CN101240790A - A valveless piezoelectric pump - Google Patents

Abstract

A valveless piezoelectric pump belongs to piezoelectric pumps. It consists of a cylindrical upper cover, a cylindrical lower cover, a ring elastic gasket, and a piezoelectric vibrator with a bracket. It adopts the piezoelectric vibrator cantilever support method, which realizes the purpose that the drive and flow direction control are completed by common components, thereby saving a lot of components and space, and is conducive to further miniaturization of the pump. According to the specific shape of the piezoelectric vibrator, two layout methods are adopted: one is planar layout, and the other is spatial layout.

Description

A valveless piezoelectric pump

technical field

The invention relates to a cantilever piezoelectric vibrator valveless piezoelectric pump, which belongs to the field of fluid machinery.

Background technique

The classification of pumps can be roughly divided into: positive displacement pumps and rotary pumps. At present, most piezoelectric pumps are positive displacement pumps. According to the presence or absence of pump valves, piezoelectric pumps are divided into valved piezoelectric pumps and valveless piezoelectric pumps. Figure 1 shows a valved piezoelectric pump.

Because the valveless piezoelectric pump omits the complex action valve body, the structure of the piezoelectric pump is simpler, the processing is easy, and it is easy to develop in the direction of miniaturization of the piezoelectric pump; the valveless piezoelectric pump itself has no chemical and electromagnetic Pollution, so it has broad application prospects in the fields of medical treatment, sanitation, and health care.

The piezoelectric vibrator support of the valveless piezoelectric pump mostly adopts the mode that the metal substrate is fixed by the periphery, and a typical one is the conical flow tube valveless piezoelectric pump. Figure 2 shows the conical flow tube valveless piezoelectric pump. However, the surrounding fixed support limits the deformation ability of the piezoelectric vibrator; and the exposed two conical tubes of the pump increase the overall size of the pump, which is not conducive to the further miniaturization and integration of the pump; at the same time, the two conical flow tubes The processing of the tube is difficult, the installation and positioning are not good, and the flow rate of the conical flow tube valveless piezoelectric pump is also small. These defects have seriously affected the application of the piezoelectric pump in the practical field. Moreover, the existing valveless piezoelectric pumps also use the inverse piezoelectric effect of piezoelectric ceramics to realize the driving power source function, and the tapered flow tube realizes the valveless one-way flow function. That is to say: the existing valveless piezoelectric pump type belongs to the separate components of the drive and flow direction to realize the pump.

Contents of the invention

The purpose of the present invention is to overcome the above defects of the valveless piezoelectric pump, to provide a cantilever piezoelectric vibrator drive and flow direction that can further reduce the volume and structure size, increase the flow rate of the pump, and has better flow characteristics. The common parts realize the pump, which does not belong to positive displacement classification pumps nor to rotary classification pumps.

There are two structural forms of the valveless piezoelectric pump to achieve the above purpose:

1. A valveless piezoelectric pump, comprising a pump body and a piezoelectric vibrator, is characterized in that it also includes an annular elastic gasket, and the pump body is formed by connecting a cylindrical upper cover and a cylindrical lower cover; The piezoelectric vibrator is a cantilever piezoelectric vibrator with a bracket, which is pasted on the inner circular step of the cylindrical lower cover. The cantilever piezoelectric vibrator with a bracket includes a bracket and a double-sided piezoelectric vibrator. The double-sided piezoelectric vibrator is fixed On the bracket, a cantilever support structure is formed. The double-sided piezoelectric vibrator is composed of a piezoelectric ceramic sheet and a metal sheet. The two piezoelectric ceramic sheets are respectively pasted on the outer surfaces of both sides of the metal sheet; the ring elastic gasket Placed between the cylindrical upper cover and the cylindrical lower cover, through the bolt holes of the cylindrical upper cover, the bolt holes of the ring elastic gasket and the bolt holes of the cylindrical lower cover, bolt the cylindrical upper cover, the ring elastic gasket It is connected with the cylindrical lower cover; a pump inlet is opened in the center of the cylindrical upper cover; a pump outlet is opened in the center of the cylindrical lower cover.

