JP7291064B2 - Shaft seal device - Google Patents

Description

The present invention relates to a shaft seal device having a non-contact mechanical seal.

As shown in Patent Document 1, a non-contact mechanical seal is a non-contact state in which a stationary seal ring held in a seal case so as to be axially movable and a rotary seal ring fixed to a rotating shaft have a minute gap. It rotates relatively to seal the gas.

Therefore, in the non-contact mechanical seal, it is necessary to constantly monitor whether the gap formed between the two seal rings is a proper gap.

Therefore, in the conventional non-contact type mechanical seal, as described in Patent Document 1, page 2, line 13, page 3, line 4, a gas flow meter is used to check whether the two seal rings have an appropriate gap. Alternatively, as disclosed in FIG. 1 of Patent Document 1, a non-contact sensor is provided in a non-through hole formed in the stationary seal ring from its base end side. It is proposed to detect by

Japanese Utility Model No. 04-084868

However, from the change in the amount of gas, it is only possible to roughly grasp whether or not the clearance between the two seal rings is appropriate when leakage occurs from the two seal rings. cannot be accurately determined. On the other hand, when using a non-contact sensor, the gap between both seal rings is directly detected, so it is possible to accurately grasp whether the gap is proper or not. It requires extensive processing, such as drilling a hole to accommodate the sensor.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a shaft seal device having a non-contact mechanical seal that does not require a large amount of processing on the stationary seal ring and can accurately grasp the gap between the two seal rings.

In order to achieve this object, the present invention provides a seal case having a spring retainer hanging down from the end on the side of the machine's outer region and a retainer extending from the inner peripheral part thereof toward the side of the machine's inner region, and a seal case capable of axial movement on the retainer. A non-contact type mechanical seal comprising a stationary seal ring held by a body and a rotating seal ring fixed to a rotating shaft facing the stationary seal ring, so that both seal rings are relatively rotated in a non-contact state. wherein an abnormality detection device includes a plate to be measured provided on the base end face of the stationary seal ring and a non-contact device provided on the spring retainer for measuring the distance between the plate to be measured A shaft sealing device is proposed, comprising: a contact sensor; and an alarm that issues an alarm when a value detected by the non-contact sensor deviates from a threshold range.

In a preferred embodiment of such a shaft sealing device, the non-contact type mechanical seal is arranged on the outside area side of the machine, and the seal ring provided on the seal case and the rotary A contact-type mechanical seal is provided that rotates relative to a seal ring provided on the shaft in a contact state, and a purge gas is supplied to a region defined by both mechanical seals. In this case, the stationary seal ring comprises a seal ring main body facing the rotary seal ring and a pressing body connected to the seal ring main body via an O-ring, and the plate to be measured is the pressing body. The seal case is formed with a purge gas supply passage through which the purge gas is supplied toward the stationary seal ring and a drain passage through which the purge gas is discharged from the vicinity of the rotary seal ring. is preferred. Moreover, it is preferable that the plate to be measured is integrally formed with the base end surface of the stationary seal ring.

In the shaft sealing device of the present invention, the distance between the plate to be measured provided on the base end surface of the stationary seal ring and the non-contact sensor provided on the spring retainer of the seal case is measured, and this distance falls within the threshold range. Since an alarm is issued when the seal rings come off, it is possible to accurately grasp when the clearance between the two seal rings is not within the proper clearance, and the stationary seal ring does not need to be machined significantly.

1 is a sectional view showing an example of a shaft sealing device according to the present invention; FIG. FIG. 2 is a detailed view showing an enlarged main part of FIG. 1; FIG. 5 is a partially cutaway cross-sectional view showing a modification of the shaft sealing device according to the present invention;

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated based on drawing.

FIG. 1 is a cross-sectional view showing an example of a shaft sealing device according to the present invention, and FIG. 2 is a detailed view showing an enlarged main part of FIG.

As shown in FIG. 1, the shaft sealing device according to the present invention is installed in rotating equipment such as a pump that handles liquid. A purge gas region C formed between the mechanical seals 1 and 2 is divided by the end face contact type mechanical seal 1 on the side and the non-contact type mechanical seal 2 on the outside region side. .

