A device for heat exchange for use with underwater diving equipment including a pressurized gas source is disclosed. The heat exchange device includes a manifold and a heat sink. The manifold distributes gas supplied from the pressurized gas source to breathing equipment. The heat sink is for warming up the gas before the gas is distributed to the breathing equipment using heat exchange with ambient water surrounding the heat sink. The manifold and the heat sink are connected such that the gas warmed up by the heat sink returns to the manifold before being distributed to the breathing equipment. The returning warm gas may warm up the manifold and the cold gas entering the manifold.

A regulator first stage for two-stage underwater breathing apparatuses includes a reduction chamber communicating with a high-pressure gas supply through a balance valve, which is influenced by the pressure of the external environment by a balance diaphragm that, by way of a suitable actuator, acts on the valve. The reduction chamber includes one or more medium pressure outlets, having axes parallel to the operating axis of the balance valve. In one configuration, one or more medium pressure outlets are also provided having axes orthogonal to the operating axis of the valve.

A second stage diving regulator with separated stages that allows changing a position of connection of a LP hose for low/medium pressure supplied from a first stage of the regulator, characterized in that around connected bodies there is a rotating ring with a valve seat and a valve terminated with a threat to which a low/medium pressure LP coming from the first stage of the machine is connected horizontally. The rotation of the rotary ring is ensured at least in the range of 180 degrees from the starting position, through all the intermediate angles downwards towards the cylinder, up to a horizontal position opposite to the starting position, the side of the body.

Methods and systems to provide breathing air to underwater divers in response to the divers' respiration at pressures less than 25 psi above atmospheric pressure during inspiration while delivering no or minimal air during exhalation, by controlling the actions of a pump during the time course of breathing. Methods and systems that sense a diver's need for breathing air, determine inhalation demand or exhalation state, and control the operation of a pump which delivers breathing gas to the diver via a tube. An integrated system for the same which incorporates at least an energy source, pump, air tube, breathing aperture, sensor, and logic processor is disclosed.

Noise reduction in face masks and helmets reduces ear damage and improves communication by reducing noise in demand regulators with air diffuser perforated plates, screens or open cell foam and by providing muffling chambers. Insertable earmuffs are slid into voids formed in interior padding. Oral-nasal masks are isolated from helmet padding. Various layered helmets shells and padding reduce internal noise.

An apparatus for adjusting the partial pressure of gaseous mixtures comprises a housing and piston. The housing defines a chamber coupled to an oxygen metering orifice, diluent metering orifice, vent port and gas outlet. The oxygen metering orifice provides oxygen to the chamber and the diluent metering orifice provides diluent gas to the chamber. The piston is movably positioned in the chamber and includes first and second sealing devices. The chamber is sectioned into a mixing chamber, a diluent chamber and a reference chamber located between the mixing chamber and diluent chamber. The diluent chamber receives a diluent gas referenced at ambient pressure and the reference chamber is charged with a gas having a reference pressure. The piston changes positions within the chamber depending on a force balance created by a pressure differential between the reference pressure and ambient pressure.

Methods and systems to provide breathing air to underwater divers in response to the divers' respiration at pressures less than 25 psi above atmospheric pressure during inspiration while delivering no or minimal air during exhalation, by controlling the actions of a pump during the time course of breathing. Methods and systems that sense a diver's need for breathing air, determine inhalation demand or exhalation state, and control the operation of a pump which delivers breathing gas to the diver via a tube. An integrated system for the same which incorporates at least an energy source (26), pump (28), air tube (30), breathing aperture (10), sensor (20), and logic processor (24) is disclosed.

A first stage pressure regulator is provided. A valve body has an inlet and an outlet that define a pressure chamber therebetween. The valve body defines a pressure compensation chamber having an opening fluidly communicating the pressure compensation chamber with the surrounding water. The first stage pressure regulator comprises an inlet tubular union removably received into the inlet. A removable high pressure orifice body defines an orifice therethrough. The orifice body is carried by the valve body proximate the inlet. A valve seat is within the valve body.

A regulator first stage for two-stage underwater breathing apparatuses includes a reduction chamber communicating with a high-pressure gas supply through a balance valve, which is influenced by the pressure of the external environment by a balance diaphragm that, by way of a suitable actuator, acts on the valve. The reduction chamber includes one or more medium pressure outlets, having axes parallel to the operating axis of the balance valve. In one configuration, one or more medium pressure outlets are also provided having axes orthogonal to the operating axis of the valve.

A pressure reducing second stage for underwater use includes a case provided with a breathing gas inlet, with an inhalation/exhalation port and with an exhaled gas exhaust outlet with a non-return valve, the gas inhalation/exhalation port being connected to a mouthpiece tube, the breathing gas inlet in the case being connected to a breathing gas pressure reducing device provided with a hollow cylindrical element or pipe, which has a breathing gas inlet port communicating with a gas supply conduit through a valve which is interposed between the supply conduit and the mouthpiece tube, the case being provided with a pressure sensitive means device for controlling the opening/closure of the valve. The breathing gas inlet in the case is provided in its lower portion and the hollow cylindrical element is connected to the inlet on the case such that its axis is substantially vertical, when used in the upright position.