Method of and means for operating breathing apparatus

June 11, 1935.

A. HLOCH

2,004,243

METHOD OF AND MEANS FOR OPERATING BREATHING APPARATUS

Filed Jan. 11, 1929

Sheets-Sheet 1

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June 11, 1935. a. hloch 2,004,243

METHOD OF AND MEANS FOR OPERATING BREATHING APPARATUS Filed Jan. 11, 1929 2 Sheets-Sheet 2

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Patented June 11, 1935

2,004,243

UNITED STATES PATENT OFFICE

2,004,243

METHOD OF AND MEANS FOR OPERATING BREATHING APPARATUS

Albert Hloch, Lichterfelde, near Berlin, Germany, assignor, by mesne assignments, to I. G. Farbenindustrie Aktiengesellschaft, Frankfort-onthe-Main, Germany, a corporation of Germany

Application January 11, 1929, Serial No. 331,315 In Germany January 17, 1928

Claims.

My invention relates to methods of generating oxygen in accordance with requirements, more particularly for breathing and inhaling purposes.

The principal object of the invention is to pro0 duce oxygen from chemicals in a constant flow during a given period as is in particular necessary in breathing and inhaling apparatus.

It has already been proposed to produce oxygen in a more or less constant flow from chemicals 10 evolving oxygen under the influence of water supplied in the form of drops. The function of such apparatus is of course not independent of the position of the apparatus, nor is the production of oxygen in fact constant. In another type of 35 apparatus the moisture contained in the exhaled air is used for decomposing the chemicals. In this case the development of oxygen is dependent on the breathing intensity in such manner that a period of slow breathing will be followed by a 20 period of slow development of oxygen, when possibly a much higher breathing activity will have taken place, so that the production will be insufficient. By this reason apparatus of this type have been provided with an auxiliary water 25 supply.

It has also been known to produce oxygen from a body composed of solid chemicals evolving oxygen in the absence of water under the influence of heat. This method, however, necessitated stor30 age of the oxygen, as the chemical body was consumed almost at once, and this storage necessarily had to take place under a certain pressure. The evolution of oxygen therefore was not a constant one, but often more or less explosive.

Now according to the invention the chemical mass is so composed and shaped that the evolution of oxygen takes place, after initiation, in a reaction which proceeds continuously and uni• formly through the whole chemical mass in such 40 a way that during the whole period of use the oxygen is evolved in constant quantity per unit time in accordance with the requirements of the apparatus. Therefore no storage is necessary and no pressure is produced. Moreover, when em45 ploying the method in breathing apparatus, the functioning is just as independent of breathing as in the old method of supplying oxygen from high pressure steel bottles, but without needing , a reducing valve.

The composition, the shape (more particularly the cross-section) and the compression of the chemical body are to be chosen according to desire or need. By adding oxidable substances to the mixture of chemicals I may increase the evolv55 able amount of heat if required as, for instance, (Cl. 23—6) if a loss of heat by radiation or convection is to be avoided or balanced. On the other hand I add, if required, a suitable catalyst for the purpose of reducing the decomposing temperature of the chemical substances and thereby decreasing 5 the drop of temperature outwards, but just as well I may add any suitable catalysts for speeding the development of oxygen, since in both cases the object is to maintain an uninterrupted decomposing process. 10

Apparently the heat evolved by the decomposition and the heat required for maintaining the progressive decomposing process, must balance whence in case of low temperatures of the outer air a wrapping or covering of insulating material, ₁₅such as an asbestos cylinder, an air jacket or the like, may be employed for ensuring a constant heat balance.

The accompanying drawings show for purpose of exemplification, several embodiments of the 20 invention.

In the drawings:—

Fig. 1 is a view in vertical axial section of a cylindrical chemical body accommodated in a sheath or casing constituting a receptacle for the 25 evolved oxygen;

Fig. 2 is a view in top plan thereof;

Fig. 3 is a view in vertical axial section of a modified chemical body;

Fig. 4 is a view in top plan thereof; 30

Fig. 5 is a lateral elevational view of a portable mine breathing apparatus with closed respiration circuit, the lateral protective sheet or cover being removed; and

Fig. 6 is a frontal elevation thereof, partly in 35 section and with a protective cover removed.

Parts which are repeated in the several figures bear the same reference characters in each case.

Referring to Figs. 1 and 2 the chemical body I is of cylindrical shape and both the peripheral 40 surface and the end surfaces thereof are coated with a heat-protective covering 2 made of asbestos. As regards the substances whereof the chemical body is composed, they comprise one, two or several chemical compounds such as perborates, 45 perchlorates, chlorates, permanganates, bichromates, plumbates and peroxides of the alkali and alkali-earth metals, capable of evolving oxygen upon heating.

