JP2018123796A - Micro diaphragm pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology that enables increase in the supply amount or the like in a diaphragm pump.SOLUTION: A micro diaphragm pump 10 includes: a valve plate 30 having suction valves 31a, 31b and discharge valves 32a, 32b; a diaphragm 40 which forms chambers 80a, 80b by one surface being arranged so that the one surface faces the valve plate 30; piezoelectric elements 60a, 60b bonded to the diaphragm 40; and driving circuits 65a, 65b which apply voltage to the piezoelectric elements. The piezoelectric element 60a is disposed facing a valve plate part 30a formed by the suction valve 31a and the discharge valve 32a, and the piezoelectric element 60b is disposed facing a valve plate part 30b formed by the suction valve 31b and the discharge valve 32b.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a micro-diaphragm pump formed by laminating a thin film or the like to be a diaphragm.

In recent years, the spread and commercialization of fuel cell systems are expected as a distributed energy plant for home use (for detached houses). This type of fuel cell requires a pump for supplying fuel gas, liquid fuel, water supplied to the reformer, hydrogen produced by the reformer, and the like to the fuel cell itself. Carbon monoxide (CO) is generated during reforming to extract the necessary hydrogen (H ₂ ) from the fuel. This carbon monoxide adversely affects the performance of the cell catalyst, so it is selected to reduce the carbon monoxide concentration. Control of the flow rate of oxidizing air is also required at the same time. Furthermore, analytical devices and medical care (medicine, clinical trials, etc.) require the supply of very small amounts of gas or liquid. Furthermore, a small pump for releasing and cooling the heat generated with the performance improvement of the electronic device is also required.

  Various micropumps used for such applications have been proposed so far. As a general pump, a centrifugal type, a volume rotary type, a volume reciprocating type, and the like are well known. The volume reciprocating type has features such as discharge of minute flow rate and good lightweight accuracy. Especially the diaphragm type is suitable for downsizing, so medical equipment that can be implanted in the body, small analytical equipment, office equipment, etc. Has been applied.

  Patent Documents 1 to 3 disclose micro diaphragm pumps driven by piezoelectric elements. In these disclosed pumps, a diaphragm is joined to a valve seat in which a suction valve and a discharge valve are formed via a frame made of one frame plate or a plurality of frame plates. A valve seat having a suction valve and a discharge valve faces one surface of the diaphragm, and one piezoelectric element (piezo element) that vibrates the diaphragm is attached to the other surface. A pressure chamber whose volume (internal pressure) is changed by vibration of the diaphragm is formed in a space surrounded by the diaphragm, the valve seat, and the frame plate (or frame).

Japanese Patent No. 4945661 JP 2011-117211 A JP 2011-117212 A

  However, in the conventional micro diaphragm pump described above, the fluid is supplied by one piezoelectric element, and the supply amount is limited. For this reason, in recent years, it has been strongly desired to provide a micro-diaphragm pump that can increase the supply amount while supplying a very small amount.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a technique such as increasing the pump supply amount by arranging a plurality of piezoelectric elements in a micropump having a diaphragm. Yes.

  In order to solve the above-described problems, the present invention is affixed to a valve plate having a suction valve and a discharge valve, a diaphragm that forms a chamber by placing one surface thereof facing the valve plate, and the other surface of the diaphragm. And a drive circuit for applying a voltage to the piezoelectric element, wherein the valve plate includes a plurality of valve plate portions each including an intake valve and a discharge valve, and the piezoelectric element A plurality of valve plate portions are provided to be opposed to each other.

  In the micro-diaphragm pump having the above-described configuration, a suction-side communication channel that allows the suction ports of the plurality of suction valves in the valve plate to communicate with each other and a discharge-side communication channel that allows the discharge ports of the plurality of discharge valves to communicate with each other. It is preferable to provide a communication channel sheet having the same.

  Further, the suction valves and the discharge valves are alternately arranged side by side, and the suction side communication flow path and the discharge side communication flow path are respectively formed in an arch shape so as to bypass the discharge port or the suction port. Is preferred.

