JP2006170091A - Shaft seal device for slurry pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shaft seal device for a slurry pump having high shaft seal effect and long durability time. <P>SOLUTION: This device consists of a plurality of lip seals 11. The lip seal is installed one by one to have a V-shape pressure receive part 16 oriented to a pump casing side, and a lantern ring 20 is arranged behind the lip seals 11. Shaft sealing water with a pressure higher than the pressure in the pump casing is supplied to the lantern ring 20, and grease or lubricating oil is supplied to the lantern ring arranged at the farthest position from the pump casing. A back up part 23 having a shape corresponding to a tapered part 14 of the lip seal is formed in front of the lantern ring. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a slurry pump comprising an impeller and a pump casing, and when a rotary shaft to which the impeller is attached is rotationally driven, slurry sucked from the suction port is pumped from the discharge port. The shaft is suitable for a shaft seal device of a slurry pump particularly used in a muddy water shield method, although it is related to a shaft seal device in a portion where the rotary shaft passes through the pump casing. The present invention relates to a sealing device.

  Centrifugal pumps or slurry pumps are well known in the art without mentioning their literature names. Pump casings, impellers that are driven to rotate in the pump casings, rotating shafts to which the impellers are attached, and rotating the rotating shafts. The bearing comprises a bearing box, a packing box provided at a portion where the rotary shaft passes through the pump casing, that is, a staffin box. Therefore, when the rotary shaft is driven to rotate by the electric motor, the slurry is sucked from the side of the pump casing by the rotation of the impeller, the velocity energy is given by the centrifugal force, and the pressure energy or the pressure until reaching the discharge port of the pump casing. Converted to pressure head. Subsequently, it discharges from the discharge port provided in the radius outer side of the pump casing.

  Thus, when the slurry is pumped, the pressure in the pump casing increases, so a shaft seal device is provided at the portion where the rotating shaft passes through the pump casing to prevent the slurry from leaking into the atmosphere. It has been. As a shaft seal device, a mechanical seal is also known, but Patent Document 1 discloses a gland packing. That is, the shaft seal device of the rotating shaft that penetrates the pump casing is composed of a gland packing and prevents liquid leaking from this gland packing, that is, seawater, from splashing around and prevents overheating and abnormal wear of the shaft seal. A shaft seal device is shown. Patent Document 2 discloses a shaft seal device for a slurry transport pump in which an oil seal, that is, a lip seal is packed in a staffin box.

Japanese Patent Laid-Open No. 8-200285 JP 2004-108228 A

  As a prior art of the present invention, a shaft seal device as shown in FIG. 3 is known. FIG. 3 is a cross-sectional view schematically showing only the main part of the shaft seal device of the slurry pump. In FIG. 3, reference numeral 40 indicates a rotation shaft, and the impeller is screwed into the tip of the rotation shaft 40. It is like that. A shaft sleeve 41 is mounted on the outer periphery of the rotating shaft 40, and in the example shown in FIG. 3, four lip seals 43, 43e,... Are provided between the outer periphery of the shaft sleeve 41 and the packing box 42. Is provided. Two gland packings 46a and 46b are provided on the packing presser 45 side. A shaft seal water ring 47 is provided between the leftmost lip seal 43e and the rightmost gland packing 46b. The lip seals 43, 43e,... Have a cross-section from a first lip portion 50 that dynamically frictionally contacts the shaft sleeve 41 and a second lip portion 51 that contacts the inner peripheral surface of the packing box 42 in a fixed manner. The shape is configured to be substantially V-shaped when viewed from the side. The shaft seal water 47 is supplied with a shaft seal water higher than the pressure of the slurry in the pump casing from the pipe 48.

