which the food and drink fluid flows.

[Second Embodiment]
FIG. 8 shows a second embodiment of the joint structure of the present invention. In addition, about the structure similar to 1st Embodiment, the same code | symbol is provided and description is abbreviate | omitted.

  In this embodiment, eyebolts 16 are used instead of the bolts 11. The eyebolt 16 includes a threaded portion 16a and a locking portion 16b that is swingably attached to the segment 10c by a pin 17. The threaded portion 16a can be inserted into the cutout portion 12 of the segment 10a. Then, a nut 18 is screwed into the screw portion 16a, and the nut 18 engages with the enlarged portion 12a of the notch portion 12. Each contact portion of the nut 18 and the enlarged portion 12a of the notch 12 is formed in a corresponding spherical shape having substantially the same curvature.

  The joint structure of the present embodiment can achieve the same effects as those of the first embodiment, and can simplify the assembly work by using the eyebolt 16.

  According to the joint structure of the first and second embodiments of the present invention described above, high airtightness can be obtained by pressing the protrusions 4a and 4b of the flanges 2a and 2b on both surfaces of the metal gasket 6, respectively. Moreover, when the flanges 2a and 2b are fixed using the clamp ring 10, the force for rotating the connecting pipes 1a and 1b itself does not work, so that the connecting pipes 1a and 1b are not twisted. As a result, no friction occurs between the metal gasket 6 and the protrusions 4a and 4b, and no fine particles are generated. Even if it is used for a long time or even if some expansion or contraction occurs in each member due to temperature change, the connecting pipes 1a and 1b do not rotate relative to the metal gasket 6, and friction does not occur. Fine particles are not generated. According to this joint structure, not only high airtightness to the outside can be obtained, but also residual impurities and bacteria in the inside can be prevented. This is especially true when a highly accurate fluid flow is required, such as a gas supply unit of a semiconductor manufacturing device, or when a beverage liquid such as a can filling device or various dispensers (beverage dispensing device) is used. It is suitable when a clean state is required.

  Further, according to the joint structure of the present invention, there can be no gaps (concave portions) or steps on the peripheral surfaces formed by the inner peripheral surfaces of the flanges 2a and 2b and the metal gasket 6, so that the inside of the joint structure It is possible to reduce the risk that the fluid flowing through the fluid and the substances contained in the fluid remain in the joint structure. In the configuration shown in FIGS. 1A and 2C, the annular protrusions 4a and 4b provided on the flanges 2a and 2b bite into both surfaces of the metal gasket 6, and the both surfaces of the metal gasket 6 are slightly recessed, so that they are flat. The surfaces 20a, 20b, 21a, and 21b can be closely attached. However, although not shown, concave portions corresponding to the protrusions 4a and 4b are formed in advance on both surfaces of the metal gasket 6, and the flat surfaces 20a, 20b, 21a and 21b may be in close contact with each other. Further, the metal gasket 6 may not be deformed, and the flat surfaces 20a, 20b, 21a, 21b may be in close contact with each other by the protrusions 4a, 4b being pressed against both surfaces of the metal gasket 6 and being crushed. . Further, the protrusions may be formed on both surfaces of the metal gasket 6 instead of the flanges 2a and 2b. In that case, the protrusions on both surfaces of the metal gasket 6 bite into the end faces of the flanges 2a and 2b and the end faces of the flanges 2a and 2b are recessed, or the protrusions are pressed against the end faces of the flanges 2a and 2b and crushed. Thus, the flat surfaces 20a, 20b, 21a, and 21b may be brought into close contact with each other. Moreover, the recessed part corresponding to protrusion may be previously provided in each end surface of flange 2a, 2b, respectively.

  In the joint structure of the present invention described above, the connection pipes 1a and 1b may be a part of a long pipe through which fluid flows, but for connection connected to the end of such a long pipe by welding or the like. It may be a member (so-called ground). The joining by welding in the latter case may be a so-called butt joining in which the end faces of the long pipe and the ground are brought into contact with each other, and one end is inserted into the other end. It may be a so-called plug-in type welding that is welded with a screw. Further, the pipe connected to the gland may be configured to use a tubular or opening-shaped inlet / outlet portion provided in a casing of a device that supplies or discharges fluid, and the gland is attached to the inlet / outlet portion. .

It is front sectional drawing of the joint structure of the 1st Embodiment of this invention. It is a side view of the joint structure of a 1st embodiment of the present invention. It is front sectional drawing which shows the state which mutually separated the pair of connection pipe and metal gasket of the joint structure shown in FIG. It is front sectional drawing which shows the state in the middle of joining of a pair of connecting pipe and metal gasket of the joint structure shown in FIG. It is front sectional drawing which shows the joining completion state of a pair of connecting pipe and metal gasket of the joint structure shown in FIG. It is front sectional drawing which shows the assembly process of the joint structure of the 1st Embodiment of this invention. It is front sectional drawing which shows the assembly process following FIG. 3 of the joint structure of the 1st Embodiment of this invention. It is a perspective view of the state where the fastening member was removed and opened of the clamp ring used for the joint structure of a 1st embodiment of the present invention. It is front sectional drawing which shows the assembly process following FIG. 4 of the joint structure of the 1st Embodiment of this invention. It is a side view which shows the assembly process following FIG. 4 of the coupling structure of the 1st Embodiment of this invention. FIG. 2C shows the joint completion state of the pair of connection pipes and the metal gasket of the joint structure of the reference example for comparison with the joint completion state of the pair of connection pipes and the metal gasket of the joint structure of the present invention shown in FIG. 2C. It is front sectional drawing. It is a side view of the joint structure of the 2nd Embodiment of this invention.

