JP2002147617A - Seal ring for mechanical seal, and mechanical seal using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanical seal which is largely improved in lubrication performance to a mating seal ring whichever the mating seal ring is of hard material such as silicon carbide or soft material such as carbon, and which is extremely excellent in durability such as abrasion resistance and sealing performance regardless of sealing conditions. SOLUTION: One or both of the two seal rings 1 and 3 rotating to each other to slide is composed of sintered material of silicon carbide in which separate pores of an average pore diameter of 10-40 μm are uniformly disposed at porosity of 3-10%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical seal constructed so that two sealing rings come into sliding contact with each other, and a sealing ring used for the mechanical seal.

[0002]

2. Description of the Related Art As this type of mechanical seal, for example, as shown in FIG. 1, a seal ring (hereinafter referred to as "fixed ring") 1 fixed and held in a seal case 2 and a rotating shaft 4 are movable in the axial direction. The rotating ring 3 is fixed to the stationary ring 1 by being interposed between a rotating ring 3 and a sealing ring (hereinafter referred to as a “rotating ring”) 3 that is held so as not to rotate relative to the rotating ring 4. And sealing springs 6 for pressing and energizing, and sealing end faces 1a and 3a as opposing end faces of both sealing rings 1 and 3.
The end surface contact type, which is configured to seal the in-machine region A, which is the outer peripheral region of the relative rotational sliding contact portion, and the outside air region B, which is the inner peripheral region, of the relative rotational sliding contact portion is well known. One of the sealing rings is made of a hard material such as silicon carbide having excellent thermal, chemical and mechanical properties and abrasion resistance, and the other sealing ring is made of a soft material such as carbon having self-lubricating properties. It is broadly classified into a structure (hereinafter, referred to as “hard / soft seal”) and a structure in which both sealing rings are both formed of a hard material (hereinafter, referred to as “hard / hard seal”).

[0003]

However, in the case of a hard / soft seal, the sealing ring made of a soft material is easily worn and has a problem in durability. For this reason, in general, a carbon material having self-lubricating properties has been used as a soft material to enhance the lubricating properties between the sealing rings to reduce wear of the sealing rings. May cause so-called carbon blisters. On the other hand, in the case of a hard / hard seal, when sealing a slurry fluid containing a solid component,
Although such a problem does not occur, the lubricating property between the sealing end faces is poor, so that noise called so-called squeal may occur between the sealing end faces that slide relative to each other, or a sticking (seizure) phenomenon between the sealing end faces may occur. .

The present invention has been made in view of the above circumstances, and is intended for use in a mechanical seal which can be suitably used as a hard / soft seal or a hard material sealing ring of a hard / hard seal without causing the above-mentioned problems. It is an object of the present invention to provide a sealing ring and to provide a mechanical seal capable of exhibiting a good sealing function without causing the above-mentioned problem by using the sealing ring as at least one sealing ring.

[0005]

Means for Solving the Problems A sealing ring for a mechanical seal according to the present invention which has solved the above problems has the following configuration, and is more preferably configured as follows. In addition, the mechanical seal of the present invention is a hard / hard seal or a hard / soft seal, and one or both of two sealing rings that are in relative rotational sliding contact with each other are as follows, and more preferably. It is configured as follows.

[0006] Independent sintered pores having an average pore diameter of 10 to 40 µm are uniformly dispersed and are formed of a sintered silicon carbide material having a porosity of 3 to 10%.

In the sealing ring having the above configuration,
Unit area (10 ^Fourμm^TwoIndependence per)
The number of pores is 1 or more (usually 1 to 5).

[0008] The sealing ring having the above structure is a spherical hard structure formed by surrounding a silicon carbide powder as a constituent material of a preform to be fired with a gel-like resin layer which is a carbon source and whose curing reaction is not completed. It must be composed of a silicon carbide sintered material using granular material.

