Water Lifted By Compressed Air
For Municipal, Manufacturing, Irrigation or Other Water Supply

Fahrenheit may be employed, without attaining a mean cylinder tem- perature destructive to lubricants. The possibilities of expansion with such temperatures are not yet fully realized. Reheating, of course, removes all difficulties from freezing at exhaust, by raising the terminal temperature. But even where there is no reheating, proper precautions will prevent all trouble on this score. The use of after-coolers at the compressor, the provision of ample receiver capacity, the proper grading of transmission lines, with a small receiver at the lowest point from which accumulated moisture may be drawn through a draincock—these safeguards remove all moisture from the compressed air, and when there is no water there can be no freezing. There are some makeshifts for preventing freezing, such as lubri- cation with glycerine or the injection of a small water jet into air cylinder or exhaust port. But these are essentially makeshifts and should receive no consideration in a properly planned plant. In Conclusion. In conclusion be it said that the subject of pumping with com- pressed air is a very broad one, requiring the combination of the best engineering skill with sound practical experience. The pages pre- ceding have shown some of its possibilities and made clear the fact that extreme economy need not be neglected. Water can be pumped by compressed air with good results and high economy, and this in places where steam is forbidden and electricity, even at its best, would be very much at a disadvantage. The rules on page 94 are designed to be of assistance to engineers or others figuring on operating pumping plants by compressed air. They will aid in considering ordinary steam pumps. But in every case it is better that full information as to conditions be placed in the hands of the machine builder, who will then be able to properly advise. The Ingersoll-Sergeant Drill Company, therefore, subjoins the list following as a guide. Upon receipt of the information tabulated, they will advise in full. 1. Total vertical lift between water levels. 2. Total horizontal distance. 3. Rise and fall of water level. 4. All cylinder dimension of pumps now in use. 5. Diameter and length, and number of elbows, in water pipe lead- ing from pump to point of discharge. 6. Diameter, length and vertical height of suction pipe. 54