U.S. patent application number 13/788153 was filed with the patent office on 2013-09-19 for liquid circulating device and medical apparatus.
This patent application is currently assigned to SEIKO EPSON CORPORATION. The applicant listed for this patent is SEIKO EPSON CORPORATION. Invention is credited to Atsuya HIRABAYASHI, Takahiro MATSUZAKI, Atsushi OSHIMA, Takeshi SETO, Kazuaki UCHIDA.
Application Number | 20130243616 13/788153 |
Document ID | / |
Family ID | 49126931 |
Filed Date | 2013-09-19 |
United States Patent
Application |
20130243616 |
Kind Code |
A1 |
SETO; Takeshi ; et
al. |
September 19, 2013 |
LIQUID CIRCULATING DEVICE AND MEDICAL APPARATUS
Abstract
A liquid circulating device includes a pump chamber whose volume
is changed by a volume changing unit; an inlet channel that is an
inflow passage of the liquid to the pump chamber; a liquid
resistance element; an outlet channel; a circulation channel of a
length L through which the liquid circulates from the outlet
channel to the inlet channel; and a pressure regulating mechanism
that contains the liquid of a volume Vb during the non-operation of
the volume changing unit and supplies the contained liquid as part
of the circulating liquid during the operation of the volume
changing unit. When the compliance of the circulation channel is
defined as Cs, and the pressure of the liquid in the circulation
channel at the position of a length x from the outlet channel
during the operation of the volume changing unit is defined as
P(x), the volume Vb satisfies a predetermined relationship.
Inventors: |
SETO; Takeshi; (Tokyo-to,
JP) ; OSHIMA; Atsushi; (Shiojiri-shi, JP) ;
MATSUZAKI; Takahiro; (Shiojiri-shi, JP) ; UCHIDA;
Kazuaki; (Nagano-ken, JP) ; HIRABAYASHI; Atsuya;
(Chino-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SEIKO EPSON CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
SEIKO EPSON CORPORATION
Tokyo
JP
|
Family ID: |
49126931 |
Appl. No.: |
13/788153 |
Filed: |
March 7, 2013 |
Current U.S.
Class: |
417/212 |
Current CPC
Class: |
F04B 43/095 20130101;
F04B 23/00 20130101; A61B 17/3203 20130101 |
Class at
Publication: |
417/212 |
International
Class: |
F04B 23/00 20060101
F04B023/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 15, 2012 |
JP |
2012-059234 |
Nov 13, 2012 |
JP |
2012-249060 |
Claims
1. A medical apparatus that circulates a liquid in non-contact with
the atmospheric air, comprising: a pump chamber whose volume is
changed by a volume changing unit; an inlet channel that is an
inflow passage of the liquid to the pump chamber; a liquid
resistance element that controls or stops the flow of the liquid
that flows from the pump chamber to the inlet channel; an outlet
channel that is an outflow port of the liquid from the pump
chamber; a circulation channel of a length L through which the
liquid circulates from the outlet channel to the inlet channel; and
a pressure regulating mechanism that contains the liquid of a
volume Vb during the non-operation of the volume changing unit and
supplies the contained liquid as part of the circulating liquid
during the operation of the volume changing unit, wherein when the
compliance of the circulation channel is defined as Cs, and the
pressure of the liquid in the circulation channel at the position
of a length x from the outlet channel during the operation of the
volume changing unit is defined as P(x), the volume Vb satisfies
the relationship of Formula (1): Vb .gtoreq. .gamma. 1 L .intg. 0 L
Cs P ( x ) x ( .gamma. .gtoreq. 0.8 ) . ( 1 ) ##EQU00005##
2. The medical apparatus according to claim 1, wherein the volume
Vb satisfies the relationship of Formula (2) when the pressure of
the liquid that flows into the circulation channel from the outlet
channel is defined as Ps: Vb.gtoreq..gamma.1/2CsPs
(.gamma..gtoreq.0.8) (2)
3. The medical apparatus according to claim 1, wherein the pressure
regulating mechanism includes a liquid containing chamber that
contains the liquid to be used for the supply, and is deformable
according to the amount of the liquid contained inside the liquid
containing chamber.
4. The medical apparatus according to claim 3, wherein the liquid
containing chamber is a pack formed by sealing films in the shape
of a bag.
5. The medical apparatus according to claim 4, wherein the liquid
containing chamber is attachable to and detachable from the liquid
circulating device.
6. The medical apparatus according to claim 1, wherein the pressure
regulating mechanism includes a branch channel that branches from
the circulation channel.
7. The medical apparatus according to claim 6, wherein a sealing
material that seals the contained liquid moves according to the
pressure differential between the pressure of the liquid within the
branch channel and the atmospheric pressure is arranged inside the
branch channel.
8. The medical apparatus according to claim 7, wherein the liquid
is a first liquid, a second liquid that is phase-separable from the
first liquid is sealed between the first liquid and the sealing
material inside the branch channel, and the vaporization heat of
the second liquid is greater than the vaporization heat of the
first liquid.
9. The medical apparatus according to claim 1, wherein the volume
changing unit uses an operating element that operates depending on
a change in voltage.
10. A medical apparatus circulates a liquid in non-contact with the
atmospheric air according to claim 1.
11. A liquid circulating device comprising: a pump chamber whose
volume is changed by a volume changing unit; an inlet channel that
is an inflow passage of the liquid to the pump chamber; a liquid
resistance element that controls or stops the flow of the liquid
that flows from the pump chamber to the inlet channel; an outlet
channel that is an outflow port of the liquid from the pump
chamber; a circulation channel of a length L through which the
liquid circulates from the outlet channel to the inlet channel; and
a pressure regulating mechanism that contains the liquid of a
volume Vb during the non-operation of the volume changing unit and
supplies the contained liquid as part of the circulating liquid
during the operation of the volume changing unit, wherein when the
compliance of the circulation channel is defined as Cs, and the
pressure of the liquid in the circulation channel at the position
of a length x from the outlet channel during the operation of the
volume changing unit is defined as P(x), the volume Vb satisfies
the relationship of Formula (1): Vb .gtoreq. .gamma. 1 L .intg. 0 L
Cs P ( x ) x ( .gamma. .gtoreq. 0.8 ) . ( 1 ) ##EQU00006##
12. The medical apparatus according to claim 11, wherein the volume
Vb satisfies the relationship of Formula (2) when the pressure of
the liquid that flows into the circulation channel from the outlet
channel is defined as Ps: Vb.gtoreq..gamma.1/2CsPs
(.gamma..gtoreq.0.8) (2)
13. The medical apparatus according to claim 11, wherein the
pressure regulating mechanism includes a liquid containing chamber
that contains the liquid to be used for the supply, and is
deformable according to the amount of the liquid contained inside
the liquid containing chamber.
14. The medical apparatus according to claim 13, wherein the liquid
containing chamber is a pack formed by sealing films in the shape
of a bag.