Explanation of symbols

1a, 1b Connecting pipe 2a, 2b Flange 3a, 3b Inclined surface 4a, 4b Protrusion 5a, 5b Step 6 Metal gasket 7 Holder 7a Engaging portion 7b Cylindrical portion 9 Center ring 10 Clamp ring 10a-10c Segment 11 Bolt 11a Screw portion 11b Head portion 12 Notch portion 12a Enlarged portion 13 Screw hole 14 Grooves 14a, 14b Corresponding inclined surface 15 Shaft 16 Eye bolt 16a Screw portion 16b Locking portion 17 Pin 18 Nut 20a, 20b Flat surface 21a, 21b Flat surface CL Center line D Inner diameter

Claims (6)

In a joint structure for connecting a pair of connecting pipes having flanges at their ends,
A flat ring-shaped metal gasket which is pressed from both sides by the flanges in a state where the flanges of the pair of connecting pipes face each other;
A holder having a cylindrical part capable of accommodating the metal gasket therein and a claw-like engaging part extending radially inward from a part of the cylindrical part, wherein the metal gasket is provided on the cylindrical part. With the engagement portion engaged with at least a part of the metal gasket while being housed inside, the tip of the cylindrical portion is fitted into a concave step provided on the flange, A holder that is held by one of the connecting pipes while holding the metal gasket ;
In a state that the flange between the connection tube of the pair are opposed across the metal gasket, a wearable centering so as to be in close contact with the circumference Nde the periphery take periphery of said flanges,
A series arranged in, consist of three segments to each other are swingably connected to each other adjacent ones, segments and fastening member located in the segment and the other end located at one end of the three segments A clamp ring that forms a ring shape that covers and holds the entire outer periphery of the flange facing each other across the metal gasket, with all the segments,
Have
Each of the flanges has an inclined surface with a downward slope from the outer periphery to the opposite side of the end,
Each segment of the clamp ring has a corresponding inclined surface corresponding to the inclined surface of each flange on the inner peripheral portion,
The inner diameter of the cylindrical portion of the holder and the outer diameter of the metal gasket are the same size, and smaller than the inner diameter of the center ring,
The outer diameter of the center ring is smaller than the inner diameter of the clamp ring that forms a ring shape with a segment located at the one end and a segment located at the other end fixed to each other by the fastening member. A space is provided between the outer surface and the inner surface of the clamp ring,
The outer diameter of the holder held by the flange by fitting the tip of the cylindrical portion to the stepped portion is smaller than the inner diameter of the center ring, and the outer surface of the holder and the inner surface of the center ring are There is a space between
The flanges of the pair of connecting pipes and the metal gasket are arranged so that their respective inner diameters coincide with each other and their respective centerlines coincide with each other.
An annular protrusion is provided on one of the surfaces of the metal gasket and the flanges that are in contact with each other, and the surfaces of the metal gasket and the flanges that are in contact with each other are more than the annular protrusions. The inner diameter side is a flat surface perpendicular to the center line,
A joint structure characterized by that. The clamp ring is in a state of forming a ring shape that covers and holds the entire circumference of the outer periphery of the flange that faces each other with the metal gasket interposed therebetween, and the fastening member is connected to the segment at the one end and the other end at the other end. The closer the segments are, the more the segments of the clamp ring move inward in the radial direction while the corresponding inclined surfaces slide along the inclined surfaces of the flanges. Is capable of holding the flanges more closely together,
A space is maintained between the outer surface of the center ring and the inner surface of the clamp ring in a state where the tips of the flanges are held close to each other, and the outer surface of the holder and the inner surface of the center ring A space is maintained between
The surfaces of the metal gasket and the flanges that are in contact with each other are bitten or crushed by the clamp ring in a state where the flanges are held tightly with the metal gasket sandwiched between the projections. The flat surfaces on the inner diameter side of the protrusions are in close contact with each other.
The joint structure according to claim 1.   The joint according to claim 1 or 2, wherein the fastening member is a bolt for screwing the segment at the one end and the segment at the other end, and the two segments can be brought closer to each other as the bolt is screwed deeper. Construction.   The joint structure according to claim 3, wherein a contact portion of each of the bolt head and the segment engaging the bolt head among the segments is formed in a spherical shape.   The fastening member is screwed into the screw portion, a locking portion fastened to one of the segment at the one end and the segment at the other end, a screw portion extending from the locking portion, and the screw portion. 2. The eyebolt comprising a nut that engages with the other segment, and the other segment that engages with the nut can be brought closer to the one segment as the nut is screwed into the threaded portion. Or the joint structure of 2.   The joint structure according to claim 5, wherein the nut and the other segment are formed in a spherical shape corresponding to each other.

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