JPWO2008133100A1 - Diaphragm pump - Google Patents

Abstract

Diaphragm which is flat and vibrates so that the amplitude of the central part becomes the largest; pump chamber formed between the diaphragm and the housing; suction side liquid reservoir chamber provided in the housing at an eccentric symmetry position with respect to the plane center of the diaphragm And a discharge side liquid storage chamber; a suction side reverse that is provided between the pair of liquid storage chambers and the pump chamber, and allows fluid flow from the suction side liquid storage chamber to the pump chamber and does not allow fluid flow in the opposite direction. A check valve, a discharge-side check valve that allows fluid flow from the pump chamber to the discharge-side reservoir, and does not allow fluid flow in the opposite direction; and a suction-side reservoir and discharge-side reservoir that are parallel to each other; In a diaphragm pump having a suction port and a discharge port respectively opened in the chamber, the center distance between the opening end of the suction port to the suction side liquid reservoir chamber and the opening end of the discharge port to the discharge side liquid reservoir chamber is reversed to the suction side. Stop valve and discharge side Larger set than the center spacing of stop valve, reduced the diaphragm pump flow resistance and pressure loss.

Description

  The present invention relates to a diaphragm pump.

  An example of a pump that obtains a pump action by a vibrating diaphragm is a piezoelectric pump. The piezoelectric pump forms a pump chamber by a planar circular piezoelectric vibrator and a housing. The housing is provided with a suction-side liquid storage chamber and a discharge-side liquid storage chamber, each of which is located at an eccentric symmetry position with respect to the plane center of the diaphragm. The suction side check valve that allows fluid flow from the suction side liquid reservoir chamber to the pump chamber and not reverse fluid flow, and permits fluid flow from the pump chamber to the discharge side liquid reservoir chamber. A discharge-side check valve that does not allow fluid flow in the reverse direction is provided. When the volume of the pump chamber increases when the piezoelectric vibrator vibrates, the inflow side check valve opens and the discharge side check valve closes, and the fluid flows into the pump chamber from the suction port and the suction side liquid storage chamber. In the process of reducing the volume of the pump chamber, the discharge-side check valve is opened and the suction-side check valve is closed, and fluid is discharged from the pump chamber to the discharge-side reservoir and discharge port to obtain a pump action.

JP 2006-253477 A JP2003-120548 No. 06-18076

  In this diaphragm pump, in order to ensure a high discharge rate by the displacement of the piezoelectric vibrator (diaphragm), it is expected to reduce the flow path resistance and the pressure loss as much as possible.

  The present invention has a pair of check valves (a suction-side check valve and a discharge-side check valve) and a pair of ports (a suction port and a discharge port) of a conventional diaphragm pump from the viewpoint of minimizing the flow resistance and pressure loss. As a result of reviewing the positional relationship of the port), the circular diaphragm has the largest displacement at the center, but the conventional product has the same distance between the pair of check valves and the distance between the pair of ports (a pair of ports). A pair of check valves is located on the extended line of the port), and the present inventors have reached the conclusion that this is the cause of increasing the flow resistance and the pressure loss.

  The present invention relates to a diaphragm that is circular and vibrates so that the amplitude of the central portion thereof is maximized; a pump chamber formed between the diaphragm and the housing; a suction provided in the housing at an eccentric symmetry position with respect to the plane center of the diaphragm Side liquid storage chamber and discharge side liquid storage chamber; fluid flow from the suction side liquid storage chamber to the pump chamber, which is provided between the pair of liquid storage chambers and the pump chamber, respectively, and reverse fluid flow is allowed. A suction-side check valve, a discharge-side check valve that allows fluid flow from the pump chamber to the discharge-side reservoir and does not allow fluid flow in the opposite direction; and a suction-side reservoir that is parallel to each other; In a diaphragm pump having a suction port and a discharge port that respectively open to the discharge side liquid reservoir chamber, the center distance between the opening end of the suction port to the suction side liquid reservoir chamber and the opening end of the discharge port to the discharge side liquid reservoir chamber is determined. , Suction side check Is characterized broadly that set than the center spacing of the discharge side check valve and.

  The flow path passing through the suction port, suction side liquid reservoir, suction side check valve, pump chamber, discharge side check valve, discharge side liquid reservoir and discharge port is orthogonal to the plane including the axes of the suction port and discharge port. When viewed from the direction to do, it is preferably arranged so as to form a U-shape.

