JP2013213422A - Liquid injection device and method for controlling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid injection device that can provide stable liquid injection from right after being started, and to provide a method for controlling the liquid injection device.SOLUTION: A liquid injection device includes: a pulsating flow generation part 20 that injects liquid in a pulse-shape; a liquid supply part 10 that pumps liquid by periodical drive and supplies liquid to the pulsating flow generation part 20; a pressure variation absorbing part 5 that absorbs a pressure variation by a volume change in liquid disposed between the pulsating flow generation part 20 and the liquid supply part 10; and a driving control part 15 that performs drive and control of the pulsating flow generation part 20 and the liquid supply part 10 based on a designated flow rate. When the designated flow rate is defined as a second flow rate and a flow rate where an additional flow rate is imposed on the second flow rate is defined as a first flow rate, the drive control part 15 starts the pulsating generation part 20 and supplies the liquid of the first flow rate from the liquid supply part 10 for a specific time, and after the specific time, supplies liquid of the second flow rate from the liquid supply part 10.

Description

  The present invention relates to a fluid ejecting apparatus that ejects liquid in pulses and a control method for the fluid ejecting apparatus.

  2. Description of the Related Art Conventionally, a technique for cutting or excising an object by ejecting a liquid in pulses is known. For example, in the medical field, as a fluid ejecting apparatus as a surgical tool for incising or excising a living tissue, it has a fluid chamber whose volume is changed by driving a volume changing means, and converts the liquid into a pulsating flow and pulses from the nozzle. Proposed fluid ejection device composed of a pulsating flow generating section that jets at high speed, a fluid supply section that supplies liquid to the pulsating flow generation section, and a fluid supply tube that communicates the pulsating flow generation section and the fluid supply section (For example, refer to Patent Document 1).

JP 2008-82202 A

  The pulsating flow generation unit described above reduces the volume of the fluid chamber by driving the volume changing means, converts the liquid into a pulsating flow, and jets the liquid at high speed in a pulsed manner. Here, in order to eject the liquid from the nozzle, it is necessary to always supply a necessary and sufficient amount of liquid to the fluid chamber so that the fluid chamber is filled with the liquid. For this reason, in the technique of injecting a pulsed jet, a volume-changing pump (for example, a piston pump) capable of ensuring a sufficient flow rate as a fluid supply unit for supplying liquid to the fluid chamber, Peristaltic pumps (such as tube pumps) are used.

  However, the volume-changing type pump and the peristaltic pump tend to cause periodic fluctuations in the supply pressure of the liquid, and thus there is a problem that the operational feeling of the fluid ejecting apparatus is easily impaired. This is because if the supply pressure of the liquid fluctuates, the amount of liquid ejected from the nozzle fluctuates, so that the incision ability fluctuates or the reaction force felt by the operator when the liquid is ejected varies. It is to do. For this reason, it is necessary to supply a liquid with a stable flow rate to the pulsating flow generation unit in the technique of ejecting the liquid in pulses. At this time, in order to suppress periodic fluctuations in the liquid supply pressure, there is a method in which a pressure fluctuation absorbing portion that absorbs pressure fluctuations by volume change is arranged in the flow path, but the fluid ejecting apparatus is used. In such a case, the pressure fluctuation absorbing member is disposed in the flow path, so that there is an adverse effect that a liquid having a stable flow rate cannot be supplied to the pulsating flow generation unit. Specifically, when injecting liquid from the nozzle, driving the pulsating flow generation unit increases the pressure inside the pulsating flow generation unit, increasing the flow resistance of the flow channel, and absorbing pressure fluctuations. The liquid pressure in the member also increases, and the pressure fluctuation absorbing member is deformed to expand. As a result, when the pulsating flow generation unit is activated, the amount of liquid supplied to the pulsating flow generation unit temporarily decreases, and it takes time until a stable steady flow rate is obtained. There is a problem that a desired stable fluid ejection amount cannot be secured in a period in which the liquid supply amount is reduced from the steady flow rate. Here, the steady flow rate means a liquid supply amount supplied from the fluid supply unit at a substantially constant flow rate when the pulsating flow generation unit is continuously driven.

  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 ejection device according to this application example includes a pulsating flow generation unit that ejects liquid in pulses, and a fluid that pumps liquid by periodic driving and supplies the liquid to the pulsating flow generation unit A pulsating flow generation unit and the fluid based on a specified flow rate; a supply unit; a pressure variation absorption unit configured to absorb pressure variation by a volume change disposed between the pulsating flow generation unit and the fluid supply unit; A drive control unit that performs drive control with the supply unit, and when the designated flow rate is a second flow rate and a flow rate obtained by adding an increased flow rate to the second flow rate is a first flow rate, the drive control unit Activates the pulsating flow generation unit, supplies the liquid at the first flow rate from the fluid supply unit for a predetermined time, and supplies the liquid at the second flow rate from the fluid supply unit after the predetermined time has elapsed. It is characterized by.

  According to this application example, it is possible to supply the stable liquid by absorbing the pressure fluctuation due to the periodic pumping of the fluid supply section by the volume change of the pressure fluctuation absorption section, and at the same time, when the pulsating flow generation section is started, By supplying a liquid having a first flow rate higher than the second flow rate from the supply unit, a temporary decrease in the amount of liquid supply to the pulsating flow generation unit due to the expansion of the pressure fluctuation absorption unit is suppressed. Since the fluid ejection amount from the pulsating flow generation unit can be made close to the second flow rate, the liquid can be ejected in pulses at a stable fluid ejection amount immediately after the activation of the pulsating flow generation unit.

