JPS6249477B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a liquid leakage prevention device for a centrifugal pump, and more specifically, to a liquid leakage prevention device for a centrifugal pump in which wear of a seal packing for preventing liquid leakage is extremely reduced. This invention relates to a prevention device.

(Prior Art) Conventionally, as shown in Japanese Utility Model Publication No. 51-26326, a motor is fixed to a rotating shaft, rotates together with the rotating shaft, interlocks with the rotation and stop of the rotating shaft, and is connected to the rotating shaft. a moving member that moves along the axis and returns; the movement of the moving member opens and closes a gap in the shaft hole into which the rotating shaft is inserted, and the liquid in the vortex chamber leaks through the gap in the shaft hole; Liquid leakage prevention devices are known that prevent liquid leakage.

(Problems to be Solved by the Invention) However, the conventional liquid leakage prevention device described above has the following problems.

Although the seal packing is attached to the rotating shaft, it is technically difficult to actually attach the seal packing to the rotating shaft.

The moving member (presser body) starts the rotation of the rotating shaft,
Even during low-speed rotation when stopped, the moving body moves away from the seal packing due to the relationship between the operating pin fixed to the rotating shaft and the tapered hole formed in the moving body, preventing wear due to rotational contact of the seal packing. However, leaving the seal packing open during low speed rotation is disadvantageous in terms of leakage prevention.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a liquid leakage prevention device for a centrifugal pump that is highly effective in preventing liquid leakage while extremely reducing wear on the seal packing.

(Means for solving the problem) A liquid leakage prevention device for a centrifugal pump according to the present invention includes:
In order to solve the above problem, the impeller of a centrifugal pump, which feeds liquid in a predetermined direction by rotating an impeller for pumping liquid in a volute chamber, is fixed to a rotating shaft, and the impeller is fixed to the rotating shaft. a shaft hole in which the rotary shaft is inserted by the movement of the movable member, comprising a movable member that rotates together with the rotation and stop of the rotary shaft and moves and returns along the rotary shaft; In a liquid leakage prevention device for a centrifugal pump that prevents liquid in the swirl chamber from leaking through a gap, a portion of the movable member closer to the swirl chamber includes:
moving in the direction of the shaft hole together with the moving member along the rotation axis and returning, and thereby contacting and separating from a seal packing attached to the outer wall of the shaft hole to seal and release the gap in the shaft hole; A rotatable seal ring body is attached to the movable member.

(Function) During low-speed rotation when starting and stopping rotation, the moving body comes into contact with the seal packing via the freely rotatable seal ring body to prevent liquid leakage, but regardless of the subsequent rotation of the moving body, As soon as the seal ring body comes into contact with the seal packing, it stops due to the contact wear, so there is almost no wear on the seal packing due to the presence of the freely rotatable seal ring body, and the effect of preventing liquid leakage is extremely high.

(Embodiment) FIG. 1 shows an embodiment of the present invention, and a centrifugal pump, which is designated as a whole by reference numeral 1 in the figure, is composed of a centrifugal pump body 2 and a motor M that drives the centrifugal pump body 2.

The pump body 2 has an outer shell formed by an upper casing 3 and a lower casing 4, and a rotary shaft 5 is rotatably supported in the center of the pump body 2 on its center line.

The centrifugal pump 1 employs a vertical type in which the rotating shaft 5 is vertically disposed, and the upper end of the rotating shaft 5 is connected to an output shaft (not shown) of a motor M. At the top of the rotating shaft 5, a seal packing 23 (described later) installed in the upper casing 3 is provided.
A liquid leakage prevention device 6 is installed together with the liquid leakage prevention device 6 to prevent liquid leakage. The leakage prevention device 6 is
As shown in Fig. 3, an outer shell is formed by an upper case 7 and a lower case 8 fixed to the rotating shaft 5, and an annular space 9 (see Fig. 3 and ) is formed as shown in Figure 4. A moving member 10 is fitted into the lower part of the lower case 8 so as to be movable in the axial direction of the rotating shaft 5. This moving member 10 is composed of an outer ring 11 and an inner ring 12 integrally screwed thereto. Then, the outer ring 11 and the inner ring 12
A diaphragm-type packing 14 is attached between the fixing ring 13 and the outer peripheral end thereof in a fixed state. On the other hand, the inner circumferential end of this packing 14 is held between the upper end of a bush 15 fitted and fixed to the rotating shaft 5 and the lower case 8, and the inner circumferential end of the packing 14
It is in sliding contact with the circumferential surface of. This packing 14 is
When the pump is stopped, air and liquid are prevented from leaking from the air chamber A, which will be described later. A seal ring body 17 is rotatably attached between the inner ring 12 and the bush 15, and the seal ring body 17, the inner ring 12, the fixed ring 13, and the bush 15 are in smooth sliding contact. Several guide pins 18 are arranged at equal angular intervals in the circumferential direction on the upper part of the moving member 10, and these guide pins 18 pass through the lower case 8 of the liquid leakage prevention device 6. It extends into the space 9. In addition, the upper case 7 and the outer ring 11
A coiled spring 19 is elastically mounted between the upper surface of the guide pin 18 and the guide pin 18 . As a result, the movable member 10 is always given a downward moving force.

