JP2013215548A - Liquid circulating apparatus and medical apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology that can stably secure circulation efficiency in a liquid circulating apparatus.SOLUTION: A liquid circulating apparatus for circulating liquid in non-contact with the atmosphere includes: a pump chamber whose volume is changed by a volume changing means; a liquid resistance element for restraining or blocking the flow of liquid toward an inlet passage from an inlet passage pump chamber which is an inflow passage of liquid to the pump chamber; an outlet passage which is an outflow port of liquid from the pump chamber; a circulating passage with a length L for circulating liquid from the outlet passage to the inlet passage; and a pressure regulating mechanism for storing the liquid of volume Vb during the non-operation of the volume changing means and supplying the stored liquid as a part of the circulating liquid during the operation of the volume changing means. When the compliance of the circulating passage is set as Cs, and the pressure of the liquid in the circulating passage in a position of length x from the outlet passage during the operation of the volume changing means is set as P(x), the volume Vb satisfies a predetermined relationship.

Description

  The present invention relates to a liquid circulation device.

  Conventionally, a technique using a liquid circulation device is known as a technique for adjusting the temperature of an object (for example, Patent Document 1). In this technique, a circulation channel through which a liquid circulates is brought into contact with an object whose temperature is to be adjusted (hereinafter also referred to as a temperature adjustment object), and the temperature of the temperature adjustment object is adjusted according to the temperature of the circulating liquid. However, since the conventional liquid circulation device is not configured in consideration of the pressure inside the circulation flow channel during operation, depending on the operating conditions, for example, the flow channel cross-sectional area becomes small and the liquid circulation efficiency decreases. The problem was pointed out.

JP-A-8-242463

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to stably ensure the circulation efficiency.

In order to solve at least a part of the problems described above, the present invention can take the following forms or application examples.
[Application Example 1]
Application example 1 is a liquid circulation device that circulates liquid in a non-contact manner with the atmosphere, a pump chamber whose volume is changed by volume changing means, an inlet flow channel that is an inflow path of liquid to the pump chamber, A liquid resistance element that suppresses or inhibits the flow of the liquid from the pump chamber toward the inlet channel, an outlet channel that is an outlet of the liquid from the pump chamber, and the outlet channel to the inlet channel. The circulation channel of the length L through which the liquid circulates and the volume changing means when the volume changing means is not in operation are accommodated, and the volume changing means is circulated when the volume changing means is in operation. A pressure adjusting mechanism that supplies the liquid as a part of the liquid, the compliance of the circulation channel is Cs, and the volume changing means is operated in the circulation channel at a position of length x from the outlet channel. Of the above The pressure of the body case of the P (x), the volume Vb is directed to subject matter that satisfies the relation of equation (3).

  According to this liquid circulation device, the pressure adjusting mechanism supplies the accommodated volume Vb as part of the liquid circulating in the circulation channel when the volume changing means is operated. Therefore, it is possible to suppress a significant decrease in the pressure inside the circulation channel during the operation of the volume changing means. Further, when γ is set to 1 or more and the liquid of the volume Vb is accommodated in the pressure adjusting mechanism, the value of the pressure P (x) inside the circulation channel during the operation of the volume changing means is the volume changing means. It is possible to suppress the pressure from being equal to or lower than the internal pressure of the circulation flow path when not operating. Therefore, the circulation efficiency can be secured stably.

[Application Example 2]
In the liquid circulation device according to Application Example 1, when the pressure of the liquid flowing out from the outlet flow path to the circulation flow path is Ps, the volume Vb may satisfy the relationship of Expression (4). .

  According to this liquid circulation device, the pressure adjusting mechanism supplies the accommodated volume Vb as part of the liquid circulating in the circulation channel when the volume changing means is operated. Therefore, it is possible to suppress a significant decrease in the pressure inside the circulation channel during the operation of the volume changing means. In particular, if γ is set to 1 or more and a volume Vb of liquid is accommodated in the pressure adjusting mechanism, the pressure inside the circulation channel when the volume changing unit is in operation is changed to the inside pressure of the circulation channel when the volume changing unit is not operating. It can suppress more reliably that it becomes below the pressure of this.

[Application Example 3]
In the liquid circulation device according to Application Example 1 or Application Example 2, the pressure adjustment mechanism includes a liquid storage chamber that stores the liquid used for the supply, and according to the amount of the liquid stored in the interior. It may be deformable.
According to this liquid circulation device, the pressure adjusting mechanism uses a liquid storage chamber that can be deformed in accordance with the amount of liquid stored inside, so that even if the amount of liquid stored inside changes, The pressure can be kept within a predetermined range.

[Application Example 4]
In the liquid circulation device according to Application Example 3, the liquid storage chamber may be a pack formed by sealing a film in a bag shape.
According to this liquid circulation device, since the pack is used as the pressure adjusting mechanism, it is possible to make it possible to supply liquid easily.

[Application Example 5]
In the liquid circulation device according to application example 4, the liquid storage chamber may be detachable from the liquid circulation device.
According to this liquid circulation device, since the liquid storage chamber can be detached, only the liquid storage chamber can be replaced.

[Application Example 6]
In the liquid circulation device according to any one of Application Example 1 to Application Example 5, the pressure adjustment mechanism may include a branch flow path branched from the circulation flow path.
According to this liquid circulation device, since the branch flow path is used as the pressure adjusting mechanism, it is possible to easily supply the liquid.

[Application Example 7]
In the liquid circulation device according to Application Example 6, the accommodated liquid is sealed inside the branch flow path, and a pressure difference between the pressure of the liquid in the branch flow path and atmospheric pressure is set. The sealing material which moves according to this can be arranged.
According to this liquid circulation device, since the sealing material is disposed in the branch channel, it is possible to prevent the liquid from flowing out from the branch channel. Since the sealing material moves according to the pressure difference between the pressure of the liquid in the branch flow path and the atmospheric pressure, the internal pressure can be maintained within a predetermined range.

