JP2014219042A - Gas seal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas seal device which exhibits excellent seal function even for gas containing liquid or solid state foreign matter.SOLUTION: An inside gas region A and an outside atmospheric region B are sealed via a purge region C between a noncontact mechanical seal 1 and a labyrinth seal 2. The seal 1 seals a purge gas region C and the outside atmospheric region B by supplying seal gas S having a pressure higher than the inside gas region A to between seal edge surfaces 7a, 8a. The seal 2 includes a seal body 25 attachably and detachably fastened to an outer circumferential surface of a sleeve 6, a labyrinth body 26 attachably and detachably attached to a seal case 4, and a purge gas supply passage 27 for supplying purge gas P having a pressure lower than the seal gas S and higher than gas of the inside gas region A to the purge gas region C, and divides and seals the inside gas region A and the purge gas region C on a relative rotation part of both bodies 25, 26. A drain passage 32 is connected with the purge gas region C.

Description

  The present invention relates to a gas used as a shaft seal for a rotating device (for example, a blower for a product gas installed in a blast furnace of a steelworks) that handles a gas containing liquid or solid foreign matters (slurry, slag, etc.). The present invention relates to a sealing device.

  In this type of gas seal device, a rotary seal ring on the rotary shaft side and a stationary seal ring on the seal case side are configured to generate static pressure by supplying a seal gas between the seal end faces which are opposite end faces of both seal rings. A non-contact type mechanical seal configured to seal an in-machine gas region as an internal region of a rotating device and an external air region as an external region while holding the sealed end face in a non-contact state is well known (for example, , See Patent Document 1).

  Such a non-contact type mechanical seal is different from an end surface contact type mechanical seal in which the sealing end surface is in relative rotational sliding contact, and does not cause problems such as seizure of the sealing end surface even under dry conditions. It is preferably used as a shaft sealing means.

JP 2010-25201 A

  However, if the gas to be sealed contains liquid or solid foreign matter such as slurry or slag, the foreign matter may enter between the sealed end faces in a non-contact state, or adhere to and accumulate on the sealed end faces. There is a fear. When such a situation occurs, the static pressure between the sealing end faces cannot be properly controlled, and the sealing function is reduced or lost.

  An object of the present invention is to provide a gas seal device capable of exhibiting and maintaining a good sealing function over a long period of time without causing the above-described problem even in a rotating device that handles such foreign-containing gas. Is.

  The present invention, which has solved this problem, forms an in-machine gas region and an out-of-machine air region of a rotating device between the two seals by a non-contact mechanical seal on the out-of-machine air region side and a labyrinth seal on the in-machine gas region side. A gas seal device configured to seal via a purge gas region, wherein a non-contact mechanical seal is detachably attached to an outer end of a shaft seal portion casing of a rotating device; A sleeve fixed to the rotary shaft of the rotating device concentrically through the seal case, a stationary seal ring held in the seal case movably in the axial direction, and an in-machine gas region from the stationary seal ring A rotating seal ring fixed to the sleeve in a state of being directly opposite to the stationary seal ring, and being interposed between the seal case and the stationary seal ring to turn the stationary seal ring into the rotary seal ring A pressure energizing spring, and a seal gas supply passage that is formed in the seal case and the stationary seal ring and supplies a high-pressure seal gas from the in-machine gas region between the seal end faces that are the opposite end faces of both seal rings, It is configured to seal the purge gas region and the outside air region at the relative rotation part of both sealed end surfaces while maintaining the non-contact state between the sealed end surfaces by the static pressure generated between the sealed end surfaces by the gas supply. The labyrinth seal is a cylindrical member having an outer peripheral surface as the labyrinth seal surface, and is positioned on the in-machine gas region side of the rotary seal ring and detachably fixed to the outer peripheral surface of the sleeve; A labyrinth body that is detachably attached to the seal case and has a plurality of annular protrusions on the inner peripheral portion thereof that are close to and opposed to the labyrinth seal surface and are arranged in parallel in the axial direction. A purge gas supply passage formed in the seal case and supplying a purge gas having a pressure lower than that of the seal gas and higher than that of the gas in the machine to the purge gas region, and a relative rotation portion between the labyrinth seal surface and the labyrinth body The drain gas passage is configured so as to partition and seal the in-machine gas region and the purge gas region, and a drain passage having one end opened to the purge gas region is formed in the seal case, and a drain having an on-off valve at the other end of the drain passage. The present invention proposes a gas seal device characterized in that pipes are connected.

