Abstract
Proportioning pumps can be used as flow-rate controllers to good advantage, if the stroke and speed are known and controllable, and if the volume discharged by the pump is equal to its displacement. The discharge may be greater or less than the displacement, depending upon the relationships between such parameters as rate of plunger displacement, friction losses in the suction-side and discharge-side piping, masses of liquor in both the suction and discharge lines which must be accelerated and decelerated at each stroke, elevations of supply and discharge tanks, and so forth. The relationships between these factors, as they affect pump volumetric performance, are eveloped on a theoretical basis, and simple tests are devised which will enable an engineer to predetermine whether or not a proposed installation will be satisfactory, and which indicate what changes must be made to correct an unsatisfactory design. The conclusion is drawn that the range of conditions under which a proportioning pump will give satisfactory performance as a meter is considerably restricted so that a careful and thorough analysis of each proposed installation is essential.
