JPS61293567A - Centrifugal separator - Google Patents

Abstract

PURPOSE:To safely and easily maintain and exchange a ball bearing for bearing the rotating shaft of a rotor by readily exchanging the ball bearing by remote operation. CONSTITUTION:A rotating shaft 8 for driving a rotor 7 is provided above a shielding wall 1 and ball bearings 11 and 10 are held by bearing housing 3 and 2. The bearing 10 is fixed to the bottom plate of the bearing housing 2 at the outer race, the bearing 11 is fixed to the upper surface plate of the bearing housing 2 at the outer race and a sleeve 19 having a tapered hole whose diameter is upwardly reduced is engaged with the inner race of the bearing 11. An inner bearing cap 20a to press the inner race of the bearing 11 is screwed into the sleeve 19 and a sliding ball sleeve 21 for holding a ball 23 for positioning the shaft 8 in the axial direction in cooperation with a ball groove 8f in the circumferential direction furnished to the rotating shaft 8 is engaged with the inner bearing cap.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to improvements in centrifuges.

[Technical Background of the Invention and Problems Therewith] A centrifugal clarifier conventionally used for solid-liquid separation of a radioactive liquid to be treated in a nuclear fuel reprocessing process has a structure shown in FIG. That is, bearing boxes 2.3 are stacked above the shielding wall 1 for preventing radiation damage to the bearings, etc., and the motor 4 is installed at the top of the bearing boxes 2.3. The output shaft 5 of the motor 4 is directly connected to a rotating body 7 disposed in a casing 6 provided below the shielding wall 1, and connected to a rotating shaft 8 passing through the shielding wall 1 via a shaft coupling 9. There is. ! The rotating shaft 8 is connected to ball bearings 10 and 1 provided in the bearing box 2.3.
1, it is rotatably supported in a vertical position.

In addition, 12 in the figure is a handling hole provided in the end plate of the rotating body 7;
3 penetrates the casing 6 and attaches to the inner periphery of the lower end of the rotating body [f;1
14 is a cleaning water supply pipe that also passes through the casing and extends into the rotating body 7 and has a closed end at the upper end of the rotating body; 15 is a cleaning nozzle provided on the cleaning water supply pipe; 16 is a cleaning nozzle provided on the cleaning water supply pipe; A drain pipe is provided on the bottom surface of the casing 6, 17 is a receiver provided on the upper part of the casing 6, and 18 is a recovery pipe attached to the lower part of the receiver.

In the centrifugal clarifier having the above configuration, the liquid to be treated is transferred to the motor 4.
It is continuously supplied to the rotating body 7 which is being rotated at high speed.

The supplied liquid to be treated is clarified in the rotating body 7, and this clarified liquid overflows from the extraction hole 12, is collected in the container 17, and is collected from the collection pipe 18 via a collection circuit (not shown).

The above clarification work will continue for a certain period of time. Thereafter, the rotating body 7 is stopped, and cleaning water is jetted from the cleaning nozzle 15 to wash and remove the sludge accumulated inside the rotating body 7, and the sludge is collected through the drain pipe 16 to prepare for the next cycle.

As is clear from the above, in this type of centrifugal clarifier, the bearing box and other equipment are installed above the shielding wall 1 in order to handle highly radioactive liquids.
I try to protect it from wires.

By the way, since the rotating body 7 rotates at high speed,
The ball bearings 10.11 supporting the rotating shaft 8 need to be replaced periodically. Ball bearings are the most important part in maintaining the rotational performance of the rotating shaft and require high-precision and highly reliable assembly, but in the case of centrifugal clarifiers installed in nuclear fuel reprocessing plants For example, unless a special maintenance area is established, workers cannot access the bearings to replace them. However, establishing a special maintenance area as described above is not preferable because it complicates the entire facility.

In recent years, maintenance and replacement of equipment has begun to be carried out by remote control, so that equipment can be maintained and replaced without exposing workers to radiation without having to set up a maintenance area that complicates the overall facility. Devices to be replaced by remote control must be able to be disassembled, assembled, and replaced with as simple an operation as possible, and must also be assembled with high precision by remote control.