15. The medical apparatus according to claim 14, wherein the liquid
containing chamber is attachable to and detachable from the liquid
circulating device.
16. The medical apparatus according to claim 11, wherein the
pressure regulating mechanism includes a branch channel that
branches from the circulation channel.
17. The medical apparatus according to claim 16, wherein a sealing
material that seals the contained liquid moves according to the
pressure differential between the pressure of the liquid within the
branch channel and the atmospheric pressure is arranged inside the
branch channel.
18. The medical apparatus according to claim 17, wherein the liquid
is a first liquid, a second liquid that is phase-separable from the
first liquid is sealed between the first liquid and the sealing
material inside the branch channel, and the vaporization heat of
the second liquid is greater than the vaporization heat of the
first liquid.
19. The medical apparatus according to claim 11, wherein the volume
changing unit uses an operating element that operates depending on
a change in voltage.
20. A medical apparatus that circulates a liquid in non-contact
with the atmospheric air, comprising: a pump chamber whose volume
is changed by a volume changing unit; an inlet channel that is an
inflow passage of the liquid to the pump chamber; an outlet channel
that is an outflow port of the liquid from the pump chamber; a
circulation channel of a length L through which the liquid
circulates from the outlet channel to the inlet channel; and a
pressure regulating mechanism that contains the liquid of a volume
Vb during the non-operation of the volume changing unit and
supplies the contained liquid as part of the circulating liquid
during the operation of the volume changing unit, wherein when the
compliance of the circulation channel is defined as Cs, and the
pressure of the liquid in the circulation channel at the position
of a length x from the outlet channel during the operation of the
volume changing unit is defined as P(x), the volume Vb satisfies
the relationship of Formula (1): Vb .gtoreq. .gamma. 1 L .intg. 0 L
Cs P ( x ) x ( .gamma. .gtoreq. 0.8 ) . ( 1 ) ##EQU00007##
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The present invention relates to a liquid circulating
device.
[0003] 2. Related Art
[0004] In the related art, a technique using a liquid circulating
device is known as the technique for adjusting the temperature of
an object (for example, JP-A-8-242463). This technique brings a
circulation channel, through which a liquid circulates, into
contact with a target (hereinafter referred to as a temperature
adjustment target) whose temperature is intended to be adjusted,
and adjusts the temperature of the temperature adjustment target
depending on the temperature of the liquid that is circulated.
However, since the liquid circulating device of the related art is
not configured in consideration of the pressure inside the
circulation channel during the operation, problems that occur,
depending on operating conditions, are for example, the
cross-sectional area of the channel becomes small, and a decrease
of circulation efficiency of the liquid have been pointed out.
SUMMARY
[0005] An advantage of some aspects of the invention is to ensure
stability of circulation efficiency.
[0006] The invention can be implemented as the following forms or
application examples.
Application Example 1
[0007] Application Example 1 is directed to a liquid circulating
device that circulates a liquid in non-contact with the atmospheric
air. The liquid circulating device includes a pump chamber whose
volume is changed by a volume changing unit; an inlet channel that
is an inflow passage of the liquid to the pump chamber; a liquid
resistance element that controls or stops the flow of the liquid
that flows from the pump chamber to the inlet channel; an outlet
channel that is an outflow port of the liquid from the pump
chamber; a circulation channel of a length L through which the
liquid circulates from the outlet channel to the inlet channel; and
a pressure regulating mechanism that contains the liquid of a
volume Vb during the non-operation of the volume changing unit and
supplies the contained liquid as part of the circulating liquid
during the operation of the volume changing unit. When the
compliance of the circulation channel is defined as Cs, and the
pressure of the liquid in the circulation channel during the
operation of the volume changing unit at the position of a length x
from the outlet channel is defined as P(x), the volume Vb satisfies
the relationship of Formula (3).
Vb .gtoreq. .gamma. 1 L .intg. 0 L Cs P ( x ) x ( .gamma. .gtoreq.
0.8 ) ( 3 ) ##EQU00001##
[0008] According to this liquid circulating device, the pressure
regulating mechanism supplies the liquid of a volume Vb contained
in the pressure regulating mechanism, as part of the circulating
liquid that circulates through the circulation channel, during the
operation of the volume changing unit. Accordingly, the pressure
inside the circulation channel during the operation of the volume
changing unit can be kept from dropping significantly.
Additionally, when .gamma. is set to one or more and the liquid of
the volume Vb is contained in the pressure regulating mechanism,
the value of the pressure P(x) inside the circulation channel
during the operation of the volume changing unit can be kept from
becoming equal to or lower than the pressure inside the circulation
channel during the non-operation of the volume changing unit.
Accordingly, the circulation efficiency can be stably secured.
Application Example 2
[0009] In the liquid circulating device according to Application
Example 1, the volume Vb may satisfy the relationship of Formula
(4) when the pressure of the liquid that flows out to the
circulation channel from the outlet channel is defined as Ps.
Vb.gtoreq..gamma.1/2CsPs
(.gamma..gtoreq.0.8) (4)
[0010] According to this liquid circulating device, the pressure
regulating mechanism supplies the liquid of a volume Vb contained
in the pressure regulating mechanism, as part of the circulating
liquid that circulates through the circulation channel, during the
operation of the volume changing unit. Accordingly, the pressure
inside the circulation channel during the operation of the volume
changing unit can be kept from dropping significantly.
Particularly, if .gamma. is set to one or more and the liquid of
the volume Vb is contained in the pressure regulating mechanism,
the pressure inside the circulation channel during the operation of
the volume changing unit can be more reliably kept from becoming
equal to or lower than the pressure inside the circulation channel
during the non-operation of the volume changing unit.
Application Example 3
[0011] In the liquid circulating device according to Application
Example 1 or 2, the pressure regulating mechanism may include a
liquid containing chamber that contains the liquid to be used for
the supply, and may be deformable according to the amount of the
liquid contained inside the liquid containing chamber.
[0012] According to this liquid circulating device, the liquid
containing chamber that is deformable according to the amount of
the liquid contained therein is used as the pressure regulating
mechanism. Thus, the internal pressure can be maintained in a
predetermined range even if the amount of the liquid contained
therein changes.
Application Example 4
[0013] In the liquid circulating device according to Application
Example 3, the liquid containing chamber may be a pack formed by
sealing films in the shape of a bag.
[0014] According to this liquid circulating device, the pack is
used as the pressure regulating mechanism. Thus, a configuration in
which the liquid can be easily supplied can be provided.
Application Example 5
[0015] In the liquid circulating device according to Application
Example 4, the liquid containing chamber may be attachable to and
detachable from the liquid circulating device.
[0016] According to this liquid circulating device, the liquid
containing chamber is attachable and detachable. Thus, only the
liquid containing chamber can be replaced.
Application Example 6
[0017] In the liquid circulating device according to any one of
Application Examples 1 to 5, the pressure regulating mechanism may
include a branch channel that branches from the circulation
channel.
