JPH0788401A - Clarifying machine - Google Patents

Abstract

PURPOSE:To extend the life of a clarifying machine by reducing bearing load at the time of usual operation and to enhance the earthquake resistance thereof by suppressing displacement at the time of an earthquake by suspending a separation cylinder by a drive shaft so as to make the same freely rotatable in a pendulum state and providing a buffer device and a deflection stopper. CONSTITUTION:A motor driver 33 is attached to the motor stand 22 of a casing 20 and a separation cylinder 24 centrifugally separating a liquid to be treated is received in the casing to be flexibly connected to the motor driver 33 and suspended from above by a drive shaft supported so as to be rotatable in a pendulum state. A coil spring 40 is provided between the drive shaft 30 and the motor stand 22 to impart recovery force and attenuation force is imparted by a buffer device 43 wherein a hydraulic damper 41 and a rubber damper 42 are combined in series and a deflection stopper 53 composed of a roll bearing is provided between the drive shaft 30 and the drive shaft through-hole 52 of a shield floor 21 on the side of the drive shaft.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clarifier, and more particularly to a centrifugal clarifier suitable for separating solids suspended in a radioactive solution of a nuclear power plant or a nuclear fuel cycle facility.

[0002]

2. Description of the Related Art In the fields of medicine, chemistry, foodstuffs, etc., removal or recovery of solid matter suspended in a liquid is frequently required. A solid-liquid separator is used for separation and removal of suspended solids and recovery thereof. Such solid-liquid separation is roughly classified into methods such as filtration, evaporation drying, and centrifugal sedimentation.

Among them, the centrifugal sedimentation separation method does not require clogging of the filter as in the filtration method, does not require replacement of the filter, and does not require a heat source such as a heater as in the evaporative drying method, thus saving energy. Widely used due to the advantages of being.

FIG. 8 shows a typical conventional centrifugal clarifier.
And what is shown in FIG. 9 is known. Such centrifugal separation techniques include, for example, Japanese Utility Model Laid-Open No. Sho 62-118541 and Japanese Patent Laid-Open No.
62-254856, JP 63-16064, JP 64-7
No. 0157, Japanese Patent Laid-Open No. 1-139160 and Japanese Patent Publication No. 1-3718
Publication No. 1 is known.

The centrifugal clarifier shown in FIGS. 8 and 9 shows a typical structure of a vertical shaft cylindrical centrifugal sedimentation separator, and this centrifugal clarifier has a cylindrical separation in a cylindrical casing 1. The barrel 2 is housed therein, and an upper end plate 3 and a lower end plate 4 having holes are attached to the separating barrel 2 so that centrifugal separation is performed in the separating barrel 2. The casing 1 is suspended by a plurality of support legs 5 via a support rod and a spring 6, and is elastically and flexibly supported.

On the other hand, the lower end plate 4 of the separating cylinder 2 is connected to a drive shaft 8 via a rib 7. The drive shaft 8 is rotationally driven by a motor drive device 9 such as an electric motor or a hydraulic motor, and the separation cylinder 2 rotates. The rotating portion of the drive shaft 8 is supported by a pair of bearings 11 provided in a bearing housing 10 suspended from the casing 1. The casing 1 is provided with a liquid supply nozzle 12 for supplying the liquid to be treated into the separation cylinder 2, an outlet nozzle 13 for the clarification liquid, a scraping blade 14 for scraping off the cake 19 which has been settled and separated, and this scraping blade 14. A moving device 15 such as an air cylinder that is moved via a mounting member 18 and a cake discharge port 16 for discharging the cake 19 scraped off are provided. A water washing nozzle 17 for washing the cake is connected to the liquid feeding nozzle 12.

In this centrifugal fining machine, the separation cylinder 2 is raised to a predetermined number of rotations by driving the motor of the motor driving device 9.
The liquid to be treated is supplied to the lower part of the separation cylinder 2 by a liquid supply nozzle 12. The supplied liquid to be treated is held on the inner surface of the separation cylinder 2 by centrifugal force.

The liquid to be treated held in the separation cylinder 2 is subjected to the action of a rotating centrifugal force, and while flowing in the separation cylinder 2, the solid content having a large specific gravity is sedimented and separated on the peripheral wall surface of the separation cylinder 2. And it becomes cake 19.

The clarified liquid from which the solid content has been separated overflows from the upper end plate 13 as shown in FIG.
Outlet nozzle that flows down between the inner peripheral surface of the
Emitted from 13.

