Together we will find a solution for your problem. Bio-inspired applications include a flexible electromagnetic micropump using magnetorheological elastomer to replace lymphatic vessels. In addition, by comparing the flow characteristics of different double-loop tubes, it can be concluded that the rectification effect of double-loop tubes with a square cross section is much better. The membrane is positioned above a main pump valve, which is centered between inlet and outlet microvalves. Flow rate is adjustable by changing drive voltage or drive frequency. Konrad-Adenauer-Allee 11 Accordingly, the energy loss of fluid at each part is as follows: (A2) EiEi=E1E1E2E2E3E4E5E3E4E5=121u121((u2)2+(u3)2)2u222((u4)2+(u6)2)3u323((u5)2+(u7)2)4(u42+u52)4(u8)25(u62+u72+u82)5(u9)2,(A2) where Ei and Ei are the energy loss at Part i in the expanding direction and in the contracting direction, respectively, and ui and ui are the velocities of the fluid at cross section i-i, as shown in FigureA1. Non-mechanical pumps function with electro-hydrodynamic, electro-osmotic, electrochemical [14] or ultrasonic flow generation, just to name a few of the actuation mechanisms that are currently studied. HVC Series Valves, Live Cell Imaging Fluidic System However, it flows through the middle passage in the contracting direction. The following results were obtained: The novel double-loop flow tube had the function of rectification. As for the pumps with circle cross section tubes, Pump A (d=1.5mm) and Pump B (d=2.0mm) had maximum amplitudes of 41 and 52m, respectively, at 7Hz. Figure13 is the amplitude measuring result on the surface of the vibrator. The current alternative to the micropump the fan has numerous drawbacks. To say is that all of our mp6 micropumps are able to promote liquids, mixtures and gases. People also read lists articles that other readers of this article have read. Table 4. Static valves are defined as valves which have fixed geometry without any moving parts. From Equation (3), we know that the change in the square cross section size has a greater influence on the rectification effect in the expanding direction, compared with that of a circular cross section. As shown in Figure9, the function signal generator (AFG1022, Tektronix, Beaverton, WA, USA) provided a sinusoidal signal, which was amplified by a power amplifier (HAS4051, NF, Yokohama, Japan) and applied to the piezoelectric vibrator. Afterwards, under the excitation voltage of 100V RMS (effective voltage), the performances of six pumps were tested. In addition, there was the center of the vortex (marked with a circle), which is consistent with what was explained in Section 2.2.1. Afterwards, the piezoelectric vibrator was applied with the same voltage excitation as before. The upper surface of the pump chamber is covered by a piezoelectric vibrator. Artificial sphincter technology based on the titanium micropump ensures continence by automatically adjusting the pressure during laughter or coughing. As for the reason, this phenomenon can be explained by the inertia of fluid and the energy dissipation of vortexes.
What is more, fluid inertia is the main factor affecting the rectification effect.
The structural parameters of the vibrator are shown in Table5. Chemically powered non-mechanical pumps have been fabricated by affixing nanomotors to surfaces, driving fluid flow through chemical reactions. In order to prove the double-loop tubes function of rectification, an experiment was carried out as shown in Figure8. E-Mail: info@bartels-mikrotechnik.de, Microfluidic Chips for full systemic functionality, liquids: controlable flowrate 8 l/min up to 10.000 l/min, typ.