  In such a gas seal device, the labyrinth seal surface has the same diameter or the same diameter as the outer peripheral surface of the sleeve portion and the rotary seal ring located on the atmosphere side outside the machine. In a state where the rotary side sealing element including the rotary seal ring is fixed to the rotary shaft, the static side seal element including the seal case and the static seal ring and the labyrinth body attached thereto is not disassembled as an integral structure. It is preferably configured to be detachably attachable to the shaft seal casing, and further, by a set screw provided at the end of the sleeve on the outside air region side, an integral structure without disassembling the rotary side sealing element It is preferable to be configured to be removably fixed to the rotating shaft as an object.

  The gas seal device of the present invention connects the in-machine gas region and the outside air region via a purge gas region formed between both seals by a non-contact mechanical seal on the outside air region side and a labyrinth seal on the in-machine gas region side. Since sealing is performed, a satisfactory sealing function can be exhibited even when the in-machine gas contains liquid or solid foreign matter. In addition, when foreign matter enters the purge gas region, it can be quickly discharged from the drain passage, and the foreign matter intrusion into the purge gas region can be accurately detected by the property of the exhaust gas from the drain passage. Further, it is possible to prevent a situation in which the sealing function of the non-contact type mechanical seal is lowered or lost due to the foreign matter. Further, the pressure in the purge gas region can be adjusted by opening and closing the drain passage, and thereby, the sealing function by the non-contact type mechanical seal between the purge gas region and the outside air region can be satisfactorily exhibited. Therefore, according to the present invention, it is possible to provide a gas seal device that exhibits a good sealing function over a long period of time even when the in-machine gas contains liquid or solid foreign matter.

  Further, the sealing case 4 and the stationary side sealing element and the stationary side sealing element including the labyrinth body attached thereto and the sleeve, and the rotary side sealing element including the rotational sealing ring provided on the sealing case 4 and the rotary side sealing element provided therein are integrated without being disassembled. By configuring so as to be removable from the shaft seal casing and the rotating shaft as an object, maintenance of the labyrinth seal including replacement work of the seal body and / or labyrinth body can be easily performed. Therefore, the labyrinth seal and the non-contact mechanical seal can function well over a long period of time, and it is extremely practical as a shaft seal means for a rotating device that handles gas containing liquid or solid foreign matter. A gas seal device can be provided.

FIG. 1 is a longitudinal side view showing an example of a gas seal device according to the present invention. FIG. 2 is a longitudinal front view taken along line II-II in FIG. FIG. 3 is a half-longitudinal longitudinal side view corresponding to FIG. 1 showing a state in which the seal case of the gas seal device is removed.

  Hereinafter, the form for implementing this invention is demonstrated concretely based on FIGS. 1-3.

  1 is a longitudinal side view showing an example of a gas seal device according to the present invention, FIG. 2 is a longitudinal front view taken along the line II-II of FIG. 1, and FIG. 3 is a state of removing a seal case of the gas seal device. FIG.

  The gas seal device shown in FIG. 1 is a horizontal rotary device that handles gas containing liquid foreign matters or solid foreign matters (hereinafter referred to as “in-machine gas”) (for example, generated gas (slurry and / or slurry) installed in a blast furnace of an ironworks. Or converter gas containing slag or mixed gas) blower) shaft sealing means, the in-machine gas region A as the internal region of the rotating equipment and the out-of-air region B as the external region, The non-contact type mechanical seal 1 on the outside air region B side and the labyrinth seal 2 on the in-machine gas region A side are sealed via a purge gas region C formed between the seals 1 and 2. In the following description, front and rear mean the left and right in FIG. 1 or FIG. 3, and upper and lower mean the upper and lower in FIG. 1 or FIG.

  As shown in FIG. 1, the non-contact type mechanical seal 1 includes a cylindrical seal case 4 attached to an outer end 3 a of a shaft seal portion casing 3 of a rotating device, and the rotation passing through the seal case 4 concentrically. A sleeve 6 inserted and fixed to the rotating shaft 5 of the device, a stationary seal ring 7 held in the seal case 4 so as to be movable in the axial direction, and a stationary seal ring 7 located on the in-machine gas region A side of the stationary seal ring 7 A rotating seal ring 8 fixed to the sleeve 6 in a state of being directly opposed to the sleeve, and a spring interposed between the seal case 4 and the stationary seal ring 7 to press and bias the stationary seal ring 7 to the rotary seal ring 8 9 and a seal gas supply passage 10 which is formed in the seal case 4 and the stationary seal ring 7 and supplies a high-pressure seal gas S from the in-machine gas region A between the seal end faces 7a and 8a which are opposite end faces of the seal rings 7 and 8. And a seal gas The purge gas region C and the atmosphere outside the machine are maintained at the relative rotation portions of the sealed end surfaces 7a and 8a while maintaining the non-contact state between the sealed end surfaces 7a and 8a by the static pressure generated between the sealed end surfaces 7a and 8a. It is a non-contact mechanical seal of a static pressure type configured to seal the region B.

