JP2009243321A - Seal device and pump having the seal device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable seal device and a pump, for maintaining a stable sliding characteristic and sealability over a long period, by surely preventing an inclination of a seat ring for sliding with a seal ring, when sealing a high pressure fluid. <P>SOLUTION: This seal device includes a flange fixed to a rotary shaft, the seal ring fixed to this flange, a housing having a cover arranged outside the rotary shaft so as to surround the flange, the seat ring for sliding with the seal ring and a stationary ring for pressing this seat ring. A metallic ring having a hole part for inserting a pin arranged in the stationary ring, is arranged on the outer peripheral side of the seat ring, and the seat ring is independently arranged to the stationary ring. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pump sealing device for sealing a high-pressure fluid.

  In recent years, the pump capacity has been increased and the head height has been increased. For this reason, the seal device that prevents the fluid from leaking from the rotary shaft portion of the pump is required to have an ability to be used in an environment where a high-pressure fluid acts.

  As a shaft seal device for a rotary shaft in a hydraulic machine, a device using ceramics for upper and lower seal rings is disclosed in Japanese Patent Laid-Open No. 5-203064 (Patent Document 1). In this shaft seal device, an arcuate curved surface is provided at the outer end portion of the flat seal portion of the upper seal ring, and the flat seal portion and the side surface are smoothly connected. For this reason, the outer end of the lower seal ring is rotated even if a slight inclination occurs in the seal surfaces of the lower seal ring and the upper seal ring due to rotation of the rotary shaft and deformation due to shaft runout or water pressure of the rotary shaft. The shaft seal function is maintained to ensure that the outer end of the upper seal ring does not collide with each other and the outer ends are always in smooth contact with each other so that the pressure water on the runner side does not leak outside. And improve safety.

  On the other hand, as a shaft seal device of a vertical shaft pump, an end face type ceramic shaft seal device using ceramics as a seal ring material as disclosed in Japanese Patent Application Laid-Open No. 8-284880 (Patent Document 2) is used. It has become. This end face type ceramic shaft seal device provides a shaft seal device that uses pumped liquid as lubricating water, is stable for a long time, and can be operated repeatedly in the air without the need for external water supply. Stable sliding characteristics are ensured by preventing the intrusion or accumulation of water.

JP-A-5-203064 JP-A-8-284880

  However, in the shaft seal device described in Patent Document 1, even if the seal surfaces of the lower seal ring and the upper seal ring are inclined due to deformation due to water pressure, the outer end portion of the lower seal ring and the upper seal ring The shaft seal function is maintained so that it does not come into contact with the outer end of the shaft, but the tilt amount of each sealing surface changes according to the hydraulic pressure condition, so it is familiar that it does not slide at the same location. hard. As a result, it is expected that stable sliding characteristics cannot be secured.

  On the other hand, in the shaft seal device of the vertical shaft pump described in Patent Document 2, the seal ring 52 is stored in the case 51 fixed to the seal case 50 as shown in FIG. The horizontal portion 50a of the seal case 50 is curved. For this reason, the seal ring 52 stored in the case 51 is also inclined, and only the outer portion of the seal ring 52 slides with the lower seal ring 53. In such a sliding state, the contact portion at one piece becomes an excessive surface pressure state, and wear damage may progress early. As a result, it can be estimated that it is difficult to maintain stable sliding characteristics over a long period of time.

  As described above, in the known example, when it is assumed that a high-pressure fluid is sealed, the prevention of wear damage due to the inclination of the seal ring and the stabilization of the sliding characteristics are not sufficiently considered. There is a possibility that stable sealing performance and sliding characteristics cannot be maintained over a long period of time.

  The present invention has been made in view of the circumstances as described above, and the object of the invention is to reliably prevent tilting of the seal ring and ensure stable sealing performance even when sealing a high-pressure fluid. The object is to obtain a highly reliable sealing device and a pump equipped with the sealing device.

  In order to achieve the above object, a sealing device of the present invention is arranged so as to surround a flange fixed to the rotary shaft, a seal ring fixed to the flange, and outside the rotary shaft. In a sealing device comprising a housing having a cover, a seat ring that slides with the seal ring, and a stationary ring that presses the seat ring, a hole portion into which a pin provided in the stationary ring is inserted The metal ring is provided on the outer peripheral side of the seat ring, and the seat ring is provided independently of the stationary ring.

