JP2009136519A - Fluid injection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid injection apparatus for injecting droplets in a pulse form at a high speed. <P>SOLUTION: The fluid injection apparatus 100 is for reducing the volume of a fluid chamber provided inside a volume variable chamber by diaphragms 40 and 41 and injecting fluid in the pulse form, and is provided with a tube 80 for supplying liquid to the fluid chambers 62-64 and a fluid injection part 10 disposed at the distal end of the tube 80. In the fluid injection part 10, the plurality of volume variable chambers 21-23 are serially disposed through communicating paths 33 and 35 between an entrance flow path 37 communicated to one end of the tube 80 and an exist flow path 31 communicated to a fluid injection opening 30 for injecting the liquid. The cross sectional area of the exit flow path 31, the communicating paths 33 and 35 and the entrance flow path 37 respectively is smaller than the cross sectional area perpendicular to the liquid flowing direction of the respective fluid chambers 62, 63 and 64. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fluid ejecting apparatus including a plurality of variable volume chambers.

  Surgery with the ejected fluid allows the incision of the organ parenchyma while preserving the vasculature such as blood vessels, and the incidental damage to living tissue other than the incision is minimal, resulting in a burden on the patient. In addition, since the bleeding is small and bleeding does not interfere with the field of view of the operative field, rapid surgery is possible.

  As a surgical device using such a fluid to be ejected, a liquid supply control device arranged separately from a liquid ejecting portion (nozzle) is provided with a pump as a liquid pressurizing source, and the liquid is ejected by a flexible tube. There is known an endoscopic surgical apparatus that guides to a section and injects it as a high-pressure continuous flow (see, for example, Patent Document 1).

  Further, the liquid is supplied from the opening of the nozzle provided at the distal end of the rigid connecting flow channel pipe in which the connecting flow channel is drilled from the outlet flow channel communicating with the fluid chamber by changing the volume of the fluid chamber. Has been proposed (see, for example, Patent Document 2).

JP 63-99853 A (2nd page, FIG. 1) Japanese Patent Laying-Open No. 2005-152127 (pages 8 to 10 and FIG. 1)

  In Patent Document 1 described above, a liquid supply control device having a pump as a fluid pressurizing source is disposed via a tube at a position far from a nozzle for ejecting liquid. Therefore, while the liquid is flowing through the tube, the pressure of the liquid decreases due to the fluid resistance in the tube, and when the tube is bent, the pressure of the flowing liquid fluctuates and the fluid speed is stable. It is predicted that injection cannot be performed.

  Further, in Patent Document 2 filed by the present inventor, control parameters such as the peak value of pulsation, the frequency of pulsation, the number of pulsations constituting the fluid group, the interval between the fluid group and the fluid group can be set. By appropriately setting these, it is possible to appropriately excise the soft tissue of a living body whose hardness and structure change from place to place. However, since the connection flow channel pipe (connection flow channel) has rigidity and is as long as 100 to 200 mm, the liquid ejection speed becomes slow while flowing through the connection flow channel tube, and the liquid in the connection flow channel tube It is conceivable that the droplets ejected due to the influence of the reflection of the pressure wave, etc. are combined and the pulsed ejection cannot be performed.

  Furthermore, since the connecting channel tube has rigidity and a laminated type is adopted as the piezoelectric element, it is not possible to provide a fluid ejecting portion at the tip of a thin tube that is inserted into a blood vessel like a catheter. It is considered difficult.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A fluid ejecting apparatus according to this application example is a fluid ejecting apparatus that ejects fluid in a pulse form from a fluid ejecting opening by reducing the volume of a fluid chamber provided in a variable volume chamber with a diaphragm. A tube for supplying fluid to the fluid chamber, and a fluid ejecting unit disposed at a tip of the tube, and the fluid ejecting unit includes an inlet channel and a fluid communicating with one end of the tube. A plurality of the variable volume chambers are arranged in series via the communication passage between the outlet flow passage communicating with the fluid ejection opening for ejecting the fluid, and in the cross-sectional area perpendicular to the fluid flow direction, A cross-sectional area of each of the communication path, the outlet channel, and the inlet channel is smaller than that of the fluid chamber.

  According to such a configuration, the variable volume on the inlet flow path side (hereinafter sometimes referred to as the rear stage side) with respect to the variable volume chamber on the fluid ejection opening side side (hereinafter sometimes referred to as the front end side or the front stage side). The chamber feeds a fluid whose pressure has been increased into the variable volume chamber on the front end side, and becomes a fluid resistance component against the back flow of the fluid when the volume of the fluid chamber of the variable volume chamber on the front end side is reduced.

  In particular, when a thin shape is required for the instrument itself, as in brain surgery, the amount of fluid chamber in each variable volume chamber is reduced, so that sufficient fluid cannot be supplied into the variable volume chamber on the tip side. Is predicted. Therefore, by providing the rear-stage variable volume chamber and supplying the fluid to the distal-end volume variable chamber, it is possible to supply sufficient fluid into the distal-end volume-variable chamber.

  In addition, when the volume of the fluid chamber is reduced inside the fluid chamber on the distal end side, a proper flow may not be ejected in a pulsed manner due to a back flow that occurs in the inlet channel. Therefore, there is an effect that the volume of the fluid chamber of the subsequent volume variable chamber can be reduced to generate a fluid resistance component, and pulsed droplet ejection can be performed.

  Application Example 2 In the fluid ejecting apparatus according to the application example described above, the plurality of variable volume chambers include the fluid chamber provided in each of the variable volume chambers, the communication passage communicating the fluid chambers with each other, and the fluid ejection A thin plate-like spacer that forms the outlet channel that communicates the opening and one of the fluid chambers, a side wall of each of the inlet channels, and a diaphragm that is in close contact with both the front and back surfaces of the spacer; And a piezoelectric element provided on the outer surface of the fluid chamber of the diaphragm.

