Rebreather system

Abstract

A semi-closed rebreather that uses a “normal open” type of solenoid valve to control the flow of replenishment gas supplied to the rebreather circuit by at least one replenishment gas cylinder. In the absence of energy, the rebreather system takes the open condition, thereby allowing a replenishment gas flow with a maximum flow rate predetermined during the initial design or adjustment step.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a semi-closed circuit rebreather system.BACKGROUND OF THE INVENTION[0002]A semi-closed circuit rebreather is a device that allows the diver's exhaled gas to be reused, by filtering the carbon dioxide content and replacing the oxygen metabolized during breathing.[0003]The air around us consists of about 21% oxygen, 78% nitrogen and 1% other gases such as helium, argon and others. To survive, humans must breathe a gas with minimum oxygen content. Not all the breathed oxygen is metabolized and thus consumed during breathing, but that does not mean that you could just breathe a gas containing the amount of oxygen that is then actually metabolized.[0004]Under normal conditions, for example, we inhale 21% oxygen and exhale about 17% (which is why, for example, mouth to mouth breathing can provide the oxygen needed to maintain or restore the basal level of oxygen in the body of a person undergoing cardiopulmonary reanimation), na...

AI Technical Summary

Benefits of technology

The invention provides a system for rebreathers that ensures safety in case of malfunctions or power loss. It uses a rebreather type system that automatically takes a safe condition in case of such failures. The system also regulates the oxygen fraction in the breathing gas mixture by controlling the flow rate of the replenishment gas and the opening time of the supplying means. This allows for optimal use of the gas and ensures user's survival conditions during surfacing. The invention also provides a rebreather system with a second cylinder for decompression, which is optimized for long decompression times. In this system, a first cylinder containing replenishment gas is disconnected from the circuit and a second cylinder with high oxygen concentration is connected to the circuit, so that the decompression process is effectively carried out with gases having high oxygen concentration.

Problems solved by technology

But if the oxygen content of the inhaled gas drops below 18%, symptoms such as headaches and other discomforts begin to occur and, below 16%, even more problems begin to occur.

A further lowering of the value leads, among other things, to sleepiness, which is followed by death without the person really realizing it.

Hypoxia can obviously be lethal, but also hyperoxia can lead to very serious consequences.

This type leads to an extreme simplification of the system due to various reasons that are not the object of this patent, but has one drawback: if 4 units of oxygen metabolized in a respiratory cycle have to be replenished then in so doing 6 units of nitrogen are necessarily added as well.

This excess volume of gas must be disposed of in the environment because otherwise the counterlung volume increases excessively thereby pushing the diver to the sea surface.

This leakage has two obvious drawbacks: the gas lost contains oxygen too, so the system efficiency is lower than that of the closed circuit, and moreover, by using a mixture of oxygen and nitrogen to replenish oxygen, with respect to the gas mixture in the cylinder a fraction of oxygen lower than the starting one will be always obtained.

However, in order to cover the oxygen demand in emergency conditions, the flow of replenishment gas is still required to be very high and, as a result, the system efficiency is low in terms of breathable gas consumption.

Systems of this type are known at the state of the art, but they are designed so that in the absence of power (electricity in the form of batteries powering the various circuits and valves) the control system stops and the oxygen consumed is no longer replenished.

In these systems, however, in case of absence of power and / or electronics malfunction, the current rebreather systems stop the supply of replenishment gas and thus generate a dangerous condition for the user.

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