U.S. patent application number 12/548019 was filed with the patent office on 2010-03-04 for pulsation generating mechanism, connecting flow channel tube, and fluid ejecting apparatus.
This patent application is currently assigned to SEIKO EPSON CORPORATION. Invention is credited to Kazuo KAWASUMI, Hideki KOJIMA, Yasuhiro ONO, Takeshi SETO.
Application Number | 20100054960 12/548019 |
Document ID | / |
Family ID | 41725733 |
Filed Date | 2010-03-04 |
United States Patent
Application |
20100054960 |
Kind Code |
A1 |
SETO; Takeshi ; et
al. |
March 4, 2010 |
PULSATION GENERATING MECHANISM, CONNECTING FLOW CHANNEL TUBE, AND
FLUID EJECTING APPARATUS
Abstract
A fluid ejecting apparatus having a fluid chamber, an inlet flow
channel, and a nozzle configured to eject fluid supplied from the
inlet flow channel to the fluid chamber from the nozzle in a pulsed
manner by changing the volume of the fluid chamber includes: a
diaphragm; a wall surface provided so as to oppose the diaphragm; a
spacer being provided between the diaphragm and the wall surface
and having a cylindrical through hole; a piezoelectric element
configured to displace the diaphragm; and a connecting flow channel
tube communicated with the fluid chamber, wherein the nozzle is
provided at an end of the connecting flow channel tube opposite to
the fluid chamber, the fluid chamber is defined by the diaphragm,
the wall surface, and an inner surface of the through hole of the
spacer, and the inlet flow channel is defined by a groove provided
on the wall surface and the spacer and is communicated with the
fluid chamber.
Inventors: |
SETO; Takeshi; (Chofu-shi,
JP) ; KAWASUMI; Kazuo; (Chino-shi, JP) ;
KOJIMA; Hideki; (Matsumoto-shi, JP) ; ONO;
Yasuhiro; (Matsumoto-shi, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 320850
ALEXANDRIA
VA
22320-4850
US
|
Assignee: |
SEIKO EPSON CORPORATION
Tokyo
JP
|
Family ID: |
41725733 |
Appl. No.: |
12/548019 |
Filed: |
August 26, 2009 |
Current U.S.
Class: |
417/53 ;
417/413.2 |
Current CPC
Class: |
A61B 17/3203 20130101;
A61B 2017/00154 20130101 |
Class at
Publication: |
417/53 ;
417/413.2 |
International
Class: |
F04B 43/04 20060101
F04B043/04 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 27, 2008 |
JP |
2008-217671 |
Claims
1. A fluid ejecting apparatus comprising: a diaphragm; a wall
surface provided so as to oppose the diaphragm; a spacer being
provided between the diaphragm and the wall surface and having a
cylindrical through hole; a piezoelectric element configured to
displace the diaphragm; a fluid chamber defined by the diaphragm,
the wall surface, and an inner surface of the through hole of the
spacer; a connecting flow channel tube communicated with the fluid
chamber; an inlet flow channel defined by a groove provided on the
wall surface and the spacer, and in communication with the fluid
chamber; and a nozzle provided at an end of the connecting flow
channel tube opposite to the fluid chamber that is configured to
eject fluid from the fluid chamber in a pulsed manner by changing
the volume of the fluid chamber.
2. The fluid ejecting apparatus according to claim 1, the groove of
the wall surface including: a first end portion provided with a
hole through which the fluid is supplied into the groove of the
wall surface, a first middle portion extending from the first end
portion in an arcuate shape along the wall surface, a second middle
portion extending from the first middle portion to the inner
surface of the spacer along a direction of a line tangent to the
inner surface of the spacer, and a second end portion extending
from the second middle portion along an edge of the inner surface
of the spacer.
3. The fluid ejecting apparatus according to claim 2, is the second
end portion being formed into an inclined surface continuing from a
bottom surface of the groove on the wall surface which defines the
inlet flow channel to the wall surface.
4. The fluid ejecting apparatus according to claim 1, the fluid
chamber being formed with a coating layer on an inner wall surface
thereof.
5. The fluid ejecting apparatus according to claim 1, the fluid
ejecting apparatus including a holding portion configured to hold a
peripheral edge portion of the diaphragm, and the piezoelectric
element being disposed in the interior of the holding portion and
resin being filled in a space between the piezoelectric element and
the holding portion.
6. The fluid ejecting apparatus according to claim 5, the resin
having thermal conductivity.
7. The fluid ejecting apparatus according to claim 1, a connecting
portion between the inner wall of the connecting flow channel tube
and the inner wall of the fluid chamber having a substantially
arcuate shape.
8. The fluid ejecting apparatus according to claim 1, the nozzle
being inserted into the connecting flow channel tube and an
adhesive groove being provided along a joint surface of the nozzle
with respect to the connecting flow channel tube.
9. The fluid ejecting apparatus according to claim 1, the
connecting flow channel tube being detachably attached.
10. A pulsation generating mechanism comprising: a diaphragm; a
wall surface provided so as to oppose the diaphragm; a spacer being
provided between the diaphragm and the wall surface and having a
cylindrical through hole; a piezoelectric element configured to
displace the diaphragm; a fluid chamber defined by the diaphragm,
the wall surface, and an inner surface of the through hole of the
spacer; and an inlet flow channel defined by a groove provided on
the wall surface and the spacer that is in communication with the
fluid chamber, the fluid ejecting apparatus being configured to
discharge fluid supplied from the inlet flow channel to the fluid
chamber in a pulsed manner from a flow channel that is in
communication with the fluid chamber by changing the volume of the
fluid chamber.
11. A connecting flow channel tube which is detachably attached to
a pulsation generating mechanism configured to discharge fluid from
an outlet flow channel in a pulsed manner by changing the volume of
a fluid chamber that is in communication with the outlet flow
channel, the connection flow channel tube comprising: a first end
configured to be communicatable with the outlet flow channel; and a
second end opposite to the first end and having a fluid ejecting
opening with a smaller cross-sectional area in the vertical
direction with respect to a direction of flow of the fluid than a
cross-sectional area of the outlet flow channel.
12. A fluid ejecting apparatus comprising: a fluid chamber; an
inlet flow channel that supplies fluid to the fluid chamber; and an
outlet flow channel in communication with the fluid chamber, the
outlet flow channel having an inertance less than an inertance of
the inlet flow channel, the fluid ejecting apparatus ejecting the
fluid supplied to the fluid chamber from the outlet flow channel by
changing a volume of the fluid chamber.
13. The fluid ejecting apparatus according to claim 12, the inlet
flow channel being formed to supply the fluid to the fluid chamber
so as to create a whirling flow of the fluid within the fluid
chamber.
