7-02 25-205-B Specification - 46 41 27.33 Hyperboloid Mixers.pdf

Specification – 46 41 27.33 Hyperboloid Mixers 25-205-B PWAS and Blend Tank Mixers

SPECIFICATION

46 41 27.33 HYPERBOLOID MIXERS

1.00 GENERAL

1.01 SCOPE OF WORK

A. Hyperboloid Mixer alternative for the Blend Tank.

B. Furnish one mixer for each compartment of the Blend Tank.

C. The system shall be capable of complete homogeneous mixing of the Blend Tank containing Primary Sludge, Thickened WAS, and Scum.

A. The Manufacturer shall review the conditions of service and mounting arrangements for the

Manufacturer’s proposed mixers including basin geometry, flow path, freeboard, and shall propose mixing equipment suitable for the application and in accordance with these specifications. Any deviation from these specifications shall be identified in the proposal information accompanied by a letter of qualification documenting the variances and explaining why acceptance is in the best interest of the Owner.

1.02 STANDARDS

A. The mixing equipment furnished shall comply with the following standards as applicable

1. American Society for Testing and Materials (ASTM) Publications

2. Anti-Friction Bearing Manufacturers Association (AFBMA)

3. American Gear Manufacturers Association (AGMA) (or equivalent DIN-ISO standard)

4. American National Standards Institute (ANSI) Standards

5. Occupational Safety and Health Administration (OSHA) Standards

1.03 SYSTEM DESCRIPTION

A. Supply hyperboloid mixers for the Blend Tank as shown on the drawings. The mixers shall completely mix the contents of the tanks at maximum volume to maintain a uniform solids concentration throughout the tank.

B. The vertical mixer shall consist of an adequately sized drive motor, specially designed gear reducer with robust bearing capacity for sustaining the bending, thrust and torsional loads imposed by the cantilevered shaft and suspended impeller, vertical shaft and impeller sized to achieve complete tank mixing.

1.04 SUBMITTALS

A. All submittals shall be approved by the Engineer or the Owner prior to delivery.

1.05 ACTION SUBMITTALS / INFORMATIONAL SUBMITTALS

A. The following items shall be submitted with the proposal for bid:

1. Shop Drawings

a. Shop Drawings detailing the mixer mechanical components, materials, and coating specifications.

1) Shaft size and material

2) Impeller size, type and material

3) Complete bill of materials for the equipment.

b. Details demonstrating that the impeller components will pass through the 4 x 6 foot aluminum access hatch for the Blend Tank hatch for assembly inside the covered tanks.

2. Coatings for components that are not fabricated from stainless steel recommended slab openings and baseplate sizing and anchor arrangement.

3. Any deviations from this specification must be accompanied by a formal Certification or

Qualification Letter.

4. A general arrangement drawing of the proposed mixer for the Blend Tank.

5. Delivery conditions:

a. Specify lead times for fabrication and delivery.

B. The following items should be submitted after award:

1. CFD model – submit a report using CFD modeling or equivalent analysis demonstrating that the mixing equipment proposed will completely mix the tanks with the geometry shown on the plans and described herein. Modeling shall be based on an assumed specific gravity of 1.0 and a solids concentration of 24,000 mg/L (ppm) for the PWAS Tank and a specific gravity of 1.01 and a solids concentration of 74,000 mg/l (ppm) for the Blend Tank. The modeling report shall include data confirming that the motor horsepower proposed is adequate to impart the required mixing energy to keep the basin completely mixed at the maximum surface elevation, including consideration for electrical and mechanical efficiency.

2. Additional information to be submitted:

a. Coupling details if used

b. Shaft size and material

c. Impeller size, type and material

d. Impeller assembly details

e. Type and ratings of shaft support bearings.

f. Complete bill of materials for the equipment.

g. Recommended spare parts list.

h. The weight of each component: motor, gearbox, shafting and impeller.

i. The recommended installation, operation, and maintenance procedures.

j. Mounting details

k. The anticipated static and dynamic loads under full load

l. The total weight of the complete assembled mixer.

m. Draft O&M manual

n. Complete motor data including size, make, type and characteristics of the electric motor along with wiring diagrams.

3. Bearing life calculations.

4. Calculations supporting shaft and impeller design criteria (stresses and critical speed).

5. Layout of installed mixer with recommend placement horizontally and recommend placement of impeller or impellers if multiple impellers are proposed, clearance requirements from tank features and existing equipment and piping.

1.06 CLOSEOUT SUBMITTALS

A. Letter from the representative of the mixer manufacturer certifying that the furnished equipment was installed in accordance to the manufacturers recommendations and is ready for beneficial use

1.07 MAINTENANCE MATERIALS SUBMITTALS

A. O&M Manuals

1. O&M manuals shall demonstrate procedure to suspend wetted parts from mixer mounting plate or support structure during gearbox replacement.

