JP5530738B2 - mechanical seal - Google Patents

Description

  The present invention relates to a mechanical seal using a SiC sliding material as a material for a stationary seal ring.

  SiC (silicon carbide) has excellent properties as a sliding material for mechanical seals and bearings, but the friction coefficient is high and abnormal wear occurs in situations where sufficient lubricating liquid does not flow into the sliding part or in dry conditions. There is also a disadvantage that it is easy to invite. Therefore, as countermeasures, contrivances such as hydrocutting and grooving of the SiC sliding material, quenching and the like from the back of the seal have been taken.

  In Patent Document 1, one or both of the two sealing rings 1 and 3 that are in relative sliding contact with each other are carbonized in which independent pores having an average pore diameter of 10 to 40 μm are uniformly arranged and the porosity is 3 to 10%. A mechanical seal having a sealing ring made of silicon sintered material is disclosed. Thereby, even when the mating seal ring is made of a hard material such as silicon carbide or a soft material such as carbon, the lubricity between the mating seal ring can be greatly improved, Regardless of the sealing conditions, it contributes to the realization of a mechanical seal that is extremely excellent in durability such as wear resistance and sealing performance.

  In Patent Document 2, the crystal grain average diameter of the sintered silicon carbide part is 0.010 to 0.030 mm, pores are formed between the crystal grain boundaries, and the pore size is 0.001. A mechanical seal with a stationary seal ring formed in the range of 0.020 and having a porosity of 3 to 10% by volume is disclosed. Thus, it is described that a static seal ring as a silicon carbide sintered part which is excellent in strength, excellent in wear resistance, corrosion resistance and high temperature resistance and suitable for a mechanical seal can be obtained.

  In Patent Document 3, an α-SiC powder having an average particle diameter of 0.1 or more and 10 μm or less, a β-SiC powder having an average particle diameter of 0.1 or more and 10 μm or less, and vapor phase synthesis by a plasma CVD method. A mechanical seal having a sealing ring formed by mixing SiC ultrafine powder with an average particle diameter of less than 0.1 μm at a desired ratio to obtain SiC mixed powder and heating and sintering the SiC mixed powder is disclosed. ing. Thus, it is described that the specific resistance value of the silicon carbide sintered body can be provided which can reduce the specific resistance value of the silicon carbide sintered body and can control the specific resistance over a wide range.

  As described above, the mechanical seal in which the wear resistance of the sealing ring is improved by using the SiC sliding material is a well-known technique. However, diversification of the fluid to be sealed and use under conditions in which the fluid to be sealed does not go into the sliding portion, it may be difficult to fully exhibit the performance as a seal ring for mechanical seal made of SiC sliding material. As described above, there are measures to perform hydrocutting and grooving, but there are chronic problems such as difficulty in processing and cost and labor.

On the other hand, a mechanical seal having a sealing ring made of a material in which a self-lubricating material is blended with a SiC sliding material, such as impregnation with a low friction material such as carbon, graphite, BN, MoS2, or a fluororesin, has been developed. Since the production is difficult and the cost is very high, the intended use is limited. As described above, in order to eliminate or suppress the problem that the friction coefficient is increased and the wear is accelerated depending on use conditions, the seal ring made of SiC sliding material having various advantages is further improved. There was room left.
Japanese Patent No. 3517711 JP 2002-338368 A JP-A-9-255428

  The object of the present invention is to have a stationary seal ring using SiC sliding material by conducting earnest research, and in a severe environment such as a situation where sufficient lubricating liquid does not flow into the sliding part and a dry situation Even below, it is in the point which implement | achieves and provides the mechanical seal which is excellent in durability and reliability, suppressing or canceling the disadvantage that a friction coefficient becomes high.

