JP3918914B2 - Micro flow measurement device, method, computer program, and storage medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for identifying the properties of a droplet, and more particularly to an apparatus for identifying the properties of a droplet forming a micro flow rate, and an apparatus for measuring and controlling the associated micro flow rate. The present invention also relates to this method, a computer program, and a storage medium storing the same.
[0002]
[Prior art]
In the research, development, and manufacturing processes of chemicals, for example, a reagent solution has been printed and added to a strip such as a nitrocellulose membrane in a reproducible manner. An example of this is known literature, for example, Japanese Patent Publication No. 7-6975 “Apparatus and method for preparation and printing of reagent solution”.
[0003]
For printing / addition, conventionally, a means has been used in which a droplet of a reagent is ejected toward a nitrocellulose film by a nozzle device that drops liquid supplied under pressure. However, the flow rate and other properties of this reagent may change due to concentration, etc., and the flow rate may change due to accumulation of solidified material in the nozzle or other passages. It was necessary to identify and further adjust the flow rate.
[0004]
In addition, the same phenomenon occurs in an ink supply mechanism in an ink jet printer, and it is necessary to adjust a minute flow rate in a liquid flow path.
[0005]
Conventionally, detection of the current flow rate for performing these adjustments has been performed by visually confirming the ejection amount from the nozzle, detecting the weight of a certain number of droplets ejected, or the like.
[0006]
However, the addition of reagents and the use of ink in ink jet printers require high-precision flow rate control in the first place, and the concentration of liquid and accumulation in nozzles and other flow paths occur frequently or randomly. It is necessary to adjust the minute flow rate in real time, and there is a drawback that a desired effect cannot be sufficiently achieved by the conventional visual recognition and accumulation speed detection.
[0007]
[Problems to be solved by the invention]
Therefore, the main object of the present invention is to provide an apparatus for measuring and controlling the flow rate of a minute flow rate of liquid with high accuracy and in real time.
[0008]
It is another object of the present invention to provide a device that simultaneously measures and identifies the volume, viscosity, specific gravity, surface tension, and the like of ejected droplets, and further controls the flow rate and properties.
[0009]
[Means for Solving the Problems]
The present invention is a micro flow rate measuring device made in view of the above-mentioned object, which is a nozzle device having a constant diameter and ejecting a fixed number of droplets per unit time, and supplying liquid to the nozzle device And a detection device for detecting the interval between a plurality of droplets ejected by the nozzle device.
[0010]
A nozzle device having a constant aperture can eject droplets at a speed correlating with the flow rate, and on the premise that a certain number of droplets are ejected per unit time, the droplet interval is directly linked to the flow rate. Become.
[0011]
In addition, the droplet interval reflects the flow rate at that time in real time, and the first object of the present invention can be realized by detecting a physical quantity that can be detected with higher accuracy than the interval. I have to.
[0012]
The present invention also provides a liquid property measuring device, which is a nozzle device having a constant aperture and ejecting a fixed number of droplets per unit time, and a supply for supplying liquid to the nozzle device A device and a detection device for detecting an interval between a plurality of droplets ejected by the nozzle device.
[0013]
The liquid property to be measured can be any one of the volume, viscosity, specific gravity, and surface tension of the ejected droplet.
[0014]
The basic principle is the same as that of the flow rate measuring device. The volume of the ejected droplet reflects the flow rate as it is. Further, the viscosity, specific gravity, surface tension, etc. of the liquid itself correlate with the flow rate and hence the injection speed, and can be detected by the same method as the flow rate.
[0015]
The detection device advantageously has a mechanism for providing strobe illumination synchronized with droplet ejection, a camera for capturing images of a plurality of droplets synchronized and stationary by strobe illumination, and extracting feature amounts from the droplet images. And a processor for measuring a droplet interval.
[0016]
Strobe illumination synchronized with droplet ejection allows a series of droplets ejected and moved at high frequency, i.e., high frequency, to be viewed as multiple droplets that remain stationary on the video image. This facilitates detection of the droplet interval by a normal video camera, for example, an industrial or inspection video camera.
