JP2007152165A - Gas pulse ejection apparatus and microdroplet generation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas pulse ejection apparatus capable of ejecting gas pulses precisely controlled in peak pressure and pulse width. <P>SOLUTION: The gas pulse ejection apparatus 10 has a gas supply source 11, an ejection port 12, and a peak pressure generation section 13 connected to the gas supply source 11 and the ejection port 12, wherein the peak pressure generation section 13 includes a first pressure adjusting means 13a and a first stop valve 13b connected to the ejection port 12 of the first pressure adjusting means 13a, and releases the gas on the first pressure adjusting means 13a side to the ejection port 12 when the first pressure adjusting means 13a is opened. The first pressure adjusting means 13a is equipped with a first pressure reducing mechanism and a first pressure opening mechanism which is connected to the ejection port 12 side of the first pressure reducing mechanism and releases the gas on the ejection port 12 side of the first pressure reducing mechanism to the atmosphere when the pressure on the ejection port 12 side of the first pressure reducing mechanism exceeds the pressure P<SB>1</SB>. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a gas pulse ejection device that ejects gas pulses. The present invention also relates to a micro droplet generator that generates micro droplets.

With the recent development of science and technology, high-definition printing materials and various devices have progressed, and techniques for handling minute droplets are increasing. As such techniques, for example, a printer that prints a high-definition photograph comparable to a silver salt photograph, an electronic circuit manufacturing process that does not apply etching, a three-dimensional resin modeling system, and the like are known and put into practical use.
In the technology for handling such fine droplets as described above, further improvement in performance is required.

In order to improve the performance of the technology for handling microdroplets, it is necessary to investigate the behavior of the microdroplets, and for that purpose it is required to generate microdroplets.
As a method for generating micro droplets, a so-called inkjet method is known in which micro droplets are ejected by pressure generated by deformation of a piezo element or bubbles generated by heating a liquid flow path. In this ink jet method, micro droplets can be continuously discharged.
In addition, an apparatus has been devised that discharges a certain amount of liquid by applying air pressure to the liquid filled in a syringe or the like for a short time (see, for example, Patent Documents 1 and 2). In the apparatuses described in Patent Documents 1 and 2, a pressure change in a syringe filled with a liquid is detected, and an on-off valve is feedback-controlled based on the pressure change to generate micro droplets. According to this method, it is possible to discharge a certain amount of liquid without depending on the viscosity or remaining amount of the liquid.
JP-A-63-97259 Japanese Patent Publication No. 8-32315

  However, in the ink jet method, the amount of liquid ejected is very small, but the mechanism (head) of the ejection unit tends to be large, so the field of view from the vertical direction and the horizontal direction is limited, and micro droplets There was a problem that it was not possible to observe where the lands on the adherend. Further, in the inkjet method, since the importance of high-speed ejection in the mechanism of the ejection unit is emphasized, the ejection energy is set higher. As a result, small droplets called satellites are often generated before and after the main droplet in a single discharge, and if it is intended to observe a single droplet exactly, it is inkjet. The law was not suitable.

  On the other hand, in the apparatuses described in Patent Documents 1 and 2, since the discharge portion can be made thin, the discharged liquid can be easily observed. However, the devices described in Patent Documents 1 and 2 have been developed for the purpose of discharging a few microliters of liquid (hereinafter, “microliter” is expressed as “μL”). When the application time is shortened and the liquid discharge amount is extremely small, for example, 50 nanoliters (hereinafter “nanoliter” is expressed as “nL”) or less, stable discharge is realized. could not.

In order to generate minute droplets, it is necessary to make the gas energy applied to the liquid substantially equal to the energy required for droplet generation. For this purpose, the peak pressure and peak pressure of the gas pulse continue. It is necessary to precisely control the energy of the gas pulse by precisely controlling the pulse width. However, in Patent Documents 1 and 2, it is considered that gas pulses whose peak pressure and pulse width are precisely controlled cannot be discharged.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a gas pulse ejection device capable of ejecting a gas pulse whose peak pressure and pulse width are precisely controlled. It is another object of the present invention to provide a micro droplet generator that can stably form a single micro droplet.

