JP4859607B2 - Sealing device for large shaft pump - Google Patents

Description

  The present invention relates to a sealing device for a large shaft pump.

It is necessary to discharge a large amount of water that contains a lot of earth and sand in order to discharge a large amount of water in response to flood damage, etc., and large shaft pumps are actively developed, with shaft diameters of 300 to It has come to reach 600mm.
Such a drainage pump is provided in a pump suction chamber, and a propeller is installed in the pump casing, and the propeller shaft projects outside the pump casing and is connected to a motor for driving. In such a configuration, a sealing device for sealing between the propeller shaft and the pump casing is essential.

Japanese Utility Model Publication 2-94398 JP 2006-214409 A JP 2004-108169 A

However, as the shaft diameter of the propeller shaft becomes larger, various problems have occurred with the sealing device, and the conventional configuration cannot cope with it.
For example, in the case of a gland packing that has been widely used in the past, a large shaft diameter increases the bearing clearance and the shaft runout. .
In the case of a mechanical seal, there are problems such as clogging due to slurry such as earth and sand as well as replacement when the shaft diameter increases. In addition, this type of pump sometimes has a dry operation, and there is a problem that countermeasures in this case are necessary.
The object of the present invention is to solve the problems of the prior art.

In order to achieve the above object, the large shaft pump seal device provided in the pump suction chamber of the present invention is formed around the shaft shaft of the pump in the large shaft pump seal device provided in the pump suction chamber. In the first to third seal chambers, the segment seal provided in the lowermost first seal chamber in the seal chamber, and the second seal chamber above the first seal chamber, the shaft is attached to a seal chamber flinger (Flinger) which rotates together with Tatejiku, the second communication with the seal chamber, the discharge hole and said to discharge to the pump suction chamber gravel or the like of the second seal chamber by rotation of said flinger A pipe communicating with the pump suction chamber, a valve provided in the middle of the pipe, a segment seal provided in a third seal chamber above the second seal chamber, and provided on the third seal chamber. Leaking chamber and A pump that communicates with the leak receiving chamber and discharges the fluid that has flowed into the leak receiving chamber to the outside of the seal device; and a pump that is mounted on the shaft and is rotated together with the shaft at a lower side of the first seal chamber. possess the chamber flinger (Flinger), and by adjusting the pressure by opening the valve to adjust the pressure of the second and third seal chamber, control the outflow of the fluid into the leakage receiving chamber It is possible .
In the above configuration, since the bottom pump chamber flinger prevents intrusion of earth and sand, and the sand that has entered through the middle seal chamber flinger and the discharge hole can be discharged, the amount of earth and sand is reduced to the third seal chamber. This reduces clogging and sliding surface wear and stabilizes the sealing performance. Further, the pressure is reduced by returning from the second seal chamber to the suction side (pump suction chamber), the pressure in the third seal chamber is lowered, and the outflow to the atmosphere side is reduced. Returning from the second seal chamber to the pump suction chamber results in a leakage loss, but it does not affect the overall flow rate, and seal performance can be ensured.
As described above, by providing a plurality of seal chambers and leakage receiving chambers, the sealing performance is improved, and by using a segment seal, seal replacement is facilitated.

  According to the sealing device for a large shaft pump of the present invention, there is an effect that there is no clogging of earth and sand, high sealing performance can be maintained, and maintenance such as seal replacement is easy.

Embodiments of the present invention will be described below with reference to the drawings.
First, the configuration of the pump P will be described with reference to FIG.
The pump P installed in the pump suction chamber is provided with an impeller 92 in a pump casing 93. The impeller 92 performs a pumping action so that water is drawn from below and discharged from above. The shaft 91 penetrates the pump casing 93 and is connected to the motor 90 so as to receive the rotational force. 94 is a bearing.
A seal device A that seals between the shaft 91 and the pump casing 93 is provided at a portion where the shaft 91 passes through the pump casing 93.

The configuration of the sealing device A is shown in FIG. FIG. 1 is a half sectional view.
A casing 50 is fitted around the shaft 91 with a predetermined gap from the shaft 91, and the first seal chamber 1, the second seal chamber 2, the third seal chamber 3, and the leakage are sequentially provided from the bottom by the casing 50. A receiving chamber 4 is formed.
A pump chamber flinger 5 is further mounted below the first seal chamber 1.

A segment seal 10 is provided in the first seal chamber 1. The segment seal 10 has two segment rings 15, 15, and an inner peripheral surface of the segment ring 15 forms a seal surface S 10 that slides in contact with the shaft 91. Further, the end surface of the upper segment ring 15 contacts the seal chamber upper end surface 11 of the first seal chamber 1 to form the seal surface S11, and the end surfaces of the segment rings 15 and 15 contact to form the seal surface S12. Yes. Sealing is performed by these sealing surfaces.
The segment seal 10 is provided with a spring 16 that presses the segment ring 15 against the upper end surface 11 of the seal chamber. A plurality of springs 16 are arranged in the circumferential direction of the segment seal 10, and a part thereof is housed in a spring hole 17 formed in the lower segment ring 15. Thereby, the clogging by the solid content of the spring 16 can be prevented.
As another sealing method, it is also possible to limit the outflow amount with a floating bush 19 as shown in FIG.