Thus, according to the sealing ring having the above structure,
The sealing function (mechanical sealing function) by the relative rotational sliding contact with the mating sealing ring (the sealing ring made of a hard material or the sealing ring made of a soft material) can be satisfactorily exhibited without the problems described at the beginning. That is, a fluid (seal fluid) to be sealed is held by the independent pores present on the sealed end faces (mirror surfaces) of the sealed rings having the above-mentioned configuration between the opposed sealed end faces of the two sealed rings constituting the mechanical seal. In addition, the independent pores function as a kind of oil pot (hereinafter, this function is called "oil pot function"), and a lubricating film is formed between the sealing end faces by the sealing fluid, greatly improving the lubricity between the sealing end faces. I do. Therefore, hard /
For soft seals, mating seal ring (soft material seal ring)
Wear is greatly reduced, and even when the mating seal ring is made of carbon, the generation of frictional heat due to relative rotational sliding contact with the carbon seal ring is prevented as much as possible. There is no possibility that a blister phenomenon (a so-called blister phenomenon) will occur on the sealed end face of the first embodiment. In the case of a hard / hard seal, when the mating seal ring has the configuration described above, it is needless to say that a dense silicon carbide sintered material having no oil pot function or other ceramics, cemented carbide, etc. Even when it is made of a material, it minimizes and prevents heat generation, squealing, and sticking caused by the relative rotational sliding action, reduces the amount of abrasion against slurry containing solid components, and reduces leakage. And a good sealing function without any problem can be exhibited.

In the structure described above, the term "independent pores" means those which exist independently without communicating with other pores. If the pores present on the sealed end face communicate with other pores adjacent to the sealed end face, the leak will occur from the sealed end face and the sealing function cannot be exhibited.

The average pore diameter can be determined by image analysis, and the density (measured density) of the sealing ring for the mechanical seal and the theoretical density of silicon carbide (3.
2 g / cm ² ). That is, porosity = (1− (measured density) / (theoretical density))
X100. Average pore size is 10μ
m or a porosity of less than 3%,
The fluid holding by the independent pores is not sufficiently performed, and the necessary and sufficient oil pot function for improving the lubricity is not exhibited. Conversely, when the average pore diameter exceeds 40 μm or when the porosity exceeds 10%, the strength of the sealed end face may be reduced, and abnormal wear may be caused due to the action of the grindstone by the edge portion of the pore. Further, when the sealing fluid is a slurry liquid or the like containing a solid component, the solid component is likely to enter and be trapped in the independent pores of the sealed end face, and the solid component may cause damage to the sealed end face and abnormal wear. is there.

Further, in order to prevent a decrease in the strength of the sealed end face due to the presence of the independent pores as much as possible and to greatly improve the lubricity by the oil pot function, the average pore diameter and the porosity of the independent pores are set as described above. In addition to the above range, it is necessary that the independent pores are further dispersed uniformly (the average pore diameter and the porosity are necessary conditions, but not sufficient conditions). That is, when the independent pores are not uniformly distributed on the sealed end face,
Even if the average pore diameter and the porosity are in the range, the strength at the sealed end face varies, and the strength of the entire sealed end face decreases.Also, the oil pot function at the sealed end face also varies, resulting in sealing. As a whole, the lubricity by the oil pot function is not so improved as the whole end face.

Whether the independent pores on the sealed end face are uniformly dispersed can be determined by the number of independent pores per unit area (10 ⁴ μm ² ) on the sealed end face. That is, according to the results of experiments, when the sealed end face is divided into unit area regions each having a length of 100 μm and a width of 100 μm, one or more independent pores (1 to 5) exist in all the unit area regions. In this case, the lubricity by the oil pot function was greatly improved without causing a decrease in the strength of the sealed end face due to the presence of the independent pores, but the unit area region where no independent pores existed was 1 area.
When the average pore diameter and the porosity are in the ranges of more than two, it was found that the strength of the entire sealed end face or the lubricity due to the oil pot function was reduced. Therefore, in the present invention, the phrase "independent pores are uniformly dispersed and arranged" in the present invention specifically means that the number of independent pores per unit area (10 ⁴ μm ² ) in the sealed end face is as described in the above. At least one ".

The sealing ring for a mechanical seal of the present invention or the sintered silicon carbide material as a constituent material thereof has a configuration as described above.
The configuration is as follows. By using the material configuration as described above, it is possible to obtain a pore form as described above or to obtain sufficient strength to be used as a sealing ring for a mechanical seal.