  And a communication flow path sheet in which a discharge flow path of the discharge valve in the valve plate portion and a suction port of the suction valve in the other valve plate portion are communicated with each other to form a relay flow path for relaying discharge and suction. preferable.

The drive circuit preferably applies an alternating voltage having the same phase or different phases to each of the plurality of piezoelectric elements.
It is preferable that the alternating voltages having different phases are alternating voltages in which the opposite directions are reversed.

  According to the micro diaphragm pump of the present invention, the pump supply amount can be increased by arranging a plurality of piezoelectric elements.

It is an external appearance perspective view of the micro diaphragm pump by Example 1 of this invention. It is a disassembled perspective view for demonstrating the laminated structure of the pump of FIG. It is a schematic cross section of the pump of FIG. It is a figure which shows the opening pattern of a valve seat. It is sectional drawing of the valve seat cut | disconnected by the VV line shown in FIG. It is a figure which shows the opening pattern of a valve seat. It is sectional drawing of the valve-seat sheet | seat cut | disconnected by the VII-VII line shown in FIG. It is a top view which shows the structure of a communication flow path sheet. It is a figure which shows the applied voltage of a drive circuit. It is another figure which shows the applied voltage of a drive circuit. It is a disassembled perspective view for demonstrating the laminated structure of the micro diaphragm pump by Example 2 of this invention. It is a schematic cross section of the pump of FIG. It is a top view which shows the communication flow path sheet | seat of FIG.

  A preferred embodiment of a micro diaphragm pump according to the present invention will be described. In the following description, the terms “upper”, “lower”, “left”, and “right” simply mean relative positional relationships, and are not interpreted in the meaning of absolute directions. A micro-diaphragm pump according to an embodiment of the present invention includes a valve plate having an intake valve and a discharge valve, a diaphragm having one surface opposed to the valve plate, a piezoelectric element attached to the other surface of the diaphragm, and a piezoelectric element A drive circuit for applying an alternating voltage.

  The valve plate according to one embodiment includes a first valve plate portion and a second valve plate portion arranged side by side, and each of the first valve plate portion and the second valve plate portion includes one set. It has a suction valve and a discharge valve, and they have a symmetrical structure.

  That is, the first valve plate portion includes a first suction valve and a first discharge valve, and the second valve plate portion includes a second suction valve and a second discharge valve. These intake valves and discharge valves are alternately arranged along a straight line in the order of the first intake valve, the first discharge valve, the second intake valve, and the second discharge valve.

  The piezoelectric element includes a first piezoelectric element and a second piezoelectric element, and each piezoelectric element is disposed to face each valve plate portion with a diaphragm interposed therebetween. The first piezoelectric element is disposed to face the first valve plate portion, and the second piezoelectric element is disposed to face the second valve plate portion.

  The drive circuit includes a first drive circuit and a second drive circuit, and each drive circuit applies an alternating voltage with the same phase or a different phase to each piezoelectric element or supplies an alternating current to each piezoelectric element. be able to. For example, the first drive circuit can apply an alternating voltage to the first piezoelectric element, and the second drive circuit can apply the alternating voltage to the second piezoelectric element. When an alternating voltage having the same phase is applied to each piezoelectric element or an alternating current having the same phase is supplied, one drive circuit may be provided.

  The micro diaphragm pump is configured to guide the fluid in each chamber from the suction valve to the discharge valve by applying an alternating voltage to each piezoelectric element or supplying an alternating current to vibrate the corresponding diaphragm. .

  As a piezoelectric element (piezo element) that vibrates the diaphragm, for example, a sintered body generally called PZT containing zircon / lead titanate can be adopted. As a material for the diaphragm, for example, a stainless steel thin plate (SUS sheet) that is resistant to corrosion by the fluid used can be employed. In addition, a thin plate here contains a foil-shaped thing.

  FIG. 1 is an external perspective view of a micro diaphragm pump 10 according to an embodiment of the present invention. FIG. 2 is an exploded perspective view for explaining the laminated structure of the pump 10. FIG. 3 is a schematic cross-sectional view of the pump 10. The micro-diaphragm pump 10 is formed by stacking a plurality of stainless steel thin plates and a frame body in a multi-layered manner, that is, by aligning and laminating metal thin plates and the like, and joining them. The main body of the pump 10 of this embodiment is a quadrangle having a short side of about 7 mm and a long side of about 14 mm, and its thickness is 1 mm or less. In this embodiment, nine stainless thin plates (SUS sheets) are collectively diffusion bonded (bonded by heating and pressing in a vacuum) to form one metal laminate.

