Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.
Original content can be found on Parker’s website and was written by Dan Ewing, senior chemical engineer, Parker Hannifin O-Ring & Engineered Seals Division.
In the rush to massively increase the number of medical ventilators available to treat patients with severe cases of Covid-19, using the correct seal materials for those ventilators should never take a back seat to expediency.
Medical ventilators are mechanical devices that essentially breathe for a patient with damaged lungs. They force air into the lungs and draw it out, augmenting or even replacing the natural functions provided by the movement of the diaphragm and the inflation/deflation of the lungs themselves. These devices can supply room air, pure oxygen, or nearly any ratio of the two to the patient, depending on health needs.
What makes a good seal selection in this environment?
First, seals within the device must be compatible with air and pure oxygen. They should not harden or crack, nor should they contain a significant amount of volatile matter that can evaporate out of the seal where it could be inhaled by the patient or potentially catch fire in a concentrated oxygen environment. Further, it should be assumed that any air that contacts the seals will likely end up in the patient’s lungs. As a result, it’s strongly recommended using seal materials that have passed USP <87> Class VI testing for any seals used in a medical ventilator.
Parker O-Ring & Engineered Seals Division has already helped several customers ramp up production of critical medical equipment with supplying the right materials and O-rings for the application.
These application requirements limit the recommended compounds to only a small handful.