SECTION 11394 GEAR DRIVEN SUBMERSIBLE MIXERS - GENERAL

This spec was part of the Des Plaines, IL River WRF project tat bid Feb 26, 2015.


SECTION 11394

GEAR DRIVEN SUBMERSIBLE MIXERS - GENERAL


PART 1 GENERAL

1.1 SECTION INCLUDES

A. Aeration Tank Selector Mixers: 1. M-3-1-1.
2. M-3-1-2.
3. M-3-1-3.
4. M-3-1-4.
5. M-3-2-1.
6. M-3-2-2.
7. M-3-2-3.
8. M-3-2-4.
9. M-3-3-1.
10. M-3-2-2.
11. M-3-3-3.
12. M-3-3-4.

B. RAS Denitrification Tank Mixers: 1. M-3-8-1.
2. M-3-8-2.
3. M-3-8-3.
4. M-3-8-4.

C. Filtrate Storage Tank Mixers: 1. M-7-2-1.
2. M-7-2-2.
3. M-7-2-3.

D. WAS Holding Tank Mixer No. 1: 1. M-7-2-4.

E. Fermentation Basin Mixers: 1. M-7-2-6
2. M-7-2-7
3. M-7-2-8.

F. Major Components For Each Mixer:
1. Submersible mixers.
2. Mounting systems.

1.2 SYSTEM DESCRIPTION

A. See Detail Pump Specifications at the end of this Section.

1.3 DESIGN REQUIREMENTS

A. See Detail Pump Specifications at the end of this Section.

1.4 SUBMITTALS

A. Shop Drawings: Submit under provisions of Division 1, including the following.
1. Complete assembly and installation drawings.
2. Descriptive information on material and equipment furnished.
3. Electric motor data.
4. Performance data including:
a. Flow.
b. Total power requirements in Kw.

B. Submit operations and maintenance manual under the provisions of Division 1.

C. Submit certificates of proper installation and operator training under the provisions of Division 1.

1.5 DELIVERY, STORAGE AND HANDLING

A. Deliver, store and handle the equipment under the provisions of Division 1.


PART 2 PRODUCTS

2.1 ACCEPTABLE MANUFACTURERS

A. Xylem Flygt, Pewaukee, WI.

B. Or approved equal. (See Schedule A in bid form for engineer’s designated alternate.)

2.2 GENERAL

A. Mixer shall be of the integral gear, close-coupled, submersible type. The mixer(s) shall be capable of handling screened and degritted sewage. All equipment shall be the end product of one system manufacturer. The manufacturer shall be responsible for the complete system including all items covered herein.

B. Provide each mixer with a mast.

2.3 STEEL FABRICATION

A. Metal parts as described herein conforming to Section 05500.

B. Plates and Structural Members: Type 316 stainless steel.

C. Anchor bolts, bolts, hex nuts and washers: Type 316 stainless steel.

2.4 MIXER

A. Motors:
1. Motor nameplate horsepower: See Design Requirements in Detailed Specifications.
2. Submersible enclosure with moisture resistant Class H insulation.
3. Drive type: Constant Speed.
4. Power requirements: 460 VAC, three phase, 60 Hz.
5. Continuous duty, 30 starts per hour.
6. Motor shall be inverter duty rated and meet NEMA MG1, Part 31.
7. The motor shall have NEMA B starting torque and low starting current. The motor shall not be overloaded beyond the nameplate rating under any normal conditions encountered.
8. Temperature sensors shall be embedded in motor windings.
9. The motor shall have moisture sensors located within the stator chamber.

B. Electrical Power and Signal Cable:
1. Type: Water proof.
2. Power cord entry to mixer: Protected with a compression fitting followed by sealed terminal board with permanently affixed binding posts.
3. Length (each): 30 feet. Contractor shall coordinate power and signal cable length.

C. Mixer Construction:
1. Mixer case:
a. Mixer motor housing: Gray cast iron ASTM A-48, Class 30
b. Seals: External mating parts machined and sealed with a nitrile rubber O-ring on a beveled edge.
c. Exposed fasteners: 316 series stainless steel.
2. Motor shaft construction: 431 stainless steel.
3. Propeller shaft: 431 series stainless steel
4. Gearbox:
a. Type: Two-stage, cylindrical, helical gearbox.
b. 431 series stainless steel intermediate drive shaft.
5. Bearings: Roller and angular contact bearings with a rated minimum AGMA B10 life of 50,000 hours.
6. Seals:
a. Outer seal:
1) Number of seals: One.
2) Type: Mechanical with tungsten carbide rotating seal face and tungsten carbide stationary seal face.
3) Lubrication: Immersed media.
b. Inner seal:
1) Number of seals: Two.
2) Type: Nitrile or fluorinated rubber lip seals
7. Lubrication: Provide an oil chamber for the shaft sealing system, and a second separate oil chamber for the gearbox. The drain and inspection plugs shall be easily accessible from outside the mixer.
8. Propeller:

a. Type: Three-vane, dynamically balanced, non-clogging, backswept design.
b. Construction material: Epoxy coated aluminum blades with stainless steel shaft.
9. Mixer connection to mast: 316 stainless steel.
10. Provide stainless steel lifting and support cable of adequate strength to permit raising and lowering the mixer.
11. Mounting brackets: 316 stainless steel
12. Sliding brackets: 316 stainless steel.

2.5 ACCESSORIES

A. Mast
1. The mast will be used to mount mixer during operation and guide mixer during installation and removal.
2. Materials of construction: 316 stainless steel, with a minimum mast size of 4" X 4" square.
3. Mast shall be adjustable in horizontal and vertical plane with positive lock.
4. Include all mounting hardware, including upper, lower and intermediate guide brackets and anchor bolts. Include 316 stainless steel spacer piece between mixer mounting brackets and wall of tank.
5. Include cable holder for mixer electrical cable.
6. Mast shall be non-sparking.

2.6 FINISHING

A. Shop and Field Painting: Conform to Section 09900, and the following requirements:
1. Verify compatibility of shop prime and field paint.
2. Finish all non-stainless steel and reinforced fiberglass surfaces as follows:
a. Submerged Surfaces: Conform to Section 09900, System No. 2.
b. Non-Submerged Surfaces: Conform to Section 09900, System No. 5.

2.7 INSTRUMENTATION AND CONTROL

A. Mixer Control Sensors:
1. Moisture Detectors: Provide in motor stator chamber.
a. Upon the moisture sensors sensing moisture in the stator chamber, the controls shall shut down the pump, indicate pump fail alarm, and activate the remote common fail.
2. Temperature Sensors: Provide thermal switches for each phase in pump motor.
a. Upon the temperature sensors sensing a high temperature in the motor stator, the controls shall shut down the pump, indicate pump fail alarm, and actuate the remote common fail. Automatically reset when temperature returns to normal.
3. Provide moisture and motor high temperature protection relay(s) to provide separate moisture and high temperature signals for each pump. Supervision relays shall be mounted in respective MCC.
a. Relay power supply to be 120 VAC.

PART 3 EXECUTION

3.1 INSTALLATION

A. In accordance with Drawings, shop drawings and manufacturer's instructions.

3.2 MANUFACTURER'S SERVICES

A. Provide manufacturer's services under the provisions of Division 1.

B. Minimum service requirements:
1. Installation: As required for proper installation.
2. Start-up and field testing: Five trips, one day on site per trip.
3. Operator training: One half day on site.

C. Service to Repair Defective Work: Provide during one-year warranty period under the provisions of the General Conditions.


END OF SECTION