2320 106TH ST SW 2022-08-29 - Laserfiche WebLink

Section SOLIDS HANDLING Page 507 IMPELLER Impeller shall be of the mono-vane or two-vane,enclosed solids handling design and have pump-out vanes on the front and backside of the impeller to prevent grit and other materials from collecting in the seal area. Impeller shall not require coating.Because most impeller coatings do not remain beyond the very early life of the impeller,efficiency and other performance data submitted shall be based on performance with an uncoated impeller.Attempts to improve efficiency by coating impeller shall not be acceptable. Impellers shall be dynamically balanced.The tolerance values shall be listed below according to the International Standard Organization grade 6.3 for rotors in rigid frames.The tolerance is to be split equally between the two balance planes that are the two impeller shrouds. RPM Tolerance 3500 .01 in.—oz./lb.of impeller weight 1750 .02 in.—oz./lb.of impeller weight 1150 .026 in.—oz./lb.of impeller weight 870 .03 in. oz./lb.of impeller weight The impeller shall be threaded shaft or tapered shaft and key driven.A 300 series stainless steel washer and impeller bolt shall be used to secure the impeller to the shaft for both threaded and tapered shafts. Straight end shafts for attachment of the impeller shall not be acceptable. CASING The casing shall be of the end suction volute type having sufficient strength and thickness to withstand all stress and strain from service at full operating pressure and load. The casing shall be of the centerline discharge type equipped with an automatic pipe coupling arrangement for ease of installation and piping alignment.The design shall be such that the pumps will be automatically connected to the discharge piping when lowered into position with the guide rails.The casing shall be accurately machined and bored for register fits with the suction and casing covers. A volute case wear ring shall be provided to minimize impeller wear. The wear ring shall be 85-5-5-5 red brass or 80-10-10 bronze,ASTMB-43 and held by 300 series stainless steel fasteners.The wear ring shall be easily replaceable in the field.Wear rings of any other material shall not be acceptable. SERVICEABILITY The complete rotating assembly shall be capable of being removed from the volute without disturbing the suction piping, discharge piping,and volute.The motor housing,seal housing with seal plate and impeller still attached to the shaft shall be capable of being lifted out of the volute case from the top as one assembly. SUPPORT Though the pump may not require feet to support the unit while installed,the pump volute must have feet to support the unit when removed for service.Units that do not have feet upon which the unit can be supported when removed for service shall not be acceptable. + PENTAIR HYDROMATIC' October ©2014 Pentair Ltd.