JPH11248886A - Centrifugal cleaning apparatus and its siphon pipe replacement device for discharge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the work for replacing siphon pipes and prevent the damage to component instruments by providing a start-up container for starting up the siphon pipe to a casing, connecting an exhaust pipe connecting to a vacuum exhaust system and a drain pipe whose lower end is water-sealed to the start-up container, inserting airtightly the outlet side of the siphon pipe into the start-up container. SOLUTION: A casing 14 is provided under a shield floor unit 2 as a treatment area 1. The lower part of a drive shaft 11 and a separate body 12 are housed rotatably in the casing 14. A start-up container 25 for starting a siphon pipe 20 is integrally provided to the casing 14. The siphon pipe 20 is shaped like a hollow cylinder. An exhaust pipe 26 connected to a vacuum exhaust system and a drain pipe 28 whose lower end is water-sealed in a receiving tank 27 are connected to the start-up container 25. By connecting the exhaust pipe 26 connected to the start-up container 25 to the vacuum exhaust system and evacuating the inside of the container 25 with the exhaust pipe 26 to drive the siphon pipe 20, the necessity of a piston is eliminated and simplify the structure of the device more suitable for replacement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal fining machine for separating solids and liquids in a nuclear fuel reprocessing plant, and more particularly to a centrifugal fining machine which facilitates replacement and maintenance of a discharge siphon tube and its discharge. The present invention relates to a siphon tube exchange device.

[0002]

2. Description of the Related Art Generally, a reprocessing plant recycles spent fuel extracted from a nuclear power plant.
The chemical extraction separation process is performed, and the undissolved solids contained in the dissolved solution of the spent fuel at the time are not only a hindrance at the time of extraction, but also cause clogging of pipes, etc.
This needs to be separated and removed.

[0003] Various solid-liquid separation techniques such as centrifugal sedimentation and filtration techniques are used to separate the insoluble solids. Among them, large-scale reprocessing plants generally have large processing capacity and secondary Centrifugal clarifiers are often used because they generate less waste.

A centrifugal clarifier used in such a reprocessing plant is disclosed, for example, in Japanese Patent Application Laid-Open No. 61-291052.
And Japanese Patent Application Laid-Open No. Sho 62-14957 and Published Technical Report No. 93-6322.

As an example, FIG. 13 shows the structure of a centrifugal clarifier disclosed in Japanese Patent Application Laid-Open No. 61-291052. This centrifugal finer is relatively widely used worldwide in large-scale commercial reprocessing plants because of its relatively simple structure and high reliability. The centrifugal clarifier is installed in a room called a cell for confining radioactive materials and shielding radiation, like the main equipment of a reprocessing plant.

In the centrifugal fining machine, as shown in FIG. 13, a processing area 1 for performing a separation process between a solid and a liquid is set below a shielding floor unit 2, and maintenance and inspection are performed on the shielding floor unit 2. Area 3 is set. The shielding floor unit 2 includes a shielding floor 4 forming a cell ceiling.
And a shielding plug 5 fitted to the shielding floor 4 and configured to be detachable upward, and a siphon pipe shielding plug 6 fitted to the shielding plug 5 and shielding a siphon pipe described later, Processing area 1 by this shielding floor unit 2
And the maintenance area 3 are isolated.

On the maintenance area 3 side, a motor mount 7 is installed on the shield floor unit 2, and a rotary drive device 8 such as an electric motor or a hydraulic motor is installed at the upper end of the motor mount 7. The drive unit 9 is constituted by the rotary drive unit 8 and the rotary drive unit 8. A drive shaft 11 is connected to an output shaft of the rotary drive device 8 via a flange joint 10, and a bottomed cylindrical separation cylinder 12 for centrifuging the liquid to be treated is fixed to a lower portion of the drive shaft 11. The rotary unit 13 is constituted by the flange joint 10, the drive shaft 11, and the separation cylinder 12.

Further, a casing 14 is provided below the shielding floor unit 2 which is the processing area 1, and a lower portion of the drive shaft 11 and a separation cylinder 12 are provided in the casing 14.
Are rotatably accommodated.

A large diameter portion is formed on the peripheral wall of the separation cylinder 12 by an upper end plate 12a and a lower end plate 12b, and a plurality of fins 15 as fluid receivers are arranged at equal intervals in the circumferential direction in the large diameter portion. Fixed. A boss connected to the drive shaft 11 is formed at the center of the bottom of the separation cylinder 12, thereby forming a torus-shaped liquid reservoir 16.

Therefore, the drive unit 9 installed on the upper part of the centrifugal fining machine is detachably attached to the drive shaft 11 via the flange joint 10, and is easily detached from the flange joint 10 during maintenance, thereby facilitating maintenance. I have to.

The separation cylinder 12 drives the rotary drive device 8 installed at the upper end of the motor base 7 to rotate the drive shaft 11 and rotate the liquid to be processed supplied from the pipe system 17 to centrifuge. To separate. When the liquid to be treated is centrifuged,
Suspended particles having a large specific gravity in the liquid to be treated are pressed against the wall surface of the upper end plate 12a to form a furnace lump (cake), while the clarified liquid flows into the overflow space 1 through the annular passage 18.
9 overflows.

The cake as a solid separated by the centrifugal clarifier is washed with a spray or the like (not shown), and the solution containing the cake fragment is drained from the liquid reservoir 16 of the separation cylinder 12 by the siphon tube 20. Dispensed and discharged.
The siphon tube 20 has a structure that is started by pulling up a piston 21.
Is installed on the bottom surface of the siphon pipe shielding plug 6 provided above the siphon pipe 20. When the siphon tube 20 is started, priming water is supplied from the tube 22 in advance.

[0013]

As described above, the centrifugal clarifier shown in FIG. 13 has a large processing capacity, a relatively simple structure, and high reliability, and is widely used in large-scale commercial-scale reprocessing plants. Although it is used, if the siphon tube 20 or the like breaks down, it is necessary to replace the siphon tube 20.

In particular, since the piston 21 has a complicated structure including a movable portion, there is a possibility of failure, and the siphon tube 20 is capable of supplying a liquid containing a large amount of insoluble solids at a relatively low flow rate. Since the transfer pressure is only the hydrostatic head unlike the forced pressure of a pump etc.,
There is also the possibility of blockage. Considering this point,
The centrifugal clarifier disclosed in Japanese Patent No. 291052 recommends the installation of a spare siphon and has a structure in which the siphon tube 20 can be pulled out upward.