[0018] According to this liquid circulating device, the branch
circuit is used as the pressure regulating mechanism. Thus, the
liquid can be easily supplied.
Application Example 7
[0019] In the liquid circulating device according to Application
Example 6, a sealing material that seals the contained liquid and
moves according to the pressure differential between the pressure
of the liquid within the branch channel and atmospheric pressure
may be arranged inside the branch channel.
[0020] According to this liquid circulating device, the sealing
material is arranged in the branch channel. Thus, the liquid can be
prevented from flowing out of the branch channel. Since the sealing
material moves according to the pressure differential between the
pressure of the liquid within the branch channel and the
atmospheric pressure, the internal pressure can be maintained in a
predetermined range.
Application Example 8
[0021] In the liquid circulating device according to Application
Example 7, the liquid may be a first liquid, a second liquid that
is phase-separable from the first liquid, and may be sealed between
the first liquid and the sealing material inside the branch
channel, and the vaporization heat of the second liquid may be
greater than the vaporization heat of the first liquid.
[0022] According to this liquid circulating device, the first
liquid can be kept from evaporating from the branch channel.
Application Example 9
[0023] In the liquid circulating device according to any one of
Application Examples 1 to 8, the volume changing unit may use an
operating element that operates depending on a change in
voltage.
[0024] According to this liquid ejecting apparatus, a change in the
volume of the pump chamber can be electrically controlled.
Application Example 10
[0025] Application Example 10 is directed to a medical apparatus
using the liquid circulating device according to any one of
Application Examples 1 to 9.
[0026] According to this medical apparatus, a liquid circulating
device that stably ensures the circulation efficiency can be
used.
Application Example 11
[0027] Application Example 11 is directed to a liquid ejecting
apparatus using the liquid circulating device according to any one
of Application Examples 1 to 9.
[0028] According to this liquid ejecting apparatus, a liquid
circulating device that stably ensures the circulation efficiency
can be used.
[0029] In addition, the invention can be realized in various
aspects. For example, the invention can be realized in forms of a
liquid circulating system, a temperature adjusting device, or the
like, other than a liquid circulating method and a liquid
circulating device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] The invention will be described with reference to the
accompanying drawings, wherein like numbers reference like
elements.
[0031] FIG. 1 is an explanatory view showing the schematic
configuration of a liquid ejecting system.
[0032] FIG. 2 is a schematic view schematically showing the
configuration of a liquid circulating device.
[0033] FIGS. 3A to 3C are explanatory views showing the flow of a
liquid inside a circulating pump.
[0034] FIGS. 4A to 4D are explanatory views showing the
configuration of a film pack.
[0035] FIG. 5 is an explanatory view illustrating a liquid channel
where internal pressure is appropriately maintained.
[0036] FIG. 6 is an explanatory view illustrating the configuration
of a branch channel.
[0037] FIGS. 7A to 7C are explanatory views illustrating
Modification Example 6.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
A. First Example
A1. System Configuration:
[0038] Embodiments of the invention will be described on the basis
of examples. FIG. 1 is an explanatory view showing the schematic
configuration of a liquid ejecting system 10 as one example of the
invention. The liquid ejecting system 10 is equipped with a liquid
ejecting apparatus 20 and a liquid circulating device 100 that
cools the liquid ejecting apparatus 20. The liquid ejecting
apparatus 20 is a water jet knife that ejects a jet water stream to
living body tissues, such as the skin. Particularly, the liquid
ejecting apparatus 20 of the present example is a water jet pulse
scalpel that exfoliates and incises living body tissues.
[0039] The liquid ejecting apparatus 20 is equipped with a
pulsation generator 30 that ejects a jet water stream, a liquid
container 40 that contains water, a supply pump 42 that pumps the
water contained in the liquid container 40 to supply the water to
the pulsation generator 30, a connecting tube 44 that connects the
liquid container 40 and the supply pump 42, and a connecting tube
46 that connects the supply pump 42 and the pulsation generator
30.
[0040] The pulsation generator 30 is equipped with a liquid chamber
32 that temporarily stores the water supplied from the connecting
tube 46, a piezoelectric actuator 34 that imparts pulsation to the
water stored in the liquid chamber 32, a liquid ejecting pipe 36
that communicates with the liquid chamber 32 and allows the water
to which pulsation is imparted by the piezoelectric actuator 34 to
pass therethrough, a lower case 38 that houses the piezoelectric
actuator 34 therein, and an upper case 39 that constitutes the
liquid chamber 32 and is connected to the lower case 38.
[0041] The piezoelectric actuator 34, which is a laminated
piezoelectric element, changes the volume of the liquid chamber 32
by deforming a diaphragm using the piezoelectric effect of a
piezoelectric element. If the volume of the liquid chamber 32
becomes small, the water stored in the liquid chamber 32 is ejected
to the outside as a jet water stream through the liquid ejecting
pipe 36. Additionally, as another means for changing the volume of
the liquid chamber 32, a piston may be driven and the volume of the
liquid chamber 32 may be changed by the displacement of the
piston.
[0042] The liquid circulating device 100, which is an apparatus
that cools the piezoelectric actuator 34 of the liquid ejecting
apparatus 20, is equipped with a circulating pump 110, and a liquid
channel 190 that is a circulation channel having both ends
connected to the circulating pump 110. The liquid channel 190 is a
tube that has pressure resistance and flexibility. Although medical
tubes or general industrial tubes that are made of, for example,
fluorine-based resins, such as PTFE, polyimide-based resins,
thermoplastic resins, such as PVC-based resins, or silicone rubber
are applicable as the tube, the invention is not particularly
limited thereto. The liquid channel is wound around the
piezoelectric actuator 34. For this reason, the heat generated in
the piezoelectric actuator 34 is transmitted to the liquid
(circulation liquid) that circulates through the inside of the
liquid channel 190, and the piezoelectric actuator 34 is cooled.
The circulation liquid whose temperature has risen is cooled by
air-cooling while circulating through the liquid channel 190. In
addition, the circulation liquid may be separately cooled using a
radiator. In the present example, the circulation liquid is a
liquid in consideration of the efficiency of heat exchange. In the
liquid circulating device 100, various liquids, such as water or
oil, can be adopted as the liquid. For example, if silicone oil
with low volatility and specific viscosity is adopted in the liquid
circulating device 100, the circulation liquid does not evaporate
easily, and the liquid circulating device 100 that can be used for
a long period of time can be provided.
[0043] FIG. 2 is a schematic view schematically showing the
cross-sectional configuration of the liquid circulating device 100.
In the present example, in the liquid circulating device 100, a
hermetically closed circulation channel is constituted by the
circulating pump 110 and the liquid channel 190. The hermetically
closed circulation channel means a circulation channel that does
not have a portion where the circulation liquid comes in contact
with the outside (atmospheric air). By adopting the hermetically
closed circulation channel, bubbles, other foreign matter, or the
like can be prevented from being mixed with the circulation liquid.
