Pump

Abstract

To provide a pump in which even if a minute foreign body is contained in pumped water, the foreign body is restrained from entering a sliding part of a shaft seal without providing an external mechanism.SOLUTION: A pump 1 according to the present invention comprises a shaft seal 6 through which a main shaft 2 penetrates to the outside of a casing 5. The shaft seal 6 comprises: a suction port 65 for sucking pumped water; a shaft seal body 61 provided with a seal part 63, 69, or 70; a rotating body 64 attached to the main shaft 2; a drain port 66 for draining the pumped water; a discharge port 67 for discharging the pumped water to the seal part 63; and a radial passage 643 provided in the rotating body 64, and passing the pumped water by establishing communication between the suction port 65 and the drain port 66. The drain port 66 is arranged at a position separated from the main shaft 2 with respect to the suction port 65.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a pump equipped with a shaft seal. [Background technology]

[0002] A vertical shaft pump, which has a main shaft extending vertically, is known as a type of pump used to pump fluid. In a vertical shaft pump, an impeller attached to the lower end of the main shaft is driven to rotate by a power source such as a motor, thereby pumping fluid. The main shaft of a vertical shaft pump is rotatably supported relative to a casing by bearings and penetrates the outside of the casing via a shaft seal.

[0003] In such bearings and shaft seals, fluids such as water are used to cool the sliding parts and to prevent wear and seizure. For example, Patent Document 1 describes a vertical pump that uses part of the pumped water to lubricate the bearings, and shows a lubrication system that is used in this vertical pump and can protect the bearings from fine foreign matter contained in the pumped water (see abstract). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-186261 A Summary of the Invention [Problem to be solved by the invention]

[0005] The lubrication system in Patent Document 1 is an external mechanism for a vertical pump. By reducing the amount of equipment required for the external mechanism, the work time and costs involved in manufacturing, operating, and maintaining the external mechanism can be reduced, and the risk of leakage from the external mechanism can be reduced.

[0006] In particular, pumps installed in oceans or rivers have a problem in that the pumped water contains fine foreign matter such as sand, and if the foreign matter accumulates on the sliding part of the shaft seal, the pumped water may not be able to cool the heat generated in the sliding part. Insufficient cooling can cause the shaft seal to seize or increase the vibration of the main shaft, which can cause the pump to become inoperable.

[0007] An object of the present invention is to provide a pump that prevents foreign matter from entering the sliding portion of the shaft seal without requiring an external mechanism, even when the pumped water contains fine foreign matter. [Means for solving the problem]

[0008] In order to achieve the above object, the pump of the present invention comprises: In a pump equipped with a shaft seal in which the main shaft penetrates to the outside of the casing, the shaft seal includes an inlet port for sucking in the pumped water, a seal body provided with a seal portion, a rotor attached to the main shaft, an outlet port for discharging the pumped water, an outlet port for discharging the pumped water to the seal portion, and a radial passage provided in the rotor that connects the inlet port and the outlet port and allows the pumped water to flow; The outlet is located at a position away from the main shaft relative to the inlet. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a pump that prevents foreign matter from entering the sliding portion of the shaft seal without requiring an external mechanism, even when the pumped water contains fine foreign matter. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of a vertical shaft pump having a shaft seal according to an embodiment of the present invention. [Figure 2] 1 is a cross-sectional view of a shaft seal having a gland packing according to a first embodiment of the present invention. [Figure 3]3 is a view of the rotating body 10 taken along the line AA in FIG. 2. [Figure 4] FIG. 6 is a cross-sectional view of a shaft seal having an annular gap according to a second embodiment of the present invention. [Figure 5] FIG. 10 is a cross-sectional view of a shaft seal having a mechanical seal according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments described below. Furthermore, although the following embodiments are vertical shaft pumps, the present invention is also applicable to horizontal shaft pumps with a main shaft extending horizontally. A "vertical shaft pump" may be simply referred to as a "pump." Furthermore, a "shaft seal" is a device that improves watertightness between the rotating and non-rotating parts, and may also be called a "shaft seal device." The direction along the main shaft of the pump is called the "axial direction."

