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Design of valveless type piezoelectric pump for micro-fluid devices
Procedia Chemistry Procedia Chemistry 1 (2009) 353–356 www.elsevier.com/locate/procedia
Proceedings of the Eurosensors XXIII conference
Design of valveless type piezoelectric pump for micro-fluid devices Hyun-Hoo Kima, Jin-Heon Ohb, Jong-Nam Limb, Kee-Joe Limb,*, Dae-Hee Parkc a Department of Display Engineering, Doowon Institute of Technology, Paju, Gyeonggi, South Korea Collage of Electrical and Computer Engineering, Chungbuk National University, Cheongju, Chungbuk, South Korea c Division of Electrical Electronic and Information Engineering, Wonkwang University, Iksan, Jeonbuk, South Korea
b
Abstract
The operation principle of travelling wave rotary type ultrasonic motor can be applied to fluidic transfer mechanism of micro-pump successfully. In this paper, we propose a novel type valveless micro-pump that uses extensional vibration mode of travelling wave as a volume transporting means. The proposed pump is consisted of coaxial cylindrical shells that joined piezoelectric ceramic ring and metal body respectively. To confirm the actuation mechanism of proposed pump model, a numerical simulation analysis on the proposed model was implemented. In accordance with the variation of exciting wave mode and pump body dimension, we analyzed the vibration displacement characteristics if proposed model, determined the optimal design condition, fabricated the prototype pump from the analysis results and evaluated its performance. The maximum flow rate was about 580[µl/min] and the highest back pressure was 0.85[kPa] at 120[Vrms] input voltage. We confirmed that peristaltic motion of piezoelectric actuator was able to be applied to the fluid transferring mechanism of valveless type micro pump effectively through this research. Keywords : Piezoelectric micro-pump; Valveless pump; Extensional vibration mode; Peristaltic motion; Coaxial cylinderical shape pump
1. Introduction Micro-pumps have special characteristics able to transport minute and accurate amount of liquid or gas. Hence, micro-pumps are fit to serve chemical, biological substances analyzing system as micro-fluid flow control appliance.[1] These devices generally consist of a chamber (or chambers) to be created by the deformation of actuator and check valves to manage the fluid flow. But check valves installed in micro-pumps raise problems like pumping performance degradation by abrasion, fatigue and valve blocking etc.[2] In order to solve the critical problems, extensive research and development on valveless type pump have been conducted. Valveless micro-pump, first proposed by Stemme and Stemme, used diffuse / nozzle structure in substitute for the ability of check valves.[3] Also, Yoseph Bar-Cohen et. al, introduced about the peristaltic pump used flexural vibration mode of travelling wave.[4] In this paper, we propose a novel type valveless micro-pump that uses extensional vibration mode of travelling wave as a volume transporting means. The proposed pump is consisted of coaxial cylindrical shells that joined piezoelectric ceramic ring and metal body respectively. The main feature of this pump is not required the valves because the peristaltic action produces to the tightly closed space that can be played and important role as a squeezing effect. And, as the input power is turned off, the sliding interface formed between coaxial shells against each other stops the flow of fluid. Therefore, self-locking action is automatically produced like a closing operation of the conventional check valves. To verify the operation principle of the proposed pump model, a numerical simulation analysis was conducted. Modal and harmonic analyses were carried out for its design. And based on the simulation results, we made a prototype micro-pump and tested its performances. 1876-6196/09/$– See front matter © 2009 Published by Elsevier B.V. doi:10.1016/j.proche.2009.07.088
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H.-H. Kim et al. / Procedia Chemistry 1 (2009) 353–356
2. Actuation mechanism The operation principle of traveling wave rotary type ultrasonic motor can be applied to fluidic transfer mechanism of micro-pump successfully. In a piezoelectric ring of actual motor, the vibration amplitude of traveling wave increases towards the outer perimeter.[5] So, the side wall of elastic body ring installed on the piezoelectric ceramic plate excites the extensional vibration mode in radial direction along the traveling wave propagation. The space formed by this motion is used as a platform for the transportation of fluids. This principle is shown in Fig. 1. The proposed pump is consisted of coaxial cylindrical metal shells bonded annular type piezoelectric ceramic plates. The inner shell is a ring and the outer shells are two semi-circle type parts as shown in Fig. 2. Because the proposed micro-pump uses coaxial cylindrical shells, the slide contact surface between inner and outer shells is able to make chambers through proper operation mode setting.
