The Petroleum Diver's Mask

Triple XXX Enterprises of Norwich England developed the PDM (Petroleum Diver's Mask) for the commercial diving industry, primarily the offshore oil industry .
The PDM provides breathing by both demand and free-flow. In the demand regulator an oral-nasal mask is provided to prevent the build up of carbon dioxide. There are two exhausts provided to ensure adequate ventilation in the mask , one being in the second stage and the other in the base of the mask. Water accidentally entering the mask can be forced out through this exhaust.

Two way communication is provided as standard with the PDM. The microphone is inserted in the oral-nasal mask and the two speakers are located on either side of the head within the wet hood.

The PDM may be used with Scuba cylinders, surface supplied air or mixed gas. Both the demand and free-flow masks have a bail-out facility as standard. A non-return valve is fitted on the main hose connection as standard. The hood is detachable and easily replaceable in the field.

The mask shell is made from G1 specification Bronze. This material was chosen for its strength and resistance to corrosion from salt water.. The mask shell has a very low profile due to its design. The helmet is designed with balance in mind. The shell is coated with a black stove enamel finish. The face port is made from 3 mm acrylic sheet. The face seal is made from open cell foam with a thin closed cell neoprene cover attached at one side.. The assembly is then sealed within a wet hood. Two pockets also made of closed cell neoprene are sealed within the hood having their openings to the front of the mask. Into these pockets are fitted the speakers.
The hood is fitted over the mask shell. A split hood band is placed over the hood and shell sealing lip and is securely tightened.
The spider band is stamped from natural rubber and tension is acquired by adjusting the prongs into an appropriate hole on the spider. Correct adjustment will mean a comfortable fit. The two lower bands may be removed to facilitate the removal of the band mask.

All metal parts are machined from brass stock and the hose connector swivels through 180 degrees.. The emergency gas valve 4 allows for connection directly to the mask. When the valve is turned on this puts pressure on the valve. Should the main supply fail the hand wheel is turned on thereby allowing the breathing gas to flow into the mask as before. The free flow valve 3 permits a controlled volume of air to flow into the mask and the hand wheel is so designed to allow the diver with cold hands to operate it with ease.. The exit point of the free flow gas is by means of a double locked nut which also serves to scatter the gas.

The mask serial number and identification number is stamped on the front of the mask body.

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• Last update: 15th April 2008