  Application Example 2 In the fluid ejection device according to the application example, it is preferable that the drive control unit also activates the fluid supply unit when the pulsating flow generation unit is activated.

  According to this application example, it is possible to stop ejecting excess liquid while the liquid is not ejected in pulses, and at the same time, stably eject the fluid ejection amount immediately after activation of the pulsating flow generation unit. Can do.

  Application Example 3 In the fluid ejecting apparatus according to the application example described above, a fluid chamber for ejecting liquid into the pulsating flow generation unit in a pulse shape by changing the volume, information on the volume change amount of the volume change, and the volume Input means for inputting information on the repetition frequency of the change, and the drive control unit supplies the liquid at the first flow rate and the liquid at the first flow rate based on the information on the volume change amount and the volume change repetition frequency. It is preferable to determine one of the predetermined time to supply and the second flow rate.

  According to this application example, the fluid supply is based on the specified time and the increased flow rate determined from the information of the volume change amount of the volume change that affects the pressure increase at the start of the pulsating flow generation unit and the repetition frequency of the volume change. Since the part is driven, the supply flow rate can be increased with high accuracy, and the liquid can be stably ejected immediately after the start of the pulsating flow generation part. Further, it is not necessary for the operator (operator) to calculate and input the steady flow rate, the designated time and the increased flow rate every time, and the operability can be improved.

  Application Example 4 A control method for a fluid ejection device according to this application example includes a pulsating flow generation unit that ejects liquid in pulses and a liquid that is pumped by periodic driving so that the liquid is supplied to the pulsating flow generation unit. A fluid supply unit to supply, a pressure fluctuation absorption unit that absorbs pressure fluctuations by a volume change disposed between the pulsating flow generation unit and the fluid supply unit, and the pulsating flow generation unit based on a specified flow rate And a drive control unit that performs drive control with the fluid supply unit, wherein the designated flow rate is a second flow rate, and the increased flow rate is added to the second flow rate. When the flow rate is the first flow rate, the drive control unit activates the pulsating flow generation unit and supplies the liquid at the first flow rate for a predetermined time from the fluid supply unit. The fluid supply unit after the predetermined time has elapsed. Characterized in that it comprises a, and thereby supplying the liquid in the second flow rate.

  According to this application example, when the pulsating flow generation unit is activated, even when the pressure fluctuation absorption unit expands by supplying a liquid having a first flow rate higher than the second flow rate from the fluid supply unit, The liquid supply amount from the pulsating flow generation unit can be quickly brought close to the second flow rate by suppressing the decrease in the liquid supply amount to the flow generation unit, so that the liquid can be stably pulsed immediately after the pulsating flow generation unit is activated. Can be sprayed at high speed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. Sectional drawing which cut | disconnected the pressure fluctuation absorption part which concerns on Embodiment 1 along the flow direction of the liquid. Sectional drawing which cut | disconnected the pulsating flow generation part which concerns on Embodiment 1 along the injection direction of a liquid. FIG. 2 is a configuration explanatory diagram illustrating a schematic configuration of a control system according to the first embodiment. The graph which shows typically the injection flow volume when not performing control by Embodiment 1. FIG. FIG. 3 is a flow explanatory diagram illustrating a control method for the fluid ejection device according to the first embodiment. 3 is a graph schematically showing an injection flow rate when the control according to the first embodiment is performed. FIG. 9 is a flow explanatory diagram illustrating a control method for a fluid ejection device according to a modification of the first embodiment. The side surface fragmentary sectional view which shows the cut surface which cut | disconnected the pulsating flow generation part which concerns on Embodiment 2 in the orthogonal | vertical direction with respect to the diaphragm.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The fluid ejecting apparatus according to the present invention can be used in various ways such as drawing with ink, washing fine objects and structures, and a scalpel. In the embodiments described below, incision or excision of living tissue is performed. A fluid ejecting apparatus suitable for this will be described as an example. Therefore, the liquid used in the embodiment is a liquid such as water or physiological saline. 2, 3, and 9 described below are schematic views in which the vertical and horizontal scales of members or portions are different from actual ones for convenience of illustration.

(Embodiment 1)
FIG. 1 is a configuration explanatory view showing a fluid ejection device as a surgical instrument according to the present embodiment. In FIG. 1, a fluid ejecting apparatus 1 converts a liquid supply container 2 (hereinafter simply referred to as a container 2) that contains a liquid, a pump 10 as a fluid supply unit, and a liquid supplied from the pump 10 into a pulsating flow. And a pulsating flow generation unit 20 that injects in a pulsed manner. The pump 10 and the pulsating flow generator 20 are communicated with each other by a liquid supply tube 4 (hereinafter simply referred to as a tube 4). Furthermore, between the pump 10 and the pulsating flow generation unit 20, there is provided a pressure fluctuation absorption unit 5 that absorbs pressure fluctuations by volume change. The pulsating flow generation section 20 is connected to a thin pipe-shaped connection flow path pipe 90, and a nozzle 95 with a reduced flow path diameter is inserted into the distal end portion of the connection flow path pipe 90.

  As the pump 10, a volume-changing type pump (such as a piston pump or a diaphragm pump) or a peristaltic pump (such as a tube pump) that pumps liquid by periodic driving is used. At this time, since the liquid is pumped by the periodic driving of the pump 10, periodic pressure fluctuations occur. However, since the pressure fluctuation absorption unit 5 absorbs the pressure fluctuation due to the volume change, the liquid that has passed through the pressure fluctuation absorption unit 5 has a stable pressure.