[Application Example 8]
In the liquid circulation device according to Application Example 7, the liquid is a first liquid, and the first liquid and the sealing material are disposed between the first liquid and the sealing material in the branch channel. A second liquid that can be phase-separated from the liquid is sealed, and the heat of vaporization of the second liquid may be greater than the heat of vaporization of the first liquid.
According to this liquid circulation device, the first liquid can be prevented from being vaporized from the branch flow path.

[Application Example 9]
In the liquid circulating apparatus according to any one of Application Examples 1 to 8, the volume changing unit may use an operating element that operates according to a change in voltage.
According to this liquid ejecting apparatus, the volume change of the pump chamber can be electrically controlled.

[Application Example 10]
Moreover, it is good also as a medical device using the liquid circulation apparatus as described in any one of the application examples 1 to 9.
According to this medical device, a liquid circulation device that ensures stable circulation efficiency can be used.

[Application Example 11]
Further, a liquid ejecting apparatus using the liquid circulation apparatus according to any one of Application Examples 1 to 9 may be used.
According to this liquid ejecting apparatus, it is possible to use a liquid circulating apparatus that ensures stable circulation efficiency.

  Note that the present invention can be realized in various modes. For example, the present invention can be realized in the form of a liquid circulation method and apparatus, a liquid circulation system, a temperature adjustment device, and the like.

It is explanatory drawing which shows schematic structure of a liquid injection system. It is a schematic diagram which shows the structure of a liquid circulation apparatus roughly. It is explanatory drawing which shows the flow of the liquid in the inside of a circulation pump. It is explanatory drawing which shows the structure of a film pack. It is explanatory drawing explaining the liquid flow path by which the internal pressure was maintained appropriately. It is explanatory drawing explaining the structure of a branch flow path. It is explanatory drawing explaining the modification 6. FIG.

A. First embodiment:
(A1) System configuration:
Embodiments of the present invention will be described based on examples. FIG. 1 is an explanatory diagram showing a schematic configuration of a liquid ejecting system 10 as an embodiment of the present invention. The liquid ejection system 10 includes a liquid ejection device 20 and a liquid circulation device 100 that cools the liquid ejection device 20. The liquid ejecting apparatus 20 is a water jet knife that ejects a jet water flow onto a living tissue such as skin and peels and incises the living tissue by the impact energy. In particular, the liquid ejecting apparatus 20 of the present embodiment is a water jet pulse knife that ejects a jet water flow intermittently.

  The liquid ejecting apparatus 20 includes a pulsation generating unit 30 that ejects a jet water flow, a liquid container 40 that stores water, a supply pump 42 that sucks up water that is stored in the liquid container 40 and supplies the water to the pulsation generating unit 30. A connection tube 44 that connects the liquid container 40 and the supply pump 42 and a connection tube 46 that connects the supply pump 42 and the pulsation generator 30 are provided.

  The pulsation generating unit 30 communicates with the liquid chamber 32, a liquid chamber 32 that temporarily stores water supplied from the connection tube 46, a piezoelectric actuator 34 that pulsates the water stored in the liquid chamber 32, and the liquid chamber 32. A liquid jet pipe 36 through which water pulsated by the piezoelectric actuator 34 passes, a lower case 38 that accommodates the piezoelectric actuator 34 therein, a liquid chamber 32, and an upper case 39 connected to the lower case 38. And.

  The piezoelectric actuator 34 is a laminated piezoelectric element, and changes the volume of the liquid chamber 32 by deforming the diaphragm using the piezoelectric effect of the piezoelectric element (piezo element). When the volume of the liquid chamber 32 is reduced, the water stored in the liquid chamber 32 passes through the liquid jet pipe 36 and is jetted to the outside as a jet water flow. As another means for changing the volume of the liquid chamber 32, the volume of the liquid chamber 32 may be changed by driving the piston and displacing the piston.

  The liquid circulation device 100 is a device that cools the piezoelectric actuator 34 of the liquid ejecting apparatus 20, and includes a circulation pump 110 and a liquid channel 190 that is connected to the circulation pump 110 at both ends and is a circulation channel. The liquid channel 190 is a tube having pressure resistance and flexibility. As the tube, for example, a medical tube or a general industrial tube made of thermoplastic resin such as PTFE or other fluororesin, polyimide resin, PVC resin, or silicone rubber can be applied. There is no particular limitation. It is wound around the piezoelectric actuator 34. For this reason, the heat generated in the piezoelectric actuator 34 is transferred to the liquid circulating in the liquid flow path 190 (circulating liquid), and the piezoelectric actuator 34 is cooled. The circulating liquid whose temperature has risen is cooled by air cooling while circulating in the liquid channel 190. In addition, the circulating liquid may be cooled separately using a radiator. In this embodiment, the circulating liquid is a liquid in consideration of heat exchange efficiency. In the liquid circulation device 100, various liquids such as water and oil can be adopted as the liquid. For example, if silicone oil having a specific viscosity with low volatility is employed in the liquid circulation device 100, the liquid circulation device 100 can be provided, which makes it difficult for the circulating liquid to evaporate and can be used for a long time.

  FIG. 2 is a schematic diagram schematically showing a cross-sectional configuration of the liquid circulation device 100. In the present embodiment, in the liquid circulation device 100, a closed circulation path is configured by the circulation pump 110 and the liquid flow path 190. The closed circulation path means a circulation path having no portion where the circulating liquid is in contact with the outside (atmosphere). By adopting a closed circulation channel, it is possible to prevent bubbles and other foreign matters from entering the circulating liquid. Further, by preventing the circulating liquid itself from volatilizing and reducing its amount, the flow rate of the circulating liquid can be stably secured, which contributes to maintaining stable circulation efficiency.