However, since the siphon tube 20 is in direct contact with the solution of spent fuel and has a high radiation level, its replacement and maintenance are extremely difficult. Therefore, in the prior art, the siphon tube 20
Although a method of performing decontamination of radioactive substances adhering to the surface in advance and lowering the radiation level sufficiently before performing the replacement operation is employed, the radiation is not completely eliminated. In particular, since the radioactive fluid is in contact with the piston 21 provided for starting the siphon and the pipe 22 for supplying priming water and the structure is complicated, it is difficult to decontaminate radioactive substances attached to the inside or the periphery thereof. There were challenges.

When replacing the siphon tube 20, in order to minimize the exposure dose of the worker within the legally allowable value and minimize the exposure dose, a shielding wall is partially provided around the periphery to be temporarily prepared.
In addition, so that radioactive materials do not scatter
Since a method of performing work while covering with a sealing sheet is adopted, there is a problem that workability is extremely poor and replacement work is difficult.

[0017] However, even if such protection is provided, in order to reduce the exposure dose as much as possible, it is necessary to perform the work while changing workers, and therefore, the workability in the control area is poor.
Since the siphon tube shielding plug 6 and its piston 21 may be bulky, there has been a problem that a large amount of time and a large number of workers are required as compared with the case where the siphon tube shielding plug 6 and the piston 21 are operated in a normal non-radiation environment.

Further, the centrifugal fining machine is a high-speed rotating machine, and requires high assembly accuracy.
There is a high-precision fitting structure between the cable and the siphon pipe shielding plug 6, and although handling such as attachment and detachment requires caution, work as described above Since there is no choice but to be made, the fitting parts may collide with each other, and there is also a problem that the parts are damaged and no longer function.

Furthermore, conventionally, not only the exchange work itself takes much time but also the exchange work requires advance preparation.
Many incidental operations such as sufficient decontamination of equipment, installation and removal of a temporary shield, installation and removal of a cover with a sealing sheet, and the like, required a long operation stoppage period. The centrifugal fining machine is one of the main processes of the plant, and if the operation is stopped for a long period of time, the operation of the plant will be hindered, and the operation rate of the plant will be reduced.

The present invention has been made in view of the above circumstances, and a centrifugal fining machine and a siphon tube changing device for discharging the same are easy and safe to replace the siphon tube without damaging the components. The purpose is to provide.

[0021]

In order to solve the above-mentioned problems, a first aspect of the present invention is a processing area for performing a separation process of a solid and a liquid and a maintenance and inspection set above the processing area. A shield floor unit for isolating the maintenance area, a rotary drive device provided on the maintenance area side of the shield floor unit, a vertical drive shaft driven by the rotary drive device and penetrating through the shield floor unit; A casing, which is connected to a shaft and is arranged in the processing area and accommodates a rotating part composed of a separation cylinder for centrifugally separating the liquid to be treated. A start-up container for starting a siphon tube for discharging a solution containing the collected cake fragments is attached, and the start-up container has an exhaust pipe connected to a vacuum exhaust system. A drain pipe whose end is water-sealed is connected, and the outlet side of the siphon pipe is hermetically inserted into the starting container, and the inside of the starting container is exhausted by an exhaust pipe connected to the vacuum exhaust system. And make it more negative than the atmosphere.

According to a second aspect of the present invention, in the centrifugal finer according to the first aspect, a funnel-shaped support surface is provided on the upper surface of the insertion hole of the starting container on the siphon tube outlet side, and the siphon tube has a spherical surface portion. A biasing means for forming a portion and applying a downward load to the siphon tube is provided, and the spherical surface of the enlarged diameter portion is pressed against the supporting surface of the insertion hole by the biasing means.

According to a third aspect of the present invention, in the centrifugal finer according to the second aspect, a seal ring is provided at an enlarged diameter portion of the siphon tube which is in pressure contact with the insertion hole of the starting container.

According to a fourth aspect of the present invention, in the centrifugal finer according to the first aspect, the shielding floor unit includes a shielding plug provided with a rotating part and a siphon pipe shielding plug for shielding the siphon pipe. It has two layers of a gamma ray shielding material and a neutron shielding material.

According to a fifth aspect of the present invention, in the centrifugal finer according to the fourth aspect, two sets of upper and lower seal rings are mounted on the outer periphery of the siphon pipe shielding plug, and pressurized air can be supplied between these seal rings. A pressurizing hole is provided.

A sixth aspect of the present invention is the centrifugal clarifier according to the first or fourth aspect, wherein the siphon tube is fixed to the siphon tube shielding plug.

A siphon tube for discharging a solution containing cake fragments accumulated in a separation cylinder for centrifuging a liquid to be treated and a siphon tube shielding plug for shielding the siphon tube and provided in a shielding floor unit. A cylindrical shielding container that can be stored integrally from the lower end opening, an opening and closing device that can airtightly close the lower end opening of the shielding container, and a gripper that grips the integrated siphon pipe shielding plug and siphon pipe. A hoisting device for winding the wire fixed to the lower end thereof from above the shielding container and pulling up the siphon tube shielding plug and the siphon tube integrally; and pulling up the siphon tube shielding plug installed on the inner wall of the shielding container. A guide rail for guiding the direction, and a holding device for holding the positions of the siphon pipe shielding plug and the siphon pipe after being lifted by the shielding container. Characterized by comprising and.

According to an eighth aspect of the present invention, in the centrifugal clarifier discharge siphon tube exchanging apparatus according to the seventh aspect, the opening and closing device includes a slidable openable and closable container opening and closing device capable of airtightly closing the lower end of the shielding container. The floor plug is characterized by comprising a sliding-type openable and closable floor opening / closing device capable of airtightly closing a floor opening of a shielding plug of the floor unit.

According to a ninth aspect of the present invention, in the siphon tube exchanging device for a centrifugal fining machine according to the seventh aspect, the opening and closing device comprises: It is characterized in that a sliding-type openable and closable floor opening / closing section that can airtightly close the shield plug floor opening of the floor unit is incorporated therein.

According to a tenth aspect of the present invention, in the siphon tube exchanging apparatus for a centrifugal clarifier according to the seventh or eighth aspect, a high-pressure spray nozzle that penetrates a pipe above the shielding vessel and injects washing water to a tip of the pipe is provided. On the other hand, a drain pipe for discharging the water after washing is installed in the container opening / closing device at the lower end of the shielding container.