Fig.1. Vibration mode excitation by travelling wave propagation
Fig.2. Shape of proposed micro-pump model
3. Vibration analysis A numerical simulation analysis on the proposed model was implemented to prove the pump operation mechanism. Finite element modeling software ATILA was used in this process. Modal and harmonic analysis were carried out for inner and outer shells of pump respectively. According to the wave mode and variation of pump body shape, the distribution of vibration amplitude and operational frequency were changed. Fig. 3 shows the deformation of inner and outer shells under the operation condition roughly. When the traveling wave is occurred, excitation of extensional vibration mode in radial direction is confirmed. (white arrows)
Fig.3. Deformation of inner and outer shell (5 wave mode)
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H.-H. Kim et al. / Procedia Chemistry 1 (2009) 353–356
The variation of extensional vibration amplitude and resonance frequency due to the wave mode and elastic body length ratio is presented in Fig. 4 respectively. Body length ratio means the proportion of between height and width of elastic metal body. Analysis on wave mode was executed under 1-length ratio condition, and analysis on length ratio was fulfilled under 5-wave mode condition.
Fig.4. Vibration characteristics
4. Fabrication and performance evaluation of the prototype pump A prototype valveless micro-pump was fabricated in accordance with the simulation result. 5-wave mode and 3length ratio type model was selected because of the high vibration amplitude, low operational frequency characteristics relatively. Piezoelectric ceramic plates made by conventional fabrication method were bonded to the inner and outer metal shells respectively. Piezoelectric ceramics was produced using 0.9Pb(Zr0.51Ti0.49)O30.1Pb(Mn1/3Nb1/3Sb1/3)O3+0.05Cr2O3 composition. To increase the dielectric and piezoelectric properties remarkably, Lead oxide(PbO)-Zirconate(ZrO2)-Titanate(TiO2) and Manganate(MnO2)-Niobate(Nb2O5)-Antimonate(Sb2O3) were mixed.[6] Its prominent properties are shown in Table 1. And components and dimension of a prototype pump are presented in Fig. 5. Table 1. Dielectric and piezoelectric properties of piezoelectric ceramic Measured Item Unit value Electromechanical coupling factor kp % 58 Mechanical quality factor Qm 1500 Piezoelectric constant d33 pC/N 340 d31 -120 pC/N Frequency constant Np 2100 Hz·m Relative dielectric constant 1300 ε /ε 33
0
Inner shell Outer shell
Inner diameter Outer diameter Inner diameter Outer diameter Angle of arc
20[mm] 30[mm] 30[mm] 40[mm] 172°
Fig.4. Components and size dimension of a prototype pump
The performance of proposed micro-pump was measured in terms of flow rate and back pressure that the pump can reach. In case of the acquisition of flow rate data, we used the way measuring the accumulated amount of water by pumping operation for certain period of time. And, the determination of pump back pressure was measured by the height of pumping water into the vertical tube. Maximum flow rate was 580[µl/min] and the highest back pressure was 0.85[kPa] at 120[Vrms] input voltage. Additionally we verified that the fluid flow direction was easily changed
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H.-H. Kim et al. / Procedia Chemistry 1 (2009) 353–356
by the phase control between the two input voltage sources. The flow rate-back pressure characteristic of a prototype micro-pump is shown in Fig. 5.
