For people with chronic respiratory ailments, ventilators and oxygen apparatus are an essential everyday companion. Inside the machines, which are often portable, pneumatic automation components ensure a smooth ventilation process—they generate the required pressure and correct mix of oxygen.
Piezo valves from Festo are used in modern ventilators to supply the oxygen, and they provide major benefits compared to the previous solenoid valve technology. First, piezo valves consume up to 95% less electrical power. This is particularly important on the portable appliances—the batteries therefore last much longer, which save the patient from changing them frequently. Second, due to the proportional nature of piezo valves, they can be configured to supply very fine doses, allowing oxygen to be mixed in exact quantities. Last but not least, the switching operation makes very little sound, so patients who have to be ventilated day and night are not disturbed by the much quieter operation.
How piezo technology works
Some ceramic materials are deformed when they are placed under an electric charge—two plates made of such a material and joined together are then bent, for example, in a certain direction. Festo makes use of this process for its piezo valves. They are opened and closed with the help of this small connected plate, the bending actuator.
If voltage is applied to the bending actuator, the ceramic layer contracts and bends the small plate upwards; the valve opens (figure right). If the voltage is switched off, the bending actuator resumes its original shape and closes the valve (figure left). The higher the voltage, the wider the valve opens—the rate of flow can thus be regulated. These switching operations can be repeated very quickly with Piezo valves.
Piezo valves are also used in many other medical areas such as decubitus mattresses to prevent bedsores, blood pressure gauges, and laboratory appliances. The fast switching and small dimensioned valves are also used in the automotive and semiconductor industries, food processing, and other industrial automation applications.
Guest blog submitted by: Frank Langro, Festo Corporation, Director – Marketing and Product Management, Festo.
Filed Under: Actuators, Pneumatic equipment + components, Food + beverage