Reverse jet piezoelectric pump

Abstract

The invention relates to a novel reverse jet piezoelectric pump for driving fluid, in particular to a high-flow reverse jet piezoelectric pump which is opposite to a jet pump in the prior art in fluid flow direction through an analogue simulation test of a piezoelectric jet pump and the like.

Description

Technical Field

[0001] A novel reverse jet piezoelectric pump for driving fluid is provided. Through simulation experiments on piezoelectric isojet pumps, a high-flow reverse jet piezoelectric pump with a fluid flow direction opposite to that of the prior art jet pump is obtained. Background Art

[0002] In the design of the piezoelectric jet pump, the piezoelectric micro blower designed in CN101542122A, that is, the piezoelectric driven gas jet pump is as follows Figure 4 (Original attachment of CN101542122A Figure 1 ), and the porous jet pump 202411094690.1 previously applied by the applicant is designed as follows Figure 3 As shown. The piezoelectric ceramic 1 of the piezoelectric actuator component drives the vibrator to bend and deform up and down under the drive of the alternating signal and drives the air, so that the fluid in the pump chamber is compressed or expanded, and a large positive pressure or negative pressure is generated in the pump chamber: during the positive pressure period, the fluid (such as air) in the pump chamber is ejected at high speed from a single or multiple small hole jet holes on the upper wall of the pump chamber to form a cylindrical high-speed fluid jet, which passes through the interlayer and then flows out through the corresponding small hole jet holes of the pump housing (such as Figure 4 During the negative pressure period, the fluid in the barrier (such as air) is sucked into the pump chamber (such as Figure 4 As shown in b in the figure), a non-return fluid jet pump without a check valve is obtained.

[0003] For the jet pump designed above, the applicant optimized the thickness of the pump's interlayer in the prior application 202411415732.7, and achieved a significant increase in the pump flow rate, with the pump flow rate reaching up to 1700ml / min. The simulation and experiment were consistent, and the technical effect was significant. Summary of the invention

[0004] In the above-mentioned prior art, the jet holes or openings (multiple small holes or can be combined into one large hole) of the pump casing corresponding to the jet holes of the pump chamber are all fluid outlets of the pump. In the half cycle when the volume of the pump chamber increases, the fluid flows into the barrier from the opening of the fluid barrier on the pump side and is further sucked into the pump chamber. In the half cycle when the volume of the pump chamber decreases, the fluid in the pump chamber is pressurized and flows out of the pump chamber at high speed, passes through the fluid barrier and the jet holes or openings of the pump casing, and flows out of the pump body. The flow process of the fluid in one cycle is: outside world - inlet of the barrier side wall - barrier - pump casing jet hole - pump chamber - pump chamber jet hole - through the barrier - pump casing jet hole and outlet - outside world. Among them, during the gas movement process at the pump casing outlet, the fluid flow is unidirectional and there is no backflow: pump chamber - pump casing jet hole - through the barrier - pump casing jet hole and outlet - one-way exhaust to the outside world.

[0005] A completely new design of a jet pump is proposed in this application, such as Figure 1 As shown, the structure and Figure 3 The prior art is similar to the prior art, but the technical effect of fluid flow is completely opposite to the prior art design and more complicated. The fluid flows in from the opening of the pump housing (i.e., the fluid outlet of the prior art) and flows out of the pump body from the side opening of the fluid barrier (i.e., the fluid inlet of the prior art). The fluid outlet and inlet of the pump are completely reversed from the prior art. Therefore, the jet pump of the present application can be called a reverse jet pump, while the prior art such as Figure 3 and 4 The jet pump can be called a forward jet pump or simply a jet pump.

