Sludge volume calculation device and centrifugal sludge removal device equipped with the device

Abstract

To provide a sludge amount calculation device that issues a warning and disables the re-operation of a centrifugal sludge removal device when the amount of sludge accumulated in the rotary bowl of the centrifugal sludge removal device exceeds a certain amount. [Solution] The sludge amount calculation device 1 of the present invention, which calculates the amount of sludge accumulated in the rotating bowl 103b of a centrifugal sludge removal device 100, is equipped with a rotation period detection unit 6 that detects the rotation period of the rotating bowl 103b, an arrival time measurement unit 7 that measures the arrival time from when the rotation stop switch 101a of the rotating bowl 103b is pressed until the rotation period of the rotating bowl 103b reaches a predetermined period, and a sludge amount calculation unit 8 that calculates the amount of sludge accumulated in the rotating bowl 103b using the arrival time.

Description

[Technical Field]

[0001] The present invention relates to a sludge amount calculation device that calculates the amount of sludge accumulated in the rotating bowl of a centrifugal sludge removal device that separates and removes settled solids from a machining fluid using centrifugal force, and to a centrifugal sludge removal device equipped with a sludge amount calculation device. [Background technology]

[0002] When processing metals, electronic components, food, etc., machining fluids such as water and oil are used. Machining fluids reduce friction during cutting and grinding, remove chips, and also act as a coolant and rust preventative. Because such machining fluids are circulated, impurities known as settled solids gradually become mixed into the machining fluid, causing the properties of the machining fluid to change. Therefore, centrifugal sludge removal devices are used to remove settled solids from the machining fluid.

[0003] Centrifugal sludge removal devices filter machining fluid by pouring it into a rotating bowl and depositing the solids in the fluid on the inner surface of the rotating bowl using centrifugal force. However, if the sludge accumulated on the inner surface of the rotating bowl exceeds a certain amount, the device will no longer be able to perform its normal filtering function. For this reason, regular cleaning work is required to remove the sludge that has accumulated on the rotating bowl.

[0004] Patent Document 1 discloses an overflow centrifuge that allows for efficient cleaning work. The overflow centrifuge described in Patent Document 1 has a structure that allows the rotating bowl to be freely removed from the rotating shaft, making it possible to easily remove accumulated sludge and improving the efficiency of cleaning work. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Utility Model Application Publication No. 5-9652 Summary of the Invention [Problem to be solved by the invention]

[0006] As mentioned above, sludge gradually accumulates in the rotating bowl, but the amount of sludge accumulation cannot be uniformly controlled because it varies depending on the operating conditions of the machine. As a result, even when cleaning is required, sludge may not be removed, and the resulting increase in settled solids in the machining fluid may have a negative impact on the machining machine and the workpiece.

[0007] The present invention has been made in consideration of the above-mentioned problems, and provides a sludge amount calculation device that can calculate the amount of sludge accumulated in the rotating bowl of a centrifugal sludge removal device, and also provides a sludge amount calculation device that has the function of issuing a warning and prohibiting the centrifugal sludge removal device from restarting when the amount of sludge accumulated exceeds a certain amount. [Means for solving the problem]

[0008] The present invention provides a sludge amount calculation device for calculating the amount of sludge accumulated in a rotary bowl of a centrifugal sludge removal device, comprising: a rotation period detection unit that detects the rotation period of the rotating bowl; a time-to-reach measurement unit that measures the time it takes for the rotation stop switch of the rotating bowl to be pressed until a predetermined rotation period is reached; and a sludge amount calculation unit that calculates the amount of sludge accumulated in the rotating bowl from a relational expression between the rotation period of the rotating bowl, the arrival time, and the amount of sludge accumulated in the rotating bowl. [Effects of the Invention]

[0009] The sludge amount calculation device of the present invention measures the rotation period from when the stop switch of the centrifugal sludge removal device is pressed upon completion of processing work until the rotation of the rotating bowl stops, and calculates the amount of sludge in the rotating bowl from the relational expression between this rotation period, the time it takes to reach a predetermined rotation period, and the amount of sludge accumulated in the rotating bowl. Furthermore, if the rotation period a certain amount of time has elapsed since the stop switch was pressed is longer than the set rotation period, it issues a warning to clean the rotating bowl and prohibits (disables) restarting of the centrifugal sludge removal device, preventing adverse effects on the processing machine and the object to be processed. [Brief explanation of the drawings]