2. A draft O&M manual shall be delivered with the equipment.

3. The maintenance summary form, warranty certificate, equipment installation report shall be included with final O&M manual.

1.08 DELIVERY, STORAGE, AND HANDLING

A. Certified copies of all test procedures and results shall be provided to the Owner and

Engineer prior to shipment.

B. Avoid supporting or lifting the mixer in a manner that will place excessive stress on parts or shafts that are not designed to support the weight of the unit. The mixer assembly shall be lifted by eyebolts provided in the top of motor drive or by slings.

C. The Owner shall inspect equipment prior to unloading and notify the manufacturer of any damage to delivered equipment.

1.09 WARRANTY

A. The mixer manufacturer shall warrant and guaranty the provided equipment is free from manufacturing defects and is suitable for the intended application as described herein.

Components that fail in application within 24 months from start-up and final acceptance shall be replaced without charge.

2.00 PRODUCTS

2.01 MANUFACTURERS

A. Acceptable mixer manufacturers with demonstrated competence are:

1. Invent Hyperclassic Series

2. Engineer’s approved equal

2.02 PERFORMANCE REQUIREMENTS

Location Blend Tank

Number of mixers (2) Lightnin Model No. 15QT3

Chemineer Model No. 22GTD-7.5 Invent Hyperclassic Model No. HCM 15000-34

Mounting Arrangement Baseplate Tank Dimensions

Tank Length 22’ Tank Width 12’ Tank Height 18-8"

Minimum Liquid Level 577.42 Maximum Liquid Level 591.88 Tank Ceiling Thickness 8"

Liquid being Mixed Primary Sludge, Thickened Sludge, and Scum

Maximum Percent Solids 7.4% (74,000 mg/L) Specific Gravity 1.02 Percent BioMag <0.05%

Number of Impellers 2 Vapor Seal Assembly Yes Desiccant Breather Yes

Power 460V, 3ph, 60 Hz Installed Motor Minimum Horsepower per mixer

7.5

Speed 1800 rpm Enclosure TEFC

Space Heater Yes Motor Winding Temperature

Switches Yes

2.03 MATERIALS AND/OR EQUIPMENT

A. Gear Reducer

1. The mixer gear reducer shall be mounted on a pedestal base above the tank deck with the output shaft rigid coupling below the base of the mixer to allow the disassembly of the coupling above the tank deck.

2. The gear reducer shall be designed in accordance with AGMA Standard 6010-F97 or equivalent DIN-ISO standard requirements for continuous 24-hr/day operation. Mixers gear reducers shall have a minimum AGMA (or equivalent DIN-ISO standard) service factor of 2.0. The basic rating of the gear reducer shall adhere to appropriate AGMA standards (or equivalent DIN-ISO standard) and the gear reducer shall bear an AGMA nameplate, or the manufacturer shall certify, in writing, that the gear reducer is designed to the applicable AGMA or equivalent DIN-ISO standards.

3. All gearing must be contained in a single housing. Auxiliary gear boxes to obtain double or triple reduction are not acceptable. The driven gear in any gearset (primary, intermediate or final) shall be supported by bearings on both sides of the gear.

4. Gearing shall be of AGMA quality No. 10 or better per AGMA Standard 390.03 (or equivalent DIN-ISO standard).

5. All gearing shall be immersed in a common bath of lubricating oil. All rotating parts and bearings, with the exception of the output shaft and output shaft bearings, shall be immersed in oil or splash lubricated by means of the gears or a slinger rotating on the horizontal gear shafts in the oil bath. Oil leakage down the impeller shaft shall be prevented by means of an oil dam around the shaft or a triple lip seal. The gear reducer shall be provided with a sight glass to observe oil level. Lubrication systems requiring oil pumps are not acceptable. Grease packed gear reducers are not acceptable.

6. A single oil drain shall be provided at the low point of the gear reducer to allow oil drainage. The oil drain shall be extended from the gear reducer to prevent leakage and spillage during oil changes.

7. All gear reducer bearings shall be antifriction type single or double row tapered roller bearings and shall have a minimum rated L-10 life of 100,000 hours.

8. The thermal rating of the gear reducer shall exceed the design mechanical rating to eliminate the need for external coolers. External cooling devices are not acceptable.

9. Where required in the mixer schedule, the mixer base and output shaft shall be furnished with an EPDM vapor seal assembly to prevent foul air from escaping through the shaft openings in the slab or baseplate

B. Mixer Shaft

1. The mixer shaft and all materials located below the operating deck shall be constructed of 316 stainless steel or fiberglass reinforced pipe (FRP).

2. Shaft diameter shall be determined by an analysis of torques, bending moment, thrust, pressure, temperature, and critical speed. The shaft shall be designed such that the maximum combined stress considering torsion, bending and thrust shall not exceed 8,000 psi under maximum operating loads. It shall be of overhung design. The use of in-tank steady bearings is not permitted.

