Evaluation of Northill 'Air-Lung'Regulator with Modified Diaphragm and Plugged Reserve Device,

摘要

Following reported high breathing resistance in production models of the Northill 'Air Lung'demand regulator,units were tested at EDU (Experimental Diving Unit) and found not to meet acceptance criteria. The manufacturer confirmed this and traced the defect to a faulty diaphragm mold. Modified regulators were submitted with an improved diaphragm and the reserve feature eliminated. Extensive mechanical respirator and subjective trapeze and pool tests revealed fully acceptable resistance characteristics. However, a noise-vibration condition exists at shallow depths during forced inhalation and on this basis the regulator is not accepted. A design defect in the new model, Northill 'ON-OFF'mouthpiece is also noted. (Author)