  Further, the fluid ejection device 1 is provided with a drive control unit 15 for controlling the driving of the pump 10 and the pulsating flow generation unit 20. In FIG. 1, the drive control unit 15 is disposed at a position separated from the pump 10 and the pulsating flow generation unit 20, but may be configured as a drive control unit including the pump 10.

  When the fluid ejection device 1 is used as a surgical instrument, the pulsating flow generation unit activation switch 25 is disposed in the pulsating flow generation unit 20 in order to grasp and operate the pulsating flow generation unit 20. Note that the pulsating flow generation unit activation switch 25 may be disposed in the drive control unit 15 as a foot switch. The pulsation amount changeover switch 27 and the pulsation frequency changeover switch 28 are disposed in the drive control unit 15.

  First, the flow of the liquid in the fluid ejecting apparatus 1 will be briefly described. The liquid stored in the container 2 is sucked by the pump 10 and supplied to the pulsating flow generation unit 20 via the pressure fluctuation absorption unit 5 (see FIG. 2) and the tube 4. The pulsating flow generation unit 20 includes a fluid chamber 80 and a piezoelectric element 30 and a diaphragm 40 (both see FIG. 3) as volume changing means for changing the volume of the fluid chamber 80. Is driven to generate a pulsating flow by changing the volume of the fluid chamber 80, and the liquid is ejected in a pulsed manner at high speed via the connection flow channel tube 90 and the nozzle 95. Here, the pulsating flow means a liquid flow in which the flow direction of the liquid is constant and the flow rate or flow velocity of the liquid is accompanied by a periodic or irregular fluctuation. The pulsating flow includes an intermittent flow in which the flow and stop of the liquid are repeated. However, since the flow rate or flow rate of the liquid only needs to fluctuate periodically or irregularly, the pulsating flow is not necessarily an intermittent flow. Similarly, ejecting the liquid in a pulse form means ejecting the liquid in which the flow rate or moving speed of the ejected liquid is changed periodically or irregularly. An example of pulsed injection is intermittent injection in which liquid injection and non-injection are repeated. However, since the flow rate or movement speed of the liquid to be injected only needs to fluctuate periodically or irregularly, it is not always intermittent injection. Need not be.

Next, the structure of the pressure fluctuation absorber 5 according to this embodiment will be described.
FIG. 2 is a cross-sectional view of the pressure fluctuation absorber 5 according to the present embodiment cut along the liquid flow direction. The pressure fluctuation absorbing unit 5 includes an elastic wall 51 and an air bag 52 filled with air. When the pressure of the liquid passing through the pressure fluctuation absorbing unit 5 fluctuates, the pressure fluctuation absorbing unit 5 encloses the elastic wall 51 and air. The air bag 52 absorbs the pressure fluctuation by the volume change that is passive with respect to the fluctuation of the pressure of the liquid passing through the pressure fluctuation absorber 5. Note that either the elastic wall surface 51 or the air bag 52 filled with air may be used, or another configuration may be used as long as it has the same function.

Next, the structure of the pulsating flow generation unit 20 according to this embodiment will be described.
FIG. 3 is a cross-sectional view of the pulsating flow generation unit 20 according to the present embodiment cut along the liquid ejection direction. The pulsating flow generation unit 20 includes an inlet channel 81 that supplies liquid to the fluid chamber 80 from the pump 10 via the pressure fluctuation absorption unit 5 and the tube 4, and a piezoelectric element as a volume changing unit that changes the volume of the fluid chamber 80. 30 and the diaphragm 40, and an outlet channel 82 for sending liquid from the fluid chamber 80 to the fluid ejection opening 96.

  The diaphragm 40 is made of a disk-shaped thin metal plate, and the peripheral edge thereof is closely fixed by the lower case 50 and the upper case 70. The piezoelectric element 30 is a laminated piezoelectric element in the present embodiment, and one of both ends is fixed to the diaphragm 40 and the other is fixed to the bottom plate 60.

  The fluid chamber 80 is a space formed by a recess formed on the surface of the upper case 70 facing the diaphragm 40 and the diaphragm 40. An outlet channel 82 is opened at a substantially central portion of the fluid chamber 80. The upper case 70 and the lower case 50 are joined and integrated on the opposing surfaces. A connection channel pipe 90 having a connection channel 91 that communicates with the outlet channel 82 is fitted into the upper case 70, and a nozzle 95 is inserted into the tip of the connection channel pipe 90. The nozzle 95 is provided with a fluid ejection opening 96 whose flow path diameter is smaller than that of the outlet flow path 82. In addition, the upper case 70 is formed with an inlet channel 81 communicating with the fluid chamber 80, and the tube 4 is attached to the inlet channel 81.

  Next, the fluid discharge operation of the pulsating flow generation unit 20 in the present embodiment will be described with reference to FIGS. The fluid discharge of the pulsating flow generation unit 20 of the present embodiment is performed by the difference between the synthetic inertance L1 on the inlet flow path 81 side and the synthetic inertance L2 on the outlet flow path 82 side.

First, inertance will be described.
The inertance L is represented by L = ρ × h / S, where ρ is the density of the liquid, 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 liquid flowing in 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.

The combined inertance L1 on the inlet channel 81 side is calculated in the range of the inlet channel 81. The synthetic inertance L2 on the outlet channel 82 side is calculated in the range of the outlet channel 82.
In addition, the thickness of the tube wall of the connection flow path tube 90 has sufficient rigidity for the pressure propagation of the liquid.