As shown in FIG. 1, the end face contact type mechanical seal 1 on the side of the machine interior seals the liquid (sealed fluid) in the machine interior area A. A seal case 4 is attached to the shaft seal portion casing 3 of the rotating equipment. , a seal ring (fixed seal ring) 5 fixed to the seal case 4 and a seal ring (movable seal ring) held movably in the axial direction on a rotating shaft 6 of the rotating equipment that passes through the seal case 4 concentrically. ) 7 and a spring 8 that presses the movable seal ring 7 against the fixed seal ring 5, and the seal end faces 5a and 7a, which are the opposite end faces of the two seal rings 5 and 7, are brought into relative rotational sliding contact to effect sealing. An in-machine area A, which is an outer peripheral area of the end faces 5a and 7a, and a purge gas area C, which is an inner peripheral area thereof, are partitioned.

The seal case 4 includes an inboard area side main body 4a attached to the shaft seal portion casing 3 of the rotating equipment, an outboard area side main body 4b attached to the inboard area side main body 4a, and an outboard area side main body 4b. A metallic cylindrical structure consisting of a ring plate-shaped spring retainer 4c hanging down from the outer region side end, and a cylindrical holder 4d integrally formed on the inner peripheral portion of the spring retainer 4c and extending in the direction of the internal region A. is. A supply passage 9 for supplying the flushing liquid F is formed in the in-machine region side main body 4a. , 7a.

The stationary seal ring 5 has a sealing end face 5a, which is a smooth annular flat surface perpendicular to the axis, and is fixed to the base end of the main body 4a of the seal case 4 on the side of the machine interior. The stationary seal ring 5 is made of carbon or the like.

A sleeve 10 having both ends 10 a and 10 b projecting from the seal case 4 is fitted to the rotary shaft 6 . The sleeve 10 has a base end portion 10a protruding from the seal case 4 toward the outside of the machine, and a fixing ring 11 is fitted to the base end portion 10a. It is fixed to the rotating shaft 6 by screwing together a suitable number of the second screws 12b which are tightened to the same. An appropriate number of connecting claws 13 engaged with an annular concave portion 10c formed in a sleeve 10 are attached to the end portion of the seal case 4 on the side of the outside of the machine so that the mechanical seals 1 and 2 can be rotated in an assembled state. It is designed to be attached and detached from the equipment.

The movable seal ring 7 is attached to a metal seal ring holder 7b which is axially movably held at the tip 10b of the sleeve 10 through an O-ring 14, and to the tip of the seal ring holder 7b by shrink fitting or the like. It consists of a fixed seal ring main body 7c and a metal sleeve receiver 7d connected to the proximal end of the seal ring holder 7b so as not to rotate relative to each other. The seal ring main body 7c has a sealing end surface 7a which is a smooth annular flat surface perpendicular to the axis, and is made of a material harder than the material of the stationary seal ring 5 (ceramics such as silicon carbide, tungsten carbide, etc.). etc.). The movable seal ring 7 (seal ring main body 7c) is moved relative to the sleeve 10 (rotating shaft 6) by engaging a drive pin 15 provided on the spring receiver 7d with a spring retainer 16 fixed to the tip portion 10b of the sleeve 10. Rotation is blocked.

The spring 8 is loaded between the spring receiver 7d of the movable seal ring 7 and the spring retainer 16 and urges the seal ring main body 7b of the movable seal ring 7 against the stationary seal ring 5. As shown in FIG.

As shown in FIG. 1, the non-contact mechanical seal 2 on the outboard region side moves in the axial direction between the outboard region side main body 4b, the spring retainer 4c and the holding body 4d of the seal case 4, and the holding body 4d of the seal case 4. a stationary seal ring 18 held so as to be possible; a rotary seal ring 19 disposed opposite the stationary seal ring 18 and fixed to the rotating shaft 6; With a spring 20 loaded between them, the sealing end faces 18a, 19a, which are the opposing end faces of both the sealing rings 18, 19, are relatively rotated while being held in a non-contact state by the dynamic pressure generated therebetween. It is of a dynamic pressure type configured to separate the purge gas region C, which is the outer peripheral region of the sealing end faces 18a and 19a, from the outer region B, which is the inner peripheral region thereof.