  According to such a configuration, the fluid chamber, the outlet channel, the inlet channel, and the communication channel are configured such that a plurality of variable volume chambers are provided in order to configure the upper and lower lids with diaphragms and the side walls with spacers. However, the number of components can be reduced, and the fluid ejecting unit can be downsized.

  Application Example 3 In the fluid ejecting apparatus according to the application example described above, it is preferable that the inlet channel, the fluid chamber, the communication channel, and the outlet channel are arranged on a substantially straight line.

  When a flow path that bends between the outlet flow path, the fluid chamber, the communication path, and the inlet flow path is configured, fluid resistance is generated in the bent portion. However, by arranging each on a straight line, the fluid resistance in the flow path can be suppressed and fluid can be smoothly supplied to the fluid chamber on the tip side.

  Further, by arranging the outlet channel, the fluid chamber, the communication channel, and the inlet channel in a straight line, a cylindrical fluid ejecting unit can be configured even in a structure including a plurality of variable volume chambers. In addition, there is an effect that a fluid ejecting portion can be provided at the tip of a thin tube such as a catheter.

  Application Example 4 In the fluid ejection device according to the application example described above, it is preferable that a cross-sectional shape perpendicular to the fluid flow direction of the inlet channel, the communication channel, and the outlet channel is a quadrangle.

  The outlet channel, the plurality of fluid chambers, the communication channel, and the side walls of the inlet channel are formed by thin plate spacers. A thin plate-like spacer can be easily formed integrally with the spacer main body, for example, by press punching, etching, or the like, and the cross-sectional shape of each of the above-described flow paths is a quadrangle. At this time, the cross-sectional area of each flow path is the same as the height of the spacer, and the thickness of the spacer is constant. There is an effect that it can be easily done.

  Application Example 5 In the fluid ejecting apparatus according to the application example described above, it is preferable that the corner portion of the inner side wall of the fluid chamber is smoothly rounded.

  In a device that ejects fluid by reducing the volume of a fluid chamber with a diaphragm and increasing the internal pressure, it is considered that the pressure in the fluid chamber cannot be sufficiently increased when minute bubbles are present in the fluid chamber. And bubbles tend to stay in the corners of the fluid chamber. Therefore, by smoothly rounding the corners of the inner side wall of the fluid chamber, it is possible to prevent the bubbles from staying and to easily discharge the bubbles from the fluid ejection opening during the fluid ejection.

  Application Example 6 In the fluid ejecting apparatus according to the application example described above, it is preferable that the width of the side of the communication passage where the fluid flows into the fluid chamber is larger than the width of the side where the fluid flows out of the fluid chamber.

  In the flow direction of the fluid, the fluid flows easily by the diffusion effect by reducing the cross-sectional area of the communication path on the outflow side than the inflow side of the fluid. In the reverse direction of the fluid flow, the fluid flows by the nozzle effect. Make it harder to do. Accordingly, with the above-described configuration, the flow from the fluid chamber on the rear stage to the fluid chamber on the front stage is promoted, and the flow (that is, the backflow) from the fluid chamber on the front stage to the fluid chamber on the rear stage is suppressed. be able to.

  Application Example 7 In the fluid ejecting apparatus according to the application example described above, it is preferable that the fluid ejecting section has a cylindrical shape, and the diameter of the fluid ejecting section and the diameter of the tube are substantially equal.

  According to such a configuration, by making the diameter of the fluid ejecting portion and the tube substantially the same, it is possible to pass through the inside of the capillary having the same diameter as the tube (for example, inside the vascular structure such as a blood vessel). It is easy to pull out and does not damage the inner wall of the thin tube.

  Application Example 8 In the fluid ejecting apparatus according to the application example described above, it is preferable that a distal end portion of the fluid ejecting portion in the direction of the fluid ejecting opening is rounded into a substantially hemispherical shape.

  According to such a configuration, by rounding the tip of the fluid ejecting unit, for example, the tube is a catheter, and it is possible to prevent the fluid ejecting unit from being easily inserted into a thin tube such as a blood vessel, thereby preventing the blood vessel from being damaged. . In addition, by providing a fluid ejection opening at the tip, it is easy to visually recognize the microsurgical part.

  Application Example 9 In the fluid ejecting apparatus according to the application example described above, at least one of the plurality of variable volume chambers excluding the variable volume chamber communicating with the fluid ejecting opening is a reservoir for retaining fluid. preferable.

  When the fluid chamber on the front end side is pressurized and then the pressure is released, the fluid may flow slightly, and this fluid may collide with the next ejected droplet and may not form a proper droplet. Therefore, the flow of the fluid after the pressure is released can be suppressed by arranging the latter variable volume chamber as a reservoir. At this time, if the volume of the fluid chamber of the subsequent variable volume chamber is restored, it is more effective.

  Application Example 10 In the fluid ejection device according to the application example described above, it is preferable that at least an inner wall of a fluid chamber communicating with the fluid ejection opening among the plurality of variable volume chambers is subjected to a hydrophilic treatment.

  When hydrophilic treatment is applied to the inner wall of the fluid chamber, bubbles are less likely to stay on the inner wall surface, and when pressurized, the bubbles are discharged from the fluid ejection opening together with the fluid. There is an effect that can be.

  Application Example 11 In the fluid ejecting apparatus according to the application example described above, it is preferable that the volume change timings of the fluid chambers of the plurality of variable volume chambers are matched.

  According to such a configuration, the pressure of the fluid chamber in the rear stage is increased at the timing of reducing the volume of the fluid chamber in the volume variable chamber on the front end side (exit flow path side), so that the fluid in the rear stage is changed from the fluid chamber on the front end side. The backflow of the fluid to the chamber can be suppressed, and droplets of an appropriate size can be ejected in pulses from the fluid ejection opening.

  Application Example 12 In the fluid ejecting apparatus according to the application example described above, the volume of the fluid chamber in the volume variable chamber on the inlet flow channel side with respect to the volume variable chamber on the outlet flow channel side among the plurality of variable volume chambers. It is desirable to precede the change timing.