When the solid-liquid separation treatment of a certain amount of the liquid to be treated is performed, the cake 19 increases on the inner surface of the separation cylinder 2, so the solid-liquid separation operation is stopped and the cake 19 is discharged. In this solid-liquid separation operation, when the liquid side contains the active ingredient, a washing operation is performed to recover the active ingredient contained in the cake 19. When the active ingredient is contained in the solid side,
In order to drive out the liquid remaining in the cake 19 and increase the purity, a washing operation is often performed first.

In the washing operation, the separation cylinder 2 is used after the liquid supply is stopped.
It is performed by supplying the washing liquid from the washing liquid nozzle 17 while rotating the. After the liquid to be treated in the separation cylinder 2 is replaced with the washing liquid, the rotation is stopped. Since the cake 19 is normally pressure-bonded, it remains attached to the inside of the separation cylinder 2.

Then, as shown in FIG.
While slowly rotating the separating cylinder 2 with a, the cake 19 attached to the inner surface is scraped off. The cake scraped off is discharged from the cake discharge port 16 to the lower part, and a series of solid-liquid separation operations is completed.

When the centrifugal separation operation is continued in this centrifuge, the cake 19 increases and an imbalance occurs and the separation cylinder 2
The unbalanced force that acts on is increased. If an unbalanced force is generated, an excessive force acts on the bearing 11, which may damage the device. Therefore, the entire device is supported by the spring 6 to absorb the unbalanced vibration.

In order to prevent resonance with the rated rotation speed, the spring stiffness is generally soft so that the natural frequency of the entire device is in the low range of several Hz, and at the time of start and stop, this natural frequency range is set. (For example, JP-A-1-139160 describes a rigid centrifuge supported by an elastic support device).

As another conventional example, there is one in which the entire apparatus is rigidly supported. Even in this case, however, the rotating body is supported so as to be soft and free to move due to absorption of unbalanced vibration. For example, in Japanese Patent Publication No. 4-37397, "Rotating Bowl Support Device in Centrifuge for Nuclear Fuel Reprocessing",
“A shield wall, a frame fixed to the upper side of the shield wall, a rotating bowl fixed to a lower end of the rotary shaft, and a rotation shaft that penetrates the shield wall and projects an upper portion into the frame, and rotates the frame in the frame. A support device for a rotating bowl in a nuclear fuel reprocessing centrifuge, comprising: two bearings for supporting a shaft; and driving means fixed to the frame and coupled to an upper end of the rotating shaft for rotationally driving the rotating shaft. The diameter of the portion of the rotary shaft supported by the two bearings is set to 1/3 to 1/5 of the diameter of the lower portion, and the upper bearing of the two bearings is fixed to the frame, Moreover, the supporting device for the rotating bowl in the nuclear fuel reprocessing centrifuge characterized in that the lower bearing is attached to the frame so as to be movable substantially horizontally in the horizontal direction through an elastic member. Axis of It is characterized in that supported by the spring.

Further, in Japanese Patent Laid-Open No. 4-247251, "Solid-Liquid Separating Device" describes "a motor mount provided on a casing, a motor driving device attached to the motor mount, and a housing accommodated in the casing. And a separation cylinder for centrifuging the liquid to be treated, and while suspending the separation cylinder from above,
A drive shaft flexibly connected to the output side of the motor drive device, a support device that supports the drive shaft so that the drive shaft can rotate like a pendulum, and a restoring force is applied between the drive shaft and the motor mount. A shock absorber that provides a spring element and a damping element that provides a damping force, and a liquid supply device that supplies the liquid to be treated into the separation cylinder,
A device for discharging a clarified liquid, and a washing spray device for washing off the settled and separated solid content on the inner surface of the separation cylinder, wherein a plurality of baffle plates extending in the axial direction are provided in the separation cylinder. Separation device ".

Also in this device, the rotating system consisting of the drive shaft and the separating cylinder is supported so that pendulum-like vibration can be applied, and the primary critical speed of the entire rotating system is set to 5 by the shock absorber.
By supporting it softly so that the rotation speed is lower than Hz, it is devised to absorb the imbalance. As a similar example, Japanese Patent Publication No. 1-49549 “Centrifuge”
There is.

