Electrohydrodynamic Pump

Abstract

To provide an electro-hydrodynamic pump in which a specification can be easily changed.SOLUTION: An electro-hydrodynamic pump 1 according to an embodiment of the present invention is an electro-hydrodynamic pump that generates a flow in an object fluid by applying a voltage to the object fluid having an insulation property. The electro-hydrodynamic pump comprises: a plurality of pump modules 10 that are serially arranged and apply the voltage to the object fluid, respectively; and a connection member 20 that connects both of the adjacent pump modules 10. Each of the pump modules 10 includes: an action part 11 that is formed of an insulation material, and defines an action channel 111 applying the voltage to the object fluid; a pair of electrodes 12 and 13 applying an electric field to the action channel 111; a cylinder casing part 14 that is formed of the insulation material, and houses the action part 11; and a pair of fixing structure parts 15 that is integrally provided to both ends of the casing part 14 and is held by the connection member 20.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to electrohydrodynamic pumps. [Background technology]

[0002] The electrohydrodynamic effect is known, in which applying a voltage to an insulating fluid causes the fluid to flow. An electrohydrodynamic pump has been proposed that uses this electrohydrodynamic effect to discharge a fluid. Since electrohydrodynamic pumps do not require moving parts such as an impeller, they can be made compact.

[0003] In electrohydrodynamic pumps, increasing the voltage is an effective way to increase the discharge volume and pressure, but increasing the voltage can lead to problems such as the circuit becoming expensive and being easily affected by surrounding metals.As a method for increasing the discharge volume and pressure while suppressing the voltage, an electrohydrodynamic pump has been proposed in which multiple electrode pairs are arranged in multiple stages along the flow path, and the fluid is pressurized in sequence by the multiple electrode pairs (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-63342 A Summary of the Invention [Problem to be solved by the invention]

[0005] Since changing the number and arrangement of electrode pairs in the design according to the required specifications increases the cost of the electrohydrodynamic pump, an object of the present invention is to provide an electrohydrodynamic pump whose specifications can be easily changed. [Means for solving the problem]

[0006] An electrohydrodynamic pump according to one embodiment of the present invention is an electrohydrodynamic pump that generates a flow in an insulating target fluid by applying a voltage to the target fluid, and comprises a plurality of pump modules arranged in series, each of which applies a voltage to the target fluid, and a connecting member that connects adjacent pump modules, and each of the pump modules has an action portion formed of an insulating material and defining an action flow path through which a voltage is applied to the target fluid, a pair of electrodes that apply an electric field to the action flow path, a cylindrical casing portion formed of an insulating material and accommodating the action portion, and a pair of fixing structural portions that are integrally formed on both ends of the casing portion and held by the connecting member.

[0007] In the above-mentioned electrohydrodynamic pump, the fixed structural portion may be integrally formed with the casing portion from an insulating material.

[0008] In the above-mentioned electrohydrodynamic pump, the fixed structure and the connecting member may form a pipe joint.

[0009] In the above-mentioned electrohydrodynamic pump, the fixing structure may be a ferrule, and the connecting member may be a clamp band.

[0010] In the electrohydrodynamic pump described above, the plurality of pump modules may include pump modules having working flow paths with different shapes. Effect of the Invention

[0011] According to the present invention, it is possible to provide an electrohydrodynamic pump whose specifications can be easily modified. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic cross-sectional view showing a configuration of an electrohydrodynamic pump according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a schematic cross-sectional view showing the configuration of an electrohydrodynamic pump 1 according to an embodiment of the present invention.

[0014] The electrohydrodynamic pump 1 in Fig. 1 is a pump that applies a voltage to an insulating target fluid to cause the target fluid to flow. The electrohydrodynamic pump 1 includes a plurality of pump modules 10 arranged in series, each of which applies a voltage to the target fluid, and a plurality of connection members 20 that connect adjacent pump modules 10 to each other. Note that the electrohydrodynamic pump 1 shown in the figure includes three pump modules 10, but the number of pump modules 10 is not particularly limited.

