JPWO2013187322A1 - Failure predictive mechanical seal system for sealing high temperature sealed fluid - Google Patents

Abstract

Providing a failure-predictive mechanical seal system that can detect abnormalities in the sliding surfaces of the rotating side sealing element and stationary side sealing element without being affected by the surroundings of the sliding part of the rotating side sealing element and stationary side sealing element To do. The mechanical seal is an outside type that seals a high-temperature sealed fluid that tends to leak from the inner periphery to the outer periphery of the sliding surface of the rotating side sealing element and the stationary side sealing element, The stationary side sealing element is disposed outside the stuffing box, and a cooling jacket is provided between the inner periphery of the housing and the outer periphery of the rotary shaft so as to prevent the high temperature sealed fluid from circulating to the sliding surface. A temperature detecting means for detecting the temperature of the moving surface and the temperature of the sealed fluid on the inner periphery of the sliding surface is provided.

Description

  The present invention relates to a shaft seal device in which a liquid to be sealed used in a hot water pump and a hot oil pump such as a boiler feed water pump and a condensate pump in a thermal power plant is high temperature, and in particular, a mechanical seal system capable of predicting a failure. About.

  As a device that detects a change in characteristics during operation of a mechanical seal, for example, a temperature change of a sliding portion in real time, a device as shown in FIG. For example, refer to Patent Documents 1, 2, 3, and 4.)

  The temperature detection device for a mechanical seal according to the prior art 1 shown in FIG. 3 has a form of an inside type (a type of sealing a fluid that leaks from the outer periphery of the sliding surface toward the inner periphery) as a contact type mechanical seal. A rotary side sealing element 72 provided on the rotary shaft 70 side for driving a pump impeller (not shown) on the inside of the machine via a packing 71 so as to be rotatable integrally with the rotary shaft 70, and a pump A stationary sealing element 75 provided in a non-rotating state and axially movable in a seal cover 74 fixed to the housing 73 of the housing 73 urges the stationary sealing element 75 in the axial direction (not shown). Therefore, the two end surfaces face each other closely. That is, in this contact-type mechanical seal, high-temperature and high-pressure liquid inside the machine (inside the pump) passes from the outer periphery of the rotary shaft 70 to the outside of the machine at the sliding part S of the rotary side sealing element 72 and the stationary side sealing element 75. It is intended to prevent leakage to And in order to detect the temperature change of the sliding part S in real time, the thermocouple 76 is embed | buried near the sliding part S of the stationary side sealing element 75, and the temperature change of the sliding part S is detected now. Yes.

  However, this type of inside-type contact mechanical seal, when used as a shaft sealing means for hot water pumps and hot oil pumps such as boiler feed pumps and condensate pumps, the liquid to be sealed is high temperature and high pressure. The component may be deformed due to pressure, or the heat generated in the sliding part S or the high temperature liquid to be sealed may cause the component to be thermally deformed or deteriorated, resulting in unstable sealing performance. There is a risk. Therefore, conventionally, as shown in FIG. 4, a part of the liquid to be sealed flowing from the inside of the machine and filling the space 57 on the outer peripheral side of the mechanical seal is formed on the sleeve 51 and integrated with the rotary shaft 50. The partial impeller 58 that rotates at the same time is sent from the seal fluid outlet 59 of the seal cover 54 to the cooler 61 through the flushing pipe 60 and cooled there, and then cooled through the flushing pipe 62 and the seal fluid inlet 63 of the seal cover 54. Thus, the mechanical seal is cooled by the circulation of the liquid to be sealed and the circulation of the liquid to be sealed (hereinafter referred to as “Prior Art 2”, for example, see Patent Document 5).

  On the other hand, the present applicant has arranged a sealing element outside the stuffing box for the purpose of providing a no-flushing and no-cooler mechanical seal in a mechanical seal having a high temperature to be sealed. (Hereinafter referred to as “Prior Art 3”, see Patent Document 6).