[0018]

The conventional centrifugal sedimentation separator supports softly in order to absorb the imbalance force. Therefore, at the time of an earthquake, resonance with the seismic force occurs, which may cause damage to the device or damage due to contact between the rotating body and the stationary body. The predominant frequency of the place where the seismic wave device is installed is generally 10 Hz or less, usually about 1 to 6 Hz, which is in a range where resonance with the device is extremely likely to occur.

Therefore, there is a high possibility that the seismic wave will be amplified and the device will be damaged. This is a device especially for handling hazardous materials,
For example, it has become an extremely important issue in the purification of chemical raw materials, the separation of harmful substances, the reprocessing of nuclear fuel, and the like.

In order to prevent damage due to an earthquake and improve earthquake resistance, for example, a spring is strengthened so as not to resonate with the earthquake, a damping force is increased by a damper, or a spring or damper is temporarily strengthened by detecting seismic waves. Methods have been devised. However, when the spring is strengthened, the critical speed becomes high, and resonance due to imbalance occurs at high speed, which is a problem.

In general, the energy of rotation is proportional to the square of the number of revolutions. Therefore, for example, the conventional support system of 3 Hz is
If a supporting system of 10 Hz or more that does not resonate with seismic waves is used, the rotational energy will be 10 times or more, and the effect of unbalanced vibration will increase, which is not preferable.

In the December 1968 issue of "Transactions of
`` Whirl Dynamics of a Rotor Partially Filled '' published in the ASME, Journal of Applied Mechanics
According to "With Liquid" pp. 676-682, an unstable region due to fluid vibration (see Fig. 13 in the above paper) occurs in a certain range where the ratio ω / ω ₀ between the rotational angular velocity ω and the test velocity ω ₀ exceeds 1. It is pointed out that it exists.

Recent research has revealed that this unstable region exists over a fairly wide range, and if the spring 6 is strengthened, it enters this unstable region.
It often causes unstable vibration.

On the other hand, a method of increasing the damping force by a damper is also described in the above-mentioned Japanese Patent Laid-Open No. 4-247251, which states that there is an optimum value in terms of the rotation characteristics at normal times, When a damper that is strong enough to prevent resonance with seismic force is used, the bearing load becomes excessive and the bearing life is shortened.

An attempt to reduce the bearing load during normal operation by detecting seismic waves and strengthening the damping force has been made, for example, in Japanese Patent Laid-Open No. 4-118064 or Japanese Patent Laid-Open No. 4-2818.
No. 70 publication.

For example, the main body of the separation container is hung vertically on a frame equipped with an earthquake detection device, a bearing housing is provided on the bearing base of the frame, and a rotary shaft is passed through the frame to the inside of the main body of the separation container. It is cantilevered and has a rotatable shaft,
A separation container is attached to the rotating shaft, and a damping spring and a magnetic fluid damper are provided between the bearing stand and the bearing housing. An electromagnet is connected to the magnetic fluid damper and the earthquake detection device and an earthquake occurs. It is provided so that it may be energized at times.

In this example, only when a large external force is applied during an earthquake, the electromagnet is energized and excited based on a signal from the earthquake detection device to excite the magnetic fluid of the magnetic fluid damper to provide a damping function. Not only can it be strengthened and vibration-damped, but it also has the outstanding effects of significantly extending the life of the rolling bearing, reducing the replacement of the rolling bearing, and improving the reliability and safety of the rolling bearing. I have.

However, in this case, since the seismic detection device and the magnetic fluid damper are used, the system is complicated and expensive, and if the seismic detection device should fail, it will not operate in the event of a power failure and is reliable. There is a problem with sex.

The present invention has been made to solve the above problems, and an object thereof is to provide a centrifugal sedimentation type clarifier having a simple structure, high reliability, and excellent earthquake resistance and maintainability. To do.

[0030]

According to the present invention, a motor mount provided on a casing, a motor drive unit attached to the motor mount, and a liquid to be treated contained in the casing and subjected to centrifugal separation. A separating cylinder, a drive shaft that is hung from above and that is flexible connected to the output side of the motor drive device, and a supporting device that supports the drive shaft so that it can rotate like a pendulum. A spring element that provides a restoring force between the drive shaft and the motor mount, and a shock absorber that is provided between the drive shaft and the motor mount and that provides a damping element that provides a damping force by combining a hydraulic damper and a rubber damper in series. , A steady rest attached with a gap between the drive shaft and the fixing member, and supplying the liquid to be treated into the separation cylinder A liquid supply device that is characterized by providing a device for discharging the clarified liquid.

