Abstract: A diaphragm assembly for the demand regulator of a breathing apparatus utilizes a diaphragm that gradually flattens down against a conical platform so as to reduce the effective sensing area. Advantageously the diaphragm is used in conjunction with an aspirator opening adjusted for maximum aspiration effect at low flow rates. At increased flow rates the reduced sensing area compensates for increased aspiration, insuring stable operation. The diaphragm periphery cooperates with the conical platform outer edge to serve as the regulator exhaust valve.

Abstract: A scuba regulator second stage utilizes pneumatic amplification to achieve very low inhalation effort. The regulator includes (a) a main flow valve consisting of a poppet moveable within a valve housing inside the regulator body, (b) a pilot valve mounted within and carried by the main valve poppet, and (c) a pressure sensing diaphragm linked to the pilot valve.During inhalation, the diaphragm and linkage open the pilot valve to admit gas at supply pressure into a space, between the poppet and a closed end of the housing. This gas displaces the poppet, thereby opening the main flow valve and supplying gas to the diver. Pneumatic amplification is achieved. The poppet displacement tends to close the pilot valve, so that the poppet-opening force is reduced. This feedback effect results in substantially linear relationship between inhalation demand and the amount of breathable gas supplied to the diver.

Abstract: In a scuba or other breathing apparatus, the demand regulator includes a diaphragm connected by a linkage to a valve that supplies breathable gas to the user in response to inhalation demand, as sensed by the diaphragm. The linkage includes a diaphragm-connected lever situated between a ball restrained for axial movement and a fixed member having a spherical surface facing the ball. The lever pivots on the spherical surface to cause sensitive displacement of the ball and hence actuation of the valve.

Abstract: A diaphragm assembly for the demand regulator of a breathing apparatus utilizes a diaphragm that gradually flattens down against a conical platform so as to reduce the effective sensing area. Advantageously the diaphragm is used in conjunction with an aspirator opening adjusted for maximum aspiration effect at low flow rates. At increased flow rates the reduced sensing area compensates for increased aspiration, insuring stable operation. The diaphragm periphery cooperates with the conical platform outer edge to serve as the regulator exhaust valve.