KR20240052026A - liquid spray device - Google Patents

Abstract

The cleaning device (liquid injection device) 10 includes a nozzle 11A that sprays a cleaning liquid (liquid), a pump 12 connected to the nozzle 11A that pressurizes the cleaning liquid and supplies it to the nozzle 11A, A valve 17 that is installed between the nozzle 11A and the pump 12 and controls the distribution of the cleaning liquid by opening and closing, and a valve control unit 21 that controls the opening and closing of the valve 17, and at least closes the valve 17. A valve control unit 21 that outputs a frequency switching signal (signal) and a pump control unit 20 that controls the operation of the pump 12, so as to relieve the degree of pressurization of the cleaning liquid based on the frequency switching signal. It is equipped with a pump control unit 20 that controls the operation of (12).

Description

liquid spray device

The technology disclosed in this specification relates to a liquid injection device.

Conventionally, the system described in Patent Document 1 below has been known as a system for compensating for pressure increases that may occur within various closed spaces of a pump device. The pump system described in Patent Document 1 makes it possible to compensate for the increase in pressure within the chamber of the pump device by operating the pump means of the pump device to compensate for the increase in pressure within the chamber by adjusting the capacity of the chamber. More specifically, in one embodiment, in order to compensate for unnecessary pressure rises on the fluid within the dispensing chamber, the dispensing motor is reversed to return the piston, making it possible to compensate for any pressure rises within the dispensing chamber; there is.

Japanese Patent Application Publication No. 2012-154337

The pump system described in Patent Document 1 above addresses problems that arise when used to coat photoresist chemicals on semiconductor wafers (acceleration of gasification or bubble formation of chemicals due to negative pressure spikes or acceleration of bubble formation due to positive pressure spikes). This was done to solve the problem of cross-linking of polymers. On the other hand, in a liquid injection device that performs cleaning, etc. by spraying liquid pressurized by a pump from a nozzle, when the supply of liquid to the nozzle is controlled by opening and closing a valve, the liquid is released according to the closing of the valve. There was a problem that the pressure rose rapidly and the load on the liquid supply path etc. became excessive. It was difficult to solve such problems with the technology described in Patent Document 1 mentioned above.

The technology described in the specification of this application was completed based on the above-mentioned circumstances, and its purpose is to suppress the increase in pressure of the liquid.

(1) A liquid injection device related to the technology described in the present specification includes a nozzle that sprays liquid, a pump that is connected to the nozzle and pressurizes the liquid and supplies it to the nozzle, and is installed between the nozzle and the pump. A valve that controls the distribution of the liquid by opening and closing, a valve control section that controls opening and closing of the valve, at least a valve control section that outputs a signal when the valve is closed, and a pump control section that controls driving of the pump, It is equipped with a pump control unit that controls the operation of the pump to relieve the degree of pressurization of the liquid based on the signal.

(2) In addition to (1) above, the liquid injection device is equipped with an electric motor for driving the pump and an inverter for rotationally driving the electric motor, and the pump operates according to the rotation state of the electric motor. It may have at least a plunger for pressurizing the liquid, and the pump control unit may control the rotational state of the electric motor by adjusting the driving frequency of the inverter.

(3) In the liquid injection device, in addition to (2) above, even if the valve control unit closes the valve later than the timing at which the driving frequency of the inverter starts to be adjusted by the pump control unit based on the signal, do.

(4) In the liquid injection device, in addition to (3) above, even if the valve control unit closes the valve before the timing at which adjustment of the driving frequency of the inverter is completed by the pump control unit based on the signal, do.

(5) In the liquid injection device, in addition to (4) above, the valve control unit has a timing for closing the valve from the timing at which the driving frequency of the inverter starts to be adjusted by the pump control unit based on the signal. The valve may be closed so that the time until the timing of closing the valve is longer than the time from the timing of closing the valve to the timing of completion of adjustment of the driving frequency of the inverter by the pump control unit.

(6) In addition to any one of (3) to (5) above, the liquid injection device is provided with a plurality of nozzles and a plurality of valves, and the valve control unit includes a timing for closing the valve, and The time difference between the timing at which the driving frequency of the inverter begins to be adjusted by the pump control unit may be increased as the number of nozzles from which injection of the liquid is stopped due to closing of the valve increases.

(7) In the liquid injection device, in addition to any one of (3) to (6) above, the valve control unit adjusts the driving frequency of the inverter based on the signal to reduce the pressure of the liquid. The valve may be closed at a timing before this becomes 0.

(8) In the liquid injection device, in addition to any one of (3) to (7) above, the valve control unit, after the drive frequency begins to be adjusted by the pump control unit, sets the drive frequency, When the number of revolutions per unit time or the elapsed time of the electric motor reaches a threshold, the valve is closed, and the threshold is calculated based on an operating condition related to at least one operation of the valve, the electric motor, and the inverter. It is equipped with an arithmetic unit that

(9) In the liquid injection device, in addition to (8) above, the valve control unit, after the drive frequency begins to be adjusted by the pump control unit, when the drive frequency or the rotation speed reaches the threshold value, the valve control unit Abolish the valve.

(10) In addition to (8) or (9), the liquid injection device is provided with a plurality of nozzles and a plurality of valves, and the calculation unit is based on the number of valves closed by the valve control unit. The threshold value is calculated, and as the number of valves closed by the valve control unit increases, the threshold value related to the driving frequency or the number of rotations is decreased, and the threshold value related to the elapsed time is increased.

(11) In addition to any one of the above (8) to (10), the liquid ejecting device may include: the calculation unit, after the adjustment of the drive frequency by the pump control unit is completed; The first flow rate, which is the flow rate per unit time of the liquid supplied to the nozzle, is calculated, and the second flow rate, which is the flow rate that changes as the driving frequency is adjusted by the pump control unit, matches the first flow rate at the timing. The value of the driving frequency, the number of rotations, or the elapsed time is calculated as the threshold.

(12) Also, in the liquid injection device, in addition to (11) above, the calculation unit calculates the value of the elapsed time at the timing when the second flow rate coincides with the first flow rate as the threshold, and the calculated The threshold of the rotation speed is calculated based on the threshold of the elapsed time and the rotation speed change rate, which is the rotation speed per unit time that changes as the driving frequency is adjusted by the pump control unit.

(13) In addition to the above (12), the liquid injection device has a plurality of rotation speed change rates that are different depending on the initial value of the rotation speed before the drive frequency starts to be adjusted by the pump control unit, It is provided with a memory unit that stores a plurality of rotations in a form connected to the initial value of the rotation speed, and the calculation unit selects a specific rotation speed change rate among the plurality of rotation speed change rates stored in the memory unit based on the initial value of the rotation speed. The rotation speed change rate is extracted, and the threshold value of the rotation speed is calculated based on the extracted rotation speed change rate.

According to the technology described herein, it is possible to suppress the increase in pressure of the liquid.

1 is a diagram showing the configuration of a supply path of a cleaning liquid in the cleaning device according to Embodiment 1.
Figure 2 is a block diagram showing the electrical configuration of a pump and valve provided in the cleaning device.
Figure 3 is a graph showing changes over time regarding the driving frequency of the inverter and the flow rate of the cleaning liquid in each cleaning liquid supply path.
Figure 4 is a graph showing changes over time in the pressure of the cleaning liquid in each cleaning liquid supply path.
Figure 5 is a block diagram showing the electrical configuration of a pump and valve provided in the cleaning device according to Embodiment 2.
Figure 6 is a graph showing changes over time in the pressure of the cleaning liquid and showing simulation results with five timings for closing the valve.
FIG. 7 is a graph showing changes over time in the pressure of the cleaning fluid, the flow rate of the cleaning fluid, the rotation speed of the electric motor, and the driving frequency of the inverter when the elapsed time is set to 1.8 sec in the simulation of FIG. 6.
Figure 8 is a graph showing changes over time regarding the number of rotations of an electric motor.

<Embodiment 1>

Embodiment 1 is explained with reference to FIGS. 1 to 4. In this embodiment, a cleaning device (liquid spray device) 10 that sprays a cleaning liquid as a liquid to clean an object to be cleaned is exemplified.

1 is a diagram showing the configuration of the cleaning liquid supply path in the cleaning device 10. As shown in FIG. 1, the cleaning device 10 according to the present embodiment is used in combination with a polishing device (PD) for polishing a semiconductor wafer, and the cleaning object is used in combination with a polishing pad (PA) for polishing a semiconductor wafer. It is done. The polishing pad PA provided in the polishing device PD combined with the cleaning device 10 according to the present embodiment is arranged in a pair so as to sandwich the semiconductor wafer to be polished from the top and bottom, and each pair is a semiconductor wafer. It is supported in a form that can rotate at high speed by a surface (platen) placed on the opposite side. Therefore, by using this polishing device PD, both the front and back sides of the semiconductor wafer can be polished simultaneously. As described above, a pair of polishing pads PA and a pair of surfaces supporting them constitute a polishing unit PO for polishing a semiconductor wafer in the polishing device PD. This polishing device (PD) is equipped with two polishing portions (PO) so that two semiconductor wafers can be polished at the same time.