Further, according to a second aspect of the present invention, there is provided a steady rest in which a rolling bearing is provided on the drive shaft side between the drive shaft and the drive shaft through hole so as to have a clearance. Further, according to the present invention, as described in claim 3, a ring-shaped steady rest whose surface is solid-lubricated is contacted between the drive shaft and the fixing member with an amplitude larger than that of the steady rest of the rolling bearing. It is provided with.

[0032]

In the clarifier of the present invention, the separating cylinder is suspended by a drive shaft so as to be rotatable in a pendulum shape (for example, the primary critical speed of the rotating system is 5 Hz or less, the secondary critical speed is 120 rpm of the rated speed). %), A simple structure in which a drive shaft is provided with a shock absorber in which a hydraulic damper and a rubber damper are combined in series, and it is possible to reduce the amplitude during an earthquake and reduce the bearing load during normal operation.

Further, by providing a rolling bearing on the drive shaft side with a gap between the drive shaft and the drive shaft through hole of the shield floor, the displacement of the drive shaft and the separating cylinder can be prevented against a larger earthquake. It can be limited, and damage due to contact between the rotating body and the stationary body can be prevented. In particular, by using the rolling bearing as the steady rest, the tangential load when the steady rest comes into contact is canceled out, and whirling force is hardly generated, so that it is safer.

Further, since the rolling bearing is provided on the drive shaft side, the diameter of the rolling bearing itself can be reduced, and the steady rest of this portion can be made compact and easy to dispose, and the rotational inertia mass of the rolling bearing can be reduced. Since the size becomes smaller, the responsiveness of the rolling bearing when the steady rest comes into contact is improved, and the whirling force can be further reduced.

As a backup, the seismic resistance is further enhanced by providing a solid-lubricated ring-shaped steady rest so as to operate at a larger amplitude. Particularly in the case of a clarifier that handles hazardous substances such as harmful substances and radioactive substances, a steady rest consisting of a rolling bearing is installed in an accessible part such as the outside of the casing, and a ring-shaped steady rest is located inside the casing near the center of gravity. It is possible to improve the maintainability by installing it in the.

Further, by providing the rolling bearing on the drive shaft side, it becomes possible to remove the motor drive device together with maintenance, and further improve the maintainability.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a clarifier according to the present invention will be described with reference to the drawings. FIG. 1 shows a first embodiment in which the present invention is applied to a centrifugal sedimentation type clarifier. This clarifier handles radioactive materials such as nuclear fuel reprocessing facilities and nuclear power plants.

There is a cylindrical casing 20 installed below the shielding floor 21, and a motor mount 22 is installed above the shielding floor 21 via a base plate 23. Casing 20
A cylindrical separating cylinder 24 is rotatably accommodated therein.

The separating cylinder 24 is made of titanium or titanium alloy (T
While made of i-6A1-4V alloy), upper and lower plates 25 and 26 are attached to the upper and lower ends of the separation cylinder 24, respectively. A plurality of, for example, four baffle plates 27 extending in the axial direction are provided in the separating cylinder 24 at equal pitch intervals in the circumferential direction. The baffle plate 27 may be, for example, six or eight. A torus-shaped liquid reservoir 28 is recessed in the lower end plate 26.

On the other hand, the central boss portion 29 of the lower end plate 26 is supported by the drive shaft 30. The drive shaft 30 is integrally joined to the upper shaft 32 via a flange shaft coupling 31, and the shaft 30 and the separating cylinder 24 form a rotary system.

The upper shaft 32 has a flexible joint 35 attached to an output shaft 34 of a motor drive device 33 such as an electric motor or a hydraulic motor.
Are connected via. The separation cylinder 24 is driven to rotate by the drive of the motor driving device 33.

The rotating system is an upper bearing such as an upper angular bearing.
The thrust load is supported by 36, and the radial load is supported by both the upper bearing 36 and the lower bearing 37. Bearings 36, 37
Is housed in a cylindrical (sleeve) -shaped bearing housing 38. The bearing housing 38 is supported by the motor mount 22 via a spherical bearing 39, and the spherical bearing 39 can freely vibrate like a pendulum about the center O. It is like this.

On the other hand, the bearing housing 38 is elastically supported by the motor pedestal 22 via the coil spring 40, and the motor pedestal is tightened by nuts via the shock absorber 43 in which the oil damper 41 and the rubber damper 42 are connected in series. Connected to 22.