[0017]
The feature amount is advantageously obtained by extracting the centroid of the droplet from the droplet image by image processing, measuring several distances between the centroids, and averaging.
[0018]
This makes it possible to detect a drop interval more robust against disturbances and minute fluctuations.
[0019]
The nozzle device can include a strain-electric element.
[0020]
A nozzle using a strain-electric element can easily realize the function of creating a fixed number of droplets per unit time with a constant aperture, a correlation between the flow rate and the ejection speed.
[0021]
The present invention can also feedback-control the supply of the liquid forming the droplets to the nozzle device based on the measurement values of the droplet intervals obtained from these devices so that the droplet intervals are constant.
[0022]
This control can be performed by increasing or decreasing the pressure of the liquid forming the droplets to the nozzle device. For example, when the droplet interval is larger than the reference value, the pressure is decreased, and when the droplet interval is smaller than the reference value, the pressure is increased. When the allowable range of the reference value is wide, a certain hysteresis may be provided for this control.
[0023]
Moreover, it can carry out by changing the mixing | blending to the nozzle apparatus of two or more types of liquid which forms a droplet. When a certain current droplet interval is obtained, statistically obtain in advance data on what changes in the composition, for example, the extrusion pressure of each liquid type, will return the droplet interval to the initial value, and store it in the computer memory. Such a mechanism can be realized by accumulating and controlling each extrusion pressure while referring to this memory.
[0024]
These make it possible to control the flow rate of the liquid supplied in various ways, and thus control the volume, velocity, etc. of the ejected droplets.
[0025]
The present invention also provides a liquid property identification device that outputs a property value by applying a predefined correspondence between a droplet interval and a property value to a droplet interval measurement value from the liquid property measurement device.
[0026]
As a result, it is possible to display the property corresponding to the droplet interval, for example, the specific value of the volume of the droplet, in real time and with high accuracy in a unit that a human can immediately grasp.
[0027]
Such correspondence may be realized as a function by a computer program, and by storing the correspondence between the droplet interval and the volume obtained in advance in a reference table format in a memory, You may implement | achieve by picking up and displaying the droplet volume value of the record corresponding to a droplet space | interval.
[0028]
In addition to the volume of the droplet, viscosity, specific gravity, surface tension, etc. are also reflected in the droplet interval, and the viscosity of the droplet at that time can be similarly changed from the droplet interval at a certain time by using the inverse programming or corresponding measurement in advance. Reverse calculation or pickup can be performed.
[0029]
The present invention also provides a method for measuring a flow rate, the method comprising ejecting droplets from a nozzle device having a constant diameter and ejecting a certain number of droplets per unit time; Detecting an interval between a plurality of droplets ejected by the nozzle device.
[0030]
This method also makes it possible to measure the flow rate of the flow channel itself with respect to the nozzle. By obtaining a mode suitable for image processing called a droplet interval, it is possible to detect the flow rate with high accuracy.
[0031]
The present invention also provides a method for measuring liquid properties, the method comprising ejecting droplets from a nozzle device having a constant aperture and ejecting a constant number of droplets per unit time; And detecting an interval between a plurality of droplets ejected by the nozzle device.
[0032]
This liquid property can be any one of the volume, viscosity, specific gravity, and surface tension of the ejected droplet.
[0033]
This detection step advantageously includes providing a strobe illumination synchronized with droplet ejection, capturing a plurality of droplet images synchronized and stationary by the strobe illumination, and extracting feature quantities from the droplet image. And measuring a droplet interval.
[0034]
In these methods, the feature amount is advantageously obtained by extracting the centroid of the droplet from the droplet image by image processing, and measuring and averaging several distances between the centroids.
[0035]
Further, in these methods, the nozzle device can include a strain electric element.
[0036]
Further, the present invention provides a method for feedback control of supply of a liquid for forming a droplet to a nozzle device based on the droplet interval obtained by these methods so that the droplet interval is constant.
[0037]
This advantageously controls the pressure on the nozzle device of the liquid forming the droplets.
[0038]
Further, the blending of two or more kinds of liquids for forming droplets into the nozzle device may be feedback controlled so that the interval between the droplets is constant.
