Sludge removal device

Abstract

To easily remove sludge contained in dirty coolant liquid discharged from a machine tool at low running costs, discharge the sludge to the outside of the machine tool and improve maintainability of the machine tool and a work environment.SOLUTION: A sludge removal device uses a non-positive displacement liquid feeding pump to pump and feed dirty coolant liquid to a sludge removal box, pumps and feeds the clean coolant liquid from which sludge has been removed from the sludge removal box to a clean coolant tank by using the pressure of the same liquid feeding pump, removes the sludge by a natural sedimentation phenomenon due to gravity within the sludge removal box, flushes the removed sludge to the sludge removal box bottom part with a siphon principle, and easily discharges the sludge accumulated on the sludge removal box bottom part to the outside of the sludge removal box by using the pressure of the liquid feeding pump when necessary.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a device for simply removing sludge contained in a coolant liquid that is circulated in a machine tool and discharging it outside the sludge removal device. [Background technology]

[0002] In cutting, turning, and other processes using machine tools, a relatively small amount of coolant is constantly supplied from a coolant tank to the machine tool during machining operations for the purposes of cooling and lubricating the workpiece and cutting edges, and removing any chips or sludge that is generated from the machining area. Another large amount of so-called bed wash coolant is supplied from the coolant tank to the machine tool for a short period of time at appropriate times, including at the end of machining, for the purpose of flushing out the chips and sludge that have accumulated in the machining chamber of the machine tool. This coolant falls from a drain outlet provided at the bottom of the machining chamber of the machine tool into a coolant tank installed at the bottom of the machine tool, and after the chips and sludge have been removed, it is circulated and reused as filtered coolant. Chips contained in dirty coolant discharged from the bottom of the machining chamber of the machine tool can be easily collected by a chip conveyor installed inside or on top of the coolant tank, but sludge flows into the coolant tank together with the coolant and settles at the bottom of the tank, and the decrease in tank capacity due to the settled sludge leads to a rise in the temperature of the coolant, which leads to a deterioration in the machining accuracy of the machine tool. In addition, the proliferation of viruses attached to the sludge can cause the coolant to spoil, which can cause a foul odor and lead to a deterioration in the working environment, so maintenance work is required to stop the operation of the machine tool and periodically remove the sludge that has settled in the coolant tank and collect it outside the machine tool, which leads to a decrease in the operating rate of the machine tool. Existing sludge removal devices include a solid-liquid separation system using filter paper, a solid-liquid separation system using centrifugal force, and a solid-liquid separation system using magnetic force for magnetic sludge.

[0003] However, in the case of a sludge removal device that uses filter paper, it is necessary to add a backwashing mechanism to prevent the filter paper from clogging and to replace the filter paper regularly. In addition, a separate mechanism is required to discharge the removed sludge outside the sludge removal device. This results in problems such as high equipment costs due to the complexity of the mechanism, high running costs, and machine downtime due to filter paper replacement work.

[0004] In the case of solid-liquid separation using the so-called cyclone method that utilizes centrifugal force, the sludge comes into contact with the inner walls of the cyclone separator at high speed, which wears away the inner walls, necessitating periodic replacement. In addition, a separate mechanism is required to extract only the sludge from the highly concentrated dirty coolant liquid discharged from the bottom of the cyclone separator and transport it outside the machine tool.

[0005] Furthermore, solid-liquid separation means that utilizes magnetic force cannot separate non-magnetic sludge, and therefore a separate mechanism is required to discharge the removed magnetic sludge outside the separation device. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2005-66820 A Summary of the Invention [Problem to be solved by the invention]

[0007] The problem to be solved is to easily remove sludge contained in dirty coolant discharged from a machine tool and discharge it outside the machine tool. [Means for solving the problem]

[0008] The present invention has the following main features: dirty coolant liquid is pumped from the bottom of a collection of water passages formed by a plurality of inclined plate sections arranged at the same inclination angle and the same gap or a plurality of inclined pipe sections having the same inclination angle and the same inner diameter housed in a sealed housing, and the sludge contained in the dirty coolant liquid is removed by sinking it to the bottom of the inclined surface formed by the inclined plate sections or the inner wall surface of the inclined pipe sections on the water passage by a natural settling phenomenon utilizing the specific gravity difference between the coolant liquid and the sludge; and when the non-positive displacement liquid pump is stopped, the coolant liquid in the filtered coolant liquid reservoir flows back inside the water passage due to the siphon principle caused by the difference in height between the liquid level of the dirty coolant tank and the liquid level of the coolant liquid reservoir, causing the sludge that has sunk to the bottom of the inclined surface on the water passage path to be washed away to the bottom of the sludge removal box.