As shown in FIG. 1, the cleaning device 10 combined with the polishing device PD of such a configuration includes a nozzle head ( 11), a pump 12 that pressurizes the cleaning liquid supplied from the cleaning liquid supply source and supplies it to the nozzle 11A, and the cleaning liquid is piped from the cleaning liquid supply source to the nozzle head 11 via the pump 12, etc. A supply path 13, a filter 14 disposed in the middle of the cleaning fluid supply path 13, a pressure sensor 15 disposed in the middle of the cleaning fluid supply path 13, and a filter 14 disposed in the middle of the cleaning fluid supply path 13. It is equipped with at least a branch portion (16) and a valve (17) disposed in the middle of the cleaning liquid supply passage (13). Among these, a total of four nozzle heads 11 are installed in pairs for each of the two polishing parts PO provided in the polishing device PD. In detail, four nozzle heads 11 are provided to individually correspond to the four polishing pads PA provided in each polishing unit PO, and each nozzle head 11 is positioned on the surface side with respect to each polishing pad PA. It is arranged to face the opposite side. Each nozzle head 11 has a plurality of nozzles 11A (for example, 6) that spray the cleaning liquid. A plurality of nozzles 11A are arranged in a row at approximately equal intervals on the nozzle head 11. The nozzle head 11 sprays the cleaning liquid from each nozzle 11A toward the polishing pad PA while being conveyed along the plate surface with respect to the polishing pad PA by the conveyance arm. Additionally, as a cleaning liquid, for example, ultrapure water or pure water can be used.

As shown in FIG. 1, the pump 12 is an inverter-motor driven type and includes a plunger 12A, etc. that pressurizes the cleaning liquid according to the rotational state of the electric motor 18 driven by the inverter 19, which will be described later. . That is, the pump 12 according to this embodiment is an electric plunger pump, which is a type of positive displacement pump. Specifically, this pump 12 is a triple plunger type with three plungers 12A, and each plunger 12A is connected to the power transmitted from the electric motor 18 through a coupling and crank, etc. Based on the reciprocating motion, the cleaning liquid can be pressurized by generating a volume change in the pressurizing part where the cleaning liquid is present. According to the pump 12 of such an inverter/motor drive type, the flow rate of the pressurized cleaning liquid can be set to, for example, the range of 8.5 L/min to 17 L/min, and the flow rate of the cleaning liquid is set to about 6 L/min or less. Compared to existing air-driven pumps, it is suitable for increasing the flow rate of cleaning liquid. Additionally, according to the inverter/motor driven pump 12, the pressure of the pressurized cleaning liquid can be set to a range of, for example, 4 MPa to 15 MPa.

The cleaning liquid supply path 13 is made of a high-pressure hose that can sufficiently withstand the flow of pressurized cleaning liquid. As shown in FIG. 1, the cleaning liquid supply path 13 is branched from the cleaning liquid supply source to the nozzle head 11 by a branch 16 made of a joint, etc., and is branched from the cleaning liquid supply source to the nozzle head 11. It includes a common cleaning liquid supply path 13A piped to the branch portion 16, and a plurality of individual cleaning fluid supply paths 13B piped from the branch portion 16 to each nozzle head 11. The common cleaning liquid supply path 13A is one through which the cleaning liquid supplied to all nozzle heads 11 is commonly distributed. The above-mentioned pump 12 is installed in the middle of the common cleaning liquid supply path 13A, and in addition, a filter 14, a pressure sensor 15, etc. are installed. The filter 14 serves to prevent clogging of the nozzle 11A by filtering contamination contained in the cleaning liquid. The pressure sensor 15 can measure the differential pressure between the inlet and outlet of the filter 14 and output the pressure loss in the filter 14. Additionally, the filter 14 and the pressure sensor 15 may be installed in the middle of the individual cleaning liquid supply path 13B described below. The number of individual cleaning liquid supply channels 13B is equal to the number of nozzle heads 11 (4), and the cleaning liquid supplied to each nozzle head 11 is distributed individually. A valve 17 is installed in the middle of each individual cleaning liquid supply path 13B. The valves 17 are installed in the same number (4) as the number of nozzle heads 11 and the individual cleaning liquid supply channels 13B, and the distribution of the cleaning liquid can be controlled by opening and closing the individual cleaning liquid supply channels 13B. there is. The valve 17 is comprised of, for example, an electromagnetic valve, and the open/closed state is electrically controlled by the valve control unit 21, which will be described later. In this embodiment, the valve 17 is exemplified as a spring return type that is always kept in a closed state. The cleaning liquid supplied from the supply source is pressurized by the pump 12 while distributing through the common cleaning liquid supply path 13A, is filtered by the filter 14, and then passes through the branch portion 16 to each individual cleaning fluid supply path 13B. is distributed to Then, if the cleaning liquid contains an open state in each valve 17, it is allowed to flow through the individual cleaning liquid supply path 13B in which the valve 17 in the open state is installed, and reaches the nozzle head 11. It is sprayed from a nozzle 11A provided on the nozzle head 11. In addition, in the case where the valve 17 in the closed state is included, the cleaning liquid does not flow through the individual cleaning liquid supply path 13B where the valve 17 in the closed state is installed, and the individual cleaning liquid supply path 13B through which the cleaning liquid does not circulate ), the cleaning liquid is not sprayed from each nozzle 11A of the nozzle head 11 installed.

The electrical configuration of the pump 12 and the valve 17 will be described with reference to FIG. 2. FIG. 2 is a block diagram showing the electrical configuration of the pump 12 and valve 17 provided in the cleaning device 10. As shown in FIG. 2, the cleaning device 10 includes an electric motor 18 that drives a pump 12 that is driven by an inverter motor, and an inverter 19 that rotates the electric motor 18. , It is equipped with at least a pump control unit 20 that adjusts the driving frequency of the inverter 19 and a valve control unit 21 that controls the opening and closing of the valve 17. The electric motor 18 is driven to rotate based on the alternating current supplied by the inverter 19, and its rotational force is used as a power for the reciprocating movement of the plunger 12A through a coupling, a crank, etc. The inverter 19 converts the alternating current supplied from the alternating current power supply into alternating current of a predetermined frequency and supplies it to the electric motor 18, thereby rotating the electric motor 18 at a predetermined rotational speed. The inverter 19 can arbitrarily change the frequency of the alternating current supplied to the electric motor 18, thereby adjusting the rotation speed of the electric motor 18. Additionally, the inverter 19 can arbitrarily change the voltage in addition to the frequency of the alternating current supplied to the electric motor 18. The pump control unit 20 can adjust the driving frequency of the inverter 19 by outputting a signal to the inverter 19, thereby controlling the rotational state (rotation speed) of the electric motor 18. The pump control unit 20 outputs a signal for controlling the driving of the inverter 19 based on signals output from the pressure sensor 15 or the valve control unit 21 described below.

As shown in FIG. 2 , the valve control unit 21 controls the opening and closing of the plurality of valves 17 based on the spray signal (signal) output from the polishing device PD. In detail, the timing for starting and stopping high-pressure cleaning by the cleaning device 10 needs to be suitable for the operating state of the polishing device PD, so the polishing device PD is connected to the cleaning device 10. A spray signal is output to start and stop high-pressure cleaning. When a spray signal is output from the polishing device PD, the valve control unit 21 opens and closes the four valves 17 appropriately, thereby controlling the nozzle ( 11A), the cleaning liquid is selectively sprayed and the spraying of the cleaning liquid is stopped in the nozzles 11A of the remaining nozzle heads 11, the cleaning liquid is sprayed from the nozzles 11A of all nozzle heads 11, or all nozzle heads 11 are sprayed. Jetting of the cleaning liquid from the nozzle 11A of the head 11 can be stopped. In this embodiment, since the valve 17 is of a type that is always closed, the valve control unit 21 outputs an open signal when opening the valve 17 in the closed state, and opens the valve in the open state ( When closing 17), the opening and closing of the valve 17 is controlled by stopping the output of the open signal. In addition, hereinafter, when distinguishing between the four valves 17, the first valve is installed in the individual cleaning liquid supply path 13B piped to the pair of nozzle heads 11 installed corresponding to one polishing unit PO. The valve 17α and the second valve 17β are installed in the individual cleaning liquid supply path 13B piped to the pair of nozzle heads 11 provided corresponding to the other polishing section PO, and the third valve is (17γ) and the fourth valve (17σ).

Here, if the pump is an air-driven type, an air cylinder with compressed air inside, a material cylinder with cleaning liquid inside, one end connected to the air cylinder and the other end connected to the material cylinder, move forward and backward. Given the configuration having a piston rod, the pressure applied to the cleaning liquid is calculated by multiplying the air pressure of the compressed air by the ratio of the piston diameter on the air cylinder side of the piston rod and the piston diameter on the material cylinder side. becomes static pressure. Accordingly, even when the open valve is closed by the valve control unit, a situation in which the pressure of the cleaning liquid rises above the above-described static pressure is avoided. On the other hand, in the inverter-motor driven pump 12 like this embodiment, the cleaning liquid is pressurized by the plunger 12A that reciprocates with the rotation of the electric motor 18, so the plunger 12A ), if the valve 17 that was opened by the valve control unit 21 is closed during the operation, the pressure of the cleaning fluid may rise rapidly and may exceed the internal pressure of the cleaning fluid supply path 13.

