Valveless Pumps

Jun TK, Kim CJ (1998) Valveless pumping using traversing vapor bubbles in microchannels. J Appl Phys 83 5658-5664... 

Diaphragm pump Flexible member pump Membrane pump Valveless pumps... 

In Chapter 9, we move on to discuss a few device and robotic applications of EAP materials, by drawing heavily on the advances in material development and modeling that are discussed in prior chapters. These application examples include a robotic fish propelled by an IPMC tail, an IPMC energy harvester, an IPMC-based valveless pump, a conjugated polymer petal-driven micropump, and a synthetic elastomer actuator-enabled robotic finger. Most discussions of these examples are supported with extensive experimental results. 

In this chapter, we extend and apply the results on EAP materials and models to a few device and robotic applications. A robotic fish propelled by an IPMC caudal fin is first considered in Section 9.1. The use of IPMC for low-frequency energy harvesters is studied in Section 9.2. The design of an IPMC-enabled valveless pump is discussed in Section 9.3. We then present a novel micropump actuated by conjugated polymer petals, supported by both analytical and experimental results. Finally, in Section 9.5 we investigate the design, prototyping, and control of a robotic finger powered by dielectric elastomer actuators. 

Figure 5.19 — Flow-through biochemical sensor based on the twofold immobilization of the catalyst (urease) and reagent (an acid-base azo dye) in the sensing microzone for the determination of urea in kidney dialysate. (A) Sensing microzone held in a microcircuit. (B) Valveless flow injection manifold. P pumps T timer S sample W waste. For details, see text. (Reproduced from [57] with permission of Elsevier Science Publishers).

Urea in kidney dialysate can be determined by immobilizing urease (via silylation or with glutaraldehyde as binder) on commercially available acid-base cellulose pads the process has to be modified slightly in order not to alter the dye contained in the pads [57]. The stopped-flow technique assures the required sensitivity for the enzymatic reaction, which takes 30-60 s. Synchronization of the peristaltic pumps PI and P2 in the valveless impulse-response flow injection manifold depicted in Fig. 5.19.B by means of a timer enables kinetic measurements [62]. Following a comprehensive study of the effect of hydrodynamic and (bio)chemical variables, the sensor was optimized for monitoring urea in real biological samples. A similar system was used for the determination of penicillin by penicillinase-catalysed hydrolysis. The enzyme was immobilized on acid-base cellulose strips via bovine serum albumin similarly as in enzyme electrodes [63], even though the above-described procedure would have been equally effective. 

Seiler, K., Fan, Z.H., Fluri, K., Harrison, D.J., Electroosmotic pumping and valveless control of fluid flow within a manifold of capillaries on a glass chip. Anal. Chem. 1994, 66, 3485-3491. 

The mash is conveyed from the fruit mill to the press, and to and from the heat exchanger, by means of valveless eccentric spiral pumps, large impeller pumps or slow-running piston pumps. 

Normal IC separations rely on a high-pressure eluent pump, injection valve, column and detector. However, a novel method for speciation was developed by Gjerde and Wiederin [4], in which a low-pressure column, valveless injection method was employed. The system configuration is shown in Fig. 11.1. An example with this type of IC to perform a separation of Cr(III) and Cr(IV) is shown in Fig. 11.2. Nitric acid eluent is acceptable in this case because it does not oxidize Cr(III). The separation method is anion exchange, so Cr(III) is unretained and Cr(IV) is eluted by the nitrate... 

Figure 11.2. Separation of Cr(IIl) and Cr(VI) by valveless IC and JCP-MS detection. The separation is affected by both the volume of sample introduced to the column and the speed of the peristaltic pump. The eluent was 0.35 % (w/w) nitric acid adjusted to pH 1.6 with ammonium hydroxide. The column is a low-capacity anion exchanger ANX3202 with dimensions of 3.2 x 20 mm. Detection limits for Cr(IlI) and Cr(Vl) are both <0.1 ppb. Courtesy of Transgenomic, Inc., Omaha, NE.

E. Stemme, G. Stemme, A valveless diffuser/nozzle-based fluid pump, Sensor Actuator A — Phys. 39 (1993) 159. 

J.H. Zhang, J.H. Lu, Q.X. Xia, H. Li, Theoretical analysis and experimental investigation of valveless piezoelectric pumps with unsymmetrical ridges, Front. Mech. Eng. China 2 (2007) 13. 

Rife JC, Bell MI, Horwitz JS, Kabler MN, Auyeung RCY, Kim WJ (2000) Miniature valveless ultrasonic pumps and mixers. Sens Actuator 868 135-140... 

J. C. Rife, etal,. Miniature Valveless Ultrasonic Pumps and Mixers Sens., Actuators A, 2000, 86, 135-140. 

LOCA (primary) Leak before break concept and lifetime monitoring of pressure tubes and heat transport system piping and components (L) Division into two loops (L) Reactor coolant pumps with multiple mechanical seals (R) Valveless system (S)... 

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