14. The fluid ejecting apparatus according to claim 13, the inlet
flow channel including: a first end portion provided with a hole
through which the fluid is supplied to the inlet flow channel, a
first middle portion extending from the first end portion in an
arcuate shape around an outside of the fluid chamber, a second
middle portion extending from the first middle portion to an inner
surface of the fluid chamber along a direction of a line tangent to
the inner surface of the fluid chamber, and a second end portion
extending from the second middle portion along the inner surface of
the fluid chamber.
15. The fluid ejecting apparatus according to claim 12, further
comprising: an outlet flow channel tube including the outlet flow
channel and an outlet connecting flow channel in communication with
the outlet flow channel; and a nozzle in communication with the
outlet flow channel tube, a fluid ejection opening of the nozzle
having a diameter smaller than a diameter of the output flow
channel.
16. A method for ejecting fluid comprising: supplying fluid from an
inlet flow channel to a fluid chamber at a constant pressure; and
changing a volume of the fluid chamber to eject the fluid from the
fluid chamber and through an outlet flow channel having an
inertance less than an inertance of the inlet flow channel.
17. The method for ejecting fluid according to claim 16, the fluid
being supplied to the fluid chamber so as to create a whirling flow
of the fluid within the fluid chamber.
Description
[0001] This application claims priority to Japanese Application No.
2008-217671 filed in Japan on Aug. 27, 2008, the disclosure of
which is hereby incorporated by reference in its entirety.
BACKGROUND
[0002] 1. Technical Field
[0003] The present invention relates to a pulsation generating
mechanism configured to discharge fluid with pulsation, a
connecting flow channel tube to be inserted into the pulsation
generating mechanism, and a fluid ejecting apparatus having the
same and being configured to eject the fluid in a pulsed
manner.
[0004] 2. Related Art
[0005] Operation with ejected fluid enables incision of organ
substances while maintaining vasculature such as blood vessels and,
in addition, an incidental damage applied to anatomy other than the
portion to be incised is small and hence a burden applied to a
patient is small. Furthermore, since the amount of bleeding is
small, visibility of an operation field is not hindered by blood,
and hence quick operation is enabled, so that this technology is
applied to many clinical surgeries specifically such as hepatic
resection which causes medical personnel hardship due to the
bleeding from small blood vessels.
[0006] As a fluid ejecting apparatus configured to incise or remove
anatomy, a fluid ejecting apparatus including a pulsation
generating mechanism configured to reduce the volume of a fluid
chamber to discharge fluid and a connecting flow channel tube
having a nozzle connected at one end thereof to an outlet flow
channel of the pulsation generating mechanism and being reduced in
diameter at the other end thereof to a diameter smaller than that
of the outlet flow channel is known (for example, see
JP-A-2005-152127).
[0007] According to a fluid ejecting apparatus disclosed in
JP-A-2005-152127 described above, since a pumping action is
performed by the fluid ejecting apparatus by itself, a priming
action and an elimination of air bubbles in a pump chamber are
needed at the time of activation from its driving
characteristics.
[0008] The fluid (liquid) includes gas (air) although the quantity
is not much. When the gas exists in the liquid, the gas gradually
gets together to form air bubbles and stays therein. When the air
bubbles stay in the fluid chamber, the internal pressure cannot
rise sufficiently when the volume is reduced, so that a pulsation
discharge might not be achieved.
SUMMARY
[0009] An advantage of some aspects of the invention is to solve at
least a part of the problem mentioned above and the invention can
be embodied in the following aspects or application examples.
APPLICATION EXAMPLE 1
[0010] Application example 1 is directed to a fluid ejecting
apparatus having a fluid chamber, an inlet flow channel, and a
nozzle configured to eject fluid supplied from the inlet flow
channel to the fluid chamber from the nozzle in a pulsed manner by
changing the volume of the fluid chamber including: a diaphragm; a
wall surface provided so as to oppose the diaphragm; a spacer being
provided between the diaphragm and the wall surface and having a
cylindrical through hole; a piezoelectric element configured to
displace the diaphragm; and a connecting flow channel tube
communicated with the fluid chamber, in which the nozzle is
provided at an end of the connecting flow channel tube opposite to
the fluid chamber, the fluid chamber is defined by the diaphragm,
the wall surface, and an inner surface of the through hole of the
spacer, and the inlet flow channel is defined by a groove provided
on the wall surface and the spacer and is communicated with the
fluid chamber.
[0011] In this configuration, the inlet flow channel is formed with
an arcuate shaped inlet flow channel on the wall surface which
constitutes part of the fluid chamber. Therefore, an inertance on
the inlet flow channel side of the fluid chamber may be set to a
value sufficiently larger than an inertance on an outlet flow
channel side of the fluid chamber from both facts that a long flow
channel length of the inlet flow channel is secured, and that the
cross-sectional area in the vertical direction with respect to the
direction of flow of the fluid can be set to be small. In this
configuration, a simple structure in which a check valve is not
provided is realized.
[0012] Consequently, an operation to supply the fluid from the
inlet flow channel into the fluid chamber at a constant pressure,
and convert the same to a strong pulsation by changing the volume
of the fluid chamber by the diaphragm is enabled. Therefore, a
priming action is no longer necessary and, since an inflow of the
fluid is continued even though air bubbles are generated, they are
discharged in a certain time period and hence the normal operation
may be restored.
APPLICATION EXAMPLE 2
[0013] Preferably, the groove on the wall surface includes a first
end portion provided with a hole through which the fluid is
supplied into the groove of the wall surface, is formed to extend
from the first end portion in an arcuate shape along the wall
surface, is formed to extend from the opposite side of the portion
formed into the arcuate shape to the first end portion to the inner
surface of the spacer along a direction of a tangent line of the
inner surface of the spacer, and is formed from the opposite side
of the portion formed along a direction of a tangent line of the
inner surface of the spacer opposite to the arcuate portion along
an edge of the inner surface of the spacer.
[0014] In this configuration, the fluid is caused to flow along the
inner surface of the through hole of the spacer (that is, the inner
peripheral surface of the fluid chamber), so that a whirling flow
is generated in the fluid chamber.
[0015] By causing the fluid to whirl, the fluid is directed outward
from the fluid chamber by a centrifugal force, and the air bubbles
get together at the center portion and is discharged to the outside
in association with discharge of the fluid through the connecting
flow channel tube. Therefore, the air bubbles are prevented from
staying in the fluid chamber, and the pressure in the interior of
the fluid chamber may be increased sufficiently, so that a reliable
pulsation discharge is achieved.
APPLICATION EXAMPLE 3
[0016] Preferably, a terminal end portion of the groove on the wall
surface formed along the edge of the inner surface of the spacer is
formed into an inclined surface continuing from a bottom surface of
the groove on the wall surface which defines the inlet flow channel
to the wall surface.
[0017] In this configuration, since the inlet flow channel is
communicated with the fluid chamber continuously from the bottom
surface of the groove which constitutes the inlet flow channel to
the wall surface by the inclined surface, a fluid resistance at a
connecting portion between the inlet flow channel and the wall
surface is reduced, and also turbulence of the whirling flow and
generation of the air bubbles due to a vortex flow generated by
sudden change of the flow channel is restrained.
APPLICATION EXAMPLE 4
[0018] Preferably, the fluid chamber is formed with a coating layer
on an inner wall surface thereof
[0019] Here, as the coating layer, for example, a membrane layer
formed by plating may be employed.
[0020] Gas contained in liquid generates from the fluid when the
pressure in the fluid chamber is reduced. The air bubbles get
together to the center of the fluid chamber by the whirling flow.
However, when small gaps or corners of components exist, the air
bubbles might be adhered to these points and hence might not be
discharged.
[0021] Therefore, by coating the small gaps or joint corners to
form a continuous surface by forming the continuous coating layer
in the interior of the fluid chamber, generation of the air bubbles
is restrained.
APPLICATION EXAMPLE 5
[0022] Preferably, the fluid ejecting apparatus includes a holding
portion configured to hold a peripheral edge portion of the
diaphragm, and the piezoelectric element is disposed in the
interior of the holding portion and resin is filled in a space
between the piezoelectric element and the holding portion.
[0023] In this configuration, by coating the periphery of the
piezoelectric element with the resin, inter-electrode short circuit
due to attachment of water content to the piezoelectric element is
prevented. Therefore, the resin to be filled preferably has low
water absorbability.
APPLICATION EXAMPLE 6
[0024] Preferably, the resin has thermal conductivity.
[0025] When the fluid ejecting apparatus in this application
example is driven continuously for a long time, heat is generated
from the piezoelectric element. Therefore, by filling a material
having a high coefficient of thermal conductivity by itself or
resin mixed with a material having a high coefficient of thermal
conductivity in a space between the piezoelectric element and the
holding portion, the generated heat is dispersed to the outside via
the holding portion, so that the piezoelectric element is
effectively prevented from being deteriorated in performance due to
the temperature rise.
APPLICATION EXAMPLE 7
[0026] Preferably, a connecting portion between the inner wall of
the connecting flow channel tube and the inner wall of the fluid
chamber is connected into a substantially arcuate shape.
[0027] In this configuration, the fluid resistance of a
communicating portion between the fluid chamber and the connecting
flow channel tube is reduced, and generation of the vortex flow at
the joint portion is restrained, so that pressure waves generated
when reducing the volume of the fluid chamber is transmitted to the
nozzle without being attenuated.
APPLICATION EXAMPLE 8
[0028] Preferably, the nozzle is inserted into the connecting flow
channel tube and the groove is provided along a joint surface of
the nozzle with respect to the connecting flow channel tube.
[0029] The nozzle and the connecting flow channel tube are coupled
by press-fitting and the joint portion between these members is
reinforced by the adhesive agent, and the joint portion is
hermetically sealed. In this case, it is difficult to apply the
adhesive agent uniformly over the entire portion of the joint
portion. Therefore, by forming the groove on the joint surface of
the nozzle to provide an adhesive agent trap, reinforcement and
hermeticity are ensured.
APPLICATION EXAMPLE 9
[0030] Preferably, the connecting flow channel tube is detachably
attached.
[0031] Here, as a detachably attached structure, for example, a
screwing structure may be employed.
[0032] In this configuration, easy replacement of the connecting
flow channel tube as well as removal for cleaning in the unlikely
event that the nozzle is clogged are achieved.
[0033] Also, there is also an effect that the shape of the
connecting flow channel tube may be selected and attached as needed
according to the object of usage by preparing a plurality of shapes
of the connecting flow channel tube.
APPLICATION EXAMPLE 10
[0034] Application example 10 is directed to a pulsation generating
mechanism having a fluid chamber and an inlet flow channel, and
being configured to discharge fluid supplied from the inlet flow
channel to the fluid chamber in a pulsed manner from a flow channel
being in communication with the fluid chamber by changing the
volume of the fluid chamber including: a diaphragm; a wall surface
provided so as to oppose the diaphragm; a spacer being provided
between the diaphragm and the wall surface and having a cylindrical
through hole; and a piezoelectric element configured to displace
the diaphragm, in which the fluid chamber is defined by the
diaphragm, the wall surface, and an inner surface of the through
hole of the spacer, and the inlet flow channel is defined by a
groove provided on the wall surface and the spacer and is
communicated with the fluid chamber.
[0035] According to the application example, an inertance of the
inlet flow channel side of the fluid chamber may be set to a value
sufficiently larger than that on the outlet flow channel side of
the fluid chamber from both facts that a long flow channel length
of the inlet flow channel is secured, and that the cross sectional
area in the vertical direction with respect to the direction of
flow of the fluid can be set to be small. Accordingly, the
pulsation flow is achieved. Accordingly, a pulsation generating
mechanism having a simple structure in which a check valve is not
provided is realized.
APPLICATION EXAMPLE 11
[0036] Application example 11 is directed to a connecting flow
channel tube which is detachably attached to a pulsation generating
mechanism configured to discharge fluid from an outlet flow channel
in a pulsed manner being in communication with the fluid chamber by
changing the volume of the fluid chamber, being configured to be
communicatable with the outlet flow channel and having a fluid
ejecting opening having a smaller cross-sectional area in the
vertical direction with respect to the direction of flow of the
fluid than the cross-sectional area of the outlet flow channel at
an end opposite to the side which communicates with the outlet flow
channel.
[0037] In this configuration, since the fluid discharged from the
pulsation generating mechanism in a pulsed manner is ejected from
the fluid ejecting opening reduced in cross-sectional area than the
outlet flow channel, so that the fluid is ejected as high-speed
pulsed liquid drops having a high removing performance.
[0038] Also, there is an effect that the shape of the connecting
flow channel tube may be selected and used as needed according to
the object of usage by preparing a plurality of shapes of the
connecting flow channel tube. In addition, by configuring the
connecting flow channel tube to be detachably attached to the
pulsation generating mechanism, the convenience may be further
enhanced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] The invention will be described with reference to the
accompanying drawings where like numbers reference like
elements;
[0040] FIG. 1 is an explanatory drawing showing a schematic
configuration of a fluid ejecting system;
[0041] FIG. 2 is a cross-sectional view of a principal
configuration of a pulsation generating mechanism according to a
first embodiment taken along the direction of flow channel of
liquid;
[0042] FIG. 3 is a side view of the pulsation generating mechanism
viewed from the right side;
[0043] FIG. 4 is a side view of the pulsation generating mechanism
viewed from the left side;
[0044] FIG. 5 is a cross-sectional view showing a joint portion
between a first machine frame and a second machine frame according
to the first embodiment in detail;
[0045] FIG. 6 is a plan view showing the first machine frame in a
state of viewing from the side of a piezoelectric element according
to the first embodiment;
[0046] FIG. 7 is a cross-sectional view showing an inlet port
portion in an enlarged scale according to the first embodiment;
[0047] FIG. 8 is a cross-sectional view showing a joint structure
between a nozzle and a connecting flow channel tube according to
the first embodiment;
[0048] FIG. 9 is a cross-sectional view showing part of a fluid
ejecting apparatus according to a second embodiment;
[0049] FIG. 10A is a cross-sectional view showing part of the fluid
ejecting apparatus according to a third embodiment; and
[0050] FIG. 10B is a cross-sectional view taken along the line E-E
in FIG. 10A.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0051] Referring now to the drawings, embodiments of the invention
will be described.
[0052] FIG. 1 shows a fluid ejecting system, FIGS. 2 to 8 show a
fluid ejecting apparatus according to a first embodiment, FIG. 9
shows a second embodiment, and FIGS. 10A and 10B show a third
embodiment.
[0053] Drawings referred to in the description given below are
schematic drawings in which vertical and lateral reduction scales
of members or portions are different from reality for the sake of
convenience.
[0054] The fluid ejecting system and the fluid ejecting apparatus
in the invention may be employed in various applications such as
drawing using ink or the like, washing of precise substances or
structures, surgical knife, and so on. In the embodiments described
below, a fluid ejecting apparatus suitable for incising or removing
anatomy is exemplified for description. Therefore, fluid used in
the embodiments is liquid such as water or physiologic saline and
the fluid is sometimes expressed as the liquid.
Fluid Ejecting System
[0055] FIG. 1 is an explanatory drawing showing a schematic
configuration of the fluid ejecting system. In FIG. 1, a fluid
ejecting system 1 includes a control device 20 having a liquid
container configured to store the liquid and a pump (not shown) as
a pressure generating unit as a basic configuration, a fluid
ejecting apparatus 10 configured to eject the liquid supplied from
the pump with pulsation, and a connecting tube 25 configured to
communicate the fluid ejecting apparatus 10 with the pump.
[0056] The fluid ejecting apparatus 10 includes a pulsation
generating mechanism 30 configured to discharge supplied liquid at
a high pressure and a high frequency in a pulsed manner, a
connecting flow channel tube 90 connected to the pulsation
generating mechanism 30, and a nozzle 95 having a fluid ejection
opening 97 reduced in cross-section of a flow channel is attached
to a distal end of the connecting flow channel tube 90.
[0057] Subsequently, the flow of the liquid in the fluid ejecting
system 1 will be described. The liquid stored in the liquid
container provided in the control device 20 is supplied to the
pulsation generating mechanism 30 via the connecting tube 25 at a
constant pressure by the pump.
[0058] The pulsation generating mechanism 30 includes a fluid
chamber 120 (see FIG. 2), and a volume changing device for the
fluid chamber 120, and ejects the liquid from the fluid ejection
opening 97 at a high speed in a pulsed manner by driving the volume
changing device and generating pulses. Detailed description of the
pulsation generating mechanism 30 will be described later in
conjunction with FIG. 2 to FIG. 7.
[0059] The pressure generating unit is not limited to the pump, and
a configuration in which an infusion solution bag as the liquid
container is held at a position higher than the pulsation
generating mechanism 30 by a stand or the like is also applicable.
In this case, the pump is not necessary and hence the configuration
is simplified, and in addition, sterilization of a liquid flow
channel is easily achieved.
[0060] A discharge pressure of the pump is set to approximately
three atmospheric pressure (0.3 MPa) or lower. When the infusion
solution bag is used, the difference in height between the
pulsation generating mechanism 30 and a liquid level of the
infusion solution bag corresponds to the pressure, so that the
height difference is preferably set to be approximately 0.1 to 0.15
pressure (0.01 to 0.015 MPa).
[0061] When performing a surgical operation using the fluid
ejecting system 1, a principal portion where the personnel
performing the surgical operation grips is the pulsation generating
mechanism 30. Therefore, the connecting tube 25 to be connected to
the pulsation generating mechanism 30 is preferably flexible as
much as possible. In order to do so, a soft and thin tube is used,
and the pressure of the liquid is preferably as low as possible
within a range which allows delivery of the liquid to the pulsation
generating mechanism 30.
[0062] Also, as in the case of a brain operation in particular,
when the failure of the fluid ejecting system 1 might cause a
critical accident, outburst of high-pressure fluid due to the
breakage of the connecting tube 25 must be avoided. From this
reason, keeping the liquid at a low pressure is required.
First Embodiment
[0063] Subsequently, the structure of the fluid ejecting apparatus
10 according to the first embodiment will be described.
[0064] FIG. 2 is a cross-sectional view showing a principal
structure of a pulsation generating mechanism according to the
first embodiment taken along the direction of the flow channel of
the liquid, FIG. 3 is a side view showing the pulsation generating
mechanism from the right side, and FIG. 4 is a side view showing
the pulsation generating mechanism from the left side.
[0065] Referring now to FIG. 2 to FIG. 4, a schematic configuration
of the fluid ejecting apparatus 10 will be described. The fluid
ejecting apparatus 10 includes the pulsation generating mechanism
30 including a pulsation generating device which generates the
pulsation of the liquid and the connecting flow channel tube 90
having an outlet connecting flow channel 92 and the nozzle 95
configured to discharge the liquid.
[0066] The pulsation generating mechanism 30 includes the fluid
chamber 120 configured by tightly clamping a ring-shaped spacer 60
and a peripheral edge of a diaphragm 70 formed of a disk-shaped
metallic thin plate by opposed surfaces of a first machine frame 80
and a second machine frame 50 as a machine frame and being
surrounded by a wall surface 82 on the second machine frame 50 side
of the first machine frame 80, the diaphragm 70, and an inner
peripheral wall surface of the spacer 60.
[0067] A tube connecting pipe 81 is formed on an outer side surface
of the first machine frame 80 so as to project therefrom, and an
inflow connecting flow channel 84 is opened in the tube connecting
pipe 81. A connecting flow channel 85 which communicates with the
fluid chamber 120 is connected to the inflow connecting flow
channel 84, and is in communication with an inlet flow channel 83
formed on the wall surface 82. The inlet flow channel 83 will be
described in detail in conjunction with FIGS. 5 and 6.
[0068] The connecting tube 25 is fitted to the tube connecting pipe
81, and the connecting tube 25 is connected to the pump provided in
the interior of the control device 20 (see FIG. 1), so that the
liquid is supplied to the fluid chamber 120 via the inlet flow
channel 83.
[0069] The connecting flow channel tube 90 is inserted into the
first machine frame 80 at the substantially center of the wall
surface 82 thereof substantially vertically with respect to the
diaphragm 70 (that is, the wall surface 82). The connecting flow
channel tube 90 includes an outlet flow channel 91 in communication
with the fluid chamber 120 and the outlet connecting flow channel
92 in communication with the outlet flow channel 91, and the nozzle
95 is fitted to an end opposite to the outlet flow channel 91.
[0070] The nozzle 95 includes a nozzle flow channel 96 in
communication with the outlet connecting flow channel 92 and the
fluid ejection opening 97.
[0071] Here, the outlet connecting flow channel 92 and the nozzle
flow channel 96 have the same cross-sectional area, and this
cross-sectional area is larger than the cross-sectional area of the
outlet flow channel 91. Then, the cross-sectional area of the fluid
ejection opening 97 is reduced to be smaller than the
cross-sectional area of the outlet connecting flow channel 92.
[0072] The above-described cross-sectional area means the
cross-sectional area of the flow channel when it is cut vertically
with respect to the direction of flow of the liquid.
[0073] The second machine frame 50 is a cylindrical member having
an outer flange portion 56 and a cylindrical portion 51, and the
outer shapes of the outer flange portion 56 and the cylindrical
portion 51 are both square. Then, a cylindrical hole 51a
penetrating through the second machine frame 50 is formed.
[0074] An opening of the hole 51a on the opposite side to the first
machine frame 80 is sealed by a lower panel 100. A piezoelectric
element 40 as a drive source is provided inside the hole 51a. The
piezoelectric element 40 is a laminated piezoelectric element and
constitutes a column shaped actuator.
[0075] One end of the piezoelectric element 40 is secured to the
diaphragm 70 via an upper panel 110 and the other end thereof is
secured to the inner surface of the lower panel 100.
[0076] Opposing side surfaces of the piezoelectric element 40 are
each provided with a drive electrode (not shown) and connecting
leads 151 and 152 provided with insulating coatings thereon are
connected to these drive electrodes. The connecting leads 151 and
152 are respectively drawn to the outside through lead insertion
holes 54 and 55 formed on the side surfaces of the cylindrical
portion 51 of the second machine frame 50, and are connected to a
drive circuit unit (not shown) of the control device 20 (see FIG.
1).
[0077] The first machine frame 80 and the second machine frame 50
are fixed to each other at four corners with fixing screws 161 in a
state in which the peripheral portion of the diaphragm 70 and the
spacer 60 clamped therebetween, and are brought into tight contact
with each other (see FIG. 4).
[0078] In contrast, the second machine frame 50 and the lower panel
100 are fixed at four corners with the fixing screws 160 after
dimensions are adjusted so as to prevent the diaphragm 70 to be
deformed by the piezoelectric element 40 in an assembled state (see
FIG. 3).
[0079] In this manner, in a state in which the first machine frame
80, the second machine frame 50, and the lower panel 100 are fixed
to each other, resin 140 is filled in a space defined between the
cylindrical portion 51 of the second machine frame 50 and the
piezoelectric element 40. The filling range includes the interior
of the lead insertion holes 54 and 55 in which the connecting leads
151 and 152 are inserted.
[0080] The resin 140 to be filled is preferably a material having a
low water absorbability (or a material having water repellency).
Also, materials having a high coefficient of thermal conductivity
by itself, or resin mixed with a material having a high coefficient
of thermal conductivity are preferable, and inorganic ceramics
powder, carbon powder, and the like having a high coefficient of
thermal conductivity are applicable as the material to be mixed.
Materials which satisfy both conditions of a low water
absorbability and a high coefficient of thermal conductivity are
further preferable.
[0081] Furthermore, the resin, being filled to coat the periphery
of the piezoelectric element 40, has flexibility to an extent which
does not hinder the drive of the piezoelectric element 40.
[0082] Referring now to FIG. 5, a joint portion between the first
machine frame 80 and the second machine frame 50 will be
described.
[0083] FIG. 5 is a cross-sectional view showing the joint portion
between the first machine frame and the second machine frame.
Therefore, description is given with the same reference numerals as
those in FIG. 2.
[0084] The first machine frame 80 includes a ring-shaped recess 86
around the wall surface 82, and the second machine frame 50 is
formed with a ring-shaped projection 53 opposing the ring-shaped
recess 86. By inserting the ring-shaped projection 53 into the
ring-shaped recess 86, an accurate positional restraint between the
first machine frame 80 and the second machine frame 50 is
achieved.
[0085] In this case, the diaphragm 70 and the spacer 60 are
interposed between the wall surface 82 at the center portion of the
first machine frame 80 and an inner periphery flange portion 52
provided inside the ring-shaped projection 53 of the second machine
frame 50 in a compressed state.
[0086] Diameters of an inner peripheral wall 61 of the spacer 60
and the inner periphery flange portion 52 of the second machine
frame 50 are set to be substantially the same, and the supporting
positions with respect to displacement of the diaphragm 70 are the
same.
[0087] A packing 130 as a sealing member is interposed between a
bottom portion of the ring-shaped recess 86 of the first machine
frame 80 and the distal end portion of the ring-shaped projection
53 of the second machine frame 50. The packing 130 is deformed by
being pressed in a state in which the diaphragm 70 and the spacer
60 are interposed in the compressed state, so that the movement of
the liquid between the outside and the fluid chamber 120 is
restrained.
[0088] The connecting flow channel tube 90 is press-fitted into the
first machine frame 80 to a position where the end portion reaches
the fluid chamber 120, and the outlet flow channel 91 is in
communication with the fluid chamber 120. The end surface of the
connecting flow channel tube 90 is machined so as to be flush with
the surface of the wall surface 82 in the fluid chamber 120. In
addition, a connecting portion (communicating portion) of the
outlet flow channel 91 with respect to the fluid chamber 120 is
smoothly connected into a substantially arcuate shape.
[0089] The machining as described above is realized by
press-fitting the connecting flow channel tube 90 from the wall
surface 82 so as to project slightly into the fluid chamber 120,
then grinding the connecting flow channel tube 90 to be flush with
the surface of the wall surface 82, and then by grinding inner
corner of the outlet flow channel 91.
[0090] The inlet flow channel 83 is configured by a groove formed
on the wall surface 82 of the first machine frame 80 and the spacer
60 which seals the opening of the groove.
[0091] Referring now to FIGS. 6 and 7, the inlet flow channel 83
will be described.
[0092] FIG. 6 is a plan view showing the first machine frame in a
state of viewing from the side of the piezoelectric element. The
inlet flow channel 83 is formed as the groove on the wall surface
82 of the first machine frame 80, and is formed into a
substantially arcuate shape extending from the connecting portion
with respect to the connecting flow channel 85 as a proximal end
and to an inlet port portion 83a as a distal end which communicates
with the fluid chamber 120.
[0093] This groove extends from the connecting portion with respect
to the connecting flow channel 85 to a position A in the drawing as
a concentric circle having the outlet flow channel 91 as the
center, and extends in the direction of a tangent line of the inner
peripheral wall 61 of the spacer 60 (that is, in the direction of
the tangent line of the side wall of the fluid chamber 120) in a
range from the positions B to C in the drawing. In addition, in the
range from the positions C to D, the groove extends along the inner
peripheral wall 61 of the spacer 60.
[0094] The range from the positions A to B is connected as a small
arc which changes the direction of flow of the liquid smoothly.
[0095] A most part of an opening of the groove formed in this
manner (upper side in the drawing) is sealed by the ring-shaped
spacer 60 to define the inlet flow channel 83, and the inlet port
portion 83a is in communication with the fluid chamber 120.
[0096] By forming the inlet flow channel 83 in this manner, the
liquid flowing from the connecting tube 25 at a constant pressure
assumes a whirling flow along the inner peripheral wall 61 of the
spacer 60.
[0097] The inlet port portion 83a of the inlet flow channel 83 into
the fluid chamber 120 is continued by an inclined surface 83d from
the bottom surface to the wall surface 82.
[0098] FIG. 7 is a cross-sectional view showing the inlet port
portion in an enlarged scale. The inlet port portion 83a is
continued to the wall surface 82 via the inclined surface 83d from
a groove bottom surface 83b substantially within a range from the
positions C to D (see also FIG. 6) of the inlet flow channel
83.
[0099] Referring now to the drawings, a joint structure between the
nozzle and the connecting flow channel tube in this embodiment will
be described.
[0100] FIG. 8 is a cross-sectional view showing the joint structure
between the nozzle and the connecting flow channel tube. The nozzle
95 includes a distal end flange portion 98 and an insertion portion
99, and includes the nozzle flow channel 96 which communicates with
the outlet connecting flow channel 92 of the connecting flow
channel tube 90 and the fluid ejection opening 97. A groove 99a is
formed on a midsection in terms of the longitudinal direction on
the outer peripheral surface of the insertion portion 99, and a
smaller-diameter tube portion 99b having a smaller outer diameter
is formed at the distal end portion on the insertion side.
[0101] A nozzle insertion hole 90f is formed at the end portion of
the connecting flow channel tube 90. The nozzle 95 is press-fitted
into the nozzle insertion hole 90f. In this case, an end surface
99c of the nozzle 95 is brought into tight contact with a bottom
surface 94 of the nozzle insertion hole 90f.
[0102] The nozzle 95 is press-fitted into the connecting flow
channel tube 90 after an adhesive agent is applied on the outer
peripheral side surface of the insertion portion 99 for
reinforcement of the press-fitting strength. At the time of the
press-fitting, the adhesive agent is accumulated in the groove 99a.
Therefore, the groove 99a in this embodiment corresponds to the
adhesive agent trap, and has a function to enhance the adhesive
strength and a function to prevent liquid leakage or entry of air
at the joint portion between the nozzle 95 and the connecting flow
channel tube 90.
[0103] The smaller-diameter tube portion 99b serves to stop the
adhesive agent within the range of the smaller-diameter tube
portion 99b and prevent the adhesive agent from entering the
interior of the outlet connecting flow channel 92 or the nozzle
flow channel 96.
[0104] Referring now to FIGS. 5 and 6, the operation of the fluid
ejecting apparatus 10 in this embodiment will be described. The
liquid discharge of the pulsation generating mechanism 30 in this
embodiment is performed by the difference between an inertance L1
on the inlet flow channel side (also referred to as synthetic
inertance L1) and an inertance L2 on the outlet flow channel side
(also referred to as synthetic inertance L2).
[0105] First of all, an inertance will be described.
[0106] An inertance L is expressed by L=.rho..times.h/S, where 92
is a density of the liquid, S is the cross-sectional area of the
flow channel, and h is the length of the flow channel. A relation;
.DELTA.P=L.times.dQ/dt is delivered by deforming a dynamic equation
in the flow channel using the inertance L, where .DELTA.P is a
pressure difference in the flow channel, Q is a flow rate of the
liquid flowing in the flow channel, and t is time.
[0107] In other words, the inertance L shows a degree of influence
applied to the change of flow rate with time and, the larger the
inertance L, the smaller the change of flow rate with time is, and
the smaller the inertance L, the larger the change of flow rate
with time is.
[0108] Since the cross-sectional areas of the inflow connecting
flow channel 84 and the connecting flow channel 85 are set to be
sufficiently larger than the cross-sectional area of the inlet flow
channel 83, the synthetic inertance L1 is calculated within the
range of the inlet flow channel 83. In this case, since the
connecting tube 25 has flexibility, it may be eliminated from the
calculation of the synthetic inertance L1.
[0109] Since the connecting flow channel tube 90 has a sufficient
rigidity for propagating pressure waves of the liquid, the
synthetic inertance L2 may be considered to be sum of the outlet
flow channel 91 and the outlet connecting flow channel 92.
[0110] Then, the flow channel length and the cross-sectional area
of the inlet flow channel 83, the flow channel length and the
cross-sectional area of the outlet flow channel 91 and the outlet
connecting flow channel 92 are set so that the synthetic inertance
L1 is larger than the synthetic inertance L2 in this
embodiment.
[0111] Subsequently, the operation of the pulsation generating
mechanism 30 will be described.
[0112] The liquid at an always constant pressure is supplied to the
inlet flow channel 83 by the pump. Consequently, when the
piezoelectric element 40 is not operated, the liquid flows into the
fluid chamber 120 due to the difference between the discharge
pressure of the pump and a fluid resistance value of the entire
inlet flow channel side.
[0113] Here, assuming that a drive signal is inputted to the
piezoelectric element 40, and the piezoelectric element 40 is
expanded abruptly, the pressure in the fluid chamber 120 rises
quickly to several tens atmospheric pressure if the synthetic
inertances L1 and L2 on the inlet flow channel side and the outlet
flow channel side have a sufficient magnitude. Since this pressure
is larger than the pressure by the pump applied to the inlet flow
channel 83 by far, inflow of the liquid from the inlet flow channel
83 into the fluid chamber 120 is reduced by the pressure, and
outflow of the liquid from the outlet flow channel 91 is
increased.
[0114] However, the synthetic inertance L1 on the inlet flow
channel side is larger than the synthetic inertance L2 on the
outlet flow channel side, the amount of increase of the liquid
discharged from the outlet flow channel 91 is larger than the
amount of decrease of the flow rate of the liquid flowing into the
fluid chamber 120 from the inlet flow channel 83. Therefore, a
fluid discharge in a pulsed manner, that is, a pulsation flow is
generated in the outlet flow channel 91.
[0115] Pressure variations at the time of discharge propagate in
the interior of the connecting flow channel tube 90, and the liquid
is ejected from the fluid ejection opening 97 of the nozzle 95 at
the distal end (see FIG. 2 for both). Since the diameter of the
fluid ejection opening 97 is smaller than the diameter of the
outlet flow channel 91, the liquid is ejected as further
high-pressure and high-speed pulsed liquid drops.
[0116] In contrast, the interior of the fluid chamber 120 is
brought into a vacuum state immediately after the pressure rise
because of the mutual action of the reduction of an amount of
inflow liquid from the inlet flow channel 83 and the increase of
the amount of liquid outflow from the outlet flow channel 91.
Consequently, the liquid in the inlet flow channel 83 is restored
to flow toward the fluid chamber 120 at a speed similar to that
before the operation of the piezoelectric element 40 after having
elapsed a certain period of time by the pressure from the pump and
the vacuum state in the fluid chamber 120. If the expansion of the
piezoelectric element 40 occurs after having restored the flow of
the liquid in the inlet flow channel 83, the liquid from the nozzle
95 may be continuously ejected in a pulsed manner.
[0117] This embodiment has a structure to form the inlet flow
channel 83 on the wall surface 82 of the first machine frame 80 as
a groove and seal the opening by the spacer 60. Accordingly, the
synthetic inertance L1 on the inlet flow channel side may be set to
a value sufficiently larger than the synthetic inertance L2 on the
outlet flow channel side from both facts that a long flow channel
length of the inlet flow channel 83 is secured, and that the cross
sectional area in the vertical direction with respect to the
direction of flow of the liquid can be set to be small. Therefore,
a simple structure in which a check valve is not provided is
realized.
[0118] Consequently, an operation to supply the liquid from the
inlet flow channel 83 into the fluid chamber 120 at a constant
pressure, and convert the same to a strong pulsation by the
pulsation generating mechanism 30 is enabled. Therefore, a priming
action is no longer necessary and, since the inflow of the liquid
is continued even though air bubbles are generated, they are
discharged in a certain time period and hence the normal operation
may be restored.
[0119] Also, the inlet flow channel 83 extends along an arcuate
portion extending from the connecting portion (proximal end) with
respect to the connecting flow channel 85, in the direction of the
tangent line of an inner peripheral wall 93 of the spacer 60 from
the arcuate portion, and along the inner peripheral wall 93, and
finally communicates with the fluid chamber 120 from the inlet port
portion 83a. Therefore, the whirling flow is generated in the fluid
chamber 120.
[0120] By the generation of the whirling flow, the liquid is
directed outward from the fluid chamber 120 by a centrifugal force,
and the air bubbles get together at the center portion and are
discharged to the outside in association with discharge of the
liquid from the outlet flow channel 91. Therefore, the air bubbles
are prevented from staying in the fluid chamber 120, and the
pressure in the interior of the fluid chamber 120 may be raised
sufficiently, so that a high-pressure pulsation discharge is
achieved.
[0121] Also, at the inlet port portion 83a where the inlet flow
channel 83 is connected to the fluid chamber 120, the groove bottom
surface 83b which defines the inlet flow channel 83 is continued to
the wall surface 82 via the inclined surface 83d, the fluid
resistance at the connecting portion between the inlet port portion
83a and the fluid chamber 120 is reduced, and the turbulence of the
whirling flow due to a vortex flow generated by the sudden change
of the flow channel is restrained.
[0122] The space in the cylindrical portion 51 of the second
machine frame 50 in which the piezoelectric element 40 is disposed
is filled with the resin 140. Since the resin 140 has a low
absorbability, entry of the water content into the space is
prevented, so that inter-electrode short circuit due to attachment
of the water content to the piezoelectric element 40 is
prevented.
[0123] Since the resin 140 is filled in the lead insertion holes 54
and 55 (see FIG. 2) which allow insertion of the connecting leads
151 and 152, reinforcement of the connecting portion with respect
to the piezoelectric element 40 and the connecting leads 151 and
152 in the second machine frame 50 is achieved.
[0124] In addition, by employing a material having a high
coefficient of thermal conductivity as the resin 140, heat
generated from the piezoelectric element 40 by continuous driving
for a long time is diverged to the outside via the second machine
frame 50, the piezoelectric element 40 is effectively prevented
from being deteriorated in performance due to the temperature
rise.
[0125] Also, since the joint portion with respect to the wall
surface 82 of the outlet flow channel 91 is connected by a
substantially arcuate shape and rounded smoothly, reduction of the
fluid resistance at the joint portion between the fluid chamber 120
and the outlet flow channel 91 is achieved and, in addition,
generation of the vortex flow at the joint portion is restrained,
and the pressure waves generated when reducing the volume of the
fluid chamber 120 is propagated to the nozzle 95 without being
attenuated.
[0126] Also, the groove 99a as the adhesive agent trap is formed on
the joint surface between the nozzle 95 and the connecting flow
channel tube 90. The nozzle 95 and the connecting flow channel tube
90 are coupled by press-fitting and the coupled portion between
these members is reinforced by the adhesive agent. In this case,
with the provision of the adhesive agent trap, the reinforcement of
the strength and the hermeticity are secured.
Second Embodiment
[0127] Subsequently, referring to the drawings, the second
embodiment will be described. The second embodiment is different
from the first embodiment in that the outlet flow channel is
provided on the first machine frame, and the outlet connecting flow
channel provided in the connecting flow channel tube is in
communication with the outlet flow channel. Therefore, the points
different from the first embodiment will mainly be described.
[0128] FIG. 9 is a cross-sectional view showing part of the fluid
ejecting apparatus according to the second embodiment. In FIG. 9,
an outlet flow channel 88 in communication with the fluid chamber
120 is formed on the first machine frame 80, and a connecting flow
channel insertion portion 80a is formed on the opposite side to the
fluid chamber 120 so as to project therefrom, and the center
portion is formed with an insertion hole 80c.
[0129] Then, the connecting flow channel tube 90 is fitted to the
connecting flow channel insertion portion 80a. The outlet
connecting flow channel 92 is formed in the connecting flow channel
tube 90, so that the outlet flow channel 88 and the outlet
connecting flow channel 92 are communicated.
[0130] The flow channel lengths and the cross-sectional areas
(diameters) of the outlet flow channel 88 and the outlet connecting
flow channel 92 are set to similar values as those in the first
embodiment.
[0131] The connecting flow channel tube 90 is press-fitted until a
distal end portion 90g comes into tight contact with a bottom
portion 80b of the insertion hole 80c.
[0132] Also a groove portion 90d is provided at a midsection of a
range of the connecting flow channel tube 90 which is joined with
the insertion hole 80c and a smaller-diameter tube portion 90e
having a smaller outer diameter is provided at a distal end portion
thereof.
[0133] The connecting flow channel tube 90 is press-fitted into the
insertion hole 80c after the adhesive agent is applied on the outer
peripheral surface for reinforcement of the press-fitting strength.
At the time of the press-fitting of the connecting flow channel
tube 90, the adhesive agent is accumulated in the groove portion
90d. Therefore, the groove portion 90d in this embodiment
corresponds to the adhesive agent trap, and has a function to
enhance the adhesive strength and a function to prevent liquid
leakage or entry of air at the joint portion between the connecting
flow channel tube 90 and the first machine frame 80.
[0134] The smaller-diameter tube portion 90e serves to stop the
adhesive agent within the range of the smaller-diameter tube
portion 90e and prevent the adhesive agent from entering the
interior of the outlet flow channel 88 or the outlet connection
flow channel 92.
[0135] In this configuration, the outlet flow channel 88 is formed
in the first machine frame 80. Therefore, since the outlet flow
channel 88 continues with the same surface of the wall surface 82
which constitutes part of the fluid chamber 120, the joint portion
between the connecting flow channel tube 90 and the wall surface 82
is not formed in the fluid chamber 120, so that generation of the
air bubbles caused by the existence of a joint surface is
restrained.
Third Embodiment
[0136] Referring now to the drawings, the fluid ejecting apparatus
according to the third embodiment will be described. While the
connecting flow channel tube 90 is press-fitted into and fixed to
the pulsation generating mechanism 30 (first machine frame 80) in
the first and second embodiment, the connecting flow channel tube
90 is detachable with respect to the pulsation generating mechanism
30 in the third embodiment. Therefore, the different points from
the above-described first and second embodiments will mainly be
described.
[0137] FIGS. 10A and 10B show the fluid ejecting apparatus
according to the third embodiment. FIG. 10A is a cross-sectional
view showing part of the fluid ejecting apparatus, and FIG. 10B is
a cross-sectional view showing a cross section taken along the line
E-E in FIG. 10A. In FIGS. 10A and 10B, the fluid ejecting apparatus
10 is configured in such a manner that the connecting flow channel
tube 90 is fixedly screwed to the pulsation generating mechanism 30
with screw portions of the partner members.
[0138] More specifically, the connecting flow channel insertion
portion 80a is provided on the first machine frame 80 which
constitutes the pulsation generating mechanism 30 opposite to the
fluid chamber 120 so as to project therefrom, and the outlet flow
channel 88 and a connecting flow channel 89 which are in
communication with the fluid chamber 120 are formed in the
connecting flow channel insertion portion 80a. In addition, a
female screw 80d is formed in the range from the distal end portion
of the connecting flow channel insertion portion 80a to the
connecting flow channel 89.
[0139] The outlet connecting flow channel 92 is formed in the
connecting flow channel tube 90, and a male screw 90a is formed on
the outer periphery of the distal end portion. By screwing these
screw portions, the connecting flow channel tube 90 is fixed to the
pulsation generating mechanism 30. Therefore, the connecting flow
channel tube 90 has a configuration which is detachable with
respect to the pulsation generating mechanism 30 (that is, the
first machine frame 80).
[0140] The connecting flow channel tube 90 is screwed in until the
distal end portion 90g comes into tight contact with the bottom
portion 80b of the female screw 80d.
[0141] The diameters of the connecting flow channel 89 and the
outlet connecting flow channel 92 are the same, and the flow
channel length and the cross-sectional area (diameter) of the
outlet flow channel 88, the connecting flow channel 89, and the
outlet connecting flow channel 92, that is, the synthetic inertance
L2 on the outlet flow channel side is set in the same manner as in
the first embodiment 1.
[0142] A cut portion 90b is formed on the outer peripheral portion
at a midsection of the connecting flow channel tube 90 in terms of
the longitudinal direction. As shown in FIG. 10B, the cut portion
90b is formed by cutting the outer periphery of the connecting flow
channel tube 90 into plane surfaces opposing to each other. The cut
portion 90b is used for mounting to and demounting from the
pulsation generating mechanism 30 of the connecting flow channel
tube 90 by rotating the same by a jig or the like.
[0143] Therefore, in this configuration, easy replacement of the
connecting flow channel tube 90 as well as removal for cleaning or
sterilization of the connecting flow channel tube 90 in the
unlikely event that the nozzle 95 is clogged is achieved.
[0144] Also, there is also an effect that the shape of the
connecting flow channel tube 90 may be selected and attached as
needed according to the object of usage by preparing a plurality of
shapes of connecting flow channel tube 90.
Fourth Embodiment
[0145] Subsequently, a fourth embodiment will be described. The
fourth embodiment is characterized in that a coating layer is
formed on an inner wall surface of the fluid chamber. Although not
shown, description will be given on the basis of FIG. 5.
[0146] The fluid chamber 120 is defined by a space surrounded by
the wall surface 82 of the first machine frame 80, the inner
peripheral wall 61 of the spacer 60, and the diaphragm 70. In this
case, a joint portion and corners of the first machine frame 80 and
the wall surface 82, a joint portion and corners of the inner
peripheral wall 61 of the spacer 60 and the diaphragm 70, and a
joint portion between the connecting flow channel tube 90 and the
wall surface 82 are formed.
[0147] Small gaps might be formed at these joint portions due to
the machining reasons, and the inner angle of the corners is 90
degrees.
[0148] The coating layer is formed over the entire periphery of the
inner wall surface of the fluid chamber 120. As an example of the
coating layer, a metal plated layer may be employed. Although the
material of the plated layer is not specifically limited, a
material having a resistance against the liquid to be used is
selected.
[0149] Formation of the plated layer is achieved by inserting the
connecting flow channel tube 90 into the pulsation generating
mechanism 30 and then immersing the same in plating solution, and
by forcing the plating solution to flow from the inflow connecting
flow channel 84 through the inlet flow channel 83 to the outlet
connecting flow channel 92, the plating solution is circulated to
minute portions in the respective flow channels, so that the plated
layer may be formed over the entire flow channels.
[0150] The coating layer is also formed at the corners formed
between the bottom portion and the side walls of the groove of the
inlet flow channel 83 and the corners of the joint portion between
the groove and the spacer 60 which seals the groove. The coating
layer is formed also at the joint portions between the nozzle 95
and the connecting flow channel tube 90.
[0151] Therefore, the continuous thin coating layer is formed over
the entire flow channel for the liquid.
[0152] As described above, the gas contained in the flowing liquid
gets together to small gaps or corners at the joint portions of the
components gradually to generate air bubbles. If the air bubbles
exist in the fluid chamber 120, the internal pressure might not
rise sufficiently when reducing the volume of the fluid chamber 120
by the diaphragm 70.
[0153] Therefore, by embedding the small gap at the joint portions
of the respective components by forming the continuous thin coating
layer over the entire flow channel for the liquid including the
fluid chamber 120 and rounding the corners with the coating layer,
generation of the air bubbles caused by the existence of the small
gaps or corners is restrained, so that the internal pressure in the
fluid chamber 120 may be raised to a predetermined level.
[0154] Although this embodiment has been described on the basis of
the first embodiment described above, it may also be applied to the
second and third embodiments.
* * * * *