According to a eleventh aspect, in the siphon tube exchanging device for a centrifugal fining machine according to the seventh aspect, a steadying member is provided on the inner wall of the shielding vessel to hold the suspended siphon tube. I do.

According to a twelfth aspect of the present invention, in the siphon tube exchanging device for a centrifugal finer according to the eighth aspect, a guide bolt is provided upright on the shielding plug, and a guide hole fitted to the guide bolt is provided with a container opening / closing device. And a floor opening and closing device.

[0033]

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

[Embodiment of Centrifugal Finer] FIG. 1 is a longitudinal sectional view showing the entire structure of an embodiment of a centrifugal finer according to the present invention. Parts that are the same as or correspond to the conventional configuration will be described using the same reference numerals as in FIG.

As shown in FIG. 1, a processing area 1 for separating solid and liquid is set below a shield floor unit 2, and a maintenance area 3 for maintenance and inspection is set on the shield floor unit 2. ing. The shielding floor unit 2 includes a shielding floor 4 forming the ceiling of the cell and the shielding floor 4.
A shielding plug 5 configured to be fitted to and detachable from above,
The siphon tube shielding plug 6 is fitted to the shielding plug 5 to shield the siphon tube 20, and the processing area 1 and the maintenance area 3 are separated by the shielding floor unit 2.

On the maintenance area 3 side, a motor mount 7 is installed on the shield floor unit 2, and a rotary drive device 8 such as an electric motor or a hydraulic motor is installed at the upper end of the motor mount 7. The output shaft 8a of the rotary driving device 8 includes:
The drive shaft 11 is connected via the bearing 23 and the flange joint 10, and the drive shaft 11 passes through a vertical hole 24 formed in the shield plug 5. The motor mount 7, the rotary drive device 8 and the bearing 23 constitute a drive unit 9, which is detachably attached to the drive shaft 11 via a flange joint 10. A cylindrical bottomed cylinder 12 for centrifuging the liquid to be treated is fixed to the lower part of the drive shaft 11, and the rotating part 13 is constituted by the flange joint 10, the drive shaft 11 and the separation cylinder 12. .

Further, a casing 14 is provided below the shielding floor unit 2 which is the processing area 1, and a lower portion of the drive shaft 11 and the separation cylinder 12 are provided in the casing 14.
Are rotatably accommodated.

A large diameter portion is formed on the peripheral wall of the separation cylinder 12 by an upper end plate 12a and a lower end plate 12b, and a plurality of fins 15 are fixed at equal intervals in the circumferential direction as a fluid receiver in the large diameter portion. Have been. A boss connected to the drive shaft 11 is formed at the center of the bottom of the separation cylinder 12, thereby forming a torus-shaped liquid reservoir 16.

The casing 14 is provided with a starting container 2 for starting the siphon tube 20 which is formed in a hollow cylindrical shape.
The starting container 25 has an exhaust pipe 26 connected to a vacuum exhaust system, and a lower end provided with a receiving tank 27.
A water-sealed drain pipe 28 is connected inside, and an insertion hole 29 is formed at the upper end as shown in FIG.
2 and 3, a funnel-shaped support surface 29a is formed on the upper part of the plate 9.

On the other hand, as shown in FIG. 2, the siphon tube 20 has a first arm portion 30, an inclined portion 31, and a second arm portion 3.
2, the first arm 30 is inserted into the hole of the shielding plug 5 and the lower end thereof is formed into a liquid reservoir 1.
6, the second arm 32 is inserted into an insertion hole 29 formed in the upper end of the starter container 25, and the lower end extends to the vicinity of the drain pipe 28. Then, the second arm 32
An enlarged diameter portion 33 is integrally formed at the upper part of the insertion hole, and a spherical surface portion 33a is formed on the lower surface of the enlarged diameter portion 33. The spherical surface portion 33a is a funnel-shaped support surface 29a of the insertion hole 29. And both adhere to each other.

Here, the surface roughness of the surface of the support surface 29a and the spherical surface portion 33a of the enlarged diameter portion 33 are controlled, and are sufficiently finished. The support surface 29a is subjected to a surface hardening treatment (build-up).

The siphon tube 20 has an inclined portion 31
Is fixed to a support plate 34 via a connecting portion 35. Two bolt insertion holes 36a and 36b are formed in the support plate 34, and bolts 37a and 37b are loosely fitted into the bolt insertion holes 36a and 36b, respectively. And is fixed to the bottom of the siphon tube shielding plug 6.

The first arm 3 on the lower surface of the support plate 34
A fulcrum rod 38 protruding downward is fixed near the 0 side, and the lower end of the fulcrum rod 38 is in contact with the upper part of the opening surface of the shielding plug 5. Further, a spring 39 as an urging means is mounted between the support plate 34 of the bolt 37b and the siphon tube shielding plug 6, and the urging force of the spring 39 causes the siphon tube to pass through the support plate 34 and the connecting portion 35. A downward load is applied to the 20 inclined portions 31.

Here, the support plate 34 on the first arm portion 30 side
Since the fulcrum rod 38 is in contact with the upper part of the opening surface of the shielding plug 5, the urging force of the spring 39 acts on the support plate 34 on the second arm 32 side, and A spherical surface portion 33 a formed on the lower surface of the enlarged diameter portion 33 of the two-arm portion 32 is pressed against the funnel-shaped support surface 29 a of the hole 29.

As shown in FIGS. 1 and 4, the siphon tube shielding plug 6 is composed of two layers of a gamma ray shielding member 40 made of tungsten and a neutron shielding member 41 and a cover 4 made of stainless steel.
2, two sets of seal rings 43 on the upper and lower sides of the outer periphery of the siphon pipe shielding plug 6 as shown in FIG.
Is installed. A pressurizing hole 44a is formed in the siphon pipe shielding plug 6 between the seal rings 43 in a horizontal direction, and communicates with the pressurizing hole 44a in a vertical direction to extend to the upper surface of the siphon pipe shielding plug 6. Pressing hole 44b
Are drilled. Further, a stepped portion 45 is formed on the outer peripheral surface of the siphon tube shielding plug 6 for holding the siphon tube 20 by a holding device described later when the siphon tube 20 is replaced.

Next, the operation of the centrifugal clarifier in the present embodiment will be described.

When the rotary drive device 8 installed at the upper end of the motor base 7 is driven, the bearing 23 and the flange joint 10 are driven.
The separation cylinder 12 rotates via the drive shaft 11 and the pipe system 1 is assisted by the plurality of fins 15.
The liquid to be treated supplied from 7 (the fuel solution in the case of reprocessing) is centrifuged.