  According to such a configuration, the time at which the pressure waves generated in the respective variable volume chambers reach the fluid ejection openings can be made simultaneously, and strong and sharp droplet ejection can be realized from the fluid ejection openings. .

  Application Example 13 In the fluid ejecting apparatus according to the application example described above, of the plurality of variable volume chambers, the fluid chamber of the variable volume chamber on the inlet flow channel side of the variable volume chamber on the fluid ejection opening side is selected. It is desirable to delay the volume change timing.

  According to such a configuration, since pressure waves successively reach the fluid ejection openings, a relatively slow droplet ejection lasts for a long time, which is effective for excising soft tissue.

  Application Example 14 In the fluid ejection device according to the application example described above, it is preferable that the preceding time or delay time of the volume change timing is within a half cycle of the drive signal.

  According to such a configuration, the volume change timing of the fluid chamber of the volume variable chamber on the front end side and the fluid chamber of the subsequent volume variable chamber is set to be within a half cycle of the drive signal, so that the volume change timing described above is obtained. Thus, it is possible to realize a fluid ejecting apparatus having an effect obtained by shifting the position.

Hereinafter, embodiments will be described with reference to the drawings.
1 to 5 show a fluid ejecting apparatus according to a first embodiment, FIG. 6 shows a second embodiment, and FIG. 7 shows a third embodiment.
Note that the drawings referred to in the following description are schematic views in which the vertical and horizontal scales of members or portions are different from actual ones for convenience of illustration.
In addition, the fluid ejecting apparatus according to the present invention can be used in various ways such as drawing using ink, washing fine objects and structures, scalpels, etc. In the embodiments described below, A fluid ejecting apparatus suitable for installation at the distal end of a catheter used for the purpose of inserting and removing a thrombus or the like, or a fluid ejecting apparatus suitable for incising or excising living tissue will be described as an example. Therefore, the fluid used in the embodiment is water or physiological saline, and hereinafter, these fluids are collectively referred to as a liquid.
(Embodiment 1)

  FIG. 1 is an explanatory diagram illustrating an example of a schematic configuration of the fluid ejecting apparatus according to the first embodiment. In FIG. 1, a fluid ejecting apparatus 100 contains a liquid as a basic configuration and includes a drive control unit 110 including an infusion bag as a fluid supply unit that supplies the liquid, a fluid ejecting unit 10 that changes the liquid into a pulsation, And a tube 80 that communicates the drive control unit 110 and the fluid ejection unit 10. The fluid ejecting unit 10 changes the liquid into a pulsation and ejects the droplet 200 as a droplet 200 at high speed.

  The drive control unit 110 includes a drive waveform generation circuit unit and a drive control circuit unit (not shown), and an adjustment device that adjusts the drive waveform in accordance with conditions such as the hardness of the surgical part.

Next, the fluid ejecting apparatus according to this embodiment will be described with reference to FIGS.
2 is a cross-sectional view of the fluid ejecting unit according to the first embodiment cut vertically along the cross-sectional central axis S, and FIG. 3 is a cross-sectional view of the cross-sectional central axis S cut horizontally (cut along the AA direction in FIG. 2). 4 (a) is a front view viewed from the front end direction of the fluid ejecting section 10, FIG. 4 (b) is a cross-sectional view showing a BB cut surface of FIG. 2, and FIG. 4 (c) is FIG. It is sectional drawing which shows CC cut surface. 2 to 4, the fluid ejecting unit 10 includes a plurality of variable volume chambers therein.

The plurality of variable volume chambers include a variable volume chamber 21 on the distal end side that communicates with the outlet flow path 31 of the fluid ejecting unit 10 (hereinafter simply referred to as a variable volume chamber 21), and an inlet flow path 37 with respect to the variable volume chamber 21. The rear side variable volume chambers 22 and 23 (hereinafter simply referred to as variable volume chambers 22 and 23) disposed on the side.
In addition, although the three variable volume chambers are illustrated in FIG. 2 as an example, it may be configured to include two or four or more.

  In the fluid ejecting unit 10, a diaphragm 40 is fixed to the surface of a thin plate-like spacer 61 formed along the central axis S of the cross section, and a diaphragm 41 is fixed to the back surface thereof. As shown in FIG. 3, the spacer 61 is formed with openings 32, 34, and 36 each having a substantially square planar shape at each of the variable volume chambers 21 to 23. The openings 32, 34, and 36 are sealed with diaphragms 40 and 41, and fluid chambers 62, 63, and 64 are configured in which the diaphragm 40 is an upper lid, the diaphragm 41 is a lower lid, and the spacer 61 is a side wall ( (See also FIG. 4 (b)).

  Further, a slit is provided on the tip 11 side of the spacer 61, and an outlet channel 31 is formed in which the diaphragm 40 is an upper lid, the diaphragm 41 is a lower lid, and the spacer 61 is a side wall (see FIG. 4A). ). The spacer 61 is provided with slits between the opening 32 and the opening 34, and between the opening 34 and the opening 36. The diaphragm 40 is an upper lid, the diaphragm 41 is a lower lid, and the spacer 61 is a side wall. Communication paths 33 and 35 are formed. In addition, a slit is also provided at the other end of the opening 36 to form an inlet channel 37 in which the diaphragm 40 is an upper lid, the diaphragm 41 is a lower lid, and the spacer 61 is a side wall.

  As described above, the outlet channel 31 constituted by the spacer 61 and the diaphragms 40 and 41, the communication channels 33 and 35, the inlet channel 37, and the cross-sectional shape perpendicular to the liquid flow direction of the fluid chambers 62 to 64 (see FIG. 4 (a) to 4 (c) are square, and the cross-sectional areas of the outlet channel 31, the communication channels 33 and 35, and the inlet channel 37 are much smaller than the cross-sectional areas of the fluid chambers 62 to 64.

