JP3308937B2 - Non-contact type shaft sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a turbine, for example,
The present invention relates to a non-contact type shaft sealing device used for shaft sealing between a rotating shaft and a casing in a shaft sealed device such as a blower, a compressor, a stirrer, and a rotary valve.

[0002]

2. Description of the Related Art An example of a conventional structure of a non-contact type shaft sealing device as described above will be described with reference to FIG. In the figure, reference numeral 51 denotes a rotating shaft of the shaft-sealed device.
The outer periphery of the rotary ring 52 is airtightly fitted to the outer ring 1. On the other hand, a first seal case 54 and a second seal case 55 respectively surrounding the rotary shaft 51 are sequentially attached to the housing 53 of the shaft-sealed device, and a seal ring is provided between the first seal case 54 and the rotary shaft 51. Reference numeral 56 is disposed so as to be movable in the axial direction. Opposing surfaces of the seal ring 56 and the rotary ring 52 are formed as seal surfaces 56s and 52s, respectively.

[0003] A spring 57 for pressing the seal ring 56 toward the rotating ring 52 is disposed outside the seal ring 56 (left side in the figure). An air supply hole 56a is formed in the seal ring 56 from the outer peripheral surface to the seal surface 56s.
Through a, a barrier gas such as nitrogen gas is supplied to the seal surface 56s.

A gas supply hole 54a for introducing the barrier gas from outside is formed in the first seal case 54, and the gas supply hole 54a is provided between the first seal case 54 and the seal ring 56. O-rings 58 and 59 are interposed on both sides with respect to the direction, and a manifold space C for interconnecting the gas supply hole 54a and the air supply hole 56a is formed between them. O-ring 58
Out of 59, the inside space A is sealed on the outer peripheral side of the seal ring 56 by the O-ring 58 on the right side in the figure.

In such a configuration, the seal ring 5
6 and the respective seal surfaces 56s and 52s of the rotating ring 52 (hereinafter, referred to as
When the barrier gas is supplied to the seal surface gap, the barrier gas flows out from the seal surface gap toward the inner peripheral side and the outer peripheral side. 56 acts as a force for pushing the opening 56 in the opening direction (left direction in the figure). This holds the seal ring 56 at a position where it opposes the spring force of the spring 57, so that the seal ring 56 is not in contact with the rotating ring 52, and the seal surface 56s
The communication of the inside space A to the outside of the machine is cut off by the barrier gas filling for 52 s, and the shaft sealing is achieved.

Incidentally, in a shaft-sealed device provided with the above-mentioned non-contact type shaft-sealing device, usually, for example, a predetermined atmospheric gas is introduced into the machine, and an operation is performed while maintaining a predetermined gas pressure. At this time, the in-machine gas pressure acts on the seal ring 56 as an axial pushing force. Therefore, in order to prevent the stability of the non-contact shaft sealing state from being impaired by such fluctuations in the gas pressure in the machine, the conventional seal ring 56 includes
A communication hole 60 extending from the shoulder on the outer peripheral side at the front end (right end in the drawing) where the seal ring 56 is exposed to the in-machine space A to the rear end face is formed in a pore shape penetrating the seal ring 56 in the axial direction. .

At the rear of the seal ring 56, that is, in the area where the spring 57 is disposed, an O-ring 59 on the left side in the figure of the manifold space C and an O-ring 61 provided on the inner periphery on the rear end side of the seal ring 56. A closed space E is formed by this. This rear space E
The in-flight gas flows through the communication hole 60 to
The pressure in the rear space F is the same as that of the inside of the machine, so that the sealing ring 56 is acted upon by a forward pressing force due to the gas pressure in the machine.

In this configuration, as shown in FIG.
On the sealing surface 56 s of the seal ring 56, an opening force Fo in which the opening force for pushing the gas pressure in the apparatus backward and the opening force due to the supply of the barrier gas are superimposed, while the sealing ring 56.
A spring force Fc1 of the spring 57 and a closing force Fc2 for pushing the in-flight gas flowing into the rear space E forward act on the rear end surface of the rear end face, and as shown in FIG. The seal ring 56 is held at a position where the resultant force with the closing force Fc2 by the in-machine gas balances with the opening force Fo. The closing force Fc2 due to the in-flight gas pressure in the rear space E is formed so as to be substantially balanced with the opening force due to the in-flight gas pressure of the opening force Fo. The contact shaft sealing state is stably maintained.