[0012] [Example 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a vertical shaft pump having a shaft seal according to one embodiment of the present invention. In a vertical pump 1, an impeller 3 attached to the lower end of a main shaft 2 extending vertically is rotated by a power source (not shown) such as a motor to pump up a fluid. The main shaft 2 of the vertical pump 1 is rotatably supported relative to a casing 5 by a bearing 4 and penetrates to the outside of the casing 5 via a shaft seal 6. The fluid is sucked in through a pump suction port 7 and led to a pump discharge port 9 by a lifting pipe 8.

[0013] The pumped water delivered through the lift pipe 8 contains fine foreign matter such as sand. Because the pressure of the pumped water increases as the impeller 3 rotates, some of the pumped water leaks out of the casing 5 through the shaft seal 6 due to the pressure difference with the atmospheric pressure outside the casing 5. The greater the amount of leakage from the shaft seal 6, the less pumped water is delivered to the pump discharge port 9, resulting in greater losses in the pump 1. To prevent this, the shaft seal 6 is equipped with a sliding part that causes pressure loss. However, the pumped water leaking from the shaft seal 6 cools the sliding part. If foreign matter accumulates on the sliding part, the pumped water may not be able to cool the sliding part enough to compensate for the heat generated by the sliding part. Furthermore, if foreign matter contained in the pumped water leaking from the shaft seal 6 accumulates in the drain outlet outside the pump, the wastewater may not flow out of the drain outlet and may overflow around the pump 1.

[0014] The shaft seal 6 according to this embodiment will be described in detail with reference to Fig. 2. Fig. 2 is a cross-sectional view of the shaft seal 6 having the gland packing 17 according to the first embodiment of the present invention. Fig. 2 shows an enlarged view of the shaft seal 6 in Fig. 1. The body (seal body) 61 of the shaft seal 6 is formed by the casing 5 (see FIG. 1 ) and has a through-hole 62 in the radial center that penetrates the shaft seal body 61 in the axial direction. The through-hole 62 penetrates the shaft seal body 61 from the lower end surface 61a to the upper end surface 61b, and the main shaft 2 is inserted through the through-hole 62. The through-hole 62 is formed by a conical surface (tapered surface) 62a and a stepped cylindrical surface 62b. The conical surface 62a is positioned below the cylindrical surface 62b. The stepped cylindrical surface 62b is formed by a lower cylindrical surface 62b1 disposed below and an upper cylindrical surface 62b2 disposed above. Therefore, the through-hole 62 is formed by the respective hole portions arranged in this order from the bottom: the conical surface 62a, the lower cylindrical surface 62b1, and the upper cylindrical surface 62b2.

[0015] The conical surface 62a is formed as the inner surface of the shaft seal body 61, and its diameter increases downward, opens to the lower end surface 61a of the shaft seal body 61, and decreases in diameter from bottom to top. A lower cylindrical surface 62b1 is connected to the upper end of the conical surface 62a, and an upper cylindrical surface 62b2 is connected to the upper end of the lower cylindrical surface 62b1.

[0016] The radius of upper cylindrical surface 62b2 is larger than the radius of lower cylindrical surface 62b1, and gland packing 63 is disposed on upper cylindrical surface 62b2. Gland packing 63 forms a seal, and the outer peripheral surface of main shaft 2 slides against its inner peripheral surface. Lower cylindrical surface 62b1 forms discharge port 67 between itself and the outer peripheral surface of main shaft 2, through which a portion of the pumped water is discharged, and supplies a portion of the pumped water to gland packing 63. Rotating body 64, which rotates together with (integrally with) spindle 2, is attached to spindle 2. Rotating body 64 has recessed portion 641, conical surface (tapered surface) 642, and passage 643. Recessed portion 641 forms an upwardly recessed portion on lower end surface 64a of rotating body 64. Conical surface 642 constitutes a part of the outer circumferential surface of rotating body 10, and its diameter decreases upward. Passage 643 extends in the radial direction of spindle 2 and is provided between recessed portion 641 and outer circumferential surface 644 below conical surface 642. For this reason, passage 643 can be called a "radial passage." Suction port 65 is defined between the side wall of recessed portion 641 and the outer circumferential surface of spindle 2.