  As shown in FIG. 3, the spacer 61 includes four corners 32a on the inner side wall of the opening 32 (fluid chamber 62), four corners 34a on the inner side wall of the opening 34 (fluid chamber 63), and The corners 36a at the four corners of the inner side wall of the opening 36 (fluid chamber 64) are smoothly rounded.

  Further, as shown in FIG. 3, in the communication passage 33, the width of the communication portion with the opening portion 32 (fluid chamber 62) on the distal end side is larger than the width of the communication portion with the opening portion 34 (fluid chamber 63). The communication passage 35 is set such that the width of the communication portion with the opening 34 (fluid chamber 63) is larger than the width of the communication portion with the opening 36 (fluid chamber 64).

  Similarly, also in the inlet channel 37, it is more preferable that the width of the communicating portion with the opening 36 (fluid chamber 64) is set larger than the width on the tube 80 side.

  In the outlet channel 31, in order to obtain the liquid nozzle effect, it is desirable that the cross-sectional area of the communication portion with the fluid chamber 62 be smaller than the cross-sectional area of the communication portion with the fluid ejection opening 30. In consideration of the fluidity of the liquid from the chamber 62 and the stabilization of the droplet ejection direction, the side wall is formed to be parallel to the central axis S of the cross section.

  The cross-sectional area of the communication passage 33 is made uniform, the communication portion with the fluid chamber 62 is rounded to widen the cross-sectional area, and the cross-sectional area of the communication passage 35 is made uniform, and the communication portion with the fluid chamber 63 is rounded. Similarly, the cross-sectional area may be widened, and similarly, the cross-sectional area of the inlet channel 37 may be uniform, and the communication area with the fluid chamber 64 may be rounded to widen the cross-sectional area.

  The spacer 61 may have a configuration in which the spacer 61a and the spacer 61b are separately formed on both sides of the central axis S of the cross section and disposed horizontally, and the spacer 61a and the spacer 61b are connected outside the both ends of the fluid ejecting unit 10. Alternatively, after the upper frame 71 and the lower frame 81 are fixed, the connection portion may be cut.

When the spacer 61 is integrally formed of the spacer 61a and the spacer 61b, the width dimension and the mutual position of the outlet channel 31, the fluid chambers 62 to 64, the communication channels 33 and 35, and the inlet channel 37 are accurately formed. In addition, since the height dimension is determined by the thickness of the spacer 61, variations due to the dimension of the liquid flow rate can be suppressed.
Further, as a means for forming the spacer 61, press working, etching, or the like can be adopted.

  The inner wall surfaces of the fluid chamber 62 and the outlet channel 31 are subjected to hydrophilic treatment. The hydrophilic treatment is performed to prevent bubbles from adhering to and staying between the flowing liquid and the inner wall surface. Therefore, it is more preferable to apply a hydrophilic treatment to all of the wall surfaces in which the liquid flows, including the fluid chamber 62 and the outlet channel 31.

  Piezoelectric elements 51, 53, and 55 are formed in close contact with the outer surface of the diaphragm 40 that faces each fluid chamber. The piezoelectric elements 51, 53, 55 are formed in a range smaller than the plane area of the openings 32, 34, 36, respectively.

  In addition, piezoelectric elements 52, 54, and 56 are formed in close contact with the outer surface of the diaphragm 41 that faces each fluid chamber. The piezoelectric elements 52, 54 and 56 are formed in a range smaller than the plane area of the openings 32, 34 and 36, respectively.

  The piezoelectric elements 51 to 56 are configured by laminating a lower electrode, a piezoelectric thin film, and an upper electrode from the diaphragm surface, and the materials of the piezoelectric thin film are the same and the polarization directions are matched.

  In addition, the lower electrodes and the upper electrodes of each piezoelectric element are wired so that voltages having the same potential are applied (not shown).

  On the surface of the diaphragm 40 on which the piezoelectric elements 51, 53, and 55 are formed, an upper frame 71 that is a part of one of the housings is closely attached and fixed. The upper frame 71 is provided with spaces 72 to 74 that can tightly fix the periphery of the driving range of the diaphragm 40, and the spaces 72 to 74 are sealed by the diaphragm 40 and the upper frame 71.

  In addition, a lower frame 81 which is the other part of the casing is closely fixed to the surface of the diaphragm 41 on which the piezoelectric elements 52, 54 and 56 are formed. The lower frame 81 is provided with spaces 82 to 84 so that the periphery of the driving range of the diaphragm 41 can be tightly fixed. Accordingly, the spaces 82 to 84 are sealed with the diaphragm 41 and the lower frame 81.

  Here, the spacer 61, the diaphragm 40, and the upper frame 71, and the spacer 61, the diaphragm 41, and the lower frame 81 are closely fixed to each other using a bonding technique such as adhesive fixing, anodic bonding, brazing, welding, etc. 10 is configured.

  The fluid ejecting unit 10 has a casing formed of an upper frame 71 and a lower frame 81 and has a cylindrical shape, and the distal end portion 11 is smoothly rounded into a hemispherical shape. The insertion resistance when inserting is reduced.

  Further, a tube fitting portion 75 is provided at the base end portion 12 of the fluid ejecting portion 10, and a tube 80 is fitted to the tube fitting portion 75 and communicated with the inlet flow path 37. The diameter of the tube 80 is set to be approximately equal to the diameter of the fluid ejecting unit 10 and is set so that one of them does not protrude in the radial direction.

  Next, the outline of the liquid flow in the fluid ejecting apparatus 100 according to the present embodiment will be briefly described. The drive control unit 110 includes a liquid container and a pressure generation unit (both not shown) connected to the liquid container. The pressure generation unit is connected to deliver a liquid to the tube 80. The liquid accommodated in the liquid container is supplied to the inlet channel 37 through the tube 80 at a constant pressure by the pressure generator. Further, the liquid is ejected from the fluid ejection opening 30 through the fluid chamber 64, the communication path 35, the fluid chamber 63, the communication path 33, the fluid chamber 62, and the outlet channel 31.