[0006] refer to Figure 2 , is an instantaneous image of fluid motion obtained by computer simulation program, which is a continuous screenshot in time sequence every tenth of a cycle. Figure 2 .1 The pump chamber begins to compress and the pump chamber jet hole begins to discharge fluid upward. Figure 2 .5 Fluid discharge reaches the maximum, and at this time, there are two places discharging fluid at the same time: on the one hand, the inlet of the central pump shell is discharging fluid upward, and this part of the fluid comes from the pump chamber. On the other hand, the outlet on the side of the partition is also discharging fluid and reaches the maximum. This part of the discharged fluid comes from the outer part of the partition outside the jet hole of the pump chamber. Then the volume of the pump chamber begins to increase and enters the suction stage. The jet hole on the pump chamber begins to have a dark high-speed part that inlet air inward. In particular, unlike the jet pump of the prior art, in Figure 2 In .9 and 2.10, a large amount of fluid flows into the pump casing inlet, and most of it does not enter the pump chamber, but turns around and enters the outer part of the partition, forming the partition air intake (in Figure 2.10 is the part of the fluid movement with high speed flow marked with 11). The reason for this analysis is that the second diaphragm under the interlayer is very thin stainless steel with a thickness of only 0.1 mm. Under the instigation of the expansion and compression of the pump chamber, the second diaphragm also produces large deformation and displacement, and the thickness of the interlayer also changes periodically and lags behind the change of the pump chamber. At the end of the pump chamber suction, the outer part of the interlayer (the part outside the pump chamber jet hole) is in the stage of volume increase and in a negative pressure state, so the jet of the fluid sucked by the pump chamber jet hole instigates a large inflow flow, and most of the fluid flows to the outer part of the interlayer, forming an interlayer intake of reverse jet. Compared with the forward jet design of the two references mentioned above, it can be seen that the inlet and outlet processes are completely different: in the prior art design, the air intake path is mainly or entirely from: the inlet of the interlayer side wall - the outer part of the interlayer - the pump chamber jet hole - the pump chamber. The exhaust process is: pump chamber - pump chamber jet hole - the inner part of the interlayer - the outlet on the pump housing. In this design, there are two parallel processes for air intake, one is the pump chamber intake process, from the inlet on the pump housing - through the inner part of the barrier - the pump chamber jet hole - the pump chamber; the other is the intake process of the outer part of the barrier, from the inlet on the pump housing - the outer part of the barrier. In this design, there are also two parallel exhaust paths for exhaust, one is the same as the prior art, pump chamber - pump chamber jet hole - inlet on the pump housing. At the same time, there is a larger opposite fluid exhaust path: the outer part of the barrier - the outlet of the barrier side wall.

[0007] exist Figure 1 In the figure, when the radius of the center line of the pump cavity jet hole gradually increases from 0.75 mm to 1.35 mm, the pump flow rate remains positive and basically increases gradually. Positive flow rate means that the fluid flows out of the pump housing opening and flows into the inlet of the interlayer side wall. When the jet hole moves further outward, the radius of the center line increases from 1.35 to 1.6 mm, and the pump flow rate gradually decreases. In the example of 40 jet holes evenly distributed on the circle of the center line, when the jet holes are distributed on a circle with a radius of 1.5 mm, the pump flow rate is still about 2400 ml / min, and after the jet holes move outward to a circle with a radius of 1.6 mm, the flow rate is greatly reduced to 700 ml / min. Further increasing the center line means that the jet hole moves outward further, and the pump flow rate changes from positive to negative: when the radius of the center line is 1.7 mm, the flow rate is -1244 ml / min, and when the radius of the center line is increased to 1.9 mm, the flow rate is the largest, which is -3249 ml / min. As the jet hole moves further outward, the flow rate gradually decreases to -2000 and -1000 ml / min. The negative flow rate here means that the direction of the actual fluid in and out of the pump is completely opposite to the inlet and outlet set in the prior art. The opening on the pump housing changes from outlet to inlet, and the opening on the side wall of the interlayer changes from inlet to outlet.

