320 



THE INDIA RUBBER WORLD 



[March 1. L91S. 



i return to the feature of economy, the German physicist 

 gnized that all of the oxygen taken into the lungs was 

 nol absorbed into the system and that a very appreciable 

 percentage <>t it passed out again al the time of exhaling. His 

 aim was to regenerate this oxygen and at the same time to 

 make up the deficiency by drawing on a supply of compressed 

 oxygen held in a compact metallic flask. To this end, he 

 found that granules oi can-tie potash and caustic soda had 

 the powei "i absorbing the carbon dioxide and water vapors 

 coming from the lungs while leaving the life-saving oxygen 

 contained in the exhaled breath to pass on to be used over. 

 Just enough new oxygen from the reserve tank was then 

 required to furnish the needful 

 normal called for by nature and 

 demanded by the amount of work 

 done bj the w carer of the rescue 

 apparatus at the time. 





Ojc/cjen ^ 

 i Showing Now mm. Smoke Helmet Works. 



'lie i impanying illustration, with the following descrip- 

 tion, "ill enable a layman to understand the regenerative 

 i Ins ingenious and up-to-date life-saving equipment 

 for service anywhere in any irrespirable atmosphere. When 

 the apparatus is donned, the lungs and respiratory organs 

 of the wearer are completely shut off from the external air, 

 and form, as it were, a portion of the apparatus. In this 

 enclosed system, into which air is no longer admitted from 

 the outside, there are only two forces in operation for actuat- 

 ing the air. namely, the lungs of the wearer and the injector 

 C, of the outfit. The injector is operated by the power of 

 the compressed oxygen in the tank. Between these two 

 forces are interposed the breathing bags L. and L„ as reser- 

 3 and at the same time acting as compensating buffers 

 between the intermittent respiration of the human lungs and 

 the continuously circulating air of the apparatus. The lungs 

 actuate the air in order to nourish the body with oxygen 

 ami to expel tin carbon dioxide, while the apparatus sets the 

 air in motion for the purpose of eliminating the carbon 

 dioxide with which it is contaminated and also to enrich it 

 once more with fresh oxygen. 



The exhaled air passes through the exhaust valve V 2 , then 

 into the air bag I. : . and from there it is drawn in a uniform 

 manner. It next flows through the connecting conduit to 

 the potash cartridge. P, wdiere the carbon dioxide expelled 

 from the lungs is absorbed and thus rendered harmless. At 

 the same time, the cartridge becomes heated by the warm breath 

 which reaches it. The air, now free from carbon dioxide, next 

 enters the cooler, K, where a portion of the heat it has absorbed 

 is dissipated by radiation, whence it passes on to the injector, 

 C. Here it is revivified with oxygen supplied from the oxygen 

 cylinder at the rate of two litres (120 cubic inches) per minute. 

 The air mixture is now once more ready to be inhaled, and flows 

 through the second circulating pipe into the inhaling bag. L,. 

 whence it is inhaled through the inhaling valve, V,. The cycle 

 of operations then begins afresh 



The capacity of the apparatus is such that it is able to purify 



about 3,000 litres (JO? cubic feet) of air per hour, to supph 

 about 120 litres (4j£ cubic feet) of oxygen and absorb 50 litres 

 ( 1 >_| cubic feet) of carbon dioxide. Double these quantities 

 are dealt with in two hours. The potash cartridges and ox>gcn 

 cylinder, which form the ammunition of the rescue weapon, are 

 calculated to serve onlj lor a certain tune, and at the end of 

 that period they must be replaced. The oxygen cylinders can be 

 recharged, but the spent potash cartridges are as worthless as 

 those discharged from a gun, because of the chemical changes 

 that have taken place in the soda and potash which have 

 absorbed moisture and carbon dioxide. 



The so-called cartridges are a mechanical counterpart oi 

 the lungs, inasmuch as they are provided with a large surfaci 

 for absorption. In order to insure the taking up of the carbon 

 dioxide and vapor, a series of 20 flat metal trays is arranged 

 upon which there are layers of caustic potash and caustic soda, 

 in granular form, inside of the metallic casing. These trays, 

 with their openings, are so placed that the air in following through 

 pursues a zig-zag course, and thus is brought intimately and 

 continuously in contact with the cleansing chemicals. In the 

 latest form of the rescue equipment, a spent cartridge can be 

 withdrawn and a fresh one placed in the circuit in a few seconds, 

 and as we have said, provision is made for a continuous working 

 period of two hours for the rescuer. 



Now the man interested in rubber naturally wants to know- 

 how extensively that material enters into the vital get-up of this 

 extremely ingenious apparatus. To begin with, the two air bags 

 containing, respectively, the respirable and the exhaled air, are 

 made of thick rubber of the finest sort, because their elasticity is 

 an important characteristic, and are covered with leather pads to 

 shield them from harm in service. The helmet would fail of its 

 purpose if it did not fit snugly about the face of the wearer so as 

 to shut out foul gases seeking admission back of the ears and 

 likewise the escape of the vitalizing air. Accordingly, the appara- 

 tus has been made so that it will adapt itself to every shape of 

 face. If the face be long or broad, large or small, the inflatable 

 rubber pad just inside of the headpiece conforms to the shapi 

 the wearer. This pneumatic pad 

 is in effect much like an oval air 

 cushion, and the degree of its in- 

 flation is regulated by the rescue 

 worker by simply operating a 

 rubber bulb pump. The face pad 

 is made of the best Para rubber 

 and in one piece, and the little 

 hand pump is of the same fine 

 material. Indeed, all of the rub- 

 ber parts are of selected quality, 

 because otherwise they would not 

 measure up to their work in 

 some atmospheres charged with 

 certain chemical fumes. 



But this is not the end of india 

 rubber's share in the construe- I NFLATAB le Rubber Face Pad 

 tion of this life-saving appara- AND R UBBER Bulb Pump 

 tus. The various flexible tubes, F0R Filling it with 



all gaskets or washers, ear pieces, \| R 



mouthpieces, telephone insula- 

 tion, etc., are of rubber. Another form of the so-called rescue 

 equipment, not intended for so prolonged a service, does away 

 with the helmet and the wearer draws his air directly into his 

 mouth by a simple tube and his eyes are protected by goggles 

 secured in a fume-tight setting of rubber which also pinches bis 

 nose and closes his nostrils, so that he can not unwittingly or in 

 a moment of excitement draw the foul air into his lungs. The 

 particular virtue of this latter form is its greater compactness and 

 the added facility with which it can be carried by a fireman and 

 donned at the critical moment. Of course, it does not afford tin- 

 same general protection to the head of the wearer nor can it 