  Note that the liquid container is separated from the drive control unit 110 and disposed at a high position with respect to the fluid ejecting unit 10, and the pressure difference generated by the difference in the position head of the liquid container and the fluid ejecting unit 10 is utilized. A configuration may be adopted in which the liquid is allowed to flow into the fluid ejecting unit 10 at a constant pressure.

  Next, the liquid ejection operation in the present embodiment will be described with reference to FIG. Droplet ejection by the fluid ejection unit 10 may be referred to as an inertance L1 on the inlet channel side (sometimes referred to as a combined inertance L1 on the inlet channel side) and an inertance L2 on the outlet channel side (synthetic inertance L2 on the outlet channel side). ).

First, inertance will be described.
The inertance L is expressed by L = ρ × h / S, where ρ is the density of the fluid, S is the cross-sectional area of the flow path, and h is the length of the flow path. When the pressure difference in the flow path is ΔP and the flow rate of the fluid flowing through the flow path is Q, the relationship of ΔP = L × dQ / dt is derived by modifying the equation of motion in the flow path using the inertance L. It is.

That is, the inertance L indicates the degree of influence on the time change of the flow rate. The larger the inertance L, the less the time change of the flow rate, and the smaller the inertance L, the greater the time change of the flow rate.
In addition, the combined inertance related to the parallel connection of a plurality of flow paths and the series connection of a plurality of flow paths having different shapes is obtained by combining the inertance of individual flow paths in the same way as the parallel connection or series connection of inductances in an electric circuit. Can be calculated.

  In the present embodiment, by providing a plurality of variable volume chambers, for the variable volume chamber 21, the inertance in the range of the outlet flow path 31 is the outlet flow side inertance L2, and the range from the communication path 33 to the inlet flow path 37 is It can be considered as an inlet channel side synthetic inertance L1 on the inlet channel side.

  Further, for the variable volume chamber 22, the range of the communication path 33 can be considered as the outlet flow path inertance L2, and the range of the communication path 35 to the inlet flow path 37 can be considered as the inlet flow path side synthetic inertance L1.

  For the variable volume chamber 23, the range of the communication path 35 can be considered as the outlet flow path side inertance L2, and the range of the inlet flow path 37 can be considered as the inlet flow path side synthetic inertance L1.

In addition, since the tube 80 connected to the fluid ejection unit 10 has flexibility, it is deleted from the calculation of the inertance L1 on the inlet channel side.
In this embodiment, in each volume variable chamber, the flow rate of the inlet channel 37, the communication channels 33 and 35, and the outlet channel 31 is such that the inertance L1 on the inlet channel side is larger than the inertance L2 on the outlet channel side. Set the road length and cross-sectional area.

Next, the operation of the fluid ejecting unit 10 will be described. This will be described with reference to FIGS. First, since the individual basic operations of the respective variable volume chambers are the same, the variable volume chamber 21 will be described as an example. The volume variable chamber 21 applies the drive waveform formed by the drive waveform generation circuit unit included in the drive control unit 110 to the piezoelectric elements 51 and 52 from the drive control circuit unit.
FIG. 5 is an explanatory diagram schematically showing an example of the drive waveform and the displacement of the diaphragm in the present embodiment. (A) represents the drive waveform, and (b) represents the displacement amount of the diaphragm (which can be replaced with the volume change amount of the fluid chamber). The fluid ejection unit drive voltage P2 in this example is composed of a pulsation unit configured by an integer number of continuous waveforms of sine waves whose phase starts from −π / 2, and a rest unit (represented by a rest time I). Shall. The waveform of the pulsation part is represented by an amplitude A, a period T, and the number n of continuous sine waves. The waveform of the pulsation portion is exemplified for a burst wave.

  The fluid is supplied from the inlet channel 37 to the fluid chamber 62 through the fluid chamber 64, the communication path 35, the fluid chamber 63, and the communication path 33. Here, if the drive signal shown in FIG. 5A is input to both of the piezoelectric elements 51 and 52 and the piezoelectric elements 51 and 52 are charged and the piezoelectric elements 51 and 52 contract suddenly, the diaphragms 40 and 41 are The fluid chamber 62 is suddenly displaced in a convex shape in the direction of reducing the volume. As a result, the pressure in the fluid chamber 62 rises rapidly to reach several atmospheres if the inertances L1 and L2 on the inlet channel side and the outlet channel side have a sufficient size.

Since this pressure is much larger than the pressure generated by the pressure generating portion applied to the inlet channel 37, the inflow of liquid from the inlet channel side into the fluid chamber 62 is reduced by the pressure, and the pressure from the outlet channel 31 is reduced. Outflow increases. However, since the combined inertance L1 on the inlet channel side is larger than the inertance L2 on the outlet channel side, the increase amount of the outflow from the outlet channel 31 is smaller than the decrease amount of the liquid inflow from the inlet channel 37 into the fluid chamber 62. Is big.
As a result, pulsed fluid discharge, that is, high-speed droplets 200 are ejected in pulses from the fluid ejection opening 30 through the outlet channel 31.

  On the other hand, after the volume of the fluid chamber 62 is reduced, the piezoelectric elements 51 and 52 are discharged and returned to the initial state as the fluid ejection unit drive voltage P2 decreases. The fluid chamber 62 is in a low pressure or vacuum state after the pressure rises due to the interaction between the decrease in the amount of liquid inflow from the inlet channel side and the increase in the outflow of liquid from the outlet channel 31, and the liquid flows into the fluid chamber from the inlet channel side. Flows into 62. Thereafter, if the piezoelectric elements 51 and 52 are contracted, high-speed pulsed droplets can be continuously ejected from the fluid ejection opening 30.