A purge gas supply passage 21 for supplying the purge gas P to the purge gas region C and a drain passage 22 for discharging the purge gas P from the purge gas region C are provided in the outer region side body 4b of the seal case 4 . As the purge gas P, a gas that does not interfere with leakage to the outside area (atmospheric area) B and is inert to the liquid in the inside area A is selected. In this example, nitrogen gas is used.

As shown in FIGS. 1 and 2, the stationary seal ring 18 includes a seal ring main body 18b held by the holder 4d of the seal case 4 so as to be movable in the axial direction, and an O-ring 23 at the proximal end of the seal ring main body 18b. and a pressing body 18c made of metal (titanium, stainless steel, or the like) connected via a metal. The seal ring main body 18b is made of carbon or the like, and has a sealing end face 18a, which is a smooth annular flat surface perpendicular to the axis. The seal ring main body 18b of the stationary seal ring 18 is prevented from rotating relative to the seal case 4 by a drive pin (not shown) provided between the seal ring body 18b and the spring retainer 4c of the seal case 4. As shown in FIG.

The rotary seal ring 19 consists of a metal seal ring holder 19b fixed to the sleeve 10 via an O-ring 24, and a seal ring main body 19c fixed to the tip of the seal ring holder 19b via an O-ring 25. Consists of The seal ring body 19c is made of carbon, ceramics such as silicon carbide, cemented carbide such as tungsten, or the like. The end face of the seal ring main body 19c is configured as a sealing end face 19a which is a smooth annular plane orthogonal to the axis, and a dynamic pressure generating groove 19d opening to the purge gas region C is formed in the sealing end face 19a. The dynamic pressure generating groove 19d is formed by forming a shallow groove such as a spiral opening to the purge gas region C in the sealing end surface 19a of the sealing ring main body 19c.

The spring 20 is loaded between the pressing body 18c of the stationary seal ring 18 and the spring retainer 4c of the seal case 4, and pushes the seal ring main body 18b of the stationary seal ring 18 to the rotating seal ring 19 via the pressing body 18c. It is biased in the direction of the seal ring body 19c.

By the way, the purge gas supply passage 21 is supplied with the purge gas P toward the seal ring main body 18b of the stationary seal ring 18, and the supplied purge gas P passes through the stopper ring 4e provided in the inner peripheral portion of the outer region side main body 4b of the seal case 4. , part of which flows out from between the sealing end faces 18a, 19a of both seal rings 18, 19 into the external region B, and the other part flows along the outer peripheral surface of the rotary seal ring 19. The liquid flows out to the side of the seal ring holder 19b and flows out from the drain passage 22 together with the liquid that has leaked into the purge gas region C from the sealing end faces 5a and 7a of the mechanical seal 1 on the inboard region side.

According to the non-contact mechanical seal 2 on the outside area side, the purge gas P in the purge gas area C is caught between the sealing end face 18a of the stationary seal ring 18 and the sealing end face 19a of the rotary seal ring 19, and both sealing end faces 18a are formed. , 19a to maintain both sealing end faces 18a, 19a in a non-contact state with a minute gap (appropriate gap). A portion of the purge gas P supplied to the purge gas region C from the purge gas supply passage 21 passes between the sealing end surfaces 18a and 19a of the two seal rings 18 and 19 and is discharged to the external region (atmospheric region) B, and the other part The liquid that has leaked from the end face contact type mechanical seal 1 on the side of the internal region is discharged from the drain passage 22 along with the liquid.

Therefore, in the shaft sealing device according to the present invention, when the sealing function of the non-contact type mechanical seal 2 on the outside area side is not functioning, the abnormality detection device 26 detects this and issues an alarm. is provided.