[0010] [Figure 1] 1A is a front view showing a state in which a sludge amount calculation device according to an embodiment of the present invention is attached to a centrifugal sludge removal device, and FIG. 1B is an enlarged view of a rotation period detection unit. [Figure 2] 1 is an exploded view showing a state in which a rotary bowl of a centrifugal sludge removal device according to an embodiment of the present invention is removed. FIG. [Figure 3] 1A is a diagram illustrating the inflow of machining fluid into a sludge amount calculation device and a centrifugal sludge removal device according to an embodiment of the present invention; FIG. 1B is a diagram illustrating the accumulation of settled solids in the machining fluid (accumulated as sludge); FIG. 1C is a diagram illustrating the outflow of machining fluid; and FIG. 1D is a diagram illustrating the accumulation of sludge in the rotating bowl due to the rotation of the rotating bowl. [Figure 4] FIG. 10 is a diagram showing the time until the rotary bowl stops depending on the amount of sludge accumulated according to the embodiment of the present invention. [Figure 5] FIG. 10 is a diagram showing the relationship between the time after the motor is stopped and the rotation period of the rotating bowl according to the embodiment of the present invention. [Figure 6] 1 is a block diagram showing an example of the hardware configuration of a sludge amount calculation device and a centrifugal sludge removal device according to an embodiment of the present invention. [Figure 7] FIG. 1 is a flow chart showing a process from when a stop signal of a centrifugal sludge removal device according to an embodiment of the present invention is pressed to when a cleaning warning is issued to notify the user of cleaning of the rotary bowl. DETAILED DESCRIPTION OF THE INVENTION

[0011] The sludge amount calculation device of the present invention will be described below with reference to the drawings. Note that the drawings are schematic representations of the components of the sludge amount calculation device and peripheral components thereof, and the dimensions and dimensional ratios in the drawings do not necessarily correspond to the actual dimensions and dimensional ratios. Furthermore, unless otherwise specified, for convenience, directions such as up and down are expressed based on the orientation of the sludge amount calculation device shown in Figure 1. Duplicate explanations will be omitted where appropriate, and the same symbols may be used to refer to the same components.

[0012] The sludge amount calculation device 1 (see FIG. 6) according to the embodiment of the present invention may be retrofitted to a centrifugal sludge removal device 100 that is already on the market, or may be manufactured as an integral part of the centrifugal sludge removal device 100 as a part of its functions, and sold as a centrifugal sludge removal device equipped with this device. The centrifugal sludge removal device 100 shown in Fig. 1 is installed next to a processing machine or the like (not shown) and is used to remove settled solids 3 from machining fluid 2 circulating within the processing machine. The machining fluid 2 (see Fig. 3) flows into the centrifugal sludge removal device 100 from an outer cover inlet 103d (see Fig. 3) described below and flows out from an outlet 103f. The settled solids 3 are removed from the machining fluid 2 flowing out of the centrifugal sludge removal device 100 by the centrifugal sludge removal device 100, and the machining fluid 2 is returned to the processing machine and circulated again.

[0013] The process of removing the settled solids 3 from the machining fluid 2 by the centrifugal sludge removal device 100 will be described below. 1A is a front view showing a sludge amount calculation device according to an embodiment of the present invention attached to a centrifugal sludge removal device, and FIG. 1B is an enlarged view of a rotation period detection unit. As shown in FIG. 1, centrifugal sludge removal device 100 includes motor 101, power transmission unit 102 that transmits the power of motor 101, and centrifugal separation unit 103. Power transmission unit 102 has pulley 102a and belt 102b, and transmits the power of motor 101 to centrifugal separation unit 103. Centrifugal separation unit 103 includes rotating shaft 103a that rotates by the power of motor 101, cylindrical rotating bowl 103b that is fitted onto rotating shaft 103a and rotated by rotating shaft 103a, and case 103c that houses rotating bowl 103b.