[0009]

However, in the above-mentioned conventional non-contact type shaft sealing device, the seal ring 5 is not provided.
6, a communication hole 60 is formed through the seal ring 56 in the axial direction in order to apply the in-machine gas pressure to the rear end side. Therefore, it is necessary to form a closed rear space E behind the seal ring 56, and therefore, there is a problem that the overall structure becomes complicated.

Further, for example, when a non-contact type shaft sealing device as described above is provided in a stirrer or the like for stirring a chemical raw material or a food raw material, after the stirring operation is completed and the raw material is taken out, the inside of the device is for example steamed. It is necessary to perform sterile cleaning, but at this time, it is not easy to clean the inside of the closed rear space E into which the in-machine gas has flowed through the communication hole 60. It remains and further causes decay of the raw material powder contained therein.
For this reason, there is also a problem that it cannot be used for equipment that requires cleaning as described above.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned conventional problems, and has as its object to stably maintain a non-contact shaft sealing state with a simple configuration, and to communicate with the inside of a machine. An object of the present invention is to provide a non-contact type shaft sealing device in which an area to be cleaned can be easily cleaned.

[0012]

Accordingly, a non-contact type shaft sealing device according to the present invention comprises a rotating ring provided on a rotating shaft of a shaft-sealed device, a seal case fixed to a housing of the shaft-sealed device, A seal ring disposed between the seal case and the rotating shaft so as to be axially movable from the outside of the rotating ring to the rotating ring in an axial direction, and a seal ring interposed between the seal ring and the seal case, and A sealing member for sealing the space,
Biasing means for pressing the seal ring toward the rotating ring, a barrier gas is supplied between the sealing surfaces of the sealing ring and the rotating ring facing each other through an air supply hole formed in the sealing ring, and between these sealing surfaces. What is claimed is: 1. A non-contact type shaft sealing device formed so as to seal a shaft, wherein said seal ring has a seal ring holding portion internally fitted in said seal case to hold said seal ring in said seal case. A sealing end face forming portion that protrudes radially outward from the seal ring holding portion in the inboard end region than the portion,
While the seal member is interposed on the outer peripheral surface of the seal ring holding portion, the seal surface is arranged on the inboard end surface of the sealed end surface forming portion such that the outer peripheral edge thereof is located radially outward from the seal ring holding portion. It is characterized by forming.

According to this configuration, the internal pressure acts as an opening force for pressing the seal ring against the outside of the machine against the inside end face of the sealed end face forming portion, and at the same time, acts on the outside end face of the sealed end face forming portion. And acts as a closing force to press the seal ring inward. In the above, the seal surface is formed such that the outer peripheral edge of the seal surface is located radially outward of the seal ring holding portion, whereby the opening force generated by the internal pressure acting on the seal surface is prevented. This closing force can be generated in a region between the outer peripheral surface of the seal ring holding portion and the outer peripheral edge of the seal surface in each radial position on the outside end surface of the sealed end surface forming portion.

Therefore, by setting the positional relationship in the radial direction between the outer peripheral surface of the seal ring holding portion and the outer peripheral edge of the seal surface so that these are substantially balanced with each other, the seal ring is not affected by fluctuations in the internal pressure of the machine. In addition, the opening force due to the gas pressure of the barrier gas supplied between the sealing surfaces and the closing force by the urging means are held at a position where they substantially oppose each other, so that the non-contact shaft sealing state is stably maintained. You.

In addition, in the above configuration, when the internal pressure is applied in the closing direction, there is no need to form a communication hole penetrating the seal ring in the axial direction or a closed space outside the seal ring. The configuration can be simplified. Further, for example, since the in-machine gas invades only the region on the front end side of the seal ring from the inside of the machine beyond the sealing end surface forming portion to the sealing position by the seal member, even when cleaning the region exposed to the in-machine gas or the like. This can be done easily.

In the non-contact type shaft sealing device of the present invention, a cleaning fluid supply hole for supplying a cleaning fluid to the space between the outside end face of the sealing end face forming portion and the seal case in the seal case. Is formed.