That is, as shown in FIG. 1, the abnormality detection device 26 is provided on the plate 27 to be measured provided on the base end surface of the stationary seal ring 18 and the spring retainer 4c of the seal case 4, and is provided between the plate 27 to be measured. A non-contact sensor 28 that measures distance, a controller 29 that compares the detection value of the non-contact sensor 28 with a threshold value, and an alarm device 30 that issues an alarm when the value detected by the non-contact sensor 28 deviates from the threshold value. and

A plate 27 to be measured provided on the base end surface of the stationary seal ring 18 is provided on the base end surface of the pressing body 18c of the stationary seal ring 18 so as to be perpendicular to the axis. In this example, since the pressing member 18c is made of a conductive metal material (titanium or the like), the plate 27 to be measured is integrally formed with the pressing member 18c, and the pressure is applied according to the detection range of the non-contact sensor 28. The body 18c is integrally formed with a part protruding from the proximal end face of the body 18c.

As shown in FIGS. 1 and 2, the spring retainer 4c of the seal case 4 is provided with a non-contact type measuring plate 27 provided on the base end surface of the stationary seal ring 18 (base end surface of the pressing body 18c). A sensor 28 is provided. As the non-contact sensor 28, for example, a non-contact sensor that measures the distance from the plate 27 to be measured by eddy current is used, and a male screw is formed on the outer periphery. The non-contact sensor 28 has a horizontally penetrating screw hole 4f formed in the spring retainer 4c, and the non-contact sensor 28 is screwed into this screw hole 4f. The non-contact sensor 28 is screwed in with both ends slightly projecting from the spring retainer 4c, and a nut 31 is screwed to the base end projecting from the spring retainer 4c. The nut 31 is screwed to the non-contact sensor 28 via a sealing member 32 such as a gasket between the nut 31 and the spring retainer 4c, thereby sealing between the non-contact sensor 28 and the spring retainer 4c. The seal member 32 seals the non-contact sensor 28 from the spring retainer 4c in the purge area C. As shown in FIG.

The distance T between the tip of the non-contact sensor 28 and the plate 27 to be measured of the stationary seal ring 18 is, as shown in FIG. It is set to a distance when the gap is a proper gap. That is, the distance is the threshold T. Then, the controller 29 compares the value detected by the non-contact sensor 28 with the threshold value T, and when the detected value is out of the range of the threshold value T, the alarm device 30 issues an alarm (sound, light, etc.).

According to the shaft sealing device configured as described above, the liquid in the inboard area A is sealed by the mechanical seal 1 on the inboard area side. The leak is accompanied by the purge gas P by the non-contact type mechanical seal 2 and discharged from the drain passage 22. - 特許庁On the other hand, part of the purge gas P is discharged from the purge gas area C to the outside area B. As shown in FIG.

Then, when the sealing function of the non-contact type mechanical seal 2 on the outside area side becomes improper for some reason, and the gap between the sealing end surfaces 18a, 19a of the two seal rings 18, 19 widens or narrows from the appropriate gap. That is, when the detected value of the non-contact sensor 28 is out of the range of the threshold value T (when it exceeds the upper limit value or when it falls below the lower limit value), the alarm device 30 issues an alarm. When an alarm is issued, stop the equipment and inspect and repair the non-contact mechanical seal 2. Immediately after the operation of the non-contact mechanical seal 2 is started, the sealing end surfaces 18a and 19a of both the seal rings 18 and 19 do not reach the proper gap, and the detected value by the non-contact sensor 28 is the lower limit of the threshold value T. , no alarm is issued in this case.

At this time, since the non-contact type sensor 27 is provided on the spring retainer 4c which hangs down from the end of the seal case 4 on the outside area side, the sensor disclosed in FIG. The stationary seal ring and the seal case holding it need not be processed in a complicated manner, and the seal ring main body 18b of the stationary seal ring 18 does not need to be processed for the non-contact sensor 28. do not have. Therefore, the seal ring main body 18b of the stationary seal ring 18 and the holder 4d of the seal case 4 which holds the seal ring body 18b do not need to be processed in any way. Since it is only necessary to provide the screw hole 4f, the non-contact sensor 28 can be easily attached to the existing shaft sealing device. Further, since the non-contact sensor 28 issues an alarm only when the detected value is out of the range of the threshold value T, the distance between the sealing end surfaces 18a, 19a of both the sealing rings 18, 19 exceeds the proper distance. It is possible to accurately grasp the point in time.