In that respect, the valve control unit 21 provided in the cleaning device 10 according to the present embodiment outputs a signal at least when the valve 17 is closed, as shown in FIG. 2, and the pump control unit 20 Controls the operation of the pump 12 to relieve the degree of pressurization of the cleaning liquid based on the signal output from the valve control unit 21. In detail, the valve control unit 21 is capable of outputting a signal according to the opening and closing of the valve 17, especially when closing the valve 17 (the number of valves 17 to be opened is reduced and the valve to be closed ( When the number 17) increases, a frequency switching signal (frequency reduction signal) is output as a signal to the pump control unit 20. And, the pump control unit 20 controls the rotational state of the electric motor 18 by adjusting the driving frequency of the inverter 19 based on the signal output from the valve control unit 21. In particular, the pump control unit 20 controls the rotational state of the electric motor 18. When a frequency switching signal is output, the driving frequency of the inverter 19 is reduced based on the frequency switching signal, and the rotation speed of the electric motor 18 is reduced accordingly, and is applied to the cleaning liquid through the plunger 12A. The pressure is reduced. In this way, even when the valve 17 is closed during the operation of the plunger 12A, a sudden increase in the pressure of the cleaning liquid that may occur due to the closing of the valve 17 can be suppressed, and the It becomes difficult for situations such as exceeding the internal pressure to occur.

Next, the detailed timing of control related to the pump 12 and the valve 17 by the pump control unit 20 and the valve control unit 21 will be explained with reference to FIGS. 3 and 4. Specifically, from a state in which four polishing pads PA are being cleaned in two polishing portions PO provided in the polishing device PD, one polishing portion PO is cleaned with two polishing pads ( Assuming that the cleaning of PA) is continued, but the cleaning of the two polishing pads PA in the other polishing unit PO is finished, the pump control unit 20 and the valve control unit 21 The case of controlling the pump 12 and valve 17 will be described. FIG. 3 is a graph showing changes over time regarding the driving frequency of the inverter 19 and the flow rate of the cleaning fluid in the individual cleaning fluid supply passages 13B (the flow rate of the cleaning fluid per one nozzle 11A). While the solid line graph shown in FIG. 3 shows the change over time regarding the flow rate of the cleaning liquid in the individual cleaning liquid supply path 13B, the dashed-dotted line graph shown in FIG. 3 shows the change over time regarding the driving frequency of the inverter 19. It indicates the changes that followed. Fig. 4 is a graph showing changes over time regarding the pressure of the cleaning liquid (jet pressure of the cleaning liquid sprayed from the nozzle 11A) in the individual cleaning liquid supply passages 13B. The horizontal axes in FIGS. 3 and 4 both represent the elapsed time (unit: “sec”) after the spray signal is output from the polishing device PD, and 1 division corresponds to 1 sec. The left vertical axis in FIG. 3 represents the driving frequency (unit: “Hz”) of the inverter 19, and the right vertical axis in FIG. 3 represents the flow rate of the cleaning liquid (unit: “L/min”). The vertical axis in FIG. 4 represents the pressure of the cleaning liquid (unit: “MPa”).

First, at time T ₀ (start time of switching of the driving frequency) on each horizontal axis of FIGS. 3 and 4, a spray signal is output from the polishing device PD. This spray signal is sent to the valve control unit 21 by sending two valves 17 (for example, the first valve 17α and the second valve 17β) out of the four valves 17 in the open state, and the second valve 17β. One of the third valves 17γ and the fourth valve 17σ) is kept open, but the remaining two valves 17 (e.g., the first valve 17α and the second valve 17β, and the second valve 17β) are kept open. This is to close the other of the three valves 17γ and the fourth valve 17σ. Then, before closing the valve 17, the valve control unit 21 outputs a frequency switching signal (frequency adjustment signal) to the pump control unit 20 based on the spray signal described above. The pump control unit 20 starts switching (adjusting) the driving frequency of the inverter 19 based on the frequency switching signal output from the valve control unit 21. Specifically, the pump control unit 20 changes the driving frequency of the inverter 19, which is about 72 Hz in the state before switching (when the four valves 17 are open), to about 36 Hz, that is, based on the frequency switching signal. Convert to about half of what it was before conversion. The ratio of the driving frequency of the inverter 19 before and after switching coincides with the ratio of the number of valves 17 in the open state before and after switching. It is difficult to switch the driving frequency of the inverter 19 instantly, and the switching requires a certain amount of time. Specifically, when switching of the driving frequency of the inverter 19 is started by the pump control unit 20 at time T ₀ , the driving frequency changes to gradually decrease continuously over time, as shown in FIG. 3. , When a predetermined time (for example, about 3 sec) has elapsed and the time point T ₂ (the driving frequency switching end point) is reached, the target value (about 36 Hz) is reached. In this way, as the driving frequency of the inverter 19 decreases, the rotation speed of the electric motor 18 decreases and the pressure applied to the cleaning liquid through the plunger 12A decreases.

And, as shown in FIGS. 3 and 4, the valve control unit 21 operates two of the four valves 17 at the time T ₁ (valve closing time) between the time T ₀ and the time T ₂ described above. The valve (17) is being abolished. That is, the valve control unit 21 operates based on the frequency conversion signal at a timing later than time T ₀ , which is the timing at which the driving frequency of the inverter 19 begins to be adjusted by the pump control unit 20 based on the frequency conversion signal. The valve 17 is closed at a timing prior to time T ₂ , which is the timing at which the adjustment of the driving frequency of the inverter 19 by the pump control unit 20 ends. Here, if the valve 17 is closed by the valve control unit at time T ₀ , the driving frequency of the inverter 19 has not yet decreased substantially, so there is a short period of time until the driving frequency is sufficiently reduced. Although it is time, there is a risk that the pressure of the cleaning liquid will rise rapidly due to the closing of the valve 17. In that regard, since the valve 17 is closed by the valve control unit 21 later than the time point T ₀ as described above, the valve 17 is closed no matter how much time it takes to switch the driving frequency of the inverter 19. At the time point T ₁ , the driving frequency of the inverter 19 has been sufficiently reduced. Therefore, it is difficult for a sudden increase (overshoot) in the pressure of the cleaning liquid due to closing of the valve 17 to occur. Specifically, as shown in FIG. 4, the pressure of the cleaning fluid is suppressed to a maximum of about 15 MPa even if it increases as the valve 17 is closed, and it never reaches the upper limit of 20 MPa, which is the upper limit related to the allowable pressure of the cleaning fluid. . Also, if the valve 17 is closed by the valve control unit at time T ₂ , the pressure drop of the cleaning liquid due to the decrease in the driving frequency of the inverter 19 becomes excessive, and the valve 17 in the open state is connected. There is a risk that the injection pressure of the cleaning liquid from the nozzle 11A may decrease significantly, and the time required to switch the spraying state of the cleaning liquid from each nozzle 11A tends to take excessively as the valve 17 is closed. There is. In contrast, since the valve 17 is closed by the valve control unit 21 before time T ₂ as described above, an excessive decrease in the pressure of the cleaning liquid due to reducing the driving frequency of the inverter 19 is suppressed. The injection pressure of the cleaning liquid from the nozzle 11A connected to the valve 17 in the open state can be sufficiently maintained, and the injection state of the cleaning liquid from each nozzle 11A can be switched by closing the valve 17. The time required is shortened. In particular, the timing at which the valve 17 is closed by the valve control unit 21 is, as shown in FIG. 4, before the pressure of the cleaning liquid, which decreases as the driving frequency of the inverter 19 decreases, becomes 0 (specifically, is a value greater than 6 MPa), so it is possible to avoid an emergency stop of the cleaning device 10 that occurs when the pressure of the cleaning fluid becomes 0, and also prevents a sudden drop in the pressure of the cleaning fluid due to closing of the valve 17. This can make it difficult to generate an increase.

In addition, as shown in FIGS. 3 and 4, the valve control unit 21 switches the valve from time T ₀ , which is the timing at which switching of the driving frequency of the inverter 19 is started by the pump control unit 20 based on the frequency switching signal. The time until the time point T ₁ which is the timing for closing the valve 17 is the time point T ₁ which is the timing for closing the valve 17. The switching of the drive frequency of the inverter 19 by the pump control unit 20 is completed, and the cleaning liquid The valve 17 is closed so that it is longer than the time until the time point T ₂ , which is the timing at which the fluctuation of pressure ends. Specifically, while the time from the above-mentioned time T ₀ to the time T ₁ is approximately 2 sec, the time from the time T ₁ to the time T ₂ is approximately 1 sec. Therefore, the time (approximately 2 sec) from time T ₀ to time T ₁ ends from time T ₀ to time T ₂ (after the start of switching of the driving frequency of the inverter 19, and the time of the pressure of the cleaning liquid The proportion (approximately 66.7%) of the time until the change ends (approximately 3 sec) is sufficiently large, which makes it more difficult for a sudden increase in the pressure of the cleaning fluid due to closure of the valve 17 to occur. As the above-mentioned ratio increases, the rapid increase in the pressure of the cleaning liquid due to closing of the valve 17 tends to be suppressed more appropriately. As a result of the above, the maximum instantaneous pressure (peak pressure) related to the pressure of the cleaning liquid that rises when the valve 17 is closed is suppressed to about 15 MPa. As a result, the maximum instantaneous pressure related to the pressure of the cleaning liquid that rises when the valve 17 is closed is adjusted to within the specified pressure value according to each specification that varies depending on the product. On the other hand, the proportion (about 33.3%) of the time from time T ₁ to time T ₂ (about 1 sec) to the time from time T ₀ to time T ₂ (about 3 sec) is sufficiently small, As a result, the time required to switch the spraying state of the cleaning liquid from each nozzle 11A by closing the valve 17 is further shortened. As described above, in order to keep the maximum instantaneous pressure related to the pressure of the cleaning liquid that rises when the valve 17 is closed within the specified pressure value according to each specification that varies depending on the product, from time point T ₀ to time T ₁ It is effective to appropriately control the time or the time from time point T ₁ to time T ₂ .

