JP7444333B2 - Fluid control device and blockage detection method - Google Patents

Description

The present invention relates to a fluid control device and a method for detecting a blockage state.

A fluid control device including a piezoelectric pump and a control circuit has been developed, but Patent Document 1 describes the use of a plurality of piezoelectric pumps connected in series in order to improve performance, such as pressure. has been done. Specifically, in a fluid control device in which two piezoelectric pumps are connected in series, a first piezoelectric pump and a second piezoelectric pump are connected in series.

International Publication No. 2019/198305

However, a fluid control device that uses two piezoelectric pumps in series has a longer flow path than a fluid control device that uses one piezoelectric pump, so there is a risk of foreign matter flowing from the upstream side or coming off from the inner wall of the flow path. There is a high possibility that contamination will occur in the flow path due to foreign objects. When contamination occurs in the flow path, a blockage state occurs in the flow path, the temperature of the piezoelectric pump increases, and the possibility of failure such as cracking of the piezoelectric element of the piezoelectric pump increases.

Therefore, an object of the present disclosure is to provide a fluid control device that can easily detect the occurrence of a blockage state in a flow path, and a method for detecting a blockage state.

A fluid control device according to an embodiment of the present disclosure includes a first flow path, a first piezoelectric pump connected to one end of the first flow path, a second piezoelectric pump, and one end connected to the first piezoelectric pump, A second flow path whose other end is connected to the second piezoelectric pump, a third flow path whose one end is connected to the second piezoelectric pump, and a control capable of controlling the driving of the first piezoelectric pump and the second piezoelectric pump. and a detection unit that detects the quantity of electricity of each of the first piezoelectric pump and the second piezoelectric pump, or detects the difference between the quantities of electricity of the first piezoelectric pump and the second piezoelectric pump, and the control unit , when the first piezoelectric pump and the second piezoelectric pump are driven under predetermined driving conditions that cause fluid to flow from the other end of the first flow path to the other end of the third flow path, the amount of electricity of the first piezoelectric pump is When the detection unit detects a relationship in which the amount of electricity is less than or equal to the amount of electricity of the second piezoelectric pump, it can be determined that a blockage state has occurred in the flow path.

A method for detecting a blockage state according to an embodiment of the present disclosure includes a first flow path, a first piezoelectric pump connected to one end of the first flow path, a second piezoelectric pump, and one end connected to the first piezoelectric pump. and controlling the drive of the second flow path whose other end is connected to the second piezoelectric pump, the third flow path whose one end is connected to the second piezoelectric pump, the first piezoelectric pump, and the second piezoelectric pump. and a detection unit that detects the amount of electricity of each of the first piezoelectric pump and the second piezoelectric pump, or detects the difference in the amount of electricity of the first piezoelectric pump and the second piezoelectric pump. A detection method for detecting a blockage state of a flow path in an apparatus, wherein the first piezoelectric pump and the second piezoelectric pump are operated under predetermined driving conditions to cause fluid to flow from the other end of the first flow path to the other end of the third flow path. and detecting the amount of electricity of the first piezoelectric pump and the amount of electricity of the second piezoelectric pump, and when a relationship is detected in which the amount of electricity of the first piezoelectric pump is equal to or less than the amount of electricity of the second piezoelectric pump. , and determining that a blockage condition has occurred in the flow path.

According to the present disclosure, by detecting a relationship in which the amount of electricity of the first piezoelectric pump is equal to or less than the amount of electricity of the second piezoelectric pump, it is possible to easily detect that a blockage state has occurred in the flow path.

FIG. 1 is a schematic diagram for explaining the configuration of a nebulizer according to an embodiment. FIG. 1 is a schematic diagram showing the configuration of a pump unit according to an embodiment. FIG. 3 is a block diagram for explaining control of the pump unit according to the embodiment. FIG. 3 is a diagram showing the relationship between the operating state of the pump unit, the current of the piezoelectric pump, and the opening/closing of the valve according to the embodiment. It is a flow chart for explaining operation of a pump unit concerning an embodiment. It is a figure which shows the relationship between the operating state of the pump unit, the electric current of a piezoelectric pump, and opening/closing of a valve based on a modification.

Below, a fluid control device according to the present embodiment will be described in detail with reference to the drawings. Note that the same reference numerals in the figures indicate the same or corresponding parts.

