Miniature diaphragm pump with columnar bubble and liquid monitoring function

Abstract

In order to improve the stability and reliability of the micro diaphragm pump, the invention provides the micro diaphragm pump with the columnar bubble and liquid monitoring function. The channel is formed in the pump cavity, the valve body is installed in the channel, the valve body is composed of the upper layer, the middle layer and the friction layer, the sensing part is arranged on the middle layer, the sensing area is formed through cooperation of the friction layer and the sensing part, and then columnar bubbles and liquid in the micro diaphragm pump are monitored. The device is small in size, high in energy density, high in controllability and capable of monitoring columnar bubbles and liquid.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of diaphragm pump, and particularly relates to a micro diaphragm pump with columnar bubble and liquid monitoring functions. BACKGROUND

[0002] Diaphragm pump is to realize the volume change of cavity by diaphragm vibration, and to realize the one-way delivery of fluid by combining with the one-way valve structure. The diaphragm separates the moving parts and the delivered fluid, which can well avoid the problem of fluid leakage, and since the diaphragm pump realizes the fluid pumping by the volume change of the cavity, it has good self-suction capacity and flow regulation effect. The diaphragm pump has been widely applied in the fields of chemical industry, medical treatment and the like. For example, Chinese patent CN201180073680.4 discloses a micro diaphragm pump with a diaphragm chamber connected with one side of a suction valve and a discharge valve. The diaphragm pump has small size, good productivity and high flow control precision. When the diaphragm pump delivers single-phase fluid, it often appears to be mixed with phase fluid, which will affect the stable fluid delivery (such as the purity of infusion, the metering accuracy and the like), and therefore, the monitoring of columnar bubbles or liquid drops can effectively solve this working condition. For example, in the application of infusion in the medical field, the columnar bubbles are monitored to prevent the gas from entering and to ensure the purity of infusion; when the liquid flow is precisely delivered, the volume of the bubbles mixed in the liquid is identified to compensate the metering accuracy and to ensure the liquid delivery amount; and meanwhile, the two-phase flow condition is detected to realize fault alarm. SUMMARY

[0003] In order to realize the columnar bubble and liquid monitoring of the micro diaphragm pump, the present application has the following structure, including a vibrating diaphragm, a base, a pump cavity, a valve body, an inlet and an outlet.

[0004] Further, the inlet and the outlet can be provided with joints for connecting the external fluid pipeline; the inlet enters the working fluid, and the outlet discharges the working fluid.

[0005] Further, the inlet is communicated with the valve body through a second flow channel; the outlet is communicated with the valve body through a first flow channel; the valve body controls the communication and disconnection of the first flow channel with the cavity; and the valve body controls the communication and disconnection of the second flow channel with the cavity.

[0006] Further, the outer periphery of the vibrating diaphragm is connected with the base; the vibrating diaphragm is driven by an external driving part to generate reciprocating bending vibration; and the vibration of the vibrating diaphragm directly acts on the pump cavity to cause the volume change of the pump cavity, and in the process of the alternating volume change of the pump cavity, the one-way driving of fluid can be realized by combining with the valve body (with the one-way valve effect).

[0007] Further, the lower part of the diaphragm is connected with a piezoelectric wafer concentrically, the piezoelectric wafer drives the diaphragm to reciprocating bending vibration as an external driving component; the polarization direction of the piezoelectric wafer is vertical direction, the upper and lower surfaces of the piezoelectric wafer are provided with silver electrode layers, and the specific process of the piezoelectric wafer driving the diaphragm to reciprocating vibration is that the piezoelectric wafer applies an alternating voltage signal to the electrode surface, and under the action of the inverse piezoelectric effect, the piezoelectric wafer drives the diaphragm to bending vibration.

[0008] Further, the piezoelectric wafer is circular and flat, for example, composed of lead zirconate titanate (PZT) ceramic; the outer diameter of the piezoelectric wafer is smaller than the outer diameter of the diaphragm.

[0009] Further, the diaphragm is connected with an insulating film on the side facing the pump cavity, and the insulating film is used to isolate the diaphragm from the electrical conduction of the fluid in the pump cavity.

[0010] Further, the insulating film is circular and flat, for example, composed of resin; the outer diameter of the insulating film is the same as the outer diameter of the diaphragm.

[0011] Further, a channel is provided at the center of the pump cavity; the channel is in communication with the pump cavity; the valve body is installed in the channel.

[0012] Further, the height H1 of the channel after installing the valve body is not less than the height H2 of the pump cavity.

[0013] Further, the main section of the channel is a circle, that is, the middle is rectangular and the two sides are semicircular.

[0014] Further, the valve body includes an inlet valve, an outlet valve, and a sensing area.