Fig.5. Flow rate-back pressure characteristic of prototype micro-pump
5. Conclusion In this paper, we proposed the novel type valveless piezoelectric micro-pump that can transport fluid by extensional vibration mode of travelling wave. This pump has the coaxial cylindrical shape of body which can form the multiple chambers due to the vibration. In accordance with the variation of exciting wave mode and pump body dimension, we analyzed the vibration displacement characteristics if proposed model, determined the optimal design condition, fabricated the prototype pump from the analysis results and evaluated its performance. The maximum flow rate was about 580[µl/min] and the highest back pressure was 0.85[kPa] at 120[Vrms] input voltage. We confirmed that peristaltic motion of piezoelectric actuator was able to be applied to the fluid transferring mechanism of valveless type micro pump effectively through this research.
Acknowledgements This work was supported by the Korea Research Foundation Grant funded by the Korean Government (KRF-2008313-D00376.
References 1. Peter Woias, “Micropumps-summarizing the first two decades”, Microfluidics and BioMEMS, Proceedings of SPIE, Vol. 4560, p. 39-52, 2001 2. Yih-Lin Cheng, Jiang-Hong Lin, “Manufacture of three-dimensional valveless micropump”, Journal of Materials Processing Technology 192-193(2007), p. 229-236 3. E. Stemme, G. Stemme, “A valveless diffuser/nozzle-based fluid pump”, Sensor and Actuators A, Vol. 39, p. 159-167, 1993 4. Yoseph Bar-Cohen and Zensheu Chang, “Piezoelectrically Actuated Miniature Peristaltic Pump”, Proceedings of SPIE’s 7th Annual International Symposium on Smart Structures and Materials, 1-5 March, 2000, Newport, CA. Paper No.3992-103 5. T. Sashida, T. Kenjo, “An Introduction to Ultrasonic Motors”, CLARENDON PRESS, OXFORD, p. 127-135, 1993 6. K. Lim, S. Lee, J. Lee, M. Lee and S. Kang, “Piezoelectric and dielectric characteristics of PZT-PMNS ceramics”, Journal of Electroceramics, vol. 13, No. 3, p. 449, 2004
Proceedings of the Eurosensors XXIII conference
Design of valveless type piezoelectric pump for micro-fluid devices Hyun-Hoo Kima, Jin-Heon Ohb, Jong-Nam Limb, Kee-Joe Limb,*, Dae-Hee Parkc a Department of Display Engineering, Doowon Institute of Technology, Paju, Gyeonggi, South Korea Collage of Electrical and Computer Engineering, Chungbuk National University, Cheongju, Chungbuk, South Korea c Division of Electrical Electronic and Information Engineering, Wonkwang University, Iksan, Jeonbuk, South Korea
b
Abstract
The operation principle of travelling wave rotary type ultrasonic motor can be applied to fluidic transfer mechanism of micro-pump successfully. In this paper, we propose a novel type valveless micro-pump that uses extensional vibration mode of travelling wave as a volume transporting means. The proposed pump is consisted of coaxial cylindrical shells that joined piezoelectric ceramic ring and metal body respectively. To confirm the actuation mechanism of proposed pump model, a numerical simulation analysis on the proposed model was implemented. In accordance with the variation of exciting wave mode and pump body dimension, we analyzed the vibration displacement characteristics if proposed model, determined the optimal design condition, fabricated the prototype pump from the analysis results and evaluated its performance. The maximum flow rate was about 580[µl/min] and the highest back pressure was 0.85[kPa] at 120[Vrms] input voltage. We confirmed that peristaltic motion of piezoelectric actuator was able to be applied to the fluid transferring mechanism of valveless type micro pump effectively through this research. Keywords : Piezoelectric micro-pump; Valveless pump; Extensional vibration mode; Peristaltic motion; Coaxial cylinderical shape pump