Additionally, the flow rate of a liquid that circulates can be
stably secured by preventing the circulation liquid itself from
volatilizing to decrease the amount thereof, and this contributes
to maintaining stable circulation efficiency.
[0044] The circulating pump 110 is equipped with a laminated
piezoelectric element 114, a piezoelectric element case 112 that
houses the piezoelectric element 114 therein, and a channel case
140 that has a channel formed therein. The piezoelectric element
114 has a bottom portion fixed to the piezoelectric element case
112. A circular reinforcing plate 116 is attached to an upper end
of the piezoelectric element 114, and a circular diaphragm 118
formed from a metal sheet or the like is bonded to an upper face 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 a lower face of the diaphragm 118 is in
contact with an upper end face of the piezoelectric element case
112.
[0045] A recess 140C is formed on the lower face side (side that
faces the piezoelectric element case 112) of the channel case 140,
and an annular member 120 is fitted into the recess 140C. The
internal diameter of the annular member 120 is smaller than the
external diameter of the diaphragm 118. If the piezoelectric
element case 112 and the channel case 140 are made to face each
other and are fixed by screwing or the like, the diaphragm 118 is
pinched between the annular member 120 and the piezoelectric
element case 112, and the airtightness between the channel case 140
and the diaphragm 118 is brought into the state of being secured by
the annular member 120. As a result, a pump chamber 130, which is
the space surrounded by the recess 140C 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 elongates or shrinks and the diaphragm
118 is deformed.
[0046] In the channel case 140, a liquid chamber 146 that guides a
liquid to the pump chamber 130, a pump discharge channel 142 that
is connected to one end of the liquid channel 190 and guides the
liquid within the pump chamber 130 to the liquid channel 190, and a
pump suction channel 144 that is connected to the other end of the
liquid channel 190 and guides the liquid supplied from the liquid
channel 190 to the liquid chamber 146 are further formed.
[0047] The liquid chamber 146 is formed so that one end opens to
the upper face side (the side opposite to the side that faces the
piezoelectric element case 112) of the channel case 140, the other
end communicates with the pump chamber 130, and the diameter
decreases toward the pump chamber 130 side (the cross-sectional
area becomes smaller). The pump suction channel 144 is connected to
a portion where the diameter of the liquid chamber 146 decreases. A
check valve 148 is provided at the end portion of the liquid
chamber 146 on the pump chamber 130 side. The check valve 148
permits the inflow of a liquid from the liquid chamber 146 to the
pump chamber 130 and prevents the backflow of the liquid from the
pump chamber 130 to the liquid chamber 146.
[0048] A film pack 160 is airtightly connected to an opening
portion of the liquid chamber 146 formed on the upper face side of
the channel case 140 via a connecting member 162. The film pack 160
is formed from a flexible film having gas barrier properties and
heat resistance in order to prevent mixing of bubbles in the
circulation liquid. In addition, in the present example, the film
pack 160 is attachable to and detachable from the channel case 140,
and replacement of the film pack, exclusion of bubbles within the
film pack, and replenishment of the liquid becomes easy. In
addition, depending on the circulation liquid, the film does not
need to have gas barrier properties or heat resistance, and the
material of a film is appropriately selected. Additionally, in the
present example, the film pack 160 is made attachable to and
detachable from the channel case 140. However, the film pack 160
may be formed integrally with the channel case 140.
[0049] The liquid circulating device 100 configured as described
above circulates the liquid within the liquid channel 190 by
driving the piezoelectric element 114 of the circulating pump 110.
Next, the operation of the circulating pump 110 will be described
in detail.
A2. Operation of Circulating Pump 110:
[0050] FIGS. 3A to 3C are explanatory views showing the flow of a
liquid inside the circulating pump 110. FIG. 3A is an explanatory
view showing a state (state before a driving voltage is applied to
the piezoelectric element 114) where the circulating pump 110 is
not operating. Hereinafter, the state where the circulating pump
110 is operating is also referred to as an operating state, and a
state where the circulating pump 110 is not operating is also
referred to as a stopped state. In the stopped state, the pump
chamber 130 is not filled with the liquid. Additionally, in the
stopped state, a predetermined amount of liquid is contained in
advance even in the film pack 160. In the stopped state, the
pressure inside the pump chamber 130, the film pack 160, and the
liquid channel 190 is almost equal to the atmospheric pressure. The
liquid (hereinafter referred to as a pressure regulation liquid BF)
contained within the film pack 160 in the stopped state is used in
order to regulate the inside of the liquid channel 190 to an
appropriate pressure in the operating state. The pressure
regulation liquid BF will be described below in detail.
[0051] FIG. 3B is an explanatory view showing a state where a
driving voltage is applied to the piezoelectric element 114. If a
driving voltage is applied to the piezoelectric element 114 in a
state where the pump chamber 130 is filled with the liquid, the
piezoelectric element 114 elongates due to the applied driving
voltage and pushes up the diaphragm 118 in the direction of the
pump chamber 130 via the reinforcing plate 116. If the pump chamber
130 is pushed by the diaphragm 118, the volume of the pump chamber
130 decreases and the liquid within the pump chamber 130 is
pressurized. At this time, since the check valve 148 is brought
into a closed state and the backflow of the liquid from the pump
chamber 130 to the liquid chamber 146 is prevented, an amount of
liquid equivalent to the decreased volume of the pump chamber 130
is pumped toward the liquid channel 190 through the pump discharge
channel 142.
[0052] If the liquid is sent into the liquid channel 190 in this
way, the liquid within the liquid channel 190 is gradually washed
away to the downstream side. Additionally, as described above, in
the liquid circulating device 100 of the present example, a closed
system is constituted by the liquid channel 190 and the circulating
pump 110, and the liquid that has been pushed out from the liquid
channel 190 and has returned to the circulating pump 110 flows into
the film pack 160 through the pump suction channel 144. Here, the
film pack 160 is formed from a flexible film, is not in the state
of being filled with the liquid and being completely stretched, and
is attached in a state where a margin to expand is still left
behind. Accordingly, even if the liquid that has returned from the
liquid channel 190 flows into the film pack 160, as the film pack
160 expands, the pressure within the film pack 160 or the liquid
chamber 146 that communicates with the film pack 160 is kept from
increasing.
[0053] FIG. 3C is an explanatory view showing a state where a
driving voltage to be applied to the piezoelectric element 114 has
decreased. If the driving voltage decreases, the piezoelectric
element 114 shrinks and returns to its original length. Then, the
volume of the pump chamber 130 increases (restores to its original
volume). At this time, since the inside of the pump chamber 130 has
a negative pressure, the check valve 148 is brought into an open
state, and the liquid is suctioned into the pump chamber 130 from
the liquid chamber 146. In addition, the negative pressure means a
pressure equal to or lower than the atmospheric pressure.