The present invention includes the following configurations.
(1) A gas pulse discharge device having a gas supply source for supplying a gas having a pressure P ₀ , a discharge port, and a peak pressure generation unit connected to the gas supply source and the discharge port,
The peak pressure generating unit includes a first pressure adjusting unit and a first on-off valve connected to the discharge port side of the first pressure adjusting unit, and the first pressure on-off valve is opened when the first on-off valve is opened. The gas on the pressure adjusting means side is discharged to the discharge port,
The first pressure adjusting means is connected to the first pressure reducing mechanism for reducing the pressure P ₀ of the gas supplied from the gas supply source to the pressure P ₁ , and the discharge port side of the first pressure reducing mechanism. gas pulse discharge the pressure, characterized in that it comprises a first pressure relief mechanism for releasing the gas in the discharge port side of the first pressure reducing mechanism to the atmosphere when it exceeds the pressure P ₁ at the discharge port side of the pressure reducing mechanism apparatus.
(2) In parallel with the peak pressure generating unit, further includes a base pressure generating unit connected to the gas supply source and the discharge port,
The base pressure generating unit includes a second pressure adjusting unit, and the second pressure adjusting unit reduces the pressure P ₀ of the gas supplied from the gas supply source to a pressure P ₂ (P ₂ <P ₁ ). a second pressure reducing mechanism connected to the discharge port side of the second pressure reducing mechanism, the pressure at the discharge port side of the second pressure reducing mechanism of the discharge port side of the second pressure reducing mechanism when exceeds the pressure P ₂ The gas pulse ejection device according to (1), further comprising a second pressure release mechanism that releases the gas to the atmosphere.
(3) The gas pulse discharge according to (1) or (2), further including an exhaust unit that is connected to the discharge port side of the peak pressure generation unit and includes a second on-off valve whose outlet side communicates with the atmosphere or a reduced-pressure atmosphere. apparatus.
(4) A microdroplet generating device that generates a microdroplet by applying a gas pulse to a liquid,
The gas pulse ejection device according to any one of (1) to (3) and a liquid-filling thin tube connected to the ejection port of the gas pulse ejection device and having a diameter on the tip side of 0.5 to 100 μm are provided. Micro droplet generator.

The gas pulse discharge device of the present invention can discharge a gas pulse whose peak pressure and pulse width are precisely controlled.
The micro droplet generator of the present invention can stably form a single micro droplet.

(Gas pulse discharge device)
An embodiment of the gas pulse ejection device of the present invention will be described.
FIG. 1 shows a gas pulse ejection device of this embodiment. The gas pulse ejection device 10 includes a gas supply source 11, an ejection port 12, a peak pressure generation unit 13 and a base pressure generation unit 14 connected to the gas supply source 11 and the ejection port 12. The gas supply source 11 to the peak pressure generation unit 13 are connected by a first pipe 15a, and the peak pressure generation unit 13 to the discharge port 12 are connected by a second pipe 15b. The base pressure generating unit 14 is connected to the gas supply source 11 by a third pipe 15c branched from the first pipe 15a, and connected to the discharge port 12 by a fourth pipe 15d that joins the second pipe 15b. Has been. Thereby, the peak pressure generator 13 and the base pressure generator 14 are connected to the gas supply source 11 and the discharge port 12 in parallel.
Moreover, the exhaust part 16 is connected to the downstream of the location where the 4th piping 15d of the 2nd piping 15b joins.
Furthermore, a mist separator 17 and a filter 18 for purifying gas are installed in order from the gas supply source 11 side on the upstream side of the portion where the third pipe 15c of the first pipe 15a is branched. .

The gas supply source 11 supplies a gas having a pressure P ₀ higher than atmospheric pressure, and examples thereof include a compressor and a cylinder.
The discharge port 12 communicates the second pipe 15 b and the outside of the gas pulse discharge device 10. Although it does not restrict | limit especially as the discharge port 12, It is preferable that it can connect with other piping.

The peak pressure generating unit 13 includes a first pressure adjusting valve 13a as a first pressure adjusting unit, a first on-off valve 13b provided on the discharge port 12 side of the first pressure adjusting valve 13a, comprising a first pressure gauge 13c which is connected to a fifth piping 15e between the pressure regulating valve 13a and the first on-off valve 13b of, and generates a peak pressure P ₁ of the gas pulse.
The first pressure regulating valve 13a includes a first pressure reducing mechanism that reduces the pressure P _{0 of} the gas supplied from the gas supply source 11 to P ₁ (P ₁ <P ₀ ), and a discharge port side of the first pressure reducing mechanism. And a first pressure release mechanism connected to the inside of one housing. Here, the first pressure release mechanism is configured so that the pressure on the discharge port 12 side of the first pressure reduction mechanism is increased when the pressure on the discharge port 12 side of the first pressure reduction mechanism exceeds the pressure P ₁ (P ₁ > atmospheric pressure). It releases gas to the atmosphere.
An example of such a first pressure regulating valve 13a is a nozzle flapper type pressure regulating valve as described in JP-A-10-198433. The nozzle flapper type pressure regulating valve has the same function as a known pressure reducing valve, and also has a pressure releasing function by the nozzle flapper.

The adjustment pressure sensitivity of the first pressure adjustment valve 13a is preferably 0.0001 to 0.01 MPa. The peak pressure _{P 1} of the gas pulse is often on the order of 0.01 MPa, adjusting the pressure sensitivity of the first pressure regulating valve is greater than 0.01 MPa (insensitive) and variation of the peak pressure _{P 1} of the gas pulse The width tends to increase. If the adjustment pressure sensitivity of the first pressure adjustment valve 13a is less than 0.0001 MPa, the working pressure / sensitivity ratio becomes too large, and the production tends to be difficult.
Here, the adjusted pressure sensitivity is the minimum value of the difference between the predetermined pressure at which the pressure reducing mechanism operates and the actual pressure on the discharge port side, and is a value that serves as an index of pressure control accuracy.

