SECTION 14550 SHAFTLESS SCREW CONVEYORS - GENERAL

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


SECTION 14550

SHAFTLESS SCREW CONVEYORS - GENERAL


PART 1 GENERAL

1.1 SECTION INCLUDES:

A. Shaftless Screw Conveyors:
1. Cake Solids Conveyor No. 1: M-8-4-1.
2. Cake Solids Conveyor No. 2: M-8-4-2.
3. Cake Solids Conveyor No. 3: M-8-4-3.
4. Cake Solids Conveyor No. 4: M-8-4-4.
5. Cake Solids Conveyor No. 5: M-8-4-5.
6. Cake Solids Conveyor No. 6: M-8-4-6.
7. Cake Solids Conveyor No. 7: M-8-4-7.
8. Truck Loading Cake Solids Conveyor No. 1: M-8-4-8.
9. Truck Loading Cake Solids Conveyor No. 2: M-8-4-9.

B. Major components included, but not limited to:
1. Spiral flighting.
2. Troughs and Liners.
3. Chutes.
4. Covers.
5. End Shaft.
6. Motor Reducer.
7. Mounting and Support Structure.
8. Slide Gate Discharge Control.
9. Electrical Controls.
10. Safety Accessories.

1.2 SYSTEM DESCRIPTION

A. Furnish a shaftless screw conveyor system for the conveyance of dewatered wastewater sludge from the belt filter presses to either the load out trucks or to the drying building.

1.3 REFERENCES

A. American Society for Testing and Materials (ASTM):
1. ASTM A36-81A - Specification for Structural Steel.

B. American Welding Society (AWS):
1. AWA D1.1-83 - Structural Welding Code: Steel.

C. National Electrical Manufacturers Association (NEMA).

D. American Gear Manufacturers Association (AGMA).

E. Conveyor Equipment Manufacturers Association (CEMA).

F. American National Standards Institute (ANSI).

G. Occupational Safety and Health Administration (OSHA).

1.4 DESIGN REQUIREMENTS

A. General Requirements:
1. See Detail Shaftless Conveyor Specifications at the end of this section.

B. Specific Requirements:
1. See Detail Shaftless Conveyor Specifications at the end of this section.

C. Design Guarantee Summary:
1. A 12,000 system and liner operating hour warranty.
2. Spiral shall be designed for a minimum of 20,000 operating hours.
3. Mechanical seals of drive shafts shall be designed for 5,000 hours without shaft wear or leakage.
4. Start-up 100% loaded, vertical and horizontal.
5. Total spiral Elongation, .04" per foot.
6. Lift and transport the sludge to the elevation required without overloading, jamming, clogging or stalling.

D. Design Calculations:
1. Safe Working Load: Design calculations with the vertical tube 100% full and at a density of 1.5x normal density (60pcf), to compensate for sludge hardening,  must be submitted for a Cylindrical Helical Spring of Rectangular Cross Section as defined in Marks, Standard Handbook for Mechanical Engineers, latest addition., calculation #13, page. Such calculations shall show that the Safe Working Load (psi) does not exceed 70% of the yield strength of the spiral and be signed by a U.S. Professional Registered Engineer.
2. Elongation or Compression: The manufacturer shall also demonstrate by submission of calculations, as above, that the "spring effect" (compression or elongation) of the spiral under fully loaded conditions shall not exceed 2.5mm per 1 meter (.04" per 1 foot) of length. The calculation used shall be: Deflection
= 7.2?nr3P(b2+h2)/b3h3Gk where: k = (4c-1)/(4c-4) and c = 2r/b and shall be signed by a Professional Engineer. (Marks Handbook, latest edition).

1.5 SUBMITTALS

A. Shop Drawings: Submit data under provisions of DIVISION 1, including the following:
1. Complete assembly and installation drawings.
2. Descriptive information on material and equipment furnished.
3. Manufacturer's qualifications.
4. Manufacturer’s design calculations.
5. Electrical motor data.
6. Submit structural calculations stamped by Professional Engineer registered in the State of Illinois for support system.
7. Provide total dead and live loads from conveyors at each support.
8. Control diagrams and panel layouts.
9. Conveyor sensors, instruments and safety switches.

B. Furnish operation and maintenance manuals under the provisions of DIVISION 1.

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

D. Submit field test documentation under the provisions of DIVISION 1.

1.6 DELIVERY, STORAGE AND HANDLING

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

1.7 MANUFACTURER'S    QUALIFICATIONS:

A. Provide a written statement indicating that the conveyor manufacturer has at least 40 operating installations of shaftless screw conveyors in North America, and at least 10 installations with vertical shaftless conveyors.