When the liquid to be treated is centrifuged, suspended particles having a large specific gravity in the liquid to be treated are pressed against the wall surface of the upper end plate 12a to form a furnace lump (cake), while the suspended particles are separated and clarified. The liquid overflows into the overflow space 19 through the annular passage 18 and is discharged to the outside.

The cake, which is the solid content separated by the centrifugal clarifier, is washed under high pressure by a spray or the like (not shown), and the solution containing the cake fragments falls into the liquid reservoir 16 of the separation cylinder 12. The solution that has fallen into the liquid reservoir 16 is withdrawn by the siphon tube 20 and received in the receiving tank 2.
It is discharged to 7. The siphon tube 20 is started by connecting the exhaust pipe 26 to a vacuum exhaust system and setting the inside of the starting container 25 to a negative pressure.

When the siphon tube 20 is replaced, the siphon tube shielding plug 6 and the siphon tube 20 are integrally pulled up from the shielding plug 5 by a winding device described later.

As described above, according to the centrifugal clarifier of the present embodiment, the exhaust pipe 26 connected to the starting vessel 25 is connected to the vacuum exhaust system, and the inside of the starting vessel 25 is set to a negative pressure by the exhaust pipe 26. By activating the siphon tube 20, the piston and the like are not required as compared with the related art, so that the interval between the siphon tube 20 and the siphon tube shielding plug 6 can be shortened, and further replacement is possible. A suitable simple structure can be obtained. As a result, the size of the part to be replaced can be reduced and simplified.

According to the centrifugal clarifier of the present embodiment,
The spherical surface portion 33a is formed on the lower surface of the enlarged diameter portion 33 of the siphon tube 20, while the funnel-shaped support surface 29a is formed in the insertion hole 29 of the starting container 25. Even if there is a slight inclination, the siphon tube 2 is automatically positioned at the optimum position.
0 and the starting container 25 can be sealed easily and reliably.

Further, the upper and lower parts of the siphon pipe shielding plug 6
Between the set of seal rings 43, siphon tube shielding plug 6
When the siphon pipe shielding plug 6 is inserted, pressurized air is supplied through the pressurizing hole 44b and the pressurizing hole 44a by forming the pressurizing holes 44a and 44b communicating with the upper surface of the
By measuring the pressure change, the seal ring 43 is measured.
Can be confirmed, and the reliability of the sealing function can be improved.

Further, the siphon pipe shielding plug 6 is
Gamma ray shielding material 40 and neutron shielding material 4 made of tungsten
Since the two layers 1 are covered with the cover 42 made of stainless steel, the shielding thickness can be reduced as compared with a shielding material such as simple steel or lead.

[Modification of Embodiment of Centrifugal Finer] FIG. 5
(A), (B) is a sectional view showing a modified example of the embodiment of the centrifugal finer according to the present invention, and showing a sealing mechanism between the siphon tube and the starting container. In the modification shown in FIG.
The enlarged diameter portion 33 is formed integrally with the upper part of the second arm portion 32, and a seal ring 46 is embedded in the outer peripheral surface of the enlarged diameter portion 33. Therefore, since the seal ring 46 is in close contact with the inner peripheral surface of the insertion hole 29, the space between the siphon tube 20 and the starting container 25 is hermetically sealed.

In the modification shown in FIG. 5B, the second
A cylindrical enlarged diameter portion 33 is integrally formed on an upper portion of the arm portion 32, and a seal ring 47 is mounted on a lower surface of the enlarged diameter portion 33. Therefore, since the seal ring 47 is in close contact with the opening surface of the insertion hole 29, the space between the siphon tube 20 and the starting container 25 is hermetically sealed. as a result,
The same effects as in the above embodiment can be obtained in each of the modified examples shown in FIGS.

[The first siphon tube exchange device of the centrifugal clarifier]
Embodiment] FIG. 6 is a longitudinal sectional view showing a first embodiment of a siphon tube exchange device for a centrifugal clarifier according to the present invention. This siphon tube exchange device 50 is applied when exchanging the siphon tube 20 in the centrifugal clarifier of the embodiment.

As shown in FIG. 6, the siphon tube exchanging device 50 of the centrifugal fining machine can house the siphon tube 20 and the siphon shielding plug 6 integrally, is formed in a cylindrical shape, and has a lower end portion. Shielding container 51 having opening 51a
And a container lower flange 52 fixed to the lower end of the shielding container 51 and having an opening 52a, and an opening 51a of the shielding container 51 and an opening 52a of the container lower flange 52 installed on the bottom surface of the container lower flange 52. A slidable openable and closable unit 53a that can be closed airtightly from the horizontal direction.
Container opening and closing device 53 having
A floor opening / closing device 54 having a slidable openable / closable opening / closing portion 54a which is detachably installed at the lower end of the housing 3 and which can airtightly close the floor opening of the shielding plug 5 from the horizontal direction.

The opening / closing portion 53a of the container opening / closing device 53 and the opening / closing portion 54a of the floor opening / closing device 54 are opened and closed by an opening / closing mechanism composed of, for example, a ball screw and a rotary driving device for rotating the ball screw. 51a and 52
a, respectively, open and close by moving forward and backward in the horizontal direction with respect to the floor opening of the shielding plug 5. A sealing member 55 is provided on the contact surface of each of the opening / closing portions 53a and 54a of the container opening / closing device 53 and the floor opening / closing device 54 when they are fully closed.

Two screw holes 56 are formed in the shielding plug 5 in advance, and two guide bolts 5 are formed in these screw holes 56.
7 are screwed up and set up in the vertical direction. Container opening / closing device 53 at each position facing these guide bolts 57
And guide holes 53 on the floor opening / closing device 54 side, respectively.
The opening / closing device 53 and the floor opening / closing device 54 are positioned by fitting the guide holes 53b and 54b into the guide bolts 57, respectively.

On the other hand, at the top of the shielding container 51, a hoisting device 59 for winding and unwinding the wire 58 with respect to the center of the shielding container 51 is installed, and at the lower end of the wire 58, for example, used in a nuclear reactor. A gripper 60 configured similarly to the fuel gripper is fixed. Therefore, when replacing the siphon tube 20, a gripping seat 61 is attached to the center of the upper surface of the siphon pipe shielding plug 6 in advance.
By driving the wire 9 and winding up the wire 58, the siphon tube 20 and the siphon tube shielding plug 6
Suspended inside.

