Complex check valve seal designs by Minnesota Rubber and Plastics, Minneapolis, are being used in a topical oxygen device by GW Medical, Chadds Ford, PA. Topical oxygen therapy is used to treat patients with non-healing wounds such as burns, diabetic ulcers, pressure sores and post-op wounds. The device by GWR Medical is designed to provide an oxygen-enriched environment around the wound area for extended periods allowing the wound to heal. The device is designed in two versions, a boot and sacral model. The boot model fits around areas of the leg and arms while the sacral model fits around the body itself. When positioned properly, the device provides an airtight cavity of oxygen surrounding the wound.

Both the check valve and relief valve functions are controlled by the double silicone diaphragm in the middle of the assembly and the two mating outer components (polycarbonate), which hold and center the diaphragm.  The check valve stops the flow of oxygen out of the bag if the patient disconnects from the oxygen source. The relief valve maintains the inflation pressure inside the bag so that the bag is inflated and maintains its optimal pressure setting. Combining these two functions into a single double diaphragm reduced the part count, eliminated separate springs and seals, and simplified assembly.   

The three-piece assembly also creates a seal between the bag and check valve/relief valve assembly when snapped together thereby eliminating the need for adhesive or welding operations.

Minnesota Rubber and Plastics provided product design and materials engineering in the development and manufacture of this check valve/relief valve assembly.