B. Description of at least three different installations handling similar material of similar size, complexity and configuration.

C. Include reference names and phone numbers for each of the three different installations.


PART 2 PRODUCTS

2.1 ACCEPTABLE MANUFACTURERS

A. Custom Conveyor Corporation, Rogers, MN.

B. JDV Equipment Corporation, Dover, NJ.

C. Jim Myers & Sons, Inc., Charlotte, NC.

D. Or Equal.

2.2 GENERAL

A. All equipment shall be the end product of one conveyors system supplier. The supplier shall be responsible for the complete system including all items covered herein.

2.3 METAL FABRICATION

A. Fabricated metal parts described herein shall conform to Section 05500.

B. All welds shall be continuous unless otherwise specified. Facing surfaces of bolted joints shall be shop primed. Facing surfaces of field welded components shall be beveled and match marked.

C. Edge Grinding. Sharp corners of all cut and sheared edges shall be made smooth.

D. Anchor bolts, fasteners, nuts, and washers: 316 stainless steel.

2.4 MATERIALS OF CONSTRUCTION:

A. Unless otherwise specified or permitted, the materials used in the fabrication of the equipment under this section shall conform to the following:

1.
Chutes: AISI 304 Stainless Steel.

2.
Troughs, End Plates, Covers: AISI 304 Stainless Steel.

3.
Supports: AISI 304 Stainless Steel.

4.
Hoppers: AISI 304 Stainless Steel.

5.
Spiral Flighting: Special Steel with a minimum hardness of 215 Brinnell.

6.
Wear Liner: Ultrahigh molecular weight (UHMW) polyethylene.

7.
Bolt, Nuts, and Washers: 18-8 Stainless Steel.


a. For Conveyor Supports: Galvanized, ASTM A153 and A385, 18-8


Stainless Steel or zinc-plated ASTM B633, SC4.


2.5


EQUIPMENT
b. For Conveyor Trough, Lids, and Drive: 18-8 Stainless Steel.

A. Drive Units:
1. Drive each spiral conveyor by a constant-speed integral gear reducer/motor drive.
2. Mount drive unit to an adapter flange mounted to the end plate of the conveyor.
3. The adapter flange shall allow the leakage of any material from the conveyor trough to atmosphere rather than into the gear reducer/ motor drive unit
4. Direct coupling of the gear reducer/motor drive unit to the end flange of the conveyor will not be acceptable.
5. Rigidly support the drive unit so there is no visible "wobble" movement under any operating condition.
6. The drive system shall be designed, at a minimum, to start the conveyor from a dead stop with the trough filled throughout its entire cross sectional area and length at 2 times the design load, in the event of a prolonged power failure or emergency system shutdown.
7. Motor:
a. Furnish motor compatible with the driven equipment herein. Motors shall be furnished as specified in Section 11338, and shall conform to the detailed requirements herein:
1) Motor nameplate horsepower: See design requirements.
2) Type drive: Constant speed.
3) Nominal (synchronous) motor rpm: 1800.
4) Motor mounting: C-faced to gear reducer.
5) Enclosure: TEFC.
6) Power: 460 volt, 3 phase, 60 Hz.
7) Service factor: 1.15 minimum.
8) 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. Mechanical Drive:
a. Motor C-faced to gear reducer.
b. Gear reducers:
1) Housing construction: Cast Iron.

2) Bearings: AGMA Class II, single or double reduction, helical gear units with high capacity roller bearings.
3) Design bearings for the thrust loads from the fully loaded startup condition and a AFBMA B10 life of 30,000 hours.
4) Provide standard air cooled unit requiring no auxiliary cooling.
5) Size the gear reducer with a torque service factor of 1.5 times the absorbed power or 1.1 times the motor nameplate, at the driven shaft speed, whichever is greater.