In manufacturing a chemical body of the stated 50 kind I subject the said chemical compounds, in moist condition to a high pressure in a suitable mold so that the compressed material when released of pressure and dried will possess a sufficient cohesion or physical consistence to with- 55

2,004,243 stand impact and friction incidental to manipulation. For the purpose of increasing the physical consistence thereof, however, I sometimes add and mix with the chemical compounds a suitable substance which does not and cannot deliver any injurious gases when heated by the heat produced by the oxygen evolving process during the operation of the apparatus. Preferably I use for this purpose asbestos fibres which, due to the high heat capacity and the low heat conductivity thereof, at the same time contribute to ensure a slow but steady progress of the reaction or decomposing process.

If a catalyzer is employed, the asbestos fibre may be impregnated with the same. In order to obtain the oxygen in moist condition for inhaling purposes, I may add to the substances forming the chemical body certain admixtures such as hydroxide of calcium, containing chemically bound water which will be set free by the reaction.

Moreover this setting free of water is an endothermic process absorbing a part of the heat produced by the exothermic oxygen evolving reaction, thereby controlling the progress of the reaction in such a manner that a constant flow of oxygen is secured.

In Fig. 1 the chemical body consists of a main portion ia and an additional portion lb composed to bring about a . quicker initial decomposition combined with or resulting in a rapid production of heat and a correspondingly rapid storing up of the necessary amount of heat indispensably required for an uninterrupted continuation of the decomposing process. The amount of the thus stored heat depends upon the volume or size of the additional portion lb and the particular composition thereof, and these two factors in turn on the cross-sectional area of the chemical body and the calculated or presumed efficiency thereof in a unit of time.

The components of the chemical body are mixed with sufficient water and compressed in steel molds under a high pressure, to form rods of preferably circular section. By the decomposition sufficient heat will be developed to ensure and maintain the temperature required for the gradual decomposition of the oxygen evolving substances up to final consumption thereof.

The portion lb will after initiation develop a larger oxygen stream during a few, for instance 2 to 3 minutes, in order to have the apparatus including the breathing bag rapidly filled up with oxygen, before the slow development, in accordance with the need for respiration, takes place.

It will be seen in Fig. 1 that the top end of the portion lb is recessed at 3 and that the bottom of the recess 3 is bored or otherwise excavated for the accommodation of an initiating primer 4 duly protected from accidental ignition during transportation or manipulation of the apparatus. In some cases I also add to the chemical compounds constituting the body I, oxidable substances such as powdered aluminum and the like, or cellulose for the purpose of both reducing the compactness of the composition and thereby rendering the same more readily inflammable. The primer 4 is provided with a pin 5 having a head 6 projecting into the recess 3 and consisting of a combustible or ignitable material such as used for making the head of a match, or the like.

The chemical body I is encased in a cylindrical sheath or receptacle 8 with a cylindrical partition of wire gauze 7 inserted in the annular space between the inner wall of the receptacle and the body I. The ™>re gauze may consist of iron, aluminum or any other metal or alloy which under the action of oxygen will form a superficial oxydic layer acting to protect the metal from further oxidation or corrosion, while the receptacle 8 may be made of brass or preferably of 5 aluminum in order to reduce the weight thereof. The lid 9 of the receptacle is hinged to the latter by means of a link 10 and adapted to be locked in closed position by means of bolts 11 passing through peripheral bores of the lid and engaging 10 in corresponding threaded holes provided in an annular flange Ία of the receptacle 8, an annular downwardly projecting rib or ridge 9α of the lid engaging with a gasket 12 disposed on the top edge of the receptacle and consisting preferably 15 of a copper-coated asbestos ring, so that a per- . fectly tight seal will be attained. A similar annular ridge 9b of a shorter diameter is provided on the inner surface of the lid and adapted to engage with the top surface of the chemical body 20 when the lid is closed, in order to secure the former in position and to thereby prevent the primer from being accidentally ignited during the manipulation of the apparatus.

The centre of the lid is shaped to form an out- 25 wardly projecting boss 9c axially bored and threaded for the reception of the threaded portion 13α of a screw 13 provided at its outer end With a small hand wheel 14, while the inner end of the screw is fitted or integral with a disk 15. 30 Resiliently connected with the disk 15, preferably by means of a coiled spring 16, is a friction-disk 17 which truly projects into the recess 3 of the chemical body normally a certain distance apart from the ignition head 6 of the primer pin. The 35 lower surface of the depending disk 17 is serrated or knurled, so that when the screw 13 is screwed down by means of the handle 14 the knurled surface of the disk 17 will be caused to move into gripping coaction with the head 6 for the ignit- 40 ing purpose, the power of the spring 16 being such that, the friction-disk 17 first, that is immediately upon engagement with the head 6, will remain motionless due to friction, until the spring 16 is sufficiently stressed by the continued rota- 45 tion of the hand wheel 14 to overcome the frictional engagement, when the thus retarded disk 17 will suddenly fly forward under the action of the overstrained spring and cause the head 6 and the primer to be ignited. 50