According to this configuration, for example, when the space between the outer end face of the sealed end face forming portion and the seal case is made small, it is difficult to clean this space area from the inside of the machine. In the above, since the cleaning fluid can be supplied to the space region through the cleaning fluid supply hole formed in the seal case, the cleaning of this region is also facilitated, and the region does not need to have an excessive space shape. Therefore, the whole can be configured more compactly.

[0018]

Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 2 shows a non-contact type shaft sealing device 1 according to the present embodiment. In FIG. 1, reference numeral 2 denotes a rotating shaft of a shaft-sealed device such as a stirrer used for manufacturing a chemical or the like. Reference numeral 3 denotes a housing that surrounds an internal space of the shaft-sealed device (hereinafter, referred to as in-machine A).

An end face 3 of a housing 3 is
A sleeve 4 extending toward the atmosphere side B from substantially the same axial position as a is externally fitted and fixed. The sleeve 4 is formed with an end flange 4a with a slightly larger end on the in-machine A side. A ring-shaped rotating ring 5 which is sequentially adjacent to the end flange portion 4a from the atmosphere side B and spreads in the radial direction;
A thin cylindrical stopper ring 6 is fitted over the sleeve 4.

The stopper ring 6 is provided with a threaded portion 6a which is screwed to the outer periphery of the sleeve 4 in the end region on the atmosphere side B. By tightening the stopper ring 6 toward the inside A of the machine,
An end region of the rotating ring 5 on the axial center side is sandwiched between the end surface of the stopper ring 6 and the end flange 4 a, and the rotating ring 5 is fixed to the sleeve 4. A slinger 7 is further provided on the atmosphere side B than the stopper ring 6, and the slinger 7 is fixed to the sleeve 4 by a set screw 8 in contact with an end surface of the stopper ring 6.

On the other hand, a mounting flange 11 for covering the outer peripheral side of the opening 3b of the housing 3 is fixed to the end face 3a of the housing 3. A center through hole 11 a having a diameter larger than the outer diameter of the rotating ring 5 is formed in the mounting flange 11, and a first seal case 12 and a second seal case 13 are formed on the inner peripheral end surface of the mounting flange 11. The first bearing housing 14 and the second bearing housing 15 are the fastening bolts 1
6 is fixed by screwing it through the mounting flange 11 through these 12 to 15.

A seal ring 21 to be described later is arranged between the inner surface of the first seal case 12 and the stopper ring 6. A bearing 17 is provided between the inner surface of the second bearing housing 15 and the outer surface of the sleeve 4, and the seal cases 12 and 13 and the bearing housing 1 are provided.
The bearings 4 and 15 are held by the bearing 17 in an assembled state concentric with the rotating shaft 2.

Oil seals 18 are provided between inner ends of the first bearing housing 14 and the second bearing housing 15 on both axial sides of the bearing 17 and outer surfaces of the sleeve 4, respectively. I have. On the other hand, in order to maintain the airtightness on the inside A side, the O-rings 19.
Between the inner peripheral surface of the end of the sleeve 4 on the in-machine A side and the outer peripheral surface of the rotary shaft 2, between the end flange 4 a of the sleeve 4 and the rotary ring 5, and between the housing 3 and the mounting flange 11. ,
They are interposed between the mounting flange 11 and the first seal case 12, respectively.

As shown in FIG. 1A, the first seal case 12 has a gas supply hole 12a penetrating in the radial direction. The gas supply hole 12 is provided between the inner peripheral surface of the first seal case 12 and the outer peripheral surface of the seal ring 21.
O-rings 22 and 23 are arranged on both sides of the gas supply hole 12a in the axial direction, and the gas supply hole 12a is provided between the inner surface of the first seal case 21 and the outer surface of the seal ring 21 between the O-rings 22 and 23. A manifold space C into which the gas supplied through the gas flows is formed.