  As shown in FIG. 1, the seal case 4 is a cylindrical structure that is detachably attached to the outer end (front end) 3a of the shaft seal casing 3 in a horizontal manner. The case main bodies 4a and 4b and the holding body 4c. , 4d, and 4e. That is, the case main body is an integral structure composed of a cylindrical main body portion 4a and an annular mounting portion 4b projecting from the outer periphery of the intermediate portion in the axial direction of the main body portion 4a. As shown in FIG. 1, the case main bodies 4a and 4b have through-holes 4f formed in a mounting portion 4b in a plurality of screw shafts 11 (only one is shown) protruding horizontally from the outer end 3a of the shaft seal portion casing 3. And the nut 12 is screwed and tightened so that the front end portion (rear end portion) of the main body portion 4a is inserted into the shaft seal portion casing 3, and is attached to and detached from the outer end 3a of the shaft seal portion casing 3. It is attached as possible. The holding body includes an annular flange portion 4c, a cylindrical holding portion 4d protruding from the inner peripheral end portion of the front end surface (rear end surface) of the flange portion 4c into the main body portion 4a, and a radial direction at the front end surface. It is an integral structure comprising a cylindrical locking portion 4e that is concentric with the holding portion 4d from the intermediate portion and protrudes into the main body portion 4a. As shown in FIG. 1, the holding bodies 4c, 4d, and 4e are formed by screwing a plurality of bolts 13 (only one shown) inserted into the outer peripheral side portion of the flange portion 4c into the main body portion 4a. The outer peripheral side portion of 4c is abutted against the base end portion (front end portion) of the main body portion 4a and is integrally connected to the case main bodies 4a and 4b with the locking portion 4e fitted inside the main body portion 4a.

  As shown in FIG. 1, the sleeve 6 is integrally composed of a cylindrical main body portion 6a inserted through the rotary shaft 5 and an annular receiving portion 6b formed to bulge at the front end portion (rear end portion). The sleeve main body, the thick cylindrical fixing portion 6c inserted through the rotating shaft 5, and the outer peripheral portion (rear end outer peripheral portion) of the main body 6a extend in the axial direction to the base end portion (front end portion) of the main body portion 6a. It is divided into a mounting body integrally formed with the fitted thin cylindrical pressing portion 6d. Thus, as shown in FIG. 1, the sleeve 6 includes a plurality of bolts 14 (only one shown) inserted through the fixing portion 6c and screwed into the main body portion 6a to attach the mounting bodies 6c and 6d to the sleeve main body 6a, A plurality of set screws 16 (only one is shown) that are screwed into a fixed portion 6c that is an end of the sleeve 6 on the outside air region B side of the sleeve 6 are assembled by being attached to 6b. By being fastened to the shaft 5, it is fixed to the rotating shaft 5 so as to be detachable. The outer diameter of the sleeve 6 is maximum at the receiving portion 6b, and the outer diameters of the sleeve portions 6c and 6d on the side of the outside air region B from the receiving portion 6b are the same.

  The stationary seal ring 7 is held in the seal case 4 so as not to be relatively rotatable and movable in the axial direction (front-rear direction) while being loosely fitted concentrically with the pressing portion 6 d of the sleeve 6. That is, as shown in FIG. 1, the stationary seal ring 7 is in a secondary seal state in which a pair of front and rear first and second O-rings 17 and 18 whose outer peripheral surfaces are arranged in parallel at a predetermined interval are interposed. By holding the inner peripheral surface of the main body portion 4a on the outer peripheral surface of the holding portion 4d of the seal case 4 in a secondary seal state with the third O-ring 19 interposed therebetween, the seal case 4 is held so as to be movable in the axial direction. Further, as shown in FIG. 1, the stationary seal ring 7 is installed in the flange portion 4c of the seal case 4 in a plurality of engagement recesses 7b (only one is shown) drilled in the base end portion (front end portion). By engaging the drive pin 20, relative rotation with respect to the seal case 4 is prevented in a state where axial movement within a certain range is allowed. In this example, the stationary sealing ring 7 is an annular body made of carbon, and its front end surface (rear end surface) is configured as a sealed end surface 7a which is a smooth annular plane perpendicular to the axis. A sealed space 22 sealed by the first and third O-rings 17 and 19 is formed between the opposed peripheral surfaces of the seal case 4 and the stationary seal ring 7. As shown in FIG. 1, a back pressure introducing hole 23 that connects the sealed space 22 and the purge gas region C is formed, and the fluid pressure of the purge gas region C introduced into the sealed space 22 from the back pressure introducing hole 23 is statically sealed. It is devised to act as a back pressure that presses the ring 7 against the rotary seal ring 8. The pressing force acting on the stationary sealing ring 7 by this back pressure acts as a closing force in a direction in which the sealing end surfaces 7a and 8a are closed together with a pressing force (biasing force) by a spring 9 described later.