[0009] The sludge removal device of the present invention removes sludge by natural settling, utilizing the difference in specific gravity between the coolant and the sludge, so no filter paper is required. Also, unlike other solid-liquid separation methods, it has the advantage that the sludge can be easily discharged from a sludge removal box placed outside the machine tool using the pressure of the same liquid delivery pump.

[0010] Furthermore, the sludge removal device of the present invention removes sludge contained in the dirty coolant liquid pumped at a low speed by natural settling, so there is almost no wear on the inner wall surface of the sludge removal box, and there is no need for regular replacement or repair work.

[0011] The sludge removal device of the present invention can also remove non-magnetic sludge, which has a higher specific gravity than the coolant liquid, by the natural settling phenomenon.

[0012] The independent dirty coolant tank constituting the present invention is installed for the purpose of temporarily storing the sludge contained in the dirty coolant liquid flowing in directly from the machine tool or via the chip conveyor until it is removed in the sludge removal box, has a liquid level sensor for outputting an operation start signal and an operation stop signal to the liquid feed pump, and has a capacity capable of temporarily storing bed wash coolant liquid between the liquid level at which the operation start signal is output and the upper end height of the dirty coolant tank. Also, between the liquid level at which the operation stop signal is output and the liquid level at which the operation start signal is output, there is a storage capacity capable of accommodating the amount of coolant liquid that flows back from the sludge removal box to the dirty coolant tank because the liquid level of the sludge removal box and the liquid level of the dirty coolant tank become the same due to the siphon principle when the liquid feed pump stops operating.

[0013] The liquid supply pump provided in the dirty coolant tank constituting the present invention pumps the dirty coolant in the dirty coolant tank to the dirty coolant receiving opening at the bottom of the sludge removal box, and the discharge volume is determined by the capacity to pump the total volume of the coolant constantly discharged during machining operations of the machine tool and the bed wash coolant to the sludge removal box by the time of the next bed wash coolant reception. In addition, the liquid supply pump used in the present invention is a non-positive displacement pump, and has the characteristic that the liquid level in the sludge removal box installed downstream and the liquid level in the dirty coolant tank installed upstream become the same when the operation is stopped.

[0014] The independent clean coolant tank constituting the present invention is installed for the purpose of preventing an increase in the temperature of the coolant liquid circulated by the machine tool and for the purpose of acting as a buffer to prevent temporary shortages of coolant liquid caused by fluctuations in the amount of coolant liquid required by the machine tool and differences in the capacity of the liquid supply pump's discharge volume, and is capable of storing the greater of the amount of coolant liquid required to prevent an increase in liquid temperature minus the amount of coolant liquid stored in the dirty coolant tank and sludge removal box and the amount of coolant liquid filled in the piping, or the buffer liquid amount determined by the fluctuations in the amount of coolant liquid required by the machine tool and the discharge volume of the liquid supply pump.

[0015] The dirty coolant liquid is pumped from the dirty coolant tank to the dirty coolant liquid receiving opening at the bottom of the side of the sludge removal box housing by the liquid delivery pump.The flow direction of the dirty coolant liquid is regulated by a baffle plate installed just above the dirty coolant liquid receiving opening on the inside of the housing, and the dirty coolant liquid flows along the bottom of the sludge removal box, pushing the sludge accumulated at the bottom of the sludge removal box toward the sludge discharge opening at the bottom of the opposite side of the sludge removal box.

[0016] With the on-off valve 1 of the sludge discharge opening closed, as the amount of dirty coolant pumped into the sludge removal box increases, the liquid level in the water passage rises, creating an upward flow in the water passage.

[0017] Of the sludge contained in the dirty coolant pumped into the sludge removal box, sludge with a large particle size and a settling velocity greater than the upward flow velocity described above will settle to the bottom of the sludge removal box due to the difference between the upward flow velocity and the settling velocity, and will be swept away by newly pumped dirty coolant toward the sludge discharge opening at the bottom of the opposite side of the sludge removal box.

[0018] Of the sludge contained in the dirty coolant pumped into the sludge removal box, sludge with a small particle size and a settling velocity lower than the upward flow velocity mentioned in the previous section is carried into the water passage of the sludge removal box at the speed difference between the upward flow velocity and the settling velocity.

