WO1986002063A1

WO1986002063A1 - Process for the production of oxygen by a portable apparatus, particularly for human respiration and apparatus to carry out the process

Info

Publication number: WO1986002063A1
Application number: PCT/EP1985/000474
Authority: WO
Inventors: Mario Caprara
Original assignee: Mario Caprara
Priority date: 1984-09-28
Filing date: 1985-09-16
Publication date: 1986-04-10
Also published as: IT1214865B; EP0227672A1; AU4800685A; IT8484131A0

Abstract

The process for the production of oxygen through a portable apparatus foresees that a mixture of sodium percarbonate and sodium perborate in presence of a suitable catalyst and water is made to react inside a tight vessel (1) according to the reaction 2Na2CO3. 3H2O2+ NaBO2.H2O2$(1,8)$2Na2CO3+ NaBO2+ 4H2O + 2O2 and thus the gaseous oxygen and satured steam flow obtained from such a reaction is made pass through an heat exchanger (2) which cools and dehumidifies it.

Description

"PROCESS FOR THE PRODUCTION OF OXYGEN BY ^A PORTABLE APPARATUS, PARTICULARLY FOR HUMAN RESPIRATI^ON A^ND APPAR_ATUS TO CARRY OUT THE PROCESS"

The present invention relates to a process for the production of oxygen by a portable apparatus, particularly for human respiration and an apparatus to carry out the process. It is known that it is possible to obtain oxygen

for human respiration from the decomposition of sodium

percarbonate ( 2Na, CO .3H 0 ) according to the following reaction

2Na CO .3H 0 > 2Na CO + 1,50₂+ 3H 0

Such a decomposition is obtained in presence of a

catalyst, preferably MnO . In order to practically obtain

such a reaction the sodium percarbonate powder is poured into a vessel with water and subsequently the MnO. powder is poured starting the reaction. As this reaction is strongly exothermic, it releases oxygen at high temperature and changes part of the water into steam, providing a mixture of

oxygen/steam which cannoc be directly used for human

respiration due to its high temperature and its excessive

humidity content. Furthermore the high reaction rate is such

that the pressure inside the vessel quickly reaches high

values and makes it compulsory, for safety reasons, to build the vessel with suitable materials which, beside affecting

the production costs, make the whole set heavy in contrast with the requirements of an easy handling.

To reduce the decomposition reaction rate of sodium

percarbonate it has been proposed to use large quantities of

water and to add very slowly the catalyst Mn0₂ to this and

to the sodium percarbonate. This by the way is not

obtainable with portable apparatus and even less in the

particularly conditions, generally in emergency, in which these apparatus are utilized, conditions which obviously do not allow the dosage of the catalyst and/or the sodium percarbonate with the correct timing and precision.

Always with the aim of reducing the decomposition

reaction rate of sodium percarbonate, it has also been proposed to differ the dissolution of the catalyst

Mn0₂ into the water, and this can be done using solids

composed of Mn0₂ powder treated with a solution of

polyvinyl alcohol with differentiated concentration. The

obtained solids, generally "balls" shaped, are mixed at the

moment of use with the sodium percarbonate powder. The

addition of water causes a reaction which, thanks to the different solubility of the polyvinyl cover, gradually

liberates the Mn0₂ thus allowing a control of the reaction.

With this measure with 300 g of sodium percarbonate and 600 g of water a production of 1-1,5 litres of oxygen is obtainable for 20-30 minutes for a total of about 32 litres.

However this solution has not proved satysfactory

for the unavoidable formation, jointly with the oxygen

production, of steam in such a quantity which does not allow

the direct administration to patients, taking into account

amongst others the high temperature of the mixture oxygen/steam; it also has a certain cost due to the necessity of using Mn0_ previously treated with polyvinyl

alcohol.

An aim of the invention is to avoid such drawbacks

and to produce, in a simple and economical form, oxygen by a portable apparatus of extreme semplicity of use, immediatly

usable in whichever conditions, also in emergency.