  The rotary seal ring 8 is disposed on the in-machine gas region A side (rear side) of the stationary seal ring 7 and is fixed to the rotary shaft 5 via the sleeve 6. That is, as shown in FIG. 1, the rotary seal ring 8 is disposed in the main body portion 4a of the seal case 4, and is fitted to the main body portion 6a of the sleeve 6 in a state of being directly opposed to the stationary seal ring 7, and the bolt. By fastening 14, the sleeve 6 is fixed to the sleeve 6 while being pressed between the receiving portion 6 b and the pressing portion 6 d of the sleeve 6. The front end surface (front end surface) of the rotary sealing ring 8 is configured as a sealing end surface 8a which is a smooth annular plane orthogonal to the axis. In this example, the rotary sealing ring 8 is an annular body made of a metal such as stainless steel, and a ceramic layer 8b is formed on the front end surface of the rotary sealing ring 8, and the sealing end surface 8a is constituted by the ceramic layer 8b. . Further, the rotary seal ring 8 is rotated by engaging the drive pin 21 implanted in the receiving portion 6b of the sleeve 6 with the engagement recess 8c formed at the base end portion (rear end portion) thereof. Relative rotation with respect to the shaft 5 is prevented.

  As shown in FIG. 1, the spring 9 is composed of a plurality of coil springs (only one is shown) interposed between the stationary seal ring 7 and the flange portion 4c of the seal case 4 at equal intervals in the circumferential direction. Thus, the stationary seal ring 7 is pressed and urged to the rotary seal ring 8 to generate a closing force that acts in the direction of closing the sealing end faces 7a and 8a.

  As shown in FIG. 1, the seal gas supply path 10 is a series formed in the seal case 4 and the stationary seal ring 7, and the communication formed between the opposed peripheral surfaces of the stationary seal ring 7 and the seal case 4. A space 10a, a case-side passage 10b that passes through the main body 4a of the seal case 4 and communicates with the communication space 10a, a static pressure generating groove 10c formed in the sealing end surface 7a of the stationary sealing ring 7, and the stationary sealing ring 7 , A sealed ring side passage 10d extending from the communication space 10a to the static pressure generating groove 10c, and an orifice 10e disposed in the sealed ring side passage 10d. The pressure is higher than the pressure in the in-machine gas region A and the purge gas region C. Is supplied to the static pressure generating groove 10c to generate a static pressure (opening force) acting in a direction to open the sealing end surfaces 7a and 8a.

  As shown in FIG. 1, the communication space 10 a is an annular space formed between the opposed peripheral surfaces of the stationary seal ring 7 and the main body 4 a of the seal case 4, and is a first space loaded between the opposed peripheral surfaces. And second O-rings 17 and 18. The first O-ring 17 is prevented from jumping out from the communication space 10a to the atmosphere outside the machine B by the locking portion 4e of the seal case 4, and the communication space 10a of the second O-ring 18 to the purge gas region C is prevented. The protrusion is prevented by an annular locking portion 4g protruding from the inner peripheral surface of the main body portion 4a of the seal case 4. In addition, an annular convex portion 7c protruding into the communication space 10a is formed on the outer peripheral surface of the stationary seal ring 7 to prevent the O-rings 17 and 18 from approaching a certain distance. As shown in FIG. 3, when the seal case 4 is removed from the shaft seal casing 3, the annular protrusion 7 c is brought into contact with the second O-ring 18, so that the stationary seal ring 7 by the biasing force of the spring 9 is obtained. Is prevented from falling off from the seal case 4 (holding portion 4d and locking portion 4e). Of course, the seal case portion that holds the stationary seal ring 7, that is, the holding portion 4 d and the locking portion 4 e are necessary to hold the stationary seal ring 7 in a state where the annular convex portion 7 c abuts against the second O-ring 18. Needless to say, it has a sufficient length in the axial direction.

  The case-side passage 10b is connected to a seal gas supply pipe 24 led from a predetermined seal gas supply source (not shown) at the upstream end thereof, and the gas in the in-machine gas region A (in-machine gas) and will be described later. A seal gas S having a pressure higher than that of the purge gas P is supplied to the communication space 10a.