However, when the temperature detection device of the prior art 1 shown in FIG. 3 is attached to a mechanical seal in which the liquid to be sealed of the prior art 2 shown in FIG. 4 is high temperature and high pressure, there are the following problems.
(1) The temperature of the sliding part of the rotating side sealing element and the stationary side sealing element is the sum of the temperature of the liquid to be sealed, the cooling effect by flushing, and the heat generated by friction of the sliding part. Even if the temperature of the part is detected, the abnormality of the sliding part of the mechanical seal cannot be determined. That is, even when the temperature of the sliding part is high, the temperature of the liquid to be sealed may increase or the cooling effect may decrease due to flushing. It may be due to a decrease in the temperature of the target liquid or an increase in the cooling effect due to flushing, and it cannot be generally determined that the sliding portion is abnormal.
(2) In order to reduce the influence of the temperature change of the liquid to be sealed and the fluctuation of the cooling effect due to flushing, a temperature detection device is inserted in the gap between the rotating side sealing element and stationary side sealing element and the outer peripheral surface of the rotating shaft. However, it is difficult to install the temperature detection device without impeding the operability of the rotary side sealing element and the stationary side sealing element, and even if the temperature detection device can be installed, the rotating windage heat generated on the rotary shaft Therefore, it is difficult to detect a temperature change due to heat generation of the sliding part.

  In addition, the mechanical seal of the prior art 3 only provides a no-flushing and no-cooler mechanical seal, and it is not assumed that a failure is detected by detecting an abnormality of the sliding portion of the sealing element. Therefore, the technical knowledge for judging the abnormality of the sliding part has not been disclosed or suggested.

Japanese Patent Laid-Open No. 2-199374 Japanese Utility Model Publication No. 1-29326 Japanese Utility Model Publication No. 61-46288 JP 60-39504 A JP 2002-98237 A International Publication No. 2011/036917

  The present invention is a mechanical seal in which a liquid to be sealed used in a hot water pump and a hot oil pump such as a boiler feed water pump or a condensate pump in a thermal power plant is a high temperature, and a rotating side sealing element and a stationary side sealing element It is an object of the present invention to provide a failure prediction type mechanical seal system capable of detecting an abnormality of the sliding surfaces of the rotating side sealing element and the stationary side sealing element without being influenced by the surroundings of the sliding portion.

In order to achieve the above object, a failure predictive mechanical seal system for sealing a high-temperature sealed fluid according to the present invention is firstly attached to a shaft seal formed between a housing and a rotating shaft, and the housing and the rotating In a mechanical seal having a rotating side sealing element and a stationary side sealing element that seals between the shafts,
The mechanical seal is an outside type that seals a high temperature sealed fluid that tends to leak from the inner periphery to the outer periphery of the sliding surface of the rotating side sealing element and the stationary side sealing element,
The rotating side sealing element and the stationary side sealing element are arranged outside a stuffing box;
A cooling jacket is provided between the inner circumference of the housing and the outer circumference of the rotary shaft so as to prevent circulation of the hot sealed fluid to the sliding surface;
A temperature detecting means for detecting the temperature of the sliding surface and the temperature of the sealed fluid on the inner periphery of the sliding surface is provided.
According to this feature, the mechanical seal that seals the high temperature sealing fluid with no flushing and no cooler is used to rotate without being affected by the surroundings of the sliding part of the rotating side sealing element and the stationary side sealing element. It is possible to provide a failure prediction type mechanical seal system capable of detecting an abnormality of a mechanical seal such as an abnormality of a sliding surface of a side sealing element and a stationary side sealing element and an abnormality of a cooling jacket.

The failure prediction type mechanical seal system for sealing a high temperature sealing fluid according to the present invention is secondly characterized in that, in the first feature, the temperature detecting means is mounted in the vicinity of the sliding surface of the stationary side sealing element. A thermocouple, a lead wire led out of the thermocouple from the thermocouple, and a temperature indicator.
According to this feature, the temperature of the sliding surfaces of the rotating side sealing element and the stationary side sealing element and the temperature of the sealed fluid on the inner periphery of the sliding surface can be reliably detected.

