MICROFICHE REFERENCE LIBFUUW - Cd3wd.com

58shaft), two other forms of these pumps can be utilized. The first iscommonly called a mine or sinking pump and is simply a compact, directactingpump which can be lowered into a narrow shaft along with steam orcompressed air hoses for power. The second alternative for deep wellpumping is to lower a bucket-piston with connecting rod to within NPSHRlimits of the water surface. The rod is connected to a prime mover at thewell surface which, due to the long rod length, operates at low speeds(40-65 stokes per minute--spm). These surface prime movers, often referredto as pump heads, are usually gas engines or electric motors, however,throughout the early 1900’s, steam pump heads were common (Greene, 1913).These bucket-pumps can be single-acting or can utilize double-actingcylinders as in Figure 3.14.Initial costs vary greatly on mechanically driven piston and plungerpumps, depending on size, availability, manufacturer, etc. Manufacturer’scatalogs must be consulted for exact prices, however, even the smallestlifter-driver units have “new” prices starting at over $200. Severalcompanies manufacture bucket-pump units similar to the one in Figure 3.14,which can be designed to use with several drivers, i.e. the connectingrod can be extended up to a windmill, or it can be attached via a cam gearto a small engine or motor, or a handle can be attached for manual use.However, in addition to these commercial bucket-pump units, lesssophisticated units are easily constructed by local craftsmen in manydeveloping countries. The principles of local manufacture and simpleconstruction have lead several international assistance organizations todevelop designs for lift pumps which can readily be utilized in developingcountries.