Further, a boss 20 that contacts the lower end of the bush 15 and rotates together with the rotary shaft 5 is fitted and fixed to the rotary shaft 5 . A seal ring 21 is interposed between the upper end of the boss 20, the lower end surface of the bush 15, and the inner peripheral surface of the inner ring 17, as shown in FIG.

Furthermore, a partition wall 22 is provided at the center of the upper casing 3, as shown in FIG. A shaft hole 22a into which the rotating shaft 5 with a boss 20 is inserted is provided in the center of the partition wall 22.
A seal packing 23 is fixedly installed on the outer wall portion of the shaft hole 22a by a presser ring 24.

Lip portion 23a of this seal packing 23
(As shown in FIGS. 3 and 5), when the pump is stopped and started, the seal ring body 17
By contacting the lower end surfaces of the two, leakage of air and liquid from the air chamber A (FIG. 1), which will be described later, is prevented.

On the other hand, a space 9 (a third
In FIG. 2, a plurality of guide pins 25 extending radially with respect to the rotating shaft 5 are suspended horizontally. A slider 26 is slidably fitted into these guide pins 25. A flange portion 26a is provided at the inner end of each slider 26, and a groove 26 having a conical slope is provided on the outer surface of the flange portion 26a.
b is formed all around the circumference.

On the other hand, a seal opening/closing pin 27 is slidably fitted on the lower case 8 side parallel to the rotating shaft 5. An inverted truncated conical head 27a is formed at the upper end of the opening/closing pin 27. The inclination angle of the outer peripheral surface of the head 27a is equal to the inclination angle of the groove 26b of the movable element 26, and as the movable element 26 moves, the inclined surface of the groove 26b and the outer peripheral surface of the head 27a slide. come into contact with Further, the lower end 27b of the seal opening/closing pin 27 is fixed to the upper side of the outer ring of the moving member 10. Therefore, the seal opening/closing pin 27
and the moving member 10 move together.

By the way, another partition wall 28 is formed at the lower end of the upper casing 3, and in the center of this partition wall 28 is a shaft hole 28a into which the rotating shaft 5 with the boss 20 is inserted. It is formed.

An air chamber A is formed between this partition wall 28 and the partition wall 22. When the liquid level W on the suction side (shown in FIGS. 5 and 6) becomes higher than the partition wall 28, the air chamber A is opened from the vortex chamber 29 through the shaft hole 28a of the rotating shaft 5. , 22a, and is not particularly necessary when the liquid level W is low.

In addition, the partition wall 28 at the lower end of the upper casing 3
An impeller 30 is fixed to the lower end of the rotating shaft 5 located in the spiral chamber 29 formed between the lower casing 4 and the partition wall 22 when there is no air chamber A. 30 rotates together with the rotating shaft 5. Note that when the air chamber A is not provided, the impeller 30 and the lower casing 4 are arranged directly below the partition wall 22.

The impeller 30 has a plurality of sealing blades 3 arranged radially or spirally on its upper surface side.
1, and a main blade 32 for pumping liquid on the lower surface side.
It is equipped with The upper end of the sealing blade 31 is close to the upper wall surface of the swirl chamber 29.

Although the above embodiments have been described with respect to a vertical pump, a horizontal pump may also be used.

Next, the operation of this embodiment configured as above will be explained.

First, when the motor M rotates, the rotating shaft 5 and the impeller 30 rotate together, and the main blades 32 of the impeller 30 suck liquid from the suction port 33, and the centrifugal force causes the liquid to be drawn from the discharge port 34. Discharge.

On the other hand, as the rotating shaft 5 rotates, the leakage prevention device 6 integrated therewith also rotates. When the rotational speed is low at the moment of starting, the centrifugal force generated in the moving element 26 is small, so the moving member 10 does not move. Therefore,
During this time, the lower end surface of the seal ring body 17 remains in contact with the lip portion 23a of the seal packing 23. However, since the seal ring body 17 has a greater frictional force with the lip portion 23a than other contact portions, the lip portion 23a does not wear out when rotation is prevented. As the rotational speed increases, the slider 26 that is slidably fitted on the guide pin 25 also begins to move outward, causing the slope of the groove 26b of the slider 26 and the head 27a of the seal opening/closing pin 27 to begins to come into sliding contact with the inclined surface. As the mover 26 moves outward, it begins to fit deeply into the groove 26b, and at the same time, the opening/closing pin 27 begins to move upward. This movement is performed against the elastic force of the spring 19, and at the same time the moving member 10 begins to move upward. At the same time, the seal ring body 17 also moves upward,
Until then, the lip part 23 of the seal packing 23
The contact with the seal ring body 17, which had been in contact with a and maintained a sealed state, is released.

In this way, when the seal packing 23 separates from the seal ring body 17, the upper casing 3
Outside air is led from an opening 3a formed on the circumferential surface of the seal ring 17, and into the air chamber A through between the lip portion 23a and the lower end of the seal ring body 17.

