JP2024002442A - Filtering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent initial passage immediately after filter cleaning.

SOLUTION: A filtering device includes: a clean tank 11 in which a clean liquid is stored; a dirty tank 12 in which a used dirty liquid is stored; a filter unit 20 which filters the dirty liquid; a filter pump 13 which sends the dirty liquid to the filter unit 20; cleaning means 30 which cleans a filter 21 of the filter unit 20 with the filter pump 13 stopped; a liquid level detection sensor 40 which detects fluctuation of a liquid level of the clean liquid in the clean tank 11; and pump control means 45 which changes a flow rate of the liquid sent by the filter pump 13 based on the fluctuation of the liquid level detected by the liquid level detection sensor 40. The pump control means 45 reduces the flow rate of the liquid sent by the filter pump 13 to a level lower than that in normal operation when the liquid level detection sensor 40 detects that the liquid level of the clean tank 11 starts rising along with completion of cleaning after the liquid level is lowered by conducting the cleaning.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a filtration device for removing foreign substances present in a liquid such as a coolant liquid used in, for example, a grinding machine, a lathe, a machining center, or the like.

As a coolant filtration device used in machine tools such as grinders and lathes, a device is used that repeatedly filters sludge generated during processing, cleans the filter with accumulated sludge, and restarts filtration. There is.

The present applicant is aware of the following Patent Document 1 as a cutting fluid filtration device having the filter cleaning function as described above.

The above-mentioned Patent Document 1 has the following description.
[Claim 1]
a dirty tank for storing cutting fluid used when machining a workpiece using a machine tool; a filter for filtering impurities contained in the cutting fluid; a pump for supplying the cutting fluid to the filter; A cutting fluid filtration device equipped with a clean tank for storing filtered cutting fluid and a filter cleaning function for cleaning impurities captured by the filter,
two liquid level detectors that detect a lower limit position and an upper limit position of the liquid level of the cutting fluid stored in the clean tank;
Pump control that drives the pump to supply the cutting fluid to the filter when the liquid level of the cutting fluid falls below a lower limit position by the two liquid level detectors, and stops the pump when the upper limit position is detected. Department and
a pump operation time integration unit that integrates the operation time of the pump;
Compare the accumulated time accumulated by the pump operation time accumulation section with a preset cleaning operation interval time of the filter, and if the accumulated time exceeds the cleaning operation interval time, command the cleaning of the filter. a cleaning command unit,
an accumulated time storage unit that stores the accumulated time during which the pump operated from the end of cleaning the filter until the next cleaning;
After cleaning the filter, the operation time of the pump accumulated by the pump operation time accumulation unit is newly accumulated, and the operation time of the pump before the previous filter cleaning is accumulated, and the operation time of the pump is accumulated and the accumulated time storage unit If the newly accumulated accumulated time is longer than the accumulated time before the previous filter cleaning, the cleaning operation interval time is shortened, and if it is shorter, the cleaning operation interval time is changed. a cleaning operation interval time adjustment section that adjusts to lengthen the cleaning operation interval;
A cutting fluid filtration device characterized by having:

Patent No. 5383864

Generally, a filtration device that removes sludge accumulated on a filter by cleaning includes a dirty tank that stores dirty liquid, a filter that filters the dirty liquid in the dirty tank, and a clean tank that stores clean liquid. The clean liquid in the clean tank is supplied to the machine tool, and is returned as dirty liquid from the machine tool to the dirty tank. Dirty liquid in the dirty tank is supplied to a filter by a filter pump, filtered, and turned into clean liquid to be transferred to the clean tank. The sludge accumulated on the filter is removed by the cleaning means, and filtration is restarted with the filter after cleaning.

During filter cleaning, the filter pump is stopped and the supply of dirty liquid to the filter is stopped. Even during filter cleaning, the supply of clean liquid to the machine tool continues, so the level of the clean liquid in the clean tank decreases. When filter cleaning is completed, the filter pump is activated and the supply of dirty liquid to the filter is resumed. The clean liquid that has passed through the filter flows into the clean tank, and the level of the clean liquid in the clean tank is restored.