The failure prediction type mechanical seal system for sealing a high-temperature sealed fluid according to the present invention is thirdly characterized in that, in the first or second feature, the rotary side sealing element and the stationary member arranged on the outside of the machine from the cooling jacket. In the side sealing element, the stationary side sealing element is disposed inside the machine, and the rotating side sealing element is arranged outside the machine. A large part of the outer peripheral side of the stationary side sealing element faces the atmosphere outside the machine, The clearance γ between the outer periphery of the rotating shaft and the outer periphery of the cooling jacket is set larger than the clearance β between the outer periphery of the rotating shaft and the inner periphery of the cooling jacket so that the sealed fluid can easily flow. It is characterized by being arranged to rotate in the outside atmosphere.
According to this feature, the temperature of the sliding surface of the rotating side sealing element and the stationary side sealing element in the normal state is substantially equal to the temperature of the sealed fluid on the inner periphery of the sliding surface, and is stable. By detecting the temperature of the surface, the temperature of the sealed fluid on the inner periphery of the sliding surface can also be detected.

According to a fourth aspect of the mechanical seal of the present invention, in any one of the first to third features, the cooling jacket has a cooling water accommodation space communicating with a cooling water supply / drain hole provided in the stuffing box. The outer periphery of the housing is hermetically attached to the inner periphery of the housing via O-rings on both outer circumferences. It is characterized in that it is set larger than the gap β.
According to this feature, the cooling effect by the cooling jacket can be maximized by reducing the gap between the outer periphery of the rotating shaft and the inner circumference of the cooling jacket to a minimum and minimizing the volume of the sealing fluid interposed in the gap. . Even if the rotating shaft swings and the outer periphery of the rotating shaft comes into contact with the inner periphery of the cooling jacket, the shock is absorbed by the cushioning action of the O-ring, so that the contact surface pressure can be reduced and galling caused by contact sliding In addition, it is possible to prevent wear of the two and to maintain the initial gap over a long period of time and to increase the cooling effect of the cooling jacket.

The present invention has the following excellent effects.
(1) In a mechanical seal that is mounted on a shaft seal formed between a housing and a rotating shaft, and includes a rotating side sealing element and a stationary side sealing element that seals between the housing and the rotating shaft, The mechanical seal is an outside type that seals a high-temperature sealed fluid that tends to leak from the inner periphery to the outer periphery of the sliding surface of the rotating side sealing element and the stationary side sealing element, The sealing element and the stationary side sealing element are disposed outside the stuffing box, and are disposed between the inner periphery of the housing and the outer periphery of the rotating shaft so as to prevent the hot sealed fluid from circulating to the sliding surface. A cooling jacket is provided, and temperature detecting means for detecting the temperature of the sliding surface and the temperature of the fluid to be sealed on the inner periphery of the sliding surface is provided. By utilizing the characteristics of the mechanical seal that seals the high temperature sealing fluid with the seal, the sliding of the rotating side sealing element and the stationary side sealing element is not affected by the surroundings of the sliding part of the rotating side sealing element and the stationary side sealing element. It is possible to provide a failure prediction type mechanical seal system capable of detecting a mechanical seal abnormality such as a moving surface abnormality and a cooling jacket abnormality.

(2) The temperature detecting means includes a thermocouple mounted in the vicinity of the sliding surface of the stationary side sealing element, a lead wire led out from the thermocouple to the outside of the machine, and a temperature indicator. The temperature of the sliding surfaces of the side sealing element and the stationary side sealing element and the temperature of the sealed fluid on the inner periphery of the sliding surface can be reliably detected.

(3) In the rotating side sealing element and the stationary side sealing element arranged on the outer side of the cooling jacket, the stationary side sealing element is arranged on the inner side of the machine, and the rotating side sealing element is arranged on the outer side of the machine. Most of the outer peripheral side of the sealing element faces the outside atmosphere, and a gap γ between the inner periphery and the outer periphery of the rotating shaft is formed between the outer periphery of the rotating shaft and the inner periphery of the cooling jacket so that the sealed fluid can easily flow. The rotation side, which is set larger than the gap β, and is configured to rotate in the atmosphere outside the machine, the rotation side consisting of the rotation side sealing element and the collar, etc. The temperature of the sliding surface is almost equal to the temperature of the sealed fluid on the inner periphery of the sliding surface and is stable, and the temperature of the sealed fluid on the inner periphery of the sliding surface is detected by detecting the temperature of the sliding surface. Can also detect .