[0017] The rotor 64 is inserted into the through-hole 62 (hole formed by the conical surface 642) of the seal body 61 so that the conical surface 642 faces the conical surface 62a of the seal body 61. When the rotor 64 and the seal body 61 are combined, an outlet 66 is formed between an outer peripheral surface 645 connected to the lower end surface 64a of the rotor 64 and the lower end of the hole formed by the conical surface 62a of the seal body 61, and a chamber 68 is formed between the conical surface 62a and the conical surface 642 (including the outer peripheral surface 644) of the rotor 64. The passage 643 is provided to communicate the chamber 68 with the suction port 65. The passage 643 is disposed below the outlet 66, and the discharge port 67 is disposed above the chamber 68.

[0018] Rotating body 64 rotates together with main shaft 2, and passage 643 provided in rotating body 64 also rotates. As passage 643 rotates, centrifugal force is generated in the pumped water in passage 643. The pumped water generated by centrifugal force flows radially outward from main shaft 2, and the pumped water containing foreign matter is sucked in through suction port 65.

[0019] The shape of the passage 11 will now be described with reference to Fig. 3. Fig. 3 is a view of the rotor 10 taken along the line AA in Fig. 2. The number of passages 643 provided in the radial direction of the main shaft 2 is plural. Although the number of passages 643 in Fig. 3 is eight, the number is not limited to eight. Furthermore, the shape of the passages 643 does not have to be linear in the radial direction, as long as it has a shape that generates centrifugal force so that the pumped water flows radially outward through the passages 643. Furthermore, the passages (radial passages) 643 may not only be provided extending in the radial direction perpendicular to the axial direction, but also have an inlet and an outlet that are offset from each other in the axial direction.

[0020] The pumped water flowing through passage 643 in the radial direction of the main shaft 2 slows down in chamber 68 located between rotor 64 and seal body 61. Here, a stronger centrifugal force acts on foreign matter such as sand, which has a higher density than the pumped water. Therefore, foreign matter that is subjected to a stronger centrifugal force in chamber 68 flows faster in the radial direction of the main shaft 2 than the pumped water. The foreign matter flowing in the radial direction of the main shaft 2 collides with conical surface 62a of seal body 61. Because the inner diameter of conical surface 62a of seal body 61 relative to the main shaft 2 increases as it approaches outlet 66, the foreign matter that collides with conical surface 62a flows along conical surface 62a and is discharged from outlet 66 into the flow path of pump 1 together with the pumped water.

[0021] As foreign matter is discharged from the discharge port 66, the amount of foreign matter contained in the pumped water is reduced compared to the amount of pumped water sucked in from the suction port 65, and the pumped water is discharged from the discharge port 67 and flows into the sliding part, the gland packing 63.

[0022] According to this embodiment, even if the pumped water contains minute foreign matter, the foreign matter is prevented from entering the sliding portion (gland packing 63) of the shaft seal 6 without providing an external mechanism to the pump 1. This reduces the work time and costs involved in manufacturing, operating, and maintaining the external mechanism, and also reduces the risk of pumped water leaking from the external mechanism.

[0023] In this embodiment, as shown in Fig. 2, the shape of the hole 62a located at the bottom of the through-hole 62 of the shaft seal body 61 is a conical surface, but is not limited to a conical surface. The hole 62a may have any shape as long as the inner diameter thereof increases toward the discharge port 66. For example, the hole 62a may have a shape with corners or a hemispherical shape.

[0024] [Example 2] FIG. 4 is a cross-sectional view of a shaft seal 6 having an annular gap 69 according to a second embodiment of the present invention. In the first embodiment, as shown in FIG. 2, the component (sealing portion) present on the exterior side of the shaft seal body 61 is the gland packing 63, but it is not limited to the gland packing 63. It may be any component that suppresses leakage of pumped water to the exterior of the casing 5. For example, it may be an annular gap 69 between the main shaft 2 and the shaft seal body 61, as shown in FIG. 4. The other configurations are the same as those in the first embodiment.