[0015] Further, the sensing area is located between the inlet valve and the outlet valve; the sensing area covers the area that the fluid must pass through from the inlet valve to the outlet valve; the inlet valve and the outlet valve are located on both sides of the channel, and the sensing area is located in the middle area of the channel.

[0016] Further, the sensing area includes a sensing part and a friction layer; the sensing part is connected with the base; the friction layer is connected with the sensing part, the friction layer covers the sensing part to ensure that the sensing part does not contact the working fluid in the pump cavity; the friction layer directly contacts the working fluid in the pump cavity.

[0017] Further, the sensing part is provided with a connecting part, which extends to the outside of the diaphragm pump and is in communication with the external sensing lead.

[0018] Further, the sensing part is square and flat, for example, composed of copper.

[0019] Further, the friction layer is flat plate, for example, composed of polytetrafluoroethylene (PTFE) material, which is matched with the sensing part to form the friction electrostatic generation module, which can be used for sensing the columnar bubble or liquid.

[0020] Further, the pump cavity surface is provided with a film; the film is consistent with the hydrophilic or hydrophobic wetting of the friction layer, which can make the pump cavity and the channel surface keep consistent with the hydrophilic or hydrophobic wetting, which can make the columnar bubble or liquid not enter or stay in the pump cavity, on the other hand, which can also reduce the signal influence of the pump cavity surface on the sensing part; in the embodiment, the film is composed of the same material as the friction layer, that is, composed of polytetrafluoroethylene (PTFE) material.

[0021] Further, the inlet valve realizes the one-way flow of fluid from top to bottom, that is, the one-way valve controls the one-way flow of the second flow channel to the pump cavity; the outlet valve realizes the one-way flow of fluid from bottom to top, that is, the one-way valve controls the one-way flow of the pump cavity to the first flow channel.

[0022] Further, the inlet valve and the outlet valve are both wheel type one-way valve structures, which include cantilever beam, valve plate and valve seat; the cantilever beam connects the valve seat and the valve plate, and is circumferentially symmetrically distributed with the center of the valve plate as the center, and is used for supporting the valve plate; the valve seat is provided with a valve hole; the valve seat is connected with the base; the valve hole is coaxially installed with the valve plate.

[0023] Preferably, another preferred embodiment of the channel, the channel is an elliptical column; the long axis line 2a direction of the elliptical cross section of the channel is horizontal direction; the long half axis length a of the channel is not less than 1.5 times of the short half axis length b; the long half axis length a of the channel is not greater than 1 / 2 of the inner diameter of the pump cavity.

[0024] Preferably, another preferred embodiment of the valve body, the valve body is sequentially connected with upper layer, intermediate layer and friction layer from top to bottom, the connection mode of the upper layer, intermediate layer and friction layer is stacking, and the outer periphery profiles of the upper layer, intermediate layer and friction layer are the same.

[0025] Further, the upper layer is flat plate, for example, composed of resin; the upper layer is provided with first through hole and second through hole, the inner diameter of the first through hole is D11, and the inner diameter of the second through hole is D21; the intermediate layer is flat plate; the intermediate layer includes support part and mounting area; the mounting area is hollow area, which is used for mounting the sensing part; the support part is flat plate, for example, composed of resin; the support part is provided with first valve part and second valve part.

[0026] Further, the first valve part and the second valve part are central axis symmetric.

[0027] Further, the installation area is inlaid with a sensing part, which is seamlessly connected with the installation area in the embodiment.

[0028] Further, the sensing part has the same thickness as the intermediate layer, and is seamlessly connected with the support part; the sensing part is located between the first valve part and the second valve part.

[0029] Further, the sensing part is provided with a connecting part, which extends outside the diaphragm pump and is in communication with an external sensing lead.

[0030] Further, the friction layer is flat, for example, is made of polytetrafluoroethylene (PTFE) material, and is matched with the sensing part to form a friction electrostatic generation module (i.e., forms a sensing area), which can be used for sensing columnar bubbles or liquid; the friction layer is provided with a third through hole and a fourth through hole, the inner diameter of the third through hole is D14, and the inner diameter of the fourth through hole is D24.

[0031] Further, the first valve part and the second valve part both adopt a wheel type one-way valve structure, which includes a cantilever beam and a valve plate; the cantilever beam connects the support part and the valve plate, and is circumferentially symmetrically distributed with the valve plate as the center, and is used for supporting the valve plate; the outer diameter of the valve plate in the first valve part is D13, and the outer diameter of the valve plate in the second valve part is D23; the inner diameter of the first valve part is D12, and the inner diameter of the second valve part is D22; in the embodiment, the first valve part and the second valve part are symmetrically mirror image structures.