In addition, the upper part of the shielding container 51
A holding device 62 is installed at equal intervals at a location, and the holding device 62 is attached to the shielding container 51 by a biasing means such as a spring.
The fixing pin 63 has a tapered portion 63a formed therein.
Normally, only the tapered portion 63a protrudes from the inner wall of the shielding container 51 in the axial direction.

Therefore, when the siphon tube shielding plug 6 and the siphon tube 20 are lifted in the shielding container 51, the upper peripheral end of the siphon tube shielding plug 6 is tapered.
a, the fixing pin 63 is retracted by pressing the upper portion of the siphon pipe shielding plug 6, and the upper portion of the siphon pipe shielding plug 6 passes through the fixing pin 63.
When the position 3 is reached, the fixing pin 63 projects below the stepped portion 45 to hold the siphon tube shielding plug 6, whereby the siphon tube 20 is also held in the shielding container 51.

Further, a pipe 64 penetrates from above the shield container 51 from above, and a high-pressure spray nozzle 65 for spraying washing water is attached to the end of the pipe 64, while a container at the lower end of the shield container 51 is provided. A drain pipe (not shown) for discharging water after washing is installed in the switchgear 53.

As shown in FIG. 7, a steadying member 66 for holding the siphon tube 20 from both sides is provided on the inner wall of the shielding container 51.
The height of these steadying members 66 in the shielding container 51 is set to a height corresponding to the vertical center of the siphon tube 20 when the siphon tube 20 is lifted. In addition, the steady rest member 66 is for holding the siphon tube 20 from both sides by the biasing force of the spring, and is installed so as to be movable in the radial direction of the shielding container 51 so that there is no problem when the siphon tube 20 is pulled up. It is stored on the inner wall of the shielding container 3.

As shown in FIGS. 6 and 8, guide rails 67 are attached to the inner peripheral surface of the shielding container 51 at three locations at equal intervals in the circumferential direction along the vertical direction. Then, on the upper surface of the siphon pipe shielding plug 6, FIG.
As shown in FIG. 3, three sets of guide mechanisms 68 are attached in advance at equal intervals in the circumferential direction.
Mounting positions coincide with the mounting positions (angles) of the three guide rails 67.

Further, the guide mechanism 68 has upper and lower two guide rollers 69 as shown in FIG.
The structure is always pressed against

Next, the operation of the siphon tube exchanging device of the centrifugal clarifier configured as described above will be described with reference to FIGS. 11 (A) to 11 (F).

When replacing the siphon tube 20 of the centrifugal clarifier, first, the drive unit 9 is removed from the shield floor plug 5 as shown in FIG. That is, the flange joint 10
Is removed from the drive shaft 11, and the motor base 7, the rotation drive device 8, and the bearing 23 are removed from above the shield floor plug 5.

Next, a gripping seat 61 is attached to the center of the upper surface of the siphon tube shielding plug 6, and three sets of guide mechanisms 68 are attached at equal intervals in the circumferential direction of the upper surface of the siphon tube shielding plug 6. Then, a guide bolt 57 is screwed into the screw hole 56 of the shielding plug 5 as shown in FIG.

Next, the siphon tube exchanging device 50 is carried into the upper part of the centrifugal clarifier using a crane or the like (not shown) and suspended. At this time, since the guide holes 53b and 54b of the container opening / closing device 53 and the floor opening / closing device 54 are respectively guided and positioned by the guide bolts 57, the center between the siphon pipe shielding plug 6 and the shielding container 51 can be relatively easily formed. Can be adjusted to Then, as shown in FIG. 11 (B), the floor opening / closing device 54 of the siphon tube exchange device 50 is fixed on the shielding plug 5 by a bolt (not shown) or the like.

Thereafter, as shown in FIG. 11C, the wire 58 is wound down by the hoisting device 59, and the gripper 60 is lowered. Further, after the gripper 61 is gripped by the gripper 60, the winding device 59 is driven to lift the siphon pipe shielding plug 6 and the siphon pipe 20. At this time, the seal between the siphon tube 20 and the starting container 25 can be easily removed because the siphon tube 20 is simply pressed by the spring 39 as shown in FIG.

The siphon tube 20 includes a connecting portion 35, a support plate 3
Since the siphon pipe shielding plug 6 is fixed to the siphon pipe shielding plug 6 via the bolt 4 and the bolts 37a and 37b, the siphon pipe 20 is simultaneously pulled up as shown in FIG. Also, at this time, since the guide roller 69 of the guide mechanism 68 is pulled up while pressing the guide rail 67 outward in the radial direction of the shielding container 51, the siphon pipe shielding plug 6 is always maintained at the center of the shielding container 51, and is caught. It is possible to prevent galling and the like beforehand.

When the siphon pipe shielding plug 6 is lifted in the shielding container 51, the siphon pipe shielding plug 6
The upper peripheral end of the plug pushes the tapered portion 63a to retract the fixing pin 63, and the upper part of the siphon pipe shielding plug 6 is
3, when the stepped portion 45 of the siphon shielding plug 6 reaches the position of the fixing pin 63 by further lifting up, the fixing pin 63 protrudes below the stepped portion 45 to hold the siphon pipe shielding plug 6, whereby the siphon pipe shielding plug 6 is held. The siphon tube 20 is also a shielding container 5
It is held within 1.

In this case, a position detector or the like is previously installed in the hoisting device 59, and when it is detected that the siphon tube 20 and the siphon shielding plug 6 have been lifted up, the holding device 62 is activated and the fixing pin 63 is released. You may make it protrude in the shielding container 51, catch the step part 45 of the siphon shielding plug 6, and prevent fall.

However, the siphon tube 20 is only supported at its upper end by the shielding container 51 as it is, and vibrates due to shaking at the time of transport, or in the worst case, collides with the inner peripheral surface of the shielding container 51. There is also a danger of damage.

Therefore, the vibration preventing member 66 is projected from the inner wall of the shielding container 51, and the vibration is suppressed by sandwiching the siphon tube 20 from both sides with the vibration preventing member 66. After the lifting and fixing of the siphon tube 20 are completed, the opening / closing portions 53a of the container opening / closing device 53 and the floor opening / closing device 54 are closed by an opening / closing mechanism (not shown) as shown in FIG. In this case, a closing detection mechanism is provided to prevent separation between the container opening / closing device 53 and the floor opening / closing device 54 when the opening / closing portions 53a and 54a are not completely closed.