  In this embodiment, the flow path length and cross-sectional area of the inlet flow path 81 and the outlet flow path 82 are set so that the combined inertance L1 on the inlet flow path 81 side is larger than the synthetic inertance L2 on the outlet flow path 82 side. Set the channel length and cross-sectional area.

Next, the fluid ejection operation will be described.
Liquid is always supplied to the inlet channel 81 by the pump 10 at a constant pressure (steady flow rate). As a result, when the piezoelectric element 30 does not operate, the liquid flows into the fluid chamber 80 due to the difference between the discharge force of the pump 10 and the channel resistance on the entire inlet channel 81 side.

  Here, if a drive signal is input to the piezoelectric element 30 and the piezoelectric element 30 suddenly expands in the normal direction of the surface of the diaphragm 40 on the fluid chamber 80 side, the diaphragm 40 is pressed by the expanded piezoelectric element 30, and the diaphragm 40 is deformed in the direction of reducing the volume of the fluid chamber 80. If the combined inertances L1 and L2 on the inlet channel 81 side and the outlet channel 82 side have a sufficient size, the pressure in the fluid chamber 80 rapidly increases and reaches several tens of atmospheres.

  Since this pressure is much larger than the pressure by the pump 10 applied to the inlet channel 81, the inflow of liquid from the inlet channel 81 into the fluid chamber 80 is reduced by the pressure, and the pressure from the outlet channel 82 is reduced. Outflow increases.

  However, the combined inertance L1 on the inlet flow path 81 side is larger than the combined inertance L2 on the outlet flow path 82 side, and is discharged from the outlet flow path 82 more than the reduction amount of the flow rate flowing into the fluid chamber 80 from the inlet flow path 81. Since the increased amount of liquid to be applied is larger, pulsed liquid discharge, that is, pulsating flow is generated in the connection flow path 91. The pressure fluctuation at the time of discharge propagates in the connection flow channel pipe 90 (connection flow channel 91), and the liquid is ejected from the fluid ejection opening 96 of the nozzle 95 at the tip.

  Here, since the flow path diameter of the fluid ejection opening 96 is smaller than the flow path diameter of the outlet flow path 82, the liquid has a higher pressure and is ejected at high speed as pulsed droplets.

  On the other hand, the inside of the fluid chamber 80 is in a vacuum state immediately after the pressure rises due to the interaction between the decrease in the amount of liquid inflow from the inlet channel 81 and the increase in the outflow of liquid from the outlet channel 82. Then, when the piezoelectric element 30 is restored to its original shape, the liquid in the inlet channel 81 flows before the operation of the piezoelectric element 30 (before expansion) after a certain time has elapsed due to both the pressure of the pump 10 and the vacuum state in the fluid chamber 80. ) Returns to the fluid chamber 80 at the same speed.

  If the piezoelectric element 30 is expanded after the flow of the liquid in the inlet channel 81 is restored, pulsed droplets are continuously ejected from the fluid ejection opening 96.

Subsequently, a control method of the fluid ejecting apparatus 1 according to the present embodiment will be described. First, the configuration of the control system of the fluid ejection device 1 will be described with reference to the drawings.
FIG. 4 is a configuration explanatory diagram showing a schematic configuration of a control system according to the present embodiment. The control system includes a drive control unit 15 that controls driving of the pump 10 and the pulsating flow generation unit 20 (specifically, the piezoelectric element 30), and a pulsating flow generation unit activation switch that switches start and stop of expansion and contraction of the piezoelectric element 30. 25, a pulsation amount changeover switch 27 that switches the expansion amount of the piezoelectric element 30, and a pulsation frequency changeover switch 28 that switches a repetition frequency of expansion and contraction of the piezoelectric element 30.

  The drive control unit 15 includes a pump drive circuit 153, a piezoelectric element drive circuit 154, and a control circuit 151 that controls both circuits. The drive control unit 15 further includes an LUT (Look Up Table) 152. The LUT 152 stores an increased flow rate of the pump 10 at the time of starting the pulsating flow generation unit 20 and an increased flow specified time (hereinafter, simply referred to as a specified time). Although not shown in FIG. 4, the LUT 152 is stored as data in a memory (storage means) such as a RAM (Random Access Memory) and a ROM (Read Only Memory).

  The LUT 152 is stored in a one-dimensional array in which information on an increased flow rate and an increased flow rate specified time corresponding to a specified steady flow rate value set in the pump 10 is stored. Therefore, the information on the increased flow rate and the increased flow specified time stored in the LUT 152 is read based on the specified steady flow value set in the pump 10. The designated steady flow set in the pump 10 is calculated by the drive control unit 15 from the information on the volume change amount of the volume change and the information on the repetition frequency of the volume change. Information on the volume change amount of the volume change and information on the repetition frequency of the volume change are obtained by the pulsation amount changeover switch 27 and the pulsation frequency changeover switch 28.

An example of a steady flow rate calculation method will be briefly described.
First, the volume change amount of the fluid chamber due to one extension of the piezoelectric element 30 is obtained from the product of the extension amount of the piezoelectric element 30 and the known sectional area of the fluid chamber 80. Then, the predicted flow rate discharged from the fluid chamber 80 is obtained from the product of the obtained volume change amount and the repetition frequency of expansion and contraction of the piezoelectric element 30 (that is, the repetition frequency of volume change). At this time, the specified steady flow set in the pump 10 needs to be at least equal to or higher than the flow discharged from the fluid chamber 80 so that the liquid to be ejected is not insufficient. Therefore, the specified steady flow rate set in the pump 10 is calculated by multiplying the predicted flow rate discharged from the fluid chamber 80 by a factor of 1 or more, or by increasing the flow rate.