(Embodiment)
In the following embodiment, an example will be described in which a pump unit (fluid control device) in which two piezoelectric pumps are connected in series is used in a nebulizer. A nebulizer is a device used by patients suffering from asthma or other conditions to inhale medicinal solutions orally, and uses a pump unit to create a powerful airflow to atomize the medicinal solution. The device in which the pump unit is used is not limited to a nebulizer; for example, the pump unit can be used in a discharge device such as an aroma diffuser or a humidifier, or in a suction device such as a nasal aspirator. Good too.

FIG. 1 is a schematic diagram for explaining the configuration of a nebulizer 1 according to an embodiment. The nebulizer 1 includes a pump unit 10, an air nozzle 20, an atomizing nozzle 30, a drug tank 40, and a mouthpiece 50. The patient P holds the tip of the mouthpiece 50 in his mouth and inhales the atomized drug solution discharged from the tip.

The pump unit 10 is a pump for producing compressed air, and has two piezoelectric pumps connected in series to improve performance, such as pressure. By using a piezoelectric pump, the pump unit 10 can be reduced in size and weight compared to a pump using a motor. Although not shown, the piezoelectric pump has a piezoelectric element and a pump chamber inside the housing, and the volume and pressure of the pump chamber are varied by displacement of the piezoelectric element due to driving, thereby conveying fluid. Note that the detailed configuration of the pump unit 10 will be described later.

The air nozzle 20 sends compressed air produced by the pump unit 10 toward the atomization nozzle 30. At the tip of the atomizing nozzle 30, a negative pressure is generated by the strong air flow created by the air nozzle 20, and the chemical liquid is sucked up from the chemical liquid tank 40 through the piping 42. The medicinal liquid sucked up to the tip of the atomizing nozzle 30 is atomized by the air flow from the air nozzle 20, and is delivered to the patient's P's oral cavity through the mouthpiece 50.

Next, the pump unit 10 will be described in detail with reference to the drawings. FIG. 2 is a schematic diagram showing the configuration of the pump unit 10 according to the embodiment. FIG. 3 is a block diagram for explaining control of the pump unit 10 according to the embodiment.

As shown in FIG. 2, the pump unit 10 includes a first flow path 11, a u piezoelectric pump 12 (first piezoelectric pump), a second flow path 13, and a d piezoelectric pump 14 (second piezoelectric pump). and a third flow path 15. The first flow path 11 is a flow path provided on the upstream side that takes in air. The u piezoelectric pump 12 is connected to the downstream side of the first flow path 11. The second flow path 13 is a flow path that connects the u piezoelectric pump 12 and the d piezoelectric pump 14. The d piezoelectric pump 14 is connected in series to the u piezoelectric pump 12. The third flow path 15 is a flow path connected to the d piezoelectric pump 14 and provided on the downstream side.

The pump unit 10 can improve pressure by connecting the u piezoelectric pump 12 and the d piezoelectric pump 14 in series. However, since the u piezoelectric pump 12 and the d piezoelectric pump 14 vibrate their piezoelectric elements to compress air, the u piezoelectric pump 12 and the d piezoelectric pump 14 themselves generate heat. In particular, the temperature of the d piezoelectric pump 14 on the downstream side to which air heated by the heat generated by the u piezoelectric pump 12 is sent increases further. Furthermore, in the pump unit 10, when contamination occurs in the flow path, the flow path becomes blocked and the air flow becomes stagnant, causing the temperatures of the u piezoelectric pump 12 and the d piezoelectric pump 14 to rise further. Become. When the temperature of the u piezoelectric pump 12 and the d piezoelectric pump 14 becomes high, problems such as cracks occurring in the piezoelectric elements occur.

Therefore, it is desirable for the pump unit 10 to detect whether or not a blockage state has occurred in the flow path, but if a new sensor or the like for detecting contamination is provided, manufacturing costs will increase. has a big disadvantage. In this embodiment, a configuration will be described in which it is possible to easily detect whether or not a blockage state has occurred in the flow path in the pump unit 10 without providing a new sensor or the like for detecting contamination. .