The spring constant of the coil spring 40 is selected so that the primary critical speed of the entire rotary system (drive shaft 30 and separation cylinder 24) is 5 Hz or less, preferably 3 Hz or less. Further, the shock absorber 43 includes an oil damper 41 and a rubber damper 42.
Select a combination such that the damping characteristics in the combination of and have a maximum peak at a frequency near the primary critical speed of the entire rotary system, and the damping coefficient ratio at that peak value is
It is desirable to select 0.2 to 0.6 and the value at the rated speed to be 0.1 to 0.3.

A liquid supply nozzle 44 as a liquid supply device, a cake cleaning spray pipe 45 and a cake cleaning spray 46 as a cleaning spray device are provided in the separation cylinder 24, and a liquid reservoir on the lower end plate 26 is provided. A plurality of sludge suction tubes 47 as liquid sucking devices are provided in 28. A stirring blade 48 is attached to the tip of the suction tube 47.

The sludge suction pipe 47 moves upward in the separation cylinder 24 and the guide cylinder 49, is bent outward in the radial direction from above the separation cylinder 24, and protrudes outside the casing 20. It is bent into a mold, and the other end is guided to an airtight sludge collecting can 50 provided at a level lower than the sump 28. The inside of the recovery can 50 is decompressed by the decompression pipe 51 by a vacuum pump or the like (not shown).

In the solid-liquid separation device as shown in FIG. 1, for example, the effective rotation radius r ₂ of the separation cylinder 24 is 0.45 m and the rotational angular velocity ω is 21.
When set to 0 rad / s, the peripheral speed of the separation cylinder 24 is 95 m / sec.
It will be about.

An upper steady rest 53 formed of a rolling bearing is installed on the upper shaft 32 at the upper end of a through hole 52 through which the drive shaft 30 of the shield floor 21 penetrates. The upper steady rest 53 is mounted between the flange shaft coupling 31 and the shaft 32 with an upper steady rest sleeve 68 and a gap g ₁ . The inner surface of the upper steady rest sleeve 68 is subjected to a galling prevention treatment, for example, a surface treatment such as a gold coating layer 69.

A sleeve 54 is attached to the lower end of the drive shaft 30 in the vicinity of the center of gravity of the rotating system, and a lower steady rest 55 is installed at a portion facing the sleeve 54 with a gap g ₂ between the sleeve 54 and the sleeve 54. The lower steady rest 55 is fixed to the shield floor 21 via the guide tube 49.

The lower steady rest 55 is formed by applying solid lubrication to the inner surface of the metal ring. In this embodiment, radiation resistance,
Considering chemical resistance, the inner surface of the stainless steel ring is gold coated. In the separation cylinder 24, a liquid supply nozzle 56 is provided penetrating the side surface of the casing 20,
Further, a clarified liquid outlet nozzle 57 is connected to the side surface of the casing 20.

FIG. 2 shows the structure of the shock absorber 43 of this embodiment. The oil damper 41 is provided in a cylindrical cylinder 58 so that a piston 60 having an orifice hole 59 and a piston rod 61 can move left and right. A case 62 is provided on the outer side of the cylinder 58 with a certain space between the piston rod 61 and
A seal 63 is provided between the case and the case 62. The case 62 is filled with oil. When the piston 60 moves in the cylinder 58, a damping force is generally obtained due to the viscosity of oil.

Rubber blocks 64 and 65 are attached to both ends of the oil damper 41, and are connected to the motor mount 22 and the bearing housing 38 via the rubber blocks 64 and 65, respectively. In this example, a rubber having a Shore hardness of 70 is selected,
The frequency characteristic shown in FIG. 5 was obtained.

FIG. 3 is an enlarged view of the vicinity of the upper steady rest 53. That is, in FIG. 3, inside the through hole 52 of the shield floor 21, the rolling bearing 66 is provided on the upper shaft 32 side and the upper steady rest sleeve 68 is provided at a portion facing the rolling bearing 66. The rolling bearing 66 is coated with lead for non-lubrication use, and the surface of the upper steady rest sleeve 68 is coated with gold to prevent galling.