  In addition, since it is only necessary to finally determine the increase flow rate and the increase flow specified time, it is not always necessary to calculate the specified steady flow rate. For example, if the information on the increase flow rate and the increase flow specified time stored in the LUT 152 is stored as a two-dimensional array based on the values of the pulsation amount changeover switch 27 and the pulsation frequency changeover switch 28, the pulsation amount changeover The increased flow rate and the increased flow rate designated time can be determined by the switch 27 and the pulsation frequency changeover switch 28.

  In addition, when the flow path such as the size of the nozzle 95 or the length of the tube 4 changes, or when the viscosity or specific gravity of the liquid changes due to the change of the liquid, it increases due to the pressure loss due to the flow resistance or the elastic element in the flow path. Flow rate and increase flow specified time are different. Therefore, information on the flow path and the liquid is input to the control circuit 151 by the flow path liquid information input means (input means) 26. As the channel liquid information input means 26, a keyboard or an input switch can be used.

The flow path liquid information will be briefly described.
The flow path liquid information is information for determining the pressure state in the flow path that varies depending on the flow rate. Therefore, various information such as the channel length, the channel cross-sectional area, the viscosity and specific gravity of the liquid, and the elastic compliance of the pressure fluctuation absorber 5 are required. Further, even if all of the information such as the size of the nozzle 95 and the length of the tube 4 are directly input, it is not easy to calculate the increased flow rate and the increased flow designated time. Therefore, numbers are assigned to nozzles 95, tubes 4, pressure fluctuation absorbers 5 and the like that may be used in advance, and an increase flow rate and an increase flow specified time are determined by an experiment of a combination thereof, and a plurality of LUTs 152 are prepared. Keep it. And it selects from several LUT152 according to the combination of the number of flow-path liquid information.

Note that if the flow channel or liquid to be used is uniquely determined or there is no significant change in the flow channel or liquid, the specific LUT 152 may be automatically selected without inputting the flow channel liquid information.
Further, without preparing a plurality of LUTs 152, the information on the increased flow rate and the increased flow rate specified time stored in the LUT 152 may be stored as an n-dimensional array based on the flow channel liquid information and the steady flow rate.

  From the above, when the fluid ejecting apparatus 1 is driven, first, the flow channel liquid information is input from the flow channel liquid information input means 26 to the control circuit 151. Then, the drive control unit 15 calculates a specified steady flow rate set in the pump 10 from the pulsation amount changeover switch 27 and the pulsation frequency changeover switch 28. Then, the information on the increased flow rate and the increased flow rate specified time stored in the LUT 152 is read based on the specified steady flow rate value set in the pump 10.

  When the pulsating flow generation unit activation switch 25 is operated to activate the pulsating flow generation unit 20, the pump 10 is driven based on the increased flow rate read from the LUT 152 and the specified time for flow with the increased flow rate.

(Control method of fluid ejection device)
Subsequently, a control method of the fluid ejecting apparatus 1 will be described. First, a case where the control according to the present embodiment is not performed will be described.
FIG. 5 is a graph schematically showing an injection flow rate when the control according to the present embodiment is not performed. The pump 10 stably supplies a liquid having a steady flow rate q <b> 1 designated via the pressure fluctuation absorption unit 5.

  However, when the piezoelectric element 30 is driven and the liquid is ejected in a pulse shape, the internal pressure of the pulsating flow generation unit 20 increases and the flow path resistance of the flow path increases. At this time, the fluid pressure in the pressure fluctuation absorber 5 also increases, and the pressure fluctuation absorber 5 that absorbs the pressure fluctuation due to the volume change is expanded. As a result, the amount of liquid supplied to the pulsating flow generation unit 20 temporarily decreases to the flow rate q2, and it takes time until a stable steady flow rate is obtained. For example, when the pulsating flow generation unit 20 is activated at time t1, desired stable fluid ejection cannot be performed due to a decrease in the supply flow rate during the period from activation to time t2.

In addition, when such a decrease in the supply flow rate to the pulsating flow generation unit 20 occurs, the fluid injection amount decreases during the period from time t1 to time t2, and when the fluid injection amount decreases extremely, liquid is supplied to the fluid chamber 80. In some cases, the piezoelectric element 30 may be idly driven.
Therefore, the supply flow rate from the pump 10 is controlled in order to ensure a desired injection flow rate (steady injection amount) immediately after the activation of the pulsating flow generation unit 20.

  FIG. 6 is a flowchart illustrating a method for controlling the fluid ejection device 1 according to the present embodiment. Description will be made along the flow shown in FIG. Reference is also made to FIGS.

  The control flow shown in FIG. 6 starts from the state where the pump 10 is driven and the liquid is supplied to the pulsating flow generation unit 20 at a steady flow rate, and the pulsating flow generation unit 20 is activated to drive the pulsating flow generation unit 20. This shows the flow during the stop of the incision surgery and the like.

  First, before driving the pulsating flow generation unit 20, the flow channel liquid information input means 26 inputs flow channel liquid information to the control circuit 151 (step 10, hereinafter, step is referred to as ST). As the flow path liquid information, the code number of the pressure fluctuation absorption unit 5, the code number of the tube 4, the code number of the pulsating flow generation unit 20, and the code number of the nozzle 95 are input.