  In the present embodiment, two variable volume chambers 22 and 23 are provided on the rear stage side with respect to the variable volume chamber 21 on the front end side. Here, a drive waveform having the same phase is applied to at least the front-end variable volume chamber 21 (that is, the piezoelectric elements 51 and 52) and the rear-stage variable volume chamber 22 (that is, the piezoelectric elements 53 and 54). Then, the piezoelectric elements 51 to 54 are contracted or released at the same timing. That is, the volumes of the fluid chamber 62 and the fluid chamber 63 are reduced at the same timing and returned to the initial volume at the same timing. A drive waveform is also applied to the volume variable chamber 23 subsequent to the volume variable chamber 22 at the same timing.

  In this case, the volume of the fluid chamber 62 and the fluid chambers 63 and 64 are changed at the same timing, so that the rear-stage volume variable chamber becomes a liquid supply mechanism with respect to the front-stage volume variable chamber. The fluid resistance against the back flow of the liquid when the volume is changed is large. The variable volume chamber 22 can be described as a front stage of the variable volume chamber 23, and the variable volume chamber 23 can be replaced with a subsequent stage of the variable volume chamber 22.

Therefore, according to the first embodiment described above, the volume variable chamber 22 on the rear stage side sends the liquid whose pressure is increased into the fluid chamber 62 with respect to the volume variable chamber 21 on the fluid ejection opening 30 side, and at the same time the fluid chamber 62. It becomes a fluid resistance component against the reverse flow of the liquid when the volume of the liquid is reduced.
In particular, when the instrument itself is required to have a thin shape as in brain surgery, the amount of reduction of the fluid chamber of each variable volume chamber is small, so that a sufficient amount of liquid is supplied into the variable volume chamber 21 (fluid chamber 62). It is thought that it is not possible. However, sufficient fluid supply can be performed by providing the latter-stage variable volume chamber 22 and supplying liquid to the variable volume chamber 21.

  Further, in the fluid chamber 62, when the volume is reduced, a reverse flow is generated on the inlet channel side, so that droplets of an appropriate size and size may not be ejected in a pulse shape. Therefore, there is an effect that the volume of the fluid chamber 63 of the subsequent volume variable chamber 22 can be reduced to generate a fluid resistance component, and pulsed droplet ejection can be performed.

The fluid chambers 62 to 64, the outlet channel 31, the inlet channel 37, and the communication channels 33 and 35 form upper and lower lids with the diaphragms 40 and 41 and side walls with the spacers 61 (spacers 61 a and 61 b). Even in the configuration in which a plurality of variable volume chambers are provided, the number of components can be reduced, and the fluid ejecting unit can be downsized.
In addition, it is difficult to reduce the diameter of the outlet channel 31, the inlet channel 37, and the communication passages 33 and 35 with holes having a circular cross-sectional shape. By providing, the outlet channel 31, the inlet channel 37, and the communication paths 33 and 35 can be easily formed.

  In the present embodiment, the inlet channel 37, the communication passages 33 and 35, the fluid chambers 62 to 64, and the outlet channel 31 are arranged on a substantially straight line. When a flow path that bends to any one of the outlet flow path 31, the fluid chambers 62, 63, 64, the communication paths 33, 35, and the inlet flow path 37 is configured, fluid resistance is generated at the bent portion. However, by arranging each of the flow paths on a straight line, the fluid resistance between the flow paths can be suppressed, and the liquid can be smoothly supplied to the fluid chamber 62 on the distal end side.

  Furthermore, even if the flow path is arranged in a straight line, a cylindrical fluid injection unit 10 can be formed even in a structure including a plurality of variable volume chambers. There is an effect that the fluid ejecting unit 10 can be provided.

  In addition, the side wall of the flow path of the fluid ejecting unit 10 can easily form the thin plate-like spacer 61 including the opening that constitutes the fluid chamber by a punching process, an etching process, and the like. In addition, the cross-sectional shape of each of the above-described flow paths constituting the upper lid and the lower lid by the lower frame 81 is a quadrangle. At this time, the height of the cross-sectional area of each flow path is constant with the thickness of the spacer 61, and it can be easily set to a desired cross-sectional area by changing the width dimension of the side wall. There is an effect that can be easily done.

  In the present embodiment, the corners of the inner side walls of the fluid chambers 62 to 64 are smoothly rounded. In a device that reduces the volume of a fluid chamber with a diaphragm and ejects fluid in the fluid chamber, if there are minute bubbles in the fluid chamber, the pressure in the fluid chamber may not be sufficiently increased. It tends to stay in the corner of the room. Therefore, by smoothly rounding the corners of the inner side walls of the fluid chambers 62 to 64, it is possible to prevent the bubbles from staying and to easily discharge the bubbles to the outside during fluid ejection.

  Further, the width of the communication passages 33 and 35 on the side where the liquid flows into the fluid chambers 62 and 63 is made larger than the width on the side where the liquid flows out of the fluid chambers 62 and 63. In the flow direction of the fluid, the fluid can be easily flowed by a diffusion effect by reducing the cross-sectional area of the communication passages 33 and 35 on the outflow side than the inflow side of the fluid. Make fluid difficult to flow. Accordingly, with such a configuration, the flow from the rear-stage fluid chamber to the front-stage fluid chamber is promoted, and the flow from the front-stage fluid chamber to the rear-stage fluid chamber (that is, backflow) is suppressed. Can do.

The fluid ejecting unit 10 has a cylindrical shape, the diameter of the fluid ejecting unit 10 and the diameter of the tube 80 are substantially equal, and the tip 11 of the fluid ejecting unit 10 is rounded into a substantially hemispherical shape.
In this way, it can be inserted into the inside of a narrow tube (blood vessel or the like) having the same diameter as that of the tube 80 and can be easily removed and removed without damaging the inner wall of the thin tube and removing thrombus and the like. Can be adapted to the surgery.

Further, all of the fluid chambers 62, 63, 64, or at least the inner wall of the fluid chamber 62 communicating with the outlet channel 31 are subjected to hydrophilic treatment.
When hydrophilic treatment is performed on the inner wall of the fluid chamber, bubbles are less likely to stay on the inner wall surface, and when pressurized, the bubbles can be discharged from the fluid ejection opening 30 together with the fluid. There is an effect that the pressure can be increased.