The silicon carbide sintered material is generally prepared by adding a sintering aid (boron, aluminum, or a compound thereof) to silicon carbide powder.
Molding (preliminary molding) and baking (sintering) of a granulated material consisting of raw materials to which carbon and carbon sources (carbon powder, resin) are added
In general, a sintered silicon carbide material having pores is formed by a pressing force at the time of pressure molding and firing as compared with a case of producing a normal silicon carbide sintered material (a dense sintered material). (Sintering pressure) is considerably reduced so that pores are formed between the sintered particles, or a resin material for forming voids (for example, polystyrene beads) that can be burned out (pyrolysis, gasification) in the raw material Polymer beads), and the pores formed by the burning are converted into pores. However, when the sintering pressure is reduced as in the former case, the bonding force between the sintered particles is weak, and it is not possible to secure sufficient strength to be able to be used as a sealing ring for a mechanical seal. Further, the bonding state between the sintered particles varies, so that the pores are easily communicated with each other, and it is difficult to obtain independent pores. In addition, when the resin material for forming voids is added to the raw material as in the latter case, a large amount of gas is generated due to the burning out of the resin material, thereby causing cracks in the sintered material, or gas due to segregation of the resin material. The hole diameter tends to vary. further,
The pores are not uniformly dispersed, and the strength of the sintered material may be reduced. Therefore, in any case, it is possible to obtain a porous sintered silicon carbide material, but the porous sintered material having the structure described above and having sufficient strength to be used as a sealing ring for a mechanical seal. It is difficult to get.

However, as a constituent material of the preformed body to be fired, a spherical hard granulated material in which silicon carbide powder is a carbon source and is surrounded by a gel resin layer whose curing reaction is not completed, as described above. If used, press forming and firing processes
By performing it under the same conditions (forming pressure and firing temperature) as when manufacturing a dense silicon carbide sintered material, a silicon carbide sintered material having sufficient strength can be obtained. The hard granulating material does not include the resin material for void formation or the like which disappears completely during firing.

That is, the hard granulated material covered with the gel-like resin layer is harder than the generally used granulated material, so that the hard granulated material is the same as that for producing a dense silicon carbide sintered material. When molding under pressure at molding pressure (for example, 100 MPa),
In the formed body (preformed body), the hard granulated material is hardly crushed unlike the general granulated material, and the spherical hard granulated materials are bonded in a point contact state or in a state close to this point. However, a plurality of voids are formed around the hard granulated material by a portion bonded to the adjacent hard granulated material. These voids are uniform in size and are uniformly dispersed among the hard granulated materials. Therefore, when the preform is fired, each void becomes independent pores in the sintered material, and these independent pores are uniformly dispersed without variation in size. Further, although the gel-like resin layer is a hard material, since the curing reaction is not completed, the adhesiveness between the hard granulated materials in the preform is not impaired, and the hard granulated materials are as described above. Since they are bonded in a point contact state or a state close to this, and the bonding area is small,
The molding pressure acting on the bond is very high. Therefore, the adhesive force between the hard granulated materials in the preformed body is increased, and the bonding force of the silicon carbide particles in the silicon carbide sintered material obtained by firing this is high, and the strength is high. It is equivalent to or close to the material. Further, since the bonding area between the hard granulated materials in the preformed body is small as described above, the forming pressure (for example, 50M) is lower than that in the case of producing a dense silicon carbide sintered material.
Also in the case of preforming in Pa), since the pressure acting on the bonding portion becomes large, the bonding force of the sintered particles can be sufficiently ensured, and the strength of the sintered material does not become insufficient. In addition, since the gel-like resin layer surrounds the silicon carbide powder with a uniform thickness, unlike the case where carbon powder or the like is used as a carbon source, carbon is uniformly dispersed around silicon carbide particles. The sintering is performed in the state where the sintering is performed.
Therefore, the oxygen removing effect of carbon on the surface of the silicon carbide particles is favorably performed, and a high-quality sintered silicon carbide material can be obtained. The preform is formed in a cold state, and the preform is fired in an inert gas atmosphere without pressure.

As a resin used as a carbon source, a thermosetting resin such as a phenol resin is generally used. When a thermosetting resin is used, a mixture of a silicon carbide powder, a sintering aid, and a thermosetting resin solified with a solvent is granulated, and the granulated material is heat-treated at an appropriate temperature. By hardening to a certain extent, that is, by allowing the crosslinking reaction (condensation reaction) of the thermosetting resin to proceed to a certain extent, a hard granulated material covered with a gel-like resin layer in which the crosslinking reaction is not completed is obtained. The heat treatment for gelling the thermosetting resin is performed at a temperature at which the crosslinking reaction of the resin proceeds to a certain extent or more and the crosslinking reaction is not completed.
Done in time. For example, in the case of a phenol resin, about 1
A crosslinking reaction (condensation reaction) is started at 00 ° C., and when the temperature exceeds 150 ° C., the crosslinking reaction is completed and completely cured.
The heat treatment temperature for forming the gel resin layer is 100 ° C.
Keep at 150 ° C. In addition, as long as the carbon source can obtain the same hardness as a thermosetting resin such as a phenolic resin by gelation after granulation (except for those that are completely cured), a thermoplastic resin is used. It is also possible to use.