[0032] Further, the first through hole, the first valve part and the third through hole are coaxially installed to form an outlet valve; the second through hole, the second valve part and the fourth through hole are coaxially installed to form an inlet valve.

[0033] Further, the first through hole, the first valve part and the third through hole are combined to form a one-way valve (i.e., an outlet valve), which realizes one-way flow of fluid in a downward-to-upward direction, i.e., controls one-way flow of the pump cavity to the first flow channel; in the embodiment, the inner diameter D11 of the first through hole is equal to the inner diameter D12 of the first valve part; the outer diameter D13 of the valve plate in the first valve part is greater than the inner diameter D14 of the third through hole, and 1.1 D14<D13<1.3 D14.

[0034] Further, the second through hole, the second valve part and the fourth through hole are matched to form a one-way valve (i.e., an inlet valve), which realizes one-way flow of fluid in an upward-to-downward direction, i.e., controls one-way flow of the second flow channel to the pump cavity; in the embodiment, the inner diameter D24 of the fourth through hole is equal to the inner diameter D22 of the second valve part; the outer diameter D23 of the valve plate in the second valve part is greater than the inner diameter D21 of the second through hole, and 1.1 D21 < D23 < 1.3 D21.

[0035] Preferably, a preferred embodiment of the valve body is shown, a protrusion is arranged at the third through hole, for example, made by hot pressing process, the protrusion lifts up the corresponding valve piece, which can realize the pre-tightening of the valve piece, realize better sealing of the pump cavity, and make the valve piece outflow closer to the upper layer, so that the columnar liquid or gas is not easy to stay at the valve piece; a protrusion is arranged at the second through hole, for example, made by hot pressing process, the protrusion lifts up the corresponding valve piece, which can realize the pre-tightening of the valve piece, realize better sealing of the pump cavity, and make the corresponding valve piece outflow closer to the friction layer, so that the columnar liquid or gas is more easily entered into the sensing area of the sensing part and is not easy to stay at the valve piece.

[0036] The working principle of the diaphragm pump is as follows: under the driving of an alternating voltage signal, the piezoelectric wafer drives the diaphragm to periodically bend and vibrate, under the bending vibration of the diaphragm, the volume of the cavity will alternately increase and decrease, combined with the one-way valve function of the valve body, the working fluid will flow from the inlet to the outlet in one direction. Specifically, when the pump cavity volume increases, the pump cavity pressure decreases, under the action of pressure difference, the outlet valve closes and the inlet valve opens, the fluid enters the pump cavity from the second flow channel; when the pump cavity volume decreases, the pump cavity pressure increases, under the action of pressure difference, the outlet valve opens and the inlet valve closes, the fluid flows from the pump cavity into the first flow channel, after the volume of the pump cavity driven by the diaphragm alternately changes periodically, the working fluid will form a stable one-way flow, realizing the pumping effect of the fluid.

[0037] A channel is arranged in the center of the pump cavity, the channel is located in the center, in the case of equal total volume of the pump cavity (including the channel), the arrangement of the channel can reduce the dead volume (the volume of the area that cannot be covered by the vibration of the diaphragm) of the periphery of the pump cavity, which can improve the working performance of the diaphragm pump; at the same time, according to the flat plate flow theory (for the sake of simplifying the analysis, the fluid passing through the pump cavity is regarded as flat plate flow), due to the arrangement of the channel increasing the distance between the flat plates, the arrangement of the channel can reduce the pressure drop of the fluid flowing in the pump cavity, which will reduce the energy loss of the fluid, and further improve the energy conversion efficiency and working performance of the diaphragm pump.

[0038] At the same time, since the valve body is arranged in the channel, the design of the channel can make the pump cavity obtain the effect of converging flow, that is, the fluid mainly passes through the channel, because the arrangement of the channel makes the height of the cavity around the pump cavity very small, the height of the cavity around the pump cavity in the present application is 0.1mm, which makes it difficult for the working fluid to enter the periphery of the pump cavity, and the fluid mainly flows in the channel during the fluid pumping process, which will bring many benefits, one is to reduce the retention of other impurities in the pump cavity, and two is that the columnar bubbles or droplets to be detected will flow in the channel from the inlet to the outlet, which is crucial for the valve body to monitor the columnar bubbles or liquid.