  Each of the suction side and discharge side check valves is preferably composed of an umbrella having a shaft portion and an umbrella portion, and a flow path hole formed around the shaft portion of the umbrella and covered by the umbrella portion. The shafts of the pair of umbrellas on the suction side and the discharge side are preferably non-parallel and symmetrical with respect to the central axis of the diaphragm, and are inclined in a direction toward each other toward the diaphragm.

  The present invention can be applied to a piezoelectric pump using a piezoelectric vibrator as at least a diaphragm.

  In the diaphragm pump of the present invention, the distance between the suction side check valve and the discharge side check valve is set to be smaller than the distance between the suction port and the discharge port with respect to the circular diaphragm having the maximum displacement at the center (a pair of pairs). Since the interval between the ports is set wider than the interval between the pair of check valves), the suction port, the suction side reservoir, the suction side check valve, the center of the pump chamber where the displacement of the diaphragm is maximum, the discharge side check valve, the discharge A smooth flow path can be formed in the order of the side liquid reservoir and the discharge port, and an efficient pump with reduced flow path resistance and pressure loss can be obtained.

It is a disassembled perspective view which shows one Embodiment which applied this invention to the piezoelectric pump. It is the top view drawn except the cover and the piezoelectric vibrator. It is the same side view. It is sectional drawing which follows the IV-IV line of FIG. FIG. 5 is a cross-sectional view drawn from FIG. 4 excluding a piezoelectric vibrator and a check valve unit. It is the graph which investigated the influence which the width of a non-return valve interval has on flow characteristics. It is the graph which investigated the influence which the width of a non-return valve interval has on closing pressure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Piezoelectric vibrator 10a Shim 10b Piezoelectric body 10c Power supply terminal 11 Guide ring 12 O-ring 20 Upper housing 30 Lower housing 31 Circular recess 32 Suction side liquid reservoir chamber 33 Discharge side liquid reservoir chamber 34 Suction port 35 Discharge port 34a 35a Open end 36 Suction-side umbrella 37 Discharge-side umbrella 40 Drive substrate 50 Lower lid P Pump chamber

  1 to 5 show an embodiment in which the present invention is applied to a piezoelectric pump. The piezoelectric pump 100 includes a planar circular piezoelectric vibrator 10, an upper housing (upper lid) 20, a lower housing 30, a drive substrate 40, and a lower lid 50. The lower housing 30 is formed with a circular recess 31 that receives the piezoelectric vibrator 10. The piezoelectric vibrator 10 accommodated in the circular recess 31 is sandwiched between the upper housing 20 and the lower housing 30 with the guide ring 11 and the O-ring 12 in contact with the front and back surfaces thereof, and the pump chamber P ( 4).

  As shown in FIGS. 1 and 4, the piezoelectric vibrator 10 is a unimorph type including a shim 10a facing the pump chamber P side and a piezoelectric body 10b facing the atmosphere chamber (upper housing 20) side. The shim 10a is made of a conductive metal thin plate material, for example, a thin plate such as stainless steel having a thickness of about 50 μm or 42 alloy. The piezoelectric body 10b is made of a piezoelectric material such as PZT (Pb (Zr, Ti) O3) having a thickness of about 50 to 300 [mu] m, for example, and is polarized in the front and back directions. Such a piezoelectric vibrator is well known. Electrodes are formed on the front and back sides of the piezoelectric body 10b. By applying an alternating electric field between the front and back electrodes via the power supply terminal 10c (FIG. 1) and the drive substrate 40, the piezoelectric vibrator 10 is It vibrates so that the amplitude of the central portion of the planar circle becomes the largest.

  In the lower housing 30, a suction side liquid storage chamber 32 and a discharge side liquid storage chamber 33 are formed in a circular recess 31 so as to be positioned at an eccentric symmetry position with respect to the plane center of the piezoelectric vibrator 10 (circular recess 31). Yes. The lower housing 30 is formed with a suction port 34 and a discharge port 35 communicating with the suction-side liquid reservoir chamber 32 and the discharge-side liquid reservoir chamber 33. The suction port 34 and the discharge port 35 are parallel to each other and protrude from one side surface of the lower housing 30. Reference numerals 34a and 35a denote opening ends of the suction port 34 and the discharge port 35 with respect to the suction-side liquid reservoir chamber 32 and the discharge-side liquid reservoir chamber 33, which are eccentric to the side away from the center of the piezoelectric vibrator 10 (circular recess 31). The suction side liquid reservoir chamber 32 and the discharge side liquid reservoir chamber 33 are opened.