[0054] The negative pressure in the pump chamber 130 also acts on
the pump discharge channel 142. However, the channel resistance of
the pump discharge channel 142 is defined as being greater than the
channel resistance of the liquid chamber 146 or the check valve
148. Accordingly, compared to the pump discharge channel 142, the
liquid easily flows into the pump chamber 130 from the liquid
chamber 146. Additionally, since the liquid chamber 146
communicates with the film pack 160, and the liquid within the film
pack 160 flows into the pump chamber 130 without stagnation, the
inside of the liquid chamber 146 is unlikely to have a negative
pressure.
[0055] If the piezoelectric element 114 elongates again due to an
increase in the driving voltage after the pump chamber 130 whose
volume is restored is filled with the liquid from the liquid
chamber 146 in this way, as shown in FIG. 3B, the liquid
pressurized within the pump chamber 130 is pumped toward the pump
discharge channel 142 and the liquid channel 190. As the
circulating pump 110 repeats the above operation, the liquid
circulating device 100 circulates the liquid within the liquid
channel 190.
A3. Configuration of Film Pack:
[0056] FIGS. 4A to 4D are explanatory views showing the
configuration of the film pack 160. An exploded perspective view of
the film pack 160 is shown in FIG. 4A. The film pack 160 is
constituted by a pair of flexible films 164 having gas barrier
properties and heat resistance, a connecting member 162 that has a
communication hole 162a and detachably connect the film pack 160 to
the liquid chamber 146, and an open port member 166 that is
provided with an open port that can be opened and closed. The pair
of films 164 are formed in a substantially rectangular shape. The
film pack 160 is formed by pinching the connecting member 162 on
one end side of the pair of films 164 in the longitudinal
direction, pinching the open port member 166 on the other end side,
and airtightly sticking the peripheries of the films together by
thermocompression bonding or the like.
[0057] The film pack 160 formed by sticking the pair of films 164
together is shown in FIG. 4B. In addition, in FIG. 4B, a sealed
portion stuck by thermocompression bonding or the like is shown in
a hatched fashion. As shown in FIG. 4B, the film pack 160 is
brought into a state where the pair of films 164 are in contact
with each other in a state where the liquid is not contained inside
the film pack.
[0058] In contrast, if the liquid flows into the film pack 160
through the communication hole 162a of the connecting member 162,
as shown in FIG. 4C, the film pack 160 expands (volume increases)
as the pair of films 164 are separated from each other. Thus, the
liquid can be contained in the film pack. Additionally, if the
liquid within 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 contracts (volume
decreases). In this way, since the film pack 160 is easily
deformable according to the amount of the liquid to be contained
therein, the pressure of the liquid inside the film pack can be
maintained in a predetermined range.
[0059] The structure of the film 164 used for the film pack 160 is
illustrated in FIG. 4D. The shown film 164 has a multilayer
structure, and adopts a structure in which polypropylene (PP)
layers having excellent water-proofing characteristics are stuck on
both sides of aluminum foil (AL) and polyethylene terephthalate
(PET) layers having excellent shock resistance are further stuck on
both sides from on the polyprolylene layers. The respective layers
are pasted together by an adhesive. By providing a middle layer of
aluminum foil, the strength of the film can be enhanced and gas
barrier properties can also be enhanced. The film pack 160 of such
a configuration has excellent heat resistance, has handleability at
a high temperature (for example, 150.degree. C.), has flexibility,
and is easily deformed. Since the deformation of the film pack 160
is easy, even if there is a case that covers the circulating pump
110, the film pack can be deformed within the case. As a result,
since the shape of the case is not easily restricted, the case that
covers the circulating pump 110 can be made small. Additionally,
weight reduction can be realized, and the film pack 160 can be
simply formed by thermocompression bonding, which is economical.
Moreover, since the film pack 160 is attachable to and detachable
from the liquid chamber 146, it is easy to replace the film pack
160, which is economical.
[0060] The structure of the film 164 used for the film pack 160 is
not limited to the structure shown in FIG. 4D. For example, instead
of the aluminum foil as the middle layer, ethylene-vinyl alcohol
copolymer resin (EVOH), polyvinylidene chloride (PVDC), or the like
may be used. Additionally, a transparent film, obtained by directly
sticking the outer layer of polyamide (nylon) and the inner layer
of polypropylene (PP) together with an adhesive, may be used. By
making a part or the whole of the film pack 160 transparent, it is
possible to visually recognize the inside of the film pack 160 (the
amount of the liquid and flow of the liquid).
A4. Pressure Regulation liquid BF:
[0061] Next, the pressure regulation liquid BF will be described.
The pressure regulation liquid BF is supplied from the film pack
160 to the liquid chamber 146 as a part of the liquid that
circulates, in order to maintain the inside of the liquid channel
190 at an appropriate pressure, when the circulating pump 110 is
brought into the operating state from the stopped state. In the
present example, the phrase "maintaining the inside of the liquid
channel 190 at an appropriate pressure" means maintaining the
pressure inside the liquid channel 190 (hereinafter referred to as
an internal pressure) at the atmospheric pressure or higher in the
operating state of the circulating pump 110. As the internal
pressure of the liquid channel 190 is maintained at the atmospheric
pressure or higher by the pressure regulation liquid BF, a
situation in which the liquid channel 190 is deformed inward due to
the force of the atmospheric pressure and the channel becomes
narrow is avoided. As a result, in the circulating pump 110, a
decrease in the circulation efficiency of the liquid that
circulates is avoided by the pressure regulation liquid BF.
[0062] The principle in which the internal pressure of the liquid
channel 190 is appropriately maintained as the pressure regulation
liquid BF is supplied to the liquid chamber 146 will be described.
FIG. 5 is an explanatory view schematically illustrating the
distribution of the internal pressure and a shape in the liquid
channel 190 where the internal pressure is appropriately
maintained.
[0063] A model (internal pressure investigation model) of the
liquid circulating device 100 for investigating the internal
pressure of the liquid channel 190 is shown in an upper portion of
FIG. 5. As shown in this drawing, in the internal pressure
investigation model, the liquid channel 190 is shown on a straight
line in order to facilitate investigation. Additionally, an end
point of the liquid channel 190 connected to the pump discharge
channel 142 is defined as a channel start point S, and an endpoint
that is used as the pump suction channel 144 is defined as a
channel end point E. Moreover, the length of the liquid channel 190
from the channel start point S to the channel end point E is
defined as L. In addition, although the channel end point E and the
pump suction channel 144 are shown in FIG. 5 so as to be separated,
the channel end point E and the pump suction channel 144 are
connected in the actual liquid circulating device 100. The arrow of
a broken line shown in the drawing indicates the direction in which
the liquid flows. Additionally, the internal pressure of the
channel start point S in the operating state of the circulating
pump 110 is defined as pressure Pout, and the internal pressure of
the channel end point E in the operating state of the circulating
pump 110 is defined as Pin.