[0039] When the columnar bubble enters, before reaching the sensing part area, the bubble moves along the friction layer, the friction layer and the working fluid (liquid) are in full contact, the friction layer and the working fluid (liquid) are respectively charged with equal negative and positive charges; when the columnar bubble begins to enter the sensing part area, the originally positively charged liquid in the sensing part area is removed, based on the triboelectric theory, the electrons of the valve body are transferred from the sensing part to the external sensing lead wire, forming an electric signal; when the columnar bubble completely moves in the sensing part area, the charge amount does not change; when the columnar bubble begins to leave the sensing part area, the originally positively charged fluid in the sensing part area is covered again, based on the triboelectric theory, the electrons of the valve body are transferred from the external sensing lead wire to the sensing part, forming an electric signal; by monitoring the static voltage of the sensing part, by calculating the time of voltage rise (the bubble begins to enter the sensing area, the voltage will gradually rise) or calculating the time of voltage drop (the bubble begins to leave the sensing area, the voltage will gradually drop) and the instantaneous fluid flow rate, the size of the bubble can be monitored, and at the same time, according to the time interval between the voltage rise point and the voltage drop point, the fluid flow in the pump cavity and whether there is impurity retention can be evaluated. At the same time, when the working fluid is a gas, when the columnar liquid enters, based on the triboelectric theory, the size of the columnar liquid can be monitored by calculating the voltage rise and voltage drop time.

[0040] The characteristics and advantages of the present application are: 1. Through the integrated valve body structure combined with the channel design, the stability of the diaphragm pump is high, the structure is simple, and the retention of impurities can be well avoided; 2. Through the integrated design of the friction layer and the copper electrode, the size of the columnar bubble or liquid can be sensed, and the reliability and integration of the pumping system can be greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a structure sectional view schematic diagram of a preferred embodiment of the present application; Figure 2 is an A-A sectional view schematic diagram of Figure 1 ; is a sectional view schematic diagram of Figure 3 is a partial enlarged view of the D area in Figure 1 ; is a sectional view schematic diagram of Figure 4 is a preferred embodiment of Figure 2 ; is a sectional view schematic diagram of a preferred embodiment of the present application; Figure 5 is a sectional view schematic diagram of a preferred embodiment of the present application; Figure 6 is a sectional view schematic diagram of Figure 5 ; is a sectional view schematic diagram of Figure 7 is a sectional view schematic diagram of a preferred embodiment of the present application; Figure 5 is a sectional view schematic diagram of a preferred embodiment of the present application; Figure 8 Figure 7 ​a bottom view (B view) of the valve body (4); Figure 9 is Figure 5 is a cross-sectional view of the valve body (4) in the middle layer (42) without the sensor part (6); Figure 10 is a cross-sectional view of the upper layer (41); Figure 11 (a) is a cross-sectional view of the middle layer (42) without the sensor part (6), Figure 11 (b) is a cross-sectional view of the middle layer (42) with the sensor part (6); Figure 12 is a cross-sectional view of the lower layer (43); Figure 13 is a preferred embodiment of the valve body (4); Figure 14 , Figure 15 , Figure 16 , Figure 17 is a schematic diagram of the sensing area (403) sensing the columnar bubble in the liquid environment; Wherein: 1 - base; 11 - first flow channel; 110 - outlet; 12 - second flow channel; 120 - inlet; 2 - diaphragm; 21 - piezoelectric wafer; 22 - insulating film; 3 - pump cavity; 31 - channel; 4 - valve body; 401 - inlet valve; 402 - outlet valve; 403 - sensing area; 41 - upper layer; 42 - middle layer; 43 - friction layer; 411 - first through hole; 412 - second through hole; 420 - support part; 421 - first valve part; 422 - second valve part; 423 - mounting area; 51 - valve plate; 52 - cantilever beam; 53 - valve seat; 530 - valve hole; 431 - third through hole; 432 - fourth through hole; 6 - sensor part; 61 - connecting part; 7 - membrane. DETAILED DESCRIPTION

[0042] The technical solutions of the present application will be described below in conjunction with the drawings. It should be noted that the terms "middle", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only used for the purpose of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0043] In the description of the present application, it is necessary to point out that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "linking" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0044] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0045] The technical solutions of the present application will be described clearly and completely below in combination with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments.

[0046] Please refer to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 、 Figure 11 、 Figure 12 、 Figure 13 、 Figure 14 、 Figure 15 、 Figure 16 、 Figure 17 The present application provides a micro diaphragm pump with columnar bubble and liquid monitoring function, as shown in Figure 1 , the present application includes a vibrating diaphragm 2, a base 1, a pump cavity 3, a valve body 4, an inlet 120, an outlet 110.

[0047] Further, the inlet 120 and the outlet 110 can be installed with joints for connecting the external fluid pipeline; the inlet 120 enters the working fluid, and the outlet 110 discharges the working fluid.

[0048] Further, the inlet 120 is communicated with the valve body 4 through the second flow channel 12; the outlet 110 is communicated with the valve body 4 through the first flow channel 11; the valve body 4 controls the communication and disconnection of the first flow channel 11 and the cavity 3; the valve body 4 controls the communication and disconnection of the second flow channel 12 and the cavity 3.

