JP6888976B2 - Shaft sealing device and rotating machine - Google Patents

Description

The present invention relates to a shaft sealing device and a rotating machine.

Rotating machines such as gas turbines and steam turbines are provided with a shaft seal device that reduces the amount of leakage of the working fluid flowing from the high pressure side to the low pressure side around the rotor.

Patent Document 1 describes a seal member main body provided on the radial outer side of the rotor and movably provided in the radial direction, and a movable seal member having an elastic body for urging the seal member main body toward the radial outer side. A shaft sealing device provided is disclosed.

In the shaft sealing device having such a configuration, the sealing member main body is urged radially outward by the elastic body when the rotating machine is started and stopped, and the sealing gap between the rotor and the movable sealing member is sufficiently sufficient. Secured.

On the other hand, when the rotating machine is operated, the working fluid on the high pressure side (for example, working steam) wraps around the back surface on the radial outer side of the sealing member body, so that the back surface pressure acts on the sealing member body. This back pressure displaces the sealing member body inward in the radial direction against the urging force of the elastic body.

Japanese Unexamined Patent Publication No. 2003-65076

By the way, in the shaft sealing device having the above configuration, when the working fluid on the high pressure side wraps around the back surface of the sealing member main body at the start of operation of the rotating machine, the sealing is performed by the back pressure acting on the back surface of the sealing member main body. It is preferable that the member body is rapidly displaced inward in the radial direction.
That is, it is preferable that a large back pressure is applied when the working fluid on the high pressure side wraps around the back surface of the seal member main body at the start of operation of the rotating machine.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a shaft sealing device capable of enhancing the operability of a movable sealing member, and a rotating machine.

In order to solve the above problems, the shaft sealing device according to one aspect of the present invention is provided between the rotor and the stator surrounding the rotor, and the space between the rotor and the stator is formed in the direction of the central axis of the rotor. In the shaft sealing device including a movable sealing member, which is divided into a high pressure side region through which the high pressure fluid flows and a low pressure side region through which the low pressure fluid flows, the movable sealing member is arranged on the inner peripheral side of the stator. A housing fixed to the stator, a seal member main body facing the outer peripheral surface of the rotor with a part accommodated in the housing with a gap interposed therebetween, and the seal. The movable seal member includes an elastic member that urges the member body to the outside in the radial direction of the rotor, and the movable seal member is formed on the end face side of the end portion of the seal member body arranged in the circumferential direction of the rotor. A cavity that is recessed inward in the circumferential direction of the rotor and a communication portion that communicates the cavity with the low-pressure side region are provided, and the depth of the cavity in the circumferential direction is determined by the housing and the above. in flown the high pressure fluid is said sealing member is capable of depth to increase relatively the back pressure on the body between the sealing member main body, and are within the range of not less 10 mm.

According to the present invention, in the seal member main body, a cavity formed on the end face side of an end portion arranged in the circumferential direction of the rotor and recessed toward the inside in the circumferential direction of the rotor, and a cavity and a low pressure side region. By having a communication portion for communicating with each other, it is possible to introduce a low-pressure fluid flowing in the low-pressure side region into the cavity through the communication portion and fill the inside of the cavity with the low-pressure fluid.

As a result, at the start of operation of the rotating machine, even if a high-pressure fluid flows into the cavity, the pressure inside the cavity is maintained at a low pressure, so it is possible to reduce the force of the fluid applied to the end face of the sealing member body. Become.

The back pressure received by the seal member body is a force acting in the opposite direction of the fluid force received by the end face of the seal member body. Therefore, by reducing the force of the fluid received by the end face of the seal member body, it is possible to relatively increase the back pressure received by the seal member body.
In this way, by relatively increasing the back pressure received by the seal member main body, the operability of the movable seal member (particularly, the operability of the movable seal member at the start of operation of the rotating machine) can be improved.

Further, in the shaft sealing device according to one aspect of the present invention, a fixed sealing member is included, and an end surface of the movable sealing member is provided between the bottom surface of the cavity and the end surface of the fixed sealing member facing the bottom surface. It may have an auxiliary urging member that urges the fixed seal member and the end surface of the fixed seal member in a direction that separates them from each other.

By having the auxiliary urging member having the above configuration, it is possible to reduce the pressure generated when the end face of the seal member main body and the end face of the fixed seal member face each other by the urging force of the auxiliary urging member. Therefore, the posture of the movable seal member can be stably maintained.