[0008] The reasonable explanation for the above results is that the deformation of the second diaphragm is not uniform as a whole, but the central part and the outer part are opposite, that is, when the central part is deformed upward, the outer part of the second diaphragm is deformed downward, and they are in opposite phases. The dividing line between the two areas is roughly a circle with the center of the pump cavity as the center and a radius of 1.6 mm. Therefore, when the pump cavity jet holes are distributed on a circle with a radius of 750 to 1350 microns, the forward / exhaust jet of the pump cavity jet holes is synchronized with the movement of the central part of the second diaphragm and is strengthened, and a larger flow rate of the forward jet is obtained. When the jet holes are distributed on a circle with a radius of about 1900 microns, the reverse / inhalation jet of the jet holes is synchronized with the anti-phase movement of the outer part of the second diaphragm, and the reverse jet (inhalation jet) strengthens the reverse suction flow of the fluid in the outer part of the interlayer, thereby obtaining a larger suction flow of the reverse jet. At the same time, the volume change of the outer part of the partition is relatively large: the movement of the second diaphragm is instigated by the movement of the piezoelectric vibrator. Since the second diaphragm is very thin (0.1 mm metal, while the vibrator including piezoelectric ceramics and metal parts is 0.31 mm thick, and the stiffness of piezoelectric ceramics is much greater than that of metal), the second diaphragm is easy to deform, which will produce a larger amplitude than the amplitude of the piezoelectric vibrator, thereby producing a large volume change on the outer part of the partition, and then a large fluid inflow and outflow. When the design is reasonable, this fluid inflow and outflow is harmoniously resonant or time-synchronously coupled with the fluid inflow and outflow jets of the pump chamber, and the fluid inflow and outflow flow of the outer part of the partition is strengthened, which will produce a large partition flow rate (referring to the pump flow rate contributed by the inflow and outflow of the partition fluid. In contrast, the flow rate of the forward jet pump in the prior art mainly comes from the contribution of the fluid inflow and outflow of the pump chamber, which can be called the pump chamber flow rate). It should be pointed out that this boundary of the second diaphragm will change according to the size and design of the pump, and is not fixed. For similar Figure 1 The design of this boundary is roughly near the circle of the following radius on the second diaphragm: the radius is about 1 / 4 to 2 / 5 of the radius of the piezoelectric ceramic. Therefore, the radius of the center line of the jet hole can be taken as more than 1 / 4 of the radius of the piezoelectric ceramic, about 1 / 3 or larger. The appropriate size can be found by simulation for the specific design, and then the test verification can be found to find the optimal size of the center line radius of the jet hole to obtain the maximum flow of the reverse jet.

[0009] Compared with the jet pump design of the prior art, this design has a larger flow rate, and because the jet holes of this design are distributed on the second diaphragm with the center of the pump as the center and a larger radius (the jet holes in the prior art jet pump are distributed on a circle with a radius of 750 to 1350 microns or the center of the pump, while the jet holes of this design are distributed on a circle with a radius of 1700 to 2200 microns, about 1900 microns). Therefore, this design can use a larger number of small-hole jet holes, such as 48 or 64 small jet holes (with a radius of 125 microns or less). When the thickness of the interlayer is 5 times the radius of the jet hole, the thickness of the interlayer is thinner, thereby obtaining a thinner total thickness of the pump. Moreover, the structure of central air intake and side air outlet is also more convenient than the central air outlet and side air intake of the prior art in some applications.

[0010] The radius of the center line of the pump cavity jet hole of the present design is preferably between 1700 and 2200 microns; more preferably, the radius of the center line of the pump cavity jet hole is preferably between 1800 and 2000 microns; more preferably, the radius of the center line of the pump cavity jet hole is between 1850 and 1950 microns. If the radius of the piezoelectric ceramic is used as the scale, the radius of the center line of the pump cavity jet hole is preferably between 30% and 40% of the radius of the piezoelectric ceramic; more preferably, between 33% and 36% of the radius of the piezoelectric ceramic; more preferably, between 33.5% and 35.5% of the radius of the piezoelectric ceramic. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A cross-sectional view of the design of the present application is shown schematically.

[0012] Figure 2 The simulation results designed in this application are screenshots of the instantaneous velocity distribution every 1 / 10 cycle in one cycle of the fluid movement in the pump, with a total of 10 screenshots, marked as 2.1, 2.2,..., 2.10 respectively.