[0019] The sludge transported to the water passage of the sludge removal box passes through the water passage for a time determined by the discharge volume of the liquid delivery pump and the cross-sectional area and path length of the entire water passage. During this time, the sludge that sinks to the bottom of the inclined surface of the inclined plate or inclined pipe that makes up the water passage is removed from the coolant liquid.

[0020] The filtered coolant that passes through the water passage of the sludge removal box continues to rise and is carried to a filtered coolant reservoir, which is located higher than the liquid level in the dirty coolant tank, and is then pumped from a filtered coolant discharge opening at the top of the filtered coolant reservoir through piping to the clean coolant tank.

[0021] If the angle of repose in the coolant liquid of the sludge that has sunk to the bottom of the inclined surface of the inclined plate section or inclined pipe section that constitutes the water passage of the sludge removal box is less than or equal to the inclination angle of the inclined surface, the sludge will settle down inside the water passage toward the bottom of the sludge removal box and will be swept away by the newly pumped dirty coolant liquid toward the vicinity of the sludge discharge opening at the bottom of the sludge removal box.

[0022] If the angle of repose in the coolant of the sludge that has sunk to the bottom on the inclined surface of the inclined plate or pipe that constitutes the water passage of the sludge removal box is equal to or greater than the inclination angle of the inclined surface, the sludge that has sunk to the bottom will remain on the inclined surface.

[0023] When the liquid level in the dirty coolant tank drops below the set height due to the operation of the liquid feed pump and the operation of the non-positive displacement liquid feed pump stops, the filtered coolant in the filtered coolant pool in the sludge removal box flows backwards through the water passage due to the siphon principle, pushing the sludge that has sunk to the bottom of the inclined surface to the bottom of the sludge removal box, and the sludge that has been pushed to the bottom of the sludge removal box and accumulated there is pushed to the vicinity of the sludge discharge opening at the bottom of the sludge removal box by the dirty coolant newly pumped by the next operation of the liquid feed pump. Note that in order to prevent the amount of filtered coolant stored in the clean coolant tank from decreasing when the liquid feed pump stops operating, the outlet of the piping from the sludge removal box to the clean coolant tank is positioned higher than the liquid level of the clean coolant.

[0024] The sludge that has been swept away to the vicinity of the sludge discharge opening at the bottom of the sludge removal box is discharged outside the sludge removal box by the pressure of the liquid delivery pump, which is achieved by closing valve 2 of the filtered coolant discharge opening and simultaneously opening valve 1 of the sludge discharge opening and operating the liquid delivery pump. [Brief description of the drawings]

[0025] [Figure 1] 1 is a three-view diagram of an apparatus according to the present invention; [Diagram 2] 1 is a cross-sectional view of an apparatus according to the present invention; [Diagram 3] This is an enlarged view of part A of the sludge removal box. [Figure 4] This is an enlarged view of part B of the sludge removal box.

[0026] FIG. 1 is a three-sided view of an embodiment of the device of the present invention. The liquid feed pump pumps the dirty coolant that has flowed into the dirty coolant tank from the machining chamber of the machine tool or the chip conveyor via the dirty coolant receiver to the sludge removal box, and at the same time pumps the filtered coolant from which sludge has been removed in the sludge removal box to the clean coolant tank.

[0027] FIG. 2 is a cross-sectional view of an embodiment of the device of the present invention, in which the inclination angle, length, width and thickness of the inclined plates or inclined pipes or housing, the gap distance between adjacent inclined plates or the inner diameter of the inclined pipes, the number of inclined plates or the number of inclined pipes, and the cross-sectional area of ​​the collection of water passages determined by them, and the time it takes for the dirty coolant to pass through the water passages can be arbitrarily determined depending on the discharge volume of the liquid delivery pump, the required filtration accuracy, and the characteristics of the sludge and coolant, etc. If the discharge volume of the liquid feed pump is the same, the filtration accuracy can be improved by increasing the cross-sectional area of ​​the assembly of water passages, increasing the path length of the water passages, or reducing the gap between adjacent inclined plates or the inner diameter of the inclined pipe. Also, if the specifications of the sludge removal box are the same, the filtration accuracy can be improved by reducing the discharge volume of the liquid feed pump.

[0028] FIG. 3 is an enlarged view of part A of the sludge removal box of the device of the present invention.

