JP3292547B2 - Submersible pump vibration suppressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for preventing vibration of a submersible pump for stirring or transferring contents provided in a storage tank for radioactive waste (sludge) generated in a nuclear facility.

[0002]

2. Description of the Related Art As is well known in the art, a tank for storing sludge is provided with a submersible pump for stirring the contents and transferring the sludge out of the tank. Among them, the submersible pump of the type fixed at the center of the tank is guided by an elevating guide facility installed inside the tank to prevent vibration.

[0003] On the other hand, in a tank storing sludge without any extraction facility, the sludge is extracted by means such as hanging a submersible pump using an overhead crane or the like. It was very difficult to add an elevating guide to the existing tank, and in consideration of vibration prevention, the submersible pump could not be suspended and sludge extraction was difficult.

[0004]

As described above, in the prior art, it was sometimes difficult to extract sludge from the sludge storage tank.

The present invention has been made in view of such circumstances, and it is intended to prevent the expansion of vibration of a suspended installation type submersible pump, and to extract sludge from a stored tank without an extraction facility. It is an object of the present invention to provide a submersible pump vibration preventive device that also enables.

[0006]

According to the first aspect of the present invention, a submersible pump for suspending or stirring contents in a radioactive waste storage tank is suspended from a ceiling side by a vibration preventing cable. The device, wherein the vibration prevention cable includes:
It consists of a plurality of ropes suspended from different parts above the tank with a lower convergent slope, and the inclination angle θ of each of these ropes from the vertical line is the seismic force corresponding to the natural period of the single pendulum of the submersible pump. When the acceleration is αg and the gravitational acceleration is g, it is characterized in that settings are made so as to satisfy the equation θ> tan ⁻¹ α.

According to a second aspect of the present invention, in the first aspect of the present invention, there are provided three or more ropes as vibration preventing ropes, and the reel is wound around a crane on a tank, a bogie mounted on the crane, or a building wall. It is attached via the device.

According to a third aspect of the present invention, in each of the first and second aspects of the present invention, each of the ropes as an anti-vibration rope is provided separately from a vertical submersible pump suspension rope, and a winding device for each of the ropes is electrically driven. It has a lock mechanism, an ON / OFF switch, and a winding spring mechanism. The lock mechanism is set to lock when the switch is ON and to unlock when the switch is OFF.

[0009]

According to the submersible pump vibration preventing device of the first aspect,
By suspending the submersible pump with a plurality of ropes as anti-vibration ropes stretched at an angle equal to or greater than a certain angle from the vertical direction, the degree of freedom regarding pendulum vibration of the submersible pump becomes zero. Therefore, at a small earthquake acceleration, the submersible pump does not vibrate with a pendulum, and can prevent a co-seismic earthquake.

On the other hand, since the acceleration is large in the short-period component of the seismic motion component, in the region where the inclination of one or more of the ropes is larger than the value of the remaining ropes in the inclined ropes, the remaining Excitation vibration occurs when the cord is loosened.

However, in this case, no resonance occurs because the natural period of the simple pendulum is separated from the period of the seismic motion component. This vibration is a steady vibration and its amplitude is sufficiently small, so that the vibration of the pump does not cause a collision with the surrounding structure. As described above, prevention of vibration expansion is achieved.

Therefore, according to the present invention, the anti-vibration rope can be installed at a very small angle as shown in Table 1. As a result, it is possible to attach a vibration prevention line to the overhead crane, and to provide a movable sludge extraction facility that has a vibration expansion prevention function and does not require modification on the tank side.

According to the second aspect of the present invention, the vibration expansion preventing function can be obtained in each direction on the plane by using three or more ropes as the vibration preventing rope.

According to the third aspect of the present invention, the power supply of the wire winding device only needs to be turned on when the pump is moved up and down, and the power supply only needs to be turned off when the pump is operated, so that the switching operation can be easily performed. When the power is lost, the anti-vibration function can be exhibited.

[0015]

An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show the overall structure of a submersible pump vibration preventing device according to the present embodiment. FIG. 3 shows a component structure, and FIG. 4 shows a vibration preventing action.

A sludge storage tank 2 is installed in a building 1 of a nuclear facility. The building 1 is located above the tank 2
An overhead crane 3 supported via a guide rail 1a is disposed on the overhead crane 3, and a bogie 4 is mounted on the overhead crane 3.