  In order to achieve the above object, a pump according to the present invention is a pump casing having a rotating shaft, an impeller fixed to the lower end of the rotating shaft, and a passage for fluid inside the rotating shaft. And a seal device for preventing leakage from a gap between the pump casing and the rotary shaft, wherein the seal device includes a flange fixed to the rotary shaft, and a seal fixed to the flange. A seal device comprising: a ring, a housing having a cover arranged so as to surround the flange on the outer side of the rotating shaft; a seat ring that slides with the seal ring; and a stationary ring that presses the seat ring A metal ring having a hole into which a pin provided in the stationary ring is inserted is provided on an outer peripheral side of the seat ring, and the seat ring is opposed to the stationary ring. Those provided independently Te.

  According to the present invention, sealing performance and sliding characteristics can be stabilized, and a highly reliable sealing device can be obtained, which can be used as a sealing device for a high-pressure pump.

  Embodiments of the present invention will be described below with reference to the drawings. In the second and subsequent embodiments, the duplicate description of the configuration common to the first embodiment is omitted. In addition, the same code | symbol in the figure of each Example shows the same thing or an equivalent. Here, the case where silicon carbide, which is a ceramic material, is used as the material used for the seal ring 4 and the seat ring 7 described later will be described. The material is not particularly limited as long as it is a material exhibiting wear resistance.

  FIG. 1 shows a cross-sectional structure of a sealing device 40 in the present embodiment. A disc-shaped flange 2 is fixed to the rotary shaft 1. On the upper surface of the flange 2, a case 3 provided on the flange 2 and a seal ring 4 stored in the case 3 are provided. The seal ring 4 passes through the case 3 with bolts (not shown) with respect to the flange 2. It is fixed.

  A housing 6 is arranged so as to surround the outside of the flange 2 fixed to the rotating shaft 1. A cover 5 is provided on the upper surface of the housing 6. The seat ring 7 is installed in a state of contacting the seal ring 4. In this embodiment, the seal ring 4 and the seat ring 7 are made of the same ceramic material.

  The upper surface of the seat ring 7 is pressed by the stationary ring 8, but is arranged independently of the stationary ring 8. The stationary ring 8 is a member having an L-shaped cross section, and includes a cylindrical portion parallel to the rotation shaft 1 and a flange portion parallel to the flange 2. The seat ring 7 is pressed in contact with a flange portion parallel to the flange 2 which is a horizontal portion of the stationary ring 8.

  A seal member 9 having elasticity is mounted in a gap between the cylinder portion of the stationary ring 8 parallel to the rotation shaft 1 and the cover 5.

  In order to always bring the stationary ring 8 into contact with the upper surface of the seat ring 7, the surface opposite to the contact surface with the seat ring 7 in the flange parallel to the flange 2 of the stationary ring 8 is separated from the cover 5. A coil spring 10 for generating force is provided, and the stationary ring 8 presses the seat ring 7 toward the seal ring 4 by the coil spring 10. A plurality of coil springs 10 are installed in the circumferential direction on the collar portion of the stationary ring 8.

  A metal ring 11 is shrink-fitted and fixed to the outer peripheral side of the seat ring 7. In order to prevent the seat ring 7 from rotating, a pin 12 fixed to the stationary ring 8 is inserted into the communication hole 14 of the metal ring 11. By the rotation prevention mechanism for the seat ring 7 including the pin 12 and the communication hole 14, the seat ring 7 slides on the seal ring 4 without rotating in conjunction with the seal ring 4 rotating along with the rotating shaft 1.

  Further, a support member 13 is installed in a gap between the outer peripheral portion of the metal ring 11 and the inner peripheral portion of the housing 6 for positioning the communication hole sheet ring 7. The stationary ring 8 is held through a cover 5 and a seal member 9 so as to be capable of relative movement so that the vertical movement of the rotary shaft 1 can be followed.