The pressure rating (full scale pressure) of the first pressure regulating valve 13a is not less than the pressure P _{0 of the} gas to be supplied and is 0.01 to ₁ MPa higher than the peak pressure P ₁ of the desired gas pulse. Is preferred. When the pressure rating of the first pressure regulating valve 13a is less than 0.01MPa respect to the peak pressure P ₁ of the desired gas pulse, the generation of gas pulses becomes difficult, and when it exceeds 1 MPa, the regulated pressure sensitivity It becomes difficult to meet.

The first on-off valve 13b included in the peak pressure generation unit 13 is an electromagnetic valve that opens and closes in response to an electrical signal. Among the first on-off valves 13b, since the pulse width of the gas pulse can be shortened, an electromagnetic valve having a response time of 15 milliseconds or less is preferable, and an electromagnetic valve having a response time of 10 milliseconds or less is more preferable. However, in order to realize a response time of less than 1 millisecond, the valve body must be driven at a very high speed, which causes a problem in the durability of the valve. Therefore, the response time of the first on-off valve 13b is: It is preferable that it is 1 millisecond or more.
Here, the response time is the time from when an electric signal is received until the valve is fully opened or fully closed. The response time required for full opening and the response time required for full closing are not necessarily the same.
Examples of the type of solenoid valve that satisfies the response time include a direct-acting small solenoid valve.As the valve body structure, for example, a spool valve, a poppet valve, etc. can be adopted, but there is little leakage, A poppet valve is preferred because of its fast response.

The first on-off valve 13b is preferably a two-way valve, but there is no problem even if a three-way valve or the like is blind-plugged to replace the two-way valve.
Although the first on-off valve 13b can generate a gas pulse even when it is normally closed (NC) or normally opened (NO), it is preferably closed from the viewpoint of power consumption.
The rated pressure of the first on-off valve 13b, it is preferable for the gas pulses to be generated is the peak pressure P ₁ or more.
The material of the portion of the first on-off valve 13b that is in contact with the gas is not particularly limited, and a material used for a normal electromagnetic valve can be used.

  The maximum flow rate (size) of the first on-off valve 13b is not particularly limited, but if it is too small, the pressure rise of the gas pulse tends not to be sudden due to the pressure loss of the solenoid valve, and if it is too large, the response of the solenoid valve. There is a tendency that the time is increased and the pressure rise is not rapid. Therefore, it is preferable to select a flow rate suitable for generating a gas pulse.

  It is preferable to install a surge killer or the like on the first on-off valve 13b in order to prevent a failure due to electrical noise generated when the first on-off valve 13b is opened / closed.

The opening / closing of the first on-off valve 13b in the present embodiment is controlled by the drive control device 19. The drive control device 19 is not particularly limited as long as the rated voltage and current of the first on-off valve 13b can be controlled, and is a known drive circuit including a device for controlling the opening time, the drive timing, and the like of the first on-off valve 13b. Can be applied. For example, an electronic relay, a transistor, a solid state relay (SSR), an electronic element such as a triac, or a mechanical device such as a relay can be applied.
It is preferable that a line filter is inserted in the drive control device 19 in order to prevent malfunction due to noise and outflow of noise to the power supply side.

  Devices that control the opening time, drive timing, etc. include, for example, various electronic timers, timer relays, programmable logic controllers (PLCs: commonly called sequencers), pulse generators, oscillators, function generators, semiconductor circuits using timer ICs, personal Examples include computer input / output terminals. However, in order to control the first on-off valve 13b at an accurate timing, a device having an accuracy of 10 milliseconds is preferable, and a device having an accuracy of 1 millisecond is preferable, and an accuracy of sub-millisecond is provided. An apparatus is preferred.

The first on-off valve 13b may be directly driven by a device that controls the opening time, drive timing, or the like, or may be indirectly driven via a transistor, a relay, or the like.
The first on-off valve 13b may be electrically connected to the device that controls the opening time, drive timing, and the like, or may be electrically insulated by a relay or the like.

If the driving voltage of the first on-off valve 13b is too low, it is difficult to obtain a driving torque necessary for high-speed response, and if it is too high, noise is generated during driving or a load is imposed on the control circuit. It is preferable that
The drive current may be direct current or alternating current, but direct current is preferable because it can be controlled by a normal transistor circuit. The smaller rated drive power of the solenoid valve is preferable in terms of power consumption as long as the required response time is satisfied.

  As the first pressure gauge 13c provided in the peak pressure generator 13, a pressure range corresponding to the working pressure of the gas pulse discharge device 10 may be used, but the response speed and the internal volume are small. An electronic pressure gauge is preferred.

The base pressure generating unit 14 includes a second pressure adjusting valve 14a that is a second pressure adjusting unit, a backflow prevention valve 14b provided on the discharge port 12 side of the second pressure adjusting valve 14a, and a second pressure. and and a second pressure gauge 14c which is connected to the sixth pipe 15f between the control valve 14a and the check valve 14b, and generates a base pressure P ₂ of the gas pulses.
The second pressure regulating valve 14a includes a first second pressure reducing mechanism that reduces the pressure P _{0 of} the gas supplied from the gas supply source 11 to P ₂ (atmospheric pressure <P ₂ <P ₁ <P ₀ ), A second pressure release mechanism connected to the discharge port side of the second decompression mechanism is provided in one housing. Here, the second pressure relief mechanism, which the gas discharge port 12 side of the second pressure reducing mechanism when the pressure at the discharge port 12 side of the second pressure reducing mechanism exceeds the pressure P ₂ is released into the atmosphere It is.
As the second pressure regulating valve 14a, the same one as the first pressure regulating valve 13a can be used.