  This laminated body is comprised from the bottom from the base plate 20, the communication flow path sheet 25, the valve plate 30, the inner frame body 37, the diaphragm sheet 40, and the outer frame body 50. The valve plate 30 includes a plurality of seat members including a lower valve seat 34L, a lower valve seat 35L, an upper valve seat 35U, and an upper valve seat 34U.

  The valve plate 30 constitutes a first valve plate portion 30a and a second valve plate 30b. The first valve plate portion 30a includes a first lower valve seat portion 34La, a first lower valve seat portion 35La, a first upper valve seat portion 35Ua, and a first upper valve seat portion 34Ua. Is done. The second valve plate portion 30b includes a first lower valve seat portion 34Lb, a first lower valve seat portion 35Lb, a second upper valve seat portion 35Ub, and a second upper valve seat portion 34Ub. Is done.

  The base plate 20 is a stainless steel plate having a short side of about 7 mm and a long side of about 14 mm, and is formed with a suction port channel 21 and a discharge port channel 22 passing therethrough. On the base plate 20, the lower valve seat sheet 34L, the lower valve seat 35L, the upper valve seat 35U, and the upper valve seat sheet 34U are laminated in this order via the communication flow path sheet 25. A laminated body of the valve plates 30 is formed by diffusion bonding. A laminated body (preliminary laminated body) of the valve plate 30 may be formed in advance, and the valve plate laminated body may be joined to the base plate 20 later.

  Next, the valve seats 35U and 35L will be described. The two valve seats 35U and 35L shown in FIGS. 2 and 3 are in a relationship in which the same valve seat is simply reversed left and right. Here, the valve seat 35U will be described as a representative with reference to FIGS. FIG. 4 shows an opening pattern of the valve seat 35U. FIG. 5 shows a cross-sectional view of the valve seat 35U when cut along the line V-V shown in FIG. The valve seat 35U is made of a stainless steel plate having the same outer shape as the base plate 20. In the valve seat 35U, valve plates 351Ua and 351Ub and flow path openings 352Ua and 352Ub are formed by etching or press punching. Here, the valve plates 351Ua and 351Ub are supported by support arms 3512Ua and 3512Ub extending from the valve plate openings 3511Ua and 3511Ub having substantially the same diameter as the flow path openings 352Ua and 352Ub while bending toward the inner diameter side.

  Next, the valve seats 34U and 34L will be described. The two valve seats 34U and 34L are in a relationship in which the same valve seat is reversed left and right and turned upside down. Here, the valve seat 34U will be described as a representative with reference to FIGS. FIG. 6 shows an opening pattern of the valve seat 34U. FIG. 7 is a cross-sectional view taken along the line VII-VII shown in FIG. The valve seat 34U is formed of a stainless steel plate having the same outer shape as the base plate 20 and the valve seats 35U and 35L, and valve seats 341Ua and 341Ub and valve stoppers 342Ua and 342Ub are formed by etching or press punching.

  The valve seats 341Ua and 341Ub have circular openings 3411a and 3411b serving as flow paths, and annular protrusions 3412a and 3412b along the periphery of the opening. The half-etched regions 3413a and 3413b can be formed to be slightly dented by half-etching (removing to a predetermined depth by etching) around the protrusions 3412a and 3412b. The width in the radial direction of the half-etched regions 3413a and 3413b corresponds to the length from the ridges 3412a and 3412b to the ends of the flow passage openings 352Ua and 352Ub of the opposing valve seat 35U.

  It is preferable to form a DLC (diamond-like carbon) film on the protrusions 3412a and 3412b. The DLC can be formed, for example, by a physical method (PVD) such as vacuum deposition or sputtering, or a chemical method (vapor phase growth method) such as plasma CVD. At this time, areas other than the protrusions 3412a and 3412b are masked to prevent film formation. Further, when forming the half-etched regions 3413a and 3413b, it is desirable to perform masking so that at least the protrusions 3412a and 3412b are not etched.