Further, in the shaft sealing device according to one aspect of the present invention, the sealing member main body includes a pressure receiving portion arranged inside the housing with the gap interposed therebetween, and a base portion arranged outside the housing. The housing includes a connecting portion that connects the pressure receiving portion and the base portion, and the housing is said to be formed when the high-pressure fluid is introduced into the gap and the sealing member main body moves in the central axis direction of the stator. It may have a contact surface to which a part of the connecting portion is in contact.

In this way, the housing is provided with a contact surface to which a part of the connection portion is brought into contact when moving in the central axis direction of the stator, so that a part of the connection portion and the contact surface of the stator are provided with each other. Friction force is generated.
However, as described above, by increasing the back pressure applied to the seal member main body, the influence of the frictional force can be reduced, so that the operability of the movable seal member (particularly, the start of operation of the rotating machine) The operability of the movable seal member at the time) can be improved.

The rotary machine according to one aspect of the present invention may include the shaft sealing device.

In this way, by including the shaft sealing device described above, it is possible to relatively increase the back pressure of the sealing member main body, so that the operability of the movable sealing member (particularly at the start of operation of the rotating machine) The operability of the movable seal member) can be improved.

According to the present invention, the operability of the movable seal member can be enhanced.

It is a figure which looked at the main part of the rotary machine which concerns on 1st Embodiment of this invention from the central axis direction of a rotor. It is sectional drawing in the X-ray direction of the shaft sealing apparatus shown in FIG. It is sectional drawing which shows typically the initial state which the back surface pressure was applied to the movable seal member shown in FIG. FIG. 5 is a cross-sectional view schematically showing a state in which a back surface pressure is applied to the seal member main body shown in FIG. 2, the seal member main body is displaced toward the rotor side, and the seal member main body is in contact with the contact surface of the housing. It is a perspective view which shows the schematic structure of the end part of the movable seal member shown in FIG. It is a figure for demonstrating the relationship between the end face of a movable seal member, and a rotor. It is a figure which shows typically the main part of the rotary machine which concerns on 2nd Embodiment of this invention.

Hereinafter, embodiments to which the present invention has been applied will be described in detail with reference to the drawings. The drawings used in the following description are for explaining the configuration of the embodiment of the present invention, and the size, thickness, dimensions, etc. of the illustrated parts may differ from the actual dimensional relations of the steam turbine. There is.

(First Embodiment)
FIG. 1 is a view of the main part of the rotating machine according to the first embodiment of the present invention as viewed from the direction of the central axis of the rotor. In FIG. 1, only the rotor is shown in cross section. In FIG. 1, Dc is the circumferential direction of the rotor 102 (hereinafter, referred to as “circumferential direction Dc”), Ps is the end face pressure Ps received by the end face 21s of the circumferential end of the movable seal member 20, and Ph is the movable seal member 20. The back pressure applied and acting on the side opposite to the end face pressure Ps (hereinafter referred to as "back pressure Ph"), M is the moving direction of the sealing member main body 21 (hereinafter referred to as "M direction"), and S1 is a low pressure fluid (low pressure). The region where the working fluid (hereinafter referred to as “low pressure side region S1”) exists, and S2 is the region where the high pressure fluid (high pressure working fluid) having a higher pressure than the low pressure fluid exists (hereinafter referred to as “high pressure side region S2”). Are shown respectively. In FIG. 1, the plurality of seal fins 26 shown in FIG. 2 are not shown.
Further, in FIG. 1, as an example of the shaft sealing device 1, a case where the shaft sealing device 1 is composed of two fixed sealing members 10 and two movable sealing members 20 will be described as an example.

FIG. 2 is a cross-sectional view of the shaft sealing device shown in FIG. 1 in the XX line direction. In FIG. 2, the same components as those of the structure shown in FIG. 1 are designated by the same reference numerals.
FIG. 3 is a cross-sectional view schematically showing an initial state in which a back surface pressure is applied to the movable seal member shown in FIG. In FIG. 3, F is an elastic force due to the elastic member 30 (hereinafter, referred to as “elastic force F”), and f is that the first surface 24f of the connecting portion 24 is in contact with the contact surface 108a of the protruding portion 108. It is a frictional force generated in (hereinafter, referred to as "friction force f"). The elastic force F and the frictional force f are forces acting in the radial direction Dr of the rotor 102. In FIG. 3, the same components as those of the structures shown in FIGS. 1 and 2 are designated by the same reference numerals.