[0014] The rotating bowl 103b is provided with an inner lid 103g, and an inner lid inlet 103h for the machining fluid 2 is formed in the center of the inner lid 103g. An outer lid 103e that covers the top of the rotating bowl 103b is provided in the case portion 103c. As shown in FIG. 2, the rotating bowl 103b can be taken in and out of the case portion 103c by opening the outer lid 103e. An outer lid inlet 103d is formed in the outer lid 103e, through which the machining fluid 2 flows.

[0015] The outer lid inlet 103d extends in the axial direction of the cylindrical rotating bowl 103b and penetrates the inner lid inlet 103h of the rotating bowl 103b. Therefore, as shown in Figure 3(a), when the machining fluid 2 flows in through the outer lid inlet 103d with the outer lid 103e closed, the machining fluid 2 accumulates inside the rotating bowl 103b. An outlet 103f is formed in the case portion 103c, and the machining fluid 2 from which the settled solids 3 have been removed flows out from the outlet 103f and returns to the processing machine.

[0016] Figure 2 is an exploded view showing the state in which the rotating bowl of the centrifugal sludge removal device according to an embodiment of the present invention has been removed. As shown in Figure 2, to collect the sludge 4, the outer lid 103e of the case 103c is opened, and the machining fluid 2 remaining in the rotating bowl 103b is discharged using a manual pump or the like (not shown). The rotating bowl 103b fitted to the rotating shaft 103a is removed from the case 103c by pulling it upward. The inner lid 103g of the rotating bowl 103b removed from the case 103c is then removed, and the sludge 4 in the rotating bowl 103b is removed.

[0017] FIG. 3 shows (a) the inflow of machining fluid into a sludge amount calculation device and a centrifugal sludge removal device according to an embodiment of the present invention, (b) the accumulation of settled solids in the machining fluid (accumulation as sludge), (c) the outflow of machining fluid, and (d) the accumulation of sludge in the rotating bowl due to the rotation of the rotating bowl. Rotating bowl 103b is rotated by the power of motor 101, and a strong centrifugal force (500 to 1500 times that of gravity) is continuously applied to the machining fluid. Settling solids 3, which have a higher specific gravity than machining fluid 2, are pressed against the inner circumferential surface of rotating bowl 103b and accumulate as sludge 4, and the settling solids 3 are separated from machining fluid 2. As shown in Fig. 3(c), the machining fluid 2 from which the settled solids 3 have been removed overflows from the inner cover inlet 103h and flows out from the outlet 103f. The sludge 4 pressed against the inner circumferential surface of the rotary bowl 103b shown in Fig. 3(d) is dewatered or deoiled and extracted as solids.

[0018] The sludge amount calculation device 1 according to the embodiment of the present invention calculates the weight of sludge 4 accumulated in the rotating bowl 103b by detecting the period of rotation of the rotating bowl 103b after the rotation stop switch 101a of the motor 101 (see FIG. 6) is pressed. Note that pressing the rotation stop switch 101a means stopping the power supply to the drive motor. A method for calculating the weight of the sludge 4 will be described below. Considering the rotational motion of the rotating bowl 103b in the centrifugal sludge removal device 100, the kinetic energy E is expressed by the following equation. E=1 / 2Jω 2 J: Moment of inertia (kg m 2 ) ω: Angular velocity (rad / s) If the weight of the rotating bowl 103b rotating at a position a distance R (m) from the center of rotation of the rotating bowl 103b is G (kg), the moment of inertia of the rotating bowl 103b is J=GR 2 This becomes:

[0019] Thus, the moment of inertia J depends on the weight G of the rotating bowl 103b. When the rotating bowl 103b is rotated at the same angular velocity ω, the greater the weight G of the rotating bowl 103b, the greater the moment of inertia J. The greater the moment of inertia J, the greater the kinetic energy and the longer it takes for the rotating bowl 103b to stop. Here, the weight of the rotating bowl 103b is the sum of the weight of the rotating bowl 103b itself, the weight of the machining fluid 2 accumulated in the rotating bowl 103b, and the weight of the sludge 4 accumulated on the inner circumferential surface of the rotating bowl. Because the weight of the sludge 4 per unit pile is heavier than the machining fluid 2, the weight of the rotating bowl 103b increases as the sludge 4 piles up. Therefore, the weight of the sludge 4 accumulated on the rotating bowl 103b can be calculated by clarifying the relationship between the weight of the rotating bowl 103b and its moment of inertia. Specifically, the weight of the sludge 4 accumulated in the rotating bowl 103b can be calculated by determining the relationship between the time from when the rotation stop switch 101a of the motor 101 is pressed until the rotating bowl 103b stops and the weight of the rotating bowl 103b.