In the explanation so far, the case where the valve control unit 21 closes two valves 17 out of the four valves 17 in the open state before switching has been exemplified, but the valves in the open state before switching ( It is possible to change the number of valves 17) and the number of valves 17 to be closed as appropriate. For example, the number of valves 17 in the open state before switching may be four, and all valves 17 may be closed by the valve control unit 21. In this way, when the four valves 17 are closed, the valve control unit 21 determines the timing of closing the valves 17 and the timing at which the pump control unit 20 starts switching the driving frequency of the inverter 19. From the following viewpoint, it is preferable that the time difference between timings be larger than the time difference (about 2 sec) in the case of closing the two valves 17. That is, as the number of valves 17 that are closed increases and the number of nozzles 11A from which spraying of the cleaning fluid is stopped increases, the pressure of the cleaning fluid due to the closing of the valves 17 tends to rise more rapidly. . On the other hand, as the number of valves 17 to be closed increases, the time difference between the timing of closing the valve 17 and the timing at which the pump control unit 20 starts switching the driving frequency of the inverter 19 increases. In this way, sufficient time can be taken to switch the driving frequency of the inverter 19, and a sudden increase in pressure due to closing of the valve 17 can be more appropriately suppressed. In addition, when the number of valves 17 closed by the valve control unit 21 is three, the time difference described above is made smaller than when the number of valves 17 closed is four, and the number of valves 17 closed is two. Just make it larger than usual. In addition, when the number of valves 17 closed by the valve control unit 21 is one, the above-described time difference may be made smaller than when the number of valves 17 closed is two.

As explained above, the cleaning device (liquid spray device) 10 of the present embodiment includes a nozzle 11A that sprays a cleaning liquid (liquid), and is connected to the nozzle 11A and pressurizes the cleaning liquid to spray the nozzle 11A. A valve 17 that is installed between the supply pump 12 and the nozzle 11A and the pump 12 to control the distribution of the cleaning liquid by opening and closing, and a valve control unit 21 that controls the opening and closing of the valve 17. , at least a valve control unit 21 that outputs and controls a frequency switching signal (signal) when closing the valve 17, and a pump control unit 20 that controls the operation of the pump 12, based on the frequency switching signal. It is equipped with a pump control unit 20 that controls the operation of the pump 12 to relieve the degree of pressurization with the cleaning liquid.

In this way, the cleaning liquid pressurized by the pump 12, the operation of which is controlled by the pump control unit 20, is sprayed from the nozzle 11A. The opening and closing of the valve 17 installed between the nozzle 11A and the pump 12 is controlled by the valve control unit 21, and the distribution of the cleaning liquid is controlled accordingly. In addition, the valve control unit 21 outputs a frequency switching signal at least as the valve 17 is closed, while the pump control unit 20 switches the frequency output as the valve 17 is closed from the valve control unit 21. Based on the signal, the pump 12 is driven to relieve the degree of pressurization of the cleaning liquid. This can suppress a sudden increase in the pressure of the cleaning liquid that may occur when the valve 17 is closed.

In addition, it is equipped with an electric motor 18 that drives the pump 12 and an inverter 19 that rotates the electric motor 18, and the pump 12 pressurizes the cleaning liquid according to the rotation state of the electric motor 18. The pump control unit 20 controls the rotational state of the electric motor 18 by adjusting the driving frequency of the inverter 19. In this way, the rotational state of the electric motor 18 is controlled by adjusting the driving frequency of the inverter 19 by the pump control unit 20, and the cleaning solution by the plunger 12A according to the rotational state of the electric motor 18 The degree of pressurization is controlled. Such an inverter-motor driven pump 12 is suitable for increasing the flow rate of the cleaning liquid supplied to the nozzle 11A compared to, for example, the air driven pump 12. . On the other hand, in the inverter/motor driven pump 12, the pressure of the cleaning liquid tends to rise rapidly when the valve 17 is closed, but the pump control unit 20 controls the valve ( By abolishing 17), the driving frequency of the inverter 19 is reduced based on the output frequency switching signal, thereby lowering the rotation speed of the electric motor 18. As a result, the degree of pressurization of the cleaning liquid by the plunger 12A of the pump 12 can be relaxed, thereby suppressing a sudden increase in the pressure of the cleaning liquid.

Additionally, the valve control unit 21 closes the valve 17 later than the timing at which the driving frequency of the inverter 19 begins to be adjusted by the pump control unit 20 based on the frequency switching signal. In the inverter-motor driven pump 12 as described above, it takes some time to adjust the driving frequency of the inverter 19 by the pump control unit 20, so if the pump control unit 20 If the valve control unit closes the valve 17 at the timing when the drive frequency of (19) begins to be adjusted, there is a risk that the pressure of the cleaning liquid will rise rapidly, albeit for a short period of time. In that regard, by closing the valve 17 by the valve control unit 21 later than the timing at which the driving frequency of the inverter 19 begins to be adjusted by the pump control unit 20 based on the frequency switching signal as described above, No matter how long it takes to adjust the driving frequency of the inverter 19, it becomes difficult for a sudden increase in the pressure of the cleaning fluid due to closing the valve 17 to occur.

Additionally, the valve control unit 21 closes the valve 17 before the timing at which adjustment of the driving frequency of the inverter 19 by the pump control unit 20 ends based on the frequency switching signal. In this way, the driving frequency of the inverter 19 is reduced compared to the case where the valve 17 is closed by the valve control unit at the timing when the adjustment of the driving frequency of the inverter 19 by the pump control unit 20 ends. In addition to suppressing an excessive drop in the pressure of the cleaning liquid due to the closing of the valve 17, the time required to switch the spraying state of the cleaning liquid from the nozzle 11A due to the closing of the valve 17 is shortened.

In addition, the valve control unit 21 determines that the time from the timing at which the driving frequency of the inverter 19 begins to be adjusted by the pump control unit 20 based on the frequency switching signal to the timing at which the valve 17 is closed is determined by the valve 17 The valve 17 is closed so that it is longer than the time from the timing of closing ) to the timing at which the adjustment of the driving frequency of the inverter 19 by the pump control unit 20 ends. In this way, the time from when the driving frequency of the inverter 19 begins to be adjusted by the pump control unit 20 based on the frequency switching signal until the valve 17 is closed is the driving time of the inverter 19. Since the proportion of the time required to adjust the frequency is sufficiently large, it becomes more difficult for a sudden increase in the pressure of the cleaning fluid due to closing the valve 17 to occur. As a result, the maximum instantaneous pressure related to the pressure of the cleaning liquid that rises when the valve 17 is closed is adjusted to within the specified pressure value according to each specification that varies depending on the product. In addition, the time from when the valve 17 is closed until the adjustment of the driving frequency of the inverter 19 by the pump control unit 20 ends and the change in the pressure of the cleaning liquid ends is the driving frequency of the inverter 19. Since the proportion of the time required for adjustment is sufficiently small, the time required to switch the spraying state of the cleaning liquid from the nozzle 11A due to closing the valve 17 is further shortened.

In addition, a plurality of nozzles 11A and valves 17 are provided, and the valve control unit 21 adjusts the timing for closing the valve 17 and the driving frequency of the inverter 19 by the pump control unit 20. The time difference between the starting timings is increased as the number of nozzles 11A from which spraying of the cleaning liquid is stopped due to closing of the valve 17 increases. Comparing the case where the number of nozzles 11A where the spraying of the cleaning liquid is stopped due to the closing of the valve 17 is large and the case where the number of nozzles 11A where the spraying of the cleaning liquid is stopped due to the closing of the valve 17 is small, In the former case, the pressure of the cleaning liquid due to closing of the valve 17 tends to rise more rapidly than in the latter case. At that point, the valve control unit 21 determines the time difference between the timing at which the valve 17 is closed and the timing at which the driving frequency of the inverter 19 begins to be adjusted by the pump control unit 20. It varies depending on the number of nozzles 11A from which the spraying of the cleaning liquid is stopped due to closure, and the above-described time difference increases as the number of nozzles 11A from which the spraying of the cleaning liquid stops increases, so the driving of the inverter 19 Sufficient time can be taken to adjust the frequency, and a sudden increase in pressure due to closing of the valve 17 can be more appropriately suppressed.