[0013] Figure 3 This is an illustration of the prior application for porous jet pump 202411094690.1.

[0014] Figure 4 It is the prior art CN101542122A schematic diagram, which is the original attachment of CN101542122A Figure 1 .

[0015] In the figure, 1 is the actuating component of the fluid pump made of piezoelectric ceramic or other actuating materials, 2 is the gasket of the piezoelectric actuating component, 3 is the diaphragm, 4 is the pump cavity, 5 is the second diaphragm, 6 is the air intake partition, 7 is a plurality of pump cavity jet holes, 8 is the fluid inlet on the pump housing 10, 9 is the pump housing, 10 is the opening of the partition side wall and the fluid outlet, and 11 is the larger partition air intake area that appears near the inlet of the pump housing during the air intake stage. The feeding electrode and the like are omitted in the figure. DETAILED DESCRIPTION

[0016] Combined with Figure 1 , giving the specific implementation method of this application, and further expounding the design concept of this application. According to the mechanism proposed in this application, it can be promoted and applied to various jet fluid pumps driven by electromagnetic actuation materials such as piezoelectric without creative labor. It only needs to imitate the analysis of pressure distribution and air intake in this application and reasonably design the distribution position of the jet holes. In various designs, including but not limited to the design of this application, and other actuation materials or mechanically driven fluid pumps, reverse jet jet fluid delivery can be realized to obtain a significant improvement in efficiency.

[0017] exist Figure 1In the pump, the electromagnetic actuator 1 is made of piezoelectric material or other materials, which bends and deforms up and down under the action of electrical and / or magnetic signals, driving the gasket 2 and the diaphragm 3 to bend and deform together, resulting in a significant change in the volume of the pump chamber 4, forming a large positive pressure or negative pressure. The jet holes of the pump chamber are arranged to be distributed on a circle, which is located outside the conversion boundary of the positive and negative displacement of the bending deformation of the second diaphragm, and is located in the low-pressure area in the pump chamber (when the central part of the pump chamber is at high pressure, the outer side of the pump chamber is also at high pressure, and the circular ring area of ​​a certain size between the center and the outer side of the pump chamber is at a relatively low pressure state). When the pump is working, in the intake stage, while the jet hole inhales air from the inlet of the pump housing into the pump chamber, a large amount of air flows into the outer part of the interlayer at the same time (the interlayer part located outside the jet hole of the pump chamber, and the interlayer part surrounded by the jet hole is called the central part of the interlayer). In the exhaust stage, while the jet hole ejects the exhaust gas upward and flows out of the air inlet 8, a large amount of gas is squeezed from the outer part of the interlayer and discharged from the outlet 10 of the side wall of the interlayer. At this time, the upward high-speed jet from the pump chamber jet hole enters the inlet 8, forming an effect of sealing the inner side of the outer part of the interlayer, similar to the effect of a "wind curtain". The exhaust of the outer part of the interlayer at this stage is more or can only be discharged from the outlet of the outer side wall of the interlayer. It can be seen that the design of this application has two fluid flow processes: one is the fluid flow process in the pump chamber, which is divided into the exhaust stage from the pump chamber through the jet hole 7, through the