Furthermore, in this embodiment, the pump unit 10 not only detects whether or not a blockage state has occurred in the flow path, but also has a configuration that discharges contamination that has occurred in the flow path in order to eliminate the blockage state. It also has Specifically, as shown in FIG. 2, the pump unit 10 includes a first branch passage 16 connected to the first flow passage 11 and connected to the outside of the flow passage, and a u-valve 17 (a first branch passage 17 provided in the first branch passage 16). 1 valve), a second branch path 18 connected to the second flow path 13 and connected to the outside of the flow path, and a d valve 19 (second valve) provided in the second branch path 18. Note that the pump unit 10 may have a configuration that does not have a configuration for discharging contamination.

As shown in FIG. 3, the pump unit 10 includes a control circuit 100 that can control the driving of the u piezoelectric pump 12 and the d piezoelectric pump 14, and the opening and closing of the u valve 17 and the d valve 19, and the u piezoelectric pump 12. and a current sensor 200 (detection unit) that detects the current of each of the piezoelectric pumps 14. Although not shown, the nebulizer 1 has a power source that supplies the power necessary to drive the pump unit 10.

The control circuit 100 includes a CPU (Central Processing Unit) as a control center, a ROM (Read Only Memory) that stores programs and control data for the CPU to operate, and a RAM (Random Access Unit) that functions as a work area for the CPU. Memory), input/output interfaces, etc. are provided to maintain signal integrity with peripheral devices.

When the pump unit 10 is started, the u piezoelectric pump 12 and the d piezoelectric pump 14 compress the air drawn from the upstream side of the first flow path 11 (the left side in the figure), and Compressed air is sent to the air nozzle 20 from the middle right side). Therefore, the control circuit 100 drives the u piezoelectric pump 12 and the d piezoelectric pump 14 under predetermined driving conditions that cause the fluid to flow from the upstream side of the first flow path 11 to the downstream side of the third flow path 15. For example, the u piezoelectric pump 12 and the d piezoelectric pump 14 are each driven with a constant voltage. In particular, if there is no need to make the driving conditions different between the u piezoelectric pump 12 and the d piezoelectric pump 14, the u piezoelectric pump 12 and the d piezoelectric pump 14 are driven at the same constant voltage.

Even if the u piezoelectric pump 12 and the d piezoelectric pump 14 are driven at the same constant voltage, since the d piezoelectric pump 14 is located downstream of the u piezoelectric pump 12, more compressed air flows to the d piezoelectric pump 14. sent to. Therefore, in the normal state, the back pressure of the d piezoelectric pump 14 is higher than the back pressure of the u piezoelectric pump 12, so the current Id that drives the d piezoelectric pump 14 is lower than the current Iu that drives the u piezoelectric pump 12. Become. As a result, the current sensor 200 detects a relationship in which the current Iu of the u piezoelectric pump 12 is higher than the current Id of the d piezoelectric pump 14.

However, as shown in FIG. 2, when contamination 130 occurs in the second flow path 13, the flow of air within the flow path is obstructed, and a blockage state occurs within the flow path. Note that the closed state is not limited to a state in which the flow of air in the flow path is completely obstructed, but also includes a state in which the flow of air in the flow path is obstructed to a degree that is reduced compared to the normal state. When a blockage state occurs in the flow path, the back pressure in the u piezoelectric pump 12 increases, and the current Iu that drives the u piezoelectric pump 12 becomes equal to or less than the current Id that drives the d piezoelectric pump 14. Become. When the current sensor 200 detects a relationship in which the current Iu of the u piezoelectric pump 12 is equal to or less than the current Id of the d piezoelectric pump 14, the control circuit 100 can determine that a blockage state has occurred in the flow path.

In other words, the control circuit 100 controls the flow path when the u piezoelectric pump 12 and the d piezoelectric pump 14 are driven under a predetermined drive condition that causes fluid to flow from the upstream side of the first flow path 11 to the downstream side of the third flow path 15. This utilizes the fact that when a blockage state occurs in the piezoelectric pump 12, the relationship between the current Iu of the u piezoelectric pump 12 and the current Id of the d piezoelectric pump 14 is equal or reversed. Note that the driving conditions for the u piezoelectric pump 12 and the d piezoelectric pump 14 are not limited to driving at a constant voltage, but may be other driving conditions such as driving at a constant current. Further, the driving conditions of the u piezoelectric pump 12 and the driving conditions of the d piezoelectric pump 14 do not have to be the same. For example, the amount of work of the d piezoelectric pump 14 on the downstream side is greater than the amount of work of the u piezoelectric pump 12 on the upstream side. The drive conditions for the u piezoelectric pump 12 and the drive conditions for the d piezoelectric pump 14 may be made different so that the distance increases. However, when the driving conditions are different, it is necessary to drive in a range where the current Iu of the u piezoelectric pump 12 is higher than the current Id of the d piezoelectric pump 14 in the normal state.