  The static pressure generating groove 10c is a shallow concave groove that is continuous or intermittent in a ring concentric with the sealing end surface 7a of the stationary sealing ring 7. In this example, the latter is adopted. That is, as shown in FIG. 2, the static pressure generating groove 10c is composed of a plurality of arc-shaped concave grooves that are concentrically arranged in parallel with the sealed end surface 7a.

  As shown in FIG. 1, the sealing ring side passage 10 d has an upstream end opened to the communication space 10 a on the outer peripheral surface of the annular convex portion 7 c of the stationary sealing ring 7, and a downstream end portion ( A portion downstream of the orifice 10e) 10f is branched and opened in each static pressure generating groove 10c, and the seal gas S supplied from the case side passage 10b to the communication space 10a is supplied to each static pressure generating groove 10c. Let

  Thus, when the seal gas S is supplied from the case side passage 10b to the static pressure generation grooves 10c through the communication space 10a and the sealing ring side passage 10d, the seal gas S introduced into the static pressure generation grooves 10c is used. An opening force is generated between the sealed end faces 7a and 8a that acts in the direction of opening the sealing end faces 7a and 8a. This opening force is due to the static pressure generated by the sealing gas S introduced between the sealing end faces 7a and 8a. Therefore, the sealing end surfaces 7a and 8a are held in a non-contact state in which the opening force balances with the spring load acting in the closing direction between the sealing end surfaces 7a and 8a and the closing force acting on the sealed space 22 due to the back pressure. . That is, the seal gas S introduced into the static pressure generating groove 10c forms a static pressure fluid film between the sealed end faces 7a and 8a, and is an outer diameter side region of the sealed end faces 7a and 8a due to the presence of this fluid film. The space between the purge gas region C and the outside air region B which is the inner diameter side region is shield-sealed. The pressure of the sealing gas S and the spring force (spring load) of the spring 9 are appropriately set according to the sealing conditions so that the gap between the sealed end faces 7a and 8a is appropriate (generally 5 to 15 μm). By the way, since the seal gas S is leaked from the sealed end faces 7a and 8a to the purge gas region C and the outside air region B, the seal gas S is harmless even if released into the atmosphere and has an adverse effect on the in-machine gas. Appropriate properties are selected according to the sealing conditions. In this example, clean room temperature nitrogen gas that is inert to various substances and harmless to the human body is used. The supply of the seal gas S from the seal gas supply pipe 24 is performed during the operation of the rotating device (during the driving of the rotating shaft 5), and is stopped after the operation is stopped. The operation of the rotating device is started after the supply of the seal gas S is started and after the sealed end faces 7a and 8a are maintained in a proper non-contact state, and the supply of the seal gas S is stopped. This is performed after the operation of the rotating device is stopped and after the rotating shaft 5 is completely stopped.

  Further, since the sealing gas S is throttled by the orifice 10e and then introduced into the static pressure generating groove 10c, even when the gap between the sealed end faces 7a and 8a fluctuates, the gap is automatically adjusted to be appropriate. Retained. That is, when the clearance between the sealing end surfaces 7a and 8a becomes large due to vibration of the rotating device, etc., static pressure is generated through the orifice 10e and the amount of sealing gas flowing between the sealing end surfaces 7a and 8a from the static pressure generating groove 10c. Since the amount of seal gas supplied to the groove 10c becomes unbalanced, the pressure in the static pressure generating groove 10c decreases and the opening force becomes smaller than the closing force, so that the gap between the sealed end faces 7a and 8a becomes small. And the gap is adjusted to an appropriate value. On the contrary, when the gap between the sealed end faces 7a and 8a becomes small, the pressure in the static pressure generating groove 10c increases due to the restriction function by the orifice 10e as described above, and the opening force becomes larger than the closing force. The gap between the sealing end faces 7a and 8a is changed so as to increase, and the gap is adjusted to an appropriate one.

  As shown in FIG. 1, the labyrinth seal 2 is a cylindrical member whose outer peripheral surface is a labyrinth seal surface 25 a and is positioned on the in-machine gas region A side of the rotary seal ring 8 and can be attached to and detached from the outer peripheral surface of the sleeve 6. A fixed seal body 25, and a labyrinth body 26 that is detachably attached to the seal case 4 and has a plurality of annular convex portions 26a that are close to and opposed to the labyrinth seal surface 25a and that are arranged in parallel in the axial direction. A purge gas supply passage 27 that is formed in the seal case 4 and that supplies a purge gas P that is lower in pressure than the seal gas S and higher in pressure than the in-machine gas to the purge gas region C, so that the labyrinth seal surface 25a and the labyrinth body 26 are The in-machine gas area A and the purge gas area C are partitioned and sealed in the rotating portion.