interlayer and the air inlet 8; and the intake stage from the inlet 8, through the interlayer and the pump chamber jet hole into the pump chamber. In both stages, the inlet and outlet of the pump chamber pass through the opening 8 of the pump shell, and the positive and negative cancel each other. One is the fluid flow process of the outer part of the interlayer, which is also divided into two stages of intake and exhaust: the fluid enters the outer part of the interlayer from the outside of the pump through the air inlet 8, and some fluid enters the interlayer from the opening of the interlayer side wall. And the exhaust stage of the outer part of the interlayer exhausts from the outlet 10 of the interlayer side wall to the outside. The two processes are combined, and the inlet 8 is both the air inlet and the exhaust port of the pump chamber fluid during the pump chamber exhaust stage. However, the air intake flow rate of the inlet is greater than the exhaust flow rate in each cycle, and there is a net air intake flow rate. The outlet 10 has an air intake and an air outflow during the pump chamber and the interlayer suction stage, but the flow rate out of the outlet 10 is larger during the interlayer exhaust stage, so there is a net outflow flow rate at the outlet. In contrast, in the prior art, the applicant's prior application and another cited document such as Figure 4In the jet pump, the jet hole of the pump casing, which serves as the outlet, has only outflow flow in each stage when working stably in a reasonable design, and no inflow flow, that is, there is no backflow at all. Even in the degraded design, the outflow flow of the jet hole on the pump casing is greater than the inflow backflow flow. In the present design, the inlet 8 of the pump casing has an inflow flow greater than the outflow flow in each cycle when working stably. More importantly, in the prior art designs, there is only a process of fluid flow in the pump chamber, and the partition only participates in this process, but the partition does not have its own independent fluid flow process. In the design of the present application, in addition to the flow of fluid in the pump chamber, the fluid on the outer part of the partition has an independent flow process. In the design of the present application, there is still a large reverse flow after the inlet and outlet flows are offset. The working principle of this design is different from that of the jet pump of the prior art. The net flow direction of the fluid is completely opposite, and one is that there is no backflow or low backflow at the outlet, and the design purpose is to reduce backflow. The other is that there is a large backflow at the inlet and outlet, and the backflow is utilized. Moreover, there is another essential difference between the present design and the jet pump of the prior art. In the prior art, such as Figure 3 and Figure 4 In the two designs, the net flow of the pump comes only from the contribution of the fluid in and out of the pump chamber, which is the pump chamber flow. In the design of the present application, the net flow of the pump comes from the fluid in and out of the outer part of the pump's interlayer, which is the interlayer flow, and the fluid in and out of the pump chamber is only auxiliary in this design, and the fluid in and out of the pump chamber flows through the inlet of the pump housing, the in and out cancel each other out, and there is no contribution to the pump flow. At the same time, the pump chamber air intake path of this design is different from that of the aforementioned jet pump. The pump chamber air intake of this design comes from the inlet on the pump housing (i.e., the outlet of the prior art), while in the prior art, the goal is to completely intake air from the interlayer and eliminate air intake from the pump housing opening.