FIG. 4 is a cross section schematically showing a state in which a back pressure is applied to the seal member main body shown in FIG. 2, the seal member main body is displaced toward the rotor side, and the seal member main body is in contact with the contact surface of the stator. It is a figure. In FIG. 4, the same components as those of the structures shown in FIGS. 1 to 3 are designated by the same reference numerals.
FIG. 5 is a perspective view showing a schematic configuration of an end portion of the movable seal shown in FIG. In FIG. 5, the same components as those of the structures shown in FIGS. 1 to 4 are designated by the same reference numerals.
FIG. 6 is a diagram for explaining the relationship between the end face of the movable seal member and the rotor. In FIG. 6, the rotor is illustrated in cross section. Further, in FIG. 6, the same components as those of the structures shown in FIGS. 1 to 5 are designated by the same reference numerals.
In the first embodiment, an abradable seal structure will be described as an example of the seal structure.

With reference to FIGS. 1 to 5, the rotary machine 100 of the first embodiment includes a rotor 102, a stator 103, and a shaft seal device 1 including a fixed seal member 10 and a movable seal member 20.

The rotor 102 extends in a predetermined direction. The shape of the rotor 102 can be, for example, a cylindrical shape. The rotor 102 has an outer peripheral surface 102a. A plurality of seal fins 26 are provided on the outer peripheral surface 102a of the rotor 102 facing the seal body 25 constituting the movable seal member 20. The plurality of seal fins 26 are integrally formed with the rotor 102.

Further, a plurality of seal fins (not shown) are provided on the outer peripheral surface 102a of the rotor 102 facing the seal body (not shown) constituting the fixed seal member 10. These plurality of seal fins are integrally formed with the rotor 102.

The stator 103 is attached to the passenger compartment (not shown) of the rotary machine 100. The stator 103 is provided on the outside of the rotor 102. The inner peripheral surface 103a of the stator 103 faces the outer peripheral surface 102a of the rotor 102 in a state of being separated from the rotor 102. An annular space is formed between the stator 103 and the rotor 102.

The shaft sealing device 1 is provided in an annular space between the rotor 102 and the stator 103. The shaft sealing device 1 has a ring shape. The shaft sealing device 1 divides the annular space formed between the rotor 102 and the stator 103 into a low pressure side region S1 and a high pressure side region S2.

The low-pressure side region S1 and the high-pressure side region S2 are arranged in the central axial direction Da of the rotor 102. The low pressure side region S1 is arranged on one side of the shaft sealing device 1. The high pressure side region S2 is arranged on the other side of the shaft sealing device 1.
The low pressure side region S1 is a region through which a low pressure fluid (low pressure working fluid) flows. The high-pressure side region S2 is a region in which a high-pressure fluid (high-pressure working fluid) having a higher pressure than the low-pressure fluid flowing through the low-pressure side region S1 flows.

The shaft seal device 1 includes two fixed seal members 10 and two movable seal members 20 (seal members). The two movable seal members 20 and the two fixed seal members 10 have an arc shape. The two movable seal members 20 are arranged to face each other via the rotor 102.

The fixed seal member 10 is arranged between the two movable seal members 20. A pair of upper members 10A and lower members 10B are arranged on the left and right sides of the rotor 2, respectively. The paired upper member 10A and lower member 10B are joined by a mating surface 10b.
The length of the movable seal member 20 in the circumferential direction of the rotor 102 is configured to be longer than the length of the fixed seal member 10 in the circumferential direction Dc of the rotor 102.
The angle formed by the two straight lines connecting both ends of the fixed seal member 10 and the central axis of the rotor 102 can be, for example, 60 °. In this case, the angle formed by the two straight lines connecting both ends of the movable seal member 20 and the central axis of the rotor 102 can be, for example, 120 °.

The fixed seal member 10 has a seal body (not shown) having a plurality of grooves (not shown) facing the plurality of seal fins (not shown) provided on the outer peripheral surface 102a of the rotor 102. The fixed seal member 10 exhibits a labyrinth effect by inserting seal fins into a plurality of grooves. When a steam turbine is used as the rotary machine 100, the fixed seal member 10 suppresses steam leakage.

The fixed seal member 10 is elastically supported from the back surface by a leaf spring or the like. The fixed seal member 10 is basically an immovable seal member that can be displaced outward in the radial direction when it comes into contact with the rotor 102, and does not move according to the operating state of the rotating machine 100. ..