The invention according to claim 1 includes a rotary seal ring 2 supported on the rotary shaft 1 so as not to be relatively rotatable, a stationary seal ring 4 supported on the housing 3 so as not to be relatively rotatable, and a seal surface 2 a of the rotary seal ring 2. And a sealing surface 4a of the stationary seal ring 4 are pressed against each other in the direction of the axis X of the rotary shaft to form a seal portion S, and a mechanical seal comprising:
The stationary seal ring 4 is made of a SiC sliding material,
Water at a temperature of 30 ° C. and a pressure of 2.5 MPa is introduced from the outer peripheral surface of the annular body formed by processing the stationary sealing ring 4 into a predetermined standard size of outer diameter × inner diameter × thickness of φ54 mm × φ40 mm × 6 mm. penetrates and penetration leakage amount per coming out unit time bleeding from the inner peripheral surface F, or the stationary seal penetration leakage per unit time to come oozed from the inner peripheral surface penetrates the inside from the outer peripheral surface of the ring 4 A conversion value F in which the amount is adjusted to the predetermined standard dimension is as follows :
0.01ml / 24hr ≦ F ≦ 500ml / 1hr
And is formed of a SiC sliding material having self-penetration property defined in
The stationary seal ring 4 is formed with an intake port 14 for taking in the sealing liquid f supplied via the housing 3 and an internal flow path 15 subsequent thereto. .

  According to a second aspect of the present invention, in the mechanical seal according to the first aspect, the internal flow path 15 penetrates the seal portion S and is closed by the seal surface 2a of the rotary seal ring 2. It is characterized by being.

  The invention according to claim 3 is the mechanical seal according to claim 2, wherein the seal surface 4a of the stationary seal ring 4 is annular with respect to the axis X, and the opening on the seal surface side of the internal channel 15 is provided. The mechanical seal according to claim 2, wherein a side circumferential groove 16 for filling a sealing liquid is formed.

  According to a fourth aspect of the present invention, in the mechanical seal according to the second or third aspect, an outer peripheral groove 17 for filling a sealing liquid including the intake port 14 is formed on the outer peripheral surface 4b of the stationary seal ring 4. It is characterized by that.

  According to a fifth aspect of the present invention, in the mechanical seal according to the first aspect, the internal flow path 15 is formed in a dead end shape whose end is located inside the stationary seal ring 4. It is a feature.

  According to the first aspect of the present invention, as will be described in detail in the section of the embodiment, the sealing liquid is supplied to the SiC sliding material using the internal channel while having sufficient strength and hardness as the SiC sliding material. Can penetrate. Therefore, the wet state can be maintained moderately by the liquid permeation, and the sealing surface (sliding surface) of the stationary sealing ring can always be in a liquid atmosphere. Then, by defining the permeation leakage amount of the annular body formed by processing the stationary sealing ring to a predetermined standard size, there is the convenience that the leakage amount of the sealing ring having a different size depending on the product can be defined directly or in terms of conversion.

Further, since it is formed inside the unit path you supply sealing liquid to the SiC sliding member as the stationary sealing ring supported by the housing, the internal flow of the rotary seal ring which rotates as manufactured SiC sliding member Compared with the case of having a path, there is an advantage that the structure for supplying the sealing liquid supply path is simple and inexpensive.
Then, the sealing liquid penetrates quickly and reaches the sealing portion, and the response time from the start of supplying the sealing liquid to actually reaching the sealing portion compared to the case where the internal flow path is not formed. It is shortened, and the responsiveness that the sealing liquid reaches the seal portion becomes excellent.
As a result, there is a disadvantage that the friction coefficient becomes high even in a severe environment such as a situation in which a sufficient amount of lubricating liquid does not flow into the sliding part or a dry situation while having a stationary sealing ring using a SiC sliding material. Can be suppressed or eliminated, and a mechanical seal excellent in durability and reliability can be provided.

  According to the second aspect of the present invention, since the internal flow path is configured to pass through the stationary sealing ring and closed by the seal portion, the sealing liquid quickly reaches the seal portion, There is an advantage that the responsiveness is improved.

  According to the invention of claim 3, since the side circumferential groove for filling the sealing liquid is provided on the sealing surface of the stationary sealing ring, the speed with which the sealing liquid reaches the entire seal portion becomes faster. There is an advantage that the responsiveness is further improved.

  According to the fourth aspect of the present invention, the outer peripheral groove for filling the sealing liquid formed on the outer peripheral surface of the stationary sealing ring is formed in the stationary sealing ring while the number of liquid passages in the housing is small. The advantage is that the sealing liquid can be supplied to the plurality of internal flow paths smoothly and inexpensively in a well-balanced manner.

