Underwater heat sink

Claim 2

A cryogenic underwater breathing apparatus of the type wherein liquified gas is allowed to vaporize to augment a breathing gas mixture, said apparatus comprising: a first tank including insulated wall portions in part defining first and second adjacent chambers, said first tank also including heat exchange wall means between said first and second chambers and means for circulating breathing gas through said first chamber; a body of first liquified gas in said first chamber substantially at a predetermined low temperature; a body of second liquified gas in said second chamber also substantially at said predetermined low temperature; means defining a third chamber; adsorption material disposed in said third chamber and adapted to reduce pressure therein below a predetermined equilibrium pressure for said second liquified gas at said predetermined temperatures; a pressure responsive regulating valve; duct means connecting said pressure responsive regulating valve between said second and third chambers; and said pressure responsive regulating valve being responsive only to gas pressure in said second chamber and operative to vent gas from said second chamber to said third chamber, so as to maintain said equilibrium pressure and said predetermined low temperature.

Claim 3

A cryogenic underwater breathing apparatus as defined in claim 1, and wherein said regulating valve comprises: a valve body having a flow passage connected at one end to said second chamber and at its other end to said third chamber, said body defining fourth and fifth chambers on opposite sides of said flow passage and communicating only with said one end thereof; a valve member disposed between said ends of said flow passage and movable between open and closed positions with respect to said flow passage; spring means disposed in one of said fourth and fifth chambers and operative to urge said valve member toward one of said positions; and pressure responsive actuating means disposed in the other of said fourth and fifth chambers and operative to urge said valve member toward the other of said positions.

Claim 4

A cryogenic underwater breathing apparatus as defined in claim 2, and wherein: said first and second liquified gases each comprise liquid oxygen, and said adsorption material comprises a molecular sieve material.

Claim 5

A cryogenic underwater breathing apparatus of the type wherein liquified gas is allowed to vaporize to augment a breathing gas mixture, said apparatus comprising: a first tank including insulated outer walls, said tank including first and second chambers separated by heat exchanging wall means, and additional wall means for guiding circulating breathing gas through said first chamber; a body of liquified gas in said first chamber at a predetermined low temperature; a body of second liquified gas in said second chamber also substantially at said predetermined low temperature; a second tank defining a third chamber; adsorption material disposed in said third chamber and adapted to adsorb vapor of said second liquified gas and to reduce pressure in said third chamber below a predetermined equilibrium pressure for said second liquified gas at said predetermined temperature; a pressure regulating valve; duct means connecting said pressure regulating valve between said second and third chambers; said pressure regulating valve comprising a valve body having a flow passage connected at one end thereof by said duct means to said second chamber and at the other end thereof to said third chamber, said body defining fourth and fifth chambers on opposite sides of said flow passage and communicating only with said one end thereof, a valve member disposed between said ends of said flow passage and movable between open and closed positions with respect to said flow passage, spring means disposed in said fourth chamber and operative to urge said valve member toward one of said positions, an expansible and contractable bellows disposed in said fifth chamber and operative upon predetermined pressure change in said second chambers to move said valve member towaRd the other of said positions, whereby said pressure regulating valve is ambient pressure independent and operative to vent gas from said second chamber to said third chamber so as to maintain said equilibrium pressure and said predetermined low temperature therein.

Claim 6

A cryogenic underwater breathing apparatus of the type wherein liquified gas is allowed to vaporize to augment a breathing gas mixture, said apparatus comprising: a first tank including insulated outer walls, said tank including first and second chambers separated by heat exchanging wall means, and additional wall means for guiding circulating breathing gas through said first chamber; a body of liquified gas in said first chamber at a predetermined low temperature; a body of second liquified gas in said second chamber also substantially at said predetermined low temperature; a second tank defining a third chamber; adsorption material disposed in said third chamber and adapted to adsorb vapor of said second liquified gas and to reduce pressure in said third chamber below a predetermined equilibrium pressure for said second liquified gas at said predetermined temperature; a pressure regulating valve; duct means connecting said pressure regulating valve between said second and third chambers; said pressure regulating valve comprising a valve body having a flow passage connected at one end thereof by said duct means to said second chamber and at the other end thereof to said third chamber, said body defining fourth and fifth chambers on opposite sides of said flow passage and communicating only with said one end thereof, a valve member disposed between said ends of said flow passage and movable between open and closed positions with respect to said flow passage, spring means disposed in said fourth chamber and operative to urge said valve member toward one of said positions, an expansible and contractable bellows disposed in said fifth chamber and operative upon predetermined pressure change in said second chambers to move said valve member towaRd the other of said positions, whereby said pressure regulating valve is ambient pressure independent and operative to vent gas from said second chamber to said third chamber so as to maintain said equilibrium pressure and said predetermined low temperature therein.