The movable seal member 20 is arranged so as to face each other in the vertical direction with the rotor 102 interposed therebetween. The movable seal member 20 is an arc-shaped member and has two ends. The movable seal member 20 includes a housing 104, a seal member main body 21, an elastic member 30, and a seal body 25.

The housing 104 is fixed to the inner peripheral surface 103a of the stator 103. A ring-shaped groove 105 is formed on the inner peripheral surface 104f side of the housing 104. A part of the seal member main body 21 is housed in the ring-shaped groove 105 with the gap 106 interposed therebetween.
The housing 104 has a pair of protrusions 108 that narrow the opening width of the end portion of the groove 105 located on the inner peripheral surface 104f side of the housing 104.

The pair of protrusions 108 are arranged so as to face each other in the central axis direction Da of the rotor 102. The pair of projecting portions 108 are projecting portions for preventing the seal member main body 21 from falling out of the housing 104.
The protrusion 108 has a contact surface 108a orthogonal to the central axial direction Da of the rotor 102. The contact surface 108a is a surface on which the connection portion 24 of the seal member main body 21 is in contact. When a part of the connecting portion 24 comes into contact with the contact surface 108a, a frictional force is generated.

The seal member main body 21 is a member having an arc shape, and has a pressure receiving portion 22, a base portion 23, and a connecting portion 24.

The pressure receiving portion 22 is housed in a groove 105 formed in the housing 104. The width of the pressure receiving portion 22 in the central axial direction Da of the rotor 102 is configured to be narrower than the width of the groove 105 in the central axial direction Da of the rotor 102. Further, the thickness of the pressure receiving portion 22 in the radial direction Dr of the rotor 102 is configured to be smaller than the width of the groove 105 in the radial direction Dr of the rotor 102.

The pressure receiving portion 22 has a pressure receiving surface 22f arranged on the side opposite to the side to which the connecting portion 24 is connected. The pressure receiving surface 22f is a surface to which the pressure of the fluid is applied. The pressure receiving surface 22f faces the inner surface of the groove 105 (the surface orthogonal to the radial direction Dr of the rotor 102) in the radial direction Dr of the rotor 102.
The pressure receiving portion 22 having the above configuration is configured to be displaceable in the groove 105 in the central axial direction Da and the radial direction Dr of the rotor 102.

The base portion 23 is arranged closer to the rotor 102 than the inner peripheral surface 104f of the housing 104. The width of the base portion 23 in the central axial direction Da of the rotor 102 is configured to be larger than the groove width between the pair of protruding portions 108. The base portion 23 has an inner peripheral surface 23a facing the plurality of seal fins 26.

The connecting portion 24 is arranged between the pressure receiving portion 22 and the base portion 23. The connecting portion 24 connects the pressure receiving portion 22 and the base portion 23. The connecting portion 24 has first and second surfaces 24f and 24g arranged in the central axial direction Da of the rotor 102.

The first surface 24f is a surface facing the contact surface 108a of the protrusion 108 arranged in the low pressure side region S1. The second surface 24g is a surface facing the protrusion 108 arranged in the high pressure side region S2.
The width of the connecting portion 24 in the central axial direction Da of the rotor 102 is configured to be narrower than the groove width between the pair of protruding portions 108. The connecting portion 24 faces the contact surface 108a of the protruding portion 108.

When the rotary machine 100 is started and stopped, the seal member main body 21 is separated from the rotor 102 in the radial direction. As a result, the gap between the movable seal member 20 and the rotor 102 becomes large.
During the rated operation of the rotary machine 100, the seal member main body 21 moves in the M direction. As a result, the gap between the movable seal member 20 and the rotor 102 is narrowed.

The seal body 25 is provided so as to cover the inner peripheral surface 23a of the base portion 23. A plurality of grooves into which the seal fins 26 can be inserted are formed in a portion of the seal body 25 facing the plurality of seal fins 26.

The elastic member 30 is provided so as to connect the inner surface of the groove 105 and the pressure receiving surface 22f of the pressure receiving portion 22. The elastic member 30 urges the movable seal member 20 to the outside of the rotor 102 in the radial direction Dr. As the elastic member 30, for example, a disc spring can be used. Instead of the disc spring, a leaf spring, a metal bellows, or the like may be used as the elastic member 30.