[0039]
The present invention also provides a liquid property identification method that outputs a property value by applying a correspondence between a predefined droplet interval and a property value to the droplet interval (measured value) obtained from the liquid property measurement method. To do.
[0040]
The present invention further includes a step of capturing an image including a plurality of ejected droplets into a storage unit in a computer system including at least a physical quantity detection unit and a storage unit, and a droplet from the image captured in the storage unit A program for executing the step of calculating the interval and the step of outputting a value related to the droplet interval is provided.
[0041]
The step of calculating the droplet interval can advantageously calculate the droplet interval by extracting the feature amount from the image captured in the storage means.
[0042]
This feature amount can be advantageously obtained by extracting the centroid of the droplet from the droplet image by image processing, and measuring and averaging several distances between the centroids.
[0043]
Such a program enables high-precision detection as described above by digital processing via a computer.
[0044]
The present invention also provides a computer-readable storage medium storing these programs.
[0045]
DETAILED DESCRIPTION OF THE INVENTION
In the embodiment of the present invention, each component is a well-known document, for example, Japanese Patent Publication No. 7-6975 “Apparatus and Method for Reagent Liquid Preparation and Printing”, Japanese Patent Laid-Open No. 9-1792 “Inkjet System”, US Patent. 4216483 “LINEAR ARRAY INK JET ASSEMBLY”, US Pat. No. 4,383,264 “DEMAND DROP FORMING DEVICE WITH INTERSTRUCTING TRANSDUCE AND DEVICIN LIFE AND DEVIC LIFE” For details of each known component that can be referred to .
[0046]
FIG. 1 shows the overall structure of an embodiment of the present invention.
[0047]
Reference numeral 1 denotes a nozzle device for ejecting the micro droplet 111. In particular, the electrostrictive element is configured by using a strain electric element, and the liquid droplets can be ejected at an initial velocity proportional to the ejection flow rate. Reference numeral 2 denotes a flow path for transporting liquid to the nozzle device, and a liquid reservoir tank (solution container) 21 forms the main part of the flow path. The flow rate can be regarded as the amount of liquid ejected from the reservoir tank through the nozzle device per unit time. Reference numeral 3 denotes a pressurizing device for generating this flow rate. Reference numeral 4 denotes a pressurization device controller for controlling the pressurization device, which has a function of measuring the current pressure related to the pressurization target and a function of controlling the pressurization amount. 5 defines the ejection frequency of the droplet, synchronizes with the imaging system, particularly a strobe 6 described later, and further physical conditions for ejecting the droplet, here the ejection timing, the amount of charge applied to the droplet, after ejection It is a controller unit that generates a synchronization signal for each control for dynamically adjusting the influence of the electric field applied to each droplet. As a droplet interval detection device, a high-frequency strobe 6 and a drop monitor camera 7 that can capture an interval between a plurality of droplets and output them as a digital still image, and a video signal from the camera connected to the camera are converted into a digital still image. A processor 8 that sequentially captures as a time series (for example, a non-compressed BMP format or a reversible / irreversible compression format such as PNG) and calculates an average droplet interval for each still image. In another embodiment, a signal line (not shown) may be provided from the controller unit 5 to the camera 7 so that the camera shutter can also be controlled synchronously. The processor 8 calculates the flow rate from the average droplet interval and displays the value on a display device 9 which is an analog RGB monitor connected to a control computer (PC) 10.
[0048]
As an example of these operation cycles, the emission and strobe can be synchronized to 47000 Hz, and the camera can capture images at about 60 Hz.
[0049]
The pressurizing device controller 4, the controller unit 5, and the processor 8 are accommodated in one PC 10, and each is connected to an external device, the pressurizing device 3, through an interface such as a GP-IB interface, or an RS-232C in another form. In addition to exchanging signals with the strobe 6, camera 7, and display device 9, device-specific data and control signals can be exchanged through an internal bus in the PC 10. Not only the flow rate measurement but also the flow rate is controlled by a program stored in advance in a memory (not shown) in the PC 10 and predefined statistical data. Originally, it is possible to identify properties such as the viscosity, specific gravity, and surface tension of the liquid droplet at that time. The PC 10 includes a communication interface for the Internet and a portable medium reading device, and can install the computer program and statistical data from various external media.