[Object of the Invention] The present invention has been made based on the above circumstances, and it is possible to easily replace the ball bearing that supports the rotating shaft of a rotating body by remote control, and to increase the rigidity of the rotating shaft sufficiently. The purpose is to obtain a centrifugal separator that can maintain

[Summary of the Invention 1 The centrifugal valve M machine of the present invention is provided with upper and lower bearing boxes that hold a pair of upper and lower ball bearings that support a rotating shaft that drives a rotating body above a shielding wall. , in which a rotating body and a casing are provided below the shielding wall, the lower ball bearing is fixed to the bottom plate of the lower bearing box at its outer race, and the upper ball bearing is fixed to the top plate of the lower bearing box. A sleeve having a tapered hole whose diameter decreases upward is engaged with the inner race of the upper ball bearing, and the inner race of the upper ball bearing is pressed against the sleeve. The inner bearing holder is screwed together, and the inner bearing holder is slidably engaged with a ball sleeve that is positioned axially with respect to the rotating shaft in cooperation with a circumferential ball groove provided on the rotating shaft. It is characterized by the fact that

[Embodiment of the Invention] FIG. 1A, in which the same parts as in FIG. It is directly attached to the rotating shaft 8 at the portion 8a.

Further, a tapered portion 8b whose diameter decreases upward is provided at a portion of the rotating shaft 8 that passes through the upper end plate of the bearing box 2. A three-stage stepped sleeve 19 is engaged with the upper ball bearing 11, and the upper ball bearing 11 is attached to the rotating shaft 8 via the sleeve 19.

Note that a portion of the rotating shaft 8 above the tapered portion 8b is a small diameter portion 8c having the same diameter as the small diameter end of the tapered portion 8b. Furthermore, the upper end surface of the large diameter portion 8a to which the lower ball bearing 10 is attached and the upper portion of the small diameter portion 8C are as follows:
The tapered portions 8d8 and 8e are tapered in diameter toward the top. Further, a circumferential ball groove 8f is provided near the upper end of the small diameter portion 8C.

FIG. 1B shows an enlarged view of the mounting portion of the upper ball bearing 11. As shown in this figure, sleeve 1
An inner race of a ball bearing 11 is engaged with the first step from the bottom of the ball bearing 9, and this inner race is fixed to one sleeve by an inner bearing retainer 20a screwed onto the sleeve 19. A ball sleeve 21 that terminates above the ball groove 8 of the rotating shaft 8 is engaged with the bearing holder 20a. The ball sleeve 21 has an annular cavity in its lower inner surface, and a spring 22 that presses against the bearing retainer 20 is accommodated in this cavity. A plurality of ball holes 21a are provided at positions corresponding to the ball grooves 8f of the ball sleeve 21 and distributed in the circumferential direction. A ball 23 is housed in the ball hole 21a, and a ball presser 24 is engaged near the upper end of the ball sleeve 21. The ball presser 24 has a minimum diameter in the axial middle that is approximately equal to the diameter of the outer circumference of the ball sleeve. A spring 25 is installed between the ball presser 24 and the ball sleeve 21. Note that the spring force of the spring 22 should be greater than the spring force of the spring 25. Further, an outer bearing retainer 20b is brought into contact with the outer race of the ball bearing 11 in cooperation with a flange at the lower end of the ball sleeve 21 to limit its stroke.

In the centrifugal separator of the present invention having the above configuration, the bearings are replaced as follows.

In the centrifugal separator of the present invention, as shown in FIG.
, the members attached thereto, such as the ball bearing rig 10.11, the sleeve 19, the bearing presser 20, the ball sleeve 21, the ball presser 24, etc., can be handled as a unit of 1B. Therefore, by removing them as a unit and installing a new unit, the bearings can be easily replaced by remote control.

First, the motor 4 and bearing box 3 are removed by remote control, and the ball presser 24 of the currently installed unit is pushed down by remote control. Then, the minimum diameter portion of the ball holder is separated from the ball 23, the ball 23 becomes free, and the ball sleeve 21 is raised by the spring 22. At this point, lift and remove units 1 to 1. At this time, the ball 23 is removed from the ball groove 21 and does not prevent the ball sleeve 21 from rising.