  The valve stoppers 342Ua and 342Ub are divided into three circumferential sections around the openings 3423a and 3423b, the annular portions 3421a and 3421b formed at the edges of the openings 3423a and 3423b, and the annular portions 3421a and 3421b, respectively. Channels 3422a, 3422a, 3422a, 3422b, 3422b, and 3422b. The annular portions 3421a and 3421b are portions that contact the valve plates 351Ua and 351Ub. Therefore, the inner diameters of the openings 3423a and 3423b are formed smaller than the outer diameters of the valve plates 351Ua and 351Ub.

  In the correctly aligned valve plate 30, on the suction port side, the valve plates 351La and 351Lb of the valve seat 35L are concentrically installed with the valve seats 341La and 341Lb of the valve seat 34L, and the valve of the valve seat 34U It faces the stoppers 342Ua and 342Ub. As a result, intake valves 31a and 31b are formed.

  On the discharge port side, the valve plates 351Ua and 351Ub of the valve seat 35U are installed concentrically with the valve seats 341Ua and 341Ub of the valve seat 34U, and face the valve stoppers 342La and 342Lb of the valve seat 34L. Thus, the discharge valves 32a and 32b are formed.

  Next, the inner frame 37 is made of a stainless steel plate having the same outer shape as the diaphragm sheet 40. In the inner frame 37, openings 37a and 37b punched in a circular shape corresponding to the movable range of the diaphragm sheet 40 are formed at symmetrical positions on the left and right.

  Similarly to the inner frame body 37, the outer frame body 50 is also made of a stainless steel plate having the same outer shape as the diaphragm sheet 40. Similarly, the outer frame body 50 has openings 50a and 50b punched in a circular shape corresponding to the movable range of the diaphragm sheet 40 at symmetrical positions.

  As shown in FIG. 8, a suction side communication channel 251 and a discharge side communication channel 252 are punched and formed in the communication channel sheet 25. The suction side communication channel 251 connects the suction port (opening portion of the valve seat 341La) of the first suction valve 31a and the suction port (opening portion of the valve seat 341Lb) of the second suction valve 31b to each other in the valve plate 30. Communicate with. The right end side 251 a of the suction side communication channel 251 further communicates with the suction port channel 21 of the base plate 20. The discharge side communication channel 252 allows the discharge port of the first discharge valve 32a (opening portion of the valve stopper 342La) and the discharge port of the second discharge valve 32b (opening portion of the valve stopper 342Lb) to communicate with each other. . The left end side 252 b of the discharge side communication flow path 252 further communicates with the discharge port flow path 22 of the base plate 20.

  As described above, in the present embodiment, the first suction valve 31a, the first discharge valve 32a, the second suction valve 31b, and the second discharge valve 32b are arranged along a single straight line. The suction side communication channel 251 bypasses the discharge port of the first discharge valve 32a, and the discharge side communication channel 252 bypasses the suction port of the second suction valve 31b. It is formed in a smooth arc shape with no corners.

  The micro-diaphragm pump 10 is formed by diffusion bonding a metal laminate including the base plate 20, the communication channel sheet 25, the valve plate 30, the inner frame 37, the diaphragm sheet 40, and the outer frame 50, and then thermosetting. It is formed by applying adhesives 70a and 70b that are conductive resins and sticking PZTs 60a and 60b that are piezoelectric elements to left and right symmetrical positions on the upper surface of the diaphragm sheet 40 (FIG. 3).

When an alternating voltage is applied to the PZTs 60a and 60b from the drive circuits 65a and 65b, the PZTs 60a and 60b expand and contract, and accordingly, tensile and compressive stresses are generated on the surface of the diaphragm 40 and vibrate up and down. In this embodiment, the amplitude of the diaphragm 40 is about 20 μm (± 10 μm). The volume of the chamber 80 changes due to the vertical vibration of the diaphragm 40.
Note that when an alternating voltage having the same phase is applied to the PZTs 60a and 60b, one drive circuit may be provided.