(4) The cooling jacket has a cooling water accommodation space communicating with the cooling water supply / drain hole provided in the stuffing box in the center, and is attached to the inner circumference of the housing in a sealed manner via O-rings on both outer circumferences. The clearance between the outer periphery of the cooling jacket and the inner periphery of the housing is set to be larger than the clearance between the outer periphery of the rotating shaft and the inner periphery of the cooling jacket, thereby narrowing the clearance between the outer periphery of the rotating shaft and the inner periphery of the cooling jacket to a minimum. By minimizing the volume of the sealing fluid interposed in the gap, the cooling effect by the cooling jacket can be maximized. Even if the rotating shaft swings and the outer periphery of the rotating shaft comes into contact with the inner periphery of the cooling jacket, the shock is absorbed by the cushioning action of the O-ring, so that the contact surface pressure can be reduced and galling caused by contact sliding. In addition, it is possible to prevent wear of the two and to maintain the initial gap over a long period of time and to increase the cooling effect of the cooling jacket.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front sectional view showing an entire failure prediction type mechanical seal system that seals a high-temperature sealed fluid according to an embodiment of the present invention. It is a principal part enlarged view which expands and shows the principal part of FIG. It is front sectional drawing which shows the prior art 1. FIG. It is front sectional drawing which shows the prior art 2. FIG.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment for carrying out a failure prediction type mechanical seal system for sealing a high-temperature sealed fluid according to the present invention will be described in detail with reference to the drawings, but the present invention is not construed as being limited thereto. Various changes, modifications, and improvements can be made based on the knowledge of those skilled in the art without departing from the scope of the invention.

  A failure prediction type mechanical seal system for sealing a high temperature sealing fluid according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

The mechanical seal 1 includes a housing 2 for a shaft seal in a hot water pump and a hot oil pump such as a boiler feed water pump and a condensate pump of a thermal power plant, and a pump for handling a high temperature liquid exceeding 200 ° C. The mechanical seal 1 is mounted in a cartridge type between the housing 2 and the rotary shaft 3 for sealing between the rotary shafts 3 fitted in the shaft fitting holes 10.
In FIG. 1, the left side is the aircraft inner side, and the right side is the aircraft outer side (atmosphere side).

A rotation shaft 3 is provided through the shaft fitting hole 10 of the housing 2. A seal cover 5 is attached to the side surface 4 on the outside of the machine 2 around the shaft fitting hole 10 by means of fixing means such as bolts 6, and the space inside the seal cover 5 and outside the rotary shaft 3 is mechanically attached. A stationary side sealing element (hereinafter referred to as “seal ring”) 7 and a rotary side sealing element (hereinafter referred to as “mating ring”) 8 constituting the seal 1 are arranged.
Further, a stuffing box 9 having an enlarged diameter is formed near the outside of the shaft fitting hole 10 of the housing 2, and a cooling jacket 11 described later is disposed in the stuffing box 9. Thus, the mating ring 8 and the seal ring 7 are provided outside the stuffing box 9, that is, outside the machine. For this reason, the capacity | capacitance of the cooling jacket 11 can be enlarged enough, and the sliding surface of the mating ring 8 and the seal ring 7 will be located in the atmosphere side, and sliding heat_generation | fever may accumulate. Absent.

The mechanical seal 1 is formed in an outside shape that seals the sealed fluid 12 that is about to leak from the inner periphery to the outer periphery of the sliding surface S between the seal ring 7 and the mating ring 8.
The seal cover 5 has an annular shape so as to surround the rotary shaft 3, and an axial hole is formed in the seal cover 5. As shown in FIG. 2, the inner peripheral surface forming the hole of the seal cover 5 has a fitting surface 5C, a space (hereinafter referred to as “annular groove”) 5G, and an aperture in order from the inner side to the outer side. Surface 5F is formed. Among these, the annular groove 5G is formed between the fitting surface 5C and the diaphragm surface 5F so as to have a larger diameter than the outer diameter of the fitting surface 5C. Further, the axial width of the annular groove 5G is made large so that most of the seal ring 7 and the mating ring 8 are present in the inner periphery of the annular groove 5G. Further, the diaphragm surface 5F is formed on the inner periphery of the front surface (near the machine exterior) of the seal cover 5 in order to increase the axial width of the annular groove 5G.
Further, a positioning portion 5T is provided on the front surface of the seal cover 5 so as to surround the hole. This positioning portion 5T is formed with a convex end in the axial direction in order to provide a positioning groove 5B on the outer periphery.

