JPH0729070B2 - Centrifuge filter cleaning method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for cleaning a filter provided on the inner circumference of a basket of a centrifuge.

[Prior Art] As shown in FIG. 3, in a centrifuge in which a permeation hole 3e is provided in the peripheral wall of the basket 3 and a liquid component is permeated through the permeation hole 3e, a filter 7 is provided on the inner periphery of the basket 3. It is arranged so that the liquid is filtered through the filter. Generally, the basket 1 is arranged in a casing, and a liquid supply pipe, a solid matter scraping device, etc. are attached to the casing.

In this type of centrifuge, the filter 7 needs to be washed after a certain amount of the stock solution is treated because the solid particles C clog the filter 7.

Conventionally, the solid material formed on the inner circumference of the basket is scraped by a scraping device, and then the cleaning liquid is sprayed from the liquid supply pipe to the inner circumference of the basket while the basket is rotated to clean the filter. It was

[Problems to be Solved by the Invention] As described above, in the method of cleaning the filter by spraying the cleaning liquid from the liquid supply pipe to the inner circumference of the basket, the filter is pressed by the pressure of the cleaning liquid acting on the outer side in the radial direction of the basket. Since the solid particles C are caught in the eyes of the filter 7, it is difficult to completely clean the filter.

In particular, since the casing is sealed and the centrifugal separator that processes the undiluted solution in a sealed atmosphere cannot visually check the state of the filter, the cleaning is performed for a fixed time set by a timer. If the particles of the filter become caught in the fiber or lattice of the filter, the particles cannot be removed from the filter regardless of how long the cleaning time is set, so that the filter is not completely cleaned and the next process is started. It will be. If the stock solution to be processed subsequently is from the same lot as the previous solution, there is no problem even if solids remain in the filter, but if the lots are different or the stock solution itself is different, However, the solid matter remaining in the filter adversely affects the treatment of a new stock solution.

It is an object of the present invention to propose a filter cleaning method for a centrifuge, which is capable of obtaining better cleaning results than ever before.

MEANS FOR SOLVING THE PROBLEM The present invention relates to a casing, a basket arranged in the casing, a filter arranged on the inner circumference of the basket, and a solid scraping off solid matter formed on the inner circumference of the basket. A method of cleaning a filter of a centrifuge, which comprises a scraping device and allows liquid to pass through the filter and a permeation hole provided in a peripheral wall of the basket.

In the cleaning method of the present invention, while the cleaning liquid is injected into the casing and the basket is filled with the cleaning liquid, rotation of the casing and rapid deceleration or sudden stop are alternately performed, or rotation of the basket in one direction is performed. It is characterized in that a rapid change occurs in the rotation of the basket by alternately performing the rotation in the other direction.

When rotating the basket in the cleaning liquid, it is preferable to place an obstacle in the liquid flow generated in the casing to generate a turbulent flow of the cleaning liquid in the casing.

As the obstacle, the scraping blade of the solid scraping device can be used, and the blade is attached to the inner surface of the casing,
The blade can also be used as the obstacle.

[Operation] The cleaning liquid is injected into the casing as described above, and while the basket is filled with the cleaning liquid, the basket is alternately rotated and suddenly decelerated or suddenly stopped, or the basket is rotated in one direction. When the cleaning liquid and the rotation in the other direction are alternately performed, a cleaning liquid flow that changes intricately along the circumferential direction of the basket is generated and the cleaning liquid flow is applied to the solid particles attached to the filter. Since it is possible to reduce the probability that solid particles will be clogged in the filter, compared to the case of using the conventional cleaning method in which the cleaning liquid is sprayed from the liquid supply pipe to the radial outside of the basket. The amount of solids remaining on the filter can be reduced to enhance the cleaning effect.

Further, when an obstacle is arranged in the flow of the cleaning liquid to cause a turbulent flow of the cleaning liquid, the flow of the cleaning liquid that hits the particles of the solid can be further complicated to enhance the cleaning effect.

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

FIG. 1 shows an example of the configuration of an apparatus for carrying out the method of the present invention. In FIG. 1, 1 is a cylindrical casing supported by supporting legs 2 equipped with a vibration isolator, and 3 is a cylindrical peripheral wall. A basket having a portion 3a, a bottom wall portion 3b, and an annular end wall 3c. This basket 3 has a boss portion 3d at the center of its bottom portion 3b, and a rotary shaft 4 attached to the boss portion 3d.
Are supported by a bearing device 5 provided at the bottom of the casing 1. The lower end of the rotary shaft 4 is connected to a rotary drive source 6 such as a hydraulic motor, and the basket 3 is connected by the drive source.
Is driven to rotate. A large number of through holes 3e are formed in the peripheral wall portion 3a of the basket 3, and an annular groove portion 3f surrounding the boss 3d is provided in the bottom portion 3b. Outer peripheral wall of groove 3f
3f1 is provided with a slope that gradually increases toward the outside in the radial direction toward the top. The filter 7 straddles the inner circumference of the peripheral wall 3a of the basket, the inner surface of the end wall 3c, and the inner surface of the bottom 3b.
Is provided.