  According to the invention of claim 5, since the internal flow path of the stationary seal ring is a dead end, it is allowed to permeate the inside of the SiC sliding material with a sealing fluid having a certain pressure, It becomes possible to make the sealing surface (sliding surface) of the ring a liquid atmosphere. In this case, there is an advantage that the sealing fluid can be supplied to the sealing surface in a uniformly distributed state by permeation.

Sectional drawing of the principal part which shows a mechanical seal and its structure (Example 1) Sectional view showing an experimental device for measuring the permeability of a stationary seal ring FIG. 2 is a cross-sectional view of the test apparatus filled with the test solution. (A) Various characteristic diagrams of a plurality of examples and comparative examples, (b) is a diagram showing a table of porosity and self-permeability of each example The enlarged surface condition of a SiC sliding material is shown, (a) is Example 1, (b) is Example 4. The expansion | swelling surface condition of a SiC sliding material is shown, (a) is the comparative example 1, (b) is the comparative example 2, (c) is the comparative example 4. Block diagram showing a method for manufacturing a sealing ring for a mechanical seal The fragmentary sectional view which shows the principal part of the mechanical seal by Example 2 The fragmentary sectional view which shows the principal part of the mechanical seal by Example 3

  Embodiments of a mechanical seal, a static sealing ring made of SiC, and a manufacturing method thereof according to the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, the mechanical seal M is attached to a rotating seal ring 2 that is externally fitted to the rotating shaft 1 so as to be movable in the direction of the axis X thereof, and rotates together with the rotating shaft 1. The stationary sealing ring 4 is fitted in such a manner that it cannot be rotated relative to the stationary sealing ring 4, and the elastic mechanism 5 for pressing the rotary sealing ring 2 against the stationary sealing ring 4 to form the seal portion S. That is, the mechanical seal M seals the machine interior (process side) P including the space between the housing 3 and the rotary shaft 1 and the machine exterior (atmosphere side) T including the space between the housing 3 and the rotary shaft 1. Examples of the liquid to be sealed (process liquid) include water (industrial water, tap water), chemical liquids, crude oil related liquids, cleaning liquids and the like in plant facilities and the like.

  A fixed support wheel 13 that is pressed and locked to the shaft outer periphery 1a by a shaft screw 9 is externally mounted on the inner side of the rotary shaft 1, and a working wheel 7 is loosely fitted on the outer side of the rotary shaft 1 so as to be movable in the axis X direction. The elastic mechanism 5 is arranged by arranging the coil springs 8 interposed between the fixed support wheel 13 and the working wheel 7 at equal angles around the axis X in a posture along the direction of the axis X. It is configured. The rotary seal ring 2 is press-fitted and held on the distal end side of a holding ring 6 that is externally fitted to the rotary shaft 1 so as to be movable in the direction of the axis X, and the base end shaft portion 6a of the holding ring 6 is a working wheel. 7 is inserted into the through-hole 7a and rotates together with the working wheel 7. An O-ring 12 for sealing is interposed between the holding ring 6 and the rotating shaft 1. Therefore, the urging force of the coil spring 8 acts on the rotary seal ring 2 via the action wheel 7 and the holding ring 6.

  The housing 3 has a stationary sealing ring through two O-rings 10 and 11 so that the stationary sealing ring cannot move to the machine outside T in the direction of the axis X and rotate around the axis X, and the rotation axis. 1 is fitted in a state of being loosely fitted. The rotary seal ring 2 is pressed and urged toward the machine outer side T by the elastic mechanism 5, and therefore, the seal surface 2a which is the side peripheral surface of the machine outside and the seal surface which is the front side circumferential surface of the stationary seal ring 4 inside the machine. 4a is in pressure contact with each other in the direction of the axis X, whereby an annular seal portion S is formed. The rotary seal ring 2 is made of carbon or other material.

  The stationary seal ring 4 is formed of a SiC sliding material having self-penetration. SiC, which is the material of the SiC sliding material, is a normal sintered body, which realizes low density due to the sintering temperature, molding surface pressure, etc., and does not contain a self-lubricating material. It has hardness and strength that satisfy the performance required for the seal M. As shown in FIG. 7, the manufacturing method of this SiC sliding material includes a mixing step a in which SiC powder and methanol are mixed, a granulating step b in which a mixture is spray-dried to create a granulated material, A granulated material obtained by the granulating step b is put into a mold and press-molded to form an annular shaped body, and the shaped body obtained by the forming step c is fired in a predetermined high-temperature argon atmosphere to sinter silicon carbide. And a firing step d for creating a body.