  In this sealing device 40, a high-pressure fluid acts on a portion surrounded by the flange lower surface 2A, the rotary shaft 1 and the housing 6, and the fluid leaks from the sliding surface where the seal ring 4 and the seat ring 7 are in contact. Go. Here, the arrows in the figure indicate the flow direction of the high-pressure fluid.

  FIG. 2 shows a cross-sectional structure of the sealing device after the high pressure fluid has acted. The operation of the sealing device 40 in this embodiment will be described with reference to FIG.

  In the sealing device 40, deformation of the stationary ring 8 in which the horizontal portion of the stationary ring 8 is curved occurs due to the action of the high-pressure fluid. Therefore, the horizontal portion lower surface 8A of the stationary ring 8 is also curved. On the other hand, since the seat ring 7 is independent of the stationary ring 8, the seat ring 7 is maintained in a substantially horizontal state without being affected by the bending deformation of the stationary ring 8. Therefore, the seat ring sliding surface 7A in contact with the seal ring 4 is in a substantially horizontal state, and a substantially uniform contact state with the sliding surface of the seal ring 4 is maintained. Thereby, uneven wear of the sliding surface can be avoided, and stable sliding characteristics can be obtained.

  Incidentally, only the vicinity of the outer periphery of the lower surface 8A of the horizontal portion of the stationary ring 8 comes into contact with the upper surface 7B of the seat ring, and a wedge-shaped gap is formed on the inner peripheral side of the lower surface 8A of the horizontal portion. Since the high pressure fluid is prevented from leaking at the contact portion in the vicinity, the shaft seal function can be maintained.

  Since fluid always intrudes into the wedge-shaped gap to avoid an oxygen deficient state, even if a potential difference occurs between the stationary ring 8 and the seat ring 7, corrosion due to this potential difference can be prevented and high reliability can be achieved. Contribute to. On the other hand, the contact area between the seat ring 7 and the stationary ring 8 is smaller than that of the sealing device in the prior art and the contact surface pressure is increased. However, when a ceramic material is used as a sliding member as in this embodiment, the compression is reduced. High reliability can be ensured because of its high strength and sufficient load resistance.

  Since the sheet ring 7 is shrink-fitted with a metal ring 11 on the outer side to apply a compressive stress, the strength reliability is improved and it is difficult to break. Further, since the seat ring 7 is substantially held at the center position in the horizontal direction by the support member 13, the seat ring 7 slides with the sliding surface of the opposing seal ring 4 with a uniform contact pressure. For this reason, the sliding surfaces of the seal ring 4 and the seat ring 7 are easy to adapt, and as a result, a smooth sliding surface is formed. Once a smooth surface is formed, since both the seal ring 4 and the seat ring 7 are made of the same material, wear hardly progresses and a stable sliding surface is maintained for a long time.

  Next, the action on the seat ring 7 will be described using the pressure distribution acting on the seat ring 7 shown in FIG. P in the figure indicates the pressure of the high-pressure fluid. W represents the pressing force of the stationary ring. The fluid pressure P acts uniformly on the outer peripheral side of the seat ring. Further, since the sliding surface is a parallel plane, a triangular pressure distribution is obtained. In this way, the force acting on the seat ring acts to shrink the seat ring in the vertical direction and the inner diameter direction. Therefore, the outer peripheral side is slightly shrunk in the vertical direction, and the inner peripheral side (atmosphere side) comes into contact with the sliding form so that contact with the outer side is prevented and stable sliding characteristics are obtained. .

  FIG. 4 shows a second embodiment of the sealing device 40 according to the present invention. This embodiment is different from the first embodiment in that an O-ring 15 is attached to an outer portion where the upper surface of the outer periphery of the seat ring 7 on the lower surface of the stationary ring 8 contacts.

  According to this embodiment, basically the same operation and effect as the first embodiment described above can be obtained, and since the O-ring 15 functions as a seal member, the contact between the stationary ring 8 and the seat ring 7 is achieved. The amount of water leakage from the surface can be reduced. As a result, the overall amount of water leakage can be reduced, which can contribute to an improvement in sealing performance.