  The circulation pump 110 includes a laminated piezoelectric element 114, a piezoelectric element case 112 that accommodates the piezoelectric element 114 therein, and a flow path case 140 in which a flow path is formed. The bottom of the piezoelectric element 114 is fixed to the piezoelectric element case 112. A circular reinforcing plate 116 is attached to the upper end of the piezoelectric element 114, and a circular diaphragm 118 formed of a thin metal plate or the like is bonded to the upper surface of the reinforcing plate 116. The reinforcing plate 116 reinforces the strength of the diaphragm 118. The thickness of the reinforcing plate 116 is set so that the lower surface of the diaphragm 118 is in contact with the upper end surface of the piezoelectric element case 112.

  A recess 140C is formed on the lower surface side of the flow path case 140 (side facing the piezoelectric element case 112), and an annular member 120 is fitted in the recess 140C. The inner diameter of the annular member 120 is smaller than the outer diameter of the diaphragm 118. When the piezoelectric element case 112 and the flow path case 140 face each other and are fixed by screws or the like, the diaphragm 118 is sandwiched between the annular member 120 and the piezoelectric element case 112, and between the flow path case 140 and the diaphragm 118. The airtightness is secured by the annular member 120. As a result, a pump chamber 130 that is a space surrounded by the recess 140 </ b> C of the case 140, the inner peripheral surface of the annular member 120, and the diaphragm 118 is formed. The volume of the pump chamber 130 changes as the piezoelectric element 114 expands or contracts and the diaphragm 118 deforms.

  The flow path case 140 further includes a liquid chamber 146 that guides the liquid to the pump chamber 130 and a pump discharge flow path 142 that is connected to one end of the liquid flow path 190 and guides the liquid in the pump chamber 130 to the liquid flow path 190. And a pump suction flow path 144 that is connected to the other end of the liquid flow path 190 and guides the liquid supplied from the liquid flow path 190 to the liquid chamber 146.

  One end of the liquid chamber 146 opens to the upper surface side of the flow path case 140 (the side opposite to the side facing the piezoelectric element case 112), and the other end communicates with the pump chamber 130, and faces the pump chamber 130 side. Thus, the diameter is reduced (so that the cross-sectional area is reduced). A pump suction flow path 144 is connected to a portion where the diameter of the liquid chamber 146 is reduced. A check valve 148 is provided at the end of the liquid chamber 146 on the pump chamber 130 side. The check valve 148 allows the liquid to flow from the liquid chamber 146 to the pump chamber 130 and prevents the liquid from flowing back from the pump chamber 130 to the liquid chamber 146.

  The film pack 160 is airtightly connected to the opening of the liquid chamber 146 formed on the upper surface side of the flow path case 140 via the connection member 162. The film pack 160 is formed of a flexible film having gas barrier properties and heat resistance in order to prevent air bubbles from being mixed into the circulating liquid. In this embodiment, the film pack 160 can be attached to and detached from the flow path case 140, so that the exchange of the film pack, the elimination of bubbles in the film pack, and the replenishment of the liquid are easy. Depending on the circulating liquid, the film does not need to have gas barrier properties and heat resistance, and the material of the film is appropriately selected. In this embodiment, the film pack 160 is detachable from the flow path case 140, but the film pack 160 may be formed integrally with the flow path case 140.

  The liquid circulation device 100 configured as described above circulates the liquid in the liquid flow path 190 by driving the piezoelectric element 114 of the circulation pump 110. Next, details of the operation of the circulation pump 110 will be described.

(A2) Operation of circulation pump 110:
FIG. 3 is an explanatory diagram showing the flow of the liquid inside the circulation pump 110. FIG. 3A is an explanatory diagram illustrating a state where the circulation pump 110 is not operating (a state before a driving voltage is applied to the piezoelectric element 114). Hereinafter, the state where the circulation pump 110 is operating is also referred to as an operating state, and the state where the circulation pump 110 is not operating is also referred to as a stopped state. In the stopped state, the pump chamber 130 is filled with liquid. In the stopped state, the film pack 160 also contains a predetermined amount of liquid in advance. In the stop state, the pressures inside the pump chamber 130, the film pack 160, and the liquid flow path 190 are almost atmospheric pressure. The liquid stored in the film pack 160 in the stopped state (hereinafter also referred to as pressure adjusting liquid BF) is used to adjust the inside of the liquid flow path 190 to an appropriate pressure in the operating state. Details of the pressure adjusting liquid BF will be described later.

  FIG. 3B is an explanatory diagram showing a state in which a driving voltage is applied to the piezoelectric element 114. When a drive voltage is applied to the piezoelectric element 114 in a state where the pump chamber 130 is filled with liquid, the piezoelectric element 114 expands due to the applied drive voltage, and the diaphragm 118 is moved through the reinforcing plate 116 to the pump chamber 130. Push up in the direction of. When the pump chamber 130 is pushed by the diaphragm 118, the volume of the pump chamber 130 decreases and the liquid in the pump chamber 130 is pressurized. At this time, the check valve 148 is closed and the back flow of the liquid from the pump chamber 130 to the liquid chamber 146 is prevented, so that the liquid corresponding to the reduced volume of the pump chamber 130 passes through the pump discharge flow path 142. Thus, it is pumped toward the liquid channel 190.

  When the liquid is sent into the liquid flow path 190 in this way, the liquid in the liquid flow path 190 is successively pushed downstream. Further, as described above, in the liquid circulation device 100 of the present embodiment, the liquid flow path 190 and the circulation pump 110 constitute a closed system, and the liquid flow path 190 is pushed out and returned to the circulation pump 110. The liquid flows into the film pack 160 through the pump suction channel 144. Here, the film pack 160 is formed of a flexible film, and is attached in a state in which the liquid pack 160 is not completely filled with the liquid but is still inflated. Therefore, even if the liquid returned from the liquid flow path 190 flows into the film pack 160, the pressure in the film pack 160 or the liquid chamber 146 communicating with the film pack 160 increases due to the film pack 160 expanding. It is suppressed.

