The pump shall be designed for pumping ______ gallons per minute of water at ______ ft. total dynamic head (including velocity head) with ______ ft. minimum submergence and with a minimum efficiency of ______%. The pump shall be operated at a maximum speed of ______ RPM.
Pump bowl and suction bell shall be of ASTM A48 Class 30 close-grained cast iron. The suction bell shall have a flared inlet designed to reduce entrance losses and a sufficient number of vanes to support the bearing housing. Both the suction bell and the pump bowl shall have sleeve type bronze or fluted neoprene bearings. With oil lubricated column the pump bowl shall have a drain-port with sufficient area to drain the oil that passes through the pump bowl bearing and the suction bell bearing shall be grease packed and be protected by the pump impeller/propeller. The impeller/propeller shall be made of bronze and shall be fastened to the pump shaft in such a manner as to be readily removable and to be able to prevent damage from reverse rotation. The pump shaft shall be of sufficient diameter to transmit the required horsepower with a liberal safety factor. The shaft material shall be high chrome stainless steel of ASTM A276 Grade 416, ground and polished with a surface finish not to exceed 40 rms.
DISCHARGE ELBOW AND COLUMN ASSEMBLY
The column and discharge elbow shall support the driver and direct the flow of water from the pump bowl to the horizontal (underground) (surface) discharge pipe located as specified. It should consist of an elbow, necessary sections of column, line shaft, line shaft couplings and bearings. For an oil lubricated pump, it shall also include shaft enclosing tube, tube tension device and gravity lubricator. For a water lubricated pump, it shall include an extractor or stuffing box.
The line shaft shall be ASTM A276 Grade 416 stainless steel, ground and polished with a surface finish not to exceed 40 rms. It shall be of ample size to operate the pump without distortion or vibration and shall be capable of carrying the maximum horsepower that may be generated by the motor. The butting ends shall be machined, faced and recessed square to the axis of the shaft. To insure accurate alignment, the shaft shall be straight within 0.005 inches total indicator reading per 10 foot section. The ends of the shaft shall be accurately machine threaded for connection. Shaft couplings shall be bored and threaded from solid steel bars designed with a safety factor of one and one half times that of each shaft. The threads shall be left hand to tighten during pump operation.
SHAFT ENCLOSING TUBING (OIL LUBRICATED)
The shaft enclosing tubing to be furnished under this specification shall be of sufficient diameter to provide adequate lubrication under any operation conditions. The enclosing tube shall be black, ASTM A120, extra heavy weight, continuous weld prime line pipe. Both ends of each tubing length shall be bored, faced, and inside threaded with a Class 3A thread. The ends of the tubing shall be square with the axis and shall butt to insure accurate alignment. The lengths shall be interchangeable with the exception of the top section which shall be designed for applying proper tension to the tubing.
LINE SHAFT BEARINGS (OIL LUBRICATED)
The line shaft bearings which serve as couplings for the shaft tubing shall be spaced at each tubing length (not to exceed 5’) to maintain alignment of pump shafting and to prevent excessive vibration. They shall be of bronze alloy, equivalent to SAE 660, machined, threaded and grooved for proper lubrication. Bearing spacing not to exceed 5′.
The strainer basket shall be of the rod type or galvanized wire mesh. The rod type strainer shall bolt to the bottom of the suction bell. The rod diameter shall be a minimum 1/2 inch.