[0020] FIG. 4 is a diagram showing the relationship between the amount of accumulated sludge and the time until the rotating bowl 103b stops according to one embodiment of the present invention. In this example, the rotating bowl 103b was considered to have stopped when the rotation period of the rotating bowl 103b reached one second or more. In FIG. 4, the vertical axis represents the time (rotation stop time in seconds) from when the rotation stop switch 101a was pressed until the rotating bowl 103b stopped, and the horizontal axis represents the weight of the sludge 4 accumulated in the rotating bowl 103b (amount of accumulated sludge in kg). The amount of accumulated sludge was calculated by subtracting the weight of the rotating bowl 103b itself and the weight of the machining fluid from the total weight of the rotating bowl after it stopped (weight of the rotating bowl 103b itself + weight of the sludge 4 + weight of the machining fluid).

[0021] As shown in FIG. 4, as the total weight inside the rotating bowl 103b increases (as the amount of sludge 4 accumulated increases), the time until the rotating bowl 103b stops increases. For example, when 3 kg of sludge 4 accumulates, the time until the rotating bowl 103b stops is approximately 69 seconds. When 2 kg of sludge 4 accumulates, the time until the rotating bowl 103b stops is approximately 66 seconds. This indicates that the weight of the sludge 4 accumulated in the rotating bowl 103b can be calculated from the relationship between the total weight inside the rotating bowl 103b and the time until the bowl 103b stops. Note that in the experiment shown in FIG. 4, the rotating bowl 103b was rotated at the same angular velocity ω regardless of changes in the total weight of the machining fluid 2 and sludge 4 inside the rotating bowl 103b, and the time from when the rotation stop switch 101a of the motor 101 was pressed until the rotating bowl 103b stopped was measured.

[0022] Fig. 5 is a diagram showing the relationship between the time after the motor is stopped and the rotation period of the rotating bowl 103b according to an embodiment of the present invention. In Fig. 4, when 3 kg of sludge 4 has accumulated in the rotating bowl 103b, it takes approximately 69 seconds for the rotating bowl 103b to stop. In this embodiment, the rotation period of the rotating bowl 103b is 0.03 seconds, driven by the motor 101, just before the rotation stop switch 101a is pressed. When the rotation stop switch 101a is pressed, the rotation of the rotating bowl 103b is caused by the moment of inertia, and the rotation period is approximated by the following formula: TIFF0007804969000002.tif659

[0023] If we calculate the coefficient k from these, when the sludge 4 is 3 kg, T(t) = T0 × e 0.0509t Similarly, if the sludge 4 is 2 kg, T(t) = T0 × e 0.0532t If the sludge 4 is 1 kg, T(t) = T0 × e 0.0562t Figure 5 is a graph of these. By storing the rotation period from when rotation stop switch 101a is pressed until rotating bowl 103b stops for each accumulated sludge amount in a database, it is possible to calculate the weight of sludge 4 accumulated in rotating bowl 103b without waiting for rotating bowl 103b to stop.

[0024] 5, if the rotation period is about 0.38 seconds about 50 seconds after the rotation stop switch 101a is pressed, it can be calculated that about 3 kg of sludge 4 has accumulated, if the rotation period is about 0.5 seconds, it can be calculated that about 1 kg of sludge 4 has accumulated, and if the rotation period is 0.7 seconds after 60 seconds, it can be calculated that about 2 kg of sludge 4 has accumulated.