[0019]

(Example 1) As Example 1, a sealing ring A1 which can be used as a rotating ring 3 of a mechanical seal having the structure shown in FIG. 1 (hereinafter referred to as "the mechanical seal") is manufactured, and the mechanical seal is manufactured. Then, a mechanical seal M1 using a sealing ring A1 as the rotating ring 3 and a carbon sealing ring as the stationary ring 1 was assembled.

The sealing ring A1 is obtained by the following mixing step, granulation step, granulation hardening step, preforming step, firing step, and finishing step.

Mixing step: α- having an average particle diameter of 0.7 μm
To 100 g of SiC powder, 0.5 g of B4C powder as a sintering aid and 4 g of a phenol resin (resole type) as a carbon source were added, and PEG6 was further added as a forming aid.
000 (29 g of polyethylene glycol # 6000 (the numerical value represents the average molecular weight)) and 1 g of stearic acid were added and mixed with methanol as a solvent in a ball mill for 24 hours.

Granulation step: The mixed liquid (fluid suspension) obtained in the mixing step is spray-dried for 60 minutes.
Granulated by spray drying at ~ 80 ° C, diameter 30 ~
A 100 μm spherical granulated material was obtained. This granulated material is S
It is a spherical granule obtained by coating iC powder with a phenol resin layer having a uniform thickness.

Granulation hardening step: Heat treatment (gelation treatment) of the granulated material obtained in the granulation step at 110 ° C. for 2 hours.
Then, the phenol resin layer was cured to the extent that the crosslinking reaction was not completed, and a spherical hard granulated material in which SiC powder was covered with a gel resin layer (phenol resin) having a uniform thickness was obtained.

Preforming step: The hard granulated material obtained in the granulating and hardening step is filled in a predetermined mold, and then cold pressed to form a preformed body having an annular shape corresponding to the rotating ring 3. I got The molding pressure was 50 MPa.

Firing Step: The preformed body obtained in the preforming step was fired in an argon atmosphere at 2150 ° C. without applying pressure to obtain a porous silicon carbide sintered body.

Finishing Step: One end face of the silicon carbide sintered body obtained in the firing step is polished (wrapped) to a mirror surface with Ra = 0.05 to obtain a sealing ring A1. The mirror part of the sealing ring A1 functions as a sealing end face 3a when the sealing ring A1 is used as the rotating ring 3. In addition, three sealing rings A1 were manufactured including those used in Example 4 described later (two).

The density, average pore diameter, porosity, and number of independent pores per unit area of the sealing ring A1 thus obtained were as shown in Table 1. The density was measured by a water displacement method, and the porosity was calculated with the theoretical density of silicon carbide being 3.2 g / cm ³ . That is, porosity = (1− (measured density of sliding material)
/ (Theoretical density)) × 100 = (1- (2.95 / 3.
2)) × 100 = 7.8 (%). The average pore diameter was determined by image analysis and was 40 μm. Further, the number of independent pores per unit area (10 ⁴ μm ² ) is obtained by dividing a mirror surface portion (sealed end face) into a unit area area of 100 μm × 100 μm and dividing the number of independent pores present in each unit area area. This was obtained by confirming that each unit area region had 1 to 5 independent pores. FIG.
Is an enlarged view of the mirror surface (sealed end face) of the sealing ring A1 by a factor of 100. As can be understood from FIG. 2, independent pores (portions shown in black in FIG. 2) are uniform on the sealed end face. Are distributed.

Using the mechanical seal M1 incorporating the rotating ring A1 and the carbon fixed ring 1, a sealing test using industrial water was performed to confirm the performance and sealing performance of the sealing ring. The stationary ring 1 is made of sintered carbon (density: 1.8 g) generally used as a constituent material of a sealing ring.
/ Cm ³ ).