Figure A1. The pump body includes a pump chamber and double-loop tubes. Head over to our YouTube channel to find a variety of videos centered around the mp6 micropump and additional components and accessories. Figure 13. In addition, during the experiment, mechanical fatigue may occur due to the constant vibration of the vibrator, which changes the stiffness of structure and results in the offset of the resonance point. At the same time, we used a laser displacement sensor (LK-H020, Keyence, Osaka, Japan) to measure the vibration of the vibrator. In order to eliminate the influence of the height difference on the output performance of VPMGRFs, performance tests were carried out under the initial conditions of zero back pressure. Then, the flow field in a double-loop tube was simulated and the flow characteristics of double-loop tubes with different cross section shapes and areas were investigated. [3][4] Although any kind of small pump is often referred to as micropump, a more accurate definition restricts this term to pumps with functional dimensions in the micrometer range. (11) Ec=E0c(11) (12) Ee=E0e,(12) where Ec and Ee are the energy losses in the contracting and expanding directions, respectively, and c and e are the coefficients of energy loss in the contracting and expanding direction, respectively. Microdosing device with several scent reservoirs that are mounted near the nose can release 15 different scent impressions in 1 min. Silicon micropumps at Fraunhofer EMFT are manufactured by silicon micromachining technology. We aim to offer you the best products possible, should this on any occasion not be the case, do not hesitate to contact us! With the function of rectification, double-loop tubes can be regarded as valve bodies with nonmoving parts. Before applying power excitation, the liquid level of the two beakers was the same and both of them held deionized water with a dye that does not spread easily. The specific derivation process is given in Appendix A. Moreover, we can conclude that fluid in the side passage flowed towards the expanding direction macroscopically. [38][39] Certain nanoparticles are able to convert light from a UV source to heat which generates convective pumping. As shown in Figure6(b), during the discharge process, the vibrator is moving downwards, the pump chamber is compressed, and the fluid is pressed out from the pump chamber. The pump diaphragm expands with application of a negative voltage to the piezo thus creating negative pressure to suck the fluid into the pump chamber. Consequently, the following relationships can be obtained: (A4) u1=u9(A4) (A5) u2=u3u4=u5u6=u7u6=Ku4u7=Ku5(A5) (A6) u2=u3u4=u5u6=u7u8=Ku6=Ku7,(A6) where K and K are dimensionless constants. In addition, when x is larger, it indicates that the fluid is more inclined to flow along a certain flow path. Additionally, the bonding layer might be affected by the pumped medium. 15 correspond to Parts A E, respectively.
As the pumping goes on, the movement trajectory and direction of microspheres are shown by the curves with arrows. During the pumping process, the kinetic energy of the vibrator will translate into the kinetic energy of the fluid due to the fluidstructure interaction.
Rectification effect of fluid in the contracting direction. It was obvious that the larger the characteristic length, the greater the amplitude of pressure. Our micropumps can be used in many different ways in medical and analytical technology, mechanical engineering, space research and many other applications. Experimental setup for the flow field during a pumping cycle. The direction of polarization of the ceramic disc is along the length. As shown in Figure6(a, b), due to the rectification of the double-loop tube, fluid flows along different paths during the suction and discharge processes. To make sure that the flows in different directions have the same initial velocity, the liquid level difference was set to 10cm. Quality is our top priority. The right beaker had red dye added to it, while the left had black dye added. By comparing the pumps with different cross section shapes of double-loop tubes, it can be concluded that the pumps with circular cross section double-loop tubes performed better in terms of the flow rate. by means of portable devices within telemedicine programs. valve flaps, do not exhibit wear and fatigue.
Figure15 shows the results of net flow rate over time. They will contribute to form Helmholtz discontinuity and generate vortexes, constantly consuming the kinetic energy of the fluid and slowing down the flow in consequence. The subscript x represents the direction of the fluid flow. Piezoelectric driven micropumps rely on electromechanical property of piezo ceramic to deform in response to applied voltage.
The flow rate is controlled by the polarization limit of the material and the voltage applied on the piezo. Variable flow rate adjustment guarantees a wide range of possible applications. After that, the positions of the two beakers were interchanged so as to change the direction of flow through the double-loop tube. 3099067 Relationship between the instantaneous output pressure of pumps and time. 0 It should be noted that (Q66)x and (Q88)x in Equation (1) are obtained from the same direction of fluid movement. This will intensify the shear stress in the fluid layer, which results in obvious energy loss. It was measured at 20, 40, and 60s. We took the average as the net flow rate and calculated the error bar. Recommended articles lists articles that we recommend and is powered by our AI driven recommendation engine. This pump is a larger size than the standard type to pump a more significant flow rate. The theoretical model of vibration, the fluid dynamics, and the net flow rate were established. [9] Most of the fundamental MEMS micropump work was done in the 1990s. A wide variety of pumping systems exist including biological enzyme based pumps,[28][29][30][31][32][33] organic photocatalyst pumps,[34] and metal catalyst pumps. Mit dem Laden des Videos akzeptieren Sie die Datenschutzerklrung von YouTube.Mehr erfahren. Table 3. As shown in FiguresA1A6, the fluid flowed through the side passage of the double-loop tube in the expanding direction because the silicon carbide powders (marked with arrows) in the middle passage were barely moving. This process is repeated to pump fluid continuously.