Reference numeral 8 is a liquid supply pipe, 9 is a solid material discharge pipe, and these pipes are inserted into the basket through the cover plate 1a of the casing 1. The liquid supply pipe 8 has a large number of ejection holes 8a on its side surface, and supplies the stock solution or the cleaning solution toward the peripheral wall portion of the basket 1 from these ejection holes. The liquid supply pipe may be open at its lower end only.

The solid matter discharge pipe 9 is made of a straight pipe, and the opening at the lower end thereof faces the bottom surface of the groove 3f at the bottom of the basket with a predetermined gap. The solid material discharge pipe is connected to a suction device (not shown).

10 is a solid matter scraping device, which is a casing 1
The lid plate 1a is provided with a rotary shaft 10a which is rotatably and slidably penetrated by an airtight holding structure, and a scraping blade 10b attached to the rotary shaft.

Although not shown, on the lid plate 1a of the casing 1, an elevating mechanism for elevating the rotating shaft 10a of the scraping device and the rotating shaft 1a.
A scraping device drive mechanism including a rotation mechanism for rotating 0a is provided. An electric motor, for example, is used as a drive source of the scraping device drive mechanism.

A valve 12 is connected to the lid plate 1a of the casing 1 via a pipe 11, and the valve 12 is connected to a cleaning liquid supply source (not shown). Also, a drain port provided at the bottom of the casing 1.
A valve 14 is connected to 1b via a pipe 13, and by closing the valve 14, liquid can be stored in the casing 1. A plurality of blades 15 are attached to the inner periphery of the peripheral wall portion 1c of the casing 1 at appropriate intervals in the circumferential direction.

When the stock solution is processed by the above centrifuge, the rotation shaft 10a of the scraping device 10 is pulled up and the scraping blade 10b is retracted to the rotation shaft side of the basket. Then, the rotary drive source 6 is activated to rotate the basket 3 at high speed, and the liquid supply pipe 8
The stock solution is supplied into the basket 3 from. After the supply of the undiluted solution is completed, the basket is rotated at a high speed for a certain period of time to perform the deliquoring process. After the liquid removing process is completed, the cleaning liquid is supplied from the liquid supply pipe 8 while maintaining the rotation of the basket to wash the solid matter (cake) formed on the inner circumference of the basket. Then, the supply of the cleaning liquid is stopped, and the basket 3
Drain the liquid by rotating. After the drainage is completed, the basket is braked to reduce the rotation speed of the basket to the scraping rotation speed.

After the rotation speed of the basket has decreased to the scraping speed, the rotating shaft 10a is rotated to cause the scraping blade 10b to enter the solid material layer on the inner circumference of the basket, thereby scraping the solid material and removing the bottom portion of the basket. To the side. Scraping of solid matter is advanced while gradually rotating the rotating shaft 10a. In this process, a suction device (not shown) is operated to suck the solid matter in the groove 3f through the solid matter discharge pipe 9 and discharge the solid matter to the outside through the solid matter discharge pipe. This solid material is transported by air and sent to the next step.

After the discharge of the solid matter is completed, the solid matter scraping device 10 is returned to the original position, the undiluted solution is supplied again, and the above steps are repeated.

When a predetermined amount of the stock solution is treated, the filter 7 is washed by the method of the present invention. When the filter 7 is washed, the solid matter is discharged, the valve 14 is closed and the valve 12 is opened, and the washing liquid is injected into the casing 1 through the valve 12. Water or hot water is usually used as the cleaning liquid.
As shown in FIG. 2, the casing 1 is filled with the cleaning liquid 16, and the basket 3 is rotated at a high speed while the inside of the basket is filled with the cleaning liquid 16. When the basket is rotated, the cleaning liquid cannot first follow the basket, so that a relative displacement in the circumferential direction occurs between the basket and the cleaning liquid, and the cleaning liquid hits the particles of the solid matter adhering to the filter 7 from the circumferential direction of the basket. . This causes particles of solids to separate from the fibers or grid of the filter. When a certain time has elapsed after rotating the basket, the cleaning liquid 16 is rotated at the same speed as the basket, and the cleaning effect is weakened. In order to enhance the cleaning effect, it is necessary to lengthen the time during which the relative displacement between the basket and the cleaning liquid occurs. Therefore, in the present invention, rotation of the basket in one direction and sudden deceleration or sudden stop are alternately performed, or
Alternatively, rotation of the basket in one direction and rotation in the other direction are alternately performed. In this way, not only can the time during which the relative displacement between the basket and the cleaning liquid occurs is increased, but also a complicated change in the flow of the cleaning liquid can occur, so that solid particles can be removed from the filter. The probability of clogging can be reduced and the cleaning effect can be enhanced.

