Compressed Air Work And Diving 1909

TESTING PUMPS. 37 compare the calculated air delivery witli that shown by the meter. Another way, and one for which the necessary gear will be more generally likely to be available, is to pump up into a receiver of known capacity. The pressure is obtained by compressing the pipe as with the clry gas meter' and the number of revolutions required to raise the pressure in the receiver to the gauge pressure on the pump is compared with the calculated number. Still another way would be to use two receivers con- nectecl together, and pump into one until the required pressure is obtained and then open the valve communicat- ing with the other and fill that, the number of revolutions being counted from the time the valve is opened. The valve must be opened in such a way as to maintain the pressure in the first receiver at the pressure for which the test is being made. TABLE X. Deplh. Cubic Feet of Free Air per Minute. Cubic Feet of Cylinder Capacity per Minute. Work in Com- pressing + Friction in foot- Ibs. per Minute. Fathoms. Feet. Efficiency = 75 per cent, at 198 ft. Efficiency = 50 per cent, at 193 ft. 0 0 1-5 1-5 1-5 5 4 33 3-0 3 2 3 3 5,500 li 66 4'5 5-0 5-4 13,000 16i 99 6-0 7-0 8'0 22,000 22 132 7'5 9'0 11-3 32,000 27 4 165 9-0 11-5 15’5 43,000 33 19S 10-5 14-0 21-0 55,000 38!, 231 12-0 17-0 29-0 66,000