  The moving surface 7D of the seal ring 7 is fitted to the fitting surface 5C of the seal cover 5 so as to be movable in the axial direction. The moving surface 7D of the seal ring 7 is formed with a first seal groove 7B for O-ring that seals between the fitting surface 5C. As for this 1st seal groove 7B, in order to make an adhesion | attachment easy to wash | clean, for example, the machine inside has formed the space | interval large with respect to 5 C of fitting surfaces. Then, an O-ring 13A is attached to the first seal groove 7B. The material of the O-ring 13A is fluorine rubber, nitrile rubber, H-NBR, EPDM, perfluoroelastomer, or the like.

  Further, the seal ring 7 forms a sliding seal surface 7A on the end surface opposite to the first seal groove 7B. Further, the outer peripheral side of the seal ring 7 forms a flange 7F. A guide groove 7G is formed in the flange 7F. Further, a fixing pin 14 is press-fitted and attached to a fitting hole provided in a side surface of the annular groove 5G of the seal cover 5. The guide groove 7G is movably fitted to the fixed pin 14, and the seal ring 7 is moved in the axial direction by the fixed pin 14, but is locked in the rotational direction. Further, as shown in FIG. 1, the seal cover 5 facing the flange 7F is provided with a plurality of hole-shaped spring seats 5H arranged in the circumferential direction. Coil springs 15 provided at equal intervals along the peripheral surface are seated on the spring seat 5H and elastically press the seal ring 7.

The seal ring 7 has a balance between the projected area A1 in the axial direction of the sliding seal surface 7A of the seal ring 7 and the projected area A2 in the axial direction that receives a sealed fluid pressure acting as a moving force in the axial direction with respect to the seal ring 7. The ratio A2 / A1 is formed in a balanced form in which the ratio is set to 1 or less, and the load on the sliding surface S due to the sealing fluid pressure is reduced.
The seal ring 7 is made of SiC by a special conversion method (partially converting the carbon surface to SiC, reinforcing the surface strength, and combining both the wear resistance of SiC and the self-lubricating property of carbon). Yes. It may also be made of diamond-coated SiC.

  On the other hand, the collar 20 is provided with a fitting peripheral surface 20C and a second seal groove 20B on the inner periphery. The fitting peripheral surface 20C is fitted to the outer peripheral surface 3A of the rotating shaft 3, and the fitting surfaces of both components are sealed by the O-ring 13C fitted to the second seal groove 20B. Further, the tip end portion of the set screw 21 screwed into the collar 20 is fixed to the outer peripheral surface 3 </ b> A of the rotating shaft 3 to fix the collar 20 to the rotating shaft 3. Then, an outer periphery inside the mating ring 8 in the collar 20 is formed on the coupling surface 20D. A holding surface 20S is provided on the annular stepped surface provided on the outer peripheral side from the coupling surface 20D. Furthermore, the drive pin 22 is press-fitted into the fitting hole provided in the holding surface 20S of the collar 20 and attached. Thus, since it is not necessary to provide a sleeve on the outer periphery of the shaft, the seal size can be reduced by the thickness of the sleeve, the sliding surface peripheral speed can be reduced, and the sliding surface load can be reduced.