In such a device, it is necessary to absorb changes in the flow rate of the clean liquid passing through the filter, and the clean liquid is overflowed from the clean tank to the dirty tank when necessary.

That is, during the filtration process in which dirty liquid is passed through a filter and filtered to produce clean liquid, the flow rate of the clean liquid passing through the filter changes over time. In other words, immediately after cleaning, the amount of sludge on the filter surface is small, so the flow rate of the clean liquid passing through the filter is large. On the other hand, as the filtration progresses, the volume of sludge increases, so the flow rate of the clean liquid passing through the filter decreases.

As described above, immediately after cleaning, the flow rate of the liquid passing through the filter is large, so there is a problem in that sludge passes through the filter initially and gets mixed into the clean liquid.

Since it is necessary to ensure the amount of clean liquid supplied to the machine tool, the flow rate of the clean liquid passing through the filter needs to be designed based on the lowest flow rate immediately before cleaning. Therefore, immediately after cleaning, the flow rate is higher than the above-mentioned standard, and an excess amount of clean liquid that is higher than the flow rate of the clean liquid required to be supplied to the machine tool flows into the clean tank. At such times, clean liquid overflows from the clean tank to the dirty tank.

In this way, immediately after cleaning, the clean liquid overflows from the clean tank to the dirty tank, which means that the pump is operated excessively, resulting in a problem of wasted energy.

Further, generally, one filtration device supplies clean liquid to a plurality of machine tools. The number of machine tools in operation may be small, and the amount of clean fluid supplied to the machine tools may be reduced. In this case as well, the flow rate of the clean liquid supplied from the clean tank to the machine tool is lower than the above standard, so the clean liquid overflows from the clean tank to the dirty tank.

In this way, even when the supply of clean liquid decreases, the clean liquid overflows from the clean tank to the dirty tank, which means that the pump is being operated excessively, resulting in wasted energy. There is a problem.

However, the device of Patent Document 1 detects the lower and upper limit positions of the liquid level in the clean tank, and when the liquid level falls below the lower limit position, it drives the pump to supply cutting fluid to the filter, and when the liquid level reaches the upper limit. If so, stop the pump. The pump is simply controlled on and off in response to the upper and lower limits of the liquid level, and cannot prevent the initial passage of sludge immediately after the above-mentioned cleaning.

Furthermore, in a device that detects the upper/lower limits of the liquid level and controls the pump ON/OFF, as in Patent Document 1, ON/OFF control is performed using an electromagnetic contactor (magnet), so frequent ON/OFF operations are required. /OFF shortens the life of the magnetic contactor.

The present invention has been made in view of the above circumstances, and has the following objectives.
To provide a filtration device that prevents initial passage immediately after filter cleaning and suppresses energy waste.

The filtration device according to claim 1 employs the following configuration in order to achieve the above object.
A filtration device for filtering a processing liquid used in a machine tool,
A clean tank in which filtered clean liquid is stored;
a supply pump for supplying the clean liquid from the clean tank to the machine tool;
a dirty tank in which dirty liquid used in the machine tool is stored;
a filter unit having a filter for filtering the dirty liquid into a clean liquid;
a filter pump that sends dirty liquid from the dirty tank to the filter unit;
cleaning means for cleaning the filter of the filter unit with the filter pump stopped;
a liquid level detection sensor that detects fluctuations in the level of the clean liquid in the clean tank;
and a pump control means for varying the liquid feeding flow rate of the filter pump based on the fluctuation in the liquid level detected by the liquid level detection sensor,
The pump control means controls the liquid flow rate of the filter pump at the timing when the liquid level detection sensor detects that the liquid level in the clean tank decreases due to execution of the cleaning and then starts to rise upon completion of cleaning. Initial passage control is performed to reduce the amount of water compared to normal operation for a predetermined period of time.

The filtration device according to claim 2 employs the following configuration in addition to the configuration described in claim 1.
The initial passage control by the above pump control means is as follows:
This is done so that there is no fluctuation in the liquid level in the clean tank detected by the liquid level detection sensor.