Additionally, the valve control unit 21 closes the valve 17 at a timing before the pressure of the cleaning liquid, which decreases as the driving frequency of the inverter 19 is adjusted based on the frequency switching signal, reaches zero. If the pressure of the cleaning liquid becomes 0, there is a risk that the cleaning device 10 may come to an emergency stop. In that regard, as described above, the valve control unit 21 closes the valve 17 at a timing before the pressure of the cleaning liquid, which decreases as the driving frequency of the inverter 19 is adjusted based on the frequency switching signal, reaches 0. Therefore, it is possible to avoid an emergency stop of the cleaning device 10 and make it difficult to cause a sudden increase in the pressure of the cleaning liquid due to closing the valve 17.

<Embodiment 2>

Embodiment 2 is explained with reference to FIGS. 5 to 8. This Embodiment 2 shows a case where control, etc. related to the valve 117 by the valve control unit 121 is changed. Additionally, overlapping descriptions of the structure, action, and effects similar to those of Embodiment 1 described above will be omitted.

As shown in FIG. 5, the cleaning device 110 according to this embodiment is equipped with a memory section 22 in which data referenced by the valve control section 121 is stored. The data stored in the memory unit 22 will be explained in detail later. The driving frequency of the inverter 119 is fed back to the valve control unit 121, and the rotation speed of the electric motor 118 is fed back. The rotation speed of the electric motor 118 may be measured with a rotation meter, or may be automatically calculated by the valve control unit 121. In addition, in the valve control unit 121, the pressure (water pressure) of the cleaning liquid present in the cleaning liquid supply path 13 (see FIG. 1), which is the path from the pump 112 to the nozzle 11A, is fed back by the pressure sensor 115. It is supposed to be possible.

The valve control unit 121 performs control related to the valve 117 by appropriately using the data of the memory unit 22, the driving frequency of the inverter 119, the rotation speed of the electric motor 118, and the pressure of the cleaning liquid. . That is, when closing the open valve 117, the valve control unit 121 selects the data of the memory unit 22, the driving frequency of the inverter 119, the rotation speed of the electric motor 118, and the pressure of the cleaning liquid. The timing for closing the valve 117 is determined based on at least one factor. Specifically, after the driving frequency of the inverter 119 begins to be adjusted by the pump control unit 120, the valve control unit 121 adjusts the driving frequency, the number of rotations per unit time of the electric motor 118, or the elapsed time. When the threshold is reached, the valve 117 is closed. The valve control unit 121 may close the valve 117 when the elapsed time reaches the threshold after the driving frequency begins to be adjusted by the pump control unit 120. However, when the driving frequency or rotation speed reaches the threshold, the valve 117 may be closed. may be abolished. In addition, the cleaning device 110 is equipped with a calculation unit 23 that calculates a threshold value based on operating conditions related to the operation of at least one of the valve 117, the electric motor 118, and the inverter 119. The calculation unit 23 calculates the threshold based on the number of valves 117 closed by the valve control unit 121, and as the number of valves 117 closed by the valve control unit 121 increases, the driving frequency or The threshold related to the number of rotations may be decreased, and the threshold related to the elapsed time may be increased.

In order to examine how to make the above-mentioned calculation unit 23 calculate the threshold, a simulation regarding the timing of closing the valve 117 was performed. The simulation will be described with reference to FIG. 6. Figure 6 is a graph showing the change over time in the pressure of the cleaning liquid, and shows simulation results with five timings for closing the valve 117. In this simulation, the elapsed times from the time T ₀ at which the switching of the driving frequency starts until the valve 117 is closed were set to five types: 1.6 sec, 1.8 sec, 2 sec, 2.6 sec, and 3 sec, respectively. The horizontal axis in FIG. 6 represents time (unit: “sec”), and 1 division corresponds to 1 sec. The horizontal axis of FIG. 6 indicates the time point T ₀ at which the switching of the driving frequency begins and the time point T ₂ at which the switching of the driving frequency ends. The vertical axis in FIG. 6 represents the pressure of the cleaning liquid (unit: “MPa”), and one division corresponds to 0.5 MPa. In addition, in this simulation, four valves 117 were opened, two valves 117 were closed, and the remaining two valves 117 were kept open. Additionally, the driving frequency of the inverter 119 is set to 64 Hz at time T ₀ and is changed to 32.3 Hz from there. In addition, the total flow rate of the cleaning liquid per unit time (the sum of the flow rate per valve 117 multiplied by the number of open valves 117) is at the time point T ₀ when the four valves 117 are open. It is set at 18 L/min, and at the point in time T ₂ when the two valves 117 are open, it is set at 9 L/min. That is, the flow rate per unit time (flow rate per valve 117) of the cleaning liquid supplied to the nozzle 11A through one open valve 117 is 4.5 L/min. Additionally, the pressure of the cleaning liquid is maintained at the standard value of 10 MPa.

The results of the simulation are explained. According to FIG. 6, when the elapsed time from the start of switching of the driving frequency until the valve 117 is closed is 1.6 sec, the pressure of the cleaning liquid temporarily reaches the reference value of 10 MPa as the valve 117 is closed. exceeded and reached 11 MPa. That is, it was found that when the elapsed time was 1.6 sec, a sudden increase (overshoot) in the pressure of the cleaning liquid occurred due to the closing of the valve 117. On the other hand, when the elapsed time was set to 1.8 sec, 2 sec, 2.6 sec, and 3 sec, it was possible to avoid the pressure of the cleaning liquid temporarily exceeding 10 MPa (overshoot). Among these, the case where the elapsed time is set to 1.8 sec, which is the shortest, is preferable from the following viewpoint. That is, if the elapsed time is set to 1.8 sec, the pressure drop of the cleaning liquid due to reducing the driving frequency of the inverter 119 is most suppressed, and the spraying of the cleaning liquid from each nozzle 11A is achieved by closing the valve 117. The time required to switch states is shortened the most. Additionally, if the elapsed time is shorter than 1.8 sec, there is concern that an overshoot of the pressure of the cleaning liquid may occur.

According to the results of the above simulation, setting the elapsed time from the start of the drive frequency change until the valve 117 is closed to 1.8 seconds suppresses a decrease in the pressure of the cleaning fluid and switches the spraying state of the cleaning fluid. It was found that it was most desirable to shorten the time required. However, depending on the usage conditions of the cleaning device 110, there is a risk that the pressure of the cleaning liquid may overshoot even if the elapsed time is 1.8 seconds. The above-mentioned “conditions for use of the cleaning device 110” include, for example, the driving frequency of the inverter 119 just before switching, the rotational speed of the electric motor 118, the pump 112, and the electric motor 118. ) capabilities (for example, the maximum driving frequency or maximum rotation speed allowed by specifications, etc.), the number of nozzles 11A provided in one nozzle head 11, etc. Therefore, regardless of the usage conditions of the cleaning device 110, general conditions that can avoid overshoot of the pressure of the cleaning liquid from occurring were considered as follows. In other words, the overshoot of the pressure of the cleaning fluid is the flow rate of the cleaning fluid existing in the path from the pump 112 to the nozzle 11A at the time when the valve 117 is closed, and the time T when the switching of the driving frequency ends. ₂ , it is thought that this occurs when the flow rate of the cleaning liquid existing in the path from the pump 112 to the nozzle 11A is greater than that.

Subsequently, the total flow rate and pressure of the cleaning liquid were verified. In this verification, the total flow rate and pressure of the cleaning liquid were calculated based on the rotation speed of the electric motor 118. The results are shown in Figure 7. Figure 7 shows the pressure of the cleaning fluid, the total flow rate of the cleaning fluid, the rotation speed of the electric motor 118, and the driving frequency of the inverter 119 according to time in the case where the elapsed time is 1.8 sec in the above simulation. This is a graph showing change. The horizontal axis in FIG. 7 represents time (unit: “sec”), and 1 division corresponds to 1 sec. The horizontal axis of FIG. 7 indicates a time point T ₀ at which the switching of the driving frequency begins, a time point T ₁ at which the valve 117 is closed, and a time point T ₂ at which the switching of the driving frequency ends. The vertical axis in FIG. 7 represents the pressure of the cleaning fluid (unit: “MPa”), the total flow rate of the cleaning fluid per unit time (unit: “L/min”), the number of revolutions of the electric motor 118 (unit: “rps”), and the inverter. Indicates the driving frequency of (119). On the vertical axis of Fig. 7, one division corresponds to 1 MPa, 1 L/min, and 1 rps. In FIG. 7 , with respect to the pressure of the cleaning liquid, the measured value (actual value) using a rotation meter and the calculated value (predicted value) calculated based on the rotation speed of the electric motor 118 are respectively indicated by solid lines. The calculated pressure of the cleaning liquid is a value when the valve 117 is not closed, and is calculated based on the rotation speed of the electric motor 118, etc.