  The pipes 15a to 15f used in the gas pulse discharge device 10 are not particularly limited, and the same pipes as those of ordinary pneumatic equipment can be used. Specifically, metal pipes such as stainless steel pipes and copper pipes, plastic tubes, and the like can be used. Especially, since it is simple, the method of connecting the flexible piping made from nylon or polyurethane with a quick connector (joint) is preferable.

Although it does not specifically limit as the internal diameter of piping 15a-15f, if too thick, the volume in a piping will become large and it will become difficult to propagate a pressure change, and if too thin, pressure loss will become large and a loss will arise in propagation of pressure. For these reasons, the inner diameters of the pipes 15a to 15f are preferably 0.5 to 6 mm.
As the wall thickness of the pipe 15a~15f it may be any thickness to withstand the peak pressure P ₁ of the gas pulses, but can not be bent into a desired shape too thick, too thin vibration during gas pulse generator May occur.

Exhaust unit 16 is to pressure in the second pipe 15b by lowering the pressure P ₁ in the second pipe 15b more quickly is further prevented from accumulating. The exhaust part 16 of the present embodiment includes a second on-off valve 16a whose outlet side communicates with the atmosphere or a reduced pressure atmosphere. The outlet side of the second on-off valve 16a normally communicates with the atmosphere, but preferably communicates with a reduced-pressure atmosphere when exhausting at high speed.
As the drive control device 19 for driving the second on-off valve 16a provided in the exhaust part 16, the same one as the peak pressure generating part 13 can be used. However, the second open / close valve 16a provided in the exhaust unit 16 may have a response time required for full opening of 15 milliseconds or less, and the response time required for full closure is not particularly limited.
In the exhaust part 16, a silencer (silencer) or the like may be installed at the outlet of the exhaust part 16 in order to reduce the exhaust sound during exhaust.

  The kind of gas applied to the gas pulse ejection device 10 is not particularly limited, and examples thereof include air, nitrogen, argon, helium and the like. Moreover, although corrosive gas, combustible gas, and auxiliary combustion gas can also be used, in that case, the material and equipment of each flow path of the gas pulse discharge apparatus 10 are selected according to the kind of those gases. It is preferable.

  An example of a gas pulse ejection method using the gas pulse ejection device 10 will be described. In addition, this example is an example which discharges a gas pulse with a fixed period. In addition, as the first on-off valve 13b and the second on-off valve 16a in this example, a normally closed valve that opens only when an electrical signal is received is used.

In the gas pulse discharge method, first, set the time to continue the peak pressure P ₁ in the drive control device 19 (the sum of the peak pressure P ₁ and the duration of the base pressure P ₂₎ (peak width) and pulse period. Based on the setting, first, the first on-off valve 13b of the peak pressure generating unit 13 is closed without sending an electrical signal to the first on-off valve 13b and the second on-off valve 16a, and the exhaust unit 16 The second on-off valve 16a is closed. Accordingly, the gas pressure P ₀ from the gas supply source 11 supplies a base pressure generating unit 14, the pressure of the gas at the second pressure regulating valve 14a of the base pressure generating unit 14 is decreased to P ₂ base pressure P ₂ is generated, and a gas having a base pressure P ₂ is supplied to the discharge port 12. This predetermined time (duration of the base pressure P ₂₎ is continued.
Thereafter, by sending a pulse electric signal to the first on-off valve 13b from the drive control unit 19, it opens the first on-off valve 13b for a predetermined time (duration of the peak pressure P _1). Accordingly, the gas pressure was adjusted to the peak pressure P ₁ by the first pressure regulating valve 13a, to release the discharge opening 12 side of the first on-off valve 13b. Then, the gas in the peak pressure P ₁ propagates toward the discharge port 12 via the second pipe 15b, and discharges from the discharge port 12. In this way, it causes sudden pressure change, generating a gas pulse of the peak pressure P _1.
Next, at the same time as the first on-off valve 13b is closed, a pulse electric signal is sent from the drive control device 19 to the second on-off valve 16a to open the second on-off valve 16a for a predetermined time, and the second The gas in the pipe 15b is released into the atmosphere to quickly reduce the pressure. Thereafter, the first on-off valve 13b and the second on-off valve 16a are closed again, and gas is supplied to the discharge port 12 via the base pressure generation unit 14. By repeating this operation, gas pulses are repeatedly discharged at a constant period.