In addition, the control circuit 100 detects the current Iu of the u piezoelectric pump 12 and the current Id of the d piezoelectric pump 14 with the current sensor 200 to determine whether a blockage state has occurred in the flow path. If the pump 12 and the d-piezoelectric pump 14 are to be driven with constant current, a voltage sensor is provided in place of the current sensor 200, and the voltage sensor detects the voltage Vu of the u-piezoelectric pump 12 and the voltage Vd of the d-piezoelectric pump 14. Then, it is determined whether a blockage condition has occurred in the flow path. Of course, the control circuit 100 may determine the electric power Wu of the piezoelectric pump 12 and the electric power Wd of the piezoelectric pump 14 to determine whether a blockage state has occurred in the flow path.

When the control circuit 100 determines that a blockage state has occurred in the flow path, it controls the d valve 19 to open in order to discharge the contamination 130 in the flow path that is the cause. FIG. 4 is a diagram showing the relationship between the operating state of the pump unit, the current of the piezoelectric pump, and the opening and closing of the valve according to the embodiment. As shown in FIG. 4, in the control circuit 100, when the operating state of the pump unit 10 is normal, the current Iu of the u piezoelectric pump 12 is higher than the current Id of the d piezoelectric pump 14, and the u valve 17 and the d valve 19 in a closed state.

The control circuit 100 is configured such that when the operating state of the pump unit 10 becomes a closed state, the current Iu of the u piezoelectric pump 12 becomes equal to or lower than the current Id of the d piezoelectric pump 14, and when the u valve 17 is closed, The valve 19 is controlled to be in an open state. At this time, the control circuit 100 continues driving the u piezoelectric pump 12 and the d piezoelectric pump 14. When the d valve 19 is opened, the second flow path 13 is opened to the atmosphere, so that the air in the second flow path 13 is discharged to the outside of the flow path through the second branch path 18. Since the contamination 130 is discharged together with the air in the second flow path 13 that is discharged outside the flow path, the blockage state that has occurred within the flow path is resolved. Note that the control circuit 100 may stop driving the u piezoelectric pump 12 and the d piezoelectric pump 14 when the operating state of the pump unit 10 becomes a closed state.

Next, the detection of a blockage state in the pump unit 10 and the operation for eliminating the blockage state will be described using a flowchart. FIG. 5 is a flowchart for explaining the operation of the pump unit 10 according to the embodiment. First, when the pump unit 10 is started, the control circuit 100 drives the u piezoelectric pump 12 and the d piezoelectric pump 14 under predetermined driving conditions (step S101).

The control circuit 100 causes the current sensor 200 to detect the current Iu of the u piezoelectric pump 12 and the current Id of the d piezoelectric pump 14 while driving the u piezoelectric pump 12 and the d piezoelectric pump 14 under predetermined driving conditions (step S102). The current Iu of the u piezoelectric pump 12 and the current Id of the d piezoelectric pump 14 detected by the current sensor 200 are input to the control circuit 100.

The control circuit 100 determines whether the detected current Iu of the u piezoelectric pump 12 is greater than or equal to the current Id of the d piezoelectric pump 14 (step S103). As shown in FIG. 4, when the detected current Iu of the u piezoelectric pump 12 is higher than the current Id of the d piezoelectric pump 14, the control circuit 100 can determine that the operating state of the pump unit 10 is the normal state. On the other hand, if the detected current Iu of the u piezoelectric pump 12 is equal to or less than the current Id of the d piezoelectric pump 14, the control circuit 100 can determine that the operating state of the pump unit 10 is a closed state.

When determining that the detected current Iu of the u piezoelectric pump 12 is higher than the current Id of the d piezoelectric pump 14 (NO in step S103), the control circuit 100 determines that the operating state of the pump unit 10 is the normal state, and executes the process. Return to S102. That is, the control circuit 100 detects the current Iu of the u piezoelectric pump 12 and the current Id of the d piezoelectric pump 14 using the current sensor 200 while continuing to drive the u piezoelectric pump 12 and the d piezoelectric pump 14 under predetermined driving conditions. continue.