Specifically, the flow rate and pressure of the cleaning liquid at a certain point in time (originally) are set to “L ₀ ” and “P ₀ ,” respectively, and the flow rate and pressure of the cleaning liquid at a later point in time are set to “L ₁ ” and “P, respectively. When set to _"1 ", the following equation (1) is obtained. In addition, while the flow rate L ₀ and the pressure P ₀ are known values obtained by actual measurement or calculation, the flow rate L ₁ and the pressure P ₁ are predicted values obtained by calculation. On the other hand, when the rotational speed of the electric motor 118 at a later point in time is set to "r" and the intrinsic coefficient according to the capability of the pump 112 is set to "C", the following equation (2) is obtained: Lose. The intrinsic coefficient C of the pump 112 is the ratio of the driving frequency of the inverter 119 divided by the flow rate of the cleaning liquid. In addition, the unique coefficient C of the pump 112 can be said to be a ratio obtained by dividing the number of revolutions of the electric motor 118 by the flow rate of the cleaning liquid and then dividing it by 10. By substituting the right side of equation (1) for the flow rate L ₁ in equation (2) and modifying it, the following equation (3) is obtained. By using equation (3), the pressure P ₁ at a later point in time, that is, the predicted value of the pressure, can be calculated. Additionally, the specific value of the intrinsic coefficient C of the pump 112 according to the present embodiment is, for example, 3.51, but this value varies depending on the capability of the pump 112. Additionally, the total flow rate of the cleaning liquid shown in FIG. 7 is a calculated value (predicted value) calculated based on the rotation speed of the electric motor 118. In FIG. 7, the data displayed as a solid line related to the total flow rate of the cleaning fluid represents the case where the valve 117 is closed at a timing of an elapsed time of 1.8 sec, and the data displayed as a two-dashed line related to the total flow rate of the cleaning fluid. represents the case where the valve 117 is not closed.

[Formula 1]

[Formula 2]

[Formula 3]

The results in FIG. 7 will be explained. According to FIG. 7, it was found that the total flow rate of the cleaning liquid decreased (changed) at a rate higher than the driving frequency of the inverter 119 and the rotation speed of the electric motor 118. In other words, before T ₂ when the conversion of the driving frequency of the inverter 119 ends (the point at which the driving frequency reaches the target value), the total flow rate of the cleaning liquid reaches the target value after the conversion (9 L/min). I was able to. On the other hand, it was found that the calculated value of the pressure of the cleaning liquid decreased (changed) at a higher rate of change than the measured value (refer to the pressure during the period from time T ₀ to time T ₁ ). It was also found that the calculated value of the pressure of the cleaning liquid decreased at a rate of change higher than the driving frequency of the inverter 119 and the rotation speed of the electric motor 118.

Based on the above verification results, the calculation unit 23 according to the present embodiment determines the nozzle 11A from the pump 112 after the adjustment of the drive frequency by the pump control unit 120 is completed (after time point T ₂ ). ) calculates the first flow rate, which is the flow rate per unit time of the cleaning liquid supplied to the pump, and the second flow rate, which is the flow rate that changes as the driving frequency is adjusted by the pump control unit 120, is the driving frequency at the timing when it matches the first flow rate, The value of rotation speed or elapsed time is calculated as a threshold value. The first flow rate calculated by the calculation unit 23 can be said to be a target value of the flow rate (9 L/min in the verification in FIG. 7) that changes as the driving frequency is adjusted by the pump control unit 120. Here, the rate of change of the flow rate and pressure of the cleaning liquid is higher than the rate of change of the driving frequency of the inverter 119 and the rotation speed of the electric motor 118, as shown in the verification result described in the previous paragraph (see FIG. 7). So, the calculating unit 23 calculates the first flow rate, which is the target value, and then calculates the driving frequency at the timing when the second flow rate, which is a flow rate that changes as the driving frequency is adjusted by the pump control unit 120, matches the first flow rate. , the number of revolutions or the value of elapsed time is calculated as a threshold. When the valve control unit 120 closes the valve 117 based on the threshold value calculated in this way, the certainty of avoiding a situation where the second flow rate becomes greater than the first flow rate at the timing when the valve 117 is closed increases. . This increases the certainty that overshoot of the pressure of the cleaning liquid that may occur when the valve 117 is closed is suppressed.

In addition, the calculation unit 23 calculates the value of the elapsed time at the timing when the above-described second flow rate coincides with the first flow rate as a threshold, and determines the drive frequency by the calculated elapsed time threshold and the pump control unit 120. The rotation speed threshold is calculated based on the rotation speed change rate, which is the rotation speed of the electric motor 118 per unit time (1 sec), which changes as is adjusted. Here, the set pressure is set to “P”, the number of valves opened before switching is set to “n”, the number of valves 117 opened after switching is set to “m”, and the unit time of the pressure of the cleaning liquid (1 sec) ), the rate of change (pressure change rate) is set to "a", the flow rate of the cleaning liquid before switching is set to "L", and the threshold of the elapsed time from the point in time T ₀ when the drive frequency starts to be adjusted by the pump control unit 120 is set to " When set to “t”, the following equation (4) is obtained. By modifying equation (4), equation (5) can be obtained, and the threshold value t of the elapsed time can be obtained by equation (5). Additionally, the pressure change rate a is the slope of the graph according to the calculated pressure value shown in FIG. 7, and is calculated based on the number of rotations of the electric motor 118, etc. Specifically, the pressure change rate a is obtained by subtracting the pressure of the cleaning fluid at a point in time unit time (1 sec) from a certain point in time from the pressure of the cleaning fluid at a certain point in time. Additionally, the pressure of the cleaning liquid at a point in time (1 sec) from a certain point corresponds to P ₁ on the left side of the above-mentioned equation (3). Therefore, on the right side of equation (3), the flow rate L ₀ of the cleaning liquid at a certain point in time, the rotation speed r of the electric motor 118 at a time unit time (1 sec) from a certain point in time, and the intrinsic coefficient C of the pump 112 By substituting each value, the pressure of the cleaning liquid at a unit time (1 sec) from a certain point in time can be obtained.

[Formula 4]

[Formula 5]

By substituting the numerical values corresponding to each of “m”, “n”, “a”, and “P” included in the above equation (5), the calculation unit 23 can calculate the threshold t of the elapsed time. Conditions shown in Figure 7 (the number n of valves opened before switching is "4", the number m of valves opened after switching is "2", the pressure change rate a is "-3.3 MPa/sec", and the set pressure P is " The threshold t of the elapsed time calculated using equation (5) based on "10 MPa") was 2.2 sec. Therefore, the threshold t of the elapsed time calculated using Equation (5) is 1.8, which is the shortest elapsed time among the plurality of elapsed times that could avoid overshoot of the pressure of the cleaning liquid in the simulation results shown in FIG. 6. It became a slightly longer value than sec. The threshold t of the elapsed time can be said to be a general condition that can avoid overshoot of the pressure of the cleaning liquid regardless of the usage conditions of the cleaning device 110.

The calculation unit 23 calculates the rotation speed value of the electric motor 118 before the drive frequency is adjusted by the pump control unit 120, that is, the initial value r1 of the rotation speed, to the threshold t of the elapsed time, The rotation speed threshold r2 can be calculated by subtracting the value multiplied by the rate of change (rate of rotation change) b. That is, the threshold value r2 of the rotation speed is calculated based on the following equation (6). The threshold r2 of the rotation speed calculated using equation (6) based on the conditions shown in Figure 7 (the initial value r1 of the rotation speed is "11 rps" and the rotation speed change rate b is "-1.96 rps/sec") is 6.688. It was rps (401.28rpm). Additionally, since the rotational speed “1rpm” corresponds to the driving frequency “10Hz”, it is also possible to calculate the driving frequency threshold if the rotational speed threshold r2 is calculated based on the following equation (6).

[Formula 6]

Subsequently, the rotation speed change rate b, which is the rotation speed change rate of the electric motor 118, was verified. The results are shown in Figure 8. FIG. 8 is a graph showing changes over time in the rotation speed of the electric motor 118. The horizontal axis in FIG. 8 represents time (unit: “sec”), and 1 division corresponds to 1 sec. The horizontal axis of FIG. 8 indicates the point in time T ₀ at which switching of the driving frequency begins. The vertical axis in FIG. 8 represents the number of rotations (unit: “rps”). In Figure 8, four rotation speeds (original rotation speeds) of the electric motor 118 before the driving frequency is adjusted by the pump control unit 120 are displayed.

According to FIG. 8, it can be seen that the higher the rotational speed value before the point in time T ₀ when the driving frequency starts to be adjusted, that is, the higher the initial value r1 of the rotational speed, the larger the rotational speed change rate b tends to be. Specifically, when the initial value r1 of the rotation speed is around 10 rps (600 rpm), the rotation speed change rate b is -1.96 rps/sec (-117.6 rpm/sec). When the initial value r1 of the rotation speed is around 5 to 6.67 rps (300 to 400 rpm), the rotation speed change rate b is -1.77 rps/sec (-106.2 rpm/sec). When the initial value r1 of the rotation speed is around 3.33 to 5 rps (200 to 300 rpm), the rotation speed change rate b is -1.66 rps/sec (-99.6 rpm/sec). When the initial value r1 of the rotation speed is 3.33 rps (200 rpm) or less, the rotation speed change rate b is -1.41 rps/sec (-84.6 rpm/sec).