That is, in this seal test, the mechanical seal M1 was sealed with a seal fluid (fluid in the in-machine area A): industrial water, seal pressure: 2.04 MPa, and shaft rotation speed: 360.
0 rpm, PV value: continuously operated under the conditions of 13.08 MPa · m / s for 100 hours.
The leakage amount from outside 3a to the outside atmosphere region B, that is, the leakage amount per 100 hours (cc / 100 hr) was measured. Further, after the operation is completed, the wear amount of the sealing end face 1a in the carbon fixed ring 1, that is, the wear amount per 100 hours (μm /
100 hr). The amount of wear was obtained by measuring the amount of decrease in the length in the axial direction from the back surface of the stationary ring 1 to the front surface (sealed end surface 1a). Table 2 shows the results.
As shown in FIG. That is, the leak amount is only 0.4 cc including the steam leak, and the wear amount is 0.01 μm.
Met.

[0030]

[Table 1]

[0031]

[Table 2]

(Example 2) As Example 2, a sealing ring A2 which can be used as the rotating ring 3 of the mechanical seal was obtained, and the mechanical seal M1 was used except that the sealing ring A2 was used as the rotating ring 3. A mechanical seal M2 having the same configuration was assembled.

The sealing ring A2 was manufactured in the same manner as in Example 1 except that the heat treatment temperature of the granulated material in the granulation hardening process was set to 110 ° C.
This is obtained through the same steps as those described above (mixing step, granulation step, granulation hardening step, preforming step, firing step, finishing step). In addition, three sealing rings A2 were manufactured including those (two) used in Examples 5 and 7 described later.

The density of the sealing ring A2, the average pore diameter, the porosity,
The number of independent pores per unit area was determined in the same manner as in Example 1, and was as shown in Table 1. FIG.
Is an enlarged view of the sealing end face of the sealing ring A2 by 100 times (the portions indicated in black are pores).
The porosity (5.0%) and the average pore diameter (30 μm) are smaller than those of the above. This is because although the heat treatment temperature of the granulated material was lower than that of Example 1, and the hardness of the hard granulated material was slightly lower, the molding pressure was the same as that of Example 1 (50 MPa). This is because the crushing degree of the hard granulated material in the preformed body is increased, that is, the gap between the hard granulated materials is reduced, and as a result, the closed pores are reduced.

Under the same sealing conditions as in Example 1, the mechanical seal M2 was operated for 100 hours, and the amount of leakage (c
c / 100 hr) and the amount of wear (μm / 100 hr). The results were as shown in Table 2. Since the average pore diameter is large enough to exhibit the oil pot function, and the independent pores are uniformly dispersed (the number of independent pores per unit area is 1 to 5 as in A1) ,
The wear amount of the carbon fixed ring 1 was small, and was the same as that of the mechanical seal M1 (0.01 μm). Further, the mechanical seal M1 leaked 0.4 cc, but the mechanical seal M2 did not leak.

(Example 3) As Example 3, a sealing ring A3 usable as the rotating ring 3 of the mechanical seal was obtained, and the mechanical seal M1 was used except that the sealing ring A3 was used as the rotating ring 3. A mechanical seal M3 having the same configuration was assembled.

The sealing ring A3 is the same as the embodiment 1 (mixing step, granulating step, granulating hardening step, preforming step) except that the forming pressure of the preformed body in the preforming step is set to 100 MPa. , Firing step, finishing step). In addition, two sealing rings A3 were manufactured including the one (one) used in Example 6 described later.

The density of the sealing ring A3, the average pore diameter, the porosity,
The number of independent pores per unit area was determined in the same manner as in Example 1, and was as shown in Table 1. The porosity (3.4%) and the average pore diameter (20 μm) are smaller than those of the sealing ring A2 in which the heat treatment temperature of the granulated material is the same. 2, the hardness of the hard granulated material (the hardness of the phenolic resin layer) is the same, but the crushing degree of the hard granulated material in the preformed body is high, that is, the hard granulated material This is because the gap between them becomes smaller, and as a result, the closed pores become smaller. In addition, the number of independent pores per unit area is 1 to
As is clear from FIG. 4 (porous portions are black portions) in which the sealing end face of the sealing ring A3 is enlarged 100 times, independent pores are uniformly distributed on the sealing end face. Have been.

Under the same sealing conditions as in Examples 1 and 2, the mechanical seal M3 was operated for 100 hours, and the amount of leakage (cc / 100 hr) and the amount of wear (μm / 100 h) were measured.
r) was measured. The results are as shown in Table 2,
Leakage and wear of the carbon fixed ring 1 were not observed.

Example 4 As Example 4, the stationary ring 1
A mechanical seal M4 having the same configuration as that of the mechanical seal M1 (except for the rotating ring 3 of the first embodiment) except that a general dense silicon carbide sintered material was used.
(Using the sealing ring A1 obtained in the above). The dense sintered silicon carbide material constituting stationary ring 1 has a density of 3.14.
g / cm ³ , substantially as described in Comparative Example 2 below.
Of the same quality as the sealing ring B2 obtained in the above.