In order to further enhance the cleaning effect, it is preferable to place an obstacle in the flow of the cleaning liquid to cause turbulence. Generally, a scraping device, a liquid supply pipe, and the like are provided inside the basket, and these act as obstacles, so that a turbulent flow of the cleaning liquid can be generated. In order to enhance the cleaning effect due to this turbulent flow, it is preferable to orient the scraping blade 10b in a direction having an angle with respect to the inner peripheral surface of the basket 3 and effectively utilize the scraping blade as an obstacle. In this case, it is preferable to move the rotating shaft 10 of the scraping device up and down so that the cleaning effect due to the turbulent flow is evenly distributed over the entire area of the basket in the axial direction. Further, as shown in the figure, if the blades 15 are attached to the inner circumference of the casing 1, a turbulent flow of the cleaning liquid can be generated and the cleaning effect can be enhanced.

Sudden acceleration / deceleration of the basket, switching of the rotation direction, and the like when cleaning the filter may be automatically performed by a sequencer according to a program created in advance, or may be performed by a driver's switch operation. In any case, the time for cleaning the filter is set to be long enough to separate the solid particles from the filter.

After the cleaning of the filter 7 is completed, the basket is stopped, the valve 14 is opened, and the cleaning liquid in the casing 1 is discharged.

If the amount of solids contained in the discharged cleaning liquid is large to some extent, the solids in the cleaning liquid may adhere to the filter again. In such a case, in order to complete the cleaning of the filter, it is preferable that the valve 14 be closed and the same filter cleaning step as described above be performed again.

[Effects of the Invention] As described above, according to the present invention, rotation of the basket and rapid deceleration or sudden stop are repeated with the cleaning liquid injected into the casing and the basket filled with the cleaning liquid, or
Alternatively, by repeating the reversal of the rotation direction of the basket, a complicatedly changing flow of the cleaning liquid is generated along the circumferential direction of the basket, so that the flow of the cleaning liquid is applied to the particles of the solid matter attached to the filter. The probability of solid particles clogging the filter can be reduced, and it remains on the filter compared to the case of the conventional cleaning method in which the cleaning liquid was sprayed from the liquid supply pipe to the radial outside of the basket. The amount of solids can be reduced to enhance the cleaning effect.

Particularly, according to the invention described in claim 3, 4 or 5, since an obstacle is arranged in the flow of the cleaning liquid to generate a turbulent flow of the cleaning liquid, the flow of the cleaning liquid corresponding to the particles of the solid is further increased. There is an advantage that the cleaning effect can be further enhanced by making it complicated.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration example of a centrifugal separator to which the method of the present invention is applied, FIG. 2 is a cross-sectional view showing a state in which a filter is washed by the method of the present invention, and FIG. It is a principal part sectional view which showed the state where the filter was clogged when the conventional cleaning method was used. 1 ... Casing, 3 ... Basket, 3e ... Transmission hole,
4 ... Rotary shaft, 7 ... Filter, 8 ... Liquid supply pipe, 9
...... Solid material discharge pipe, 10 …… Solid material scraping device, 10b…
… Scraping blade, 15… feather.

Claims (5)

[Claims] 1. A casing, a basket arranged in the casing, a filter arranged on the inner circumference of the basket, and a solid matter scraping device for scraping off solid matters formed on the inner circumference of the basket. In the method of cleaning the filter of the centrifuge, which comprises allowing the liquid to pass through the filter and the permeation hole provided in the peripheral wall portion of the basket, the cleaning liquid is injected into the casing to wash the inside of the basket with the cleaning liquid. And cleaning the filter by alternately rotating the basket and suddenly decelerating or suddenly stopping it in the cleaning liquid in the casing. 2. A casing, a basket arranged in the casing, a filter arranged on the inner circumference of the basket, and a solid matter scraping device for scraping off solid matters formed on the inner circumference of the basket. In the method of cleaning the filter of the centrifuge, which comprises allowing the liquid to pass through the filter and the permeation hole provided in the peripheral wall portion of the basket, the cleaning liquid is injected into the casing to wash the inside of the basket with the cleaning liquid. And washing the filter by alternately rotating the basket in one direction and rotating it in the other direction in the cleaning liquid in the casing. 3. The centrifuge according to claim 1, wherein an obstacle is arranged in the cleaning liquid flow generated in the casing due to the rotation of the basket to generate a turbulent flow of the cleaning liquid in the casing. Separator filter cleaning method. 4. The filter cleaning method for a centrifuge according to claim 3, wherein a scraping blade of the solid scraping device is used as an obstacle for generating the turbulent flow. 5. The filter cleaning method for a centrifuge according to claim 3, wherein a blade is attached to the inner surface of the casing and the blade is used as the obstacle.