The nonmoving parts are based on the flow resistance mechanism to realize unidirectional fluid pumping macroscopically. To simplify the flow model, unsteady NavierStokes equations were used to deal with a steady model invariant over time, based on the Reynolds-averaged NavierStokes (RANS) model. Furthermore, nonmoving parts include conical tubes (He et al., 2017; Tseng et al., 2013), Y-shaped tubes (Huang et al., 2013, 2016), heterotypic tubes (Izzo et al., 2007), spiral tubes (Leng et al., 2013), vortex diodes (Huang et al., 2019), unsymmetrical chambers with blocks arranged (Xia et al., 2012), etc. Measuring result of the output pressure amplitude: (a) Output pressure amplitude of pumps with different circle cross-section tubes under a fixed voltage; (b) Output pressure amplitude of pumps with different circle cross-section tubes under the a fixed frequency; (c) Output pressure amplitude of pumps with different square cross-section tube under a fixed voltage; (d) Output pressure amplitude of pumps with different square cross-section tubes under a fixed frequency.
The flow rate of the micropumps shows a linear dependency on the back pressure.At 0 mbar back pressure the maximum flow rate can be achieved and at the maximum back pressure the flow rate is decreased to 0 ml/min. The fields of application for piezoelectric micropumps are in laboratory technology, medical technology, biotechnology, chemical analytics, and process technology, which require reliable metering of minute amounts of liquids and gases. When AC excitation was applied to the vibrator, the liquid in the right beaker began to flow along the silicone tube towards the left beaker and the reading on the precision balance gradually increased. Figure 18. Micro Pumps for Infusion/Drug Delivery Systems Experiment schematic of double-loop tube. Then, the standard deviation is used to represent the stability: (2) 2=1Ni=1N(xix)2,(2) where xi is the flow rate ratio, xi represents the characteristic length, and x is the average value of xi. [15], By closing this message, you are consenting to our use of cookies.
Hence, it had the function of pumping the fluid in a single direction, along the expanding direction. Among the common microfabrication processes, the following techniques can be named: photolithography, anisotropic etching, surface micromachining and bulk micromachining of silicon. The micropumps are offered individually and in evaluation sets. flow rate 20 ml/min & typ. As an alternative to silicon polymer-based materials like PDMS, PMMA, PLLA, etc. Pump F (l=2.5mm) had a maximum value of 165m at 6Hz. To verify the rectification of the double-loop tube, we had to provide a driving power for the fluid to flow through the double-loop tube. More recently, efforts have been made to design non-mechanical micropumps that are functional in remote locations due to their non-dependence on external power. Figure12 shows the results of observation of the flow field in VPMGRF. Moreover, the distance between the chamber outlet and the chamber center is 2mm, and the radius of the bent tubes is 2.5mm. Larger strokes or forces can be achieved if a diaphragm or a piston is coupled directly to a piezoelectric actuator. Therefore, the dimensionless parameter x in Equation (1) will be influenced by the liquid level difference of h. Physical drawing of six sets of sample pumps.