[0050]
Hereinafter, each aspect of the present embodiment will be described with reference to the accompanying drawings. The embodiments and embodiments described above and below are examples, and the scope of the present invention is limited only by the scope of the appended claims, and those skilled in the art can implement various modifications within the scope. Is possible.
[0051]
FIG. 2 is a schematic view showing a mode of ejecting microdroplets from a liquid.
[0052]
The pressurizing device 3 sends pressurized air 31 from an air supply device (not shown) to the reservoir tank 21 as the flow path 2. The amount of air fed in is adjusted by the regulator 32 in the pressurizing device 3 based on a signal from the pressure sensor in the pressurizing device 3 or by manual adjustment without using the signal in another embodiment. The
[0053]
The signal is once sent to the pressure measurement unit of the external pressurization device controller 4, and is determined by the pressurization device controller 4 or by the program, data, and / or related devices 5 and 8 in the PC 10 for further controlling this. The determination is sent as a signal to the regulator in the pressurizer. In another embodiment, the signal from the sensor can be sent to the regulator (not shown) only through the control circuit in the pressurizer.
[0054]
In particular, the reservoir tank 21 in the flow channel 2 is pressurized by the pressurizing device 3 to push out the liquid in the flow channel to the nozzle device 1.
[0055]
The nozzle device 1 is composed of an element that generates a displacement with respect to an electric signal using a strain electric element, and constantly vibrates at a constant period by a control signal from a controller unit described later, thereby constantly maintaining a constant per unit time. Inject droplet number. When the flow rate is large, the weight per droplet increases, but the initial velocity of the ejected droplet becomes faster because the size of the nozzle outlet does not change. Conversely, when the flow rate is small, the initial velocity of the droplet is slow. After ejection, the droplets stabilize at a speed that balances the air resistance and fly at a constant interval, but the interval is proportional to the initial velocity, so a wide droplet interval when the flow rate is large and a narrow droplet interval when the flow rate is small. Form.
[0056]
The collection container 22 collects the flying droplets, and the collection pump 23 returns the liquid in the collection container to the reservoir tank 2 via the check valve 24.
[0057]
The check valve 24 prevents backflow and enables accurate flow measurement.
[0058]
FIG. 3 is a block diagram showing the configuration of the controller unit 5 in order to synchronize the ejection and imaging of the droplet and adjust the physical conditions related to the ejected droplet.
[0059]
The input signal I / F 501 is a distributor for performing synchronous control for each circuit in the figure that generates control signals for the illumination (strobe) 6, the nozzle 1, and the droplet deflecting device 101. Form an internal signal interface.
[0060]
The distributor 11 may be constituted by a dedicated branch circuit or a multiplexer circuit, or may be realized through a logical channel using the internal bus of the PC 10.
[0061]
FIG. 4 is a schematic diagram showing the correspondence between the elements constituting the droplet interval detection device according to the present invention and the functions thereof. By using the nozzle control signal for controlling the nozzle device 1 and the light source control signal for controlling the LED type strobe illumination 6 to perform synchronized control, it is easy to generate a still image of the droplet.
[0062]
The camera 7 captures a droplet image with a high precision and a limited exposure time using a strobe, and transmits the image to the processor 8 in an analog video format such as NTSC.
[0063]
The processor 8 replaces the analog video format droplet image moving image, which appears to be still in synchronization with the time series of the digital still image by a known method (81), and further each digital still image. After performing digital image processing (82) such as feature extraction, the droplet interval is finally measured (83).
[0064]
The measurement result is controlled to be displayed on an appropriate display device 9 such as an RGB monitor, and further transferred as a feedback signal for controlling the pressurizing device or stored in a memory as necessary.
[0065]
For the feature extraction of still images, general methods such as binarization, clustering, and cluster centroid determination can be used.
[0066]
The droplet interval measurement 83 can be performed by, for example, averaging the intervals of a plurality of droplet centroids in the same image, and using various other known statistical methods based on the above digitization. The accuracy can be increased.
