Solenoid Valves

As their name suggests, solenoid valves are electro-mechanical valves. Depending on the mode of the valve, the plunger in the rest position either plugs the orifice or remains open. But when the solenoid coil is energized, the magnetic field created by the solenoid changes the plug’s position. This mechanism allows for the fast and automatic control of the flow of fluids. Remote control is possible with a mere electrical switch, thus facilitating extremely important applications in both medical devices and other bioengineering applications!

Self-Assessment Questions:

Click here to test your understanding of solenoid valves.

Discussion Questions:

1. How is a solenoid different from an inductor? What aspects of their design give rise to these differences and how does that affect their use in circuits?
2. Solenoid valves can either be designed to be “normally open” or “normally closed”. How would the design of the valve differ for each? In what state does the current run through the solenoid in each?
3. Although not extremely expensive, solenoid valves are more expensive than most passive circuit components. Do you think the solenoid or the valve part of the component contributes more to the cost and why? How might these costs be driven down in manufacturing of these components? Use this article by Hulme et al. to help answer the question.
4. The video focused on the more basic two-way solenoid valve. However, three-way solenoid valves are also used. When might it be advantageous to use a three-way solenoid valve instead of a two-way valve? How are the designs different? Use this article as a starting point for differences between the two types. Also check out the linked blog post at the end of the resources!
5. The main application of solenoid valves is in fluidics control. Find three devices in which fluid flow control is necessary in bioengineering, and explain how solenoid valves are used in each case. Use this article by Sardellitti et al. as a starting point.
6. Microvalve-based bioprinting has shown preliminary promise as a method for controlling the 3D printing of cells and hydrogel scaffolds. Using this article by Ng et al., list some advantages and disadvantages of this technology. Do you think this will become the principal way of creating precision cellular biomaterials in the coming years? Why or why not?

Continue Reading:

• S. E. Hulme, S. S. Shevkoplyas, and G. M. Whitesides, “Incorporation of prefabricated screw, pneumatic, and solenoid valves into microfluidic devices,” Lab Chip, vol. 9, no. 1, pp. 79–86, 2009. Read this resource here.
  • This article outlines methods for fabrication of screw, pneumatic, and solenoid valves, as well as how to embed them in microfluidic devices that control chemical gradients. The costs associated with these components and techniques are also addressed.
• H.-S. Jeong and H.-E. Kim, “Experimental based analysis of the pressure control characteristics of an oil hydraulic Three-Way on/off solenoid valve controlled by PWM signal,” J. Dyn. Syst. Meas. Control, vol. 124, no. 1, pp. 196–205, 2002. Read this resource here.
  • This article discusses the process as well as the advantages and disadvantages of using pulse wave modulation (PWM) as a control mechanism for two and three way valves. These different valve types are also explained.
• I. Sardellitti, S. Cecchini, S. Silvestri, and D. G. Caldwell, “Proportional mechanical ventilation through PWM driven on/off solenoid valve,” Annu Int Conf IEEE Eng Med Biol Soc, vol. 2010, pp. 1222–1225, 2010. Read this resource here.
  • This article details the use of a simple two-way valve in mechanical ventilation, describing the advantages of such a mechanism and how it was optimized for the given application.
• W. L. Ng, J. M. Lee, W. Y. Yeong, and M. Win Naing, “Microvalve-based bioprinting – process, bio-inks and applications,” Biomater. Sci., vol. 5, no. 4, pp. 632–647, 2017. Read this resource here.
  • Microvalve based bioprinting provides precision control in bioprinting applications where continuous extrusion is not desired. This article explains the principles by which this technology works using solenoid valves and lists some of the advantages and disadvantages as it is studied further.

Note: Although not a scholarly article, this blog post provides some good visuals about two and three way valves!  It also discusses the differences between two and three-way solenoid valves as well as the different types of three-way solenoid valves and how their applications may differ.

About the Creator:

This video was created by a student in the Rice Bioengineering Class of 2021 (used with permission).