  Subsequently, by operating the pulsation amount changeover switch 27 and the pulsation frequency changeover switch 28, the expansion amount of the piezoelectric element 30 (that is, equivalent to the volume change amount) and the repetition frequency of expansion and contraction of the piezoelectric element 30 (that is, the repetition frequency of volume change). (ST15). Regarding the extension amount of the piezoelectric element 30, a driving voltage or the like may be used if the piezoelectric constant is already known. Therefore, it is assumed that 100 V and 300 Hz are selected. A specified flow rate (steady flow rate) is calculated from the expansion amount of the piezoelectric element 30 and the repetition frequency of expansion and contraction. It is assumed that 100 ml / h is calculated. Then, the LUT 152 is selected based on the input flow channel liquid information, and the specified flow rate (steady flow rate) is referred to, the LUT 152 is referred to, and the flow rate is increased to 30 ml / h for a specified time 5 s (5 seconds). ) Is determined.

  Subsequently, driving of the pump 10 is started at the calculated specified steady flow rate (ST20). Then, the pulsating flow generation unit activation switch 25 is operated to activate the pulsating flow generation unit 20 and start driving (ST30). At this time, a read signal is sent from the control circuit 151 to the LUT 152, and the control conditions (increase flow rate 30 ml / h, designated time 5 s) are read.

  Almost simultaneously with the start of driving of the pulsating flow generation unit 20, the liquid supply amount from the pump 10 is increased based on the control conditions (ST40). Since the increased flow rate is 30 ml / h, the supply flow rate from the pump 10 is 130 ml / h obtained by adding the increased flow rate 30 ml / h to the specified steady flow rate 100 ml / h.

  Here, the control circuit 151 measures the elapse of the time (designated time) supplied at the increased flow rate and determines whether the designated time (5 seconds) has elapsed as designated (ST50). While the specified time does not reach 5 seconds (NO), the supply is continued at an increased flow rate. After the specified time has elapsed (YES), the liquid supply amount from the pump 10 is reduced to a steady flow rate (ST60) and the state is continued (ST70). The period of ST70 is a period of use of the pulsating flow generation unit 20 due to surgery or the like.

  When the operation or the like is paused or ended, the pulsating flow generation unit activation switch 25 is operated to stop driving the pulsating flow generation unit 20 (ST80). Therefore, the pulsating flow generation unit activation switch 25 is a two-state changeover switch that can be activated and stopped.

  Then, it is determined whether the fluid ejecting apparatus 1 is to be stopped or temporarily stopped (ST90). If the driving is stopped, the pulsation frequency changeover switch 28 is operated to stop driving the pump 10 (ST100).

  Further, when the suspension is made at ST90, the driving of the pump 10 is maintained without operating the pulsation frequency changeover switch 28. When driving the pulsating flow generation unit 20 again, the pulsating flow generation unit activation switch 25 is operated to activate the pulsating flow generation unit 20 (ST30). In this case, the pulsating flow generator drive stop (ST80) period is a temporary suspension period.

  In addition, when it becomes necessary to switch the pulsation amount changeover switch 27 and the pulsation frequency changeover switch 28 when restarting after the temporary suspension period, the pulsation amount changeover switch 27 and the pulsation frequency changeover switch 28 are operated, It is also possible to recalculate the specified flow rate (steady flow rate) (return to ST15). And when driving the pulsating flow generation part 20 continuously, the drive of the pump 10 and the pulsating flow generation part 20 is continued as it is.

Next, the fluid ejection amount by the control method as described above will be described.
FIG. 7 is a graph schematically showing an injection flow rate when the control according to the present embodiment is performed. In the present embodiment, almost simultaneously with the activation of the pulsating flow generation unit 20 (A in the figure), the liquid supply amount from the pump 10 is increased, and the supply amount is decreased when the specified increased flow rate and the specified time are reached (in the figure). B) Return to the steady flow rate q1 (C in the figure).

  Therefore, the decrease q3 in the liquid injection flow rate immediately after starting the pulsating flow generation unit 20 is very small compared to the decrease q2 in the injection amount when the control according to the present embodiment is not performed, and the pulsating flow generation unit 20 is started. Then, the time until the steady injection amount can be obtained can be shortened as compared with the conventional case.

  According to the fluid ejecting apparatus 1 and the control method of the fluid ejecting apparatus 1 described above, when the pulsating flow generating unit 20 is activated, the amount of decrease due to expansion of the pressure fluctuation absorbing unit 5 is compensated. By increasing the liquid supply amount from the pump 10 beyond the steady flow rate, the liquid can be stably jetted at high speed immediately after the pulsating flow generation unit 20 is started.

  Further, when the piezoelectric element 30 is driven in a state where the supply flow rate to the pulsating flow generation unit 20 (specifically, the fluid chamber 80) is reduced or not, in addition to the heat generated by the expansion and contraction of the piezoelectric element 30, the inside of the fluid chamber 80 There is a possibility that the heat generation due to the heat insulation effect and the temperature of the piezoelectric element 30 increase due to an insufficient amount of the liquid that also acts as a refrigerant. According to the present embodiment, since the supply flow rate is sufficient, there is an effect that the deterioration of the piezoelectric element 30 due to the temperature rise can be prevented.