The filtration device according to claim 3 employs the following configuration in addition to the configuration described in claim 1.
The initial passage control by the above pump control means is as follows:
This is done so that the fluctuation in the liquid level in the clean tank detected by the liquid level detection sensor increases slightly.

The filtration device according to claim 4 employs the following configuration in addition to the configuration described in claim 1.
The pump control means is
When the flow rate of clean liquid supplied to the machine tool by the supply pump decreases and the level of the clean liquid in the clean tank detected by the liquid level detection sensor slows down, the filter pump increases accordingly. The flow rate of the liquid is controlled to be lower than in normal operation.

The filtration device according to the first aspect is a filtration device for filtering a processing liquid used in a machine tool. The filtration device includes a clean tank, a supply pump, a dirty tank, a filter unit, a filter pump, a cleaning device, a liquid level detection sensor, and a pump control device. The clean tank stores filtered clean liquid. The supply pump is for supplying the clean liquid in the clean tank to the machine tool. The dirty tank stores dirty liquid used by the machine tool. The filter unit has a filter for filtering the dirty liquid into a clean liquid. The filter pump sends the dirty liquid in the dirty tank to the filter unit. The cleaning means cleans the filter of the filter unit while the filter pump is stopped. The liquid level detection sensor detects fluctuations in the liquid level of the clean liquid in the clean tank. The pump control means varies the flow rate of liquid sent by the filter pump based on the variation in the liquid level detected by the liquid level detection sensor. The pump control means causes the filter pump to send liquid at a timing when the liquid level detection sensor detects that the liquid level in the clean tank decreases due to execution of the cleaning and then starts to rise upon completion of cleaning. Initial pass control is performed to reduce the flow rate for a predetermined period of time compared to normal operation.
Therefore, by reducing the flow rate of the liquid sent by the filter pump compared to normal operation after cleaning, when the liquid easily passes through the filter, it is possible to suppress the initial passage of sludge and prevent sludge from mixing with the clean liquid. In addition, by reducing the flow rate of the liquid that passes through the filter after cleaning is completed, the overflow of clean liquid from the clean tank to the dirty tank due to excess clean liquid flowing into the clean tank is reduced, and energy consumption due to excessive pump operation is reduced. There will be no waste.

In the filtration apparatus according to a second aspect of the present invention, the initial passage control by the pump control means is performed so that there is no fluctuation in the liquid level in the clean tank detected by the liquid level detection sensor.
This suppresses the initial passage of sludge and prevents sludge from being mixed into the clean liquid. In addition, by reducing the flow rate of the liquid that passes through the filter after cleaning is completed, the overflow of clean liquid from the clean tank to the dirty tank due to excess clean liquid flowing into the clean tank is reduced, and energy consumption due to excessive pump operation is reduced. There will be no waste.

In the filtration apparatus according to a third aspect of the present invention, the initial passage control by the pump control means is performed so that the fluctuation in the liquid level in the clean tank detected by the liquid level detection sensor increases slightly.
This suppresses the initial passage of sludge and prevents sludge from being mixed into the clean liquid. In addition, by reducing the flow rate of the liquid that passes through the filter after cleaning is completed, the overflow of clean liquid from the clean tank to the dirty tank due to excess clean liquid flowing into the clean tank is reduced, and energy consumption due to excessive pump operation is reduced. There will be no waste.

In the filtration apparatus according to claim 4, the pump control means decreases the flow rate of the clean liquid supplied to the machine tool by the supply pump, and increases the level of the clean liquid in the clean tank detected by the liquid level detection sensor. When the decrease becomes gradual, the flow rate of the liquid sent by the filter pump is controlled to be lower than in normal operation.
When the amount of clean fluid supplied to the machine tool decreases, overflow is reduced by reducing the fluid flow rate of the filter pump, eliminating wasted energy due to excessive pump operation.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the whole structure of the filtration apparatus of one Embodiment of this invention. It is a figure explaining the process by which a cleaning means operates. It is a figure explaining a liquid level detection sensor.

Next, a mode for carrying out the present invention will be described.

