JPH0342060A - Washing method for filter in centrifugal separator - Google Patents

Abstract

PURPOSE:To obtain washing effect better than a conventional method by introducing washing liquid into a casing and rotating a basket in this washing liquid in the casing and washing a filter arranged to the inner circumference of the basket. CONSTITUTION:A basket 3 is arranged in a casing 1 and also a filter 7 is arranged to the inner circumference of the basket 3. Solid material formed in the inner circumference of this basket 3 is scraped by a scraper 10. Further, a liquid is allowed to permeate through the filter 7 and the permeation holes 3e provided to the circumferential wall part of the basket 3. Washing liquid is introduced into the casing 1 and the basket 3 is rotated in this washing liquid in the casing 1 to wash the filter 7. As a result, the washing result better than a conventional method is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for cleaning a filter provided on the inner periphery of a basket of a centrifuge.

[Prior Art] As shown in FIG.
In a centrifugal separator in which liquid is permeated through the permeation hole 3e, a filter 7 is disposed on the inner periphery of the basket 3, and the liquid is filtered through the filter. Generally, the basket 1 is arranged within a casing,
A liquid supply pipe, a solid matter scraping device, etc. are attached to the casing.

In this type of centrifugal separator, the filter 7 is clogged with solid particles C, so it is necessary to wash the filter after processing a certain amount of the stock solution.

Conventionally, after the solid matter formed on the inner periphery of the basket is scraped off by a scraping device, the filter is cleaned by spraying cleaning liquid onto the inner periphery of the basket from a liquid supply pipe while the basket is rotating. Ta.

[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 onto the inner periphery of the basket, the filter is pushed by the pressure of the cleaning liquid acting on the radially outer side of the basket. Since the solid particles C were caught in the holes of the filter 7, it was difficult to completely clean the filter.

In particular, in centrifugal separators whose casings are sealed and the undiluted solution is processed in a sealed atmosphere, the condition of the filters cannot be visually checked, so washing is carried out for a fixed period of time set by a timer, but solids If particles become stuck in the fibers or grid of the filter, they cannot be removed from the filter no matter how long the cleaning time is set, so in the end, the filter is left incompletely cleaned and the next process is started. It turns out. If the stock solution to be processed next is from the same lot as the stock solution processed last time, there is no problem even if solid matter remains in the filter, but if the loft is different or the stock solution itself is different, , solids remaining in the filter will adversely affect the processing of new stock solution.

SUMMARY OF THE INVENTION An object of the present invention is to propose a filter cleaning method for a centrifugal separator that can obtain better cleaning results than conventional methods.

[Means for Solving the Problems] The present invention includes a casing, a basket disposed in the casing, a filter disposed on the inner periphery of the basket, and a solid filter for scraping solid matter formed on the inner periphery of the basket. This is a method for cleaning the filter of a centrifugal separator, which includes a material scraping device and allows liquid to pass through the filter and a permeation hole provided in the peripheral wall of the basket.

The invention is basically characterized in that a cleaning liquid is injected into the casing and the basket is rotated in the cleaning liquid inside the casing.

In the present invention, when rotating the basket in the cleaning liquid, it is preferable to vary the rotation of the basket rather than simply rotating the basket. For example, it is preferable to alternately rotate the basket and suddenly decelerate or stop the basket.

Further, the rotation of the basket in one direction and the rotation in the other direction may be performed alternately.

Further, when rotating the basket in the cleaning liquid, it is preferable to arrange obstacles in the liquid flow generated in the casing to create a turbulent flow of the cleaning liquid in the casing.

As the above-mentioned obstacle, a scraping blade of a solid material scraping device can be used, and a blade is attached to the inner surface of the casing,
The blades can also be used as the obstacles.

[Function] When the cleaning liquid is injected into the casing and the basket is rotated in the cleaning liquid as described above, the flow of the cleaning liquid generated along the circumferential direction of the basket can be applied to the solid particles attached to the filter. This reduces the probability that solid particles will clog the filter, compared to the conventional cleaning method in which cleaning liquid is sprayed radially outward from the basket from the liquid supply pipe. It is possible to reduce the amount of solid matter remaining in the washing machine and improve the cleaning effect.

In particular, by repeating acceleration and deceleration of the basket, repeating rotation and sudden stop of the basket, or reversing the direction of rotation of the basket, the flow of the cleaning liquid that hits the solid particles can be changed in a complex manner, which improves the cleaning effect. can be increased.

In addition, if an obstacle is placed in the flow of the cleaning liquid to create a turbulent flow of the cleaning liquid, the flow of the cleaning liquid that hits the solid particles can be further complicated and the cleaning effect can be enhanced.

[Example] The present invention will be described in detail 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 the figure, 1 is a cylindrical casing supported by support legs 2 equipped with a vibration isolator, and 3 is a cylindrical peripheral wall. The basket has a section 3a, a bottom wall section 3b, and an annular end wall 3c.

