Controlling the flow rate of inert gases in medical equipment

Parker Hannifin has unveiled its VSO LowPro miniature proportional valve for controlling the flow rate of inert gases in medical equipment.

Just 16mm wide by 14mm tall, the valve addresses a key requirement for small portable devices where installation space is at a premium. This ensures that medical devices can benefit from a miniature valve that doesn’t compromise on performance due to size.

Typical applications for the new valve include pressure control, volumetric flow control and pulse dose control in devices such as portable oxygen concentrators, ventilators and patient monitors.

Another key requirement for the medical device industry is reliability of operation, which ultimately can be the difference between life and death. With the VSO LowPro reliability is assured with operations up to 25 million cycles, thus delivering that much needed peace of mind. By their very nature, portable medical devices also need to consume low power and feature high performance, this valve series delivers in these two vital areas. The VSO LowPro miniature proportional valve offers typical flow rates of up to 45SLPM with a maximum of 2W power at room temperature. What’s more with an orifice of up to 2.03mm and a weight of 12g, the VSO LowPro can perform the function of valves three times its size without sacrificing power.

It’s also important for OEMs to keep a tight control on costs to be competitive.  This new valve features a low profile design which simplifies mounting and eliminates cartridge configurations that require complex and expensive machining, thus keeping a tight control on cost. Compliant with REACH, RoHS, CE, ISO 10993 and ISO 145001, three voltage models are available, 5, 12 and 24VDC. The two-way, normally closed VSO LowPro valve is designed to handle air, oxygen or any non-reactive, non-condensing gases. Very low power, typically 1W, enables portable capability and allows designers to reduce the size of the power supply or battery.

The VSO LowPro valve can be controlled by either voltage or current; however, it is recommended that current control be employed to ensure the most repeatable valve flow performance. For PWM (pulse width modulation) control, the signal applied to the valve should have a frequency of between 5-12kHz, with the optimum frequency dependent on the application.

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