  According to the shaft seal device shown in FIG. 3, the lip seal 43 has a V-shaped cross section, and the first lip portion 50 on the inner peripheral side is in dynamic contact with the shaft sleeve 41 to check the check valve. Thus, slurry leakage is prevented to some extent. Further, since the shaft seal water is supplied from the shaft seal water ring 47, particularly the first lip portion 50 of the lip seal 43 is cooled, and the solid matter is washed away. Thus, although the conventional shaft seal device has many advantages, it should be recognized that it should be improved. For example, since the lip seals 43, 43,... Are made of synthetic resin and have low rigidity, when a high pressure is applied from the pump casing, the first lip portion 50 is deformed radially inward to the shaft sleeve 41. Increases contact area. As the area increases, the frictional heat increases and the durability is impaired. Of course, since the shaft seal water is supplied from the shaft seal water ring 47, the frictional heat can be suppressed to some extent, but since only one shaft seal water ring 47 is provided at a location far from the pump casing, there is a possibility of spreading. The lip seal near the pump casing may not reach. For these reasons, the conditions required for the shaft seal device of a small slurry pump with a high head cannot be satisfied. More specifically, a slurry pump is used for the mud shield method in tunnel excavation, but since such a slurry pump is installed in a limited space in the tunnel, a small pump is desired. It is rare. In addition, tunnel depth and long-distance excavation become larger, and a high-pump slurry pump is used to perform high-pressure operation and high-speed operation. By the way, when the lift becomes high, the working pressure to the shaft seal device becomes high, and the amount of solids invading and the amount of remaining amount also increase. When rotating at high speed in such a state, the sliding contact speed of the seal lip increases and the amount of heat generation also increases. This impairs the durability of the seal lip.

  An object of the present invention is to provide a shaft seal device for a slurry pump that solves the above-mentioned conventional problems. Specifically, the shaft seal of a slurry pump having a high shaft seal effect and a long durability time is provided. The object is to provide a device.

  In order to achieve the above object, a plurality of lip seals are applied to the present invention. The lip seal is provided between a shaft sleeve attached to the outer peripheral surface of the rotary shaft of the pump and the staffin box. The lip seal has a substantially V-shaped cross section when viewed from the side, from a first lip portion that dynamically frictionally contacts the shaft sleeve and a second lip portion that statically contacts the inner peripheral surface of the staffin box. It is integrally formed so as to exhibit a letter shape. The outer peripheral surface of the first lip portion is formed so as to have a tapered portion that increases in diameter as it moves away from the pump casing, or is separated from the shaft sleeve. The lip seal configured as described above is formed of, for example, nitrile butyl rubber. Further, the present invention also applies a plurality of shaft sealing water rings, that is, lantern rings, between a plurality of lip seals. The lantern ring is formed between non-rust steels, for example, so as to have a tapered backup portion provided between the lip seals and supporting the tapered portion of the lip seal. The lantern ring configured as above is supplied with shaft seal water higher than the pressure in the pump casing.

  Thus, in order to achieve the above-mentioned object, the invention according to claim 1 is a slurry that is composed of an impeller and a pump casing and is sucked from the suction port when the rotary shaft to which the impeller is attached is driven to rotate. Is a shaft seal device of a portion of the slurry pump in which the rotary shaft passes through the pump casing, and the shaft seal device is attached to the rotary shaft. The lip seal includes a plurality of lip seals and a plurality of lantern rings provided between the outer peripheral surface of the shaft sleeve and the inner peripheral surface of the staffin box. From the first lip portion that dynamically contacts the outer peripheral surface of the shaft sleeve, and the second lip portion whose outer peripheral surface statically contacts the inner peripheral surface of the staffin box, the first lip portion The second lip portion is formed with a pressure receiving portion that opens in a substantially V shape on the pump casing side, and the first lip portion has a diameter that increases from the dynamically contacting portion toward the rear. These lip seals are integrally formed so as to have a tapered portion, and these lip seals are sequentially mounted so that the pressure receiving portion faces the pump casing side, and the lantern ring is disposed behind the lip seals. The lantern ring disposed farthest from the pump casing and pressed by a seal presser having a sealing means is supplied with grease or lubricating oil, and the other lantern rings are supplied with pressure in the pump casing. Higher shaft seal water is supplied. According to a second aspect of the present invention, in the shaft seal device according to the first aspect, a backup portion having a shape corresponding to the tapered portion of the first lip portion of the lip seal is formed in front of the lantern ring. .