[0067]
FIG. 5 is a diagram illustrating the relationship between the nozzle device and its synchronization control mechanism.
[0068]
Here, in particular, an example is described in which the user (upper right) manually sets the synchronization condition through the user I / F in order to print the reagent on the nitrocellulose film.
[0069]
The control computer that receives a command from the input device 12 of the user I / F can send a control signal to each device, that is, the waveform generator 53, the piezoelectric driver 52, and the high-voltage power supply device 54 at an appropriate timing by an internal clock. In this example, the piezoelectric driver obtains the trigger from an external generator 524, but the control signal from the control computer can also include the trigger.
[0070]
The waveform generator 53 generates an output waveform of the charge pin 535 for giving an appropriate charge to the droplet 111 ejected from the nozzle.
[0071]
The piezoelectric driver 52 controls nozzle ejection timing. In the present invention, the injection timing is advantageously controlled to be a constant period.
[0072]
The high-voltage power source 54 controls the high-pressure plate 536 that forms a high electric field for influencing the traveling direction of the droplet after the nozzle is ejected.
[0073]
The degree of deflection of the ejected droplet 111 is determined by the degree of charge charged by the charge pin 535, and falls, for example, at a predetermined position on the nitrocellulose film. According to the present invention, for example, as a result of defining the volume of a droplet with high accuracy, the degree of deflection can be controlled with high accuracy, and eventually, an appropriate amount can be printed and added to an appropriate position with high accuracy.
[0074]
FIG. 6 is a diagram showing a correspondence between an example of imaging of a droplet ejected from a nozzle by the apparatus of the present invention and a plurality of droplet intervals that are one of the feature amounts.
[0075]
Each ellipse with a polka dot pattern represents each ejected droplet, and a thick frame represents a range of one still image corresponding to one flash of a strobe. The vertical thin line 141 in the thick frame represents the barycentric coordinate in the horizontal direction of the droplet, and the horizontal thin line 142 represents the barycentric coordinate in the vertical direction of the droplet. Each double arrow represents each droplet interval.
[0076]
In FIG. 6, d1 is the first droplet center of gravity interval, d2 is the next droplet center of gravity interval, and dn is the last droplet center of gravity interval. The average droplet spacing is d1, d2,. . . By calculating the sum of dn and dividing by n by the processor 8, it can be performed at high speed and easily.
[0077]
Such a digital image in which an auxiliary line is added to the imaging processing result can be digitally displayed on the display device 9 as it is, and may be displayed together with other information, for example, the calculation result of the average droplet interval. Good. At this time, it is possible to display the imaging processing result at each time point in real time.
[0078]
FIG. 7 is a diagram showing the correlation between the change rate of the flow rate in each flow path and the change rate of the droplet interval of each droplet ejected from each corresponding nozzle in a plurality of independent apparatuses according to the present invention.
[0079]
Specifically, using five flow rate measuring devices (corresponding to Head # 1 to Head # 5), the flow rate is changed by artificially changing the pressure of the pressurizing device, and the droplet interval measured by this device Compared with the data. Note that a certain number of droplets are collected under each condition and the weight is measured. As can be seen from FIG. 7, the flow rate change rate and the droplet interval change rate show a good correlation with high accuracy, and the following calculation formula is established. That is,
Δf ₀ : Initial flow rate (measured value at a certain reference time 0 is 100%),
Δd ₀ : Initial average droplet interval (measured value at the same reference time 0),
Δf _current : Current flow rate (estimated flow rate x% at the current time current),
Δd _current : Current average droplet interval (measured value at the current time current)
Flow rate change rate Δf (%) = Δf _current / Δf ₀ = Δd _current / Δd ₀ If the flow rate is calculated, the current flow rate Δf _current = Δf ₀ ・ (Δd _current / Δd ₀ ).
[0080]
FIG. 8 is a flowchart showing the operation of the mechanism that controls the flow rate based on the droplet interval using the conventional imaging processing, image processing, and the above calculation formula.