On the other hand, when the detected current Iu of the u piezoelectric pump 12 is determined to be less than or equal to the current Id of the d piezoelectric pump 14 (YES in step S103), the control circuit 100 determines that the operating state of the pump unit 10 is in a closed state, and d The valve 19 is controlled to be open (step S104). That is, the control circuit 100 opens the second flow path 13 to the atmosphere and discharges the contamination 130 to the outside of the flow path. Here, the time for opening the d-valve 19 is predetermined in the control circuit 100. The control circuit 100 opens the d-valve 19 for a predetermined period of time (for example, 2 to 3 seconds) and then controls the d-valve 19 to close.

If the contamination 130 is discharged outside the flow path in the process in step S104, the blockage state in the flow path has been resolved. Therefore, after controlling the d valve 19 to close, the control circuit 100 controls the current Iu of the u piezoelectric pump 12 and the current Iu of the d piezoelectric pump 14 in order to check whether the blockage state in the flow path is resolved. The current sensor 200 is caused to detect the current Id (step S105). The current Iu of the u piezoelectric pump 12 and the current Id of the d piezoelectric pump 14 detected by the current sensor 200 are input to the control circuit 100.

The control circuit 100 determines whether the detected current Iu of the u piezoelectric pump 12 is less than or equal to the current Id of the d piezoelectric pump 14 (step S106). If the detected current Iu of the u piezoelectric pump 12 is higher than the current Id of the d piezoelectric pump 14, the control circuit 100 determines that the blockage state in the flow path has been resolved and the operating state of the pump unit 10 has returned to the normal state. be able to. On the other hand, the control circuit 100 determines that if the detected current Iu of the u piezoelectric pump 12 is less than the current Id of the d piezoelectric pump 14, the blockage state in the flow path is not resolved and the operating state of the pump unit 10 remains in the blockage state. It can be determined that there is.

When the detected current Iu of the u piezoelectric pump 12 is determined to be less than or equal to the current Id of the d piezoelectric pump 14 (YES in step S106), the control circuit 100 determines that the blockage state in the flow path has not been resolved, and performs the process. The process returns to step S104, and the d valve 19 is controlled to open again.

On the other hand, the control circuit 100 determines that the detected current Iu of the u piezoelectric pump 12 is higher than the current Id of the d piezoelectric pump 14 (NO in step S106), and the control circuit 100 determines that the blockage state in the flow path is resolved and the pump unit 10 operates. It is determined that the state has returned to normal. The control circuit 100 continues driving the u-piezoelectric pump 12 and the d-piezoelectric pump 14 under predetermined driving conditions, but determines whether an input to stop the drive of the u-piezoelectric pump 12 and d-piezoelectric pump 14 has been received from the user. A judgment is made (step S107).

If the input to stop driving the u piezoelectric pump 12 and d piezoelectric pump 14 has not been received from the user (NO in step S107), the control circuit 100 returns the process to S102. That is, the control circuit 100 detects the current Iu of the u piezoelectric pump 12 and the current Id of the d piezoelectric pump 14 using the current sensor 200 while continuing to drive the u piezoelectric pump 12 and the d piezoelectric pump 14 under predetermined driving conditions. continue.

On the other hand, when receiving an input from the user to stop driving the u piezoelectric pump 12 and d piezoelectric pump 14 (YES in step S107), the control circuit 100 stops driving the u piezoelectric pump 12 and d piezoelectric pump 14. , ends the process.

As described above, the pump unit 10 according to the embodiment includes the first flow path 11, the u piezoelectric pump 12 connected to one end of the first flow path 11, the d piezoelectric pump 14, and the u piezoelectric pump connected to one end. 12 and a second flow path 13 whose other end is connected to the d piezoelectric pump 14 , and a third flow path 15 whose one end is connected to the d piezoelectric pump 14 . The pump unit 10 further includes a control circuit 100 that can control the driving of the u piezoelectric pump 12 and the d piezoelectric pump 14, and a current sensor 200 that detects the current of each of the u piezoelectric pump 12 and the d piezoelectric pump 14. Be prepared. The control circuit 100 drives the u-piezoelectric pump 12 and the d-piezoelectric pump 14 under predetermined drive conditions that cause fluid to flow from the other end (upstream side) of the first flow path 11 to the other end (downstream side) of the third flow path 15. When the current sensor 200 detects a relationship in which the current Iu of the u piezoelectric pump 12 is equal to or less than the current Id of the d piezoelectric pump 14 during the operation, it can be determined that a blockage state has occurred in the flow path.