Further, since the pressing member 18c of the stationary seal ring 18 is made of a conductive metal material (titanium or the like), the sealing body 18b of the stationary seal ring 18 is made of a material such as carbon that is not excellent in conductivity or a non-conductive material. Moreover, it is not necessary to compose the mating seal ring (seal ring main body 19b of the rotary seal ring 19) from a conductive material as in Patent Document 1. Further, since the plate to be measured 27 is provided on the pressing body 18c, which is not directly related to the function of the stationary seal ring 18, the plate to be measured 27 can be formed integrally with the pressing body 18c. If the portion is not within the detection range of the non-contact sensor 27, a portion that protrudes outside the pressing body 18c can be formed. Therefore, the seal ring main body 18b of the stationary seal ring 18 and the seal ring main body 19b of the rotary seal ring 19 can be made of the original material of the seal rings, and the constituent materials are not limited.

Also, the liquid leaked from the in-machine region A flows out from the drain passage 22, but the verge gas P accompanied by this liquid does not pass near the non-contact sensor 28. As shown in FIG. That is, the non-contact sensor 28 is sealed between the spring retainer 4c of the seal case 4 and the stopper ring 4e by the seal member 32, and only clean purge gas P supplied from the purge gas supply passage 21 enters there. As a result, the non-contact sensor 28 does not become dirty or malfunction because it does not come into contact with the purge gas P entrained with the liquid flowing out from the drain passage 22 . Therefore, the operation of the non-contact sensor 28 is always well maintained.

It should be noted that the configuration of the shaft sealing device of 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.

For example, the end face contact type mechanical seal 1 on the machine interior side may be composed of a movable seal ring held axially movably in the seal case 4 and a fixed seal ring fixed to the rotating shaft 2 . Further, the shaft seal device can be applied to the case where the end surface contact type mechanical seal 1 is not provided and the dynamic pressure type non-contact type mechanical seal 2 is used as a single seal. In this case, the sealed fluid is is gas. Of course, the stationary seal ring 18 may be constructed as a single seal ring. It is preferable that the measurement plate 27 is made of a metal material.

The shaft sealing device of the present invention can also be applied to a static pressure non-contact mechanical seal 40 as shown in FIG. That is, the hydrostatic non-contact type mechanical seal 40 has a main body 42a attached to a shaft seal casing 41 of a rotating device, and an annular plate-shaped spring retainer 42b suspended from the end of the main body 42 on the outside region side. A seal case 42 integrally formed with a cylindrical holder 42c extending in the machine interior region A direction on the inner periphery of a spring retainer 42b, and the holder 42c of the seal case 42 is axially movable via an O-ring 43. A stationary seal ring 44 made of retained carbon or the like, a rotating seal ring 47 made of carbon, ceramics or the like fixed to a sleeve 46 fitted to a rotating shaft 45 of the rotating device so as to face the stationary seal ring 44, A spring (not shown) loaded between the base end of the stationary seal ring 44 and the spring retainer 42b of the seal case 42 to press the stationary seal ring 44 toward the rotary seal ring 47; 42a and a static pressure generating groove 44b formed in the sealing end surface 44a of the stationary seal ring 44 are communicated with each other. The purge gas injection passages 49 , 50 , 51 are spaces sealed by O-rings 52 , 53 between the inner periphery of the main body 42 a of the seal case 42 and the outer periphery of the stationary seal ring 44 and connected to the purge gas supply passage 48 . 49, a passage 50 formed in the stationary seal ring 44 from the space 49 and connected to the static pressure generating groove 44b, and an orifice 51 interposed in the passage 50. Therefore, by supplying the purge gas P from the purge gas supply passage 48 to the static pressure generating groove 44b of the stationary seal ring 44, static pressure is generated between the sealing end face 44a of the stationary seal ring 44 and the sealing end face 47a of the rotary seal ring 47. and hold the sealing end faces 44a, 47a of both the sealing rings 44, 47 in a non-contact state.