[0049] Further, the outer periphery of the vibrating diaphragm 2 is connected with the base 1; the vibrating diaphragm 2 is driven by an external driving component to produce reciprocating bending vibration; the vibration of the vibrating diaphragm 2 directly acts on the pump cavity 3, thereby causing the volume of the pump cavity 3 to change; during the alternating volume change of the pump cavity 3, the one-way driving of the fluid can be realized by combining the valve body 4 (with the effect of a one-way valve).

[0050] Further, the lower part of the vibrating diaphragm 2 is concentrically connected with a piezoelectric wafer 21, which drives the vibrating diaphragm 2 to reciprocating bending vibration as an external driving component; the polarization direction of the piezoelectric wafer 21 is vertical, and silver electrode layers are arranged on the upper and lower surfaces of the piezoelectric wafer 21; the specific process of the piezoelectric wafer 21 driving the vibrating diaphragm 2 to reciprocating vibration is that the piezoelectric wafer 21 applies an alternating voltage signal to the electrode surface, and under the action of the inverse piezoelectric effect, the piezoelectric wafer 21 drives the vibrating diaphragm 2 to bend and vibrate.

[0051] Further, the piezoelectric wafer 21 is in the shape of a circular flat plate, for example, composed of lead zirconate titanate (PZT) ceramic; the outer diameter of the piezoelectric wafer 21 is smaller than the outer diameter of the vibrating diaphragm 3.

[0052] Further, the vibrating diaphragm 2 is connected with an insulating film 23 on the side facing the pump cavity 3, which is used to insulate the vibrating diaphragm 2 from the electrical conduction of the fluid in the pump cavity 3.

[0053] Further, the insulating film 23 is in the shape of a circular flat plate, for example, composed of resin; the outer diameter of the insulating film 23 is the same as the outer diameter of the vibrating diaphragm 2.

[0054] Further, the pump cavity 3 is provided with a channel 31 in the center; the channel 31 is in communication with the pump cavity 3; the valve body 4 is installed in the channel 31.

[0055] Further, the height H1 of the channel 31 after installing the valve body 4 is not less than the height H2 of the pump cavity 3.

[0056] Further, as shown in Figure 2 , the main section of the channel 31 is in the shape of a circle, that is, the middle part is rectangular and the two sides are semicircular.

[0057] Further, as shown in Figure 1 and Figure 3 , the valve body 4 includes an inlet valve 401, an outlet valve 402, and a sensing area 403.

[0058] Further, as shown in Figure 3As shown, the sensing area 403 is located between the inlet valve 401 and the outlet valve 402; the sensing area 403 covers the fluid flow path between the inlet valve 401 and the outlet valve 402; in this embodiment, the inlet valve 401 and the outlet valve 402 are located on both sides of the channel 31, and the sensing area 403 is located in the middle area of the channel 31.

[0059] Further, the sensing area 403 includes a sensing part 6 and a friction layer 43; the sensing part 6 is connected to the base 1; the friction layer 43 is connected to the sensing part 6, and the friction layer 43 covers the sensing part 6 to ensure that the sensing part 6 does not contact the working fluid in the pump cavity 3.

[0060] Further, the sensing part 6 is provided with a connecting part 61 that extends outside the diaphragm pump and is in communication with an external sensing lead.

[0061] Further, the sensing part 6 is a square flat plate, for example, composed of copper.

[0062] Further, the friction layer 43 is a flat plate, for example, composed of polytetrafluoroethylene (PTFE) material, which is matched with the sensing part 6 to form a friction electrostatic generation module, which can be used for sensing columnar bubbles or liquid.

[0063] Further, the pump cavity 3 is provided with a film 7; the film 7 has the same hydrophilic and hydrophobic wettability as the friction layer 43, which can make the surface of the pump cavity 3 and the channel 4 have the same hydrophilic and hydrophobic wettability, which can prevent columnar bubbles or liquid from entering or staying in the pump cavity 3, and on the other hand, it can also reduce the signal influence of the surface of the pump cavity 3 on the sensing part 6; in this embodiment, the film 7 is composed of the same material as the friction layer 43, i.e., polytetrafluoroethylene (PTFE) material.

[0064] Further, the inlet valve 401 realizes one-way flow of fluid from top to bottom, i.e., the one-way valve controls the one-way flow of the second flow channel 12 to the pump cavity 3; the outlet valve 402 realizes one-way flow of fluid from bottom to top, i.e., the one-way valve controls the one-way flow of the pump cavity 3 to the first flow channel 11.