In the gas pulse discharge method, the pressure P ₀ of the gas supplied from the gas supply source 11 is within a range of 0.01 to ₁ MPa with respect to the peak pressure P ₁ of the generated gas pulse in order to realize stable pressure control. High is preferred. When the pressure P _{0 of the} gas supplied from the gas supply source 11 is less than 0.01 MPa, a sufficient back pressure for operating the first pressure regulating valve 13a may not be obtained. The pressure fluctuation when the first pressure regulating valve 13a is activated increases, and the pressure from the first pressure regulating valve 13a to the discharge port 12 tends to become unstable.

  The pulse width of the gas pulse generated by the gas pulse discharge device 10 is preferably 1 to 100 milliseconds. The pulse width of the gas pulse can be appropriately determined depending on the opening time and the response time of the first on-off valve 13b of the peak pressure generating unit 13.

  The opening time of the second on-off valve 16a is preferably about 1 to 200 milliseconds in order to sufficiently reduce the pressure in the second pipe 15b. If the opening time of the second on-off valve 16a is less than 1 millisecond, the pressure in the second pipe 15b cannot be lowered sufficiently, and if it exceeds 200 milliseconds, the gas flows backward from the discharge port 12. In addition, gas consumption tends to increase.

  In the above example, the second on-off valve 16a of the exhaust unit 16 is opened at the same time as the first on-off valve 13b of the peak pressure generating unit 13 is closed. May need to be lowered before the first on-off valve 13b begins to close. On the other hand, when it is desired to moderate the pressure drop of the gas pulse, the opening timing of the second on-off valve 16a may be delayed.

In the gas pulse discharge device 10 described above, because the first pressure regulating valve 13a of peak pressure generator 13 comprises a first pressure relief mechanism, the discharge port 12 side than the first pressure reducing mechanism a predetermined pressure P ₁ When it exceeds, the gas on the discharge port 12 side can be discharged to the atmosphere from the first pressure reducing mechanism, and the pressure in the second pipe 15b can be quickly reduced. As a result, it is possible to discharge a gas pulse in which the pressure in the second pipe 15b is stabilized and the peak pressure and the pulse width are precisely controlled.
Further, since the gas pulse discharge device 10 has a base pressure generation unit 14, it is possible to keep applying a base pressure P ₂ before applying the peak pressure P _1, when caused the gas pulse The amount of pressure change can be reduced. Furthermore, since the base pressure generation unit 14 includes the backflow prevention valve 14b, the gas pulse generated in the peak pressure generation unit 13 is suppressed from flowing into the second pressure regulating valve 14a of the base pressure generation unit 14, It is possible to prevent malfunction of the second pressure regulating valve 14a.

  The gas pulse ejection device 10 can be applied not only to a device that generates minute droplets, which will be described later, but also suitable for applications such as cooling a minute part, blowing minute foreign matter, or turning over a semiconductor chip.

In addition, the gas pulse discharge apparatus of this invention is not limited to embodiment mentioned above.
For example, in the above-described embodiment, the first pressure adjusting means and the second pressure adjusting means are both provided with the pressure reducing mechanism and the pressure releasing mechanism in the housing. However, like the pressure reducing valve and the safety valve, A valve that opens when the predetermined pressure is reached may be provided separately.
In the embodiment described above, the base pressure generation unit 14 includes the backflow prevention valve 14b. However, instead of the backflow prevention valve 14b, the base pressure generation unit 14 includes a two-way solenoid valve or a three-way solenoid valve, and generates a base pressure when a peak pressure is applied. The second pressure regulating valve 14 a of the unit 14 may be disconnected from the peak pressure generating unit 13.
Further, the gas pulse ejection device 10 may not include the base pressure generation unit 14 and / or the exhaust unit 16.
In the above-described embodiment, the gas pulses are ejected at a constant cycle, but may be ejected at a non-constant cycle. Alternatively, a single gas pulse may be discharged without repeatedly discharging the gas pulse.

(Micro droplet generator)
One embodiment of the microdroplet device of the present invention will be described.
FIG. 2 shows the microdroplet device of this embodiment. The microdroplet device 1 according to the present embodiment includes the gas pulse ejection device 10 described above, and a liquid filling capillary 20 connected to the ejection port 12 (see FIG. 1) of the gas pulse ejection device 10 via a connection tube 21. (Hereinafter abbreviated as a narrow tube 20).

The thin tube 20 is a tube filled with the liquid 22 and having a diameter of 0.5 to 100 μm on the tip 23 side. Here, the tip of the thin tube 20 is an end on the side from which the liquid 22 is discharged. If the diameter of the capillary tube 20 on the distal end 23 side exceeds 100 μm, fine droplets of 50 nL or less cannot be generated, and the liquid 22 is ejected even when no peak pressure is applied. If the diameter of the narrow tube 20 on the tip 23 side is less than 0.5 μm, the peak pressure P ₁ of the gas pulse must be increased in order to discharge the liquid 22. When discharging the liquid 22 in the high gas pulse peak pressure P ₁ is generation of the droplets becomes unstable, not only is not stable liquid volume is ejected as liquid 22 scatters, single liquid Drops cannot be formed.
The diameter of the narrow tube 20 on the tip 23 side is preferably 1/5 to 1/2 of the diameter of the droplet to be generated, although it varies depending on the viscosity and surface tension of the liquid 22 to be used. If the diameter on the tip 23 side of the thin tube 20 is less than 1/5 of the diameter of the droplet to be generated, the droplet may drop before reaching the desired droplet diameter, exceeding 1/2. In this case, a desired droplet diameter may not be obtained.
Although the length of the thin tube 20 is not specifically limited, 1-10 cm is preferable from the ease of handling.