On the other hand, during this rotation operation, as shown in FIG. 6, the rotation of the impeller 30 causes the air chamber A to
liquid is removed from the At the same time, the liquid L pressed by the centrifugal force of the sealing blade 31 exists between the sealing blade 31 and the peripheral wall surface and the upper wall surface of the swirl chamber 29, resulting in a so-called liquid seal state. The liquid sucked from the suction port 33 does not flow into the air chamber A.

When the motor M stops, the rotation of the rotating shaft 5 also stops, and the centrifugal force on the mover 26 also disappears, so the seal opening/closing pin 27 and the moving member 10 are automatically pushed back downward by the elastic force of the spring 19. . Accordingly, the lower end surface of the seal ring body 17 is attached to the lip portion 23 of the seal packing 23.
The shaft is again pressed against the shaft a, and as shown in FIG. 5, the shaft is completely sealed.

At this time, all rotating parts are stopped, and the lip portion 23a of the seal packing 23 is not worn out.

Further, at this time, the liquid seal state between the sealing blade 31 and the peripheral wall surface and the upper wall surface of the swirl chamber 29 is also released, so the liquid flowing back from the discharge port 34 also enters the air chamber A. However, since there is air sealed by the seal packing 23 in this air chamber A, the liquid will only enter until the pressure is balanced with the air, and the liquid will not be guided to the seal packing 23. do not have.

Note that during low-speed rotation due to inertia just before stopping, the movable member 10 descends and contacts the lip portion 23a of the seal packing 23 on the lower end of the seal ring body 17. Since the inertial rotation of the seal ring body 17 itself is quickly stopped by the frictional force between the seal ring body 17 and the lip portion 23a, no friction occurs on the lip portion 23a.

(Effect of the invention) It is attached to the rotating shaft, moves and returns in conjunction with the rotation stop of the rotating shaft, and comes into contact with and separates from the seal packing installed on the wall of the shaft hole into which the rotating shaft is inserted, thereby closing the shaft hole gap. A seal ring body that moves together with the movable member and is rotatable relative to the movable member is attached to a movable member that opens and closes and prevents leakage of liquid in the volute chamber, and the seal ring body moves through the seal ring body. Since the member is made to come into contact with and separate from the seal packing, the moving member comes into contact with the seal packing via the seal ring body during low speed rotation during starting and stopping.
Regardless of the subsequent rotation of the moving member, the seal ring body immediately stops rotating due to frictional contact with the seal packing, so even when the shaft is sealed during low-speed rotation due to starting and stopping, the seal packing and rotating parts are Rotating contact can be prevented, and wear on the seal packing is almost eliminated.

In this way, the liquid leakage prevention device for the centrifugal pump becomes effective in terms of more effectively preventing liquid leakage from the vortex chamber and more effectively preventing wear of the seal packing.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention. Fig. 1 is a partially longitudinal side view of a centrifugal pump to which the leakage prevention device of the invention is applied, and Fig. 2 is a sectional view taken along the line A--A in Fig. 1. , Fig. 3 is a sectional view taken along the line CC in Fig. 4, which is a vertical sectional view of the leakage prevention device, Fig. 4 is a sectional view taken along the line B-B in Fig. 3, and Fig. 5 shows the stopped state of the centrifugal pump. FIG. 6 is a vertical side view of the centrifugal pump in an operating state. 1...Centrifugal pump, 2...Centrifugal pump body, 3
... Upper casing, 4 ... Lower casing, 5
...Rotating shaft, 6...Leakage prevention device, 7...Upper case, 8...Lower case, 9...Space, 10...
Moving member, 11... Outer ring, 12... Inner ring, 17... Seal ring body, 18, 25...
Guide pin, 19... Spring, 20... Boss, 22, 28... Partition wall, 23... Seal packing, 23a... Lip portion, 26... Mover,
26b...Groove, 27...Seal opening/closing pin, 27a
...Head, 29...Vortex chamber, 30...Impeller,
31... Seal blade, 32... Main blade.

Claims (1)

[Claims] 1 A centrifugal pump that sends liquid in a predetermined direction by rotating an impeller for pumping liquid in a vortex chamber is fixed to a rotating shaft to which the impeller is attached, and rotates together with the rotating shaft to pump the liquid. rotation of the axis,
A moving member is provided that moves along the rotating shaft and returns in conjunction with the stop, and the movement of the moving member opens and closes a gap in the shaft hole into which the rotating shaft is inserted, and the liquid in the vortex chamber is discharged. In the leakage prevention device for a centrifugal pump that prevents liquid from leaking through a gap in the shaft hole, a portion of the movable member closer to the swirl chamber includes:
It moves and returns along the rotating shaft in the direction of the shaft hole together with the moving member, and as it does so, contacts and separates from a seal packing attached to the outer wall of the shaft hole to seal and release the gap in the shaft hole. A liquid leakage prevention device for a centrifugal pump, characterized in that a rotatable seal ring body is attached to the movable member.