Based on the above examination, a plurality of different rotation speed change rates b depending on the initial value r1 of the rotation speed are stored in the memory unit 22 according to the present embodiment in a form linked to the initial value r1 of the rotation speed. Then, the calculation unit 23 extracts a specific rotation speed change rate b from the plurality of rotation speed change rates b stored in the memory unit 22 based on the initial value r1 of the rotation speed, and based on the extracted rotation speed change rate b. Calculate the rotation speed threshold r2. Specifically, when the calculation unit 23 acquires the initial value r1 of the rotation speed measured by the tachometer or the rotation speed automatically calculated by the valve control unit 121, it refers to the memory unit 22 and performs a plurality of rotations. From the speed change rate b, the rotation speed change rate b connected to the initial value r1 of the acquired rotation speed is extracted. The calculation unit 23 can calculate the rotation speed threshold r2 by substituting the extracted rotation speed change rate b into the above-mentioned equation (6). By calculating the rotation speed threshold r2 in this way, the accuracy related to the rotation speed threshold r2 increases. Since the valve 117 is closed by the valve control unit 121 based on this highly accurate rotational speed threshold r2, a sudden increase in pressure caused by closing the valve 117 can be appropriately suppressed.

As explained above, in the cleaning device 110 of the present embodiment, the valve control unit 121 starts to adjust the driving frequency by the pump control unit 120, and then changes the driving frequency and the rotation per unit time of the electric motor 118. When the number or elapsed time reaches the threshold, the valve 117 is closed, and the threshold is calculated based on the operating conditions related to the operation of at least one of the valve 117, the electric motor 118, and the inverter 119. It is equipped with an arithmetic unit 23 that does the following. In this way, after the driving frequency of the inverter 119 begins to be adjusted by the pump control unit 120, the driving frequency of the inverter 119, the number of rotations per unit time of the electric motor 118, or the elapsed time are, When the threshold value calculated by the calculation unit 23 is reached based on the above-described operating conditions, the valve control unit 121 closes the valve 117. The calculation unit 23 calculates a threshold value based on operating conditions related to at least one operation of the valve 117, the electric motor 118, and the inverter 119. Therefore, even if the cleaning device 110 is used in various ways, the timing at which the valve 117 is closed by the valve control unit 121 is always optimized, and a sudden increase in pressure due to the valve 117 being closed is appropriately suppressed. . This achieves high versatility.

In addition, the valve control unit 121 closes the valve 117 when the driving frequency or rotation speed reaches the threshold after the driving frequency begins to be adjusted by the pump control unit 120. In this way, compared to the case where the valve 117 is closed based on the elapsed time since the drive frequency started to be adjusted by the pump control unit 121, the operation of the inverter 119 or the electric motor 118 Since the valve 117 is closed based on this, the certainty of suppressing a sudden increase in pressure due to the closing of the valve 117 is higher.

In addition, a plurality of nozzles 11A and valves 117 are provided, and the calculation unit 23 calculates a threshold value based on the number of valves 117 closed by the valve control unit 121, and provides the value to the valve control unit 121. As the number of valves 117 closed increases, the threshold related to the driving frequency or rotation speed is decreased, and the threshold related to the elapsed time is increased. In the case where a plurality of nozzles 11A and valves 117 are provided, as the number of valves 117 closed by the valve control unit 121 increases, the pressure of the cleaning liquid due to closing of the valves 117 rapidly increases. It tends to become easier to rise. In contrast, as the number of valves 117 closed by the valve control unit 121 increases, the threshold related to the driving frequency or rotation speed is reduced and the threshold related to the elapsed time is increased. When the calculation is performed, the pressure of the cleaning liquid is sufficiently reduced until the valve 117 is closed by the valve control unit 121 based on the calculated threshold. As a result, even when the number of valves 117 that are closed by the valve control unit 121 is large, a rapid increase in pressure due to closing of the valves 117 can be more appropriately suppressed.

In addition, the calculation unit 23 calculates the first flow rate, which is the flow rate per unit time of the cleaning liquid supplied to the nozzle 11A from the pump 112 after the adjustment of the driving frequency by the pump control unit 120 is completed, and As the driving frequency is adjusted by the control unit 120, the value of the driving frequency, rotation speed, or elapsed time at the timing when the second flow rate, which is a flow rate that changes, matches the first flow rate is calculated as a threshold. The first flow rate described above can be said to be a target value of the flow rate that changes as the driving frequency is adjusted by the pump control unit 120. Here, it has been found through experience that the rate of change of the flow rate and pressure of the cleaning liquid is higher than the rate of change of the driving frequency of the inverter 119 and the rotation speed of the electric motor 118. So, the calculating unit 23 calculates the first flow rate, which is the target value, and then calculates the driving frequency at the timing when the second flow rate, which is a flow rate that changes as the driving frequency is adjusted by the pump control unit 120, matches the first flow rate. , the number of revolutions or the value of elapsed time is calculated as a threshold. If the valve control unit 121 closes the valve 117 based on the threshold value calculated in this way, the certainty of avoiding a situation in which the second flow rate becomes greater than the first flow rate at the timing when the valve 117 is closed increases. . This increases the certainty that a sudden increase in the pressure of the cleaning liquid that may occur when the valve 117 is closed is suppressed.

In addition, the calculation unit 23 calculates the value of the elapsed time at the timing when the second flow rate coincides with the first flow rate as a threshold t, and the driving frequency is adjusted by the calculated elapsed time threshold t and the pump control unit 120. The rotational speed threshold r2 is calculated based on the rotational speed change rate b, which is the rotational speed per unit time that changes as the speed changes. The threshold t of the elapsed time described above is, for example, the number of valves opened before the driving frequency is adjusted by the pump control unit 120, and the valves 117 opened before the driving frequency is adjusted by the pump control unit 120. ) is calculated by the calculation unit 23 based on the number of and the pressure change rate a, which is the pressure of the cleaning liquid per unit time that changes as the driving frequency is adjusted by the pump control unit 120. The calculation unit 23 calculates the rotation speed by subtracting the value obtained by multiplying the threshold t of the elapsed time by the rotation speed change rate b from the rotation speed of the electric motor 118 before the drive frequency is adjusted by the pump control unit 120. The threshold r2 can be calculated. Additionally, if the threshold value r2 of the rotation speed is known, it is also possible to calculate the threshold value of the driving frequency.

In addition, a memory unit that stores a plurality of different rotation speed change rates b in the form of linking them to the initial value r1 of the rotation speed according to the initial value r1 of the rotation speed before the driving frequency begins to be adjusted by the pump control unit 120. (22), and the calculation unit 23 extracts a specific rotation speed change rate b from a plurality of rotation speed change rates b stored in the memory unit 22 based on the initial value r1 of the rotation speed, and the extracted rotation speed Based on the change rate b, the rotation speed threshold r2 is calculated. The rotation speed change rate b, which is related to the rotation speed that changes as the driving frequency of the inverter 119 is adjusted, varies depending on the initial value r1 of the rotation speed before the driving frequency of the inverter 119 begins to be adjusted, As the initial value r1 of the rotation speed increases, the rotation speed change rate b also tends to increase. Therefore, when calculating the rotation speed threshold r2, the calculation unit 23 extracts the rotation speed change rate b connected to the initial value r1 of the rotation speed from a plurality of rotation speed change rates b stored in the memory unit 22. Since the calculation unit 23 calculates the rotation speed threshold r2 based on the extracted rotation speed change rate b, the accuracy related to the rotation speed threshold r2 increases. Since the valve 117 is closed by the valve control unit 121 based on this highly accurate rotational speed threshold r2, a sudden increase in pressure caused by closing the valve 117 can be appropriately suppressed.

<Other embodiments>

The technology disclosed in this specification is not limited to the embodiments described by the above description and drawings, and for example, the following embodiments are also included in the technical scope.

(1) When the valves 17, 117 that were closed before switching the driving frequency of the inverter 19, 119 are opened and the number of valves 17, 117 in the closed state decreases (valve 17 in the open state , 117) increases, the valve control unit 21, 121 outputs a signal, and the pump control unit 20, 120 increases the degree of pressurization with the cleaning liquid based on the signal. 112), it is okay to control the operation. In order to increase the degree of pressurization of the cleaning liquid, the driving frequency of the inverters 19 and 119 may be increased by the pump control unit 20 and 120.

(2) The valve control units 21 and 121 control the timing at which the valves 17 and 117 are closed and the timing at which the pump control units 20 and 120 start switching the driving frequencies of the inverters 19 and 119 (cleaning liquid). The time difference between the timing of starting to loosen the degree of pressurization) is made the same in the cases where the number of valves 17, 117 to be closed is 4 and the case is 3, and the number of valves 17, 117 to be closed is set to It is possible to make it the same in the case of 2 people and the case of 1 person, and also make it smaller than the case of 4 people and the case of 3 people.

(3) The valve control units 21 and 121 control the timing between the timing at which the valves 17 and 117 are closed and the timing at which the pump control units 20 and 120 start switching the driving frequencies of the inverters 19 and 119. It is also possible to make the time difference constant regardless of the number of valves 17 and 117 that are closed (the number of nozzles 11A from which spraying of the cleaning liquid is stopped when the valves 17 and 117 are closed).

(4) The valve control units 21 and 121 provide a time period from the timing at which the pump control units 20 and 120 start switching the driving frequencies of the inverters 19 and 119 to the timing at which the valves 17 and 117 are closed. And, the relationship between the time from the timing of closing the valves 17 and 117 to the timing of ending switching of the driving frequencies of the inverters 19 and 119 by the pump control units 20 and 120 may be made the same. It is also possible to make the former shorter than the latter.