After confirming that both the open / close portions 53a and 54a are completely closed, the shielding container 51 is lifted by a crane (not shown) as shown in FIG. 11 (F).
Thereafter, a replacement siphon tube is similarly set separately in the siphon exchange device 50, and attached to the centrifugal clarifier in the reverse procedure.

In this case, while the spherical surface portion 33a is formed on the lower surface of the enlarged diameter portion 33 of the siphon tube 20, the funnel-shaped support surface 29a is formed in the insertion hole 29 of the starting container 25, so that there is a slight inclination. However, since the siphon tube 20 is automatically positioned at the optimal position, the siphon tube 20 and the starting container 25 can be easily and reliably sealed simply by pushing the siphon tube 20 from above.

Further, since a structure such as a piston is not required as compared with the prior art, the distance between the siphon tube 20 and the siphon shielding plug 6 can be shortened. can do. Therefore, the overall height of the siphon tube exchange device 50 can be kept low, and the device can be reduced in size and workability can be improved. In particular, the ceiling height in the plant is often limited,
In consideration of workability such as a hanging allowance, it is desirable that the overall height of the siphon tube exchange device 50 be as low as possible, and this is also advantageous.

By the way, the inside of the shielding container 51 of the siphon tube exchanging device 50 may be slightly contaminated with a radioactive substance due to the operation of replacing the siphon tube 20. Even in this case, it is important to reuse the siphon tube exchange device 50 from the viewpoint of reduction of radioactive waste and effective use of resources, but decontamination is difficult.

Therefore, the siphon tube replacement device 50 of the present embodiment has a high-pressure spray nozzle 65 inside the shielding container 51.
Is installed, and the inside of the shielding container 51 can be washed by supplying the washing water from the pipe 64.
Easy decontamination. The waste water after the cleaning is discharged from a drain pipe (not shown) provided in the container opening / closing device 53 at the lower end of the shielding container 51.

As described above, according to the first embodiment of the siphon tube exchange device of the centrifugal clarifier, the sealed shielding vessel 5
Since the replacement work of the siphon tube 20 is performed by using 1, the replacement work of the siphon tube 20 can be performed easily and safely in a short period of time.

[Second part of the siphon tube exchange device of the centrifugal clarifier]
Embodiment] FIG. 12 is a longitudinal sectional view showing a second embodiment of a siphon tube exchange device for a centrifugal clarifier according to the present invention. The same or corresponding parts as those in the first embodiment will be described with the same reference numerals.

In the second embodiment, the container opening / closing device 5
Unlike the first embodiment in which the opening and closing device 3 and the floor opening and closing device 54 are provided, one opening and closing device 71 is provided on the bottom surface of the container lower flange 52 fixed to the lower end of the shielding container 51 as shown in FIG. The opening / closing device 71 includes a container opening / closing portion 72 that can be horizontally slidably opened and closed with respect to the opening 51 a of the shielding container 51 and the opening 52 a of the container lower flange 52, and the floor surface of the shielding plug 5. A slide-type openable and closable floor opening / closing part 73 capable of closing the opening from the horizontal direction in an airtight manner is incorporated. And the opening and closing device 71
The guide hole 71
a, and the guide hole 71 a is
, The opening / closing device 71 is positioned.

The bottom of the container opening / closing section 72 is provided with a recess 7.
On the other hand, a convex portion 73a is formed on the upper surface of the floor opening / closing portion 73 so as to fit into the concave portion 72a of the container opening / closing portion 72. Container opening / closing section 72 and floor opening / closing section 73
The protrusion 73a of the floor opening / closing portion 73 fits into the concave portion 72a of the container opening / closing portion 72, and the two slide integrally in the horizontal direction. Here, an opening / closing mechanism including, for example, a ball screw and a rotation driving device that rotationally drives the ball screw is attached to the floor opening / closing section 73.

Further, a seal ring 74 is mounted on the upper surface of the container opening / closing portion 72 at a position facing the lower end of the container lower flange 52. A plurality of screw holes 75 are formed on the upper surface of the container opening / closing section 72,
When the container opening / closing portion 72 is closed, fixing bolts 76 for fixing the container opening / closing portion 72 to the container lower flange 52 are provided at positions of the container lower flange 52 facing these screw holes 75, respectively.

Next, the operation of the present embodiment will be described. Hereinafter, only operations different from those of the first embodiment will be described.

When the opening / closing mechanism is driven to slide the floor opening / closing section 73 horizontally toward the floor opening, the container opening / closing section 72 fitted on the upper surface of the floor opening / closing section 73 is similarly shielded. The container 51 is slid horizontally toward the opening 51a of the container 51.

Next, when the floor opening / closing section 73 reaches the position for closing the floor opening, the driving of the opening / closing mechanism is stopped. Then, the fixing bolt 76 is screwed into the screw hole 75 of the container opening / closing section 72 and tightened. Then, the container opening / closing section 7
2 moves upward and joins the bottom surface of the container lower flange 52. In this case, since the seal ring 74 is attached to the upper surface of the container opening / closing portion 72, the container opening / closing portion 72 is in close contact with the bottom surface of the container lower flange 52 to seal the shielding container 51.

After confirming that the opening 51a of the shielding container 51 and the floor opening of the shielding plug 5 have been completely closed, the container lower flange 52 and the opening / closing device 71 are separated, and the shielding container 51 is separated by a crane or the like. lift. Other configurations and operations are the same as those of the first embodiment, and thus description thereof will be omitted.

As described above, according to the present embodiment, only one opening / closing device 71 is required, and the siphon tube exchanging device 50 is used.
Can be reduced in size and weight.

[0093]

As described above, according to the first aspect of the present invention,
According to the present invention, the casing is provided with a starting container for starting a siphon tube for discharging a solution containing cake fragments collected after washing of the separation cylinder, and the starting container has an exhaust pipe connected to a vacuum exhaust system. The lower end is connected to a water-sealed drain pipe, and the outlet side of the siphon pipe is hermetically inserted into the start-up container. By using a negative pressure, a piston or the like is unnecessary as in the related art, and a simple structure suitable for replacement can be obtained. As a result, the size of the part to be replaced can be reduced and simplified.