  A silicon carbide sintered body obtained by the above-described manufacturing method, that is, one end surface (one side peripheral surface) or both end surfaces of the silicon carbide sintered body by the firing step d is polished to create a sealing ring for sealing. By passing through the finishing process e, the above-mentioned stationary sealing ring 4 is created. That is, as shown in FIG. 7, by adding a finishing step e for polishing the one end surface of the silicon carbide sintered body by the firing step to the method for manufacturing the sliding material for mechanical seal, the stationary seal ring for mechanical seal is added. Is defined as the manufacturing method. In addition, the manufacturing method of the stationary seal ring for mechanical seals is the concept which encompasses the manufacturing method of the sliding material for mechanical seals.

  A method for manufacturing the stationary seal ring 4 for the mechanical seal will be described in detail. First, the mixing step a is performed by adding 0.5 g of B4C powder as a sintering aid and 4 g of phenol resin as a carbon source to 100 g of α-SiC powder or β-SiC powder having a particle size of about 1.0 μm, In this process, 29 g of PEG (polyethylene glycol) and 1 g of stearic acid are added as molding aids, and these are mixed with methanol as a solvent in a ball mill for 24 hours.

  The granulation step b is granulated by spray-drying the liquid mixture (fluid suspension) obtained in the mixing step a with a spray dryer to obtain a spherical granulated material having a diameter of 30 to 100 μm. It is a process. In the molding step c, the hard granulated material obtained in the granulation step b is filled in a predetermined mold, and then cold press molding (molding pressure: 100 MPa) is performed to obtain a molded body having an annular shape. This is the process.

  The firing step d is a step of firing the molded body obtained in the molding step c in an argon atmosphere at 1850 to 2050 ° C. without applying pressure to obtain a silicon carbide sintered body. The annular material created through this is a sliding material for mechanical seal. And the finishing step e is a step of obtaining a sealing ring by surface polishing (wrapping) one end surface of the silicon carbide sintered body obtained in the firing step d to a mirror surface of Ra = 0.05 to 0.25. It is. The “sealing ring” here is a ring that can be used as both a rotary sealing ring and a stationary sealing ring. In this embodiment, the sealing ring is used as the “static sealing ring 4”. . The mirror surface portion of the stationary sealing ring 4 functions as a sealing surface 4a (sealing end surface) when this is used as a stationary sealing ring (stationary sealing ring 4).

FIG. 4 shows various characteristic tables such as density, porosity, bending strength, and hardness of the seal ring obtained by the above manufacturing method, that is, the seal rings of Examples 1 to 4. The density was measured by a water displacement method, and the porosity was calculated by setting the theoretical density of silicon carbide (SiC) to 3.2 g / cm ³ . As an example, the porosity K1 of Example 1 is K1 = 1− (measured density of sliding material) / (theoretical density) = (1-2.605 / 3.2) × 100 = 18.6 (%). is there. In addition, as shown in the characteristic table of FIG. 4, the sealing rings of Comparative Examples 1 to 4 which are outside the range of the above conditions were also prepared, and the characteristics were confirmed.

  Then, a seal test with industrial water is performed using a mechanical seal (mechanical seal M shown in FIG. 1) incorporating a seal ring according to the present invention, that is, a stationary seal ring 4 and a rotating seal ring 2 made of carbon, for example. The performance of the sealing ring and the sealing performance were confirmed. Further, in order to measure the self-penetration of the sealing ring used as the stationary sealing ring 4, an experimental apparatus A as shown in FIG. 2 is created, and the measured values by the experimental apparatus A are also shown in the characteristic table shown in FIG. It was decided to describe.