  As described above, according to the present invention, in the slurry pump, a plurality of lip seals and a plurality of lip seals provided between the outer peripheral surface of the shaft sleeve mounted on the rotating shaft and the inner peripheral surface of the staffin box. The lip seal has a first lip portion whose inner peripheral surface is dynamically in contact with the outer peripheral surface of the shaft sleeve, and the outer peripheral surface is an inner peripheral surface of the staffin box. The first and second lip portions are formed with a pressure receiving portion that opens in a substantially V shape on the pump casing side, and the second lip portion that statically contacts the surface. The lip portion is integrally formed so as to have a taper portion whose diameter increases rearward from the dynamically contacting portion, and these lip seals have the pressure receiving portion facing the pump casing side. The lantern rings are sequentially mounted, the lantern rings are arranged behind these lip seals, are arranged farthest from the pump casing, and are pressed by a seal presser having a sealing means. Alternatively, lubricating oil is supplied and shaft sealing water higher than the pressure in the pump casing is supplied to the other lantern rings, so that the shaft sealing water pushes the first lip portion of the lip seal. Open and try to flow towards the pump casing. Thereby, leakage of the slurry is effectively prevented. At the same time, the intrusion of the solid matter is prevented, the solid matter that has entered is washed away, and further, the first lip portion of the lip seal is also cooled, so that an effect unique to the present invention can be obtained. In addition, grease or lubricating oil is separately supplied to the lantern ring that is arranged farthest from the pump casing and is pressed by the seal presser. At this time, the seal presser is provided with a sealing means, so supply Grease or lubricating oil is prevented from escaping to the atmosphere. This prevents wear of the lip seal. That is, it is possible to prevent wear due to heat generation and to prolong the life of the entire shaft seal device. In the invention according to claim 2, since the backup portion having a shape corresponding to the taper portion of the first lip portion of the lip seal is formed in front of the lantern ring, in addition to the above effects, The effect of preventing the lip seal from spreading due to the pressure of the slurry is further obtained.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. Since the slurry pump 1 according to the present embodiment is configured as conventionally known except for the shaft seal portion, the detailed description is omitted, but the impeller 2 is provided. The impeller 2 is attached by screwing into the tip of the rotating shaft 4 that passes through the pump casing 3. A suction cover 6 is attached to face the pump casing 3. The rear end portion of the rotary shaft 4 is rotatably supported by a bearing 8 and is driven to rotate by an electric motor. Therefore, when the rotary shaft 4 is rotationally driven, the impeller 2 is rotationally driven in the pump casing 3, the slurry is sucked from the suction port 7 of the suction cover 6, kinetic energy is given by the centrifugal force of the impeller 2, and It is discharged or pumped from the discharge port 9 of the pump casing 3.

  Thus, since the rotating rotating shaft 4 passes through the fixed pump casing 3, there is a gap between them, and the slurry pressurized in the pump casing 3 leaks to the atmosphere side on the low pressure side. . Therefore, the shaft seal device 10 is provided in the penetrating portion. According to the embodiment shown in FIG. 1, the shaft seal device 10 includes four lip seals 11, 11,..., And four lip seals 11, 11,. It comprises a lantern ring 20, 20e,... And a shaft seal water supply unit 30. More specifically, the shaft sleeve 5 is inserted in the outer peripheral portion of the rotating shaft 4 between the rear end portion of the pump casing 3 and the bearing 6. .. Are attached between the shaft sleeve 5 and the staffin box 28. The four lip seals 11, 11,. 2A is a cross-sectional view showing a part of the shaft seal device 10 in an enlarged manner. In FIG. 2, the right side is the pump casing side, but the lip seal 11 is as shown in FIG. The cross-sectional shape is substantially V-shaped when viewed from the side. That is, the lip seal 11 is statically in contact with the first lip portion 12 where the distal end portion 13 of the outer peripheral surface thereof is in frictional contact with the shaft sleeve 5 and the inner peripheral surface of the staffin box 28. The second lip portion 15 is integrally formed. The distal end portion 13 of the inner peripheral surface of the first lip portion 12 is in contact with the shaft sleeve 5, but as the distance from the pump casing 3 increases, the inner diameter increases and becomes a tapered portion 14 that is spaced apart. Further, the first and second lip portions 12 and 15 become thicker as they move away from the pump casing 3. Thereby, the V-shaped pressure receiving part 16 opened to the pump casing 3 side is formed. The rear end surface 17 of the lip seal is perpendicular to the rotating shaft 4.