The second seal case 13 is integrally formed with a spring retainer portion 13a facing the rear end face (left end face in the figure) of the seal ring 21 from the rear inside in the radial direction. On the other hand, on the rear end face of the seal ring 21, a plurality of spring insertion holes 21a which are recessed in the axial direction are formed in the circumferential direction. A spring holding pin 24 extending into each of the spring insertion holes 21a is erected on the spring retainer 13a, and a spring (biasing means) 25 composed of a compression coil spring is disposed around each of the holding pins 24. I have. These springs 25 have their rear ends in contact with the end faces of the spring retainer portion 13a, and
1a, and the spring force of these springs 25 is configured to act as an urging force for pressing the seal ring 21 in the machine A side in the axial direction.

The seal ring 21 is connected to the seal ring 21 so that the manifold space C communicates with the front end face (the right end face in the figure) of the seal ring 21.
A plurality of air supply holes 21b penetrating the inside in a substantially rectangular shape are formed at equal intervals in the circumferential direction. At the front end side of these air supply holes 21b, pocket grooves 21c having a substantially triangular cross section whose radial width has been expanded to a predetermined size are formed, and these pocket grooves 21c have a shape opened to the front end face of the seal ring 21. I have. On the other hand, an orifice 21d is interposed as a throttle mechanism in each of the air supply holes 21b on the manifold space C side.

The seal ring 21 is provided at its front end side with a sealed end face forming portion 21e which spreads radially outward. That is, the rear end side of the seal ring 21 from the substantially intermediate position in the axial direction is formed as a seal ring holding portion 21f having a small diameter.
f, the first seal case 1 on both sides of the manifold space C.
The seal ring 21 is held in the seal cases 12 and 13 by being fitted inside the second and second seal cases 13. Then, the front end side is connected to the seal ring holding portion 2.
The sealing end face forming portion 21e is formed to have a shape that expands in a substantially trapezoidal cross section from the outer peripheral surface of 1f. The pocket groove 21c is open at a radial position substantially intermediate between the inner peripheral surface and the outer peripheral surface of the inner end surface on the in-machine A side of the sealed end surface forming portion 21e. The end face of the sealed end face forming portion 21e is provided with a stepped surface protruding toward the in-machine A side over a predetermined width with the pocket groove 21c at the center in the radial direction, and this stepped surface is a seal surface 21s. At the end face of the rotary ring 5 facing the seal surface 21s, a step surface slightly recessed into the machine A side is formed, and this step surface is formed as a seal surface 5s of the rotary ring 5.

The pocket groove 21c is formed so as to open at a position substantially in the same radial direction as the outer peripheral surface of the seal ring holding portion 21f, or at a position slightly inside the outer peripheral surface of the seal ring holding portion 21f. Have been. Therefore, the above-described air supply hole 21b is formed in the manifold space C.
Is inclined obliquely outward from the inside of the pocket groove 21c and communicates with the pocket groove 21c.

Further, corresponding to the above outer peripheral shape of the front end side of the seal ring 21, the front end side of the manifold space C is recessed radially outward from the first seal case 12 surrounding the first seal case 12. A notch recess 12b is provided. A front end side communicates with the interior A between the notch recess 12b and the sealed end face forming part 21e, and the sealed end face forming part 2e.
An in-machine communication space D reaching behind 1e is formed. The in-machine communication space D is sealed from the manifold space C on the right side in the figure of the manifold space C by an O-ring 22 interposed on the outer peripheral surface of the seal ring holding portion 21f. Therefore, in the present embodiment, the O-ring 22 is configured to also function as a seal member for sealing the space inside the machine between the first seal case 12 and the seal ring 21.

As shown by a broken line in FIG. 2, the first seal case 12 has a shape in which a steam supply hole (cleaning fluid supply hole) 12b opening in the in-machine communication space D further penetrates in the radial direction. Is formed. The gas supply hole 1
A barrier gas supply pipe 28 in which a filter 26 and a first opening / closing valve 27 are sequentially provided is connected to 2a. Through this supply pipe 28, a barrier gas BG such as dry air or nitrogen gas is supplied to the manifold space C. You.

On the other hand, a steam supply pipe 30 provided with a second on-off valve 29 is connected to the steam supply hole 12b.
After the above-described stirring operation in the production of chemicals and the like is completed, when the inside of the apparatus is sterilized and washed, the steam supply pipe 3 is used.
The steam S is supplied to the in-machine communication space D through 0.
The steam supply pipe 30 and the barrier gas supply pipe 28 are connected to the bypass pipe 3 in which the third on-off valve 31 is provided.
2 are interconnected.