This basket 3 has a boss portion 3d at the center of its bottom portion 3b.
A rotating shaft 4 attached to the boss portion 3d is supported by a bearing device 5 provided at the bottom of the casing 1. The lower end of the rotating shaft 4 is connected to a rotational drive source 6 consisting of a hydraulic motor or the like, and the basket 3 is rotationally driven by the drive source. A large number of permeation holes 3e are formed in the peripheral wall 3a of the basket 3, and an annular groove 3f surrounding the boss 3d is provided in the bottom 3b. The wall portion 311 on the outer peripheral side of the groove portion 3f is inclined upwardly and gradually outward in the radial direction. A filter 7 is disposed across the inner periphery of the peripheral wall 3a, the inner surface of the end wall 3c, and the inner surface of the bottom 3b of the basket.

Reference numeral 8 indicates a liquid supply pipe, and reference numeral 9 indicates a solid matter discharge pipe, which 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 raw liquid or the cleaning liquid toward the peripheral wall of the basket 1 from these ejection holes. Note that this liquid supply pipe may be one in which only the lower end thereof is open.

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

Reference numeral 10 denotes a solid matter scraping device, and this scraping device includes a rotary shaft 10a that is rotatably and slidably provided through the lid plate 1a of the casing l in an airtight structure, and a rotary shaft 10a that is rotatably and slidably provided through the lid plate 1a of the casing l. It is equipped with an attached scraping blade 10b.

Although not shown, on the cover plate 1a of the casing 1, there is provided a scraping device equipped with an elevating mechanism that raises and lowers the rotating shaft 10a of the scraping device, and a rotating mechanism that rotates the rotating shaft 10a. A device drive mechanism is provided.

For example, an electric motor is used as a drive source for this scraping device drive mechanism.

Pulp 12 is supplied to the lid plate 1a of the casing l through a pipe 11.
The pulp 12 is connected to a cleaning liquid supply source (not shown). Further, a valve 14 is connected to a drain port 1b provided at the bottom of the casing 1 via a pipe 13.
By closing the valve 14, liquid can be stored in the casing 1. Peripheral wall part I of casing 1
A plurality of wings 15 are attached to the inner periphery of C at appropriate intervals in the circumferential direction.

When processing the stock solution using the centrifugal separator described above, the rotating shaft 10a of the scraping device 10 is pulled up and the scraping blade 10b is retracted to the rotating shaft side of the basket. Then, the rotation drive source 6 is activated to rotate the basket 3 at high speed, and the stock solution is supplied into the basket 3 from the liquid supply pipe 8. After the supply of the stock solution is finished, the basket is rotated at high speed for a certain period of time to perform a liquid removal process. After the liquid removal process is completed, the cleaning liquid is supplied from the liquid supply pipe 8 while maintaining the rotation of the basket to clean the solid matter (cake) formed on the inner periphery of the basket. Next, the supply of the cleaning liquid is stopped, and the basket 3 is further rotated for a certain period of time to remove liquid. After the liquid removal is completed, the basket is braked to reduce the rotational speed of the basket to the scraping rotational speed. After the rotational speed of the basket has decreased to the scraping speed, the rotating shaft 10a is rotated to allow the scraping blade 10b to enter the solid material layer on the inner circumference of the basket, thereby scraping off the solid material and removing it from the bottom of the basket. Let it fall to the side. The solid matter is scraped off while gradually moving the rotating shaft 10a downward. In this process, a suction device (not shown) is operated to suck the solids in the groove 3f through the solids discharge pipe 9, and discharge the solids to the outside through the solids discharge pipe.

This solid material is transported by pneumatic conveyance and sent to the next step.

After the solid matter has been discharged, the solid matter scraping device 10 is returned to its original position, the stock solution is supplied again, and the above steps are repeated.

After processing a predetermined amount of the stock solution, the filter 7 is cleaned by the method of the present invention. When cleaning the filter 7, after discharging the solid matter, close the valve 14 and remove the pulp 1.
2 is opened and the cleaning liquid is injected into the casing 1 through the pulp 12. Water or hot water is usually used as this cleaning liquid. As shown in FIG.
The basket 3 is rotated at a high speed while it is filled. When the basket is rotated, the cleaning liquid cannot follow the basket at first, so a relative displacement occurs between the basket and the cleaning liquid in the circumferential direction, and the cleaning liquid hits the solid particles attached to the filter 7 from the circumferential direction of the basket. . This causes solid particles to become detached from the filter fibers or grid.

After a certain period of time has passed after rotating the basket, the cleaning liquid 16 will be in a state of rotating at the same speed as the basket,
The cleaning effect will be weakened. In order to enhance the cleaning effect even in this state, it is preferable to place obstacles in the flow of the cleaning liquid to create turbulence. - Generally, a scraping device, a liquid supply pipe, etc. are provided inside the basket, and since these act as obstacles, they can cause a turbulent flow of the cleaning liquid. In order to enhance the cleaning effect of this turbulent flow, it is preferable to orient the scraping blade 10b in a direction at an angle to the inner circumferential surface of the basket 3 to 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 of the turbulent flow is produced evenly over the entire area in the axial direction of the basket. Further, as shown in the figure, if wings 15 are attached to the inner periphery of the casing 1, turbulent flow of the cleaning liquid can be generated, and the cleaning effect can be enhanced.