[0081]
First, when the program starts (S150), the distance Δd between the droplets as an initial reference value is set. ₀ Is measured (S151). This is because the current droplet interval Δd at the reference initial point _current Is obtained by the droplet interval measurement (sub) routine (S155) on the left side of the figure, and Δd _current Δd ₀ This is achieved by substituting into (S152).
[0082]
The reference initial point can be considered as the time immediately after the state of the system such as the nozzle is improved.
[0083]
In addition, the droplet interval measurement (sub) routine (S152) is displayed as a subroutine for convenience, but independent of the main flow of the program, that is, the control context by parallel processing by a multiprocessor, interrupt processing by a single processor, and the like. It can also be configured to always be executed. In this case, the measurement result Δd at that time is stored at a predetermined position in the memory using a static global variable or the like. _current Is configured to write (S158).
[0084]
As described above, the current droplet interval measurement routine (S152) performs the current droplet interval Δd. _current With this value (S158), control is returned to the main flow (if configured as a subroutine) (S159).
[0085]
Δd obtained in the main flow _current Δd ₀ (S152), this Δd ₀ Is defined as the initial droplet spacing, ie 100%.
[0086]
When the setting of the initial value is completed in this way, the process proceeds to the infinite loop (repetition) phase (S153, S154) for measuring the change with time of the droplet interval. The infinite loop phase can be interrupted or terminated at an appropriate time by inputting a command from an input device (not shown) of the computer.
[0087]
In the infinite loop phase, the distance between droplets at that time is measured at regular time intervals (S153, S155 to S159). The measurement is also performed by directly using the inter-droplet distance estimation routine by calling a subroutine or indirectly using a global variable or the like.
[0088]
Thus, Δd obtained at that time _current And already obtained Δd ₀ Based on the above, the calculation formula Δd _current / Δd ₀ The change rate of the droplet interval is obtained from × 100 (%) (S154), and this is displayed on the display device 9 or the like as the change rate of “flow rate” from the initial point.
[0089]
Such an infinite loop may also be controlled by interrupt control or by an unconditional branch instruction of a program. In the case of interrupt control, measurement and corresponding display can be automatically repeated at regular time intervals by a timer.
[0090]
Δd _current And Δd ₀ Or a ratio of the two can be used as a source of a feedback control signal to a pressurizing device or the like. Such digital values are directly or indirectly transmitted to the pressurizer controller 4 through the internal shared bus or a dedicated channel under the control of the control computer 10, and the D / A converter, etc. of the pressurizer controller 4 is transmitted. It becomes an analog value, and becomes a control signal to the regulator of the pressurizing device.
[0091]
Specifically, when the analog value reflecting the droplet interval is larger than a certain reference value, the regulator controls to reduce the pressurization amount, and when it is small, the pressurization amount is increased. Take control. This control is provided with a certain hysteresis. This is advantageously provided by a program by the control computer 10. In another embodiment, it is physically provided at the regulator level.
[0092]
The above-described series of mechanisms substantially enables a minute flow rate to be detected and controlled accurately and in real time.
[0093]
【The invention's effect】
According to the present invention, it is possible to measure the flow rate of a very small amount of liquid, particularly a droplet, with high accuracy and in real time. This makes it possible to perform particularly constant control. It is also possible to measure and identify the properties of the liquid, such as the volume, viscosity, specific gravity, and surface tension of the ejected droplets, and to control the minute flow rate based on this measurement.
[0094]
Further, according to the present invention, it is possible to detect a physical quantity that can be detected with higher accuracy than an interval with respect to detection of a flow rate.
[0095]
In addition, it is possible to detect a droplet interval more robust against disturbances and minute fluctuations.
[0096]
Furthermore, the present invention can easily realize the function of correlating the flow rate with the ejection speed and creating a certain number of droplets per unit time.
[Brief description of the drawings]
FIG. 1 is an overall view showing an embodiment of the present invention.
FIG. 2 is a schematic diagram showing a configuration for ejecting micro droplets from a liquid.
FIG. 3 is a block diagram showing a configuration of a controller for synchronizing ejection of a droplet and imaging and adjusting a physical condition related to the droplet.