FIG. 4 is an enlarged view of the lower steady rest 55. A gold coating layer 67 is applied to a portion of the lower steady rest 55 that comes into contact with the sleeve 54. Further, since the drive shaft is tilted about the spherical bearing located above, the inner surface of the gold coating layer is tilted slightly inward so that the sleeve 54 hits uniformly. When the drive shaft 30 vibrates,
First of all, the dimensions are such that the gap of g ₂ comes into contact.

FIG. 6 shows an example of setting the spring constant of the coil spring 40 used in the solid-liquid separation device shown in FIG. Regardless of the predominant frequency of the earthquake, select the optimum spring constant in terms of rotation characteristics.

The graph of FIG. 6 shows a coil spring on the horizontal axis.
The spring constant of 40 and the natural frequency of the rotating system are taken on the vertical axis, and the curves in the figure show the degree of primary and secondary risks obtained by the transfer matrix method.

In this embodiment, the primary dangerous speed is selected to be 3 Hz or less. In this case, the coil spring 40
The spring constant k may be about 7 × 10 ² kgf / mm. On the other hand, since the rotation speed of the separating cylinder 24 is about 34 Hz, 34 × 1.2 =
The spring constant at which the secondary critical speed is 40.8 Hz or higher is approximately 10 ² k.
It will be gf / mm. Therefore, the optimum value in this period may be selected.

Next, the solid-liquid separation action of this solid-liquid separation device will be described. The solid-liquid separation device starts operation by driving a motor drive device 33, and the motor drive causes the separation cylinder 24 to rotate at a predetermined rotation speed, for example, a rotation angular velocity ω = 630 rad /
It rises to about sec. The effective rotation radius (inner radius) r _{2 of the} separating cylinder 24 is, for example, 0.2 m.

When the operation of the solid-liquid separation device is started, the liquid to be treated is supplied to the lower part inside the separation cylinder 24 by the liquid supply nozzle 56. The supplied liquid to be treated is retained on the inner surface of the separation cylinder 24 by the centrifugal force accompanying the rotation of the separation cylinder 24 and the assistance of the baffle plate 27.

The liquid to be treated held in the separation cylinder 24 is subjected to the action of rotational centrifugal force, and while flowing through the separation cylinder 24, solids having a large specific gravity are sedimented and separated on the inner wall surface of the separation cylinder 24. And it becomes a cake. The clear liquid from which solids have been separated is the top plate
It overflows through the opening of 25, passes between the casing 20 and the separation cylinder 24, and is discharged from the clarified liquid outlet nozzle 57 to the outside.

When the solid-liquid separation treatment of a certain amount of the liquid to be treated is performed, the amount of cake attached to the inner surface of the separation cylinder 24 increases, so the solid-liquid separation operation is stopped and the cake is discharged.
When a certain amount of the liquid to be treated is processed and the cake is accumulated in the separation cylinder 24, the rotation is slowly stopped first.

The cake remains attached to the inner wall surface of the separation cylinder 24, and the supernatant liquid drops into the liquid reservoir 28. This supernatant liquid is sucked up by one of a plurality of sludge suction tubes 47 and collected in a sludge collecting can 50.

At this time, the sludge recovery can 50 is decompressed from the decompression pipe 51 by a vacuum pump or the like, so that the sludge suction pipe 47 acts as a siphon to collect the liquid.
It can be transferred to 50 smoothly. In the collected liquid,
Since the solid content (and the active ingredient) is contained, it is returned to the liquid tank to be treated by a return line not shown.

Next, while the separating cylinder 24 is slowly rotated by the motor drive device 33, high-pressure water is sprayed from the cake cleaning spray 46 toward the inner surface of the separating cylinder 24. As a result, the cake is peeled off and falls into the liquid reservoir 28 together with the wash water. When the separating cylinder 24 makes one to two revolutions and all the cakes have fallen, the rotation of the motor driving device 33 is increased by 10 to 40 rpm.

Since the stirring blade 48 provided in the liquid reservoir 28 is fixed to the casing 20, the liquid rotates and is stirred. By this stirring, the liquid to be treated contained in the particles of the cake is washed.

Next, the rotation of the separation cylinder 24 by the motor drive device 33 is increased to the rated high speed rotation. At this time, sump 28
Wash water and solids inside are slopes that form the sides of the sump
After going up 28a, centrifugal sedimentation separation is performed again in the separation cylinder 24. This operation is performed for a sufficient period of time A (usually 5 to 10
Min) to form a cake on the inner wall of the separating cylinder 24.