When, for example, a chemical raw material or the like is supplied to a shaft-sealed device provided with the non-contact type shaft-sealing device having the above-described structure and operation is started, first, an operation of opening the first on-off valve 27 is performed. . As a result, the barrier gas BG passes through the barrier gas supply pipe 28 to the gas supply holes 12a of the first seal case 12.
Supplied to The barrier gas BG flows from the manifold space C into each of the air supply holes 21b, and is appropriately narrowed by the orifice 21d.
1c. Thereby, each pocket groove 21c
The gas pressure generated inside acts as a force for pressing the seal ring 21 backward. As a result, spring 2
5, the sealing surface 21s is pressed forward by the rotating ring 5
The seal ring 21 held at a position where it abuts against the seal surface 5s moves rearward against the spring force of the spring 25, and the seal surface 21s
Separated from s.

When a gap is formed between the two sealing surfaces 21s and 5s, the barrier gas BG supplied to the pocket groove 21c passes through the gap between the two sealing surfaces 9s and 2s, that is, the gap between the sealing surfaces, and the inner and outer peripheral sides. There will be a flow out to the side. In such a flow state,
The gas pressure generated in the seal surface gap acts as a force for pressing the seal ring 21 in the opening direction (left direction in the figure),
The seal ring 21 is held at a position where this opposes the spring force of the spring 25. Therefore, the seal ring 21 is brought into a non-contact state with the rotary seal ring 2, and the shaft sealing is achieved by the barrier gas BG that fills between the seal surfaces 2 s and 9 s.

When stirring the above-mentioned chemical raw materials or the like, a predetermined atmospheric gas is introduced into the shaft-sealed device, and the device is operated under a predetermined pressure state and a predetermined temperature state. At this time, if the gas pressure in the cabin A is higher than the atmospheric pressure,
This gas pressure in the machine acts as a force for pushing the seal ring 21 in the axial direction.

FIG. 1B shows the seal ring 2 at this time.
1 shows an action state of an axial pushing force with respect to No. 1. First, a spring force Fs1 by the spring 25 acts on the rear end side of the seal ring 21 as a closing force for moving the seal ring 21 rightward in the drawing. On the other hand, seal ring 2
1, the gas pressure in the machine acts on a region on the outer peripheral side of the seal surface 21 s, as is apparent from FIG.
Further, the in-machine gas generates a pressure distribution that gradually decreases from the in-machine gas pressure level at the outer peripheral edge toward the inner peripheral edge even in the region of the seal surface gap, and the barrier gas is supplied through the air supply hole 21b. The pressure distribution by supplying BG is superimposed. As a result, an opening force based on the pressure distribution indicated by Fo in FIG. 4B acts on the sealing surface 21s, and an opening force Fop based on the in-machine gas pressure acts on the outer peripheral side of the sealing surface 21s. .

Further, as shown in FIG. 3A, as a result of the in-machine gas entering the above-described in-machine communication space D, the in-machine gas pressure also increases at the rear end inclined end face of the sealed end face forming portion 21e. It acts as a force to push the seal ring 21 rightward in the figure. These are shown as Fsp and Fs2 in FIG. These Fsp
Fs2 is divided into an outer side and an inner side across a radial position equivalent to the position of the outer peripheral edge of the seal surface 21s, and the closing force based on the in-machine gas pressure acting on the outer region Sp is represented by Fsp,
The closing force based on the in-machine gas pressure acting on the inner region Si is represented by Fs2
And

Here, Fsp is the sealing end face forming portion 21.
This is equivalent to the opening force Fop acting on the right end side with respect to e. Therefore, in the operating state in which the in-machine gas pressure acts on the seal ring 21 as described above, as shown in FIG.
At the axial position where the total closing force of s1 and the closing force Fs2 acting on the above-described inner region Si of the rear end face of the sealing end face forming portion 21e is balanced with the opening force Fo acting on the sealing surface 21s. Is held, and the rotating ring 5
Is a non-contact shaft sealing state.