  As shown in FIG. 1, the seal body 25 is a cylindrical member having an L-shaped cross section having an annular mounting flange 25 b at the base end portion (rear end portion), and the outer peripheral surface of the receiving portion 6 b of the sleeve 6. The mounting flange 25b is fixed to the sleeve 6 in a detachable manner by attaching the mounting flange 25b to the front end surface (rear end surface) of the receiving portion 6b with a plurality of bolts 28 (only one is shown). The outer diameter of the seal body 25, that is, the diameter of the labyrinth seal surface 25 a that is the outer peripheral surface of the seal body 25 is set to be the same as or larger than the outer diameter of the rotary seal ring 8.

  As shown in FIG. 1, the labyrinth body 26 is an annular body in which a plurality of annular protrusions 26 a that are arranged in parallel in the axial direction are formed on the inner peripheral portion. A ring-shaped protrusion 30 in a state of being engaged with an annular recess 4h formed on the inner peripheral portion of the rear end of the main body 4a of the seal case 4 by an annular mounting body 30 attached with a bolt 29 (only one is shown) 26a is detachably attached to the seal case 4 in a state of facing the labyrinth seal surface 25a.

  As shown in FIG. 2, the purge gas supply passage 27 is a through-hole penetrating the main body 4a of the seal case 4 on the horizontal diameter line, and has a downstream end opened to the purge gas region C as shown in FIG. It is. A purge gas supply pipe 31 is connected to the upstream end of the purge gas supply passage 27 via an orifice (not shown), and supplies a seal gas P lower in pressure than the seal gas S and higher in pressure than the in-machine gas to the purge gas region C. To do. That is, the seal gas S is slowly supplied to the purge gas region C without being ejected from the purge gas supply passage 27 by passing through the orifice, and the purge gas region C is maintained in a purge gas atmosphere having a higher pressure than the in-machine gas region A. The properties of the purge gas P are selected based on the same criteria as the selection criteria for the seal gas S described above. In this example, nitrogen gas having the same properties as the seal gas S is used.

  Therefore, according to the labyrinth seal 2, the annular convex portion 26 a formed on the inner peripheral portion of the labyrinth body 26 and the labyrinth seal surface 25 a that is the outer peripheral surface of the seal body 25 relatively rotate in the proximity state, whereby this relative rotation. The outer diameter side region of the sealing end faces 7a, 8a of the non-contact type mechanical seal 1 is partly sealed with the in-machine gas region A, and the outer diameter side region is purged with a purge gas P that is higher than the in-machine gas region A. C

  Further, as shown in FIGS. 1 and 2, the seal case 4 is a through-hole penetrating the lower portion of the main body 4a in the vertical direction and having an upper end that is one end opened to the purge gas region C. A passage 32 is formed. A drain pipe 33 having an on-off valve 33a is connected to the lower end which is the other end of the drain passage 32.

  In the gas seal device configured as described above, the purge gas P having a pressure higher than the in-machine gas is supplied to the purge gas region C formed between the labyrinth seal 2 and the non-contact mechanical seal 1. The gas regions A and C are partitioned and sealed by a labyrinth seal 2 on the in-machine gas region A side. Further, since the seal gas S having a pressure higher than the purge gas S is ejected from the sealed end faces 7a and 8a of the non-contact type mechanical seal 1 to the outside air region B and the purge gas region C, there is no gap between the gas regions B and C. Sealed by a contact-type mechanical seal 1. Therefore, the in-machine gas region A is reliably sealed between the in-machine gas region A and the outside air region B through the higher pressure purge gas region C, and the in-machine gas does not leak into the out-of-machine air region B. That is, since the purge gas region C has a higher pressure than the in-machine gas region A, the in-machine gas hardly leaks from the labyrinth seal 2 to the purge gas region C, and the sealing end faces 7a and 8a of the non-contact mechanical seal 1 are sealed. Since the gas S is ejected to the purge region C, leakage from the purge gas region C to the outside air region B is reliably prevented.

