Normal breathing under water

Title

Creator

Manila Bulletin

Language

English

Year

1965

Rights

In Copyright - Educational Use Permitted

Fulltext

NORMAL BREATHING UNDER WATER A wisp of synthetic mem brane, only a thousandth of an inch thick, may hold the answer to a simple system for supplying submarines with air drawn from the water around them, the purifica tion of air in space capsules or moon stations, and a means of providing cheap, reliable oxygen supplies for patients in hospitals or at home. The secret lies in a sili cone film that is thinner, and therefore more permeable than any silicone membrane ever before reported. Even though this membrane is completely free of holes, it permits the passage of liquids or gases. The method of pro ducing the membrane was discovered by Dr. Walter L. Robb of General Electric company research laboratory. Possible applications are be ing studied at the GE’s ad vanced technology laborato ries and elsewhere. Membranes have been made from a variety of ma terials, one of the most use ful is a special type of sili cone rubber in the develop ment of which GE research played a major role during World War II. The mem brane is 30 times as perme able as" the rubber in auto mobile tires would be at equal thickness and 1,000 times as permeable as the plastic films used for wrap ping foods. Since different gases pass through the membrane at different rates it is called “selective.” The ability of the membrane to “select” those gases which will pass through most easily could be applied to space capsule. An opening covering with such a membrane would al low unwanted water vapor and carbon dioxide to escape easily into the vacuum of space, while vital oxygen was held in, because the first two October 1965 59 gases pass through much more quickly than oxygen. In fact, since water vapor passes through 60 times as fast as oxygen, the mem branes might be used on earth as devices for dehumi difying air. Oxygen, on the other hand, passes through such a mem brane over twice as fast as nitrogen, which makes up 80 per cent of the air we breath. As a result, if ordinary air is brought into contact with one side of a membrane, while the other side of the membrane is maintained at a lower pressure, the gas passing through the mem brane will be rich in oxygen. If the low-pressure side of the membrane is maintained at 1/15 of atmospheric pressure, for example, the air passing through will contain appro ximately 35 per cent oxygen, instead of the usual 21 per cent. The 35 per cent figure is close to that found in hos pital oxygen tents and infant incubators. In industry, enriched air is used in a variety of pro cesses, where the membrane system could reduce costs. Helium could also be “fil tered” out of air or natural gas. In such cases, other types of polymers would be used, rather than silicone rubber, since various poly mers differ in the rate which they allow different gases to pass through. U n d erwater applications would depend upon the fact that sea water is essentially saturated with air to a depth of many hundreds of feet. A membrane with sea water flowing past on one side and with pressure below one at mosphere on the other side would extract air, while re sisting the passage of water under tremendous pressure. — Manila Bulletin. 60 Panorama

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