[Overall structure]
FIG. 1 shows the overall structure of an embodiment of the filtration device of the present invention.
This embodiment is a filtration device for filtering a machining liquid used in a machine tool (not shown). The illustrated apparatus includes a liquid tank 10 for storing the processing liquid, and a filter unit 20 for filtering the processing liquid.

[Liquid tank 10]
The liquid tank 10 includes a clean tank 11 and a dirty tank 12. The clean tank 11 stores clean liquid that has been filtered by the filter unit 20. The dirty tank 12 stores dirty liquid that has been used by the machine tool and has not yet been filtered. In the illustrated example, the liquid tank 10 is partitioned into two areas by a partition wall 14, one area being the clean tank 11 and the other area being the dirty tank 12. The height of the partition wall 14 is set lower than the depth of the liquid tank 10. This allows the clean liquid to overflow from the clean tank 11 toward the dirty tank 12.

A supply pump 15 is connected to the clean tank 11 for supplying the clean liquid in the clean tank 11 to the machine tool. In addition to the above-mentioned supply pump 15, the supply path 15A for supplying the clean liquid to the machine tool is provided with a supply pressure sensor 16 for detecting supply pressure. The dirty liquid used in the machine tool returns to the dirty tank 12 through the dirty liquid path 18 and is stored therein.

The dirty tank 12 is equipped with a float type liquid level gauge 17. The float type liquid level gauge 17 includes a float 17A for detecting the liquid level and a plurality of proximity sensors 17B for detecting the position of the float 17A.

[Filter unit 20]
The filter unit 20 includes a housing 29, a filter 21, and a filtration chamber 22. The housing 29 houses the filter 21 and the filtration chamber 22. The filter 21 is for filtering the dirty liquid into a clean liquid. The filtration chamber 22 sandwiches the filter 21 therein to form a filtration space therein, as will be described later. A drain pipe 19 is provided at the bottom of the housing 29.

The filter 21 is endlessly wound around four feed rolls 23. One of the four feed rolls 23 is driven by a drive motor 23A. Thereby, the filter 21 is conveyed like a conveyor belt by the operation of the drive motor 23A. By sending the filter 21 as described above, the area of the filter 21 used for filtration can be moved out of the filtration chamber 22, and the area that has been cleaned can be moved into the filtration chamber 22.

The filtration chamber 22 includes an upper shell 22A and a lower shell 22B. The upper shell 22A can move up and down relative to the lower shell 22B to open and close the filtration chamber 22. The vertical movement of the upper shell 22A is driven by a hydraulic motor 24A and a hydraulic cylinder 24B. The vertical position of the upper shell 22A is detected and controlled by upper and lower limit switches 25A and 25B.

The filtration chamber 22 sandwiches the filter 21 between the opening of the upper shell 22A and the opening of the lower shell 22B, and a filtration space is formed inside. When the filtration chamber 22 is closed, the opening of the upper shell 22A and the opening of the lower shell 22B meet, and the filter 21 is sandwiched between them. The liquid is passed through the filtration chamber 22 from top to bottom and filtered by the filter 21 . With the filtration chamber 22 closed, liquid is supplied to the space inside the upper shell 22A, filtered through the filter 21, and the filtered liquid is discharged from the space inside the lower shell 22B. That is, the dirty liquid is introduced into the upper shell 22A, filtered by the filter 21, and the clean liquid is discharged from the lower shell 22B.

A rectifying member (not shown) is disposed inside the upper shell 22A, so that the liquid is distributed over the entire filtration surface of the filter 21 sandwiched between the upper shell 22A and the lower shell 22B for filtration.

A filter pump 13 is arranged in the dirty tank 12 to send the dirty liquid in the dirty tank 12 to the filter unit 20. The dirty liquid stored in the dirty tank 12 is sent to the filtration chamber 22 of the filter unit 20 through the filter path 13A by the filter pump 13. A pressure sensor 13B is arranged in the filter passage 13A to detect the internal pressure of the upper shell 22A.