  When the diaphragm 40 is deformed upward and the internal pressure of the chambers 80a and 80b becomes negative, the valve plates of the suction valves 31a and 31b are opened away from the valve seats, and the valve plates of the discharge valves 32a and 32b are opened to the valve seats. Close by hitting. As a result, from the suction port flow path 21 of the base plate 20 to the right end side 251a and the left end side 251b of the suction side communication flow path 251 of the communication flow path sheet 25, the inner frame body 37 passes through the suction valves 31a and 31b. Two parallel suction passages are formed to reach the two chambers 80a and 80b in the openings 37a and 37b.

  By using the suction side communication flow path 251 in this way, the chamber 80a, through the two parallel suction paths above the suction valves 31a and 31b, while keeping the suction port flow path 21 of the base plate 20 as one. Fluid can be sucked into 80b. Since the suction-side communication flow path 251 is formed in a smooth arc shape with an arcuate shape and no corners, the fluid can smoothly flow through the flow path, and pressure loss during flow can be reduced.

  When the diaphragm 40 is deformed downward and the diaphragm 40 pressurizes the chambers 80a and 80b, the valve plates of the suction valves 31a and 31b abut against the valve seat, and the valve plates of the discharge valves 32a and 32b are separated from the valve seat. open. As a result, two discharge channels are formed from the two chambers 80a and 80b through the discharge valves 32a and 32b to the left end side 252b and the right end side 252a of the discharge side communication channel 252 of the communication channel sheet 25. Furthermore, the discharge flow path is formed from the left end side of the discharge side communication flow path 252 to reach the discharge port flow path 22 in which the base plate 20 is arranged in parallel.

Thus, by passing the discharge side communication flow path 252, the discharge port flow path 22 of the base plate 20 is kept as one, and the chamber 80 a, The fluid in 80b can be discharged outside. Therefore, the pump supply amount can be increased as compared with the conventional configuration.
In addition, since the discharge-side communication flow path 252 is formed in a smooth arc shape with an arcuate shape and no corners, the flow of fluid in the flow path is smooth, and the pressure loss during flow can be reduced.

  As shown in FIG. 9, the first drive circuit 65a and the second drive circuit 65b apply alternating voltages having the same phase to the first piezoelectric element 60a and the second piezoelectric element 60b, respectively. The expansion and contraction of the elements 60a and 60b can be synchronized.

  Thereby, the opening / closing operations of the first suction valve 31a and the second suction valve 31b can be synchronized, and the opening / closing operations of the first discharge valve 32a and the second discharge valve 32b can also be synchronized, The suction amount and discharge amount (supply amount) of the micro diaphragm pump 10 can be increased. Note that the suction operation and the discharge operation of the micro diaphragm pump 10 in FIG. 9 are performed alternately, and the discharge operation is an intermittent operation.

  On the other hand, as shown in FIG. 10, the first drive circuit 65a and the second drive circuit 65b apply alternating voltages having different phases to the first piezoelectric element 60a and the second piezoelectric element 60b, respectively. Accordingly, the piezoelectric elements 60a and 60b can expand and contract at different timings, and the opening and closing operations of the first suction valve 31a and the second suction valve 31b can be set at different timings, and the first discharge valve 32a and the second suction valve 32b. The opening / closing operation of the discharge valve 32b can also be at different timings.

  Thus, the suction operation and the discharge operation of the micro diaphragm pump 10 can be performed in an overlapping manner, and the suction operation and the discharge operation can be made continuous. Further, the flow rate per unit time during the flow of the suction port flow channel 21 and the discharge port flow channel 22 can be reduced, and the pressure loss of the port flow channels 21 and 22 can be reduced. (Supply amount) can be further increased.

  Here, as shown in FIG. 10, the alternating voltages having different phases are alternating voltages in which the forward and reverse are reversed, and the suction operation and the discharge operation are surely continuous. It becomes possible.

  FIG. 11 is an exploded perspective view of the micro diaphragm pump 11 according to the second embodiment of the present invention. FIG. 12 is a schematic cross-sectional view of the pump 11. In these drawings, elements that are the same as or correspond to those in the above-described embodiment are given the same reference numerals as those elements.