  In addition, when liquid foreign matters such as slurry and sludge contained in the in-machine gas or solid foreign matters (hereinafter collectively referred to as “foreign matter”) enter the purge gas region C from the in-machine gas region A through the labyrinth seal 2. By opening the on-off valve 33a and opening the drain passage 32, the foreign matter can be quickly discharged from the purge gas region C, and the sealing function of the non-contact type mechanical seal 1 by the foreign matter as described at the beginning is reduced by the foreign matter. There is no loss or loss. Since such opening of the drain passage 32 can be performed during operation of the rotary device, the gas properties of the purge gas region C can be always accurately grasped by periodically opening the drain passage 32 by the on-off valve 33a. (That is, whether or not foreign matter has entered the purge gas region C can be accurately detected), and problems caused by foreign matter entering and depositing in the purge gas region C can be prevented. Further, the pressure in the purge gas region C can be adjusted by opening and closing the drain passage 32, and the pressure in the purge gas region C can be properly maintained.

  Therefore, according to the gas seal device having the above-described configuration, the in-machine gas can be well and properly sealed.

  By the way, the labyrinth seal 2 is such that the opposing peripheral surface of the seal body 25 and the labyrinth body 26, that is, the labyrinth seal surface 25a that is the outer peripheral surface of the seal body 25 and the inner peripheral surface of the annular convex portion 26a of the labyrinth body 26 are relatively close to each other. Since the sealing function is exhibited by rotating, both the 25a and 26a come into contact with each other due to vibration of the rotating device, and one or both of them may be worn and damaged, and the sealing function by the labyrinth seal 2 may be lowered. .

  Therefore, in such a case, it is preferable to replace the seal body 25 and / or the labyrinth body 26. However, in the gas seal device having the above configuration, the gas seal device is attached to the seal case 4 and the seal case 4 as shown in FIG. The stationary side sealing element M1 including the stationary sealing ring 7, the spring 9 and the labyrinth body 26, and the rotary side sealing element M2 including the sleeve 6 and the rotary sealing ring 8 provided on the stationary side sealing element M1. The replacement work of the seal body 25 and / or the labyrinth body 26 is configured so as to be detachable from the shaft seal casing 3 and the rotary shaft 5 as an integral structure without disassembling M1 and the rotary shaft side sealing element M2. Can be performed very easily.

  That is, since the outer diameter of the seal body 25 to which the labyrinth body 26 is adjacent is the same as or larger than the outer diameter of the rotary seal ring 8, the labyrinth body 26 attached to the seal case 4 has the rotary seal ring 8. Can be moved in the axial direction without interfering with the rotation-side sealing element M2 including Therefore, as shown in FIG. 3, by removing the nut 12 from the screw shaft 11 and moving the seal case 4 in the axial direction, the stationary side sealing element M1 can be removed from the shaft seal casing 3 as an integral structure. . As described above, the stationary seal ring 7 can be formed by the annular projection 7c being abutted and locked to the second O-ring 18 even when the seal case 4 is removed from the shaft seal casing 3. It is prevented from falling off from the seal case 4 due to the urging force, and is loosely fitted in the sleeve portions 6c and 6d on the outside air region B side from the fixed sealing ring 8 so as to be freely inserted and removed.

  Therefore, the labyrinth body 26 can be replaced while the stationary side sealing element M1 is in the assembled state by moving the stationary side sealing element M1 out of the shaft seal portion casing 3 and then detaching the attachment body 30 with the bolt 29. It can be carried out. After the labyrinth body 26 is replaced, the gas seal device is formed by screwing and tightening the nut 12 to the bolt shaft 11 inserted into the mounting portion 4b of the seal case 4 again with the stationary side sealing ring M1 assembled. Can be reassembled.

  If the sealing body 25 is damaged, the stationary side sealing element M1 is removed as described above, and then the set screw 16 is operated to move the rotational side sealing element M2 to pivot the sealing body 25. By bringing it out of the sealing casing 3, the bolt 28 can be detached and the sealing body 25 can be replaced. After the replacement of the seal body 25, the rotary side sealing element M <b> 2 is moved to the original position shown in FIG. 3 and fixed to the rotary shaft 5 by the set screw 16. Thereafter, the gas seal device can be reassembled by attaching the stationary side sealing element M1 to the shaft seal casing 3 as described above.

  Thus, since the sealing body 25 and / or the labyrinth body 26 can be replaced and the gas sealing device can be reassembled without disassembling the stationary side sealing element M1 and the rotary side sealing element M2, the sealing elements M1, M2 can be replaced. Compared to the case where one or both of them need to be disassembled, the replacement work of the seal body 25 and / or the labyrinth body 26 can be performed very easily and in a short time, and the property analysis of the exhaust gas from the drain passage 32 is performed. Combined with the ability to indirectly detect the deterioration of the sealing function of the labyrinth seal 2, it is possible to prevent the deterioration of the sealing function of the labyrinth seal 2 and thus the sealing function of the gas sealing device, and the sealing function of the gas sealing device can be extended for a long time. Can be satisfactorily exhibited.