The filter path 13A is connected to the upper shell 22A, and the dirty liquid is introduced into the upper shell 22A and filtered by the filter 21. The clean liquid obtained by filtration is discharged from the lower shell 22B through the clean liquid path 26 to the clean tank 11 and stored therein.

[Cleaning means 30]
The filtration device of this embodiment includes a cleaning means 30 that cleans the filter 21 of the filter unit 20 while the filter pump 13 is stopped.

The cleaning means 30 includes an air blow nozzle 31, a cleaning nozzle 32, a blowdown path 33, and the like. The air blow nozzle 31 injects compressed air supplied by the compressed air path 31A toward the filter 21. The cleaning nozzle 32 injects cleaning liquid branched from the supply path 15A toward the filter 21. The blowdown passage 33 is used to supply compressed air from the compressed air passage 31A to the filter passage 13A and to discharge the liquid in the filtration chamber 22.

A sludge discharge port 27 for discharging sludge removed from the filter 21 by air blow is formed in the housing 29 so as to be located below the air blow nozzle 31 . A conveyance path 28 for conveying the sludge discharged from the sludge discharge port 27 is arranged below the sludge discharge port 27 .

FIG. 2 is a diagram illustrating a process in which the cleaning means 30 operates.

FIG. 2(A) shows the filtration process.
In the filtration step, the filter 21 is sandwiched between the opening of the upper shell 22A and the opening of the lower shell 22B, and the filtration chamber 22 is closed. In this state, the filter pump 13 is operated to supply dirty liquid from the filter path 13A to the space inside the upper shell 22A. The dirty liquid supplied into the upper shell 22A is distributed over the entire filtration surface of the filter 21 sandwiched between the upper shell 22A and the lower shell 22B by a rectifying member (not shown). By passing through the filtration surface of the filter 21, the sludge of the dirty liquid is captured and filtered by the filter 21, and is sent into the lower shell 22B as a clean liquid. The clean liquid filled in the lower shell 22B is discharged into the clean tank 11 through the clean liquid path 26 and stored therein.

As such filtration continues and sludge accumulates on the filtration surface of the filter 21, the pressure loss of the filter 21 increases and the internal pressure of the upper shell 22A increases. When the pressure sensor 13B detects that the internal pressure of the upper shell 22A has reached a predetermined threshold value, the filtration process is temporarily interrupted and the process proceeds to the blowdown process.

FIG. 2(B) shows the blowdown process.
In the blowdown step, compressed air is introduced into the upper shell 22A through the filter path 13A by stopping the filter pump 13, closing the valve of the filter path 13A, and opening the valve of the blowdown path 33. By introducing this compressed air, the dirty liquid in the upper shell 22A passes through the filter 21 and moves into the lower shell 22B. Also at this time, the clean liquid in the lower shell 22B is discharged into the clean tank 11 through the clean liquid path 26 and stored therein. This blowdown process empties the liquid in the upper shell 22A, making it possible to perform the next cleaning process.

FIG. 2(C) shows the cleaning process.
The cleaning step is performed with the filter pump 13 stopped. The upper shell 22A is raised by the operation of the hydraulic cylinder 24B, and the filter 21 is opened so that it can be moved. Next, the drive motor 23A is operated to feed the filter 21 and move the filtration surface on which sludge has accumulated to the outside of the filtration chamber 22.

While moving the filter 21, the valve of the compressed air passage 31A is opened and compressed air is injected from the air blow nozzle 31 to remove the sludge accumulated on the filter 21. The sludge removed here is discharged from the sludge discharge port 27 and conveyed by the conveyance path 28. Furthermore, the valve of the cleaning path 32A is opened and clean liquid is injected from the cleaning nozzle 32 to wash away the sludge remaining on the filter 21. The sludge-containing liquid washed away here is discharged from the drain pipe 19 to the dirty tank 12.

The cleaned filter 21 is returned to its original position, the upper shell 22A is lowered, the filtration chamber 22 is closed again, and the above-described filtration process is restarted.
Note that the operation of the cleaning means 30 described above is controlled by a pump control means 45, which will be described later.

