Low Profile Auto Dump Valve Operation

The volume of air in the dry suit is controlled by means of a rotating cap. Turning the cap clockwise increases the spring load acting on the valve seat and allows a larger volume of air to be maintained in the dry suit. Anti-clockwise rotation of the cap reduces the spring load, allowing air to escape and so hold a smaller volume of air. The rotating cap also features a ratchet mechanism, to prevent accidental adjustment of the dump valve.

As the diver ascends, the air in the dry-suit expands, increasing the diver's buoyancy. The auto-dump valve senses the increased pressure in the dry-suit, which lifts the valve seat against the spring, allowing air to vent. This venting action maintains the volume of air in the dry-suit and allows a controlled ascent by the diver. If, at any time during the dive, it is felt that there is too much air in the dry-suit, the cap can be pressed manually to over-ride the valves settings and vent excess air.

If the cap is pressed with insufficient dry-suit pressure a secondary non return valve is fitted to prevent the ingress of water into the dry-suit.

Selection of under clothing is important to allow escaping gas to vent through the valve, however the back nut is designed to prevent under clothing from blocking the escaping gas.