Miniature solenoid valves’ continued evolution makes them valuable and effective components for controlling the flow, direction and pressure of gases and fluids.
Paul Gant, Emerson Automation Solutions
With automated functions, excellent reliability and long life, it’s no surprise that gas and liquid valves are used throughout the medical device industry. They control the flow, direction and pressure of the gases or fluids used by a device.
Miniature valves and the electronics that control them provide performance, longevity and dependability for oxygen concentrators, ventilators and respirators, anesthesia equipment, patient monitors, clinical diagnostics, DNA sequencing, surgical equipment and even dialysis.
Recent improvements in solenoid-operated valves are helping medical device manufacturers use energy much more efficiently, allowing them to build more portable equipment while managing issues such as heat generation more effectively.
Solenoid-operated valves are commonly used in oxygen therapy devices because they offer value and reliability while providing excellent function. Pressures in medical device applications are typically lower than industrial applications — often 1 bar (14.5 psi) and much less. Proportional control, or the ability of a valve to vary its orifice size based upon the strength of a signal, gives further capability while enabling multiple uses. Combined with a “smart” electronic control system, these valves can deliver exacting solutions and may also perform different functions to expand the capability of specialized machinery.
Isolation valves are used in applications where fluid control must be efficient, precise and leak-free. These applications require the fluid to be contained and often be controlled without contamination from outside elements, including the valve itself. In many cases, a membrane is used to accomplish the isolation, with many different design elements and functions for the unique application. An alternative design is a pinch valve control, which allows fluid to flow through a soft tube while the valve controls the medium by “pinching” the tube. In this case, purity of the medium is ensured.
Solenoid and other miniature valves offer medical device designers several technical advantages, including the following:
One of the leading reasons solenoid valves and other miniature fluidic components have long been used in medical devices is that they combine lightweight construction with a simple, compact design to enhance medical device portability. Newer solenoid valve technology provides manufacturers with the ability to custom-configure standard solenoid valve components to fit more readily into tight device configurations, reducing weight without sacrificing function.
Solenoid valves are electrically powered, leading to two important design considerations: power consumption and heat control. Newer solenoid valves are typically available in a broad range of power profiles. If a 3.3-volt coil is the best fit for a particular valve, it is usually available as a standard variation. This means designers can better match the solenoid valve to the power capacity of the medical device, which can help extend battery life on portable devices and can also help control the heat generated within the medical device.
The compact, simple design of many solenoid valves makes them especially useful for manufacturers who are developing pilot projects and need the ability to scale the production run of the end product up or down. Solenoid valves can be easily integrated into manifolds and other electropneumatic control subassemblies whose production can be cost-effectively scaled.
Medical device manufacturers can benefit from the integration of microelectronics during valve manufacturing to help make their devices more intelligent while also enabling them to use a variety of digital communications protocols, such as Ethernet/IP or Profinet. Miniature electronic, proportional valves combined with the proper electronic controls and feedback can control pressure, flow and other variables in a medical device. These closed-loop systems enable the engineer to design complex system controls while still relying on the valve manufacturer to deliver a robust, affordable package.
The healthcare industry’s use of digital information from medical devices to help track and assess patient therapy outcomes continues to expand. Digital technology that is now incorporated into solenoid valves can help document how the operation of medical devices contributes to these outcomes. This information can become part of the digital record of a patient’s treatment, ultimately helping to ensure medical devices are properly providing the targeted therapy. Medical device designers can take advantage of these capabilities and use them to provide a competitive edge in their systems’ performance.
Custom design support
Many suppliers of miniature gas and liquid control valves have standard product portfolios. However, medtech manufacturers with unique design challenges such as portability, energy-efficiency, scalability and use of digital data, may benefit from working with suppliers who develop customized solenoid valve configurations. Such suppliers should have engineering resources available to quickly adapt standard products to custom configurations, familiarity with integrating electronics into miniature control solutions and experience with integrating solenoid valves into complete subassemblies.
Paul Gant is director of business development, Analytical & Medical, for Emerson Automation Solutions. He previously served as director of global life sciences for Aventics and worked in sales management for Clippard for 19 years.
The opinions expressed in this blog post are the author’s only and do not necessarily reflect those of Medical Design and Outsourcing or its employees.