[0064] The circulating pump 110 pressurizes the liquid that has
flowed into the pump chamber 130 from the pump suction channel 144,
and pumps the liquid toward the liquid channel 190 from the pump
discharge channel 142. Then, a pressure gradient is formed in the
internal pressure of the liquid channel 190 by the pumping of the
liquid using the circulating pump 110, and the liquid flows
depending on the formed pressure gradient. In the internal pressure
investigation model, the pump chamber 130 applies the pressure of
.DELTA.Ps further by driving of the piezoelectric element 114 to
the liquid that has flowed into the pump chamber 130 with the
internal pressure Pin. Accordingly, the relationship of
Pin+.DELTA.Ps=Pout is established in the internal pressure
investigation model. In the present example, the internal pressure
of the liquid channel 190 is investigated using such an internal
pressure investigation model.
[0065] An internal pressure distribution model of the liquid
channel 190 in a state where the internal pressure is appropriate
is shown in a middle portion of FIG. 5. In the internal pressure
distribution model, the horizontal axis is defined as the position
x from the channel start point S in the liquid channel 190, and the
vertical axis is defined as the internal pressure P(x) at the
position x. As described above, in the present example, the state
where the internal pressure is appropriate means that the internal
pressure is equal to or higher than the atmospheric pressure.
Accordingly in the internal pressure distribution model in the
present example, the internal pressure Pin in the channel end point
E (x=L) where the internal pressure becomes the lowest is defined
as the atmospheric pressure. In FIG. 5, the pressure is expressed
as the relative atmospheric pressure (on the basis of the
atmospheric pressure). In this case, if the relationship of
Pin+.DELTA.Ps=Pout described above is taken into consideration, the
internal pressure in the channel start point S becomes Pout=Ps.
[0066] Additionally, in the present example, the pressure gradient
in the liquid channel 190 adopts a linear model. Accordingly, the
relationship between P(x) and the position x can be expressed by
the following Formula (5). Such an internal pressure distribution
model is adopted in the present example. Additionally, in the
present example, although P(x) is linear, P(x) has a decay curve or
a quadratic curve.
P ( x ) = - Ps L x + Ps ( 5 ) ##EQU00002##
[0067] A shape schematic view of the liquid channel 190 in a state
where the internal pressure is appropriate is shown in a lower
portion of FIG. 5. That is, the shape of the liquid channel 190 in
a case where the internal pressure is distributed like P(x) shown
in the middle portion of FIG. 5 is schematically shown. As shown in
the drawing, the shape of the liquid channel 190 before the
internal pressure changes (stopped state) is shown by a broken
line, and a portion where the shape of the liquid channel 190 has
changed depending on a change in the internal pressure caused by
the operation of the circulating pump 110 is shown by a slanting
line. In addition, the internal pressure in the stopped state is
almost uniformly the atmospheric pressure. 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 channel 190 is distorted toward the outside
due to an outward force caused by a pressure differential. That is,
in a case where the internal pressure changes as shown in the
middle portion of FIG. 5, the liquid channel 190 expands and the
volume inside the liquid channel 190 becomes large. If Young's
modulus of the tube that constitutes the liquid channel 190 is
uniform without depending on the position x, the outward distortion
amount of the liquid channel 190 at each position x of the liquid
channel 190 becomes a value according to the magnitude of the
internal pressure P(x) at each position x. Since the internal
pressure is linear with respect to the position x of the liquid
channel 190, the distortion amount of the liquid channel 190 also
becomes linear with respect to the position x.
[0068] Here, the relationship of the following Formula (6) is
established if the ratio of the internal pressure P(x) of the
liquid channel 190 and the increased amount of the cross-sectional
area of the channel is defined as Se, and the amount of volume
change of the liquid channel 190 per minute length .DELTA.x is
defined as .DELTA.Ve(x), when the internal pressure has changed
from a state (stopped state of the circulating pump 110) where the
internal pressure is uniformly the atmospheric pressure to a state
(operating state of the circulating pump 110) of the internal
pressure distribution shown in FIG. 5. In addition, Se is a
constant that is determined depending on Young's modulus, Poisson's
ratio, internal diameter, and external diameter of the tube that
constitutes the liquid channel 190, and is constant irrespective of
the position x of the channel.
.DELTA.Ve(x)=SeP(x)dx (6)
[0069] Accordingly, if the amount of volume change in the total
(length L) of the liquid channel 190 is defined as .DELTA.Vs,
.DELTA.Vs is expressed as the following Formula (7).
.DELTA.Vs=.intg..sub.0.sup.L.DELTA.Ve(x)=.intg..sub.0.sup.LSeP(x)dx
(7)
[0070] Moreover, if the compliance of the liquid channel 190 is
defined as Cs, since the compliance Cs is the ratio of the internal
pressure and the increased amount of the internal volume when the
internal pressure is uniformly applied to the liquid channel 190,
the compliance is expressed by multiplying Se by the tube length L.
Accordingly, since the relationship of the following Formula (8) is
established, Formula (7) can be expressed as the following Formula
(9).
Cs = L Se ( 8 ) .DELTA. Vs = 1 L .intg. 0 L Cs P ( x ) x ( 9 )
##EQU00003##
[0071] Additionally, if Formula (5) is applied as the internal
pressure P(x), Formula (9) is expressed as the following Formula
(10).
.DELTA. Vs = 1 L .intg. 0 L Cs ( - Ps L x + Ps ) x = 1 2 Cs Ps ( 10
) ##EQU00004##
[0072] That is, by further supplying the liquid of .DELTA.Vs
(=1/2CsPs) to the liquid channel 190 compared to the stopped state,
the inside of the liquid channel can be maintained at an
appropriate pressure and the circulating pump 110 can be operated.
In the present example, the pressure regulation liquid BF that is
contained in advance in the film pack 160 is used as a liquid
corresponding to the amount of volume change .DELTA.Vs of the
liquid channel 190. Specifically, the pressure regulation liquid BF
is contained in the film pack 160 in the stopped state of the
circulating pump 110, and the pressure regulation liquid BF is
supplied to the liquid chamber 146 in the operating state of the
circulating pump 110.
[0073] A value that satisfies the following Formula (11) is applied
as the volume Vb of the pressure regulation liquid BF to be
contained in the film pack 160 in the stopped state of the
circulating pump 110. In addition, in Formula (11), .gamma. is a
coefficient. The coefficient .gamma. is set to 0.8 or less in
consideration of the fact that the circulating pump 110 operates
even in a case where the volume Vb of the pressure regulation
liquid BF to be contained in the film pack 160 is slightly smaller
than the amount of volume change .DELTA.Vs of the liquid channel
190.
Vb=.gamma..DELTA.Vs
(.gamma..gtoreq.0.8) (11)
[0074] The pressure regulation liquid BF with the volume Vb
contained in the film pack 160 is automatically supplied into the
pump chamber 130 by the atmospheric pressure applied to the film
pack 160, if the circulating pump 110 starts to operate.
Specifically, this is based on the following principle.