The condition of the sliding test using the mechanical seal M shown in FIG. 1 is that the diameter of the seal portion S by the rotating seal ring 2 and the stationary seal ring 4 = 40 mm (unbalanced type), the rotation speed = 3600 rotations / minute, Flushing flow rate = 3 liters / minute, test liquid = industrial water, operation time = 100 hours, liquid temperature = 30 ° C., pressure = 2.5 MPa. In the sliding test results (“sliding characteristics” * in FIG. 4), the meanings of “」 ”,“ ◯ ”,“ Δ ”, and“ X ”are as follows.
A: Wear is not detected in both the rotary seal ring 2 and the stationary seal ring 4. B: The wear amount per unit time is 0.01 μm / hr or less for the rotary seal ring 2 and 0.1 μm for the static seal ring 4. / Hr or less Δ: Wear amount per unit time is 0.01 μm / hr or less for the rotary sealing ring 2 and 0.1 μm / hr or more for the stationary sealing ring 2 ×: per unit time of the rotary sealing ring 2 Wear amount is 0.01μm / hr or more

  Next, the self-penetrating experimental apparatus A will be described. As shown in FIGS. 2 and 3, the experimental apparatus A includes an experimental case main body 21 having a circular recessed portion 23 into which a substantially donut-shaped stationary sealing ring 4 (sealing ring) is loaded, and an internal fit in the circular recessed portion 23. The experimenter 20 includes a lid case 22 fixed to the upper surface of the experiment case main body 21 with a plurality of bolts 24 in a state of covering the upper surface. The experiment case main body 21 is formed with an annular recess 25 that opens to almost the entire outer peripheral surface 2 b of the rotary seal ring 2 loaded in the circular recess 23, and an inlet passage 26 that communicates with the annular recess 25. Yes. A circular large-diameter port 22 </ b> A for measuring the leaked liquid is formed at the center of the lid case 22. Reference numerals 27 and 28 denote O-rings.

  The experiment method of the stationary seal ring 4 by the experimental apparatus A is as follows. In the experimental state (see FIG. 2) in which the stationary seal ring 4 is arranged in the circular recess 23 and covered with the lid case 22 (see FIG. 2), A test solution r having a positive pressure is supplied from the opening inlet passage 26 and fills the annular recess 25 as shown in FIG. The state in which the annular recess 25 is filled with the experimental liquid e is maintained for a predetermined time, and the amount of the test liquid r leaking from the inner peripheral surface 4c of the stationary seal ring 4 is measured. An example of the experimental condition is industrial water applied with a pressure of 2.5 MPa at a temperature of 30 ° C. as the test solution r. The size example of the stationary seal ring 4 is an outer diameter × inner diameter × thickness of φ54 ×. φ40 × 6 (unit: mm).

  The “self-permeability” in the characteristic table of FIG. 4 starts to be measured when leakage can be visually confirmed (see FIG. 3) (measures the liquid that has oozed out from the inner peripheral surface 4c of the stationary seal ring 4). ). In addition, “x” in “self-penetration” means “a leak could not be visually confirmed even when measured for 24 hours (hours)”. FIG. 4A shows various characteristics when the firing temperature is variously changed in the range of 1800 ° C. to over 2200 ° C., and FIG. 4B shows that the sliding characteristics in FIG. About Examples 1-4 whose evaluation is (circle) and (double-circle)), a porosity and the amount of osmotic leakage (self-permeability) are measured.

  Comparative Example 1 had self-penetration, but due to its low sintered density, its strength and hardness were low, and the amount of wear was large (sliding property was x), and the properties as a mechanical seal were insufficient. is there. The comparative examples 2 to 4 have strength and hardness, and there were also those with good sliding characteristics (comparative example 2) (comparative example 2). Occurred and wear was also observed. The thing of the comparative example 3 is a product made from the conventional high density SiC, and is generally used as a SiC sliding material (sealing ring for mechanical seals). Since the test mechanical seal M is under a load condition that far exceeds the selection criteria for the conventional product, the comparative example 3 suffers from wear and surface roughness, and of course is rejected.

From the characteristic table of FIG. 4A by the experimental results, the sealing ring for mechanical seal made of SiC sliding material has a firing temperature of 1850 ° C. to 2050 ° C. and a sintered density of 2.6 g / cm ^{3 to} 3.0 g. It can be seen that this is a SiC sintered body having a strength of 400 MPa or more and a hardness of 1600 hrv or more at / cm ³ . Then, in the SiC sintered body in this case, penetration leakage amount F of the liquid per unit time toward the inner circumferential surface Wc from the outer peripheral surface Wb is in the range of 0.01ml / 24hr ≦ F ≦ 500ml / 1hr . In such a seal ring for mechanical seal, a good mechanical seal function is exhibited even under the above-described overload condition in the mechanical seal M shown in FIG. For reference, the porosity and permeation leakage amount (self-permeability) in the SiC sliding materials of Examples 1 to 4 are shown in FIG. Moreover, the surface condition photograph of each SiC sliding material of Examples 1, 4 and Comparative Examples 1, 2, 4 is shown in FIGS. 5 (a), (b) and FIGS. 6 (a), (b), (c). Shown in