2. A valveless piezoelectric pump, comprising a pump body and a piezoelectric vibrator, characterized in that it also includes an annular elastic gasket, and the pump body is formed by connecting a cylindrical upper cover and a cylindrical lower cover; The piezoelectric vibrator is a piezoelectric vibrator with a ring bracket, which is pasted on the inner circular step of the cylindrical lower cover. The piezoelectric vibrator with a ring bracket includes a ring bracket and 3 to 10 double-sided piezoelectric vibrators , 3 to 10 double-sided piezoelectric vibrators are evenly installed on the circumference of the ring bracket by columns, forming a three-dimensional cantilever support structure. Each double-sided piezoelectric vibrator is composed of piezoelectric ceramic sheets and metal sheets. The piezoelectric ceramic sheet is pasted on the outer surface of both sides of the metal sheet; the annular elastic gasket is placed between the cylindrical upper cover and the cylindrical lower cover, and passes through the cylindrical upper cover bolt hole and the annular elastic gasket bolt hole and the bolt hole of the cylindrical lower cover, the cylindrical upper cover, the ring elastic gasket and the cylindrical lower cover are connected together by bolts; the center of the cylindrical upper cover has a pump inlet; the cylindrical lower cover A pump outlet is opened in the center of the cover.

The cantilever support structure of the piezoelectric vibrator used in the present invention abandons the traditional fixed support structure around the piezoelectric vibrator. The size of the electric vibrator, as well as making full use of the limited space, arranges the piezoelectric vibrator at different angles to realize the control and adjustment of the flow direction and flow of the liquid in the pump; more importantly: the drive and flow control are controlled by common components Realized, saving a lot of parts and space, this kind of pump is neither a volumetric classification pump nor a rotary classification pump. So that the pump has a broader practical application prospect.

Description of drawings

Figure 1 Schematic diagram of a valved piezoelectric pump.

Fig. 2 Schematic diagram of a valveless piezoelectric pump with conical flow tube.

Figure 3 is a front view of the internal structure of the planar layout of the piezoelectric vibrator.

Fig. 4 A-A partial cross-sectional view of the overall structure of the piezoelectric planar arrangement.

Fig. 5. Top view of the cantilever piezoelectric vibrator with bracket.

Fig. 6 Front view of the cylindrical upper cover.

Fig. 7 B-B sectional view of the cylindrical upper cover.

Figure 8 is the front view of the ring elastic gasket.

Figure 9 C-C sectional view of the ring elastic gasket.

Fig. 10 Front view of cylindrical lower cover.

Figure 11 D-D sectional view of the cylindrical lower cover.

Figure 12 Schematic diagram of a double-sided piezoelectric vibrator.

Fig. 13 Front view of the internal structure of the cantilever piezoelectric vibrator valveless piezoelectric pump.

Figure 14 A-A partial sectional view of the overall structure of the cantilever piezoelectric vibrator valveless piezoelectric pump.

Figure 15. Three-dimensional view of piezoelectric vibrator with ring bracket.

Figure 16 Front view of the ring bracket.

Figure 17 The left view of the ring bracket.

In the figure: 1. Pump body, 2. Piezoelectric vibrator, 3. Suction valve, 4. Discharge valve, 5. Conical flow tube, 6. Bolt holes, 7. Cantilever piezoelectric vibrator with bracket, 8. Cylindrical Shaped upper cover, 9, ring elastic gasket, 10, cylindrical lower cover, 11, pump inlet and outlet, 12, piezoelectric ceramic sheet, 13, metal sheet, 14, piezoelectric vibrator with ring support.

Detailed ways

As shown in Fig. 5, the piezoelectric vibrator of the present invention is supported in a cantilever manner, which can cause a large deflection deformation at the front end of the piezoelectric vibrator while having a lower resonance frequency. The piezoelectric vibrator refers to the combination of the piezoelectric ceramic sheet and the metal sheet bonded together. For the specific shape of the piezoelectric vibrator, there are two arrangements available: one is planar arrangement (as shown in Figures 4 and 5), and the other is spatial arrangement (as shown in Figures 14 and 15). The plane layout is to place the cantilever piezoelectric vibrator vertically in the pump cavity. The spatial arrangement is that a plurality of piezoelectric vibrators are respectively fixed on each column of a circular bracket. The structure of the ring bracket is shown in Figures 16 and 17. The three flat plates protruding from the outer edge of the ring are used to fix the position of the bracket, and each column of the ring bracket is used to fix each piezoelectric vibrator. The structure of the ring support can not only increase the number of piezoelectric vibrators, but also make full use of the space, so that the piezoelectric vibrators act on the fluid at different angles, thereby improving the working efficiency of the valveless pump. In addition, by changing the position of the ring bracket, the working range of the piezoelectric vibrator can be flexibly controlled. At the same time, the orientation, number, length, and width of the piezoelectric vibrator can all become control parameters that affect the flow direction and flow rate of the liquid in the pump, so that the cantilever piezoelectric vibrator valveless piezoelectric pump based on the ring bracket can have a wider range of applications. occasions of use.