[0015] The pump module 10 has an action portion 11 formed of an insulating material and defining an action flow path 111 through which a voltage is applied to the target fluid, a pair of electrodes (a first electrode 12 and a second electrode 13) that apply an electric field to the action flow path 111, a cylindrical casing portion 14 formed of an insulating material and accommodating the action portion 11, and a pair of fixing structure portions 15 integrally formed on both ends of the casing portion 14 and held by a connecting member 20.

[0016] It is preferable that the casing portion 14 and the fixed structure portion 15 of each pump module 10 all have the same shape, but the working portion 11 (particularly the working flow path 111) and the electrodes 12, 13 may have different shapes for each pump module 10. In other words, the electrohydrodynamic pump 1 can be formed by combining pump modules 10 having working flow paths 111 with different shapes. The characteristics of the electrohydrodynamic pump 1 will differ depending on the combination of pump modules. Therefore, electrohydrodynamic pumps 1 with a variety of specifications can be realized simply by preparing a relatively small number of pump modules 10 with different specifications and selecting a combination of these.

[0017] In the electrohydrodynamic pump 1 of FIG. 1, all components of the first pump module 10 and the third pump module 10 counting from the upstream side have the same shape. However, the second pump module 10 has a first electrode 12, a second electrode 13, a casing portion 14, and a fixed structure portion 15 having the same shapes as those of the first and third pump modules 10, but has an action portion 11 (particularly, an action flow path 111) having a different shape from those of the first and third pump modules 10. More specifically, the action flow paths 111 of the first and third pump modules 10 are cylindrical flow paths with a constant diameter, while the action flow path 111 of the second pump module 10 is a truncated cone-shaped flow path whose diameter decreases at a constant rate toward the downstream side. In the illustrated example, the first electrode 12 and the second electrode 13 of all the pump modules 10 are the same, but the shapes of either or both of the first electrode 12 and the second electrode 13 may be different corresponding to the action flow path 111.

[0018] When the working flow channel 111 has a constant cross-sectional area, the flow resistance is small and a voltage can be applied evenly to the target fluid, so that a relatively large discharge flow rate can be obtained. On the other hand, when the cross-sectional area of ​​the working flow channel 111 decreases toward the downstream side, the pressure of the target fluid can be increased in the working flow channel 111, so that the discharge pressure can be made larger. By combining pump modules 10 having such working flow channels 111 with different shapes, an electrohydrodynamic pump 1 having desired discharge characteristics can be obtained.

[0019] When increasing the differential pressure in the pump module 10, the ratio of the diameter (equivalent circle diameter) of the inlet of the action flow path 111 to the diameter of the outlet is preferably 5 to 20, more preferably 8 to 15. The ratio of the diameter of the action flow path 111 to the flow path length can be, for example, 1 to 10, preferably 2 to 8. By increasing the rate of reduction in the diameter per flow path length of the action flow path 111 within such a range, the differential pressure in the pump module 10 can be efficiently increased.

[0020] The action part 11 is disposed so as to divide the inside of the casing part 14, and an action flow path 111 is formed penetrating therethrough so as to communicate the upstream space with the downstream space of the casing part 14. Moreover, the action part 11 preferably has holding structures 112, 113 for holding the first electrode 12 and the second electrode 13, respectively, on both sides of the action flow path 111. In this embodiment, the holding structures 112, 113 are countersunk recesses for receiving the first electrode 12 and the second electrode 13, and further receiving annular pressing members 114, 115 for pressing the outer peripheries of the first electrode 12 and the second electrode 13.

