First stage scuba regulator

Abstract

A first stage scuba regulator wherein the intermediate pressure to the second stage regulator increases as tank supply pressure decreases, thus solving the problem of the sensitive second stage at the start of the dive and decreasing the cracking efforts and improving low pressure flow rates at lower tank pressures. The design employed in the present invention for creating an intermediate pressure inversion relies on undersizing the critical balancing shaft of the piston where high pressure air entering from the tank is neutralized between the high pressure O-ring and plastic high pressure seat. By reducing the effective area of a shaft under the O-ring, but in front of the sharp end of the piston, an imbalance is created. This imbalance is in the forward or closing direction of the piston shaft. This extra force decreases the load requirement of the spring and lowers the intermediate pressure at the high supply pressure. As the supply pressure decreases, the closing imbalance decreases and the intermediate pressure begins to rise. This is due to the area force diameter of the smaller unbalanced side of the piston. In addition to providing an effective inversion of the variation in intermediate pressure with supply pressure, the present invention also provides a novel factory adjustment capability so that small manufacturing variances can be accommodated externally of the regulator after it is assembled, without requiring the use of shims or other internal mechanisms which would require disassembly and reassembly.