As a result, the pump unit 10 according to the embodiment detects the current Iu of the u piezoelectric pump 12 and the current Id of the d piezoelectric pump 14 without newly providing a sensor or the like for detecting contamination. It is possible to easily detect that a blockage state has occurred in the flow path.

The predetermined driving condition is a condition where the d piezoelectric pump 14 and the u piezoelectric pump 12 are driven with the same current, or a condition where the u piezoelectric pump 12 is driven in a range where the current Iu of the u piezoelectric pump 12 is higher than the d piezoelectric pump 14 current Id. It is preferable that there be.

The current sensor 200 may be a detection unit that detects voltage or power instead of detecting current. Note that in the present disclosure, current, voltage, or electric power is collectively referred to as an amount of electricity.

Preferably, the predetermined driving condition is a condition in which the u piezoelectric pump 12 and the d piezoelectric pump 14 are driven at a constant voltage. In particular, it is preferable that the u piezoelectric pump 12 and the d piezoelectric pump 14 be driven at a constant voltage with the same voltage.

It is preferable that the pump unit 10 further includes a first branch passage 16 connected to the first passage 11 and connected to the outside of the passage, and a U-valve 17 provided in the first branch passage 16. The control circuit 100 is capable of controlling the opening and closing of the u-valve 17, and is preferably capable of controlling the u-valve 17 to open when it is determined that a blockage condition has occurred in the first flow path 11. . Thereby, the pump unit 10 can discharge contamination in the first flow path 11 to the outside of the flow path, and can eliminate the blockage state in the first flow path 11.

It is preferable that the pump unit 10 further includes a second branch passage 18 connected to the second passage 13 and connected to the outside of the passage, and a d valve 19 provided in the second branch passage 18. The control circuit 100 is capable of controlling the opening and closing of the d-valve 19, and is preferably capable of controlling the d-valve 19 to open when it is determined that a blockage condition has occurred in the second flow path 13. . Thereby, the pump unit 10 can discharge contamination in the second flow path 13 to the outside of the flow path, and can eliminate the blocked state in the second flow path 13.

Preferably, the control circuit 100 can drive the u piezoelectric pump 12 and the d piezoelectric pump 14 when the d valve 19 is opened.

The control circuit 100 may be able to stop driving the u piezoelectric pump 12 and the d piezoelectric pump 14 when opening the d valve 19.

When the control circuit 100 detects, with the current sensor 200, a relationship in which the current Iu of the u-piezoelectric pump 12 is equal to or less than the current Id of the d-piezoelectric pump 14 after the d-valve 19 is opened for a predetermined time and the d-valve 19 is closed. It is preferable to be able to control the d valve 19 to open again. Thereby, the pump unit 10 can discharge contamination remaining in the flow path to the outside of the flow path, and eliminate the blockage state in the flow path.

This is a detection method for detecting a blockage state of a flow path in the pump unit 10, and includes a predetermined method of flowing fluid from the other end (upstream side) of the first flow path 11 to the other end (downstream side) of the third flow path 15. A step of driving the u piezoelectric pump 12 and the d piezoelectric pump 14 under drive conditions, a step of detecting the current Iu of the u piezoelectric pump 12 and the current Id of the d piezoelectric pump 14, and the step of detecting the current Iu of the u piezoelectric pump 12 when the d piezoelectric pump If a relationship in which the current Id is equal to or lower than No. 14 is detected, it is determined that a blockage state has occurred in the flow path.

As a result, the method for detecting a blockage state according to the embodiment can detect the current Iu of the u piezoelectric pump 12 and the current Id of the d piezoelectric pump 14 without newly providing a sensor or the like for detecting contamination. Therefore, it is possible to easily detect that a blockage state has occurred in the flow path.

(Other variations)
In the pump unit 10 according to the embodiment described above, when a relationship is detected in which the current Iu of the u piezoelectric pump 12 is equal to or less than the current Id of the d piezoelectric pump 14, it is determined that a blockage state has occurred in the flow path, and the d It was explained that the valve 19 is controlled to be in an open state. However, the control to open the d valve 19 is only one example of the control to eliminate the blockage state in the flow path, and other control may be used.