[0021] The action part 11 is preferably disposed so as not to leave a gap between it and the casing part 14, so that the target fluid can pass only through the action flow path 111. For this reason, the action part 11 may be formed integrally with the casing part 14 by a method such as cutting. Also, in order to facilitate the formation of action flow paths 111 of various shapes, the action part 11 may be formed independently and then fixed inside the casing part 14 by a method such as press fitting.

[0022] When the working fluid is negatively ionized, a voltage is applied between the first electrode 12 and the second electrode 13, with the first electrode 12 being negative. The first electrode 12 and the second electrode 13 cover the inlet and outlet of the working flow path 111, and have a shape with openings or gaps through which the target fluid can pass, and are preferably in the form of a mesh with a large contact area with the target fluid. Specifically, the first electrode 12 and the second electrode 13 can be formed of a metal wire mesh, preferably a stainless steel wire mesh with a relatively high strength. The first electrode 12 and the second electrode 13 are preferably arranged in parallel and approximately perpendicular to the flow direction of the target fluid.

[0023] The aperture ratio of the first electrode 12 and the second electrode 13 is preferably 15% to 80%, more preferably 20% to 65%, and even more preferably 25% to 50%. This makes it possible to apply a pressure difference to the target fluid by ensuring a contact area between the first electrode 12 and the target fluid while suppressing an increase in flow path resistance due to the first electrode 12. In addition, the first electrode 12 and the second electrode 13 may have large openings or gaps in parts to facilitate the flow of the target fluid. As a specific example, the first electrode 12 may be a mesh-like material with openings formed therein. The first electrode 12 and the second electrode 13 may have different aperture ratios, etc.

[0024] The separation distance in the flow path direction between the first electrode 12 and the second electrode 13 and the connecting member 20 depends on the voltage applied to the first electrode 12 and the second electrode 13, but can be, for example, more than twice the distance between the first electrode 12 and the second electrode 13, specifically more than 10 mm.

[0025] The casing portion 14 extends forward and backward in the flow path direction, and by ensuring a distance between the connecting member 20, which may contain metal, and the first electrode 12 and the second electrode 13, it is possible to form an ideal electric field in the action flow path 111 by the first electrode 12 and the second electrode 13 without being affected by the connecting member 20. For this reason, the casing portion 14 defines flow paths in front of and behind the action flow path 111 that have a larger cross-sectional area and smaller flow path resistance than the action flow path 111.

[0026] The casing 14 has a wiring hole 141 through which a wiring member for connecting the first electrode 12 and the second electrode 13 to a power source (not shown) penetrates. The wiring hole 141 may be sealed with a sealant or the like to prevent leakage of the target fluid, or a sealing structure may be provided in the wiring member or the action part 11 to prevent leakage of the target fluid.

[0027] The fixed structure 15 is preferably made of an insulating material so as not to affect the electric field formed in the working flow path 111. Moreover, the fixed structure 15 is preferably formed integrally with the casing portion 14 in order to minimize the length of the pump module 10. This allows the electrohydrodynamic pump 1 having the desired characteristics to be configured in a relatively small size.

[0028] It is preferable that the fixing structure 15, together with the connection member 20, constitute a structure similar to a pipe joint, that is, a joint structure for connecting piping. This makes it possible to easily obtain members for connecting the pump modules 10, such as the connection member 20, at low cost, and allows the pump modules 10 to be connected without special knowledge.

[0029] As a specific example, the fixing structure 15 may be, for example, a screw, a flange, or the like, but is preferably a ferrule having a shape defined in ISO 2852. Using a ferrule as the fixing structure 15 enables easy and reliable connection of the pump module 10. Furthermore, using a ferrule as the fixing structure 15 makes it possible to reduce the size of the fixing structure 15 and the amount of protrusion of the connection member 20 toward the first electrode 12 and the second electrode 13, thereby making it possible to reduce the size of the pump module 10.