B. Shaftless Screw Conveyor Construction:
1. Spiral Flighting:
a. Structural Integrity, Process specification. The spiral shall be made from hot-rolled micro-alloy steel bar which is cold formed into the final specified diameter, pitch, hardness and strength. The cold-forming process must be one of the following:
1) A two stage process. Such two stages shall first consist of tightly cold rolling at zero pitch on a mandrel which uses a device to control the plastic flow of the spiral during forming and maintain a uniform outside and inside diameter thickness with no neck-down. The second stage of spiral forming shall consist of pulling the closely wound spiral in tension to the specified pitch in a device permitting free spiral rotation.
2) A single-stage process utilizing a “captured winding” technology. The diameter and pitch is formed simultaneously with a computerized numerically controlled (CNC) machine built specifically to form spirals.
b. The actual spiral manufacturer (not reseller) shall issue a mill certification verifying the fabrication process herein specified.
c. Size and Physical Properties. All spiral flighting for the system shall consist of double spirals consisting of two (2) only concentric spirals, an outer spiral and an inner spiral conforming to CEMA standards, welded together to form a single contiguous cold formed spiral with a final width of at least 4 inches. Spirals shall have a minimim cross sectional area of
2.8 in2, a minimum strength of 80,000 psi, a minimum hardness of 220 Brinell and shall be concentric to within 1/16 inch. Single width spirals
or spirals with smaller cross sectional areas or smaller inner spirals will not be accepted under any circumstances.
d. Spiral flighting for the shaftless screw conveyors shall be designed to convey material without a center shaft. The minimum overall spiral weight and surface pressure shall be as specified herein. The conveyor will include an inner flight to increase axial strength and capacity of the conveyor. The minimum spiral weight shall be specified herein.
e. Spiral flights shall be cold-formed high strength chrome alloy steel with a minimum hardness of 215 Brinell. The spiral flights shall be designed with the stability to prevent distortion and jumping in the trough. The torsional rating of the auger flighting such that, at 150% of the motor nameplate horsepower, the drive unit cannot produce more torque max. than the torsional rating of the flighting, and that the "spring effect" of

the spiral shall not exceed + 1.0 mm per 100 mm of length at maximum load conditions.
f. The spiral flighting shall be formed in sections from one continuous flat bar and shall be concentric to within 2mm +/-. Sectional flighting formed from plate shall not be permitted.
g. Spiral flighting shall have full penetration welds at all splice connections. The flights shall be aligned to assure true alignment when assembled in the field and shall be made in accordance with the supplier's requirements. The spiral flights shall be coupled to the end shaft by a flanged, bolted connection.
h. A gland packing ring consisting of two teflon coated packing rings shall seal the drive shaft at its penetration through the end plate, along with a greased labyrinth sealing system.
i. The connection of the spiral to the drive system shall be through a flanged connection plate that is welded to the spiral forming a smooth and continuous transformation from the flange plate to the spiral. The drive shaft shall have a mating flange and shall be bolted to the spiral connection plate. Additionally, a grease lubricated labyrinth seal shall be shaft mounted internally in the conveyor between the back plate and spiral coupling connection.
2. Hold Down Provisions:
a. In order to avoid excessive wear and increased maintenance the conveyors shall be designed without the use of hold down bars. In lieu of hold down bars, the supplier may furnish proprietary additional hold- down guide liners that do not interfere with the flow of conveyed product.
3. Horizontal and Inclined Troughs:
a. Troughs shall be to the dimensional standards of CEMA and enclosure classification IIE. Each conveyor trough shall be U-shaped, fabricated from a minimum 1/8 inch stainless steel plate.
b. Stiffeners shall be placed across the top of the trough and fastened to both sides of the trough to maintain trough shape and act as a face seal for the covers; apply a continuous gasket, totaling one half inch width, to the entire top face of the trough top flange and stiffeners.
c. Each trough shall be equipped with filling and/or discharge openings as required by the contract drawings. If required, each filling and discharge opening shall be flanged suitable for interconnection to other devices. Any interconnecting devices such as chutes and hoppers shall be fabricated from the same grade of material as the troughs and to a gauge to suit the applications requirements.
d. A flanged drain outlet shall be provided with each conveyor to facilitate cleaning. Outlet shall be piped to a drain as shown on the drawings, along with adequate cleaning facilities.
e. The portion of each trough that is not covered by the filling chute shall be covered by a bolted cover of a material identical to the trough. The covers shall be manufactured in maximum four foot length section to allow for access to the conveyors. To prevent unsafe access to the conveyors, quick opening covers will not be allowed.
4. Wear Liner (UHMW):

a. The wear liner for each conveyor shall be fabricated of ultra high molecular weight polyethylene. The wear liner shall be furnished in maximum four foot sections to provide ease of replacement. The liner shall be held in place with permanently welded clips; no fasteners which peretrate the trough will be allowed. The liner shall be provided with a visual indication of excess wear.
5. Inlet and Discharge Chutes:
a. Inlet and discharge chutes shall be provided by the conveyor supplier as shown on the drawings. All chutes shall be fabricated from the same material as the conveyor trough.
6. Conveyor Supports:
a. Each conveyor shall be furnished complete with supports suitable for mounting as shown on the contract drawings and as required by the supplier's design. The supports shall be shop fabricated from structural steel shapes and plates, and shall be assembled and fitted to the conveyor prior to its delivery to the jobsite. Supports and conveyor segments shall be match marked and shipped to the jobsite for assembly by the contractor. At a minimum, each conveyor shall be provided with supports at the inlet and discharge end, with intermediate supports as required. Supports shall be fabricated of AISI 304 stainless steel or equal.
b. All shop welding shall conform to the latest standards of the American Welding Society (AWS). The supports shall be designed to avoid interference with other equipment or equipment supports.
7. Structural Design:
a. All structural supporting members shall be designed such that the ratio of the unbraced length to least radius of gyration (slenderness ratio) shall not exceed 120 for any compression member and shall not exceed 240 for any tension member (of angles about Z-Z axis). In addition, all structural members and connections shall be designed so that the unit stresses     will not exceed the American Institute of Steel Construction allowable stresses by more than 1/3 when subject to loading of twice the maximum design operating torque of the spiral conveyor drive motors.