FIG. 6 is a diagram showing the relationship between the operating state of the pump unit, the current of the piezoelectric pump, and the opening and closing of the valve according to the modification. As shown in FIG. 6, when the operating state of the pump unit 10 is the normal state, the control circuit 100 causes the current Iu of the u piezoelectric pump 12 to be higher than the current Id of the d piezoelectric pump 14, as in FIG. Valve 17 and d-valve 19 are controlled to be closed.

When contamination occurs in the flow path and the back pressure of the u piezoelectric pump 12 is comparable to the back pressure of the d piezoelectric pump 14, the control circuit 100 controls the current Iu of the u piezoelectric pump 12 detected by the current sensor 200 to be d. Since the current is approximately the same as the current Id of the piezoelectric pump 14, it is determined that the first blocked state has occurred in the flow path.

When the back pressure of the u piezoelectric pump 12 is the same as the back pressure of the d piezoelectric pump 14 in the first closed state, the flow of air from the u piezoelectric pump 12 is not significantly obstructed, so there is no contamination in the second flow path 13. It can be inferred that a nation has arisen. Therefore, when the operating state of the pump unit 10 becomes the first closed state, the control circuit 100 controls the u-valve 17 to be closed and the d-valve 19 to be open. When the d valve 19 is opened, the second flow path 13 is opened to the atmosphere, so the air in the second flow path 13 is discharged to the outside of the flow path through the second branch path 18. Contamination within the second flow path 13 is discharged to the outside of the flow path.

When contamination occurs in the flow path and the back pressure of the u piezoelectric pump 12 becomes higher than the back pressure of the d piezoelectric pump 14, the control circuit 100 controls the current Iu of the u piezoelectric pump 12 detected by the current sensor 200 to Since the current of the pump 14 is equal to or lower than the current Id, it is determined that the second blocked state has occurred in the flow path.

When the back pressure of the u piezoelectric pump 12 is higher than the back pressure of the d piezoelectric pump 14, the flow of air from the u piezoelectric pump 12 is greatly obstructed, and the first flow path 11 is blocked by contamination. It can be inferred that Therefore, when the operating state of the pump unit 10 becomes the second closed state, the control circuit 100 controls the d-valve 19 to be closed and the u-valve 17 to be open. When the u-valve 17 is opened, the first flow path 11 is opened to the atmosphere, so the air in the first flow path 11 is discharged to the outside of the flow path through the first branch path 16. Contamination within one flow path 11 is discharged to the outside of the flow path.

In addition, in the control for eliminating the blockage state in the flow path described above, the driving or stopping of the u piezoelectric pump 12 and the driving or stopping of the d piezoelectric pump 14 may be combined.

In the pump unit 10 according to the embodiment described above, the current sensor 200 detects the current of each of the u piezoelectric pump 12 and the d piezoelectric pump 14, and the current Iu of the u piezoelectric pump 12 is equal to or less than the current Id of the d piezoelectric pump 14. It was explained that the following relationship is detected. However, the current sensor 200 does not necessarily need to detect the currents of each of the u piezoelectric pump 12 and the d piezoelectric pump 14, and detects only the difference between them so that the current Iu of the u piezoelectric pump 12 is the current of the d piezoelectric pump 14. A relationship that is less than or equal to Id may be detected. As an example of detecting only the difference with the current sensor 200, for example, the ratio of the current Id of the d piezoelectric pump 14 to the current Iu of the u piezoelectric pump 12 may be detected. Note that the reference current Iu of the u piezoelectric pump 12 is set in advance, and the current Iu of the u piezoelectric pump 12 itself is not detected. Similarly, when a voltage sensor is provided in place of the current sensor 200, it is not necessary to detect the respective voltages of the u piezoelectric pump 12 and the d piezoelectric pump 14, and only the difference between them may be detected.

The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and it is intended that equivalent meanings and all changes within the scope of the claims are included.

Reference Signs List 1 nebulizer, 10 pump unit, 11 first channel, 12, 14 piezoelectric pump, 13 second channel, 15 third channel, 16 first branch channel, 17, 19 valve, 18 second branch channel, 20 air nozzle , 30 atomization nozzle, 40 chemical tank, 42 piping, 50 mouthpiece, 100 control circuit, 200 current sensor.