The cantilever piezoelectric vibrator valveless piezoelectric pump proposed by the present invention has the overall structure of the planar layout of the piezoelectric vibrator as shown in Figures 3 and 4. It mainly consists of a cylindrical upper cover 8, a cylindrical lower cover 10, and a ring elastic pad. The sheet 9 and the cantilever piezoelectric vibrator 7 with a bracket are composed of four parts. Among them, there are circular holes 11 on the cylindrical upper and lower covers, which are used as pump inlets and outlets. The inner circular steps of the lower cover are used to bond the support of the cantilever piezoelectric vibrator, and the ring elastic gasket 9 is placed on the cylindrical upper and lower. Between the covers, the role of preventing pump leakage is played. The cylindrical upper cover, the annular elastic gasket and the cylindrical lower cover are connected together by six bolts through the surrounding bolt holes 6. The overall structure of the spatial arrangement of the piezoelectric vibrator is shown in Figures 13 and 14. It mainly consists of a cylindrical upper cover 8, a cylindrical lower cover 10, a circular elastic gasket 9, and a piezoelectric vibrator 14 with a circular bracket. It consists of four parts. The inner circular stepped through hole inside the lower cover is used to bond the three flat plates protruding from the outer edge of the circular support. Each piezoelectric vibrator is respectively fixed on each column of the circular support, and the vibration direction is along the direction of the circular support. radial.

The working principle of the cantilever piezoelectric vibrator valveless piezoelectric pump proposed by the present invention can be described as follows: when the piezoelectric ceramic sheet 12 and the metal sheet 13 are used as two poles, when a voltage is applied to the piezoelectric vibrator, if the direction of the voltage is the same as that of the piezoelectric ceramic If the polarization direction of the piezoelectric ceramic is the same, the piezoelectric ceramic will shrink. On the contrary, if the direction of the voltage is opposite to the polarization direction of the piezoelectric ceramic, the piezoelectric ceramic will expand. The expansion and contraction deformation of the piezoelectric ceramic will cause the expansion and deformation of the metal sheet bonded to it, but the expansion and contraction ability of the piezoelectric ceramic sheet and the metal sheet is different. When one end of the piezoelectric vibrator is fixed, it will make the piezoelectric vibrator The vibrator undergoes longitudinal bending deformation. Therefore, when the applied voltage is an alternating signal, the piezoelectric vibrator will form a periodic bending deformation vibration along the longitudinal direction, converting electrical energy into deformation mechanical energy, thereby driving the flow of fluid in the pump chamber. As shown in Figure 14, when any piezoelectric vibrator is vibrating longitudinally, on the one hand, it compresses the liquid near the upper surface of the vibrator along the vibration direction, and on the other hand, it quickly drives the liquid near the lower surface to move in a circular motion. , that is, the liquid near the upper and lower surfaces of the piezoelectric vibrator will be forced to make a circular motion with the piezoelectric vibrator. These liquids that are forced to move in a circle will escape in the radial direction of the circle due to the action of centrifugal force during the movement, and the escape speed will gradually increase outward along the center of the circle. Similarly, when the vibration direction of the piezoelectric vibrator is reversed, the liquid near the upper and lower surfaces of the piezoelectric vibrator will escape along the circumferential direction while moving in a circle with the piezoelectric vibrator. It can be seen that no matter whether the piezoelectric vibrator vibrates forward or reversely, the liquid near the upper and lower surfaces of the piezoelectric vibrator will perform centrifugal motion in the radial direction of the circumference. From a macroscopic point of view, it appears as a one-way flow of liquid.