  FIG. 3C is an explanatory diagram showing a state in which the driving voltage applied to the piezoelectric element 114 has decreased. When the drive voltage decreases, the piezoelectric element 114 contracts and returns to its original length. Then, the volume of the pump chamber 130 increases (restores to the original volume). At this time, since the inside of the pump chamber 130 becomes negative pressure, the check valve 148 is opened, and the liquid is sucked into the pump chamber 130 from the liquid chamber 146. In addition, a negative pressure means the pressure below atmospheric pressure.

  The negative pressure in the pump chamber 130 also acts on the pump discharge channel 142. However, the flow resistance of the pump discharge flow path 142 is set to be larger than the flow resistance of the liquid chamber 146 and the check valve 148. Therefore, it is easier for the liquid to flow from the liquid chamber 146 to the pump chamber 130 than the pump discharge flow path 142. Further, the liquid chamber 146 communicates with the film pack 160, and the liquid in the film pack 160 flows into the pump chamber 130 without stagnation, so that the liquid chamber 146 is unlikely to become negative pressure.

  After the pump chamber 130 whose volume has been recovered in this way is filled with the liquid from the liquid chamber 146, when the piezoelectric element 114 expands again due to an increase in the drive voltage, as shown in FIG. The liquid pressurized inside is pumped toward the pump discharge channel 142 and the liquid channel 190. As the circulation pump 110 repeats the above-described operation, the liquid circulation device 100 circulates the liquid in the liquid flow path 190.

(A3) Structure of film pack:
FIG. 4 is an explanatory diagram showing the configuration of the film pack 160. FIG. 4A shows an exploded perspective view of the film pack 160. The film pack 160 includes a pair of flexible films 164 having gas barrier properties and heat resistance, a connecting member 162 having a communication hole 162a and detachably connecting the film pack 160 to the liquid chamber 146, and an openable opening. It is composed of an open mouth member 166 provided with a mouth. The pair of films 164 are formed in a substantially rectangular shape. The film pack 160 is formed by sandwiching the connection member 162 on one end side in the longitudinal direction of the pair of films 164, sandwiching the open port member 166 on the other end side, and airtightly bonding the periphery by thermocompression bonding or the like.

  FIG. 4B shows a film pack 160 formed by bonding a pair of films 164 together. In FIG. 4B, the seal portion bonded by thermocompression bonding or the like is shown with hatching. As shown in FIG. 4B, the film pack 160 is in a state in which the pair of films 164 are in contact with each other in a state where no liquid is accommodated therein.

  On the other hand, when the liquid flows into the film pack 160 through the communication hole 162a of the connection member 162, the film pack 160 swells as the pair of films 164 separate from each other as shown in FIG. The liquid can be accommodated. Further, when the liquid in the film pack 160 flows out through the communication hole 162a of the connecting member 162, the pair of films 164 approach each other and the film pack 160 is deflated (the volume is reduced). As described above, the film pack 160 can be easily deformed according to the amount of liquid accommodated therein, so that the pressure of the internal liquid can be maintained within a predetermined range.

  FIG. 4D illustrates the structure of the film 164 used for the film pack 160. The illustrated film 164 has a multilayer structure, and is bonded to both sides of an aluminum foil (AL) with polypropylene (PP) having excellent liquid resistance, and from above, polyethylene having excellent impact resistance on both sides. A structure in which terephthalate (PET) is bonded is adopted. Each layer is bonded by an adhesive. By providing the middle layer of the aluminum foil, the strength of the film can be enhanced and the gas barrier property can be enhanced. The film pack 160 having such a configuration has excellent heat resistance, can be handled at a high temperature (for example, 150 ° C.), has flexibility, and can be easily deformed. Since the deformation of the film pack 160 is easy, even if there is a case covering the circulation pump 110, it can be deformed in the case. As a result, since the shape of the case is not easily restricted, the case that covers the circulation pump 110 can be reduced in size. Moreover, the film pack 160 can be easily formed by thermocompression in addition to realizing weight reduction, and is economical. Furthermore, since the film pack 160 is detachable from the liquid chamber 146, it is easy to replace the film pack 160 and it is economical.

The structure of the film 164 used for the film pack 160 is not limited to the structure shown in FIG. 4 (D). For example, instead of aluminum foil as the middle layer, ethylene-vinyl alcohol copolymer resin (EVOH), Polyvinylidene chloride (PVDC) or the like may be used. Alternatively, the outer layer of polyamide (nylon) and the inner layer of polypropylene (PP) may be directly bonded with an adhesive to form a transparent film. By making a part or all of the film pack 160 transparent, it becomes possible to visually recognize the inside of the film pack 160 (the amount of liquid and the flow of liquid).

(A4) Pressure adjusting liquid BF:
Next, the pressure adjustment liquid BF will be described. The pressure adjusting liquid BF is supplied from the film pack 160 to the liquid chamber 146 as part of the circulating liquid in order to keep the inside of the liquid flow path 190 at an appropriate pressure when the circulation pump 110 changes from the stopped state to the operating state. To be supplied. In the present embodiment, “maintaining the inside of the liquid flow path 190 at an appropriate pressure” means that the pressure inside the liquid flow path 190 (hereinafter also referred to as internal pressure) is atmospheric pressure in the operating state of the circulation pump 110. Say to keep more. By maintaining the internal pressure of the liquid flow path 190 at or above atmospheric pressure by the pressure adjusting liquid BF, the liquid flow path 190 is prevented from being deformed inward by the force of atmospheric pressure and narrowing the flow path. As a result, the circulation pump 110 can avoid a decrease in the circulation efficiency of the circulating liquid by the pressure adjustment liquid BF.

  The principle that the internal pressure of the liquid flow path 190 is appropriately maintained by supplying the pressure adjusting liquid BF to the liquid chamber 146 will be described. FIG. 5 is an explanatory diagram schematically illustrating the distribution and shape of the internal pressure in the liquid channel 190 in which the internal pressure is appropriately maintained.