2.6 ACCESSORIES

A. Special Tools:
1. Provide special tools required for maintenance and disassembly.

B. See Detail Shaftless Conveyor Specifications at the end of this section.

2.7 FINISHING

A. Shop and Field Painting:
1. Exposed non-stainless steel metal surfaces located inside of structures and enclosures shall conform to Section 09900, System No. 5. Verify compatibility of shop prime and field paint.
2. Exposed non-stainless steel metal surfaces located outside of structures and enclosures shall conform to Section 09900, System No. 6. Verify compatibility of shop prime and field paint.

2.8 INSTRUMENTATION AND CONTROLS

A. Electrical Equipment. All electrical equipment shall conform to applicable standard of the National Electrical Manufactures Association (NEMA) and the National Electrical Code (NEC). Both power and control equipment shall be insulated for not less than 600 volts even though operating voltages may be lower.

B. Control enclosures shall be NEMA 4X, stainless steel.

C. Motion Failure Alarm Unit: Each conveyor drive unit shall be equipped with a motion failure alarm unit. The location and mounting details shall be as recommended by the conveyor manufacturer. Motion sensors shall be the non-contacting type using a probe with a pre-amplifier and main electronic assembly. The main electronic unit shall operate on 120 volt, single phase, 60 Hz power supply, and shall be housed in a NEMA 4X enclosure. A 0 to 60 second time delay relay shall be provided for startup of the conveyor.  Motion Failure unit shall have DPDT switches for interface to Motor Control Center (MCC). Conveyer supplier shall coordinate electrical requirements with MCC supplier.

D. Emergency Shutdown: Each conveyor shall be furnished with an emergency trip cord and safety switch. The cord shall run the full length of each conveyor. The trip switch shall immediately stop all conveyors when the switch is actuated. Provide DPDT switches for remote trip and trip location indication. Provide NEMA 4X prewired connection box for interface to Motor Control Center (MCC). Deliver the time delay relay to the MCC supplier for installation. Conveyer supplier shall coordinate electrical requirements with MCC supplier. Provide technical data for time delay relay to MCC supplier prior to MCC design submittal.

E. Electronic Motor Power Monitor/Trip:
1. Each conveyor motor starter shall incorporate an electronic motor power monitor/trip. The "Electronic" Detector shall connect directly to the motor cable and first measure the motor input power and then compensate for the internal losses in the motor. This will ensure that power readings under supply voltage variation conditions are automatically compensated for and that the detector will always sense the output shaft power from the electric motor. Unit shall have DPDT contact outputs.
2. The compensation setting shall be adjustable to suit any induction motor regardless of size.
3. The normal load level for the conveyor motor is to be set by an alarm level control. If the set load level is exceeded, the internal relay will change state. The output relay contact will be used for alarm and shut-down of the conveyor and for the control of other conveyors or equipment in the process.
4. The speed of trip on sensing an overload condition shall be adjustable between the ranges 0.1 and 3.0 seconds.
5. Deliver the unit to the Motor Control Center supplier for installation. Provide technical data to Motor Control Center (MCC) supplier so unit sizing and wiring requirements can be accommodated prior to MCC design submittal. Conveyer supplier shall coordinate electrical requirements with MCC supplier.

PART 3 EXECUTION

3.1 INSTALLATION

A. Install in accordance with the Drawings, shop drawings, and manufacturer's instruction.

B. Lubricate as required. Lubricate parts and components such as gear boxes and bearings prior to shipment.

3.2 MANUFACTURER'S SERVICES

A. Provide manufacturer's services under provisions of DIVISION 1.

B. Minimum Service Requirements:
1. Installation: As required for proper installation.
2. Start-up and field testing:  Two (2) eight (8) hour day (not necessarily consecutive) on site.
3. Operator training: One (1) eight (8) hour day (not necessarily consecutive) on site.

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


END OF SECTION