Here, the operation of the movable seal member 20 at the time of starting, stopping, and rated operation of the rotating machine 100 will be described.
When the rotary machine 100 is started and stopped, the seal member main body 21 is pulled out of the radial Dr of the rotor 102 by the elastic force F of the elastic member 30. As a result, the gap formed between the seal body 25 and the rotor 102 is widened.

On the other hand, during the rated operation of the rotary machine 100, there is a difference in the pressure of the fluid (working fluid) between the low pressure side region S1 and the high pressure side region S2. The seal member main body 21 receives a thrust force F0 from the high pressure side region S2 toward the low pressure side region S1 due to the pressure difference between the low pressure side region S1 and the high pressure side region S2. As a result, the seal member main body 21 moves to the low pressure side region S1 side (in the case of FIG. 4, the right side of the movable seal member 20).

By moving the seal member main body 21 to the low pressure side region S1 side in this way, the first surface 24f of the connecting portion 24 is brought into contact with the contact surface 108a of the protruding portion 108. As a result, the gap 106 formed between the protruding portion 108 arranged on the high-voltage side region S2 side and the second surface 24g of the connecting portion 24 is widened.

Then, the high-pressure fluid existing in the high-pressure side region S2 flows between the groove 105 and the pressure receiving portion 22 through the gap 106 formed between the protruding portion 108 and the second surface 24g of the connecting portion 24, and the groove The pressure in 105 rises.
As a result, the pressure receiving surface 22f of the pressure receiving portion 22 is pressed inside the radial direction Dr of the rotor 102. Then, the back pressure Ph toward the inside of the radial Dr of the rotor 102 is applied to the pressure receiving surface 22f of the pressure receiving portion 22, and the seal member main body 21 is displaced to the inside of the radial Dr of the rotor 102. Then, when the seal fin 26 abuts in the groove of the seal body 25, the movable seal member 20 divides the high pressure side region S2 and the low pressure side region S1 to exhibit a sealing function.

Here, the configuration of the two end portions 20A (components of the end portions of the movable seal member 20) of the seal member main body 21 arranged in the circumferential direction Dc of the rotor 102 will be described.
The end portion 20A of the seal member main body 21 has an end surface 21s that abuts on the fixed seal member 10, a cavity 27, and a communication portion 28.

The cavities 27 are formed on the end face 21s side of the two end portions 20A of the seal member main body 21, respectively. The cavity 27 is provided in the central portion of the end surface 21s of the end portion 20A. The cavity 27 is recessed toward the inside of the circumferential direction Dc of the rotor 102. The cavity 27 is a recess for lowering the pressure state in the cavity 27 by introducing the low-pressure fluid existing in the low-pressure side region S1 through the communication portion 28. The bottom surface 27a of the cavity 27 is flat.

The depth d (depth from the end face 21s to the bottom surface 27a) of the cavity 27 with respect to the end face 21s is, for example, a depth at which the back pressure Ph can be relatively increased and is 10 mm or less. It should be within the range. Normally, when there is no cavity, the pressure state of this end face is dominated by high pressure, and this pressure causes the back pressure Ph to become relatively small.
Further, if the depth d of the cavity 27 is too shallow, it may be difficult to maintain the pressure state in the cavity 27 at a low pressure when the high-pressure fluid flows into the cavity 27. As a result, the end face pressure Ps applied to the end face 21s does not decrease so much, and the back surface pressure Ph may become relatively small.

On the other hand, if the depth d of the cavity 27 is deeper than 10 mm, it is necessary to increase the thickness of the seal member main body 21 in the radial direction Dr of the rotor 102, so that the size of the movable seal member 20 may increase. there were.
Therefore, by setting the depth d of the cavity 27 to a depth that allows the back pressure Ph to be relatively large and within a range of 10 mm or less, it is possible to suppress an increase in the size of the movable seal member 20. Above, the back pressure Ph can be relatively increased.

The communication portion 28 is provided on the end surface 21s side of the end portion 20A. The communication portion 28 is a groove capable of communicating the cavity 27 and the low pressure side region S1. The communication portion 28 is a path for guiding the low-pressure fluid existing in the low-pressure side region S1 into the cavity 27.