Next, the rotation of the separation cylinder 24 is stopped, the washing water dropped in the liquid reservoir 28 is sucked up by the sludge suction pipe 47, and returned to the liquid tank to be treated by the return line. Then, the separation cylinder 24
While slowly rotating the cake, the cake is dropped into the liquid reservoir 28 by the cake washing spray 46.

Almost no component of the liquid to be treated remains in this cake. Therefore, while rotating at 10 to 40 rpm, while stirring, another sludge suction pipe 47 sucks up the solid component in the form of slurry and collects it in the sludge collecting can 50.

Next, the operation when an imbalance occurs will be described. When an imbalance occurs, the spring constant is small (soft), and the shock absorber 43 is provided with rubber blocks 64 and 65 as shown in FIG. Since the damping force in the frequency range is not too strong and is at an appropriate level, the unbalanced load applied to the bearing can be reduced,
Lifespan is extended.

Further, the oil damper 41 is used for a comparatively large vibration when passing through the first dangerous speed at the time of acceleration / deceleration.
As can be seen in FIG. 5, due to the action of, the vibration has an almost peak frequency of the damping force, so that the vibration can be effectively suppressed.

On the other hand, the action during an earthquake will be described. For the predominant frequency of an earthquake (in this case, about 5 Hz),
Since the damping force is larger than that in FIG. 5, vibration of the rotating body due to an earthquake can be suppressed to a small level, and contact and damage to the stationary body can be prevented during a normal earthquake. In this case, operation is possible without any problems even after the earthquake.

In addition, for a larger earthquake (for example, a large earthquake that may occur during the life of the plant equipment, which is about the standard earthquake ground motion S _{1 of the} strongest earthquake for design shown in the JEAG4601 Electrical Engineering Guideline for Seismic Design of Nuclear Power Plants) On the other hand, suppressing the amplitude by the shock absorber 43 is not sufficient. In this case, since the amplitude is limited by the upper steady rest 53, it is possible to prevent contact and damage of the rotating body.

At this time, since the upper steady rest 53 uses the rolling bearing, the rotational force at the time of contact is released and the whirling does not occur. Also, since the diameter is small, it is supposed to hit the drive shaft 30 with a low peripheral speed,
Safer.

Further, since the ball surface of the rolling bearing 66 is coated with lead, the function of smoothly rotating can be maintained for a long period of time without using a lubricant such as grease. Further, since the upper steady rest 53 is installed on the upper shaft 32 of the motor drive device 33 above the shield floor 21,
It is extremely easy to inspect and replace after an earthquake and has excellent maintainability.

Since there is almost no possibility of occurrence of an earthquake of S ₁ earthquake or more (for example, the design limit earthquake S ₂ described in JEAG4601), the structure described above usually has sufficient seismic resistance. Due to the importance of handling radioactive substances, a lower steady rest 55 is further provided.

The gap g ₂ of the lower steady rest 55 is set so that the drive shaft 30 is deformed by the stronger seismic force after the upper steady rest 53 comes into contact with the gap g ₂ , and the contact is made until the S ₁ earthquake. In the case of the earthquake, there is no need for inspection or replacement.

This is extremely effective in maintenance when handling high radioactivity because the dose of the lower steady rest 55 is high. And, in case of an earthquake larger than S ₁ , it acts as a backup and can prevent damage to the equipment.

Further, since the surface is coated with the gold coating layer 67, there is a lubricating action at the time of contact and it is possible to prevent whirling due to the rotational force. Since gold has excellent radiation resistance and corrosion resistance, maintenance is unnecessary for a long period of time.

FIG. 7 shows the results of a seismic resistance test performed by applying a seismic wave on a vibration table using a test apparatus. The horizontal axis is the upper steady rest gap g ₁ , and the vertical axis is the seismic force applied. The black circles represent the upper steady rest contact points, and the white circles represent the lower steady rest contact points. The bottom steady rest gap was 10 mm. From this test result, it is clear that a gap of g ₁ = 1.7 mm or less should be selected as the range that does not contact the lower steady rest in the S ₁ earthquake.

[0080]

According to the present invention, the separating cylinder is suspended by the drive shaft so as to be freely rotatable like a pendulum,
Moreover, by providing the shock absorber in which the oil damper and the rubber damper are combined, the bearing load during normal operation can be reduced and the life can be extended, and the displacement during an earthquake can be suppressed and the earthquake resistance can be improved.