  The material of the thin tube 20 is preferably a material suitable for the liquid 22 to be filled, but is preferably metal from the standpoint of robustness and ease of handling. From the viewpoint of the visibility of the liquid 22, glass is preferable. Further, it may be a plastic such as polytetrafluoroethylene, polyethylene, acrylic resin, polystyrene, or a ceramic such as alumina or zirconia.

The shape of the thin tube 20 is not particularly limited as long as the diameter on the tip 23 side is in the above range, but if the entire thin tube 20 has an inner diameter of 100 μm or less, the flow path resistance becomes too large, and a high pressure is applied to the discharge of microdroplets. Therefore, it is preferable that the tip 23 of the thin tube 20 is tapered. Further, the thin tube 20 may be a straight tube as shown in the drawing, or may be a bent tube bent in the middle.
The outer diameter of the thin tube 20 other than the tapered portion is not particularly limited, but is preferably 0.3 to 5 mm, and the inner diameter is preferably 5 to 90% of the outer diameter.

The opening surface on the tip 23 side of the capillary tube 20 is preferably perpendicular to the central axis of the capillary tube 20 on the tip 23 side, because droplets are easily generated. When the opening surface on the distal end 23 side of the narrow tube 20 is not perpendicular to the central axis of the narrow tube 20 on the distal end 23 side, it tends to be difficult to generate droplets.
Further, if there are fine scratches or irregularities in the opening on the distal end 23 side of the thin tube 20, there is a possibility that droplet generation may be hindered. Further, it may be processed smoothly by heat treatment or chemical treatment, or may be subjected to corrosion resistance treatment, wear resistance treatment, water repellency treatment, oil repellency treatment, etc. according to the liquid 22 to be filled. Furthermore, an antistatic treatment or a conductive treatment may be applied to give a charge to the droplet.

The connecting pipe 21 is preferably as short as possible. When the connecting pipe 21 becomes long, not only does it take time to transmit the gas pulse, but it tends to be insensitive to pressure rise and fall.
The inner diameter of the connecting tube 21 is preferably 0.2 to 5 mm. If the inner diameter of the connecting pipe 21 is less than 0.2 mm, the pressure loss tends to increase. If the inner diameter exceeds 5 mm, not only does it take time to transmit the gas pulse, but the pressure rises and falls. It is in.
As a material of the connection pipe 21, for example, metal, plastics, rubbers, and the like can be used.

  The thin tube 20 and the connection tube 21 may be connected using a ferrule, an O-ring, packing, or the like, or may be directly fixed and connected by adhesion, welding, soldering, or the like. When the connecting tube 21 is a flexible tube such as silicone rubber, the thin tube 20 can be connected by being inserted into the tube.

An example of a method for generating microdroplets using the microdroplet generating apparatus will be described.
First, the liquid 22 is filled into the thin tube 20. The method of filling the liquid 22 into the thin tube 20 is not particularly limited. For example, a method of connecting the thin tube 20 to a syringe and press-fitting the liquid, a three-way valve is provided in the middle of the pipe to the thin tube 20, and the three For example, a method of filling the liquid 22 by press-fitting from one of the valves may be used. When a three-way valve is provided in the middle of piping to the thin tube 20, the liquid 22 can be press-fitted while the thin tube 20 is connected to the gas pulse discharge device 10.

Next, the narrow tube 20 is connected to the gas pulse ejection device 10 via the connection tube 21, and an object (such as a sheet) that receives the droplet is disposed on the extension of the tip 23 of the narrow tube 20. Then, a gas pulse is ejected from the gas pulse ejection device 10, the gas pulse is supplied to the narrow tube 20 through the connection tube 21, the liquid 22 filled in the narrow tube 20 is pushed out, and the tip 23 side of the narrow tube 20 Discharge more. Here, since the pulse width of the gas pulse is short, the amount of liquid droplets to be ejected is very small (for example, 50 nL or less).
Then, the droplet generated at the tip of the thin tube 20 is brought into contact with an object that receives the droplet, or separated from the thin tube 20 by static electricity, compressed air, vibration, or the like, and transferred to the surface of the object that receives the droplet. Or

In the minute droplet generating apparatus 1, for producing a desired droplet, the peak pressure P ₁ and the pulse width of the gas pulses supplied to the capillary 20, the different shapes of the capillary tube 20, the flow path loss, such as by ambient temperature Therefore, it is difficult to decide uniquely. Further, since the energy required for droplet generation is small and the amount of energy required is easily influenced by the flow path resistance and the viscosity and temperature of the liquid 22, it is difficult to obtain theoretically, and therefore, the energy is supplied to the narrow tube 20. peak pressure P ₁ and the pulse width of the gas pulses is preferably determined empirically.
As an example of the peak pressure _{P 1} and the pulse width of the gas pulses, using a "JIS viscosity standard solution 2.5 cps (manufactured by Nippon Grease Co.)", from the capillary tube 20 having an opening size of 5 [mu] m, when to produce droplets of 10pL the peak pressure _{P 1} of the gas pulse is 0.03 MPa, the pulse width is about 30 milliseconds.