[0065] Further, the inlet valve 401 and the outlet valve 402 both adopt a wheel type one-way valve structure, which includes a cantilever beam 52, a valve plate 51, and a valve seat 53; the cantilever beam 52 connects the valve seat 53 and the valve plate 51, and the cantilever beam 52 is distributed in a circumferential symmetry around the center of the valve plate 51 and is used to support the valve plate 51; the valve seat 53 is provided with a valve hole 53; the valve seat 53 is connected to the base 1; the valve hole 53 is coaxially installed with the valve plate 51.

[0066] Preferably, as shown in FIG. 6, the valve plate 51 is provided with a plurality of valve holes 51, and the valve holes 51 are arranged in a circumferential symmetry around the center of the valve plate 51. Figure 4 and Figure 8The diagram shows another preferred embodiment of the channel 31, which is an elliptical column. The major axis 2a of the elliptical cross-section of the channel 31 is horizontal. The length a of the major semi-axis of the channel 31 is not less than 1.5 times the length b of the minor semi-axis. The length a of the major semi-axis of the channel 31 is not greater than 1 / 2 of the outer diameter of the pump chamber 3. In this embodiment, the diameter of the pump chamber 3 is 34 mm, the height H2 of the pump chamber 3 is 0.1 mm, the length of the major semi-axis of the channel 31 is 12 mm, the length b of the minor semi-axis of the channel 31 is 7.2 mm, and the height H1 of the channel 31 after the valve body 4 is installed is 0.1 mm.

[0067] Preferred, such as Figure 6 and Figure 9 The diagram shows another preferred embodiment of the valve body 4, which is connected from top to bottom with an upper layer 41, an intermediate layer 42 and a friction layer 43. The upper layer 41, the intermediate layer 42 and the friction layer 43 are connected in a stacked manner, and the outer periphery contours of the upper layer 41, the intermediate layer 42 and the friction layer 43 are the same.

[0068] Furthermore, such as Figure 10 As shown, the upper layer 41 is flat, for example, made of resin; the upper layer 41 is provided with a first through hole 411 and a second through hole 412, the inner diameter of the first through hole 411 is D11, and the inner diameter of the second through hole 412 is D21; as shown Figure 11 As shown in (a) and (b), the intermediate layer 42 is flat; the intermediate layer 42 includes a support portion 420 and a mounting area 423; the mounting area 423 is a hollow area used to mount the sensing portion 6; the support portion 420 is flat, for example, made of resin; the support portion 420 is provided with a first valve portion 421 and a second valve portion 422.

[0069] Furthermore, the first valve section 421 and the second valve section 422 are symmetrical about the central axis.

[0070] Furthermore, the mounting area 423 is inlaid with a sensing unit 6. In this embodiment, the sensing unit 6 is seamlessly connected to the mounting area 423.

[0071] Furthermore, the thickness of the sensing part 423 is equal to that of the intermediate layer 42, and its outer periphery is seamlessly connected to the support part 420; the sensing part 6 is located between the first valve part 421 and the second valve part 422.

[0072] Furthermore, such as Figure 11 As shown in (b), the sensing part 6 is provided with a connecting part 61, which extends outside the diaphragm pump and is connected to the external sensing wire.

[0073] Furthermore, such as Figure 12As shown, the friction layer 43 is flat plate, for example, composed of polytetrafluoroethylene (PTFE) material, which is matched with the sensing part 6 to form a friction electrostatic generation module (i.e. to form the sensing area 403), which can be used for sensing columnar bubbles or liquid; the friction layer 43 is provided with a third through hole 431 and a fourth through hole 432, the inner diameter of the third through hole 431 is D14, and the inner diameter of the fourth through hole 432 is D24.

[0074] Further, as shown in Figure 11 , the first valve part 421 and the second valve part 422 both adopt a wheel type one-way valve structure, which includes a cantilever beam 52 and a valve plate 51; the cantilever beam 52 is connected to the support part 420 and the valve plate 51, and is circumferentially symmetrically distributed with the valve plate 51 as the center, and is used for supporting the valve plate 51; the outer diameter of the valve plate 51 in the first valve part 421 is D13, and the outer diameter of the valve plate 51 in the second valve part 422 is D23; the inner diameter of the first valve part 421 is D12, and the inner diameter of the second valve part 422 is D22; in this embodiment, the first valve part 421 and the second valve part 422 are symmetrically mirror image structures.

[0075] Further, as shown in Figure 9 , the first through hole 411, the first valve part 421, and the third through hole 431 are coaxially installed to form the outlet valve 402; the second through hole 412, the second valve part 422, and the fourth through hole 432 are coaxially installed to form the inlet valve 401.