The upper part of FIG. 5 shows a model (internal pressure consideration model) of the liquid circulation device 100 for considering the internal pressure in the liquid flow path 190. As shown in the figure, in the internal pressure consideration model, the liquid flow path 190 is shown on a straight line for easy consideration. Further, an end point connected to the pump discharge flow path 142 in the liquid flow path 190 is defined as a flow path start point S, and an end point defined as the pump suction flow path 144 is defined as a flow path end point E. Further, let L be the length from the flow path start point S to the flow path end point E in the liquid flow path 190. In FIG. 5, the flow path end point E and the pump suction flow path 144 are shown as separated from each other, but in the actual liquid circulation apparatus 100, the flow path end point E and the pump suction flow path 144 are connected. Has been. The broken-line arrows shown in the figure indicate the direction in which the liquid flows. Further, the internal pressure at the flow path start point S in the operation state of the circulation pump 110 is the pressure Pout, and the internal pressure at the flow path end point E in the operation state of the circulation pump 110 is Pin.
And

  The circulation pump 110 pressurizes the liquid flowing into the pump chamber 130 from the pump suction flow path 144 and pumps the liquid from the pump discharge flow path 142 toward the liquid flow path 190. A pressure gradient is generated in the internal pressure of the liquid flow path 190 by the liquid pumping by the circulation pump 110, and the liquid flows due to the generated pressure gradient. In the internal pressure consideration model, the pump chamber 130 further applies a pressure of ΔPs to the liquid flowing into the pump chamber 130 with the internal pressure Pin by driving the piezoelectric element 114. Therefore, in the internal pressure consideration model, the relationship Pin + ΔPs = Pout is established. In this embodiment, the internal pressure of the liquid flow path 190 is considered by such an internal pressure consideration model.

  The middle part of FIG. 5 shows an internal pressure distribution model of the liquid channel 190 in a state where the internal pressure is appropriate. In the internal pressure distribution model, the horizontal axis is the position x from the flow path start point S in the liquid flow path 190, and the vertical axis is the internal pressure P (x) at the position x. As described above, in this embodiment, the state where the internal pressure is appropriate means that the internal pressure is equal to or higher than the atmospheric pressure. Therefore, in the internal pressure distribution model in this embodiment, the internal pressure Pin at the flow path end point E (x = L) where the internal pressure is the lowest is the atmospheric pressure. In FIG. 5, the pressure is indicated by relative atmospheric pressure (referenced to atmospheric pressure). In this case, considering the above-described relationship of Pin + ΔPs = Pout, the internal pressure at the flow path starting point S is Pout = Ps.

  In this embodiment, the pressure gradient in the liquid channel 190 adopts a linear model. Therefore, the relationship between P (x) and position x can be expressed by the following equation (5). In this embodiment, such an internal pressure distribution model is adopted. In this embodiment, P (x) is linear, but P (x) may be an attenuation curve or a quadratic curve.

  The lower part of FIG. 5 shows a schematic diagram of the shape of the liquid channel 190 in a state where the internal pressure is appropriate. That is, the shape of the liquid flow path 190 in the case where the internal pressure is distributed as P (x) shown in the middle part of FIG. 5 is schematically shown. As shown in the figure, the shape of the liquid flow path 190 before the internal pressure changes (stopped) is indicated by a broken line, and the portion where the shape of the liquid flow path 190 is changed by the change of the internal pressure due to the operation of the circulation pump 110 is shaded It showed in. Note that the internal pressure in the stopped state is atmospheric pressure almost uniformly. As described above, the liquid channel 190 is a flexible tube. In this case, since the internal pressure is equal to or higher than the atmospheric pressure, the liquid flow path 190 is distorted outward due to the outward force due to the pressure difference. That is, when the internal pressure changes as in the middle stage of FIG. 5, the liquid flow path 190 expands and the volume inside the liquid flow path 190 increases. Assuming that the Young's modulus of the tubes constituting the liquid flow path 190 is uniform without depending on the position x, the outward strain amount of the liquid flow path 190 at each position x of the liquid flow path 190 is as follows. It becomes a value corresponding to the magnitude of the internal pressure P (x). Since the internal pressure is linear with respect to the position x of the liquid flow path 190, the distortion amount of the liquid flow path 190 is also linear with respect to the position x.

  Here, the liquid flow path when the internal pressure is uniformly changed from the atmospheric pressure state (stopped state of the circulation pump 110) to the internal pressure distribution state (operating state of the circulation pump 110) shown in FIG. When the ratio between the internal pressure P (x) of 190 and the increase amount of the channel cross-sectional area is Se, and the volume change amount per minute length Δx of the liquid channel 190 is ΔVe (x), the following equation (6) The relationship holds. Note that Se is a constant determined by the Young's modulus, Poisson's ratio, inner diameter, and outer diameter of the tube constituting the liquid flow path 190, and is constant regardless of the position x of the flow path.

Therefore, if the volume change amount in the entire liquid channel 190 (length L) is ΔVs, ΔVs is expressed as the following equation (7).

  Furthermore, when the compliance of the liquid flow path 190 is Cs, the compliance Cs is a ratio between the internal pressure and the increase in the internal volume when the internal pressure is uniformly applied to the liquid flow path 190. It is represented by the product of the length L. Therefore, since the relationship of the following formula (8) is established, the formula (7) can be expressed as the following formula (9).

  Further, when Expression (5) is applied as the internal pressure P (x), Expression (9) is expressed as the following Expression (10).