In the present embodiment, the volume change timings of the variable volume chambers 21, 22, and 23 are matched. In this way, the time at which the pressure waves generated in the respective variable volume chambers reach the fluid ejection openings 30 can be made simultaneously, and strong and sharp droplet ejection can be realized from the fluid ejection openings 30. .
(Modification of Embodiment 1)

  In this modified example, at least one of the plurality of volume variable chambers excluding the volume variable chamber communicating with the fluid ejection opening (exit flow path) among the plurality of volume variable chambers is a reservoir for storing liquid. Features. Although not shown, the case where the variable volume chamber 22 is used as a reservoir will be described with reference to FIG. The configuration of this example includes a configuration in which the configuration of the variable volume chamber 22 is the same as that in the first embodiment, and a drive signal is not input, and a configuration in which the piezoelectric elements 53 and 54 are not added. In any configuration, the fluid chamber 63 is a space in which a liquid stays.

  In such a configuration, when the volume of the fluid chamber 62 on the front end side is reduced and then opened, the liquid may slightly flow to the outlet channel 31, and this liquid collides with the next ejected droplet. An appropriate droplet shape may not be formed. Therefore, by disposing the latter-stage variable volume chamber as a reservoir, the reservoir can be used as a buffer zone for liquid flow, and the flow of liquid after pressure release can be suppressed. At this time, if the volume of the fluid chamber 64 of the subsequent volume variable chamber 23 is restored, it is more effective.

In addition to the variable volume chamber 22, the subsequent variable volume chamber 23 may be used as a reservoir, and both the variable volume chambers 22 and 23 may be used as reservoirs.
(Embodiment 2)

Next, the operation of the fluid ejecting unit according to the second embodiment will be described with reference to the drawings. The second embodiment is different from the first embodiment described above in that the phase of the drive signal of each volume variable chamber is matched to match the volume change timing of the fluid chamber, whereas the volume of the rear stage is different from the volume variable chamber of the previous stage. It is characterized in that the phase of the drive signal of the variable chamber is advanced. Since the structure of the fluid ejecting unit is the same as that of the first embodiment (see FIGS. 2 to 4), description thereof is omitted.
FIG. 6 is an explanatory diagram schematically illustrating an example of a driving waveform and a displacement of the diaphragm according to the second embodiment. (A) represents the drive waveform, and (b) represents the displacement of the diaphragm. The relationship between the variable volume chamber 21 and the variable volume chamber 22 will be described as an example.

  The drive waveforms applied to each of the variable volume chamber 21 and the variable volume chamber 22 have the same amplitude A, period T, number of continuous sine waves n, and rest time I, but the drive waveforms applied to the variable volume chamber 21 are the same. In contrast, the phase of the drive waveform applied to the variable volume chamber 22 is advanced.

  In this way, the time at which the pressure waves generated in the respective variable volume chambers reach the fluid ejection openings 30 can be made simultaneously, and strong and sharp droplet ejection can be realized from the fluid ejection openings 30. .

The relationship between the variable volume chamber 22 and the variable volume chamber 23 is the same. If the phase of the drive waveform applied to the variable volume chamber 23 precedes the variable volume chamber 22, the inside of the fluid chamber 63 of the variable volume chamber 22 will be described. There is an effect that the pressurized liquid is fed into the pressure chamber and the pressure in the variable volume chamber 21 on the tip side can be further increased.
(Embodiment 3)

Next, the operation of the fluid ejecting unit according to the third embodiment will be described with reference to the drawings. The third embodiment is different from the first embodiment in that the phase of the drive vibration of each volume variable chamber is matched to match the volume change timing of the fluid chamber, whereas the volume of the rear stage is different from the volume variable chamber of the previous stage. It is characterized in that the phase of the drive signal of the variable chamber is delayed. Since the structure of the fluid ejecting unit is the same as that of the first embodiment (see FIGS. 2 to 4), description thereof is omitted.
FIG. 7 is an explanatory diagram schematically illustrating an example of a drive waveform and a displacement of the diaphragm according to the third embodiment. (A) represents the drive waveform, and (b) represents the displacement of the diaphragm. The relationship between the variable volume chamber 21 and the variable volume chamber 22 will be described as an example.

  The drive waveforms applied to the variable volume chamber 21 and the variable volume chamber 22 have the same amplitude A, period T, number of consecutive sine waves n, and rest time I, but with respect to the drive waveforms applied to the variable volume chamber 21. Thus, the phase of the drive waveform applied to the variable volume chamber 22 is delayed.

  In this way, since the pressure wave reaches the fluid ejection opening 30 one after another, relatively slow droplet ejection continues for a long time, which is effective for cutting soft tissue.

  The relationship between the volume variable chamber 22 and the volume variable chamber 23 is also the same. If the phase of the drive waveform applied to the volume variable chamber 23 is delayed with respect to the volume variable chamber 22, the inside of the fluid chamber 63 of the volume variable chamber 22 will be described. There is an effect that the pressurized liquid is fed into the pressure chamber and the pressure in the variable volume chamber 21 on the tip side can be further increased.

The preceding time or delay time (that is, the fluid chamber volume change timing) of the drive waveform application described in the above-described second and third embodiments is within a half cycle of the drive signal.
By doing so, the back flow of the liquid to the subsequent fluid chamber when the volume of the fluid chamber fluid chamber 62 is reduced is suppressed, the internal pressure of the fluid chamber 62 is increased, and high-speed droplet ejection is promoted. In addition, it is possible to suppress generation of reflected waves of the liquid and eject droplets having an appropriate droplet shape and size in a pulse shape.

  In the above-described second and third embodiments, the timing of applying the drive waveforms of the subsequent volume variable chambers 22 and 23 is advanced or delayed with respect to the previous volume variable chamber. Each of the numbers 22 and 23 may be a combination of delaying, leading, or matching the timing with respect to the variable volume chamber 21.