  The lantern ring 20 interposed between the lip seals 11, 11,... Has an overall ring shape as shown in FIGS. A ring-shaped concave groove 21 is formed on the outer peripheral portion. A plurality of through-holes 22 (22) are opened from the concave groove 21 toward the central portion at a predetermined interval. Therefore, when the shaft seal water is supplied to the concave groove 21, the shaft seal water is uniformly supplied to the outer surface of the shaft sleeve 5 through the plurality of through holes 22 (22). A backup portion 23 having a shape corresponding to the tapered portion 14 of the first lip portion 12 is formed on the pump casing 3 side from the center portion of the lantern ring 20 configured in this manner. Although the inclination angle θ of the backup portion 23 depends on the angle of the taper portion 14 of the first lip portion 12, for example, it is about 25 degrees and R of the tip portion is about 0.4.

  The lip seals 11, 11,... And the lantern rings 20, 20,... Configured as described above are alternately mounted between the lip seal receiver 24 and the seal presser 25 as shown in FIG. Is done. And the shaft seal water supply pipes A, B, and C are connected to the respective concave grooves 21 of the lantern rings 20, 20,. The shaft seal water supply pipes A, B, and C are connected to the respective supply pipes of the shaft seal water supply unit 30. The shaft seal water supply unit 30 includes a shaft seal water tank 31, a pump 32 that boosts the shaft seal water in the tank to an internal pressure of the pump casing 3, a pressure gauge 33, and flow rate adjustment valves 34 and 34 that adjust the respective flow rates. , ..., flow meters 35, 35, ..., check valves 36, 36, ..., etc.

  Further, according to the present embodiment, the sealing means, for example, the 0 ring 25 e is provided between the seal retainer 25 and the shaft sleeve 5. Further, grease or lubricating oil is separately supplied to the lantern ring 20e adjacent to the seal push 25 through the conduit 29.

  Next, the operation of the above embodiment will be described. The pump 32 of the shaft seal water supply unit 30 is activated, and shaft seal water higher than the pressure in the pump casing 3 is supplied through the flow rate adjusting valves 34, 34,. . The rotary shaft 4 is rotationally driven by, for example, an electric motor. Then, as is conventionally known, the slurry is sucked from the suction port 7 and is pumped from the discharge port 9 to a predetermined location. When pumping in this way, the slurry containing solid matter in the pump casing 3 is pressurized and leaks from the shaft seal device 10 to the outside, but the pressure to leak is applied to the pressure receiving portion 16 of the lip seal 11. The tip portion 13 of the first lip portion 12 acts and cooperates with the shaft sleeve to provide a check valve. This prevents leakage. Since a plurality of lip seals 11, 11,... Are provided, they are reliably prevented. At this time, shaft seal water having a pressure higher than the pressure in the pump casing 3 is supplied to the lantern rings 20, 20,..., So that the shaft seal water is the inner peripheral surface of the lantern ring 20 and the outer periphery of the shaft sleeve 5. It flows through the gap with the surface to the lip seal 11, particularly toward the tapered portion 14. This shaft seal water tends to flow toward the pump casing 3 by pushing the first lip portion 12 of the lip seal 11 open. As a result, leakage of the slurry is prevented, the solid matter is prevented from entering, and the solid matter that has entered is washed away. Furthermore, the first lip portion 12 of the lip seal 11 is also cooled. Further, grease or lubricating oil is supplied to the lantern ring 20e on the seal retainer 25 side, and the 0 ring 25e as a sealing means is provided inside the seal retainer 25. It does not leak outside and the sealing effect is not impaired.

