JPS6014958Y2 - Shaft sealing device for large vertical pumps - Google Patents

Description

[Detailed description of the invention] This invention relates to a shaft sealing device for a large chamber shaft pump.

As shown in FIG. 1, a conventional large chamber shaft pump has a water conduit 2 extending tangentially from a part of the circumference, and a pump casing 3 formed at the open center side.
A sheet metal casing form 1 having a circular cross section in the radial direction and a spiral annular shape is provided, and a concrete 4 is placed around the outer circumference of the form 1.
Using a concrete casing that has been cast and hardened, a casing cover 5 is placed above the center side of the formwork, and a casing liner 8 is placed below.
The lower part of the support shaft 9 supported by the bearing device 6 is connected to the shaft sealing device 7.
The shaft is sealed and protruded into the pump casing 3, and an impeller 10 provided at the end of the protruding shaft is configured to face the casing liner 8 with a small gap, and the rotation of the impeller 10 causes the flow to flow from the suction port 11. The water sucked in through the channel 12 is discharged into the casing formwork 1 by centrifugal action, and is sent to the outside through the water conduit 2.

Therefore, in this type of large chamber shaft pump, especially in a large chamber shaft pump with a closed channel, water pressure is constantly applied to the shaft seal even when the water level on the suction side is high, W or L, that is, the low water level. In this state, in order to replace the gland backing of the shaft seal or other shaft seal members, this water pressure must be removed, in other words, the water level on the suction side must be lowered to a level below the shaft seal. It is necessary to do so.

Therefore, conventionally, the water level on the suction side is controlled by the shaft sealing part 7.
In order to reduce the flow to the following level, the suction flow path A communicating with the suction port 11 of the pump is shut off from the fluid supply side with an opening/closing gate or a cut-off gate B as shown in FIG. The required amount of fluid in channel A was removed.

However, providing the above-mentioned opening/closing gate was extremely irrational and wasteful because the construction cost would be significantly high and it would not be used all the time.

In this respect, the corner drop gate B can be constructed at a lower cost than the case where an opening/closing gate is provided, even considering its structure.

Therefore, in general, for economic reasons,
The current situation is that simple cut-off gates are installed instead of using large-scale blocking means such as opening/closing gates (
Japan Industrial Machinery Manufacturers Association, Industrial Machinery No. 341,
(Refer to February issue of Showa 5 Group).

However, in the case of using this corner drop gate B, it is necessary to sequentially insert a number of square timbers b between the guides C and c using a winch or the like to block the suction flow path A, and then pull up each square timber again. However, there is a problem in that the work becomes extremely troublesome.

This idea solves these conventional problems,
Even if the water level in the suction flow path is higher than the position of the shaft seal portion, the shaft seal member of the shaft seal portion can be easily replaced without providing a means for blocking the suction flow path such as a corner drop gate. , provides a shaft sealing device for a large chamber shaft pump.

That is, the shaft sealing device for a large chamber shaft pump of the present invention has a structure in which the shaft is sealed from the pump chamber, and includes a device main body that is provided with a shaft sealing member that is in constant sliding contact with the circumferential surface of the shaft. A concave groove is provided around the inner circumferential surface of the device main body on the pump casing side side of the shaft sealing member, and a ring made of an elastic body is provided in the concave groove and faces the shaft circumferential surface of the support shaft at a distance. A shaped hollow tube is fitted therein, and by introducing fluid pressure into the hollow tube, the inner surface of the tube can be pressure-sealed to the circumferential surface of the shaft.

Therefore, with such a configuration of the present invention, when replacing the shaft sealing member, it is sufficient to first introduce fluid pressure into the ring-shaped hollow tube.

Then, the side of the hollow tube that is not restrained by the groove, that is, the side of the circumferential surface of the support shaft, bulges out, and the inner surface of the hollow tube comes into pressure contact with the circumferential surface of the shaft, thereby causing the shaft sealing member and the pump casing to bulge out. It is possible to insulate the water pressure applied to this shaft sealing member by sealing the space between the two shafts.

Then, by removing the retainer of the shaft seal member, etc., the shaft seal member can be replaced without being affected even if the water level on the suction flow path side is higher than the shaft seal portion.

After replacing the shaft sealing member, by removing the fluid pressure inside the hollow tube again, the bulged hollow tube will contract with its own elasticity and return to its original state, reducing the shaft circumference. It breaks the seal on the surface.

Hereinafter, one embodiment of this invention will be described in detail with reference to FIG. 2.