Next, the new unit assembled in a safe place is brought in and installed at a predetermined location on the shielding wall 1, that is, on the d oil part of the rotating shaft 8 so as to cover the rotating shaft 8. In this state, the inner race of the ball bearing 10 and the sleeve 19 are not yet fitted into the corresponding large diameter portion 8a and tapered portion 8b of the rotating shaft 8.

At this point, the rotating shaft 8 is pulled up relative to the sleeve 19. Then, first, the small diameter portion 8c of the rotating shaft 8 fits into the straight portion of one of the sleeves. At this time, the lower ball bearing 10 is not yet fitted into the large diameter portion 8a° of the rotating shaft 8. When the rotating shaft 8 is pulled up further, the large diameter portion 8a of the rotating shaft 8
is engaged with the inner race of the lower ball bearing 10.

Although this fitting is quite a rough fit, since the upper fitting portion, which has already been fitted, serves as a guide, the fitting is relatively easy. When the rotating shaft 8 is further pulled up, the tapered portion 8b of the rotating shaft and the tapered portion of one of the sleeves fit tightly together, and the rotating shaft 8 is fixed.

Here, the ball presser 24 is pushed down to free the ball 23 and lower the ball sleeve 21 against the spring 22. If you release the ball presser 24 in this state, the ball 1 reaches 2.
4 is raised by a spring 25, and the ball 23 is placed in the ball groove 8.
The ball sleeve 21 and the rotating shaft 8 are connected to each other.

In the centrifugal separator of the present invention having the above configuration, the lower ball bearing 10, which has the largest load, is directly attached to the large diameter portion 8a of the rotating shaft 8, and the upper ball bearing 11, which has a relatively smaller load, has one sleeve. It is attached to the rotating shaft 8 via. In general, ball bearings with heavy loads need to be fitted to the rotating shaft with minimal play, whereas ball bearings with low loads can tolerate some play. In the present invention, as described above, the lower ball bearing is fitted with a slight play, and the upper ball bearing is fitted with a slight play, so that rotation performance is ensured while the bearing part Easy to assemble.

[Effect of the invention] In the centrifugal separator of the present invention, a worker directly performs detailed assembly to form a unit in a location where there is no risk of radiation exposure, and this unit can be replaced with the unit currently in use by remote control. Therefore, maintenance and replacement of ball bearings can be performed safely and easily. It will also improve the plant's operating rate. Furthermore, since there is no need to provide a special maintenance area, the overall structure of the plant does not become complicated.

[Brief explanation of drawings]

FIG. 1A is a vertical cross-sectional view of a bearing part according to an embodiment of the present invention, B is an enlarged vertical cross-sectional view of the main parts thereof, FIG. 2 is a vertical cross-sectional view of a unit of the bearing part, and FIG. FIG. 4 is a vertical cross-sectional view showing a state in which the shaft is attached, and FIG. 4 is a vertical cross-sectional view of the entire conventional centrifugal separation system. 1... Shielding wall 2.3... Bearing box 4... Motor 5... Output shaft 6... Casing 7...
・Rotating body 8...Rotating shaft 9...Shaft coupling 10.
11... Ball bearing 12... Extraction hole 13... Liquid to be treated supply pipe 14... Cleaning water supply pipe 15... Cleaning nozzle 16
...Drain pipe 17...Receptor 18...Recovery pipe 19...Sleeve 20a...Inner bearing holder 20b...Outer bearing holder 21...Ball sleeve 22.25...Spring 23・・・Ball 24・
・・Ball presser application agent

Claims (1)

[Claims] Upper and lower bearing boxes holding a pair of upper and lower ball bearings that support a rotating shaft that drives a rotating body are provided above the shielding wall, and the rotating body and the casing are provided below the shielding wall. , the lower ball bearing is fixed to the bottom plate of the lower bearing box at its outer race, the upper ball bearing is fixed to the top plate of the lower bearing box at its outer race, and the inner race of the upper ball bearing is fixed to the bottom plate of the lower bearing box at its outer race. is engaged with a sleeve having a tapered hole whose diameter decreases upward, and an inner bearing holder that presses the inner race of the upper ball bearing is screwed into this sleeve, and a rotating shaft is attached to this inner bearing holder. A centrifugal separator characterized in that a ball sleeve is slidably engaged to hold a ball for axially positioning the rotating shaft in cooperation with a circumferential ball groove provided in the centrifugal separator.