[0029] FIG. 4 is an enlarged view of part B of the sludge removal box of the device of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Generally, it is already known from physics that the settling velocity (terminal velocity) of fine particles can be calculated by the following formula 1.

[0031] Stokes' Equation

number

[0032] When the gap between two parallel inclined plates inclined at 60 degrees is 2 mm, the maximum distance at which particles in the water passage formed by the two inclined plates settle vertically due to gravity and land on the adjacent inclined surface is approximately 3.464 mm (3,464 μ). When the discharge volume of the liquid delivery pump is 25 L / min and the total cross-sectional area of ​​the water passage formed by multiple inclined plates is 900 cm, 2 If the length of the water passage is 50 cm, the time required for the upward flow to pass through the water passage is 108 seconds.Assuming that the sludge to be removed is particulate matter that is uniformly distributed within the water passage, and assuming that the specific gravity of the coolant is 1, the kinetic viscosity of the coolant is 1 cst, and the specific gravity of the sludge is 7.8, the same as iron, and that the time from when the sludge starts to settle until it reaches terminal velocity can be ignored, the sludge removal accuracy calculated by comparing the settling distance for each particle size over 108 seconds based on the terminal velocity calculated by Stokes' equation with the maximum landing distance of 3,464 μ is as follows: The terminal velocity of a particle with a particle diameter of 1μ is 3.75μ / sec, so the settling distance in 108 seconds is 405.00μ. Based on this ratio with the maximum landing distance of approximately 3,464μ, 11.7% of the sludge with this particle diameter sinks to the bottom of the inclined surface and is removed from the coolant by settling downward or remaining on the inclined surface. The terminal velocity of a particle with a particle diameter of 2μ is 14.99μ / sec, so the settling distance in 108 seconds is 1,618.92μ. Based on this ratio with the maximum landing distance of approximately 3,464μ, 46.7% of the sludge with this particle diameter sinks to the bottom of the inclined surface and is removed from the coolant by settling downward or remaining on the inclined surface. The terminal velocity of a particle with a particle diameter of 3μ is 33.72μ / sec, so the settling distance in 108 seconds is 3,641.76μ, which is greater than the maximum landing distance of approximately 3,464μ. Therefore, all sludge larger than the particle diameter will sink to the bottom of the inclined surface and be removed from the coolant by settling downward or remaining on the inclined surface.

[0033] The sludge removal box normally removes sludge contained in the dirty coolant with on-off valve 1 closed and on-off valve 2 open, but when the amount of sludge settling at the bottom of the sludge removal box becomes large, the sludge that has settled at the bottom of the sludge removal box can be easily discharged outside the sludge removal box by the pressure of the same on-off valve 1 opening and on-off valve 2 closing and operating the liquid feed pump.

[0034] The sludge removal box can be installed anywhere around the machine tool as long as the position of the filtered coolant reservoir is higher than the liquid level in the dirty coolant tank, which contributes to the recovery of discharged sludge and the efficiency of maintenance work.

[0035] By providing an inspection window on the lower side of the sludge removal box, the amount of accumulated sludge can be visually confirmed and on-off valves 1 and 2 can be operated at the optimal timing to switch from sludge removal operation to sludge discharge operation.

[0036] The capacity of the dirty coolant tank can be determined as a specification that can temporarily store 50 L of bed wash coolant liquid above the liquid level at which the liquid level sensor outputs an operation start signal to the liquid feed pump, assuming that the amount of coolant liquid discharged from the machine tool for a short time and large volume, so-called bed wash, when the machining operation is completed is 50 L with a bed wash pump discharge rate of 200 L / min and operation for 15 seconds. In the above case, if the discharge rate of the liquid feed pump constituting the present invention is 25 L / min, if there is a machining stop time of 2 minutes or more between the end of machining operation and the start of the next machining operation, the liquid level in the dirty coolant tank will be below the liquid feed pump operation start level, and the next bed wash coolant liquid can be received. In addition, even if 50 L of bed wash coolant is discharged from the machine tool during machining operations, if the amount of coolant constantly discharged during machining operations is 20 L / min, if the interval between discharges of bed wash coolant is 10 minutes or more, the liquid level in the dirty coolant tank will be below the level at which the delivery pump begins operating, and the next large volume of coolant will be available.

[0037] The liquid supply pump can be made a submersible pump and submerged in the dirty coolant tank, allowing the height of the dirty coolant tank to be lowered.

