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

Section SOLIDS HANDLING Page 506 MOTOR The stator,rotor and bearings shall be mounted in a sealed submersible type housing. The stator windings shall have Class F insulation (155°C or 311°F)or Class H insulation(180°C or 356°F)and a dielectric oil-filled motor,NEMA B design.Further protection shall be provided by using on-winding thermal sensors.Because air-filled motors do not dissipate heat as efficiently as oil-filled motors,air-filled designs shall not be acceptable. The pump and motor shall be specifically designed so that they may be operated partially or completely submerged in the liquid being pumped.The pump shall not require cooling water jackets.Dependence upon,or use of,water jackets for supplemental cooling shall not be acceptable. Stators shall be securely held in place with a removable end ring and threaded fasteners so they may be easily removed.No special tools shall be required for pump and motor disassembly. Pump shall be equipped with heat sensors.The heat sensor shall be a low resistance,bi-metal disc that is temperature sensitive. It shall be mounted directly on the stator windings and sized to open at 120°C and automatically reset at 30-35°C differential.The sensors shall be connected in series with motor starter coil so that the starter shall be equipped with 3 leg overload heaters, making all normal overloads protected by the starter. BEARINGS AND SHAFT An upper radial bearing and a lower thrust bearing shall be required. These shall be heavy-duty single row ball bearings that are permanently lubricated by the dielectric oil that fills the motor housing. Double row, sealed grease packed bearings shall not be acceptable.Bearings that require lubrication according to a prescribed schedule shall not be acceptable.The upper radial bearing and lower thrust bearing shall have a minimum B-10 life of 50,000 hours. The shaft shall be machined from a solid 400 series stainless steel forging and be a design that is of large diameter with minimum overhang to reduce shaft deflection and prolong bearing life. SEALS The pump shall have two mechanical seals,mounted in tandem,with an oil chamber between the seals.Type 21 seals shall be used with the rotating seal faces being carbon and the stationary seal faces to be ceramic.The lower seal shall be replaceable without disassembly of the seal chamber and without the use of special tools. Pump-out vanes shall be present on the backside of the impeller to keep contaminates out of the seal area. Units that require the use of tungsten-carbide seals or foreign manufactured seals shall not be acceptable. The pump shall be equipped with a seal leak detection probe and warning system.This shall be designed to alert maintenance personnel of lower seal failure without having to take the unit out of service for inspection or requiring access for checking seal chamber oil level and consistency. There shall be an electric probe or seal failure sensor installed in the seal chamber between the two tandem mechanical seals.If the lower seal fails,contaminants that enter the seal chamber shall be detected by the sensor,which sends a signal to operate the specified warning device. Units equipped with opposed mechanical seals shall not be acceptable. ►� PENTAIR HYDROMATIC' October ©2014 Pentair Ltd.