Precision engineering for continuous patient warming
The Mistral-Air® Warming unit for blankets is a medical care product for effective and continuous patient warming. The Mistral-Air® is used in hospitals and medical clinics. PCV Group helped design and develop the MA 1200, a new and improved version of the Mistral-Air® that was introduced onto the European market at the end of 2017. The American launch took place mid 2017.
The Mistral-Air® is a simple to operate precision product for forced air warming. It keeps patients warm before, during and after surgery by distributing warm air with an almost constant temperature to keep a patient warm at 37 degrees. The Mistral-Air® is a popular fixture in many operating theaters.
For the development of the next generation The 37Company wanted to make some significant and innovative changes to the air blower. A number of critical to quality parameters were defined. The challenge the newly formed project team was looking to solve, was developing a next generation Mistral-Air® more silent than its predecessor and also with a significantly smaller fan with a larger air flow. Medical products also have to comply with numerous health regulations and licensing. In accordance with these rules, The 37Company wanted the Mistral-Air to have an inbuilt high-efficiency particulate air filter (HEPA). Combining multidisciplinary strengths within our team, PCV Group succeeded in meeting all criteria and requirements.
The varied product criteria and the technological challenge to be able to heat up air and maintain an almost constant temperature of a desired setpoint at end of hose, demand a multidisciplinary approach. The 37Company initially asked PCV Group to join their project team for a review of the first prototype and to advise them on how to meet all functional requirements and on the design of plastics for the casings and the design for assembly.
Starting with ‘our understanding of your problem’ our team of engineers laid bare a number of flaws in the pre development stage that would lead to problems if the prototype were to be taken into production. On the basis of our advice The 37Company decided to backtrack in the development process. They asked PCV Group to collaborate with them. We expanded the project team by calling on the expertise of one of our network partners: 3T. A company highly specialised in electronics and embedded systems.
The approach (2)
An critical element for success for projects like the Mistral-Air® is being able to not only bring together different talents within one team, but to use them to their full potential. PCV Group is a T-shaped organisation avoiding the wellknown pitfall of tackling a technological challenge solely from an engineering point of view. We actively invest in the combination of technical expertise with our communicative and project management skills. This enables our team members to work in close conjunction with each client creating the best solutions. Not only in a technical sense but also from the viewpoint of the users.
The initial prototype put too much emphasis on the look and feel of the product, and too little on the key criteria for use by hospital staff. Revising the design the PCV Group engineers followed a structured and systematic approach tackling a whole list of challenges. We’ve listed some of the main ones:
- Guaranteeing a constant temperature. The heated up air has to travel approximately two meters through a hose that’s attached to a surgical blanket. The air flow from the Mistra-Air® can be set at different temperatures, the mechanism measuring and in all circumstances ensuring that the forced air warming is never too hot or too cold. Adding to our calculations the fact that there is not always the time to spread out the hose in a perfect manner, we developed a printed circuit board with multiple sensors that measure the temperature of the air at different positions within the airflow. A smart algorithm system programmes the heater to automatically adjust, guaranteeing that the warm air at the end of hose never varies more than two degrees from the set temperature.
- Noise reduction. There was a challenge to break a record, because the predecessor of Mistral-Air® is already a relatively silent machine. The 37Company wanted to score points with this criteria while enlarging the air flow at the same time. A bigger air flow would automatically result in more noise. We tackled this effectively by applying precision engineering to improve the design of the fan. We tested various geometric lay-outs for a more compact design with a higher performance. Our material technology experts developed a rubber suspension mechanism for the fan, reducing the ventilator noise and vibrations and at the same time protecting the fan from everyday wear and tear.
- Superior sealing technology. Due to safety and hygiene regulations rigorous sealing requirements have to be met by manufacturers of medical equipment. Bearing this in mind, we had to come up with solutions for long lasting seals that wouldn’t obstruct the larger air flow and the suction of air via de HEPA-filter. Extreme endurance testing proved a neoprene rubber foam to be the best sealing material, maximising performance and able to withstand forces of up to 40 g (gravity acceleration) during transport.
PCV Group created a smart, silent and very durable solution for a medical apparatus that is simple to use and can be easily hung on a wall or mounted on a bed or a trolley. The Mistral-Air® was introduced at the European Medica Trade Fair in Dusseldorf from 13-16 November 2017. It has been enthousiastically received by representatives from the hospital and healthcare sectors.