  In addition, the expansion amount of the piezoelectric element 30 (that corresponds to the volume change amount) that affects the pressure increase when the pulsating flow generation unit 20 is started up, and the repetition frequency of expansion and contraction of the piezoelectric element 30 (that is, the repetition frequency of volume change). ), The pump 10 is driven based on the specified time and the increased flow rate determined from the above, so that the supply flow rate can be increased accurately and the liquid can be stably ejected immediately after the start of the pulsating flow generation unit 20. . Further, it is not necessary for the operator (operator) to calculate and input the steady flow rate, the designated time and the increased flow rate every time, and the operability can be improved.

FIG. 8 is a flowchart illustrating a method for controlling the fluid ejection device 1 according to a modification of the present embodiment.
In the present embodiment, the pulsating flow generation unit 20 is started from the state in which the liquid is supplied to the pulsating flow generation unit 20 at a steady flow rate, but the pump 10 is similar to the control flow shown in FIG. And the pulsating flow generation unit 20 may be activated simultaneously (ST35). However, in this case, since the pressure in the flow path is not high until immediately before starting, it is difficult to achieve a more stable steady flow rate until the pressure in the pressure fluctuation absorbing unit 5 increases. Therefore, since the designated time and the increased flow rate are relatively large, an LUT 152 corresponding to this is prepared. As a result, while the liquid is not ejected in a pulsed manner, it is possible to stop ejecting excess liquid, and at the same time, the liquid can be stably ejected in a pulsed manner at a high speed immediately after the pulsating flow generation unit 20 is activated. it can. The pump 10 and the pulsating flow generation unit 20 may be stopped simultaneously (ST85).

(Embodiment 2)
Next, the fluid ejecting apparatus according to the second embodiment will be described with reference to the drawings. In contrast to the above-described embodiment 1 in which the surgeon grasps and operates the pulsating flow generation unit 20, the second embodiment attaches the pulsating flow generation unit to the distal end of the tube. It has a feature that it is a structure that can be inserted into a thin tube tissue such as. In the second embodiment, common parts with the first embodiment are denoted by the same reference numerals, and different points will be mainly described.

  FIG. 9 is a side partial sectional view showing a cut surface obtained by cutting the pulsating flow generation unit according to the present embodiment in a direction perpendicular to the diaphragm. The pulsating flow generation unit 120 is configured in a cylindrical shape with a substantially circular cross section in a state where the opposing surfaces of the upper case 170 and the lower case 150 are joined. A concave portion is formed in a surface facing the upper case 170 of the lower case 150, and a fluid chamber 180 is configured by the concave portion and the diaphragm 140 closely fixed to the surface facing the lower case 150 of the upper case 170. .

The lower case 150 is formed with an inlet channel 181 and an outlet channel 182 communicating with the fluid chamber 180, and the piezoelectric element 130 is fixed to the surface of the diaphragm 140 opposite to the fluid chamber 180. Note that the tip of the outlet channel 182 is a fluid ejection opening 97.
As is clear from FIG. 9, the pulsating flow generation unit 120 according to the present embodiment has an inlet channel 181, a fluid chamber 180, and an outlet channel 182 formed in a straight line. By adopting such a configuration, it is possible to reduce the number of wall portions with which the liquid collides, and thus it is possible to reduce bubbles that stay in the wall portion with which the liquid collides. As a result, it is possible to prevent the pressure in the fluid chamber 180 from being lowered due to the influence of the accumulated bubbles, and to stably generate a pulsating flow having a sufficient excision ability.

  In FIG. 9, the diaphragm 140 is arranged in parallel with the bottom surface of the fluid chamber 180 (surface formed by the lower case 150). In other words, it can be said that the diaphragm 140 is arranged in parallel to the liquid flowing direction. By adopting such a configuration, the outer diameter of the pulsating flow generation unit 120 can be made substantially equal to the outer diameter of the tube 6, and the pulsating flow generation unit 120 is inserted into a tubule tissue such as a blood vessel as will be described later. It becomes possible.

  Further, by arranging the diaphragm 140 in parallel with the bottom surface of the fluid chamber 180, the area in which the diaphragm 140 forms the fluid chamber 180 can be increased. Thereby, the amount (= volume change amount of the fluid chamber 180) for reducing the volume of the fluid chamber 180 due to the deformation of the diaphragm 140 can be increased. For example, when the diaphragm 140 is disposed perpendicular to the bottom surface of the fluid chamber 180, the area in which the diaphragm 140 forms the fluid chamber 180 is limited to the outer diameter of the pulsating flow generation unit 120, and the volume change amount of the fluid chamber 180 due to the deformation of the diaphragm 140. Cannot be increased.

  As a result, it becomes difficult to generate a pulsating flow having a sufficient excision ability. In that respect, in the configuration of the present embodiment, the volume change amount of the fluid chamber can be increased by the deformation of the diaphragm 140 without being limited to the outer diameter of the pulsating flow generation unit 120, so that the sufficient excision ability is provided. A pulsating flow can be generated, which is preferable.

  The pulsating flow generation unit 120 configured in this way is connected to the tube 6. Liquid that is pumped from the pump 10 passes through the tube 6 via the pressure fluctuation absorbing portion 5. That is, between the pump 10 and the pulsating flow generation unit 20, a pressure fluctuation absorption unit 5 that absorbs pressure fluctuations by volume change is provided. Here, the pulsating flow generation unit 120 is a device suitable for being inserted into a tubule tissue such as a blood vessel and removing deposits and the like in the tubule tissue, and has an outer diameter of about 2 mm to 5 mm. Therefore, the outer diameter of the tube 6 is substantially equal to the outer diameter of the pulsating flow generation unit 120. However, the tube 6 can be considered as a catheter.