  Between the suction side liquid reservoir chamber 32 and the pump chamber P, and between the discharge side liquid reservoir chamber 33 and the pump chamber P, a suction side umbrella (suction side check valve) 36 and a discharge side umbrella (discharge side check valve), respectively. ) 37 is provided. The suction-side umbrella 36 is a suction-side check valve that allows a fluid flow from the suction-side liquid reservoir chamber 32 to the pump chamber P and does not allow the reverse fluid flow. The discharge-side umbrella 37 discharges from the pump chamber P. This is a discharge-side check valve that allows fluid flow to the side liquid storage chamber 33 but not vice versa. The suction-side and discharge-side umbrellas 36 and 37 are in symmetrical positions that are decentered with respect to the planar center of the planar circular piezoelectric vibrator 10.

  The suction-side and discharge-side umbrellas 36 and 37 have the same (symmetric) structure, and include planar circular umbrella portions 36a and 37a and shaft portions 36b and 37b at the centers of the umbrella portions. The valve seat substrates 36c and 37c are provided with shaft holes 36d and 37d for receiving and supporting the shaft portions 36b and 37b and flow passage holes 36e and 37e positioned around the shaft holes 36d and 37d. These channel holes 36e and 37e are covered with umbrella portions 36a and 37a.

  The axes of the suction-side umbrella 36 (shaft portion 36b) and the discharge-side umbrella 37 (shaft portion 37b) are not parallel to the axis of the piezoelectric vibrator 10 and are inclined toward the piezoelectric vibrator 10 toward each other. (Fig. 4). In other words, the umbrella portions 36 a and 37 a of the intake side and discharge side umbrellas 36 and 37 in the valve-closed state are non-parallel to the piezoelectric vibrator 10 in the inactive state.

  As shown in FIG. 2, the suction-side umbrella 36 (shaft portion 36 b) and the discharge-side umbrella 37 (shaft portion 37 b) have a center distance d such that the opening end 34 a of the suction port 34 and the opening end 35 a of the discharge port 35. Is set to be shorter than the center distance D. As a result, the suction port 34 (opening end 34a), the suction side liquid reservoir chamber 32, the suction side umbrella 36, the pump chamber P, the discharge side umbrella 37, the discharge side liquid reservoir chamber 33, and the discharge port 35 (open end 35a) are passed. The flow path is U-shaped when viewed from a direction orthogonal to a plane including the axis of the suction port 34 and the discharge port 35. The wall surface of the suction-side liquid reservoir chamber 32 where the extension line of the suction port 34 collides and the wall surface of the discharge-side liquid reservoir chamber 33 where the extension line of the discharge port 35 hit each constitute a smooth U-shaped flow path. It consists of approximately a quarter cylindrical surface.

  In the above-described piezoelectric pump, when the piezoelectric vibrator 10 is elastically deformed (vibrated) in the forward and reverse directions, the umbrella portion 36a of the suction-side umbrella 36 is elastically moved away from the valve seat substrate 36c in the process of expanding the volume of the pump chamber P. Since the flow passage hole 36e is deformed and the umbrella portion 36a of the discharge-side umbrella 36 is in close contact with the valve seat substrate 36c to close the flow passage hole 36e, the suction port 34 and the suction-side liquid reservoir chamber 32 are connected to the inside of the pump chamber P. Liquid flows into the. On the other hand, in the process of reducing the volume of the pump chamber P, the umbrella portion 36a of the discharge-side umbrella 36 opens the flow path hole 36e, and the umbrella portion 36a of the suction-side umbrella 36 closes the flow path hole 36e. The liquid flows out to the discharge side liquid storage chamber 33 and the discharge port 35. Accordingly, the pump action can be obtained by elastically deforming (vibrating) the piezoelectric vibrator 10 continuously in the forward and reverse directions.

  In the piezoelectric pump of this embodiment, the center distance D between the opening end 34 a of the suction port 34 and the opening end 35 a of the discharge port 35 is larger than the center distance d between the suction side umbrella 36 and the discharge side umbrella 37. For this reason, when the piezoelectric vibrator 10 having the largest deformation amount in the center portion vibrates, a smooth flow path is formed from the periphery of the piezoelectric vibrator 10 to the center and from the center to the periphery. This effect can be easily understood by assuming that the center distance D is smaller than or equal to the center distance d (conventional example). In this assumption, it is difficult to obtain a smooth fluid flow, and flow path resistance and pressure loss are large.

  The flow path is also smoothed by the fact that the axes of the suction-side and discharge-side umbrellas 36 and 37 are inclined toward each other toward the piezoelectric vibrator 10. Further, since the umbrella portions 36a and 37a of the suction side and discharge side umbrellas 36 and 37 in the closed state are not parallel to the piezoelectric vibrator 10 in the resting state, the umbrella parts 36a and 37a are in the resting state. 10 does not come into contact, and even if the operation is stopped for a long period of time, there is no possibility of causing an adhesion phenomenon.

