==========+======================================+================== | Size of Pipes for | Approximate | Short Lengths To be | Space Occupied | increased as Length Increases | Feet and Inches +-------+---------+---------+----------+--------+--------- Diameter | | | | | | of Steam | Steam | Exhaust | Suction | Delivery | | Cylinders | Pipe | Pipe | Pipe | Pipe | Length | Width ----------+-------+---------+---------+----------+--------+------ 3 | 3/8 | 1/2 | 1-1/4 | 1 | 2 9 | 1 0 3 | 3/8 | 1/2 | 1-1/4 | 1 | 2 9 | 1 1 4-1/2 | 1/2 | 3/4 | 2 | 1-1/2 | 2 10 | 1 1 | | | | | | 4-1/2 | 1/2 | 3/4 | 2 | 1-1/2 | 2 10 | 1 1 5-1/4 | 3/4 | 1-1/4 | 1-1/2 | 1 | 3 1 | 1 4 5-1/4 | 3/4 | 1-1/4 | 1-1/2 | 1 | 3 1 | 1 4 | | | | | | 6 | 1 | 1-1/4 | 1-1/2 | 1 | 3 5 | 1 5 6 | 1 | 1-1/4 | 1-1/2 | 1 | 3 5 | 1 5 6 | 1 | 1-1/4 | 1-1/2 | 1 | 3 5 | 1 5 | | | | | | 7-1/2 | 1-1/2 | 2 | 4 | 3 | 3 6 | 1 6 6 | 1 | 1-1/4 | 1-1/2 | 1 | 3 5 | 1 5 7-1/2 | 1-1/2 | 2 | 4 | 3 | 3 6 | 1 9 | | | | | | 7-1/2 | 1-1/2 | 2 | 4 | 3 | 3 7 | 1 9 9 | 1-1/2 | 2 | 4 | 3 | 3 8 | 1 11 9 | 1-1/2 | 2 | 4 | 3 | 3 9 | 1 11 ==========+=======+=========+=========+==========+========+====== [Illustration: FIG. 50.--Raising water by means of compressed air.] Figure 49 shows a cut of a small duplex Worthington pump which operates by steam, not requiring any intermediate engine. To show the variety of pumps made and the way in which the proportions vary with the capacity of the pumps, the preceding table is given of pumps of small capacity designed to work with low steam pressure. _Air lifts for water._ Compressed air is also a source of power for raising water from a deep well; but it is neither economical in first cost of apparatus nor in operation. The principle is shown by the diagram of Fig. 23, and explains without words how air pressure may be carried down into the well through one pipe and thereby force the water of the well up into another pipe far above its natural level. The machinery needed involves an engine or motor and an air compressor, the latter taking the place of the ordinary pump. It has the single advantage that it avoids the maintenance of valves and similar deep-well machinery at a great distance below the ground, the air pump not requiring any mechanism in the well.