Mixing and dosing gases – four applications, one solution
The mass flow controller VEMD is precise, efficient and versatile
Precisely mixing and dosing gases plays a decisive role in many areas, whether in life sciences, machine building or food & packaging. The proportional flow control valve VEMD is the cost-effective solution provided by Festo for a wide range of applications. Let's take a look at four examples.
The VEMD is a closed-loop, thermal mass flow controller that precisely supplies inert gases and oxygen with flow rates from 0 to 20 ln/min. Its piezo technology delivers an industry-leading dynamic response and energy efficiency, all at an excellent price/performance ratio. Since no pulse width modulation signal is required to control the flow rates, the VEMD is quiet during operation. Thanks to its compact installation dimensions, low weight and low energy consumption, it is ideal for use in mobile devices, as the first application example shows.
Mobile oxygen therapy for greater quality of life
Patients with pulmonary hypertension and chronic respiratory arrest are not able to absorb the amount of oxygen necessary for daily life. They therefore benefit from Home Oxygen Therapy (HOT). Using a mobile oxygen concentrator and a nasal cannula, patients can inahle oxygen at a concentration of 90%. For comparison: The oxygen concentration in the air lies around 20%.
In the past, this type of treatment required regular hospitalization. Thanks to mobile oxygen therapy, patients can now stay home and enjoy a much larger range of actions.
The VEMD is used in light and safe oxygen concentrators, where it ensures the oxygen is precisely dosed and at exactly the right time for the patient's breathing. Again, the most important criteria are quiet operation, suitability for oxygen, energy efficiency, low weight and dynamic response.
Inert gas for safe infusion bags
The production and filling of single and multi-chamber infusion bags requires maximum process safety. To reliably protect the bags from degenerating, they are flooded with the inert gas nitrogen when they are being filled. During this process, the flow rate must be adjustable to prevent spraying during injection. This is where the VEMD comes into play, since it reliably meets the high requirements for reproducibility.
Build-up welding with argon is faster and more diverse
With build-up welding, the material is applied in layers. This is done with the help of a laser that applies layer after layer of metal or plastic powder and fuses them. These additively manufactured, complex components can be produced as a single, cohesive piece. The shape no longer matters.
The powder is transported using argon. When dosing the powder in the laser, a corresponding amount of argon is therefore added. The VEMD is suitable for this task when it is recalibrated for use with argon. By choosing this solution, which is significantly more cost-effective than conventional mass flow controllers, enormous cost savings can be achieved per machine.
Air and ice – the right blend for greater enjoyment
The VEMD can also be used for applications in the food processing industry, e.g. in compact ice cream machines. The amount of air mixed with the ice is critical for preventing ice crystals from forming.
The control of step-controlled needle valves has in some cases proven not to be consistent enough to ensure uniformly high product quality. The excellent ratio of high precision and low costs of the VEMD is impressive, since it ensures a high level of enjoyment for customers.
About the author
Dr. Stefan Bammesberger
Product Management LifeTech
Festo AG & Co. KG