During the rated operation of the rotary machine 100, the back pressure Ph due to the high pressure fluid flowing into the groove 105 from the high pressure side region S2 acts on the movable seal member 20. On the other hand, the low pressure fluid existing in the low pressure side region S1 is introduced into the cavity 27 through the communication portion 28 into the two end portions 20A of the movable seal member 20.
As a result, the end face pressure Ps applied to the end faces 21s of the two end portions 20A is reduced as compared with the conventional movable seal member 20 which does not have the cavity 27 and the communication portion 28.

Further, the high-pressure fluid existing in the high-pressure side region S2 may flow into the cavity 27, but since the low-pressure fluid exists in the entire cavity 27, the pressure in the cavity 27 approaches the pressure of the low-pressure fluid. As a result, the pressure Ps applied to the end faces 21s of the two end portions 20A is dominated by the low pressure fluid in the cavity 27.
In this way, as the pressure Ps applied to the end surface 21s becomes smaller, the back pressure Ph acting on the pressure receiving surface 22f of the pressure receiving portion 22 becomes relatively large.

At this time, in order for the movable seal member 20 to be displaced inward in the radial direction Dr, it is necessary to satisfy the following equation (1).
{(Back pressure Ph) x (Pressure receiving area A of pressure receiving portion 22)}> (Elastic force F + friction force f of elastic member 30) ... (1)
The frictional force f here is obtained by multiplying the friction coefficient μ at the sliding portion between the first surface 24f of the connecting portion 24 and the contact surface 108a of the protruding portion 108 of the groove 105 by the thrust force F0.

As shown in the above equation (1), by providing the cavity 27 and increasing the back pressure Ph, the elastic force F outward of the radial Dr by the elastic member 30 and the contact between the first surface 24f and the protruding portion 108. The movable seal member 20 is likely to be displaced inward in the radial direction against the frictional force f between the surface 108a.

According to the shaft sealing device 1 of the first embodiment, the sealing member main body 21 is formed on the end surface 21s side of the end portion 20A arranged in the circumferential direction Dc of the rotor 102, and is formed on the peripheral direction Dc of the rotor 102. By having the cavity 27 recessed inward and the communication portion 28 for communicating the cavity 27 and the low pressure side region S1, the low pressure fluid flowing through the low pressure side region S1 is introduced into the cavity 27 through the communication portion 28. The cavity 27 can be filled with the low-pressure fluid.

As a result, at the start of operation of the rotary machine 100, the pressure in the cavity 27 is maintained at a low pressure even when the high-pressure fluid flows into the cavity 27 through the gap 106 formed between the groove 105 and the pressure receiving portion 22. Therefore, it is possible to reduce the force of the fluid applied to the end surface 21s of the seal member main body 21.

The back pressure Ph applied to the movable seal member 20 is a force acting in the opposite direction of the fluid force received by the end surface 21s of the seal member main body 21. Therefore, by reducing the force of the fluid received by the end surface 21s of the movable seal member 20, the back pressure Ph received by the seal member main body 21 can be relatively increased.
In this way, by increasing the back pressure Ph received by the seal member main body 21, the operability of the movable seal member 20 (particularly, the operability of the movable seal member 20 at the start of operation of the rotary machine 100) can be improved. it can.

Further, when the sealing member main body 21 moves along the central axial direction Da due to the introduction of the high-pressure fluid and the first surface 24f of the connecting portion 24 comes into contact with the contact surface 108a of the protruding portion 108, the first surface becomes the first. A frictional force f is generated between the surface 24f and the contact surface 108a.
On the other hand, as described above, the first method is to introduce a low pressure fluid into the cavity 27 to reduce the back pressure Ps received by the end 20A of the movable seal member 20 and relatively increase the back pressure Ph. The movable seal member 20 can be efficiently displaced against the frictional force f generated between the surface 24f and the contact surface 108a.

Since the rotary machine 100 including the movable seal member 20 having the above-described configuration can relatively increase the back pressure Ph received by the seal member main body 21, the operability of the movable seal member 20 (particularly, rotation). The operability of the movable seal member 20 at the start of operation of the machine 100) can be enhanced.

(Second Embodiment)
FIG. 7 is a diagram schematically showing a main part of a rotary machine according to a second embodiment of the present invention. In FIG. 7, the same components as those of the structures shown in FIGS. 1 to 6 are designated by the same reference numerals. Further, in FIG. 7, only the movable seal member is shown in cross section.