An other aim of the invention is to realize a

portable apparatus which allows to produce oxygen directly

usable for human respiration.

These aims and others which will result from the following description are obtained, according to the invention, with a process for the production of oxygen by a portable apparatus, particularly for human respiration, characterized in that a mixture of sodium percarbonate and

sodium perborate, in presence of a suitable catalyst and

water, is made react within a tight vessel according to the reaction

2Na₂C0₃.3H₂0₂+ NaB0₂. H₂0., ——» 2Na₂C0₃+ NaB0₂+ 4H₂0 + 20₂ and then the obtained gaseous oxygen and satured steam flow is made pass through an heat exchanger which cools and

dehumidifies it.

Advantageously a mixture of sodium percarbonate and

sodium perborate can be used in a weight ratio of 1:1 - 1:2,

preferably of 1 :1 ,15.

Also advantageously a MnO catalyst or other metal

salts such a Fe, Cu, Pb, etc. can be used.

In order to carry out the process, the invention

foresees the use of an apparatus comprising a reactor

connected to an heat exchanger from which the supply tube

containing oxygen and steam departs in such conditions as to allow the direct utilization for human respiration.

Advantageously the heat exchanger can be provided

with a coil submerged into a refrigerant liquid and connected to. the reactor.

Advantageously the reactor and the heat exchanger

can be built separately but mounted on a unique base and can be tight closed by a unique lid.

The present invention is hereinafter further

clarified with reference to the enclosed drawings in which: Figure 1 schematically illustrates the principle on which

the process according to the invention is based,

Figure 2 shows in vertical-longitudinal section a portable

apparatus ^"according to the invention.

As it can be seen from the drawings the principle

on which the present invention is based is to allow, within

a portable apparatus, a decomposition reaction of a mixture

of sodium percarbonate (Na CO .1,5 H O ) and of sodium

perborate (NaBO . H O ) in presence of a suitable catalyst and water according to the reaction

2N2 CO, .3H,0 + NaBO...H O > 2Na CO + NaBO + 4H 0 +20

2 3 2 2 2 2 2 2 3 2 2 2

The water has the function of dissolving the components of the mixture and at the same time partially

absorbing the heat which develops from the strongly exothermic chemical reaction.

The weight ratio between the sodium percarbonate

and sodium perborate is between 1 :1 and 1:2, preferably

1 :1.15.

The catalyst is preferably of the MnO , but in its

place metal salts such as Fe, Cu, Pb, etc. could be advantageously used.

The sodium perborate which, as the sodium percarbonate, participates in the decomposition reaction has the essential function of reducing the decomposition

reaction of the sodium percarbonate, reaction that otherwise

would be too strong and would take place in a too short time

with respect to the period of oxygen utilization.

The oxygen and steam flow which originate from the

reaction are thence made pass through an heat exchanger 2 in which the cooling of the oxygen and the partial condensation

of the steam take place, in order that the flow coming out from the heat exchanger 2 has pressure, temperature and humidity characteristics suitable for the direct human

respiration.

In order to carry out the process the invention

foresees the use of a portable apparatus consisting of three

containers, one being the reactor 1 from one side, one being

the shell of the heat exchanger 2 on the other side and the

third, interposed between the first two, being an overflow

interspace 3. The three containers 1 , 2 and 3 even if they are physically separed between themselves are mounted on a

unique base 1 and can be closed by one single lid 6. The lid 6 is provided with a gasket 7 which completely seals the external perimeter of the three containers 1, 2, 3 beside sealing the internal wall between the heat exchanger 2 and

the overflow interspace 3. In parallel to the walls of the overflow interspace 3, in the lid 6 a baffle 8 is provided

extending itself inside the interspace 3 and forming,

jointly with the adjacent side wall of the reactor 1 , a

labyrinth 5. In the lower zone of the heat exchanger 2 a coil 10

is housed with an end section 11 extending upward to be connected with the overflow interspace 3 near the lid 6.