(5) The valve control units 21 and 121 have the same timing at which the pump control units 20 and 120 start switching the driving frequencies of the inverters 19 and 119 and the timing at which the valves 17 and 117 are closed. It is also possible to do so. In addition, the valve control units 21 and 121 close the valves 17 and 117 earlier than the timing at which the pump control units 20 and 120 start switching the driving frequencies of the inverters 19 and 119. possible.

(6) In the valve control units 21 and 121, the timing at which switching of the driving frequency of the inverters 19 and 119 by the pump control units 20 and 120 ends is the same as the timing at which the valves 17 and 117 are closed. It is also possible to do so. In addition, the valve control units 21 and 121 set the timing of closing the valves 17 and 117 later than the timing at which switching of the driving frequencies of the inverters 19 and 119 by the pump control units 20 and 120 ends. It is also possible.

(7) The number of individual cleaning liquid supply passages 13B and the number of valves 17 and 117 do not have to match. For example, the valves 17 and 117 are installed at a portion where the common cleaning fluid supply path 13A and the plurality of individual cleaning fluid supply paths 13B branch, and the supply of cleaning fluid to the plurality of individual cleaning fluid supply paths 13B is controlled. It is also possible to control fertilization by opening and closing one valve (17, 117). In that case, the number of valves 17 and 117 is less than the number of individual cleaning liquid supply passages 13B.

(8) The specific arrangement and number of nozzles 11A in the nozzle head 11 can be changed as appropriate.

(9) The number of plungers 12A in the inverter/motor driven pumps 12 and 112 may be 2 or less or 4 or more.

(10) The pumps 12 and 112 may be driven by a drive system other than the inverter/motor drive system (for example, an air drive system, etc.).

(11) Specific values related to the pressure and flow rate of the cleaning liquid in the cleaning devices 10 and 110 can be changed as appropriate.

(12) The cleaning devices 10 and 110 can also be used in combination with a polishing device PD having one or three or more polishing units PO. When there is one polishing unit PO and two polishing pads PA, the number of nozzle heads 11 in the cleaning devices 10 and 110 is two. When there are three or more polishing units PO and six or more polishing pads PA, the number of nozzle heads 11 in the cleaning devices 10 and 110 is six or more.

(13) The cleaning devices 10 and 110 can also be used in combination with a polishing device (PD) in which one polishing section (PO) is equipped with one polishing pad (PA), in which case one polishing section (PO) is provided. The number of nozzle heads 11 installed corresponding to (PO) is also 1. In this case, the polishing device PD polishes one side of the semiconductor wafer using the polishing pad PA in the polishing unit PO.

(14) In addition to the above (12) and (13), the number of nozzle heads 11 installed can be changed as appropriate.

(15) The object to be cleaned by the cleaning devices 10 and 110 may be a semiconductor wafer or the like in addition to the polishing pad PA.

(16) The cleaning devices 10 and 110 may be combined with devices other than the polishing device PD, or may be used alone.

(17) It may be a liquid spray device other than the cleaning devices 10 and 110. In that case, liquid other than the cleaning liquid is sprayed from the nozzle 11A.

(18) As the valves 17 and 117, it is also possible to use a normally open type. In that case, the valve control units 21 and 121 output a closing signal when closing the valves 17 and 117 in an open state, and output a closing signal when opening the valves 17 and 117 in a closed state. By stopping, the opening and closing of the valves 17 and 117 is controlled.

(19) In addition to the explanation in Embodiment 2, the number of valves 117 provided in the cleaning device 110 can be changed to a value other than four. Likewise, the number of valves 117 that were open before closure can be changed to a number other than four. Likewise, the number of valves 117 to be closed can be changed to other than two.

(20) In addition to the explanation in Embodiment 2, in order to have the calculation unit 23 calculate the threshold, the factors fed back to the valve control unit 121 include the driving frequency of the inverter 119, the rotation speed of the electric motor 118, and Any one or two pressures of the cleaning liquid may be used.

(21) The specific value of the threshold t of the elapsed time calculated by the calculation unit 23 described in Embodiment 2 is determined by the following conditions (the number of valves to open before switching, n, the number of valves to open after switching, m, and the pressure change rate a). , depending on the set pressure P), it may be longer than 2.2sec.

(22) The specific value of the rotation speed threshold r2 calculated by the calculation unit 23 described in Embodiment 2 is other than 6.688 rps (401.28 rpm) depending on the conditions (initial value r1 of the rotation speed, rotation speed change rate b). It could be.

10, 110… Cleaning device (liquid spray device), 11A… Nozzle, 12, 112… Pump, 12A… Plunger, 17, 117… Valves, 18, 118… Electric motors, 19, 119… Inverter, 20, 120… Pump control unit, 21, 121... Valve control unit, 22… Memory unit, 23... Operation unit, b… Speed change rate, r1… Initial value, r2… Threshold of rotation speed, t… threshold of elapsed time

Claims (13)

A nozzle that sprays liquid,
a pump connected to the nozzle and pressurizing the liquid and supplying it to the nozzle;
A valve installed between the nozzle and the pump to control the distribution of the liquid by opening and closing;
A valve control unit that controls opening and closing of the valve, comprising at least a valve control unit that outputs a signal when closing the valve;
A liquid injection device comprising a pump control unit that controls the operation of the pump, and a pump control unit that controls the operation of the pump to relieve the degree of pressurization of the liquid based on the signal. The method of claim 1, comprising: an electric motor driving the pump;
Equipped with an inverter that rotates the electric motor,
The pump has at least a plunger that pressurizes the liquid according to the rotation state of the electric motor,
The pump control unit controls the rotational state of the electric motor by adjusting the driving frequency of the inverter. The liquid injection device according to claim 2, wherein the valve control unit closes the valve later than the timing at which the driving frequency of the inverter begins to be adjusted by the pump control unit based on the signal. The liquid injection device according to claim 3, wherein the valve control unit closes the valve before the timing at which the adjustment of the driving frequency of the inverter by the pump control unit ends based on the signal. The method of claim 4, wherein the time from the timing at which the driving frequency of the inverter begins to be adjusted by the pump control unit based on the signal to the timing at which the valve is closed is the timing at which the valve is closed. A liquid injection device, characterized in that the valve is closed so that it is longer than the time from when the adjustment of the driving frequency of the inverter by the pump control unit ends. The method according to any one of claims 3 to 5, wherein the nozzle and the valve are provided in plural numbers,
The valve control unit determines the time difference between the timing of closing the valve and the timing at which the driving frequency of the inverter begins to be adjusted by the pump control unit of the nozzle at which injection of the liquid is stopped according to the closing of the valve. A liquid spray device characterized in that it becomes larger as the number increases. The method according to any one of claims 3 to 6, wherein the valve control unit closes the valve at a timing before the pressure of the liquid, which decreases as the driving frequency of the inverter is adjusted based on the signal, becomes 0. A liquid injection device characterized in that. The method according to any one of claims 3 to 7, wherein the valve control unit determines the drive frequency, the number of revolutions per unit time of the electric motor, or the elapsed time since the drive frequency begins to be adjusted by the pump control unit. When the time reaches the threshold, the valve is closed,
A liquid injection device comprising a calculation unit that calculates the threshold based on operating conditions related to at least one operation of the valve, the electric motor, and the inverter. The liquid injection device according to claim 8, wherein the valve control unit closes the valve when the drive frequency or the rotation speed reaches the threshold after the drive frequency begins to be adjusted by the pump control unit. . The method of claim 8 or 9, wherein the nozzle and the valve are provided in plural numbers,
The calculating unit calculates the threshold value based on the number of the valves closed by the valve control unit, and as the number of the valves closed by the valve control unit increases, the threshold value related to the driving frequency or the rotation speed A liquid injection device characterized in that , and increasing the threshold related to the elapsed time. The method according to any one of claims 8 to 10, wherein the calculation unit is a flow rate per unit time of the liquid supplied from the pump to the nozzle after the adjustment of the driving frequency by the pump control unit is completed. The first flow rate is calculated, and the second flow rate, which is the flow rate that changes as the driving frequency is adjusted by the pump control unit, is the driving frequency, the rotation speed, or the elapsed time at a timing when the second flow rate matches the first flow rate. A liquid injection device characterized in that the value is calculated as the threshold. The method of claim 11, wherein the calculation unit calculates a value of the elapsed time at a timing when the second flow rate coincides with the first flow rate as the threshold, and the calculated threshold of the elapsed time and the pump control unit. A liquid injection device, characterized in that the threshold value of the rotation speed is calculated based on the rotation speed change rate, which is the rotation speed per unit time that changes as the driving frequency is adjusted. The method of claim 12, wherein a plurality of different rotation speed change rates are connected to the initial value of the rotation speed according to the initial value of the rotation speed before the drive frequency starts to be adjusted by the pump control unit. It is equipped with a memory unit that stores multiple memories,
The calculation unit extracts a specific rotation speed change rate from among the plurality of rotation speed change rates stored in the memory unit based on the initial value of the rotation speed, and extracts the rotation speed change rate based on the extracted rotation speed change rate. A liquid injection device characterized by calculating a threshold.