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New Type of Centrifugual Pump Description of the Roturbo Design Which the Manistee Iron Works Co. Will Manufacture and successful devel- rotary machinery of modern HE : opment of the form of electric motors and steam turbines has reacted on the cen- trifugal pump and created a demand for a design to meet all pumping prob- efficiency, lems and the _ highest so HEAT) -~YOLUME justment to varying heads. Self-regu- lation when attempted,. should be se- cured with the highest average effi- ciency over a wide range of duty. Until about ten years ago it was gen- erally agreed that centrifugal pumps were only suitable for low lifts and POLAT. Fic. 1--CoMFARISON 9F POWER CurRvES. A--ORrDINARY TURBINE CENTRIFUGAL PUMP; B--Rers Rorurso CENTRIFUGAL PUMP avoiding gearing and reducing cost, weight and expense. Hitherto centri- fugal pumps have fallen short of the general requirements of many problems due to their tendency to wear and con- sequently loss of efficiency when dealing with gritty water, also because of the lack of self-regulation or automatic ad- 7 large volumes of water, such as oc- cur in irrigation, sewage, salvage work and for circulating water for condens- ers. The efforts of early designers that the centrifugal type should not be limited to a few of the pumping prob- lems of the world is shown by the pat- IRON WORKS CO. ents taken out in the attempt to over- come the well. known difficulties, and to make the centrifugal pump suitable for high lifts by using a number of im- pellers in series. No doubt the delayed development was largely due to the fact that to get the best results from a_ centrifugal pump, impellers should be of small diameter running at high speed, rather than of large diameters running at low speed, but until the advent of the electric motor: and steam turbine there was no means of driving centrifugal pumps at the necessary speed except through belting or gearing with their inseparable difficulties and losses in transmission, which neutralized the ad- vantages aimed at in the pumps. With the introduction of electric mo- tors and steam turbines high efficien- cies became possible and for high. lifts" the old arrangement of impellers in ser- ies was revised and the centrifugal pump became a strong competitor of the plunger pump for conditions which used to be looked upon as only suit- able for reciprocating pumps. Perhaps the defect which has been the most difficult to overcome and which has decided the buyer in many cases against this type of pump, has been the fact that it would only work at its best at the exact head for which it was designed, the reason of this being that the blades of the impeller were shaped so as to pass a certain amount of water with the minimum a Fic. 2--Stock or Rotrurso PUMP Fic. 3--STEAM-DRIVEN Roturso Pump or 400,000 GaLtons Capacity Per Horr