« ForrigeFortsett »
IV. Haldane gas-analysis apparatus -------
V. Copper oxide apparatus for complete analysis of gases-----
saturation of carbon monoxide in blood, and the analysis of
tures and pressures----
Figure 4. Curves of equal relative humidity for varying temperatures
and volumes of water carried
SAMPLING AND EXAMINATION OF MINE GASES AND
By GEORGE A. BURRELL and FRANK M. SEIBERT; revised by
G. W. JONES
FOREWORD In this bulletin, the style of Bulletin 42 has been closely followed. Much of the material is reprinted on the following pages in its original form, and changes have been made only where manifestly necessary. Laboratory methods have been brought up to date. Some types of apparatus described in Bulletin 42 have now become obsolete ånd newer designs are described instead. The authors hope that this bulletin will be of as much service as was Bulletin 42.
ACKNOWLEDGMENTS Revision has necessitated the inclusion of data that have been published within the last few years. Proper credit is always given the authors of such material by references to the original articles. The reviewer especially acknowledges his use of information taken from papers prepared by R. R. Sayers, W. P. Yant, G. G. Oberfell, M. C. Teague, I. W. Robertson, F. N. Neumeister, W. C. Harpster, W. L. Parker, S. H. Katz, J. D. Davis, and A. C. Fieldner.
INTRODUCTION TO BULLETIN 42 The Bureau of Mines, as part of its designated duty of investigating the causes of mine accidents, is conducting at its experiment station in Pittsburgh, Pa., a study of mine gases. Some of the work already done in connection with this study is outlined below.
A large number of samples of mine gas have been collected under normal conditions in returns and in splits, and at other points in the ventilating current; also at the face, in the goave or gob, in unventilated places, and wherever the air was still. Samples have also been obtained under abnormal conditions, as after explosions and while mine fires were in progress, or from sealed areas behind stoppings and dams where the air had been stagnant for some time.
1 Burrell, G. A., Robertson, I. W., and Oberfell, G. G., Black damp in mines : Bull. 105, Bureau of Mines, 1916, 92 pp.
Chemical changes in the composition of mine atmospheres during mine fires have been studied, and conditions peculiar to certain mines have been investigated.
The effect of a change in atmospheric pressure on the escape of gas (methane) in coal mines has been studied. Explosives have been fired in both coal and metal mines, and samples of resulting gases have been collected to ascertain the degree to which these vitiate the air. A series of samples in mines where gasoline locomotives were being used has been examined in order to ascertain the degree to which the exhaust gases from such locomotives foul the air.3 Experiments have also been made in regard to the relative effect of carbon monoxide upon men and small animals,4 the effect of oxygen deficiency on men and animals, and the flammable limits of combustible gases found normally in mines and during and after mine fires. 6
These investigations have necessitated making numerous gas analyses, many requiring special methods and designs of apparatus. The methods described herein are largely an outgrowth of the above investigations and are now used as standard methods at the gas laboratory of the Pittsburgh station of the Bureau of Mines.
COLLECTION OF SAMPLES OF MINE GASES
SAMPLING BY THE VACUUM METHOD In nearly all mines where there is enough air movement—say, a velocity of at least 100 feet per minute-samples of atmospheres are taken by the vacuum-bulb method. Glass bulbs of about 250-c. C. capacity (2 by 6 inches in size) are made at the Pittsburgh experiment station of the Bureau of Mines. As these bulbs are made they are evacuated as completely as possible by a high-vacuum pump, and the long capillary neck is sealed with a flame during the final stage of evacuation. Then the bulbs are labeled and numbered and are ready
2 Burrell, G. A., and Seibert, F. M., Gas analysis as an aid in fighting mine fires : Tech. Paper 13, Bureau of Mines, 1912, 16 pp.
: Hood, 0. P., and Kudlich, R. H., Gasoline mine locomotives in relation to safety and health : Bull. 74, Bureau of Mines, 1915, 84 pp.
4 Burrell, G. A., Seibert, F. M., and Robertson, 1. W., Relative effects of carbon monoxide on small animals : Tech. Paper 62, Bureau of Mines, 1914, 23 pp.
5 Burrell, G. A., and Oberfell, G. G., Effects of oxygen deficiency on small animals and on men : Tech. Paper 122,, Bureau of Mines, 1915, 12 pp.
6 Burrell, G. A., and Seibert, F. M., The inflammable gases in mine air: Tech. Paper 39, Bureau of Mines, 1913, 24 pp. Burrell, G. A., and Oberfell, G. G., The limits of inflammability of mixtures of methane and air: Tech. Paper 119, Bureau of Mines, 1915, 30 pp. ; Explosibility of gases from mine fires: Tech. Paper 134, Bureau of Mines, 1916, 31 pp. ; The explosibility of acetylene : Tech. Paper 112, Bureau of Mines, 1915, 15 pp. Burrell, G. A., and Robertson, I. W., Effects of temperature and pressure on the explosibility of methane-air mixtures: Tech, Paper 121, Bureau of Mines, 1916, 14 pp. Burrell, G. A., and Gauger, A. W., Limits of complete inflammability of mixtures of mine gases and of industrial gases with air: Tech. Paper 150, Bureau of Mines, 1917, 13 pp.