FIG. 4 is a schematic diagram showing correspondence between elements constituting the droplet interval detection device according to the present invention and respective functions thereof;
FIG. 5 is a diagram illustrating a relationship between a nozzle device and a synchronization control mechanism thereof.
FIG. 6 is a diagram showing a correspondence between an example of imaging of a droplet ejected from a nozzle by the apparatus of the present invention and a plurality of droplet intervals, which is one of its feature amounts.
FIG. 7 is a diagram showing a correlation between a flow rate change rate in each flow path and a drop interval change rate of droplets ejected from each corresponding nozzle in a plurality of independent apparatuses according to the present invention.
FIG. 8 is a flowchart showing the operation of a mechanism for controlling the flow rate based on the droplet interval.
[Explanation of symbols]
1 nozzle
2 Channels (most)
3 Pressurizer
4 Pressurizer controller
5 Nozzle-strobe synchronization controller unit
6 Strobe
7 Camera
8 Droplet spacing processor
9 Display device
10 Control computer
11 Distributor
21 Reagent or ink reservoir tank
22 Collection container
23 Collection pump
24 Check valve
31 Pressurized air
32 Regulator
101 Droplet deflecting device
111 droplets

Claims (14)

  A nozzle device (1) having a constant diameter and ejecting a fixed number of droplets per unit time, a supply device for supplying liquid to the nozzle device (1), and a nozzle device (1) And a detection device (6, 7, 8) for detecting an interval between a plurality of droplets. The detection device (6, 7, 8) provides a mechanism (5, 6) for providing strobe illumination synchronized with droplet ejection, and a camera (7) for capturing images of a plurality of droplets synchronized and stationary by the strobe illumination. The apparatus according to claim 1 , further comprising: a processor (8) that extracts a feature amount from the droplet image and measures a droplet interval. 3. The apparatus according to claim 2 , wherein the feature amount is obtained by extracting a centroid of a droplet from a droplet image by image processing, and measuring and averaging several distances between the centroids. 4. A device according to any one of the preceding claims , characterized in that the nozzle device (1) comprises a strained electrical element. The apparatus according to any one of claims 1 to 4 , wherein the supply device is feedback-controlled so that the droplet interval is constant based on the measured value of the droplet interval. The apparatus according to any one of claims 1 to 4 , wherein the supply pressure to the nozzle of the supply device is feedback-controlled so that the droplet interval is constant based on the measured value of the droplet interval. Based on the measurements of the droplet spacing so that the droplets interval is constant, claim feedback control of the blending of the nozzle device of the two or more liquids for forming a droplet in the supply device (1) The apparatus according to any one of 1 to 4 .   A method of measuring a flow rate, a step of ejecting droplets from a nozzle device having a constant diameter and ejecting a predetermined number of droplets per unit time, and ejected by the nozzle device (1) And a step of detecting an interval between the plurality of droplets. The detection step includes a step of providing strobe illumination synchronized with droplet ejection, a step of capturing images of a plurality of droplets synchronized and stationary by the strobe illumination, and extracting a feature amount from the droplet image to detect a droplet interval. The method of claim 8 , further comprising the step of: The method according to claim 9 , wherein the feature amount is obtained by extracting a centroid of a droplet from a droplet image by image processing, and measuring and averaging several distances between the centroids. 11. A method according to any one of claims 8 to 10 , characterized in that the nozzle device (1) comprises a strained electrical element. 12. The method according to claim 8 , further comprising a step of feedback-controlling the supply of the liquid forming the droplets to the nozzle device (1) based on the obtained droplet intervals so that the droplet intervals are constant. The method according to one item. 12. The method according to claim 8 , further comprising a step of feedback-controlling the pressure of the liquid forming the droplets to the nozzle device (1) based on the obtained droplet interval so that the droplet interval is constant. The method according to claim 1. Based on the droplet spacing obtained, the incorporation into form droplets of two or more of the nozzle device of the liquid (1), further comprising the step of feedback control such that the droplet spacing is constant, claim 8 To 11. The method according to any one of 11 to 11 .

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