In the operation of the cleaning means 30 described above, the blowdown process and the cleaning process are performed with the filter pump 13 stopped. Therefore, during the blowdown process and the cleaning process, while the clean liquid in the clean tank 11 is supplied to the machine tool, new clean liquid is not replenished, resulting in a drop in the liquid level.

[Liquid level detection sensor 40]
The filtration device of this embodiment includes a liquid level detection sensor 40 that detects fluctuations in the level of the clean liquid in the clean tank 11.

FIG. 3 is a diagram illustrating the liquid level detection sensor 40.

The liquid level detection sensor 40 includes a float 41, a reflection plate 42, and a reflection type optical sensor 43. The float 41 is a float located on the surface of the clean liquid in the clean tank 11. The reflecting plate 42 is attached to the upper end of a bar extending above the float 41. The reflective optical sensor 43 is arranged so as to face the reflective plate 42, and receives the reflected light from the irradiated light (laser etc.) reflected by the reflective plate 42, and connects the reflective optical sensor 43 with the reflective plate. Measure the distance to 42.

Therefore, when the level of the clean liquid changes, the height position of the float 41 changes, the height position of the reflecting plate 42 changes accordingly, and the distance between the reflective optical sensor 43 and the reflecting plate 42 changes. The distance between the reflective optical sensor 43 and the reflecting plate 42 is measured to detect fluctuations in the liquid level. That is, as the level of the clean liquid increases, the distance between the reflective optical sensor 43 and the reflective plate 42 becomes shorter, and as the level of the clean liquid decreases, the distance between the reflective optical sensor 43 and the reflective plate 42 increases.

[Pump control means 45]
The filtration device of this embodiment includes a pump control means 45 that changes the flow rate of the liquid sent by the filter pump 13 based on the fluctuation in the liquid level detected by the liquid level detection sensor 40.

The pump control means 45 performs initial passage control. In the initial passage control, immediately after the above-described cleaning of the filter 21 is completed, sludge tends to pass through without being captured until a certain amount of sludge has accumulated. By controlling such initial passage, it is possible to suppress sludge from being mixed into the clean liquid immediately after cleaning is completed.

The initial passage control is performed at a timing when the liquid level detection sensor 40 detects that the liquid level in the clean tank 11 decreases due to the execution of the cleaning and then starts to rise upon completion of the cleaning. Decreasing the liquid flow rate from normal operation for a predetermined period of time.

As described above, the blowdown step and cleaning step are performed with the filter pump 13 stopped. Then, when the filtration process is restarted, the filter pump 13 is operated to filter the dirty liquid in the dirty tank, and the clean liquid is refilled into the clean tank 11 as a clean liquid.
Therefore, in the blowdown process and the cleaning process, the level of the clean liquid in the clean tank 11 decreases, and when the filtration process is restarted, the level starts to rise. This change in the liquid level is detected by the liquid level detection sensor 40 described above, and the end of the cleaning is detected.

In the initial passage control, the flow rate of the liquid sent by the filter pump 13 is reduced compared to normal operation for a predetermined period of time at the timing when the liquid level detection sensor 40 detects the end of the cleaning. In this way, by reducing the flow rate of the liquid sent by the filter pump 13 compared to normal operation, it is possible to prevent sludge from passing through without being captured immediately after cleaning, when less sludge is deposited. By controlling the initial passage in this way, mixing of sludge into the clean liquid is suppressed.

The initial passage control by the pump control means 45 can be performed so that the liquid level in the clean tank 11 detected by the liquid level detection sensor 40 does not fluctuate. By restricting the flow rate of the liquid sent by the filter pump 13 so that the liquid level in the clean tank 11 does not fluctuate, it is possible to prevent sludge from passing through without being captured even immediately after cleaning when less sludge is deposited.

This suppresses the initial passage of sludge and prevents sludge from being mixed into the clean liquid. Furthermore, since the flow rate of the liquid passing through the filter is reduced after cleaning is completed, overflow of clean liquid from the clean tank 11 to the dirty tank 12 due to excessive clean liquid flowing into the clean tank 11 is reduced, and excessive pumping Eliminates energy waste due to operation.