[0076] Further, as shown in Figure 9 , Figure 10 , Figure 11 , Figure 12 , the first through hole 411, the first valve part 421, and the third through hole 431 are combined to form a one-way valve (i.e. the outlet valve 402), which realizes one-way flow of fluid in the direction from bottom to top, i.e. controls one-way flow of the pump cavity 3 to the first flow channel 11; in this embodiment, the inner diameter D11 of the first through hole 411 is equal to the inner diameter D12 of the first valve part 421; the outer diameter D13 of the valve plate 51 in the first valve part 421 is greater than the inner diameter D14 of the third through hole 431, and 1.1 D14<D13<1.3 D14.

[0077] Further, as shown in Figure 9 , Figure 10 , Figure 11 , Figure 12As shown, the second through hole 412, the second valve part 422, and the fourth through hole 432 are matched to form a one-way valve (i.e. the inlet valve 401), which realizes one-way flow of fluid in the direction from top to bottom, i.e. controls one-way flow of the second flow channel 12 to the pump cavity 3; in the embodiment, the inner diameter D24 of the fourth through hole 432 is equal to the inner diameter D22 of the second valve part 422; the outer diameter D23 of the valve plate 51 in the second valve part 422 is greater than the inner diameter D21 of the second through hole 412, and 1.1 D21 < D23 < 1.3 D21.

[0078] Preferably, as Figure 13 As shown, a more preferred embodiment of the valve body 4 is shown, the third through hole 431 is provided with a protrusion 44, for example, made by hot pressing process, the protrusion 44 lifts the corresponding valve plate 51, which can realize pre-tightening of the valve plate 51, realize better sealing of the pump cavity 3, and make the outflow of the valve plate 51 closer to the upper layer 41, so that the columnar liquid or gas is not easy to stay at the valve plate 51; the second through hole 412 is provided with a protrusion 44, for example, made by hot pressing process, the protrusion 44 lifts the corresponding valve plate 51, which can realize pre-tightening of the valve plate, realize better sealing of the pump cavity 3, and make the outflow of the corresponding valve plate 51 closer to the friction layer 43, so that the columnar liquid or gas is more easily entered into the sensing area of the sensing part 423 and is not easy to stay at the valve plate.

[0079] The working principle of the diaphragm pump is as follows: under the driving of the alternating voltage signal, the piezoelectric wafer 21 drives the diaphragm 2 to periodically bend and vibrate, under the action of the bending vibration of the diaphragm 2, the volume of the cavity 3 will alternately increase and decrease, combined with the one-way valve function of the valve body 4, the working fluid will flow from the inlet 120 to the outlet 110 in one direction. Specifically, when the volume of the pump cavity 3 increases, the pressure in the pump cavity 3 decreases, under the action of the pressure difference, the outlet valve 402 is closed and the inlet valve 401 is opened, and the fluid enters the pump cavity 3 from the second flow channel 12; when the volume of the pump cavity 3 decreases, the pressure in the pump cavity 3 increases, under the action of the pressure difference, the outlet valve 402 is opened and the inlet valve 401 is closed, and the fluid flows from the pump cavity 3 to the first flow channel 11. After the volume of the pump cavity 3 driven by the diaphragm 2 is periodically alternately changed, the working fluid will form a stable one-way flow, realizing the pumping effect of the fluid.

[0080] A channel 31 is arranged in the center of the pump cavity 3. When the channel 31 is arranged in the center and the total volume of the pump cavity 3 (including the channel 31) is equal, the channel 31 can reduce the dead volume (the volume of the area that cannot be covered by the diaphragm vibration) around the periphery of the pump cavity 3, which can improve the working performance of the diaphragm pump. At the same time, according to the flat plate flow theory (for the sake of simplifying the analysis, the fluid passing through the pump cavity 3 is regarded as flat plate flow), since the channel 31 increases the spacing of the flat plate, the channel 31 can reduce the pressure drop of the fluid flowing in the pump cavity, which can reduce the energy loss of the fluid, and further improve the energy conversion efficiency and working performance of the diaphragm pump.

[0081] At the same time, since the valve body 4 is arranged in the channel 31, the design of the channel 31 can make the pump cavity 3 obtain the effect of converging flow, that is, the fluid mainly passes through the channel 31, because the arrangement of the channel 31 can make the cavity height around the periphery of the pump cavity 3 very small, and in the present application, the cavity height around the periphery of the pump cavity 3 is 0.1 mm, which makes it difficult for the working fluid to enter the periphery of the pump cavity 3. During the fluid pumping process, the fluid mainly flows in the channel 31, which can bring many benefits, one is to reduce the retention of other impurities in the pump cavity, and the other is that the columnar bubbles or liquid drops to be detected will flow in the channel 31 from the inlet to the outlet, which is very important for the valve body 4 to monitor the columnar bubbles or liquid.