Using this mechanical seal M4, a seal test using industrial water and a seal test using a slurry liquid were performed. In the seal test using industrial water, the operation was performed for 100 hours under the same conditions as in Example 1, and the leakage (cc / 100 hr) after 100 hours had elapsed and the abrasion loss (μm / 100 hr) of the rotating ring A1 were measured. In addition, a seal test using a slurry liquid is performed using a seal fluid (in-machine area A).
Fluid): water slurry containing 4% river sand, sealing pressure: 1.47 MPa, shaft rotation speed: 3600 rpm, PV
Value: Operating continuously for 100 hours under the condition of 13.08 MPa · m / s. During operation, the amount of leakage from between the sealed end faces 1a and 3a to the outside air area B, that is, the amount of leakage per 100 hours (cc / 100hr) Was measured. Further, after the operation was completed, the wear amount of the sealed end face 3a in the rotating ring A1, that is, the wear amount per 100 hours (μm / 100 hr) was measured. The results of these seal tests were as shown in Table 2. That is, in the seal test using industrial water, it was confirmed that no leakage and abrasion occurred and a good sealing function was exhibited. Further, in the sealing test using the slurry liquid, the leakage amount was only 0.3 cc, including the vapor leakage, and the wear amount was 0.01 μm, despite the severe sealing conditions.

Fifth Embodiment As a fifth embodiment, the rotating ring 3
Then, a mechanical seal M5 having the same configuration as the mechanical seal M4 was assembled except that the sealing ring A2 obtained in Example 2 was used. Then, a seal test using industrial water and a seal test using a slurry liquid were performed under the same conditions as in Example 4, and the leakage amount (cc / 100 hr) and the rotation ring A2
Was measured for the amount of wear (μm / 100 hr). The results are as shown in Table 2, and it was confirmed that a good sealing function was exhibited regardless of the sealing fluid.

(Embodiment 6) As Embodiment 6, the rotating ring 3
A mechanical seal M6 having the same configuration as that of the mechanical seal M4 was used except that the sealing ring A3 obtained in Example 3 was used. Then, a seal test using industrial water and a seal test using a slurry liquid were performed under the same conditions as in Example 4, and the leakage amount (cc / 100 hr) and the rotating ring A3
Was measured for the amount of wear (μm / 100 hr). The results are as shown in Table 2, and it was confirmed that a good sealing function was exhibited regardless of the sealing fluid.

(Example 7) In Example 7, a sealing ring A4 usable as the stationary ring 1 of the mechanical seal was obtained, and the sealing ring A4 was used as the stationary ring 1 and the rotating ring 3 was used in Example 2. A mechanical seal M7 having the same configuration as that of the mechanical seal M4 was assembled except that the obtained sealing ring A2 was used.

The sealing ring A4 is the same as that of the embodiment described above except that a molding die in the preforming step can be used to obtain a preformed body having a shape corresponding to the stationary ring 1 which can be used for the mechanical seal. 2 obtained by the same process (mixing process, granulation process, granulation hardening process, preforming process, firing process, and finishing process) as shown in Table 1. It is made of binder.

Using the mechanical seal M7, a seal test using industrial water and a seal test using a slurry liquid were performed under the same conditions as in Example 4, and the leakage amount (cc / cc) was measured.
100 hr) and the amount of wear (μm / 100 hr). The results are as shown in Table 2. No leakage and no wear of the sealing rings A2 and A4 were observed regardless of the sealing fluid. From this fact, by using the sealing ring of the present invention for the stationary ring 1 and the rotating ring 3, compared with the case where the sealing ring of the present invention is used for one of the sealing rings 1 and 3 as in Examples 1 to 6, As a result, it was confirmed that the sealing function was further improved, and the same sealing function was exhibited under any sealing conditions.

(Comparative Example 1) As Comparative Example 1, a sealing ring B1 that can be used as the rotating ring 3 of the mechanical seal was manufactured, and was the same as the mechanical seal M1 except that the sealing ring B1 was used as the rotating ring 3. The mechanical seal N1 having the above configuration was assembled.

The sealing ring B1 was obtained by the same process as in Example 3 except that the heat treatment temperature in the granulation hardening process was 160 ° C. In addition, two sealing rings B1 were manufactured including the one (one) used in Comparative Example 4 described later.