3. The shaft-impeller system design shall be such that its operating speed shall not exceed

70% of its first lateral critical speed. The use of stabilizing rings or fins will not influence this limitation.

4. Mixer shaft straightness, rigid coupling squareness, and gear reducer output shaft accuracy must be such that the maximum total indicated runout at the lower end of the mixer shaft does not exceed 1/8-inch per every 10 ft of shaft length, as measured when turning over by hand.

5. Shaft design shall include features to allow all wetted parts to be suspended from the mixer pedestal base or support structure during gearbox replacement. Furnish all special tools, adapters, etc. required to suspend wetted parts and reconnect during gearbox replacement.

C. Mixer Impeller

1. Impellers shall be connected to the mixer shaft with laminated stainless steel insert nuts.

The shape of the impeller shall be hyperboloid (continuous shape) with integral motion fins on the top surface to create the appropriate swirling motion.

2. Impellers may be radial as recommended by the manufacturer.

3. Each impeller shall be constructed of fiberglass reinforced plastic. Bolts for impellers shall be constructed of 316 stainless steel. Impeller shall be assembled to allow removal through the 4 x 6 foot aluminum access hatch the Blend Tank.

4. The impeller shall be dynamically and hydraulically stable and shall not cause the equipment to overload over the specified range of liquid levels with up to the specified flow rates through the tanks.

5. Where mixers are required to be equipped with a bottom guide bushing to minimize shaft deflection and to account for variable tank floor elevation, the guiding bushing shall be constructed of 316 stainless steel. Bottom guides are required for the Blend Tank.

6. The use of stabilizer rings will not be permitted.

7. The impellers shall be designed to prevent vortexing.

D. Guards

1. All rotating shafts above the deck shall be provided with safety guards.

E. Mounting Arrangement and Anchors

1. Shear and tensile loads to be provided by mixer manufacturer. The mixer manufacturer will also supply any required drawings for setting the anchor bolts.

2. The mixer housing shall mount to a baseplate minimum 1 inch thick; the base plate shall be anchored to the concrete deck. The baseplate shall be steel, and epoxy coated after fabrication. Concrete anchors shall be recommended by the manufacturer but not less than one inch in diameter and 304 stainless steel. Baseplate assembly shall fully cover the tank opening.

F. Drive Motors

1. Drive motors shall be 3 Phase suitable for outdoor application in TEFC enclosures.

2. Motors shall be rated for severe or chemical duty

3. Motors shall have minimum 1.15 SF.

4. A corrosion proof nameplate shall be provided with each motor and shall be securely fastened thereto. Information shall include voltage, speed, phase, insulation class, amperage, service factor, wiring diagram, and motor serial number.

5. The motors shall be Class F insulation and Class B temperature rise

2.04 PAINTING

A. Manufacturers factory finish shall be suitable for exposed applications without recoating in field.

2.05 EQUIPMENT IDENTIFICATION

A. The equipment shall be provided with a substantial stainless-steel nameplate, securely fastened in a conspicuous place and clearly inscribed with the manufacturer's name, year of manufacture, serial number, and principal rating data.

3.00 EXECUTION

3.01 INSTALLATION

A. Equipment shall be installed by others in accordance with the manufacturer’s submittals, drawings, and written installation instructions.

3.02 INSPECTION AND TESTING

A. All sampling and testing to be performed by manufacturer during performance test.

B. The Manufacturer recommended test is required to show complete mixing of the tank for the

Blend Tank.

C. Should any portion of the system fail to meet the requirements specified, the Manufacturer shall make modifications such that the system meets the requirements of this Specification, at no additional cost to the Owner.

3.03 MANUFACTURER FIELD SERVICES

A. The manufacturer shall include the services of a manufacturer's factory trained service technician for field supervision during installation, certification the Manufacturers mixers have been installed as recommended by the manufacturer, and to instruct Owner personnel on operation and maintenance procedures as applicable.

1. A factory trained representative for the equipment specified herein shall be present at the jobsite and/or classroom designated by the Owner for installation inspection, plant startup, functional testing, and operator instructions; travel time excluded.

a. Installation: Assist in installation and leveling of mixer/aerator and in coordinating electrical and control connections or any other miscellaneous coordination: 1 Man-day for each tank (non-consecutive): Two (2) Man-day (8 hours)

b. Start-up and Operation and maintenance (O&M) instructions: One (1) Man-day (8 hours)

c. Certification and Performance Testing: One (1) Man-day (8 hours)

2. If there are difficulties in operation of the equipment due to the manufacturer’s design or fabrication, additional service shall be provided at no additional cost to the Owner.

B. The mixer manufacturer’s representative shall provide a report after inspection and testing has occurred. The report shall certify that the mixer is installed per the manufacturer’s recommendations and is ready for beneficial use by the Owner.

END OF SECTION