  The micro diaphragm pump 11 of Example 2 is obtained by changing the communication channel sheet of Example 1 to the communication channel sheet 26 shown in FIG. In the communication flow path sheet 26 of the second embodiment, a suction port 261, a discharge hole 262, and a relay flow path 263 are formed by punching. The suction port 261 communicates with the suction port channel 21 of the base plate 20 and is formed at a position corresponding to the suction port of the first suction valve 31a (the opening of the valve seat 341La) in the valve plate 30. The discharge hole 262 communicates with the discharge port channel 22 of the base plate 20 and is formed at a position corresponding to the discharge port of the second discharge valve 32b (opening portion of the valve stopper 342Lb). The relay flow path 263 allows the discharge port of the first discharge valve 32a (the opening of the valve stopper 342La) and the suction port of the second suction valve 31b (the opening of the valve seat 341Lb) to communicate with each other.

By employing such a communication flow path sheet 26, the piezoelectric elements 60a and 60b are expanded and contracted, so that the suction hole 261 of the communication flow path sheet 26 from the suction port flow path 21 of the base plate 20, the first suction valve. 31a, first chamber 80a, first discharge valve 32a, right end side 263a of relay flow path 263, left end side 263b of relay flow path 263, second suction valve 31b, second chamber 80b, second discharge One serial flow path is formed from the valve 32 b, the discharge hole 262 of the communication flow path sheet 26, and the discharge port flow path 22 of the base plate 20.
Thus, by connecting the valve plate portions 30a and 30b in series, the back pressure of the micro diaphragm pump 11 can be increased as compared with the conventional configuration.

  Also in the second embodiment, the drive circuits 65a and 65b can apply to the piezoelectric elements 60a and 60b alternating voltages having the same phase, alternating voltages having different phases, and alternating voltages in which the forward and reverse are reversed. It is.

10, 11 Micro diaphragm pump 20 Base plate 21 Suction port flow path 22 Discharge port flow path 25, 26 Communication flow path sheet 30 Valve plate 30a, 30b Valve plate portion 31a, 31b Suction valve 32a, 32b Discharge valve 34U, 34L Valve seat Seat 35U, 35L Valve seat 37 Inner frame 40 Diaphragm sheet 50 Outer frame 60a, 60b PZT (piezoelectric element)
65a, 65b Drive circuit 70 Adhesive 80a, 80b Chamber 341Ua, 341Ub, 341La, 341Lb Valve seat 342Ua, 342Ub, 342La, 342Lb Valve stopper 351Ua, 351Ub, 351La, 351Lb Valve plate 352Ua, 352Lb35

Claims (6)

A valve plate having a suction valve and a discharge valve, a diaphragm that forms a chamber by placing one surface opposite the valve plate, a piezoelectric element that is adhered to the other surface of the diaphragm, and a voltage applied to the piezoelectric element A micro-diaphragm pump comprising:
The micro-diaphragm pump, wherein the valve plate includes a plurality of valve plate portions each including an intake valve and a discharge valve, and a plurality of the piezoelectric elements are disposed to face each of the plurality of valve plate portions.   Providing a communication channel sheet having a suction side communication channel for communicating the suction ports of the plurality of suction valves in the valve plate with each other and a discharge side communication channel for communicating the discharge ports of the plurality of discharge valves with each other; The micro diaphragm pump according to claim 1.   The suction valve and the discharge valve are alternately arranged, and the suction side communication channel and the discharge side communication channel are each formed in an arc shape so as to bypass the discharge port or the suction port. The micro diaphragm pump according to claim 1 or 2.   2. A communication flow path sheet having a relay flow path for relaying discharge and suction by allowing a discharge port of a discharge valve in the valve plate portion and a suction port of a suction valve in another valve plate portion to communicate with each other. The micro diaphragm pump described in 1.   5. The micro diaphragm pump according to claim 1, wherein the drive circuit applies alternating voltages having the same phase or different phases to each of the plurality of piezoelectric elements. 6.   The micro-diaphragm pump according to any one of claims 1 to 5, wherein the alternating voltages having different phases are alternating voltages having a relationship in which forward and reverse are reversed.

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