Further, by providing an upper steady rest on the accessible portion of the upper surface of the shield floor, it is possible to prevent direct contact between the stationary body and the rotating body and whirling at the time of an earthquake, improve seismic resistance, and perform post-earthquake inspection. , Exchange becomes easy. Furthermore, by providing a bottom rest near the center of gravity of the rotating body, it becomes possible to protect the equipment and improve safety in the unlikely event of a large earthquake.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a first embodiment of a clarifier according to the present invention.

FIG. 2 is a vertical sectional view showing a shock absorber in FIG.

FIG. 3 is a vertical cross-sectional view showing an upper steady rest in FIG.

FIG. 4 is a vertical cross-sectional view showing the lower steady rest in FIG.

FIG. 5 is a graph showing the characteristics of the shock absorber in FIG.

FIG. 6 is a graph for obtaining a spring constant of a spring in the fining machine shown in FIG.

FIG. 7 is a graph showing a vibration test result of the fining machine shown in FIG. 1 and a steady-state clearance.

FIG. 8 is a vertical sectional view showing a conventional fining machine.

9 is a sectional view taken along line XX of FIG.

10 is a vertical cross-sectional view showing the operation of FIG.

11 is a longitudinal sectional view showing the operation advanced from FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Casing, 2 ... Separation cylinder, 3 ... Upper end plate, 4 ... Lower end plate, 5 ... Support leg, 6 ... Spring, 7 ... Rib, 8 ... Drive shaft, 9 ... Motor drive device, 10 ... Bearing housing, 11 ... Bearing, 12 ... Liquid supply nozzle, 13 ... Exit nozzle, 14 ...
Scraping blade, 15 ... Moving device, 16 ... Cake discharge port, 17 ... Washing liquid nozzle, 18 ... Mounting member, 19 ... Cake, 20 ... Casing, 21 ... Shield floor, 22 ... Motor mount, 23 ... Base plate, 24 …
Separation cylinder, 25 ... Top plate, 26 ... Bottom plate, 27 ... Baffle plate, 28
... Liquid reservoir, 29 ... Boss part, 30 ... Drive shaft, 31 ... Flange shaft coupling, 32 ... Upper shaft, 33 ... Motor drive device, 34 ... Output shaft, 35 ... Flexible joint, 36 ... Upper bearing, 37 ... Lower bearing , 38 ... Bearing housing, 39 ... Spherical bearing, 40 ... Coil spring, 41 ... Oil damper, 42 ... Rubber damper, 43 ... Buffer device, 44 ... Liquid supply nozzle, 45 ... Cake cleaning spray pipe, 46 ... Cake cleaning spray, 47 … Sludge suction pipe, 48… stirring blade, 49… guide cylinder, 50… sludge collecting can, 51… pressure reducing pipe, 52… through hole, 53… upper steady rest, 54…
Sleeve, 55 ... Lower steady rest, 56 ... Liquid supply nozzle, 57 ... Clarifying liquid outlet nozzle, 58 ... Cylindrical cylinder, 59 ... Orifice hole, 60 ... Piston, 61 ... Piston rod, 62 ... Case,
63 ... Seal, 64,65 ... Rubber block, 66 ... Rolling bearing, 67 ... Gold coating layer, 68 ... Top steady sleeve, 69 ... Gold coating layer.

Claims (3)

[Claims] 1. A motor pedestal provided on a casing, a motor drive device mounted on the motor pedestal, a separation cylinder housed in the casing for centrifuging a liquid to be treated, and a separation cylinder. While hanging from above,
A drive shaft flexibly connected to the outlet side of the motor drive device, a support device that supports the drive shaft so that it can rotate like a pendulum, and a spring that applies a restoring force between the drive shaft and the motor mount. There is a gap between an element, a shock absorber that combines a hydraulic damper and a rubber damper in series to provide a damping element that gives a damping force, and a drive shaft through hole of a shield floor that fixes the drive shaft and the motor mount. And a steady rest formed of a rolling bearing provided on the drive shaft side. 2. A steady rest formed of a rolling bearing on the drive shaft side and a ring-like steady rest are provided between the drive shaft and the drive shaft through hole of the shield floor with a gap therebetween. The clarifier according to claim 1, which is characterized in that 3. The steady rest comprising the rolling bearing is characterized in that a detachable sleeve formed by plating or coating a soft metal film on the surface of the through hole side above the through hole is provided. The clarifier according to claim 1, wherein