[0025] To reiterate, in this embodiment, the rotating bowl 103b of the centrifugal sludge removal device 100 rotates at the same angular velocity ω (rotation period: 0.001 seconds) during use. After the rotation stop switch 101a of the motor 101 is pressed, the rotating bowl 103b rotates due to its moment of inertia, and the rotation period increases over time until it stops. The amount of sludge 4 accumulated in the rotating bowl 103b can be calculated from the relationship between the rotation period and the amount of sludge accumulated a predetermined time after the rotation stop switch 101a is pressed.

[0026] 6 is a block diagram of a sludge amount calculation device 1 and a centrifugal sludge removal device 100 according to an embodiment of the present invention. The sludge amount calculation device 1 according to the embodiment of the present invention includes a rotation period detection unit 6 that detects the rotation period of the rotating bowl 103b, and an arrival time measurement unit 7 that measures the arrival time from when the rotation stop switch 101a of the motor 101 is pressed until the rotation period of the rotating bowl 103b reaches a predetermined rotation period.

[0027] The rotation period detection unit 6 includes a sensor unit 6a (see FIG. 1) that measures the rotation period of the rotating shaft 103a and a detected portion 6b (see FIG. 1) that is the detection target. In the sludge amount calculation device 1 according to the embodiment of the present invention, a high-frequency proximity sensor is used for the sensor unit 6a. When the metal detected portion 6b attached to the rotating shaft 103a approaches the sensor unit 6a, eddy currents flow on the surface of the detected portion 6b, causing a change in the magnetic field. The rotation period of the rotating shaft 103a is detected by detecting this change in the magnetic field. Note that the rotation period detection unit 6 is not limited to a proximity sensor; a transmission-type photointerrupter using a slit plate and a photosensor may also be used. Rotation can also be detected using a reflector and a reflective photosensor. Various other methods for rotation detection, such as using an encoder, can be used.

[0028] As described above, the rotation period detection unit 6 detects the rotation period of the rotating shaft 103a, but the rotation period of the rotating shaft 103a slows down over time after the rotation stop switch 101a of the motor 101 is pressed, and it takes a certain amount of time for the rotating shaft 103a to stop completely. Therefore, in this embodiment, when the rotation period of the rotating shaft 103a reaches one second, the rotating shaft 103a is considered to have stopped, and a rotating shaft stop signal is output to the arrival time measurement unit 7.

[0029] The arrival time measurement unit 7 measures the arrival time from when the rotation stop switch 101a of the motor 101 is pressed until the rotation period of the rotating bowl 103b reaches a predetermined rotation period, and also measures the time from when the rotation stop switch 101a of the motor 101 is pressed until a rotation stop signal for the rotating shaft 103a is output from the rotation period detection unit 6. The arrival time measurement unit 7 transmits the time until the rotation period reaches the predetermined period and / or the time required for the rotating bowl 103b to stop to the sludge amount calculation unit 8. It is preferable that the arrival time measurement unit 7 is a timer.

[0030] Sludge amount calculation unit 8 stores a plurality of data items related to the total weight of rotating bowl 103b, the rotation period of rotating bowl 103b after rotation stop switch 101a of motor 101 is pressed, and the total weight of rotating bowl 103b and the time from when rotation stop switch 101a is pressed until rotating bowl 103b stops. Sludge amount calculation unit 8 calculates the weight of sludge 4 accumulated in rotating bowl 103b from these data items. Control unit 12 receives the weight (data) of sludge 4 from sludge amount calculation unit 8, references the data stored in sludge amount calculation unit 8, and determines whether or not cleaning of rotating bowl 103b is necessary. If it determines that cleaning is necessary, it issues a warning (flashing warning lamp 9 and sounding warning buzzer 10) requesting cleaning of rotating bowl 103b.