A seal chamber flinger 20 is installed in the second seal chamber 2. The seal chamber flinger 20 is divided into two parts, is fixed to the shaft 91 by a bolt, rotates together with the shaft 91, and has a function of discharging solid content in the radial direction by the centrifugal force. A discharge hole 25 is provided in the radial direction in the seal chamber peripheral surface 21 of the second seal chamber 2, and the discharge hole 25 passes through the casing 50 and is connected to the pump suction chamber by a predetermined pipe (not shown). Communicate. A valve is provided in the middle, and the pressure is adjusted according to the opening, and the pressure in the third seal chamber 3 is adjusted to control the amount of outflow to the leak receiving chamber 4 .
With the above configuration, solid content such as earth and sand in the second seal chamber 2 is discharged to the outside. In addition, the pressure in the seal chamber 2 can be adjusted.
In this embodiment, the upper surface of the seal chamber flinger 20 is a tapered surface 26, which enhances the solid content discharge effect.

Similar to the first seal chamber 1, a segment seal 30 is provided in the third seal chamber 3. The segment seal 30 has two segment rings 35, 35, and the inner peripheral surface of the segment ring 35 forms a seal surface S 30 that slides in contact with the shaft 91. Further, the end surface of the upper segment ring 35 is in contact with the seal chamber upper end surface 31 of the third seal chamber 3 to form the seal surface S31, and is operated in the radial direction with respect to the shaft runout. The end faces of the segment rings 35, 35 are in contact with each other to form a seal surface S32. Sealing is performed by these sealing surfaces.
The segment seal 30 is provided with a spring 36 and presses the segment ring 35 against the upper end surface 31 of the seal chamber. A plurality of springs 36 are arranged in the circumferential direction of the segment seal 30, and a part thereof is accommodated in a spring hole 37 formed in the lower segment ring 35. Thereby, the clogging by the solid content of the spring 36 can be prevented.

A discharge hole 45 is provided in the inner peripheral surface 41 of the leak receiving chamber 4 formed on the third seal chamber 3, and the discharge hole 45 passes through the casing 50 and has a predetermined pipe (not shown). Communicated with the pump suction chamber.
With the above configuration, the fluid that has flowed out into the leak receiving chamber 4 is returned to the pump suction chamber, so that there is no fluid flowing out in the shaft seal device A, and a good state can be maintained.

  A flinger 5 is further provided below the first seal chamber 1. The flinger 5 is installed at a predetermined distance from the lower end of the casing 50. The flinger 5 is fixed to a shaft 91 and rotates together with the shaft 91 so as to prevent the solid content such as earth and sand from entering the sealing device A by centrifugal force.

In the above configuration, the water and solid content pumped up by the rotation of the impeller 92 are discharged from the pump casing 93. At that time, the space between the pump casing 93 and the shaft 91 is effectively sealed by the sealing device A.
In the sealing device A, the solid content is first removed by the rotation of the pump chamber flinger 5. Further, sealing is performed in the first seal chamber 1, and solid content is discharged from the discharge hole 25 in the second seal chamber 2. Further, the fluid sealed in the third seal chamber 3 and further leaked in the leak receiving chamber 4 is discharged from the discharge hole 45 to the suction chamber.
With the above configuration, sealing is effectively performed, and clogging due to solid content does not occur. It can also be used in a dry state and has good tracking performance against shaft runout.
Further, since the segment seals 10 and 30 are composed of a plurality of segment pieces, there is an effect that it is not necessary to disassemble the bearing 94 at the time of replacement.

1 is a schematic half sectional view showing an embodiment of the present invention. Explanatory drawing which shows operation | movement of one Embodiment of this invention. Schematic which shows other embodiment of this invention.

Explanation of symbols

1: first seal chamber, 2: second seal chamber, 3: third seal chamber, 4: leak receiving chamber, 5: pump chamber flinger, 10: segment seal, 11: upper end surface of seal chamber, 15: segment ring, 16: Spring, 17: Spring hole, 19: Floating bush, 20: Seal chamber flinger, 21: Seal chamber peripheral surface, 25: Discharge hole, 26: Tapered surface, 30: Segment seal, 31: Upper end surface of seal chamber, 35 : Segment ring, 36: spring, 37: spring hole, 41: inner peripheral surface, 45: discharge hole, 90: motor, 91: shaft, 92: impeller, 93: pump casing, 94: bearing.

Claims (1)

In the seal device for large shaft pumps provided in the pump suction chamber,
First to third seal chambers formed around the shaft of the pump;
A segment seal provided in a lowermost first seal chamber in the seal chamber;
In the second seal chamber above the first seal chamber, a seal chamber flinger attached to the shaft and rotating together with the shaft;
Provided in the middle of the pipe communicated with the second seal chamber, a discharge hole for discharging earth and sand in the second seal chamber to the pump suction chamber by the rotation of the flinger, a pipe communicating with the pump suction chamber A valve,
A segment seal provided in a third seal chamber above the second seal chamber;
A leak receiving chamber provided on the third seal chamber;
A discharge hole communicating with the leak receiving chamber and discharging the fluid flowing into the leak receiving chamber out of the sealing device;
In the lower side of the first seal chamber, said mounted on vertical axis, have a, a pump chamber flinger which rotates with Tatejiku,
By adjusting the pressure according to the opening of the valve, the pressure of the second and third seal chambers can be adjusted, and the amount of fluid flowing into the leak receiving chamber can be controlled.
A sealing device for a large shaft pump characterized by that.

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