  That is, by supplying a liquid of ΔVs (= 1/2 · Cs · Ps) to the liquid flow path 190 as compared with the stopped state, the circulation pump 110 is operated while maintaining the pressure in an appropriate state. Can do. In the present embodiment, the pressure adjustment liquid BF previously stored in the film pack 160 is used as the liquid corresponding to the volume change amount ΔVs of the liquid flow path 190. Specifically, the pressure adjustment liquid BF is stored in the film pack 160 when the circulation pump 110 is stopped, and the pressure adjustment liquid BF is supplied to the liquid chamber 146 when the circulation pump 110 is operating.

  A value satisfying the following equation (11) is applied as the volume Vb of the pressure adjusting liquid BF accommodated in the film pack 160 when the circulation pump 110 is stopped. In equation (11), γ is a coefficient. “Γ ≧ 0.8” is set so that the circulation pump 110 can be used even when the volume Vb of the pressure adjusting liquid BF stored in the film pack 160 is slightly smaller than the volume change amount ΔVs of the liquid flow path 190. It is intended to work.

  The pressure adjusting liquid BF having a volume Vb accommodated in the film pack 160 is automatically supplied into the pump chamber 130 by the atmospheric pressure applied to the film pack 160 when the circulation pump 110 starts operation. Specifically, it is based on the following principle.

  When the operation of the circulation pump 110 is started, a pressure gradient is generated in the internal pressure of the liquid channel 190. The pressure gradient of the internal pressure causes the liquid flow path 190 to deform. At that time, the internal pressure (Pout) of the flow path start point S in the liquid flow path 190 moves in a direction that increases due to the pressure increase of ΔPs by the circulation pump 110. As a result, the liquid channel 190 in the vicinity of the channel start point S expands. When the flow path start point S of the liquid flow path 190 expands, the liquid works in a direction in which the liquid supplements the expanded volume, so that the volume of liquid near the flow path end point E decreases and the internal pressure near the flow path end point E decreases. Move in the direction. At that time, the pressure adjusting liquid BF is supplied from the film pack 160 to the liquid chamber 146 due to the pressure difference between the vicinity of the flow path end point E and the film pack 160. Then, the volume adjustment amount ΔVs of the liquid flow path 190 is supplemented by the supplied pressure adjustment liquid BF of the volume Vb, and the internal pressure of the liquid flow path 190 is maintained in an appropriate state. Further, when the volume Vb of the pressure adjusting liquid BF accommodated in the film pack 160 is insufficient, the flow path is deformed in the internal direction of the liquid flow path 190 due to the atmospheric pressure. However, in a range (0.8 ≦ γ <1) that is slightly smaller than the volume change amount ΔVs of the liquid flow path 190, even if some deformation of the flow path in the liquid flow path 190 due to atmospheric pressure occurs, there is a large resistance. Since it does not become an element, the circulation efficiency of the liquid by the circulation pump 110 is not greatly reduced.

  As described above, the liquid circulation device 100 stores the pressure adjustment liquid BF in the film pack 160 in advance when the circulation pump 110 is stopped. When the circulation pump 110 is operated, the pressure adjusting liquid BF is supplied from the film pack 160 to the liquid chamber 146, and the pressure adjusting liquid BF compensates the volume change amount ΔVs of the liquid channel 190. Accordingly, during the operation of the circulation pump 110, the pressure adjusting liquid BF suppresses the internal pressure of the liquid flow path 190 from being greatly reduced below the atmospheric pressure, and the flow path deforms in the internal direction of the liquid flow path 190 due to the atmospheric pressure. Is avoided. As a result, in the liquid circulation device 100, a sufficient liquid channel cross-sectional area in the liquid flow channel 190 is ensured, and a reduction in circulation efficiency can be prevented. Further, the pressure adjusting liquid BF stored in the film pack 160 is automatically supplied to the liquid chamber 146 due to the pressure difference between the internal pressure in the vicinity of the flow path end point E and the atmospheric pressure applied to the film pack 160. Separately, it is not necessary to control the supply of the pressure adjusting liquid BF using a pressure sensor or the like.

Also, if the liquid circulation device 100 does not include the film pack 160, in order to maintain an appropriate internal pressure in the operating state, a liquid of volume Vb is supplied to the liquid channel 190 when the circulation pump 110 is stopped. It is better to replenish additionally so that the internal pressure becomes atmospheric pressure or higher in the stopped state. In this case, since the liquid channel 190 is expanded from its normal shape to a steady state in the stopped state, and the load is applied to the liquid channel 190, the entire liquid channel 190 (particularly the flow channel 190). The durability in the vicinity of the road end point E) decreases. In the liquid circulation device 100 according to the present embodiment, the pressure adjustment liquid BF is accommodated in the film pack 160 when the circulation pump 110 is stopped. Therefore, the internal pressure is increased in the liquid flow path 190 when the circulation pump 110 is stopped. Since the pressure can be maintained and an unnecessary load due to the internal pressure can be avoided from being applied to the liquid flow path 190, the durability particularly near the flow path end point E is improved.

B. Second embodiment:
Next, a second embodiment of the present invention will be described. In the second embodiment, a liquid circulation device 200 is used instead of the liquid circulation device 100 as the liquid circulation device. Although the liquid circulation device 100 in the first embodiment stores the pressure adjusting liquid BF in the film pack 160, the liquid circulation device 200 in the second embodiment is provided in the liquid flow path 190 instead of the film pack 160. The pressure adjusting liquid BF is accommodated in the branch channel 210. Since the configuration other than the branch flow path 210 is the same as that of the first embodiment, the description of the configuration other than the branch flow path 210 is omitted. In addition, the same code | symbol is used about the same structure in 1st Example and 2nd Example.

  FIG. 6 is an explanatory diagram illustrating the configuration of the branch flow path 210 in the present embodiment. The branch channel 210 is provided at a position in the liquid channel 190 close to the pump suction channel 144. The branch flow path 210 is made of a material having a high gas barrier property and is less likely to volatilize the internal liquid. In the branch flow path 210, the liquid that circulates through the liquid flow path 190 by the operation of the circulation pump 110 is accommodated, including the pressure adjusting liquid BF. Hereinafter, the liquid circulating through the circulation pump 110 and the liquid flow path 190 is also referred to as a first liquid Lq1.