In the microdroplet generation apparatus 1 described above, since the gas pulse ejection apparatus 10 is used, a gas pulse in which the peak pressure P ₁ and the pulse width of the gas pulse are precisely controlled can be sent to the capillary tube 20. As a result, a gas having substantially the same energy as that required for droplet generation can be sent to the capillary tube 20, and minute droplets can be generated stably.
Moreover, in this micro droplet production | generation apparatus 1, since a droplet can be discharged from the thin tube 20, a droplet can be observed by arbitrary methods, such as a microscope. In addition, if bent tubules are used, droplets can be observed from both vertical and horizontal directions.
Further, the fine droplet generating device 1 described above, since the gas pulse discharge device 10 has a base pressure generation unit 14, the base pressure when the liquid 22 in the capillary tube 20 not to apply the peak pressure P ₁ it can be applied to P _2. Therefore, even if the pressure of the gas pulse applied to the fine droplet is small, the fine droplet can be generated. In addition, since the pressure fluctuation during the generation of the gas pulse can be reduced, it is possible to discharge the droplets stably.

Examples of the present invention are shown below.
Example 1
The microdroplet generating apparatus of the present embodiment is shown in FIG. 2, in which a thin tube 20 is connected to a gas pulse ejection device 10 shown in FIG.
The first pressure regulating valve 13a of the peak pressure generating unit 13 of the gas pulse discharge device 10 is a nozzle flapper type pressure regulating valve having a pressure sensitivity of 0.001 MPa and having a pressure reducing mechanism and a pressure releasing mechanism. The first on-off valve 13b is an electromagnetic valve (NC-type direct acting miniature poppet valve, rated 24V) having an open / close response time of 10 milliseconds.
The second pressure regulating valve 14a of the base pressure generating unit 14 has a pressure sensitivity of 0.001 MPa, and is a nozzle flapper type pressure regulating valve including a pressure reducing mechanism and a pressure releasing mechanism.
The pipes 15a to 15f are hard polyurethane tubes having an inner diameter of 2 mm and an outer diameter of 4 mm, and are connected to each valve and member using a quick connector.
The second on-off valve 16a of the exhaust unit 16 is an electromagnetic valve (NC type direct acting miniature poppet valve, rated 24V) with an open / close response time of 10 milliseconds each.
The first on-off valve 13b and the second on-off valve 16a are driven by DC 24V through an electronic relay by a program timing device. A multi-function generator 8116A manufactured by Hewlett-Packard Company was used as the program timing device.

The capillary tube 20 is made of glass having an outer diameter of 1 mm, an inner diameter of 0.5 mm, and a length of 4 cm, in which a capillary tube having an outer diameter of 7 μm, an inner diameter of 5 μm, and a length of 1 mm is formed by tapering the tip 23 side. The tip 23 of the thin tube was fixed downward in the vertical direction. The tip of the thin tube 20 can be observed with a microscope from the horizontal direction.
The connecting tube 21 is a polypropylene tube having an outer diameter of 1 mm, an inner diameter of 0.5 mm, and a length of 40 cm.
The thin tube 20 and the connecting tube 21 were connected using a polypropylene joint.

First, “JIS viscosity standard solution 2.5 cps (manufactured by Nippon Grease Co., Ltd.)” was pressed into the narrow tube 20 from a syringe. Further, the pressure of the gas supplied from the gas supply source 11 is reduced from 0.3 MPa to 0.050 MPa by the first pressure regulating valve 13a of the gas pulse discharge device 10, and the 0.050 MPa gas is reduced to the first pressure. This was supplied to the on-off valve 13b.
At the same time, the pressure of the gas supplied from the gas supply source 11 is reduced from 0.3 MPa to 0.020 MPa by the second pressure regulating valve 14 a, and the gas having the base pressure of 0.020 MPa is directed toward the discharge port 12. Circulated. This was continued for 500 milliseconds.
Thereafter, a pulse electric signal of DC 24V was sent to the first on-off valve 13b (see FIG. 3A), and the first on-off valve 13b was opened for 30 milliseconds. By opening the first on-off valve 13b, and is propagated to the capillary tube 20 through a connecting pipe 21 a gas peak pressure P ₁ from the discharge port 12. Next, at the same time as the first on-off valve 13b is closed, a 24 V DC electric pulse signal is sent to the second on-off valve 16a of the exhaust section 16 (see FIG. 3B), and the second on-off valve 16a. And the pressure in the second pipe 15b was quickly lowered. As a result of the operation and measurement of the change in pressure at the discharge port of the gas pulse discharge device, the pressure difference between the base pressure P ₂ and the peak pressure P ₁ is 0.03 MPa, as shown in FIG. It was confirmed that a gas pulse with a width of 30 milliseconds was generated with high accuracy.
A 10 pL droplet was generated from the opening on the tip 23 side of the thin tube 20 by the gas pulse. When the generated droplet was blown off with compressed air, a droplet of 10 pL was generated again after 500 milliseconds and had reproducibility.

