MECHANICAL SPECIFICATIONS FOR BHD SERIES TOP ENTRY MIXERS
The mixer assembly shall consist of a horizontally mounted motor with flexible coupling, a right angle double or triple reduction speed reducer, mounting base, impeller shaft and impeller(s).
1.0 - Agitator Drive Design The reducer shall be a right angle gear drive with a fabricated steel housing, helical and spiral bevel gearing, and be designed specifically for mixer service. Helical gearing shall be surface hardened to 56-62 Rc and precision ground to minimum AGMA class 10 quality level per AGMA standard 390.03 with pinion tooth, lead and profile modifications to optimize tooth contact under load. Spiral bevel gearing shall be coarse pitch surface hardened to 56-62 Rc, shot peened and lapped in the root area for greater accuracy, load carrying capacity and life.
Reducer efficiency shall be 95-97%. The reducer shall have a single LS bevel set for each size. The helical gearing shall be contained in a HS head for easy ratio change and versatility. The reducer shall have a solid, oversized output shaft to withstand high mixer loads and avoid lateral critical speeds.
2.0 - Reducer Rating Reducer shall be rated in excess of AGMA 6010 standards. A minimum design gear strength / catalog rating of 1.5 shall be calculated for continuous operation per AGMA standards based on a maximum sump temperature of 200 degrees F and an ambient temperature of 100 degrees F. Bearing ratings shall be based on a minimum L10 life of 30,000 hours at a service factor of 1.25, 60,000 hours at a service factor of 1.50, and 140,000 hours at a service factor of 2.0, under worst conditions of loading. Service factors shall be based on motor nameplate horsepower.
3.0 - Bearings Tapered roller bearings shall be used on all shafts throughout the reducer.
4.0 - Lubrication All gearing shall be lubricated by splash, dipping in oil, or a combination of the two. A drywell around the output shaft shall prevent oil leakage. High speed and intermediate bearings shall be splash lubricated. Low speed bearings shall be grease lubricated and the upper, low speed bearing shall have a grease baffle to prevent grease from entering the unit. The housing shall include a fill hole, drain and vented dipstick.
5.0 - Shaft Design Agitator shaft stresses, considering combined torsional and bending loads, shall not exceed 6,000 psi. Non-stabilized shafts shall operate at less than 60% of first critical speed. Stabilized shafts shall operate at less than 80% of first critical speed. The shaft shall be of the specified grade of carbon or stainless steel. All points of support and impeller connection areas shall be concentric to within 0.010" tin
6.0 - Impeller Design Mixing impellers shall be of the high efficiency hydrofoil design, or as specified. The blades shall be bolted to a center hub which shall be keyed to the mixer shaft. If coated, the blades and center hub shall be welded. The impeller(s) shall be of the specified grade of carbon or stainless steel. Shaft keyway for vertical adjustment of impellers shall be provided as specified.
7.0 - Motors Electric motors shall be constant speed, 1800 or 1200 rpm, and suitable for operation on 230/460 volt, 3 phase, 60 Hertz alternating current, or as specified. The motor shall be TEFC squirrel cage induction type built in accordance with current NEMA design B standards with Class B or F insulation, and foot mounted.
8.0 - Manufacturer Mixer shall be Series BIID as manufactured by EMI / Cleveland Mixers, Clinton, CT.