[0025] [Example 3] FIG. 5 is a cross-sectional view of a shaft seal 6 having a mechanical seal 70 according to a third embodiment of the present invention. The component (sealing portion) that prevents the pumped water from leaking to the outside of the casing 5 may be, for example, a mechanical seal 70 shown in Fig. 5. The other configurations are the same as those in the first embodiment.

[0026] The pump 1 according to the present invention described above has the following features. (1) In a pump 1 having a shaft seal 6 in which a main shaft 2 penetrates to the outside of a casing 5, The shaft seal 6 includes an inlet 65 for sucking in the pumped water, a seal body 61 provided with seal portions 63, 69, and 70, a rotor 64 attached to the main shaft 2, an outlet 66 for discharging the pumped water, an outlet 67 for discharging the pumped water to the seal portions 63, 69, and 70, and a radial passage 643 provided in the rotor 64 and communicating between the inlet 65 and the outlet 66 to allow the pumped water to flow, the outlet 66 being located away from the main shaft 2 with respect to the inlet 65. As a result, centrifugal force is generated in the pumped water in the radial passage 643.

[0027] (2) The radial passage 643 is provided in the radial direction of the main shaft 2, and is provided so that centrifugal force is generated in the pumped water in the radial passage 643 when the rotor 64 rotates.

[0028] (3) The radial passage 643 causes the pumped water drawn in from the suction port 65 to flow radially outward from the main shaft 2 by centrifugal force.

[0029] (4) The shaft seal body 61 has an inner surface 62a whose diameter increases downward. The discharge port 66 is disposed below the radial passage 643, The inner surface 62 a directs the pumped water that flows out of the radial passage 643 due to centrifugal force toward the discharge port 66 .

[0030] (5) The discharge port 66 discharges the pumped water containing the foreign matter guided by the inner surface 62 a into the flow path of the pump 1 .

[0031] (6) A chamber 68 is formed between the inner surface 62a of the shaft sealing body 6 and the rotor 64. The chamber 68 discharges foreign matter having a density greater than that of the pumped water from the discharge port 66 by centrifugal force.

[0032] (7) The discharge port 67 sends the pumped water, which contains less foreign matter than the pumped water drawn in from the suction port 66, to the seal portions 63, 69, and 70.

[0033] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations. [Explanation of symbols]

[0034] 2...main shaft, 5...casing, 6...shaft seal, 1...pump, 62a...inner surface of shaft seal body 61, 65...suction port, 63, 69, 70 seal portion, 61...shaft seal body, 64...rotating body, 66...discharge port, 67...discharge port, 68...chamber, 643...radial passage.

Claims

1. In a pump equipped with a shaft seal in which the main shaft penetrates to the outside of the casing, the shaft seal includes an inlet port for sucking in the pumped water, a seal body provided with a seal portion, a rotor attached to the main shaft, an outlet port for discharging the pumped water, an outlet port for discharging the pumped water to the seal portion, and a radial passage provided in the rotor that connects the inlet port and the outlet port and allows the pumped water to flow; The pump is characterized in that the discharge port is disposed at a position away from the main shaft relative to the suction port.

2. 2. The pump of claim 1, The radial passage is provided in the radial direction of the main shaft, and is configured so that centrifugal force is generated in the pumped water in the radial passage when the rotating body rotates.

3. 3. The pump according to claim 2, The radial passage causes the pumped water drawn in through the suction port to flow radially outward from the main shaft by centrifugal force.

4. 3. The pump according to claim 2, The shaft seal body has an inner surface whose diameter increases downward, The discharge port is disposed below the radial passage, The pump is characterized in that the inner surface allows pumped water that flows out of the radial passage due to centrifugal force to flow toward the discharge port.

5. 5. The pump according to claim 4, The discharge port discharges the pumped water containing foreign matter guided by the inner surface into a flow path of the pump.

6. 5. The pump according to claim 4, a chamber formed between the inner surface of the shaft sealing body and the rotating body, The pump is characterized in that the chamber discharges foreign matter having a density greater than that of the pumped water from the discharge port by centrifugal force.

7. 7. The pump of claim 6, The pump is characterized in that the discharge port sends pumped water containing less foreign matter than the pumped water sucked from the suction port to the seal portion.

Images