The irrespirable gases evolved by the combustion of the head 6 are allowed to escape into the open air through bores 9e provided for the purpose in the lid 9, whereupon the screw or spindle 13 is to be turned in opposite direction so far 55 that or until a gasket 18 attached to the upper surface of the disk 15, engages with a cooperating circular ridge or rib 9d integral with the lid 9, so that the evolved oxygen will be prevented from escaping through the openings 9e or the 60 thread of the screw 13. In breathing apparatus for use in mines the lid 9 may be provided with a cap 73 of wire-gauze for the purpose of enclosing the openings 9e so as to prevent the danger of explosion. 65

The ignition of the head 6 causes the primer 4 to ignite and be consumed and evolve intensive heat so as to ignite the substance or portion lb of the chemical body I wherein the ignition still advances at a comparatively quick rate so that 70 the oxygen evolved thereby will be in excess of the calculated normal production, for the purpose of scavenging the apparatus and fill the same with oxygen, but the excessive production of oxygen ceases when the substance or portion lb 75

2,004,243 is completely consumed and the substance or portion la of the chemical body commences to evolve oxygen at a normal rate as required and calculated for a serviceable operation of the 5 apparatus.

The oxygen continuously delivered by the substance or portion la passes through the wire gauze 7 and escapes from the receptacle 8 through an outlet or duct 19 provided near or adjacent 10 to the bottom thereof and connected with a filtering vessel 20. Fitted in the vessel 20 are two perforated plates or disks 21 and 22, for instance - of wire gauze or perforated sheet metal, spaced apart to constitute a compartment for the pro15 vision of a filtering layer 23 of any suitable fibrous material, such as felt, adapted to separate out and retain from the oxygen gas solid particles such as coarse dust. Fixed to the inner side of the closing cap 24 of the vessel 20 is a 20 cylindrical frame or basket 25 which projects into the vessel so as to occupy the space above the upper disk 22 and which is enclosed in or covered with a closed filtering screen 26, such as cellulose paper or a ceramic material of fine 25 porosity for the retention of the finer dust particles which have not been intercepted by the coarse screen 23. The layer 23 may be impregnated with scents, medical drugs or chemical substances for the removal of chemical impuri30 ties from the oxygen gas flowing through the filtering chamber, but obviously a separate filtering device may be provided in the apparatus for such purposes.

The fibrous material 23 may be dispensed with 35 if the perforations in the plates 21, 22 are sufficiently narrow to retain the coarse impurities. Of course it willthen be advisable to provide the plate 22 with narrower perforations than the plate 21 and further filtering plates of stepped40 down width of perforations may be arranged therebetween.

The oxygen developed from the portion lb of the chemical body carries with it a considerable quantity of fine smoke which would rapidly clog 45 the fine filtering screen. But at the same time the oxygen is charged with a considerable quantity of moisture, consequently under the influence of the low temperature of the perforated plate or wire gauze 21 a film of water is de50 posited on the latter and this film will retain even very fine impurities, so that the fine screen will at first only have the object to retain those of the finest impurities which will not. have been retained by the coarse screen. The oxygen de55 veloping from the portion la of the chemical body does not carry with it smoke in considerable quantities, so that the retaining action of the coarse screen on fine impurities is no more necessary. At the same time this oxygen is less ₆0 charged with moisture, and as meanwhile the filter has been progressively heated the dust layer deposited on the coarse screen will dry and crumble away, so that an automatic cleaning of the 'filter will take place.

_C5 Rigidly connected or integral with the cap 24 is a central tubular extension 24α with a lateral branch 24b for the attachment of a pressure gauge 75, while the free end of the tube 24α is provided with means for detachable connection 70 with a pipe 27 adapted to be connected with a rescue apparatus, inhaling apparatus, a mine breathing apparatus and the like, a retarding disk 74 with a narrow central hole 74α, being inserted into the lower end of the pipe 27 to 75 serve, in connection with the pressure gauge 75, the purpose of insuring a required pressure in the apparatus and indicating the same to the wearer so that the means comprising the disk 74 and the gauge 75 constitutes a kind of a safety device for the wearer, particularly in case of a 5 mine breathing apparatus to ascertain at any time whether a certain pressure indicating the normal progress of the decomposition of the chemical body prevails or whether the latter is going to be consumed and consequently the io pressure commences to drop. If the apparatus is supplied with a plurality of oxygen evolving devices or chemical bodies disposed and adapted to be ignited in succession, the wearer will thus be able and prepared to ascertain the proper 15 time for igniting the next chemical body or for returning to safety if a further chemical body is not available in the apparatus. Obviously the gauge may also be adjusted for indicating the amount of gas which has flown through the sys- 20 tern prior to the moment of indication. Instead of the gauge or alternatively in combination therewith any suitable acoustic or other alarm device of known construction and adjusted to be operated by drop of pressure may be employed 25 with advantage in many cases. In a similar manner also the second or next following chemical body may be automatically ignited by suitable means to be provided and adjusted to startignition upon a certain predetermined drop of 30 pressure.