  In the first embodiment described above, an example in which the configuration of the plurality of variable volume chambers is the same is shown. However, in the variable volume chambers 21, 22, and 23, the plane sizes of the fluid chambers can be changed from each other. The piezoelectric element provided in the variable volume chamber may be provided in either the diaphragm 40 or the diaphragm 41. These combination settings can be appropriately selected according to the ejection speed and the droplet size.

FIG. 3 is an explanatory diagram illustrating an example of a schematic configuration of the fluid ejecting apparatus according to the first embodiment. FIG. 3 is a cross-sectional view of the fluid ejecting apparatus according to the first embodiment, the cross-section central axis S being cut perpendicularly. FIG. 3 is a cross-sectional view of the fluid ejection device according to the first embodiment, in which the cross-section central axis S is cut horizontally. (A) is the front view visually recognized from the front-end | tip direction of the fluid injection part, (b) is sectional drawing which shows the BB cut surface of FIG. 2, (c) is sectional drawing which shows the CC cut surface of FIG. It is explanatory drawing which shows typically an example of the drive waveform in Embodiment 1, and the displacement of a diaphragm, (a) represents a drive waveform, (b) represents the displacement amount of a diaphragm. It is explanatory drawing which shows typically an example of the drive waveform which concerns on Embodiment 2, and the displacement of a diaphragm, (a) represents a drive waveform, (b) represents the displacement amount of a diaphragm. It is explanatory drawing which shows typically an example of the drive waveform which concerns on Embodiment 3, and the displacement of a diaphragm, (a) represents a drive waveform, (b) represents the displacement amount of a diaphragm.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Fluid injection part, 21, 22, 23 ... Variable volume chamber, 30 ... Fluid injection opening part, 31 ... Outlet flow path, 33, 34 ... Communication path, 37 ... Inlet flow path, 40, 41 ... Diaphragm, 62- 64: fluid chamber, 80: tube, 100: fluid ejection device.

Claims (14)

A fluid ejecting apparatus that ejects fluid in a pulse form from a fluid ejecting opening by reducing the volume of a fluid chamber provided inside a variable volume chamber by a diaphragm,
A tube for supplying a fluid to the fluid chamber;
A fluid ejecting portion disposed at the tip of the tube,
The fluid ejecting section includes a plurality of variable volume chambers in series via a communication path between an inlet channel communicating with one end of the tube and an outlet channel communicating with a fluid ejection opening for ejecting fluid. Arranged,
A fluid ejection characterized in that, in a cross-sectional area perpendicular to a fluid flow direction, the cross-sectional areas of the communication path, the outlet channel, and the inlet channel are smaller than the cross-sectional area of the fluid chamber. apparatus. The fluid ejection device according to claim 1,
A plurality of the variable volume chambers are provided in each of the variable volume chambers, the fluid passages communicating with the fluid chambers, and the outlet flow that communicates the fluid ejection opening and one of the fluid chambers. A thin plate-like spacer that forms a channel and a side wall of each of the inlet channels, a diaphragm that is in close contact with both front and back surfaces of the spacer, and a piezoelectric element that is provided on the outer surface of the fluid chamber of the diaphragm; A fluid ejecting apparatus comprising: The fluid ejection device according to claim 1 or 2,
The fluid ejecting apparatus, wherein the inlet channel, the fluid chamber, the communication channel, and the outlet channel are arranged on a substantially straight line. In the fluid ejection device according to any one of claims 1 to 3,
A fluid ejecting apparatus, wherein a cross-sectional shape perpendicular to a fluid flow direction of the inlet channel, the communication channel, and the outlet channel is a quadrangle. The fluid ejection device according to any one of claims 1 to 4,
A fluid ejecting apparatus, wherein corners of an inner side wall of the fluid chamber are smoothly rounded. In the fluid ejection device according to any one of claims 1 to 5,
The fluid ejecting apparatus according to claim 1, wherein a width of a side of the communication passage where the fluid flows into the fluid chamber is larger than a width of the side of the fluid flowing out of the fluid chamber. The fluid ejection device according to any one of claims 1 to 6,
The fluid ejecting apparatus according to claim 1, wherein the fluid ejecting section has a cylindrical shape, and the diameter of the fluid ejecting section is substantially equal to the diameter of the tube. The fluid ejection device according to claim 7, wherein
A fluid ejecting apparatus, wherein a tip end portion of the fluid ejecting section in the direction of the fluid ejecting opening is rounded into a substantially hemispherical shape. The fluid ejection device according to any one of claims 1 to 8,
At least one of the plurality of variable volume chambers, excluding the variable volume chamber communicating with the fluid ejection opening, is a reservoir for retaining fluid. The fluid ejection device according to any one of claims 1 to 9,
Among the plurality of variable volume chambers, at least an inner wall of a fluid chamber communicating with the fluid ejection opening is subjected to a hydrophilic treatment. The fluid ejection device according to any one of claims 1 to 10,
The fluid ejecting apparatus according to claim 1, wherein the volume change timings of the fluid chambers of the plurality of variable volume chambers are matched. The fluid ejection device according to any one of claims 1 to 10,
The fluid ejecting apparatus according to claim 1, wherein, among the plurality of variable volume chambers, the variable volume chamber on the outlet flow path side is preceded by a volume change timing of the fluid chamber in the variable volume chamber on the inlet flow path side. The fluid ejection device according to any one of claims 1 to 10,
A fluid ejecting apparatus that delays the volume change timing of the fluid chamber of the volume variable chamber on the inlet flow path side with respect to the volume variable chamber on the fluid ejection opening side among the plurality of variable volume chambers. The fluid ejection device according to claim 12 or 13,
The fluid ejecting apparatus according to claim 1, wherein a leading time or a delay time of the volume change timing is within a half cycle of the driving signal.

Images