  By the way, when the experiment apparatus A confirms that the permeation leakage amount F is within a specified range (0.01 ml / 24 hr ≦ F ≦ 500 ml / 1 hr), the mechanical seal seal ring itself may not be possible. . That is, if the mechanical seals are different, the sizes (sizes) of the rotating and stationary sealing rings are often different, and therefore may not match the dimensions of the experimental apparatus A. In such a case, an annular body (not shown) is created by machining (cutting, etc.) the sealing ring to a predetermined standard dimension, and leakage by the experimental apparatus A is performed by using the annular body machined to the standard dimension. Quantity measurement is possible. As an example of the standard dimension, the above-mentioned “outer diameter × inner diameter × thickness is φ54 × φ40 × 6 (unit: mm)” may be mentioned, but other dimensions may be used. If the seal ring is smaller than a predetermined standard dimension, a converted value matched to the standard dimension by calculation may be used.

  The static sealing ring (seal ring for mechanical seal) made of a SiC sliding material having self-penetration according to the present invention has discontinuous pores and continuous pores of several μm, and has sufficient strength and hardness. When a certain amount of liquid pressure is applied, the liquid penetrates into the sliding material. Therefore, since the moderately wet state can be maintained by the permeation, the sliding surface is always in a liquid atmosphere, and the dry condition that occurs when starting the mechanical seal, the bearing, and the like is improved, and the start can be performed smoothly. In addition, since the liquid is always sent from the inside to the sliding surface even during operation, a stable liquid film can be continuously formed and the sealing characteristics can be kept good. And there exists an advantage that the quenching effect is acquired because the penetrated liquid accumulates on the atmosphere side.

  As shown in FIG. 1, an intake port 14 for taking in cooling water (an example of a sealing liquid) f supplied to the stationary sealing ring 4 via a liquid passage 3 </ b> W formed in the housing 3. And the dead end-like internal flow path 15 following this is formed. The internal flow path 15 has a longitudinal flow path 15a facing in the radial direction with respect to the axis X and a lateral flow path 15b facing in the direction along the axis X, penetrating through the seal portion S and sealing surface of the rotary seal ring 2 It is comprised in the state obstruct | occluded by 2a. Further, a side circumferential groove 16 for filling with cooling water is formed on the seal surface 4 a of the stationary seal ring 4, which is annular with respect to the axis X and includes the opening on the seal surface side of the internal flow path 15. The side circumferential grooves 16 are preferably annular with respect to the axis X, but are arc-shaped with a predetermined angle with respect to the axis X provided corresponding to each of the plurality of internal flow paths 15 (disposed intermittently in the circumferential direction). It may be a plurality of side circumferential grooves).

  Since the dead-end internal flow path 15 is formed in the stationary seal ring 4 made of a SiC sliding material having self-penetration, the cooling water f penetrates and quickly reaches the seal surface 4a. Compared with the case where the flow path 15 is not formed, the response time from the start of the supply of the cooling water f to the actual seal surface 4a of the stationary seal ring 4 is shortened. That is, responsiveness is improved. The internal flow path 15 penetrates the stationary seal ring 4 and is closed by the seal surface 2a of the rotary seal ring 2, so that the responsiveness is improved and the side circumferential groove 16 is provided to further respond. There is an advantage that the property is improved.

[Example 2]
As shown in FIG. 8, a mechanical seal M having a structure in which an outer peripheral groove 17 for filling a sealing liquid including the intake port is formed on the outer peripheral surface of the stationary seal ring. For example, a plurality of (for example, six) internal flow paths provided at equal angles with respect to the axis X while the outer circumferential groove 17 is annular with respect to the axis X and the liquid path 3W of the housing 3 is single. The cooling water can be smoothly supplied to 15 and the side circumferential groove 16. It is also possible to provide a configuration in which an outer peripheral groove 17 of about 180 degrees with respect to the axis X is provided so as to extend over the two internal flow paths 15 and the side peripheral grooves 16.