Further, a sliding seal surface 8A is formed at one end of the mating ring 8 as shown in FIG. The sliding seal surface 8A is formed so as to be able to slide in close contact with the sliding seal surface 7A of the seal ring 7. Further, a stepped surface 8B for sealing is formed on the inner peripheral surface 8C of the mating ring 8. An O-ring 13B is attached to the stepped surface 8B to seal between the fitting surfaces of the inner peripheral surface 8C of the mating ring 8 and the coupling surface 20D of the collar 20. Further, a pin recess 8G is formed on the joining surface 8E at the end of the mating ring 8 on the outside of the machine. The drive pin 22 screwed into the fitting hole of the collar 20 is inserted into the pin recess 8G, and the parts of the mating ring 8 and the collar 20 are locked to each other so as not to move in the circumferential direction. Then, the rotational force of the collar 20 is transmitted to the mating ring 8 by the drive pin 22. As described above, the rotating side including the mating ring 8 and the collar 20 is arranged so as to rotate in the outside atmosphere. For this reason, the rotating side is forcibly air-cooled by the atmosphere. Further, since the portion on the rotating side in contact with the sealed fluid is only the sealing fluid side end surface of the mating ring 8 and the collar 20, the contact area with the high temperature sealed fluid is small, and heat is generated due to rotational friction at high speed rotation. Few.
The mating ring 8 is manufactured from a material such as SiC by a special conversion method, or ceramics such as SiC or a cemented carbide by another manufacturing method. It may also be made of diamond-coated SiC.
At least one member of the seal ring 7 or mating ring 8 is made of SiC by special conversion method so as to have lubricity and wear resistance, thereby preventing the change of the sliding surface state during long-term operation. Yes.

In the range where the diameter of the rotary shaft 3 is 100 mm or less, the width of the sliding surface S between the mating ring 8 and the seal ring 7 is set to 1.5 mm or less, and the balance ratio A2 / A1 is set to 0.7 or less. Is good.
In the range where the diameter of the rotating shaft 3 exceeds 100 mm and is 200 mm or less, the width of the sliding surface S between the mating ring 8 and the seal ring 7 is 2.0 mm or less, and the balance ratio A2 / A1 is 0.7. The following should be set. For this reason, the hydraulic pressure working area is minimized, and the pressing force due to the fluid pressure is minimized, so the heat generation is designed to be minimized.
Furthermore, it is desirable that the gap between the inner periphery of the seal ring 7 and the outer periphery of the rotating shaft 3A is 2.5 mm or more regardless of the diameter of the rotating shaft 3 described above. As described above, the clearance between the inner periphery of the seal ring 7 and the outer periphery of the rotary shaft 3A is made large so that the cold sealed fluid cooled by the cooling jacket described later flows, thereby sliding by sliding heat generation. Heat storage near the surface can be prevented and temperature rise can be minimized.

  The seal cover 5 is provided with a gasket 24 between the housing 2 and a seal between the housing 2 and the seal cover 5. The gasket 24 is made of a material such as rubber, resin, or metal coated with rubber.

  Further, the annular groove 5G of the seal cover 5 is preferably formed in a large dimension in the axial direction so as to cover most of the seal ring 7 and the mating ring 8. The side surface on the machine inner side of the annular groove 5G is formed so as to be close to the first seal groove 7B of the seal ring 7. Furthermore, the side surface of the mating ring 8 of the annular groove 5G reaches the middle of the mating ring 8. Moreover, it is good to form the diameter of the outer peripheral surface of the annular groove 5G large.

As shown in FIG. 1, the seal cover 5 and the collar 20 are assembled at the same time as positioning by fitting the convex portion 27 of the set plate 25 attached to the collar 20 via a bolt 26 into the positioning groove 5 </ b> B of the seal cover 5. . Then, when the mating ring 8 is positioned, the set screw 21 is screwed onto the rotary shaft 3 and stopped, and the collar 20 is fixed to the rotary shaft 3.
The set plate 25 is formed in a cross-sectional shape as shown in FIG. 1, and is mounted on the circumferential surface of the collar 20 in a three-dimensional arrangement. The set plate 25 may be removed after assembly.

  On the other hand, a ring-shaped cooling jacket 11 is provided between the inner periphery of the housing 2 and the outer periphery of the rotary shaft 3 in the stuffing box 9 formed near the outside of the shaft fitting hole 10 of the housing 2. . The cooling jacket 11 has a cooling water accommodation space 30 that communicates with a cooling water supply hole 28 provided immediately below the circumferential position of the stuffing box 9 and a cooling water drain hole 29 provided immediately above the central portion. And O-ring grooves 32 and 32 for mounting O-rings 31 and 31 respectively are provided on both outer circumferences. The thickness of the O-ring 31 is set larger than the depth of the O-ring groove 32. A plurality of fins 33 are provided inside the cooling water storage space 30 of the cooling jacket 11 near the outer periphery of the rotating shaft.