Even with the thin tubular pulsating flow generation section 120 configured as described above, the same effects as those of the first embodiment described above can be obtained, and further, the thin tubular pulsating flow generation section 120 can be inserted into the thin tube tissue and attached to the inner wall of the thin tube tissue. It is effective as a surgical instrument suitable for removal.
Furthermore, it can be used for cleaning the inside of the tube of the thin tube structure.

  In the present embodiment, the pulsating flow generation unit activation switch 25 is disposed in the drive control unit 15.

  The drive control of the fluid ejection device in the present embodiment can be performed by the same control method as in the first embodiment.

  In the first and second embodiments described above, the pulsating flow is generated by pressing the diaphragms 40 and 140 with the piezoelectric elements 30 and 130. However, the present invention is not limited thereto, and the pulsating flow is generated. Other forms may be used as long as they are present. For example, the volume of the fluid chamber may be reduced by driving a piston (plunger) using a piezoelectric element to generate a pulsating flow. Alternatively, the liquid in the fluid chamber may be formed into a bubble (bubble) by laser induction, and a pulsating flow may be generated by ejecting the bubble.

  In the first embodiment described above, the LUT 152 is referred to determine the control condition (the specified flow rate for increasing flow rate and increased flow rate) corresponding to the input flow channel liquid information. When the control condition corresponding to the flow path liquid information does not exist in the LUT 152, the control condition that seems to be optimal for the input flow path liquid information is determined from the plurality of flow path liquid information and control conditions stored as the LUT 152. You may make it obtain | require by a well-known interpolation calculation. As a result, even if the control condition corresponding to the input flow channel liquid information does not exist in the LUT 152, it is possible to derive a control condition that seems appropriate.

  In the first embodiment described above, the flow channel liquid information is input by the flow channel liquid information input unit 26. However, the present invention is not limited to this, and an RF-ID or barcode attached to a part of the apparatus. May be configured to input flow channel liquid information to the control circuit 151. Thereby, the effort which a user inputs flow-path liquid information can be reduced.

  DESCRIPTION OF SYMBOLS 1 ... Fluid injection apparatus 2 ... Liquid supply container 4, 6 ... Liquid supply tube 5 ... Pressure fluctuation absorption part 10 ... Pump as fluid supply part 15 ... Drive control part 20 ... Pulse flow generation part 25 ... Pulse flow generation part starting switch 26 ... Flow path liquid information input means (input means) 27 ... Pulsation amount changeover switch 28 ... Pulsation frequency changeover switch 30 ... Piezoelectric element as volume changing means 40 ... Diaphragm as volume changing means 50 ... Lower case 51 ... Wall surface 52 ... Air bag 60 ... Bottom plate 70 ... Upper case 80 ... Fluid chamber 81 ... Inlet channel 82 ... Outlet channel 90 ... Connection channel tube 91 ... Connection channel 95 ... Nozzle 96, 97 ... Fluid injection opening 120 ... Generation of pulsating flow Part 130 ... Piezoelectric element 140 ... Diaphragm 150 ... Lower case 151 ... Control circuit 152 ... LUT 153 ... Pump drive circuit 154 ... Piezoelectric element drive circuit 170 ... upper case 180 ... fluid chamber 181 ... inlet channel 182 ... outlet channel

Claims (4)

A pulsating flow generating section for injecting liquid in pulses;
A fluid supply unit that pumps liquid by periodic driving and supplies the liquid to the pulsating flow generation unit;
A pressure fluctuation absorbing section that absorbs pressure fluctuation by a volume change disposed between the pulsating flow generation section and the fluid supply section;
A drive control unit that performs drive control of the pulsating flow generation unit and the fluid supply unit based on a specified flow rate;
Have
When the designated flow rate is the second flow rate, and the flow rate obtained by adding the increased flow rate to the second flow rate is the first flow rate,
The drive control unit activates the pulsating flow generation unit and supplies the first flow rate of liquid from the fluid supply unit for a predetermined time. After the predetermined time has elapsed, the drive control unit supplies the second flow rate of liquid from the fluid supply unit. A fluid ejecting apparatus. The fluid ejection device according to claim 1,
The fluid ejection device, wherein the drive control unit also activates the fluid supply unit when the pulsating flow generation unit is activated. The fluid ejection device according to claim 1 or 2,
A fluid chamber for injecting liquid into the pulsating flow generating section by changing the volume;
Input means for inputting information on the volume change amount of the volume change and information on the repetition frequency of the volume change;
Have
The drive control unit determines one of the first flow rate, a predetermined time for supplying the liquid at the first flow rate, and the second flow rate from the information on the volume change amount and the volume change repetition frequency. A fluid ejecting apparatus. A pulsating flow generating unit that ejects the liquid in pulses; a fluid supply unit that pumps liquid by periodic driving and supplies the liquid to the pulsating flow generating unit; and the pulsating flow generating unit and the fluid supply unit, A pressure fluctuation absorption unit that absorbs pressure fluctuations by a volume change disposed between and a drive control unit that performs drive control of the pulsating flow generation unit and the fluid supply unit based on a specified flow rate. A control method for a fluid ejection device,
When the designated flow rate is the second flow rate, and the flow rate obtained by adding the increased flow rate to the second flow rate is the first flow rate,
The drive control unit activates the pulsating flow generation unit and supplies the first flow rate of liquid from the fluid supply unit for a predetermined time;
The drive control unit supplying the second flow rate of liquid from the fluid supply unit after elapse of the predetermined time;
A control method of a fluid ejecting apparatus comprising: