JP2006158169A - Electrohydrodynamic pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a production cost by improving the constitution of an electrode in a fluid channel in an EHD pump, reducing a channel resistance of the EHD pump and simplifying a structure for arranging electrode. <P>SOLUTION: In an electrohydrodynamic pump, a linear metal inside electrode is bridged in the inside longitudinal direction of a cylindrical metal outside electrode, exposing itself in the outside electrode, and the outer periphery of the inside electrode is surrounded with a liquid delivery channel tube extending outward of the outside electrode to form a liquid delivery channel. The exposed part of the inside electrode is made to face the inner peripheral surface of the outside electrode, the fluid, which generates dissociated ions when electric field acts, is introduced in the outside electrode and filled in between the outside electrode and the inside electrode, and a high DC voltage is applied between the inside electrode and the outside electrode. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

Detailed Description of the Invention

  The present invention relates to an electrohydrodynamic pump that pumps a fluid in which dissociated ions are generated by applying an electric field between a pair of electrodes to which a direct high voltage is applied. In particular, the present invention relates to a fluid flow path in the pump. Is related to the structure of

  Mechanical pumps that have been used for a long time, that is, pumps that use a rotary blade or a reciprocating piston to send fluid, generate frictional heat, vibration, friction noise, and vibration noise that accompany the movement of the blade and piston. Therefore, research and development for practical application of an electro-hydro-dynamics pump (abbreviated as “EHD pump”) replacing the mechanical pump is in progress. And the EHD pump as shown by Unexamined-Japanese-Patent No. 2003-284316 patent document (patent document 1) is proposed.

The schematic structure of the EHD pump disclosed in Patent Document 1 is as shown in FIG. 8. In the pump case 70, a ring electrode 71 and a columnar electrode 72 having an outer diameter smaller than the outer diameter of the ring electrode 71 are coaxial. The fluid 73 in which dissociated ions are generated when an electric field is applied between the ring-shaped electrode 71 and the columnar electrode 72 that are opposed to each other in the longitudinal direction (the positive ion and the negative ion in the fluid when the electric field is applied). And a DC high voltage is applied between the ring-shaped electrode 71 and the columnar electrode 72 from the power source 74. When a high DC voltage is applied between the ring electrode 71 and the columnar electrode 72, the electric field between the ring electrode 71 and the columnar electrode 72 causes the fluid 73 in the vicinity of the ring electrode 71 and the columnar electrode 72 to flow. Dissociated ions are generated, and a heterocharge layer is formed at the electrode interface. As a result, the fluid 3 is pumped in a flow as indicated by an arrow M7 by the Coulomb force between the ions in the layer and the electrode. However, in such a conventional EHD pump, the electrode group lump in which the ring-shaped electrode 71 and the columnar electrode 72 are coaxially shifted in the longitudinal direction and face each other is placed in the fluid flow path in the pump. In the structure where the ring-shaped electrode 71 and the columnar electrode 72 are opposed to each other while being coaxial and shifted in the longitudinal direction, the manufacturing cost for configuring the electrode arrangement is high. There was a difficult point.
Japanese Patent Laid-Open No. 2003-284316

  In view of the above-mentioned difficulties in the conventional EHD pump, the present invention reduces the flow resistance of the EHD pump and simplifies the electrode arrangement structure by improving the electrode configuration in the fluid flow path in the pump. It is intended to reduce manufacturing costs.

  In order to solve this problem, in the present invention, a linear inner electrode is installed in an exposed state in the longitudinal direction inside a cylindrical outer electrode sealed at both ends by an electrically insulating end plate provided with fluid return holes. A fluid delivery passage tube extending outside the outer electrode to surround the inner electrode to form a fluid delivery passage, and the exposed portion of the inner electrode is opposed to the inner peripheral surface of the outer electrode so that an electric field is generated. When activated, a fluid that generates dissociated ions is introduced into the outer electrode, the fluid is filled between the outer electrode and the inner electrode, and a DC high voltage is applied between the inner electrode and the outer electrode to Configure a hydrodynamic pump.

  As a practically preferable means, a linear inner electrode is coaxially exposed in the longitudinal direction inside the cylindrical outer electrode sealed at both ends by an electrically insulating end plate provided with fluid return holes. The fluid delivery flow path tube extending outside the outer electrode surrounds the inner electrode to form a fluid delivery flow path, and the exposed portion of the inner electrode is opposed to the inner peripheral surface of the outer electrode so that an electric field acts Then, a fluid in which dissociated ions are generated is introduced into the outer electrode, the fluid is filled between the outer electrode and the inner electrode, and a DC high voltage is applied between the inner electrode and the outer electrode to Configure a hydrodynamic pump.

  It is also effective to provide a plurality of fluid delivery channel tubes, and the linear inner electrode is exposed in the longitudinal direction inside the cylindrical outer electrode sealed at both ends with an electrically insulating end plate provided with fluid return holes. A fluid delivery channel is formed by surrounding the inner electrode with two fluid delivery channel tubes that are installed in a state and extend in opposite directions to the outside of the outer electrode, and the exposed portion of the inner electrode is outside Opposite the inner peripheral surface of the electrode, a fluid that generates dissociated ions when an electric field acts is introduced into the outer electrode to fill the fluid between the outer electrode and the inner electrode. An electrohydrodynamic pump is configured by applying a direct current high voltage between the two.

  Furthermore, a linear inner electrode is exposed in the longitudinal direction inside the cylindrical outer electrode sealed at both ends with an electrically insulating end plate provided with fluid return holes, and extends outside the outer electrode. The fluid delivery flow path tube surrounds the inner electrode to form a fluid delivery flow path, and the exposed portion of the inner electrode is opposed to the inner peripheral surface of the outer electrode so that dissociated ions are generated when an electric field is applied. Is introduced into the outer electrode, the fluid is filled between the outer electrode and the inner electrode, a DC high voltage is applied between the inner electrode and the outer electrode, and a plurality of the outer electrodes are formed. These pumps are connected in parallel or in series via the fluid delivery channel pipe and the fluid return channel pipe communicating with the fluid return hole, thereby expanding the pump capacity.

  As described above, in the configuration of the electrohydrodynamic pump according to the present invention, there is no movable mechanism, and no electrode group having a large flow path resistance in the flow direction of the fluid is provided in the flow path in the pump. A large pressure head can be obtained without generating frictional noise and vibration noise, and since the electrode arrangement structure is extremely simple, the manufacturing cost can be kept low. Furthermore, in principle, there is a great feature that no electrical noise is generated because the electromagnetic induction phenomenon as in the conventional pump is not used. Therefore, for example, if the electric rain-heavy rain dynamics pump according to the present invention is used for a cooling unit such as a precision electronic device, an extremely great effect can be expected.

    In a preferred embodiment of the present invention, a linear inner electrode is coaxially exposed so as to penetrate the inside of a cylindrical outer electrode sealed at both ends with an electrically insulating end plate provided with fluid return holes. The two fluid delivery channel pipes extending in opposite directions to the outside of the outer electrode surround the inner electrode to form a fluid delivery channel, and at least the length L is set to 0.7 mm. The exposed portion of the inner electrode is opposed to the inner peripheral surface of the outer electrode, and a fluid that generates dissociated ions when an electric field acts is introduced into the outer electrode, and the fluid is interposed between the outer electrode and the inner electrode. And a fluid return flow path that applies a DC high voltage between the inner electrode and the outer electrode, and communicates with at least two of the outer electrodes, the fluid delivery flow path pipe, and the fluid return hole. Connected in parallel or in series via a tube It is the electrohydrodynamic pump. Note that when the length L of the exposed portion of the inner electrode is 0.7 mm or less, a sufficient pressure head cannot be obtained. On the other hand, there is no problem in increasing the length L to mm or more depending on the object on which the pump is installed, but the pressure head does not increase any more and shows a saturation tendency.

  Examples of the present invention will be described below. FIG. 1 is a longitudinal sectional view of an electrohydrodynamic pump showing an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line AA 'of the electrohydrodynamic pump shown in FIG. 1 and 2, 1 is a linear inner electrode having an outer diameter a, and the length of the exposed portion 1a of the inner electrode 1 is L. Reference numeral 2 denotes a cylindrical outer electrode having an inner diameter b, and the length of the outer electrode 2 is N. The material of the inner electrode 1 and the outer electrode 2 is stainless steel, and the inner electrode 1 and the outer electrode 2 are arranged coaxially. Reference numerals 3 and 4 denote electrically insulating fluid delivery channel tubes, and 3a and 4a denote delivery ports of the fluid delivery channel tubes 3 and 4, respectively. Reference numerals 5 and 6 denote electrically insulating end plates, and both end faces of the outer electrode 2 are sealed with electrically insulating end plates 5 and 6, respectively. 7 is a fluid in which dissociated ions are generated when an electric field acts, and 8 is a DC high-voltage power source. Reference numerals 9 and 10 denote electrically insulating fluid return channels, and 9a and 10a denote fluid return ports of the fluid return channels 9 and 10, respectively. The center portions of the insulating end plates 5 and 6 are connected to the fluid delivery channel tubes 3 and 4, respectively, and the fluid return ports 9 a and 10 a of the fluid return channel tubes 9 and 10 are provided near the inner surface of the outer electrode 2. Is connected. The outer electrode 2 is always kept at the ground potential through the ground wire 11, and when a DC high voltage is applied between the linear inner electrode 1 and the cylindrical outer electrode 2, the inner electrode 1 and the outer electrode 2 A strong electric field is formed between them. Since the inner electrode 1 and the outer electrode 2 are arranged coaxially, an unequal electric field is formed, and a strong electric field is formed particularly near the surface of the inner electrode 1. Therefore, in the case of a weakly conductive fluid in which negative ions are easily generated as dissociative ions, if a positive potential is applied to the inner electrode 1 and a negative potential is applied to the outer electrode 2, “pure conduction pumping” (see above patent) The pressure toward the center of the axis is generated between the heterocharge layer formed around the inner electrode 1 and the inner electrode 1 based on the mechanism described in Document 1) by the force of the ions in the layer pushing in the normal direction of the electrode surface. To do. This pressure cancels out over the entire exposed inner electrode surface in a vector manner, and its integrated value becomes zero. However, in the vicinity of the delivery ports 3a and 4a of the fluid delivery channel tubes 3 and 4, the pressure is reduced. As a result, there is a new pressure difference in the axial direction toward the delivery ports 3a and 4a of the fluid delivery channel tubes 3 and 4, which becomes a pumping drive source.

  As described above, when a DC high voltage is applied between the inner electrode 1 and the outer electrode 2 and the surface electric field strength of the inner electrode exposed portion 1a becomes a high electric field strength of about 5 to 12 MV / m, the cylindrical outer electrode A strong electric field directed from 2 to the exposed portion 1a of the linear inner electrode 1 acts on the fluid 7, and a large pressure acts on the fluid 7 in the vicinity of the surface of the inner electrode exposed portion 1a as described above. 1a and the fluid delivery flow path pipes 3 and 4 flow in the axial direction along the fluid 7 to generate a pump function, and the fluid 7 discharged from the fluid delivery flow path pipes 3 and 4 passes through the external pipelines The return flow pipes 9 and 10 circulate by flowing into the fluid return ports 9a and 10a, respectively.

As another embodiment of the EHD pump according to the present invention, the configuration is changed based on the EHD pump shown in the first embodiment, and a fluid flow hole having a diameter of 5 mm is newly provided in each of the electrically insulating end plates 5 and 6. And using a metal wire with an outer diameter (diameter / wire diameter) of a = 1.5 mm as the linear inner electrode 1. The length N of the cylindrical outer electrode 2 was set to 50 mm, and the pump structure was immersed in a tank filled with a fluid 7 in which dissociated ions were generated when an electric field was applied, and the pumping characteristics were measured. After using 2,3-dihydrodecafluoropentene (abbreviated as “HFC43-10”) (trade name: Bertrell) as the fluid 7, the inner diameter b of the cylindrical outer electrode 2, As a result of measuring the pumping pressure P _EHD by changing the exposed portion length L of the inner electrode 1 and the applied voltage (DC high voltage) V ₀ applied between the inner electrode 1 and the outer electrode 2, respectively, 3 and the characteristics shown in FIG. 4 were observed.

FIG. 3 shows the relationship of the pumping pressure P _EHD with respect to the applied voltage V _{0 using} the inner diameter b (= R ₀ ) of the outer electrode 2 as a parameter. That is, since the electric field between the inner electrode 1 and the outer electrode 2 becomes stronger as the inner diameter b of the outer electrode 2 becomes smaller, a characteristic that the pumping pressure increases in a quadratic curve is recognized. On the other hand, FIG. 4 shows changes in the pumping pressure P _EHD when the exposed portion length L of the inner electrode 1 is changed using the inner diameter b (= R ₀ ) of the outer electrode 2 as a parameter. In FIG. 4, the white symbols indicate the case where the applied voltage V ₀ = 10 kV, and the black symbols indicate the case where the applied voltage V ₀ = 14 kV. Naturally, a higher pumping pressure P _EHD is obtained when the applied voltage V ₀ is higher, but on the other hand, regardless of the applied voltage V ₀ , the inner electrode 1 It was confirmed that even if the exposed portion length L of the film was made longer, the pumping pressure P _EHD did not increase and became saturated. Therefore, the result that the minimum value of the exposed portion length L of the inner electrode 1 was 0.7 mm was obtained.

    Next, an embodiment in which the electrohydrodynamic pump according to the present invention is used as a cooling unit will be described with reference to FIG. In FIG. 5, reference numeral 20 denotes an electrohydrodynamic pump section (EHD pump section) similar to that described above according to the present invention. 1a is an exposed portion of the inner electrode, 2 is an outer electrode, 3 and 4 are fluid delivery channel tubes, 5 , 6 are electrically insulating end plates, 7 is a fluid in which dissociated ions are generated, 8 is a DC high-voltage power supply, 9 and 10 are fluid return flow channel tubes, and 11 is a ground wire. Reference numeral 21 denotes a Peltier electronic cooling element. The Peltier electronic cooling element 21 is attached in close contact with the outer side of the outer electrode 2. Reference numerals 22 and 23 denote aluminum cooling units, to which the fluid delivery passage pipes 3 and 4 and the fluid return passage pipes 9 and 10 are connected, respectively. Reference numerals 24 and 25 denote heat absorption surfaces (cooled surfaces) of the cooling units 22 and 23, and reference numerals 26 and 27 denote fluid flow direction control partition plates in the cooling units 22 and 23, respectively. In this embodiment, the length N of the outer electrode 2 is set to 20 mm, the DC high-voltage power supply 8 is set to 8 kV, HFC43-10 (trade name: Vertrel) is used for the fluid 7 serving as a refrigerant, and the Peltier electronic cooling element 21 is used. Is set to −10 ° C., and the fluid 7 is circulated by the EHD pump unit 20. As a result, the temperature of the heat absorbing surfaces (cooled surfaces) 24 and 25 of the cooling units 22 and 23 reaches approximately −10 ° C. in about 20 minutes. did. In this example, the endothermic surfaces (cooled surfaces) 24 and 25 were provided at two locations, but no trouble occurred even when the endothermic surfaces (cooled surfaces) were operated as one location. Further, if the length N of the outer electrode 2 is set to 0.7 mm or more in accordance with the cooling capacity of the Peltier electronic cooling element 21, there is no problem in pump performance even if various changes are made. Further, the connection of the fluid return flow path pipes 9 and 10 can be switched depending on the installation state of the pump. In addition to HFC43-10, fluid 7 in which dissociated ions are generated when an electric field is applied includes 2,2-dichloro-1,1,1 trifluoroethane (2,2-Dichloro-1,1,1- Trifluoroethane (abbreviated as “HCFC123”), diethyl glycol monobutyl ether acetate (abbreviated as “BCRA”), dodecanedioic acid-n-butyl (abbreviated as “DBDN”), fluorine-modified silicone oil, etc. There is no problem in adding a slight amount of alcohol to the electrical insulating liquid or adding fluorine to increase the ability to generate dissociated ions.

Furthermore, as another embodiment of the EHD pump according to the present invention, as shown in FIG. 6, two electrohydrodynamic pumps are connected in series via a fluid delivery channel tube 3 and a fluid return channel tube 9. It was also possible to drive. In this case, the outer diameter of the pump is the same as in Example 3, the fluid 7 is HFC43-10 (trade name: Bartrel), the applied voltage V ₀ DC is set to 8 kV for both pumps, and the fluid 7 Were circulated with fluid delivery channel tube 3 -fluid return channel tube 9 -fluid delivery channel tube 3. As a result, a maximum of 4 kPa was obtained according to the pressure gauge installed in the external pipeline.

Furthermore, as shown in FIG. 7, two electrohydrodynamic pumps could be coupled and driven in parallel via the fluid delivery channel tube 3 and the fluid return channel tube 9. The fluid 7 and the driving conditions here are the same as those in the fourth embodiment, but a check valve 31 is used to prevent one pump delivery fluid from flowing backward to the outlet (fluid delivery conduit) of the other pump. Arranged. As a result, according to the pressure gauge installed in the external pipeline, a maximum of 2 kPa was obtained, and the flow rate reached twice.

  In the electrohydrodynamic pump according to the present invention, there is no movable mechanism, and since there is no electrode group having a large flow path resistance in the fluid flow direction, a large pressure head can be obtained without generating frictional noise and vibration noise. Since the electrode arrangement structure is very simple, the manufacturing cost can be kept low. Furthermore, in principle, no electrical noise is generated because the electromagnetic induction phenomenon as in the conventional pump is not used. Therefore, the present invention can be applied to a very wide range of fields and applications such as cooling units such as precision electronic circuit parts. The electrohydrodynamic pump according to the above can be utilized.

  The front view of the electrohydrodynamic pump which shows one Example of this invention.   FIG. 2 is a cross-sectional view taken along line AA ′ in FIG. 1.   The relationship figure of the pumping pressure with respect to the applied voltage of the same electrohydrodynamic pump.   The related figure of the pumping pressure with respect to the exposed part length of the inner side electrode of the same electrohydrodynamic pump.   The schematic block diagram which utilized the electrohydrodynamic pump for the cooling unit.   The schematic block diagram which uses two said electrohydrodynamic pumps connected in series.   The schematic block diagram which uses two said electrohydrodynamic pumps connected in parallel.   Sectional drawing of the conventional electrohydrodynamic pump.

Explanation of symbols

1: inner electrode 1a: exposed portion of inner electrode 2: outer electrode 3, 4: fluid delivery channel tube 3a, 4a: outlet of fluid delivery channel tube 5, 6: electrically insulating end plates 5a, 6a: fluid Return hole 7: Fluid in which dissociated ions are generated 8: DC high-voltage power supply 9, 10: Fluid return channel tube 9a, 10a: Return port 11 of fluid return channel tube: Ground wire 20: Electrohydrodynamic pump portion 21: Peltier electronic cooling elements 22, 23: Cooling units 24, 25: Endothermic surfaces 26, 27: Fluid flow direction control partition plate 31: Check valve a: Outer diameter of inner electrode b: Inner electrode inner diameter L: Inner electrode exposure _Part length N: Length of outer electrode P _EHD : Pumping pressure R ₀ : Inner diameter (radius) of outer electrode
V ₀ : Applied voltage

Claims (13)

  A fluid delivery system in which a linear inner electrode is exposed in the longitudinal direction inside a cylindrical outer electrode sealed at both ends by an electrically insulating end plate provided with a fluid return hole, and extends outside the outer electrode. A fluid delivery channel is formed by surrounding the inner electrode with a channel tube, and an exposed portion of the inner electrode is opposed to an inner peripheral surface of the outer electrode, and a fluid in which dissociated ions are generated when an electric field is applied to the fluid. An electrohydrodynamic pump that is introduced into an outer electrode, fills the fluid between the outer electrode and the inner electrode, and applies a DC high voltage between the inner electrode and the outer electrode.   A linear inner electrode is coaxially exposed in the longitudinal direction inside the cylindrical outer electrode sealed at both ends with an electrically insulating end plate provided with fluid return holes, and extends outside the outer electrode. The fluid delivery channel tube surrounds the inner electrode to form a fluid delivery channel, and the exposed portion of the inner electrode is opposed to the inner peripheral surface of the outer electrode. When an electric field is applied, dissociated ions are generated. An electrohydrodynamic pump characterized by introducing a fluid into the outer electrode, filling the fluid between the outer electrode and the inner electrode, and applying a DC high voltage between the inner electrode and the outer electrode. .   A linear inner electrode is installed in an exposed state in the longitudinal direction inside a cylindrical outer electrode sealed at both ends by an electrically insulating end plate provided with fluid return holes, and opposite to each other on the outside of the outer electrode. Two fluid delivery channel pipes extending to the inner electrode surround the inner electrode to form a fluid delivery channel, and the exposed portion of the inner electrode is opposed to the inner peripheral surface of the outer electrode, and dissociates when an electric field acts. A fluid in which ions are generated is introduced into the outer electrode, the fluid is filled between the outer electrode and the inner electrode, and a DC high voltage is applied between the inner electrode and the outer electrode. Electrohydrodynamic pump.   A linear inner electrode is coaxially exposed in the longitudinal direction inside the cylindrical outer electrode sealed at both ends by an electrically insulating end plate provided with fluid return holes, and is externally connected to the outside of the outer electrode. The fluid delivery channel is formed by surrounding the inner electrode with two fluid delivery channel tubes extending in opposite directions, and the exposed portion of the inner electrode is opposed to the inner peripheral surface of the outer electrode so that an electric field is generated. Introducing a fluid that generates dissociated ions into the outer electrode when acted, fills the fluid between the outer electrode and the inner electrode, and applies a DC high voltage between the inner electrode and the outer electrode. Electrohydrodynamic pump characterized by   A fluid delivery system in which a linear inner electrode is exposed in the longitudinal direction inside a cylindrical outer electrode sealed at both ends by an electrically insulating end plate provided with a fluid return hole, and extends outside the outer electrode. A fluid delivery channel is formed by surrounding the inner electrode with a channel tube, and an exposed portion of the inner electrode is opposed to an inner peripheral surface of the outer electrode, and a fluid in which dissociated ions are generated when an electric field is applied to the fluid. Introduced into the outer electrode, the fluid is filled between the outer electrode and the inner electrode, a DC high voltage is applied between the inner electrode and the outer electrode, and a plurality of the outer electrodes are supplied to the fluid. An electrohydrodynamic pump characterized in that it is connected in series via a flow path pipe and a fluid return flow path pipe communicating with the fluid return hole.   A linear inner electrode is coaxially exposed in the longitudinal direction inside the cylindrical outer electrode sealed at both ends with an electrically insulating end plate provided with fluid return holes, and extends outside the outer electrode. The fluid delivery channel tube surrounds the inner electrode to form a fluid delivery channel, and the exposed portion of the inner electrode is opposed to the inner peripheral surface of the outer electrode. When an electric field is applied, dissociated ions are generated. Introducing a fluid into the outer electrode to fill the fluid between the outer electrode and the inner electrode, applying a DC high voltage between the inner electrode and the outer electrode, and a plurality of the outer electrodes; An electrohydrodynamic pump characterized by being connected in series via the fluid delivery channel pipe and a fluid return channel pipe communicating with the fluid return hole.   A linear inner electrode is installed in an exposed state in the longitudinal direction inside a cylindrical outer electrode sealed at both ends by an electrically insulating end plate provided with fluid return holes, and opposite to each other on the outside of the outer electrode. Two fluid delivery channel pipes extending to the inner electrode surround the inner electrode to form a fluid delivery channel, and the exposed portion of the inner electrode is opposed to the inner peripheral surface of the outer electrode, and dissociates when an electric field acts. A fluid in which ions are generated is introduced into the outer electrode to fill the fluid between the outer electrode and the inner electrode, a direct current high voltage is applied between the inner electrode and the outer electrode, and the outer electrode An electrohydrodynamic pump characterized in that a plurality of electrodes are connected in series via the fluid delivery channel tube and the fluid return channel tube communicating with the fluid return hole.   A linear inner electrode is coaxially exposed in the longitudinal direction inside the cylindrical outer electrode sealed at both ends by an electrically insulating end plate provided with fluid return holes, and is externally connected to the outside of the outer electrode. The fluid delivery channel is formed by surrounding the inner electrode with two fluid delivery channel tubes extending in opposite directions, and the exposed portion of the inner electrode is opposed to the inner peripheral surface of the outer electrode so that an electric field is generated. When introduced, a fluid that generates dissociated ions is introduced into the outer electrode to fill the fluid between the outer electrode and the inner electrode, and a DC high voltage is applied between the inner electrode and the outer electrode, An electrohydrodynamic pump characterized in that a plurality of the outer electrodes are connected in series via the fluid delivery channel tube and a fluid return channel tube communicating with the fluid return hole.   A fluid delivery system in which a linear inner electrode is exposed in the longitudinal direction inside a cylindrical outer electrode sealed at both ends by an electrically insulating end plate provided with a fluid return hole, and extends outside the outer electrode. A fluid delivery channel is formed by surrounding the inner electrode with a channel tube, and an exposed portion of the inner electrode is opposed to an inner peripheral surface of the outer electrode, and a fluid in which dissociated ions are generated when an electric field is applied to the fluid. Introduced into the outer electrode, the fluid is filled between the outer electrode and the inner electrode, a DC high voltage is applied between the inner electrode and the outer electrode, and a plurality of the outer electrodes are supplied to the fluid. An electrohydrodynamic pump characterized by being coupled in parallel via a flow path pipe and a fluid return flow path pipe communicating with the fluid return hole.   A linear inner electrode is coaxially exposed in the longitudinal direction inside the cylindrical outer electrode sealed at both ends with an electrically insulating end plate provided with fluid return holes, and extends outside the outer electrode. The fluid delivery channel tube surrounds the inner electrode to form a fluid delivery channel, and the exposed portion of the inner electrode is opposed to the inner peripheral surface of the outer electrode. When an electric field is applied, dissociated ions are generated. Introducing a fluid into the outer electrode to fill the fluid between the outer electrode and the inner electrode, applying a DC high voltage between the inner electrode and the outer electrode, and a plurality of the outer electrodes; An electrohydrodynamic pump characterized by being coupled in parallel through the fluid delivery channel tube and a fluid return channel tube communicating with the fluid return hole.   A linear inner electrode is installed in an exposed state in the longitudinal direction inside a cylindrical outer electrode sealed at both ends by an electrically insulating end plate provided with fluid return holes, and opposite to each other on the outside of the outer electrode. Two fluid delivery channel pipes extending to the inner electrode surround the inner electrode to form a fluid delivery channel, and the exposed portion of the inner electrode is opposed to the inner peripheral surface of the outer electrode, and dissociates when an electric field acts. A fluid in which ions are generated is introduced into the outer electrode to fill the fluid between the outer electrode and the inner electrode, a direct current high voltage is applied between the inner electrode and the outer electrode, and the outer electrode An electrohydrodynamic pump characterized in that a plurality of electrodes are coupled in parallel via the fluid delivery channel tube and the fluid return channel tube communicating with the fluid return hole.   A linear inner electrode is coaxially exposed in the longitudinal direction inside the cylindrical outer electrode sealed at both ends by an electrically insulating end plate provided with fluid return holes, and is externally connected to the outside of the outer electrode. The fluid delivery channel is formed by surrounding the inner electrode with two fluid delivery channel tubes extending in opposite directions, and the exposed portion of the inner electrode is opposed to the inner peripheral surface of the outer electrode so that an electric field is generated. When introduced, a fluid that generates dissociated ions is introduced into the outer electrode to fill the fluid between the outer electrode and the inner electrode, and a DC high voltage is applied between the inner electrode and the outer electrode, An electrohydrodynamic pump characterized in that a plurality of the outer electrodes are coupled in parallel via the fluid delivery channel tube and the fluid return channel tube communicating with the fluid return hole.   13. The electrohydrodynamic pump according to claim 1, wherein the length L of the exposed portion of the inner electrode is set to at least 0.7 mm.

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