The static pressure type non-contact type mechanical seal 40 is provided with an abnormality detection device 54 similar to the abnormality detection device 26 described above. That is, as shown in FIG. 3, the abnormality detection device 54 includes the same non-contact sensor 28, controller 29 and alarm 30 as described above, and a plate 55 to be measured provided on the base end surface of the stationary seal ring 44. equip. The non-contact sensor 27 is screwed into a horizontal screw hole 4 f formed in the spring retainer 42 b of the seal case 42 and fixed with a nut 31 via a seal member 32 . The plate 55 to be measured is provided on the base end surface of the stationary seal ring 44. Since the stationary seal ring 44 is made of carbon or the like, which is not excellent in conductivity, the base end surface of the stationary seal ring 44 is provided with a metal plate 55 to be measured. is provided. Since the base end face of the stationary seal ring 44 is within the detection range of the non-contact sensor 27 , the plate 55 to be measured is shaped so as not to protrude from the base end face of the stationary seal ring 44 .

According to the abnormality detection device 54, similarly to the abnormality detection device 26, when the value detected by the non-contact sensor 27 is out of the range of the threshold value T, that is, the sealing end faces of the two seal rings 44, 47 An alarm is issued when 44a and 47a extend beyond the proper spacing. When the alarm is issued, the equipment is stopped and the hydrostatic non-contact mechanical seal 40 is inspected and repaired.

REFERENCE SIGNS LIST 1 end face contact type mechanical seal 2 non-contact type mechanical seal 4 seal case 4c spring retainer 4d holder 5 stationary seal ring (seal ring provided in the seal case)
6 Rotating shaft 7 Movable sealing ring (sealing ring provided on the rotating shaft)
18 Stationary Seal Ring 18a Seal End Face 18b Seal Ring Main Body 18c Pressing Body 19 Rotating Seal Ring 19a Seal End Face 21 Purge Gas Supply Path 22 Drain Path 23 O-ring 26 Abnormality Detection Device 27 Plate to be Measured 28 Non-Contact Sensor 30 Alarm 40 Non-Contact Type mechanical seal 42 Seal case 42b Spring retainer 42c Holder 44 Stationary seal ring 44 Seal end face 45 Rotating shaft 47 Rotating seal ring 47a Seal end face 54 Abnormality detection device 55 Plate to be measured A Inside area B Outside area (atmospheric area)
C purge gas region P purge gas T threshold

Claims (3)

A seal case having a spring retainer hanging down from an end on the outside of the machine and a retainer extending from the inner periphery thereof toward the inside of the machine, a stationary seal ring axially movably held by the retainer, and a stationary seal. A shaft seal device having a non-contact type mechanical seal comprising a rotary seal ring fixed to a rotary shaft so as to face the ring and rotating the two seal rings relative to each other in a non-contact state,
An abnormality detection device includes a plate to be measured provided on the base end surface of the stationary seal ring, a non-contact type sensor provided on the spring retainer for measuring the distance between the plate to be measured, and the non-contact type and an alarm that issues an alarm when the value detected by the sensor is out of the threshold range,
The non-contact type mechanical seal is disposed on the outside area side of the machine, and on the inside area side of the machine, the seal ring provided on the seal case and the seal ring provided on the rotary shaft rotate in a contact state relative to each other. 1. A shaft sealing device comprising end face contact type mechanical seals disposed, and a purge gas being supplied to a region defined by both mechanical seals. The stationary seal ring comprises a seal ring body facing the rotary seal ring and a pressing body connected to the seal ring body via an O-ring, and the plate to be measured is provided on the base end face of the pressing body. The seal case is formed with a purge gas supply passage through which the purge gas is supplied toward the stationary seal ring and a drain passage through which the purge gas is discharged from the vicinity of the rotary seal ring. 2. A shaft sealing device according to claim 1. 3. A shaft sealing device according to claim 1 , wherein said plate to be measured is formed integrally with the base end face of said stationary seal ring .

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