  The branch flow path 210 is installed so that the position of the liquid head of the first liquid Lq1 is higher than the circulation pump 110. A first liquid Lq1 having a volume Vb is accommodated in the branch flow path 210, and functions as the pressure adjusting liquid BF in the operation state of the circulation pump 110.

  As illustrated, the branch channel 210 includes a movable portion 216 therein. The branch flow path 210 has a vent hole 218 as an air flow path, and is configured such that the movable portion 216 is in contact with outside air. The movable part 216 includes a second liquid Lq2 and a high viscosity gel liquid 214. The second liquid Lq2 is located in contact with the liquid head of the first liquid Lq1. When the position of the liquid head of the first liquid Lq1 moves, the movable portion 216 moves in the height direction of the branch flow path 210 while being in contact with the liquid head of the first liquid Lq1. The inner wall surface of the branch flow path 210 has a smooth surface so that the movable part 216 can move smoothly. In addition, the liquid circulation device 200 includes a sensor 230 that can measure the amount of movement of the movable part 216 in the vicinity of the branch channel 210, and can measure the amount of movement of the movable part 216.

  The high-viscosity gel-like liquid 214 that is a component of the movable part 216 is sealed as a sealing material for preventing leakage of the first liquid Lq1 from the branch flow path 210 and preventing evaporation. The high-viscosity gel-like liquid 214 is based on polybutene having an average molecular weight of 630 and has viscoelasticity and transparency. As the high-viscosity gelled liquid 214, polybutene, α-olefin, or the like having an average molecular weight of 300 to 3700 can be used.

  Moreover, it is desirable that the high-viscosity gel-like liquid 214 is substantially incompatible with the first liquid Lq1. When an oily medium is used for the first liquid Lq1, an aqueous high-viscosity gel using water as a medium can be used. When the aqueous high-viscosity gel-like liquid 214 is used and the gas permeability of the high-viscosity gel-like liquid 214 is high or it is easy to dry, an organic solvent is further added on the high-viscosity gel-like liquid 214. An oily layer as a solvent may be formed to prevent permeation and drying.

  The second liquid Lq2 is accommodated in the branch flow path 210 in order to prevent the high-viscosity gel-like liquid 214 from dissolving in the first liquid Lq1. The second liquid Lq2 is a liquid having a larger heat of vaporization than the first liquid Lq1, and is a liquid that can be phase-separated from the first liquid Lq1. Further, the density of the second liquid Lq2 is smaller than that of the first liquid Lq1. In this embodiment, liquid paraffin is used as the second liquid Lq2. In addition, calcium alginate can be used as the second liquid Lq2. Since the movable part 216 has the above configuration, the first liquid Lq1 does not directly contact the atmosphere.

  In the liquid circulation device 200 having the above-described configuration, when the circulation pump 110 operates, a pressure gradient is generated in the internal pressure of the liquid flow path 190 as described in the first embodiment. Then, due to the volume change of the liquid channel 190, the pressure in the vicinity of the channel end point E of the liquid channel 190 moves in the direction of decreasing. At that time, due to the pressure difference between the internal pressure in the vicinity of the flow path end point E and the atmospheric pressure applied to the branch flow path 210, the first liquid Lq1 (corresponding to the pressure adjusting liquid BF) in the branch flow path 210 enters the liquid flow path 190. Supplied. As a result, the internal pressure of the liquid flow path 190 is maintained at atmospheric pressure or higher, and the circulation pump 110 can operate with the internal pressure being in an appropriate state.

  As described above, the liquid circulation device 200 includes the branch flow path 210 that stores the first liquid Lq1 as the pressure adjusting liquid BF. Therefore, in the operating state of the circulation pump 110, as in the first embodiment, the liquid circulation device 200 is provided. It is possible to suppress the internal pressure of the flow path 190 from being significantly lower than the atmospheric pressure, and to operate in an appropriate state. In addition, since the branch channel 210 includes the movable portion 216, the first liquid Lq1 is prevented from leaking outside from the branch channel, and further, the first liquid Lq1 is prevented from being diffused. Can do.

  Further, since the liquid circulation device 200 includes the sensor 230, it is possible to measure the amount of movement of the movable part 216 when the circulation pump 110 changes from the stopped state to the operating state. Based on the measured moving amount of the movable part 216, the amount of the first liquid Lq1 supplied to the liquid channel 190 as the pressure adjustment liquid BF can be acquired. Since the supply amount of the pressure adjusting liquid BF is equal to the volume change amount of the liquid channel 190, as a result, the state of the internal pressure of the liquid channel 190 in the operating state can be acquired in real time.

C. Variations:
The present invention is not limited to the above-described examples and embodiments, and can be carried out in various modes without departing from the gist thereof. For example, the following modifications are possible.
(C1) Modification 1:
In the above embodiment, the liquid circulation device 100 is used to cool the piezoelectric actuator 34 of the liquid ejecting device 20 (water jet knife). However, the liquid circulation device 100 may be used to adjust the temperature of other medical devices other than the water jet knife. For example, the liquid circulation device 100 may be used to adjust the temperature of a motor unit of a medical drill, an ultrasonic generator of an ultrasonic scaler that removes tartar by ultrasonic waves, and injects a medical solution into a living body. A jetting device may be used. Further, the liquid circulation device 100 is not limited to the case where it is used for cooling the heat generating part, but may be used when heating an object. For example, it can be used when a part of a human body is heated or kept warm. In this case, it can be realized by providing the liquid circulating apparatus 100 with a heating unit for heating the circulating liquid. In particular, in a medical device that places importance on safety, the liquid circulation device 100 can be applied to a medical device in order to ensure stable circulation efficiency.