1. Introduction Micro-pumps have special characteristics able to transport minute and accurate amount of liquid or gas. Hence, micro-pumps are fit to serve chemical, biological substances analyzing system as micro-fluid flow control appliance.[1] These devices generally consist of a chamber (or chambers) to be created by the deformation of actuator and check valves to manage the fluid flow. But check valves installed in micro-pumps raise problems like pumping performance degradation by abrasion, fatigue and valve blocking etc.[2] In order to solve the critical problems, extensive research and development on valveless type pump have been conducted. Valveless micro-pump, first proposed by Stemme and Stemme, used diffuse / nozzle structure in substitute for the ability of check valves.[3] Also, Yoseph Bar-Cohen et. al, introduced about the peristaltic pump used flexural vibration mode of travelling wave.[4] In this paper, we propose a novel type valveless micro-pump that uses extensional vibration mode of travelling wave as a volume transporting means. The proposed pump is consisted of coaxial cylindrical shells that joined piezoelectric ceramic ring and metal body respectively. The main feature of this pump is not required the valves because the peristaltic action produces to the tightly closed space that can be played and important role as a squeezing effect. And, as the input power is turned off, the sliding interface formed between coaxial shells against each other stops the flow of fluid. Therefore, self-locking action is automatically produced like a closing operation of the conventional check valves. To verify the operation principle of the proposed pump model, a numerical simulation analysis was conducted. Modal and harmonic analyses were carried out for its design. And based on the simulation results, we made a prototype micro-pump and tested its performances. 1876-6196/09/$– See front matter © 2009 Published by Elsevier B.V. doi:10.1016/j.proche.2009.07.088
354
H.-H. Kim et al. / Procedia Chemistry 1 (2009) 353–356
2. Actuation mechanism The operation principle of traveling wave rotary type ultrasonic motor can be applied to fluidic transfer mechanism of micro-pump successfully. In a piezoelectric ring of actual motor, the vibration amplitude of traveling wave increases towards the outer perimeter.[5] So, the side wall of elastic body ring installed on the piezoelectric ceramic plate excites the extensional vibration mode in radial direction along the traveling wave propagation. The space formed by this motion is used as a platform for the transportation of fluids. This principle is shown in Fig. 1. The proposed pump is consisted of coaxial cylindrical metal shells bonded annular type piezoelectric ceramic plates. The inner shell is a ring and the outer shells are two semi-circle type parts as shown in Fig. 2. Because the proposed micro-pump uses coaxial cylindrical shells, the slide contact surface between inner and outer shells is able to make chambers through proper operation mode setting.
Fig.1. Vibration mode excitation by travelling wave propagation
Fig.2. Shape of proposed micro-pump model
3. Vibration analysis A numerical simulation analysis on the proposed model was implemented to prove the pump operation mechanism. Finite element modeling software ATILA was used in this process. Modal and harmonic analysis were carried out for inner and outer shells of pump respectively. According to the wave mode and variation of pump body shape, the distribution of vibration amplitude and operational frequency were changed. Fig. 3 shows the deformation of inner and outer shells under the operation condition roughly. When the traveling wave is occurred, excitation of extensional vibration mode in radial direction is confirmed. (white arrows)
Fig.3. Deformation of inner and outer shell (5 wave mode)
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H.-H. Kim et al. / Procedia Chemistry 1 (2009) 353–356
The variation of extensional vibration amplitude and resonance frequency due to the wave mode and elastic body length ratio is presented in Fig. 4 respectively. Body length ratio means the proportion of between height and width of elastic metal body. Analysis on wave mode was executed under 1-length ratio condition, and analysis on length ratio was fulfilled under 5-wave mode condition.