[0082] Figure 14 、 Figure 15 、 Figure 16 、 Figure 17 The process of the valve body 4 sensing the columnar bubbles in the liquid environment is shown, and it should be noted that the moving direction of the bubbles here is inconsistent with the moving direction in the pump cavity 3, which is mainly used for illustration; Figure 14 is the sensing part 6 area (directly below the sensing part 6 and on the surface of the friction layer 43) where the bubbles have not entered the sensing area 403, Figure 15 is the sensing part 6 area (directly below the sensing part 6 and on the surface of the friction layer 43) where the bubbles have just entered the sensing area 403, Figure 16 is the sensing part 6 area of the sensing area 403, Figure 17 is the sensing part 6 area of the sensing area 403 where the bubbles begin to leave; when the columnar bubbles enter and have not reached the sensing part 6 area, the bubbles move along the friction layer 43, the friction layer 43 and the working fluid (liquid) are in full contact, and the friction layer 43 and the working fluid (liquid) carry equal amounts of negative and positive charges, respectively; as Figure 15As shown, when the cylindrical bubble begins to enter the sensing part 6 area, the originally positively charged liquid in the sensing part 6 area is removed, based on the triboelectric theory, the electrons of the valve body 4 are transferred from the sensing part 6 to the external sensing wire, forming an electrical signal; when the cylindrical bubble completely moves in the sensing part 6 area, the charge amount does not change; when the cylindrical bubble begins to leave the sensing part 6 area, the originally positively charged fluid in the sensing part 6 area is covered again, based on the triboelectric theory, the electrons of the valve body 4 are transferred from the external sensing wire to the sensing part, forming an electrical signal; by monitoring the electrostatic voltage of the sensing part 6, by calculating the time of voltage rise ( Figure 15 , the voltage gradually rises as the bubble begins to enter the sensing area) or calculating the time of voltage drop ( Figure 17 , the voltage gradually drops as the bubble begins to leave the sensing area) and the instantaneous fluid flow rate, the size of the bubble can be monitored, and at the same time, according to the time interval between the voltage rise point and the voltage drop point, the fluid flow in the pump cavity and whether there are impurities retained can be evaluated.

Claims

1. A miniature diaphragm pump with columnar bubble and liquid monitoring functions, comprising a vibrating diaphragm, a substrate, a pump chamber, a valve body, an inlet, and an outlet, characterized in that: The pump chamber is provided with a channel; the channel is connected to the pump chamber; the valve body is installed in the channel; the valve body includes an inlet valve, an outlet valve, and a sensing area; the sensing area is located between the inlet valve and the outlet valve; the sensing area includes a sensing part and a friction layer; the friction layer covers the sensing part.

2. The miniature diaphragm pump with columnar bubble and liquid monitoring functions as described in claim 1, characterized in that: The friction layer is a hydrophobic friction material, and the sensing element is a metal electrode.

3. A miniature diaphragm pump with columnar bubble and liquid monitoring functions as described in claim 1, characterized in that: An insulating membrane is connected to the side of the vibrating diaphragm facing the pump cavity; a piezoelectric crystal is concentrically connected to one side of the vibrating diaphragm.

4. A miniature diaphragm pump with columnar bubble and liquid monitoring functions as described in claim 1, characterized in that: A thin film is provided on the surface of the pump cavity; the thin film has the same hydrophilic and hydrophobic wettability as the friction layer.

5. A miniature diaphragm pump with columnar bubble and liquid monitoring functions as described in claim 1, characterized in that: The valve body is sequentially connected to an upper layer, an intermediate layer, and a friction layer; the upper layer is provided with a first through hole and a second through hole; the friction layer is provided with a third through hole and a fourth through hole; the intermediate layer includes a support part and a mounting area; the mounting area is a hollow area used to install a sensing part; the support part is provided with a first valve part and a second valve part; the sensing part is installed between the first valve part and the second valve part; the first through hole, the first valve part, and the third through hole are coaxially mounted to form an outlet valve; the second through hole, the second valve part, and the fourth through hole are coaxially mounted to form an inlet valve.

6. A miniature diaphragm pump with columnar bubble and liquid monitoring functions as described in claim 1, characterized in that: The height of the channel after the valve body is installed is not less than the height of the pump chamber.

7. A miniature diaphragm pump with columnar bubble and liquid monitoring functions as described in claim 1, characterized in that: The channel is elliptical and cylindrical; the length a of the major semi-axis of the channel is not less than 1.5 times the length b of the minor semi-axis; the length a of the major semi-axis of the channel is not greater than 1 / 2 of the inner diameter of the pump cavity.

8. A miniature diaphragm pump with columnar bubble and liquid monitoring functions as described in claim 4, characterized in that: A protrusion is provided at the third through hole; a protrusion is provided at the second through hole.

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