The other end section 12 of the coil 10 extends

along the bottom of the container 2 and it is provided at

its end with a suitable diffusor 13. At the section of the

lid 6 which closes the container 2 an outlet conduct 14 is

applied provided with a standard oxygen tube input

connection 4.

In order to carry out the process according to the

invention, water is poured into reactor 1 and heat exchanger

2. In the very moment of utilization firstly the catalyst and subsequently the sodium percarbonate and sodium perborate are poured into the reactor 1 and then the apparatus is closed with the lid 6. The mixture

decomposition gives start to the oxygen and steam generation which pass from reactor 1 through the labyrinth 5 into the

overflow interspace 3 and from here, through the conduct 11, to the coil 10. a

Thence through the diffusor 13 they bubble in the shell of the heat exchanger 2. In the coil 10 the oxygen and steam are cooled down and dehumidified and made available,

through the conduct-14 and the connector 4, to a cannula or to a mask (not shown in the drawings) in suitable conditions

for human respiration.

The mixture of the above mentioned chemical

compound gives way to an exothermic reaction which increases

the volume of said mixture from two to three times. In the event that the liquid obtained from the

reaction goes over the capacity of the reactor 1 for self-effect or due to improper shaking, oscillation, inclination of the reactor during the reaction, the overflow interspace 3 collects the exceeding liquid without allowing

the same to overflow along the conduct 11 in the coil 10.

During the reaction the maximum pressure value

inside the reactor 1 is of 0.12 atm. Possible higher pressure, caused by the improper utilization of water at

temperature higher than that allowed, which can give way to

violent reactions or caused by the involuntary occlusion of

the connector 4, are self-regulated by lid 6 which is of a

pre-programmed bending type.

In fact the longitudinal structure 9 and the material used for the construction of the lid 6 allow this

to bend in a pre-programmed way. The thickness and the

elasticity of the gasket 7 complete such an effect.

So it has been obtained that the lid 6 is

water-tight up to the internal pressure of 0.13 atm and that for higher pressure it discharges outside the exceeding

oxygen caused by said higher pressure, keeping at constant

values both the internal pressure as well has the oxygen

supply to the connector 4. The following example referred to the above described apparatus will further clarify the invention.

In the reactor 1 which has a capacity approximately of 1450 g, 400 cc of water at 20°C have been poured and

subsequently 4 g of MnO_, with the function of catalyst has

been poured into it. In the heat exchanger 2, 500 cc of

water still at the temperature of 20°C have been poured. The

exact quantity of water to be poured into the containers 1

and 2 is easily identified by the two level signs 16 and 17

marked outside of each side container.

A mixture of powder composed by 163 g of sodium

percarbonate and by 143 g of sodium perborate has been

poured into the reactor 1. Immediately after, the lid 6 has been applied which ermetically closes, through the snap to

clamps 18, the container 2 and only perimetrically the

containers 1 and 3.

The decomposition reaction of the mixture

immediately started which has so originated the- 5 substantially uniform generation of oxygen and steam. 32 liters of oxygen at a max. temperature of 68-70°C and a relative humidity of 100% have been totally obtained.

The gaseous flow of oxygen and steam has passed from the reactor 1 to the overflow interspace 3 through the o upper connection leak and the labyrinth 5 which has provided to a first crack-down of solid elements in suspension as

well as to a partial condensation of the steam. The eventual

solid elements and the condensation have been collected in

the lower zone of the overflow interspace 3. The gaseous

15 flow has thus passed, through the conduct 11 into the coil

10. Here it has cooled down reaching, through the

extreme-end 12, the diffusor 13 which has made it bubble into the refrigerant liquid. This operation has allowed the definitive washing of the gaseous flow eliminating even the

20 smallest solid parts possibly present and still in suspension and the reduction of oxygen alkalinity up to acceptable values for human respiration. At the end the gaseous flow, through the conduct 14 and the connector 4 .

comes out at an average temperature of 22°C and at a

relative humidity of 72%, that is in a suitable condition- for the human respiration.