The sealing end face forming part 21e is provided with a sealing face 21s
Among the opening forces Fo acting on the inner region S, a closing force substantially balanced with the opening force based on the pressure distribution of the in-device gas is obtained by the in-device gas acting on the inner region Si.
The shape is set by obtaining the pressure receiving area in the axial direction at i. Therefore, even if the in-machine gas pressure fluctuates in the above operating state, the change in the axial pushing force due to the in-machine gas pressure occurs simultaneously in the opening direction and the closing direction. Therefore, the seal ring 21 is stably maintained in the non-contact shaft sealing state almost without being affected by the fluctuation of the gas pressure in the machine as described above.

When the gap between the sealing surfaces is widened due to, for example, mechanical vibration or the like in the non-contact shaft sealing state as described above, the pressure distribution in the gap between the sealing surfaces due to the barrier gas BG is accordingly reduced. As a result, the seal ring 21 moves in a direction to narrow the gap between the seal surfaces. vice versa,
When the gap between the sealing surfaces is reduced, the gap moves in a direction to increase the gap between the sealing surfaces. In other words, an automatic gap adjusting function for keeping the gap between the sealing surfaces constant against disturbance is exhibited.

In such a non-contact shaft sealing state, a motor (not shown) is operated, and the rotating shaft 2 is rotationally driven, so that
Stirring of the chemical raw material and the like in the shaft-sealed device is performed, and during this time, the above-described non-contact shaft sealing state between the rotating ring 5 and the seal ring 21 that rotates integrally with the rotating shaft 2 is maintained.

When the stirring operation is completed in this way, the chemical raw materials and the like are taken out from the inside of the machine A, and thereafter, steam is supplied to the inside of the machine A to perform sterilization washing. At this time, in the non-contact type shaft sealing device having the above-described configuration, by closing the first opening / closing valve 27 and opening the second opening / closing valve 29 shown in FIG. The air is supplied to the internal communication space D through the 12 steam supply holes 12b. Thus, the in-machine communication space D into which the in-machine gas has entered can be easily sterilized and cleaned.

As described above, in the non-contact type shaft sealing device of the present embodiment, the O-ring 22 for sealing the internal space between the seal ring 21 and the first seal case 12.
In the end region of the seal ring 21 on the inner side of the machine, the sealed end face forming portion 21 which projects radially outward from the seal ring holding portion 21f in which the O-ring 22 is interposed on the outer peripheral surface.
e is provided on the inboard end surface of the sealed end surface forming portion 21e.
Since the outer peripheral edge forms the seal surface 21s located radially outward from the seal ring holding portion 21f, the in-machine gas pressure acts on the outer surface of the sealed end surface forming portion 21e and the seal surface 21s. It is possible to generate a closing force that is substantially balanced with the generated opening force. As a result, the non-contact shaft sealing state is stably maintained even when the internal gas pressure fluctuates.

Further, in the above, when the closing force is generated by the gas pressure in the machine, the communication hole 60 penetrating the seal ring 56 in the axial direction as in the above-described conventional example, or the hermetic seal is formed at the rear end side of the seal ring 56. Since there is no need to form the space E, the overall configuration becomes simpler. Further, since the in-machine gas penetrates only to the area on the front end side of the seal ring 21, the area exposed to the in-machine gas can be easily cleaned.

Further, in the above, the steam supply pipe 30 is provided in the first seal case 12 and
Through this, steam for cleaning can be supplied to the space behind the sealed end face forming portion 21e, so that even if the space shape of this region is made as small as possible, it is possible to clean the region reliably and easily. It is possible to make the whole more compact.

Although the specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various changes can be made within the scope of the present invention. For example, in the above-described embodiment, an example is described in which the O-ring 22 is used as a seal member for sealing the internal space between the seal ring 21 and the first seal case 12. It is possible to constitute the above-mentioned sealing member with another organic elastic member having a secondary sealing function. Further, as this sealing member, for example, a plurality of arc-shaped sealing rings, and winding around the outer periphery of these sealing rings It is also possible to employ a segment seal or the like including a circular spring that tightens these seal rings as a whole in a circular shape.

In the above embodiment, the stirrer operated by introducing a predetermined atmospheric gas into the machine has been described as an example of the shaft sealed device. However, for example, a state in which a liquid component is contained in the machine gas. The shaft-sealed device operated by
The present invention can be applied to a non-contact type shaft sealing device provided in another shaft sealed device that is operated by introducing a liquid into the machine.