(Comparative Example 1)
As the first on-off valve 13b and the second on-off valve 16a, instead of a nozzle flapper type pressure adjusting valve having a pressure adjusting sensitivity of 0.001 MPa, a diaphragm type pressure adjusting valve having a pressure adjusting sensitivity of 0.02 MPa without a pressure release mechanism is used. A gas pulse ejection device and a microdroplet production device were produced in the same manner as in Example 1 except that they were used. And the gas pulse was discharged like Example 1. FIG. When the pressure change at the outlet of the gas pulse discharge device in this example was measured, pressure fluctuation (hunting) occurred immediately after the peak pressure generation and immediately after the opening of the second on-off valve, and pressure fluctuation also occurred when the base pressure was generated. (See FIG. 4).
Further, in the same manner as in Example 1, it was applied to a gas pulse to the capillary filled with liquid, resulting droplets even when not applied peak pressure P _1, yet the amount of liquid droplets generated during peak pressure is applied Was not constant.

Since the gas pressure discharge device of the present invention can precisely control the peak pressure and the pulse width and can stably discharge a gas pulse having an extremely short pulse width of 00 milliseconds or less, it can be used in the precision industrial field. Widely applicable.
In addition, the microdroplet generation apparatus of the present invention is a characteristic analysis of various liquids, an analysis of liquid absorption behavior of various materials, a contact angle measurement of a minute part, precision printing, electronic circuit fabrication, a microchemical reaction, a microbiochemical reaction, It can be used for enzyme reaction, etching, micro-molding and the like.

It is a figure which shows typically one Embodiment of the gas pulse discharge apparatus of this invention. It is a figure which shows typically one Embodiment of the micro droplet production | generation apparatus of this invention. (A) is a timing chart diagram of a signal for driving the first on-off valve in the first embodiment, (b) is a timing chart diagram of a signal for driving the second on-off valve in the first embodiment, (C) is a pressure change figure in the discharge outlet of the gas pulse discharge device in Example 1. FIG. It is a pressure change figure in the discharge outlet of the gas pulse discharge device in Example 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Minute droplet production | generation apparatus 10 Gas pulse discharge apparatus 11 Gas supply source 12 Discharge port 13 Peak pressure generation part 13a 1st pressure adjustment valve 13b 1st on-off valve 13c Pressure gauge 14 Base pressure generation part 14a 2nd pressure adjustment Valve 14b Backflow prevention valve 14c Pressure gauge 15a 1st piping 15b 2nd piping 15c 3rd piping 15d 4th piping 15e 5th piping 15f 6th piping 16 Exhaust part 16a 2nd on-off valve 17 Mist separator 18 Filter 19 Drive control device 20 Narrow tube 21 Connecting tube 22 Liquid 23 Tip

Claims (4)

A gas pulse discharge device comprising a gas source for supplying gas pressure P _0, and the discharge port, and a peak pressure generator connected to the gas source and the discharge port,
The peak pressure generating unit includes a first pressure adjusting unit and a first on-off valve connected to the discharge port side of the first pressure adjusting unit, and the first pressure on-off valve is opened when the first on-off valve is opened. The gas on the pressure adjusting means side is discharged to the discharge port,
The first pressure adjusting means is connected to the first pressure reducing mechanism for reducing the pressure P ₀ of the gas supplied from the gas supply source to the pressure P ₁ , and the discharge port side of the first pressure reducing mechanism. gas pulse discharge the pressure, characterized in that it comprises a first pressure relief mechanism for releasing the gas in the discharge port side of the first pressure reducing mechanism to the atmosphere when it exceeds the pressure P ₁ at the discharge port side of the pressure reducing mechanism apparatus. In parallel with the peak pressure generating unit, further comprising a base pressure generating unit connected to the gas supply source and the discharge port,
The base pressure generating unit includes a second pressure adjusting unit, and the second pressure adjusting unit reduces the pressure P ₀ of the gas supplied from the gas supply source to a pressure P ₂ (P ₂ <P ₁ ). a second pressure reducing mechanism connected to the discharge port side of the second pressure reducing mechanism, the pressure at the discharge port side of the second pressure reducing mechanism of the discharge port side of the second pressure reducing mechanism when exceeds the pressure P ₂ The gas pulse discharge device according to claim 1, further comprising a second pressure release mechanism that releases the gas to the atmosphere.   3. The gas pulse discharge device according to claim 1, further comprising an exhaust unit that is connected to the discharge port side of the peak pressure generation unit and includes a second on-off valve having an outlet side communicating with the atmosphere or a reduced pressure atmosphere. A microdroplet generation device that generates a microdroplet by applying a gas pulse to a liquid,
A microfluid comprising the gas pulse ejection device according to any one of claims 1 to 3 and a liquid-filling capillary tube connected to the ejection port of the gas pulse ejection device and having a tip-side diameter of 0.5 to 100 µm. Drop generator.

Images