  The cooling jacket 11 is hermetically mounted on the inner periphery of the housing 2 via an O-ring 31, but is mounted so as to have a gap α between the outer periphery of the cooling jacket 11 and the inner periphery of the housing 2. The clearance α between the outer periphery of the cooling jacket 11 and the inner periphery of the housing 2 is set larger than the clearance β between the outer periphery of the rotary shaft 3 and the inner periphery of the cooling jacket 11. The clearance β between the outer periphery of the rotary shaft 3 and the inner periphery of the cooling jacket 11 is set to 0.1 to 0.2 mm.

  As described above, the cooling jacket 11 is provided in the stuffing box 9, the gap between the outer periphery of the rotary shaft 3 and the inner circumference of the cooling jacket 11 is minimized, and the volume of the high-temperature sealed fluid interposed in the gap is minimized. By doing so, the cooling effect by the cooling jacket 11 can be maximized. Further, the high temperature sealed fluid is prevented from circulating around the sliding surfaces of the seal ring 7 and the mating ring 8, the temperature of the sealed fluid around the sliding surface is kept constant at a low temperature, and the sliding The thermal effect on the moving surface is minimized. Furthermore, the clearance α between the outer periphery of the cooling jacket 11 and the inner periphery of the housing 2 is set to be larger than the clearance β between the outer periphery of the rotation shaft 3 and the inner periphery of the cooling jacket 11, so that the rotation shaft 3 is swung and rotated by any chance. Even if the outer periphery of the shaft 3A contacts the inner periphery of the cooling jacket 11, the shock is absorbed by the buffering action by the elasticity of the O-ring, so that the contact surface pressure can be reduced, and galling due to contact sliding and wear of both can be prevented. Over the period, the initial gap can be maintained and the cooling effect of the cooling jacket 11 can be increased.

  Next, temperature detection means for detecting the temperature of the sliding surface of the seal ring 7 and the mating ring 8 and the temperature of the sealed fluid on the inner periphery of the sliding surface will be described.

  The temperature detection means 40 includes a thermocouple 41 mounted near the sliding surface 7A of the seal ring 7, a lead wire 42 led out from the thermocouple 41 to the outside of the machine, and a temperature indicator 43. As shown in FIG. 2, the thermocouple 41 may be embedded in the vicinity of the sliding surface 7A in the seal ring 7, or may be fixed by welding or the like in the vicinity of the sliding surface 7A on the surface of the seal ring 7. Good. The lead wire 42 led out from the thermocouple 41 to the outside of the machine can be easily wired by leading out to the outside of the machine via the annular groove 5G of the seal cover 5.

  By the way, in the seal ring 7 and the mating ring 8 arranged outside the cooling jacket 11, the seal ring 7 is arranged inside the machine, and the mating ring 8 is arranged outside the machine. The portion faces the machine exterior atmosphere, that is, the annular groove 5G, and the clearance γ between the inner periphery and the outer periphery of the rotary shaft 3 is such that the low-temperature sealed fluid cooled by the cooling jacket 11 flows easily. 3 is set to be larger than the gap β between the outer periphery of the cooling jacket 11 and the inner periphery of the cooling jacket 11, and the rotating side including the mating ring 8 and the collar 20 is arranged so as to rotate in the outside atmosphere. The temperature of the sliding surface S is substantially equal to the temperature of the sealed fluid on the inner periphery of the sliding surface S and is stable. Therefore, detecting the temperature of the sliding surface S is the same as detecting the temperature of the sealed fluid on the inner periphery of the sliding surface S.

If the temperature of the sliding surface S and the temperature of the sealed fluid on the inner periphery of the sliding surface S are stable, it is confirmed that the high temperature fluid from the back side of the stuffing box 9 does not flow into the sliding surface S. This means that the sealing performance of the mechanical seal is good.
On the contrary, if the sealing performance of the mechanical seal is lowered, the high-temperature fluid leaked from the mechanical seal flows into the sliding surface S, and the temperature of the sliding surface S, that is, the detection temperature rises.
Furthermore, when the detected temperature is stable and high, an abnormality of the cooling jacket 11 is considered.
Furthermore, when the detected temperature rises little by little, the life of the mechanical seal can be considered.
Thus, by monitoring the temperature of the sliding surfaces of the seal ring 7 and the mating ring 8 and the temperature of the sealed fluid on the inner periphery of the sliding surface, it is possible to know the abnormality of the mechanical seal.