In this FIG. 2, the same reference numerals as those in FIG.
A shaft sealing member 14, such as a ground backing, which is packed from above into the support shaft 9 and seals the shaft by always slidingly contacting the peripheral surface of the shaft 9, and a backing presser 1 which presses and holds this shaft sealing member 14.
5, which are generally constructed in two parts to facilitate assembly and installation of the pump.

In this embodiment with the above configuration, a groove 16 is provided around the inner circumferential surface of the device main body 13 on the side of the pump casing 3 from the position of the shaft sealing member 14 so as to be perpendicular to the axial direction.
A ring-shaped hollow tube 17 is fitted inside the tube 6.

This hollow tube 17 is made of an elastic body such as rubber, and is large enough to fit tightly into the groove 16 and face the shaft peripheral surface of the corresponding support shaft 9 at a distance. The hollow tube 17 is shaped into a shape and has sufficient elasticity so that it can expand and contract freely, and a communication pipe 18 that communicates with the inside of the hollow tube 17 is taken out to the outside. Fluid pressure can be applied to the inside of the hollow tube 17 from the inside.

Therefore, in this embodiment, when no fluid pressure is applied to the inside of the hollow tube 17, the hollow tube 17 is held in the state shown in the figure (initially shaped), and its inner surface 17a is the corresponding shaft peripheral surface of the support shaft 9. The pump device is located at a position with a predetermined distance between the pump and the pump, and the pump device can operate normally in this state.

When replacing the shaft sealing member 14 in this case, by introducing fluid pressure into the hollow tube 17 from the communication pipe 18, the hollow tube 17 is moved to the side that is not restrained by the groove 16, that is, the side of the support shaft 9. The shaft peripheral surface side bulges, and its inner surface 17a comes into pressure contact with the corresponding shaft peripheral surface, sealing between the shaft sealing member 14 and the pump casing 3, and insulating the water pressure applied to the shaft sealing member 14. do.

In this state, the backing presser 15 can be removed and the shaft seal member 14 can be easily replaced.

After this replacement work is completed, the fluid pressure inside the hollow tube 17 is removed again, and the bulged hollow tube 17 contracts with its own elasticity and returns to its original state.
The seal on the circumferential surface of the shaft is also released.

As detailed above, according to this invention, in a configuration in which the support shaft is sealed from the pump casing, a hollow tube shaped into a certain shape and surrounded by a concave groove is provided between the shaft sealing member and the pump casing. Since the sealing is performed by the pressure applied to the circumferential surface of the chamber shaft due to the expansion of the shaft sealing member, water pressure on the shaft sealing member is insulated, and the shaft sealing member can be replaced very easily.

For this reason, as in the past, it is necessary to install an opening/closing gate that is expensive to construct just to replace the shaft seal member, or to install a corner drop gate that requires a troublesome corner cutting operation, or even to prevent the internal fluid from being cut off. There is no need to perform troublesome work such as draining water, and the shaft seal member can be easily replaced with a very inexpensive device.

In addition, the hollow tube introduces fluid pressure into its interior,
Since the shaft peripheral surface is sealed and released only by discharging, the operation is simple and reliable, there is no risk of water leakage, and it can also withstand a considerable amount of water pressure.

[Brief explanation of drawings]

Figure 1 is a sectional view showing the general configuration of a large chamber shaft pump, Figure 2
The figure is an enlarged sectional view showing the structure of a shaft sealing device to which an embodiment of this invention is applied, and FIG. 3 is a sectional view of the curved portion shown in FIG. 2. 1... Casing formwork, 3... Pump casing, 6... Bearing device, 7...
Shaft sealing device, 8...Casing liner, 9...
...Spindle 1.10...Impeller, 13...
...Device main body, 14...Shaft sealing member, 15...
... Backing presser foot, 16 ... Concave groove, 17.
・Curved hollow tube, 17a...inner surface, 18・
...Communication pipe.

Claims (1)

[Scope of utility model registration request] In a configuration in which the shaft is sealed from the pump chamber, a device main body is provided with a shaft sealing member that is always in sliding contact with the peripheral surface of the shaft, and the inner circumference of the device main body is closer to the pump casing than the shaft sealing member. A concave groove is provided around the surface, and a ring-shaped hollow tube made of an elastic material facing the circumferential surface of the spindle at a distance is fitted into the concave groove, and fluid pressure is applied to the inside of the hollow tube. A shaft sealing device for a large chamber shaft pump, characterized in that the inner surface of the tube can be sealed under pressure to the circumferential surface of the shaft.