[0031] FIG. 7 is a flowchart of a cleaning warning that notifies the user to clean the rotating bowl 103b when the stop signal of the centrifugal sludge removal device according to an embodiment of the present invention is pressed. When the rotation stop switch 101a of the centrifugal sludge removal device 100 is pressed, the timer, which is the arrival time measurement unit 7, is started, and the rotation period detection unit 6 detects the rotation period of the rotating bowl 103b (S1). The detected rotation period detected by the rotation period detection unit 6 is compared with a predetermined set rotation period. If the detected rotation period is shorter than the set rotation period (less than the predetermined number of seconds), the process returns to S1. If the rotation detection period is longer than the set rotation period (more than the predetermined number of seconds), a timer stop signal is sent to the timer, which stops the timer, and the rotation stop lamp of the centrifugal sludge removal device is illuminated (S4 to S6). The time from when the timer is pressed until it stops is compared with the predetermined time. If the time until it stops is shorter than the set time, cleaning of the rotating bowl 103b is not necessary, and the process ends (S7 to END). If the time from when the timer is pressed until it stops is longer than the preset time, the cleaning lamp lights up, a cleaning warning is output, the cleaning warning buzzer sounds, and operation of the centrifugal sludge removal device is prohibited (S7 to END). When cleaning of the rotating bowl 103b is completed, restarting of the device is permitted by pressing the reset button, and the process ends (S11, S12).

[0032] The cleaning warning buzzer and cleaning warning lamp notify the user of the centrifugal sludge removal apparatus 100 that the amount of accumulated sludge 4 has reached a level that requires cleaning. After the cleaning warning is issued, the centrifugal sludge removal apparatus 100 is prohibited from restarting, and cannot be restarted until the reset switch 11 is pressed after the rotating bowl 103b has been cleaned.

[0033] By installing multiple timers and setting different times for each, it is possible to output sludge accumulation signals in stages. For example, the first timer stores the time when the total weight in the rotating bowl reaches 2 kg as set arrival time A. The second timer stores the time when the amount of sludge reaches a level that requires cleaning, for example 3 kg, as set arrival time B. By using these two timers, the amount of sludge accumulation 4 can be detected in stages.

[0034] The sludge accumulation amount calculation device 1 of the present invention can calculate the amount of sludge accumulated in the rotating bowl from the final stop time from when the stop switch is pressed until the rotating bowl stops rotating, and the equation relating this final stop time to the amount of sludge accumulated in the rotating bowl. Furthermore, if the final stop time exceeds the set stop time, a warning is issued to notify the user that the rotating bowl should be cleaned, and the centrifugal sludge removal device cannot be restarted, thereby preventing adverse effects on the processing machine and the processed object. [Explanation of symbols]

[0035] 1. Sludge volume calculation device 2 Processing fluid 3. Settled solids 4. Sludge 6 Rotation period detection unit 6a Sensor section 6b Detected part 7 Arrival time measurement unit (timer) 8 Sludge volume calculation section 9 Cleaning warning lamp 10 Cleaning warning buzzer 11 Reset switch 12 Control Unit 100 Centrifugal sludge removal device 101 Motor 101a Rotation stop switch 102 Power transmission section 102a Pulley 102b Belt 103 Centrifugal separation section 103a Rotating shaft 103b Rotating Bowl 103c Case part 103d Outer lid inlet 103e Outer lid 103f Outlet 103g inner lid 103h Inner lid inlet

Claims

1. A sludge amount calculation device for calculating the amount of sludge accumulated in a rotary bowl of a centrifugal sludge removal device, a rotation period detection unit that detects the rotation period of the rotating bowl; a time-to-reach measurement unit that measures the time it takes for the rotation stop switch of the rotating bowl to be pressed until a predetermined rotation period is reached; a sludge amount calculation unit that calculates the amount of sludge accumulated in the rotating bowl from a relational expression between the rotation period of the rotating bowl, the arrival time, and the amount of sludge accumulated in the rotating bowl.

2. 2. The sludge amount calculation device according to claim 1, further comprising a control unit that issues a warning to clean the rotating bowl if the stop time from when the rotation stop switch is pressed until the rotating bowl stops is equal to or longer than a predetermined stop time.

3. 2. The sludge amount calculation device according to claim 1, further comprising a control unit that issues a warning to clean the rotating bowl if the rotation period detected by the rotation period detection unit when a predetermined time has elapsed since the rotation stop switch was pressed is longer than a preset rotation period of the rotating bowl.

4. 3. The sludge amount calculation device according to claim 1, wherein the arrival time measurement unit is a timer.

5. A centrifugal sludge removal device comprising the sludge amount calculation device according to claim 1 or 2.

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