[0018] Therefore, the present design is different from the forward jet pump of the prior art. The optimal value of the interlayer thickness is not 5 times the radius of the jet hole, but larger. When the interlayer thickness is 5 to 8 times or greater than 6 times the radius of the jet hole, the pump flow rate is larger. The pump flow rate is 3249 ml / min when the interlayer thickness is 5 times, i.e. 625 / 125 times, of the jet hole radius, to 3911 ml / min when it is 700 / 125 times, to 6531 ml / min when it is 800 / 125 times. It can be understood that as the thickness of the interlayer increases, the interlayer is easier to inlet, the air intake is large, and thus a larger flow rate is generated. Compared with the maximum flow rate of 3696 ml / min obtained after optimization of the forward jet pump of the prior art, the maximum flow rate of the reverse jet pump of the present application is increased to 1.77 times.

[0019] The technical core of this application is to overcome the negative teaching of no backflow of the forward jet in the prior art through simulation analysis based on fluid mechanics analysis and inspiration in the jet fluid pump driven by electromagnetic actuation materials such as piezoelectric materials, and reasonably arrange the position of the jet hole to obtain synchronization or co-coupling of the pump cavity jet and the fluid flow of the outer part of the interlayer, drive the large flow fluid movement of the outer part of the interlayer, thereby obtaining a reverse jet of the fluid opposite to the prior art design, and obtain a new reverse jet jet pump design, and the flow rate is significantly increased, and significant technical progress and technical benefits are obtained. This design can be used in the design of other jet pumps without the need for creative labor or overcoming any prejudice. For example, any actuating material driven pump, including mechanically driven pumps, as long as the pump chamber is repeatedly compressed and expanded, multiple jet holes 7 can be set on the wall of the pump chamber, i.e., on a circle of a certain size on the second diaphragm, and a corresponding outer shell and a large opening or inlet 8 on the outer shell that is concentric with the center line of the jet hole 7 are set after a fluid partition of a certain height or distance, so that the compressed fluid in the pump chamber can be jetted at high speed and flow through the jet hole 7, the partition and the opening 8 to the outside. When inhaling, the fluid is absorbed from the inlet 8 to replenish the pump chamber. At the same time, a second fluid movement is generated: when the pump chamber is inhaling, a large flow of fluid flows from the outside through the inlet 8 into the outer part of the partition, and in the second half of the cycle, the volume of the outer part of the partition decreases, and the fluid is squeezed out of the outlet 10 of the side wall of the partition. In the case of a piezoelectric pump, the piezoelectric material can be a single layer or multiple layers, and there can be more than one piezoelectric vibrator, such as Figure 1 The second diaphragm in the device can be replaced by a piezoelectric vibrator, that is, a combination of a diaphragm and a piezoelectric material. Various prior art common jet pump designs, or future jet pump technologies, can be simply introduced into the design of the present application without the need for creative labor.

[0020] The improved design of this application is supported by simulation and experimental verification, and has achieved significant technological progress and significant technological benefits. The core performance pump flow rate of the pump has been greatly improved from 1700ml / min in the prior art to 6531ml / min, and a new jet pump design has been obtained.

Claims

1. A piezoelectric reverse jet pump, comprising a vibrator made of piezoelectric material and metal material, a second diaphragm, the second diaphragm and the vibrator are spaced at a certain height to form a closed pump cavity, a pump shell is arranged at a certain height on the second diaphragm, a fluid barrier is formed between the pump shell and the second diaphragm, a plurality of pump cavity jet holes are distributed on a circle of a certain size on the second diaphragm to connect the pump cavity and the barrier, a fluid inlet is provided on the pump shell, the fluid inlet surrounds the pump cavity jet hole, and a fluid outlet is provided on the side wall of the barrier, characterized in that: In one cycle, the air intake flow rate at the fluid inlet of the pump casing is greater than the air outlet flow rate, and in one cycle, the air outlet flow rate at the fluid outlet of the partition side wall is greater than the air intake flow rate. During the air intake stage of the pump casing inlet, the fluid flowing into the pump casing inlet flows into the outer part of the partition at the same time as flowing into the pump cavity.

2. The piezoelectric reverse jet pump according to claim 1, further characterized in that: The pump cavity jet holes are distributed on a circle of the second diaphragm with the center of the pump cavity as the center and a radius of 1700 to 2200 microns.

3. The piezoelectric reverse jet pump according to claim 1, further characterized in that: The pump cavity jet holes are distributed on a circle of the second diaphragm with the center of the pump cavity as the center and a radius of 1800 to 2000 microns.

4. The piezoelectric reverse jet pump according to claim 1, further characterized in that: The pump cavity jet holes are distributed on a circle of the second diaphragm with the center of the pump cavity as the center and a radius of 1850 to 1950 microns.

5. The piezoelectric reverse jet pump according to claim 1, further characterized in that: The pump cavity jet holes are distributed on a circle of the second diaphragm with the center of the pump cavity as the center and a radius that is 30% to 40% of the radius of the piezoelectric material.

6. The piezoelectric reverse jet pump according to claim 1, further characterized in that: The pump cavity jet holes are distributed on a circle of the second diaphragm with the center of the pump cavity as the center and a radius of 33% to 36% of the radius of the piezoelectric material.

7. The piezoelectric reverse jet pump according to claim 1, further characterized in that: The pump cavity jet holes are distributed on a circle of the second diaphragm with the center of the pump cavity as the center and a radius that is 33.5% to 35.5% of the radius of the piezoelectric material.

8. The piezoelectric reverse jet pump according to claim 1, further characterized in that: The ratio of the thickness of the interlayer to the radius of the pump cavity jet hole is greater than or equal to 6.

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