[0030] The fixing structure 15 is also used to connect the electrohydrodynamic pump 1 to a flow path of the target fluid at both ends of the electrohydrodynamic pump 1. To connect the electrohydrodynamic pump 1 to a flow path that uses a different joint than the fixing structure 15 of the electrohydrodynamic pump 1, an adapter (not shown) may be used that has a joint used for the flow path at one end and a structure similar to that of the fixing structure 15 at the other end. Such an adapter may have a reducer that converts the diameter of the casing 14 to the diameter of the flow path.

[0031] The connection member 20 connects two adjacent pump modules 10 by holding two fixing structures 15 arranged opposite to each other. A member corresponding to the fixing structures 15 is used as the connection member 20. The connection member 20 may be made of metal in order to firmly connect the pump modules 10 together. For example, when the fixing structures 15 are ferrules, a clamp band for ferrules as defined in ISO2852 is used as the connection member 20. The clamp band for ferrules has a small width in the flow path direction, and therefore is less likely to affect the electric field formed in the action flow path 111. If the fixing structures 15 are screws, a socket or union may be used as the connection member 20, and if the fixing structures 15 are flanges, multiple sets of bolts and nuts may be used as the connection member 20.

[0032] A gasket 21 that seals gaps in the pump modules 10 may be interposed between the fixing structures 15 of the two pump modules 10 connected by the connecting member 20. The gasket 21 seals gaps in the pump modules 10. For the gasket 21, a member corresponding to the fixing structures 15 is used. Furthermore, the gasket 21 may be omitted depending on the configurations of the fixing structures 15 and the connecting members 20.

[0033] The electrohydrodynamic pump 1 can be driven by a drive circuit (not shown) that applies voltages individually to the multiple pump modules 10. A constant voltage (on-off control), an adjustable voltage (voltage control), or a high-frequency voltage with an adjustable on-off ratio (duty control) may be applied to each pump module 10. In this way, by adjusting the output of each pump module 10, the electrohydrodynamic pump 1 can obtain a desired discharge flow rate and discharge pressure, and can operate with high energy efficiency regardless of the discharge conditions.

[0034] As described above, the electrohydrodynamic pump 1 is configured by combining a plurality of pump modules 10, so that a variety of specifications can be realized relatively inexpensively by selecting the pump modules 10, and the specifications can also be easily changed. Furthermore, even if the required pump output is changed in the specifications, the pump modules 10 can be easily rearranged, and the pump output can be changed to an appropriate output by simply replacing one or more of the pump modules 10, or adding one or more pump modules 10.

[0035] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be modified as appropriate. [Explanation of symbols]

[0036] 1. Electrohydrodynamic pump 10 Pump Module 11 Acting part 111 Working channel 112,113 Retention structure 114, 115 Retaining member 12 1st electrode 13 Second electrode 14 Casing section 141 Wiring hole 15 Fixed structure 20 Connection member 21 Gasket

Claims

1. 1. An electrohydrodynamic pump that generates a flow in a target fluid having insulating properties by applying a voltage to the target fluid, A plurality of pump modules arranged in series, each of which applies a voltage to the target fluid; A connection member that connects adjacent pump modules to each other; Equipped with Each of the pump modules comprises: An action portion formed of an insulating material and defining an action flow path for applying a voltage to the target fluid; A pair of electrodes for applying an electric field to the action flow path; A cylindrical casing portion formed of an insulating material and accommodating the action portion; a pair of fixing structures provided integrally at both ends of the casing and held by the connecting member; An electrohydrodynamic pump having

2. 2. The electrohydrodynamic pump of claim 1, wherein the stationary structural portion is integrally formed with the casing portion from an insulating material.

3. 3. The electrohydrodynamic pump according to claim 1, wherein the fixed structure and the connecting member form a pipe joint.

4. 4. The electrohydrodynamic pump according to claim 3, wherein the fixing structure is a ferrule and the connecting member is a clamp band.

5. The electrohydrodynamic pump of claim 1 , wherein the plurality of pump modules include pump modules having different shapes of the working flow passages.

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