Protective breathing aid device for diving or other operation under pressure
First Claim
1. Protective breathing aid device suitable for operation under an overpressure during both inhalation and exhalation phases, comprising an exhaling duct, a C02 -absorber, an equalization gas-containing chamber of variable volume having a movable wall and an inhaling duct, connected in sequence to provide a gas circulating path from said exhaling duct through said C02 -absorber and said chamber of variable volume to said inhaling duct, means for subjecting said chamber of variable volume to a force tending to reduce the volume of said chamber and of a magnitude for producing a sufficient pressure rise in said chamber for establishment of a desired overpressure of gas in said circulation path, a compressed gas supply reservoir of gas supplying oxygen for breathing and means including at least one duct line for leading gas from said supply reservoir to said inhaling duct, said means for subjecting said chamber to said force comprising:
- a cylinder-and-piston unit (13, 26, 40, 45,
61) including a cylinder and a piston therein, means for continuously supplying gas from said compressed gas supply reservoir to said cylinder during both inhalation and exhalation phases and mechanical means for enabling said piston to exert force continuously against said movable wall of said variable volume chamber and thereby to produce a continuous desired overpressure in said chamber.
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Accused Products
Abstract
A protective exhaling device of the circulating path type with exhaling protection, with its exhaling duct connected, in the circulating path through a CO2 absorber and a gas volume equalizing chamber containing a variable volume of gas, to an inhaling duct to which there is connected a reservoir of compressed gas supplying oxygen for breathing, has a cylinder and piston unit connected to the pressure bottle pressure or to an intermediate regulator pressure for pneumatically producing a force applied to the variable volume chamber. That assures that the force determining the overpressure level is always exerted at the same magnitude independently of the amplitude of the content of the equalizing chamber of variable volume. There is an automatic switchover from overpressure operation to normal underpressure operation in the case of a major leakage. For this purpose the cylinder and piston unit is provided with an outlet valve that opens when the piston goes beyond a predetermined stroke position, so that the overpressure diminishes through the piston and at the same time the supply of pressurized gas is blocked. Thus, in the case of major leakage there is no risk that the compressed gas supply will empty quickly without the user of the apparatus noticing it. After elimination of the leak overpressure can be reinstated manually or automatically. The equipment is suitable both for diving and for compressed air breathing protection equipment generally.
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Citations
12 Claims
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1. Protective breathing aid device suitable for operation under an overpressure during both inhalation and exhalation phases, comprising an exhaling duct, a C02 -absorber, an equalization gas-containing chamber of variable volume having a movable wall and an inhaling duct, connected in sequence to provide a gas circulating path from said exhaling duct through said C02 -absorber and said chamber of variable volume to said inhaling duct, means for subjecting said chamber of variable volume to a force tending to reduce the volume of said chamber and of a magnitude for producing a sufficient pressure rise in said chamber for establishment of a desired overpressure of gas in said circulation path, a compressed gas supply reservoir of gas supplying oxygen for breathing and means including at least one duct line for leading gas from said supply reservoir to said inhaling duct, said means for subjecting said chamber to said force comprising:
a cylinder-and-piston unit (13, 26, 40, 45,
61) including a cylinder and a piston therein, means for continuously supplying gas from said compressed gas supply reservoir to said cylinder during both inhalation and exhalation phases and mechanical means for enabling said piston to exert force continuously against said movable wall of said variable volume chamber and thereby to produce a continuous desired overpressure in said chamber.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. Protective breathing aid device of the compressed air type for operation under an overpressure during both inhalation and exhalation phases having an exhaling duct, a C02 -absorber, an inhaling duct and a bellows chamber having a movable wall (8) connected together so as to provide a gas circulation path leading from said exhaling duct, passing through said C02 -abosorber and then through said bellows chamber, to said inhaling duct, a source of compressed air, valve means responsive to movement of said movable wall for connecting said source to said gas circulation path and means actuated by a said movable wall under collapsing movement of said bellows chamber for operating said valve means for admission of compressed air to said circulating path, said device incorporating the improvement comprising:
a cylinder-and-piston unit (13, 41, 42, 61, . . . ) having a piston and a cylinder in which said piston is displaceable, means for continuously supplying compressed air from said source to said cylinder during both inhalation and exhalation phases, said piston being mechanically connected to and thereby bearing against said movable wall for subjecting said movable wall to a pressure from said source in a sense tending to move said movable wall in the direction for opening said valve means for admitting compressed air to said circulation path, and thereby providing a continuous desired overpressure in said path. - View Dependent Claims (12)
Specification