[0075] If the operation of the circulating pump 110 is started, a
pressure gradient is formed in the internal pressure of the liquid
channel 190. The pressure gradient of the internal pressure deforms
the liquid channel 190. In that case, the internal pressure (Pout)
of the channel start point S in the liquid channel 190 increases
due to the pressurization of .DELTA.Ps by the circulating pump 110.
As a result, the liquid channel 190 in the vicinity of the channel
start point S expands. If the channel start point S of the liquid
channel 190 expands, since the liquid moves in a direction in which
the volume of the liquid that has expanded is compensated for, the
volume of the liquid in the vicinity of the channel end point E
becomes less, and the internal pressure in the vicinity of the
channel end point E decreases. In that case, the pressure
regulation liquid BF is supplied to the liquid chamber 146 from the
film pack 160 due to the pressure differential between the vicinity
of the channel endpoint E and the inside of the film pack 160.
Then, the amount of volume change .DELTA.Vs of the liquid channel
190 is compensated for by the pressure regulation liquid BF of the
volume Vb supplied, and the internal pressure of the liquid channel
190 is maintained in an appropriate state. Additionally, if the
volume Vb of the pressure regulation liquid BF to be contained in
the film pack 160 is insufficient, channel deformation in the
direction of the inside of the liquid channel 190 is caused by the
atmospheric pressure. However, in a range (0.8.ltoreq..gamma.<1)
slightly smaller than the amount of volume change .DELTA.Vs of the
liquid channel 190, the channel deformation to the direction of
inside of the liquid channel 190 by the atmospheric pressure does
not become a large resistance element even if the deformation is
caused more or less. Therefore, the circulation efficiency of the
liquid by the circulating pump 110 does not decrease
significantly.
[0076] As described above, the liquid circulating device 100
contains the pressure regulation liquid BF in the film pack 160 in
advance in the stopped state of the circulating pump 110. Then,
when the circulating pump 110 operates, the pressure regulation
liquid BF is supplied to the liquid chamber 146 from the film pack
160, and the pressure regulation liquid BF compensates for the
amount of volume change .DELTA.Vs of the liquid channel 190.
Accordingly, during the operation of the circulating pump 110, the
pressure regulation liquid BF keeps the internal pressure of the
liquid channel 190 from becoming significantly lower than the
atmospheric pressure, and the channel deformation in the direction
of the inside of the liquid channel 190 by the atmospheric pressure
is avoided. As a result, in the liquid circulating device 100, the
channel cross-sectional area of the liquid in the liquid channel
190 can be sufficiently secured, and a decrease in the circulation
efficiency can be prevented. Additionally, since the pressure
regulation liquid BF contained in the film pack 160 is
automatically supplied to the liquid chamber 146 by the pressure
differential between the internal pressure in the vicinity of the
channel endpoint E and the atmospheric pressure applied to the film
pack 160, it is not necessary to control the supply of the pressure
regulation liquid BF separately using a pressure sensor or the
like.
[0077] Additionally, if the liquid circulating device 100 is not
equipped with the film pack 160, it is better to replenish the
liquid channel 190 with the liquid of the volume Vb in the stopped
state of the circulating pump 110 and keep the internal pressure
from becoming equal to or higher than the atmospheric pressure in
the stopped state, in order to maintain the internal pressure in an
appropriate state in the operating state. In this case, since the
liquid channel 190 has a state where the liquid channel has
expanded from a normal shape as a steady state in the stopped
state, and consequently, load is added to the liquid channel 190,
the durability of the whole liquid channel 190 (particularly, in
the vicinity of the channel end point E) decreases. In the liquid
circulating device 100 in the present example, the pressure
regulation liquid BF is contained in the film pack 160 in the
stopped state of the circulating pump 110. Thus, the internal
pressure can be maintained at the atmospheric pressure in the
liquid channel 190 in the stopped state of the circulating pump
110, and application of unnecessary load to the liquid channel 190
due to the internal pressure can be avoided. Thus, the durability
particularly in the vicinity of the channel end point E
improves.
B. Second Example
[0078] Next, a second example of the invention will be described.
In a second example, as the liquid circulating device, a liquid
circulating device 200 is used instead of the liquid circulating
device 100. In the liquid circulating device 100 in the first
example, the pressure regulation liquid BF is contained in the film
pack 160. However, in the liquid circulating device 200 in the
second example, instead of the film pack 160, the pressure
regulation liquid BF is contained in a branch channel 210 provided
in the liquid channel 190. Since components other than the branch
channel 210 are the same as those of the first example, description
of the components other than the branch channel 210 is omitted. In
addition, the same reference numerals are given to the same
components in the first example and the second example.
[0079] FIG. 6 is an explanatory view illustrating the configuration
of the branch channel 210 in the present example. The branch
channel 210 is provided at the position of the liquid channel 190
near the pump suction channel 144. The branch channel 210 has high
gas barrier properties, and is made of such materials that the
liquid therein does not volatilize easily. The liquid that
circulate through the liquid channel 190 by the operation of the
circulating pump 110, including the pressure regulation liquid BF,
is contained within the branch channel 210. Hereinafter, the liquid
that circulates through the circulating pump 110 and the liquid
channel 190 is also referred to as a first liquid Lq1.
[0080] The branch channel 210 is installed so that the position of
the liquid head of the first liquid Lq1 becomes a position higher
than the circulating pump 110. The first liquid Lq1 of the volume
Vb is contained within the branch channel 210, and functions as the
pressure regulation liquid BF in the operating state of the
circulating pump 110.
[0081] As shown in the drawing, the branch channel 210 has therein
a movable portion 216. The branch channel 210 has a vent hole 218
as an air flow passage, and is configured so that the movable
portion 216 is in contact with the open air. The movable portion
216 is constituted by 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. If the position of the liquid
head of the first liquid Lq1 moves, the movable portion 216 moves
in a height direction of the branch channel 210 where the movable
portion is in contact with the first liquid Lq1. The inner wall
surface of the branch channel 210 has a smooth surface so that the
movement of the movable portion 216 is smooth. Additionally, the
liquid circulating device 200 is equipped with a sensor 230 that
can measure the travel distance of the movable portion 216, in the
vicinity of the branch channel 210, and can measure the travel
distance of the movable portion 216.
[0082] The high-viscosity gel liquid 214 that is a constituent
element of the movable portion 216 is enclosed as a sealing
material for preventing leakage of the first liquid Lq1 from the
branch channel 210, and preventing evaporation. The high-viscosity
gel liquid 214 has polybutene of an average molecular weight of 630
as a base material, and has visco-elasticity and transparency. As
for the type of high-viscosity gel liquid 214, polybutene,
.alpha.-olefin, or the like of an average molecular weight of 300
to 3700 can be used.