A suspension chain 5 is suspended from the carriage 4 via a chain block (not shown). A submersible pump 6 for stirring or transferring sludge is suspended from a lower end of the suspension chain 5. That is, the submersible pump 6 is movable, and can be moved up and down by a winding drum (not shown) provided on the carriage 4, and can be moved laterally in the tank 2 together with the carriage 4.

In this embodiment, four ropes, for example, wires 8 are provided as vibration preventing ropes 7 of the submersible pump 6. Each of these wires 8 is led horizontally from a plurality of winding devices 9 attached to different parts on the ceiling side of the building 1, wound around a pulley 11 attached to the overhead crane 3 via a support 10, and The submerged pump 6 is pulled out with a lower convergent inclination angle and is connected to one point of the submersible pump 6. In addition,
Reference numeral 12 denotes a support for the winding device 9.

As shown in FIG. 3, the winding device 9 winds the winding drum 9a, an electric lock mechanism 13 such as an electromagnetically driven disk brake, an on / off switch 14, and a drum 9a. And a winding spring mechanism 15 for urging in the direction. Then, the switch 14 is turned on by the lock mechanism 13.
It is set to be in a non-locked state at the time and a locked state at the time of OFF.

Normally, when the submersible pump 6 is pulled out of the tank 2 and the contents of the sludge storage tank 2 need to be stirred or transferred out of the tank,
The submersible pump 6 is lowered into the sludge storage tank 2 by extending the suspension chain 5 as shown in FIG. In this case, the winding device 9 of the wire 8 is unfixed so that the wire 8 can be unwound when the power is turned on, and the wire 8 is wound when the power is turned off.
Is fixed so as not to be extended. That is, the switch 14
By turning on the power of the winding device 9 of the cable body 8 by the operation of, the four wires 8 are also simultaneously fed out, and the power is turned off.
By doing so, the wire 8 is not fed out.

Therefore, when the power is turned on by operating the switch 14, the disc brake of the lock mechanism 13 separates from the drum 9a and maintains a state of non-contact with the drum 9a. At this time, the drum 9a is fixed only by the force of the spring 15. Therefore, when the pump 2 is lowered by extending the suspension chain 5, the load of the submersible pump 6 applied to the wire 8 exceeds the elastic force of the spring 15, so that the drum 9a rotates and the wire 8 is extended. When hoisting the lifting chain 6, the elastic force of the spring 15 exceeds the load of the submersible pump 6, so that the drum 9a rotates in the reverse direction and the wire 8 is wound.

When the power is turned off, the disc brake of the lock mechanism 13 cannot maintain the state of non-contact with the drum 9a, and returns to the original contact state. As a result, even if a force is applied to pull out the wire 8, the frictional force between the disc brake and the drum 9a is added to the elastic force of the spring 15, and the rotation of the drum 9a is prevented, and the wire 8 is locked.

In this embodiment, the wires 8 constituting the anti-vibration rope 7 are suspended from different portions above the tank 2 with a lower convergent slope. The inclination angle θ of each of the wires 8 is set to an angle corresponding to the natural period of the single pendulum of the submersible pump, at which vibration does not start with a small seismic force acceleration in the case of a long-period vibration dynamic component, thereby preventing the vibration from expanding Is planned.

This vibration expansion preventing function will be described in detail with reference to FIG.

FIG. 4 shows the balance of forces when vibration occurs.

[Analysis at the Time of Occurrence of Vibration] The required inclination angle θ of the auxiliary wire when the pendulum is statically balanced by the horizontal acceleration αg due to the earthquake is determined.

That is,

Equation 1 α cos θ = G sin θ From the above equation,

## EQU2 ## θ = tan ^-1 α.

Thus, the required support point dimension D is as follows.

[0030]

(Equation 3)

Therefore, if θ is set to be larger than this angle, the acceleration of gravity acts on the pump to decelerate the pump in the tangential direction of the vibration due to the acceleration of gravity acting on the pump, due to the acceleration of the seismic motion acting on the pump to accelerate the pump in the tangential direction of the vibration. The force to be applied is larger, and vibration is not started.

By substituting L and α into these equations, the required support point size (= D) and the required inclination angle (= θ) of the cord are obtained. In this case, the required inclination angle of the anti-vibration rope 8 is 3.
4 degrees, the required distance between the pulleys is 0.36 (=
0.18 × 2) m.