  Moreover, since the part which guides the seat ring 7 becomes two places, it can support more stably, without changing the position of the seat ring 7, compared with the case where it supports only with the support member 13. FIG. Therefore, stabilization of the contact state between the sliding surfaces of the seal ring 4 and the seat ring 7 can be achieved, which can greatly contribute to improvement of durability reliability.

  FIG. 5 shows a third embodiment of the sealing device 40 according to the present invention. This embodiment is different from the first embodiment in that a step portion 16 is provided on the upper and lower surfaces of the seat ring 7 on the housing 6 side so as to provide a surface away from the opposing surface of the stationary ring 8 and the seal ring 4. is there.

  According to this embodiment, basically the same operational effects as the first embodiment described above can be obtained, and the contact width between the sliding surface of the seal ring 4 and the stationary ring 8 is narrowed. Machining finishing accuracy can be easily improved, saving processing costs and reducing costs. In addition, since it is always cooled by the sealing fluid outside the step portion 16, heat dissipation can be improved, and it is possible to set a high surface pressure for the sliding surface with the stationary ring 8 to press the stationary ring 8, The pressure condition of the sealing fluid can be increased, which can contribute to the expansion of the application range of the sealing device 40.

  FIG. 6 shows a fourth embodiment of the sealing device 40 according to the present invention. This embodiment is different from the first embodiment in that a step 16 is provided on the upper and lower surfaces of the seat ring 7 on the side of the housing 6 to provide a surface away from the opposed surface of the stationary ring 8 and the seal ring 4, and the seat ring 7 is that the O-ring 15a is mounted on the seat ring 7 side where the step 16 on the upper surface 7 and the stationary ring 8 contact.

  According to this embodiment, basically the same operational effects as those of the first embodiment described above can be obtained, and the contact width between the sliding surface of the seal ring 4 and the stationary ring 8 is narrowed. Accuracy can be obtained in a short time, which is effective in reducing processing costs. Further, since the O-ring 15a is attached, the sealing performance can be improved.

  FIG. 7 shows a fifth embodiment of the sealing device 40 according to the present invention. This embodiment is different from the first embodiment in that the seal ring 41 is directly attached and fixed to the flange 2 fixed to the rotary shaft 1. An O-ring 15b is attached to a portion where the rotating shaft 1 and the seal ring 41 are in contact with each other. An O-ring 15 c is attached to the groove 17 of the flange 2 on the outer peripheral side of the seal ring 41.

  According to this embodiment, basically the same effects as those of the first embodiment described above can be obtained, and when the seal ring 4 is damaged and needs to be replaced, it is removed from the case 3. Since there is no work process for re-fixing and the replacement can be performed directly, the replacement work can be easily performed in a short time, and the replacement cost can be saved.

  Next, the case where the sealing device of this embodiment is mounted on a high-pressure vertical pump will be described with reference to FIG. Here, a high pressure pump having a bearing that supports a rotating shaft in a pump casing that constitutes a flow path will be described. However, even when a bearing is disposed outside the pump casing, the sealing device is a rotating shaft portion. It is installed for preventing water leakage from the gap between the fixed portion and the arrangement and structure of the bearing used in the high-pressure pump.

  The high-pressure vertical shaft pump shown in FIG. 8 has a rotary shaft 1, an impeller 31 fixed to the lower end of the rotary shaft 1, and a pump casing 32 that passes through the rotary shaft 1 and has a fluid passage formed therein. And a sealing device 40 for preventing leakage from the gap between the pump casing 32 and the rotary shaft 1, and a motor 34 for driving the rotary shaft 1 via the coupling 33. The rotating shaft 1 is supported by two bearings 35 installed in the flow path of the pump casing 32.

  In the sealing device 40, as described above, the disc-shaped flange 2 is fixed to the rotary shaft 1, and the housing 6 is disposed so as to surround the outside of the flange 2.

  The seal device 40 in FIG. 8 has the structure in the embodiment of the present invention as described above, and the seal ring 4 and the seat ring 7 are made of the same ceramic material.

  By using the sealing device 40, the sliding surface of the seat ring 7 that comes into contact with the sealing ring 4 is in a substantially horizontal state, and a substantially uniform contact state is maintained, so that the sliding surface between the sealing ring 4 and the seat ring 7 is maintained. Therefore, stable sliding characteristics can be obtained.