By setting the heat treatment temperature of the granulated material to 160 ° C., the crosslinking reaction of the phenol resin constituting the outer surface layer of the granulated material has been completed, and the phenol resin layer is in a completely cured state. ing. Accordingly, despite the fact that the preformed body is formed at a high forming pressure (100 MPa) as in Example 3, the adhesion between the granulated materials is not sufficiently performed. As shown in FIG. 5, which shows the sealing end face of the sealing ring B1 at a magnification of 100 times, the pores (black portions in FIG. 5) communicate with each other in the form of a long hole. No pores. Therefore, the number of independent pores per unit area (10 ⁴ μm ² ) for specifying the uniform arrangement of independent pores cannot be obtained. The density, average pore diameter, and porosity of the sealing ring B1 were obtained in the same manner as in Example 1, and are as shown in Table 1.

When a seal test was performed using industrial water under the same conditions as in Example 1 using the mechanical seal N1, the pores at the sealing end face of the sealing ring B1 were continuous. , 3a caused seepage leakage. Therefore, the continuation of the seal test was meaningless and was stopped. Also, the measurement of the abrasion amount of the sealing end face could not be measured because of the occurrence of permeation leakage.

(Comparative Example 2) As Comparative Example 2, a sealing ring B2 that can be used as the rotating ring 3 of the mechanical seal was manufactured, and was the same as the mechanical seal M1 except that the sealing ring B2 was used as the rotating ring 3. The mechanical seal N2 having the above configuration was assembled.

The sealing ring B2 was obtained by the same process as in Comparative Example 1 except that the granulation hardening process was not performed.
That is, without heat treatment of the granulated material, 100MPa
, And the obtained preformed body is fired. The manufacturing method of the sealing ring B2 is the same as that of a general dense silicon carbide sintered material. Therefore, the sealing end face of the sealing ring B2 is shown in FIG.
As shown in the figure, there is no independent pore that is dense and can function as an oil pot.
Uses sealing rings 1 and 3 made of dense silicon carbide. The density, average pore diameter, and porosity of the sealing ring B2 shown in Table 1 were determined in the same manner as in Example 1. In addition, two sealing rings B2 were manufactured including the one (one) used in Comparative Example 5 described later.

Using the mechanical seal N2, a seal test using industrial water was performed under the same conditions as in Example 1. The results are as shown in Table 2, and the function as a hard / soft seal in combination with the carbon sealing ring is as follows. It was inferior to the mechanical seals M1, M2, M3 using A2, A3.
Further, the lubricating properties are inferior to those of the mechanical seals M4, M5, M6, and M7, which are hard / hard seals having no self-lubricating property, and the amount of leakage and wear are increased.

(Comparative Example 3) As Comparative Example 3, a sealing ring B3 usable as the rotating ring 3 of the mechanical seal was manufactured, and was the same as the mechanical seal M1 except that the sealing ring B3 was used as the rotating ring 3. The mechanical seal N3 having the above configuration was assembled.

The sealing ring B3 is used as a raw material of the mixed solution obtained in the mixing step, and is used as a resin for forming a void in an amount of 50-60 μm.
The point that 10 g of m-diameter polystyrene beads were added was used. The granulated material (30 to 100 μm diameter) obtained in the granulation step was directly processed to 100 M without going through the granulation hardening step.
It was obtained by the same process as in Example 1 except that a preform was obtained by press molding with Pa. The sealing ring B3 is used in Comparative Example 6 described later (one piece).
And two were produced.

In the sealing ring B3, independent pores are formed by burning out the polystyrene beads in the firing step. However, as described at the beginning, due to gas generation due to burning (decomposition, dissipation) of the beads, the sealing ring B3
In the closed pores, there is a large variation in size and distribution. That is, in the sealing ring B3, as shown in FIG. 7 and Table 1 in which the sealing end face is magnified 100 times, the average pore diameter is large (60 μm) and independent pores per unit area (10 ⁴ μm ² ) at the sealing end face. The number cannot be specified (there is a unit area region in which one or more independent pores exist and a unit area region in which no independent pores exist, and the independent pores are unevenly distributed). I haven't. The density, average pore diameter, porosity, and number of independent pores per unit area of the sealing ring B3 in Table 1 were determined in the same manner as in Example 1.