As described above, according to this embodiment, by giving the wire 8 an inclination angle θ or more, it is possible to prevent the suspension type submersible pump 2 from expanding its vibration.

Table 1 and FIG. 5 show the results in the case where the length of the hanging chain 5 is 3 to 8 m in the use state of the submersible pump 2.

[0035]

[Table 1]

The value of the floor acceleration in Table 1 is the acceleration response spectrum of the El Centro seismic wave (see FIG. 5).

According to the present embodiment, since the submersible pump 2 is suspended by the suspension chain 5 and the four wires 8, the degree of freedom regarding the pendulum vibration of the submersible pump 2 becomes zero. Therefore, the submersible pump 2 does not vibrate the pendulum at a small earthquake acceleration in the case of a long-period seismic motion component corresponding to the natural period of the single pendulum of the submersible pump.

In the above-described embodiment, the number of wires 8 as the anti-vibration ropes 7 is set to four, but this is the most effective and stable number for preventing the vibration from expanding in all directions on the horizontal plane. It is not limited to this.

For example, when the number of the wires 8 is set to two, the vibration expansion can be prevented in only one direction on a plane between the supporting points by the two-point support.

In the case of setting the number to three, the vibration expansion in all directions can be prevented substantially in the same manner as in the above embodiment by the three-point support.

Further, the present invention can be modified in various ways other than the above embodiment. For example, a support 10 for supporting the winding device 9 of the wire 8 may be attached to the overhead crane 2 or the trolley 3, and the pump may be hung only by the anti-vibration rope without using the hanger chain 5. Further, a chain may be used as the suspension prevention cable 7 instead of the wire.

[0042]

As described above, according to the present invention, the submersible pump is hung by a plurality of ropes inclined at a predetermined angle from the vertical direction to prevent the vibration of the submersible pump against an earthquake or the like with a simple configuration. Thus, excellent effects such as prevention of damage to pumps and tanks and effective prevention of radioactive contamination can be achieved.

In addition, sludge can be extracted from a sludge storage tank without a sludge extraction facility.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing one embodiment of the present invention.

FIG. 2 is a plan view of FIG. 1;

FIG. 3 is a diagram showing a component configuration of the embodiment.

FIG. 4 is an operation explanatory view of the embodiment.

FIG. 5 is a graph showing acceleration during an earthquake.

[Explanation of symbols]

 2 Tank 6 Submersible pump 7 Anti-vibration cable 8 Cable body (wire) θ Tilt angle

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Katsuo Katata 1st place, Shin-Nakahara-cho, Isogo-ku, Yokohama-shi, Kanagawa Ishikawajima-Harima Heavy Industries Co., Ltd. Yokohama Plant (56) References JP-A-3-56396 (JP, A) JP-A-5-59843 (JP, A) JP-A-62-135699 (JP, A) JP-A 61-56383 (JP, U) JP-A 61-48993 (JP, U) (58) (Int.Cl. ⁷ , DB name) F04D 13/08 B66C 17/06 F04B 39/00 F16F 15/02

Claims (3)

(57) [Claims] 1. A submersible pump vibration preventing device in which a submersible pump for stirring or transferring contents is suspended from a ceiling side by a vibration preventing cable in a radioactive waste storage tank,
The anti-vibration rope is composed of a plurality of ropes suspended from different portions above the tank with a lower convergent inclination, and the inclination angle θ of each of these ropes from the vertical line is unique to the single pendulum of the submersible pump. Αg is the seismic force acceleration corresponding to the cycle,
When the gravitational acceleration is g, the submersible pump vibration preventing device is set so as to satisfy the formula of θ> tan ⁻¹ α. 2. The cable body as an anti-vibration cable is three or more, and is attached to a crane on a tank, a bogie mounted on the crane, or a building wall via a winding device. The submersible pump vibration prevention device as described in the above. 3. Each of the ropes as a vibration-prevention rope is provided separately from a vertical submersible pump suspension rope, and a winding device for each of the ropes is provided with an electric lock mechanism, an ON / OFF switch and a switch. 3. The submersible pump vibration preventing device according to claim 2, further comprising a hoisting spring mechanism, wherein the lock mechanism is set to lock when a switch is turned on and to unlock when the switch is turned off.