  By providing the outer peripheral groove 17, the number of liquid passages 3 W of the housing is reduced to a single number, etc., but the plurality of internal flow paths 15 formed in the stationary sealing ring 4 can be smoothly and inexpensively sealed. There is an advantage that the liquid f can be supplied in a balanced manner.

Example 3
As shown in FIG. 9, the housing 3 has an inward flange portion 3 </ b> A for receiving the outer peripheral side surface 4 d of the stationary seal ring 4, and the intake port 14 provided on the side peripheral surface 4 and the shaft center X are provided. A mechanical seal M with an internal flow path 15 along the direction is also possible. The straight internal flow path 15 is a dead end whose inner end ends just before the seal surface 4a (the end of the internal flow path 15 is located inside the stationary seal ring 4). In this case, a configuration in which an annular side circumferential groove 19 is formed in an open state on the machine-side side circumferential surface 18 of the inward flange portion 3A, and a plurality of internal flow paths 15 are provided at equal angles with respect to the axis X is provided. desirable. The side circumferential groove 19 may be formed on the side circumferential surface 4d of the stationary sealing ring 4.

  By providing the outer peripheral groove 19, the liquid passage 3 </ b> W of the housing 3 is reduced to a single or the like, but the plurality of internal flow paths 15 formed in the stationary seal ring 4 are smoothly and inexpensively sealed. The advantage that the liquid f can be supplied in a well-balanced manner is obtained. Further, according to the structure shown in FIG. 9, there is an advantage that the internal flow path 15 can be easily processed in a straight line and can be formed at a low cost, and the internal flow path 15 does not penetrate the seal surface 4a, and thus penetrates. There is also an advantage that it is possible to increase the area of the sealing surface as compared with the configuration, and to contribute to improving the durability of the seal portion S, that is, the mechanical seal M.

[Another Example]
The sealing fluid is a concept including various kinds of materials such as quenching liquid, flushing liquid, and lubricating liquid in addition to cooling water (cooling liquid).

DESCRIPTION OF SYMBOLS 1 Rotating shaft 2 Rotating sealing ring 2a Sealing surface 3 Housing 4 Static sealing ring 4a Sealing surface 4b Outer peripheral surface 5 Elastic mechanism 14 Intake port 15 Internal flow path 16 Side circumferential groove 17 Outer circumferential groove F Permeation leak amount S Seal part X Shaft center f Sealing liquid

Claims (5)

A rotary seal ring that is supported so as not to rotate relative to the rotary shaft, a stationary seal ring that is supported so as not to rotate relative to the housing, a seal surface of the rotary seal ring, and a seal surface of the stationary seal ring are mutually connected to the rotary shaft. A mechanical seal having an elastic mechanism for pressing in the axial direction to form a seal portion,
The stationary seal ring is made of SiC sliding material,
Water at a temperature of 30 ° C. and a pressure of 2.5 MPa penetrates into the inside from the outer peripheral surface of the annular body formed by processing the stationary seal ring into a predetermined standard size of outer diameter × inner diameter × thickness of φ54 mm × φ40 mm × 6 mm. and the inner circumference and penetration leakage amount per coming out unit time bleeding from surface F with or penetration leakage amount per unit time to come oozed from the inner peripheral surface penetrates the inside from the outer peripheral surface of the stationary seal ring The conversion value F in accordance with the predetermined standard dimension is
0.01ml / 24hr ≦ F ≦ 500ml / 1hr
And is formed of a SiC sliding material having self-penetration property defined in
A mechanical seal in which an intake port for taking in a sealing liquid supplied via the housing and an internal flow path following the intake port are formed in the stationary seal ring.   The mechanical seal according to claim 1, wherein the internal flow path is configured to penetrate the seal portion and be closed by a seal surface of the rotary seal ring.   3. A side circumferential groove for filling a sealing liquid in an annular shape related to the axial center and including a seal surface side opening of the internal flow path is formed on the seal surface of the stationary seal ring. The mechanical seal described.   The mechanical seal according to claim 2 or 3, wherein an outer peripheral groove for filling a sealing liquid including the intake port is formed on an outer peripheral surface of the stationary seal ring.   The mechanical seal according to claim 1, wherein the internal flow path is formed in a dead-end shape whose end is located inside the stationary sealing ring.

Images