According to the second aspect, in the centrifugal clarifier according to the first aspect, a funnel-shaped support surface is provided on the upper surface of the insertion hole on the siphon tube outlet side of the starting container, while the siphon tube has a spherical surface portion. When the siphon tube is attached by forming a diameter portion and providing a biasing means for applying a downward load to the siphon tube, and pressing the spherical surface portion of the enlarged diameter portion against the support surface of the insertion hole with the biasing means. Even if the siphon tube has a slight inclination, it is automatically positioned at the optimal position, so simply pressing the siphon tube from above easily and securely seals the gap between the siphon tube and the starting container can do.

According to the third aspect, in the centrifugal fining apparatus according to the second aspect, a seal ring is provided at a large-diameter portion of the siphon tube which is in pressure contact with the insertion hole of the starting container. The seal between the siphon tube and the starting container can be easily and reliably sealed.

According to a fourth aspect of the present invention, in the centrifugal clarifier according to the first aspect, the shielding floor unit includes a shielding plug on which a rotating unit is installed and a siphon pipe shielding plug for shielding the siphon pipe. Since the plug has two layers of a gamma ray shielding material and a neutron shielding material, the shielding thickness can be reduced as compared with a shielding material such as simple steel or lead.

According to the fifth aspect, in the centrifugal clarifier according to the fourth aspect, two sets of upper and lower seal rings are mounted on the outer periphery of the siphon pipe shielding plug, and pressurized air is supplied between these seal rings. By providing a possible pressurizing hole, leakage of air from the seal ring can be confirmed, and reliability of the seal function can be improved.

According to the sixth aspect, in the centrifugal clarifier according to the first or fourth aspect, since the siphon tube is fixed to the siphon tube shielding plug, replacement of the siphon tube becomes easy.

According to the seventh aspect, the siphon tube for discharging the solution containing the cake fragments collected in the separation cylinder for centrifuging the liquid to be treated and the siphon tube shielding provided on the shielding floor unit for shielding the siphon tube A tubular shielding container capable of integrally storing a plug from a lower end opening, an opening / closing device capable of closing the lower opening of the shielding container in an airtight manner, and an integrated siphon pipe shielding plug and a gripper for gripping a siphon pipe When,
This gripper winds up the wire fixed to the lower end from above the shielding container, and a winding device that integrally pulls up the siphon tube shielding plug and the siphon tube, and a guide installed on the inner wall of the shielding container to guide the pulling direction of the siphon tube shielding plug. Since the rail and the siphon pipe shielding plug and the holding device for holding the position of the siphon pipe after being lifted in the shielding vessel are provided, the replacement of the siphon pipe using the sealed shielding vessel can be performed easily and easily. Work can be performed safely. Further, since the guide rail is provided on the inner wall of the shielding container, the siphon tube can be replaced more reliably without damaging the device. Furthermore, since the period required for replacement is extremely short, it is possible to avoid a decrease in the plant operation rate.

According to an eighth aspect of the present invention, in the siphon tube exchanging device for a centrifugal clarifier according to the seventh aspect, the opening and closing device is a slidable openable and closable container opening and closing device capable of airtightly closing the lower end of the shielding container. In addition, since the shield plug unit of the shield floor unit is constituted by a slide-type openable and closable floor opening / closing device capable of closing the floor opening of the shield plug hermetically, the replacement operation can be performed safely.

According to a ninth aspect of the present invention, in the siphon tube exchanging device for a centrifugal fining machine according to the seventh aspect, the opening and closing device is provided with a slidable openable and closable container opening and closing portion capable of closing the lower end of the shielding container airtightly. Incorporating a slidable openable and closable floor opening / closing unit that can airtightly close the shielding plug floor opening of the shielding floor unit enables the use of a single opening / closing device, making the device compact and lightweight. Can be achieved.

According to a tenth aspect, in the siphon tube exchange device for discharging a centrifugal clarifier according to the seventh or eighth aspect,
By penetrating the pipe above the shielding container and attaching a high-pressure spray nozzle that sprays cleaning water to the tip of the pipe, a drain pipe that discharges the water after cleaning is installed in the container opening and closing device at the lower end of the shielding container. Since the inside of the shielding container can be washed, decontamination can be easily performed.

According to the eleventh aspect, in the siphon tube exchanging device for a centrifugal clarifier according to the seventh aspect, a steadying member for holding the lifted siphon tube is provided on the inner wall of the shielding container. In addition, it is possible to suppress the deflection of the siphon tube after being lifted, and to prevent the siphon tube from being damaged due to vibrations during wheel feeding.

According to the twelfth aspect, in the siphon tube exchanging device for a centrifugal fining machine according to the eighth aspect, the guide bolt is provided upright on the shielding plug and the guide hole fitted to the guide bolt is provided for the container. Since the guide holes are guided by the guide bolts to position the container opening and closing device and the floor opening and closing device by drilling in each of the opening and closing device and the floor opening and closing device, the center of the siphon pipe shielding plug and the shielding container is positioned. Can be adjusted relatively easily.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an entire configuration of an embodiment of a centrifugal finer according to the present invention.

FIG. 2 is an enlarged view showing a siphon shielding plug and a siphon tube of FIG. 1;

FIG. 3 is an enlarged view showing an enlarged portion of the siphon tube of FIG. 2;

FIG. 4 is a sectional view showing the siphon shielding plug of FIG. 1;

FIGS. 5A and 5B are cross-sectional views showing a sealing mechanism between a siphon tube and a starting container in a modified example of the centrifugal clarifier according to one embodiment of the present invention.

FIG. 6 is a longitudinal sectional view showing a first embodiment of a siphon tube exchange device for a centrifugal clarifier according to the present invention.

FIG. 7 is a sectional view taken along line AA of FIG. 6;

FIG. 8 is a sectional view taken along line BB of FIG. 6;

FIG. 9 is an enlarged view showing a state where a guide mechanism is attached to the siphon shielding plug of FIG. 6;

FIG. 10 is a configuration diagram showing the guide mechanism of FIG. 9;

FIG. 11 is an explanatory view showing the operation of the siphon tube exchange device of the centrifugal clarifier of FIG. 6;

FIG. 12 is a longitudinal sectional view showing a second embodiment of the siphon tube exchange device of the centrifugal clarifier according to the present invention.