The initial passage control by the pump control means 45 can be performed so that the fluctuation in the liquid level in the clean tank 11 detected by the liquid level detection sensor 40 increases slightly. By restricting the flow rate of the liquid sent by the filter pump 13 so that the fluctuation in the liquid level in the clean tank 11 increases slightly, it is possible to prevent sludge from passing through without being captured even immediately after cleaning when there is little sludge accumulation.

This suppresses the initial passage of sludge and prevents sludge from being mixed into the clean liquid. Furthermore, since the flow rate of the liquid passing through the filter is reduced after cleaning is completed, overflow of clean liquid from the clean tank 11 to the dirty tank 12 due to excessive clean liquid flowing into the clean tank 11 is reduced, and excessive pumping Eliminates energy waste due to operation.

The pump control means 45 causes the flow rate of the clean liquid supplied to the machine tool by the supply pump 15 to decrease, and the liquid level of the clean liquid in the clean tank 11 detected by the liquid level detection sensor 40 to gradually decrease. In this case, the flow rate of the liquid sent by the filter pump 13 can be controlled to be lower than that in normal operation.

When the amount of clean liquid supplied to the machine tool decreases, the flow rate of the liquid sent by the filter pump 13 is reduced, thereby reducing overflow and eliminating wasted energy due to excessive pump operation.

[Effects of embodiment]
The filtration device of this embodiment is a filtration device for filtering a machining liquid used in a machine tool. The filtration device includes a clean tank 11, a supply pump 15, a dirty tank 12, a filter unit 20, a filter pump 13, a cleaning means 30, a liquid level detection sensor 40, and a pump control means 45. The clean tank 11 stores filtered clean liquid. The supply pump 15 is for supplying the clean liquid in the clean tank 11 to the machine tool. The dirty tank 12 stores dirty liquid used in the machine tool. The filter unit 20 has a filter 21 for filtering the dirty liquid into a clean liquid. The filter pump 13 sends the dirty liquid in the dirty tank 12 to the filter unit 20 . The cleaning means 30 cleans the filter 21 of the filter unit 20 while the filter pump 13 is stopped. The liquid level detection sensor 40 detects fluctuations in the level of the clean liquid in the clean tank 11 . The pump control means 45 changes the flow rate of the liquid sent by the filter pump 13 based on the fluctuation in the liquid level detected by the liquid level detection sensor 40. Then, the pump control means 45 controls the filter pump at the timing when the liquid level detection sensor 40 detects that the liquid level in the clean tank 11 decreases due to execution of the cleaning and then starts to rise upon completion of cleaning. Initial passage control is performed to reduce the liquid feeding flow rate of No. 13 for a predetermined period of time compared to normal operation.
For this reason, after cleaning, when the liquid easily passes through the filter 21, the flow rate of the liquid sent by the filter pump 13 is reduced compared to normal operation, thereby suppressing the initial passage of sludge and preventing sludge from getting mixed into the clean liquid. can. In addition, since the flow rate of the liquid passing through the filter 21 is reduced after cleaning is completed, the overflow of the clean liquid from the clean tank 11 to the dirty tank 12 due to excessive clean liquid flowing into the clean tank 11 is reduced. Eliminates energy waste due to pump operation.

In the filtration apparatus of this embodiment, the initial passage control by the pump control means 45 is performed so that there is no fluctuation in the liquid level in the clean tank 11 detected by the liquid level detection sensor 40.
This suppresses the initial passage of sludge and prevents sludge from being mixed into the clean liquid. In addition, since the flow rate of the liquid passing through the filter is reduced after cleaning is completed, the overflow of clean liquid from the clean tank to the dirty tank due to excess clean liquid flowing into the clean tank 11 is reduced, and the overflow of clean liquid from the clean tank to the dirty tank due to excessive pump operation is reduced. No more wasted energy.

In the filtration device of this embodiment, the initial passage control by the pump control means is performed so that the fluctuation in the liquid level in the clean tank detected by the liquid level detection sensor increases slightly.
This suppresses the initial passage of sludge and prevents sludge from being mixed into the clean liquid. Furthermore, since the flow rate of the liquid passing through the filter is reduced after cleaning is completed, overflow of clean liquid from the clean tank 11 to the dirty tank 12 due to excessive clean liquid flowing into the clean tank 11 is reduced, and excessive pumping Eliminates energy waste due to operation.