Glass capillaries and porous media, including nitrocellulose paper and synthetic paper,[23] can be integrated into microfluidic chips. Therefore, we selected a minimum characteristic length of 1.5mm and an interval of 0.5mm. When the membrane is deflected upwards through some driving force, fluid is pulled into the inlet valve into the main pump valve. On the other hand, the amplitude of the vibrator increased slowly in a certain voltage range. [12] Mechanical systems contain moving parts, which are usually actuation and microvalve membranes or flaps. Pump A (d=1.5mm) and Pump B (d= 2.0mm) had the maximum net flow rate of 5.19 and 4.77mL/min, respectively, at 8Hz. The fluid passing through the side passage during the suction process will flow through the middle passage during the discharge process. As there are machining size errors in the actual manufacturing process of the tubes, it is necessary to analyze the stability of the rectification effect when the characteristic length of the cross section changes. Considering contemporary state of air pollution one of the most promising applications for micropump lies in enhancement of gas and particulate matter sensors for monitoring personal air quality. Figure 12. Nagoya, Aichi 458-8522, Japan Accordingly, the motion of any point over the vibrator can be obtained: (5) H=H(r,)sin2ft(5) (6) H=dHdt(6) (7) H=dHdt,(7) where H, H, and H are the displacement, velocity, and acceleration of any point on the vibrator; H(r,) is the maximum amplitude of a location on the vibrator; f is the frequency of the excitation source; and t is the time. Simulation results of flow rates through cross sections 66 and 88 are viewed regarded as the flow rates through the side passage and the middle passage, respectively. Dimensional parameters of double-loop tubes. Register to receive personalised research and resources by email. As shown in Figure10, the flow trajectory of the fluid in a double-loop tube during a pumping cycle was observed. Moreover, the structure of the double-loop tube is symmetrical. Tel: +49-231-47730-500 These sets allow you to gain application-specific experience and cost-effectively reduce your integration efforts. From the above simulation results, it can be concluded that a double-loop tube provides the function of rectification.
Within analytical systems, the micropump can be for lab-on-chip applications, HPLC and Gas Chromatography systems etc. As shown in Figure6(a), during the suction process, the vibrator is moving upwards, the pump chamber is expanding, and the external fluid is inhaled through double-loop tubes. Thus, the variation in pressure amplitude with respect to frequency and voltage could be obtained as shown in Figure18.
[19] The compression ratio of Fraunhofer EMFT micropumps reaches the value of 1, which implies self-priming capability and bubble tolerance even at challenging outlet pressure conditions. Such pumps are of special interest in microfluidic research, and have become available for industrial product integration in recent years. The vibrator arches up in the center and the surface of deformation can be considered a paraboloid. The compression ratio of the micropump as one of the critical performance indicator is defined as the ratio between the stroke volume, i.e. This is because they are produced in a certain sequence, rather than at the same time. When the excitation source applied to vibrator is constant, the greater the output pressure, the smaller the flow rate. Application of the Fraunhofer EMFT piezoelectric micropump reduces reaction time of the sensor up to 2 seconds through fast sampling of the ambient air. To further explore the relationship between the fluid inertia and the rectification effect, six different sets of double-loop tubes with different cross section shapes and areas were designed. As shown in FigureA1, the double-loop tube can be divided into five parts, namely Part A, Part B, Part C, Part D, and Part E. According to the method of nodal analysis, the energy losses of fluid flowing through each part are analyzed. Table 5. In order to get in touch with us, please feel free to use our contact form. Currently mechanical micropump technology extensively uses Silicon and Glass based micromachining processes for fabrication. In addition, the trends of net flow rate curves were similar to those of amplitude curves in Figure14. The pump bodies were made of transparent photosensitive resin by SLA (Stereo lithography Apparatus), as shown in Figure7. The dimensional parameters are shown in Table2. The deformed surface area of the vibrator can be obtained by measuring the amplitudes of nine points over the vibrator. Microdiaphragm pumps require compact drives that can provide a continuous flow and variable flow rates. Different cross section shapes and characteristic lengths had an influence on its rectification. The compression ratio defines the bubble tolerance and the counter pressure capability of the micropumps. We use cookies to improve your website experience. Biotechnology, Thruster Valves for Satellite Propulsion Systems, HVA/HVAL Series Valves The flow characteristics among different lengths is almost consistent when the fluid flows in the contracting direction.
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