(C2) Modification 2:
In the above embodiment, a liquid, particularly water, is used as the liquid circulating in the liquid circulation device 100, but various liquids can be used without being limited thereto. For example, nitrogen or carbon dioxide may be employed as the gas. In addition to water, oil may be used as the liquid, and the liquid is not limited to water or oil as long as heat exchange is possible.

(C3) Modification 3:
In the above embodiment, a film pack is used as the liquid storage chamber. However, the present invention is not limited to this, and for example, a liquid storage chamber formed of a casing having a diaphragm may be used. In addition, a liquid storage chamber that can be deformed according to the amount of liquid stored, such as an elastic bag-shaped rubber pack or a bellows, may be employed. Even if such a liquid storage chamber is employed, the same effect as in the above embodiment can be obtained.

(C4) Modification 4:
In the second embodiment, the branch flow path 210 includes the movable portion 216, but a branch flow path that does not include the movable portion may be employed. By doing in this way, the structure of a branch flow path can be simplified.

(C5) Modification 5:
In the above-described embodiment, the piezoelectric element is employed as the operating element. However, the present invention is not limited thereto, and various elements may be employed. For example, driving elements such as electrostrictive elements, electromagnetic actuators, electrostatic actuators, and dielectric polyactuators can be used. Even if these driving elements are employed, the same effects as in the above-described embodiment can be obtained. In the above-described embodiment, the stacked type is used as the piezoelectric element, but in addition, a piezoelectric element of a single crystal, a monomorph type, or a bimorph type piezoelectric element may be used.

(C6) Modification 6:
In the above embodiment, the check valve 148 is employed as the liquid resistance element in the above embodiment. However, the present invention is not limited to this, and various liquid resistance elements can be employed. FIG. 7 is an explanatory view showing a liquid resistance element that can be employed. The illustrated liquid resistance element (A) is a check valve installed at a position different from the first embodiment. The liquid resistance element (B) suppresses the flow of liquid from the pump chamber 130 to the liquid chamber 146 without using a check valve. The liquid resistance element (C) has a configuration in which the check valve 148 is not installed in the above embodiment. Even if it is a liquid resistance element (C), the flow of the liquid from the pump chamber 130 to the liquid chamber 146 can be suppressed with the shape. Moreover, since the liquid resistance element (B) and the liquid resistance element (C) do not have a movable part like the check valve 148, durability can be improved.

DESCRIPTION OF SYMBOLS 10 ... Liquid injection system 20 ... Liquid injection apparatus 30 ... Pulsation generating part 32 ... Liquid chamber 34 ... Piezoelectric actuator 36 ... Liquid injection pipe 38 ... Lower case 39 ... Upper case 40 ... Liquid container 42 ... Supply pump 44 ... Connection tube 46 ... Connection tube 100 ... Liquid circulation device 110 ... circulation pump 112 ... piezoelectric element case 114 ... piezoelectric element 116 ... reinforcing plate 118 ... diaphragm 120 ... annular member 130 ... pump chamber 140 ... channel case 140C ... concave 142 ... pump discharge channel 144 ... Pump suction channel 146 ... Liquid chamber 148 ... Check valve 160 ... Film pack 162 ... Connecting member 162a ... Communication hole 164 ... Film 166 ... Opening port member 190 ... Liquid channel 200 ... Liquid circulation device 210 ... Branch channel 214 ... high-viscosity gel liquid 216 ... movable part 218 ... vent hole 23 0 ... sensor S ... flow path start point E ... flow path end point BF ... pressure adjusting liquid Pout ... internal pressure at start point S Pin ... internal pressure at end point L Lq1 ... first liquid Lq2 ... second liquid

Claims (11)

A liquid circulation device that circulates liquid without contact with the atmosphere,
A pump chamber whose volume is changed by the volume changing means;
An inlet channel which is an inflow channel of liquid to the pump chamber;
A liquid resistance element that suppresses or inhibits the flow of the liquid from the pump chamber toward the inlet channel;
An outlet channel which is an outlet of liquid from the pump chamber;
A circulation channel of length L through which the liquid circulates from the outlet channel to the inlet channel;
A pressure adjusting mechanism for storing the liquid of volume Vb when the volume changing means is not operating and for supplying the stored liquid as part of the circulating liquid when the volume changing means is operating. And
The compliance of the circulation channel is Cs,
When the pressure of the liquid at the time of the operation of the volume changing means in the circulation channel at a position of length x from the outlet channel is P (x),
The volume Vb satisfies the relationship of the formula (1).

The liquid circulation device according to claim 1,
When the pressure of the liquid flowing into the circulation channel from the outlet channel is Ps, the volume Vb satisfies the relationship of the formula (2).

The liquid circulation device according to claim 1 or 2,
The pressure adjusting mechanism includes a liquid storage chamber for storing the liquid used for the supply, and is deformable according to the amount of the liquid stored in the inside. The liquid circulation device according to claim 3,
The liquid storage chamber is a pack formed by sealing a film in a bag shape. The liquid circulation device according to claim 4,
The liquid storage chamber is detachable from the liquid circulation device. The liquid circulation device according to any one of claims 1 to 5,
The pressure adjusting mechanism includes a branch channel branched from the circulation channel. The liquid circulation device according to claim 6,
A sealing material that seals the stored liquid and moves according to a pressure difference between the pressure of the liquid in the branch channel and atmospheric pressure is disposed inside the branch channel. Is a liquid circulation device. The liquid circulation device according to claim 7,
The liquid is a first liquid;
A second liquid that can be phase-separated from the first liquid is sealed between the first liquid and the sealing material inside the branch flow path,
The heat of vaporization of the second liquid is greater than the heat of vaporization of the first liquid. A liquid circulation device according to any one of claims 1 to 8,
The volume changing means uses an operating element that operates according to a change in voltage.   A medical device using the liquid circulation device according to any one of claims 1 to 9.   A liquid ejecting apparatus using the liquid circulating apparatus according to any one of claims 1 to 9.

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