The apparatus illustrated in Figs. 5 and 6 belongs to that class of breathing devices which supplies an oxygen atmosphere to the wearer so that he can enter with safety a mine or any 35 other room containing irrespirable gases. The oxygen evolving receptacle 8, the filtering vessel 20 and a caustic potash cartridge 61 for the absorption of. exhaled carbonic acid are accommodated in a box 59, and a second box 60 en- 40 closes a respiration bag 62 made of a flexible air-tight material such as rubber or rubbercloth. The receptacle 8 communicates with the filtering vessel 20 through a pipe 63 and a pipe 6S is provided to interconnect the vessel 20 and 45 the casing of a non-return valve 65 disposed intermediate between the caustic potash cartridge 61 and the exhaling tube 66 of the mask 67, while the inhaling tube 68 is equipped at its lower end with a non-return valve 69 adjacent to the head 50 70 to which the respiration bag 62 is attached and which is connected with the caustic potash cartridge by means of a pipe 71, a safety valve 72 being provided in the lateral connecting nipple of the head 70. 55

The construction and operation of this mine breathing apparatus is known in general regards but for the oxygen evolving chemical body or cartridge and the filtering means associated therewith in substitution for the usual steel bot- go tie with condensed, oxygen. Due to the respiration of the wearer the inhaled and exhaled air or oxygen is constrained to circulate, owing to the cooperation of the two non-return valves 65 and 69, from the mask 67 through the several parts G5 66, 65, 61, 71, 70, 69, 68 back to the mask 67 and \ so on, while the bag 62 serves the balancing purpose. The reaction or evolution of oxygen in the receptacle 8 is to be initiated with the aid of the small hand-wheel 14 when subsequently a 70 certain calculated quantity of oxygen per unit of time will be continuously supplied by the receptacle 8 or the chemical body therein and caused to flow through the parts 63, 20 and 64 into the circuit at such a point thereof that no 75

2,004,243 oxygen can enter the inhaling branch 68 of the circuit without having travelled before through the caustic potash cartridge.

The oxygen evolving material forming the 5 chemical body may be given an admixture of substances which will evolve, during the decomposition of the chemical, carbonic acid or any other sanative gas such as chlorine, which will be useful in rescue cases on accoiint of its facul10 ty of irritating the respiratory centre. As regards the generation of carbonic acid in the apparatus, those carbonates or bicarbonates of the alkali metals, alkali-earth metals or heavy metals may be used for the purpose which when heated 15 to a temperature of 800° C. or less, will partially or totally deliver the carbonic acid contained therein, but even certain organic substances may be added which under the existing conditions will combine with the nascent oxygen to form 20 carbonic acid.

If an apparatus is intended to be used continuously for a comparatively long period of time as, for instance, a mine breathing apparatus, and a single chemical body only is pro25 vided for the purpose, I may use a double or twin-body with an insulating partition between the two components, as shown in Figs. 3 and 4, so that the reaction setting in at one end of the one component will proceed to first consume 30 this one component and then go oyer to the other component and consume the same in reverse direction. The twin-body i shown in Figs. 3 and 4 consists of a cylindrical structure or rod formed by compressing the oxygen evolving ma35 terial la in a suitable mold, and provided with a diametrical longitudinal slit 79 which extends from the top to nearly the bottom end face for the reception of an insulating partition 80, preferably a compressed asbestos sheet.

4θ The portion lb of the chemical body composed to evolve an excess of heat for the ignition of the underlying portion of material la, is provided at the top end of the one component only and recessed at 103 as hereinbefore described with 45 reference to Fig. 1. The primer 4 with the ignition pin 5 and head 6 is similar to that shown in Fig. 1. The adjacent top end of the other component is reduced to a diametrical plane somewhat below the bottom surface of the recess 50 103 and protected from premature ignition by the covering 2. When the chemical body shown in Fig. 3 is ignited'by means of the inflammable head 6, as hereinbefore described, the oxygen evolving reaction or decomposition will slowly 55 proceed and gradually consume the one component in downward direction and then catch the other component and consume the same slowly and gradually in upward direction. Obviously the chemical body or cartridge may be composed _co of more than two components in juxtaposition with insulating partitions therebetween and with their contiguous extremities alternately connected.