Fig.4. Vibration characteristics
4. Fabrication and performance evaluation of the prototype pump A prototype valveless micro-pump was fabricated in accordance with the simulation result. 5-wave mode and 3length ratio type model was selected because of the high vibration amplitude, low operational frequency characteristics relatively. Piezoelectric ceramic plates made by conventional fabrication method were bonded to the inner and outer metal shells respectively. Piezoelectric ceramics was produced using 0.9Pb(Zr0.51Ti0.49)O30.1Pb(Mn1/3Nb1/3Sb1/3)O3+0.05Cr2O3 composition. To increase the dielectric and piezoelectric properties remarkably, Lead oxide(PbO)-Zirconate(ZrO2)-Titanate(TiO2) and Manganate(MnO2)-Niobate(Nb2O5)-Antimonate(Sb2O3) were mixed.[6] Its prominent properties are shown in Table 1. And components and dimension of a prototype pump are presented in Fig. 5. Table 1. Dielectric and piezoelectric properties of piezoelectric ceramic Measured Item Unit value Electromechanical coupling factor kp % 58 Mechanical quality factor Qm 1500 Piezoelectric constant d33 pC/N 340 d31 -120 pC/N Frequency constant Np 2100 Hz·m Relative dielectric constant 1300 ε /ε 33
0
Inner shell Outer shell
Inner diameter Outer diameter Inner diameter Outer diameter Angle of arc
20[mm] 30[mm] 30[mm] 40[mm] 172°
Fig.4. Components and size dimension of a prototype pump
The performance of proposed micro-pump was measured in terms of flow rate and back pressure that the pump can reach. In case of the acquisition of flow rate data, we used the way measuring the accumulated amount of water by pumping operation for certain period of time. And, the determination of pump back pressure was measured by the height of pumping water into the vertical tube. Maximum flow rate was 580[µl/min] and the highest back pressure was 0.85[kPa] at 120[Vrms] input voltage. Additionally we verified that the fluid flow direction was easily changed
356
H.-H. Kim et al. / Procedia Chemistry 1 (2009) 353–356
by the phase control between the two input voltage sources. The flow rate-back pressure characteristic of a prototype micro-pump is shown in Fig. 5.
Fig.5. Flow rate-back pressure characteristic of prototype micro-pump
5. Conclusion In this paper, we proposed the novel type valveless piezoelectric micro-pump that can transport fluid by extensional vibration mode of travelling wave. This pump has the coaxial cylindrical shape of body which can form the multiple chambers due to the vibration. In accordance with the variation of exciting wave mode and pump body dimension, we analyzed the vibration displacement characteristics if proposed model, determined the optimal design condition, fabricated the prototype pump from the analysis results and evaluated its performance. The maximum flow rate was about 580[µl/min] and the highest back pressure was 0.85[kPa] at 120[Vrms] input voltage. We confirmed that peristaltic motion of piezoelectric actuator was able to be applied to the fluid transferring mechanism of valveless type micro pump effectively through this research.
Acknowledgements This work was supported by the Korea Research Foundation Grant funded by the Korean Government (KRF-2008313-D00376.
References 1. Peter Woias, “Micropumps-summarizing the first two decades”, Microfluidics and BioMEMS, Proceedings of SPIE, Vol. 4560, p. 39-52, 2001 2. Yih-Lin Cheng, Jiang-Hong Lin, “Manufacture of three-dimensional valveless micropump”, Journal of Materials Processing Technology 192-193(2007), p. 229-236 3. E. Stemme, G. Stemme, “A valveless diffuser/nozzle-based fluid pump”, Sensor and Actuators A, Vol. 39, p. 159-167, 1993 4. Yoseph Bar-Cohen and Zensheu Chang, “Piezoelectrically Actuated Miniature Peristaltic Pump”, Proceedings of SPIE’s 7th Annual International Symposium on Smart Structures and Materials, 1-5 March, 2000, Newport, CA. Paper No.3992-103 5. T. Sashida, T. Kenjo, “An Introduction to Ultrasonic Motors”, CLARENDON PRESS, OXFORD, p. 127-135, 1993 6. K. Lim, S. Lee, J. Lee, M. Lee and S. Kang, “Piezoelectric and dielectric characteristics of PZT-PMNS ceramics”, Journal of Electroceramics, vol. 13, No. 3, p. 449, 2004