  The embodiments of the present invention have been described above with reference to the drawings. However, the specific configuration is not limited to the embodiments, and even if there are changes or additions without departing from the gist of the present invention. It is included in the present invention.

  For example, in the above-described embodiment, the thermocouple 41 is shown as the temperature sensor, but the present invention is not limited to this. For example, a thermistor, a platinum resistance thermometer, or a radiation thermometer may be used.

  Further, for example, in the above-described embodiment, the thermocouple 41 is embedded in the vicinity of the sliding surface 7A in the seal ring 7 or fixed by welding or the like in the vicinity of the sliding surface 7A on the surface of the seal ring 7. However, the present invention is not limited to this. For example, a hole may be provided in the seal ring 7 and the thermocouple 41 may be inserted into the hole.

  Further, for example, in the above-described embodiment, the example in which the lead wire 42 led out from the thermocouple 41 to the outside of the machine is led out to the outside of the machine via the annular groove 5G of the seal cover 5 has been described. For example, a lead-out hole may be provided in the seal cover 5 and lead out to the outside of the machine.

1 Mechanical seal
2 Housing
3 Rotating shaft
4 Outside side of housing
5 Seal cover
6 bolts
7 Static side sealing element (seal ring)
8 Rotating side sealing element (Mating ring)
9 Staffing box
10 Shaft fitting hole
11 Cooling jacket
12 Sealed fluid
13 O-ring
14 Fixing pin
15 Coil spring
20 colors
21 set screw
22 Drive pin
24 Gasket
25 set plates
26 volts
27 Convex
28 Cooling water supply hole
29 Cooling water drain hole
30 Cooling water storage space
31 O-ring
32 O-ring groove
33 fins
40 Temperature detection means
41 Thermocouple
42 Lead wire
43 Temperature indicator

Claims (4)

In a mechanical seal that is attached to a shaft seal formed between a housing and a rotating shaft, and includes a rotating side sealing element and a stationary side sealing element that seals between the housing and the rotating shaft.
The mechanical seal is an outside type that seals a high temperature sealed fluid that tends to leak from the inner periphery to the outer periphery of the sliding surface of the rotating side sealing element and the stationary side sealing element,
The rotating side sealing element and the stationary side sealing element are arranged outside a stuffing box;
A cooling jacket is provided between the inner circumference of the housing and the outer circumference of the rotary shaft so as to prevent circulation of the hot sealed fluid to the sliding surface;
A failure prediction type mechanical seal system for sealing a high temperature sealing fluid, characterized in that temperature detection means for detecting the temperature of the sliding surface and the temperature of the sealed fluid on the inner periphery of the sliding surface is provided.   The temperature detecting means includes a thermocouple mounted in the vicinity of the sliding surface of the stationary side sealing element, a lead wire led out from the thermocouple to the outside of the machine, and a temperature indicator. A failure prediction type mechanical seal system for sealing a high temperature sealing fluid according to claim 1.   In the rotating side sealing element and the stationary side sealing element arranged on the outer side of the cooling jacket, the stationary side sealing element is arranged on the inner side of the machine, and the rotating side sealing element is arranged on the outer side of the machine. Most of the outer peripheral side faces the outside atmosphere, and the clearance γ between the inner periphery and the outer periphery of the rotating shaft is larger than the clearance β between the outer periphery of the rotating shaft and the inner periphery of the cooling jacket so that the fluid to be sealed flows easily. The failure to seal the high temperature sealing fluid according to claim 1 or 2, characterized in that it is set to be large and the rotating side composed of the rotating side sealing element and the collar is arranged to rotate in the outside atmosphere. Predictive mechanical seal system.   The cooling jacket has a cooling water accommodation space communicating with a cooling water supply / drainage hole provided in the stuffing box at the center, and is hermetically attached to the inner periphery of the housing on both outer circumferences via O-rings. The clearance α between the outer periphery of the cooling jacket and the inner periphery of the housing is set to be larger than the clearance β between the outer periphery of the rotating shaft and the inner periphery of the cooling jacket. Failure-predictive mechanical seal system that seals high-temperature sealed fluid.

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