In the filtration device of this embodiment, the pump control means 45 controls the amount of clean liquid in the clean tank 11 detected by the liquid level detection sensor 40 when the supply flow rate of the clean liquid to the machine tool by the supply pump 15 decreases. When the decrease in the liquid level becomes gradual, the flow rate of the liquid sent by the filter pump 13 is controlled to be lower than in normal operation.
When the amount of clean liquid supplied to the machine tool decreases, the flow rate of the liquid sent by the filter pump 13 is reduced, thereby reducing overflow and eliminating wasted energy due to excessive pump operation.

In this embodiment, since ON/OFF control like the above-mentioned patent document 1 is not performed, the problem of the life span of the magnetic contactor is solved. In addition, by using a non-contact inverter, it is possible to lengthen the frequency rise and fall times, and it is possible to suppress the opening and closing noise of the check valve attached to the pump discharge part and water hammer.

[Modified example]
Although particularly preferred embodiments of the present invention have been described above, the present invention is not intended to be limited to the illustrated embodiments, but can be modified and implemented in various ways, and the present invention includes various modified examples. The purpose is to

10: Liquid tank 11: Clean tank 12: Dirty tank 13: Filter pump 13A: Filter path 13B: Pressure sensor 14: Partition wall 15: Supply pump 15A: Supply path 16: Supply pressure sensor 17: Float type liquid level gauge 17A: Float 17B: Proximity sensor 18: Dirty liquid path 19: Drain pipe 20: Filter unit 21: Filter 22: Filtration chamber 22A: Upper shell 22B: Lower shell 23: Feed roll 23A: Drive motor 24A: Hydraulic motor 24B: Hydraulic cylinder 25A : Upper limit switch 25B: Lower limit switch 26: Clean liquid path 27: Sludge discharge port 28: Conveyance path 29: Housing 30: Cleaning means 31: Air blow nozzle 31A: Compressed air path 32: Cleaning nozzle 32A: Cleaning path 33: Blowdown path 40: Liquid level detection sensor 41: Float 42: Reflector plate 43: Reflective optical sensor 45: Pump control means

Claims (4)

A filtration device for filtering a processing liquid used in a machine tool,
A clean tank in which filtered clean liquid is stored;
a supply pump for supplying the clean liquid from the clean tank to the machine tool;
a dirty tank in which dirty liquid used in the machine tool is stored;
a filter unit having a filter for filtering the dirty liquid into a clean liquid;
a filter pump that sends dirty liquid from the dirty tank to the filter unit;
cleaning means for cleaning the filter of the filter unit with the filter pump stopped;
a liquid level detection sensor that detects fluctuations in the level of the clean liquid in the clean tank;
and a pump control means for varying the liquid feeding flow rate of the filter pump based on the fluctuation in the liquid level detected by the liquid level detection sensor,
The pump control means controls the liquid flow rate of the filter pump at the timing when the liquid level detection sensor detects that the liquid level in the clean tank decreases due to execution of the cleaning and then starts to rise upon completion of cleaning. A filtration device characterized by performing initial passage control to reduce the amount of water than normal operation for a predetermined period of time. The initial passage control by the above pump control means is as follows:
The filtration device according to claim 1, wherein the filtering is performed so that there is no fluctuation in the liquid level of the clean tank detected by the liquid level detection sensor. The initial passage control by the above pump control means is as follows:
2. The filtration device according to claim 1, wherein the filtration is performed so that fluctuations in the liquid level of the clean tank detected by the liquid level detection sensor slightly increase. The pump control means is
When the flow rate of clean liquid supplied to the machine tool by the supply pump decreases and the level of the clean liquid in the clean tank detected by the liquid level detection sensor slows down, the filter pump increases accordingly. The filtration device according to claim 1, wherein the liquid feeding flow rate is controlled to be lower than in normal operation.

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