  It should be noted that the present invention is not limited to the above-described embodiment, and can be improved and changed as appropriate without departing from the basic principle of the present invention.

DESCRIPTION OF SYMBOLS 1 Non-contact type mechanical seal 2 Labyrinth seal 3 Shaft seal casing 3a External end 4 Seal case 4a Body (case body)
4b Mounting part (case body)
4c Flange (holding body)
4d Holding part (holding body)
4e Locking part (holding body)
4f Through hole 4g Locking portion 4h Annular recess 5 Rotating shaft 6 Sleeve 6a Body (sleeve body)
6b Receiving part (sleeve body)
6c Fixed part (mounting body)
6d Pressing part (mounting body)
7 stationary sealing ring 7a sealing end surface 7b engagement recess 7c annular projection 8 rotating sealing ring 8a sealing end surface 8b ceramic layer 8c engagement recess 9 spring 10 seal gas supply path 10a communication space 10b case side passage 10c static pressure generating groove 10d sealing Ring side passage 10e Orifice 10f Downstream end 11 Screw shaft 12 Nut 13 Bolt 14 Bolt 15 Bolt 16 Set screw 17 First O-ring 18 Second O-ring 19 Third O-ring 20 Drive pin 21 Drive pin 22 Sealed space 23 Back pressure Introduction hole 24 Seal gas supply pipe 25 Seal body 25a Labyrinth seal surface 25b Mounting flange 26 Labyrinth body 26a Annular projection 27 Purge gas supply passage 28 Bolt 29 Bolt 30 Attachment body 31 Purge gas supply pipe 32 Drain passage 33 Drain pipe 3 a shutoff valve A machine gas region B outside air region C purge region M1 stationary seal element M2 rotary side sealing element P purge S seal gas

Claims (3)

The in-machine gas region and the outside air region of the rotating equipment are sealed with a non-contact mechanical seal on the outside air region side and a labyrinth seal on the in-machine gas region side through a purge gas region formed between the two seals. A gas seal device configured as follows:
Non-contact type mechanical seal can be inserted into and removed from a cylindrical seal case that is detachably attached to the outer end of the shaft seal casing of the rotating device, and the rotating shaft of the rotating device that concentrically penetrates the seal case. , A stationary seal ring held axially movable in the seal case, and a rotation fixed to the sleeve in a state of being directly opposite to the stationary seal ring, located on the gas region side of the stationary seal ring. A sealing ring, a spring interposed between the sealing case and the stationary sealing ring to press and bias the stationary sealing ring to the rotating sealing ring, and opposite end surfaces of the sealing case and the stationary sealing ring formed on both sealing rings A sealing gas supply path for supplying a high-pressure sealing gas from the in-machine gas region is provided between the sealing end surfaces, and the sealing end surfaces are not contacted by the static pressure generated between the sealing end surfaces by supplying the sealing gas. While maintaining the state, it is configured to seal the purge gas region and outside air region in the relative rotation portions of both sealing end faces,
The labyrinth seal is a cylindrical member having an outer peripheral surface as a labyrinth seal surface, and is positioned on the in-machine gas region side of the rotary seal ring and detachably fixed to the outer peripheral surface of the sleeve, and a seal case A labyrinth body having a plurality of annular protrusions in the inner peripheral portion, which are mounted in a detachable manner and face each other in close proximity to the labyrinth seal surface and parallel in the axial direction, and a seal case formed from the seal gas in the purge gas region A purge gas supply passage for supplying a purge gas at a low pressure and a pressure higher than the gas in the in-machine gas region, so that the in-machine gas region and the purge gas region are section-sealed at a relative rotation portion between the labyrinth seal surface and the labyrinth body. Configured,
A gas seal device, wherein a drain passage having one end opened to a purge gas region is formed in a seal case, and a drain pipe having an on-off valve is connected to the other end of the drain passage.   The labyrinth seal surface has the same diameter or the same diameter as the outer peripheral surface of the sleeve portion and the rotary seal ring located on the outside air region side from this, and the rotary side including the sleeve and the rotary seal ring attached thereto With the sealing element fixed to the rotary shaft, the stationary side sealing element including the sealing case and the stationary sealing ring and labyrinth body attached thereto is detachably attached to the shaft sealing casing as an integral structure without disassembling. The gas seal device according to claim 1, wherein the gas seal device is configured to be able to. The sleeve is configured to be removably fixed to the rotating shaft as an integral structure without disassembling the rotating side sealing element by a set screw provided at the end of the sleeve on the outside air region side. The gas seal device according to claim 2.

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