FIG. 13 is a longitudinal sectional view showing a conventional centrifugal finer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing area 2 Shielding floor unit 3 Maintenance area 4 Shielding floor 5 Shielding plug 6 Siphon pipe shielding plug 7 Motor gantry 8 Rotary drive 8a Output shaft 9 Drive 10 Flange joint 11 Drive shaft 12 Separator cylinder 12a Upper end plate 12b Lower end plate 13 Rotating part 14 Casing 15 Fin 16 Liquid reservoir 17 Pipe system 18 Annular passage 19 Overflow space 20 Siphon pipe 23 Bearing part 24 Vertical hole 25 Starter container 26 Exhaust pipe 27 Receiving tank 28 Drain pipe 29 Insert hole 29a Support surface 30 First arm Part 31 inclined part 32 second arm part 33 enlarged diameter part 33a spherical surface part 34 support plate 35 connection part 36a, 36b bolt insertion hole 37a, 37b bolt 38 fulcrum rod 39 spring (biasing means) 40 gamma ray shielding material 41 neutron shielding material 42 Cover 43 Seal Ring 44a, 44b pressurizing hole 45 stepped portion 46, 47 seal ring 50 siphon tube changing device 51 shielding container 51a opening 52 container lower flange 52a opening 53 container opening / closing device 53a opening / closing portion 53b guide hole 54 floor opening / closing device 54a Opening / closing part 54b Guide hole 55 Seal member 56 Screw hole 57 Guide bolt 58 Wire 59 Winding device 60 Gripping tool 61 Gripping seat 62 Holding device 63 Fixing pin 63a Taper portion 64 Pipe 65 High pressure spray nozzle 66 Steady stop member 67 Guide rail 68 Guide Mechanism 69 Guide roller 70 Spring 71 Opening / closing device 71a Guide hole 72 Container opening / closing part 72a Concave part 73a Convex part 73 Floor opening / closing part 74 Seal ring 75 Screw hole 76 Fixing bolt

Claims (12)

[Claims] 1. A shielding floor unit for separating a processing area for performing a separation process between a solid and a liquid and a maintenance area which is set above the processing area and for performing maintenance and inspection, and is provided on the maintenance area side of the shielding floor unit. Provided rotary drive,
A vertical drive shaft driven by the rotary drive unit and penetrating the shielding floor unit; and a rotating unit connected to the drive shaft and arranged in the processing area and configured to have a separation cylinder configured to centrifuge a liquid to be processed. In the centrifugal clarifier having a casing for accommodating, a start-up container for starting a siphon tube for discharging a solution containing a piece of cake collected after washing of the separation cylinder is attached to the casing, and the start-up container is provided with the start-up container. An exhaust pipe connected to a vacuum exhaust system and a drain pipe whose lower end is water-sealed are connected, and the outlet side of the siphon pipe is hermetically inserted into the starting vessel, and the inside of the starting vessel is evacuated. A centrifugal clarifier characterized by exhausting air through an exhaust pipe connected to the system to make the pressure lower than the atmosphere. 2. The centrifugal clarifier according to claim 1, wherein a funnel-shaped support surface is provided on the upper surface of the insertion hole on the siphon tube outlet side of the starting container, and a diameter-enlarging portion having a spherical surface portion is formed in the siphon tube. A centrifugal fining machine, further comprising: urging means for applying a downward load to the siphon tube, and pressing the spherical surface of the enlarged diameter portion against the support surface of the insertion hole by the urging means. 3. The centrifugal fining machine according to claim 2, wherein a seal ring is provided at an enlarged diameter portion of the siphon tube which is in pressure contact with the insertion hole of the starting container. 4. The centrifugal clarifier according to claim 1, wherein the shielding floor unit includes a shielding plug on which a rotating part is installed and a siphon pipe shielding plug for shielding the siphon pipe, and the siphon pipe shielding plug is a gamma ray shielding material. And a neutron shielding material. 5. A centrifugal clarifier according to claim 4, wherein two sets of upper and lower seal rings are mounted on the outer periphery of the siphon pipe shielding plug, and pressurized holes capable of supplying pressurized air between these seal rings. A centrifugal fining machine characterized by the perforation. 6. The centrifugal fining machine according to claim 1, wherein a siphon tube is fixed to a siphon tube shielding plug. 7. A siphon tube for discharging a solution containing cake fragments collected in a separation cylinder for centrifuging a liquid to be treated, and a siphon tube shielding plug provided in a shielding floor unit for shielding the siphon tube and opening the lower end of the siphon tube. A cylindrical shielding container that can be integrally stored from the container, an opening and closing device that can air-tightly close the lower end opening of the shielding container, a gripper that grips the integrated siphon pipe shielding plug and the siphon pipe, and a gripper. A hoisting device for winding the wire secured to the lower end from above the shielding container and lifting the siphon tube shielding plug and the siphon tube together; and guiding the pulling direction of the siphon tube shielding plug installed on the inner wall of the shielding container. And a holding device for holding the positions of the siphon pipe shielding plug and the siphon pipe after being lifted by the shielding container. A siphon tube exchange device for discharging a centrifugal clarifier. 8. The siphon tube exchanging device for discharging a centrifugal clarifier according to claim 7, wherein the opening and closing device is a slidable openable and closable container opening and closing device capable of airtightly closing a lower end of the shielding container, and a shielding floor unit. A siphon tube changing device for discharging a centrifugal clarifier, comprising: a sliding opening / closing floor opening / closing device capable of closing an opening of a shielding plug floor surface in an airtight manner. 9. The siphon tube exchanging device for discharging a centrifugal clarifier according to claim 7, wherein the opening / closing device includes a slidable openable / closable container opening / closing portion capable of airtightly closing a lower end of the shielding container, and a shielding floor unit. A siphon tube changing device for discharging a centrifugal clarifier, wherein a sliding-type openable and closable floor opening / closing unit capable of closing an opening of a shielding plug floor surface in an airtight manner is incorporated therein. 10. A siphon tube exchanging device for discharging a centrifugal clarifier according to claim 7 or 8, wherein a pipe is penetrated above the shielding vessel, and a high-pressure spray nozzle for spraying washing water is attached to a tip of the pipe. A drain siphon pipe exchange device for a centrifugal clarifier, wherein a drain pipe for discharging water after washing is installed in the container opening / closing device at the lower end of the shielding container. 11. The centrifugal fining apparatus according to claim 7, wherein a shake-preventing member for holding the lifted siphon tube is provided on the inner wall of the shielding container. Siphon tube replacement device for machine discharge. 12. The siphon tube changing device for discharging a centrifugal clarifier according to claim 8, wherein a guide bolt is erected on the shielding plug, and a guide hole to be fitted to the guide bolt is provided with a container opening / closing device and a floor. A siphon tube exchange device for discharging a centrifugal fining machine, which is provided in each of the opening and closing devices.