Then, a seal test using industrial water was performed under the same conditions as in Example 1 using the mechanical seal N3. The results are as shown in Table 2. The leakage amount and the wear amount of the carbon fixed ring 1 were larger than those of the mechanical seal N2 using the rotating ring B2 made of dense silicon carbide sintered material, and the sealing function was further improved. Dropped. This is because the independent pores in the sealing end face are not large and are not uniformly distributed, so that the oil pot function is not exerted, and instead, a grinding wheel action is caused by the peripheral edge of the independent pores.

Comparative Example 4 As Comparative Example 4, the rotating ring 3
A mechanical seal N4 having the same configuration as that of the mechanical seal M4, except that the sealing ring B1 obtained in Comparative Example 1 was used. Then, a seal test using industrial water and a seal test using a slurry liquid were performed under the same conditions as in Example 4. As a result, in any case, the mechanical seal N1 which is a hard / soft seal using the sealing ring B1 is used.
In the same manner as in the above, permeation leakage occurred, and the mechanical seal function could not be exhibited.

Comparative Example 5 As Comparative Example 5, the rotating ring 3
A mechanical seal N5 having the same configuration as that of the mechanical seal M4, except that the sealing ring B2 obtained in Comparative Example 2 was used. Then, a seal test using industrial water and a seal test using a slurry liquid were performed under the same conditions as in Example 4, and the leakage amount (cc / 100 hr) and the rotating ring B2
Was measured for the amount of wear (μm / 100 hr). The results are as shown in Table 2. As compared with the mechanical seal N2 using the self-lubricating carbon fixed ring 1 as the stationary ring 1, the lubricating property was inferior, and the leakage and wear increased. That is, as compared with the mechanical seals M1 to M7 having better lubricity than the mechanical seal N2, the sealing function including the leakage amount and the wear amount is significantly reduced.

Comparative Example 5 As Comparative Example 6, the rotating ring 3
A mechanical seal N6 having the same configuration as that of the mechanical seal M4, except that the sealing ring B3 obtained in Comparative Example 3 was used. Then, a seal test using industrial water and a seal test using a slurry liquid were performed under the same conditions as in Example 4, and the leakage amount (cc / 100 hr) and the rotating ring B3
Was measured for the amount of wear (μm / 100 hr). The results are as shown in Table 2, and despite the presence of independent pores in the sealed end face, they did not satisfy the opening condition, so that improvement in lubricity by the oil pot function could not be expected. However, only the mechanical seal N5 which uses a dense silicon carbide sintered material for both sealing rings exhibits the same sealing function.

[0061]

As will be easily understood from the above description, according to the present invention, the lubricity between the sealing ring and the mating seal ring is greatly improved in both the hard / hard seal and the hard / soft seal. And regardless of the sealing conditions,
It is possible to provide a mechanical seal that is extremely excellent in durability such as abrasion resistance and sealing properties.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing an example of a mechanical seal.

FIG. 2 is a pore distribution diagram showing a micrograph of the sealing end face of the sealing ring A1 magnified 100 times.

FIG. 3 is a pore distribution diagram showing a micrograph of a sealed end face of a sealing ring A2 magnified 100 times.

FIG. 4 is a pore distribution diagram showing a micrograph of the sealing end face of the sealing ring A3 magnified 100 times.

FIG. 5 is a pore distribution diagram showing a micrograph of the sealing end face of the sealing ring B1 magnified 100 times.

FIG. 6 is a pore distribution diagram showing a micrograph of the sealing end face of the sealing ring B2 magnified 100 times.

FIG. 7 is a pore distribution diagram showing a micrograph of the sealing end face of the sealing ring B3 magnified 100 times.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fixed ring (sealing ring), 1a ... Sealed end surface of fixed ring, 3 ...
Rotating ring (sealing ring), 3a...

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyotaka Yida 2-66-3, Nagatano-cho, Fukuchiyama-shi, Kyoto F-term in Fukuchiyama Works of Nippon Pillar Industry Co., Ltd. F term (reference) 3J041 AA01 BA04 BC02 DA01 4G019 GA04

Claims (2)

[Claims] 1. A sealing ring for a mechanical seal, wherein independent sealing pores having an average pore diameter of 10 to 40 .mu.m are uniformly dispersed and formed of a silicon carbide sintered material having a porosity of 3 to 10%. . 2. A sintered silicon carbide material in which one or both of two sealing rings which are in relative rotational sliding contact have independent pores having an average pore diameter of 10 to 40 μm uniformly arranged and a porosity of 3 to 10%. A mechanical seal characterized by comprising: