WO2018142855A1

WO2018142855A1 - Shaft sealing apparatus and vertical shaft pump provided with same

Info

Publication number: WO2018142855A1
Application number: PCT/JP2018/000281
Authority: WO
Inventors: 康川井; 廣川　一人; 平田　和也
Original assignee: 株式会社荏原製作所
Priority date: 2017-02-03
Filing date: 2018-01-10
Publication date: 2018-08-09
Also published as: JP2018123947A

Abstract

The present invention pertains to a shaft sealing apparatus that prevents leakage of a liquid from the shaft penetration part of a container penetrated by a rotary shaft. A shaft sealing apparatus (30) is provided with: a seal casing (70) that has a plurality of casing structures (33, 53) arranged along the axial direction of a rotary shaft (6); a plurality of seal chambers (33a, 53a) that are formed inside the respective casing structures; and a plurality of disk-shaped seal bodies (51) that have annular surfaces (31a, 51a) vertical to the shaft center of the rotary shaft, that are respectively housed in the seal chambers, and that rotate integrally with the rotary shaft. The casing structure have through-holes (35a, 55a) through which the rotary shaft passes and which are connected with the seal chambers, and the inner surfaces of the casing structures opposed to the annular surfaces of the seal bodies are planes vertical to the shaft center of the rotary shaft.

Description

Shaft seal device and vertical shaft pump equipped with the shaft seal device

The present invention relates to a shaft seal device that prevents liquid from leaking from a shaft penetrating portion of a container through which a rotating shaft passes. The present invention also relates to a vertical shaft pump provided with this shaft seal device.

Generally, a shaft seal device is known that is fixed to a container that separates a high-pressure fluid and a low-pressure fluid and seals a shaft penetration portion of a rotating shaft that extends through the container. For example, the rotating shaft that rotates the impeller of the vertical shaft extends through the pump casing, and the shaft penetrating portion is provided by a shaft sealing device so that liquid does not leak from the shaft penetrating portion through which the rotating shaft passes. Sealed. In the vertical pump, the container is a pump casing, the high-pressure fluid is a liquid flowing inside the pump casing, and the low-pressure fluid is the atmosphere outside the pump casing. Such a shaft seal device generally employs a seal mechanism such as a gland packing, a mechanical seal, or a floating seal.

¡Gland packing is in contact with the outer peripheral surface of the rotating shaft and prevents liquid leakage by the contact pressure. The mechanical seal has a rotating ring that rotates integrally with the rotating shaft and a fixing ring that is fixed to a stationary member such as a housing. The rotating ring and the fixing ring maintain contact with each other to prevent liquid leakage. To do. The floating seal has a sleeve fixed to the outer peripheral surface of the rotating shaft, and a seal ring facing the sleeve. An extremely minute gap is formed between the seal ring and the sleeve, and only a minute amount of liquid is allowed to leak.

Since the gland packing is always in contact with the rotating shaft (this contact state is referred to as “sliding contact”), the gland packing gradually wears. Therefore, periodic maintenance or replacement of the gland packing is necessary. In addition, since the frictional heat is generated in the gland packing in sliding contact with the rotating shaft, it is necessary to cool the gland packing. If the liquid to be handled is fresh water, the gland packing can be cooled with that liquid. However, if the liquid contains a solid such as slurry, a separate one is provided so that the solid does not get caught between the gland packing and the rotating shaft. It is necessary to supply the liquid from the water injection device to the gland packing, or to surround the rotating shaft with a protective tube for preventing solids from entering.

∙ The rotating ring of the mechanical seal is always in sliding contact with the fixed ring, so the rotating ring and the fixed ring are gradually worn. Therefore, periodic maintenance or replacement of the rotating ring and the fixing ring is required. In addition, since frictional heat is generated due to the sliding contact between the rotating ring and the fixed ring, the mechanical seal needs an auxiliary facility for injecting a cooling flushing liquid. Further, since the contact surface between the rotating ring and the fixing ring is precisely finished, when the rotating ring and the fixing ring are maintained or exchanged, accurate assembly of the rotating ring and the fixing ring is required.

フローティング Unlike the gland packing and mechanical seal that make sliding contact, the floating seal has a minute gap formed between the seal ring and the sleeve, and is therefore a non-contact shaft seal device that does not include any components that make sliding contact. Therefore, the maintenance required by gland packing or mechanical seal is essentially unnecessary. However, the seal ring may come into contact with the sleeve when a whirling or vibration occurs on the rotating shaft. For this reason, in order to allow such a contact, it is necessary to use a highly hard material having high wear resistance for the seal ring and / or the sleeve, and the floating seal tends to be expensive. Further, since the floating seal allows a certain amount of liquid to pass through, the floating seal is not suitable for preventing leakage of liquid containing solid such as slurry. In the case of a floating seal, when the liquid to be handled is seawater, it is often impossible to use a high hardness material due to its corrosiveness.

Furthermore, when the shaft seal device has only one seal mechanism, the handled fluid may leak from the shaft seal device depending on the pressure of the fluid to be handled (for example, liquid in the pump casing of the vertical shaft pump). . More specifically, when the pressure of the fluid handled is very high, liquid may leak from the shaft seal device. When a shaft seal device in which a plurality of seal mechanisms are arranged in series is used, fluid can be prevented from leaking from the shaft seal device. However, when the number of seal mechanisms increases, the shaft seal device and its associated equipment increase in size, and the maintenance frequency and maintenance cost increase significantly. For example, the maintenance frequency and maintenance cost in the shaft seal device in which two floating seals are arranged in series are twice the maintenance frequency and maintenance cost in the shaft seal device in which one floating seal is arranged.

The present invention has been made in view of the above circumstances, and is capable of greatly reducing the maintenance frequency and supplying a liquid such as cooling water without leaking the fluid even when the pressure of the fluid to be handled is high. It is an object of the present invention to provide a shaft seal device that does not require additional equipment and that does not require special finishing of components. Moreover, an object of this invention is to provide the vertical shaft pump provided with this shaft seal device.

In order to achieve the above-described object, one aspect of the present invention is a shaft seal device that is fixed to a container that separates a high-pressure fluid and a low-pressure fluid and seals a shaft penetration portion of a rotary shaft that extends through the container. A seal casing having a plurality of casing structures disposed along an axial direction of the rotating shaft, a plurality of seal chambers formed inside each of the plurality of casing structures, and the plurality of seal chambers Each of the plurality of disc-shaped sealing bodies that rotate integrally with the rotation shaft and have an annular surface perpendicular to the axis of the rotation shaft, each of the plurality of casing structures. The inner surface of the casing structure that has a through hole that passes through the rotating shaft and communicates with the seal chamber, is opposed to the annular surface of the seal body, and forms the seal chamber, of A shaft seal device which is a plane perpendicular to the heart.

In a preferred aspect of the present invention, a plurality of radially extending grooves are formed on the annular surface of at least one of the plurality of seal bodies, and the width of the groove is outside the inner end of the groove. It is constant to the end.
In a preferred aspect of the present invention, a plurality of radially extending grooves are formed on the annular surface of at least one of the plurality of seal bodies, and the width of the grooves is directed toward the outer ends of the grooves. It is characterized by gradually increasing.

In a preferred aspect of the present invention, the through hole of the seal structure located on the uppermost side of the plurality of seal structures and the rotation above the seal body located on the uppermost side of the plurality of seal bodies. A non-contact type upper seal structure for sealing a gap with the shaft is further provided.
In a preferred aspect of the present invention, the upper seal structure is a labyrinth seal or a flat seal, and a leak cover is provided that is fixed to an upper portion of the seal casing so as to surround the upper seal structure. The cover is provided with an opening that communicates the internal space of the leak cover and the outside of the leak cover, and a leak pipe is connected to the opening.

According to a preferred aspect of the present invention, a through hole of a lowermost seal structure among the plurality of seal structures is provided below the lowermost seal body of the plurality of seal bodies. A non-contact type lower seal structure that seals a gap with the rotating shaft is further provided.
In a preferred aspect of the present invention, the lower seal structure is a Rabin rinse seal or a flat seal.
In a preferred aspect of the present invention, the seal casing is provided with at least one opening that communicates at least one of the plurality of seal chambers with the outside of the seal casing, and the opening includes a drain. A tube is connected.

Another aspect of the present invention is a shaft sealing device that is fixed to a container that separates a high-pressure fluid and a low-pressure fluid, and that seals a shaft penetration portion of a rotating shaft that extends through the container, the axial direction of the rotating shaft A seal casing having a plurality of casing structures disposed along the plurality of casing structures, a plurality of seal chambers formed inside each of the plurality of casing structures, and the rotation accommodated in each of the plurality of seal chambers A plurality of disc-shaped seal bodies that rotate integrally with a shaft, and each of the plurality of casing structures has a through-hole that communicates with the seal chamber while passing through the rotation shaft, The seal body has an upper surface that is inclined downward with respect to a plane perpendicular to the axis of the rotary shaft, and is opposed to the upper surface of the seal body and forms the seal chamber of the casing structure. The inner surface A shaft sealing device, characterized in that extending along the top surface of the serial seal member.
In a preferred aspect of the present invention, the upper surface of the seal body is curved.

Another aspect of the present invention includes an impeller, a rotating shaft to which the impeller is fixed, a pump casing that houses the impeller and has a shaft penetrating portion through which the rotating shaft passes, and the shaft penetrating portion. A shaft seal device for sealing the seal casing, wherein the shaft seal device has a plurality of casing structures disposed along an axial direction of the rotating shaft, and each of the plurality of casing structures. A plurality of seal chambers formed inside each of the plurality of seal chambers, and a plurality of disk-shaped members that are accommodated in each of the plurality of seal chambers, rotate integrally with the rotation shaft, and have an annular surface perpendicular to the axis of the rotation shaft Each of the plurality of casing structures has a through hole through which the rotating shaft passes and communicates with the seal chamber, and is opposed to the annular surface of the seal body, and Shape the sealing chamber An inner surface of said casing structure which is a vertical shaft pump, wherein the a plane perpendicular to the axis of the rotating shaft.

Another aspect of the present invention includes an impeller, a rotating shaft to which the impeller is fixed, a pump casing that houses the impeller and has a shaft penetrating portion through which the rotating shaft passes, and the shaft penetrating portion. A shaft seal device for sealing the seal casing, wherein the shaft seal device has a plurality of casing structures disposed along an axial direction of the rotating shaft, and each of the plurality of casing structures. A plurality of sealing chambers formed therein, and a plurality of disc-shaped sealing bodies that are housed in the plurality of sealing chambers and rotate integrally with the rotation shaft, respectively, and the plurality of casing structures Each of which has a through hole through which the rotary shaft passes and communicates with the seal chamber, and the seal body has an upper surface which is inclined downward with respect to a plane perpendicular to the axis of the rotary shaft. And said seal The inner surface of the casing structure of the opposing the annular surface, and to form the seal chamber is a vertical shaft pump, characterized in that extending along the top surface of the seal body.

According to the shaft seal device of the present invention, fluid is prevented from leaking from the shaft seal device by a plurality of seal bodies that are arranged in series in the axial direction of the rotation shaft and rotate integrally with the rotation shaft. Therefore, even when the pressure of the fluid to handle is high, the fluid leakage from the shaft seal device can be prevented. Furthermore, since this shaft seal device is a non-contact shaft seal device in which each seal body does not slidably contact other members, the seal body does not wear. Therefore, the maintenance frequency of the shaft seal device can be greatly reduced. In addition, since each sealing body exhibits a sealing function in a non-contact manner, the frictional heat generated in the liquid flowing on each sealing body is negligible compared to a shaft sealing device including constituent members that are in sliding contact with each other. In addition, it is not necessary to separately provide ancillary equipment for supplying liquid such as cooling water or flushing liquid to the shaft seal device. Further, unlike the mechanical seal, it is not necessary to precisely finish the surface of the constituent members such as the rotating ring and the fixed ring, and accurate assembly is not required.

FIG. 1 is a schematic diagram showing a vertical shaft pump provided with a shaft seal device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the shaft seal device shown in FIG. FIG. 3A is a top view showing an embodiment of the first seal body. 3B is a cross-sectional view taken along line AA in FIG. 3A. FIG. 4A is a top view showing another embodiment of the first seal body. 4B is a cross-sectional view taken along the line BB of FIG. 4A. FIG. 5A is a top view showing still another embodiment of the first seal body. 5B is a cross-sectional view taken along the line CC of FIG. 5A. FIG. 6A is a top view showing still another embodiment of the first seal body. 6B is a cross-sectional view taken along the line DD of FIG. 6A. FIG. 7 is a cross-sectional view of a shaft seal device according to another embodiment. FIG. 8 is a cross-sectional view showing a modification of the shaft seal device shown in FIG. FIG. 9 is a cross-sectional view of a shaft seal device according to still another embodiment. FIG. 10 is a cross-sectional view of a shaft seal device according to still another embodiment. FIG. 11 is a cross-sectional view of a shaft seal device according to yet another embodiment. FIG. 12 is a cross-sectional view of a shaft seal device according to still another embodiment.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic diagram showing a vertical shaft pump provided with a shaft seal device 30 according to an embodiment of the present invention. As shown in FIG. 1, the vertical shaft pump is connected to an impeller casing 1 having a suction bell mouth 1 a and a discharge bowl 1 b, a pumping pipe 3 for suspending the impeller casing 1 in a suction water tank 5, and an upper end of the pumping pipe 3. A discharge elbow pipe 4, an impeller 10 accommodated in the impeller casing 1, and a rotating shaft 6 to which the impeller 10 is fixed. The pumping pipe 3 extends downward through an insertion port 24 formed in the pump installation floor 22 at the upper part of the suction water tank 5, and is fixed to the pump installation floor 22 via an installation base 23 provided at the upper end of the pumping pipe 3. The The rotary shaft 6 extends in the vertical direction through the discharge elbow pipe 4, the pumping pipe 3, and the impeller casing 1. The pump casing 2 includes an impeller casing 1, a pumping pipe 3, and a discharge elbow pipe 4.

The suction bell mouth 1a opens downward, and the upper end of the suction bell mouth 1a is connected to the lower end of the discharge bowl 1b. The impeller 10 is fixed to the lower end of the rotating shaft 6, and the impeller 10 and the rotating shaft 6 rotate integrally. A plurality of guide vanes 14 are arranged above the impeller 10 (discharge side). These guide vanes 14 are fixed to the inner peripheral surface of the discharge bowl 1b. The rotating shaft 6 is rotatably supported by an outer bearing 11, an intermediate bearing 15, and an underwater bearing 12. The underwater bearing 12 is accommodated in the discharge bowl 1 b and is disposed above the impeller 10. The support member 7 that supports the underwater bearing 12 is fixed to the inner surface of the bowl bush 13, and the bowl bush 13 is supported by the impeller casing 1 via a guide vane 14. The outer bearing 11 is a rolling bearing such as a ball bearing or a sliding bearing, and the underwater bearing 12 and the intermediate bearing 15 are sliding bearings.

The rotary shaft 6 extends upward through the discharge elbow pipe 4 and is connected to a drive source 18. The drive source 18 is fixed on a gantry 19 fixed to the pump installation floor 22. During operation of the vertical pump, the impeller 10 is located below the liquid level in the suction water tank 5.

The vertical shaft pump transfers the liquid in the suction water tank 5 to the discharge water tank 100. That is, when the impeller 10 is rotated through the rotating shaft 6 by operating the drive source 18, the liquid in the suction water tank 5 is sucked from the suction bell mouth 1a, and the discharge bowl 1b, the pumping pipe 3, and the discharge elbow pipe. 4, and the discharge water tank 100 through the discharge pipe 20. The discharge pipe 20 extends from the discharge elbow pipe 4 to the discharge water tank 100. The liquid level of the discharge water tank 100 is located above the discharge elbow pipe 4. A gate valve 25 is arranged in the middle of the discharge pipe 20, and the gate valve 25 is opened during normal operation of the vertical shaft pump. When the vertical pump is stopped, the gate valve 25 is closed to prevent the liquid from flowing back from the discharge water tank 100 to the suction water tank 5 through the discharge pipe 20. Instead of the gate valve 25, a check valve may be provided. Further, a flap valve may be arranged at the discharge end of the discharge pipe 20.

As shown in FIG. 1, a shaft seal device 30 according to an embodiment of the present invention is disposed in a shaft penetrating portion where the rotating shaft 6 penetrates the discharge elbow pipe 4 of the pump casing 2. The shaft seal device 30 prevents liquid from leaking out of the vertical shaft pump. Hereinafter, the shaft seal device 30 will be described with reference to FIG.

The shaft seal device 30 is a vertical shaft pump as long as it is fixed to a container that separates the lower high-pressure fluid and the upper low-pressure fluid, and seals the shaft penetration portion of the rotating shaft that extends through the container. It can be applied to other than. In the vertical shaft pump, the container is the pump casing 2, the high-pressure fluid is a liquid flowing inside the pump casing 2, and the low-pressure fluid is the atmosphere outside the pump casing 2.

FIG. 2 is a cross-sectional view of the shaft seal device 30 according to an embodiment of the present invention. As shown in FIG. 2, the shaft seal device 30 is fixed on the shaft seal device mounting surface 4 a of the discharge elbow pipe 4 so as to close the through hole 4 b formed in the discharge elbow pipe 4. The rotating shaft 6 extends in the vertical direction through the through hole 4b. The shaft seal device 30 includes a plurality of (two in FIG. 2) disk-shaped

seal bodies

31 and 51 fixed to the rotary shaft 6 and a plurality (two in FIG. 2)

casing structures

33 and 53. And a sealing casing 70 having Inside the casing structure 33, a seal chamber 33a for accommodating the seal body 31 is formed. Inside the casing structure 53, a seal chamber 53a for accommodating the seal body 51 is formed. In the following description, the seal body 31 is referred to as a first seal body 31, the seal body 51 is referred to as a second seal body 51, the casing structure 33 is referred to as a first casing structure 33, and the casing structure 53 is referred to as a second. This is referred to as a casing structure 53. Further, a seal chamber 33a that is formed inside the first casing structure 33 and accommodates the first seal body 31 is referred to as a first seal chamber 33a, is formed inside the second casing structure 53, and is a second seal body. The seal chamber 53a that houses 51 is referred to as a second seal chamber 53a.

Since the rotation shaft 6 and the inner peripheral surface of the first seal body 31 (through holes 31b shown in FIGS. 3A and 3B described later) are in close contact with each other, the inner surfaces of the rotation shaft 6 and the first seal body 31 Liquid does not pass between the peripheral surfaces. Although not shown, the gap between the rotating shaft 6 and the inner peripheral surface of the first seal body 31 may be sealed with a seal member such as an O-ring. Similarly, the rotating shaft 6 and the inner peripheral surface of the second seal body 51 are in close contact with each other, so that no liquid passes between the rotating shaft 6 and the inner peripheral surface of the second seal body 51. A gap between the rotary shaft 6 and the inner peripheral surface of the second seal body 51 may be sealed with a seal member such as an O-ring. The center of the first seal body 31 and the center of the second seal body 51 coincide with the axis of the rotary shaft 6, and the two

seal bodies

31 and 51 rotate integrally with the rotary shaft 6.

The first casing structure 33 includes a first upper casing 35 having a first through hole 35a through which the rotary shaft 6 passes, and a first intermediate casing 36 that supports the first upper casing 35. The center line of the first through hole 35 a coincides with the axis of the rotation shaft 6. The first intermediate casing 36 has a cylindrical inner peripheral surface 36a. The center line of the inner peripheral surface 36 a coincides with the axis of the rotary shaft 6 and the center of the first seal body 31. The first intermediate casing 36 of the first casing structure 33 is sandwiched between the shaft sealing device mounting surface 4a of the discharge elbow pipe 4 and the first upper casing 35, and is attached to the first upper casing 35 and the shaft sealing device. It is fixed to the surface 4a. Thereby, a first seal chamber 33 a in which the first seal body 31 is accommodated is formed in the first casing structure 33.

In the present embodiment, the second casing structure 53 has the same configuration as the first casing structure 33. More specifically, the second casing structure 53 includes a second upper casing 55 having a second through hole 55a through which the rotary shaft 6 passes, and a second intermediate casing 56 that supports the second upper casing 55. . The center line of the second through hole 55 a coincides with the axis of the rotation shaft 6. The second intermediate casing 56 has a cylindrical inner peripheral surface 56a. The center line of the inner peripheral surface 56 a coincides with the axis of the rotary shaft 6 and the center of the second seal body 51.

The first casing structure 33 and the second casing structure 53 are arranged in series along the axial direction of the rotating shaft 6. In the present embodiment, the second intermediate casing 56 of the second casing structure 53 is sandwiched between the first upper casing 35 of the first casing structure 33 and the second upper casing 55 of the second casing structure 53. In this state, the first upper casing 35 and the second upper casing 55 are fixed. Thereby, a second seal chamber 53 a in which the second seal body 51 is accommodated is formed in the second casing structure 53. The second intermediate casing 56 of the second casing structure 53 shown in FIG. 2 has the same outer diameter as that of the first intermediate casing 36 of the first casing structure 33. The diameter of the peripheral surface 56 a is the same as the diameter of the inner peripheral surface 36 a of the first intermediate casing 36.

Although not shown, the second intermediate casing 56 of the second casing structure 33 may have an outer diameter different from the outer diameter of the first intermediate casing 36 of the first casing structure 33. Furthermore, the diameter of the inner peripheral surface 56 a of the second intermediate casing 56 may be different from the diameter of the inner peripheral surface 36 a of the first intermediate casing 36. In any case, the center line of the inner peripheral surface 56 a of the second intermediate casing 56 coincides with the axis of the rotary shaft 6 and the center of the second seal body 51.

Similarly in the embodiments shown in FIGS. 7, 8, 9, 10, 11, and 12 described later, the outer diameter of the second intermediate casing 56 of the second casing structure 33 is equal to the first casing structure. The outer diameter of the first intermediate casing 36 of the body 33 may be the same or different. Furthermore, the diameter of the inner peripheral surface 56a of the second intermediate casing 56 may be the same as or different from the diameter of the inner peripheral surface 36a of the first intermediate casing 36.

The through hole 4 b formed in the discharge elbow pipe 4 is formed along the inner peripheral surface 36 a of the first intermediate casing 36. That is, the through hole 4b has the same shape and the same size as the inner peripheral surface 36a of the first intermediate casing 36, and is connected to the inner peripheral surface 36a. The first seal chamber 33 a of the first casing structure 33 is open downward and communicates with the inside of the discharge elbow pipe 4 through a through hole 4 b formed in the discharge elbow pipe 4.

The first seal chamber 33 a is formed inside the first casing structure 33. More specifically, a first seal chamber 33 a is formed by the lower surface 35 b of the first upper casing 35 and the inner peripheral surface 36 a of the first intermediate casing 36. The first seal body 31 is fixed to the rotating shaft 6 in the first seal chamber 33a. The lower surface 35 b of the first upper casing 35 is a plane perpendicular to the axis of the rotation shaft 6. The inner peripheral surface 36 a of the first intermediate casing 36 is concentric with the outer peripheral surface of the rotating shaft 6. The first seal chamber 33a communicates with the first through hole 35a and is located below the first through hole 35a. The rotary shaft 6 extends in the vertical direction through the first seal chamber 33a and the first through hole 35a.

The first seal body 31 has an upper surface 31 a that is an annular surface perpendicular to the axis of the rotary shaft 6. The upper surface 31 a is configured as a surface that can give a suitable centrifugal force to the liquid flowing on the upper surface 31 a by the rotation of the first seal body 31. For example, a plurality of radially extending grooves 37 are formed on the upper surface 31a. The upper surface 31a of the first seal body 31 faces the lower surface 35b of the first upper casing 35, which is one of the inner surfaces of the first casing structure 33 forming the first seal chamber 33a, with a gap therebetween.

The clearance between the upper surface 31a of the first seal body 31 and the lower surface 35b of the first upper casing 35 is such that a necessary and sufficient centrifugal force field is generated in the clearance by the rotation of the first seal body 31. 31 is set in consideration of the rotational speed of 31, the diameter of the first seal body 31, and the kinematic viscosity of the liquid.

FIG. 3A is a top view showing an embodiment of the first seal body 31, and FIG. 3B is a cross-sectional view taken along the line AA of FIG. 3A. As shown in FIGS. 3A and 3B, a through hole 31 b into which the rotary shaft 6 is inserted is formed at the center of the first seal body 31. A plurality of grooves 37 extending radially from the inner peripheral surface of the first seal body 31 (that is, the through hole 31 b) to the outer peripheral surface of the first seal body 31 are formed on the upper surface 31 a of the first seal body 31. In the embodiment shown in FIG. 3A, 24 grooves 37 are formed, but the number of grooves 37 may be more or less than 24. In the embodiment shown in FIGS. 3A and 3B, the groove 37 extends linearly, and the width of the groove 37 is constant from the inner end to the outer end. Needless to say, since the upper surface 31 a of the first seal body 31 has the purpose of applying centrifugal force to the liquid flowing on the upper surface 31 a, the groove 37 is formed in the radial direction of the first seal body 31. May be inclined or may not extend linearly. Furthermore, the width of the groove 37 may not be constant.

A part of the liquid flowing through the discharge elbow pipe 4 (see FIG. 1) toward the discharge pipe 20 flows into the first seal chamber 33a of the first casing structure 33 through the through hole 4b. Further, the liquid passes through the groove 37 formed on the upper surface 31 a of the first seal body 31 and the gap between the upper surface 31 a of the first seal body 31 and the lower surface 35 b of the first upper casing 35, and thereby the first seal. It tends to flow in the radial direction of the first seal body 31 toward the center of the body 31 (that is, toward the rotating shaft 6). However, since a circumferential velocity component is generated in the liquid by the action of the groove 37 of the rotating first seal body 31, centrifugal force is generated in the liquid on the upper surface 31 a of the first seal body 31 and the liquid in the groove 37. To do. As a result, the liquid on the upper surface 31 a and the liquid in the groove 37 are pushed back toward the radially outer side of the first seal body 31. Furthermore, since the gap between the upper surface 31a of the first seal body 31 and the lower surface 35b of the first upper casing 35 has a suitable dimension, centrifugal force can be applied to the liquid present in the gap. As a result, a radially outward force is generated in all of the liquid existing in the gap between the upper surface 31 a of the first seal body 31 and the lower surface 35 b of the first upper casing 35 and the liquid existing in the groove 37. It will be.

Thus, since the centrifugal force field is formed in the gap between the first seal body 31 and the lower surface 35b of the first upper casing 35 by the rotation of the first seal body 31 having the groove 37, it exists in this gap. The static pressure of the liquid that rises increases outward in the radial direction of the upper surface 31 a of the first seal body 31. In the following, Expression (1) representing an inertial force (acceleration a) generated in a unit mass of liquid having a circumferential velocity component (angular velocity component) generated by the rotation of the first seal body 31 is shown.
a = rω ² (1)
Here, r is the radius of the first seal body 31, and ω is the angular velocity of the first seal body 31.

The inertial force (acceleration a) generated in a unit mass liquid having a circumferential velocity component (angular velocity component) generated by the rotation of the second seal body 51 described later can also be expressed by the above formula (1). In this case, r is the radius of the second seal body 51, and ω is the angular velocity of the second seal body 51.

Since the rotating first seal body 31 generates a circumferential velocity component in the liquid present below the first seal body 31, centrifugal force acts on the liquid present in the first seal chamber 33a, and the liquid Increased static pressure. When the difference between the static pressure of the liquid generated in the gap between the upper surface 31a of the first seal body 31 and the lower surface 35b of the first upper casing 35 and the static pressure of the liquid existing in the first seal chamber 33a is reduced. The liquid easily passes through the first through hole 35 a and leaks to the outside of the first casing structure 33. In the present embodiment, since the through-hole 4b formed in the discharge elbow pipe 4 is formed along the inner peripheral surface 36a of the first intermediate casing 36, the first seal chamber 33a is provided inside the discharge elbow pipe 4. It is open. Therefore, the volume of the liquid existing below the first seal body 31 is sufficiently larger than the volume of the gap formed by the upper surface 31a of the first seal body 31 and the lower surface 35b of the first upper casing 35. The circumferential velocity component of the liquid existing below the first seal body 31 can be sufficiently reduced. As a result, it can be assumed that the liquid present in the first seal chamber 33a is not affected by the rotation of the first seal body 31 or is influenced very slightly.

In order to prevent the liquid from passing through the first through hole 35 a of the first casing structure 33, that is, to prevent the liquid from leaking to the outside of the first casing structure 33, the rotating first seal body 31 causes the first seal body 31 to rotate. The static pressure of the liquid generated in the gap between the upper surface 31a of the first seal body 31 and the lower surface 35b of the first upper casing 35 is balanced with the static pressure of the liquid existing in the first seal chamber 33a. Larger than that.

However, when the pressure of the liquid flowing through the discharge elbow pipe 4 is very high, the liquid may leak from the first casing structure 33 through the first through hole 35a. Alternatively, since there are other components of the vertical shaft pump around the shaft seal device 30, the diameter of the first seal body 31 may not be set sufficiently large depending on various pumps and operating conditions. Also in this case, the liquid may leak from the first casing structure 33 through the first through hole 35a. Therefore, the seal casing 70 of the shaft seal device 30 includes a second casing structure 53 disposed on the upper side of the first casing structure 33, and the second seal body 51 is provided inside the second casing structure 53. A second seal chamber 53a for accommodating is formed. In the shaft seal device 30 shown in FIG. 2, the second casing structure 53 is directly fixed to the first upper casing 35 of the first casing structure 33. Although not shown, the second casing structure 53 may be fixed to the first upper casing 35 of the first casing structure 33 via a spacer member having a cylindrical shape.

In the present embodiment, the second casing structure 53 has the same configuration as the first casing structure 33, and the second seal body 51 has the same configuration as the first seal body 31. The liquid leaked from the first through hole 35a of the first casing structure 33 flows into the second seal chamber 53a formed inside the second casing structure 53, but is stored in the second seal chamber 53a and rotated. The second seal body 51 that rotates with the shaft 6 prevents liquid from leaking from the second casing structure 53 (that is, from the shaft seal device 30).

The second seal chamber 53 a is formed inside the second casing structure 53. More specifically, the second seal chamber 53a is formed by the lower surface 55b of the second upper casing 55, the inner peripheral surface 56a of the second intermediate casing 56, and the upper surface of the first upper casing 35 of the first casing structure 33. It is formed. The second seal body 51 is fixed to the rotating shaft 6 in the second seal chamber 53a. The lower surface 55 b of the second upper casing 55 is a plane perpendicular to the axis of the rotation shaft 6. The inner peripheral surface 56 a of the second intermediate casing 56 is concentric with the outer peripheral surface of the rotating shaft 6. The second seal chamber 53a communicates with the second through hole 55a and is located below the second through hole 55a. Further, the second seal chamber 53a communicates with the first seal chamber 33a via the first through hole 35a, and is located above the first through hole 35a. The rotating shaft 6 extends in the vertical direction through the second seal chamber 53a and the second through hole 55a.

As described above, the second seal body 51 of the present embodiment has the same configuration as the first seal body 31. More specifically, the second seal body 51 has a disk shape and has an upper surface 51 a that is an annular surface perpendicular to the axis of the rotating shaft 6. The upper surface 51 a is configured as a surface that can give a suitable centrifugal force to the liquid flowing on the upper surface 51 a by the rotation of the second seal body 51. A plurality of grooves 37 described with reference to FIGS. 3A and 3B are formed on the upper surface 51a of the second seal body 51 shown in FIG. The upper surface 51a of the second seal body 51 is opposed to the lower surface 55b of the second upper casing 55, which is one of the inner surfaces of the second casing structure 53 that forms the second seal chamber 53a, with a gap therebetween.

The gap between the upper surface 51 a of the second seal body 51 and the lower surface 55 b of the second upper casing 55 is such that a necessary and sufficient centrifugal force field is generated in the gap by the rotation of the second seal body 51. The rotational speed of 51, the diameter of the second seal body 51, and the kinematic viscosity of the liquid are set. The number of grooves 37 formed on the upper surface of the second seal body 51 can be arbitrarily set. Further, the groove 37 may extend linearly or may be inclined with respect to the radial direction of the second seal body 51. Or the groove | channel 37 does not need to extend linearly. Further, the width of the groove 37 may be constant or may not be constant.

The liquid that has passed through the first through hole 35 a of the first casing structure 33 flows into the second seal chamber 53 a of the second casing structure 53. Further, the liquid passes through the groove 37 formed on the upper surface 51 a of the second seal body 51 and the gap between the upper surface 31 a of the second seal body 51 and the lower surface 55 b of the second upper casing 55, and then the second seal. It tends to flow in the radial direction of the second seal body 51 toward the center of the body 51 (that is, toward the rotating shaft 6). However, since a circumferential velocity component is generated in the liquid by the action of the groove 37 of the rotating second seal body 51, centrifugal force is generated in the liquid on the upper surface 51 a of the second seal body 51 and the liquid in the groove 37. To do. As a result, the liquid on the upper surface 51 a of the second seal body 51 and the liquid in the groove 37 are pushed back toward the radially outer side of the second seal body 51. Furthermore, since the gap between the upper surface 51a of the second seal body 51 and the lower surface 55b of the second upper casing 55 has a suitable size, centrifugal force can be applied to the liquid present in the gap. As a result, a radially outward force is generated in all of the liquid existing in the gap between the upper surface 51 a of the second seal body 51 and the lower surface 55 b of the second upper casing 55 and the liquid existing in the groove 37. It will be. As described above, since the centrifugal force field is formed in the gap between the second seal body 51 and the lower surface 55b of the second upper casing 55 by the rotation of the second seal body 51 having the groove 37, it exists in this gap. The static pressure of the liquid that rises increases outward in the radial direction of the upper surface 51 a of the second seal body 51.

In order to prevent the liquid from passing through the second through hole 55 a of the second casing structure 53, that is, to prevent the liquid from leaking to the outside of the second casing structure 53, the second seal body 51 is rotated by the second seal body 51. The static pressure of the liquid generated in the gap between the upper surface 51a of the two seal body 51 and the lower surface 55b of the second upper casing 55 is balanced with the static pressure of the liquid existing in the second seal chamber 53a. Larger than that.

The static pressure of the liquid flowing into the second seal chamber 53a from the first seal chamber 33a through the first through hole 35a is reduced by the first seal body 31 rotating in the first seal chamber 33a. That is, the static pressure of the liquid in the second seal chamber 53a is lower than the static pressure of the liquid in the first seal chamber 33a. In the shaft seal device 30 according to the present embodiment, the static pressure of the liquid flowing into the second seal chamber 53a is reduced by the rotating first seal body 31, and the static pressure reduced by the rotating second seal body 51 is further reduced. The liquid having pressure is prevented from leaking from the second casing structure 53. Therefore, the object of the present invention can be achieved by designing the first seal body 31 and the second seal body 51 into shapes and dimensions that satisfy such conditions. Since the rotational speeds of the first seal body 31 and the second seal body 51 depend on the operating conditions of the pump, the radius of the first seal body 31 and the radius of the second seal body 51 are suitable for the pump specifications and operating conditions. In addition, by forming surface shapes on the upper surface 31a and the upper surface 51a that allow the liquid to rotate with the rotation of the first seal body 31 and the second seal body 51, respectively, various pumps and use conditions can be obtained. It is possible to respond.

The upper surface 31a of the first seal body 31 causes centrifugal force to be applied to the liquid flowing in the gap between the upper surface 31a of the first seal body 31 and the lower surface 35b of the first upper casing 35 by the rotation of the first seal body 31. Configured as a surface that can be applied. Therefore, according to various pumps and operating conditions, the radius of the first seal body 31 and the gap between the upper surface 31a of the first seal body 31 and the lower surface 35b of the first upper casing 35 are set to suitable dimensions. In this case, the upper surface 31 a of the first seal body 31 may be a flat surface without the groove 37.

Similarly, the upper surface 51 a of the second seal body 51 is converted into a liquid that flows in the gap between the upper surface 51 a of the second seal body 51 and the lower surface 55 b of the second upper casing 55 by the rotation of the second seal body 51. Configured as a surface capable of applying centrifugal force. Therefore, when the radius of the second seal body 51 and the gap between the upper surface 51a of the second seal body 51 and the lower surface 55b of the second upper casing 55 are set to suitable dimensions, the second seal body The upper surface 51 a of 51 may be a flat surface without the groove 37. In one embodiment, the groove 37 may be formed only on either the upper surface 31 a of the first seal body 31 or the upper surface 51 a of the second seal body 51.

Furthermore, the diameter of the first seal body 31 and the diameter of the second seal body 51 can be designed according to the pump specifications and operating conditions. Therefore, in the embodiment shown in FIG. 2, the diameter of the second seal body 51 is the same as the diameter of the first seal body 31, but the diameter of the second seal body 51 is the same as the diameter of the first seal body 31. May be different. Similarly in the embodiments shown in FIGS. 7, 8, 9, 10, 11, and 12 described later, the diameter of the second seal body 51 is the same as the diameter of the first seal body 31. It may be different or different.

The shaft seal device 30 shown in FIG. 2 includes a seal casing 70 having two casing

structures

33 and 53 arranged along the axial direction of the rotating shaft 6, and the inside of each of the two

casing structures

33 and 53. Are provided with two

seal chambers

33a and 53a, and two

seal bodies

31 and 51 accommodated in the two

seal chambers

33a and 53a, respectively. However, the shaft seal device 30 includes a seal casing having three or more casing structures arranged along the axial direction of the

rotating shaft

6, and 3 formed inside each of the three or more casing structures. You may have three or more seal bodies accommodated in each of one or more seal chambers and three or more seal chambers. That is, the shaft seal device 30 includes a seal casing having a plurality of casing structures arranged along the axial direction of the rotating shaft, a plurality of seal chambers formed inside each of the plurality of casing structures, A plurality of seal bodies accommodated in each of the seal chambers. The plurality of seal structures and the plurality of seal bodies are arranged in series along the axial direction of the rotating shaft 6. The number of seal structures and the number of seal bodies can be set according to the pump specifications and operating conditions.

Similarly, in the embodiments shown in FIGS. 7, 8, 9, 10, 11, and 12 described later, the shaft seal device 30 has a plurality of casing structures arranged along the axial direction of the rotation shaft. A seal casing having a body, a plurality of seal chambers formed inside each of the plurality of casing structures, and a plurality of seal bodies accommodated in each of the plurality of seal chambers may be included.

As described above, in the shaft seal device 30 according to this embodiment, the liquid is axially arranged by the plurality of

seal bodies

31 and 51 that are arranged in series in the axial direction of the rotary shaft 6 and rotate integrally with the rotary shaft 6. Leaking from the sealing device 30 is prevented. Therefore, even when the pressure of the liquid flowing through the discharge elbow pipe 4 of the vertical shaft pump is high, the liquid can be prevented from leaking from the shaft seal device 30. Further, since the other components of the vertical shaft pump exist around the shaft seal device 30, even when the diameter of the

seal bodies

31, 51 cannot be increased, the liquid is sealed by the plurality of

seal bodies

31, 51. Leakage from 30 can be effectively prevented.

Furthermore, since the shaft seal device 30 according to the present embodiment is a non-contact shaft seal device in which the plurality of

seal bodies

31 and 51 are not in sliding contact with other members, the plurality of

seal bodies

31 and 51 are not worn. Therefore, the maintenance frequency of the shaft seal device 30 can be greatly reduced. Moreover, since each sealing

body

31 and 51 exhibits a sealing function in non-contact, only the heat | fever by a fluid shear force generate | occur | produces in the shaft seal device 30. FIG. Therefore, the amount of heat generated in the shaft seal device 30 is very small compared to a shaft seal device including components that are in sliding contact with each other, and a liquid such as cooling water or flushing liquid is supplied to the shaft seal device. There is no need to install additional facilities. Further, unlike the mechanical seal, it is not necessary to precisely finish the surface of the constituent members such as the rotating ring and the fixed ring, and accurate assembly is not required.

FIG. 4A is a top view showing another embodiment of the first seal body 31, and FIG. 4B is a cross-sectional view taken along the line BB of FIG. 4A. As shown in FIGS. 4A and 4B, the upper surface 31 a of the first seal body 31 has a plurality of grooves extending radially from the inner peripheral surface (that is, the through hole 31 b) of the seal body 31 to the outer peripheral surface of the seal body 31. 37 is formed. In the embodiment shown in FIG. 4A, 24 grooves 37 are formed, but the number of grooves 37 may be more or less than 24. The groove 37 extends radially, and the width of the groove 37 gradually increases toward the radially outer side of the first seal body 31. The first seal body 31 in which such a groove 37 is formed also exists in a gap between the lower surface 35 b of the first upper casing 35 and the upper surface 31 a of the first seal body 31 due to the rotation of the first seal body 31. A centrifugal force can be efficiently applied to the liquid, and a large centrifugal force field can be formed in the gap. Needless to say, since the upper surface 31 a of the first seal body 31 has the purpose of applying centrifugal force to the liquid flowing on the upper surface 31 a, the groove 37 is formed in the radial direction of the first seal body 31. May be inclined or may not extend linearly. Further, the width of the groove 37 may not gradually increase toward the outside in the radial direction. Note that the groove 37 shown in FIGS. 4A and 4B may be formed in the upper surface 51 a of the second seal body 51.

FIG. 5A is a top view showing still another embodiment of the first seal body 31, and FIG. 5B is a cross-sectional view taken along the line CC of FIG. 5A. The configuration that is not particularly described in the present embodiment is the same as the configuration of the first seal body 31 illustrated in FIGS. 3A and 3B, and thus redundant description thereof is omitted. Also in the present embodiment, a plurality of radially extending grooves 37 are formed on the upper surface 31a of the first seal body 31, and the inner end 37a of the groove 37 is the inner peripheral surface of the first seal body 31 (that is, the through hole). 31b) has not been reached. That is, the inner end 37 a of the groove 37 of this embodiment is located between the inner peripheral surface and the outer peripheral surface of the first seal body 31. The width of the groove 37 is constant from the inner end 37a to the outer end. The first seal body 31 in which such a groove 37 is formed also exists in a gap between the lower surface 35 b of the first upper casing 35 and the upper surface 31 a of the first seal body 31 due to the rotation of the first seal body 31. A centrifugal force can be efficiently applied to the liquid, and a large centrifugal force field can be formed in the gap. Needless to say, since the upper surface 31a of the first seal body 31 has the purpose of applying centrifugal force to the liquid flowing on the first upper surface 31a, the groove 37 is formed in the radial direction of the first seal body 31. May be inclined with respect to, or may not extend linearly. Furthermore, the width of the groove 37 may not be constant. Note that the groove 37 shown in FIGS. 5A and 5B may be formed in the upper surface 51 a of the second seal body 51.

6A is a top view showing still another embodiment of the first seal body 31, and FIG. 6B is a cross-sectional view taken along the line DD of FIG. 6A. The configuration that is not particularly described in the present embodiment is the same as the configuration of the first seal body 31 illustrated in FIGS. 4A and 4B, and thus redundant description thereof is omitted. Also in the present embodiment, a plurality of radially extending grooves 37 are formed on the upper surface 31a of the first seal body 31, and the inner end 37a of the groove 37 is the inner peripheral surface of the first seal body 31 (that is, the through hole). 31b) has not been reached. That is, the inner end 37 a of the groove 37 of this embodiment is located between the inner peripheral surface and the outer peripheral surface of the first seal body 31. The width of the groove 37 gradually increases toward the outer side in the radial direction of the first seal body 31. The first seal body 31 in which such a groove 37 is formed also exists in a gap between the lower surface 35 b of the first upper casing 35 and the upper surface 31 a of the first seal body 31 due to the rotation of the first seal body 31. A centrifugal force can be efficiently applied to the liquid, and a large centrifugal force field can be formed in the gap. Needless to say, since the upper surface 31 a of the first seal body 31 has the purpose of applying centrifugal force to the liquid flowing on the upper surface 31 a, the groove 37 is formed in the radial direction of the first seal body 31. May be inclined or may not extend linearly. Further, the width of the groove 37 may not gradually increase toward the outside in the radial direction. Note that the groove 37 shown in FIGS. 6A and 6B may be formed in the upper surface 51 a of the second seal body 51.

FIG. 7 is a cross-sectional view showing a shaft seal device 30 according to another embodiment. The configuration that is not particularly described in the present embodiment is the same as the configuration of the shaft seal device 30 illustrated in FIG. The first seal body 31 of the shaft seal device 30 shown in FIG. 7 has an upper surface (annular surface) 31 a that is inclined downward toward the radially outer side of the first seal body 31. Similarly, the second seal body 51 has an upper surface (annular surface) 51 a that is inclined downward toward the radially outer side of the second seal body 51. That is, the upper surface 31 a of the first seal body 31 and the upper surface 51 a of the second seal body 51 are inclined downward with respect to a plane perpendicular to the axis of the rotation shaft 6.

In the present embodiment, the upper surface 31a of the first seal body 31 and the upper surface 51a of the second seal body 51 are inclined linearly. More specifically, the upper surface 31 a of the first seal body 31 and the upper surface 51 a of the second seal body 51 are inclined linearly when viewed in a cross section parallel to the axis of the rotation shaft 6. A lower surface 35b of the first upper casing 35 that faces the upper surface 31a of the first seal body 31 via a gap extends along the upper surface 31a of the first seal body 31, and is spaced from the upper surface 51a of the second seal body 51. The lower surface 55 b of the second upper casing 55 that opposes the second upper casing 55 extends along the upper surface 51 a of the second seal body 51. More specifically, the lower surface 35b of the first upper casing 35 is parallel to the upper surface 31a of the first seal body 31 when viewed in a cross section parallel to the axis of the rotary shaft 6, and has the same inclination angle. Have. Accordingly, the size of the gap formed between the upper surface 31a of the first seal body 31 and the lower surface 35b of the first upper casing 35 (that is, the upper surface 31a of the first seal body 31 and the lower surface 35b of the first upper casing 35). The distance between them is constant. Similarly, the lower surface 55b of the second upper casing 55 is parallel to the upper surface 51a of the second seal body 51 when viewed in a cross section parallel to the axis of the rotary shaft 6, and has the same inclination angle. Therefore, the size of the gap formed between the upper surface 51a of the second seal body 51 and the lower surface 55b of the second upper casing 55 (that is, the upper surface 51a of the second seal body 51 and the lower surface 55b of the second upper casing 55). The distance between them is constant.

7, a plurality of grooves 37 are formed in the upper surface 31a of the first seal body 31 and the upper surface 51a of the second seal body 51, respectively. The grooves 37 of the first seal body 31 shown in FIG. 7 extend radially from the inner peripheral surface (that is, the through hole 31 b) of the first seal body 31 to the outer peripheral surface of the first seal body 31. Similarly, the groove 37 of the second seal body 51 shown in FIG. 7 extends radially from the inner peripheral surface of the second seal body 51 to the outer peripheral surface of the second seal body 51. As described with reference to FIGS. 3A and 3B, the width of the groove 37 of the first seal body 31 and the second seal body 51 may be constant from the inner end to the outer end, As described with reference to FIG. 4B, the

seal bodies

31 and 51 may gradually increase toward the outer side in the radial direction. Alternatively, as described with reference to FIG. 5A and FIG. 5B or FIG. 6A and FIG. 6B, the inner end 37a of the groove 37 is located between the inner peripheral surface and the outer peripheral surface of each

seal body

31, 51. It may be.

Also in the present embodiment, a necessary and sufficient centrifugal force field is generated in the gap between the upper surface 31a of the first seal body 31 and the lower surface 35b of the first upper casing 35 by the rotation of the first seal body 31. The rotational speed of the first seal body 31, the diameter of the first seal body 31, and the kinematic viscosity of the liquid are set. Similarly, the gap between the upper surface 51a of the second seal body 51 and the lower surface 55b of the second upper casing 55 is such that a necessary and sufficient centrifugal force field is generated in the gap by the rotation of the second seal body 51. The rotational speed of the two seal bodies 51, the diameter of the second seal body 51, and the kinematic viscosity of the liquid are set.

In the present embodiment, since the circumferential velocity component is generated in the liquid by the action of the groove 37 of the rotating first seal body 31, the liquid on the upper surface 31 a of the first seal body 31 and the liquid in the groove 37 are centrifuged. Force is generated. Furthermore, since the gap between the upper surface 31a of the first seal body 31 and the lower surface 35b of the first upper casing 35 is set to a suitable size, centrifugal force can be applied to the liquid present in the gap. . Similarly, since the circumferential velocity component is generated in the liquid by the action of the groove 37 of the rotating second seal body 51, the liquid on the upper surface 51a of the second seal body 51 and the liquid in the groove 37 have a centrifugal force. appear. Furthermore, since the gap between the upper surface 51a of the second seal body 51 and the lower surface 55b of the second upper casing 55 is set to a suitable size, centrifugal force can be applied to the liquid present in the gap. .

As described above, when the radius of the first seal body 31 and the gap between the upper surface 31a of the first seal body 31 and the lower surface 35b of the first upper casing 35 are set to suitable dimensions, The groove 37 may not be formed on the upper surface 31 a of the one seal body 31. Similarly, when the radius of the second seal body 51 and the gap between the upper surface 51a of the second seal body 51 and the lower surface 55b of the second upper casing 55 are set to suitable dimensions, the second seal The groove 37 may not be formed on the upper surface 51 a of the body 51. Alternatively, the groove 37 may be formed only on either the upper surface 31 a of the first seal body 31 or the upper surface 51 a of the second seal body 51.

In the shaft seal device 30 shown in FIG. 7, the second seal body 51 has the same configuration as the first seal body 31. Although not shown, either the upper surface 31 a of the first seal body 31 or the upper surface 51 a of the second seal body 51 shown in FIG. 7 may be configured as an annular surface perpendicular to the axis of the rotating shaft 6. (See FIG. 2).

FIG. 8 is a sectional view showing a modification of the shaft seal device 30 shown in FIG. The configuration that is not particularly described in the present embodiment is the same as the configuration of the shaft seal device 30 illustrated in FIG. The first seal body 31 of the shaft seal device 30 shown in FIG. 8 also has an upper surface (annular surface) 31a that is inclined downward toward the radially outer side of the first seal body 31, and this upper surface 31a is curved. is doing. More specifically, the upper surface 31 a of the first seal body 31 is inclined in a curved shape when viewed in a cross section parallel to the axis of the rotary shaft 6. In the shaft seal device shown in FIG. 8, the second seal body 51 has a configuration similar to that of the first seal body 31. That is, the second seal body 51 also has an upper surface (annular surface) 51 a that is inclined downward toward the radially outer side of the second seal body 51, and the upper surface 51 a is parallel to the axis of the rotating shaft 6. When viewed in cross section, it is inclined in a curved line.

The curvature of the upper surface 31a may be constant or may change gradually. When the curvature of the upper surface 31a is constant, the upper surface 31a extends in an arc shape. When the curvature of the upper surface 31a gradually changes, the curvature of the upper surface 31a may gradually increase from the inner peripheral surface of the first seal body 31 to the outer peripheral surface of the first seal body 31 or gradually decrease. May be. A lower surface 35 b of the first upper casing 35 that faces the upper surface 31 a of the first seal body 31 via a gap extends along the upper surface 31 a of the first seal body 31. That is, the size of the gap formed between the upper surface 31a of the first seal body 31 and the lower surface 35b of the first upper casing 35 (that is, the upper surface 31a of the first seal body 31 and the lower surface 35b of the first upper casing 35). The lower surface 35b of the first upper casing 35 is formed so that the distance between the first upper casing 35 and the second casing 35 is constant.

Similarly, the curvature of the upper surface 51a may be constant or may gradually change. When the curvature of the upper surface 51a is constant, the upper surface 51a extends in an arc shape. When the curvature of the upper surface 51a gradually changes, the curvature of the upper surface 51a may gradually increase from the inner peripheral surface of the second seal body 51 to the outer peripheral surface of the second seal body 51, or gradually decrease. May be. A lower surface 55b of the second upper casing 55 facing the upper surface 51a of the second seal body 51 with a gap extends along the upper surface 51a of the second seal body 51. That is, the size of the gap formed between the upper surface 51a of the second seal body 51 and the lower surface 55b of the second upper casing 55 (that is, the upper surface 51a of the second seal body 51 and the lower surface 55b of the second upper casing 55). The lower surface 55b of the second upper casing 55 is formed so that the distance between the upper casing 55 and the second casing 55 is constant.

In the shaft seal device 30 shown in FIG. 8, the second seal body 51 has the same configuration as the first seal body 31. Although not shown, either the upper surface 31 a of the first seal body 31 or the upper surface 51 a of the second seal body 51 shown in FIG. 8 may be configured as an annular surface perpendicular to the axis of the rotating shaft 6. However, it may be inclined linearly downward (see FIG. 7) outward in the radial direction.

The shaft seal device 30 shown in FIG. 7 or 8 is also arranged in series in the axial direction of the rotary shaft 6, and the liquid is sealed by the plurality of

seal bodies

31, 51 that rotate integrally with the rotary shaft 6. Prevent leakage from 30. Therefore, even when the pressure of the liquid flowing through the discharge elbow pipe 4 of the vertical shaft pump is high, the liquid can be prevented from leaking from the shaft seal device 30. Further, since the other components of the vertical shaft pump exist around the shaft seal device 30, even when the diameter of the

seal bodies

31, 51 cannot be increased, the liquid is sealed by the plurality of

seal bodies

31, 51. Leakage from 30 can be effectively prevented.

seal bodies

31 and 51 are not in sliding contact with other members, the plurality of

seal bodies

body

FIG. 9 is a cross-sectional view showing a shaft seal device 30 according to still another embodiment. The configuration that is not particularly described in the present embodiment is the same as the configuration of the shaft seal device 30 illustrated in FIG. A shaft seal device 30 shown in FIG. 9 is a non-contact type upper seal structure 45 that seals a gap between the rotary shaft 6 and the second through hole 55a provided above the second seal body 51. Is further provided.

As shown in FIG. 9, the second upper casing 55 has an extension portion 55 c that extends upward along the longitudinal direction of the rotating shaft 6. The extension part 55 c has a cylindrical shape and surrounds the rotation shaft 6. The 2nd through-hole 55a which the rotating shaft 6 penetrates is formed of the whole internal peripheral surface of the 2nd upper casing 55 containing the extension part 55c. A sleeve 47 is fixed to the outer peripheral surface of the rotating shaft 6, and the sleeve 47 extends in the vertical direction through the second through hole 55 a of the second upper casing 55. A gap is formed between the outer peripheral surface of the sleeve 47 and the second through hole 55a.

The non-contact type upper seal structure 45 of the present embodiment is a labyrinth seal constituted by an extension portion 55c of the second upper casing 55 and a sleeve 47. The non-contact type upper seal structure 45 may be a flat seal that does not have a labyrinth structure.

The labyrinth structure of the labyrinth seal is, for example, a plurality of parallel grooves (not shown) formed in the second through hole 55a. The plurality of parallel grooves constituting the labyrinth structure may be formed on the outer peripheral surface of the sleeve 47, or may be formed on both the second through hole 55a and the outer peripheral surface of the sleeve 47. The plurality of parallel grooves are parallel to each other, and each parallel groove extends in a plane perpendicular to the axis of the rotation shaft 6 on the outer peripheral surface of the second through hole 55 a and / or the sleeve 47. The spacing between adjacent parallel grooves may be equal or different. Furthermore, the cross-sectional shape of the top of the parallel groove is arbitrary. For example, the tops of the parallel grooves may have a triangular cross-sectional shape, a quadrangular cross-sectional shape, or a trapezoidal cross-sectional shape. Alternatively, the top of the parallel groove may have a rounded cross-sectional shape (for example, a hemispherical cross-sectional shape).

The groove constituting the labyrinth structure may be a thread groove extending spirally on the outer peripheral surface of the second through hole 55a and / or the sleeve 47. The rotational direction of the spirally extending thread groove is preferably a direction that exerts a pumping action to push the liquid back to the second seal chamber 53a when the rotating shaft 6 is rotated. That is, it is preferable that the thread groove extends spirally in the direction opposite to the rotation direction of the rotation shaft 6. The pitch of the thread groove and the number of threads are arbitrary. For example, one screw groove may be formed on the outer peripheral surface of the second through hole 55a and / or the sleeve 47 at an unequal pitch, and multiple threads are formed in the second through hole 55a and / or the sleeve 47. You may form on the outer peripheral surface. The shape of the top of the thread groove is arbitrary. For example, the top of the thread groove may have a triangular cross-sectional shape, a square cross-sectional shape, or a trapezoidal cross-sectional shape. Alternatively, the top of the thread groove may have a rounded cross-sectional shape (for example, a hemispherical cross-sectional shape).

Furthermore, the shaft seal device 30 has a liquid leakage cover 48 surrounding the upper seal structure 45. The leak cover 48 is fixed to the upper surface of the second upper casing 55. That is, it is fixed to the upper part of the seal casing 70. The side wall of the liquid leakage cover 48 is provided with an opening 48b that allows the internal space 48a of the liquid leakage cover 48 to communicate with the outside, and the internal space 48a communicates with the outside of the liquid leakage cover 48 through the opening 48b. Further, a leakage pipe 49 is connected to the opening 48b. The leakage pipe 49 extends into the suction water tank 5 (see FIG. 1), and the tip of the leakage pipe 49 is located above the liquid level in the suction water tank 5. In one embodiment, the tip of the leak pipe 49 may be located above a gutter (not shown) formed in the pump installation floor 22 (see FIG. 1). The liquid that has flowed from the leak pipe 49 into the side groove may be returned to the suction water tank 5 through the side groove, or may be collected in a collection container such as a tank (not shown). The liquid leakage cover 48 may be provided with a plurality of openings 48b. In this case, a leak pipe 49 is connected to each opening 48b.

The pressure of the liquid existing in the second seal chamber 53 a of the second casing structure 53 is caused between the lower surface 55 b of the second upper casing 55 and the upper surface 51 a of the second seal body 51 by the rotation of the second seal body 51. When the centrifugal force applied to the liquid existing in the gap is higher, the liquid reaches the upper seal structure 45. In this case, the liquid is decompressed when passing through the upper seal structure 45 and flows into the internal space 48 a of the leak cover 48.

The inner space 48a of the leak cover 48 is connected to the leak pipe 49 through the opening 48b, and the tip of the leak pipe 49 communicates with the atmosphere in the suction water tank 5, and therefore leaked into the inner space 48a. The liquid is returned to the suction water tank 5. Therefore, the liquid is prevented from leaking from the leak cover 48. When the tip of the leak pipe 49 is located above a side groove (not shown) formed in the pump installation floor 22 (see FIG. 1), the tip of the leak pipe 49 is exposed to the atmosphere above the side groove. Because of the communication, the liquid leaking into the internal space 48a is returned to the suction water tank 5 through the side groove or is collected in the collection tank.

As shown in FIG. 9, the drain plate 50 may be fixed to the rotary shaft 6 in the internal space 48 a of the leak cover 48. The drain plate 50 is disposed above the upper seal structure 45. When the liquid that has passed through the upper seal structure 45 collides with the draining plate 50, the moving direction of the liquid can be changed to the side or downward.

The upper seal structure 45 is a non-contact type seal in which the sleeve 47 that rotates integrally with the rotary shaft 6 does not contact the second upper casing 55. Therefore, the sleeve 47 and the second upper casing 55 are not worn, and the maintenance frequency of the upper seal structure 45 can be greatly reduced. Further, since the upper seal structure 45 exhibits a sealing function without contact, frictional heat is not generated, and it is not necessary to supply liquid such as cooling water and flushing liquid to the upper seal structure 45.

In the upper seal structure 45, the static pressure of the liquid generated in the gap between the upper surface 51a of the second seal body 51 and the lower surface 55b of the second upper casing 55 by the rotating second seal body 51 is increased in the second seal chamber. Even when it is smaller than the static pressure of the liquid existing in 53 a, it functions as an auxiliary seal that prevents the liquid from leaking outside the shaft seal device 30. In one embodiment, the amount of liquid passing through the upper seal structure 45 may be adjusted by appropriately designing the shape and size of the second seal body 51 and / or the shape of the upper seal structure 45. .

When the shaft seal device 30 has three or more casing structures and three or more seal bodies accommodated in seal chambers formed in the casing structures, the upper seal structure 45 is , And disposed above the uppermost seal body. More specifically, the upper seal structure 45 is composed of an extension provided in the upper casing of the uppermost casing structure and a sleeve fixed to the rotary shaft 6 and is located on the uppermost side. A gap between the through hole of the casing structure and the rotary shaft 6 is sealed.

FIG. 10 is a cross-sectional view showing a shaft seal device 30 according to still another embodiment. The configuration that is not particularly described in the present embodiment is the same as the configuration of the shaft seal device 30 illustrated in FIG. A first casing structure 33 of the shaft seal device 30 shown in FIG. 10 includes a lower casing 34 as well as the first upper casing 35 and the first intermediate casing 36 described above.

The lower casing 34 has a lower through hole 34 a through which the rotary shaft 6 passes, and the center line of the lower through hole 34 a coincides with the axis of the rotary shaft 6. The first intermediate casing 36 has a cylindrical inner peripheral surface 36a. The first intermediate casing 36 is fixed to the lower casing 34 and the first upper casing 35 while being sandwiched between the lower casing 34 and the first upper casing 35. Thereby, a first seal chamber 33 a in which the first seal body 31 is accommodated is formed in the first casing structure 33.

In the present embodiment, the first seal chamber 33a is formed by the lower surface 35b of the first upper casing 35, the inner peripheral surface 36a of the first intermediate casing 36, and the upper surface 34b of the lower casing 34. The first seal body 31 is fixed to the rotary shaft 6 inside the first seal chamber 33a. The lower surface 35 b of the first upper casing 35 and the upper surface 34 b of the lower casing 34 are planes perpendicular to the rotation shaft 6, and the inner peripheral surface 36 a of the first intermediate casing 36 is concentric with the outer peripheral surface of the rotation shaft 6. is there. The first seal chamber 33a communicates with the lower through hole 34a and the first through hole 35a, and the first seal chamber 33a is located between the lower through hole 34a and the first through hole 35a. The rotating shaft 6 extends in the vertical direction through the lower through hole 34a, the first seal chamber 33a, and the first through hole 35a.

In the present embodiment, the lower casing 34 has a lower extension 34 c that extends downward along the longitudinal direction of the rotating shaft 6. The lower extension 34 c has a cylindrical shape and surrounds the rotation shaft 6. The lower through hole 34a through which the rotary shaft 6 passes is formed by the entire inner peripheral surface of the lower casing 34 including the extension 34c.

As shown in FIG. 10, the shaft seal device 30 is fixed on the shaft seal device mounting surface 4a of the discharge elbow pipe 4 so as to close the through hole 4b formed in the discharge elbow pipe 4. In the present embodiment, the lower surface of the lower casing 34 is connected to the shaft seal device mounting surface 4a.

Furthermore, a sleeve 41 is fixed to the outer peripheral surface of the rotary shaft 6, and the sleeve 41 extends in the vertical direction through the lower through hole 34 a of the lower casing 34. A gap is formed between the outer peripheral surface of the sleeve 41 and the lower through hole 34a.

In the present embodiment, the lower seal structure 40 is configured by the lower extension 34 c of the lower casing 34 and the sleeve 41. The lower seal structure 40 may be a labyrinth seal having a labyrinth structure or a flat seal not having a labyrinth structure.

The labyrinth structure of the labyrinth seal is, for example, a plurality of parallel grooves (not shown) formed in the lower through hole 34a. The plurality of parallel grooves constituting the labyrinth structure may be formed on the outer peripheral surface of the sleeve 41, or may be formed on both the lower through hole 34 a and the outer peripheral surface of the sleeve 41. The plurality of parallel grooves are parallel to each other, and each parallel groove extends in a plane perpendicular to the axis of the rotation shaft 6 on the outer peripheral surface of the lower through hole 34 a and / or the sleeve 41. The spacing between adjacent parallel grooves may be equal or different. Furthermore, the cross-sectional shape of the top of the parallel groove is arbitrary. For example, the tops of the parallel grooves may have a triangular cross-sectional shape, a quadrangular cross-sectional shape, or a trapezoidal cross-sectional shape. Alternatively, the top of the parallel groove may have a rounded cross-sectional shape (for example, a hemispherical cross-sectional shape).

The groove constituting the labyrinth structure may be a screw groove that extends spirally on the outer peripheral surface of the lower through hole 34a and / or the sleeve 41. The direction of rotation of the spirally extending thread groove is preferably a direction that exerts a pumping action that pushes the liquid back to the through-hole 4b formed in the discharge elbow pipe 4 when the rotating shaft 6 is rotated. That is, it is preferable that the thread groove extends spirally in the direction opposite to the rotation direction of the rotation shaft 6. The pitch of the thread groove and the number of threads are arbitrary. For example, one screw groove may be formed at an unequal pitch on the outer peripheral surface of the lower through hole 34a and / or the sleeve 41, and multiple thread grooves may be formed at the lower through hole 34a and / or the sleeve 41. You may form on the outer peripheral surface. The shape of the top of the thread groove is arbitrary. For example, the top of the thread groove may have a triangular cross-sectional shape, a square cross-sectional shape, or a trapezoidal cross-sectional shape. Alternatively, the top of the thread groove may have a rounded cross-sectional shape (for example, a hemispherical cross-sectional shape).

In the present embodiment, the side wall of the first casing structure 33, more specifically, the first intermediate casing 36 has an opening 33b communicating with the first seal chamber 33a. The opening 33b extends from the first seal chamber 33a to the outer surface of the first casing structure 33 (that is, the outer surface of the first intermediate casing 36). The opening 33 b shown in FIG. 10 extends in the radial direction of the rotating shaft 6. In one embodiment, the opening 33 b may extend upward or downward with respect to the radial direction of the rotating shaft 6. Alternatively, the opening 33 b may extend obliquely with respect to the radial direction of the rotating shaft 6. Through the opening 33b, the first seal chamber 33a communicates with the outside of the first casing structure 33. A first drain pipe 43 is connected to the opening 33b. The first drain pipe 43 extends into the suction water tank 5 (see FIG. 1), and the tip of the first drain pipe 43 is located above the liquid level in the suction water tank 5.

In one embodiment, the tip of the first drain pipe 43 may be located above a side groove (not shown) formed in the pump installation floor 22 (see FIG. 1). The liquid that has flowed from the first drain pipe 43 into the side groove may be returned to the suction water tank 5 through the side groove, or may be collected in a collection container such as a tank (not shown).

A plurality of openings 33b may be provided. In this case, the interval between the adjacent openings 33b is arbitrary. For example, two openings 33b separated by 180 ° in the circumferential direction of the inner peripheral surface 36a of the first casing structure 33 may be provided on the side wall of the first casing structure 33, or the inner periphery of the first casing structure 33 may be provided. Four openings 33b that are 90 ° apart from each other in the circumferential direction of the surface 36a may be provided on the side wall of the first casing structure 33. When a plurality of openings 33b are provided, the first drain tube 43 is connected to each opening 33b.

A part of the liquid flowing through the discharge elbow pipe 4 (see FIG. 1) toward the discharge pipe 20 flows into the lower seal structure 40 through the through hole 4b. Further, the liquid passes through the lower seal structure 40 and flows into the first seal chamber 33a. The liquid is depressurized as it passes through the lower seal structure 40. The liquid that has passed through the lower seal structure 40 and reached the first seal chamber 33a flows into the first drain pipe 43 through the opening 33b provided in the side wall of the first casing structure 33, and the suction water tank 5 Returned to Since the liquid reaching the first seal chamber 33a is returned to the suction water tank 5 through the first drain pipe 43 communicating with the atmosphere, the pressure of the liquid in the first seal chamber 33a of the first casing structure 33 is lowered. To do. Therefore, the pressure of the liquid which should generate | occur | produce the 1st seal body 31 becomes lower than embodiment shown in FIG. Further, since the pressure of the liquid flowing into the second seal chamber 53a of the second casing structure 53 is also reduced, the liquid that should be generated by the second seal body 51 to prevent liquid leakage from the shaft seal device 30. Is lower than that of the embodiment shown in FIG. As a result, the shaft seal device 30 of the present embodiment can prevent leakage of higher pressure liquid as compared with the shaft seal device 30 shown in FIG. Further, when the shaft seal device 30 of the present embodiment is compared with the shaft seal device 30 shown in FIG. 2, the diameters of the first seal body 31 and the second seal body 51 can be reduced. The size of 30 (in particular, the size of the shaft seal device 30 in the direction perpendicular to the axis of the rotating shaft 6) can be reduced.

In the present embodiment, the pressure of the liquid in the first seal chamber 33a can be adjusted by changing the number of the openings 33b and / or the size of the diameter of the openings 33b. Therefore, by appropriately designing the number of openings 33b and / or the size of the diameter of the openings 33b, the first through holes 35a of the first casing structure 33 are passed through the second casing structures 53. The pressure of the liquid flowing into the two-seal chamber 53a can be adjusted.

In the present embodiment, the rotating first seal body 31 also generates a circumferential velocity component in the liquid present below the first seal body 31 in the first seal chamber 33a. Accordingly, centrifugal force also acts on the liquid existing below the first seal body 31 in the first seal chamber 33a, and the static pressure of the liquid in the first seal chamber 33a increases. When the difference between the static pressure of the liquid generated in the gap between the upper surface 31a of the first seal body 31 and the lower surface 35b of the first upper casing 35 and the static pressure of the liquid existing in the first seal chamber 33a is reduced. The amount of liquid flowing into the second seal chamber 53a of the second casing structure 53 increases. Therefore, the volume of the liquid existing below the first seal body 31 is made sufficiently larger than the volume of the gap between the upper surface 31a of the first seal body 31 and the lower surface 35b of the first upper casing 35. Is preferred. For example, the volume of the liquid existing below the first seal body 31 can be increased by increasing the distance between the lower surface of the first seal body 31 and the upper surface 34 b of the lower casing 34.

The lower seal structure 40 is a non-contact type seal in which the sleeve 41 that rotates integrally with the rotary shaft 6 does not contact the lower casing 34. Therefore, the sleeve 41 and the lower casing 34 are not worn, and the maintenance frequency of the lower seal structure 40 can be greatly reduced. Furthermore, since the lower seal structure 40 exhibits a sealing function without contact, frictional heat is not generated, and it is not necessary to supply liquids such as cooling water and flushing liquid to the lower seal structure 40.

As shown in FIG. 10, an opening 53 b communicating with the second seal chamber 53 a may be formed in the side wall of the second casing structure 53, more specifically, in the second intermediate casing 56. The opening 53b extends from the second seal chamber 53a to the outer surface of the second casing structure 53 (that is, the outer surface of the second intermediate casing 56). The opening 53 b shown in FIG. 10 extends in the radial direction of the rotating shaft 6. In one embodiment, the opening 53 b may extend upward or downward with respect to the radial direction of the rotation shaft 6. Alternatively, the opening 53 b may extend obliquely with respect to the radial direction of the rotation shaft 6. Through the opening 53b, the second seal chamber 53a communicates with the outside of the second casing structure 53. A second drain pipe 54 is connected to the opening 53b. The second drain pipe 54 extends into the suction water tank 5 (see FIG. 1), and the tip of the second drain pipe 54 is located above the liquid level in the suction water tank 5.

In one embodiment, the tip of the second drain pipe 54 may be located above a gutter (not shown) formed in the pump installation floor 22 (see FIG. 1). The liquid that has flowed from the second drain pipe 54 into the side groove may be returned to the suction water tank 5 through the side groove, or may be collected in a collection container such as a tank (not shown).

A plurality of openings 53b may be provided. Similar to the opening 33b described above, the interval between the adjacent openings 53b is arbitrary. When a plurality of openings 53b are provided, the second drain pipe 54 is connected to each opening 53b.

The liquid that has passed through the first through hole 35a from the first seal chamber 33a and reached the second seal chamber 53a flows into the second drain pipe 54 through the opening 53b provided in the side wall of the second casing structure 53. And returned to the suction water tank 5. Since the liquid reaching the second seal chamber 53a is returned to the suction water tank 5 through the second drain pipe 54 communicating with the atmosphere, the pressure of the liquid in the second seal chamber 53a of the second casing structure 53 decreases. To do. When the shaft seal device 30 has not only the opening 33b provided on the side wall of the first casing structure 33 but also the opening 53b provided on the side wall of the second casing structure 53, the liquid from the shaft seal device 30 In order to prevent leakage, the pressure of the liquid that should be generated by the first seal body 31 and the second seal body 51 can be further reduced. As a result, the shaft seal device 30 of this embodiment can effectively prevent leakage of high-pressure liquid. Furthermore, since the diameters of the first seal body 31 and the second seal body 51 can be further reduced, the size of the shaft seal device 30 (particularly, the shaft seal device in the direction perpendicular to the axis of the rotary shaft 6). 30 size) can be reduced.

Although not shown, the opening 33b provided on the side wall of the first casing structure 33 and the first drain pipe 43 connected to the opening 33b may be omitted. In this case, the shaft seal device 30 has only the opening 53b provided on the side wall of the second casing structure 53 and the second drain pipe 54 connected to the opening 53b.

Furthermore, by appropriately designing the shape / dimension of the first seal body 31, the shape / dimension of the second seal body 51, and the shape of the lower seal structure body 40, the first seal body 31 is provided on the side wall of the first casing structure 33. The opening 33b and the opening 53b provided on the side wall of the second casing structure 53 may be omitted. In this case, the first drain pipe 43 connected to the opening 33 b provided on the side wall of the first casing structure 33 and the second drain pipe connected to the opening 53 b provided on the side wall of the second casing structure 53. 54 is also omitted.

When the shaft seal device 30 has three or more casing structures and three or more seal bodies accommodated in seal chambers formed in the casing structures, the lower seal structure 40 is used. Is disposed below the lowermost seal body. More specifically, the lower seal structure 40 includes a lower extension provided in the lower casing of the lowermost casing structure, and a sleeve fixed to the rotary shaft 6. The gap between the through hole of the casing structure located on the lowermost side and the rotating shaft 6 is sealed.

Furthermore, when the seal casing 70 of the shaft seal device 30 has three or more casing structures (that is, three or more seal chambers), at least one seal chamber communicates with the outside of the seal chamber. One opening may be provided. That is, the seal casing 70 only needs to have at least one opening that communicates at least one seal chamber of the plurality of seal chambers with the outside of the seal casing 70. Also in this case, a drain pipe is connected to the opening. Alternatively, the seal casing 70 may not have the at least one opening by appropriately designing the shapes and dimensions of the plurality of seal bodies and the shape of the lower seal structure 40.

FIG. 11 is a cross-sectional view showing a shaft seal device 30 according to still another embodiment. The configuration that is not particularly described in the present embodiment is the same as the configuration of the shaft seal device 30 illustrated in FIG. In the shaft seal device 30 shown in FIG. 11, the upper seal structure 45 described with reference to FIG. 9 is attached to the shaft seal device 30 shown in FIG. 10. Therefore, the configuration of the upper seal structure 45 of the present embodiment is the same as the configuration of the upper seal structure 45 shown in FIG. 9, and thus detailed description of the upper seal structure 45 is omitted. In the following description, the extension 55c of the second upper casing 53 is referred to as the upper extension 55c.

As shown in FIG. 11, the first casing structure 33 of the shaft seal device 30 of the present embodiment is also sandwiched between the first upper casing 35, the lower casing 34, and the first upper casing 35 and the lower casing 35. A first intermediate casing 36 is provided. The first seal body 31 rotates inside a first seal chamber 33a formed by a lower surface 35b of the first upper casing 35, an inner peripheral surface 36a of the first intermediate casing 36, and an upper surface 34b of the lower casing 34. It is fixed to the shaft 6.

The lower casing 34 of the first casing structure 33 has a lower extension 34 c that extends downward along the longitudinal direction of the rotating shaft 6, and the lower through-hole 34 a through which the rotating shaft 6 passes is a lower extension. It is formed by the entire inner peripheral surface of the lower casing 34 including the portion 34c. A sleeve 41 is fixed to the outer peripheral surface of the rotary shaft 6, and the sleeve 41 extends in the vertical direction through the lower through hole 34 a of the lower casing 34. A gap is formed between the outer peripheral surface of the sleeve 41 and the lower through hole 34a. As described above, the non-contact type lower seal structure 40 of the present embodiment is a labyrinth seal or a flat seal constituted by the lower extension 34 c of the lower casing 34 and the sleeve 41. The rotating shaft 6 extends in the vertical direction through the lower through hole 34a, the first seal chamber 33a, and the first through hole 35a.

The second upper casing 55 of the second casing structure 53 has an upper extension 55c that extends upward along the longitudinal direction of the rotary shaft 6, and the second through hole 55a through which the rotary shaft 6 passes is an upper extension. It is formed by the entire inner peripheral surface of the second upper casing 55 including 55c. A sleeve 47 is fixed to the outer peripheral surface of the rotating shaft 6, and the sleeve 47 extends in the vertical direction through the second through hole 55 a of the second upper casing 55. A gap is formed between the outer peripheral surface of the sleeve 47 and the second through hole 55a. As described above, the non-contact type upper seal structure 45 of the present embodiment is a labyrinth seal or a flat seal configured by the upper extension 55 c of the second upper casing 55 and the sleeve 47.

According to the present embodiment, the liquid that has passed through the lower seal structure 40 and has flowed into the first seal chamber 33a is decompressed when passing through the lower seal structure 40. Furthermore, a part of the liquid that has passed through the lower seal structure 40 and reached the first seal chamber 33a flows into the drain pipe 43 through the opening 33b provided in the side wall of the first casing structure 33, It is returned to the suction tank 5. Since a part of the liquid reaching the first seal chamber 33a is returned to the suction water tank 5 through the drain pipe 43 communicating with the atmosphere, the pressure of the liquid in the first seal chamber 33a of the first casing structure 33 decreases. To do. Therefore, the pressure of the liquid that should be generated by the first seal body 31 and the second seal body 51 in order to prevent leakage of the liquid from the shaft seal device 30 can be reduced.

In one embodiment, the side wall of the second casing structure 53 may be provided with an opening 53b (see FIG. 10) communicating with the second seal chamber 53a. In this case, since the pressure of the liquid in the second seal chamber 53a can be further reduced, the first seal body 31 and the second seal body 51 are generated in order to prevent leakage of the liquid from the shaft seal device 30. The pressure of the liquid to be reduced can be further reduced.

As described above, by appropriately designing the shape / dimension of the first seal body 31, the shape / dimension of the second seal body 51, and the shape of the lower seal structure 40, the side wall of the first casing structure 33 is obtained. The opening 33b provided on the side wall and the opening 53b provided on the side wall of the second casing structure 53 may be omitted.

Furthermore, the pressure of the liquid existing in the second seal chamber 53 a of the second casing structure 53 is caused by the rotation of the second seal body 51 between the lower surface 55 b of the second upper casing 55 and the upper surface 51 a of the second seal body 51. Even if it is higher than the centrifugal force applied to the liquid existing in the gap, the liquid is further depressurized when passing through the upper seal structure 45 and flows into the internal space 48 a of the leak cover 48. However, the liquid that has flowed into the internal space 48 a of the leak cover 48 is returned to the suction water tank 5 via the leak pipe 49. Therefore, the shaft seal device 30 can reliably prevent the liquid from leaking from the shaft seal device 30. In one embodiment, by appropriately designing the shape and dimensions of the first seal body 31, the shape and dimensions of the second seal body 51, the shape of the upper seal structure 45, and the shape of the lower seal structure 40, The liquid can be prevented from passing through the second through hole 55a of the second casing structure 53. Alternatively, by appropriately designing the shape and dimensions of the seal body 31, the shape and dimensions of the second seal body 51, the shape of the upper seal structure 45, and the shape of the lower seal structure 40, the upper seal structure 45 You may adjust the quantity of the liquid which passes.

When the shaft seal device 30 has three or more casing structures and three or more seal bodies accommodated in seal chambers formed in the casing structures, the upper seal structure 45 is , And disposed above the uppermost seal body. More specifically, the upper seal structure 45 is composed of an upper extension provided in the upper casing of the uppermost casing structure and a sleeve fixed to the rotary shaft 6, and is located at the uppermost position. The gap between the through hole of the casing structure and the rotating shaft 6 is sealed. Further, the lower seal structure 40 is disposed below the lowermost seal body. More specifically, the lower seal structure 40 includes a lower extension provided in the lower casing of the lowermost casing structure, and a sleeve fixed to the rotary shaft 6. The clearance gap between the through-hole of the casing structure located in the lowest side and a rotating shaft is sealed.

The shaft seal device 30 according to the present embodiment is also arranged in series in the axial direction of the rotary shaft 6, and liquid leaks from the shaft seal device 30 by the plurality of

seal bodies

31 and 51 that rotate integrally with the rotary shaft 6. To prevent. Therefore, even when the pressure of the liquid flowing through the discharge elbow pipe 4 of the vertical shaft pump is high, the liquid can be prevented from leaking from the shaft seal device 30. Further, since the other components of the vertical shaft pump exist around the shaft seal device 30, even when the diameter of the

seal bodies

31, 51 cannot be increased, the liquid is sealed by the plurality of

seal bodies

31, 51. Leakage from 30 can be effectively prevented.

seal bodies

31 and 51 are not in sliding contact with other members, the plurality of

seal bodies

body

Furthermore, the upper seal structure 45 is a non-contact type seal in which the sleeve 47 that rotates integrally with the rotary shaft 6 does not contact the upper casing 35. Similarly, the lower seal structure 40 is a non-contact type seal in which the sleeve 41 that rotates integrally with the rotary shaft 6 does not contact the lower casing 34. Therefore, the maintenance frequency of the upper seal structure 45 and the lower seal structure 40 can be greatly reduced. Furthermore, since the upper seal structure 45 and the lower seal structure 40 exhibit a sealing function in a non-contact manner, frictional heat due to contact does not occur, and liquids such as cooling water and flushing liquid can be supplied to the upper seal structure 45 and There is no need to supply the lower seal structure 40.

FIG. 12 is a cross-sectional view showing a shaft seal device 30 according to still another embodiment. The configuration that is not particularly described in the present embodiment is the same as the configuration of the shaft seal device 30 illustrated in FIG. The shaft seal device 30 shown in FIG. 12 includes a non-contact type intermediate seal structure 60 that seals a gap between the rotary shaft 6 and the first through hole 35a.

Further, the shaft seal device 30 shown in FIG. 12 includes the liquid leakage cover 48 described with reference to FIG. 9, and an inner space 48 a of the liquid leakage cover 48 is provided on the side wall of the liquid leakage cover 48. There is provided at least one opening 48b communicating with the. The above-described leakage pipe 49 is connected to the opening 48b. As shown in FIG. 12, the above-described draining plate 50 may be fixed to the rotating shaft 6 in the internal space 48 a of the leak cover 48.

Furthermore, at least one opening 53b described with reference to FIG. 10 is provided on the side wall of the second casing structure 53 of the shaft seal device 30, and the second drain described above is provided in the opening 53b. A tube 54 is connected.

In the shaft seal device 30 shown in FIG. 12, a sleeve 61 is fixed to the outer peripheral surface of the rotating shaft 6, and the sleeve 61 is formed in the first through-hole formed in the first upper casing 35 of the first casing structure 33. It extends in the vertical direction through the hole 35a. A gap is formed between the sleeve 61 and the first through hole 35a. The first seal chamber 33a of the first casing structure 33 communicates with the second seal chamber 53a of the second casing structure 53 through a gap formed between the sleeve 61 and the first through hole 35a.

The non-contact type intermediate seal structure 60 of the present embodiment is a labyrinth seal constituted by a first through hole 35a formed in the first upper casing 35 and a sleeve 61. The non-contact type intermediate seal structure 60 may be a flat seal that does not have a labyrinth structure.

The labyrinth structure of the labyrinth seal is, for example, a plurality of parallel grooves (not shown) formed in the first through hole 35a. The plurality of parallel grooves constituting the labyrinth structure may be formed on the outer peripheral surface of the sleeve 61, or may be formed on both the first through hole 35 a and the outer peripheral surface of the sleeve 61. The plurality of parallel grooves are parallel to each other, and each parallel groove extends in a plane perpendicular to the axis of the rotation shaft 6 on the outer peripheral surface of the first through hole 35 a and / or the sleeve 61. The spacing between adjacent parallel grooves may be equal or different. Furthermore, the cross-sectional shape of the top of the parallel groove is arbitrary. For example, the tops of the parallel grooves may have a triangular cross-sectional shape, a quadrangular cross-sectional shape, or a trapezoidal cross-sectional shape. Alternatively, the top of the parallel groove may have a rounded cross-sectional shape (for example, a hemispherical cross-sectional shape).

The groove constituting the labyrinth structure may be a thread groove extending spirally on the outer peripheral surface of the first through hole 35a and / or the sleeve 61. The rotational direction of the spirally extending thread groove is preferably a direction that exerts a pumping action that pushes the liquid back to the first seal chamber 33a when the rotating shaft 6 is rotated. That is, it is preferable that the thread groove extends spirally in the direction opposite to the rotation direction of the rotation shaft 6. The pitch of the thread groove and the number of threads are arbitrary. For example, one screw groove may be formed on the outer peripheral surface of the first through hole 35a and / or the sleeve 61 at an unequal pitch, and multiple thread grooves may be formed in the first through hole 35a and / or the sleeve 61. You may form on the outer peripheral surface. The shape of the top of the thread groove is arbitrary. For example, the top of the thread groove may have a triangular cross-sectional shape, a square cross-sectional shape, or a trapezoidal cross-sectional shape. Alternatively, the top of the thread groove may have a rounded cross-sectional shape (for example, a hemispherical cross-sectional shape).

Part of the liquid flowing through the discharge elbow pipe 4 (see FIG. 1) toward the discharge pipe 20 flows into the first seal chamber 33a through the through hole 4b. The static pressure of the liquid flowing into the second seal chamber 53a from the first seal chamber 33a through the first through hole 35a is reduced by the first seal body 31 rotating in the first seal chamber 33a, and further, the intermediate seal Reduced when passing through the structure 60. Further, the liquid that has reached the second seal chamber 53 a flows into the second drain pipe 54 through the opening 53 b provided on the side wall of the second casing structure 53, and is returned to the suction water tank 5. Accordingly, the pressure of the liquid in the second seal chamber 53a of the second casing structure 53 further decreases. Therefore, the pressure of the liquid that should be generated by the first seal body 31 and the second seal body 51 in order to prevent leakage of the liquid from the shaft seal device 30 can be reduced. As a result, the shaft seal device 30 of the present embodiment can prevent leakage of higher pressure liquid as compared with the shaft seal device 30 shown in FIG. Further, when the shaft seal device 30 of the present embodiment is compared with the shaft seal device 30 shown in FIG. 2, the diameters of the first seal body 31 and the second seal body 51 can be reduced. The size of 30 (in particular, the size of the shaft seal device 30 in the direction perpendicular to the axis of the rotating shaft 6) can be reduced.

The pressure of the liquid existing in the second seal chamber 53 a of the second casing structure 53 is caused between the lower surface 55 b of the second upper casing 55 and the upper surface 51 a of the second seal body 51 by the rotation of the second seal body 51. When the centrifugal force applied to the liquid existing in the gap is higher, the liquid flows into the internal space 48a of the leak cover 48 through the second through hole 55a. However, the liquid that has flowed into the internal space 48 a of the leak cover 48 is returned to the suction water tank 5 via the leak pipe 49. Therefore, the shaft seal device 30 can reliably prevent the liquid from leaking from the shaft seal device 30.

When the shaft seal device 30 has the intermediate seal structure 60, the shaft seal device 30 has an opening 53 b provided on the side wall of the second casing structure 53 or an opening 48 b provided on the side wall of the leak cover 48. Need to have one. More specifically, the opening 53b provided on the side wall of the second casing structure 53 can be omitted. In this case, the liquid leakage cover 48 is fixed to the upper surface of the upper casing 53 of the second casing structure 53, At least one opening 48 b is provided on the side wall of the leak cover 48. Alternatively, the leak cover 48 fixed to the upper surface of the upper casing 53 of the second casing structure 53 and at least one opening 48b provided on the side wall of the leak cover 48 can be omitted. An opening 53 b is provided on the side wall of the second casing structure 53.

Although not shown, the upper seal structure 45 described with reference to FIGS. 9 and 11 may be provided in the shaft seal device 30 shown in FIG. In this case, the upper seal structure 45 can reduce the pressure of the liquid flowing into the internal space 48 a of the leak cover 48.

seal bodies

31, 51 cannot be increased, the liquid is sealed by the plurality of

seal bodies

31, 51. Leakage from 30 can be effectively prevented.

seal bodies

31 and 51 are not in sliding contact with other members, the plurality of

seal bodies

body

Furthermore, the intermediate seal structure 60 is a non-contact type seal in which the sleeve 61 that rotates integrally with the rotary shaft 6 does not contact the first upper casing 35. Therefore, the sleeve 61 and the first upper casing 35 are not worn, and the maintenance frequency of the intermediate seal structure 60 can be greatly reduced. Further, since the intermediate seal structure 60 exhibits a sealing function without contact, frictional heat is not generated, and it is not necessary to supply liquids such as cooling water and flushing liquid to the intermediate seal structure 60.

In the present embodiment, the intermediate seal structure 60 seals the gap between the first through hole 35a that connects the adjacent first seal chamber 33a and second seal chamber 53a to each other and the rotary shaft 6. When the shaft seal device 30 has three or more casing structures and three or more seal bodies accommodated in seal chambers formed in the casing structures, the shaft seal device 30 is It is only necessary to have at least one intermediate seal structure 60. More specifically, the shaft seal device 30 includes at least one intermediate seal structure that seals a gap between at least one through hole among a plurality of through holes that allow adjacent seal chambers to communicate with each other and the rotary shaft 6. The body 60 may be included. In this case, the shaft seal device 30 includes at least one opening provided in a side wall of at least one casing structure and / or a liquid leakage cover 48 fixed to the upper surface of the upper casing of the uppermost casing structure. At least one opening 48b provided on the side wall.

Although not shown, the intermediate seal structure 60 shown in FIG. 12 may be provided in the shaft seal device 30 shown in FIGS. 7, 8, 9, and 11.

Although not shown, the upper surface 31a of the first seal body 31 and / or the upper surface 51a of the second seal body 51 shown in FIG. 9, FIG. 10, FIG. 11, and FIG. You may make it incline below toward the radial direction outer side of the 2nd seal body 51 (refer FIG. 7). Similarly, the upper surface 31a of the first seal body 31 and / or the upper surface 51a of the second seal body 51 shown in FIG. 9, FIG. 10, FIG. 11, and FIG. The seal body 51 may be inclined downward and radially curved toward the outer side in the radial direction (see FIG. 8).

In the above-described embodiment, the plurality of

seal bodies

31 and 51 of the shaft seal device 30 do not come into contact with other members, so that no abrasion powder is generated from each

seal body

31 and 51. Similarly, since the upper seal structure 45, the lower seal structure 40, and the intermediate seal structure 61 are also non-contact type seals, the upper seal structure 45, the lower seal structure 40, and the intermediate seal structure No wear powder is generated from 61. Therefore, the shaft seal device 30 according to the above-described embodiment can be attached to a vertical shaft pump that transfers a liquid (for example, drinking water) that requires strict quality.

The above-described embodiments are described for the purpose of enabling the person having ordinary knowledge in the technical field to which the present invention belongs to implement the present invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Accordingly, the present invention is not limited to the described embodiments, but is to be construed in the widest scope according to the technical idea defined by the claims.

The present invention can be used for a shaft seal device that prevents liquid from leaking from a shaft penetration portion of a container through which a rotating shaft penetrates. Further, the present invention can be used for a vertical shaft pump provided with this shaft seal device.

DESCRIPTION OF SYMBOLS 1 Impeller casing 2 Pump casing 3 Pumped pipe 4 Discharge elbow pipe 5 Suction water tank 6 Rotating shaft 10 Impeller 11 Outer bearing 12 Underwater bearing 15 Intermediate bearing 20 Discharge piping 22 Pump installation floor 23 Installation base 25 Gate valve 30 Shaft seal device 31 First seal body 33 First casing structure 34 Lower casing 35 First upper casing 36 First intermediate casing 37 Groove 40 Lower seal structure 41 Sleeve 43 Drain pipe 45 Upper seal structure 47 Sleeve 48 Leakage cover 49 Leakage Liquid pipe 50 Drain plate 51 Second seal body 53 Second casing structure 55 Second upper casing 56 Second intermediate casing 70 Seal casing 100 Discharge water tank

Claims

A shaft seal device that is fixed to a container that separates a high-pressure fluid and a low-pressure fluid and seals a shaft penetration portion of a rotating shaft that extends through the container,
A sealed casing having a plurality of casing structures disposed along the axial direction of the rotating shaft;
A plurality of seal chambers formed inside each of the plurality of casing structures;
A plurality of disk-shaped sealing bodies that are housed in each of the plurality of seal chambers, rotate integrally with the rotation shaft, and have an annular surface perpendicular to the axis of the rotation shaft;
Each of the plurality of casing structures has a through hole through which the rotating shaft passes and communicates with the seal chamber;
A shaft seal device, wherein an inner surface of the casing structure that faces the annular surface of the seal body and forms the seal chamber is a plane perpendicular to the axis of the rotation shaft.
A plurality of radially extending grooves are formed in the annular surface of at least one of the plurality of seal bodies,
The shaft seal device according to claim 1, wherein the width of the groove is constant from the inner end to the outer end of the groove.
A plurality of radially extending grooves are formed in the annular surface of at least one of the plurality of seal bodies,
The shaft seal device according to claim 1, wherein the width of the groove gradually increases toward an outer end of the groove.
Above the seal body located at the uppermost side of the plurality of seal bodies, a gap between the through hole of the seal structure body located at the uppermost side of the plurality of seal structures and the rotary shaft is sealed. The shaft seal device according to any one of claims 1 to 3, further comprising a non-contact upper seal structure.
The upper seal structure is a labyrinth seal or a flat seal,
A liquid leakage cover fixed to an upper portion of the seal casing so as to surround the upper seal structure is provided;
The leak cover is provided with an opening that communicates the internal space of the leak cover with the outside of the leak cover,
The shaft seal device according to claim 4, wherein a leak pipe is connected to the opening.
Below the lowermost seal body of the plurality of seal bodies, there is a gap between the through hole of the lowermost seal structure body of the plurality of seal structures and the rotating shaft. The shaft seal device according to any one of claims 1 to 5, further comprising a non-contact-type lower seal structure for sealing.
The shaft seal device according to claim 6, wherein the lower seal structure is a rabin rinse seal or a flat seal.
The seal casing is provided with at least one opening that communicates at least one seal chamber of the plurality of seal chambers with the outside of the seal casing;
The shaft seal device according to claim 6 or 7, wherein a drain pipe is connected to the opening.
A shaft seal device that is fixed to a container that separates a high-pressure fluid and a low-pressure fluid and seals a shaft penetration portion of a rotating shaft that extends through the container,
A sealed casing having a plurality of casing structures disposed along the axial direction of the rotating shaft;
A plurality of seal chambers formed inside each of the plurality of casing structures;
A plurality of disc-shaped seal bodies that are housed in each of the plurality of seal chambers and rotate integrally with the rotation shaft,
Each of the plurality of casing structures has a through hole through which the rotating shaft passes and communicates with the seal chamber;
The seal body has an upper surface that is inclined downward with respect to a plane perpendicular to the axis of the rotating shaft,
The shaft seal device, wherein an inner surface of the casing structure that faces the upper surface of the seal body and forms the seal chamber extends along the upper surface of the seal body.
The shaft seal device according to claim 9, wherein the upper surface of the seal body is curved.
Impeller,
A rotating shaft to which the impeller is fixed;
A pump casing that houses the impeller and has a shaft penetrating portion through which the rotating shaft passes;
A shaft sealing device for sealing the shaft penetrating portion,
The shaft seal device is
A sealed casing having a plurality of casing structures disposed along the axial direction of the rotating shaft;
A plurality of seal chambers formed inside each of the plurality of casing structures;
A plurality of disk-shaped sealing bodies that are housed in each of the plurality of seal chambers, rotate integrally with the rotation shaft, and have an annular surface perpendicular to the axis of the rotation shaft;
Each of the plurality of casing structures has a through hole through which the rotating shaft passes and communicates with the seal chamber;
The vertical shaft pump, wherein an inner surface of the casing structure that faces the annular surface of the seal body and forms the seal chamber is a plane perpendicular to the axis of the rotation shaft.
Impeller,
A rotating shaft to which the impeller is fixed;
A pump casing that houses the impeller and has a shaft penetrating portion through which the rotating shaft passes;
A shaft sealing device for sealing the shaft penetrating portion,
The shaft seal device is
A sealed casing having a plurality of casing structures disposed along the axial direction of the rotating shaft;
A plurality of seal chambers formed inside each of the plurality of casing structures;
A plurality of disc-shaped seal bodies that are housed in each of the plurality of seal chambers and rotate integrally with the rotation shaft,
Each of the plurality of casing structures has a through hole through which the rotating shaft passes and communicates with the seal chamber;
The seal body has an upper surface that is inclined downward with respect to a plane perpendicular to the axis of the rotating shaft,
An upright shaft pump characterized in that an inner surface of the casing structure which faces the annular surface of the seal body and forms the seal chamber extends along the upper surface of the seal body.