This sperimental test has been carried out pouring as stated above, in the reactor 1 and in the heat exchanger

2 water at the same temperature (20°C) and obtaining at the outlet an oxygen flow of 1,6 litres per minute at a relative humidity of 72%. However these characteristics of the

produced oxygen flow can be varied, according to the user's

needs, with the simple variation of the temperature of the

water poured into the containers 1 and 2. As in fact it

results from the following table, when diminishing the water

temperature poured into the reactor 1 , the oxygen flow

diminishes and consequently the duration of the reaction in the reactor 1 increases. Beside the lowering of the water temperature inside the heat exchanger 2 also the relative humidity of the produced oxygen flow diminishes. If, for instance, instead of pouring into containers 1 and 2 water

at 20°C, water is poured at 30°C, for a duration of 15

minutes an average oxygen flow of 2.8 litres/minute with a

relative humidity of 78% is obtained. If the needs of the

user make compulsory both a precise value of oxygen flow as

well as its relevant humidity, it will be sufficient to pour AVERAGE SUPPLY TABLE IN LITERS/MINUTE - WATER TEMPERATURE

into the reactor 1 water at the corresponding temperature to

the requested oxygen flow (shown in the relevant table) and,

in the heat exchanger 2, water at the corresponding

temperature to the requested relative humidity ( shown in the

relevant table).

Claims

C L A I M S

1. A process for the production of oxygen by a

portable apparatus, particularly for human respiration, characterized in that water with a mixture of sodium percarbonate and sodium perborate in presence of a suitable

catalyst is made react within a tight vessel according to the reaction

2Na„C0„. 3H„0„+ NaBO„.H 0 > 2Na CO + NaBO + 4H 0 + 20„

2 3 2 2 2 2 2 2 3 2 2 2 and then the obtained gaseous oxygen and satured steam flow

is made pass through an heat exchanger (2) which cools and

dehumidifies it.

2. Process according to claim 1 characterized in that

a mixture of sodium percarbonate and sodium perborate in a

weight ratio of 1:1 - 1:2, preferably at 1 :1.15 is used.

3. Process according to claim 1 characterized in that

MnO is used as catalyst.

4. Process according to claim 1 characterized in that

metal salts such as Fe, Cu, Pb, etc. are used as catalysts.

5. An apparatus to carry out the process according to

claims 1 to 4 characterized in that it comprises a reactor

( 1 ) connected to an heat exchanger (2) from which the supply conduct (14) containing oxygen and steam departs in such

conditions to allow the direct utilization for human respiration.

6. Apparatus according to claim 5 characterized in that the heat exchanger (2) is provided with a coil (10)

submerged in a refrigerant liquid and connected to the

5 reaction ( 1 ).

7. Apparatus according to claim 4 characterized in

that between the reactor (1 ) and the heat exchanger (2) an

overflow interspace (3 ) is interplaced.

8. Apparatus according to claim 7 characterized in

o that the reactor ( 1 ), the heat exchanger ( 2) and the

overflow interspace ( 3 ) are built separately but are mounted

on a unique base (15) and are tight closed by a unique lid (6).

9. Apparatus according to claim 7 characterized in 5 that the coil (10) is provided, at the end not connected to the overflow interspace (3), with a diffusor (13) submerged

in the refrigerant liquid.

10. Apparatus according to claim 5 characterized in

that the oxygen and steam flow is made pass through the 0 labyrinth ( 5 ) consisting in a transversal baffle ( 8 )

integral with the lid ( 6 ) and extending in parallel to the

dividing wall between the reactor ( 1 ) and the overflow

interspace ( 3 ).

11. Apparatus according to claim 7 characterized in

that the lid (6) is of the preprogrammed flexibility type.

12. Apparatus according to claims 8 and 11

characterized in that the lid (6) is provided with a gasket

( 7 ) of sufficient thickness and elasticity such as to allow

the perfect seal up to a prefixed pressure.

13. Apparatus according to claim 5 characterized in

that to the supply conduct (14) a connector (4) for an oxygen standard tube input is applied.