Here, the rotary machine of the second embodiment will be described with reference to FIG. 7.
An auxiliary urging member having an urging force in a direction in which the bottom surface 27a and the end surface 10a are separated from each other between the bottom surface 27a of the cavity 27 of the movable seal member 20 and the end surface 10a of the fixed seal member 10 facing the bottom surface 27a. 50 may be provided.
As the auxiliary urging member 50, for example, a coil spring can be used. As the auxiliary urging member 50, for example, a member having a spring force sufficiently smaller than the value of the fluid force existing around the auxiliary urging member 50 may be used.

According to the rotary machine of the second embodiment, the bottom surface 27a (or the end surface 21s) and the end surface 10a are placed between the bottom surface 27a of the cavity 27 and the end surface 10a of the fixed seal member 10 facing the bottom surface 27a. By providing the auxiliary urging member 50 having an urging force in the direction of separation, the pressure generated when the end surface 21s of the movable seal member 20 and the end surface 10a of the fixed seal member 10 face each other is released to the auxiliary urging member 50. It is possible to reduce it by the urging force of. As a result, the posture of the movable seal member 20 can be stably maintained.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various aspects are described within the scope of the claims of the present invention. It can be transformed and changed.

In the first and second embodiments, an abrasive seal structure has been described as an example of the seal structure, but for example, a seal structure other than the abrasive seal structure (for example, a labyrinth seal structure) may also be used. It is applicable and the same effect as that of the first and second embodiments can be obtained.

The present invention can be applied to a shaft sealing device and a rotating machine.

1 ... Shaft sealing device, 10 ... Fixed sealing member, 10a, 21s ... End face, 10b ... Mating surface 10A ... Upper member, 10B ... Lower member, 20 ... Movable sealing member, 20A ... End, 21 ... Sealing member body, 22 ... Pressure receiving part, 22f ... Pressure receiving surface, 23 ... Base part, 23a ... Inner peripheral surface, 24 ... Connecting part, 24f ... First surface, 24g ... Second surface, 25 ... Seal body, 26 ... Seal fin, 27 ... Cavity, 27a ... Bottom surface, 28 ... Communication part, 30 ... Elastic member, 50 ... Auxiliary urging member, 100 ... Rotating machine, 102 ... Rotor, 102a ... Outer surface, 103 ... Stator, 103a, 104f ... Inner peripheral surface , 104 ... housing, 105 ... groove, 106 ... gap, 108 ... protrusion, Da ... central axis direction, Dc ... circumferential direction, Dr ... radial direction, F ... urging force, F0 ... thrust force, M ... direction, Ph ... Back surface pressure, Ps ... end face pressure, S1 ... low pressure side region, S2 ... high pressure side region, f ... frictional force

Claims (4)

It is provided between the rotor and the stator surrounding the rotor, and the space between the rotor and the stator is divided into a high-pressure side region through which the high-pressure fluid flows and a low-pressure side region through which the low-pressure fluid flows in the direction of the central axis of the rotor. It is a shaft sealing device that is separated and includes a movable sealing member.
The movable seal member is arranged on the inner peripheral side of the stator, and has a housing fixed to the stator and a housing.
A seal member main body that is partially housed in the housing with a gap interposed therebetween and faces the outer peripheral surface of the rotor with the gap interposed therebetween.
An elastic member that urges the seal member body to the outside in the radial direction of the rotor, and
With
The movable seal member includes a cavity formed on the end face side of an end portion of the seal member body arranged in the circumferential direction of the rotor and recessed inward in the circumferential direction of the rotor.
A communication portion that communicates the cavity with the low pressure side region,
With
Depth in the circumferential direction of the cavity is in the housing and the sealing member main body depth that can the high pressure fluid flowing to relatively large back pressure on the sealing member main body between the of And a shaft seal device within a range of 10 mm or less. Includes fixed seal member,
An auxiliary urging member is provided between the bottom surface of the cavity and the end surface of the fixed seal member facing the bottom surface in a direction in which the end surface of the movable seal member and the end surface of the fixed seal member are separated from each other. The shaft sealing device according to claim 1. The seal member main body includes a pressure receiving portion arranged inside the housing with the gap interposed therebetween, a base portion arranged outside the housing, and a connecting portion connecting the pressure receiving portion and the base portion. Including
Claim 1 has a contact surface in which a part of the connection portion is brought into contact with the housing when the high-pressure fluid is introduced into the gap and the sealing member main body moves in the central axis direction of the stator. Or the shaft sealing device according to 2. A rotating machine including the shaft sealing device according to any one of claims 1 to 3.

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