Claims (11)

a first flow path;
a first piezoelectric pump connected to one end of the first flow path;
a second piezoelectric pump;
a second flow path connected to the first piezoelectric pump at one end and connected to the second piezoelectric pump at the other end;
a third flow path having one end connected to the second piezoelectric pump;
a control unit capable of controlling driving of the first piezoelectric pump and the second piezoelectric pump;
A detection unit that detects the amount of electricity of each of the first piezoelectric pump and the second piezoelectric pump, or detects the difference in the amount of electricity of the first piezoelectric pump and the second piezoelectric pump,
The control unit includes:
When the first piezoelectric pump and the second piezoelectric pump are being driven under predetermined driving conditions that cause fluid to flow from the other end of the first flow path to the other end of the third flow path, the first piezoelectric pump If the detection unit detects a relationship in which the amount of electricity of the second piezoelectric pump is equal to or less than the amount of electricity of the second piezoelectric pump, it can be determined that a blockage state has occurred in the flow path. The predetermined driving conditions are:
a condition in which the second piezoelectric pump and the first piezoelectric pump are driven with the same current or the same voltage, or
The fluid control device according to claim 1, wherein the condition is that the first piezoelectric pump is driven in a range where the amount of electricity is higher than the amount of electricity of the second piezoelectric pump. The fluid control device according to claim 1 or 2, wherein the amount of electricity detected by the detection section is a value of voltage, current, or power. The predetermined driving condition is a condition in which the first piezoelectric pump and the second piezoelectric pump are driven at a constant voltage,
The control unit includes:
If the detection unit detects a relationship in which the amount of electricity of the first piezoelectric pump is equal to or less than the amount of electricity of the second piezoelectric pump, it can be determined that a blockage state has occurred in the flow path. The fluid control device according to claim 2. The fluid control device according to claim 4, wherein the first piezoelectric pump and the second piezoelectric pump are driven at a constant voltage with the same voltage. a first branch path connected between one end and the other end of the first flow path and connected to the outside of the flow path;
further comprising a first valve provided in the first branch path,
The control unit includes:
It is possible to control opening and closing of the first valve,
The fluid control device according to any one of claims 1 to 5, wherein the first valve is controlled to be opened when it is determined that a blockage state has occurred in the first flow path. a second branch path connected between one end and the other end of the second flow path and connected to the outside of the flow path;
further comprising a second valve provided in the second branch path,
The control unit includes:
It is possible to control opening and closing of the second valve,
The fluid control device according to any one of claims 1 to 6, wherein the second valve can be controlled to be opened when it is determined that a blockage state has occurred in the second flow path. The fluid control device according to claim 7, wherein the control unit can drive the first piezoelectric pump and the second piezoelectric pump when opening the second valve. The fluid control device according to claim 7, wherein the control unit is capable of stopping driving of the first piezoelectric pump and the second piezoelectric pump when opening the second valve. After the control unit opens the second valve for a predetermined time and closes the second valve, the detection unit detects an amount of electricity of the second piezoelectric pump that is equal to or greater than an amount of electricity of the first piezoelectric pump. The fluid control device according to any one of claims 7 to 9, wherein the second valve can be controlled to be opened again if the second valve is opened. a first flow path, a first piezoelectric pump connected to one end of the first flow path, and a second piezoelectric pump, one end connected to the first piezoelectric pump and the other end connected to the second piezoelectric pump. a third flow path whose one end is connected to the second piezoelectric pump; a control unit capable of controlling driving of the first piezoelectric pump and the second piezoelectric pump; A fluid control device comprising: a detection unit that detects the amount of electricity of each of the piezoelectric pump and the second piezoelectric pump, or detects a difference in the amount of electricity of the first piezoelectric pump and the second piezoelectric pump; A detection method for detecting a blocked state of a road, the method comprising:
driving the first piezoelectric pump and the second piezoelectric pump under predetermined driving conditions that cause fluid to flow from the other end of the first flow path to the other end of the third flow path;
detecting the amount of electricity of the first piezoelectric pump and the amount of electricity of the second piezoelectric pump;
A method for detecting a blockage state, the method comprising: determining that a blockage state has occurred in a flow path when a relationship in which the quantity of electricity of the first piezoelectric pump is equal to or less than the quantity of electricity of the second piezoelectric pump is detected.

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