  Further, the first lip portion 12 tends to spread or deform due to the pressure of the slurry acting on the lip seal 20, but the lantern rings 20, 20,. Since the backup portion 23 having a shape corresponding to the taper portion 14 is formed, such deformation is prevented.

  It is clear that the present invention is not limited to the above embodiment. For example, it is apparent that the number of lip seals and lantern rings can be increased or decreased without being limited to the above embodiment. Moreover, the pressure of the shaft seal water supplied to a plurality of lantern rings can be individually changed. Further, the pressure in the shaft casing and the pressure of the shaft seal water are always compared, and the pressure of the shaft seal water can be constantly increased.

表１より、耐用時間すなわち掘削距離は、８倍以上に伸びていることが理解できる。 Example: In a tunnel excavation by a muddy water shield method using a slurry pump manufactured by Taiyo Kiko Co., Ltd., the conventional shaft seal device shown in FIG. 3 and the book shown in FIGS. A comparative test of the service life of the inventive shaft seal device was conducted. The results are shown in Table 1.
Since the service life is difficult to grasp under various conditions, the “service life” in Table 1 was evaluated by “digging distance”.
Table 1

From Table 1, it can be understood that the service life, that is, the excavation distance is increased by 8 times or more.

It is sectional drawing which shows a part of slurry pump concerning embodiment of this invention. It is an enlarged view of the principal part concerning embodiment of this invention, The (a) is an expanded sectional view of one lip seal and a lantern ring, The (b) is a partial expanded sectional view of a lantern ring. It is sectional drawing which shows the shaft seal apparatus of the conventional slurry pump.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Slurry pump 2 Impeller 3 Pump casing 4 Rotating shaft 5 Shaft sleeve 10 Shaft seal device
11 Lip seal 12 First lip
13 Tip portion of first lip portion 14 Taper portion
16 Pressure receiving part 20 Lantern ring
23 Backup unit 28 Staffin box
30 shaft seal water supply unit

Claims (2)

The rotary shaft of the slurry pump comprising an impeller and a pump casing, and when the rotary shaft to which the impeller is attached is driven to rotate, the slurry sucked from the suction port is pumped from the discharge port. Is a shaft seal device of a portion passing through the pump casing,
The shaft seal device comprises a plurality of lip seals and a plurality of lantern rings provided between an outer peripheral surface of a shaft sleeve mounted on the rotating shaft and an inner peripheral surface of the staffin box,
The lip seal has a first lip portion whose inner peripheral surface is dynamically in contact with the outer peripheral surface of the shaft sleeve, and its outer peripheral surface is in static contact with the inner peripheral surface of the staffin box. From the second lip portion, the first and second lip portions are formed with a pressure receiving portion that opens in a substantially V shape on the pump casing side, and the first lip portion has the dynamic lip portion. Are integrally formed so as to have a taper portion whose diameter increases rearward from the portion in contact with
And these lip seals are sequentially mounted so that the pressure receiving part faces the pump casing side, and the lantern ring is arranged behind these lip seals,
Grease or lubricating oil is supplied to the lantern ring that is disposed farthest from the pump casing and is pressed by a seal presser having a sealing means, and the other lantern ring is supplied with pressure from the pump casing. A shaft seal device for a slurry pump, characterized in that high shaft seal water is supplied.   The shaft seal device according to claim 1, wherein a backup portion having a shape corresponding to a taper portion of the first lip portion of the lip seal is formed in front of the lantern ring.

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