In order to further enhance the cleaning effect, it is preferable to lengthen the time during which relative displacement occurs between the basket and the cleaning liquid. For this purpose, it is preferable, for example, to alternately rotate the basket in one direction and suddenly decelerate or stop the basket.

Further, even if the basket is rotated in one direction and rotated in the other direction alternately, the cleaning effect can be enhanced for the same reason.

Sudden acceleration/deceleration of the basket, switching of rotation direction, etc. when cleaning the filter may be performed automatically by a sequencer according to a pre-created program, or may be performed by a switch operation by the driver. In any case, the time for cleaning the filter is set to be long enough to remove solid particles from the filter.

After 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, there is a possibility that the solids in the cleaning liquid will adhere to the filter again. In such a case, in order to ensure complete cleaning of the filter, it is preferable to close the valve 14 and repeat the same filter cleaning process as described above.

[Effects of the Invention] As described above, according to the present invention, by injecting the cleaning liquid into the casing and rotating the basket in the cleaning liquid, the flow of the cleaning liquid generated along the circumferential direction of the basket can be applied to the filter. By applying the liquid to the solid particles, the probability of solid particles clogging the filter can be reduced, compared to conventional cleaning methods in which the cleaning liquid was sprayed radially outward of the basket from the liquid supply pipe. Compared to the case using this method, the amount of solid matter remaining in the filter can be reduced, and the cleaning effect can be improved.

In particular, if the basket is repeatedly rotated and suddenly decelerated or suddenly stopped as in the invention described in claim 2, or if the direction of rotation of the basket is reversed as in the invention as claimed in claim 3, it will hit solid particles. Since the flow of the cleaning liquid can be varied in a complicated manner, the cleaning effect can be enhanced.

Further, if obstacles are placed in the flow of the cleaning liquid to create a turbulent flow of the cleaning liquid as in the inventions described in claims 4 to 6, the flow of the cleaning liquid that hits the solid particles will be further complicated and the cleaning effect will be improved. It can be further improved.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing an example of the configuration of a centrifuge 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 being cleaned by the method of the present invention, and Fig. FIG. 2 is a cross-sectional view of a main part showing a state in which a filter is clogged when a conventional cleaning method is used. 1...Casing, 3...Basket, 3e...
Transmission hole, 4... Rotating shaft, 7... Filter, 8...
Liquid supply pipe, 9... Solid matter discharge pipe, 10... Solid matter scraping device, 10b... Scraping blade, 15... Feather.

Claims (6)

[Claims] (1) A casing, a basket disposed within the casing, a filter disposed on the inner circumference of the basket, and a solid matter scraping device for scraping solid matter formed on the inner circumference of the basket. In the method for cleaning the filter of a centrifugal separator in which a liquid is permeated through the filter and a permeation hole provided in a peripheral wall of a basket, a cleaning liquid is injected into the casing, and in the cleaning liquid in the casing. A method for cleaning a filter of a centrifugal separator, characterized in that the filter is cleaned by rotating the basket. (2) A casing, a basket disposed within the casing, a filter disposed on the inner periphery of the basket, and a solid matter scraping device for scraping solid matter formed on the inner periphery of the basket. In the method for cleaning the filter of a centrifugal separator in which a liquid is permeated through the filter and a permeation hole provided in a peripheral wall of a basket, a cleaning liquid is injected into the casing, and in the cleaning liquid in the casing. A method for cleaning a filter for a centrifugal separator, characterized in that the filter is cleaned by alternately rotating the basket and rapidly decelerating or stopping the basket. (3) A casing, a basket disposed within the casing, a filter disposed on the inner periphery of the basket, and a solid matter scraping device for scraping solid matter formed on the inner periphery of the basket. In the method for cleaning the filter of a centrifugal separator in which a liquid is permeated through the filter and a permeation hole provided in a peripheral wall of a basket, a cleaning liquid is injected into the casing, and in the cleaning liquid in the casing. A method for cleaning a centrifuge filter, characterized in that the filter is cleaned by alternately rotating the basket in one direction and the other direction. (4) According to any one of claims 1 to 3, an obstacle is arranged in the flow of the cleaning liquid generated in the casing due to rotation of the basket to generate a turbulent flow of the cleaning liquid in the casing. The centrifuge filter cleaning method described. (5) The filter cleaning method for a centrifugal separator according to claim 4, characterized in that a scraping blade of the solid matter scraping device is used as an obstacle for generating the turbulent flow. (6) The method for cleaning a centrifuge filter according to claim 4 or 5, characterized in that a blade is attached to the inner surface of the casing and the blade is used as the obstacle.