  The effect by this embodiment appears notably when the drive frequency of the piezoelectric vibrator 10 becomes high. FIG. 6 shows a piezoelectric pump according to an embodiment of the present invention in which the diameter of the shim 10 is 26 mm, the thickness is 0.15 mm, the center distance d = 10 mm, and the center distance D = 16 mm (D> d). A piezoelectric pump in a comparative example with a thickness of 0.15 mm and a center distance d and D of 10 mm (D = d) was created, and a unit time with respect to the driving frequency (Hz) of the piezoelectric body 10b with a load of 10 kP and a driving voltage of 120 V The flow rate per unit is measured as ml / min. According to this comparative experiment, it can be seen that at D = d, the flow rate increases in all frequency regions except the region of the drive frequency of 50 to 60 Hz. Further, it can be seen that the peak of the flow rate is significantly increased to 232 ml / min in the example, while the comparative example is 189 ml / min.

  Next, FIG. 7 compares the closing pressure with respect to the drive frequency of each piezoelectric pump using the same piezoelectric pump as the said Example and a comparative example. According to FIG. 7, it can be seen that the closing pressure of the example exceeds the closing pressure of the comparative example at all driving frequencies of 30 to 120 Hz.

  In the unimorph type piezoelectric vibrator 10 of the above embodiment, the piezoelectric body 102 is laminated on the surface opposite to the pump chamber P. However, in principle, the piezoelectric body 10b may be laminated on the pump chamber P side. Good. Further, a bimorph type in which the piezoelectric bodies 10b are stacked on both sides of the shim 10a, or a multimorph type in which a plurality of piezoelectric bodies 10b are stacked on the opposite side of the pump chamber P of the shim 10a may be used. However, if the piezoelectric body 102 is laminated on the surface opposite to the pump chamber P, there is no risk of the liquid touching the piezoelectric body 10b, which is preferable for feeding liquids such as corrosive liquids and aqueous solutions. In addition, when the piezoelectric body 10b is laminated on the pump chamber P side, the piezoelectric body 10b can be covered with a protective film or the like to prevent direct contact between the liquid and the piezoelectric body 10b. The liquid may be permeable to moisture. From this viewpoint, it is preferable to laminate the piezoelectric body 10b on the side opposite to the pump chamber P.

  The diaphragm pump of the present invention can be applied to at least a piezoelectric pump, and the piezoelectric pump can be used as a small pump, for example, in a water cooling system of a notebook PC.

Claims (5)

Diaphragm that is flat and oscillates so that its center part has the largest amplitude;
A pump chamber formed between the diaphragm and the housing;
A suction-side liquid storage chamber and a discharge-side liquid storage chamber provided in the housing at a position that is eccentrically symmetric with respect to the plane center of the diaphragm;
A suction-side check valve provided between the pair of liquid reservoir chambers and the pump chamber, allowing a fluid flow from the suction-side liquid reservoir chamber to the pump chamber and not allowing a fluid flow in the opposite direction; and a pump chamber A discharge-side check valve that allows fluid flow to the discharge-side reservoir and does not allow fluid flow in the opposite direction; and is parallel to each other and opens to the suction-side reservoir and the discharge-side reservoir, respectively. A diaphragm pump having a suction port and a discharge port;
The center distance between the opening end of the suction port to the suction side liquid reservoir and the opening end of the discharge port to the discharge side liquid reservoir is set wider than the center distance between the suction side check valve and the discharge side check valve. Diaphragm pump characterized by In the diaphragm pump according to claim 1, the flow path passing through the suction port, the suction side liquid reservoir chamber, the suction side check valve, the pump chamber, the discharge side check valve, the discharge side liquid reservoir chamber and the discharge port includes: A diaphragm pump having a U-shape when viewed from a direction perpendicular to a plane including the suction port and discharge port axes. The diaphragm pump according to claim 1 or 2, wherein the check valves on the suction side and the discharge side are each formed with an umbrella having a shaft portion and an umbrella portion, and are formed around the shaft portion of the umbrella and covered with the umbrella portion. A diaphragm pump having a flow path hole. The diaphragm pump according to any one of claims 1 to 3, wherein the shaft portions of the pair of suction side and discharge side umbrellas are non-parallel to a central axis of the diaphragm and approach each other toward the diaphragm. Diaphragm pump that is inclined in the direction of The diaphragm pump according to any one of claims 1 to 4, wherein the diaphragm is a piezoelectric vibrator.

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