[0083] Additionally, it is desirable that the high-viscosity gel
liquid 214 not be substantially compatible with the first liquid
Lq1. In a case where an oily medium is used as the first liquid
Lq1, an aqueous high-viscosity gel that contains water as a medium
can be used. In a case where the aqueous high-viscosity gel liquid
214 is used, an oily layer that contains an organic solvent as a
solvent may be further formed on the high-viscosity gel liquid 214
to prevent permeation and drying in a case where the gas
permeability of the high-viscosity gel liquid 214 is high or in a
case where the gel liquid is apt to be dried.
[0084] The second liquid Lq2 is contained in the branch channel 210
in order to prevent the high-viscosity gel liquid 214 from
dissolving in the first liquid Lq1. The second liquid Lq2 is a
liquid with a greater vaporization heat than the first liquid Lq1,
and is a liquid that is phase-separable from the first liquid Lq1.
Additionally, the second liquid Lq2 has a density smaller than the
first liquid Lq1. In the present example, fluidized paraffin is
used as the second liquid Lq2. In addition, calcium alginate can
also be used as the second liquid Lq2. As the movable portion 216
has the above configuration, the first liquid Lq1 does not come
into direct contact with the atmospheric air.
[0085] In the liquid circulating device 200 of the configuration
described above, if the circulating pump 110 operates, a pressure
gradient is formed in the internal pressure of the liquid channel
190 as described in the first example. Then, the pressure in the
vicinity of the channel endpoint E of the liquid channel 190
decreases due to a change in the volume of the liquid channel 190.
The first liquid Lq1 (equivalent to the pressure regulation liquid
BF) within the branch channel 210 is supplied to the liquid channel
190 by the pressure differential between the internal pressure in
the vicinity of the channel end point E and the atmospheric
pressure applied to the branch channel 210. As a result, the
internal pressure of the liquid channel 190 can be kept equal to or
higher than the atmospheric pressure, and the circulating pump 110
can operate with the internal pressure in an appropriate state.
[0086] As described above, the liquid circulating device 200
includes the branch channel 210 that stores the first liquid Lq1 as
the pressure regulation liquid BF. Thus, similarly to the first
example, in the operating state of the circulating pump 110, the
internal pressure of the liquid channel 190 can be kept from
becoming significantly lower than the atmospheric pressure, and the
liquid circulating device can operate in an appropriate state.
Additionally, since the branch channel 210 is equipped with the
movable portion 216, the first liquid Lq1 can be prevented from
leaking to the outside from the branch channel, and the first
liquid Lq1 can be prevented from evaporating.
[0087] Additionally, since the liquid circulating device 200 is
equipped with the sensor 230, the liquid circulating device can
measure the travel distance of the movable portion 216 when the
circulating pump 110 changes from the stopped state to the
operating state. Also, it is possible to acquire the amount of the
first liquid Lq1 supplied to the liquid channel 190 as the pressure
regulation liquid BF on the basis of the measured travel distance
of the movable portion 216. Since the supply amount of the pressure
regulation liquid BF is equal to the amount of volume change of the
liquid channel 190, it is consequently possible to acquire the
state of the internal pressure of the liquid channel 190 in the
operating state in real time.
C. Modification Examples
[0088] The invention is not limited to the above examples or
embodiments, and can be carried out in various aspects without
departing from the scope of the invention. For example, the
following modifications can also be made.
C1. Modification Example 1
[0089] In the above examples, the liquid circulating device 100 is
utilized for cooling the piezoelectric actuator 34 of the liquid
ejecting apparatus 20 (water jet knife). However, the liquid
circulating device 100 may be utilized for adjusting the
temperature of other medical apparatuses other than the water jet
knife. For example, the liquid circulating device 100 may be
utilized for adjusting the temperature of a motor section of a
medical drill, an ultrasonic wave generating section of an
ultrasonic scaler that removes plaque with an ultrasonic wave, or
the like, or may be an ejecting apparatus that ejects a medical
fluid to a living body. Additionally, the liquid circulating device
100 may be used not only when cooling a heat generator but when
heating an object. For example, the liquid circulating device may
be used when heating or keeping warm a part of a human body. This
can be realized by separately equipping the above liquid
circulating device 100 with a heating section that heats a
circulation liquid. Particularly, since the liquid circulating
device 100 ensures the stable circulation efficiency in medical
apparatuses in which safety is regarded as important, the liquid
circulating device can be applied to the medical apparatuses.
C2. Modification Example 2
[0090] In the above examples, a liquid, particularly water, is
adopted as the liquid that circulates through the liquid
circulating device 100. However, the liquid is not limited to this,
and various liquids can be adopted. For example, nitrogen or carbon
dioxide may be adopted as gas. Additionally, oil, other than water
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 Example 3
[0091] In the above examples, the film pack is adopted as the
liquid containing chamber. However, the liquid containing chamber
is not limited to this. For example, a liquid containing chamber
including a housing that has a diaphragm may be adopted. In
addition, a liquid containing chamber, which is deformable
according to the amount of a liquid to be contained, such as an
elastic bag-shaped rubber pack or bellows, may be adopted. Even if
such a liquid containing chamber is adopted, the same effects as
the above examples can be obtained.
C4. Modification Example 4
[0092] In the second example, the branch channel 210 is equipped
with the movable portion 216. However, a branch channel that is not
equipped with the movable portion may be adopted. This can simplify
the configuration of the branch channel.
C5. Modification Example 5
[0093] In the above examples, the piezoelectric element is adopted
as an operating element. However, the operating element is not
limited to this, and various elements may be adopted. For example,
drive elements, such as an electrostrictive element, an
electromagnetic actuator, an electrostatic actuator, and a
dielectric poly-actuator, can be used. Even if these drive elements
are adopted, the same effects as the above examples can be
obtained. Additionally, in the above examples, a laminated
piezoelectric element is adopted as the piezoelectric element. In
addition, however, a piezoelectric element that is a crystal single
body, a mono-morph piezoelectric element, or a bimorph
piezoelectric element may be adopted.
C6. Modification Example 6
[0094] In the above examples, the check valve 148 is adopted as a
liquid resistance element. However, the liquid resistance element
is not limited to this, and various liquid resistance elements may
be adopted. FIGS. 7A to 7C are explanatory views showing liquid
resistance elements that can be adopted. The shown liquid
resistance element (A) is a check valve installed at a position
different from the first example. A liquid resistance element (B)
suppresses the flow of the liquid from the pump chamber 130 to the
liquid chamber 146, without using the check valve. A liquid
resistance element (C) has a configuration in which the check valve
148 is not installed in the above examples. Even in the liquid
resistance element (C), the flow of the liquid from the pump
chamber 130 to the liquid chamber 146 can be suppressed depending
on the shape of the liquid resistance element. Additionally, since
the liquid resistance element (B) and the liquid resistance element
(C) do not have the movable portion such as the check valve 148,
durability can be improved.
[0095] This application claims priority to Japanese Patent
Application No. 2012-059234 filed on Mar. 15, 2012, and Application
No. 2012-249060 filed on Nov. 13, 2012, the entirety of which is
hereby incorporated by reference.
* * * * *