Refer to Figures 3 to 17 for the specific implementation of the present invention, which mainly includes a cylindrical upper cover 8, a cylindrical lower cover 10, a circular elastic gasket 9, a cantilever piezoelectric vibrator 7 with a bracket, and a circular bracket as shown in Figure 16 , 17 and the double-sided piezoelectric vibrator as shown in Figure 12 with six parts. The upper and lower covers are respectively provided with through holes 11 as pump inlets and outlets, and the inner circular steps of the lower cover are used to bond the cantilever vibrator bracket and the outer edge plate of the ring bracket, and the piezoelectric vibrators of the latter are respectively fixed on the ring Each column of the bracket, and the vibration direction is along the radial direction of the torus. The annular elastic gasket 9 is placed between the cylindrical upper and lower covers to prevent pump leakage. The cylindrical upper cover, annular elastic gasket and cylindrical lower cover are used through the surrounding bolt holes 6. The six bolts are joined together.

This implementation uses 220V, 50Hz AC voltage, and other frequency voltages can also be used; use double-sided piezoelectric vibrators, and apply AC power to the two poles of the piezoelectric vibrator—the piezoelectric ceramic sheet 12 and the metal sheet 13, so that the piezoelectric vibrator The vibrator produces periodic longitudinal bending deformation, thereby driving the work of the piezoelectric pump.

In this implementation, the support of the cylindrical upper cover 8, the cylindrical lower cover 10, the cantilever vibrator 7 and the ring support are made of plexiglass. The piezoelectric vibrator is commercially available, with a length of 50mm, a width of 25mm and 15mm, the thickness of the piezoelectric ceramics and the metal sheet are both 0.1mm, the metal sheet is 13, and the material is brass. The annular elastic gasket 9 is made of elastic polymer material, such as rubber or silica gel.

Claims (2)

1. A valveless piezoelectric pump, comprising a pump body and a piezoelectric vibrator, is characterized in that it also includes an annular elastic gasket (9), and the pump body is composed of a cylindrical upper cover (8) and a cylindrical lower cover (10) are connected to each other; the piezoelectric vibrator is a cantilever piezoelectric vibrator (7) with a support, which is pasted on the inner circle step of the cylindrical lower cover (10), and the cantilever piezoelectric vibrator (7) with a support ) includes a bracket and a double-sided piezoelectric vibrator. The double-sided piezoelectric vibrator is fixed on the bracket to form a cantilever support structure. The double-sided piezoelectric vibrator is composed of a piezoelectric ceramic sheet (12) and a metal sheet (13). , two piezoelectric ceramic sheets (12) are pasted on the outer surfaces of both sides of the metal sheet (13) respectively; Between, through the bolt holes of the cylindrical upper cover (8), the bolt holes of the annular elastic gasket (9) and the bolt holes of the cylindrical lower cover (10), bolt the cylindrical upper cover (8), the annular elastic gasket The sheet (9) and the cylindrical lower cover (10) are connected together; the center of the cylindrical upper cover (8) has a pump inlet; the center of the cylindrical lower cover (10) has a pump outlet. 2. A valveless piezoelectric pump, comprising a pump body and a piezoelectric vibrator, is characterized in that it also includes an annular elastic gasket (9), and the pump body is composed of a cylindrical upper cover (8) and a cylindrical lower cover (10) are connected to each other; the piezoelectric vibrator is a piezoelectric vibrator (14) with a ring bracket, which is pasted on the inner circle step of the cylindrical lower cover (10), and the piezoelectric vibrator with a ring bracket (14) Including a ring bracket and 3 to 10 double-sided piezoelectric vibrators, 3 to 10 double-sided piezoelectric vibrators are evenly installed on the circumference of the ring bracket by using columns to form a three-dimensional cantilever support structure , each double-sided piezoelectric vibrator is composed of a piezoelectric ceramic (12) and a metal sheet (13), and two piezoelectric ceramic sheets (12) are respectively pasted on the outer surfaces of both sides of the metal sheet (13); the circle The ring elastic gasket (9) is placed between the cylindrical upper cover (8) and the cylindrical lower cover (10), through the bolt hole of the cylindrical upper cover (8), the bolt hole of the annular elastic gasket (9) and the cylinder shaped lower cover (10) bolt hole, with bolts cylindrical upper cover (8), ring elastic gasket (9) and cylindrical lower cover (10) are connected together; described cylindrical upper cover (8) A pump inlet is opened in the center; a pump outlet is opened in the center of the cylindrical lower cover (10).

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