[0047]

As described above, in the non-contact type shaft sealing device of the present invention, the seal ring holding portion in which the seal member for sealing the space inside the machine is interposed in the end region inside the machine in the seal ring. A sealing end face forming portion protruding radially outward, and forming a sealing surface on the inboard end face of the sealing end face forming portion, the outer peripheral edge of which is located radially outward from the interposition position of the sealing member. Therefore, a closing force against the opening force generated by the internal pressure acting on the sealing surface is generated by the internal pressure acting on the outer end face of the sealed end face forming portion. Thereby, even if the internal pressure fluctuates, the non-contact shaft sealing state can be stably maintained.

In addition, in the above, there is no need to form a communication hole penetrating the seal ring in the axial direction or a closed space outside the seal ring, so that the overall configuration can be simplified. Further, for example, since the in-machine gas only enters the area on the front end side of the seal ring, the area exposed to the in-machine gas can be easily cleaned.

The non-contact type shaft sealing device according to the present invention provides a cleaning fluid supply hole for supplying a cleaning fluid to the space between the outer end face of the sealing end face forming portion and the seal case. Since the shape of the space between the outer end face of the sealed end face forming portion and the seal case is reduced,
This area can be easily cleaned, and it is not necessary to form this area with an excessively large space shape, so that the entire structure can be made more compact.

[Brief description of the drawings]

FIG. 1 shows a non-contact type shaft sealing device according to an embodiment of the present invention. FIG. 1 (a) is a half-sectional view showing a configuration of an arrangement area of a seal ring in the device, and FIG. FIG. 4 is an explanatory diagram showing the axial pressing force on the seal ring, and FIG. 3C is an explanatory diagram showing a state where the axial pressing force is balanced.

FIG. 2 is a half cross-sectional view showing the entire configuration of the above device.

3A and 3B show a conventional non-contact type shaft sealing device, in which FIG. 3A is a half sectional view showing a configuration of an arrangement area of a seal ring, and FIG. FIG. 3C is an explanatory diagram showing the pressing force, and FIG. 3C is an explanatory diagram showing a state where the axial pressing force is balanced.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Non-contact type shaft sealing device 2 Rotating shaft 3 Housing 5 Rotating ring 5s Seal surface 12 First seal case 12a Gas supply hole 12b Steam supply hole (fluid supply hole for cleaning) 21 Seal ring 21b Air supply hole 21e Sealed end face forming portion 21f Seal ring holding portion 21s Seal surface 22 O-ring (seal member) 25 Spring (biasing means)

Continuation of the front page (56) References JP-A-5-164249 (JP, A) JP-A-10-281300 (JP, A) JP-A-9-273636 (JP, A) (58) Fields investigated (Int) .Cl. ⁷ , DB name) F16J 15/34

Claims (1)

(57) [Claims] 1. A rotating ring provided on a rotating shaft of a shaft-sealed device, a seal case fixed to a housing of the shaft-sealed device, and a rotating ring between the seal case and the rotating shaft from the outside of the machine. A seal ring disposed axially movably so as to face the axial direction, and a seal member interposed between the seal ring and the seal case to seal a space inside the machine,
Biasing means for pressing the seal ring toward the rotating ring, and supplying a barrier gas between the sealing surfaces of the sealing ring and the rotating ring facing each other through an air supply hole formed in the sealing ring to provide a seal between the sealing surfaces. What is claimed is: 1. A non-contact type shaft sealing device formed so as to seal a shaft, wherein said seal ring has a seal ring holding portion internally fitted in said seal case to hold said seal ring in said seal case. A sealing end face forming portion protruding radially outward from the seal ring holding portion in an inboard end region with respect to the seal ring holding portion, the seal member is interposed on the outer peripheral surface of the seal ring holding portion, and the sealing end face formation is performed. The seal surface is formed on the inboard end face of the portion so that the outer peripheral edge thereof is located radially outward from the seal ring holding portion. Non-contact type shaft sealing device, characterized in that to form a cleaning fluid supply hole for supplying the fluid for cleaning the space between the outboard end face and the seal case.