  Therefore, stable sliding characteristics and sealing performance can be obtained even under the action of a high-pressure fluid, so that it can be used as a sealing device for a high-pressure pump.

  As described above, according to the present embodiment, the seal ring 4, the seat ring 7 in which the metal ring 11 is shrink-fitted on the outer peripheral side, and the stationary ring 8 are arranged independently of each other. Therefore, even if the horizontal portion of the stationary ring 8 is bent by the action of a high-pressure fluid, the sliding surface of the seat ring 7 can be held in a substantially parallel state without tilting the independent seat ring 7, and the outer contact can be achieved. Is avoided.

  Further, since the seat ring 7 on which the metal ring 11 is shrink-fitted can be held at the same position by the support member 13 installed in the gap with the housing 6, the position facing the seal ring 4 becomes the same position. A familiar surface can be obtained early. Therefore, the sliding characteristics can be stabilized, the wear resistance of the sliding surface can be maintained over a long period of time, and a highly reliable sealing device 40 can be obtained, which can be mounted as a high pressure pump sealing device. .

  In addition, the seal ring 4 and the seat ring 7 are made of the same material, in particular, a ceramic material, so that the sliding surfaces of the seal ring 4 and the seat ring 7 pass through the same conforming process and are smoothed to form a favorable sliding surface. The Ceramics have high wear resistance, so that it is possible to prevent changes in the shape of the sliding surface with respect to long-term use, and a stable shaft sealing function can be maintained continuously from the beginning of operation. Further, since the thermal deformation of the sliding surface is also symmetrical, it is possible to avoid uneven wear of either the seal ring 4 or the seat ring 7.

The longitudinal cross-sectional view of the sealing device in one Example of this invention. The longitudinal cross-sectional view at the time of a high pressure fluid acting with the sealing device of FIG. Explanatory drawing which shows the pressure distribution which acts on a seat ring. Sectional drawing which shows the other Example of the sealing apparatus of this invention. Sectional drawing which shows the other Example of the sealing apparatus of this invention. Sectional drawing which shows the other Example of the sealing apparatus of this invention. Sectional drawing which shows the other Example of the sealing apparatus of this invention. Explanatory drawing which shows the state which applied the sealing apparatus of this invention to the vertical shaft pump. Sectional drawing for demonstrating the case where a high pressure fluid acts with the conventional sealing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotating shaft 2 Flange 3 Case 4, 41 Seal ring 5 Cover 6 Housing 7 Seat ring 8 Stationary ring 9 Seal member 10 Coil spring 11 Metal ring 13 Support member 14 Communication hole 15, 15a, 15b, 15c O-ring 16 Step part 17 Groove 31 Impeller 32 Pump casing 33 Coupling 34 Motor 35 Bearing 40 Sealing device

Claims (4)

  A flange fixed to the rotary shaft, a seal ring fixed to the flange, a housing including a cover arranged to surround the flange outside the rotary shaft, and a seat that slides on the seal ring In a sealing device comprising a ring and a stationary ring that presses the seat ring, a metal ring having a hole into which a pin provided in the stationary ring is inserted is provided on the outer peripheral side of the seat ring, A seal device, wherein a seat ring is provided independently of the stationary ring.   The sealing device according to claim 1, wherein a support member that supports the seat ring is provided in a gap between the metal ring and the housing.   2. The sealing device according to claim 1, wherein the seal ring and the seat ring are made of the same ceramic material.   A rotary shaft, an impeller fixed to the lower end of the rotary shaft, a pump casing that passes through the rotary shaft and has a fluid flow path therein, and leakage from a gap between the pump casing and the rotary shaft In the pump including the sealing device for preventing the sealing, the sealing device surrounds the flange on the outer side of the rotary shaft, a flange fixed to the rotary shaft, a seal ring fixed to the flange, and A hole in which a pin provided in the stationary ring is inserted in a sealing device including a housing having a cover arranged, a seat ring that slides with the seal ring, and a stationary ring that presses the seat ring. A metal ring having a portion is provided on an outer peripheral side of the seat ring, and the seat ring is provided independently of the stationary ring.

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