[0038] Maintenance can also be improved by carrying the dirty coolant discharged from the machine tool outside the machine tool through piping with a water gradient and installing the dirty coolant tank and liquid supply pump outside the machine tool. [Industrial Applicability]

[0039] The plurality of inclined pipes having the same inclination angle and the same inner diameter forming the water passage may be a composite pipe sharing a partition wall with adjacent pipes, rather than being a collection of independent pipes.

[0040] Even if the specifications of the sludge removal box are the same, the filtration accuracy can be changed by adjusting the discharge volume of the liquid delivery pump, making it easy to select the filtration accuracy according to the machining content performed by the machine tool.The sludge can be easily discharged and collected outside the machine tool, and no consumables are required, which improves the working environment and maintainability and reduces running costs. [Explanation of symbols]

[0041] 1 Clean coolant tank 2 legs 3 Dirty coolant tank 4 Dirty coolant receiver 5Non-positive displacement pump 6 Dirty coolant liquid piping 7 Opening for receiving dirty coolant 8 Sludge removal box 9 On-off valve 1 10 Sludge discharge opening 11 Filtered coolant drain opening 12 On-off valve 2 13 Pipe for filtered coolant 14 rectifier plate 15 Filtered coolant reservoir 16 units 17 waterway 18 Inclined plate or inclined tube 19 slope

Claims

1. The system is composed of a dirty coolant tank, a sludge removal box, and a clean coolant tank. The dirty coolant tank is characterized by being equipped with a non-positive displacement liquid feed pump having a discharge volume equal to or greater than the volume of dirty coolant constantly discharged during machining operations of the machine tool, a liquid level sensor that outputs an operation start signal and an operation stop signal to the liquid feed pump, and piping that connects the discharge port of the liquid feed pump to an opening for receiving dirty coolant at the bottom of the sludge removal box. The sludge removal box has an assembly of water passages formed by a plurality of inclined plate sections arranged at the same inclination angle and the same gap in the center of a sealed housing, or a plurality of inclined pipe sections having the same inclination angle and the same inner diameter, a filtered coolant reservoir at a position higher than the liquid level in the dirty coolant tank at the top of the housing, an opening for discharging filtered coolant at the top of the housing, an opening for receiving dirty coolant at the bottom of the housing, and a sludge removal box at the bottom of the housing. a sludge discharge opening for discharging the filtered coolant liquid at the top of the housing, and piping connecting the filtered coolant discharge opening at the top of the housing to a clean coolant tank. Thus, when the liquid delivery pump is operating, the sludge contained in the dirty coolant liquid carried upward by the upward flow generated in the water passage of the sludge removal box descends vertically on the water passage path due to the difference in specific gravity between the coolant liquid and the sludge, and sinks to the bottom on the inclined surface of the adjacent inclined plate portion or inclined pipe portion and is removed from the coolant liquid. When the liquid delivery pump is stopped, the coolant liquid in the filtered coolant liquid pool flows backwards through the water passage due to the siphon principle caused by the difference in height between the liquid level of the dirty coolant tank and the liquid level of the coolant pool, causing the sludge that has sunk to the bottom on the inclined surface formed by the slope of the inclined plate portion or the inner wall surface of the inclined pipe portion to be washed away to the bottom of the sludge removal box.

2. The sludge removal device of claim 1, characterized in that the dirty coolant liquid receiving opening is located at the bottom of one side of the sludge removal box, the sludge recovery opening is located at the bottom of the opposite side, and the device has a baffle plate for directing the dirty coolant liquid pumped by the liquid delivery pump to the dirty coolant liquid receiving opening along the bottom of the sludge removal box toward the sludge recovery opening, so that sludge that has settled and accumulated at the bottom of the sludge removal box is collected near the sludge recovery opening by the pressure of the same liquid delivery pump.

3. The sludge removal device of claim 1, characterized in that the filtered coolant discharge opening and the sludge discharge opening have on-off valves, the sludge is removed by operating the liquid feed pump with the on-off valve of the filtered coolant discharge opening open and the on-off valve of the sludge discharge opening closed, and the sludge accumulated near the sludge discharge opening of the sludge removal box is discharged outside the sludge removal box by the pressure of the same liquid feed pump by operating the liquid feed pump with the on-off valve of the filtered coolant discharge opening closed and the on-off valve of the sludge discharge opening open.

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